Tat-HSP22 inhibits oxidative stress-induced hippocampal neuronal cell death by regulation of the mitochondrial pathway

Hyo Sang Jo,Duk-Soo Kim,Sung-Woo Cho,Jung Hwan Park,Yeon Hee Yu,Min Jea Shin,Dae Won Kim,Soo Young Choi,Ora Son,Won Sik Eum,Hyeon Ji Yeo,Eun Ji Yeo,Yeon Joo Choi,Keun Wook Lee,Su Bin Cho,Jinseu Park,Chi Hern Lee,Eun Jeong Sohn

doi:10.1186/s13041-016-0281-8

Abstract

Oxidative stress plays an important role in the progression of various neuronal diseases including ischemia. Heat shock protein 22 (HSP22) is known to protect cells against oxidative stress. However, the protective effects and mechanisms of HSP22 in hippocampal neuronal cells under oxidative stress remain unknown. In this study, we determined whether HSP22 protects against hydrogen peroxide (H2O2)-induced oxidative stress in HT-22 using Tat-HSP22 fusion protein. We found that Tat-HSP22 transduced into HT-22 cells and that H2O2-induced cell death, oxidative stress, and DNA damage were significantly reduced by Tat-HSP22. In addition, Tat-HSP22 markedly inhibited H2O2-induced mitochondrial membrane potential, cytochrome c release, cleaved caspase-3, and Bax expression levels, while Bcl-2 expression levels were increased in HT-22 cells. Further, we showed that Tat-HSP22 transduced into animal brain and inhibited cleaved-caspase-3 expression levels as well as significantly inhibited hippocampal neuronal cell death in the CA1 region of animals in the ischemic animal model. In the present study, we demonstrated that transduced Tat-HSP22 attenuates oxidative stress-induced hippocampal neuronal cell death through the mitochondrial signaling pathway and plays a crucial role in inhibiting neuronal cell death, suggesting that Tat-HSP22 protein may be used to prevent oxidative stress-related brain diseases including ischemia.

Highlights

Heat shock proteins (HSPs) are known to be stressinducible proteins and are found in all organism
The produced gene was digested with restriction enzymes (Xho I and Bam HI) and the gene was cloned into a Tat expression vector to produce cell permeable Tat-Heat shock protein 22 (HSP22) protein
SDS-PAGE and Western blot analysis using an anti-histidine antibody showed that purified Tat-HSP22 and control HSP22 protein bands correspond with the expected molecular weight of HSP22 protein (Fig. 1b and c)

Summary

Introduction

Heat shock proteins (HSPs) are known to be stressinducible proteins and are found in all organism. They play an important role in cell survival in cells exposed to biological stresses such as oxidative stress or chemical stress [1,2,3]. Small HSPs are highly conserved and well characterized as playing the role of molecular chaperones, and having a protective function against biological stress [4,5,6,7]. The mitochondria play an important role in multiple cellular processes including apoptosis [14]. The exact biological function and precise mechanism of HSP22 protein in ischemic neuronal damage remains poorly understood

Methods

Results

Conclusion