Mesenchymal stem cells reduce ER stress via PERK-Nrf2 pathway in an aged mouse model

Mechanisms of Bleomycin-induced Lung Fibrosis: A Review of Therapeutic Targets and Approaches

Pulmonary toxicity is a serious side effect of some specific anticancer drugs. Bleomycin is a well-known anticancer drug that triggers severe reactions in the lungs. It is an approved drug that may be prescribed for the treatment of testicular cancers, Hodgkin's and non-Hodgkin's lymphomas, ovarian cancer, head and neck cancers, and cervical cancer. A large number of experimental studies and clinical findings show that bleomycin can concentrate in lung tissue, leading to massive oxidative stress, alveolar epithelial cell death, the proliferation of fibroblasts, and finally the infiltration of immune cells. Chronic release of pro-inflammatory and pro-fibrotic molecules by immune cells and fibroblasts leads to pneumonitis and fibrosis. Both fibrosis and pneumonitis are serious concerns for patients who receive bleomycin and may lead to death. Therefore, the management of lung toxicity following cancer therapy with bleomycin is a critical issue. This review explains the cellular and molecular mechanisms of pulmonary injury following treatment with bleomycin. Furthermore, we review therapeutic targets and possible promising strategies for ameliorating bleomycin-induced lung injury.

Effects of folic acid on oxidative damage of kidney in lead-exposed rats

INTRODUCTION

Lead (Pb) has many applications in daily life, but in recent years, various problems caused by lead exposure have aroused people's concern. Folic acid is widely found in fruits and has received more attention for its antioxidant function. However, the role of folic acid in lead-induced kidney injury in rats is unclear. This study was designed to investigate the effects of folic acid on oxidative stress and endoplasmic reticulum stress in the kidney of rats caused by lead exposure.

METHODS

Forty specific pathogen-free male Rattus norvegicus rats were randomly divided into control, lead, intervention, and folic acid groups. The levels of SOD, GSH-Px, GSH, and MDA were measured by biochemical kits. The protein levels of Nrf2, HO-1, CHOP, and GRP78 were measured by immunofluorescence.

RESULTS

This study showed that lead exposure increased the blood levels of lead in mice. However, the intervention of folic acid decreased the levels of lead, but the difference was not statistically significant. Lead exposure causes oxidative stress by decreasing kidney SOD, GSH-Px, and GSH levels and increasing MDA levels. However, folic acid alleviated the oxidative damage caused by lead exposure by increasing the levels of GSH-Px and GSH and decreasing the levels of MDA. Immunofluorescence results showed that folic acid intervention downregulated the upregulation of kidney Nrf2, HO-1, GRP78, and CHOP expression caused by lead exposure.

DISCUSSION

Overall, folic acid alleviates kidney oxidative stress induced by lead exposure by regulating Nrf2 and HO-1, while regulating CHOP and GRP78 to mitigate apoptosis caused by excessive endoplasmic reticulum stress.

Maternal hypothyroidism causes oxidative stress and endoplasmic reticulum stress in the maternal-fetal interface of rats

Maternal hypothyroidism is associated with pre-eclampsia and intrauterine growth restriction, gestational diseases involving oxidative stress (OS) and endoplasmic reticulum stress (ERS) in the placenta. However, it is not known whether hypothyroidism also causes OS and ERS at the maternal-fetal interface. The aim was to evaluate the fetal-placental development and the expression of mediators of OS and of the unfolded protein response (UPR) in the maternal-fetal interface of hypothyroid rats. Hypothyroidism was induced in Wistar rats with propylthiouracil and the fetal-placental development and placental and decidual expression of antioxidant, hypoxia, and UPR mediators were analyzed at 14 and 18 days of gestation (DG), as well the expression of 8-OHdG and MDA, and reactive oxygen species (ROS) and peroxynitrite levels. Hypothyroidism reduced fetal weight at 14 and 18 DG, in addition to increasing the percentage of fetal death and reducing the weight of the uteroplacental unit at 18 DG. At 14 DG, there was greater decidual and/or placental immunostaining of Hif1α, 8-OHdG, MDA, SOD1, GPx1/2, Grp78 and CHOP in hypothyroid rats, while there was a reduction in placental and/or decidual gene expression of Sod1, Gpx1, Atf6, Perk, Ho1, Xbp1, Grp78 and Chop in the same gestational period. At 18 DG, hypothyroidism increased the placental ROS levels and the decidual and/or placental immunostaining of HIF1α, 8-OHdG, MDA, ATF4, GRP78 and CHOP, while it reduced the immunostaining and enzymatic activity of SOD1, CAT, GST. Hypothyroidism increased the placental mRNA expression of Hifα, Nrf2, Sod2, Gpx1, Cat, Perk, Atf6 and Chop at 18 DG, while decreasing the decidual expression of Sod2, Cat and Atf6. These findings demonstrated that fetal-placental restriction in female rats with hypothyroidism is associated with hypoxia and dysregulation in placental and decidual expression of UPR mediators and antioxidant enzymes, and activation of oxidative stress and endoplasmic reticulum stress at the maternal-fetal interface.

Gossypol Induces Apoptosis of Human Pancreatic Cancer Cells via CHOP/Endoplasmic Reticulum Stress Signaling Pathway

Gossypol, a natural phenolic aldehyde present in cotton plants, was originally used as a means of contraception, but is currently being studied for its anti-proliferative and anti-metastatic effects on various cancers. However, the intracellular mechanism of action regarding the effects of gossypol on pancreatic cancer cells remains unclear. Here, we investigated the anti-cancer effects of gossypol on human pancreatic cancer cells (BxPC-3 and MIA PaCa-2). Cell counting kit-8 assays, annexin V/propidium iodide staining assays, and transmission electron microscopy showed that gossypol induced apoptotic cell death and apoptotic body formation in both cell lines. RNA sequencing analysis also showed that gossypol increased the mRNA levels of CCAAT/enhancer-binding protein homologous protein (CHOP) and activating transcription factor 3 (ATF3) in pancreatic cancer cell lines. In addition, gossypol facilitated the cleavage of caspase-3 via protein kinase RNA-like ER kinase (PERK), CHOP, and Bax/Bcl-2 upregulation in both cells, whereas the upregulation of ATF was limited to BxPC-3 cells. Finally, a three-dimensional culture experiment confirmed the successful suppression of cancer cell spheroids via gossypol treatment. Taken together, our data suggest that gossypol may trigger apoptosis in pancreatic cancer cells via the PERK-CHOP signaling pathway. These findings propose a promising therapeutic approach to pancreatic cancer treatment using gossypol.

Ferroptosis and Ferritinophagy in Diabetes Complications

With long-term metabolic malfunction, diabetes can cause more serious damage to the whole body tissue and organs, resulting in a variety of complications. Therefore, it is particularly important to further explore the pathogenesis of diabetes complications and develop drugs for prevention and treatment. In recent years, ferroptosis has been recognized as a new regulatory mode of cell death different from apoptosis and necrosis, which involves the regulation of nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy. Evidence shows that ferroptosis and ferritinophagy provide a significant role in the occurrence and development of diabetes complications. This article systematically reviews the current understanding of ferroptosis and ferritinophagy, focusing on their potential mechanisms, connection, and regulation. We discuss their involvement in diabetes complications and consider emerging therapeutic opportunities and the associated challenges with future prospects.

Mesenchymal stromal cells attenuate alveolar type 2 cells senescence through regulating NAMPT-mediated NAD metabolism

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive deadly fibrotic lung disease with high prevalence and mortality worldwide. The therapeutic potential of mesenchymal stem cells (MSCs) in pulmonary fibrosis may be attributed to the strong paracrine, anti-inflammatory, anti-apoptosis and immunoregulatory effects. However, the mechanisms underlying the therapeutic effects of MSCs in IPF, especially in terms of alveolar type 2 (AT2) cells senescence, are not well understood. The purpose of this study was to evaluate the role of MSCs in NAD metabolism and senescence of AT2 cells in vitro and in vivo.

Methods

MSCs were isolated from human bone marrow. The protective effects of MSCs injection in pulmonary fibrosis were assessed via bleomycin mouse models. The senescence of AT2 cells co-cultured with MSCs was evaluated by SA-β-galactosidase assay, immunofluorescence staining and Western blotting. NAD+ level and NAMPT expression in AT2 cells affected by MSCs were determined in vitro and in vivo. FK866 and NAMPT shRNA vectors were used to determine the role of NAMPT in MSCs inhibiting AT2 cells senescence.

Results

We proved that MSCs attenuate bleomycin-induced pulmonary fibrosis in mice. Senescence of AT2 cells was alleviated in MSCs-treated pulmonary fibrosis mice and when co-cultured with MSCs in vitro. Mechanistic studies showed that NAD+ and NAMPT levels were rescued in AT2 cells co-cultured with MSCs and MSCs could suppress AT2 cells senescence mainly via suppressing lysosome-mediated NAMPT degradation.

Conclusions

MSCs attenuate AT2 cells senescence by upregulating NAMPT expression and NAD+ levels, thus exerting protective effects in pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02688-w.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.

Activation of the EGFR-PI3K-CaM pathway by PRL-1-overexpressing placenta-derived mesenchymal stem cells ameliorates liver cirrhosis via ER stress-dependent calcium

Background

Cholesterol accumulation and calcium depletion induce hepatic injury via the endoplasmic reticulum (ER) stress response. ER stress regulates the calcium imbalance between the ER and mitochondria. We previously reported that phosphatase of regenerating liver-1 (PRL-1)-overexpressing placenta-derived mesenchymal stem cells (PD-MSCs^PRL−1) promoted liver regeneration via mitochondrial dynamics in a cirrhotic rat model. However, the role of PRL-1 in ER stress-dependent calcium is not clear. Therefore, we demonstrated that PD-MSCs^PRL−1 improved hepatic functions by regulating ER stress and calcium channels in a rat model of bile duct ligation (BDL).

Methods

Liver cirrhosis was induced in Sprague–Dawley (SD) rats using surgically induced BDL for 10 days. PD-MSCs and PD-MSCs^PRL−1 (2 × 10⁶ cells) were intravenously administered to animals, and their therapeutic effects were analyzed. WB-F344 cells exposed to thapsigargin (TG) were cocultured with PD-MSCs or PD-MSCs^PRL−1.

Results

ER stress markers, e.g., eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP), were increased in the nontransplantation group (NTx) compared to the control group. PD-MSCs^PRL−1 significantly decreased ER stress markers compared to NTx and induced dynamic changes in calcium channel markers, e.g., sarco/endoplasmic reticulum Ca²⁺ -ATPase 2b (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3R), mitochondrial calcium uniporter (MCU), and voltage-dependent anion channel 1 (VDAC1) (*p < 0.05). Cocultivation of TG-treated WB-F344 cells with PD-MSCs^PRL−1 decreased cytosolic calmodulin (CaM) expression and cytosolic and mitochondrial Ca²⁺ concentrations. However, the ER Ca²⁺ concentration was increased compared to PD-MSCs (*p  < 0.05). PRL-1 activated phosphatidylinositol-3-kinase (PI3K) signaling via epidermal growth factor receptor (EGFR), which resulted in calcium increase via CaM expression.

Conclusions

These findings suggest that PD-MSCs^PRL−1 improved hepatic functions via calcium changes and attenuated ER stress in a BDL-injured rat model. Therefore, these results provide useful data for the development of next-generation MSC-based stem cell therapy for regenerative medicine in chronic liver disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02616-y.

Endovascular Stem Cell Therapy Post Stroke Rescues Neurons from Endoplasmic Reticulum Stress-Induced Apoptosis by Modulating Brain-Derived Neurotrophic Factor/Tropomyosin Receptor Kinase B Signaling

Ischemic stroke is devastating, with serious long-term disabilities affecting millions of people worldwide. Growing evidence has shown that mesenchymal stem cells (MSCs) administration after stroke provides neuroprotection and enhances the quality of life in stroke patients. Previous studies from our lab have shown that 1 × 10⁵ MSCs administered intra-arterially (IA) at 6 h post stroke provide neuroprotection through the modulation of inflammasome and calcineurin signaling. Ischemic stroke induces endoplasmic reticulum (ER) stress, which exacerbates the pathology. The current study intends to understand the involvement of brain-derived neurotrophic factor/tropomyosin receptor kinase B (BDNF/TrkB) signaling in preventing apoptosis induced by ER stress post stroke following IA MSCs administration. Ischemic stroke was induced in ovariectomized female Sprague Dawley rats. The MSCs were administered IA, and animals were sacrificed at 24 h post stroke. Infarct area, neurological deficit score, motor coordination, and biochemical parameters were evaluated. The expression of various genes and proteins was assessed. An inhibition study was also carried out to confirm the involvement of BDNF/TrkB signaling in ER stress-induced apoptosis. IA-administered MSCs improved functional outcomes, reduced infarct area, increased neuronal survival, and normalized biochemical parameters. mRNA and protein expression of ER stress markers were reduced, while those of BDNF and TrkB were increased. Reduction in ER stress-mediated apoptosis was also observed. The present study shows that IA MSCs administration post stroke provides neuroprotection and can modulate ER stress-mediated apoptosis via the BDNF/TrkB signaling pathway.

The Impact of Endoplasmic Reticulum-Associated Protein Modifications, Folding and Degradation on Lung Structure and Function

The accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and induces the unfolded protein response (UPR) and other mechanisms to restore ER homeostasis, including translational shutdown, increased targeting of mRNAs for degradation by the IRE1-dependent decay pathway, selective translation of proteins that contribute to the protein folding capacity of the ER, and activation of the ER-associated degradation machinery. When ER stress is excessive or prolonged and these mechanisms fail to restore proteostasis, the UPR triggers the cell to undergo apoptosis. This review also examines the overlooked role of post-translational modifications and their roles in protein processing and effects on ER stress and the UPR. Finally, these effects are examined in the context of lung structure, function, and disease.

Therapeutic mechanisms of mesenchymal stem cells in acute respiratory distress syndrome reveal potentials for Covid-19 treatment

The mortality rate of critically ill patients with acute respiratory distress syndrome (ARDS) is 30.9% to 46.1%. The emergence of the coronavirus disease 2019 (Covid-19) has become a global issue with raising dire concerns. Patients with severe Covid-19 may progress toward ARDS. Mesenchymal stem cells (MSCs) can be derived from bone marrow, umbilical cord, adipose tissue and so on. The easy accessibility and low immunogenicity enable MSCs for allogeneic administration, and thus they were widely used in animal and clinical studies. Accumulating evidence suggests that mesenchymal stem cell infusion can ameliorate ARDS. However, the underlying mechanisms of MSCs need to be discussed. Recent studies showed MSCs can modulate immune/inflammatory cells, attenuate endoplasmic reticulum stress, and inhibit pulmonary fibrosis. The paracrine cytokines and exosomes may account for these beneficial effects. In this review, we summarize the therapeutic mechanisms of MSCs in ARDS, analyzed the most recent animal experiments and Covid-19 clinical trial results, discussed the adverse effects and prospects in the recent studies, and highlight the potential roles of MSC therapy for Covid-19 patients with ARDS.

Contemporary Concise Review 2020: Interstitial lung disease

The year 2020 was one like no other, as we witnessed the far-reaching impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) global pandemic. Yet despite an unprecedented and challenging year, global research in interstitial lung disease (ILD) continued to break new grounds. Research progress has led to an improved understanding in new diagnostic tools and potential biomarkers for ILD. Studies on the role of antifibrotic therapies, newer therapeutic agents, supportive care strategies and the impact of coronavirus disease 2019 (COVID-19) continue to reshape the management landscape of ILD. In this concise review, we aim to summarize the key studies published in 2020, highlighting their impact on the various aspects of ILD.

Diagnosis and treatment of drug-induced interstitial lung disease

Drug-induced interstitial lung disease (DILD) is a group of adverse drug reactions that is rare but fatally toxic. Pulmonary toxicity causes inflammation and subsequent interstitial fibrosis. As novel drugs with a variety of purposes are introduced into the medical field, the number of culprit medications that are suspected to cause lung complications is accordingly increasing. In this review, DILD will be discussed from several aspects such as causality by numerous drugs, check points for a timely diagnosis, alongside some contemporary treatment options. The exact mechanism of DILD has not been elucidated, and a useful clinical, radiological, or pathological confirmation process is still lacking. Common drugs which casue DILD include bleomycin, amiodarone, epidermal growth factor receptor-targeted agents, and immune checkpoint inhibitors. Diagnosis is based on a suspicious drug administration history, somewhat inconsistent clinical symptoms and signs, radiological hints, and histopathological assistance, together with the exclusion of other lung-injuring etiologies. Cessation of the suspected drug, meticulous corticosteroid usage, and ancillary supportive management are the mainstay therapeutic strategy for DILD. Most cases of DILD respond to these countermeasures and reductions, but in some cases the fibrotic process worsens, leading to irreversible sequelae on the affected lung.

Immortalized canine adipose-derived mesenchymal stem cells alleviate gentamicin-induced acute kidney injury by inhibiting endoplasmic reticulum stress in mice and dogs

Adipose-derived mesenchymal stem cells have been used to treat acute kidney injury (AKI). The role of endoplasmic reticulum (ER) stress in AKI treatment with canine adipose-derived mesenchymal stem cells (cADSCs) remains unknown. This study intended to investigate the therapeutic effects of cADSCs cultured in different media on AKI in mice and dogs and reveal the role of ER stress in this process. The mice were divided into two branches: a control group and a gentamicin induced group (this group treated with low-serum ADSC or high-serum ADSC or 4-phenylbutyric acid (4-PBA)). The dogs were divided into control, model, and cell-injected groups. To suppress ER stress, mice were simultaneously treated with 4-PBA. The results showed there were improvements in renal function and tissue damage and a corresponding decrease in ER stress in the kidneys of the mice that received cell injection. However, the cells cultured with 2% FBS showed a better growth state and resulted in lower ER stress levels in treated kidneys. In the 4-PBA-treated group, ER stress was suppressed, and there was corresponding kidney injury recovery. Similarly, both kidney damage and ER stress were alleviated after AKI dogs were injected with the cells. Our findings reveal that both allogeneic and xenogeneic cADSCs were effective treatments for AKI by inhibiting ER stress. These results also provide evidence for a new clinical therapy for acute renal disease in pets.

Mesenchymal stem cells ameliorate oxidative stress, inflammation, and hepatic fibrosis via Nrf2/HO-1 signaling pathway in rats

Liver fibrosis occurs in most types of chronic liver diseases and can develop into cirrhosis and liver failure. Bone marrow-derived mesenchymal stem cells (BMSCs) showed promising effects in the treatment of fibrosis. This study evaluated the possible role of Nrf2/HO-1 signaling in the ameliorative effect of BMSCs against carbon tetrachloride (CCl₄)-induced liver fibrosis, oxidative stress, and inflammation in rats. Hepatic fibrosis was induced by subcutaneous injection of CCl₄ twice per week for 6 consecutive weeks and rat BMSCs were administered intravenously. After 4 weeks, the rats were sacrificed, and samples were collected for analysis. CCl₄-intoxicated rats showed elevated serum transaminases, ALP, γGT, bilirubin and pro-inflammatory cytokines, and decreased albumin. Hepatic NF-κB p65 and malondialdehyde (MDA) were significantly increased, and cellular antioxidants were decreased in CCl₄-intoxicated rats. BMSCs ameliorated liver function markers, suppressed MDA, NF-κB p65, and inflammatory cytokines, and enhanced antioxidants in the liver of CCl₄-intoxicated rats. BMSCs were engrafted within the liver tissue and prevented histological alterations and collagen accumulation induced by CCl₄. In addition, BMSCs upregulated hepatic Nrf2 and HO-1 expression in CCl₄-intoxicated rats. In conclusion, this study provides evidence that BMSCs suppress oxidative stress, inflammation, and liver fibrosis through a mechanism involving activation of the Nrf2/HO-1 signaling.

How the Pathological Microenvironment Affects the Behavior of Mesenchymal Stem Cells in the Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by fibroblasts activation, ECM accumulation, and diffused alveolar inflammation. The role of inflammation in IPF is still controversial and its involvement may follow nontraditional mechanisms. It is seen that a pathological microenvironment may affect cells, in particular mesenchymal stem cells (MSCs) that may be able to sustain the inflamed microenvironment and influence the surrounding cells. Here MSCs have been isolated from fibrotic (IPF-MSCs) and control (C-MSCs) lung tissue; first cells were characterized and compared by the expression of molecules related to ECM, inflammation, and other interdependent pathways such as hypoxia and oxidative stress. Subsequently, MSCs were co-cultured between them and with NHLF to test the effects of the cellular crosstalk. Results showed that pathological microenvironment modified the features of MSCs: IPF-MSCs, compared to C-MSCs, express higher level of molecules related to ECM, inflammation, oxidative stress, and hypoxia; notably, when co-cultured with C-MSCs and NHLF, IPF-MSCs are able to induce a pathological phenotype on the surrounding cell types. In conclusion, in IPF the pathological microenvironment affects MSCs that in turn can modulate the behavior of other cell types favoring the progression of IPF.

Up-regulation of PERK/Nrf2/HO-1 axis protects myocardial tissues of mice from damage triggered by ischemia-reperfusion through ameliorating endoplasmic reticulum stress

Background

Ischemia-reperfusion (I/R) injury, which leads to additionally cardiac tissue damage, is a severe adverse effect of reperfusion therapeutics used for the treatment of acute myocardial infarction. Agents capable of alleviating I/R-induced myocardial injury are urgently needed. In this study, we investigated whether up-regulation of PERK/Nrf2/HO-1 axis provided protective roles for murine myocardium suffering I/R intervention.

Methods

The in vivo I/R model was formed by ligation of the left anterior descending (LAD) coronary artery of C57BL/6J mice. All animals were assigned into the following groups at random: sham, I/R, rAAV9-PERK + I/R, rAAV9-Nrf2 + I/R, rAAV9-HO-1 + I/R, siRNA-HO-1 + rAAV9-PERK + I/R. The ligation of LAD was released after 30 min of ischemia, which was followed by reperfusion of LAD for 4 h. Then the cardiac tissues and blood serum were collected. TUNEL staining, ELISA assay, TTC staining, Western blotting and real-time PCR were used to determine I/R injury-related indicators.

Results

Our results showed that I/R administration triggered cardiomyocytes apoptosis and LDH and CK-MB release, yet overexpression of PERK decreased cellular apoptosis index in the cardiac tissue and reduced levels of LDH and CK-MB in the serum. We further found that the protective actions of PERK against I/R-evoked cardiac damage might be attributed to up-regulation of Nrf2/HO-1 signaling transduction, given that overexpression of Nrf2 and HO-1 ameliorated cardiac cell apoptosis and reduced the size of infarction and ischemia in the myocardial tissue, yet gene silencing of HO-1 invalidated the beneficial roles of PERK overexpression in improving I/R-induced cardiac injury. Then, we investigated whether PERK-activated Nrf2/HO-1 cascade affected endoplasmic reticulum stress (ERS), considering the crucial roles of ERS-associated apoptosis in the development of I/R damage. Our findings indicated that up-regulation of PERK-mediated Nrf2/HO-1 pathway induced the expression reduction of GRP78, CRT, CHOP and caspase-12 both at the transcriptional and translational level.

Conclusions

We, for the first time, discovered that up-regulation of PERK/Nrf2/HO-1 axis improved I/R-induced myocardial injury via reducing ERS-related signal molecules and downstream pro-apoptotic factors.