Project description:The high prevalence of obesity has focused attention on defining the pathophysiological processes that underlie susceptibility or resistance to its deleterious metabolic consequences. Mice lacking translin (Tsn), a gene implicated in a variety of biological functions from transcription to microRNA degradation, display extremely high levels of adiposity, comparable to those found in well-known genetic models of obesity, such as melanocortin 4 receptor or leptin knockout (KO) mice. Although translin KO mice display increased adiposity they retain normal glucose tolerance. In contrast, wild-type (WT) mice placed on a high-fat diet until they match translin KO adiposity levels are glucose intolerant, as expected. Conversely, translin KO mice display prominent hepatic steatosis that is more severe than that of adiposity-matched WT mice. The ability of translin KO mice to retain normal glucose tolerance in the face of massive tissue expansion may be due to three factors: preferential accumulation of subcutaneous fat, reduced levels of TNF mRNA in both adipose and hepatic tissue, and elevated levels of plasma adiponectin. Further studies aimed at defining the molecular bases for these phenotypes may yield new approaches to limit the adverse metabolic consequences of obesity.
Project description:Obesity is linked to the development of metabolic disorders. Expansion of white adipose tissue (WAT) from hypertrophy of pre-existing adipocytes and/or differentiation of precursors into new mature adipocytes contributes to obesity. We found that Nck2 expression is largely restricted to WAT, raising the hypothesis that it may play a unique function in that tissue. Using mice lacking Nck2, we found that Nck2 regulates adipocyte hypertrophy thus contributing to increased adiposity and progressive glucose intolerance, insulin resistance and hepatic steatosis. These findings were recapitulated in humans such that Nck2 expression in omental WAT was inversely correlated with the degree of obesity. Mechanistically, Nck2 deficiency promoted the induction of an adipocyte differentiation program and signaling by the PERK-eIF2α-ATF4 pathway in agreement with a role for the unfolded protein response in adipogenesis. These findings uncover Nck2 as a novel regulator of adipogenesis and that perturbation in its functionality contributes to adiposity-related metabolic disorders. Differential gene expression profile between epididymal white adipose tissue of Nck2-/- and Nck2+/+ mice by RNA sequencing (Illumina HiSEq 2000)
Project description:Homozygous K107R mutation of PPARg in mice alters the expression of its downstream target genes and increases insulin sensitivity but not adiposity.
Project description:Obesity is linked to the development of metabolic disorders. Expansion of white adipose tissue (WAT) from hypertrophy of pre-existing adipocytes and/or differentiation of precursors into new mature adipocytes contributes to obesity. We found that Nck2 expression is largely restricted to WAT, raising the hypothesis that it may play a unique function in that tissue. Using mice lacking Nck2, we found that Nck2 regulates adipocyte hypertrophy thus contributing to increased adiposity and progressive glucose intolerance, insulin resistance and hepatic steatosis. These findings were recapitulated in humans such that Nck2 expression in omental WAT was inversely correlated with the degree of obesity. Mechanistically, Nck2 deficiency promoted the induction of an adipocyte differentiation program and signaling by the PERK-eIF2α-ATF4 pathway in agreement with a role for the unfolded protein response in adipogenesis. These findings uncover Nck2 as a novel regulator of adipogenesis and that perturbation in its functionality contributes to adiposity-related metabolic disorders.
Project description:C18ORF25 is a homolog of Arkadia (RNF111), an E3 ubiquitin ligase with SUMO-interaction motifs (SIMs) (PMID: 31417085). However, C18ORF25 lacks the entire C-terminal RING domain of RNF111 which is required for ubiquitin binding suggesting it lacks ubiquitination activity and may therefore act as an adaptor or signalling scaffold (PMID: 26283374). We have previously shown that mice lacking C18Orf25 throughout the entire body have increased adiposity, decreased lean mass, lower exercise capacity and significantly reduced ex vivo skeletal muscle force production (PMID: 35882232). Skeletal muscle isolated from C18Orf25 knockout (KO) mice have reduced cAMP-dependent protein kinase A (PKA) levels, and reduced phosphorylation of several contractile proteins and proteins involved in calcium handling. Furthermore, analysis of single muscle fibres from C18Orf25 KO mice revealed impaired SR calcium cycling in fast-twitch fibres only (PMID: 35882232). Hence, we investigated these mechanisms by developing an integrated single-fibre physiology and single-fibre proteomic platform. The platform enabled us to identify hundreds of novel phenotype:protein correlations. The analysis also enabled us to identify proteome differences specifically in FT fibres following loss of C18ORF25. Taken together, our data suggest C18ORF25 is likely a multi-functional protein with several underlying mechanisms contributing to skeletal muscle physiology.
Project description:Many genes have been implicated in WAT lipid metabolism, including tripartite motif containing 28 (Trim28), a gene proposed to primarily influence adiposity via epigenetic mechanisms in embryonic development. We set out to determine if adipose specific deletion of Trim28 led to changes in adipose tissue function and molecular phenotype. We performed transcriptomics analysis on adipose tissue taken from WT and adipose specific Trim28 KO mice to investigate their molecular phenotype, and to identify pathways altered in KO animals.
Project description:Lysosome-enriched fractions from the liver of Cln8 KO mice and WT mice. Included are four datasets: 1. Lysosome-enriched fraction from the liver of Cln8 KO mice, replicate 1 (CLN8_KO_1). 2. Lysosome-enriched fraction from the liver of Cln8 KO mice, replicate 2 (CLN8_KO_2). 3. Lysosome-enriched fraction from the liver of WT mice, replicate 1 (WT_1). 4. Lysosome-enriched fraction from the liver of WT mice, replicate 2 (WT_2).
Project description:Adipose tissue gene expression was profiled from perigonadal adipose tissue of mice whose body mass and insulin sensitivity varied as a function of diet, gender, monogenic mutations and insulin sensitizing therapies. Mice were 22-24 weeks of age and sacrificed between 2-3 hours into the light portion of a 12/12 dark-light cycle. The goal was to identify transcripts whose adipose tissue expression is correlated with adiposity, insulin sensitivity and other measures of metabolic function. Keywords: population