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Endoplasmic Reticulum Stress-Induced Autophagy Provides Cytoprotection from Chemical Hypoxia and Oxidant Injury and Ameliorates Renal Ischemia-Reperfusion Injury.

ABSTRACT: We examined whether endoplasmic reticulum (ER) stress-induced autophagy provides cytoprotection from renal tubular epithelial cell injury due to oxidants and chemical hypoxia in vitro, as well as from ischemia-reperfusion (IR) injury in vivo. We demonstrate that the ER stress inducer tunicamycin triggers an unfolded protein response, upregulates ER chaperone Grp78, and activates the autophagy pathway in renal tubular epithelial cells in culture. Inhibition of ER stress-induced autophagy accelerated caspase-3 activation and cell death suggesting a pro-survival role of ER stress-induced autophagy. Compared to wild-type cells, autophagy-deficient MEFs subjected to ER stress had enhanced caspase-3 activation and cell death, a finding that further supports the cytoprotective role of ER stress-induced autophagy. Induction of autophagy by ER stress markedly afforded cytoprotection from oxidants H2O2 and tert-Butyl hydroperoxide and from chemical hypoxia induced by antimycin A. In contrast, inhibition of ER stress-induced autophagy or autophagy-deficient cells markedly enhanced cell death in response to oxidant injury and chemical hypoxia. In mouse kidney, similarly to renal epithelial cells in culture, tunicamycin triggered ER stress, markedly upregulated Grp78, and activated autophagy without impairing the autophagic flux. In addition, ER stress-induced autophagy markedly ameliorated renal IR injury as evident from significant improvement in renal function and histology. Inhibition of autophagy by chloroquine markedly increased renal IR injury. These studies highlight beneficial impact of ER stress-induced autophagy in renal ischemia-reperfusion injury both in vitro and in vivo.

SUBMITTER: Chandrika BB

PROVIDER: S-EPMC4596863 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Endoplasmic Reticulum Stress-Induced Autophagy Provides Cytoprotection from Chemical Hypoxia and Oxidant Injury and Ameliorates Renal Ischemia-Reperfusion Injury.

Chandrika Bhavya B BB Yang Cheng C Ou Yang Y Feng Xiaoke X Muhoza Djamali D Holmes Alexandrea F AF Theus Sue S Deshmukh Sarika S Haun Randy S RS Kaushal Gur P GP

PloS one 20151007 10

We examined whether endoplasmic reticulum (ER) stress-induced autophagy provides cytoprotection from renal tubular epithelial cell injury due to oxidants and chemical hypoxia in vitro, as well as from ischemia-reperfusion (IR) injury in vivo. We demonstrate that the ER stress inducer tunicamycin triggers an unfolded protein response, upregulates ER chaperone Grp78, and activates the autophagy pathway in renal tubular epithelial cells in culture. Inhibition of ER stress-induced autophagy accelera ...[more]

PMID: 26444017

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Project description:Studies have confirmed a strong association between activation of the endoplasmic reticulum stress pathway and cerebral ischemia/reperfusion (I/R) injury. In this study, three key proteins in the endoplasmic reticulum stress pathway (glucose-regulated protein 78, caspase-12, and C/EBP homologous protein) were selected to examine the potential mechanism of endoplasmic reticulum stress in the neuroprotective effect of G protein-coupled estrogen receptor. Female Sprague-Dawley rats received ovariectomy (OVX), and then cerebral I/R rat models (OVX + I/R) were established by middle cerebral artery occlusion. Immediately after I/R, rat models were injected with 100 μg/kg E2 (OVX + I/R + E2), or 100 μg/kg G protein-coupled estrogen receptor agonist G1 (OVX + I/R + G1) in the lateral ventricle. Longa scoring was used to detect neurobehavioral changes in each group. Infarct volumes were measured by 2,3,5-triphenyltetrazolium chloride staining. Morphological changes in neurons were observed by Nissl staining. Terminal dexynucleotidyl transferase-mediated nick end-labeling staining revealed that compared with the OVX + I/R group, neurological function was remarkably improved, infarct volume was reduced, number of normal Nissl bodies was dramatically increased, and number of apoptotic neurons in the hippocampus was decreased after E2 and G1 intervention. To detect the expression and distribution of endoplasmic reticulum stress-related proteins in the endoplasmic reticulum, caspase-12 distribution and expression were detected by immunofluorescence, and mRNA and protein levels of glucose-regulated protein 78, caspase-12, and C/EBP homologous protein were determined by polymerase chain reaction and western blot assay. The results showed that compared with the OVX + I/R group, E2 and G1 treatment obviously decreased mRNA and protein expression levels of glucose-regulated protein 78, C/EBP homologous protein, and caspase-12. However, the G protein-coupled estrogen receptor antagonist G15 (OVX + I/R + E2 + G15) could eliminate the effect of E2 on cerebral I/R injury. These results confirm that E2 and G protein-coupled estrogen receptor can inhibit the expression of endoplasmic reticulum stress-related proteins and neuronal apoptosis in the hippocampus, thereby improving dysfunction caused by cerebral I/R injury. Every experimental protocol was approved by the Institutional Ethics Review Board at the First Affiliated Hospital of Shihezi University School of Medicine, China (approval No. SHZ A2017-171) on February 27, 2017.

Project description:The aim of the present study was to explore the effect of exogenous hydrogen sulphide (H2S) on endoplasmic reticulum (ER) stress (ERS) in a rat model of hepatic ischemia/reperfusion (I/R) injury. A total of 48 Sprague-Dawley rats were randomly divided into four groups (n=12/group) as follows: Sham, I/R, I/R preceded by NaHS (I/R-NaHS) and I/R preceded by L-C-propargylglycine (PAG), a H2S inhibitor (I/R-PAG). With the exception of the sham group, the rats in the other groups were subjected to 30 min hepatic warm ischemia followed by reperfusion for 6 or 12 h. Hepatic function was evaluated by serum concentrations of alanine aminotransferase (ALT). Apoptosis of hepatic cells was assessed by TUNEL staining and measurement of caspase-12 expression. The expression levels of ERS-associated proteins and mRNAs of pancreatic ER eukaryotic translation initiation factor-2a kinase (PERK), activating transcription factor-6 (ATF6), glucose-regulated protein (GRP) 78, TNF-receptor-associated factor (TRAF)-2, C/EBP homologous protein (CHOP) and caspase-12 were also measured by western blotting and reverse transcription-quantitative PCR. The serum concentrations of ALT in the I/R and I/R-PAG groups were found to be significantly higher compared with those in the sham and I/R-NaHS groups after 6 h of reperfusion; in addition, the ALT level returned to normal in the I/R group, while it increased further in the I/R-PAG group after 12 h of reperfusion. A higher cell apoptosis rate was observed in the I/R and I/R-PAG groups and the highest cell apoptosis rate was observed in the I/R-PAG group; correspondingly, the expression of caspase-12 was increased in the I/R and I/R-PAG groups. H2S appeared to significantly attenuate hepatic I/R-induced ERS response, as indicated by the decreased expression of ATF6, PERK, GRP78, TRAF2 and CHOP. Endogenous H2S may serve a hepatoprotective function after I/R, and inhibition of endogenous H2S results in aggravation of I/R damage. Exogenous H2S was shown to inhibit ERS-related gene expression, leading to suppression of inflammatory reaction and improvement of I/R damage. Therefore, exogenous H2S has therapeutic potential to alleviate hepatic I/R injury.

Dataset Information

Endoplasmic Reticulum Stress-Induced Autophagy Provides Cytoprotection from Chemical Hypoxia and Oxidant Injury and Ameliorates Renal Ischemia-Reperfusion Injury.

Publications

Endoplasmic Reticulum Stress-Induced Autophagy Provides Cytoprotection from Chemical Hypoxia and Oxidant Injury and Ameliorates Renal Ischemia-Reperfusion Injury.

Similar Datasets

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