Research Wim Martinet

Abstract

Cell death is a prominent feature of advanced plaques with a major impact on atherogenesis and plaque destabilization. According to morphological studies, the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrotic cell death. Gasdermins have recently been identified as essential effector molecules in different types of programmed necrosis by forming pores in the plasma membrane. Besides the canonical caspase-1/inflammasome pathway that activates gasdermin D, gasdermin E was recently identified as an alternative key executioner of programmed necrosis after cleavage by caspase-3. Although numerous studies underscored the importance of caspase-3-mediated cell death in atherosclerosis, the role and impact of gasdermin E-mediated necrotic cell death is currently unknown. Nonetheless, necrosis has become an important and attractive research target to stabilize rupture-prone plaques. Therefore, this research proposal defines the following objectives: (1) extensive analysis of gasdermin E-mediated necrosis in both human and mouse plaques, (2) identification of the molecular mechanisms of gasdermin E-mediated necrosis in atherosclerosis, (3) inhibition of plaque necrosis using gasdermin E knockout mice, and (4) characterization of autophagy as a natural defense mechanism against gasdermin E-mediated necrosis. In general, this project will allow a significant advance in the fundamental understanding of regulated necrosis in atherosclerosis.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido
• Fellow: Zurek Michelle

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In tumors, autophagy acts as a survival mechanism that protects tumor cells from cytotoxic drugs and the hypoxic and nutrient-deprived tumor microenvironment. Inhibition of autophagy has been shown to increase and restore sensitivity to cytotoxic therapy and to promote tumor cell death, both in vitro and in vivo. Recently, there is also evidence that autophagy plays a critical role in tumoral angiogenesis and lymphangiogenesis. To date, only the weak, non-specific autophagy inhibitor chloroquine is clinically used in oncology. Other, more specific autophagy blockers have been reported, e.g. inhibitors of the autophagy kinases ULK1/2 and Vps34. While potent in vitro, clinical translation is difficult: obtaining reproducible autophagy inhibition in vivo is challenging with these agents. This sets the stage for this project, which aims to prepare and investigate the following 2 novel compound types: 1) ULK1/2 and Vps34 PROTACs. These compounds could be especially efficient at inhibiting autophagy because they clear ULK1/2 or Vps34 from the cytosol: this not only abrogates their kinase activities, but also additional functionality that is exerted through protein-protein interactions. 2) Tumor-selective kinase inhibitors and PROTACs. Selective delivery of autophagy inhibitors to tumors would allow both intratumoral accumulation of the molecules and reduce exposure of healthy tissue. To this end, we will prepare peptide-drug conjugates of ULK1/2 and Vps34 inhibitors and PROTACs.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Cianni Lorenzo
• Co-promoter: Martinet Wim
• Fellow: Willemsen Martijn

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Autophagy is a highly conserved intracellular recycling process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is a main feature of several human pathologies such as neurodegeneration, cancer and cardiovascular disease. Accordingly, there is strong interest in pharmacological agents that stimulate autophagy. Yet, the unequivocal validation of autophagy induction as a therapeutic strategy is currently lacking. Many obstacles remain, including the absence of potent, selective, and druglike autophagy inducers and easily transmissible preclinical results obtained with such compounds. This project aims to address the existing limitations in the field. We recently performed a phenotypic high-throughput screen on a library of diverse lead-like molecules and several novel autophagy-inducing molecules were identified. Moreover, derivatives of the initial hits were synthesized in order to obtain drug-like compounds with a more favorable biopharmaceutical profile. In this proposal, the autophagy-inducing potency and pharmacokinetic profile of the identified hits and derivatives will be thoroughly characterized both in vitro and in vivo. Moreover, the most promising autophagy inducer will be tested in a mouse model of advanced atherosclerosis. We expect that the knowledge and molecular tools generated by this project will have a major impact on (pre)clinical drug research and may improve human health through autophagy induction.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: Van Der Veken Pieter
• Fellow: Mertens Freke

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Autophagy is a ubiquitous physiological process that breaks down and recycles obsolete or dysfunctional cellular components. It helps cells to survive during times of nutrient deprivation and supports clearance of protein aggregates and damaged subcellular components, thereby avoiding proteotoxic stress. Impaired autophagy has been identified as a hallmark of multiple pathologies, among others cardiovascular disease and metabolic disorders. During the last years, preclinical evidence has mounted that pharmacologically inducing autophagy, could be a game-changer in the treatment of these diseases. From a safety and efficiency perspective, one might question whether systemic treatment with autophagy inducers is the optimal way to address the localized autophagy defects that are present in most of these diseases. With that respect, we propose a cell-type specific strategy for delivering autophagy inducers. More specifically, we will prepare autophagy inducers that are chemically derivatized to target two cell types that play a key role in diseases characterized by impaired autophagy: 1) vascular endothelium (atherosclerosis) and 2) hepatocytes (NAFLD/Non-alcoholic fatty liver disease). All new compounds will be thoroughly investigated in vitro and in cells. The most promising compound will be submitted to in vivo investigation in a murine model of either atherosclerosis or NAFLD.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Cianni Lorenzo
• Co-promoter: Martinet Wim
• Fellow: Grintsevich Sergei

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Life expectancy keeps increasing in developed countries. Because age is an important independent risk factor for cardiovascular disease (CVD), its impact on healthcare systems is substantial. Aging is accompanied by impaired autophagy, which triggers a strong interest in this highly conserved intracellular recycling process in various disease areas including CVD. We previously reported that impaired autophagy in vascular smooth muscle cells affects vasomotor function and accelerates the development of atherosclerotic plaques. However, the role of endothelial autophagy in vascular disease remains poorly understood, despite numerous studies indicating that endothelial autophagy maintains normal vessel wall biology. In this project, we would like to study in more depth the role and significance of endothelial autophagy in vascular disease by using an appropriate mouse model for defective autophagy in endothelial cells (ECs). Special attention will be given to how endothelial autophagy influences vascular reactivity, arterial stiffness, blood pressure and atherogenesis. A second aim is the prevention of vascular disease by stimulating autophagy selectively in ECs by using a key autophagy inducer linked to an EC-specific homing peptide, thereby avoiding systemic side effects. The knowledge acquired within this project will allow a significant advance in the general understanding of autophagy (and its impaired function) in vascular disease.

Researcher(s)

• Promoter: Martinet Wim
• Fellow: Roeyen Eline

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Obesity is becoming a global threat, not only reducing female fertility but also affecting the offspring's health. The quality of the oocytes developing under obesity-associated metabolic stress is significantly deteriorated, mainly due to oxidative stress (OS) and mitochondrial (MT) dysfunction. The defective mitochondria are transferred to the embryo, with persistently high OS levels, leading to transcriptomic, epigenetic and phenotypic alterations, and low pregnancy rates, even when clinical assisted reproductive treatments are used. Early embryos lack the machinery to re-establish cellular homeostasis or activate mitophagy and mitogenesis to rejuvenate MT functions and support embryo survival. Current clinical interventions during the preconception period, such as diet caloric normalization or restriction, have been shown to restore systemic metabolic health but fail to rescue oocyte MT functions. Emerging MT-targeted antioxidants and compounds inducing mitophagy have been proven efficient in combating MT dysfunction in several metabolic diseases. These treatments could enhance oocyte quality when supplemented in vitro, however their efficiency to enhance MT functions in metabolically stressed oocytes from obese females in vivo has not been previously investigated, yet very topical and important. In this project we hypothesize that treatments with pharmaceutical compounds can specifically support MT functions in oocytes. A targeted reduction of MT oxidative stress or activation of mitophagy and mitogenesis during the preconception period in obese females can improve oocyte quality and oocyte developmental competence. We believe that this approach will also improve embryo quality and normalize epigenetic programming during subsequent development resulting in better offspring health. Therefore, we firstly aim to enhance oocyte MT functions and quality in vivo in obese females using MitoQ, a MT targeted antioxidant (i.e. for MT TARGETED SUPPORT), or Liraglutide, a potent anti-diabetic medication increasingly used for weight management, known to stimulate mitophagy via SIRT1-PINK1-Parkin dependent ubiquitin pathway (i.e. for REPAIR and REJUVINATION). We will use a validated outbred Swiss mouse model to increase the pathophysiological relevance to the humans. Secondly, we aim to test and compare the efficiency of different MT-targeted therapies when supplemented in vitro during culture of embryos derived from mature oocytes collected from obese mice (EMBRYO RESCUE). We will compare the effects of MitoQ, Liraglutide, as well as Rapamycin to induce mitophagy by inhibiting the mTOR-TORC1 pathways. In addition, we will examine if the MT therapy could alleviate obesity-induced epigenetic alterations in the produced embryos. Lastly and most importantly, we are also planning to follow up the effect of the treatments on offspring health after embryo transfer, an insight which is lacking in the majority of studies in this field. Taken the pandemic burden of obesity and metabolic disorders, this fundamental insight is needed as a basis to develop efficient strategies to improve human fertility at the time of conception by targeting oocyte mitochondria. We furthermore need this evidence-based proof of concept to prioritize the health outcomes in the children born from obese mothers. The project benefits from the combined expertise of the research team at the Gamete Research centre, lead by Prof. Jo Leroy, as well as the expertise in autophagy screening and targeting provided by Prof. Wim Martinet (Laboratory of Physiopharmacology).

Researcher(s)

• Promoter: Leroy Jo
• Co-promoter: Marei Waleed
• Co-promoter: Martinet Wim
• Fellow: Loier Lien

Research team(s)

• Veterinary physiology and biochemistry

Project type(s)

• Research Project

Abstract

Dipeptidyl-peptidase 9 (DPP9) is a proline-selective serine protease that belongs to the peptidase S9 family. During recent years, DPP9 inhibition has shown to cause pyroptosis, selectively in acute myeloid leukemia cells. Pyroptosis is a lytic form of programmed cell death, that has mainly been observed in immune cells. The process typically recruits and activates other immune cells and inflammatory mediators, causing a localized activation of the innate immune system. This is particularly appealing for leukemia treatment, because the immune-response to leukemic cells is typically severely subdued. Recent mechanistic insight suggests that native DPP9 suppresses pyroptosis through a stabilizing protein-protein interaction (PPI) with the NLRP1 inflammasome sensor. Furthermore, DPP9 inhibition with small molecules only has a mildly destabilizing effect on the [DPP9-NLRP1] PPI. This proposal suggests the targeted clearance of DPP9 from the cytoplasm in acute myeloid leukemia cells to cause pyroptosis through enhanced NLRP1 activation. PROTACs and AUTACs are heterobifunctional molecules that mediate the degradation of a protein of interest (POI) by hijacking cell's own proteasome and autophagic system, respectively. The implementation of PROTAC and AUTAC technologies for targeted clearance of DPP9 and consequent pyroptosis induction in acute myeloid leukemia cell lines is proposed in this project. PROTAC and AUTAC molecules will be designed and synthesized, followed by in vitro evaluation of their cell permeability, DPP9-engagement, DPP9 clearance potency and selectivity, and dose/time dependence of DPP9 clearance. Furthermore, a comparison of the pyroptosissignatures of PROTACs, AUTACs and DPP9 inhibitors will be performed. Overall, this proposal can provide a superior therapeutic strategy to AML and other cancer types.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Martinet Wim
• Fellow: Florindo Espadinha Margarida

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Morphological studies indicate that the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrosis. Although the role of necrosis in atherosclerosis remains ill-defined, a growing body of evidence suggests that necrotic death stimulates atherogenesis and plaque instability through induction of inflammation and enlargement of a central necrotic core. For a long time, necrosis in advanced plaques has been considered as a merely accidental and uncontrolled form of cell death, but recent data indicate that it can also occur in a regulated fashion through induction of necroptosis. However, it should be noted that other examples of regulated necrosis such as ferroptosis are emerging. Moreover, gasdermins have recently been identified as essential effector molecules in different types of programmed necrosis by forming pores in the plasma membrane. Because regulated necrosis is considered an important pharmacological target to stabilize plaques, the following objectives are defined: (1) identification of ferroptosis and gasdermin E-mediated necrosis in both human and mouse plaques, (2) inhibition of both processes via genetic or pharmacological approaches, and (3) characterization of autophagy as a natural defense mechanism against necrosis in atherosclerosis. This project may lead to the discovery of novel anti-atherosclerosis therapies, and will allow a significant advance in the fundamental understanding of regulated necrosis in atherosclerosis.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Elastin is responsible for the elasticity of the vessel wall, but due to repetitive stretches and relaxations as we age, it will fracture, leading to arterial stiffness and the release of soluble elastin-derived peptides (EDPs). Some of these EDPs are biologically active and can play a role in the development of cardiovascular disease (CVD). Existing literature points towards a decline in autophagy by EDPs. Autophagy is a protective mechanism, that recycles damaged cell products into building blocks that are used to maintain cellular health. Lower autophagy levels can contribute to vascular disease. If EDPs can reduce autophagy, this might be an important mechanism by which they exert their detrimental effects. However, this has never been proven. Therefore, we would like to investigate whether EDPs can reduce autophagy and how this affects arterial stiffness. This will answer three research questions: (1) Can EDP signalling affect cellular function and lead to autophagy deficiency in vascular cells? (2) What is the role of EDPs in the progression of arterial stiffness and (3) is autophagy deficiency responsible for the observed effects? Overall, this research plan aims to better understand the role of EDPs in autophagy decline, vascular ageing and arterial stiffness in order to prevent or slow down this process and to improve quality of life.

Researcher(s)

• Promoter: Roth Lynn
• Co-promoter: Martinet Wim
• Fellow: Van Praet Melissa

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In the last century, the enormous improvements in life expectancy have led to a global population that has grown considerably older. The number of people over 65 is expected to increase from an estimated 524 million in 2010 to nearly 1.5 billion in 2050 (source WHO). Therefore, age-related diseases such as cardiovascular disease (CVD), diabetes, kidney disease and neurological disorders have a significant impact on our quality of life and represent a huge social and economic burden. Vascular ageing is characterized by structural and functional changes in the wall of large arteries, leading to arterial stiffness, which is an independent predictor of cardiovascular complications. Moreover, there is increasing evidence that it is a key driving force for multiple age-related cardiac, renal and cerebral pathologies. This challenge aims to better understand the pathophysiological mechanisms causing vascular ageing and arterial stiffness in order to prevent or delay this process and improve quality of life. The focus will be on the role of autophagy in vascular ageing, which is a homeostatic process that supports cell survival under stressful conditions. The autophagic process becomes impaired as we age, contributing to the development of age-related diseases. However, many questions about why autophagy declines and how it can be therapeutically targeted, still remain unanswered.

Researcher(s)

• Promoter: Roth Lynn
• Co-promoter: De Meyer Guido
• Co-promoter: Guns Pieter-Jan
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Western-style diets are hypercaloric and characterized by high fat and high sugar content. They are responsible for an epidemic of cardiovascular disease, including atherosclerosis (AS), and metabolic disorders, including Non-Alcoholic Fatty Liver Disease (NAFLD). The European population is becoming increasingly exposed to these disorders, for which the only available therapeutic option is lifestyle modification. This typically involves dietary changes and physical activity, but patient compliance with these measures tends to be suboptimal. Pharmacological treatment options could therefore have significant potential to improve patient perspectives. With this respect, pharmacological induction of autophagy is intensively studied. Autophagy is the main detoxification and recycling mechanism of cells, and it has been shown to become dysfunctional in AS and NAFLD. Small molecules that can stimulate the process have been demonstrated to treat the diseases in animal models. However, all known autophagy-inducing molecules lack specificity, and this is suspected to cause systemic toxicity during chronic application in humans. In this proposal, we deliver molecules that avoid systemic exposure by targeting them specifically to disease-relevant tissues. First, potent autophagy inducers will be chemically linked to selected 'homing peptides' that we hypothesize to deliver the molecules to dysfunctional vascular endothelial cells in atherosclerosis. Similarly, we hypothesize that triantennary N-acetyl galactosamine (GN3) can guide autophagy inducers to liver cells in the context of NAFLD. All molecules that are prepared in this project will be first studied in cells: both autophagy induction potential and tissue targeting will be evaluated thoroughly. For the best molecule prepared (either endothelial- or liver-targeted), in vivo proof-of-concept will be delivered. In this way, the proposal's potential to deliver new, relevant drugs will be maximally valorized.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Martinet Wim
• Fellow: Cianni Lorenzo

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Autophagy is a ubiquitous process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is currently emerging as a hallmark of many diseases. In this framework, there is strong interest in pharmacological agents that stimulate autophagy (so-called 'autophagy inducers'), as a potential treatment for these diseases. The unequivocal validation of autophagy induction as a therapeutic strategy, however, is far from established. Many obstacles persist, including the lack of druglike, selective autophagy inducers and readily translatable preclinical results that are obtained with such compounds. In addition, the availability of reliable biomarkers for autophagy and additional fundamental safety data for the approach, would strongly contribute to its validation. This proposal addresses existing limitations in the state-of-the art in the domain. We have recently carried out a phenotypic High-Throughput Screen (HTS) on a curated compound library. Members in this library were preselected from different providers based on in silico druglikeness scores. One compound family that was identified in the screen and maximally validated prior to this application, will be further optimized chemically for autophagy induction potency and biopharmaceutical properties. The biopharmaceutical profile of the best new representative will be thoroughly characterized in vivo, both involving PET-based pharmacokinetics and phenotypic pharmacodynamics. The compound will subsequently be investigated in two mouse models of diseases characterized by defective autophagy: atherosclerosis and Charcot-Marie-Tooth periferal neuropathy. In addition, we propose to investigate whether autophagy induction is intrinsically sufficiently safe as a therapeutic strategy. Existing hypotheses that autophagy induction could accelerate tumorigenesis and/or tumor growth will be investigated in vivo. In the same framework, metabolomics will be relied on to monitor eventual cellular stress fingerprints that result from chronic or long-term autophagy stimulation. Finally, metabolomics will also be relied on to identify cellular biomarkers of autophagy induction. The latter will be validated in plasma samples of animals that were systemically treated with autophagy inducers. Combined, we expect the knowledge and tools that are generated by this proposal to have strong impact on the field of autophagy research and ongoing endeavors to validate autophagy induction as a therapeutic strategy.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Martinet Wim
• Co-promoter: Stroobants Sigrid
• Co-promoter: Timmerman Vincent
• Co-promoter: van Nuijs Alexander

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Autophagy is crucial in the (patho)physiology, including inflammation, infection and cancer. Autophagy functions as a survival mechanism by maintaining viability during periods of stress, and by removing damaged organelles and toxic metabolites, such as protein aggregates or intracellular pathogens. The Atlantis research consortium (AuTophagy in InfLAmmatioN and inflammaTory dISorders) brings together a team of expert investigators from the complementary fields of autophagy, (cancer) cell death signaling, inflammation signaling, angiogenesis and atherosclerosis, and drug screening and medicinal chemistry. We will study in an integrated way the impact of autophagy and its pharmacological modulation in various vascular diseases with a focus on the endothelium and its functional interaction with immune cells in sepsis, tumor-driven (lymph)angiogenesis, and atherosclerosis.

Researcher(s)

• Promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

New drug candidates often have off-target effects resulting in adverse events, thus representing a major limitation for drug R&D. Safety Pharmacology (SP) aims to detect, understand and reduce undesirable pharmacodynamic effects early-on. Especially, cardiovascular (CV) toxicity is problematic, as it is the most prevalent reason for failure during preclinical development. Moreover, CV toxicity remains a key reason for drug attrition during clinical development and beyond. This indicates current SP screens fail to detect a number of (late-onset) functional or structural CV toxicities. Additionally, SP uses a significant number of laboratory animals, thereby creating opportunities for a better implementation of the 3Rs. The vision of INSPIRE is to advance and "inspire" SP by exploring new technological capabilities (WP1), addressing emerging CV concerns (WP2) and delivering new validated solutions for CV safety screening (WP3). To this end, INSPIRE unites expertise from academic teams, technology-providers, pharmaceutical companies, regulators and hospitals to create a European training platform for 15 Early Stage Researchers (ESRs). Key innovative aspects of INSPIRE include: i) in vitro humanized cardiomyocytes assays, ii) unparalleled in vivo hardware/software solutions, iii) in silico predictions of haemodynamics, iv) mass spectroscopy imaging of drug exposure, v) exploration of mechanisms of late-onset CV toxicity, as observed in cardio-oncology, and vi) early integration of feedback from industry and regulators. Overall, INSPIRE constitutes a multidisciplinary and intersectoral training programme (WP4) with a balanced combination of hands-on research training, intersectoral secondments, local courses and network-wide events on scientific and transferable skills, enabling future R&I collaborations. Hence, INSPIRE will equip the future generation of SP scientists with a wide range of scientific knowledge and the ability to adapt to a dynamic ever-changing industry.

Researcher(s)

• Promoter: Guns Pieter-Jan
• Co-promoter: De Meyer Guido
• Co-promoter: Heidbuchel Hein
• Co-promoter: Martinet Wim
• Co-promoter: Segers Vincent
• Co-promoter: Van Craenenbroeck Emeline

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Autophagy is a highly conserved intracellular recycling process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is a main feature of several human pathologies such as neurodegeneration, cancer and cardiovascular disease. Accordingly, there is strong interest in pharmacological agents that stimulate autophagy. Yet, the unequivocal validation of autophagy induction as a therapeutic strategy is currently lacking. Many obstacles remain, including the absence of potent, selective, and druglike autophagy inducers and easily transmissible preclinical results obtained with such compounds. This project aims to address the existing limitations in the field. We recently performed a phenotypic high-throughput screen on a library of diverse lead-like molecules and several novel autophagy-inducing molecules were identified. Moreover, derivatives of the initial hits were synthesized in order to obtain drug-like compounds with a more favorable biopharmaceutical profile. In this proposal, the autophagy-inducing potency and pharmacokinetic profile of the identified hits and derivatives will be thoroughly characterized both in vitro and in vivo. Moreover, the most promising autophagy inducer will be tested in a mouse model of advanced atherosclerosis. We expect that the knowledge and molecular tools generated by this project will have a major impact on (pre)clinical drug research and may improve human health through autophagy induction.

Researcher(s)

• Promoter: Martinet Wim
• Fellow: Mertens Freke

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Autophagy is a normal physiological process that removes unnecessary or dysfunctional cellular components from the cytoplasm. Defective autophagy is currently emerging as a hallmark feature of many diseases. In this framework, basic research and drug development have a strong need for reliable, druglike autophagy inducers. In response, we recently carried out a phenotypic highthroughput screen on ~11.000 compounds that were preselected based on druglikeness parameters. In total, 36 potent autophagy inducers were identified. They belong to 10 distinct chemical families that previously have not been associated with autophagy induction. After thorough validation, potency and gross mode-of-action studies, 2 chemical families have been prioritized for further investigation. The proposal comprises the thorough investigation of the most promising family. Structure-Activity Relationships will be constructed and the pharmacophore identified. In addition, chemical optimization will be pursued to obtain analogues with further improved potency and a maximally favorable physico-chemical profile. All novel compounds will be thoroughly investigated in cells and the best performing molecule will be evaluated in an in vivo model of atherosclerosis. Finally, biochemical target identification will be approached via an ensemble of affinity-chromatography, phosphoproteomics and a kinase activity assay.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Augustyns Koen
• Co-promoter: Martinet Wim
• Fellow: Bozdag Murat

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Despite recent scientific and technological advances, vascular disease remains the leading cause of morbidity and mortality in Europe. Autophagy, a subcellular process for bulk destruction of proteins and organelles in lysosomes, is an essential in vivo process mediating proper vascular function. Because impaired or defective autophagy underlies major phenotypic signatures of vascular disease, there is an urgent need for pharmacological interventions with compounds that stimulate autophagy in the vasculature. In order to fulfill this need, a PhD student (affiliated to the Laboratory of Medicinal Chemistry, Department of Pharmaceutical Sciences) will be recruited to constitute a reliable platform for hit-to-lead optimization of autophagy-inducing drugs and to characterize their mode of action. Moreover, a postdoctoral researcher (affiliated to the Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences) will be hired to initiate the evaluation of autophagy induction in mouse models of vascular disease such as arterial stiffening and atherosclerosis.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: Van Der Veken Pieter

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Morphological studies indicate that the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrosis. Although the role of necrosis in atherosclerosis remains ill-defined, a growing body of evidence suggests that necrotic death stimulates atherogenesis and plaque instability through induction of inflammation and enlargement of a central necrotic core. For a long time, necrosis has been considered as a merely accidental and uncontrolled form of cell death, but recent data suggest that it can also occur in a regulated fashion. Necroptosis is the best characterized form of regulated necrosis and requires receptor interacting protein kinases (RIPKs) as key regulators. However, other examples such as ferroptosis are also emerging. Because regulated necrosis is considered as an important research target to stabilize plaques, the following objectives are defined: (1) inhibition of necroptosis and ferroptosis in atherosclerosis using mice containing catalytically inactive RIPK1, or transgenic mice overexpressing the anti-ferroptosis enzyme GPX4, (2) stabilization of atherosclerotic plaques with potent and selective inhibitors targeting necroptosis or ferroptosis, and (3) identification of the molecular mechanisms modulating regulated necrosis in atherosclerosis. This project may lead to the discovery of novel anti atherosclerosis therapies, and will allow a significant advance in the fundamental understanding of regulated necrosis in atherosclerosis.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido
• Fellow: Puylaert Pauline

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Autophagy is a normal physiological process that maintains intracellular homeostasis by degrading unnecessary or dysfunctional cellular components in lysosomes. This way, autophagy supports cell survival in unfavourable conditions and represents a reparative and life-sustaining process. Impaired autophagy is increasingly recognized as a hallmark of aging and of multiple human pathological conditions, including cardiovascular disease. Moreover, impaired autophagy has been linked with increased arterial stiffness, an independent risk marker of cardiovascular disease. Therefore, inducing autophagy could be a game-changer in the treatment of cardiovascular disease. However the potential of autophagy inducing drugs has not been realized yet due to the absence of potent and selective tool compounds. The current proposal will start from a number of hits identified in a high-throughput screening and will further validate these lead candidates through a series of in vitro and in vivo studies focussing on vascular biology. Using geneticallyengineered mice with cell-type specific autophagy defect, the selectivity of the final lead compound will be demonstrated. Moreover, we aim to establish preclincal proof of concept of autophagy induction as therapeutic strategy for cardiovascular ageing and the development of atherosclerosis.

Researcher(s)

• Promoter: Guns Pieter-Jan
• Co-promoter: Martinet Wim
• Fellow: Neutel Cédric

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Necrosis is a type of cell death characterized by a gain in cell volume, swelling of organelles, rupture of the plasma membrane and subsequent loss of intracellular contents. For a long time, the process has been considered as a merely accidental and uncontrolled form of cell death, but accumulating evidence suggests that it can also occur in a regulated fashion. Necroptosis is the most understood form of regulated necrosis and requires receptor interacting protein (RIP) kinases as key regulators, but also other examples such as ferroptosis are emerging. Morphological studies using transmission electron microscopy indicate that the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrosis. Although the role of necrosis in atherosclerosis remains ill-defined, a growing body of evidence suggests that necrotic death stimulates atherogenesis and plaque instability through induction of inflammation and enlargement of the necrotic core. Therefore, the following objectives are defined in the present research proposal: (1) Identification of potential beneficial effects of macrophage-specific RIP1 gene deletion on atherosclerosis development, and (2) stabilization of atherosclerotic plaques with potent and selective inhibitors targeting RIP1 kinase activity or ferroptosis. The project may contribute to the development of novel (add-on) therapies for stabilization of atherosclerotic plaques.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Augustyns Koen
• Co-promoter: Martinet Wim
• Fellow: Coornaert Isabelle

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Atherosclerotic plaque rupture is the leading cause of acute cardiovascular syndromes and is responsible for 3.9 million deaths in Europe every year. Preventive strategies are greatly needed to reduce the health care burden of cardiovascular disease (CVD). The Mediterranean diet results in a lower CVD risk, with virgin olive oil as its key element. Many of the health-promoting effects are ascribed to the olive polyphenols (OPs) and recently a link with autophagy induction was shown. Autophagy is a cellular housekeeping mechanism and autophagy deficiency is detrimental in the development of CVD. Thus, inducing autophagy is likely to be an effective preventive strategy. OPs were identified as natural autophagy inducers, but further research is needed to define the contribution of this mechanism to their atheroprotective effects. Therefore, we aim to elucidate the role of endothelial cell and vascular smooth muscle cell autophagy in the atheroprotective effects of OPs. The research objectives are divided in 3 work packages: (1) Selection of the most potent autophagy-inducing OP and the most therapeutically effective dose, (2) Investigation of the vasomotor effects of an OP and the role of autophagy and (3) Investigation of the atheroprotective effects of an OP and the role of autophagy. This project will give insight in the mechanism of action of OPs and is an important step towards the implementation of OP nutraceuticals for the prevention of cardiovascular disease.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Roth Lynn

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Atherosclerosis is an inflammatory disorder of the arterial wall leading to myocardial infarction, stroke and peripheral arterial disease. Recently, we published that elastin fragmentation, due to a mutation (C1039G+/-) in the fibrillin-1 (Fbn1) gene, promotes atherogenesis and a highly unstable plaque phenotype in apolipoprotein E deficient (ApoE-/-) mice on a Western-type diet. Interestingly, ApoE-/-Fbn1C1039G+/- mice reveal substantial intraplaque (IP) neovascularization, which is a typical feature of advanced human atherosclerotic plaques, but rarely observed in animal models. Because clinical evidence links IP angiogenesis with progressive and unstable vascular disease, we will investigate whether inhibition of IP neovascularization has a beneficial effect on atherogenesis and plaque stability. Hitherto, blocking VEGF was the primary strategy to reduce neovascularization. Unfortunately, limited efficacy and adverse effects have downsized its success, even when multiple blockers were used simultaneously. Therefore, a fundamentally different approach was needed to re-boost the image of anti-angiogenic therapy. Given that endothelial cells (ECs) rely on glycolysis for up to 85% of their energy demand, targeting the glycolytic pathway represents an attractive new strategy to inhibit neovascularization. Studies in the oncology field already showed that transient and partial inhibition of glycolysis in proliferating ECs inhibits pathological angiogenesis without interfering in the metabolism of healthy cells. Therefore, this project has the following three objectives, each associated to a dedicated work package: (1) Inhibition of glycolytic flux by deletion of a key regulating enzyme in glycolysis (PFKFB3) specifically in ECs. We will examine the effects of PFKFB3 deletion in ECs on atherogenesis and plaque stability using ApoE-/- Fbn1C1039G+/- mice. (2) Pharmacological inhibition of IP angiogenesis in ApoE-/- Fbn1C1039G+/- mice using PFKFB3 inhibitor 3PO or alternative compounds that specifically bind PFKFB3. (3) Development of an imaging tool to evaluate inhibition of IP neovascularization using advanced microscopy techniques. For each work package, several tasks have already been completed, highlighting (i) the feasibility of this DOCPRO1 project and ii) the need for the additional and final year to bring this PhD project to a successful end.

Researcher(s)

• Promoter: Martinet Wim
• Fellow: Perrotta Paola

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

The research program on Molecular mechanisms of cellular DEath and Life decisions in Inflammation, Degeneration and Infection (MODEL-IDI) aims at performing fundamental research on the biology of cell death modalities, cell survival regulation and their consequences on the onset and/or progression of diseases. The program aims at linking the discoveries obtained in vitro on the molecular regulation of cell death and inflammation to their in vivo physiological relevance by making use of chemical tool compounds and experimental models of diseases, such as diabetes type I & II, hepatotoxicity and liver cancer, atherosclerosis and neurodegenerative diseases.

Researcher(s)

• Promoter: Augustyns Koen
• Co-promoter: Martinet Wim

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Three UAntwerp research groups (Medicinal Chemistry, Physiopharmacology, MIPRO) recently joined forces for the discovery and study of autophagy modulators as potential oncology therapeutics. Hitherto, this approach has resulted in a joint patent application and several manuscripts that have either been published or are under preparation. Most attention to date has gone to investigation of UAMC-2526, an Atg4B-targeting autophagy inhibitor that was discovered by the project team. This compound has potent in vivo autophagy blocking properties and significant anti-tumoral potential in an in vivo xenograft mouse model of colorectal cancer. To ensure economical valorization interest for UAMC-2526 and the UAntwerp-patented family of compounds to which it belongs, more basic research is required. The balanced package of medicinal chemistry, in vitro pharmacology and in vivo oncology that is presented here, should provide detailed insight in the potential of UAMC-2526 and its analogues as a potential therapeutic agent. In addition, biopharmaceutically optimized follow-up candidates for UAMC-2526 will be delivered. At the same time, this effort will increase the compounds' attractiveness to external economic valorization partners. Finally, this project will also create critical mass for a preclinical research platform on autophagy research at UAntwerp. This platform will unite chemical and biological capabilities in autophagy research that will be highly instrumental to support research programs, but will also be offered to private partners that require expertise in the domain.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Martinet Wim
• Co-promoter: Peeters Marc
• Co-promoter: Stroobants Sigrid

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

The microenvironment of most solid tumors tends to be significantly more acidic than healthy tissue. Inadequate perfusion, oxygen limitation and cell metabolic changes, are key causative factors for this situation. The acidic pH induces a number of specific genetic, transcriptional and metabolic effects in tumor cells. These are required for survival under increased H+- stress. Evidence is now mounting that these effects also play a major role in tumor progression, invasiveness and the development of multi-resistance to therapy. Two pivotal adaptations related to maintaining intracellular pH homeostasis in an acidic environment, have recently received significant attention: (1) the presence of chronic autophagy in tumors and (2) the overexpression of carbonic anhydrases (CAs), mainly CA IX and CA XII. This project will biopharmaceutically optimize a novel class of specific autophagy inhibitors that target Atg4B. The specific goal of this part of the project is to obtain orally bioavailable and metabolically stable compounds that are fit for in vivo applications. The relevance of these compounds is clear, given the unmet demand for reliable, specific inhibitors in the domain of autophagy. At the same time, the project will evaluate the potential for therapy development of the compounds in the framework of cancer. Finally, the proposal will explore whether a further increase of anti-tumor efficiency can be obtained by combining Atg4B- and CA-inhibitor pharmacophores in a single compound.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Martinet Wim
• Co-promoter: Peeters Marc
• Fellow: Tanc Muhammet

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Necrosis is a type of cell death characterized by a gain in cell volume, swelling of organelles, rupture of the plasma membrane and subsequent loss of intracellular contents. For a long time, the process has been considered as a merely accidental and uncontrolled form of cell death, but accumulating evidence suggests that it can also occur in a regulated fashion. Necroptosis is the most understood form of regulated necrosis and requires receptor interacting protein (RIP) kinases as key regulators, but also other examples such as ferroptosis are emerging. Morphological studies using transmission electron microscopy indicate that the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrosis. Although the role of necrosis in atherosclerosis remains ill-defined, a growing body of evidence suggests that necrotic death stimulates atherogenesis and plaque instability through induction of inflammation and enlargement of the necrotic core. Therefore, the following objectives are defined in the present research proposal: (1) Identification of potential beneficial effects of macrophage-specific RIP1 gene deletion on atherosclerosis development, and (2) stabilization of atherosclerotic plaques with potent and selective inhibitors targeting RIP1 kinase activity or ferroptosis. The project may contribute to the development of novel (add-on) therapies for stabilization of atherosclerotic plaques.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Augustyns Koen
• Co-promoter: Martinet Wim
• Fellow: Coornaert Isabelle

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Despite recent scientific and technological advances, cardiovascular disease remains the leading cause of morbididy and mortality worldwide. Autophagy, a subcellular process for bulk destruction of proteins and organelles in lysosomes, has been implicated in the pathogenesis of atherosclerosis and a wide range of heart pathologies. However, the precise role of autophagy in these contexts remains obscure. In addition, the physiological significance of autophagy in the normal vasculature is largely unknown. Therefore, the following objectives are defined in the present research proposal: (1) study of the effect of autophagy deficiency in smooth muscle cells or endothelial cells on vasomotor function and blood pressure, (2) study of the effect of autophagy deficiency on the progression and stability of atherosclerotic plaques, and (3) prevention of atherosclerotic plaque rupture and downstream complications such as myocardial infarction and sudden death through pharmacological induction of autophagy. This project will give insight whether autophagy is beneficial or detrimental for cardiovascular disease and whether it plays a role in normal vascular function.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Despite recent scientific and technological advances, cardiovascular disease remains the leading cause of morbididy and mortality worldwide. Autophagy, a subcellular process for bulk destruction of proteins and organelles in lysosomes, has been implicated in the pathogenesis of atherosclerosis and a wide range of heart pathologies. However, the precise role of autophagy in these contexts remains obscure. In addition, the physiological significance of autophagy in the normal vasculature is largely unknown. Therefore, the following objectives are defined in the present research proposal: (1) study of the effect of autophagy deficiency in smooth muscle cells or endothelial cells on vasomotor function and blood pressure, (2) study of the effect of autophagy deficiency on the progression and stability of atherosclerotic plaques, and (3) prevention of atherosclerotic plaque rupture and downstream complications such as myocardial infarction and sudden death through pharmacological induction of autophagy. This project will give insight whether autophagy is beneficial or detrimental for cardiovascular disease and whether it plays a role in normal vascular function.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido
• Fellow: De Munck Dorien

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Necrosis is a type of cell death characterized by a gain in cell volume, swelling of organelles, rupture of the plasma membrane and subsequent loss of intracellular contents. For a long time, the process has been considered as a merely accidental and uncontrolled form of cell death, but accumulating evidence suggests that it can also occur in a regulated fashion. Necroptosis is the most understood form of regulated necrosis and requires receptor interacting protein (RIP) kinases as key regulators, but also other examples such as ferroptosis are emerging. Morphological studies using transmission electron microscopy indicate that the vast majority of dying cells in advanced human atherosclerotic plaques undergo necrosis. Although the role of necrosis in atherosclerosis remains ill-defined, a growing body of evidence suggests that necrotic death stimulates atherogenesis and plaque instability through induction of inflammation and enlargement of the necrotic core. Therefore, the following objectives are defined in the present research proposal: (1) Identification of potential beneficial effects of macrophage-specific RIP1 gene deletion on atherosclerosis development, and (2) stabilization of atherosclerotic plaques with potent and selective inhibitors targeting RIP1 kinase activity or ferroptosis. The project may contribute to the development of novel (add-on) therapies for stabilization of atherosclerotic plaques.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: Augustyns Koen
• Co-promoter: De Meyer Guido
• Fellow: Coornaert Isabelle

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Despite recent scientific and technological advances, cardiovascular disease remains the leading cause of morbididy and mortality worldwide. Autophagy, a subcellular process for bulk destruction of proteins and organelles in lysosomes, has been implicated in the pathogenesis of atherosclerosis and a wide range of heart pathologies. However, the precise role of autophagy in these contexts remains obscure. In addition, the physiological significance of autophagy in the normal vasculature is largely unknown. Therefore, the following objectives are defined in the present research proposal: (1) study of the effect of autophagy deficiency in smooth muscle cells or endothelial cells on vasomotor function and blood pressure, (2) study of the effect of autophagy deficiency on the progression and stability of atherosclerotic plaques, and (3) prevention of atherosclerotic plaque rupture and downstream complications such as myocardial infarction and sudden death through pharmacological induction of autophagy. This project will give insight whether autophagy is beneficial or detrimental for cardiovascular disease and whether it plays a role in normal vascular function.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido
• Fellow: De Munck Dorien

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

The mission of MoGlyNet is to define a joint doctorate educational training model in Drug Discovery and Development where Academia and Industry join their forces for:- creating a common platform of knowledge and language for early stage researchers (ESR) working in the Drug Discovery and Development area aiming to convey complementary pharma-skills- exploiting this platform to train a new generation of cutting-edge researchers and professionals highly attractive for employment by the European Pharma-industry- establishing structures for long-term cooperation, strengthening the relationships among the leading Universities and Pharma-enterprises and to continuously develop the research training platform that European industry relies on.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Autophagy is a reparative, life-sustaining process that has been associated with a plethora of different pathological conditions. Although some histological studies have demonstrated that autophagy occurs in advanced atherosclerotic plaques, the role of autophagy in atherogenesis, plaque stability and vasomotor function is largely unknown. In the present research proposal, we aim to perform a detailed investigation of the role of autophagy in atherosclerosis and in normal vascular function.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Rupture of atherosclerotic plaques remains the main cause of acute cardiovascular syndromes and death. The need for novel plaque stabilizing therapies is high, but adequate animal models of plaque rupture are lacking. We recently discovered that apolipoprotein E knock-out (ApoE-/-) mice with a heterozygous mutation (C1039G+/-) in the fibrillin-1 (Fbn1) gene show elastin fragmentation and arterial stiffness which leads to acute plaque rupture, myocardial infarction, stroke and sudden death. Although elastin fragmentation seems to trigger plaque rupture in ApoE-/- Fbn1C1039G+/- mice, there is currently insufficient evidence that supports this hypothesis. Therefore, the present research proposal aims to use ApoE-/-Abcc6-/- mice representing another mouse model of elastin degradation, yet via an alternative mechanism that involves progressive mineralization of the vessel wall. After confirmation of elastin fragmentation in ApoE-/-Abcc6-/- mice, the key objectives of the project are: 1) Characterization of ApoE-/-Abcc6-/- mice for atherosclerotic plaque development and rupture. 2) Validation of this mouse model for plaque rupture with established plaque stabilizing drugs (statins). 3) Study of the effects of everolimus as a novel potential plaque stabilizing therapy. Overall, this research proposal could provide better insights in the mechanisms of plaque rupture, and would allow quick evaluation of potential plaque stabilizing therapies on genuine clinical end points of plaque rupture in mice.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Keulenaer Gilles
• Fellow: Van der Veken Bieke

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

This project aims to study the following topics: 1) Role of autophagy in plaque formation and critical regression by everolimus using autophagydeficient mice 2) Cholesterol efflux in macrophage-derived foam cells or atherosclerotic mice after everolimus administration 3) Effect of everolimus on intraplaque neovascularization and rupture in a unique mouse model showing substantial sprouting of neovessels in the plaque as well as acute plaque rupture Overall, this work could provide more insights in everolimus-induced plaque regression, and may contribute to a more purposeful treatment of unstable plaques.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: Bult Hidde
• Co-promoter: Schrijvers Dorien

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Atherosclerosis is an inflammatory disease which is characterized by the formation of plaques in the arterial wall. Destabilization of atherosclerotic plaques causes plaque rupture which can lead to severe complications such as myocardial infarction and stroke. Atherosclerotic plaques become unstable due to intensive cell death of macrophages, smooth muscle cells and endothelial cells. We will therefore inhibit the three main forms of cell death, namely apoptosis, autophagy and necrosis in mice via a genetic and if possible, a pharmacological approach. In this way, we hope to improve plaque stability and contribute to the development of novel plaque stabilizing therapies.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: Schrijvers Dorien
• Fellow: Grootaert Mandy

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Acute cardiovascular syndromes (e.g. myocardial infarction and stroke) are a major cause of morbidity and mortality in industrialized countries. They result from rupture and subsequent thrombosis of an atherosclerotic plaque that has built up in the wall of large and middle-sized arteries. Chronic inflammation, mediated by dendritic cells (DCs) drives the development of atherosclerosis. DCs are present in healthy arteries in areas predisposed to atherosclerotic plaque formation, and accumulate within plaques where they can be localized in close vicinity to T cells. Recent work has revealed important functions of DCs in regulating inflammatory and immune mechanisms in atherogenesis. In addition to antigen presentation to T-cells with subsequent activation, DCs themselves will secrete inflammatory cytokines (e.g. IL-12), further exacerbating atherosclerosis. Because of their unique properties (capable of inducing either immune responses or immune tolerance), DCs can be harnessed to suppress unwanted responses, in the form of vaccines. Vaccination strategies using DCs are currently being explored in various diseases. In fact, the approval of Provenge® (the first "DC vaccine" for prostate cancer) by the FDA in 2010 has paved the way for further development of DC vaccines. Our central hypothesis is that a vaccine-based approach to manage atherosclerotic cardiovascular disease is a potentially viable strategy. In fact, the first proof of concept that this approach could be very useful in combatting cardiovascular disease came very recently from the group of Goran Hansson. Treatment of mice with in vitro generated tolerogenic DCs attenuated atherosclerotic plaque development. However, these DCs have an unstable phenotype. Therefore, in this project we aim to (1) identify biomarkers for plaque DCs for targeted immunotherapy, (2) generate stable, tolerogenic DCs using RNA interference to suppress autologous T-cell activation and (3) study the effects of siRNA mediated DC targeted IL-12 silencing on atherosclerotic plaque progression and stability in mice. This research program is part of a global research effort to develop new therapeutic approaches for atherosclerotic plaque stabilization. Specifically, the current program aims to elucidate whether or not modulation of immune responses can stabilize atherosclerotic plaques.

Researcher(s)

• Promoter: Schrijvers Dorien
• Co-promoter: Cools Nathalie
• Co-promoter: Martinet Wim
• Fellow: Rombouts Miche

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Rupture of atherosclerotic plaques remains the main cause of acute cardiovascular syndromes and death. The need for novel plaque stabilising therapies is high, but adequate animal models are lacking. We recently discovered that ApoE-/- mice with a disturbed fibrillin production (ApoE-/-/C1039G+/- mice) fed a Western-type diet develop more unstable plaques as compared to ApoE-/- mice. Interestingly, acute plaque rupture and death occurred very frequently: 50% of the ApoE-/-/C1039G+/- mice died suddenly within 20 to 52 weeks, most likely due to cerebral embolism, whereas all ApoE-/- mice survived. Further optimisation and characterisation of this model could provide better insights in the mechanisms of plaque rupture, and also give for the first time the opportunity to evaluate potential plaque stabilising therapies on genuine clinical end points of plaque rupture (embolism, stroke and/or death) in mice. The aims of the project are: 1) Further optimisation and characterisation of the model. We will investigate whether additional destabilising stimuli can augment and speed up the incidence of plaque rupture, which is important for the evaluation of plaque stabilising therapies. 2) Validation of this model with established plaque stabilising drugs such as statins. 3) Study of the effects of novel potential plaque stabilising therapies (phytosterols, NO-donor).

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Roth Lynn

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this project, we aim to perform a detailed investigation of the role of autophagy in atherosclerosis and in normal vascular function: (1) Study of the effect of pharmacological induction of autophagy on atherogenesis and plaque stability (molecular pathways of autophagy induction, effect on plaque formation and composition), (2) Study of the effect of autophagy deficiency on the progression and stability of atherosclerotic plaques, (3) Study of the effect of autophagy deficiency or induction on vasomotor function. This project will give insight whether autophagy is beneficial or detrimental for the development and stability of atherosclerotic plaques and whether it plays a role in normal vascular function.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

The first aim of this project is to obtain better insight into the pro-inflammatory responses that might occur after druginduced macrophage death in atherosclerotic plaques. A second aim is to prevent or inhibit enlargement of the necrotic core by crossbreeding RIP3-/- mice, deficient in necrotic signaling, with atherosclerosis-prone apoE-/- mice. Alternatively, necrosis will be inhibited via administration of necrosis inhibitors, both in vitro and in vivo. Overall, the project may contribute to a more purposeful treatment of unstable plaques.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Van der Donckt Carole

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this study, we will investigate the role of autophagy (a cell survival and death pathway) and adiponectin (an endogenous hormone produced by fat cells) in a protective post-myocardial infarction reperfusion therapy called postconditioning. Adiponectin has protective myocardial effects that limit lethal reperfusion injury. However, patients with central obesity have low plasma levels of adiponectin, which may confound the cardioprotective properties of postconditioning.

Researcher(s)

• Promoter: Vrints Christiaan
• Co-promoter: Claeys Marc
• Co-promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Co-promoter: Timmermans Jean-Pierre

Research team(s)

Project type(s)

• Research Project

Abstract

This proposal aims at developing inhibitors of cysteine protease Atg4B, a prime regulator of autophagy, as innovative tools for selective autophagy blocking. Additionally, inhibitor-derived probe molecules will be prepared, enabling further study of Atg4B's role in cellular physiology and in the initiation and propagation of autophagic processes.

Researcher(s)

• Promoter: Van Der Veken Pieter
• Co-promoter: Augustyns Koen
• Co-promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

The aims of the project are: 1) Further optimisation and characterisation of the model. We will investigate whether additional destabilising stimuli can augment and speed up the incidence of plaque rupture, which is important for the evaluation of plaque stabilising therapies. 2) Validation of this model with established plaque stabilising drugs such as statins. 3) Study of the effects of novel potential plaque stabilising therapies (phytosterols, NO-donor).

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Bult Hidde
• Co-promoter: Martinet Wim
• Co-promoter: Verhoye Marleen

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Martinet Wim
• Fellow: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Michiels Cédéric

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Rupture of atherosclerotic plaques remains the main cause of acute cardiovascular syndromes and death. The need for novel plaque stabilising therapies is high, but adequate animal models are lacking. We recently discovered that ApoE-/- mice with a disturbed fibrillin production (ApoE-/-/C1039G+/- mice) fed a Western-type diet develop more unstable plaques as compared to ApoE-/- mice. Interestingly, acute plaque rupture and death occurred very frequently: 50% of the ApoE-/-/C1039G+/- mice died suddenly within 20 to 52 weeks, most likely due to cerebral embolism, whereas all ApoE-/- mice survived. Further optimisation and characterisation of this model could provide better insights in the mechanisms of plaque rupture, and also give for the first time the opportunity to evaluate potential plaque stabilising therapies on genuine clinical end points of plaque rupture (embolism, stroke and/or death) in mice. The aims of the project are: 1) Further optimisation and characterisation of the model. We will investigate whether additional destabilising stimuli can augment and speed up the incidence of plaque rupture, which is important for the evaluation of plaque stabilising therapies. 2) Validation of this model with established plaque stabilising drugs such as statins. 3) Study of the effects of novel potential plaque stabilising therapies (phytosterols, NO-donor).

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Roth Lynn

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Van der Donckt Carole

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Rupture of unstable atherosclerotic plaques can lead to important atherothrombotic complications, such as myocardial infarction. Therefore, stabilisation of plaques is an important pharmacological target. In the destabilisation process macrophages play a key role, whereas smooth muscle cells contribute to plaque stability. The first aim of this project is to selectively induce autophagy of macrophages in atherosclerotic plaques by means of drugs. The second aim is to study the implications and possible complications of induction of macrophage autophagy in atherosclerotic plaques and the comparison with induction of other types of cell death (apoptosis, necrosis). In the third aim, we will investigate new drug targets that can affect cell death of macrophages. In the fourth aim we wish to develop drug eluting stents to induce selective induction of macrophage cell death in atherosclerotic plaques.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: De Meyer Inge

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Macrophages play a central role in atherosclerotic plaque destabilization, leading to acute coronary syndromes and sudden death. Removal of macrophages from plaques via pharmacological therapy may therefore represent a promising approach to stabilise vulnerable, rupture-prone lesions. In this project, we will evaluate strategies and unravel the mechanisms to deplete macrophages in atherosclerotic plaques via drug-induced cell death without affecting smooth muscle cell content.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this project, we would like to develop additional strategies for selective clearance of macrophages in atherosclerotic plaques. Furthermore, the influence of macrophage cdl death on the stability of plaques will be investigated. It should be noted that selective clearance of macrophages in plaques is a new concept in cardiovascular research that may contribute to a more purposeful treatment of unstable plaques.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Given the strong association between the development of the obese/metabolic phenotype and atherosclerosis, it is essential to fully characterize the ApoE-/-TG2-/- mice at a morphological level. Furthermore, the impact of deficient phagocytosis of apoptotic cells on the development and composition of atherosclerotic plaques in ApoE-/-TG2-/- mice will be investigated. Finally, the development and progression of the obese phenotype will be studied.

Researcher(s)

• Promoter: Herman Arnold
• Promoter: Martinet Wim
• Co-promoter: Herman Arnold
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this project, we would like to develop additional strategies for selective depletion of macrophages in atherosclerotic plaques. On the other hand, the influence of macrophage cell death on the stability of plaques will be investigated. It should be noted that selective depletion of macrophages from plaques is a new concept in cardiovascular research that may contribute to a more purposeful treatment of unstable plaques.

Researcher(s)

• Promoter: Bult Hidde
• Promoter: Herman Arnold
• Fellow: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Rupture of unstable atherosclerotic plaques can lead to important atherothrombotic complications, such as myocardial infarction. Therefore, stabilisation of plaques is an important pharmacological target. In the destabilisation process macrophages play a key role, whereas smooth muscle cells contribute to plaque stability. The first aim of this project is to selectively induce autophagy of macrophages in atherosclerotic plaques by means of drugs. The second aim is to study the implications and possible complications of induction of macrophage autophagy in atherosclerotic plaques and the comparison with induction of other types of cell death (apoptosis, necrosis). In the third aim, we will investigate new drug targets that can affect cell death of macrophages. In the fourth aim we wish to develop drug eluting stents to induce selective induction of macrophage cell death in atherosclerotic plaques.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: De Meyer Inge

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

The development of strategies for selective depletion of macrophages in atherosclerotic plaques via drug-induced cell death represents a new concept in cardiovascular research that may contribute to plaque stabilization and the prevention of coronary syndromes or sudden death

Researcher(s)

• Promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In view of the alterations in SMC function in young plaque-free apoE-1- mice, we wish to test the hypothesis that SMCs promote atherogenesis at lesion-prone site. The objectives of this proposal are: 1) To document possible differences in gene expression in SMCs at atherosclerosis-prone (AP) and atherosclerosis­ resistant (AR) locations. 2) To investigate putative mechanisms causing differential gene expression. 3) To study the impact of anti-atherogenic interventions on the expression profile. 4) To test whether those genes affect SMC function.

Researcher(s)

• Promoter: Bult Hidde
• Co-promoter: Martinet Wim

Research team(s)

Project type(s)

• Research Project

Abstract

The availability of a fast and adequate animal model of unstable plaques, including the induction of plaque microvessels, may lead to a better understanding of the pathophysiological mechanisms of plaque instability and rupture and may constitute the foundation of pharmacotherapy of unstable plaques. In this project, we will investigate whether microvessels can be induced in experimental atherosclerotic plaques and whether the affect growth, composition and stability of plaques. Furthermore, the effect of drugs on microvessels and plaque stability will be studied.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this study, microvessels will be induced in atherosclerotic plaques from rabbits. The influence of microvessels on growth, composition and stability of the plaque will be determined. On the other hand, the effect of pharmaca (statins, nitrogen monoxide donors) on microvessel development and plaque stability will be examined. In parallel, we also aim to get a better insight into the pathophysiological mechanisms underlying plaque instability and rupture as well as the development and validation of new endpoints for the evaluation of plaque stability.

Researcher(s)

• Promoter: Martinet Wim
• Co-promoter: De Meyer Guido

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

Atherosclerosis is a chronic inflammatory disease of the arterial intima characterized by the formation of an atherosclerotic plaque. In recent years, our research group has shown that cell death could be a potential cause of plaque destabilization. In this project, various types of cell death (apoptosis, necrosis and autophagy) will be studied simultaneously in smooth muscle cell cultures as well as in monocytes/macrophages by addition of specific stimuli. To detect the different types of cell death in cell culture, several methods will be developed in parallel. By using these methods, we will investigate which forms of cell death can be induced in cultivated macrophages and smooth muscle cells with atherosclerosis-associated, cytotoxic components such as oxysterols and aggregated LDL. In contrast to apoptotic cell death, few human genes or gene products that are involved in autophagy are known. Accordingly, microarray and/or proteomics techniques (Western array or 2D-gel electrophoresis) will be used to find potential markers for autophagy in cell culture. Once suitable biomarkers are found and detection of the various forms of cell death is possible, these techniques will be applied on human and experimental plaques to localize cell death in the tissue itself. Finally, it should be noted that the study of therapeutic effects of pharmaca or specific diets on the occurrence of non-apoptotic cell death in atherosclerotic plaques is a major part of this project.

Researcher(s)

• Promoter: Herman Arnold
• Fellow: Martinet Wim

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

In this project we will investigate the role of ß-amyloid peptide (Aß) and its precursor (APP) in atherosclerosis. Hitherto, APP has only been studied in brain tissue in Alzheimer's disease. A possible source for APP in atherosclerotic plaques are platelets. We will study 1) the localisation and distribution of APP and A? in human atherosclerotic plaques and in a model of atherosclerosis; 2) the association with inducible nitric oxide synthase (iNOS); 3) the influence of cholesterol and lipids on ?-amyloid deposition in models with APP overexpression; 4) the interaction between APP processing and iNOS expression; 5) the effect of Aß on the endothelial cell function of blood vessels. These data could lead to a better understanding of the role of processing of APP, derived from platelets, in the destabilisation and rupture of an atherosclerotic plaque and on the endothelial cell function of blood vessels.

Researcher(s)

• Promoter: De Meyer Guido
• Co-promoter: Martinet Wim
• Fellow: Jans Dominique

Research team(s)

• Physiopharmacology (PHYSPHAR)

Project type(s)

• Research Project

Abstract

To study the role of DNA damage/repair in the progression of human and experimental atherosclerosis, macrophages and smooth muscle cells from plaque tissue will be isolated via laser capture microdissection. and further analysed at the molecular level by means of multiplex P CR, Western blotting, Comet assay and microarray technology.

Researcher(s)

• Promoter: Martinet Wim

Research team(s)

Project type(s)

• Research Project