Amelioration Of Endoplasmic Reticulum Stress Research Articles

A unique compound ameliorating endoplasmic reticulum stress and insulin resistance by binding to β tubulin.

Insulin is secreted by the pancreatic β-cells and regulates glucose uptake. Endoplasmic reticulum (ER) stress is known to induce insulin resistance. Identifying novel compounds, which can ameliorate ER stress and insulin resistance may be beneficial in the treatment of diabetes. Since treatment with compounds sourced from edible plants is relatively safe, this study aimed to identify a plant-derived potential compound attenuating insulin resistance. In the present study, we identified apigenin as an effective compound for ameliorating ER stress and insulin resistance. It attenuated ER stress-induced cell death and hepatic insulin resistance and improved abnormal glucose tolerance in a db/db diabetic model. The molecular mechanism of apigenin involved direct binding to β-tubulin and improving tubulin stability, thereby recovering insulin resistance and developing diabetes. To our knowledge, no known antidiabetic drugs are yet known to target β-tubulin. Edible plants containing apigenins, such as onions, oranges, and parsley, have been consumed since a long time. Therefore, the use of natural edible plants as a source may offer a safe strategy for the prevention of diabetes.

Short-term Uridine Treatment Alleviates Endoplasmic Reticulum Stress via Regulating Inflammation and Oxidative Stress in Lithium-Pilocarpine Model of Status Epilepticus

Status Epilepticus (SE) leads to the development of epilepsy with the contribution of Endoplasmic Reticulum (ER) stress. Uridine, a pyrimidine nucleoside, has been shown to have neuroprotective and antiepileptogenic effects in animal models. This study aimed to determine whether uridine ameliorates ER stress and apoptosis following epileptogenic insult. Secondly, this study aimed to establish the effect of uridine on inflammatory and oxidative stress parameters that contribute to ER stress. Status epilepticus was induced using lithium-pilocarpine in adult male Sprague-Dawley rats. Following SE termination, rats were treated with uridine, 4-phenylbutyric acid (4-PBA), or saline twice daily for 48 h. Expressions of hippocampal glucose-regulated protein 78 (GRP78), Inositol- Requiring Protein 1 (IRE1α), Protein kinase RNA-like Endoplasmic Reticulum Kinase (PERK), and C/EBP Homologous Protein (CHOP) were determined by western blotting 48 h after SE. Uridine's effects on apoptosis, inflammation or oxidation were evaluated by analyses of cleaved caspase-3 and poly(ADP-ribose) polymerase 1 (PARP1) protein expressions or pro-inflammatory cytokine levels or levels of oxidative stress markers, respectively. Expressions of all ER stress-related proteins significantly increased 48 h after SE. Uridine treatment markedly decreased GRP78, IRE1α, and CHOP levels. A decrease in the PERK level was observed following the administration of 4-PBA; however, uridine had no effect. Cleaved caspase-3 and PARP1 levels were increased in the SHAM group, while uridine and 4-PBA treatment effectively decreased their expressions. Treatment with uridine significantly reduced Myeloperoxidase (MPO) and Malondialdehyde (MDA) levels while tending to increase Catalase (CAT) and Glutathione Peroxidase (GPx) levels. Uridine treatment also significantly attenuated levels of TNF-α and IL-1β, the pro-inflammatory cytokines, which increased 48 h post-SE. Our data indicate that uridine alleviates ER stress after SE. This effect may be attributed to the regulation of inflammation and oxidative stress. Uridine shows promise as a potential preventive agent for epilepsy.

Developing p21-activated kinase 1 (PAK1) activators to treat hypertrophic cardiomyopathy (HCM)

Abstract Despite significant progress in comprehending the genetic and metabolic underpinnings of cardiomyocyte dysfunction, there is still a pressing need for targeted treatments to address hypertrophy and progressive remodelling (e.g., fibrosis), seen in HCM1 . PAK1, a regulator of ion channels and myofilaments in cardiomyocytes, has shown promise in curbing pathological hypertrophy2 . Our hypothesis centres on the potential therapeutic benefits of pharmacologically activating PAK1 in managing hypertrophy and adverse remodelling in HCM. First, we conducted virtual screening and kinase assays to identify potent small molecule PAK1 activators, which significantly increased PAK1 activity by 3 to 5-fold, with an EC50 range between 0.5 and 2.5 μΜ. We then evaluated these compounds on cellular hypertrophy in an in vitro model using neonatal rat cardiomyocytes exposed to isoprenaline (ISO). Among those, JB2020A not only prevented ISO-induced hypertrophy, but also reversed pre-existing cellular hypertrophy induced by ISO 24 hours earlier. Subsequently, we assessed the therapeutic potential of JB2020A in a well-characterised HCM mouse model (i.e., Actc1E99K) 3 , known for its rapid disease progression. We initiated a six-week oral treatment regime at 4 weeks of age, dosing at 10 mg/kg per day. Echocardiography and fibrosis evaluation confirmed that JB2020A led to a significant reduction in cardiac hypertrophy and fibrosis with preserved contractile function. Western blotting analysis revealed increased PAK1 phosphorylation and activation in JB2020A-treated E99K hearts, along with a reduction in pro-apoptotic CHOP expression and an upregulation of protective endoplasmic reticulum (ER) response (e.g., ATF4 and Xbp1), indicating an amelioration of ER stress in HCM. These findings underscore the therapeutic potential of small molecule PAK1 activators as a novel approach for addressing hypertrophy and progressive remodelling in HCM.

Fibroblast growth factor 21 attenuates pulmonary ischemia/reperfusion injury via inhibiting endoplasmic reticulum stress-induced ferroptosis though FGFR1/PPARδ signaling pathway

BackgroundAcute lung injury is a critical life-threatening complication of pulmonary and cardiac surgery with a high rate of morbidity and mortality. Fibroblast growth factor 21 (FGF21) has been reported to play an important role in protecting vital organs from damage. This study aims to investigate the potential protective role and mechanism of FGF21 in pulmonary ischemia/reperfusion (I/R)-induced acute lung injury. MethodsA pulmonary epithelial cell line was treated with hypoxia/regeneration (H/R) in vitro and a mouse model of acute lung injury was induced with pulmonary I/R in vivo. Lung injury after pulmonary I/R was compared between FGF21-konckout (KO) mice and wild-type (WT) mice. Recombinant FGF21 was administrated in vivo and in vitro to determine its therapeutic effect. ResultsCirculating levels of FGF21 in mice with pulmonary I/R injury were significantly higher than in those without pulmonary I/R injury. Lung injury was aggravated in FGF21-KO mice compared with WT mice and the administration of FGF21 alleviated lung injury in mouse treated with I/R and pulmonary epithelial cell injury treated with H/R. FGF21 treatment decreased endoplasmic reticulum (ER) stress, Fe2+ and lipid reactive oxygen species (ROS) contents and GPX4 expression and increased PTGS2 levels. Mechanistically, FGF21 upregulated the expression of FGFR1 and PPARδ, ameliorated ER stress and ER stress induced-ferroptosis. Furthermore, FGF21 increased the expression level of PPARδ in pulmonary epithelial cell exposed to H/R, which was inhibited by FGFR1 inhibitor (PD173074). The protective effects of FGF21 were abolished by co-treatment with PPARδ inhibitor (GSK0660), indicating FGF21 attenuated ER stress-induced ferroptosis by dependent on FGFR1/PPARδ signaling pathway. ConclusionOur study reveals that FGF21 protects against pulmonary I/R injury via inhibiting ER stress-induced ferroptosis though FGFR1/PPARδ signaling pathway. Boosting endogenous FGF21 or the administration of recombinant FGF21 could be promising therapeutic strategies for pulmonary IRI.

Irisflorentin improves functional recovery after spinal cord injury by protecting the blood–spinal cord barrier and promoting axonal growth

Spinal cord injury (SCI) induces the disruption of the blood–spinal cord barrier (BSCB) and the failure of axonal growth. SCI activates a complex series of responses, including cell apoptosis and endoplasmic reticulum (ER) stress. Pericytes play a critical role in maintaining BSCB integrity and facilitating tissue growth and repair. However, the roles of pericytes in SCI and the potential mechanisms underlying the improvements in functional recovery in SCI remain unclear. Recent evidence indicates that irisflorentin exerts neuroprotective effects against Parkinson's disease; however, whether it has potential protective roles in SCI or not is still unknown. In this study, we found that the administration of irisflorentin significantly inhibited pericyte apoptosis, protected BSCB integrity, promoted axonal growth, and ultimately improved locomotion recovery in a rat model of SCI. In vitro, we found that the positive effects of irisflorentin on axonal growth were likely to be mediated by regulating the crosstalk between pericytes and neurons. Furthermore, irisflorentin effectively ameliorated ER stress caused by incubation with thapsigargin (TG) in pericytes. Meanwhile, the protective effect of irisflorentin on BSCB disruption is strongly related to the reduction of pericyte apoptosis via inhibition of ER stress. Collectively, our findings demonstrate that irisflorentin is beneficial for functional recovery after SCI and that pericytes are a valid target of interest for future SCI therapies.

Moutan cortex radicis extract alleviates lipid accumulation by modulating endoplasmic reticulum stress in high-fat diet-fed mice

To analyse the effects of Moutan cortex radicis extract (ME) on lipid metabolism disorder via regulation of lipid accumulation and endoplasmic reticulum stress (ERS). C57BL/6 mice were fed an HFD for 11 weeks and then an HFD plus 200 mg/kg ME for 2 weeks. We found that ME reduced hepatic CHOL levels and lipid droplet deposition, and down-regulated PPARγ, SCD1, GRP78 and C/EBP compared to the HFD group (P < 0.05). In the oleic acid-palmitic acid-induced AML12 cell lipid load model, ME addition led to significant reduction in the intracellular TG content, lipid deposition, and mRNA levels of PERK, IRE1, ATF4, CHOP, C/EBP-α, LXRα and ACC (P < 0.05). These findings indicate that ME might be a promising treatment strategy to reverse the lipid metabolism disorder induced by an HFD and that the potential mechanism is associated with a reduction in hepatic lipid accumulation and amelioration of ERS via inhibiting PERK/IRE1-CEBP signaling pathways.

Exploring the therapeutic effects of sulforaphane: an in-depth review on endoplasmic reticulum stress modulation across different disease contexts.

The endoplasmic reticulum (ER) is an intracellular organelle that contributes to the folding of proteins and calcium homeostasis. Numerous elements can disrupt its function, leading to the accumulation of proteins that are unfolded or misfolded in the lumen of the ER, a condition that is known as ER stress. This phenomenon can trigger cell death through the activation of apoptosis and inflammation. Glucoraphanin (GRA) is the predominant glucosinolate found in cruciferous vegetables. Various mechanical and biochemical processes activate the enzyme myrosinase, leading to the hydrolysis of glucoraphanin into the bioactive compound sulforaphane. Sulforaphane is an organosulfur compound that belongs to the isothiocyanate group. It possesses a wide range of activities and has shown remarkable potential as an anti-inflammatory, antioxidant, antitumor, and anti-angiogenic substance. Additionally, sulforaphane is resistant to oxidation, has been demonstrated to have low toxicity, and is considered well-tolerable in individuals. These properties make it a valuable natural dietary supplement for research purposes. Sulforaphane has been demonstrated as a potential candidate drug molecule for managing a range of diseases, primarily because of its potent antioxidant, anti-inflammatory, and anti-apoptotic properties, which can be mediated by modulation of ER stress pathways. This review seeks to cover a wealth of data supporting the broad range of protective functions of sulforaphane, improving various diseases, such as cardiovascular, central nervous system, liver, eye, and reproductive diseases, as well as diabetes, cancer, gastroenteritis, and osteoarthritis, through the amelioration of ER stress in both in vivo and in vitro studies.

Beta-adrenergic stimulation promotes an endoplasmic reticulum stress-dependent inflammatory program in salivary gland epithelial cells.

The effect of beta-adrenergic stimulation on human labial minor salivary gland epithelial cells (LMSGEC) on IL-6 production and its dependency on endoplasmic reticulum (ER) stress were investigated. Primary LMSGEC from Sjögren's syndrome (SS) patients and controls in culture were stimulated with epinephrine and IL-6 expression was evaluated by qPCR and ELISA. The expression of β-ARs in cultured LMSGEC was tested by qPCR, while adrenoceptors and cAMP levels were examined in LMSGs by immunofluorescence. ER evaluation was performed by transmission electron microscopy (TEM) and ER stress by western blot. Epinephrine-induced IL-6 production by cultured LMSGEC was evaluated after alleviation of the ER stress by applying tauroursodeoxycholic acid (TUDCA) and silencing of PKR-like ER kinase (PERK) and activating transcription factor 4 (ATF4) RNAs. Expression of IL-6 by LMSGEC was upregulated after β-adrenergic stimulation, while the silencing of adrenoreceptors downregulated IL-6. The amelioration of ER stress, as well as the silencing of PERK/ATF4, prevented epinephrine-induced upregulation of IL-6. Adrenergic stimulation led to higher and sustained IL-6 levels secreted by LMSGEC of SS patients compared to controls. Adrenergic signaling was endogenously enhanced in LMSGEC of SS patients (expression of β-ARs in situ, intracellular cAMP in cultured LMSGEC). In parallel, SS-LMSGEC expressed dilated ER (TEM) and higher levels of GRP78/BiP. PERK/ATF4 pathway of the ER stress emerged as a considerable mediator of adrenergic stimulation for IL-6 production by the LMSGEC. An enhanced endogenous adrenergic activation and a stressed ER observed in SS-LMSGEC may contribute to a sustained IL-6 production by these cells after adrenergic stimulation.

Hhatl ameliorates endoplasmic reticulum stress through autophagy by associating with LC3

Endoplasmic reticulum (ER) stress, a common cellular stress response induced by various factors that interfere with cellular homeostasis, may trigger cell apoptosis. Autophagy is an important and conserved mechanism for eliminating aggregated proteins and maintaining protein stability of cells, which is closely associated with ER stress and ER stress-induced apoptosis. In this paper, we report for the first time that Hhatl, an ER-resident protein, is downregulated in response to ER stress. Hhatl overexpression alleviated ER stress and ER stress induced apoptosis in cells treated with tunicamycin or thapsigargin, whereas Hhatl knockdown exacerbated ER stress and apoptosis. Further study showed that Hhatl attenuates ER stress by promoting autophagic flux. Mechanistically, we found that Hhatl promotes autophagy by associating with autophagic protein LC3 (microtubule-associated protein 1A/1B-light chain 3) via the conserved LC3-interacting region (LIR) motif. Noticeably, the LIR motif was essential for Hhatl-regulated promotion of autophagy and reduction of ER stress. These findings demonstrate that Hhatl ameliorates ER stress via autophagy activation by interacting with LC3, thereby alleviating cellular pressure. The study indicates that pharmacological or genetic regulation of Hhatl-autophagy signaling might be potential for mediating ER stress and related diseases.

(+)-Lipoic acid reduces mitochondrial unfolded protein response and attenuates oxidative stress and aging in an in vitro model of non-alcoholic fatty liver disease

BackgroundNon-alcoholic fatty liver disease (NAFLD) is a liver disorder characterized by the ac-cumulation of fat in hepatocytes without alcohol consumption. Mitochondrial dysfunction and endoplasmic reticulum (ER) stress play significant roles in NAFLD pathogenesis. The unfolded protein response in mitochondria (UPRmt) is an adaptive mechanism that aims to restore mitochondrial protein homeostasis and mitigate cellular stress. This study aimed to investigate the effects of ( +)-Lipoic acid (ALA) on UPRmt, inflammation, and oxidative stress in an in vitro model of NAFLD using HepG2 cells treated with palmitic acid and oleic acid to induce steatosis.ResultsTreatment with palmitic and oleic acids increased UPRmt-related proteins HSP90 and HSP60 (heat shock protein), and decreased CLPP (caseinolytic protease P), indicating ER stress activation. ALA treatment at 1 μM and 5 μM restored UPRmt-related protein levels. PA:OA (palmitic acid:oleic acid)-induced ER stress markers IRE1α (Inositol requiring enzyme-1), CHOP (C/EBP Homologous Protein), BIP (Binding Immunoglobulin Protein), and BAX (Bcl-2-associated X protein) were significantly reduced by ALA treatment. ALA also enhanced ER-mediated protein glycosylation and reduced oxidative stress, as evidenced by decreased GPX1 (Glutathione peroxidase 1), GSTP1 (glutathione S-transferase pi 1), and GSR (glutathione-disulfide reductase) expression and increased GSH (Glutathione) levels, and improved cellular senescence as shown by the markers β-galactosidase, γH2Ax and Klotho-beta.ConclusionsIn conclusion, ALA ameliorated ER stress, oxidative stress, and inflammation in HepG2 cells treated with palmitic and oleic acids, potentially offering therapeutic benefits for NAFLD providing a possible biochemical mechanism underlying ALA beneficial effects.Graphical

Valsartan Attenuated Homocysteine-Induced Impaired Autophagy and ER Stress in Human Umbilical Vein Endothelial Cells.

Hyperhomocysteinemia is a risk factor for various cardiovascular diseases. However, the mechanism underlying homocysteine- (Hcy-) induced vascular injury remains unclear. The purpose of the present study was to examine a potential mechanism by which Hcy induced injury in human umbilical vascular endothelial cells (HUVEC). The protein abundance of autophagy-related markers was markedly decreased after Hcy treatment, which was associated with endoplasmic reticulum (ER) stress and apoptosis in HUVECs. Protein expression level of angiotensin II type 1 receptor (AT1 receptor) was dramatically increased in response to Hcy. Valsartan, an AT1 receptor blocker, improved autophagy and prevented ER stress and apoptosis in HUVECs treated with Hcy. Consistent with this, silence of AT1 receptor with siRNA decreased the protein abundance of ER stress markers, prevented apoptosis, and promoted autophagy in HUVECs. Inhibition or knockdown of AT1 receptor was shown to be associated with suppression of p-GSK3β/GSK3β-p-mTOR/mTOR signaling pathway. Additionally, inhibition of autophagy by 3-MA aggravated Hcy-induced apoptosis, while amelioration of ER stress by 4-PBA prevented Hcy-induced injury in HUVECs. Hcy-induced HUVEC injury was likely attributed to AT1 receptor activation, leading to impaired autophagy, ER stress, and apoptosis.

Based on Bioinformatics to Explore the Mechanism of "Tangzhiqing" Decoction Alleviating Type 2 Diabetes-associated Cognitive Dysfunction in Mice by Regulating Hippocampal Neuron Apoptosis and Autophagy.

Diabetic cognitive dysfunction (DCD) is emerging as a chronic complication of diabetes that is gaining increasing international recognition. The traditional Chinese medicine (TCM) formulation, Tangzhiqing decoction (TZQ), has shown the capacity to modulate the memory function of mice with DCD by ameliorating insulin resistance. Nevertheless, the precise mechanism underlying the effects of TZQ remains elusive. The chemical constituents of TZQ were screened using TCMSP databases, and DCDassociated disease targets were retrieved from various databases. Subsequently, core targets were identified through network topology analysis. The core targets underwent analysis using Gene Ontology (GO) functional annotations and enrichment in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Models were established through high-fat and high-glucose diet feeding along with intraperitoneal injection of streptozotocin (STZ). TZQ and metformin were administered at varying doses over 8 weeks. The Morris water maze was employed to evaluate the cognitive capabilities of each rat group, while indicators of oxidative stress and insulin were assessed in mice. Neuronal apoptosis in distinct groups of mice's hippocampi was detected using TdT-mediated dUTP Nick-End Labeling (TUNEL), and western blot (WB) analysis was conducted to assess the expression of apoptosis- and autophagy-related proteins, including Bax, Bcl2, Caspase3, Caspase8, Beclin1, ATG7, LC3, p62, and Lamp2, within the hippocampus. TZQ exhibited the capacity to modulate neuronal autophagy, ameliorate endoplasmic reticulum stress, apoptosis, inflammation, and oxidative stress, as well as to regulate synaptic plasticity and conduction. TZQ mitigated cognitive dysfunction in mice, while also regulating hippocampal inflammation and apoptosis. Additionally, it influenced the protein expression of autophagy-related factors such as Bax, Bcl2, Caspase3, Caspase8, Beclin1, ATG7, and LC3. Notably, this modulation significantly reduced neuronal apoptosis in the hippocampus and curbed excessive autophagy. TZQ demonstrated a substantial reduction in neuronal apoptosis within the hippocampus and effectively suppressed excessive autophagy.

Lithium ameliorates spinal cord injury through endoplasmic reticulum stress-regulated autophagy and alleviated apoptosis through IRE1 and PERK/eIF2α signaling pathways

ObjectiveThis study aims to investigate the role of apoptosis and autophagy under endoplasmic reticulum (ER) stress in a lithium-treated SCI model. MethodsWe established a rat thoracic 10 (T10) spinal cord contusion model and observed its therapeutic effect by intraperitoneal (IP) injection of lithium. Histological and behavioral recovery with or without lithium injection were evaluated after rat spinal cord injury. In addition, we employed an oxygen-glucose deprivation (OGD)-PC12 cell model to study the effects of lithium on OGD-PC12 cell apoptosis, autophagy and ER stress. ResultsWe found that lithium administration to SCI rats reduced neuronal apoptosis and autophagy, restored rat locomotor function by reducing ER stress via IRE1 and PERK/eIF2α pathways. In vitro experiments confirmed that upon lithium treatment, OGD-PC12 cells resisted ER stress caused by thapsigargin (TG) via the IRE1 and PERK/eIF2α signaling pathways. ConclusionLithium attenuated neuronal apoptosis and autophagy, and facilitates the recovery after spinal cord injury through ameliorating ER stress, providing a new therapeutic mechanism for lithium to treat SCI.

Exosomes Derived from M2 Microglial Cells Modulated by 1070-nm Light Improve Cognition in an Alzheimer's Disease Mouse Model.

Near-infrared photobiomodulation has been identified as a potential strategy for Alzheimer's disease (AD). However, the mechanisms underlying this therapeutic effect remain poorly characterize. Herein, it is illustrate that 1070-nm light induces the morphological alteration of microglia from an M1 to M2 phenotype that secretes exosomes, which alleviates the β-amyloid burden to improve cognitive function by ameliorating neuroinflammation and promoting neuronal dendritic spine plasticity. The results show that 4Jcm-2 1070-nm light at a 10-Hz frequency prompts microglia with an M1 inflammatory type to switch to an M2 anti-inflammatory type. This induces secretion of M2 microglial-derived exosomes containing miR-7670-3p, which targets activating transcription factor 6 (ATF6) during endoplasmic reticulum (ER) stress. Moreover, it is found that miR-7670-3p reduces ATF6 expression to further ameliorate ER stress, thus attenuating the inflammatory response and protecting dendritic spine integrity of neurons in the cortex and hippocampus of 5xFAD mice, ultimately leading to improvements in cognitive function. This study highlights the critical role of exosomes derive from 1070-nm light-modulated microglia in treating AD mice, which may provide a theoretical basis for the treatment of AD with the use of near-infrared photobiomodulation.

LRRK2 Gly2019Ser Mutation Promotes ER Stress via Interacting with THBS1/TGF-β1 in Parkinson's Disease.

The gene mutations of LRRK2, which encodes leucine-rich repeat kinase 2 (LRRK2), are associated with one of the most prevalent monogenic forms of Parkinson's disease (PD). However, the potential effectors of the Gly2019Ser (G2019S) mutation remain unknown. In this study, the authors investigate the effects of LRRK2 G2019S on endoplasmic reticulum (ER) stress in induced pluripotent stem cell (iPSC)-induced dopamine neurons and explore potential therapeutic targets in mice model. These findings demonstrate that LRRK2 G2019S significantly promotes ER stress in neurons and mice. Interestingly, inhibiting LRRK2 activity can ameliorate ER stress induced by the mutation. Moreover, LRRK2 mutation can induce ER stress by directly interacting with thrombospondin-1/transforming growth factor beta1 (THBS1/TGF-β1). Inhibition of LRRK2 kinase activity can effectively suppress ER stress and the expression of THBS1/TGF-β1. Knocking down THBS1 can rescue ER stress by interacting with TGF-β1 and behavior burden caused by the LRRK2 mutation, while suppression of TGF-β1 has a similar effect. Overall, it is demonstrated that the LRRK2 mutation promotes ER stress by directly interacting with THBS1/TGF-β1, leading to neural death in PD. These findings provide valuable insights into the pathogenesis of PD, highlighting potential diagnostic markers and therapeutic targets.

P-Nrf2/HO-1 Pathway Involved in Methamphetamine-induced Executive Dysfunction through Endoplasmic Reticulum Stress and Apoptosis in the Dorsal Striatum.

Methamphetamine (METH) abuse is known to cause executive dysfunction. However, the molecular mechanism underlying METH induced executive dysfunction remains unclear. Go/NoGo experiment was performed in mice to evaluate METH-induced executive dysfunction. Immunoblot analysis of Nuclear factor-E2-related factor 2 (Nrf2), phosphorylated Nrf2 (p-Nrf2), heme-oxygenase-1 (HO-1), Glucose Regulated Protein 78(GRP78), C/EBP homologous protein (CHOP), Bcl-2, Bax and Caspase3 was performed to evaluate the levels of oxidative stress, endoplasmic reticulum (ER) stress and apoptosis in the dorsal striatum (Dstr). Malondialdehyde (MDA) levels and glutathione peroxidase (GSH-Px) activity was conducted to evaluate the level of oxidative stress. TUNEL staining was conducted to detect apoptotic neurons. The animal Go/NoGo testing confirmed that METH abuse impaired the inhibitory control ability of executive function. Meanwhile, METH down-regulated the expression of p-Nrf2, HO-1 and GSH-Px and activated ER stress and apoptosis in the Dstr. Microinjection of Tert-butylhydroxyquinone (TBHQ), an Nrf2 agonist, into the Dstr increased the expression of p-Nrf2, HO-1, and GSH-Px, ameliorated ER stress, apoptosis and executive dysfunction caused by METH. Our results indicated that the p-Nrf2/HO-1 pathway was potentially involved in mediating methamphetamine-induced executive dysfunction by inducing endoplasmic reticulum stress and apoptosis in the dorsal striatum.

Protective Effect of Hawthorn Fruit Extract against High Fructose-Induced Oxidative Stress and Endoplasmic Reticulum Stress in Pancreatic β-Cells

Hyperglycemia has deleterious effects on pancreatic β-cells, causing dysfunction and insulin resistance that lead to diabetes mellitus (DM). The possible causes of injury can be caused by glucose- or fructose-induced oxidative and endoplasmic reticulum (ER) stress. Hawthorn (Crataegus pinnatifida) fruit has been widely used as a hypolipidemic agent in traditional herbal medicine. The study aimed to investigate whether high fructose-induced pancreatic β-cell dysfunction could be reversed through amelioration of ER stress by the treatment of polyphenol-enriched extract (PEHE) from hawthorn fruit. The extract was partitioned using ethyl acetate as a solvent from crude water extract (WE) of hawthorn fruits, followed by column fractionation. The results showed that the contents of total polyphenols, flavonoids and triterpenoids in PEHE could be enhanced by 2.2-, 7.7- and 1.1-fold, respectively, in comparison to the original obtained WE from hawthorn fruit. In ER stress studies, a sharp increase in the inhibitory activity on the gene expression levels of GRP79, ATF6, IRE1α and CHOP involved in ER stress was evident when dosages of PEHE at 50-100 μg/mL were used against high-fructose (150 mM)-treated cells. HPLC-MS/MS analysis showed that polyphenols and flavonoids collectively accounted for 87.03% of the total content of PEHE.

Astaxanthin treatment ameliorates ER stress in polycystic ovary syndrome patients: a randomized clinical trial

Astaxanthin (ASX), as a natural carotenoid compound, exists in various types of seafood and microorganisms. It has several possible beneficial therapeutic effects for patients with polycystic ovary syndrome (PCOS). Patients with PCOS also suffer from endoplasmic reticulum (ER) stress. In the present work, it was hypothesized that ER stress could be improved by ASX in PCOS patients. Granulosa cells (GCs) were obtained from 58 PCOS patients. The patients were classified into ASX treatment (receiving 12 mg/day for 60 days) and placebo groups. The expression levels of ER stress pathway genes and proteins were explored using Western blotting and quantitative polymerase chain reaction. To assess oxidative stress markers, follicular fluid (FF) was gained from all patients. The Student’s t test was used to perform statistical analysis. After the intervention, ASX led to a considerable reduction in the expression levels of 78-kDa glucose-regulated protein (GRP78), CCAAT/enhancer-binding protein homologous protein (CHOP), and X-box-binding protein 1 compared to the placebo group, though the reduction in the messenger RNA (mRNA) expression level of activating transcription factor 6 was not statistically significant. However, ASX significantly increased the ATF4 expression level. GRP78 and CHOP protein levels represented a considerable decrease in the treatment group after the intervention. In addition, a statistically significant increase was found in the FF level of total antioxidant capacity in the treatment group. Based on clinical outcomes, no significant differences were found between the groups in terms of the oocyte number, fertilization rate, and fertility rate, but the ASX group had higher rates of high-quality oocytes, high-quality embryo, and oocyte maturity compared to the placebo group. Our findings demonstrated that ER stress in the GCs of PCOS patients could be modulated by ASX by changing the expression of genes and proteins included in the unfolding protein response.Trial registration This study was retrospectively registered on the Iranian Registry of Clinical Trials website (www.irct.ir; IRCT-ID: IRCT20201029049183N, 2020-11-27).

Loss of DDRGK1 impairs IRE1α UFMylation in spondyloepiphyseal dysplasia.

Spondyloepiphyseal dysplasia (SEMD) is a rare disease in which cartilage growth is disrupted, and the DDRGK1 mutation is one of the causative genes. In our study, we established Ddrgk1fl/fl, Col2a1-ERT Cre mice, which showed a thickened hypertrophic zone (HZ) in the growth plate, simulating the previous reported SEMD pathology in vivo. Instead of the classical modulation mechanism towards SOX9, our further mechanism study found that DDRGK1 stabilizes the stress sensor endoplasmic reticulum-to-nucleus signaling 1 (IRE1α) to maintain endoplasmic reticulum (ER) homoeostasis. The loss of DDRGK1 decreased the UFMylation and subsequently led to increased ubiquitylation-mediated IRE1α degradation, causing ER dysfunction and activating the PERK/CHOP/Caspase3 apoptosis pathway. Further DDRGK1 K268R-mutant mice revealed the importance of K268 UFMylation site in IRE1α degradation and subsequent ER dysfunction. In conclusion, DDRGK1 stabilizes IRE1α to ameliorate ER stress and following apoptosis in chondrocytes, which finally promote the normal chondrogenesis.

Melatonin Offers Dual-Phase Protection to Brain Vessel Endothelial Cells in Prolonged Cerebral Ischemia-Recanalization Through Ameliorating ER Stress and Resolving Refractory Stress Granule.

Ischemic-reperfusion injury limits the time window of recanalization therapy in cerebral acute ischemic stroke (AIS). Brain vessel endothelial cells (BVECs) form the first layer of the blood-brain barrier (BBB) and are thus the first sufferer of ischemic-reperfusion disorder. The current study demonstrates that melatonin can reduce infarct volume, alleviate brain edema, ameliorate neurological deficits, and protect BBB integrity in prolonged-stroke mice. Here, we demonstrate that endoplasmic reticulum (ER)-associated injury contributes to BVEC death in the dural phase of reperfusion after prolonged ischemia. When encountering ischemia, ER stress arises, specifically activating PERK-EIF2α signaling and the subsequent programmed cell death. Prolonged ischemia leads stress granules (SGs) to be refractory, which remain unresolved and accumulate in ER during recanalization. During reperfusion, refractory SGs activate PKR-EIF2α and further exacerbate BVEC injury. We report that melatonin treatment downregulates ER stress in the ischemic period and enhances dissociation of the refractory SGs during reperfusion, thus offering dual-phase protection to BVECs in prolonged cerebral stroke. Mechanistically, melatonin enhances autophagy in BVECs, which preserves ER function and resolves refractory SGs. We, therefore, propose that melatonin is a potential treatment to extend the time window of delayed recanalization therapy in AIS.