High-Salt Diet Aggravates Endothelial-to-Mesenchymal Transition in Glomerular Fibrosis in Dahl Salt-Sensitive Rats.

BACKGROUND: Both diabetic and hypertensive nephropathy eventually progress to glomerulosclerosis. Previous studies revealed a potential role of endothelial-to-mesenchymal transition (EndMT) in the pathophysiology of glomerulosclerosis in diabetic rats. Therefore, we hypothesized that EndMT was also involved in the development of glomerulosclerosis in salt-sensitive hypertension. We aimed to explore the effects of high-salt diet on endothelial-to-mesenchymal transition (EndMT) in glomerulosclerosis in Dahl salt-sensitive (Dahl-SS) rats. METHODS: Eight-week-old male rats were fed high-salt (8%NaCl; DSH group) or normal salt (0.3%NaCl; DSN group) for eight weeks, with systolic blood pressure (SBP), serum creatinine, urea, 24-hour urinary protein/sodium, renal interlobar artery blood flow, and pathological examination measured. We also examined endothelial-(CD31) and fibrosis-related protein(α-SMA) expressions in glomeruli. RESULTS: High-salt diet increased SBP (DSH vs. DSN, 205.2 ±â€…8.9 vs. 135.4 ±â€…7.9 mm Hg, P < 0.01), 24-hour urinary protein (132.55 ±â€…11.75 vs. 23.52 ±â€…5.94 mg/day, P < 0.05), urine sodium excretions (14.09 ±â€…1.49 vs. 0.47 ±â€…0.06 mmol/day, P < 0.05), and renal interlobar artery resistance. Glomerulosclerosis increased (26.1 ±â€…4.6 vs. 7.3 ±â€…1.6%, P < 0.05), glomerular CD31 expressions decreased while α-SMA expression increased in DSH group. Immunofluorescence staining showed that CD31 and α-SMA co-expressed in glomeruli of the DSH group. The degree of glomerulosclerosis negatively correlated with CD31 expressions (r = -0.823, P < 0.01) but positively correlated with α-SMA expressions (r = 0.936, P < 0.01). CONCLUSIONS: We demonstrated that a high-salt diet led to glomerulosclerosis involving the EndMT process, which played an essential role in glomerulosclerosis in hypertensive Dahl-SS rats.

Circ_0124644 Serves as a ceRNA for miR-590-3p to Promote Hypoxia-Induced Cardiomyocytes Injury via Regulating SOX4.

Circular RNA (circRNA) is an important factor for regulating the progression of many cardiovascular diseases, including acute myocardial infarction (AMI). However, the role of circ_0124644 in AMI progression remains unclear. Hypoxia was used to induce cardiomyocytes injury. The expression of circ_0124644, microRNA (miR)-590-3p, and SRY-box transcription factor 4 (SOX4) mRNA was measured by qRT-PCR. Cell counting kit 8 (CCK8) assay and flow cytometry were utilized to detect cell viability, cell cycle progression, and apoptosis. The protein levels of apoptosis markers and SOX4 were determined by western blot (WB) analysis, and the levels of oxidative stress markers were assessed using commercial Assay Kits. Dual-luciferase reporter assay, RIP assay, and RNA pull-down assay were employed to confirm the interaction between miR-590-3p and circ_0124644 or SOX4. Circ_0124644 was upregulated in AMI patients and hypoxia-induced cardiomyocytes. Hypoxia could inhibit cardiomyocytes viability, cell cycle process, and promote apoptosis and oxidative stress, while silencing circ_0124644 could alleviate hypoxia-induced cardiomyocytes injury. In terms of mechanism, circ_0124644 could target miR-590-3p. MiR-590-3p overexpression could relieve hypoxia-induced cardiomyocytes injury. Also, the suppressive effect of circ_0124644 knockdown on hypoxia-induced cardiomyocytes injury could be reversed by miR-590-3p inhibitor. Moreover, SOX4 was found to be a target of miR-590-3p, and its overexpression also could reverse the regulation of miR-590-3p on hypoxia-induced cardiomyocytes injury. Circ_0124644 silencing could alleviate hypoxia-induced cardiomyocytes injury by regulating the miR-590-3p/SOX4 axis, suggesting that it might be a target for alleviating AMI.

Oxidized low-density lipoprotein accelerates the injury of endothelial cells via circ-USP36/miR-98-5p/VCAM1 axis.

Circular RNAs (circRNAs) are a group of RNAs featured by a covalently closed continuous loop structure. This study aimed to uncover the function and mechanism of circ-ubiquitin specific peptidase 36 (USP36) in endothelial cells treated with oxidized low-density lipoprotein (ox-LDL). The levels of circ-USP36, microRNA-98-5p (miR-98-5p) and vascular cell adhesion molecule 1 (VCAM1) were examined by a quantitative real-time polymerase chain reaction (qRT-PCR). The viability, apoptosis and inflammation were detected by (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. Western blot assay was performed to detect the expression of apoptosis and proliferation-related markers and VCAM1 protein level. The targets of circ-USP36 and miR-98-5p were searched using starBase website, and dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were applied to validate the above predictions. Ox-LDL exposure induced the upregulation of circ-USP36 in HUVEC cells. Circ-USP36 accelerated ox-LDL-induced apoptosis, inflammatory and viability inhibition of HUVEC cells. MiR-98-5p was a direct downstream gene of circ-USP36. Circ-USP36 promoted the injury of ox-LDL-induced HUVEC cells through targeting miR-98-5p. VCAM1 could bind to miR-98-5p, and the protective effects of miR-98-5p accumulation on ox-LDL-induced HUVEC cells were reversed by the transfection of VCAM1. VCAM1 was regulated by circ-USP36/miR-98-5p signaling in HUVEC cells. Ox-LDL promoted the apoptosis and inflammation but suppressed the viability of HUVEC cells through upregulating circ-USP36, thus elevating the expression of VCAM1 via miR-98-5p.