MiR-593-5p promotes the development of hypoxic-induced pulmonary hypertension via targeting PLK1.

OBJECTIVE: The aim of this study was to investigate the role of microRNA-593-5p (miR-593-5p) in hypoxia-induced pulmonary hypertension (HPH), and to explore its underlying mechanism. MATERIALS AND METHODS: Sprague-Dawley (SD) rats were housed in a hypoxia environment 8 hours per day for consecutive 4 weeks. After the establishment of the HPH rat model, we detected the right ventricular systolic pressure (RVSP) and right heart hypertrophy index (RVHI) in HPH rats and controls. The expression levels of miR-593-5p and polo-like kinase 1 (PLK1) in rat lungs were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Subsequently, miR-593-5p mimics and inhibitor were constructed and transfected into cells. The proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) were accessed by cell counting kit-8 (CCK-8) assay and wound healing assay, respectively. The protein level of PLK1 in PASMCs after transfection with miR-593-5p mimics or inhibitor was detected by Western blot. Dual-luciferase reporter gene assay was conducted to verify the binding condition of miR-593-5p and PLK1. Finally, rescue experiments were performed to explore whether the regulatory effect of miR-593-5p on HPH development was associated with PLK1. RESULTS: RVSP and RVHI in rats of the hypoxic group were significantly higher than those of controls. MiR-593-5p was significantly downregulated while PLK1 was remarkably upregulated in lung tissues of HPH rats than those of controls. Similarly, miR-593-5p expression in PASMCs decreased gradually with the prolongation of hypoxia induction. Overexpression of miR-593-5p remarkably inhibited the proliferation and migration of PASMCs. Subsequently, dual-luciferase reporter gene verified the binding condition of miR-593-5p and PLK1. Both the mRNA and protein levels of PLK1 were negatively regulated by miR-593-5p. Also, rescue experiments demonstrated that the inhibitory effects of miR-593-5p on the proliferation and migration of PASMCs could be reversed by PLK1 overexpression. CONCLUSIONS: MiR-593-5p is lowly expressed in lung tissues of HPH rats. Meanwhile, it stimulates the proliferation and migration of PASMCs via targeting PLK1, thereby promoting HPH development.

Association study between polymorphisms in selenoprotein genes and susceptibility to Kashin-Beck disease.

OBJECTIVES: Kashin-Beck disease (KBD) is a disabling osteoarthropathy involving growth cartilage endemic to selenium (Se)-deficient regions in China. Associations between genetic variation in selenoprotein genes and susceptibility to many diseases have recently been investigated but few studies have been performed on KBD. We found four genetic polymorphisms in selenoprotein genes and assessed their association with increased susceptibility to KBD. METHODS: Four polymorphisms including GPX1 (rs1050450), TrxR2 (rs5748469), SEPP1 (rs7579) and DIO2 (rs225014) were analyzed for 161 KBD patients and 312 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or tetra-primer amplification refractory mutation system PCR (Tetra-primer ARMS PCR). Glutathione peroxidase (GPX) activity in whole blood was measured using a GPX assay kit. The mRNA expression of GPX1, nuclear factor-kappaB (NF-kappaB) p65 and p53 in both whole blood and articular cartilage tissue were detected using Real-Time PCR. RESULTS: The genotypic and allelic frequency of GPX1 Pro198Leu was significantly different between KBD patients and controls (P=0.013, P=0.037). A significant increased KBD risk was observed in individuals with Pro/Leu or Leu/Leu (odds ratio=1.781; 95% confidence interval: 1.127-2.814) compared with Pro/Pro. No association was observed between the other three single nucleotide polymorphisms (SNPs) and KBD risk. In addition, GPX enzyme activity in whole blood was lower in the KBD group (P<0.01), and the GPX activity in whole blood decreased significantly in a subgroup of individuals representing Pro/Leu and Leu/Leu compared to Pro/Pro (P<0.01). In whole blood and articular cartilage tissue samples of KBD patients, GPX1 and NF-kappaB p65 mRNA levels were lower (P<0.01) while p53 levels were higher (P<0.001). CONCLUSION: GPX1 Pro198Leu is a potential genetic risk factor in the development of KBD and the GPX1 Leu allele is significantly associated with higher KBD risk among the Chinese Han population and with lower GPX enzyme activity. The expression of apoptosis related molecules in KBD patients significantly differs from controls.