Bensalem, J. | bioRxiv Science

bioRxiv2024

Autophagy across tissues of aging mice

Autophagy is a waste-disposal pathway that protects against age-related pathology. It is widely accepted that autophagy declines with age, yet the role that sex and diet-related obesity play during aging remain unknown. Here, we present the most comprehensive in vivo study of autophagic flux to date. We employed transgenic mice overexpressing tandem-florescent LC3B (RFP-GFP-LC3B) to measure autophagic flux in the blood (PBMCs), heart, and motor cortex neurons of aging mice that were fed regular chow or a high-fat diet for 6-, 12- or 18-months. In male mice, aging decreased autophagic flux in the heart, increased it in the blood, and had no effect in motor cortex neurons. Age-dependent changes autophagic flux were less pronounced in female mice. High-fat diet influenced autophagic flux in the blood and heart of male but not female mice. Overall, we uncovered sexual dimorphisms that underpin how autophagy changes with age across different tissues and in response to a high-fat diet.

cell biology↗

bioRxiv2024

Functional analysis of the epilepsy gene Pcdh19 using a novel GFP-reporter mouse model

PCDH19 is a cell adhesion molecule belonging to the delta2-protocadherin subfamily that plays a critical role in brain development, neuronal migration, synaptic organisation, and neural circuit formation. Mutations in PCDH19 cause PCDH19-clustering epilepsy, an infantile-onset disorder characterized by seizures and intellectual disabilities. Despite the increasing development of constitutive cellular and murine models to investigate the effects of Pcdh19 knockout on cell-cell interactions and cellular function, the spatiotemporal consequences of its loss remain poorly understood. To address this gap, we generated and validated a novel conditional Pcdh19 knockout mouse model incorporating a GFP reporter (Pcdh19-cKO-GFP), enabling cell type-specific and temporally controlled gene deletion and direct visualization of recombination events. Using a neuronal Syn1-Cre driver, we demonstrate that targeted deletion of Pcdh19 in neurons results in altered hippocampal neurogenesis and mouse behaviour. We further demonstrate the versatility of this model using a doxycycline-inducible Cre system, enabling temporally controlled deletion of Pcdh19 and the modelling of disease-relevant phenotypes. Finally, we validate adeno-associated viral (AAV) vector-mediated recombination as a strategy for precise postnatal manipulation of Pcdh19 expression. Collectively, this Pcdh19-cKO-GFP model provides a powerful and flexible genetic tool to interrogate the cell type specific and temporary regulated functions of PCDH19 in the developing and postnatal brain under physiological and disease conditions.

neuroscience↗