Reshaping endoplasmic reticulum quality control through the unfolded protein response

Protein disulphide isomerase A4 as a potential biomarker for coronavirus disease 2019: Correlation with cytokine profiles and disease progression

This study investigated the role of protein disulphide isomerase A4 (PDIA4) in the pathogenesis of coronavirus disease 2019 (COVID-19), focusing on its relationship with disease severity and potential as a biomarker. We analysed a cohort of adult COVID-19 patients with varying disease severity, grouped by vaccination status. Serum levels of PDIA4 and cytokines (interleukin [IL]-6, interferon gamma inducible protein-10 [IP-10], IL-16, monocyte chemoattractant protein-1 [MCP-1], and platelet-derived growth factor-BB [PDGF-BB]) were measured using enzyme-linked immunosorbent assay and compared among patients with different disease severities. Statistical analyses were performed to assess the correlation between PDIA4 levels, disease severity, and inflammatory markers. Unvaccinated COVID-19 patients with pneumonia had significantly higher PDIA4 levels than those without pneumonia (517.94 ± 264 vs. 284.86 ± 2.24; p = 0.0022). Although unvaccinated patients requiring oxygen support exhibited higher PDIA4 levels than those not requiring oxygen (519.30 ± 269.67 vs. 420.89 ± 240.49; p = 0.4825), the difference was not statistically significant. No significant difference was observed in the PDIA4 levels between unvaccinated patients with and without respiratory failure. Levels of PDIA4 were positively correlated with the levels of IL-16, MCP-1, IP-10, and IL-6 (correlation coefficients: 0.28-0.62), although this correlation was weaker or absent in vaccinated patients. Our findings suggest that PDIA4 is associated with COVID-19 severity and may serve as a potential biomarker of disease progression. Further studies are needed to elucidate the mechanisms by which PDIA4 influences the immune response and assess its potential for therapeutic exploration in COVID-19.

Inhibition of α-synuclein aggregation by MCC950 attenuates dopaminergic neuronal damage in MN9D cells

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons and the pathological aggregation of α-synuclein, which drives neurodegeneration. The NLRP3 inflammasome inhibitor MCC950 has shown neuroprotective effects in various PD models, but its direct impact on α-synuclein aggregation remains unclear. Here, we investigated the effects of MCC950 in an α-synuclein-overexpressing MN9D dopaminergic neuronal model. MCC950 significantly alleviated α-synuclein-induced neuronal damage, as evidenced by improved cell viability, reduced apoptosis, and downregulated tumor necrosis factor-alpha (TNF-α) expression. Proteomic analysis revealed that MCC950 modulates protein processing in the endoplasmic reticulum (ER), potentially alleviating stress-induced protein misfolding. Molecular docking and biochemical assays demonstrated that MCC950 directly binds to the C-terminal region of α-synuclein, inhibiting its aggregation. Additionally, MCC950 upregulated heat shock protein 70 (HSP70), a molecular chaperone that suppresses α-synuclein oligomerization. Notably, the neuroprotective effects of MCC950 were independent of autophagy modulation or NLRP3 inflammasome inhibition in this model. These findings highlight MCC950 as a multi-target therapeutic agent that directly inhibits α-synuclein aggregation, offering a promising strategy for treating PD and related α-synucleinopathies.

Kinsenoside attenuates ER stress and inhibits inflammatory responses through IL-10/STAT/SOCS3 pathway in chronic pain relief

Neuro-inflammation contributes to neuropathic pain by sensitizing ionic channels. Kinsenoside, a traditional Chinese medicine, has recognized anti-inflammatory properties. However, it remains unclear whether kinsenoside can be used for pain therapy. Network pharmacology analysis revealed that 57 % of its targets are associated with pain, including inflammation and synaptic transmission. The analgesic effects of kinsenoside were confirmed in SNL and formalin rat models, with ED50 values of 47.99 μg and 36.80 μg, respectively. Transcriptome and WGCNA analyses indicated the involvement of cytokine release, anti-inflammatory activity, and synapse enrichment in the blue module. Furthermore, we confirmed that kinsenoside's efficacy was mainly mediated by IL-10 induction, phosphorylation of STAT3, and SOCS3 expression. Pretreatment with kinsenoside significantly inhibited the release of TNF-α, IL-1β, and IL-6. Kinsenoside also attenuated ER stress in both microglia and neural cells. Molecular docking analysis demonstrated significantly high binding energies of IL-10, STAT3, and SOCS3 with MHC. Additionally, whole-cell recordings revealed that bath application of kinsenoside reduced the frequency and amplitude of spinal glutamatergic transmission in a dose-dependent manner. In summary, pharmacological prediction and biological validation collectively indicate that kinsenoside significantly exerts significant analgesic effects by attenuating ER stress and inhibiting inflammatory responses via the IL-10/p-STAT3/SOCS3 axis, precisely regulating spinal glutamatergic transmission for pain relief.

Mechanism and engineering of endoplasmic reticulum-localized membrane protein folding in Saccharomyces cerevisiae

Correct folding of endoplasmic reticulum (ER)-localized membrane proteins, such as cytochrome P450, endows a synthetic biology host with crucial catalytic functions, which is of vital importance in the field of metabolic engineering and synthetic biology. However, due to complexed interaction with cellular membrane environment and other proteins (e.g., molecular chaperone) regulation, a substantial proportion of heterologous membrane proteins cannot be properly folded in the ER of Saccharomyces cerevisiae, a widely used synthetic biology host. In this review, we first introduce the four steps in membrane protein folding process and the affecting factors including the amino acid sequence of membrane protein, the folding process, molecular chaperones, quality control mechanism, and lipid environment in S. cerevisiae. Then, we summarize the metabolic engineering strategies to enhance the correct folding of ER-localized membrane proteins, such as by engineering and de novel design of membrane protein, regulation of the co-translational folding process, co-expression of molecular chaperones, modulation of ER quality, and lipids engineering. Finally, we discuss the limitations of current strategies and propose future research directions to address the key issues.

Hexosamine biosynthesis dysfunction-induced LIFR N-glycosylation deficiency exacerbates steatotic liver ischemia/reperfusion injury

BACKGROUND

More and more steatotic livers undergo resection or transplantation but they exhibit higher susceptibility to ischemia-reperfusion injury (IRI), which results in increased perioperative complication morbidity and mortality. IRI is driven by various cytokines and receptors, both of which are extensively modified by N-glycosylation. We aim to elucidate susceptibility of steatotic livers to IRI from the perspective of N-glycosylation.

METHODS

Differentially expressed genes and glycoproteins were identified with RNA-seq and N-glycoproteomics. Myeloid LIF or hepatocyte LIFR knockout mice were developed to examine the function of LIF and LIFR. Modalities including phosphoproteomics, ChIP-seq, single cell RNA-seq, metabolomics and immunoblotting were utilized to investigate underlying mechanisms.

RESULTS

LIF transcription in myeloid cells and LIFR N-glycosylation in hepatocytes were substantially induced by IRI of normal livers. LIF and LIFR protected normal livers from IRI through activating STAT3 and promoting downstream TNFAIP3 expression, which was facilitated by LIFR N-glycosylation. Mechanistically, N-glycosylation at N238 stabilized LIFR protein by disrupting TRIM28-mediated K48 ubiquitination at LIFR K254. Furthermore, N-glycosylation at N358/N658/N675 of LIFR facilitated LIF/LIFR/gp130 complex formation and subsequent signal transduction. However, in steatotic livers, myeloid cell LIF transcription was partially inhibited due to hepatic microenvironment L-arginine insufficiency, while hepatocyte LIFR N-glycosylation was defective due to intracellular UDP-GlcNAc exhaustion. Importantly, combined L-arginine and GlcNAc treatment reversed LIF expression and LIFR N-glycosylation insufficiency, which represents potential therapeutic strategy to protect steatotic livers.

CONCLUSIONS

LIF expression and LIFR N-glycosylation insufficiency aggravates steatotic liver IRI, which can be reversed by combined L-arginine and GlcNAc treatment.

Resting Ca2+ fluxes protect cells from fast mitochondrial fragmentation, cell stress responses, and immediate transcriptional reprogramming

Homeostatic calcium ion (Ca2+) fluxes between the endoplasmic reticulum, cytosol, and extracellular space occur not only in response to cell stimulation but also in unstimulated cells. Using murine astrocytes as a model, we asked whether there is a signaling function of these resting Ca2+ fluxes. The data showed that endoplasmic reticulum (ER) Ca²⁺ depletion, induced by sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) inhibition, resulted to prolonged Ca²⁺ influx and mitochondrial fragmentation within 10 to 30 min. This mitochondrial fragmentation could be prevented in Ca2+-free medium or by inhibiting store-operated Ca2+ entry (SOCE). Similarly, attenuation of STIM proteins, which are vital ER Ca2+ sensors, protected mitochondrial morphology. On the molecular level, ER Ca2+ depletion, achieved either by removing extracellular Ca2+ or through acute SERCA inhibition, led to changes in gene expression of about 13% and 41% of the transcriptome within an hour, respectively. Transcriptome changes were associated with universal biological processes such as transcription, differentiation, or cell stress. Strong increase in expression was observed for the transcription factor ATF4, which is under control of the kinase PERK (EIF2AK3), a key protein involved in ER stress. Corroborating these findings, PERK was rapidly phosphorylated in Ca2+-free medium or after acute pharmacological inhibition of SOCE. In summary, resting, homeostatic Ca2+ fluxes prevent immediate-early cell stress and transcriptional reprogramming.

Crosstalk between ferroptosis and endoplasmic reticulum stress: A potential target for ovarian cancer therapy (Review)

Ferroptosis is a unique mode of cell death driven by iron‑dependent phospholipid peroxidation, and its mechanism primarily involves disturbances in iron metabolism, imbalances in the lipid antioxidant system and accumulation of lipid peroxides. Protein processing, modification and folding in the endoplasmic reticulum (ER) are closely related regulatory processes that determine cell function, fate and survival. The uncontrolled proliferative capacity of malignant cells generates an unfavorable microenvironment characterized by high metabolic demand, hypoxia, nutrient deprivation and acidosis, which promotes the accumulation of misfolded or unfolded proteins in the ER, leading to ER stress (ERS). Ferroptosis and ERS share common pathways in several diseases, and the two interact to affect cell survival and death. Additionally, cell death pathways are not linear signaling cascades, and different pathways of cell death may be interrelated at multiple levels. Ferroptosis and ERS in ovarian cancer (OC) have attracted increasing research interest; however, both are discussed separately regarding OC. The present review aims to summarize the associations and potential links between ferroptosis and ERS, aiming to provide research references for the development of therapeutic approaches for the management of OC.

Phytochemicals in Parkinson's Disease: a Pathway to Neuroprotection and Personalized Medicine

Parkinson's disease (PD) is a complex neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra. While current treatments primarily manage symptoms, there is increasing interest in alternative approaches, particularly the use of phytochemicals from medicinal plants. These natural compounds have demonstrated promising neuroprotective potential in preclinical studies by targeting key pathological mechanisms such as oxidative stress, neuroinflammation, and protein aggregation. However, the clinical translation of these phytochemicals is limited due to a lack of robust clinical trials evaluating their safety, efficacy, and pharmacokinetics. This review provides a comprehensive overview of the neuroprotective potential of phytochemicals in PD management, examining the mechanisms underlying PD pathogenesis and emphasizing neuroprotection. It explores the historical and current research on medicinal plants like Mucuna pruriens, Curcuma longa, and Ginkgo biloba, and discusses the challenges in clinical translation, including ethical and practical considerations and the integration with conventional therapies. It further underscores the need for future research to elucidate mechanisms of action, optimize drug delivery, and conduct rigorous clinical trials to establish the safety and efficacy of phytochemicals, aiming to shape future neuroprotective strategies and develop more effective, personalized treatments for PD.

A BiP-centric View of Endoplasmic Reticulum Functions and of My Career

After completing my post-doctoral training at the University of Alabama, Birmingham and a brief period on the faculty there, I joined the Department of Tumor Cell Biology at St. Jude Children's Research Hospital in 1987 as an Assistant Member and started my independent research program. For the following 37 years, I led a relatively small basic research group comprised at various times of post-doctoral fellows, graduate students, undergraduate students, and research technicians; many of whom I am still in contact. Last year I closed the lab and transitioned to an emeritus position at St. Jude. I continue to maintain several research collaborations covering areas of research that have long been dear to my heart. My post-doctoral studies on BiP revealed that it controlled immunoglobulin assembly and transport, and as such, played a critical role in the fidelity of the immune response. My lab continued to define BiP's functions in protein folding and subunit assembly, as well as, in degradation of proteins that failed to mature properly using biochemical, cell-based, and biophysical analyses. Several ER localized co-factors that regulate the activity of BiP and allow it to contribute to its multiple ER functions were identified by our group. These include DnaJ family members and nucleotide change factors. Through a variety of collaborative studies, we pursued BiP's functions in maintaining the permeability barrier of the translocon, contributing to ER calcium stores, and regulating the up-stream transducers of the UPR, a stress response that is activated by the accumulation of unfolded proteins in the ER.

Allicin protects against pancreatic damage induced by zearalenone in rats by inhibiting endoplasmic reticulum stress

Zearalenone (ZEL) is a mycotoxin generated by Fusarium fungus. Ingestion of ZEL-contaminated foods by humans or animals can cause major health concerns. This work assessed the protective role of allicin in mitigating pancreatic damage caused by ZEL in rats. The experimental rats were allocated into control, Allicin (45 mg/kg /day), ZEL (20 mg/kg/ day), and Allicin-ZEL groups. The agents were administered orally for six weeks. ZEL enhanced the serum levels of amylase and lipase, oxidative stress parameters, and endoplasmic reticulum (ER) stress biomarkers, along with a marked decrease in the serum level of insulin. The disturbed architecture of pancreatic acini was demonstrated in the form of vacuolation of acini, degenerated acini with pyknotic nuclei, and infiltration around dilated congested blood vessels, in addition to the presence of dilated intralobular ducts with retained secretions. Also, the islet of Langerhans cells showed vacuolation and darkly stained nuclei. Immunohistochemically, a marked rise in the expression of heat shock protein 70 (HSP70) and P53 and a marked decline in insulin expression were demonstrated. Ultrastructurally, the pancreatic acinar cells and islets of Langerhans cells displayed shrunken irregular nuclei with dilated perinuclear cisternae and dilated rER. Interestingly, co-administration of allicin and ZEL greatly mitigated these detrimental effects. In summary, allicin inhibited pancreatic injury induced by ZEL by decreasing oxidative stress, ER stress, and apoptosis.

Using endoplasmic reticulum engineering to improve recombinant protein production in CHO cells

Chinese hamster ovary (CHO) cells are commonly used to produce recombinant therapeutic proteins (RTPs). While recent strategies have significantly improved the expression levels of RTPs in CHO cells, insufficient secretion and endoplasmic reticulum (ER) stress remain major bottlenecks. Therefore, further understanding of the mechanism of the ER stress response, optimization of ER-related folding and degradation pathways, and development of more efficient ER engineering tools are expected to overcome this issue and maximize RTP production. In this review, we summarize the role of ER in recombinant proteins production and explore ER engineering strategies to improve the yield of recombinant proteins in CHO cells. We further discuss ER-related strategies that can improve recombinant protein production, future research directions, and prospective applications.

KDELR3 is transcriptionally activated by FOXM1 and accelerates lung adenocarcinoma growth and metastasis via inhibiting endoplasmic reticulum stress-induced cell apoptosis

Lung cancer is still considered to be the leading cause of cancer-related death worldwide, and lung adenocarcinoma (LUAD) is the most common kind. KDEL Endoplasmic Reticulum Protein Retention Receptor 3 (KDELR3) is a critical regulator of the endoplasmic reticulum (ER) stress and the followed unfolded protein response (UPR) process, which are critical in tumor development. However, the role of KDELR3 in LUAD tumor progression remains poorly understood. In this work, we demonstrated that KDELR3 is significantly upregulated in LUAD tumor tissues and cell lines. Suppression of KDELR3 promoted the phosphorylation level of UPR-related pathways, PERK, and EIF2α in LUAD cell lines. The downregulation of KDELR3 promoted ER stress-induced cell apoptosis, decreased the protein expression of Bcl-2, and increased the protein expression of Bax in LUAD cells. Moreover, the knockdown of KDELR3 inhibits LUAD cell invasion. In vivo animal experiments confirmed that the inhibition of KDELR3 suppresses LUAD tumor growth and metastasis. Mechanistic studies showed that transcription factor FOXM1 may serve as an upstream factor of KDELR3. The upregulation of FOXM1 increased the transcriptional activity of KDELR3. Further results illustrated that FOXM1 directly binds to the promoter of KDELR3, thus upregulating its expression. Finally, rescue experiments demonstrated that FOXM1 inhibition-induced cell apoptosis and invasion could be reversed by KDELR3 overexpression. Overall, our findings indicated that KDELR3 is transcriptionally upregulated by FOXM1 and accelerates tumor growth and lung metastasis in LUAD by inhibiting ER stress-induced cell apoptosis.

Endoplasmic reticulum stress induces trophoblast pyroptosis via regulating CYLD during labor initiation

INTRODUCTION

Preterm birth (PTB) presents significant risks to neonatal health, highlighting a deeper understanding of the mechanisms underlying labor initiation. Maternal-fetal interface inflammation and heightened endoplasmic reticulum stress (ERS) are associated with the onset of PTB, while the molecular mechanism remains unclear. This study investigates ERS levels in placental tissues from term and preterm pregnancies and examines the role of ERS and cylindromatosis (CYLD) in trophoblast pyroptosis to reveal the mechanisms underlying PTB.

METHODS

A total of 60 pregnant women were recruited and categorized into four groups: term labor (TL), term not in labor (TNL), preterm labor (PTL), and preterm not in labor (PTNL). Protein expressions of ERS and pyroptosis-related molecules, including CYLD, were assessed using Western blotting, immunohistochemistry, and immunofluorescence. IL-1β and IL-18 mRNA levels were quantified via real-time PCR. An in vitro inflammatory trophoblast model was established using LPS and ATP co-treatment. ERS modulation was achieved with Thapsigargin (TG) and Tauroursodeoxycholate (TUDCA).

RESULTS

Elevated ERS and pyroptosis-related protein levels were observed in PTB-associated groups and the inflammatory trophoblast model. TG increased CYLD expression and induced cell pyroptosis, while TUDCA mitigated these effects. CYLD silencing reduced trophoblast pyroptosis, whereas overexpression negated TUDCA's inhibitory impact.

DISCUSSION

Our findings indicate that ERS-mediated trophoblast pyroptosis via CYLD under inflammatory conditions sheds light on PTB mechanisms, providing a potential target for modulating labor onset.

The impact of copper-induced oxidative damage on the endoplasmic reticulum quality control system in broiler kidneys

Copper (Cu) is a pervasive element utilized in economic animal production. However, overuse can have toxic effects on animals and threaten public food safety. To gain a deeper understanding of the mechanisms underlying Cu-induced nephrotoxicity, an in-depth analysis was conducted on the effects of Cu on the renal endoplasmic reticulum quality control (ERQC) system. In the course of this experiment, one-day-old chicks were fed diets comprising Cu levels (11, 110, 220 and 330 mg/kg) for 49 days. Our findings indicate that an excess of Cu may result in oxidative stress, which may then induce tissue damage within the kidney. Furthermore, the experimental results indicated that elevated Cu levels may disrupt to the ERQC system in chicken kidneys. The mRNA levels of GRP78, GRP94, ATF4, IRE1, and XBP1, as well as the protein levels of GRP78, GRP94, IRE1, XBP1, and CHOP, were markedly elevated in all treatment groups relative to the control group. Conversely, the mRNA and protein levels of eIF2α and ATF6 exhibited a notable decline with the increase in Cu levels. Similarly, RTN3, ATL1, and ATL2 mRNA levels as well as RTN3 and ATL3 protein levels exhibited a notable elevation in conjunction with an appreciable decline in FAM134B and SEC62 mRNA and protein levels, respectively, as Cu levels increased. Furthermore, bioinformatics analyses indicated a correlation between oxidative damage and ERQC markers. The above results suggest that Cu-induced oxidative damage may injure to chicken kidneys via disturbances in the ERQC system.

Derlin-3 manipulates the endoplasmic reticulum stress and IgG4 secretion of plasma cells in lung adenocarcinoma

Derlin-3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, its potential biomechanisms in the tumor microenvironment (TME) of lung adenocarcinoma (LUAD) remains to be elucidated. In the present study, we found that Derlin-3 was predominantly elevated in LUAD tissues, and could predict worse prognosis of LUAD patients. ScRNA-seq analysis indicated that Derlin-3 was mainly enriched in B lymphocytes in the TME, especially in plasma cells. Moreover, Derlin-3 may be involved in ER stress and IgG4 secretion in plasma cells by targeting Hrd1/p38/PRDM1 pathway. While the aberrant IgG4 production may be an essential driver of the polarization of macrophages towards the M2 phenotype. Additionally, downregulation of Derlin-3 could inhibit plasma cells infiltration and M2 macrophage polarization in vivo. Our results indicated that Derlin-3 could shape TME via ER stress to harness immune function, which might serve as a promising immunotherapeutic target in LUAD.

Effect of microbial diversity and their functions on soil nutrient cycling in the rhizosphere zone of Dahongpao mother tree and cutting Dahongpao

Dahongpao mother tree (Camellia sinensis) is nearly 400 years old and is the symbol of Wuyi rock tea. It is unclear whether the structure and function of the rhizosphere soil microbial community of Dahongpao mother tree (MD) and its cutting Dahongpao (PD) change after planting. In this study, macrogenomics was used to analyze the structure and function of rhizosphere soil microbial communities, as well as to explore their relationship with soil nutrient transformations in MD and PD tea trees. The results showed that pH, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus and available potassium were significantly higher in the rhizosphere soil of MD than in PD by 1.22, 3.24, 5.38, 1.10, 1.52, 4.42 and 1.17 times, respectively. Secondly, soil urease, sucrase, protease, cellulase and catalase activities were also significantly higher in MD than in PD by 1.25-, 2.95-, 1.14-, 1.23-, and 1.30-fold. Macrogenomic analysis showed that rhizosphere soil microbial richness and diversity were higher in MD than in PD. There were eight characteristic microorganisms that significantly differed between MD and PD rhizosphere soils, and the results of functional analysis showed that MD rhizosphere soil microorganisms had higher carbon, nitrogen, and phosphorus biotransformation capacity, were more conducive to the accumulation and release of nutrients in the soil, and were more conducive to the promotion of tea tree growth. The results of PLS-SEM equation analysis showed that characteristic microorganisms positively regulated soil microbial function (1.00**), enzyme activity (0.84*) and nutrient content (0.82*). It can be seen that the abundance of soil characteristic microorganisms in the rhizospehre soil of MD increased significantly compared with that of PD, prompting a significant enhancement of their corresponding functions, which was more conducive to soil improvement, increased soil enzyme activity, enhanced soil nutrient biotransformation, and then increased soil nutrient accumulation and effectiveness, and promoted the growth of tea trees. This study provides an important theoretical basis for microbial regulation of tea tree cuttings management.

Glabridin Alleviates Metabolic Disorders in Diet-Induced Diabetic Mice

Glabridin (GLD) is a flavonoid derived from licorice. This study aims to evaluate GLD's therapeutic potential in ameliorating type 2 diabetes mellitus (T2DM) and elucidate its underlying mechanisms of action. A T2DM model was established using male C57BL/6J mice fed a high-fat, high-glucose diet. GLD was administered via intraperitoneal injection at doses of 10, 20, and 30 mg/kg BW, with MET (200 mg/kg BW) as a positive control. Fasting blood glucose levels, glucose tolerance, insulin tolerance, pyruvate tolerance, and serum parameters were analyzed, along with key markers of glycogen synthesis, gluconeogenesis, lipid metabolism, mitochondrial function, and endoplasmic reticulum (ER) stress. GLD significantly lowered blood glucose levels in the diabetic mice. It suppressed gluconeogenesis by inhibiting PEPCK and G6P, while promoting glycogen synthesis by activating GCK and inhibiting GSK-3β. Additionally, GLD enhanced insulin signaling by increasing IRS1 and IRS2 levels and promoting AKT phosphorylation, thereby improving insulin sensitivity. In lipid metabolism, GLD reduced hepatic steatosis and lipid accumulation by downregulating lipogenesis-related genes (SREBP1c, FAS, ACC1, and SCD1) and upregulating lipolysis-related genes (PPARα and LCAD). In energy metabolism, GLD increased mitochondrial membrane potential, reduced reactive oxygen species levels, and enhanced the expression of genes associated with mitophagy (PINK1 and Parkin) and mitochondrial biogenesis (PGC-1α, SIRT1, and TFAM). Moreover, GLD mitigated ER stress by decreasing GRP78 and CHOP levels, suppressing PERK phosphorylation, and inhibiting key stress response genes. GLD improves insulin sensitivity and exerts antidiabetic effects by ameliorating metabolic disorders, supporting its potential as a therapeutic agent for T2DM.

NOD2 promotes sepsis-induced neuroinflammation by increasing brain endoplasmic reticulum stress mediated by LACC1

BACKGROUND

Although nucleotide-binding oligomerization domain-containing protein 2 (NOD2) has been associated with diverse inflammatory states and some neurological diseases, its role in regulating sepsis-induced neuroinflammation remains unexplored. This study aimed to determine the role of NOD2 in modulating sepsis-induced neuroinflammation and to elucidate its potential mechanisms.

METHODS

mRNA and protein expression levels of NOD2 were measured in the periventricular white matter (PWM) of C57BL/6 mice and the microglia. NOD2-/- mice were generated using the CRISPR/Cas9 technology, and the septic mouse model was established by using cecal ligation puncture (CLP). Microglia were transfected with siRNA specific to NOD2 or laccase domain-containing protein 1 (LACC1) or treated with the endoplasmic reticulum stress (ER stress) inhibitor 4-phenylbutyrate (4-PBA) in vitro under muramyl dipeptide (MDP)-induced neuroinflammation. Immunofluorescence staining, Western blotting, and quantitative reverse transcription polymerase chain reaction were performed to evaluate neuroinflammation and ER stress. The ER structure was observed using transmission electron microscopy.

RESULTS

NOD2 expression level was upregulated in the mouse model of sepsis-induced neuroinflammation. The absence of NOD2 led to a protective effect against neuroinflammation, which was correlated with ER stress both in vitro and in vivo. LACC1 was identified as a notable mediator of ER stress, contributing to the exacerbation of neuroinflammation. Mechanistically, elevated NOD2 expression level promoted neuroinflammation by enhancing ER stress through LACC1. Notably, these effects were partially mitigated by LACC1 downregulation.

CONCLUSIONS

These findings highlight the pivotal role of NOD2 in promoting sepsis-induced neuroinflammation via regulating ER stress mediated by LACC1, and provide a new potential strategy for treating human neuroinflammation.

Protective effect of curcumin against endoplasmic reticulum stress and lipid metabolism disorders in AFB1-intoxicated duck liver

Aflatoxin B1 (AFB1) is a stable and highly toxic toxin that causes multi-organ toxicity with sustained ingestion, most typically in the duck liver. Previous research has shown that AFB1 can bring about endoplasmic reticulum stress (ERS) in animals, and ERS is strongly associated with lipid metabolism. However, the relationship between AFB1-induced duck liver toxicity and ERS and lipid metabolism is currently unclear. Great attention has been paid to the prevention and treatment of AFB1 because of its great harm. Curcumin, a natural polyphenol, is notable for its powerful anti-inflammatory and antioxidant properties. Studies have shown curcumin to be protective against afb1-induced avian multi-organ toxicity. However, the effects of curcumin on the liver of ducks exposed to AFB1 are largely unknown. In the present study, we aimed to investigate whether AFB1 exposure induces ERS and lipid metabolism disorders in duck liver, while exploring the positive role of curcumin in it. One-day-old ducks (n = 80) were randomly divided in four groups: control group, AFB1 group (0.1 mg / kg.bw AFB1), Cur group (400 mg/kg curcumin), and AFB1 + Cur group (0.1 mg/kg.bw AFB1 + 400 mg/kg curcumin), and blood and liver were collected for the study after 21 days of continuous administration. Our research has found that AFB1 exposure significantly increases the levels of liver function indicators ALP, AST, and ALT in ducks' serum (P < 0.05). Duck liver undergoes fatty degeneration under the influence of AFB1. Under the effect of curcumin, AFB1-induced structural damage in duck liver was somewhat controlled. Further experimental results showed that AFB1 treatment significantly increased the expression of glucose-regulated protein 78 (P < 0.001), and activated the endoplasmic reticulum stress pathway. Meanwhile, AFB1 inhibited the LKB1-AMPK signaling pathway and disrupted lipid metabolic homeostasis. And curcumin treatment effectively reversed these changes. Overall, our results suggest that curcumin attenuates AFB1-induced hepatotoxicity in ducks by inhibiting ERS and lipid metabolism disorders.

Deoxynivalenol exposure-related male reproductive toxicity in mammals: Molecular mechanisms, detoxification and future directions

An increasing body of evidence indicates that exposure to widespread, environmental and food contaminants such as mycotoxins may cause endocrine disorders and infertility. Deoxynivalenol (DON), which is a toxic secondary metabolite produced by Fusarium fungi, can lead to multiple harmful effects in humans and animals, such as hepatotoxicity, nephrotoxicity, immunotoxicity, gastrointestinal toxicity, neurotoxicity, genetic toxicity and carcinogenicity. Recently, there has been growing concern about DON-induced male infertility. Exposure to DON and its metabolites can damage the structure and function of male reproductive organs, resulting in impairment of gametogenesis and thus impaired fertility. Potential molecular mechanisms involve oxidative stress, inflammatory response, mitochondrial dysfunction, apoptosis, cell cycle arrest, pyroptosis, and ferroptosis. Moreover, several signaling pathways, including nuclear factor-kappa B, mitogen-activated protein kinase, NLR family pyrin domain containing 3, nuclear factor erythroid 2-related factor 2, AMP-activated protein kinase, mitochondrial apoptotic pathways, and microRNAs are involved in these detrimental biological processes. Research has shown that several antioxidants, small-molecule inhibitors, or proteins (such as lactoferrin) supplementation can potentially offer protective effects by targeting these signaling pathways. This review comprehensively summarizes the harmful effects of DON exposure on male reproductive function in mammals, the underlying molecular mechanisms and emphasizes the potential of several small molecules as protective therapeutics. In the further, the systematic risk assessment when DON at environmental exposure doses to human reproductive health, the in-depth and precise molecular mechanism investigation using emerging technologies, and the development of more effective intervention strategies warrant urgent investigation.

Endoplasmic reticulum stress in non-small cell lung cancer

The Endoplasmic reticulum (ER), an organelle present in various eukaryotic cells, is responsible for protein synthesis, modification, folding, and transport, as well as for the regulation of lipid metabolism and Ca2+ homeostasis. ER stress plays a pivotal role in the pathogenesis and therapeutic response of non-small cell lung cancer (NSCLC), significantly influencing cellular fate decisions through its unique sensing and regulatory mechanisms. This review aims to elucidate the key role of ER stress sensors and to explore how they mediate cell autophagy, apoptosis, and non-apoptotic modes of cell death in the context of drug-treated NSCLC. This investigation lays a solid foundation for optimizing future treatment strategies for NSCLC.

Doxycycline-Induced Apoptosis in Brucella suis S2-Infected HMC3 Cells via Calreticulin Suppression and Activation of the IRE1/Caspase-3 Signaling Pathway

Objective

This study aims to elucidate the apoptotic mechanism induced by doxycycline (Dox) in human microglial clone 3 (HMC3) cells infected with the Brucella suis S2 strain, with the goal of identifying potential therapeutic targets for neurobrucellosis.

Methods

The expression of calreticulin (CALR) at both the protein and mRNA levels was assessed using Western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), respectively, following exposure of HMC3 cells to varying concentrations and treatment durations of Dox. Apoptosis rates were determined via flow cytometry. To investigate the involvement of the inositol-requiring enzyme-1 (IRE1)/Caspase-12/Caspase-3 pathway, CALR protein levels were analyzed through Western blot after a 12-hour treatment with 160 μM Dox. Endoplasmic reticulum (ER) stress and intracellular calcium (Ca²⁺) concentrations were evaluated using fluorescent staining. The same parameters were measured in B. suis S2-infected HMC3 cells following treatment with 160 μM Dox.

Results

Treatment with 160 μM Dox for 12 hours resulted in a reduction in CALR protein levels and the induction of apoptosis in HMC3 cells. The downregulation of CALR activated the IRE1/Caspase-12/Caspase-3 signaling pathway, leading to apoptosis. Similar apoptotic effects were observed in B. suis S2-infected HMC3 cells following Dox treatment.

Conclusion

Dox promotes apoptosis in B. suis S2-infected HMC3 cells by suppressing CALR expression and activating the IRE1/Caspase-12/Caspase-3 signaling pathway. These findings suggest that CALR regulation may serve as a potential therapeutic target for neurobrucellosis.

The role of ubiquitination and deubiquitination in the pathogenesis of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases and is closely associated with metabolic abnormalities. The causes of NAFLD are exceedingly complicated, and it is known that a variety of signaling pathways, endoplasmic reticulum stress, and mitochondrial dysfunction play a role in the pathogenesis of NAFLD. Recent studies have shown that ubiquitination and deubiquitination are involved in the regulation of the NAFLD pathophysiology. Protein ubiquitination is a dynamic and diverse post-translational alteration that affects various cellular biological processes. Numerous disorders, including NAFLD, exhibit imbalances in ubiquitination and deubiquitination. To highlight the significance of this post-translational modification in the pathogenesis of NAFLD and to aid in the development of new therapeutic approaches for the disease, we will discuss the role of enzymes involved in the processes of ubiquitination and deubiquitination, specifically E3 ubiquitin ligases and deubiquitinating enzymes that are important in the regulation of NAFLD.

Traditional Chinese medicine in the prevention of diabetes mellitus and cardiovascular complications: mechanisms and therapeutic approaches

Diabetes mellitus (DM) is a chronic endocrine and metabolic disorder characterized by persistent hyperglycemia that poses serious threats to human health and quality of life. The morbidity, disability, and mortality rates of cardiovascular complications stemming from chronic hyperglycemia are primary factors affecting the lifespan of patients with diabetes. Currently, there is no cure for DM. Standard biomedical treatments mostly control the symptoms using insulin injections or oral hypoglycemic drugs. Although the effect of standard biomedical therapy is remarkable, its long-term use is prone to toxic side effects. Numerous studies have recently found that Traditional Chinese Medicine (TCM) has strong advantages in the prevention and treatment of DM and cardiovascular complications (DACC). The collection, processing, preparation and clinical use of TCM are guided by the theory of TCM and follow the "holistic concept." Multiple components, pathways, and targets form the basis for the use of TCM in treating multiple parts and organs of the body simultaneously. TCM is mainly derived from natural medicines and their processed products and has fewer side effects. TCM is clinically used as compound prescriptions, botanical drugs, and monomers. TCM, either independently or in combination with standard biomedical treatments, has shown unique therapeutic advantages. This review aimed to explore the recently reported mechanisms of action of TCM in the prevention and treatment of DACC. These findings will aid the optimization of the current therapy or formation of a therapeutic schedule for integrated TCM and standard biomedical treatments.

Endoplasmic reticulum stress in gut inflammation: Implications for ulcerative colitis and Crohn's disease

Eukaryotic cells contain the endoplasmic reticulum (ER), a prevalent and intricate membranous structural system. During the development of inflammatory bowel disease (IBD), the stress on the ER and the start of the unfolded protein response are very important. Some chemicals, including 4μ8C, small molecule agonists of X-box binding protein 1, and ISRIB, work on the inositol-requiring enzyme 1, turn on transcription factor 6, and activate protein kinase RNA-like ER kinase pathways. This may help ease the symptoms of IBD. Researchers investigating the gut microbiota have discovered a correlation between ER stress and it. This suggests that changing the gut microbiota could help make new medicines for IBD. This study looks at how ER stress works and how it contributes to the emergence of IBD. It also talks about its possible clinical importance as a therapeutic target and looks into new ways to treat this condition.

Phenylhydrazone-based Endoplasmic Reticulum Proteostasis Regulator Compounds with Enhanced Biological Activity

Pharmacological enhancement of endoplasmic reticulum (ER) proteostasis is an attractive strategy to mitigate pathology linked to etiologically-diverse protein misfolding diseases. However, despite this promise, few compounds have been identified that enhance ER proteostasis through defined mechanisms of action. We previously identified the phenylhydrazone-based compound AA263 as a compound that promotes adaptive ER proteostasis remodeling through mechanisms including activation of the ATF6 signaling arm of the unfolded protein response (UPR). However, the protein target(s) of AA263 and the potential for further development of this class of ER proteostasis regulators had not been previously explored. Here, we employ chemical proteomics to demonstrate that AA263 covalently targets a subset of ER protein disulfide isomerases, revealing a molecular mechanism for the activation of ATF6 afforded by this compound. We then use medicinal chemistry to establish next-generation AA263 analogs showing improved potency and efficacy for ATF6 activation, as compared to the parent compound. Finally, we show that treatment with these AA263 analogs enhances secretory pathway proteostasis to correct the pathologic protein misfolding and trafficking of both a destabilized, disease-associated α1-antitrypsin (A1AT) variant and an epilepsy-associated GABA A receptor variant. These results establish AA263 analogs with enhanced potential for correcting imbalanced ER proteostasis associated with etiologically-diverse protein misfolding disorders.

Amyotrophic Lateral Sclerosis: Focus on Cytoplasmic Trafficking and Proteostasis

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal motor neuron disease characterized by the pathological loss of upper and lower motor neurons. Whereas most ALS cases are caused by a combination of environmental factors and genetic susceptibility, in a relatively small proportion of cases, the disorder results from mutations in genes that are inherited. Defects in several different cellular mechanisms and processes contribute to the selective loss of motor neurons (MNs) in ALS. Prominent among these is the accumulation of aggregates of misfolded proteins or peptides which are toxic to motor neurons. These accumulating aggregates stress the ability of the endoplasmic reticulum (ER) to function normally, cause defects in the transport of proteins between the ER and Golgi, and impair the transport of RNA, proteins, and organelles, such as mitochondria, within axons and dendrites, all of which contribute to the degeneration of MNs. Although dysfunction of a variety of cellular processes combines towards the pathogenesis of ALS, in this review, we focus on recent advances concerning the involvement of defective ER stress, vesicular transport between the ER and Golgi, and axonal transport.

Parkinson's Disease: The Neurodegenerative Enigma Under the "Undercurrent" of Endoplasmic Reticulum Stress

Parkinson's disease (PD), a prevalent neurodegenerative disorder, demonstrates the critical involvement of endoplasmic reticulum stress (ERS) in its pathogenesis. This review comprehensively examines the role and molecular mechanisms of ERS in PD. ERS represents a cellular stress response triggered by imbalances in endoplasmic reticulum (ER) homeostasis, induced by factors such as hypoxia and misfolded protein aggregation, which activate the unfolded protein response (UPR) through the inositol-requiring enzyme 1 (IRE1), protein kinase R-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) pathways. Clinical, animal model, and cellular studies have consistently demonstrated a strong association between PD and ERS. Abnormal expression of ERS-related molecules in PD patients' brains and cerebrospinal fluid (CSF) correlates with disease progression. In animal models (e.g., Drosophila and mice), ERS inhibition alleviates dopaminergic neuronal damage. Cellular experiments reveal that PD-mimicking pathological conditions induce ERS, while interactions between ERS and mitochondrial dysfunction promote neuronal apoptosis. Mechanistically, (1) pathological aggregation of α-synuclein (α-syn) and ERS mutually reinforce dopaminergic neuron damage; (2) leucine-rich repeat kinase 2 (LRRK2) gene mutations induce ERS through thrombospondin-1 (THBS1)/transforming growth factor beta 1 (TGF-β1) interactions; (3) molecules such as Parkin and PTEN-induced kinase 1 (PINK1) regulate ERS in PD. Furthermore, ERS interacts with mitochondrial dysfunction, oxidative stress, and neuroinflammation to exacerbate neuronal injury. Emerging therapeutic strategies show significant potential, including artificial intelligence (AI)-assisted drug design targeting ERS pathways and precision medicine approaches exploring non-pharmacological interventions such as personalized electroacupuncture. Future research should focus on elucidating ERS-related mechanisms and identifying novel therapeutic targets to develop more effective treatments for PD patients, ultimately improving their quality of life.

Endoplasmic Reticulum Stress: Implications in Diseases

Endoplasmic reticulum (ER) is a specialized organelle that plays a significant role in cellular function. The major functions of ER include protein synthesis and transport, folding of proteins, biosynthesis of lipids, calcium (Ca2+) storage, and redox balance. The loss of ER integrity results in the induction of ER stress within the cell due to the accumulation of unfolded, improperly folded proteins or changes in Ca2+ metabolism and redox balance of organelle. This ER stress commences the Unfolded Protein Response (UPR) that serves to counteract the ER stress via three sensors inositol requiring protein-1 (IRE1), protein kinase RNA-like ER kinase (PERK), and activating transcription factor-6 (ATF6) that serve to establish ER homeostasis and alleviates ER stress. Severe ER dysfunction ultimately results in the induction of apoptosis. Increasing shreds of evidence suggest the implication of ER stress in the development and progression of several diseases viz. tuberculosis, malaria, Alzheimer's disease, Parkinson's disease, diabetes, and cancer. Activation of ER stress can be beneficial for treating some diseases while inhibiting the process can be useful in others. A deeper understanding of these pathways can provide key insights in designing novel therapeutics to treat these diseases.

Orchestration of SARS-CoV-2 Nsp4 and host cell ESCRT proteins induces morphological changes of the endoplasmic reticulum

Upon entry into the host cell, the nonstructural proteins 3, 4, and 6 (Nsp3, Nsp 4, and Nsp6) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitate the formation of double-membrane vesicles (DMVs) through extensive rearrangement of the host cell endoplasmic reticulum (ER) to replicate the viral genome and translate viral proteins. To dissect the functional roles of each Nsp and the molecular mechanisms underlying the ER changes, we exploited both yeast Saccharomyces cerevisiae and human cell experimental systems. Our results demonstrate that Nsp4 alone is sufficient to induce ER structural changes. Nsp4 expression led to robust activation of both the unfolded protein response (UPR) and the ER surveillance (ERSU) cell cycle checkpoint, resulting in cortical ER inheritance block and septin ring mislocalization. Interestingly, these ER morphological changes occurred independently of the canonical UPR and ERSU components but were mediated by the endosomal sorting complex for transport (ESCRT) proteins Vps4 and Vps24 in yeast. Similarly, ER structural changes occurred in human cells upon Nsp4 expression, providing a basis for a minimal experimental system for testing the involvement of human ESCRT proteins and ultimately advancing our understanding of DMV formation.

Endoplasmic reticulum stress and unfolded protein response: Roles in skeletal muscle atrophy

Skeletal muscle atrophy is commonly present in various pathological states, posing a huge burden on society and patients. Increased protein hydrolysis, decreased protein synthesis, inflammatory response, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) are all important molecular mechanisms involved in the occurrence and development of skeletal muscle atrophy. The potential mechanisms of ERS and UPR in skeletal muscle atrophy are extremely complex and have not yet been fully elucidated. This article elucidates the molecular mechanisms of ERS and UPR, and discusses their effects on different types of muscle atrophy (muscle atrophy caused by disuse, cachexia, chronic kidney disease (CKD), diabetes mellitus (DM), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal and bulbar muscular atrophy (SBMA), aging, sarcopenia, obesity, and starvation), and explores the preventive and therapeutic strategies targeting ERS and UPR in skeletal muscle atrophy, including inhibitor therapy and drug therapy. This review aims to emphasize the importance of endoplasmic reticulum (ER) in maintaining skeletal muscle homeostasis, which helps us further understand the molecular mechanisms of skeletal muscle atrophy and provides new ideas and insights for the development of effective therapeutic drugs and preventive measures for skeletal muscle atrophy.

The immunosuppressive role of MDSCs in HCC: mechanisms and therapeutic opportunities

Hepatocellular carcinoma (HCC) is a prevalent malignancy with a significant global burden. Despite substantial advancements in HCC treatment in recent years, therapeutic efficacy remains constrained by immune evasion mechanisms within the tumor microenvironment (TME). Myeloid-derived suppressor cells (MDSCs), as critical immunosuppressive elements of the TME, have garnered increasing attention for their role in tumor progression. Recent studies emphasize their central involvement in promoting immune evasion, tolerance, and immunosuppression in HCC. This review examines the contributions of MDSCs to HCC pathogenesis, elucidates their underlying mechanisms, and discusses ongoing clinical trials, emphasizing their potential as therapeutic targets for improving clinical outcomes.

TIGAR Suppresses ER Stress-Induced Neuronal Injury through Targeting ATF4 Signaling in Cerebral Ischemia/Reperfusion

Endoplasmic reticulum (ER) stress is crucial in cerebral ischemia/reperfusion injury by triggering cellular apoptosis and exacerbating neuronal damage. This study elucidates the dynamics of TP53-induced glycolysis and apoptosis regulator (TIGAR) translocation and its role in regulating neural fate during cerebral ischemia-induced ER stress, specifically in male mice. We found enhanced nuclear localization of TIGAR in neurons after transient middle cerebral artery occlusion/reperfusion (tMCAO/R) in male mice, as well as oxygen glucose deprivation/reperfusion (OGD/R) and treatment with ER stress inducer (tunicamycin and thapsigargin) in neuronal cells. Conditional neuronal knockdown of Tigar aggravated the injury following ischemia-reperfusion, whereas overexpression of Tigar attenuated cerebral ischemic injury and ameliorated intraneuronal ER stress. Additionally, TIGAR overexpression reduced the elevation of ATF4 target genes and attenuated ER stress-induced cell death. Notably, TIGAR colocalized and interacted with ATF4 in the nucleus, inhibiting its downstream proapoptotic gene transcription, consequently protecting against ischemic injury. In vitro and in vivo experiments revealed that ATF4 overexpression reversed the protective effects of TIGAR against cerebral ischemic injury. Intriguingly, our study identified the Q141/K145 residues of TIGAR, crucial for its nuclear translocation and interaction with ATF4, highlighting a novel aspect of TIGAR's function distinct from its known phosphatase activity or mitochondrial localization domains. These findings reveal a novel neuroprotective mechanism of TIGAR in regulating ER stress through ATF4-mediated signaling pathways. These insights may guide targeted therapeutic strategies to protect neuronal function and alleviate the deleterious effects of cerebral ischemic injury.

Brucella suis S2 strain inhibits IRE1/caspase-12/caspase-3 pathway-mediated apoptosis of microglia HMC3 by affecting the ubiquitination of CALR

Neurobrucellosis represents a severe complication of brucellosis, posing a considerable risk to human health and quality of life. This condition arises from an increased susceptibility to chronic Brucella infection, a significant clinical challenge. One key factor contributing to chronic neurobrucellosis is the regulation of microglial apoptosis by Brucella; however, the exact molecular mechanisms remain largely unresolved. In this study, human microglial clone 3 (HMC3) cells were infected with Brucella suis vaccine strain S2 (B. suis S2) at varying multiplicity of infection (MOI) and durations to assess its effects on the IRE1/caspase-12/caspase-3 signaling pathway. Following the suppression of this pathway by B. suis S2, calreticulin (CALR) was identified through ubiquitin-modified proteomics (data accessible via ProteomeXchange, identifier PXD056006). To further investigate, CALR-overexpression and knockdown HMC3 cell lines were infected with B. suis S2 to elucidate the mechanism by which B. suis S2 inhibits apoptosis in HMC3 cells. In conclusion, our findings demonstrate that B. suis S2 suppresses HMC3 cell apoptosis via the IRE1/caspase-12/caspase-3 pathway by modulating CALR ubiquitination. This study provides a theoretical basis for exploring the mechanisms of neurobrucellosis and offers insights into its clinical treatment.IMPORTANCENeurobrucellosis is a severe complication impacting the central nervous system (CNS) due to neurological deficits caused by Brucella, with primary clinical features including meningitis, encephalitis, brain abscesses, and demyelinating lesions. These nonspecific symptoms often lead to misdiagnosis or delayed diagnosis, increasing the risk of recurrent or chronic neurobrucellosis infections. Consequently, persistent infection and relapse are critical challenges in the clinical management of neurobrucellosis, which are closely linked to Brucella's survival and replication within microglia. Interestingly, Brucella may inhibit microglia apoptosis by mitigating endoplasmic reticulum (ER) stress, though the precise molecular mechanisms remain largely unexplored. Thus, this study will elucidate the specific mechanisms by which Brucella suppresses microglial apoptosis and provide deeper insights into the molecular pathogenesis and clinical treatment of neurobrucellosis.

Ltc1 localization by EMC regulates cell membrane fluidity to facilitate membrane protein biogenesis

The EMC complex, a highly conserved transmembrane chaperone in the endoplasmic reticulum (ER), has been associated in humans with sterol homeostasis and a myriad of different cellular activities, rendering the mechanism of EMC functionality enigmatic. Using fission yeast, we demonstrate that the EMC complex facilitates the biogenesis of the sterol transfer protein Lam6/Ltc1 at ER-plasma membrane and ER-mitochondria contact sites. Cells that lose EMC function sequester unfolded Lam6/Ltc1 and other proteins at the mitochondrial matrix, leading to surplus ergosterol, cold-sensitive growth, and mitochondrial dysfunctions. Remarkably, inhibition of ergosterol biosynthesis, but also fluidization of cell membranes to counteract their rigidizing effects, reduce the ER-unfolded protein response and rescue growth and mitochondrial defects in EMC-deficient cells. These results suggest that EMC-assisted biogenesis of Lam6/Ltc1 may provide, through ergosterol homeostasis, optimal membrane fluidity to facilitate biogenesis of other ER-membrane proteins.

EM-12, a natural sesquiterpene lactone extracted from Elephantopus mollis, promotes cancer cell apoptosis by activating ER stress

The Elephantopus mollis H.B.K. contains various sesquiterpene lactones that have shown anti-proliferative and proapoptotic effects in various cancers, although the underlying mechanisms are partially understood. Inducing of excessive ER stress is a potential cancer therapeutic strategy. However, ER stress activator remain limited in current clinical applications. In this study, we identified that EM-12, an uncovered sesquiterpene lactone isolated from Elephantopus mollis H.B.K., as a BiP ATPase activity inhibitor through BiP ATPase activity assay in vitro. This molecule also exhibits significantly greater cytotoxicity in numerous ovarian cancer cell lines, including paclitaxel-resistance ovarian cancer cell line, compared to transformed ovarian epithelial cell lines. In addition, EM-12 exerts broad-spectrum cytotoxicity against various human cancer cell lines, including liver, nasopharyngeal, and breast cancer cell lines. Mechanically, EM-12 promotes ER stress and ER-stress-related apoptosis to against cancer cells through inhibiting BiP ATPase activity.

PCSK1N as a Tumor Size Marker and an ER Stress Response Protein in Corticotroph Pituitary Adenomas

CONTEXT

Silent corticotroph adenoma (SCA) exhibits more tumor aggressiveness features than functioning adenomas (FCAs).

OBJECTIVE

We aimed to investigate proprotein convertase subtilisin/kexin type 1 inhibitor (PCSK1N) expression in CA and examine if endoplasmic reticulum (ER) stress-induced responses affect cell survival in a corticotroph tumor cell model.

METHODS

Clinical and imaging characteristics were recorded in 33 patients with FCA (20 women, 11 macroadenomas) and 18 SCAs (8 women, all macroadenomas). Gene expression of pro-opiomelanocortin (POMC), T-box transcription factor 19(TBX19)/TPIT, proprotein convertase subtilisin/kexin type 1 (PCSK1)/PC1/3, and its inhibitor PCSK1N, was measured by reverse transcription-quantitative polymerase chain reaction in adenoma tissue. Mouse pituitary corticotroph tumor (AtT-20) cells were treated with tanespimycin (17-AAG), an HSP90 chaperone inhibitor, to induce ER stress, followed by gene and protein analyses.

RESULTS

POMC, TPIT, and PCSK1 expression were higher, whereas PCSK1N was lower in FCA compared to SCA. PCSK1N correlated with POMC (rs = -0.514; P < .001), TPIT (rs = -0.386; P = .005), PCSK1 (rs = -0.3691; P = .008), and tumor largest diameter (rs = 0.645; P < .001), in all CA. Induction of ER stress by 17-AAG in AtT-20 cells led to a decrease of Pomc and an increase of Pcsk1n gene expression at 24 hours. Moreover, a downregulation of cell cycle, apoptosis, and senescence pathways, and alterations in cell adhesion and cytoskeleton, were observed at the protein level.

CONCLUSION

PCSK1N is higher in SCA compared with FCA, and associated with corticotroph cell markers and tumor size. PCSK1N is likely to be part of the adaptive response to ER stress, potentially conferring a survival advantage to the corticotroph tumor cell in conjunction with other proteins.

Ameliorative Effect of Itaconic Acid/IRG1 Against Endoplasmic Reticulum Stress-Induced Necroptosis in Granulosa Cells via PERK-ATF4-AChE Pathway in Bovine

The necroptosis of granulosa cells has been proven to be one of the important triggers of follicular atresia, which is an important cause of reduced reproductive capacity in cows. The rapid growth of granulosa cells is accompanied by endoplasmic reticulum stress (ERS), leading to granulosa cell death. However, the link between ERS and necroptosis, as well as its mechanism in bovine granulosa cells is still unclear. Itaconic acid is an endogenous anti-inflammatory and antioxidant small-molecule compound that can alleviate ERS. Therefore, the aim of the current study is to evaluate the effect of ERS on necroptosis and investigate the ameliorative effect of itaconic acid against ERS-induced necroptosis in granulosa cells. Bovine granulosa cells were treated with tunicamycin (Tm) to induce ERS. After the addition of the necroptosis inhibitor Nec-1 and the detection of the necroptosis inducer acetylcholinesterase (AChE), flow cytometry, transmission electron microscopy, and mass spectrometry were used to analyze the expression of itaconic acid and IRG1 in the granulosa cells. In addition, the role of the PERK pathway downstream of ERS in ERS-induced necroptosis was also investigated. We report here that ERS can induce necroptosis in granulosa cells. Itaconic acid supplementation significantly attenuates the effect of ERS-induced damage. In summary, this research provides a scientific basis and a drug reference for treating follicular atresia and improving bovine reproductive capacity.

Mitochondria-associated endoplasmic reticulum membranes and myocardial ischemia: from molecular mechanisms to therapeutic strategies

Myocardial ischemia has the highest disease burden among all cardiovascular diseases making it a significant challenge to the global public health. It can result in myocardial cell damage and death due to impaired mitochondrial and endoplasmic reticulum (ER) functions. These two organelles are important regulators of cell death. In recent years, research has shifted from isolated studies of individual organelles to a more integrative approach, with a particular focus on their membrane contact sites-Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs). These dynamic microdomains play a crucial role in regulating material exchange and signal transduction between the endoplasmic reticulum and mitochondria. This review comprehensively describes the intricate structure of MAMs and their multifaceted roles in cellular pathophysiological processes. Particular focus was directed at the far-reaching effects of MAMs in regulating key pathological events including calcium homeostasis, mitochondrial dysfunction, ER stress, oxidative stress, and autophagy in ischemic heart disease (IHD). The potential treatment targets and regulatory mechanisms of MAMs were discussed and summarized, providing novel research directions and treatment approaches for improving myocardial ischemia-related diseases.

Dysregulation of N-glycosylation by Rpn1 knockout in spermatocytes induces male infertility via endoplasmic reticulum stress in mice

N-glycosylation protein modification plays a crucial regulatory role in numerous biological processes, although their contribution to male reproduction in mammals remains largely undefined. Here, we found that Ribophorin I (RPN1), a subunit of oligosaccharyltransferase complex, is indispensable for spermatogenesis in male germ cells. Germ cell-specific Rpn1 knockout results in significant inhibition of the progression of meiosis, consequently disrupting homologous chromosome pairing, meiotic recombination, and DNA double strand breaks repair during meiosis. N-glycoproteomic profiling revealed that glycosylation levels are reduced in endoplasmic reticulum-associated proteins, while functional analyses showed that Rpn1 deficiency could inhibit endoplasmic reticulum function and trigger endoplasmic reticulum stress during meiosis and increasing apoptosis levels in mice. These findings highlight the essential physiological functions of N-glycosylation modification in male spermatogenesis and expand our understanding of its role in male fertility.

Comprehensive Review of Osteogenesis Imperfecta: Current Treatments and Future Innovations

Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by bone fragility due to reduced bone quality, often accompanied by low bone mass, recurrent fractures, hearing loss, skeletal abnormalities, and short stature. Pathogenic variants in over 20 genes lead to clinical and genetic variability in OI, resulting in diverse symptoms and severity. Current management involves a multidisciplinary approach, including antiresorptive medications, physiotherapy, occupational therapy, and orthopedic surgery, which provide symptomatic relief but no cure. Advancements in gene therapy technologies and stem cell therapies offer promising prospects for long-lasting or permanent solutions. This review provides a comprehensive overview of OI's classification, pathogenesis, and current treatment options. It also explores emerging biotechnologies for stem cells and gene-targeted therapies in OI. The potential of these innovative therapies and their clinical implementation challenges are evaluated, focusing on their imminent success in treating bone disorders.

Advances in Studying the Pathologic Mechanisms and Treatment Strategies of Transthyretin Amyloidosis

ABSTRACT

Transthyretin amyloidosis (ATTR) is characterized by the deposition of unstable transthyretin protein (TTR) in the heart or peripheral nerves. Therapeutic strategies for ATTR include inhibition of the secretion of abnormal TTR by the liver, reducing the concentration of aberrant TTR in the circulation, and eliminating amyloid deposits of TTR in tissues. This article delves into the pathogenesis of TTR secretion from the liver into the bloodstream, its deposition in tissues, and the subsequent development of ATTR. In addition, we delineated the advancements in treatment strategies and discussed future research directions to provide novel insights for the identification of diagnostic and preventive targets.

Atp24δ8, a p24 family member, regulates the unfolded protein response and ER stress tolerance in Arabidopsis

ER stress activates the unfolded protein response (UPR), a critical mechanism for maintaining cellular homeostasis in plants. The p24 protein family is known to be involved in protein trafficking between the endoplasmic reticulum (ER) and the Golgi apparatus, but its role in ER stress remains unclear in plants. In this study, we found that Atp24δ8(delta8), a member of the δ-2 subclass of the p24 family, is significantly upregulated in response to tunicamycin-induced ER stress. Subcellular localization confirmed that Atp24δ8 resides in the ER, and CRISPR-Cas9 loss-of-function mutants displayed increased sensitivity to ER stress. Further analysis showed that Atp24δ8 regulates key UPR genes, highlighting its role in promoting ER stress tolerance. These findings provide new insights into the molecular mechanisms that plants use to cope with ER stress, potentially contributing to the development of stress-tolerant crops.

CHOP aggravates hepatocyte apoptosis upon endoplasmic reticulum stress by downregulating autophagy

Endoplasmic reticulum (ER) stress-induced apoptosis plays a crucial role in various liver diseases. Hepatocytes respond to ER stress by activating the unfolded protein response and autophagy, which is essential for maintaining ER homeostasis. However, failure to restore ER balance via autophagy contributes to apoptosis. In this study, we aimed to explore the role of C/EBP homologous protein (CHOP) in regulating ER stress-induced apoptosis in rat hepatocytes. We found that CHOP downregulates autophagy, aggravating apoptosis. Our results revealed that inhibition of CHOP expression enhanced autophagy and reduced DTT-induced apoptosis in BRL-3A cells, whereas CHOP overexpression worsened apoptosis. Chromatin immunoprecipitation assays revealed that CHOP negatively regulates autophagy-related genes, such as ATG12, ATG5, and LC3. These findings suggest that CHOP modulation plays a crucial role in ER stress-induced hepatocyte apoptosis by regulating autophagy.

Thonningianin A ameliorates acetaminophen-induced liver injury by activating GPX4 and modulating endoplasmic reticulum stress

Introduction

Acetaminophen (APAP) is widely used as an analgesic and antipyretic. However overdose APAP can lead to acute liver injury (ALI), representing a significant challenge for public health due to limited treatment options. Current research highlights the need for safer and more effective therapies for APAP-induced liver injury, especially those that target oxidative and endoplasmic reticulum (ER) stress pathways. This study investigates the protective effects of Thonningianin A (TA), a flavonoid compound derived from Penthorum chinense Pursh, in mitigating APAP-induced hepatotoxicity.

Methods

The experimental design involved administering TA at doses of 20 mg/kg and 40 mg/kg to C57BL/6 mice prior to inducing hepatotoxicity with APAP.

Results and discussion

TA treatment significantly lowered plasma ALT and AST levels, inhibited the production of inflammatory cytokines, and reduced oxidative stress markers in liver tissues. Furthermore, TA modulated apoptosis-related proteins by increasing BCL-2 expression while decreasing CHOP and BAX levels. It alleviated endoplasmic reticulum (ER) stress by downregulating GRP78, p-PERK, and ATF4. Notably, liver-specific GPX4 knockdown, achieved through AAV-8-mediated shRNA delivery, abolished the hepatoprotective effects of TA, underscoring GPX4's essential role in mediating TA-induced hepatoprotection. These findings suggest TA as a promising therapeutic agent in managing APAP-induced liver injury, with its unique action on both oxidative and ER stress pathways contributing to its hepatoprotective efficacy.

ERS regulates endometrial epithelial cell autophagy through XBP1s-mediated activation of the PI3K/AKT pathway

Autophagy is a fundamental cellular activity involved in the renewal of cellular components, occurring primarily in cells subjected to physiological remodeling or pathological stimuli. The occurrence of autophagy is closely related to the endoplasmic reticulum (ER), and ER stress (ERS) occurs when ER homeostasis is disrupted. The current study aimed to analyze the molecular mechanisms underlying the effects of ERS on autophagy in goat endometrial epithelial cells (gEECs). We found that rapamycin (an autophagy inducer) induced autophagy and ERS in a time-dependent manner in gEECs which was accompanied by significantly increased expression of the autophagy-related genes ATG5, the LC3II/LC3I and ERS-related genes GRP78, IRE1, ATF6, and XBP1s. PI3K and AKT protein phosphorylation was significantly reduced during gEECs autophagy. Interestingly, TG (ERS activator) significantly inhibited the expression of ATG5 and the LC3II/LC3I and significantly promoted expression of SQSTM1, whereas the ERS inhibitor 4-PBA showed the opposite results. Surprisingly, XBP1s knockdown inhibited the effects of TG. Furthermore, XBP1s overexpression significantly inhibited autophagy whereas XBP1s knockdown increased ATG5 expression and the LC3II/LC3I and decreased SQSTM1 expression in gEECs. Specifically, XBP1s overexpression significantly promoted PI3K and AKT protein phosphorylation while treatment with LY294002 (PI3K/AKT pathway inhibitor) significantly reversed the effect. Similarly, PI3K/AKT pathway activation was significantly inhibited following XBP1s knockdown whereas treatment with SC79 (PI3K/AKT pathway activator) showed the opposite results. Taken together, our data suggest that interactions between ERS and autophagy exist in gEECs. XBP1s, the key effector of ERS, inhibits autophagy in gEECs by promoting the PI3K/AKT pathway in gEECs. These results may contribute to the treatment and prevention of uterine diseases.

The emerging roles of the endoplasmic reticulum in mechanosensing and mechanotransduction

Cells are continuously subjected to physical and chemical cues from the extracellular environment, and sense and respond to mechanical cues via mechanosensation and mechanotransduction. Although the role of the cytoskeleton in these processes is well known, the contribution of intracellular membranes has been long neglected. Recently, it has become evident that various organelles play active roles in both mechanosensing and mechanotransduction. In this Review, we focus on mechanosensitive roles of the endoplasmic reticulum (ER), the functions of which are crucial for maintaining cell homeostasis. We discuss the effects of mechanical stimuli on interactions between the ER, the cytoskeleton and other organelles; the role of the ER in intracellular Ca2+ signalling via mechanosensitive channels; and how the unfolded protein response and lipid homeostasis contribute to mechanosensing. The expansive structure of the ER positions it as a key intracellular communication hub, and we additionally explore how this may be leveraged to transduce mechanical signals around the cell. By synthesising current knowledge, we aim to shed light on the emerging roles of the ER in cellular mechanosensing and mechanotransduction.

In Vitro Inhibition of Endoplasmic Reticulum Stress: A Promising Therapeutic Strategy for Patients with Crohn's Disease

BACKGROUND

Crohn's disease (CD) is an inflammatory bowel disease marked by an abnormal immune response and excessive pro-inflammatory cytokines, leading to impaired protein processing and endoplasmic reticulum (ER) stress. This stress, caused by the accumulation of misfolded proteins, triggers the unfolded protein response (UPR) through IRE1/Xbp-1, PERK/eIF2α, and ATF6 pathways, which are linked to intestinal inflammation. This study aimed to investigate ER stress in CD patients' intestinal mucosa and evaluate phenylbutyrate (PBA) as an ER stress inhibitor.

METHODS

Colon biopsies from CD patients and controls were cultured under five conditions, including 4-PBA treatments. Real-time PCR, cytokine level, and immunohistochemistry were performed.

RESULTS

Immunohistochemistry revealed that ER stress was activated in CD patients' intestinal epithelial cells and lamina propria cells. PERK/eIF2α, but not IRE1/Xbp-1 or ATF6, was upregulated in CD patients compared to controls. UPR-related genes (STC2, CALR, HSPA5, HSP90B1) were also elevated in CD patients. PBA treatment significantly reduced ER stress and UPR markers while decreasing apoptotic markers like DDIT3. Pro-inflammatory cytokines, such as IL-1β, IL-6, IL-17, TNF- α, and sCD40L, were significantly reduced after PBA treatment.

CONCLUSION

ER stress and UPR pathways are activated in CD colonic mucosa, and PBA reduces these markers, suggesting potential therapeutic benefits for CD-related inflammation.

Proteomic Analysis of Plants with Binding Immunoglobulin Protein Overexpression Reveals Mechanisms Related to Defense Against Moniliophthora perniciosa

Moniliophthora perniciosa is one of the main pathogens affecting cocoa, and controlling it generally involves planting resistant genotypes followed by phytosanitary pruning. The identification of plant genes related to defense mechanisms is crucial to unravel the molecular basis of plant-pathogen interactions. Among the candidate genes, BiP stands out as a molecular chaperone located in the endoplasmic reticulum that facilitates protein folding and is induced under stress conditions, such as pathogen attacks. In this study, the SoyBiPD gene was expressed in Solanum lycopersicum plants and the plants were challenged with M. perniciosa. The control plants exhibited severe symptoms of witches' broom disease, whereas the transgenic lines showed no or mild symptoms. Gel-free proteomics revealed significant changes in the protein profile associated with BiP overexpression. Inoculated transgenic plants had a higher abundance of resistance-related proteins, such as PR2, PR3, and PR10, along with increased activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase, and fungal cell wall-degrading enzymes (glucanases). Additionally, transgenic plants accumulated less H2O2, indicating more efficient control of reactive oxygen species (ROS). The interaction network analysis highlighted the activation of defense-associated signaling and metabolic pathways, conferring a state of defensive readiness even in the absence of pathogens. These results demonstrate that BiP overexpression increases the abundance of defense proteins, enhances antioxidant capacity, and confers greater tolerance to biotic stress. This study demonstrates the biotechnological potential of the BiP gene for genetic engineering crops with increased resistance to economically important diseases, such as witches' broom in cocoa.

Ubiquitin and Ubiquitin-Like Modifications in Organelle Stress Signaling: Ub, Ub, Ub, Ub, Stayin' Alive, Stayin' Alive

Due to various intracellular and external cues, cellular organelles are frequently stressed in both physiological and pathological conditions. Sensing these stresses initiates various signaling pathways which may lead to adaptation of the stressed cells or trigger its their death. At the unicellular level, this stress signaling involves a crosstalk between different organelles. At the multicellular level, such pathways can contribute to indicate the presence of a stressed cell to its neighboring cells. Here, we highlight the crucial and diverse roles played by Ubiquitin and Ubiquitin-like modification in organelle stress signaling.