[High STING expression exacerbates renal ischemia-reperfusion injury in mice by regulating the TLR4/NF-κB/NLRP3 pathway and promoting inflammation and apoptosis].

Abstract

Objective: To investigate renal expression level of STING in mice with renal ischemia-reperfusion injury (IRI) and its regulatory role in IRI.

Methods: C57BL/6 mice were divided into sham operation group, IRI (induced by clamping the renal artery) model group, IRI+DMSO treatment group, and IRI+SN-011 treatment group. Serum creatinine and blood urea nitrogen of the mice were analyzed, and pathological changes in the renal tissue were assessed with PAS staining. RT-qPCR, ELISA, Western blotting, and immunohistochemistry were used to detect the expression levels of STING, KIM-1, Bcl-2, Bax, caspase-3, TLR4, P65, NLRP3, caspase-1, CD68, MPO, IL-1β, IL-6, and TNF-α in the renal tissues. In the cell experiment, HK-2 cells exposed to hypoxia-reoxygenation (H/R) were treated with DMSO or SN-011, and cellular STING expression levels and cell apoptosis were analyzed using RT-qPCR, Western blotting or flow cytometry.

Results: In C57BL/6 mice, renal IRI induced obvious renal tissue damage, elevation of serum creatinine and blood urea nitrogen levels and renal expression levels of KIM-1, STING, TLR4, P65, NLRP3, caspase-1, caspase-3, Bax, CD68, MPO, IL-1β, IL-6, and TNF-α, and reduction of Bcl-2 expression level. Treatment of the mouse models with SN-011 for inhibiting STING expression significantly alleviated these changes. In HK-2 cells, H/R exposure caused significant elevation of cellular STING expression and obviously increased cell apoptosis rate, which was significantly lowered by treatment with SN-011.

Conclusion: Renal STING expression is elevated in mice with renal IRI to exacerbate renal injury by regulating the TLR4/NF-κB/NLRP3 pathway and promoting inflammation and apoptosis in the renal tissues.