Pharmaceutical, Biomedical and Veterinary Sciences

Judith van Rooij

• 2 June 2026, 4pm - 6pm
• Promotiezaal, Q.002 (CDE)
• Promoters: Marleen Verhoye, Daniele Bertoglio

Abstract

Alzheimer’s disease (AD) is increasingly recognized as a multifactorial disorder in which early metabolic dysfunction, neuroinflammation, and mitochondrial impairment interact with classical amyloid and tau pathology. These processes disrupt neuronal–glial and neurovascular homeostasis, leading to large-scale network alterations, neuronal loss, and cognitive decline. Preclinical models are essential to investigate early disease mechanisms and to test interventions targeting these processes. Caloric restriction (CR) and its mimetic resveratrol (Rsv) may attenuate early metabolic and inflammatory dysfunction, potentially delaying AD onset. Using MRI-based approaches, this thesis examined the short- and long-term effects of CR and Rsv on brain network activity, cerebrovascular function, and cognition in wild-type (WT) and TgF344-AD rats.

Short-term (1 month) interventions in healthy rats revealed sex-specific effects on brain functional connectivity (FC). Both CR and Rsv reduced FC in females, particularly between subcortical, hippocampal, and cortical networks. Rsv additionally decreased connectivity within hippocampal networks and between several large-scale networks, effects not observed with CR, highlighting distinct intervention profiles.

In WT and Tg rats, both short- and long-term interventions showed that CR consistently reduced FC across sexes, whereas short-term Rsv primarily affected females. Disease progression was characterized by early hyperconnectivity at 4 months followed by hypoconnectivity at 11 months, with sex-dependent patterns. Co-activation pattern analysis confirmed dynamic regional alterations in activation over time. Long-term CR modestly improved spatial memory in male rats and induced region- and sex-specific changes in amyloid burden and neuroinflammation, including reduced microglial activation. However, overall cognitive improvements were limited, leaving the functional relevance of these changes uncertain.

Cerebrovascular measurements further demonstrated complex and sex-specific responses. At 4 months, Tg males showed reduced cerebral blood flow (CBF), which was further decreased by short-term CR, while Rsv increased CBF in female Tg rats under hypercapnic conditions. At 11 months, long-term Rsv restored CBF deficits in male Tg rats, whereas CR reduced cerebrovascular reactivity (CVR), particularly in females. These findings suggest that increases in CBF or reductions in CVR may not necessarily be beneficial in the context of AD.

In conclusion, CR and Rsv exert modest, sex-specific effects on brain and vascular function. Although CR produced more pronounced effects than Rsv, its long-term impact—particularly reductions in FC and CVR—may create conditions that compromise neuronal function. These results underscore the complexity of targeting metabolic pathways in AD and highlight the importance of considering sex differences in therapeutic strategies.

Joëlle van Rijswijk

• 22 May 2026, 5pm - 7pm
• Auditorium O1 (CDE)
• Promoters: Marleen Verhoye, Mohit Adhikari

Mathijs van der Lei

• 12 May 2026, 5pm - 7pm
• Auditorium O5 (CDE)
• Promoter: Frank Kooy

Abstract

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and a major genetic contributor to autism spectrum disorder, affecting approximately 1 in 4000–7000 males and 1 in 6000–11000 females. It is caused by a CGG repeat expansion (>200 repeats) in the FMR1 gene, leading to transcriptional silencing and loss of fragile X messenger ribonucleoprotein (FMRP), an RNA-binding protein that regulates RNA transport, protein synthesis and synaptic plasticity.

The first part of this thesis investigates the hypothesis that GABAergic dysfunction is a central and mechanistic driver of neurodevelopmental disorders, including FXS. In Fmr1 KO mice, specific subunits of the GABA_A receptor are affected in a brain region and age-dependent manner, reflecting a complex reorganization of inhibitory signaling rather than a simple loss of inhibition. Using conditional knockout mouse models, we demonstrate that deletion of Fmr1 in parvalbumin interneurons is sufficient to induce anxiety-like behavior, social deficits and abnormal protein synthesis, whereas deletion in somatostatin interneurons results in only minor effects. In addition, the contribution of impaired GABA synthesis is supported by the identification of individuals with biallelic GAD2 variants, as well as by the presence of behavioral abnormalities in the corresponding mouse model.

The second part of this thesis focuses on improving the translational relevance of preclinical research. Longitudinal multi-electrode array recordings reveal delayed maturation and persistent hyperexcitability in Fmr1 KO neuronal cultures. To overcome the limitations of traditional behavioral assays, we developed the Live Mouse Tracker (LMT)–MouseKing platform for automated, in-depth, group-based phenotyping. This system enables continuous monitoring of socially housed mice and uncovers a robust behavioral signature in Fmr1 KO mice. This signature is characterized by increased isolated activity, fragmented social interactions and reduced sustained social contact, closely mirroring the human FXS phenotype. Using this framework, five candidate therapeutics were evaluated. While behavioral modulation was frequently observed, genotype-specific rescue was rare, suggesting that many compounds act on broadly preserved pathways. Notably, the GABA_A receptor agonist gaboxadol uniquely induced a selective, dose-dependent behavioral improvement. Together, the findings of this thesis identify GABAergic dysfunction as a core mechanism in FXS and establish a more predictive, translational framework to help bridge the gap between preclinical research and successful clinical therapies.

Rokaya Abdel-Naiem Ahmad

• 22 April 2026, 10am - 12am
• Promotiezaal, Q.002 (CDE)
• Promoter: Guy Caljon

Abstract

Visceral leishmaniasis (VL), caused by Leishmania parasites, is one of the most neglected tropical diseases, endemic in nearly 90 countries worldwide. Control and elimination programs rely mainly on chemotherapeutic agents, as no vaccine is available. Antileishmanial drug discovery has witnessed significant progress over the last two decades, empowered by advanced functional genomic technologies. However, the high attrition rate of compounds toward clinical development and the limited understanding of Leishmania cell biology emphasize the need to explore new target-validated and mechanistically informed antileishmanial leads. To meet the "Know your Target" principle of drug discovery, we engineered Leishmania lines to investigate the mode of action of new antileishmanial compounds. In Leishmania, like any eukaryotic cell, spatiotemporal distribution of molecules across subcellular organelles is coordinated by endosomal trafficking, while the shuttling of molecules between the cytoplasm and nucleus relies on active nucleocytoplasmic transport mechanisms. This central role of intracellular trafficking pathways provides a mechanistic framework to identify and validate druggable processes.

First, through elaborate mode-of-action studies of antileishmanial aminopyrazoles, we discovered that disrupting the assembly of endosomes is a druggable pathway. Mut-Seq and CRISPR-Cas9 gene editing have independently confirmed an association between aminopyrazole resistance and multiple independent heterozygous mutations in LINF_180011100, encoding a putative endosomal FYVE Zn-finger protein. Next, genetic fusion with an N-terminal green fluorescent protein tag and partial colocalization with a C-terminal mCherry-tagged small GTPase Rab5 demonstrated that the functional protein primarily localizes in endocytic vesicles. In situ target engagement assays confirmed a selective effect of aminopyrazoles and its abrogation by introducing a resistance-conferring mutation. Furthermore, a direct interaction between the aminopyrazole lead and the recombinantly produced LINF_180011100 FYVE Zn-finger domain was demonstrated through a biophysical assay.

Our second initiative was to visualize and target nucleocytoplasmic protein transport, which is tightly coordinated by nuclear pore complexes, transport receptors, and the Ran GTPase. We engineered L. infantum to express mCherry fused to a nuclear localization signal, creating a cell-based system to visualize perturbations in nuclear protein transport. Confocal fluorescence microscopy confirmed a nuclear mCherry signal, and a dose-dependent inhibition of nuclear sequestration using the importin-β inhibitor importazole resulting in parasitic cell death. Other lead compounds with different modes of action (MoA) exerted antiparasitic activity independent of nucleocytoplasmic transport impairment, which confirms the assay selectivity.

Collectively, our transgenic lines validate the mode of action of aminopyrazole and importazole and provide valuable tools to study intracellular molecule trafficking in Leishmania and support target-driven drug discovery initiatives.

Leonardo Ricciardi

• 16 March 2026, 10:30 am - 12:30 am
• Promotiezaal, Q.002 (CDE)
• Promoters: Marleen Verhoye, Peter Ponsaerts

Abstract

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system (CNS) with complex and heterogeneous pathology. Its pathophysiological mechanisms remain incompletely understood, limiting the development of curative therapies. Current treatments are primarily disease-modifying approaches that target inflammatory and immunomodulatory pathways, but they do not reverse myelin loss or axonal degeneration. Similarly, available preclinical models cannot fully replicate MS complexity. To address these limitations, the PMSMatTrain consortium was established with a particular focus on progressive MS (PMS), aiming to develop and validate a biomaterial-based device for local delivery of selected therapeutics to cortical PMS lesions in rodents.

The first experimental part of the thesis investigates ‘A Proliferation Inducing Ligand, (APRIL) as a potential CNS therapeutic on the well-established cuprizone (CPZ) model of inflammation and demyelination. APRIL, a member of the tumour necrosis factor (TNF) superfamily, has been implicated in immune homeostasis and neuronal survival in the CNS, but its therapeutic potential in acute neuroinflammatory and neurodegenerative settings has only partially explored. Using adeno-associated virus (AAV)-mediated gene delivery, APRIL was expressed in cortical neurons, and its effects were assessed in CPZ-treated mice via in vivo MRI combined with post-mortem immunohistochemistry (IHC), transcriptomics, and proteomics. This work showed that APRIL secretion can counteract microglial recruitment and demyelination, particularly in the corpus callosum. The integrated transcriptome–proteome analysis demonstrated a positive influence in the cortical area as well, and further identified candidate pathways that help clarify APRIL’s mode of action and support its therapeutic potential in acute neuroinflammatory conditions of the CNS.

In the second experimental part, the PMSMatTrain-developed transcranial delivery device was validated in vivo as a minimally invasive approach to deliver small molecules into the cortex. This system, placed subcutaneously in contact with the skull, combines a silicone dome and semipermeable membrane with specific hyaluronic acid-based hydrogels to enable time-controlled administration through the intact skull. Its efficacy was validated in a proof-of-concept study, using manganese chloride (MnCl₂) as the delivery molecule, and Manganese Enhanced MRI (MEMRI) for the non-invasive monitoring of its cerebral distribution, confirming localised and temporally controlled delivery.

Together, these studies evaluate two complementary research directions that, converging towards the same goal, provide a basis for future strategies aimed at targeted, non-invasive treatment of CNS lesions in MS and potentially other disorders such as stroke and spinal cord injury.

Margot Merlot 

• 22 January 2026, 4pm - 6pm
• Auditorium O1 (CDE)
• Promoters: Guy Caljon, Louis Maes

Abstract

Coccidiosis in chickens and turkeys is caused by various closely related Eimeria species. The infection is transmitted through the fecal-oral route and may lead to large outbreaks that are difficult to mitigate, hence leading to considerable economic losses. The current standard in-feed use of anticoccidials suffers from disadvantages such as increasing drug-resistance, residues in food for human consumption, and legislative pressure to reduce antimicrobial use. The alternative control method is based on the use of multivalent (attenuated) vaccines for which the EU-regulatory authorities require stringent quality criteria for species composition and viability, overall immunogenicity, and vaccine stability. Unfortunately, these data are currently only obtained in expensive and time-consuming in vivo immunization and challenge experiments. In an attempt to overcome the need for these in vivo experiments, this thesis focused on the development of novel in vitro laboratory methodologies by using a combination of flow cytometry and molecular methods for oocyst speciation and viability assessment to better define vaccine composition and batch release characteristics.

To enable quantitation of species-specific viability of oocysts in a multivalent vaccine, permeabilization of the notoriously impermeable oocyst wall was required, which was achieved by developing a detergent-enhanced oocyst viability staining technique. As oocysts of poultry Eimeria species are genetically and morphologically very similar, hereby complicating straightforward species identification, flow cytometric sorting in combination with innovative digital PCR technology using Sequence Characterized Amplified Region (SCAR) primers was implemented. Species quantitation was further refined by applying correction factors that account for DNA extraction efficiency, PCR efficiency and SCAR copy numbers in chicken and turkey Eimeria species. The resulting assay was extensively validated for its intended use as a batch release test and was shown to be applicable across multiple stages of vaccine production, including shelf-life determination and vaccine formulation optimization.

In summary, the PhD thesis describes the development and validation of a novel in vitro laboratory method to quickly determine the species-specific volumetric viability during vaccine development and in the final multivalent coccidiosis vaccine product, providing a novel way to perform batch release testing without the need of animal testing. A provisional patent application of the developed technique has been filed (No. PCT/US2025/032408).

Elizabeth Tabitha Abbew 

• 8 January 2026, 4pm - 6pm
• Aula Janssens (ITG)
• Promoters: Leen Rigouts, Lut Lynen, Dorcas Obiry-Yeboah 

Abstract

Nontuberculous mycobacteria (NTM) are increasingly detected in tuberculosis (TB)-endemic regions, yet their clinical significance remains poorly defined. In sub-Saharan Africa (SSA), limited diagnostic capacity and absence of guidelines contribute to uncertainty in patient management.

This PhD research combined (i) a systematic scoping review of NTM in SSA, (ii) a retrospective laboratory analysis of 2,492 sputum samples in Ghana (2012–2021), (iii) a retrospective cohort of 380 MDR/RR-TB patients in Ghana (2018–2021), and (iv) three prospective cohort studies involving 9,981 symptomatic individuals in Ghana, Nigeria, and Niger. Standard mycobacterial culture, MPT64 antigen testing, line probe assays, and sequencing were used for species identification. Clinical and radiological data were analysed against international ATS/IDSA/ERS/ESCMID criteria for NTM pulmonary disease (NTM-PD).

The scoping review highlighted major gaps: most SSA studies did not apply international diagnostic criteria, species-level identification was rare, and MPT64 antigen misclassified Mycobacterium tuberculosis complex (MTBc) as NTM.

In Ghana, retrospective laboratory analysis showed 33.7% culture positivity. Initially, 30.6% were presumed NTM, but only 53 isolates (23.6%) were confirmed after molecular speciation, reducing the prevalence to 2%. M. intracellulare (66%) predominated, while 18 MTBc isolates, including M. africanum, were misclassified as NTM by MPT64. Four patients fulfilled NTM-PD criteria, all previously treated as RR-TB.

Among 380 MDR/RR-TB patients, 7.1% had NTM isolated, mainly M. intracellulare and M. fortuitum. Treatment success was 67.9%, higher with all-oral bedaquiline regimens (71.4%) compared to injectable-containing regimens (60.3%). HIV was associated with unfavourable outcomes (aOR 1.80, 95% CI 1.05–3.11), while NTM isolation itself was not. Geographic variation showed higher odds of NTM isolation in Eastern (aOR 15.68) and Brong Ahafo regions (aOR 4.74).

In the prospective cohorts, 99/938 (10.6%) had NTM isolated. Predominant species were M. intracellulare (34.3%), M. fortuitum (16.2%), and M. abscessus (10.1%). Among patients with ≥2 sputum samples, 15 (30.6%) met NTM-PD criteria, with 20% mortality. Unique isolates such as M. palustre were detected only by sequencing, reflecting diagnostic limitations of commercial assays.

This thesis demonstrates that although NTM are frequently isolated among presumed TB patients in West Africa, their presence did not adversely affect MDR/RR-TB treatment outcomes in Ghana, while their clinical significance remains challenging to determine due to limited repeated culture data from SSA. These findings underscore the need to strengthen laboratory capacity for species-level identification, integrate molecular diagnostics into routine algorithms, and develop regional clinical guidelines for the diagnosis and management of NTM-PD, while systematically excluding TB