Analysis of glucocorticoid receptor and microRNAs expression in pathological renal tissues

Glucocorticoid receptor (GR) is expressed in normal renal podocytes; however, its expression differs among renal diseases. The expression of GR as well as its epigenetic regulators microRNA (miR)30a, miR24 and miR370 was studied in the renal tissues of patients with systemic lupus nephritis (LN), minimal changes disease (MCD) and pauci-immune glumeronephritis (PIN). A total of 51 patients undergoing renal biopsy and 22 nephrectomised controls with no history of parenchymal renal disease were recruited from the Clinic of Nephrology and Renal Transplantation of General Laikon hospital between November 2016 and March 2019. All patients were newly-diagnosed and they were naïve of any treatment. The mRNA and protein expression were analyzed through reverse transcription-quantitative PCR and immunohistochemistry respectively. Written consent was obtained from all participants. GR mRNA expression was significantly reduced in all pathological samples compared with the 'normal' renal tissues used as controls (P=0.023 for LN, P=0.05 for MCD and P=0.004 for PIN). Similarly, GR protein expression was lower in all pathological samples (>6 GR positive podocytes/glomerulus in 50% of patients with LN and MCD and 18% with PIN) compared with controls (>6 positive podocytes/glomerulus in all the controls). PIN samples presented significantly lower GR mRNA and protein expression compared with LN and MCD samples. No significant differences were observed in the miR30a expression when comparing pathological with 'normal' renal samples. miR24 and miR370 expression demonstrated statistically significant difference in all pathological compared with 'normal' tissues. Moreover, GR expression was not significantly associated with either LN disease activity score or the response to the treatment. GR and miR24 expression was significantly reduced whereas miR370 significantly increased in all pathological compared with 'normal' renal tissues implying their protentional role in nephritis pathogenesis and treatment. Analysis of larger samples are required for more robust statistical analysis.