ABHD6 knockdown significantly increased total hepatic levels of phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE), lysophosphatidylethanolamine (LPE), phosphatidylglycerol (PG), lysophosphatidylglycerol (LPG), phosphatidylinositol (PI), lysophosphatidylinositol (LPI), and phosphatidylserine (PS) (Figure 6B, 6C, 6D, 6E, 6F, 6H, 6I, 6J, 6K, and 6L), without altering hepatic levels of phosphatidic acid or lysophosphatidic acid species (Figure 6A, 6G, and Figure S4C)

ABHD6 knockdown significantly increased total hepatic levels of phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE), lysophosphatidylethanolamine (LPE), phosphatidylglycerol (PG), lysophosphatidylglycerol (LPG), phosphatidylinositol (PI), lysophosphatidylinositol (LPI), and phosphatidylserine (PS) (Figure 6B, 6C, 6D, 6E, 6F, 6H, 6I, 6J, 6K, and 6L), without altering hepatic levels of phosphatidic acid or lysophosphatidic acid species (Figure 6A, 6G, and Figure S4C). unannotated genes YM-90709 recognized by sequencing efforts. Although many unannotated gene products belong to structurally related gene or protein families, which may provide important functional clues, membership to such families does not usually accurately predict the true biochemical and physiological role of proteins. Genes encoding the / hydrolase fold domain name (ABHD) protein family are present in all reported genomes (Nardini and Dijkstra, 1999; Hotelier et al., 2004), and conserved structural motifs shared by these proteins predict common functions in lipid metabolism and transmission transduction (Lefevre et al., 2001; Fiskerstrand et al., 2010; Long et al., 2011; Simon and Cravatt, 2006; Montero-Moran et al., 2009; Blankman et al., 2007; Lord et al., 2011; Brown et al., 2010). Furthermore, mutations in several members of the ABHD protein family have been implicated in inherited inborn errors of lipid metabolism (Lefevre et al., 2001; Fiskerstrand et al., 2010). Most recently, studies in cell and animal models have revealed important functions for ABHD proteins in glycerophospholipid metabolism, lipid transmission transduction, and metabolic disease (Long et al., 2011; Simon and Cravatt 2006; Montero-Moran et al., 2009; Blankman et al., 2007; Lord et al., 2011; Brown et al., 2010). However, the physiological substrates and products for these lipid metabolizing enzymes and their broader role in metabolic pathways remain largely uncharacterized. Given this, functional annotation of ABHD enzymes holds clear promise for drug discovery targeting diseases of altered lipid metabolism and lipid signaling. ABHD5, also known as CGI-58, has been analyzed quite extensively due to its important role in triacylglycerol (TAG) metabolism, lipid signaling, and genetic association with the human disease YM-90709 Chanarin-Dorfman Syndrome (CDS) (Lefevre et al., 2001; Montero-Moran et al., 2009; Lord et al., 2011; Brown et al., 2010; Lass et al., 2006; Schweiger et al., 2009). Given ABHD5’s clear role in nutrient metabolism and lipid transmission transduction, we aimed to test whether the closely related enzyme ABHD6 might play a similar role in lipid signaling and metabolic disease. ABHD6 has recently been described as an enzymatic regulator of endocannabinoid (ECB) signaling in the brain (Blankman et al., 2007; Marrs et al., 2010; Marrs et al., 2011). However, ABHD6 is ubiquitously expressed, and the biochemical and physiological functions of ABHD6 outside of the central nervous system have not been analyzed. Furthermore, unbiased identification of ABHD6 substrates has not been reported. To address this we selectively knocked down ABHD6 in peripheral tissues, allowing us to identify novel substrates and to uncover YM-90709 a previously underappreciated role for ABHD6 in promoting the metabolic syndrome. These studies demonstrate that ABHD6 plays a non-redundant enzymatic role in promoting the metabolic disorders induced by high-fat feeding, and suggest that ABHD6 inhibition may be effective in preventing obesity, nonalcoholic fatty liver disease, and type II diabetes. RESULTS ABHD6 is usually Ubiquitously Expressed and Upregulated by High Fat Diet Feeding Mouse ABHD6 is usually a 336 amino acid protein that shares high sequence identity with its human (94%), macaque (94%), and rat (97%) orthologues (Physique 1A). A highly conserved active site serine nucleophile is found at residue 148 (Physique 1A), which is usually predicted to be necessary for enzyme catalysis. ABHD6 mRNA is usually ubiquitously expressed (Physique 1B), with highest expression in small intestine, liver, and brown adipose tissue in mice fed standard rodent chow. Additionally, high fat diet feeding increases ABHD6 mRNA expression in Mouse monoclonal to KLHL11 the small intestine and the liver (Physique 1B). This transcriptional regulation of ABHD6 in metabolic tissue prompted us to examine whether ABHD6 may be an important mediator of high excess fat diet-induced metabolic disease. Open in a separate window Physique 1 ABHD6 is usually Ubiquitously Expressed and is Regulated by High Fat Diet(A) Alignment of human (Hu), macaque (Ma), rat (Ra), and mouse (Mu) ABHD6 orthologues showing conserved (gray) and divergent residues (white); C = consensus sequence. The underlined letters represent the consensus GXSXG nucleophile elbow made up of the predicted serine nucleophile S148 (black box). (B) mRNA expression analysis of ABHD6 in C57BL/6 mouse tissues following 10 weeks of chow or high fat diet (HF) feeding. Data symbolize the imply SEM (n = 4); * = YM-90709 P 0.05 (vs. chow-fed group within each tissue). AU = arbitrary models; Liv = liver; He = heart; Lu = lung; BAT = brown adipose tissue; Kid = kidney; Spl.