Objective Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease with limited reliable diagnostic biomarkers. We investigated whether gene methylation could meet sensitivity and specificity criteria for a robust biomarker. Methods IFI44L promoter methylation was examined using DNA samples from a discovery set including 377 patients with SLE, 358 healthy controls (HCs) and 353 patients with rheumatoid arthritis (RA). Two independent sets including 1144 patients with SLE, 1350 HCs, 429 patients with RA and 199 patients with primary Sjögren’s syndrome (pSS) were used for validation. Results Significant hypomethylation of two CpG sites within IFI44L promoter, Site1 (Chr1: 79 085 222) and Site2 (Chr1: 79 085 250; cg06872964), was identified in patients with SLE compared with HCs, patients with RA and patients with pSS. In a comparison between patients with SLE and HCs included in the first validation cohort, Site1 methylation had a sensitivity of 93.6% and a specificity of 96.8% at a cut-off methylation level of 75.5% and Site2 methylation had a sensitivity of 94.1% and a specificity of 98.2% at a cut-off methylation level of 25.5%. The IFI44L promoter methylation marker was also validated in an European-derived cohort. In addition, the methylation levels of Site1 and Site2 within IFI44L promoter were significantly lower in patients with SLE with renal damage than those without renal damage. Patients with SLE showed significantly increased methylation levels of Site1 and Site2 during remission compared with active stage. Conclusions The methylation level of IFI44L promoter can distinguish patients with SLE from healthy persons and other autoimmune diseases, and is a highly sensitive and specific diagnostic marker for SLE.

It has long been known that mammalian enterocytes coexpress two members of the fatty acid-binding protein (FABP) family, the intestinal FABP (IFABP) and the liver FABP (LFABP). Both bind long-chain fatty acids and have similar though not identical distributions in the intestinal tract. While a number of in vitro properties suggest the potential for different functions, the underlying reasons for expression of both proteins in the same cells are not known. Utilizing mice genetically lacking either IFABP or LFABP, we directly demonstrate that each of the enterocyte FABPs participates in specific pathways of intestinal lipid metabolism. In particular, LFABP appears to target fatty acids toward oxidative pathways and dietary monoacylglycerols toward anabolic pathways, while IFABP targets dietary fatty acids toward triacylglycerol synthesis. The two FABP-null models also displayed differences in whole body response to fasting, with LFABP-null animals losing less fat-free mass and IFABP-null animals losing more fat mass relative to wild-type mice. The metabolic changes observed in both null models appear to occur by nontranscriptional mechanisms, supporting the hypothesis that the enterocyte FABPs are specifically trafficking their ligands to their respective metabolic fates.

The metabolic fates of radiolabeled sn-2-monoacylglycerol (MG) and oleate (FA) in rat and mouse intestine, added in vivo to the apical (AP) surface in bile salt micelles, or to the basolateral (BL) surface via albuminbound solution, were examined. Mucosal lipid products were quantified, and the results demonstrate a dramatic difference in the esterification patterns for both MG and FA, depending upon their site of entry into the enterocyte. For both lipids, the ratio of triacylglycerol to phospholipid (TG: PL) formed was approximately 10-fold higher for delivery at the AP relative to the BL surface. Further, a 3-fold higher level of FA oxidation was found for BL compared with AP substrate delivery. Incorporation of FA into individual PL species was also significantly different, with .2-fold greater incorporation into phosphatidylethanolamine (PE) and a 3-fold decrease in the phosphatidylcholine:PE ratio for AP-compared with BL-added lipid. Overnight fasting increased the TG:PL incorporation ratio for both AP and BL lipid addition, suggesting that metabolic compartmentation is a physiologically regulated phenomenon. These results support the existence of separate pools of TG and glycerolipid intermediates in the intestinal epithelial cell, and underscore the importance of substrate trafficking in the regulation of enterocyte lipid metabolism.-Storch, J., Y. X. Zhou, and W. S. Lagakos. Metabolism of apical versus basolateral sn-2-monoacylglycerol and fatty acids in rodent small intestine. J. Lipid Res. 2008Res. . 49: 1762Res. -1769 Supplementary key words fatty acidsn-2-Monoacylglycerol (MG) and FAs are the hydrolytic products of ingested triacylglycerol (TG), and provide a major source of calories in Western diets. FAs, in addition, provide critical building blocks for membrane biogenesis, are precursors for regulatory second messengers, and are now considered to directly modulate the expression of specific genes (1). Certain MGs may also function outside of the traditionally appreciated lipid metabolic pathways. For example, sn-2-monoarachidonoyl is thought to act as an endogenous ligand for the cannabinoid receptors (2). Thus, the products of dietary fat digestion, once taken up by the intestinal enterocyte, may have diverse metabolic and cellular fates.It is known that FAs are taken up into the enterocyte across both the apical (AP) plasma membrane as well as across their basolateral (BL) plasma membranes. Further, the intracellular metabolism of FAs is highly dependent upon their site of entry into the cell. In 1975, Gangl and Ockner (3) presented the intriguing finding that luminally derived and plasma-derived palmitic acid had different metabolic fates in the rat enterocyte. Plasma palmitate was primarily oxidized or incorporated into phospholipids (PLs), with relatively low incorporation into TG, whereas palmitate absorbed from the intestinal tract was mainly incorporated into TG. Similar results were shown in humans (4). Studies by Mansbach and Parthasarathy (5) and Mansbach and Dowell (6) fur...

The transcription factors Bach1 and Bach2, which belong to a basic region-leucine zipper (bZip) family, repress target gene expression by forming heterodimers with small Maf proteins. With the ability to bind to heme, Bach1 and Bach2 are important in maintaining heme homeostasis in response to oxidative stress, which is characterized by high levels of reactive oxygen species (ROS) in cells and thereby induces cellular damage and senescence. The inactivation of Bach1 exerts an antioxidant effect. Thus, Bach1 may be a potential therapeutic target of oxidative stress-related diseases. Bach2 participates in oxidative stress-mediated apoptosis and is involved in macrophage-mediated innate immunity as well as the adaptive immune response. Bach1 and Bach2 promote the differentiation of common lymphoid progenitors to B cells by repressing myeloid-related genes. Bach2 is able to regulate class-switch recombination and plasma cell differentiation by altering the concentration of mitochondrial ROS during B cell differentiation. Furthermore, Bach2 maintains T cell homeostasis, influences the function of macrophages, and plays a role in autoimmunity. Bach2-controlling genes with super enhancers in T cells play a key role in immune regulation. However, in spite of new research, the role of Bach1 and Bach2 in immune cells and immune response is not completely clear, nor are their respective roles of in oxidative stress and the immune response, in particular with regard to the clinical phenotypes of autoimmune diseases. The anti-immunosenescence action of Bach and the role of epigenetic modifications of these transcription factors may be important in the mechanism of Bach transcription factors in mediating oxidative stress and cellular immunity.

Background:Intestinal and liver fatty acid-binding proteins (IFABP and LFABP) are coexpressed in the enterocyte, but their individual functions are not known. Results: High fat feeding promotes different phenotypes in IFABP-and LFABP-null mice. Conclusion: IFABP and LFABP have unique intracellular functions, which in turn produce divergent whole body effects. Significance: Enterocyte FABP ablation modulates intestinal lipid metabolism, which contributes to altered systemic energy homeostasis.

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A SAGE analysis of ejaculate from fertile men has revealed a large number of transcripts, which occur in steady frequencies and probably have important roles in spermatogenesis and fertilization.

energy storage, membrane components, and signaling. Extracellular hydrolysis of dietary TG in circulating lipoproteins yields FFAs and sn -2 MG, which are then taken up by cells ( 1,2 ). MGs are also produced intracellularly from membrane phospholipids and the consecutive action of phospholipase C and diacylglycerol lipase, or from the hydrolysis of stored TG by adipose TG lipase (ATGL) and hormone sensitive lipase (HSL) ( 2-5 ). The ultimate fate of intracellular MGs is hydrolysis to FFAs and glycerol or reesterifi cation by acyltransferases into diacylglycerol and TG ( 6, 7 ).MG lipase (MGL) is considered the rate-determining enzyme in MG catabolism. MGL accounts for roughly 85% of MG hydrolysis in the brain, with the remainder being catalyzed by the enzymes ABHD6 and ABHD12 ( 8,9 ). MGL is expressed in many other tissues as well, including brain, liver, skeletal muscle, adipose, and intestine ( 10-13 ). Within cells, MGL localizes to both the cytosolic and membrane fractions and hydrolyzes sn -1 and sn -2 MGs of varying acyl chain lengths and degrees of unsaturation, with almost no activity toward other lipids, such as TG and lyso-phospholipids ( 10,(14)(15)(16)(17)(18).MGL is involved in energy balance through two important functions. Abbreviations: AA, arachidonic acid; AEA, arachidonoyl ethanolamide; 2-AG, 2-arachidonoyl glycerol; AUC, area under the curve; CB, cannabinoid; EC, endocannabinoid; HFD, high-fat diet; HOMA-IR, homeostatic model assessment of insulin resistance; iMGL, mice that overexpress monoacylglycerol lipase specifi cally in the intestinal mucosa; LFD, low-fat diet; MG, monoacylglycerol; MGL, monoacylglycerol lipase; OFTT, oral fat tolerance test; OGTT, oral glucose tolerance test; RER, respiratory exchange ratio .