Background/Aims: Acute myocardial infarction (AMI) is one of the leading causes of death in the world. However, specific diagnostic biomarkers have not been fully determined, and candidate regulatory targets for AMI have not been identified to date. Long noncoding RNAs (lncRNAs) are a class of RNA molecules that have diverse regulatory functions during embryonic development, normal life, and disease in higher organisms. However, research on the role of lncRNAs in cardiovascular diseases, particularly AMI, is still in its infancy. HOX antisense intergenic RNA (HOTAIR), a 2.2 kb lncRNA, was initially described as a modulator of HOX gene expression. Recent studies have illustrated the important role of HOTAIR in cancer progression, but few studies have reported its function in cardiac disease, including AMI. In the current study, we aimed to detect the expression of HOTAIR during AMI and to explore its function in hypoxia-induced cardiomyocyte injury in neonatal cardiomyocytes. Methods: In 50 consecutively enrolled AMI patients, we examined the serum expression levels of HOTAIR and analysed its correlation with cardiac troponin I (cTnI) expression. Another 50 age- and sex-matched subjects served as healthy controls. Next, the HOTAIR expression was detected in the serum from C57BL/6J mice subjected to coronary artery ligation and in neonatal rat cardiomyocytes induced by hypoxia. Cultured cardiomyocytes apoptosis were measured by terminal deoxynucleotide transferase dUTP nick end labelling (TUNEL) staining. A search for miRNAs that had complementary base paring with HOTAIR was performed utilizing an online software program, and the interaction between miR-1 and HOTAIR was examined using a luciferase reporter assay. Results: Our study revealed that HOTAIR expression was significantly decreased in the serum of AMI patients compared with that of the healthy controls. Similarly, we observed that HOTAIR was downregulated in the serum of mice subjected to coronary artery ligation and in cultured cardiomyocytes exposed to hypoxia. Furthermore, we observed that the adenovirus vector-driven overexpression of HOTAIR dramatically limited hypoxia-induced myocyte apoptosis, whereas knockdown HOTAIR by AdshHOTAIR (adenoviral short hairpin HOTAIR) exhibited the opposite phenotype. Mechanistically, we discovered that the cardioprotective function of HOTAIR is partly based on the negative regulation of miR-1. Conclusions: Taken together, the results of our study suggest that HOTAIR is a protective factor for cardiomyocytes and that the plasma concentration of HOTAIR may serve as a biomarker for human AMI diagnosis.

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide. Due to the growing economic burden of NAFLD on public health, it has become an emergent target for clinical intervention. DUSP12 is a member of the dual specificity phosphatase (DUSP) family, which plays important roles in brown adipocyte differentiation, microbial infection, and cardiac hypertrophy. However, the role of DUSP12 in NAFLD has yet to be clarified. Here, we reveal that DUSP12 protects against hepatic steatosis and inflammation in L02 cells after palmitic acid/oleic acid treatment. We demonstrate that hepatocyte specific DUSP12-deficient mice exhibit high-fat diet (HFD)-induced and high-fat high-cholesterol diet-induced hyperinsulinemia and liver steatosis and decreased insulin sensitivity. Consistently, DUSP12 overexpression in hepatocyte could reduce HFDinduced hepatic steatosis, insulin resistance, and inflammation. At the molecular level, steatosis in the absence of DUSP12 was characterized by elevated apoptosis signal-regulating kinase 1 (ASK1), which mediates the mitogenactivated protein kinase (MAPK) pathway and hepatic metabolism. DUSP12 physically binds to ASK1, promotes its dephosphorylation, and inhibits its action on ASK1-related proteins, JUN N-terminal kinase, and p38 MAPK in order to inhibit lipogenesis under high-fat conditions. Conclusion: DUSP12 acts as a positive regulator in hepatic steatosis and offers potential therapeutic opportunities for NAFLD. (Hepatology 2019;70:1099-1118). SEE EDITORIAL ON PAGE 1091N onalcoholic fatty liver disease (NAFLD) is the most common diffuse liver disease and is characterized by lipid accumulation in hepatocytes in the absence of excessive alcohol consumption. (1) The prevalence of NAFLD increases worryingly with obesity and other diseases of metabolic syndrome (MS) and is expected to be the leading cause of liver failure in the future. (2) Accumulating studies show that NAFLD not only is linked to an increased risk of liver-related mortality or morbidity

Isorhamnetin, a flavonoid compound extracted from the Chinese herb Hippophae rhamnoides L., is well known for its anti-inflammatory, anti-oxidative, anti-adipogenic, anti-proliferative, and anti-tumor activities. However, the role of isorhamnetin in cardiac hypertrophy has not been reported. The aims of the present study were to find whether isorhamnetin could alleviate cardiac hypertrophy and to define the underlying molecular mechanisms. Here, we investigated the effects of isorhamnetin (100 mg/kg/day) on cardiac hypertrophy induced by aortic banding in mice. Cardiac hypertrophy was evaluated by echocardiographic, hemodynamic, pathological, and molecular analyses. Our data demonstrated that isorhamnetin could inhibit cardiac hypertrophy and fibrosis 8 weeks after aortic banding. The results further revealed that the effect of isorhamnetin on cardiac hypertrophy was mediated by blocking the activation of phosphatidylinositol 3-kinase-AKT signaling pathway. In vitro studies performed in neonatal rat cardiomyocytes confirmed that isorhamnetin could attenuate cardiomyocyte hypertrophy induced by angiotensin II, which was associated with phosphatidylinositol 3-kinase-AKT signaling pathway. In conclusion, these data indicate for the first time that isorhamnetin has protective potential for targeting cardiac hypertrophy by blocking the phosphatidylinositol 3-kinase-AKT signaling pathway. Thus, our study suggests that isorhamnetin may represent a potential therapeutic strategy for the treatment of cardiac hypertrophy and heart failure.

Diabetes contributes to cardiovascular complications and the pathogenesis of cardiac remodeling that can lead to heart failure. We aimed to evaluate the functional role of LAZ3 in diabetic cardiomyopathy (DCM). Streptozotocin (STZ) was used to induce a diabetic mouse model. Three months after induction, the mice were subjected to retro-orbital venous plexus injection of adeno-associated virus 9 (AAV9) that overexpressed LAZ3. Six weeks after the infection, mouse hearts were removed to assess the degree of cardiac remodeling. LAZ3 was down-regulated in the diabetic mouse hearts and high glucose stimulated cardiomyocytes. Knock-down of LAZ3 in cardiomyocytes with LAZ3 siRNA reduced cell viability, increased the inflammatory response and induced oxidative stress and cell apoptosis. Overexpression of LAZ3 by infection with adeno-associated virus (AAV9)-LAZ3 protected against an inflammatory response, oxidative stress and cell apoptosis in both a high glucose stimulated in vitro study and diabetic mouse hearts. We found that LAZ3 increased the activation of PPARa, which increased PGC-1a activation and subsequently augmented NRF2 expression and nuclear translocation. This outcome was confirmed by NRF2 siRNA and a PPARa activator, since NRF2 siRNA abrogated the protective effects of LAZ3 overexpression, while the PPARa activator reversed the deteriorating phenotype of LAZ3 knock-down in both the in vitro and vivo study. Furthermore, LAZ3 decreased miR-21 expression, which resulted in PPARa activation, NRF2 expression and nuclear translocation. In conclusion, LAZ3 protects against cardiac remodeling in DCM by decreasing miR-21, thus regulating PPARa/NRF2 signaling.

Background/Aims: Vascular smooth muscle cell (VSMC) hyperplasia plays important roles in the pathogenesis of many vascular diseases, such as atherosclerosis and restenosis. Many microRNAs (miRs) have recently been reported to regulate the proliferation and migration of VSMC. In the current study, we aimed to explore the function of miR-93 in VSMCs and its molecular mechanism.Methods: First, qRT-PCR and immunofluorescence assays were performed to determine miR-93 expression in rat VSMCs following carotid artery injury in vivo and platelet-derived growth factor-BB (PDGF-BB) stimulation in vitro. Next, the biological role of miR-93 in rat VSMC proliferation and migration was examined in vivo and vitro. EdU incorporation assay and MTT assay for measuring cell proliferation, Transwell cell invasion assay and Cell scratch wound assay for measuring cell migration. Then, the targets of miR-93 were identified. Finally, the expression levels of proteins in the Raf-ERK1/2 pathway were measured by western blot.Results: MiR-93 was upregulated in rat VSMCs following carotid artery injury in vivo. Similar results were observed in ex vivo cultured VSMCs after PDGF-BB treatment. MiR-93 inhibition suppressed neointimal formation after carotid artery injury. Moreover, our results demonstrated that a miR-93 inhibitor suppressed the PDGF-BB induced proliferation and migration of in VSMC. This inhibitor also decreased the expression levels of MMP2 and cyclin D1. Mechanistically, we discovered that mitofusin 2(Mfn2) is a direct target of miR-93. Furthermore, an analysis of the signaling events revealed that miR-93-mediated VSMC proliferation and migration occurred via the Raf-ERK1/2 pathway.Conclusions: Our findings suggest that miR-93 promotes VSMCs proliferation and migration by targeting Mfn2. MiR-93 may be a new target for treating in-stent restenosis.