Mobilization of fatty acids from triglyceride stores in adipose tissue requires lipolytic enzymes. Dysfunctional lipolysis affects energy homeostasis and may contribute to the pathogenesis of obesity and insulin resistance. Until now, hormone-sensitive lipase (HSL) was the only enzyme known to hydrolyze triglycerides in mammalian adipose tissue. Here, we report that a second enzyme, adipose triglyceride lipase (ATGL), catalyzes the initial step in triglyceride hydrolysis. It is interesting that ATGL contains a "patatin domain" common to plant acyl-hydrolases. ATGL is highly expressed in adipose tissue of mice and humans. It exhibits high substrate specificity for triacylglycerol and is associated with lipid droplets. Inhibition of ATGL markedly decreases total adipose acyl-hydrolase activity. Thus, ATGL and HSL coordinately catabolize stored triglycerides in adipose tissue of mammals.

Functional impairment of HDL may contribute to the excess cardiovascular mortality experienced by patients with renal disease, but the effect of advanced renal disease on the composition and function of HDL is not well understood. Here, we used mass spectrometry and biochemical analyses to study alterations in the proteome and lipid composition of HDL isolated from patients on maintenance hemodialysis. We identified a significant increase in the amount of acute phase protein serum amyloid A1, albumin, lipoprotein-associated phospholipase A2, and apoC-III composing uremic HDL. Furthermore, uremic HDL contained reduced phospholipid and increased triglyceride and lysophospholipid. With regard to function, these changes impaired the ability of uremic HDL to promote cholesterol efflux from macrophages. In summary, the altered composition of HDL in renal disease seems to inhibit its cardioprotective properties. Assessing HDL composition and function in renal disease may help identify patients at increased risk for cardiovascular disease.

SUMMARY Numerous studies in humans link a nonsynonymous genetic polymorphism (I148M) in adiponutrin (ADPN) to various forms of fatty liver disease and liver cirrhosis. Despite its high clinical relevance, the molecular function of ADPN and the mechanism by which I148M variant affects hepatic metabolism are unclear. Here we show that ADPN promotes cellular lipid synthesis by converting lysophosphatidic acid (LPA) into phosphatidic acid. The ADPN-catalyzed LPA acyltransferase (LPAAT) reaction is specific for LPA and long-chain acyl-CoAs. Wild-type mice receiving a high-sucrose diet exhibit substantial upregulation of Adpn in the liver and a concomitant increase in LPAAT activity. In Adpn-deficient mice, this diet-induced increase in hepatic LPAAT activity is reduced. Notably, the I148M variant of human ADPN exhibits increased LPAAT activity leading to increased cellular lipid accumulation. This gain of function provides a plausible biochemical mechanism for the development of liver steatosis in subjects carrying the I148M variant.

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This article is available online at http://www.jlr.org more than the skin ( 1 ). Traditional cardiovascular risk factors, such as hypertension, dyslipidemia, and obesity, are more frequent in psoriatic patients ( 2-4 ). However, even after adjusting for these risk factors, psoriasis has been shown to be associated with a higher incidence of myocardial infarction, stroke, and cardiovascular mortality ( 3,5,6 ). In moderate to severe psoriasis, a signifi cantly deteriorated lipid profi le was observed compared with healthy controls, with higher values of low-density lipoprotein, triglycerides, and signifi cantly decreased HDL levels ( 7 ).Recent studies clearly demonstrated that infl ammation impairs reverse cholesterol transfer in vivo ( 8, 9 ), providing evidence that infl ammation impairs HDL function. Emerging evidence suggests that assessment of HDL plasma concentrations alone is insuffi cient and indicate that the quality, rather than the mere quantity, of HDL determines its potential benefi cial effects against atherosclerosis ( 10 ). HDL is a complex lipoprotein particle with a broad variety of functions, also exerting atheroprotective activity via effects on the endothelium and by potent antiinfl ammatory capabilities ( 11-13 ). Recent studies have identifi ed HDL-associated proteins to be involved in the regulation of lipid metabolism, complement activation, growth-factor secretion, and proteolysis (14)(15)(16)(17)(18)(19).Functional impairment of HDL may contribute to the increased cardiovascular mortality experienced by psoriatic patients, but the impact of psoriasis on the composition and function of HDL has not been assessed. As qualitative alterations of HDL seem to be linked with increased cardiovascular complications, we hypothesized that HDL from psoriatic patients displays altered protein cargo and lipid composition, thereby rendering HDL dysfunctional.Abstract Psoriasis, a chronic infl ammatory skin disease, has been linked to increased myocardial infarction and stroke. Functional impairment of HDL may contribute to the excess cardiovascular mortality of psoriatic patients. However, data available regarding the impact of psoriasis on HDL composition and function are limited. HDL from psoriasis patients and healthy controls was isolated by ultracentrifugation and shotgun proteomics, and biochemical methods were used to monitor changed HDL composition. We observed a signifi cant reduction in apoA-I levels of HDL from psoriatic patients, whereas levels of apoA-II and proteins involved in acute-phase response, immune response, and endopeptidase/protease inhibition were increased. Psoriatic HDL contained reduced phospholipid and cholesterol. With regard to function, these compositional alterations impaired the ability of psoriatic HDL to promote cholesterol effl ux from macrophages. Importantly, HDLcholesterol effl ux capability negatively correlated with psoriasis area and severity index. We observed that control HDL, as well as psoriatic HDL, inhibited dihydrorhodamine (DHR) oxidation to a similar...

Measured cTnT concentrations were chronically elevated in the majority of patients with skeletal myopathies, whereas cTnI elevation was rare. Our data indicate that cross-reaction of the cTnT immunoassay with skeletal muscle troponin isoforms was the likely cause.

From a screening on agar plates with bis(benzoyloxyethyl) terephthalate (3PET), a Bacillus subtilis p-nitrobenzylesterase (BsEstB) was isolated and demonstrated to hydrolyze polyethyleneterephthalate (PET). PET-hydrolase active strains produced clearing zones and led to the release of the 3PET hydrolysis products terephthalic acid (TA), benzoic acid (BA), 2-hydroxyethyl benzoate (HEB), and mono-(2-hydroxyethyl) terephthalate (MHET) in 3PET supplemented liquid cultures. The 3PET-hydrolase was isolated from non-denaturating polyacrylamide gels using fluorescein diacetate (FDA) and identified as BsEstB by LC-MS/MS analysis. BsEstB was expressed in Escherichia coli with C-terminally fused StrepTag II for purification. The tagged enzyme had a molecular mass of 55.2 kDa and a specific activity of 77 U/mg on p-nitrophenyl acetate and 108 U/mg on p-nitrophenyl butyrate. BsEstB was most active at 40°C and pH 7.0 and stable for several days at pH 7.0 and 37°C while the half-life times decreased to 3 days at 40°C and only 6 h at 45°C. From 3PET, BsEstB released TA, MHET, and BA, but neither bis(2-hydroxyethyl) terephthalate (BHET) nor hydroxyethylbenzoate (HEB). The kcat values decreased with increasing complexity of the substrate from 6 and 8 (s-1) for p-nitrophenyl-acetate (4NPA) and p-nitrophenyl-butyrate (4NPB), respectively, to 0.14 (s-1) for bis(2-hydroxyethyl) terephthalate (BHET). The enzyme hydrolyzed PET films releasing TA and MHET with a concomitant decrease of the water-contact angle (WCA) from 68.2°±1.7° to 62.6°±1.1° due to formation of novel hydroxyl and carboxyl groups. These data correlated with a fluorescence emission intensity increase seen for the enzyme treated sample after derivatization with 2-(bromomethyl)naphthalene.

Background: Conjugative plasmid transfer is the prevalent means for spreading antibiotic resistance genes among bacteria.Results: Surface exposure of transfer protein TraM from the Gram-positive (G+) plasmid pIP501 was confirmed, and its crystal structure was solved.Conclusion: Structural relations to type IV secretion (T4S) proteins provide a novel classification scheme.Significance: The novel classification will help elucidate structure-function relationships in G+ T4S systems.