Overexpression of NR4A2 alleviates renal and myocardial injury in diabetes nephropathy rats through the HDAC11/SPRY1 pathway

Background: Background: Diabetic nephropathy (DN) remains the most prevalent cause of end-stage renal disease. Nuclear receptor subfamily 4 group A member 2 (NR4A2) is a nuclear receptor with unique physiological characteristics. Objective: This study explored the molecular mechanism of NR4A2 in renal and cardiac functions of DN rats. Methods: A rat model of DN was established by intraperitoneal injection of streptozocin. NR4A2, histone deacetylase 11 (HDAC11), and sprouty 1 (SPRY1) expressions were detected. The fasting blood glucose (FBG), urinary albumin (UAlb), serum creatinine (Cr), and blood urea nitrogen (BUN) were determined. The pathological injury of renal and myocardial tissues was evaluated. The mitral early to late diastolic flow velocity ratio (E/A ratio), left ventricular ejection fraction (LVEF), left ventricular systolic function (LVSF), left ventricular internal dimension systole (LVIDs), and left ventricular internal diameter diastole (LVIDd) were tested, and the levels of serum cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) were examined. The enrichment of NR4A2 in HDAC11 promoter and enrichment of H3K27 acetylation in SPRY1 promoter were measured. Results: NR4A2 and SPRY1 were downregulated while HDAC11 was upregulated in renal and myocardial tissues of DN rats. NR4A2 overexpression reduced FBG, UAlb, Cr, and BUN, alleviated pathological injury of renal and myocardial tissues, elevated the E/A ratio, LVEF, and LVFS, but reduced LVIDs, and decreased serum cTnI and CK-MB. NR4A2 depressed HDAC11 expression by binding to the HDAC11 promoter. HDAC11 repressed SPRY1 transcription by suppressing the H3K27ac level. HDAC11 overexpression or SPRY1 inhibition reversed the alleviating effect of NR4A2 overexpression on DN rats. Conclusion: NR4A2 was poorly expressed in DN rats. NR4A2 overexpression suppressed HDAC11 expression by binding to the HDAC11 promoter and enhanced SPRY1 transcription by enhancing H3K27 acetylation, thereby alleviating the renal and myocardial injury of DN rats.