Biology subjects

Darehshouri, A.

Publications and source records attributed to Darehshouri, A..

3 recordsLinked to original sources

bioRxiv2026

The functional neuronal lipotype is specified by activity and PS synthesis using dietary and lysosomal inputs

Neurons maintain specialized membranes necessary for lifelong circuit function. While neuronal membranes thus contain unique lipidomes, how and why specific lipids become synaptically enriched remains mysterious. Here, we identify a conserved hallmark of mature neurons, phosphatidylserines containing omega-3 fatty acids (n-3 PS), which dynamically accumulate during synaptogenesis from Drosophila to humans. This neuronal lipotype depends on dietary n-3 and lysosomal catabolism mediated by Saposin, the phospholipase PLA2G15, and the lysophospholipid transporter spin/SPNS1. Reducing neuronal PS biosynthesis by targeting the PS synthase (Pss) caused lipidomic, synaptic, and behavioral deficits exacerbated by impaired glycerophospholipid catabolism. While dietary, lysosomal, and lipoprotein manipulations broadly altered n-3 levels, silencing developmental activity-templating neurons selectively reduced n-3 PS. Remarkably, pathogenic Pss variants lacking feedback inhibition similarly reduced n-3 PS and impaired circuit function. As n-3 PS is reduced during neurodegeneration but absent from iPSC-derived neurons, important relationships between lipotype and physiology may not be recapitulated in vitro.

neuroscience↗

bioRxiv2026

Microglia drive demyelination via multiple sclerosis antibodies and BTK signaling

Microglia are the predominant immune cells in multiple sclerosis (MS) demyelinating lesions, where they phagocytose myelin, but whether they destroy myelin or merely scavenge its debris is unknown. Here, we explore whether pathogenic autoantibodies found in MS may induce the phagocytic destruction of myelin by microglia. Applying patient-derived, myelin-targeting antibodies to the mouse cortex, we developed an in vivo model of MS with focal demyelination that depended on epitope specificity and Fc gamma receptor and complement binding. Longitudinal monitoring of microglia-myelin interactions using in vivo two-photon microscopy revealed rapid microglial envelopment of intact myelin driving myelin loss, while single-cell RNA sequencing identified a demyelination-associated microglial signature. Parallel changes were observed in human MS lesions, where microglia enveloped intact myelin and similar genes were upregulated. Inhibition of Brutons tyrosine kinase (BTK) limited microglial transcriptional changes and prevented myelin loss following microglial envelopment. These findings directly implicate microglia in pathological myelin loss and support BTK inhibition as a therapeutic strategy to prevent demyelination by modulating microglia behavior.

neuroscience↗

bioRxiv2025

GPR182 is a lipoprotein receptor for dietary fat absorption

The lymphatic system plays a central role in lipid absorption, which transports chylomicrons from the small intestine to the circulation. However, the molecular mechanism by which chylomicrons get into the intestinal lymphatics is unknown. Here we demonstrated that GPR182, a receptor in lymphatic endothelial cells (LECs), mediates dietary fat absorption. GPR182 knockout mice are resistant to dietary-induced obesity. GPR182 ablation in mice leads to poor lipid absorption and thereby a delay in growth during development. GPR182 binds and endocytoses lipoproteins broadly. Mechanistically, loss of GPR182 prevents chylomicrons from entering the lacteal lumen of the small intestine. GPR182 blockage with a monoclonal antibody (mAb) protects mice from dietary induced obesity. Together, our study identifies GPR182 as a lipoprotein receptor that mediates dietary fat absorption.

physiology↗