miR-874-3p Is Identified as a Biomarker for Acute Kidney Injury and Mediates Disease Development via Targeting MSRB3.

Introduction: Acute kidney injury (AKI) is a common clinical disease, especially in the intensive care unit. Identification of reliable biomarker is of great clinical significance and benefit the therapy and prevention of AKI. The clinical significance and function of miR-874-3p in AKI development were evaluated in this study aiming to explore a novel biomarker for AKI.

Methods: There were 83 AKI patients and 56 healthy individuals included, and the serum samples were collected. The AKI animal models were established via ischemic/reperfusion (I/R) and LPS on C57BL/6 mice. The expression of miR-874-3p was evaluated using PCR, while the potential downstream targets were also validated in AKI mice. The regulatory mechanism of miR-874-3p was investigated in AKI cell model established with HK-2 cell by I/R.

Results: miR-874-3p was downregulated in both AKI patients and established AKI mice models. The downregulation of miR-874-3p could discriminate against AKI patients and predict poor prognosis of patients. miR-874-3p was negatively correlated with the levels of serum creatine, blood urea nitrogen, CRP, NEU, and PCT and positively correlated with the eGFR of AKI patients. In I/R- and LPS-induced AKI mice, overexpressing miR-874-3p could alleviate renal dysfunction, oxidative stress, and inflammation induced by AKI. Additionally, miR-874-3p could negatively regulate the expression of MSRB3, which was speculated as the potential mechanism underlying the function of miR-874-3p in AKI. Overexpression of miR-874-3p could alleviate the I/R-induced HK-2 cell apoptosis and decreased proliferation, which was reversed by the upregulation of MSRB3.

Conclusion: miR-874-3p served as a diagnostic and prognostic biomarker of AKI and mediate the severity and development of AKI via targeting MSRB3.