Endoplasmic Reticulum Stress Signaling Research Articles

Short-chain fatty acid butyrate against TMAO activating endoplasmic-reticulum stress and PERK/IRE1-axis with reducing atrial arrhythmia

IntroductionThe accumulation of microbiota-derived trimethylamine N-oxide (TMAO) in the atrium is linked to the development and progression of atrial arrhythmia. Butyrate, a major short-chain fatty acid, plays a crucial role in sustaining intestinal homeostasis and alleviating systemic inflammation, which may reduce atrial arrhythmogenesis. ObjectivesThis study explored the roles of butyrate in regulating TMAO-mediated atrial remodeling and arrhythmia. MethodsWhole-cell patch clamp experiments, Western blotting, and immunocytochemistry were used to analyze electrical activity and signaling, respectively, in TMAO-treated HL-1 atrial myocytes with or without sodium butyrate (SB) administration. Telemetry electrocardiographic recording and echocardiography and Masson’s trichrome staining and immunohistochemistry were employed to examine atrial function and histopathology, respectively, in mice treated with TMAO with and without SB administration. ResultsCompared with control cells, TMAO-treated HL-1 myocytes exhibited reduced action potential duration (APD), elevated sarcoplasmic reticulum (SR) calcium content, larger L-type calcium current (ICa-L), increased Na+/Ca2+ exchanger (NCX) current, and increased potassium current. However, the combination of SB and TMAO resulted in similar APD, SR calcium content, ICa-L, transient outward potassium current (Ito), and ultrarapid delayed rectifier potassium current (IKur) compared with controls. Additionally, TMAO-treated HL-1 myocytes exhibited increased activation of endoplasmic reticulum (ER) stress signaling, along with increased PKR-like ER stress kinase (PERK)/IRE1α axis activation and expression of phospho-IP3R, NCX, and Kv1.5, compared with controls or HL-1 cells treated with the combination of TMAO and SB. TMAO-treated mice exhibited atrial ectopic beats, impaired atrial function, increased atrial fibrosis, and greater activation of ER stress signaling with PERK/IRE1α axis activation compared with controls and mice treated with TMAO combined with SB. ConclusionTMAO administration led to PERK/IRE1α axis activation, which may increase atrial remodeling and arrhythmogenesis. SB treatment mitigated TMAO-elicited ER stress. This finding suggests that SB administration is a valuable strategy for treating TMAO-induced atrial arrhythmia.

Endoplasmic Reticulum Stress Signaling in the Regulation of Hepatic Pathological Responses

Endoplasmic Reticulum Stress Signaling in the Regulation of Hepatic Pathological Responses

Apoptosis-inducing Metabolite from Marine Mangrove Actinobacteria VITGAP173.

Marine actinobacteria have proven to be a remarkable source of bioactive metabolites. The present study focused on the isolation of anticancer metabolites from marine actinobacteria. Streptomyces sp. VITGAP173 was found to have promising anticancer activity against breast cancer cell lines (MCF-7). Bioassay-guided fractionation was followed to identify the bioactive metabolites from crude ethyl acetate extract of VITGAP173, which yielded four fractions. Fraction B exhibited the highest cytotoxic activity against MCF-7 cell lines among the four fractions. Further structural characterization of the fraction was done by FTIR and NMR spectroscopy. The fraction-2 induced cytotoxicity against MCF-7 cell lines and the half maximal inhibition (IC50) value was calculated as 4.7 μg/ml. To elucidate the possible mechanism of cell death, MCF-7 cells were treated with fraction-2 for 24 hours and the morphological changes were examined using acridine orange - ethidium bromide (AO/EB) staining. The fraction also increased the reactive oxygen species (ROS) generation (Flow cytometry, DCFHDA). The molecular mechanism of fraction-induced cell death was analysed by real-time PCR, which revealed that the fraction promotes apoptosis through the CHOP-ATF-4 pathway involved in ER stress signalling. The present findings suggested the apoptosis-inducing potential of fraction-2 in breast cancer therapy.

Qing Hua Chang Yin ameliorates chronic colitis in mice by inhibiting PERK–ATF4–CHOP pathway of ER stress and the NF-κB signalling pathway

Context Ulcerative colitis has been clinically treated with Qing Hua Chang Yin (QHCY), a traditional Chinese medicine formula. However, its precise mechanisms in mitigating chronic colitis are largely uncharted. Objective To elucidate the therapeutic efficiency of QHCY on chronic colitis and explore its underlying molecular mechanisms. Materials and methods A total ion chromatogram fingerprint of QHCY was analysed. Chronic colitis was induced in male C57BL/6 mice using 2% dextran sodium sulphate (DSS) over 49 days. Mice were divided into control, DSS, DSS + QHCY (0.8, 1.6 and 3.2 g/kg/d dose, respectively) and DSS + mesalazine (0.2 g/kg/d) groups (n = 6). Mice were intragastrically administered QHCY or mesalazine for 49 days. The changes of disease activity index (DAI), colon length, colon histomorphology and serum pro-inflammatory factors in mice were observed. RNA sequencing was utilized to identify the differentially expressed transcripts (DETs) in colonic tissues and the associated signalling pathways. The expression of endoplasmic reticulum (ER) stress-related protein and NF-κB signalling pathway-related proteins in colonic tissues was detected by immunohistochemistry staining. Results Forty-seven compounds were identified in QHCY. Compared with the DSS group, QHCY significantly improved symptoms of chronic colitis like DAI increase, weight loss, colon shortening and histological damage. It notably reduced serum levels of IL-6, IL-1β and TNF-α. QHCY suppressed the activation of PERK–ATF4–CHOP pathway of ER stress and NF-κB signalling pathways in colonic tissues. Discussion and conclusions The findings in this study provide novel insights into the potential of QHCY in treating chronic colitis patients.

Eucalyptol Ameliorates Retinal Microvascular Defects through Modulating ER Stress and Angiopoietin-Tie Signaling in Diabetic Eyes.

Loss of the inner blood-retinal barrier (BRB) integrity is a main feature of ocular diseases such as diabetic macular edema. However, there is a lack of clarity on how inner BRB function is modulated within the diabetic retina. The current study examined whether eucalyptol inhibited inner BRB destruction and aberrant retinal angiogenesis in 33 mM glucose-exposed human retinal microvascular endothelial (RVE) cells and db/db mice. This study further examined the molecular mechanisms underlying endothelial dysfunction including retinal endoplasmic reticulum (ER) stress and angiopoietin (Ang)/Tie axis in conjunction with vascular endothelial growth factor (VEGF). Eucalyptol is a naturally occurring monoterpenoid and an achiral aromatic component of many plants including eucalyptus leaves. Nontoxic eucalyptol reduced the production of amyloid-β (Aβ) protein in glucose-loaded RVE cells and in diabetic mice. This natural compound blocked apoptosis of Aβ-exposed RVE cells in diabetic mouse eyes by targeting ER stress via the inhibition of PERK-eIF2α-ATF4-CHOP signaling. Eucalyptol promoted activation of the Ang-1/Tie-2 pathway and dual inhibition of Ang-2/VEGF in Aβ-exposed RVE cells and in diabetic eyes. Supply of eucalyptol reversed the induction of junction proteins in glucose/Aβ-exposed RVE cells within the retina and reduced permeability. In addition, oral administration of eucalyptol reduced vascular leaks in diabetic retinal vessels. Taken together, these findings clearly show that eucalyptol inhibits glucose-induced Aβ-mediated ER stress and manipulates Ang signaling in diabetic retinal vessels, which ultimately blocks abnormal angiogenesis and loss of inner BRB integrity. Therefore, eucalyptol provides new treatment strategies for diabetes-associated RVE defects through modulating diverse therapeutic targets including ER stress, Ang-1/Tie-2 signaling, and Ang-2/VEGF.

Current advances and future prospects of ER stress signaling and its chemical mitigation in plants

Current advances and future prospects of ER stress signaling and its chemical mitigation in plants

Immunologic Crosstalk of Endoplasmic Reticulum Stress Signaling in Bladder Cancer.

Bladder cancer (BC) is a common malignant tumor of the urinary system. While current approaches involving adjuvant chemotherapy, radiotherapy, and immunotherapy have shown significant progress in BC treatment, challenges, such as recurrence and drug resistance, persist, especially in the case of muscle-invasive bladder cancer (MIBC). It is mainly due to the lack of pre-existing immune response cells in the tumor immune microenvironment. Micro-environmental changes (such as hypoxia and under-nutrition) can cause the aggregation of unfolded and misfolded proteins in the lumen, which induces endoplasmic reticulum (ER) stress. ER stress and its downstream signaling pathways are closely related to immunogenicity and tumor drug resistance. ER stress plays a pivotal role in a spectrum of processes within immune cells and the progression of BC cells, encompassing cell proliferation, autophagy, apoptosis, and resistance to therapies. Recent studies have increasingly recognized the potential of natural compounds to exhibit anti-BC properties through ER stress induction. Still, the efficacy of these natural compounds remains less than that of immune checkpoint inhibitors (ICIs). Currently, the ER stress-mediated immunogenic cell death (ICD) pathway is more encouraging, which can enhance ICI responses by mediating immune stemness. This article provides an overview of the recent developments in understanding how ER stress influences tumor immunity and its implications for BC. Targeting this pathway may soon emerge as a compelling therapeutic strategy for BC.

Resveratrol alleviates endoplasmic reticulum stress-induced cell death and improves functional prognosis after traumatic brain injury in mice.

Resveratrol (RSV) is a polyphenol antioxidant that has been shown to have neuroprotective effects. We sought molecular mechanisms that emphasize the anti-inflammatory activity of RSV in traumatic brain injury (TBI) in mice associated with endoplasmic reticulum stress (ERS). After establishing three experimental groups (sham, TBI, and TBI+RSV), we explored the results of RSV after TBI on ERS and caspase-12 apoptotic pathways. The expression levels of C/EBP homologous protein (CHOP), glucose regulated protein 78kD (GRP78), caspase-3, and caspase-12 in cortical brain tissues were assessed by western blotting. The qPCR analysis was also performed on mRNA expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in cortical brain tissue. In addition, the expression of GRP78 in microglia (ionized calcium binding adaptor molecule 1; Iba-1) and neurons (neuronal nuclei; NeuN) was identified by immunofluorescence staining. The neurological function of mice was assessed by modified neurological severity scores (mNSS). After drug treatment, the expression of CHOP, GRP78, caspase-3 and caspase-12 decreased, and qPCR results showed that TNF-α and IL-1β were down-regulated. Immunofluorescence staining showed down-regulation of Iba-1+/GRP78+ and NeuN+/GRP78+ cells after RSV treatment. The mNSS analysis confirmed improvement after RSV treatment. RSV improved apoptosis by downregulating the ERS signaling pathway and improved neurological prognosis in mice with TBI.

Protective roles of thrombomodulin in cisplatin-induced nephrotoxicity through the inhibition of oxidative and endoplasmic reticulum stress

Cisplatin is an effective chemotherapeutic agent widely used for the treatment of various solid tumors. However, cisplatin has an important limitation in its use; currently, there is no method to ameliorate cisplatin-induced acute kidney injury (AKI). Thrombomodulin (TM) is well known not only for its role as a cofactor in the clinically important natural anticoagulation pathway but also for its anti-inflammatory properties. Here, we investigated the effects of TM in cisplatin-induced AKI. In mice intraperitoneally injected with 15 mg/kg cisplatin, TM (10 mg/kg) or PBS was administered intravenously at 24 h after cisplatin injection. TM significantly attenuated cisplatin-induced nephrotoxicity with the suppressed elevation of blood urea nitrogen and serum creatinine, and reduced histological damages. Actually, TM treatment significantly alleviated oxidative stress-induced apoptosis by reducing reactive oxygen species (ROS) levels in cisplatin-treated renal proximal tubular epithelial cells (RPTECs) in vitro. Furthermore, TM clarified cisplatin-induced apoptosis by reducing caspase-3 levels. In addition, TM attenuated the endoplasmic reticulum (ER) stress signaling pathway in both renal tissues and RPTECs to protect the kidneys from cisplatin-induced AKI. These findings suggest that TM is a potential protectant against cisplatin-induced nephrotoxicity through suppressing ROS generation and ER stress in response to cisplatin.

MDB-72. BREFELDIN A (BFA) INDUCES CD133 PROTEOLYTIC PROCESSING IN MEDULLOBLASTOMA STEM CELLS (MBSCS)

Abstract BACKGROUND Medulloblastoma (MB) is a malignant brain tumor occurring in children, characterized by elevated resistance to conventional chemotherapy. Medulloblastoma stem cells (MBSCs) represent a fraction of the tumor cell population which has been associated with poor prognosis and refractoriness to conventional therapies. CD133 (Prominin 1, PROM1) is a transmembrane protein serving as a cancer stem cell marker associated with cancer progression. Brefeldin A (BFA) is an antibiotic disrupting the Golgi apparatus, thus triggering Endoplasmic reticulum (ER) stress signaling pathways. BFA cancer-inhibitory properties have been already described in cancer of different tissue origin. However, the effects of BFA on MBCSs have not been investigated yet. Thus, the aim of this study was to characterize the response of MBSCs to BFA and the effects induced by BFA on CD133. METHODS Human group 3 MB (G3MB) cell lines were grown in stem selective medium (B27™) and treated with 0.3 uM BFA for 24h before collection. Apoptosis, clonogenicity and CD133 expression were evaluated. CD133 was immunoprecipitated and the corresponding bands were excised and analyzed by nanoLC-MS/MS. Raw data were processed using PEAKS XPro. RESULTS Our results show that BFA-treated cells induced the overexpression of a CD133 isoform that was missing the N-terminus region. Moreover, we found a downregulation of CD133 activated intracellular signalling together with a reduced exposition on cell membrane. CONCLUSIONS We report here for the first time, a N-terminus proteolytic processing of CD133, potentially associated to the cell trafficking effects induced by BFA. Finally, this study suggests a proof of principle for the design of novel molecules with similar structures and mechanism of action of BFA.

Regulatory effects of Trichinella spiralis serpin-type serine protease inhibitor on endoplasmic reticulum stress and oxidative stress in host intestinal epithelial cells

Endoplasmic reticulum stress (ERS) and oxidative stress (OS) are adaptive responses of the body to stressor stimulation. Although it has been verified that Trichinella spiralis (T. spiralis) can induce ERS and OS in the host, their association is still unclear. Therefore, this study explored whether T. spiralis-secreted serpin-type serine protease inhibitor (TsAdSPI) is involved in regulating the relationship between ERS and OS in the host intestine. In this study, mice jejunum and porcine small intestinal epithelial cells (IECs) were detected using qPCR, western blotting, immunohistochemistry (IHC), immunofluorescence (IF), and detection kits. The results showed that ERS- and OS-related indexes changed significantly after TsAdSPI stimulation, and Bip was located in IECs, indicating that TsAdSPI could induce ERS and OS in IECs. After the use of an ERS inhibitor, OS-related indexes were inhibited, suggesting that TsAdSPI-induced OS depends on ERS. When the three ERS signalling pathways, ATF6, IRE1, and PERK, were sequentially suppressed, OS was only regulated by the PERK pathway, and the PERK-eif2α-CHOP-ERO1α axis played a key role. Similarly, the expression of ERS-related indexes and the level of intracellular Ca2+ were inhibited after adding the OS inhibitor, and the expression of ERS-related indexes decreased significantly after inhibiting calcium transfer. This finding indicated that TsAdSPI-induced OS could affect ERS by promoting Ca2+ efflux from the endoplasmic reticulum. The detection of the ERS and OS sequences revealed that OS occurred before ERS. Finally, changes in apoptosis-related indexes were detected, and the results indicated that TsAdSPI-induced ERS and OS could regulate IEC apoptosis. In conclusion, TsAdSPI induced OS after entering IECs, OS promoted ERS by enhancing Ca2+ efflux, and ERS subsequently strengthened OS by activating the PERK-eif2α-CHOP-ERO1α axis. ERS and OS induced by TsAdSPI synergistically promoted IEC apoptosis. This study provides a foundation for exploring the invasion mechanism of T. spiralis and the pathogenesis of host intestinal dysfunction after invasion.

Deacetylated MDH1 and IDH1 aggravates PANoptosis in acute liver failure through endoplasmic reticulum stress signaling

Acute liver failure (ALF) is a disease with a high mortality rate and poor prognosis, whose pathogenesis is not fully understood. PANoptosis is a recently proposed mode of cell death characterized by pyroptosis, apoptosis, and necroptosis, but it cannot be explained by any of them alone. This study aims to explore the role of PANoptosis in ALF and the impact and mechanism of deacetylated malate dehydrogenase 1 (MDH1) and isocitrate dehydrogenase 1 (IDH1) on PANoptosis. Our results found that, compared with the control group, the cell viability in the lipopolysaccharide (LPS)/D-galactosamine (D-Gal) group decreased, lactate dehydrogenase (LDH) release increased, cell death increased, and the levels of PANoptosis-related molecules RIPK1, GSDMD, caspase-3, MLKL, IL-18, IL-1β increased, indicating that PANoptosis increased during ALF. Deacetylated MDH1 at K118 and IDH1 at K93 increased the expression of PANoptosis-related molecules RIPK1, GSDMD, caspase-3, MLKL, IL-18, and IL-1β in vivo and in vitro. The deacetylation weakened the inhibitory effect of histone deacetylase (HDAC) inhibitor ACY1215 on PANoptosis-related molecules, suggesting that deacetylated MDH1 at K118 and IDH1 at K93 aggravated PANoptosis during ALF. Deacetylated MDH1 at K118 and IDH1 at K93 also promoted the expression of endoplasmic reticulum stress-related molecules BIP, ATF6, XBP1, and CHOP in vivo and in vitro. The use of endoplasmic reticulum stress inhibitor 4-PBA weakened the promotion effect of deacetylated MDH1 K118 and IDH1 K93 on PANoptosis. The results suggested that deacetylated MDH1 at K118 and IDH1 at K93 may aggravate PANoptosis in ALF through endoplasmic reticulum stress signaling. In conclusion, deacetylated MDH1 and IDH1 may aggravate PANoptosis in ALF, and the mechanism may act through endoplasmic reticulum stress signaling.

Taohong Siwu decoction alleviates cognitive impairment by suppressing endoplasmic reticulum stress and apoptosis signaling pathway in vascular dementia rats

Ethnopharmacological relevanceTaohong Siwu Decoction (TSD), a classic traditional Chinese medicine formula, is used for the treatment of vascular diseases, including vascular dementia (VD). However, the mechanisms remain unclear. Aim of studyThis study aimed to investigate whether TSD has a positive effect on cognitive impairment in VD rats and to confirm that the mechanism of action is related to the Endoplasmic Reticulum stress (ERs) and cell apoptosis signaling pathway. Materials and methodsA total of 40 male adult Sprague-Dawley rats were divided into four groups: sham-operated group (Sham), the two-vessel occlusion group (2VO), the 2VO treated with 4.5 g/kg/d TSD group (2VO + TSD-L), the 2VO treated with 13.5 g/kg/d TSD group (2VO + TSD-H). The rats underwent either 2VO surgery or sham surgery. Postoperative TSD treatment was given for 4 consecutive weeks. Behavioral tests were initiated at the end of gastrulation. Open-field test (OFT) was used to detect the activity level. The New Object Recognition test (NOR) was used to test long-term memory. The Morris water maze (MWM) test was used to examine the foundation of spatial learning and memory. As a final step, the hippocampus was taken for molecular testing. The protein levels of GRP78 (Bip), p-PERK, PERK, IRE1α, p-IRE1α, ATF6, eIF2α, p-eIF2α, ATF4, XBP1, Bcl-2 and Bax were determined by Western blot. Immunofluorescence visualizes molecular expression. ResultsIn the OFT, residence time in the central area was significantly longer in both TSD treatment groups compared to the 2VO group. In the NOR, the recognition index was obviously elevated in both TSD treatment groups. The 2VO group had a significantly longer escape latency and fewer times in crossing the location of the platform compared with the Sham group in MWM. TSD treatment reversed this notion. Pathologically, staining observations confirmed that TSD inhibited hippocampal neuronal loss and alleviated the abnormal reduction of the Nissl body. In parallel, TUNEL staining illustrated that TSD decelerated neuronal apoptosis. Western Blot demonstrated that TSD reduces the expression of ERs and apoptotic proteins. ConclusionIn this study, the significant ameliorative effect on cognitive impairment of TSD has been determined by comparing the behavioral data of the 4 groups of rats. Furthermore, it was confirmed that this effect of TSD was achieved by suppressing the ERs-mediated apoptosis signaling pathway.

Targeting the Ferroptosis and Endoplasmic Reticulum Stress Signaling Pathways by CBX7 in Myocardial Ischemia/reperfusion Injury.

Ferroptosis and endoplasmic reticulum stress (ERS) are common events in the process of myocardial ischemia/reperfusion injury (IRI). The suppression of chromobox7 (CBX7) has been reported to protect against ischemia/reperfusion injury, This research is purposed to expose the impacts and mechanism of CBX7 in myocardial IRI. CBX7 expression was detected using RT-qPCR and western blotting analysis. CCK-8 assay detected cell viability. Inflammatory response and oxidative stress were detected by ELISA, DCFH-DA probe and related assay kits. Flow cytometry analysis and caspase3 activity assay were used to detect cell apoptosis. C11-BODIPY 581/591 staining and ferro-orange staining were used to detect lipid reactive oxygen species (ROS) and Fe2+ level, respectively. Western blotting was used to detect the expression of proteins associated with apoptosis, ferroptosis and ERS. In the hypoxia/reoxygenation (H/R) model of rat cardiomyocytes H9c2, CBX7 was highly expressed. CBX7 interference significantly protected against inflammatory response, oxidative stress, apoptosis, ferroptosis and ERS induced by H/R in H9c2 cells. Moreover, after the pretreatment with ferroptosis activator erastin or ERS agonist Tunicamycin (TM), the protective effects of CBX7 knockdown on the inflammation, oxidative stress and apoptosis in H/R-induced H9c2 cells was partially abolished. To summarize, CBX7 down-regulation may exert anti-ferroptosis and anti-ERS activities to alleviate H/R-stimulated myocardial injury.

Prevotella histicola ameliorates DSS-induced colitis by inhibiting IRE1α-JNK pathway of ER stress and NF-κB signaling

Inflammatory bowel disease (IBD) is a chronic and recurrent gastrointestinal inflammation regulated by intricate mechanisms. Recently, prebiotics is considered as promising nutritional strategy for the prevention and treatment of IBD. Prevotella histicola (P. histicola), an emerging probiotic, possesses apparently anti-inflammatory bioactivity. However, the role and underlying mechanism of P. histicola on IBD remain unclear. Hence, we probe into the effect of P. histicola on dextran sulfate sodium (DSS)-induced colitis and clarified the potential mechanism. Our results revealed that DSS-induced colonic inflammatory response and damaged epithelial barrier in mice were attenuated by oral administration of P. histicola. Moreover, supplementary P. histicola significantly enriched short-chain fatty acid (SCFA)-producing bacteria (Lactobacillus, and Bacillus) and reduced pathogenic bacteria (Erysipelotrichaceae, Clostridium, Bacteroides) in DSS-induced colitis. Notably, In DSS-treated mice, endoplasmic reticulum stress (ERS) was persistently activated in colonic tissue. Conversely, P. histicola gavage suppressed expansion of endoplasmic reticulum, downregulated PERK-ATF4-CHOP and IRE1α-JNK pathway. In vitro, the P. histicola supernatant eliminated LPS-induced higher production of pro-inflammatory cytokines regulated by NF-κB and impairment of epithelial barrier by inhibiting IRE1α-JNK signaling in Caco-2 cell. In summary, our study indicated that P. histicola mitigated DSS-induced chronic colitis via inhibiting IRE1α-JNK pathway and NF-κB signaling. These findings provide the new insights into the promotion of gut homeostasis and the application potential of P. histicola as a prebiotic for IBD in the future.

Temporin-GHaR Peptide Alleviates LPS-Induced Cognitive Impairment and Microglial Activation by Modulating Endoplasmic Reticulum Stress.

Neuroinflammation is considered an important factor that leads to cognitive impairment. Microglia play a crucial role in neuroinflammation, which leads to cognitive impairment. This study aimed at determining whether temporin-GHaR peptide (GHaR) could improve cognitive function and at uncovering the underlying mechanisms. We found that GHaR treatment alleviated LPS-induced cognitive impairment and inhibited activation of microglia in LPS-induced mice. Furthermore, GHaR inhibited activation of endoplasmic reticulum stress (ERS) and the NF-κB signaling pathway in LPS-induced mice. In vitro, GHaR inhibited M1 polarization of BV2 cells and suppressed TNF-α and IL-6 secretion. Additionally, GHaR neuronal cell viability and apoptosis were induced by LPS-activated microglia-conditioned medium. Moreover, in LPS-induced BV2 cells, GHaR inhibited activation of ERS and the NF-κB signaling pathway. In summary, GHaR improved LPS-induced cognitive and attenuated inflammatory responses via microglial activation reversal. In conclusion, the neuroprotective effects of GHaR were mediated via the ERS signaling pathway.

Multi-omics analysis revealed that the protein kinase MoKin1 affected the cellular response to endoplasmic reticulum stress in the rice blast fungus, Magnaporthe oryzae

BackgroundPrevious studies have shown that protein kinase MoKin1 played an important role in the growth, conidiation, germination and pathogenicity in rice blast fungus, Magnaporthe oryzae. ΔMokin1 mutant showed significant phenotypic defects and significantly reduced pathogenicity. However, the internal mechanism of how MoKin1 affected the development of physiology and biochemistry remained unclear in M. oryzae.ResultThis study adopted a multi-omics approach to comprehensively analyze MoKin1 function, and the results showed that MoKin1 affected the cellular response to endoplasmic reticulum stress (ER stress). Proteomic analysis revealed that the downregulated proteins in ΔMokin1 mutant were enriched mainly in the response to ER stress triggered by the unfolded protein. Loss of MoKin1 prevented the ER stress signal from reaching the nucleus. Therefore, the phosphorylation of various proteins regulating the transcription of ER stress-related genes and mRNA translation was significantly downregulated. The insensitivity to ER stress led to metabolic disorders, resulting in a significant shortage of carbohydrates and a low energy supply, which also resulted in severe phenotypic defects in ΔMokin1 mutant. Analysis of MoKin1-interacting proteins indicated that MoKin1 really took participate in the response to ER stress.ConclusionOur results showed the important role of protein kinase MoKin1 in regulating cellular response to ER stress, providing a new research direction to reveal the mechanism of MoKin1 affecting pathogenic formation, and to provide theoretical support for the new biological target sites searching and bio-pesticides developing.

Converging peripheral blood microRNA profiles in Parkinson's disease and progressive supranuclear palsy.

MicroRNAs act via targeted suppression of messenger RNA translation in the DNA-RNA-protein axis. The dysregulation of microRNA(s) reflects the epigenetic changes affecting the cellular processes in multiple disorders. To understand the complex effect of dysregulated microRNAs linked to neurodegeneration, we performed a cross-sectional microRNA expression analysis in idiopathic Parkinson's disease (n = 367), progressive supranuclear palsy (n = 35) and healthy controls (n = 416) from the Luxembourg Parkinson's Study, followed by prediction modelling, enriched pathway analysis and target simulation of dysregulated microRNAs using probabilistic Boolean modelling. Forty-six microRNAs were identified to be dysregulated in Parkinson's disease versus controls and 16 in progressive supranuclear palsy versus controls with 4 overlapping significantly dysregulated microRNAs between the comparisons. Predictive power of microRNA subsets (including up to 100 microRNAs) was modest for differentiating Parkinson's disease or progressive supranuclear palsy from controls (maximal cross-validated area under the receiver operating characteristic curve 0.76 and 0.86, respectively) and low for progressive supranuclear palsy versus Parkinson's disease (maximal cross-validated area under the receiver operating characteristic curve 0.63). The enriched pathway analysis revealed natural killer cell pathway to be dysregulated in both, Parkinson's disease and progressive supranuclear palsy versus controls, indicating that the immune system might play an important role in both diseases. Probabilistic Boolean modelling of pathway dynamics affected by dysregulated microRNAs in Parkinson's disease and progressive supranuclear palsy revealed partially overlapping dysregulation in activity of the transcription factor EB, endoplasmic reticulum stress signalling, calcium signalling pathway, dopaminergic transcription and peroxisome proliferator-activated receptor gamma coactivator-1α activity, though involving different mechanisms. These findings indicated a partially convergent (sub)cellular end-point dysfunction at multiple levels in Parkinson's disease and progressive supranuclear palsy, but with distinctive underlying molecular mechanisms.

Effects of Natural Products through Inhibiting Endoplasmic Reticulum Stress on Attenuation of Idiopathic Pulmonary Fibrosis.

With ever-increasing intensive studies of idiopathic pulmonary fibrosis (IPF), significant progresses have been made. Endoplasmic reticulum stress (ERS)/unfolded protein reaction (UPR) is associated with the development and progression of IPF, and targeting ERS/UPR may be beneficial in the treatment of IPF. Natural product is a tremendous source of new drug discovery, and accumulating studies have reported that many natural products show potential therapeutic effects for IPF via modulating one or more branches of the ERS signaling pathway. Therefore, this review focuses on critical roles of ERS in IPF development, and summarizes herbal preparations and bioactive compounds which protect against IPF through regulating ERS.

PERK specific inhibitor AMG-44 protects against Trimethylamine N-oxide (TMAO)-induced Endoplasmic Reticular Stress and Endothelial Dysfunction

The gut microbiota is known to release metabolites detrimental to the endothelial cell lining of the vascular wall leading to endothelial dysfunction. We have earlier reported that Trimethylamine N-oxide (TMAO), an intestinal microbe derived metabolite, caused endothelial dysfunction. In the present study we hypothesized that protein kinase R-like endoplasmic reticulum kinase (PERK)/eIF2α/ATF4 signaling is involved in TMAO-induced endoplasmic reticular (ER) stress and that treatment with PERK inhibitor AMG-44 protects against TMAO-induced ER stress. The endothelial cells were treated with a range of increasing doses of TMAO (0-300 μM) to induce ER stress. PERK inhibitor AMG-44 (20 – 200nM) was used to treat the TMAO treated and control cells. TAMO showed a dose-dependent upregulation of ER stress marker proteins involved in the PERK/eIF2α/ATF4 ER-stress signaling pathway. Western blot analysis showed significant increase in p-PERK/PERK, p-eIF2α/eIF2α, and IRE1α, AFT-4 protein expression which was further confirmed by immunofluorescent analysis in endothelial cells. Treatment with AMG-44 significantly attenuated the PERK/eIF2α/ATF4 axis also protected against increased endothelial cell permeability induced by TMAO (n=6/group; p<0.05). Our results demonstrate that TMAO-induced endothelial dysfunction via the ER stress-mediated PERK- eIF2 α -ATF4 signaling pathway and that treatment with PERK specific inhibitor AMG-44 could be a novel therapeutic strategy in protection against TMAO-induced ER stress and endothelial dysfunction. NIH R01HL148711 to Dr. Sai Sudha Koka. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.