MiR-133a alleviates renal injury caused by sepsis by targeting BNIP3L

Objective: Sepsis is an important cause of acute kidney injury (AKI), seriously jeopardizing the health of patients. This paper's aim was to investigate whether microRNA-133a had a protective effect on sepsis-induced kidney injury.

Materials and methods: We established a kidney injury model with lipopolysaccharide (LPS) and divided TCMK-1 cells into 4 groups: control group (con); LPS treatment group; LPS + negative control (NC) treatment group; LPS + miR-133a mimic (mim) group. The expressions of miR-133a, TNF-α mRNA, IL-6 mRNA, Bax mRNA, Bcl-2 mRNA, BNIP3L mRNA, IκKα mRNA and IκB-α mRNA were detected by PCR. Western blot was used to detect the protein expression of TNF-α, IL-6, Bax, Bcl-2, BNIP3L, IκKα and IκB-α. Cell viability was measured by cell counting kit-8 (CCK-8). Flow cytometry was utilized to detect Apoptosis rate. IL-1β immunofluorescence and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining were used to observe the inflammation and Apoptosis in TCMK-1 cells.

Results: The miR-133a expression was decreased in TCMK-1 cells treated with LPS. In the LPS treatment group, the expression of TNF-α, IL-6, Bax, BNIP3L and IκKα increased, and the expression of Bcl-2 and IκB-α decreased. When overexpressing miR-133a, the protein and mRNA expression of TNF-α, IL-6, Bax, BNIP3L and IκKα decreased markedly, while the expression of Bcl-2 and IκB-α increased markedly. Compared with the LPS-treated group, the apoptotic rate, the number of TUNEL-positive cells, and the immunofluorescence intensity of IL-1β in LPS+mim group were greatly decreased.

Conclusions: The miR-133a expression was decreased in TCMK-1 cells treated by LPS and miR-133a can inhibit inflammation and Apoptosis of TCMK-1 cells induced by LPS by targeting BNIP3L via inhibiting NF-κB pathway.