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Diabetic nephropathy (DN) has emerged as the foremost cause of end-stage renal disease (ESRD) globally. Endoplasmic reticulum (ER) stress plays a critical role in DN progression. Triterpenoid saponin from Aralia taibaiensis (sAT) has been reported to possess anti-diabetic and anti-oxidant effects. The aim of this study was to examine the influence of sAT on DN treatment and elucidate potential underlying mechanisms. A high-fat diet (HFD) and Streptozotocin (STZ) were employed to induce DN in male Sprague Dawley (SD) rats which were subsequently treated with varying concentrations of sAT for 8 weeks. Our findings reveal that different doses of sAT significantly mitigated hyperglycemia, reduced urinary albumin excretion, and decreased plasma creatinine and blood urea nitrogen levels in DN rats. Moreover, sAT administration improved body weight, alleviated renal fibrosis and histopathological changes in the diabetic kidneys. Notably, sAT treatment partially restored increased Bax expression and decreased Bcl-2 expression. Additionally, sAT inhibited ER stress-related proteins, including GRP78, p-PERK, ATF4 and CHOP in kidneys of DN rats. These results suggest that sAT ameliorated experimental diabetic nephropathy, at least in part, through ER stress pathway. These findings provide a scientific basis for the potential development of sAT as a therapeutic agent for DN treatment.

Spinocerebellar ataxia 19/22 (SCA19/22) is a rare neurodegenerative disorder caused by mutations of the KCND3 gene, which encodes the Kv4. 3 protein. Currently, only 22 KCND3 single-nucleotide mutation sites of SCA19/22 have been reported worldwide, and detailed pathogenesis remains unclear. In this study, Sanger sequencing was used to screen 115 probands of cerebellar ataxia families in 67 patients with sporadic cerebellar ataxia and 200 healthy people to identify KCND3 mutations. Mutant gene products showed pathogenicity damage, and the polarity was changed. Next, we established induced pluripotent stem cells (iPSCs) derived from SCA19/22 patients. Using a transcriptome sequencing technique, we found that protein processing in the endoplasmic reticulum was significantly enriched in SCA19/22-iPS-derived neurons and was closely related to endoplasmic reticulum stress (ERS) and apoptosis. In addition, Western blotting of the SCA19/22-iPS-derived neurons showed a reduction in Kv4.3; but, activation of transcription factor 4 (ATF4) and C/EBP homologous protein was increased. Therefore, the c.1130 C>T (p.T377M) mutation of the KCND3 gene may mediate misfold and aggregation of Kv4.3, which activates the ERS and further induces neuron apoptosis involved in SCA19/22. [ABSTRACT FROM AUTHOR]

Mercuric chloride (HgCl2) is a serious environmental toxicant. So far, the toxicity mechanism of HgCl2 in chicken embryonic kidney (CEK) cells is not still fully understood. In this study, the possible molecular mechanisms of HgCl2 on apoptosis of CEK cells were investigated. Results showed that the cell morphology changed, and cell viability was significantly decreased (P

Diabetic nephropathy (DN) has emerged as the foremost cause of end-stage renal disease (ESRD) globally. Endoplasmic reticulum (ER) stress plays a critical role in DN progression. Triterpenoid saponin from Aralia taibaiensis (sAT) has been reported to possess anti-diabetic and anti-oxidant effects. The aim of this study was to examine the influence of sAT on DN treatment and elucidate potential underlying mechanisms. A high-fat diet (HFD) and Streptozotocin (STZ) were employed to induce DN in male Sprague Dawley (SD) rats which were subsequently treated with varying concentrations of sAT for 8 weeks. Our findings reveal that different doses of sAT significantly mitigated hyperglycemia, reduced urinary albumin excretion, and decreased plasma creatinine and blood urea nitrogen levels in DN rats. Moreover, sAT administration improved body weight, alleviated renal fibrosis and histopathological changes in the diabetic kidneys. Notably, sAT treatment partially restored increased Bax expression and decreased Bcl-2 expression. Additionally, sAT inhibited ER stress-related proteins, including GRP78, p-PERK, ATF4 and CHOP in kidneys of DN rats. These results suggest that sAT ameliorated experimental diabetic nephropathy, at least in part, through ER stress pathway. These findings provide a scientific basis for the potential development of sAT as a therapeutic agent for DN treatment., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jia Cui reports financial support was provided by The National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

ObjectiveAs a high-level nerve center that regulates visceral and endocrine activity, the hypothalamus plays an important role in regulating the body’s stress response. Previous studies have shown that stress can cause damage to hypothalamic neurons. The present study aimed to further clarify the mechanism of endoplasmic reticulum stress (ERS) involvement in hypothalamic neuronal injury.MethodsA 7-day stressed rat model was established with daily restraining for 8 h and forced ice-water swimming for 5 min. The rats were randomly divided into control, stress, stress + GSK2606414 (PERK phosphorylation inhibitor), stress + KIRA6 (IRE1 phosphokinase activity inhibitor), GSK2606414, and KIRA6 groups. The pathological changes of hypothalamic neurons were observed by thionine staining. Expression of ERS proteins GRP78, ATF4, ASK1, JNK, and CHOP in the hypothalamic neurons were observed by immunohistochemical staining. The expression of JNK and CHOP mRNA in the hypothalamic neurons were observed by RNA in situ hybridization (RNA Scope) and the expression of related proteins and mRNA was semiquantitatively analyzed by microscopy-based multicolor tissue cytometry (MMTC).ResultsThionine staining revealed that stress exposure resulted in edema, a lack of Nissl bodies, and pyknosis in hypothalamic neurons. Immunohistochemistry and RNA Scope showed that stress exposure significantly increased the expression of GRP78, ATF4, ASK1, CHOP, JNK, JNK mRNA, and CHOP mRNA. Treatment with PERK and IRE1 inhibitors attenuated pathological damage and downregulated the expression of ATF4, ASK1, JNK, CHOP, JNK mRNA, and CHOP mRNA.ConclusionStress caused pathological changes in rat hypothalamic neurons. ERS PERK-ATF4-CHOP and IRE1-ASK1-JNK pathways were involved in the injury process.

According to the theory of traditional Chinese medicine, the pathogenesis of idiopathic pulmonary fibrosis (IPF) can be attributed to qi deficiency and blood stasis. Buyang Huanwu decoction (BHD), a representative Chinese herbal prescription for qi deficiency and blood stasis syndrome, is widely used to treat IPF in clinical practice. However, its potential mechanisms against IPF remain unclear. This study was carried out to explore the therapeutic effects and underlying mechanisms of BHD on bleomycin (BLM)-induced pulmonary fibrosis in rats. UPLC-MS/MS method was performed to identify the quality of BHD used in this study. Concurrently, a IPF rat model was established by single intratracheal injection of BLM. Pulmonary function test, H&E staining, Masson staining, hydroxyproline assay were conducted to evaluate the therapeutic effects of BHD on BLM-induced pulmonary fibrosis in rats, and the regulatory effect of BHD on endoplasmic reticulum stress (ERS)-mediated alveolar type II epithelial cells (AEC2s) apoptosis in rats was further investigated by TUNEL staining, Western blot, real-time fluorescence quantitative PCR and immunofluorescence co-staining to reveal the potential mechanisms of BHD against IPF. The UPLC-MS/MS analysis showed that the BHD we used complied with the relevant quality control standards. The data from animal experiments confirmed that BHD administration ameliorated BLM-induced pulmonary function decline, lung fibrotic pathological changes and collagen deposition in rats. Further mechanism study revealed that BHD increased the Bcl-2 protein expression, decreased the Bax protein expression and inhibited the cleavage of CASP3 via suppressing the activation of PERK-ATF4-CHOP pathway under continuous ERS, thereby alleviating BLM-induced AEC2s apoptosis of rats. This study demonstrated that BHD ameliorated BLM-induced pulmonary fibrosis in rats by suppressing ERS-mediated AEC2s apoptosis. Our findings can provide some fundamental research basis for the clinical application of BHD in the treatment of IPF. [Display omitted] [ABSTRACT FROM AUTHOR]

The hypothalamus, which is the initial part of the hypothalamic-pituitary-adrenal (HPA) axis, plays a critical role in regulating stress in the central nervous system. The present study aimed to determine whether endoplasmic reticulum stress in hypothalamic neurons is differentially stimulated by varying durations of stress exposure, which ultimately leads to pathological changes in neurons by affecting HPA axis function. There is a need for better morphological evidence of the mechanisms involved in stress-induced neuron injury. A stress model was established in rats by restraining for 8 h and forced ice-water swimming for 5 min each day. The stress-inducing process lasted for 1, 3, 7, 14, and 21 days. Enzyme-linked immunosorbent assay (ELISA) was used to assay serum glucocorticoid levels. Thionine staining was used to observe morphological changes in hypothalamic neurons. Immunohistochemistry and microscopy-based multicolor tissue cytometry (MMTC) was used to detect changes in expression of endoplasmic reticulum stress protein GRP78, ATF4, and CHOP. Serum glucocorticoid levels significantly increased after 3 days of stress exposure and the levels peaked by 7 days. By 21 days, however, the levels were significantly decreased. Thionine staining revealed that prolonged stress exposure resulted in hypothalamic neurons with edema, a lack of Nissl bodies, and pyknotic neurons. Immunohistochemistry and MMTC showed that increasing stress periods significantly decreased GRP78 expression, although ATF4 and CHOP protein expression significantly increased. Stress resulted in pathological changes and significant dynamic changes because of endoplasmic reticulum stress in rat hypothalamic neurons. These results suggested that the endoplasmic reticulum stress PERK-ATF4-CHOP pathway may be associated with hypothalamic neuronal injury.

Background: Endoplasmic reticulum (ER) stress-induced podocyte apoptosis plays a critical role in the development of diabetic nephropathy (DN). Here, we tested the hypothesis that suppression of PERK-ATF4-CHOP pathway by Astragaloside IV (AS-IV) is associated with inhibition of ER stress-induced podocyte apoptosis in streptozotocin (STZ)-induced diabetic rats. Methods: Diabetic rats were treated with AS-IV at 5 and 10 mg· kg-1· d-1, p.o., for 12 weeks. Albuminuria examination, hematoxylin & eosin staining and TUNEL analysis were performed. Immunohistochemistry, western blot, and real-time PCR were used to detect renal expression of ER chaperone GRP78 and ER-associated apoptosis proteins. Results: Treatment with AS-IV ameliorated albuminuria and renal histopathology in diabetic rats. Diabetic rats had significant increment in podocyte apoptosis as well as phosphorylated PERK and eIF2α in the kidneys, which were attenuated by AS-IV treatment. Furthermore, diabetic rats were found to have increased protein and mRNA expressions of GRP78 and ER-associated apoptosis proteins, such as ATF4, CHOP and TRB3, which were also attenuated by AS-IV treatment. Increased Bax expression and decreased Bcl-2 expression were detected in diabetic rats, and these changes were partially restored by AS-IV treatment. Conclusion: The protective effect of AS-IV on ER stress-induced podocyte apoptosis is associated with inhibition of PERK-ATF4-CHOP pathway. Down-regulation of PERK- ATF4-CHOP pathway by AS-IV may be a novel strategy for the treatment of DN.

Endoplasmic reticulum (ER) stress-induced cell injury plays an important role in the development of drug-induced liver injury (DILI). However, little is known about the contribution of ER stress to RFP-induced cell injury. In our study, L02 cells were treated with different concentrations of RFP for different time intervals, and cell apoptosis, the survival rate, and the gene and protein expression of GRP78, PERK, ATF4, and CHOP were measured. Additionally, L02 cells were transfected with CHOP-siRNA or a CHOP-over expression plasmid or administered 4-PBA before treatment with RFP. We found that RFP increased the cell apoptosis rate, decreased cell survival, and increased the protein and gene levels of GRP78, PERK, ATF4 and CHOP in both a dose-dependent and a time-dependent manner. Following the transient knockdown of CHOP and treatment with RFP, cell apoptosis decreased and the survival rate increased. Overexpression of CHOP produced the opposite effects. Treatment with 4-PBA decreased the protein and gene expression of GRP78, PERK, ATF4 and CHOP. Additionally, 4-PBA reduced cell apoptosis, increased cell survival and decreased the level of ALT, AST, AKP, LDH and ATP in the cell culture supernatant. These results indicate that 4-PBA alleviates RFP-induced injury in L02 cells via inhibition of the PERK-ATF4-CHOP pathway. [ABSTRACT FROM AUTHOR]

Background: Endoplasmic reticulum (ER) stress-induced podocyte apoptosis plays a critical role in the development of diabetic nephropathy (DN). Here, we tested the hypothesis that suppression of PERK-ATF4-CHOP pathway by Astragaloside IV (AS-IV) is associated with inhibition of ER stress-induced podocyte apoptosis in streptozotocin (STZ)-induced diabetic rats. Methods: Diabetic rats were treated with AS-IV at 5 and 10 mg· kg-1· d-1, p.o., for 12 weeks. Albuminuria examination, hematoxylin & eosin staining and TUNEL analysis were performed. Immunohistochemistry, western blot, and real-time PCR were used to detect renal expression of ER chaperone GRP78 and ER-associated apoptosis proteins. Results: Treatment with AS-IV ameliorated albuminuria and renal histopathology in diabetic rats. Diabetic rats had significant increment in podocyte apoptosis as well as phosphorylated PERK and eIF2α in the kidneys, which were attenuated by AS-IV treatment. Furthermore, diabetic rats were found to have increased protein and mRNA expressions of GRP78 and ER-associated apoptosis proteins, such as ATF4, CHOP and TRB3, which were also attenuated by AS-IV treatment. Increased Bax expression and decreased Bcl-2 expression were detected in diabetic rats, and these changes were partially restored by AS-IV treatment. Conclusion: The protective effect of AS-IV on ER stress-induced podocyte apoptosis is associated with inhibition of PERK-ATF4-CHOP pathway. Down-regulation of PERK- ATF4-CHOP pathway by AS-IV may be a novel strategy for the treatment of DN. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) has a high recurrence rate and mortality rate even after surgery. Low-density lipoprotein receptor-related protein 1B (LRP1B) has proven to be involved in tumor development and progression of multiple malignancies. However, the function of LRP1B in HCC progression has not been fully elucidated. Thus, we conducted this study to explore the relationship between LRP1B and HCC. Bioinformatic analyses implied that LRP1B was highly expressed in HCC tissues. High LRP1B expression was shown to be related to poor outcomes and the determination of HCC patients' tumor stage. LRP1B deletion impeded the proliferation, migration, and invasion of HCC cells. Further investigation demonstrated that silencing LRP1B expression enhanced the sensitivity of HCC cells to doxorubicin. LRP1B deletion inhibited HCC progression by regulating the PERK-ATF4-CHOP signaling pathway. Additionally, we probed the genomic alterations of LRP1B in HCC and the impact on the prognosis of patients. Collectively, our results suggest that LRP1B plays an essential role in the promotion of HCC progression by regulating the PERK-ATF4-CHOP signaling pathway, which is a potential prognostic biomarker and a promising therapeutic target of HCC.

Mercuric chloride (HgCl 2 ) is a serious environmental toxicant. So far, the toxicity mechanism of HgCl 2 in chicken embryonic kidney (CEK) cells is not still fully understood. In this study, the possible molecular mechanisms of HgCl 2 on apoptosis of CEK cells were investigated. Results showed that the cell morphology changed, and cell viability was significantly decreased (P < 0.05) after HgCl 2 exposure. Besides, apoptosis rate was significantly increased after HgCl 2 exposure (P < 0.05). The gene and protein expressions of B-cell lymphoma-2 associate X/B-cell lymphoma-2 (P < 0.05), caspase-3 (P < 0.05), and caspase-9 (P < 0.05) were significantly enhanced by HgCl 2 in CEK cells. We also found that intracellular reactive oxygen species level was significantly enhanced (P < 0.05), and the flux of calcium ion to mitochondria occurred after HgCl 2 exposure. In terms of molecular mechanisms, the mRNA and protein expressions associated with endoplasmic reticulum (ER) stress were significantly increased after HgCl 2 exposure (P < 0.05), including glucose regulated protein 78, protein kinase RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP). However, pretreated with 1-μmol/L 4-phenylbutyrate (ER stress inhibitor) alleviated the apoptosis and downregulated PERK-ATF4-CHOP pathway in CEK cells. Taken together, upregulation of PERK-ATF4-CHOP pathway of ER stress induced by HgCl 2 is associated with apoptosis in CEK cells., (Copyright © 2020. Published by Elsevier Inc.)

Objective: As a high-level nerve center that regulates visceral and endocrine activity, the hypothalamus plays an important role in regulating the body's stress response. Previous studies have shown that stress can cause damage to hypothalamic neurons. The present study aimed to further clarify the mechanism of endoplasmic reticulum stress (ERS) involvement in hypothalamic neuronal injury., Methods: A 7-day stressed rat model was established with daily restraining for 8 h and forced ice-water swimming for 5 min. The rats were randomly divided into control, stress, stress + GSK2606414 (PERK phosphorylation inhibitor), stress + KIRA6 (IRE1 phosphokinase activity inhibitor), GSK2606414, and KIRA6 groups. The pathological changes of hypothalamic neurons were observed by thionine staining. Expression of ERS proteins GRP78, ATF4, ASK1, JNK, and CHOP in the hypothalamic neurons were observed by immunohistochemical staining. The expression of JNK and CHOP mRNA in the hypothalamic neurons were observed by RNA in situ hybridization (RNA Scope) and the expression of related proteins and mRNA was semiquantitatively analyzed by microscopy-based multicolor tissue cytometry (MMTC)., Results: Thionine staining revealed that stress exposure resulted in edema, a lack of Nissl bodies, and pyknosis in hypothalamic neurons. Immunohistochemistry and RNA Scope showed that stress exposure significantly increased the expression of GRP78, ATF4, ASK1, CHOP, JNK, JNK mRNA, and CHOP mRNA. Treatment with PERK and IRE1 inhibitors attenuated pathological damage and downregulated the expression of ATF4, ASK1, JNK, CHOP, JNK mRNA, and CHOP mRNA., Conclusion: Stress caused pathological changes in rat hypothalamic neurons. ERS PERK-ATF4-CHOP and IRE1-ASK1-JNK pathways were involved in the injury process.

The hypothalamus, which is the initial part of the hypothalamic-pituitary-adrenal (HPA) axis, plays a critical role in regulating stress in the central nervous system. The present study aimed to determine whether endoplasmic reticulum stress in hypothalamic neurons is differentially stimulated by varying durations of stress exposure, which ultimately leads to pathological changes in neurons by affecting HPA axis function. There is a need for better morphological evidence of the mechanisms involved in stress-induced neuron injury. A stress model was established in rats by restraining for 8 h and forced ice-water swimming for 5 min each day. The stress-inducing process lasted for 1, 3, 7, 14, and 21 days. Enzyme-linked immunosorbent assay (ELISA) was used to assay serum glucocorticoid levels. Thionine staining was used to observe morphological changes in hypothalamic neurons. Immunohistochemistry and microscopy-based multicolor tissue cytometry (MMTC) was used to detect changes in expression of endoplasmic reticulum stress protein GRP78, ATF4, and CHOP. Serum glucocorticoid levels significantly increased after 3 days of stress exposure and the levels peaked by 7 days. By 21 days, however, the levels were significantly decreased. Thionine staining revealed that prolonged stress exposure resulted in hypothalamic neurons with edema, a lack of Nissl bodies, and pyknotic neurons. Immunohistochemistry and MMTC showed that increasing stress periods significantly decreased GRP78 expression, although ATF4 and CHOP protein expression significantly increased. Stress resulted in pathological changes and significant dynamic changes because of endoplasmic reticulum stress in rat hypothalamic neurons. These results suggested that the endoplasmic reticulum stress PERK-ATF4-CHOP pathway may be associated with hypothalamic neuronal injury.