Down-regulation of GRP78 alleviates lipopolysaccharide-induced acute kidney injury

Abstract

Purpose: Acute kidney injury (AKI) is accompanied with life-threatening sepsis. It is necessary to develop effective therapy agent or strategy for treating AKI. LPS is a primary pathogenic factor that induces sepsis. Glucose-regulated protein 78 (GRP78) is closely related to cell injuries. The objective of this study was to examine the role of GRP78 in LPS-induced AKI.

Methods: Cell counting kit-8 (CCK-8) assay and flow cytometry (FCM) were respectively performed to assess the cell viability and apoptosis. Available commercial kits were used to detect the reactive oxygen species (ROS) contents and the activity of oxidative indicators. The expressions of the relevant factors were determined by real-time PCR (RT-PCR) and Western blot.

Results: The results showed that the expression of GRP78 was apparently increased by LPS treatment, and that the down-regulation of GRP78 by small RNA interference improved the proliferation ability of renal cells in comparison to LPS group. The LPS-induced immune response and oxidative stress was alleviated by the depletion of GRP78. Moreover, the LPS-induced apoptosis was reduced in the GRP78 group by regulating the expression of mitochondrial apoptosis (Bcl-2, Bax) and endoplasmic reticulum (ER) stress (CHOP, caspase-12)-associated proteins. In addition, the protective role of GRP78 reduction was partly related to the balance of NF-κB/IκB.

Conclusions: Down-regulation of GRP78 attenuated LPS-induced AKI through inhibiting immune response/oxidative stress-associated apoptosis.

Keywords: Aacute kidney injury; FCM; GRP78; Lipopolysaccharide.