bioRxiv Science⌕ Search

Biology subjects

Venter, K.

Publications and source records attributed to Venter, K..

2 recordsLinked to original sources

The C3HeB/FeJ Kramnik mouse as a model to investigate the efficacy of therapeutic tuberculosis interventions

Tuberculosis (TB) remains a formidable global health challenge, classified as the leading infectious disease killer, driven by the increasing prevalence of multidrug-resistant Mycobacterium tuberculosis strains. This persistent threat not only overwhelms public health infrastructures but also deepens socio-economic inequalities worldwide, underscoring the urgent need for novel therapeutic strategies. The C3HeB/FeJ Kramnik mouse model, frequently used for its capacity to mimic human-like granulomatous lesions, has emerged as a pivotal tool in TB research. However, despite its advantages, the model has limitations, particularly in terms of macrophage pathology and restricted B-cell activity, which pose significant hurdles for translating preclinical findings into human applications. By developing models that better reflect human immune responses, the translation of findings into clinical applications may be improved, ultimately leading to more effective TB treatments and vaccines. This study aims to evaluate the Kramnik model by investigating the efficacy of a novel Pheroid(R) formulation containing traditional TB therapeutics in the C3HeB/FeJ Kramnik mouse model. The potential and limitations inherent to the Kramnik model are explored and the need for complementary genomic analyses, such as sequencing SP110 and SP140, to elucidate the susceptibility linked to the SST1 locus is illustrated. In addition, this article attempts to serve as a critical evaluation of the inherent limitations of current animal models like the Kramnik model, with the aim of paving the way for more accurate and reliable translational research in the fight against TB.

microbiology↗

Delineation of the pathogenic presynaptic mechanisms of synaptotagmin-1 variants

Missense variants in the presynaptic calcium sensor synaptotagmin-1 (SYT1) are associated with an autosomal dominant neurodevelopmental disorder (NDD). These cause dominant-negative impairment of evoked neurotransmitter release in a mutation-specific manner; however, whether NDD-associated variants also perturb the auxiliary functions of SYT1 remains unknown. We investigated whether the expression of SYT1 variants in cultured hippocampal neurons altered either action potential-independent spontaneous synaptic vesicle exocytosis or synaptic vesicle endocytosis. SYT1 variants did not induce dominant-negative impairment of either process, confirming that defective evoked exocytosis is the major pathogenic mechanism of SYT1-associated NDD. To examine the differential impacts of human variants on evoked exocytosis, both NDD-associated and strategic mutations were used to explore the functional importance of two distinct Ca2+-binding residues in the C2B domain. We show that both the nature of the amino acid change and the specific residues targeted determine the severity of exocytic disturbance. Together, this work informs understanding of SYT1 function and further clarifies potential mechanistic targets for treating SYT1-associated NDD.

neuroscience↗