Project description:Brown and beige fat share a remarkably similar transcriptional program that supports fuel oxidation and thermogenesis. The chromatin-remodeling machinery that governs genome accessibility and renders adipocytes poised for thermogenic activation remains elusive. BAF60a serves an indispensable role in cold-induced thermogenesis in brown fat. Surprisingly, fat-specific BAF60a inactivation triggers more pronounced browning of inguinal white adipose tissue. These results suggest a dichotomous role of BAF60a-mediated chromatin remodeling in transcriptional control of brown and beige gene programs. To elucidate the mechanism, we performed microarray annalysis in inguinal white adipose tissues from mice after chronic cold exposure.
Project description:We used microarrays to detail the gene expression profile during WAT -beige transition by treatment of beta adrenergic receptor agonist .
Project description:We used microarrays to detail the gene expression profile during WAT -beige transition by treatment of beta adrenergic receptor agonist . Stromal vascular fractions (SVF) from mice (n = 3/group) that received vehicle or beta3 adrenergic receptor agonist, CL, treatment were served for RNA extraction and hybridization on Affymetrix microarrays. We are trying to find out angiogenic factors genes dynamics during white adipose tissues (WAT) - beige transition.
Project description:Two types of UCP1 positive cells-brown and beige adipocytes exist in mammals. Beige adipocytes are very plastic, and can be dynamically regulated by environment.Beige adipocytes formed postnatally in subcutaneous inguinal white adipose tissue (iWAT) lost thermogenic gene expression and multilocular morphology at adult stage, but cold could restore their “beigeing” characteristics, a phenomenon termed as beige adipocyte renaissance. Our results showed that beige cell maintenance and renaissance in adult mice were regulated by cAMP and HDAC4 signaling in white adipocytes non-cell autonomously. Genetic modulations of various components of this cAMP-HDAC4 cascade (e.g. LKB1) led to persistent browning and reduced adiposity independent of thermogenesis. To further study the mechanisms of beige adipocytes maintenance, we performed RNA-seq with samples from inguinal white adipose tissues of WT, AdipoqCre LKB1 F/F, and AdipoqCre LKB1 F/F; HDAC4 F/F mice.Our studies will move the beige adipocyte field forward and attract clinical applications to target beige adipocyte renaissance.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Interorgan crosstalk via secreted hormones and metabolites is a fundamental aspect of mammalian metabolic physiology. Beyond the highly specialized endocrine cells, peripheral tissues are emerging as an important source of metabolic hormones that influence energy and nutrient metabolism and contribute to disease pathogenesis. Neuregulin 4 (Nrg4) is a fat-derived hormone that protects mice from nonalcoholic steatohepatitis (NASH) and NASH-associated liver cancer by shaping hepatic lipid metabolism and the liver immune microenvironment. Despite its enriched expression in brown fat, whether NRG4 plays a role in thermogenic response and mediates the metabolic benefits of cold exposure remain unexplored. Here we show that Nrg4 expression in inguinal white adipose tissue (iWAT) is highly responsive to chronic cold exposure. Nrg4 deficiency impairs beige fat induction and renders mice more susceptible to diet-induced metabolic disorders under mild cold conditions. Using mice with adipocyte and hepatocyte-specific Nrg4 deletion, we reveal that adipose tissue-derived NRG4, but not hepatic NRG4, is essential for beige fat induction following cold acclimation. Furthermore, treatment with recombinant NRG4-Fc fusion protein promotes beige fat induction in iWAT and improves metabolic health in diet-induced obese mice. These findings highlight a critical role of NRG4 in mediating beige fat induction and preserving metabolic health under mild cold conditions.
Project description:Mice with beige fat-selective ablation of Bmal1 were generated by crossing Bmal1fl/fl with Prrx1-Cre transgenics. Inguinal subcutaneous adipsoe tissues were collected under ambient temperature at 220C or cold acclimations at 10oC for two weeks.
Project description:Brown fat generates heat via the mitochondrial uncoupling protein UCP1, defending against hypothermia and obesity. Recent data suggest that there are two distinct types of brown fat: classical brown fat derived from a myf-5 cellular lineage and UCP1-positive cells that emerge in white fat from a non-myf-5 lineage. Here, we report the isolation of “beige” cells from murine white fat depots. Microarray analysis of the differentiated clonal inguinal and interscapular adipocytes in the presence of forskolin (10mM). These samples were profiled using Affymetrix mouse 430 2.0 arrays, 26 samples in total.