Levels Of CHOP Research Articles

HDAC4 regulates apoptosis in Acan-CreERT2;HDAC4d /d mice with osteoarthritis by downregulating ATF4.

Several studies have previously shown that histone deacetylase 4 (HDAC4) can regulate endoplasmic reticulum stress-induced apoptosis through the activating transcription factor 4 (ATF4)/CAAT/enhancer binding protein homologous (CHOP) signaling pathway, thereby affecting the progression of osteoarthritis (OA). The present study investigated the regulatory mechanism of HDAC4 in chondrocyte apoptosis in OA using Acan-CreERT2;HDAC4fl/fl gene knockout mice. Forty mice were divided into four groups: TM-DMM group [tamoxifen (TM) injection at 2 months of age and destabilization of the medial meniscus (DMM) surgery at 3 months], TM-sham group (TM injection at 2 months of age and sham surgery at 3 months), no TM-DMM group (corn oil injection at 2 months of age and DMM surgery at 3 months) and no TM-sham group (corn oil injection at 2 months of age and sham surgery at 3 months). Apoptosis and cartilage damage were assessed through imaging, histological analysis, immunohistochemistry, reverse transcriptase-PCR and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. HDAC4 knockdown resulted in increased osteophyte formation, significant narrowing of the joint space and increased articular cartilage damage. Furthermore, expression levels of key apoptosis-related markers, ATF4, CHOP, caspase-3 and caspase-9, were significantly higher in the TM groups than in their respective control groups. Taken together, our results suggest that HDAC4 deficiency leads to increased apoptosis induced by the ATF4/CHOP signaling pathway in the pathogenesis of OA. Therefore, upregulation of HDAC4 may represent a potential therapeutic strategy.

Thiacloprid Exposure Induces Oxidative Stress, Endoplasmic Reticulum Stress, and Apoptosis in the Liver of Mauremys reevesii.

Among neonicotinoid insecticides, thiacloprid (THI) is extensively utilized in agricultural practices, which poses a potential toxicity risk to aquatic fauna. Turtles, integral to aquatic ecosystems, have not yet been comprehensively assessed for their vulnerability to THI exposure. In this study, we aimed to evaluate the effects of THI on oxidative stress, endoplasmic reticulum stress (ERS), and apoptosis in aquatic turtles. We categorized Mauremys reevesii into three groups: a control group and two experimental groups exposed to environmentally relevant (4.5 μg/mL) and high (15 mg/mL) concentrations of THI, respectively. Transcriptome analysis revealed that genes significantly associated with the elimination of superoxide radicals, organelle inner membrane functions, peroxiredoxin activity, and apoptotic pathways were abundantly expressed in the high-concentration THI group. Notably, exposure to high concentrations of THI led to a marked increase in glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, whereas catalase (CAT) activity declined and malondialdehyde (MDA) levels rose, indicating the presence of oxidative stress. Moreover, THI upregulated the expression of the ER stress marker GRP78. Simultaneously, the mRNA levels of pivotal unfolded protein response genes, including AFT6, AFT4, IRE1α, CHOP, XBP1, and eIF2α, were significantly elevated in response to THI exposure. Furthermore, high concentrations of THI significantly activated the activities of caspase-3, caspase-8, and caspase-9 enzymes in the liver tissue. The expression of anti-apoptotic gene Bcl-2 was downregulated, whereas the pro-apoptotic genes Bax and caspase-3 were upregulated, leading to an increase in hepatic apoptotic cells following THI exposure. Collectively, our study indicates that THI can induce hepatic damage in turtles through the promotion of oxidative stress, ERS, and apoptosis. These findings gain a deeper understanding of the toxic effects of THI on keystone species in aquatic ecosystems, thereby improving our overall understanding of their environmental impacts.

The mechanism of endoplasmic reticulum (ER) stress in cell apoptosis and ROS (reactive oxygen species) of CNE2 cell line induced by single wall carbon nanohorn (SWCNH)

IntroductionThe interaction between the materials themselves and cancer cells are rarely explored. Therefore, the biological roles of raw single wall carbon nanohorn (SWCNH) on endoplasmic reticulum (ER) stress in the apoptosis of CNE2 were explored.MethodsTherefore, ERS of CNE2 cells was induced by SWCNH, and 4-phenylbutyrate (4-PBA) was selected as a inhibitor of ERS. CNE2 cells were co-cultured with SWCNH, 4-PBA and SWCNH+4-PBA, respectively. Furthermore, the apoptotic status of CNE2 cells and its ROS (Reactive oxygen species) levels were determined. Moreover, the apoptotic protein expression of caspase 3 (cysteinyl aspartate specific proteinase 3), the expression levels of ER pathway protein eIF2α, ATF4 and CHOP, or the OS (Oxidative stress)-related proteins NQO1, GCLC, HO-1, and Nrf2 was detected, respectively.ResultsCNE2 apoptotic rate, ROS levels, the caspase 3 or ER pathway proteins ATF4 and CHOP expression, even the NQO1, GCLC, HO-1, and Nrf2 levels of oxidative stress-related proteins in the groups of SWCNH and SWCNH+4-PBA were higher compared to the control group. Moreover, these indicators were higher compared to the group of SWCNH+4-PBA (p < 0.05).DiscussionER stress is the key possible mechanism of CNE2 apoptosis induced by SWCNH. After injury of ERS, SWCNH causes oxidative stress injury, which may eventually lead to apoptosis of CNE2 cells.

Mechanism of dexmedetomidine in brain injury of infant rats via the IRE1α/NF-κB/CHOP pathway

Objective We investigated the mechanism of Dexmedetomidine (Dex) in infant rats with brain injury. Methods The infant rats underwent brain injury modelling. The motor function, spatial learning and memory abilities in rats, and the hippocampal CA1 region Nissl body level and apoptosis were evaluated by behavioural tests and histological stainings. Levels of the hippocampal CA1 region p-IRE1α, nuclear/cytoplasmic p65, CHOP, Bax and Bcl-2 proteins were determined by Western blot. Results Propofol anaesthesia caused brain injury in infant rats. Dex increased the hippocampal CA1 region Nissl body level, abated cell apoptosis, reduced p-IRE1α, ATF6, p-PERK/PERK and CHOP levels, decreased the Bax protein level, elevated the Bcl-2 protein level, and alleviated brain injury in infant rats. After ERS induction and the NF-κB pathway inhibition, the hippocampal CA1 region nuclear/cytoplasmic p65 ratio, CHOP level, and apoptosis were reduced in infant rats with brain injury treated with Dex, while the learning and memory abilities of rats were enhanced. Conclusion Dex reduced the hippocampal CA1 region cell apoptosis and enhanced learning and memory abilities by inhibiting the ERS-mediated IRE1α/NF-κB/CHOP pathway, thereby alleviating brain injury in infant rats.

PKR Inhibitor C16 Regulates HIV-gp120 Induced Neuronal Injury and Cognitive Impairment in Vivo and in Vitro Models.

To study the neuronal protective effect and its potential mechanism of C16 against gp120-induced cognitive impairment in vitro and in vivo. The NORT method was used to evaluate the short-term memory abilities of rats, the morphological changes in hippocampus were observed by Nissl staining. Cell viability and damage degree were detected by MTT and LDH. The cell living/apoptosis status of PC12 cells was determined by AO/EB double staining and the relative mRNA expressions of PKR, IRE1α, JNK, GRP78, and CHOP were detected by RT-qPCR. In comparison with the gp120 + Memantine and gp120 + C16 groups, the rats in the gp120 group showed a significantly decreased discrimination index (P < 0.001), with disordered CA1 region cells and reduced neuron numbers. AO/EB double staining revealed morphological changes in the gp120 and NMDA groups, while cells in the gp120 + C16 and NMDA + C16 groups resembled the control group. And C16 can significantly down-regulate the mRNA expression levels of PKR, IRE1α, JNK, GRP78, and CHOP. (P < 0.05). C16 can reduce the cognitive impairment stimulated by gp120 or NMDA, the protective mechanism may be correlated with inhibiting the upregulation of PKR/IRE1α/JNK pathway and suppressing apoptosis induced by downstream proteins GRP78 and CHOP.

MMP-2 inhibition attenuates ER stress-mediated cell death during myocardial ischemia-reperfusion injury by preserving IRE1α

Endoplasmic reticulum (ER) stress is one of the major events accompanying myocardial ischemia-reperfusion (IR) injury, as hypoxia and oxidative stress disrupt protein folding in the ER. As a result, the unfolded protein response (UPR) is activated through different sensors including inositol-requiring enzyme 1α (IRE1α) and protein kinase R-like ER kinase (PERK). Failure of the UPR to reduce ER stress induces cellular dysfunction. Matrix metalloproteinase-2 (MMP-2) is a ubiquitous protease that is activated intracellularly in response to oxidative stress and partially localizes near the ER. However, its role in ER homeostasis is unknown. We hypothesized that MMP-2 is involved in the regulation of the UPR and ER stress-mediated apoptosis during IR injury. Isolated mouse hearts subjected to IR injury showed impaired recovery of post-ischemic contractile function compared to aerobically perfused controls. Ventricular extracts from IR hearts had higher levels of glucose-regulated protein-78 and protein disulfide isomerase and lower levels of IRE1α and PERK compared to aerobic controls. MMP-2 inhibitors, ARP-100 or ONO-4817, given 10 min before ischemia, improved cardiac post-ischemic recovery and preserved IRE1α level in hearts subjected to 30 min ischemia/40 min reperfusion. IR also increased the levels of CHOP and mitochondrial Bax and caspase-3 and -9 activities, indicating induction of apoptosis, all of which were attenuated by MMP-2 inhibitors, regardless of the reperfusion time. Immunoprecipitation showed an association between MMP-2 and IRE1α in aerobic and IR hearts. During myocardial IR injury MMP-2 may impair the UPR and induce apoptosis by proteolysis of IRE1α. Inhibition of MMP-2 activity protects against cardiac contractile dysfunction in part by preserving IRE1α and preventing the progression to myocardial cell death.

Thiostrepton suppresses colorectal cancer progression through reactive oxygen species related endoplasmic reticulum stress.

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths worldwide. Due to the poor therapeutic efficacy of CRC treatments and poor prognosis of the disease, effective treatment strategies are urgently needed. As long-term proteotoxic stress is a major cause of cell death, agents that induce proteotoxic stress offer a promising strategy for cancer intervention. Thiostrepton is a natural antibiotic derived from the Streptomyces genus. In the present study, we found that thiostrepton triggered apoptosis, reduced the migration of CRC cells, and inhibited xenograft tumour growth in vivo. Mechanistically, thiostrepton reduced proteasome activity; induced the aggregation of ubiquitinated proteins; caused endoplasmic reticulum (ER) stress, which was characterized by increased protein levels of GRP78, ATF4, P-eIF2α, and CHOP and cytosolic calcium release; and ultimately resulted in cell death. Thiostrepton-related changes in cell survival and cell migration, as well as mechanistical processes, were almost completely reversed by treatment with the antioxidant N-acetylcysteine (NAC), suggesting that the mechanism is dependent on reactive oxygen species (ROS). These results demonstrated that thiostrepton induced apoptosis and inhibited migration through ROS-induced ER stress and proteotoxic stress in colorectal cancer.

Comparison of Endoplasmic Reticulum Stress and Pyroptosis Induced by Pathogenic Calcium Oxalate Monohydrate and Physiologic Calcium Oxalate Dihydrate Crystals in HK-2 Cells: Insights into Kidney Stone Formation.

Endoplasmic reticulum stress (ERS) can activate pyroptosis through CHOP and TXNIP; however, the correlation between this process and the formation of kidney stones has not been reported. The purpose is to investigate the effects of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) on ERS and pyroptosis in HK-2 cells and to explore the formation mechanism of calcium oxalate stones. HK-2 cells were injured by 3 μm COM and COD. COM and COD significantly upregulated the expression levels of GRP78, CHOP, TXNIP, and pyroptosis-related proteins (NLRP3, caspase-1, GSDMD-N, and IL-1β). Fluorescence colocalization revealed that COM induced pyroptosis by inducing the interaction between TXNIP and NLRP3. Both COM and COD crystals can induce ERS and pyroptosis in HK-2 cells. COM induces the interaction with NLRP3 by the upregulation of CHOP and TXNIP and then promotes pyroptosis, while COD only promotes pyroptosis by the upregulation of CHOP. The cytotoxicity and the ability of COM to promote crystal adhesion and aggregation are higher than COD, suggesting that COM is more dangerous for calcium oxalate kidney stone formation.

Sinapic acid alleviates glutamate-induced excitotoxicity by inhibiting neuroinflammation and endoplasmic reticulum stress pathway in C6 glioma cells

Sinapic acid (SA) is a polyphenol compound derived from hydroxycinnamic acid found in various foods such as cereals and vegetables and has antioxidant, anti-inflammatory and neuroprotective properties. However, its effects on glutamate-induced excitotoxicity, which is important in neurodegenerative diseases, have not been fully elucidated. This study aimed to investigate the effect of SA on glutamate excitotoxicity and the possible role of proinflammatory cytokines and the endoplasmic reticulum (ER) stress pathway. In the study, C6 rat glioma cell line was used and the cells were divided into 4 groups: control, glutamate, SA and glutamate+SA. Cells were treated with 10 mM glutamate for 24 h to induce excitotoxicity. Additionally, SA was applied to cells at concentrations of 12.5 to 100 μM to examine its effects on glutamate excitotoxicity. XTT test was used for cell viability, and apoptotic cells were determined by immunofluorescence and flow cytometry methods. Proinflammatory cytokines (tumor necrosis factor-alpha, TNF-α and interleukin-beta, IL-1β), ER stress markers (glucose regulatory protein 78, GRP78; C/EBP homologous protein, CHOP and activating transcription factor-4, ATF-4) and caspase-3 was used to measure ELISA method. Findings indicated that SA (50 μM) significantly increased cell viability against glutamate-induced excitotoxicity (p < 0.05). Also, SA caused a significant decrease in TNF-α, IL-1β, GRP78, CHOP, ATF-4 and caspase-3 levels in glutamate-treated cells (p < 0.05). Flow cytometry and immunofluorescence staining results showed that SA reduced apoptosis in C6 glioma cells. In conclusion, our findings suggested that SA attenuated glutamate-induced excitotoxicity by preventing apoptosis through reducing proinflammatory cytokines and ER stress protein levels.

Isoliquiritigenin induced hepatotoxicity and endoplasmic reticulum stress in zebrafish embryos

Isoliquiritigenin (ISL), a naturally occurring flavonoid derived from licorice root, exhibits antioxidant, anticancer, anti-inflammatory, and anti-allergic properties, and is frequently detected in both environmental and human samples. Previous studies from our lab have demonstrated that ISL exposure can lead to developmental deformities and aberrant immune responses. However, the molecular mechanisms underlying ISL toxicity in zebrafish embryos remain incompletely elucidated. Therefore, this study aimed to elucidate the effects of ISL exposure on endoplasmic reticulum (ER) stress in zebrafish embryos by assessing the expression levels of ER stress markers HSPA5 and CHOP, along with associated apoptosis factors, under various ISL concentrations, with tunicamycin (TM) serving as a positive control. Furthermore, targeted analyses of ER stress-related pathways were conducted using RNA transcriptome sequencing, and the up-regulated gene was verified by western blot. The results revealed that ISL exposure significantly elevated the expression levels of HSPA5 and CHOP, concomitantly activating ER stress pathways, including pPERK-eIF2α-ATF4 and ATF6 pathways in zebrafish embryos. These findings suggest that the activation of endoplasmic reticulum stress signaling pathways may contribute to the developmental deformities observed in zebrafish embryos following ISL exposure, thereby highlighting the potential ecological risks associated with ISL usage.

GRK2 mediates cisplatin-induced acute liver injury via the modulation of NOX4

BackgroundThe present study investigated the function of G protein-coupled receptor kinase 2 (GRK2) in acute liver injury (ALI) by cisplatin, and investigated the protective effect of pharmacological inhibition of GRK2.MethodsALI models were generated in global adult hemizygous (ALI-Grk2±) mice and wild-type (WT) mice. Liver biochemistry parameters and histopathology were used to evaluate the severity of ALI and the protective effect of pharmacological inhibition of GRK2. GRK2-siRNA was used to knock down the expression of GRK2 in AML12 cells in vitro.ResultsALI model mice exhibited increased blood levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver pathology accompanied by imbalanced L-glutathione (GSH) levels. Cisplatin administration upregulated GKR2, p-GRK2 and NADPH oxidase 4 (NOX4) expression in the liver tissues of ALI model mice. Compared to WT mice injected with cisplatin, Grk2± mice that received cisplatin showed significant improvements in liver function and pathological performance, decreased NOX4 levels, reduced endoplasmic reticulum (ER) stress, and diminished liver cell apoptosis. In vitro, the transfection of AML12 cells with siRNA significantly reduced NOX4 expression and inhibited cisplatin-induced reactive oxygen species production, ER stress (increased levels of GRP94, GRP78, p-elF2α and CHOP) and apoptotic death. Moreover, pharmacological treatment with drugs that inhibit GRK2 (CP-25 or paroxetine) significantly ameliorated cisplatin-induced ALI by improving liver pathological manifestations, inhibiting oxidative stress and ER stress, and reducing liver cell apoptosis. Similar results were observed in vitro.ConclusionsGRK2 mediates the development of cisplatin-induced ALI by modulating NOX4 and ER stress. Pharmacological inhibition of GRK2 with CP-25 or paroxetine effectively alleviated ALI. GRK2 can be used as a potential target for the prevention and treatment of liver injury.Graphical

MiR-204-5p regulates SIRT1 to promote the endoplasmic reticulum stress-induced apoptosis of inner ear cells in C57BL/6 mice with hearing loss.

This study investigated the effect of miR-204-5p-mediated silencing of SIRT1 on the development of deafness in C57BL/6 mice and the roles of miR-204-5p and SIRT1 in deafness. Auditory brainstem response recordings, H&E staining, and immunohistochemistry were used to observe changes in hearing function and cochlear tissue morphology in 2-month-old and 15-month-old C57BL/6 mice. A senescence model was induced using H2O2 in inner ear cells (HEI-OC1). Changes in HEI-OC1 cell proliferation were detected using the CCK-8 assay, whereas flow cytometry was used to detect changes in apoptosis. MiR-204-5p expression was measured via RT‒qPCR. The SIRT1 agonist RSV and a miR-204-5p inhibitor were used to study changes in ER stress (ERS), proliferation, and apoptosis in HEI-OC1 cells. Western blotting was performed to detect changes in ATF4, CHOP, SIRT1, PERK, p-PERK, Bax, and Bcl-2 protein levels. A dual-luciferase reporter gene assay was carried out to assess the ability of miR-204-5p to target SIRT1. Relative miR-204-5p expression levels in the cochleae of aged C57BL/6 mice increased, whereas SIRT1 expression levels decreased, and miR-204-5p and SIRT1 expression levels were negatively correlated. ERS and increased 8-OHDG levels were observed in aged C57BL/6 mice. In a model of inner ear cell aging, H2O2 treatment induced increases in miR-204-5p expression and ERS-mediated apoptosis. MiR-204-5p was found to target SIRT1 and inhibit its expression. SIRT1 activation and a miR-204-5p inhibitor promoted HEI-OC1 cell proliferation and reduced apoptosis. The miR-204-5p inhibitor regulated expression of the ERS proteins PERK, ATF4, and CHOP to upregulate Bcl-2 and downregulate Bax. This study identified the roles of miR-204-5p and SIRT1 in deafness in C57BL/6 mice and investigated the loss of cochlear outer hair cells and the involvement of apoptosis and ERS in deafness.

SIRT1-Dependent Neuroprotection by Resveratrol in TOCP-Induced Spinal Cord Injury: Modulation of ER Stress and Autophagic Flux.

This study explores the neuroprotective effects of resveratrol (Resv) against tri-o-cresyl phosphate (TOCP)-induced neurotoxicity in the spinal cord of adult hens. It is well documented that TOCP exposure causes significant neurodegeneration via mechanisms that involve endoplasmic reticulum (ER) stress and impaired autophagy. In this experiment, adult hens were assigned to one of four groups: Control, Resv, TOCP, and TOCP + Resv. The spinal cord tissues were examined through transmission electron microscopy, hematoxylin and eosin (HE) staining, Nissl staining, and Western blotting to evaluate key proteins associated with ER stress and autophagy. Additionally, RT-qPCR and immunofluorescence were employed to measure sirtuin1 (SIRT1) expression. The findings revealed that TOCP induced severe ultrastructural damage, including disrupted myelin sheaths, dilated ER, and extensive neurodegeneration, as confirmed by histological evaluations. The expression levels of GRP78, p-PERK, p-eIF2α, ATF4, CHOP, Beclin-1, P62, and LC3-II were also significantly elevated by TOCP. However, Resv treatment markedly attenuated these pathological changes by reducing ER stress, restoring autophagic flux, and upregulating SIRT1 expression, preserving spinal cord integrity. These results indicate that Resv can effectively counteract TOCP-induced neurotoxicity by modulating ER stress and autophagy, underscoring its potential as a therapeutic agent for neuroprotection.

Exploring the dual role of endoplasmic reticulum stress in urological cancers: Implications for tumor progression and cell death interactions.

The endoplasmic reticulum (ER) is crucial for maintaining calcium balance, lipid biosynthesis, and protein folding. Disruptions in ER homeostasis, often due to the accumulation of misfolded or unfolded proteins, lead to ER stress, which plays a significant role in various diseases, especially cancer. Urological cancers, which account for high male mortality worldwide, pose a persistent challenge due to their incurability and tendency to develop drug resistance. Among the numerous dysregulated biological mechanisms, ER stress is a key factor in the progression and treatment response of these cancers. This review highlights the dual role of aberrant ER stress activation in urologic cancers, affecting both tumor growth and therapeutic outcomes. While ER stress can support tumor growth through pro-survival autophagy, it primarily inhibits cancer progression via apoptosis and pro-death autophagy. Interestingly, ER stress can paradoxically aid cancer progression through mechanisms such as exosome-mediated immune evasion. Additionally, the review examines how pharmacological interventions, particularly with phytochemicals, can stimulate ER stress-mediated tumor suppression. Key regulators, including PERK, IRE1α, and ATF6, are discussed for their roles in upregulating CHOP levels and triggering apoptosis. In conclusion, a deeper understanding of ER stress in urological cancers not only clarifies the complex interactions between cellular stress and cancer progression but also provides new opportunities for innovative therapeutic strategies.

Astaxanthin Protects Against H2O2- and Doxorubicin-Induced Cardiotoxicity in H9c2 Rat Myocardial Cells.

Astaxanthin (AST) is a carotenoid that has positive effects on various organs and tissues. It also exhibits a cardioprotective action. In this study, the influence of AST on the survival of H9c2 cardiomyocytes under hydrogen peroxide (H2O2)- and doxorubicin (DOX)-induced cardiotoxicity was investigated. Under these conditions, the content of cytosolic Ca2+ was measured, and changes in the area of the mitochondrial mass, as well as in the content of the voltage-dependent anion channel 1 (VDAC1), the autophagy marker LC3A/B, and the pro-apoptotic transcription factor homologous protein (CHOP), were determined. It was found that AST removed the cytotoxic effect of H2O2 and DOX, while cell survival increased, and the mitochondrial mass did not differ from the control. At the same time, a decrease in the content of cytosolic Ca2+ and the restoration of the VDAC1 level to values close to the control were observed. The restoration of the CHOP level suggests a reduction in endoplasmic reticulum (ER) stress in cells. The results allow us to consider AST as a potential agent in the prevention and/or treatment of cardiac diseases associated with oxidative stress.

Effect of Voluntary Wheel Running on Anxiety- and Depression-Like Behaviors in Fluoride-Exposed Mice.

Fluoride, an environmental toxicant, could induce endoplasmic reticulum stress (ERS) in neuronal cells ultimately leading to apoptosis and emotional dysfunction. Meanwhile, voluntary wheel running contributes to mitigate anxiety and depression. Our investigation aimed to study the effect of voluntary wheel running on anxiety- and depression-like behaviors in fluoride-exposure mice. The results showed that exposure to 100 mg/L sodium fluoride (NaF) for 6 months can induce anxiety- and depression-like behavior in mice. Fluorosis mice subjected to voluntary wheel running have less anxiety- and depression-like behaviors. Nissl and TUNEL staining demonstrated that fluoride led to a reduced proportion of Nissl body area in the cerebral cortex and an increased apoptotic ratio of nerve cells in the cerebral cortex. In contrast, these pathologic damages were improved in voluntary wheel running mice exposed to NaF. Moreover, the expressions of mRNA in the cerebral cortex GABA, GAD65, GAD67, DR, vGLU, 5-HT1A, BDNF, NMDAR1, and Bcl2 were downregulated and the levels of c-fos, GRP78, PERK, eIF2α, CHOP, Caspase-12, and Caspase-3 mRNA were upregulated in mice exposed to fluoride. NaF treatment had increased the PERK, ATF6, IRE1, p-eIF2α, and Caspase-3 protein levels and reduced the expressions of proteins, including GAD67, VGAT, BDNF, NMDAR1, PSD95, and SYN. By contrast, fluorosis mice subjected to voluntary wheel running enhanced the expression of GAD65, GAD67, VGAT, and neuroplasticity-related proteins in mice and inhibited the PERK-CHOP pathway. It is worth noting that the correlation between the amount of exercise and the behavioral indicators as well as neurotransmitter levels was found. In conclusion, voluntary wheel running inhibits the fluoride-induced ERS and GRP78 expression through the PERK-CHOP pathway and plays an anti-apoptotic role, ultimately ameliorating emotional dysfunction in NaF-exposed mice.

Molecular mechanisms of endoplasmic reticulum stress-mediated acute kidney injury in juvenile rats and the protective role of mesencephalic astrocyte-derived neurotrophic factor.

This study examined the role of endoplasmic reticulum stress in pediatric acute kidney injury and the therapeutic effect of midbrain astrocyte-derived neurotrophic factor. Two-week-old Sprague-Dawley rats were divided into: Sham, ischemia-reperfusion injury-induced acute kidney injury (AKI), mesencephalic astrocyte-derived neurotrophic factor (MANF)-treated, tauroursodeoxycholic acid (TUDCA)-treated. Analyses were conducted 24h post-treatment. Serum creatinine, cystatin C, Albumin, MANF levels were measured, cytokine concentrations in serum and renal tissues were determined using a Luminex assay. Histopathology was assessed via light and electron microscopy. Western blotting and RT-qPCR analyzed markers for oxidative stress, apoptosis, endoplasmic reticulum (ER) stress, and autophagy. HK-2 cells underwent hypoxia/reoxygenation (H/R) to simulate AKI and were treated with MANF or TUDCA. AKI rats had increased serum creatinine, cystatin C, and inflammatory cytokines, along with significant renal damage, and showed loose and swollen ER structures, reduced cell proliferation, and elevated levels of IRE1, PERK, ATF6, CHOP, LC3-II/I, KIM-1, TLR4, JNK, and NF-κB. MANF treatment reduced these biomarkers and protein levels, improved ER structure and cell proliferation, alleviated oxidative stress, apoptosis, ER stress, and inhibited JNK/TLR4/NF-κB signaling. In HK-2 cells, MANF reduced ER stress and inflammation post-H/R exposure. MANF treatment alleviates ER stress, oxidative stress, apoptosis, and inflammation in pediatric AKI, improving renal function and morphology.

Particulate matter induced cognitive impairments via endoplasmic reticulum stress-mediated damage to mitochondria-associated endoplasmic reticulum membranes in immature rats

Particulate matter (PM) exposure has been increasingly recognized as detrimental to cognitive function and is associated with neurodevelopmental disorders. Mitochondria-associated endoplasmic reticulum membranes (MAMs) form an integrated interface between mitochondria and the endoplasmic reticulum (ER), facilitating crucial cellular functions. Prolonged ER stress (ERS) is implicated in various pathological states in the nervous system. MAMs and ERS may play vital roles in adverse effects of early-life PM exposure on cognitive abilities. This study investigated whether ERS plays a role in PM-induced MAMs dysfunction, leading to neuronal damage and cognitive impairments in early postnatal rats. Using a rat model with PM exposure concentrations of 2 and 10 mg/kg from postnatal Day 3 (PND3) to PND28, we observed that PM exposure resulted in anxiety-like behavior and impaired spatial working memory. The protein levels of ERS markers, including GRP78 and CHOP, were significantly increased in response to PM exposure. Western blot, transmission electron microscopy (TEM), and immunofluorescence analyses revealed decreased MAMs-related proteins and disrupted MAM structure and function caused by PM exposure. Administration of the ERS inhibitor 4-phenylbutyric acid (4-PBA) ameliorated these effects, restoring MAMs integrity and improving cognitive deficits. These findings highlighted the key role of ERS-MAMs dysfunction in PM-induced neurotoxicity and cognitive impairments, providing a new perspective and strategy for the prevention of cognitive deficits in early age with PM exposure.

Activation of autophagy, paraptosis, and ferroptosis by micheliolide through modulation of the MAPK signaling pathway in pancreatic and colon tumor cells

Micheliolide (MCL), a naturally occurring sesquiterpene lactone, has demonstrated significant anticancer properties through the induction of various programmed cell death mechanisms. This study aimed to explore MCL's effects on autophagy, paraptosis, and ferroptosis in pancreatic and colon cancer cells, along with its modulation of the MAPK signaling pathway. MCL was found to substantially suppress cell viability in these cancer cells, particularly in MIA PaCa-2 and HT-29 cell lines. The study identified that MCL induced autophagy by enhancing the levels of autophagy markers such as Atg7, p-Beclin-1, and Beclin-1, which was attenuated by the autophagy inhibitor 3-MA. Furthermore, MCL was found to facilitate paraptosis, indicated by decreased Alix and in-creased ATF4 and CHOP levels. It also promoted ferroptosis, as demonstrated by the reduced expression of SLC7A11, elevated TFRC levels, and increased intracellular iron. Additionally, MCL activated the MAPK signaling pathway, marked by the phosphorylation of JNK, p38, and ERK, linked with an increase in ROS production that is vital in regulating these cell death mechanisms. These findings propose that MCL is a versatile anticancer agent, capable of activating various cell death pathways by modulating MAPK signaling and ROS levels. These results emphasize the therapeutic promise of MCL in treating cancer, pointing to the necessity of further in vivo investigations to confirm these effects and determine its potential clinical uses.

Curcumin attenuates ochratoxin A and hypoxia co-induced liver injury in grass carp (Ctenopharyngodon idella) by dual targeting endoplasmic reticulum stress and apoptosis via reducing ROS content

BackgroundOchratoxin A (OTA) is a toxin widely found in aquafeed ingredients, and hypoxia is a common problem in fish farming. In practice, aquatic animals tend to be more sensitive to hypoxia while feeds are contaminated with OTA, but no studies exist in this area. This research investigated the multiple biotoxicities of OTA and hypoxia combined on the liver of grass carp and explored the mitigating effect of curcumin (CUR).MethodsA total of 720 healthy juvenile grass carp (11.06 ± 0.05 g) were selected and assigned randomly to 4 experimental groups: control group (without OTA and CUR), 1.2 mg/kg OTA group, 400 mg/kg CUR group, and 1.2 mg/kg OTA + 400 mg/kg CUR group with three replicates each for 60 d. Subsequently, 32 fish were selected, divided into normoxia (18 fish) and hypoxia (18 fish) groups, and subjected to hypoxia stress for 96 h.ResultsCUR can attenuate histopathological damage caused by coming to OTA and hypoxia by reducing vacuolation and nuclear excursion. The alleviation of this damage was associated with the attenuation of apoptosis in the mitochondrial pathway by decreasing the expression of the pro-apoptotic proteins Caspase 3, 8, 9, Bax, and Apaf1 while increasing the expression of the anti-apoptotic protein Bcl-2, and attenuation of endoplasmic reticulum stress (ERS) by reducing Grp78 expression and chop levels. This may be attributed to the fact that the addition of CUR increased the levels of catalase (CAT) and glutathione reductase (GSH), increased antioxidant capacity, and ensured the proper functioning of respiratory chain complexes I and II, which in turn reduced the high production of reactive oxygen species (ROS), thus alleviating apoptosis and ERS.ConclusionsIn conclusion, our data demonstrate the effectiveness of CUR in attenuating liver injury caused by the combination of OTA and hypoxia. This study confirms the feasibility and efficacy of adding natural products to mitigate toxic damage to aquatic animals.