Background
Inflammation and apoptosis contribute to the development of sepsis-induced acute kidney injury. Annexin A1 (ANXA1) is the calcium-dependent phospholipid-binding protein known to play an important role in a variety of cellular functions, including inflammation, apoptosis, migration and proliferation. However, the effect of ANXA1 on sepsis-induced acute injury has not been reported. Herein, we investigated the role and underlying mechanism of the mimetic peptide Ac2-26 of annexin A1 in sepsis-induce acute kidney injury in vivo and in vitro.
Methods
In vivo, a mouse model was established by cecal ligation and puncture (CLP), and the Ac2-26 peptide of ANXA1 (1 mg/kg) was intraperitoneally administered 2 hours before CLP. In vitro, A model of HK-2 cells was established by treatment with 10 μg/ml lipopolysaccharide (LPS), and the Ac2-26 peptide of ANXA1 (0.5 μmol/L) was administered 2 hours before LPS. The kidney function of mice detected by Elisa. The kidney tissue was examined by HE and TEM. The inflammatory cytokines and apoptotic molecules were measured by PCR, Elisa, Western blotting and Immunohistochemistry. The apoptosis was detected by TUNEL and flow cytometry.
Results
The studies demonstrated that ANXA1 markedly improved kidney function and kidney tissue injury and enhanced 7-day survival in CLP-induced septic mice, which was accompanied by a significant decrease the inflammatory molecules. ANXA1 obviously downregulated the apoptosis-associated proteins and inhibited apoptosis in kidney tissue in vivo. In vitro studies showed that ANXA1 increased the viability of HK-2 cells, reduced the levels of the inflammatory molecules, downregulated the apoptosis-associated proteins Bax, upregulated the antiapoptotic protein Bcl-2 and inhibited the apoptosis of HK-2 cells.
Conclusions
The mimetic peptide Ac2-26 of annexin A1 protects against sepsis-induced inflammation, apoptosis, and kidney dysfunction via regulating the LXA4/PI3K/IKK-β/NF-κB signaling pathway.