Endoplasmic Reticulum Stress Protein Research Articles

(-)-Epicatechin regulates endoplasmic reticulum stress and promotes ferroptosis in lung cancer cells via the PERK/eIF2α/ATF4 signaling pathway.

(-)-Epicatechin (EC) is an active ingredient of Fagopyrum dibtrys (D. Don) Hara and can regulate lung cancer progression. However, the specific regulatory mechanism is poorly understood. This study explored the specific mechanism of EC in the treatment of lung cancer. H460 cells were injected subcutaneously into the left dorsal sides of nude mice to establish an animal model of lung cancer. H460 and H1299 cells and nude mice were treated with different concentrations of EC. The expression levels of related proteins were detected by Western blotting. Cell proliferation, migration, and invasion were detected by CCK-8, colony formation, and Transwell assays. Flow cytometry was used to detect the Ca2+ level in lung cancer cells. Immunohistochemistry was used to detect the expression of Ki-67 in tumor tissues. This study revealed that ferroptosis in lung cancer cells was inhibited during lung cancer development. EC treatment promotes ferroptosis, inhibits the proliferation, migration and invasion of lung cancer cells, and inhibits the formation of tumors in vivo. Ferroptosis inhibitors (Fer-1) weaken the effects of EC on lung cancer cells, whereas a ferroptosis inducer (erastin) further promotes the effects of EC. In addition, endoplasmic reticulum (ER) stress is involved in the EC-induced ferroptosis of lung cancer cells, and treatment with GSK, an inhibitor of the ER stress protein PERK, can reverse the effect of EC. EC therapy activates the PERK-eIF2α-ATF4 signaling pathway to increase ER stress, thereby promoting ferroptosis in lung cancer cells and inhibiting the occurrence and development of lung cancer. Our research suggests that EC may become a drug candidate for treating lung cancer.

Effects of Epothilone D on Social Defeat Stress-induced Changes in Microtubule-related and Endoplasmic Reticulum Stress Protein Expression

Effects of Epothilone D on Social Defeat Stress-induced Changes in Microtubule-related and Endoplasmic Reticulum Stress Protein Expression

Dietary Probiotic Pediococcus acidilactici GKA4, Dead Probiotic GKA4, and Postbiotic GKA4 Improves Cisplatin-Induced AKI by Autophagy and Endoplasmic Reticulum Stress and Organic Ion Transporters.

Acute kidney injury (AKI) syndrome is distinguished by a quick decline in renal excretory capacity and usually diagnosed by the presence of elevated nitrogen metabolism end products and/or diminished urine output. AKI frequently occurs in hospital patients, and there are no existing specific treatments available to diminish its occurrence or expedite recovery. For an extended period in the food industry, Pediococcus acidilactici has been distinguished by its robust bacteriocin production, effectively inhibiting pathogen growth during fermentation and storage. In this study, the aim is to assess the effectiveness of P. acidilactici GKA4, dead probiotic GKA4, and postbiotic GKA4 against cisplatin-induced AKI in an animal model. The experimental protocol involves a ten-day oral administration of GKA4, dead probiotic GKA4, and postbiotic GKA4 to mice, with a cisplatin intraperitoneal injection being given on the seventh day to induce AKI. The findings indicated the significant alleviation of the renal histopathological changes and serum biomarkers of GKA4, dead probiotic GKA4, and postbiotic GKA4 in cisplatin-induced nephrotoxicity. GKA4, dead probiotic GKA4, and postbiotic GKA4 elevated the expression levels of HO-1 and decreased the expression levels of Nrf-2 proteins. In addition, the administration of GKA4, dead probiotic GKA4, and postbiotic GKA4 significantly reduced the expression of apoptosis-related proteins (Bax, Bcl-2, and caspase 3), autophagy-related proteins (LC3B, p62, and Beclin1), and endoplasmic reticulum (ER) stress-related proteins (GRP78, PERK, ATF-6, IRE1, CHOP, and Caspase 12) in kidney tissues. Notably, GKA4, dead probiotic GKA4, and postbiotic GKA4 also upregulated the levels of proteins related to organic anion transporters and organic cation transporters. Overall, the potential therapeutic benefits of GKA4, dead probiotic GKA4, and postbiotic GKA4 are significant, particularly after cisplatin treatment. This is achieved by modulating apoptosis, autophagy, ER stress, and transporter proteins to alleviate oxidative stress.

The neurotrophic factor MANF regulates autophagy and lysosome function to promote proteostasis in Caenorhabditis elegans

The conserved mesencephalic astrocyte-derived neurotrophic factor (MANF) is known for protecting dopaminergic neurons and functioning in various other tissues. Previously, we showed that Caenorhabditis elegans manf-1 null mutants exhibit defects such as increased endoplasmic reticulum (ER) stress, dopaminergic neurodegeneration, and abnormal protein aggregation. These findings suggest an essential role for MANF in cellular processes. However, the mechanisms by which intracellular and extracellular MANF regulate broader cellular functions remain unclear. We report a unique mechanism of action for MANF-1 that involves the transcription factor HLH-30/TFEB-mediated signaling to regulate autophagy and lysosomal function. Multiple transgenic strains overexpressing MANF-1 showed extended lifespan of animals, reduced protein aggregation, and improved neuronal survival. Using fluorescently tagged MANF-1, we observed tissue-specific localization of the protein, which was dependent on the ER retention signal. Further subcellular analysis showed that MANF-1 localizes within cells to the lysosomes and utilizes the endosomal pathway. Consistent with the lysosomal localization, our transcriptomic study of MANF-1 and analyses of autophagy regulators demonstrated that MANF-1 promotes proteostasis by regulating autophagic flux and lysosomal activity. Collectively, our findings establish MANF as a critical regulator of stress response, proteostasis, and aging.

Fluoride stimulates the MAPK pathway to regulate endoplasmic reticulum stress and heat shock proteins to induce duodenal toxicity in chickens

Fluoride is one of the essential trace elements for body. However, excessive fluoride poses a major threat to human and animal health. Fluorosis may cause pathological damage of the duodenum, but the underlying mechanism needs to be further studied. This study was to investigate the effects of long-term exposure to sodium fluoride (0, 500, 1,000, 2,000 mg/kg) on the duodenum of chickens. The results showed that after NaF exposure, intestinal epithelial cells were disarranged, necrotic or even exfoliated, goblet cells and mucus secretion were increased, and inflammatory response was induced in duodenal tissue. Oxidative stress, endoplasmic reticulum stress (ERs), and heat shock proteins (HSPs) are an adaptive response, however long-term, excessive changes are detrimental. Fluorosis activates ERs through IRE1, PERK and ATF6 pathways, increases the expression of HSP60, HSP70 and HSP90, and causes apoptosis and oxidative damage in duodenal tissue. In addition, fluorosis can activate the MAPK signaling pathway. This article can provide a reference for exploring the potential duodenal toxicity of sodium fluoride.

Investigation of the Immunoexpression of SVIP and UPR Pathway Proteins in Ovarian Adenocarcinoma Cell Line OVCAR-3

Ovarian cancer is the deadliest gynecological cancer. The endoplasmic reticulum (ER), a vital cell organelle, is involved in the folding, synthesis, and modification of a wide range of soluble and insoluble proteins. ER stress initiates the unfolded protein response (UPR), an evolutionary conserved cell stress mechanism. The UPR is mediated by three ER transmembrane sensors: IRE1, ATF6, and PERK. An inhibitor of ERAD is a small VCP/p97-interacting protein (SVIP). The study aimed to investigate the relationship between SVIP and the ER stress protein markers in the human ovarian cancer cell line OVCAR-3. The SVIP and GRP78, PERK, ATF4 immunoexpression levels were analyzed. Furthermore, employing immunofluorescence, the colocalization of three ER sensors and SVIP was ascertained. The immunoexpression of SVIP and GRP78, ATF4, and PERK were shown in the OVCAR-3 cell line. Additionally, immunofluorescence results showed the colocalization of SVIP and UPR-related proteins in the cytoplasm of OVCAR-3 cells. In conclusion, we demonstrated the cellular localization of SVIP and the proteins involved in the UPR pathway. However, further studies are needed to determine the relation between SVIP and these proteins in cancer cells.

The Involvement of Endoplasmic Reticulum Stress during the Interaction between Calcium Oxalate Crystals and Renal Tubular Epithelial Cells.

Our study aimed to elucidate the mechanisms behind the interaction between calcium oxalate (CaOx) crystals and renal tubular epithelial cells through transcriptome sequencing analysis. HK-2 cells were stimulated with or without CaOx monohydrate crystals and subjected to RNA-seq to assess the effects of CaOx crystals on gene expression changes, key pathways, and molecular players during this interaction. A total of 629 differentially expressed genes (DEGs) were identified between the control group and experimental group, with 491 genes up-regulated and 138 down-regulated. Functional enrichment analysis indicated that the DEGs were significantly associated with endoplasmic reticulum stress (ERS) and unfolded protein response. To validate our findings, we compared our results with the public dataset GSE73680 and confirmed the increased expression of two ERS-related DEGs, CHAC1 and FGF21, in renal papillary tissues from patients with CaOx stones. Collectively, these findings suggest that ERS plays a crucial role in the crystal-cell interaction and highlight the potential for developing therapeutic strategies aimed at reducing CaOx stone formation by targeting ERS-related molecules and pathways.

Effects of glial-derived neurotrophic factor on remodeling and mitochondrial function in human airway smooth muscle cells.

Airway smooth muscle (ASM) cells play important roles in airway remodeling of asthma. Our previous studies show that in vivo administration of glial-derived neurotrophic factor (GDNF) in mice induces thickening and collagen deposition in bronchial airways, whereas chelation of GDNF by GFRα1-Fc attenuates airway remodeling in the context of allergen exposure. To determine whether GDNF has direct effects on ASM, in this study, we examined GDNF in ASM cells from normal versus asthmatic humans. We found that GDNF treatment of human ASM cells had only minor effects on cell proliferation and migration, intracellular expression or extracellular deposition of collagen I (COL1), collagen III (COL3), and fibronectin. Endoplasmic reticulum (ER) stress response and mitochondrial function have been implicated in asthma. We investigated whether GDNF regulates these aspects in human ASM. We found that GDNF treatment did not affect ER stress protein expression in normal or asthmatic cells. However, GDNF treatment impaired mitochondrial morphology in ASM but without significant effects on mitochondrial respiration. Thus, it is likely that in vivo effects of GDNF on airway remodeling per se involve cell types other than those on ASM, and thus ASM may serve more as a source of GDNF rather than a target.NEW & NOTEWORTHY Our previous study suggests that glial-derived neurotrophic factor (GDNF) is involved in allergen-induced airway hyperreactivity and remodeling in vivo. Here, we show that GDNF has no direct effects in remodeling of human airway smooth muscle (ASM) but GDNF dysregulates mitochondrial morphology in human ASM in the context of asthma.

Nandrolone Abuse Prior to Head Trauma Mitigates Endoplasmic Reticulum Stress, Mitochondrial Bioenergetic Deficits, and Markers of Neurodegeneration.

The abuse of synthetic steroids, such as nandrolone decanoate (ND), is often associated with violent behavior, increasing the risk of traumatic brain injury (TBI). After a TBI, proteins like APP, β-amyloid peptide-42 (Aβ42), and phosphorylated tau (pTau) accumulate and trigger endoplasmic reticulum (ER) stress associated with an unfolded protein response (UPR). The involvement of mitochondrial bioenergetics in this context remains unexplored. We interrogate whether the abuse of ND before TBI alters the responses of ER stress and mitochondrial bioenergetics in connection with neurodegeneration and memory processing in mice. Male CF1 adult mice were administered ND (15mg/kg) or vehicle (VEH) s.c. for 19days, coinciding with the peak day of aggressive behavior, and then underwent cortical controlled impact (CCI) or sham surgery. Spatial memory was assessed through the Morris water maze task (MWM) post-TBI. In synaptosome preparations, i) we challenged mitochondrial complexes (I, II, and V) in a respirometry assay, employing metabolic substrates, an uncoupler, and inhibitors; and ii) assessed molecular biomarkers through Western blot. TBI significantly increased APP, Aβ42, and pTauSer396 levels, along with ER-stress proteins, GRP78, ATF6, and CHOP, implying it primed apoptotic signaling. Concurrently, TBI reduced mitochondrial Ca2+ efflux in exchange with Na+, disturbed the formation/dissipation of membrane potential, increased H2O2 production, decreased biogenesis (PGC-1⍺ and TOM20), and ATP biosynthesis coupled with oxygen consumption. Unexpectedly, ND abuse before TBI attenuated the elevations in APP, Aβ42, and pTauSer396, accompanied by a decrease in GRP78, ATF6, and CHOP levels, and partial normalization of mitochondrial-related endpoints. A principal component analysis revealed a key hierarchical signature featuring mitochondrial Ca2+ efflux, CHOP, GRP78, TOM20, H2O2, and bioenergetic efficiency as a unique variable (PC1) able to explain the memory deficits caused by TBI, as well as the preservation of memory fitness induced by prior ND abuse.

Post-myocardial infarction heart failure and long-term high-fat diet: Cardiac endoplasmic reticulum stress and unfolded protein response in Sprague Dawley rat model.

Myocardial infarction (MI) significantly contributes to the global mortality rate, often leading to heart failure (HF) due to left ventricular remodeling. Key factors in the pathomechanism of HF include nitrosative/oxidative stress, inflammation, and endoplasmic reticulum (ER) stress. Furthermore, while a high-fat diet (HFD) is known to exacerbate post-MI cardiac remodeling, its impact on these critical factors in the context of HF is not as well understood. This study aimed to assess the impact of post-MI HF and HFD on inflammation, nitro-oxidative stress, ER stress, and unfolded protein response (UPR). The study was performed on fragments of the left ventricle harvested from 30 male adult Sprague Dawley rats, which were divided into four groups based on diet (normal-fat vs. high-fat) and surgical procedure (sham operation vs. coronary artery ligation to induce MI). We assessed body weight, NT-proBNP levels, protein levels related to nitrosative/oxidative stress, ER stress, UPR, apoptosis, and nitric oxide synthases, through Western Blot and ELISA. HFD and MI significantly influenced body weight and NT-proBNP concentrations. HFD elevated 3-nitrotyrosine and myeloperoxidase levels and altered nitric oxide synthase levels. HFD and MI significantly affected ER stress markers and activated or inhibited UPR pathways. The study demonstrates significant impacts of post-MI HF and dietary fat content on cardiac function and stress markers in a rat model. The interaction between HFD and MI on UPR activation suggests the importance of dietary management in post-MI recovery and HF prevention.

Glycidol-induced hepatocyte apoptosis via endoplasmic reticulum stress: The underlying role of the gut-liver axis

Glycidol (CAS: 556-52-5), a known carcinogen and genotoxicant, is often found in refined vegetable oils. Human exposure predominantly occurs through consumption of these oils and their byproducts, which contain glycidyl esters (GEs). Upon ingestion, GEs are metabolized to release glycidol, posing substantial health hazards. Historical studies have reported the tumorigenic properties of glycidol across various organs in mice models, encompassing the stomach, liver, lungs, brain, mammary gland, and skin. In this study, we employed a Balb/c mice model to investigate the hepatotoxic effects of glycidol following exposure to escalating doses (0, 25, 50, and 100 mg/kg bw/day). The hepatotoxicity was evidenced by a significant elevation in liver enzymes (ALT, AST), indicative of liver cell damage. Furthermore, biochemical analysis revealed heightened levels of oxidative stress indicators (SOD, MDA, GSH) and the upregulation of endoplasmic reticulum stress proteins, underscoring the cellular stress response. The induction of hepatocyte apoptosis served as a direct marker of liver damage caused by glycidol exposure. Additionally, glycidol altered the composition of intestinal microbiota and short-chain fatty acids (SCFAs), which unbalanced homeostasis. Gut barrier integrity markers (ZO-1, Claudin-1, Occludin, TLR4, LPS) indicated increased permeability of harmful substances to the liver via the gut-liver axis, which exacerbated hepatic injury. These findings highlight glycidol's disruption of gut homeostasis and its hepatotoxic potential.

Nerolidol- Potential Therapeutic Agent for Various Neurological Disorders via its Antioxidative Property.

Neurological disorders are devastating conditions affecting both cognitive and motorrelated functions in aged people. Yet there is no proper medication to treat these illnesses, and the currently available medications can only provide symptomatic relief to the patients. All neurological disorders share the same etiology, such as oxidative stress, mitochondrial dysfunction, neurochemical deficiency, neuronal loss, apoptosis, endoplasmic reticulum stress, neuroinflammation, and disease-related protein aggregation. Nowadays, researchers use antioxidant-based strategies to prevent or halt the disease progression. Nerolidol, a strong antioxidant, possesses various biological activities and properties that treat cardiotoxicity, nephrotoxicity, neurotoxicity, and many other diseases. Many recent publications and research studies highlight the beneficial effect of nerolidol on brain disorders. In Alzheimer's disease, nerolidol shows neuroprotection by decreasing amyloid plaque formation, lipid peroxidation, cholinergic neuronal loss, locomotor dysfunction, neuroinflammation, and hippocampal damage via enhancing antioxidant expression. Also, it shows neuroprotection against rotenone-induced neurotoxicity by inhibiting microglial activation. Another study reported that nerolidol shows antiepileptic effects in animal models by suppressing kindling-induced memory impairment by decreasing oxidative stress. It has been found that NRL administration increases the antioxidant levels, decreasing the proinflammatory cytokine release as well as decreasing the apoptotic protein and cerebral infarct size. In conclusion, nerolidol tends to reverse the harmful effects of disease-related factors, including OS, neuroinflammation, protein aggregation, and apoptosis, making nerolidol a choiceable drug for the management of neurological disorders. The purpose of this review is to discuss the mechanism of nerolidol in treating various neurological disorders.

Endoplasmic reticulum stress is involved in mycotoxin zearalenone induced inflammatory response, proliferation, and apoptosis in goat endometrial stromal cells

Zearalenone (ZEA) is an estrogen-like mycotoxin and is considered a secondary metabolite produced by Fusarium fungi, which are widely found in the surrounding environment. ZEA has been found to cause reproductive dysfunction in female and male animals, but the underlying mechanism remains unclear. Therefore, this study examined cell proliferation, cell apoptosis, autophagy protein expression, and some inflammatory cytokines such as IL-1β and IL-8 of goat endometrial stromal cells (ESCs) induced by different concentrations (0, 15, 30, 60, and 90 µM) of ZEA. The apoptosis rate was detected by flow cytometry. Western Blot and ELISA assay were used to identify the ER stress signaling pathway and some inflammatory cytokines. Our results revealed that ZEA induced cell proliferation and inhibited cell apoptosis at low and middle concentrations, while at high concentrations of ZEA, cell apoptosis was induced in ESCs. Additionally, ZEA induced the ER stress protein markers such as ATF6, IRE1α, EIF2α, and ATF4. LC3 as a marker of autophagy was up-regulated at all concentrations of ZEA. Moreover, IL-1β and IL-8 showed down-regulation at a low concentration of ZEA, but middle and high concentrations showed up-regulation. In the present study, Knockdown ERN1 can inhibit autophagy and the main markers of ER stress. These results suggest that the IRE1 pathway can reduce apoptosis protein markers, down activate IRE1, and unfolded protein response branches such as ATF6 and LC3 in ESCs. Additionally, IL-1β and IL-8 achieve up-regulation under knockdown IRE1, which can block ER stress markers.

Astaxanthin inhibits apoptosis in a cell model of tauopathy by attenuating endoplasmic reticulum stress and unfolded protein response

The accumulation of misfolded proteins is a common pathological characteristic shared by many neurodegenerative diseases including Alzheimer’s disease and Parkinson’s disease. The disruption of proteostasis triggers endoplasmic reticulum (ER) stress, during which the unfolded protein response (UPR) is initiated by the activation of protein kinase R-like ER kinase (PERK), inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6). These three branches of UPR signals act in concert to reduce the levels of abnormal proteins and restore ER homeostasis. However, the overactivation of UPR impairs cell function and induces apoptosis, which has been implicated in neurodegeneration. Astaxanthin is a xanthophyll carotenoid which has been shown to have neuroprotective effects in both cell and animal models; however, its effects on ER stress and UPR induced by disrupted proteostasis remain unclear. In this study, the effects of astaxanthin on ER stress and cytotoxicity were investigated in N2a cells stably expressing the pro-aggregant tau repeat domain carrying FTDP-17 mutation ΔK280 (Tau4RDΔK280). The results demonstrated that astaxanthin significantly inhibited Tau4RDΔK280-induced loss of cell viability and apoptosis, attenuating Tau4RDΔK280-induced caspase-3 activation and decrease of Bcl-2. Further studies revealed that astaxanthin treatment alleviated Tau4RDΔK280-induced ER stress and suppressed the activation of PERK, IRE1 and ATF6 signaling pathways. These findings suggested that astaxanthin might inhibit Tau4RDΔK280-induced cytotoxicity by attenuating UPR and ER stress. In addition, astaxanthin treatment resulted in a great reduction in the production of intracellular reactive oxygen species and a significant decrease in calcium influx induced by Tau4RDΔK280, which also contributed to the protective effects of astaxanthin against Tau4RDΔK280-induced cytotoxicity.

Mito-LND and (E)-Akt inhibitor-IV: novel compounds inducing endoplasmic reticulum stress and ROS accumulation against hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality. Although multi-kinase inhibitors can prolong the overall survival of late-stage HCC patients, the emergence of drug resistance diminishes these benefits, ultimately resulting in treatment failure. Therefore, there is an urgent need for novel and effective drugs to impede the progression of liver cancer. This study employed a concentration gradient increment method to establish acquired sorafenib or regorafenib-resistant SNU-449 cells. Cell viability was assessed using the cell counting kit-8 assay. A library of 793 bioactive small molecules related to metabolism screened compounds targeting both parental and drug-resistant cells. The screened compounds will be added to both the HCC parental cells and the drug-resistant cells, followed by a comprehensive assessment. Intracellular adenosine triphosphate (ATP) levels were quantified using kits. Flow cytometry was applied to assess cell apoptosis and reactive oxygen species (ROS). Real-time quantitative PCR studied relative gene expression, and western blot analysis assessed protein expression changes in HCC parental and drug-resistant cells. A xenograft model in vivo evaluated Mito-LND and (E)-Akt inhibitor-IV effects on liver tumors, with hematoxylin and eosin staining for tissue structure and immunohistochemistry staining for endoplasmic reticulum stress protein expression. From the compound library, we screened out two novel compounds, Mito-LND and (E)-Akt inhibitor-IV, which could potently kill both parental cells and drug-resistant cells. Mito-LND could significantly suppress proliferation and induce apoptosis in HCC parental and drug-resistant cells by upregulating glycolytic intermediates and downregulating those of the tricarboxylic acid (TCA) cycle, thereby decreasing ATP production and increasing ROS. (E)-Akt inhibitor-IV achieved comparable results by reducing glycolytic intermediates, increasing TCA cycle intermediates, and decreasing ATP synthesis and ROS levels. Both compounds trigger apoptosis in HCC cells through the interplay of the AMPK/MAPK pathway and the endoplasmic reticulum stress response. In vivo assays also showed that these two compounds could significantly inhibit the growth of HCC cells and induce endoplasmic reticulum stress. Through high throughput screening, we identified that Mito-LND and (E)-Akt inhibitor-IV are two novel compounds against both parental and drug-resistant HCC cells, which could offer new strategies for HCC patients.

Endoplasmic reticulum stress of endometrial mesenchymal stem cells in endometriosis

ObjectiveThe human endometrium has significant regenerative abilities due to stem cells, which are vital in immunomodulation, immune tolerance, steroid hormone response, and inflammation. Endometriosis, an inflammatory gynecological disorder where endometrium-like tissue grows outside uterus, affects millions of women and often causes infertility. Recent research indicates that stem cells contribute to pathology of endometriosis. ER stress is implicated in various diseases, including endometriosis. This study aims to examine ER stress in eMSCs within endometriosis pathogenesis and uncover underlying disease mechanisms. MethodsSamples were collected from healthy subjects and women with endometriosis in both proliferative and secretory phases. eMSCs were isolated and characterized via flow cytometry. ER stress protein levels were assessed using proteomic analysis, with validation through Western Blot and immunofluorescence staining. Gene expression was analyzed by RT-qPCR, and ultrastructural examination of eMSCs was conducted using TEM. ER stress markers in tissue samples were detected in SUSD2+ eMSCs through immunofluorescence staining and visualized using a confocal microscope. Statistical analysis was performed using SPSS program. ResultsThe proteomics analysis uncovered ER stress-related proteins (DDRGK1, RTN3, ERp44, TMED2, TMEM33, TMX3) whose levels were significantly distinct from control group. Western Blot analysis and immunofluorescence staining results at protein level; RT-qPCR results at gene level supported these findings. TEM analysis also showed ultrastructural presence of ER stress in endometriosis groups. ConclusionPresence of ER stress in eMSCs in pathogenesis of endometriosis has been demonstrated using various methods. Our research has potential to shed light on pathology of endometriosis and offer promising avenues for non-invasive diagnosis and potential treatment.

A synthetic peptide mimic kills Candida albicans and synergistically prevents infection

More than two million people worldwide are affected by life-threatening, invasive fungal infections annually. Candida species are the most common cause of nosocomial, invasive fungal infections and are associated with mortality rates above 40%. Despite the increasing incidence of drug-resistance, the development of novel antifungal formulations has been limited. Here we investigate the antifungal mode of action and therapeutic potential of positively charged, synthetic peptide mimics to combat Candida albicans infections. Our data indicates that these synthetic polymers cause endoplasmic reticulum stress and affect protein glycosylation, a mode of action distinct from currently approved antifungal drugs. The most promising polymer composition damaged the mannan layer of the cell wall, with additional membrane-disrupting activity. The synergistic combination of the polymer with caspofungin prevented infection of human epithelial cells in vitro, improved fungal clearance by human macrophages, and significantly increased host survival in a Galleria mellonella model of systemic candidiasis. Additionally, prolonged exposure of C. albicans to the synergistic combination of polymer and caspofungin did not lead to the evolution of tolerant strains in vitro. Together, this work highlights the enormous potential of these synthetic peptide mimics to be used as novel antifungal formulations as well as adjunctive antifungal therapy.

Abstract Or126: Targeting ER stress can attenuate arrhythmia in catecholaminergic polymorphic ventricular tachycardia

Gain-of-function mutations of the sarcoplasmic reticulum (SR) Ca 2+ release channel, the ryanodine receptor (RyR2), are linked to the inherited arrhythmia syndrome catecholaminergic polymorphic ventricular tachycardia (CPVT). Increasing evidence suggests that RyR2 gain-of-function not only disturbs intracellular Ca 2+ homeostasis but drives remodeling of cell signaling and ultrastructure that markedly contributes to the arrhythmogenic phenotype. It is well established that disturbed SR Ca 2+ homeostasis can activate the endoplasmic reticulum (ER) stress response, yet whether RyR2 gain-of-function in CPVT drives ER stress is yet to be explored. The goal of our study was to determine the contribution of ER stress evoked by RyR2 gain-of-function to cardiac arrhythmogenesis. To test this, we created a new rat model of CPVT induced by RyR2-S2222L (+/-) mutation. Simultaneous whole cell patch clamp and Ca 2+ imaging demonstrated that under β-adrenergic stimulation, CPVT ventricular myocytes (VMs) exhibit a high propensity to spontaneous Ca 2+ waves (SCWs) and delayed afterdepolarizations. Importantly, CPVT VMs showed increased XBP1 splicing as a marker of ER stress, as well as increased intra-SR redox stress measured using biosensor ER_roGFPiE. Assessment of ER stress proteins that contribute to SR redox status revealed upregulation of H 2 0 2 -producer enzyme ERO1α, with no compensatory change in expression of H 2 O 2 -degrader Peroxiredoxin-4 (PRDX4). Adenoviral overexpression of PRDX4 in CPVT VMs not only normalized SR redox status but attenuated Ca 2+ mishandling, reducing RyR2 activity and the incidence of proarrhythmic spontaneous Ca 2+ waves. Of note, immunofluorescence and biochemical studies suggest a direct interaction between RyR2 and PRDX4. To test whether targeting ER stress was protective at the whole heart level, we delivered AAV9-αMHC-PRDX4 to CPVT rats and performed ex vivo optical mapping. While CPVT hearts exhibited triggered activity and increased incidence of VT, sustained VT was prevented in PRDX4-injected hearts. Collectively, these data strongly suggest that ER stress contributes to the arrhythmogenic phenotype of CPVT. Targeting ER stress protein PRDX4 has promising therapeutic potential to normalize SR homeostasis, stabilize RyR2 activity and attenuate Ca 2+ -dependent arrhythmogenesis.

Abstract Mo029: Angiotensin Receptor Neprilysin Inhibitor improves cardiac hemodynamics and arrhythmogenesis in mitral regurgitation-induced heart failure—from bench to bedside approach

Background: An effective pharmacological therapy yet exists to mitigate mitral regurgitation (MR) progression before surgical interventions. Angiotensin receptor-neprilysin inhibitor (ARNI) has shown benefits in patients with heart failure (HF) with reduced ejection fraction but whether it can reduce degenerative MR induced HF remains unknown. Aim: To test the efficacy of ARNI in improving cardiac function in degenerative MR -induced HF. Methods and Results: Using a novel rat model of degenerative MR, we found that in degenerative MR rats treated with ARNI, left ventricular function and atrial fibrillation (AF) inducibility significantly improved compared with those treated with valsartan only (fractional shortening 61.78±7.26% v.s. 55.07±6.63%). Also, the AF inducibility dropped from 83% to 25% in MR rats treated with ARNI than to 58.3% in those treated with valsartan. ARNI treatment demonstrated significant attenuation of fibrosis, apoptosis and expressions of endoplasmic reticulum (ER) stress and inflammatory-associated proteins in left ventricular tissues compared to valsartan. In a shear stress model, the treatment of ARNI on cardiomyocytes mitigated the flow triggered activities of both ER released calcium signaling and store-operated calcium entry. Parallelly, we prospectively included 65 patients with degenerative MR receiving valsartan or ARNI and followed Holter electrocardiography and echocardiography. Notably, compared with degenerative MR patients receiving valsartan, those prescribed with ARNI demonstrated significant improvement of AF burden and left ventricular function. Conclusions: Degenerative MR-induced cardiovascular dysfunction including fibrosis and ER stress, were more effectively attenuated by ARNI treatment than by valsartan alone.

Activation of NFE2L2 Alleviates Endoplasmic Reticulum Stress-Mediated Pyroptosis in Murine Hippocampus: A Bioinformatics Analysis and Experimental Validation.

Pyroptosis has been implicated in many pathologic processes, including endoplasmic reticulum stress (ERS). However, the underlying mechanisms and molecular targets of ERS affecting pyroptosis still need further exploration. We obtained gene sets associated with ERS and pyroptosis, and the common genes were regarded as crosstalk genes linking ERS and pyroptosis. Protein-protein interaction (PPI) network was constructed, and the hub genes were obtained via Cytoscape. Moreover, to validate the efficacy of the therapeutic target, neurological tests, brain water content measurements, Nissl staining, Western blot, ELISA, TUNEL analyses, and transmission electron microscopy were performed in a mouse model. A total of 13 crosstalk genes were acquired, and enrichment analysis revealed that these genes were mainly enriched in stress-associated cellular processes and pathways, including KEAP1-NFE2L2 pathway. The hub gene, NFE2L2, was identified by Cytoscape, and tert-butylhydroquinone (tBHQ) was screened as candidate drug to activate NFE2L2. Western blot and ELISA results showed that activation of NFE2L2 could attenuate the expression of ERS and pyroptosis-related proteins by promoting nuclear translocation of Nrf2 (encoded by NFE2L2). Pathological evaluation by Nissl staining and TUNEL assay reflected a similar trend. Furthermore, activation of NFE2L2 ameliorated neurological deficits and reduced brain edema. In conclusion, our bioinformatic analysis results established the theoretical foundation of NFE2L2 as a promising therapeutic target. Moreover, in the mouse model, tBHQ pretreatment further confirmed the effectiveness of this target. We hypothesized NFE2L2 may play a key role in the progression of ERS-mediated pyroptosis. These findings may inspire new ideas to treat neurological disorders.