N 6-methyladenosine (m 6 A) mRNA modifications play critical roles in various biological processes. However, no study addresses the role of m 6 A in macroautophagy/autophagy. Here, we show that m 6 A modifications are increased in H/R-treated cardiomyocytes and ischemia/reperfusion (I/R)-treated mice heart. We found that METTL3 (methyltransferase like 3) is the primary factor involved in aberrant m 6 A modification. Silencing METTL3 enhances autophagic flux and inhibits apoptosis in H/R-treated cardiomyocytes. However, overexpression of METTL3 or inhibition of the RNA demethylase ALKBH5 has an opposite effect, suggesting that METTL3 is a negative regulator of autophagy. Mechanistically, METTL3 methylates TFEB, a master regulator of lysosomal biogenesis and autophagy genes, at two m 6 A residues in the 3ʹ-UTR, which promotes the association of the RNA-binding protein HNRNPD with TFEB pre-mRNA and subsequently decreases the expression levels of TFEB. Further experiments show that autophagic flux enhanced by METTL3 deficiency is TFEB dependent. In turn, TFEB regulates the expression levels of METTL3 and ALKBH5 in opposite directions: it induces ALKBH5 and inhibits METTL3. TFEB binds to the ALKBH5 promoter and activates its transcription. In contrast, inhibition of METTL3 by TFEB does not involve transcriptional repression but rather downregulation of mRNA stability, thereby establishing a negative feedback loop. Together, our work uncovers a critical link between METTL3-ALKBH5 and autophagy, providing insight into the functional importance of the reversible mRNA m 6 A methylation and its modulators in ischemic heart disease.

The PNI is a simple and useful marker not only to identify patients at increased risk for postoperative complications, but also to predict long-term survival after total gastrectomy. The PNI should be included in the routine assessment of advanced gastric cancer patients.

Age ≥ 70 years was an independent prognostic factor for gastric cancer after gastrectomy. D1 resection is appropriate and postoperative chemotherapy is possibly unnecessary for elderly patients with gastric cancer.

. Hydrogen sulfide reduces serum triglyceride by activating liver autophagy via the AMPK-mTOR pathway. Am J Physiol Endocrinol Metab 309: E925-E935, 2015. First published October 6, 2015; doi:10.1152/ajpendo.00294.2015.-Autophagy plays an important role in liver triglyceride (TG) metabolism. Inhibition of autophagy could reduce the clearance of TG in the liver. Hydrogen sulfide (H2S) is a potent stimulator of autophagic flux. Recent studies showed H2S is protective against hypertriglyceridemia (HTG) and noalcoholic fatty liver disease (NAFLD), while the mechanism remains to be explored. Here, we tested the hypothesis that H2S reduces serum TG level and ameliorates NAFLD by stimulating liver autophagic flux by the AMPK-mTOR pathway. The level of serum H2S in patients with HTG was lower than that of control subjects. Sodium hydrosulfide (NaHS, H2S donor) markedly reduced serum TG levels of male C57BL/6 mice fed a high-fat diet (HFD), which was abolished by coadministration of chloroquine (CQ), an inhibitor of autophagic flux. In HFD mice, administration of NaSH increased the LC3BII-to-LC3BI ratio and decreased the p62 protein level. Meanwhile, NaSH increased the phosphorylation of AMPK and thus reduced the phosphorylation of mTOR in a Western blot study. In cultured LO2 cells, high-fat treatment reduced the ratio of LC3BII to LC3BI and the phosphorylation of AMPK, which were reversed by the coadministration of NaSH. Knockdown of AMPK by siRNA in LO2 cells blocked the autophagic enhancing effects of NaSH. The same qualitative effect was observed in AMPK␣2 Ϫ/Ϫ mice. These results for the first time demonstrated that H2S could reduce serum TG level and ameliorate NAFLD by activating liver autophagy via the AMPKmTOR pathway. hydrogen sulfide; triglyceride; NAFLD; autophagy; AMPK HYPERTRIGLYCERIDEMIA (HTG) is the most common lipid metabolism disorder and is an important independent risk factor for cardiovascular and cerebrovascular diseases (2, 10, 29). The liver plays a cardinal role in lipid metabolism. Increased production and/or decreased clearance of triglyceride (TG) in the liver inevitably results in HTG (13, 30), while TG accumulation in the liver can lead to nonalcoholic fatty liver disease (NAFLD) (40). NAFLD is the most prevalent chronic liver disease in the developed world and is an important risk factor for the development of liver fibrosis and cirrhosis and predisposes to the development of hepatocellular carcinoma (1, 26).Recent research suggests that autophagy participates in the regulation of liver lipid metabolism (5, 33, 34). Autophagy modulates hepatocyte lipid metabolism through lipophagy, which involves sequestration of lipid drops in double-membrane autophagosomes, followed by fusion with lysosomes to form autolysosomes, and subsequent degradation of TG by lipases within the autolysosomes. Reduction of liver cell autophagic activity causes decreased lipolysis and provokes free fatty acid (FFA) ␤-oxidation, resulting in hepatic steatosis and often progresses to NAFLD and HTG (34).AMP-activated pro...

Obstructive sleep apnea (OSA) is closely related to atrial fibrillation (AF). However, the roles and mechanisms of chronic OSA in atrial remodeling are still unclear. Canine model of chronic OSA was simulated by stopping the ventilator and closing the airway for 4 h per day and lasting for 12 weeks. AF inducibility and duration was increased while atrial effective refractory period (AERP) was shortened after chronic apnea. Meanwhile, upregulation of proteins encoding inward rectifier K(+) current (IK1), delayed rectifier K(+) current (IKr and IKs), acetylcholine activated K(+) current (IKACh), transient outward K(+) current (Ito) and ultra-rapid delayed rectifier potassium current (IKur) as well as downregulation of protein encoding L-type Ca(2+) current (ICa,L) were found after chronic OSA. Besides abnormal electrical activity, chronic OSA induced apoptosis and interstitial fibrosis of atrial myocytes, which was partly mediated by caspase 9, phosphorylation of extracellular-regulated kinase 1/2, and α-smooth muscle actin. In addition, atrial sympathetic and parasympathetic hyperinnervation were found manifesting by enhanced growth-associated protein 43, tyrosine hydroxylase and elevated choline acetyltransferase. Moreover, protein expression of β1, β2, and M2 receptor were markedly increased by chronic OSA. In summary, we firstly demonstrated in canine model that chronic OSA could shorten AERP and lead to altered expression of important channel proteins, moreover, induce atrial structure remodeling by increased atrial apoptosis, fibrosis, and autonomic remodeling, eventually promoting the development of a substrate of AF. Our findings suggested that reversing atrial remodeling might be a potential therapeutic strategy for OSA-induced AF.