DiDang Tang Inhibits Endoplasmic Reticulum Stress-Mediated Apoptosis Induced by Oxygen Glucose Deprivation and Intracerebral Hemorrhage Through Blockade of the GRP78-IRE1/PERK Pathways.

Qingxia Huang,Xiangyan Li,Jian Wang,Tianye Lan,Dongmei Zhang,Tingting Lou,Liwei Sun,Jing Lu,Jixiang Ren,Peng Xu,Daqing Zhao,He Zhang

doi:10.3389/fphar.2018.01423

Abstract

DiDang Tang (DDT), a Chinese traditional medicine formula, contains 4 Chinese traditional medicine substances, has been widely used to treat intracerebral hemorrhage (ICH) patients. However, the molecular mechanisms of DDT for protecting neurons from oxygen and glucose deprivation (OGD)-induced endoplasmic reticulum (ER) stress and apoptosis after ICH still remains elusive. In this study, high-performance liquid chromatography fingerprint analysis was performed to learn the features of the chemical compositions of DDT. OGD-induced ER stress, Ca2+ overload, and mitochondrial apoptosis were investigated in nerve growth factor -induced PC12, primary neuronal cells, and ICH rats to evaluate the protective effect of DDT. We found that DDT treatment protected neurons against OGD-induced damage and apoptosis by increasing cell viability and reducing the release of lactate dehydrogenase. DDT decreased OGD-induced Ca2+ overload and ER stress through the blockade of the glucose-regulated protein 78 (GRP78)- inositol-requiring protein 1α (IRE1)/ protein kinase RNA-like ER kinase (PERK) pathways and also inhibited apoptosis by decreasing mitochondrial damage. Moreover, we observed similar findings when we studied DDT for inhibition of ER stress in a rat model of ICH. In addition, our experiments further confirmed the neuroprotective potential of DDT against tunicamycin (TM)-induced neural damage. Our in vitro and in vivo results indicated that the neuroprotective effect of DDT against ER stress damage and apoptosis occurred mainly by blocking the GPR78-IRE1/PERK pathways. Taken together, it provides reliable experimental evidence and explains the molecular mechanism of DDT for the treatment of patients with ICH.

Highlights

Oxygen and glucose deprivation (OGD) of the neurons surrounding a hematoma has been considered a major factor in neuronal cell death in acute and chronic intracerebral hemorrhage (ICH) (Chien et al, 2015; Selim and Sheth, 2015; Korompoki et al, 2017)
We investigate the protective effect of DDT on oxygen and glucose deprivation (OGD)-induced endoplasmic reticulum (ER) stress, Ca2+ overload, and mitochondrial apoptosis and reveal the molecular mechanism of DDT on blocking glucose-regulated protein 78 (GRP78)- inositol-requiring protein 1α (IRE1)/protein kinase RNA-like ER kinase (PERK) pathways in PC12 and primary neuronal cell models of ER stress and apoptosis induced by OGD or tunicamycin (TM), an ER stress inducer, and in a rat model of ICH, which we call the ICH rat
To further confirm the time of OGD incubation in PC12 cell apoptosis, we examined the expression of apoptosis-related proteins, such as Bcl-2, Bax and Cytochrome C (Cyto C), a mitochondrial dysfunction marker

Summary

Introduction

Oxygen and glucose deprivation (OGD) of the neurons surrounding a hematoma has been considered a major factor in neuronal cell death in acute and chronic intracerebral hemorrhage (ICH) (Chien et al, 2015; Selim and Sheth, 2015; Korompoki et al, 2017). Increasing evidences has shown that under OGD after ICH, protein misfolding and accumulation in the endoplasmic reticulum (ER) lumen initiate ER stress (Cominacini et al, 2015) and lead to mitochondrial apoptosis (Yuan et al, 2017). The suppression of ER stress-mediated apoptosis could be a potential and effective strategy for the treatment of ICH (Zhang et al, 2015). External environment changes, such as energy deprivation, cause the accumulation of misfolded proteins in the ER lumen (Zhong et al, 2013). We speculate that OGD after ICH leads to neuronal apoptosis by triggering ER stress and Ca2+ overload

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Conclusion