Biology subjects

Shoucri, B. M.

Publications and source records attributed to Shoucri, B. M..

3 recordsLinked to original sources

bioRxiv2025

A cold-inducible phospholipid--protein interaction in brown fat mitochondria optimizes thermogenic capacity

Cold stress elicits dynamic remodeling of the mitochondrial lipidome in brown adipose tissue (BAT), marked by an increase in arachidonoyl-phosphatidylethanolamine (AA-PE). However, the function of membrane lipid rewiring in thermoregulatory physiology has been a longstanding mystery. Here, we identify LPCAT3 as a cold-regulated O-acyltransferase driving the highly selective accrual of AA-PE in BAT mitochondria. Lipid-based proteomics, molecular dynamics simulations, and bioenergetic analyses reveal that AA-PE partitions at the COX4I1 interface of the Cytochrome c oxidase complex, enhancing electron transport chain (ETC) efficiency. Accordingly, fat-specific Lpcat3-knockout mice have defects in respiratory-dependent BAT thermogenesis and cold tolerance, despite intact {beta}-adrenergic signaling and UCP1 function. Under cold acclimation, Lpcat3-/-BAT exhibits ETC dysfunction and activation of the integrated stress-response. Thus, our study illuminates a cold-regulated lipid-protein interaction as a gating factor in UCP1-dependent thermogenesis.

physiology↗

bioRxiv2022

miR-223 Plays A Critical Role in Obesogen-Enhanced Adipogenesis in Mesenchymal Stem Cells and in Transgenerational Obesity

Exposure of pregnant F0 mouse dams to the obesogen tributyltin (TBT) predisposes unexposed male descendants to obesity and diverts mesenchymal stem cells (MSCs) toward the adipocytic lineage. TBT also promotes adipogenic commitment and differentiation of MSCs, in vitro. We sought to identify TBT-induced factors predisposing MSCs toward the adipocytic fate. We exposed mouse MSCs to TBT, the PPAR{gamma}-selective agonist rosiglitazone or the RXR-selective agonist LG-100268 and determined their transcriptomal profiles to determine candidate microRNAs (miR) regulating adipogenic commitment and differentiation. Of the top 10 candidate microRNAs predicted by Ingenuity Pathway Analysis, miR-21, miR-33 and miR-223 were expressed in a manner consistent with an ability to differentially regulate target genes during adipogenesis. After 24 hours exposure to 50 nM TBT, miR-223 levels in MSCs were increased and expression of its target genes ZEB1, NFIB, and FOXP1 was decreased. Both ROSI and TBT increased miR-223 levels, and this induction was inhibited by the PPAR{gamma} antagonist T0070907 but not by the RXR antagonists HX531 or UVI3003, placing miR-223 downstream of PPAR{gamma}. Chromatin immunoprecipitation confirmed TBT-induced binding of PPAR{gamma} to regulatory elements in the miR-223 promoter. miR-223 levels were elevated in white adipose tissue of F2 and F3 male descendants of pregnant F0 mouse dams exposed to 50 nM TBT throughout gestation. miR-223 levels were further induced in males fed with an increased fat diet. We infer that TBT induced miR-223 expression and increased adipogenesis in MSCs through the PPAR{gamma} pathway and that transgenerationally increased expression of miR-223 plays an important role in the development of obesity caused by TBT exposure.

developmental biology↗

bioRxiv2017

Ancestral perinatal obesogen exposure results in a transgenerational thrifty phenotype in mice

Ancestral environmental exposures to non-mutagenic agents can exert effects in unexposed descendants. This transgenerational inheritance has significant implications for understanding disease etiology. The obesogen hypothesis proposes that exposure to obesogenic chemicals can lead to increased adiposity, in vivo. Here we show that exposure of F0 mice to the obesogen tributyltin (TBT) throughout pregnancy and lactation predisposes unexposed F4 male descendants to obesity when dietary fat is increased. Analyses of body fat, plasma hormone levels, and visceral white adipose tissue DNA methylome and transcriptome collectively indicate that the F4 obesity is consistent with a leptin resistant, \"thrifty phenotype\". Ancestral TBT exposure induces global changes in DNA methylation together with altered expression of metabolism-relevant genes when the F4 animals were exposed to dietary challenges. Analysis of chromatin accessibility in F3 and F4 sperm reveal significant differences between control and TBT groups and significant similarities between F3 and F4 TBT groups that overlap with areas of differential methylation in F4 adipose tissue. Taken together, our data suggest that ancestral TBT exposure induces changes in higher order chromatin organization transmissible through meiosis and mitosis.\n\nNon-technical summaryAncestral obesogen exposure in mice causes obesity in untreated F4 male descendants by inducing heritable changes in genome architecture that predispose these animals to become obese when dietary fat is increased modestly. This result is consistent with these animals having a leptin-resistant, \"thrifty\" phenotype

developmental biology↗