ER stress-induced cell death mechanisms

Perinuclear organelle trauma at the nexus of cardiomyopathy pathogenesis arising from loss of function LMNA mutation

Over the past 25 years, nuclear envelope (NE) perturbations have been reported in various experimental models with mutations in the LMNA gene. Although the hypothesis that NE perturbations from LMNA mutations are a fundamental feature of striated muscle damage has garnered wide acceptance, the molecular sequalae provoked by the NE damage and how they underlie disease pathogenesis such as cardiomyopathy (LMNA cardiomyopathy) remain poorly understood. We recently shed light on one such consequence, by employing a cardiomyocyte-specific Lmna deletion in vivo in the adult heart. We observed extensive NE perturbations prior to cardiac function deterioration with collateral damage in the perinuclear space. The Golgi is particularly affected, leading to cytoprotective stress responses that are likely disrupted by the progressive deterioration of the Golgi itself. In this review, we discuss the etiology of LMNA cardiomyopathy with perinuclear 'organelle trauma' as the nexus between NE damage and disease pathogenesis.

Altered lung inflammation and expression of endoplasmic reticulum stress markers in male mice aged-asthma model

Although there is a strong correlation between aging and asthma pathophysiology, the underlying mechanism has not been fully elucidated. The endoplasmic reticulum (ER) has been demonstrated to be a crucial intracellular organelle involved in the pathogenesis of numerous diseases. The aim of the current study was to investigate ER stress markers in the lung tissue of aged ovalbumin (OVA)-sensitized mice. Male BALB/C mice were randomly divided into the following four groups (10 in each): 1) control, 2) OVA-sensitized (OVA), 3) D-galactose-induced aging (D-gal), and 4) OVA-sensitized associated with D-galactose-induced aging (OVA+D-gal). Total WBCs and differential cells were counted using the bronchoalveolar lavage (BAL) fluid. Lung tissue was analyzed for ER stress markers (ATF4, ATF6, GRP78, CHOP, and XBP1) through Real Time-PCR technique as well as histopathological assessment. The data indicated a significant increase in both total WBCs and differential cells within the OVA, D-gal, and OVA+D-gal groups when compared to the control group, particularly evident in the OVA+D-gal group. Also, the results showed that the increased expression of ER stress markers (ATF4, ATF6, GRP78, CHOP, and XBP1) was significantly higher in the OVA, D-gal, and OVA+D-gal groups than in the control group. Interestingly, the increased expression of CHOP, ATF4, and XBP1 was observed in the OVA+D-gal group more than in other groups. In aged OVA-sensitized mice, the findings revealed a maladaptive ER stress response in their lung tissue, characterized by elevated levels of CHOP, ATF4, and XBP1 expression.

Excessive expression of progranulin leads to neurotoxicity rather than neuroprotection

Frontotemporal dementia (FTD) is an early onset form of dementia characterized by frontotemporal lobar atrophy accompanied by behavioral, personality, language, and motor deficits. Heterozygous mutations in GRN gene encoding progranulin (PGRN) are the genetic causes of FTD. Since PGRN is a neurotrophic and anti-inflammatory factor, most FTD-related PGRN mutations are thought to cause FTD due to haploinsufficiency. Therefore, therapies that increase PGRN levels by the administration of recombinant PGRN or viral vectors are attracting attention as an approach to the treatment of FTD. However, the mechanisms underlying the neuroprotective effects of PGRN remain unclear. To investigate the neuroprotective mechanisms of PGRN in vivo, we generated human PGRN transgenic (Tg) mice using the CAG promoter. Unexpectedly, mice overexpressing wild-type human PGRN showed a shortened lifespan and cerebellar dysfunction, including the loss of Purkinje cells. Furthermore, PGRN Tg mice developed cognitive impairment, gliosis, and lysosomal abnormalities. FTD-causative R432C-PGRN mutant Tg mice also showed FTD-like phenotypes, such as neuronal loss, gliosis, and behavioral deficits. In cultured cells, overexpression of PGRN induced endoplasmic reticulum (ER) stress and apoptotic cell death, suggesting that continuous increases in PGRN expression through viral vectors or genetic manipulation are neurotoxic and that PGRN-replacement therapy may be required to maintain optimal PGRN levels for each neuron type and brain region.

Independent and Combined Effects of Particulate Matter and Sleep Deprivation on Human Skin Barrier

BACKGROUND

The exposome encompasses all factors people encounter through life, with the skin constantly exposed. While particulate matter (PM) and sleep deprivation are known to contribute to barrier dysfunction, their combined effects remain unclear.

OBJECTIVE

To evaluate the independent and combined effects of PM exposure and short-term sleep deprivation on skin barrier function.

METHODS

Forty healthy Korean women (aged 24-58 years) were enrolled in this study. Forearms were divided into 4 sites: control, PM exposure, sleep deprivation, and PM plus sleep deprivation. Parameters such as trans-epidermal water loss (TEWL), hydration, elasticity, roughness, and redness were measured at baseline and post-exposure. RNA sequencing and reverse transcription-polymerase chain reaction were conducted on tape-stripped skin samples.

RESULTS

PM exposure significantly increased TEWL (+25.59%, p<0.01), roughness (+21.9%, p<0.01), and redness (+13.7%, p<0.0001) while reducing elasticity (-3.98%, p<0.01). Sleep deprivation modestly reduced elasticity (-1.39%, p<0.05) without affecting other parameters. Combined PM and sleep deprivation did not further exacerbate barrier dysfunction compared to PM alone. RNA sequencing revealed reduced FLG and LORICRIN expression and upregulated endoplasmic reticulum (ER) stress markers (HSP90B1, CANX) in both PM and sleep deprivation conditions.

CONCLUSION

PM exposure impaired skin barrier function, while short-term sleep deprivation alone did not significantly affect the barrier, either independently or in combination with PM. However, it was observed that the sleep deprivation-only, while not directly causing barrier damage, induced changes in ER stress-related gene expression in tape-stripped skin samples, like the PM exposure-only. This suggests that such signaling pathways could potentially exacerbate skin barrier deterioration.

Folate receptor-targeted pH-sensitive liposomes loaded with TGX-221 against prostate cancer by inhibiting PI3K/110β signaling

Prostate cancer (PCa) is the most common cancer in men and the leading cause of cancer death worldwide. Overactivation of PI3K signaling has been reported to be associated with PCa. TGX221 is an effective specific inhibitor of PI3K, but its clinical application is greatly limited due to its poor solubility. Herein, by using folic acid-PEG-cholesterol semi-succinate (FA-PEG-CHEMS) as the targeting component, we developed a folate receptor-targeted pH-sensitive liposomal delivery system loaded with TGX221 (FA-Lip-TGX221) that could realize effective delivery and controlled release of drugs in the tumor. The prepared liposomes exhibited a uniform particle size and high stability. In addition, FA-Lip-TGX221 could be effectively internalized by PC-3 cells due to its ability to target folate receptors, thereby accumulating in tumor tissues. Meanwhile, in vitro and in vivo experiments suggested that FA-Lip-TGX221 could activate the PERK-ATF4-CHOP signaling pathway by inhibiting PI3K/110β signaling in PCa, thus significantly promoting endoplasmic reticulum (ER) stress-mediated cancer cell death. In conclusion, FA-Lip-TGX221 is a promising nano-delivery vehicle for the treatment of PCa, and also provide valuable references for all tumors overexpressing folate receptors.

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.

Unveiling the HSP90 inhibitor mediated effects on endoplasmic reticulum stress and redox signaling:from a cancer inhibitor to retinal degeneration catalyst

Retinal degeneration (RD) is a class of polygenic blind eye disease characterized by photoreceptors loss and dysfunction of retinal pigment epithelium. Thus far, there is no effective treatment to save the declining vision in RD patients. Animal models are highly precious tools for studying the pathological mechanisms of RD, and for screening potential therapeutics. AUY922 is a heat shock protein 90 inhibitor that exhibits potent anti-cancer effects. However, it causes adverse ocular reactions such as reduced visual acuity and night blindness. This study intends to explore the pathological mechanism underlying the AUY922 induced RD. In vitro study, AUY922 induced cytotoxic effects on the 661W cells, which are ascribed to endoplasmic reticulum (ER) stress and oxidative damages. ER stress inhibitor 4-PBA alleviated 661W cells apoptosis and oxidative stress. Subsequently, AUY922 was delivered into the vitreous cavity of mouse and induced selective photoreceptor death and visual impairments. Overactivation of neuroglial and retinal remodeling occurred during the degenerative process. Moreover, enhanced CHOP expression was tied to profound disturbances in redox homeostasis, which readied photoreceptors for apoptosis. The underlying mechanism should be attributed to the activation of the PERK-eIF2α-ATF4-CHOP pathway. AUY922 can compensate for the high toxicity and instability of traditional inducers in RD modeling. These results not only enrich our understanding of the toxicology of AUY922 but also provide clues for establishing reliable RD models.

A novel taxane SB-T-101141 triggers a noncanonical ferroptosis to overcome Paclitaxel resistance of breast cancer via iron homeostasis-related KHSRP

Acquired multidrug resistance impedes the clinical application of paclitaxel. Here, we disclosed that the taxane SB-T-101141 efficiently contributed to a novel ferroptosis-like cell death of Paclitaxel-resistant and parental breast cancer cells. Functionally, SB-T-101141 facilitated the production of iron and ferrous ions along with reactive oxygen species (ROS), composed of lipid ROS and lipid peroxidation-derived aldehydes, including malonaldehyde (MDA), and glutathione (GSH) depletion. Iron chelators and ROS scavengers significantly attenuated cell death, and the inorganic ROS rendered by SB-T-101141. However, the ferroptosis-associated lipid oxide inhibitors could not block the lipid ROS and cell death triggered by SB-T-101141. Meanwhile, via genome-scale CRISPR-Cas9 screening, we uncovered that SB-T-101141 bound to the KH-type splicing regulatory protein (KHSRP) to inhibit the iron-dependent expression of CDGSH iron sulfur domain 1 (CISD1) associated with iron homeostasis, which consequently led to a novel type of ferroptosis of breast tumors. Moreover, RNA deep sequencing indicated that SB-T-101141 synergistically enhanced the iron-dependent activation of JNK and PERK pathways via KHSRP. Altogether, our results here demonstrate the potential clinical application of SB-T-101141 as a novel ferroptosis inducer in Paclitaxel-resistant breast cancer treatment.

Unveiling the crosstalk between unfolded protein response and apoptosis in triclosan induced hepatotoxicity in Labeo rohita

Triclosan (TCS), a widely used antimicrobial, has emerged as a concerning aquatic pollutant, especially post-COVID-19 due to increased disinfectant use. The study aimed to investigate the toxic impacts of TCS on Labeo rohita, revealing a 96-h LC50 of 0.742 mg/L. Well-acclimatized fish were categorised into three groups: one control and two treatment (T1 and T2) that were exposed to 1/10th and 1/5th of 96-h LC50 i.e., 0.0742 mg/L and 0.148 mg/L, respectively for 6 weeks under semi-static condition. Significantly (p < 0.05) elevated extents of reactive oxygen species (ROS) in the liver indicated enhanced oxidative stress. The activities of enzymatic antioxidants viz. superoxide dismutase (SOD) and catalase (CAT) were significantly (p < 0.05) increased while the reduced glutathione (GSH) levels were significantly (p < 0.05) decreased in a dose- and duration-dependent manner. A significant (p < 0.05) increase was observed in the lipid peroxidation (LPO) rate, which coincided with disruptions in the histological structure of the liver. Significant (p < 0.05) induction in Micronuclei frequency validated genomic instability. Furthermore, Endoplasmic Reticulum (ER) stress was marked by the increased intracellular calcium levels and elevated expression of grp78, chop, atf4, perk, eIF2α and gadd34 in TCS-exposed groups. Moreover, the consequent activation of bax, caspase-3, caspase-9, apaf-1 and the regulation of bcl-2 due to ER-stress, ultimately resulted in apoptosis of hepatocytes. Pearson correlation matrix and Principal Component Analysis (PCA) further underscored key interactions among parameters. Our findings demonstrate that the TCS, at its sub-lethal concentrations, is causing severe anomalies and even cell-death via triggering ER-stress-mediated apoptotic pathway in the fish liver.

Antiplatelet therapy as a novel approach in Parkinson's disease: Repositioning Ticagrelor to alleviate rotenone-induced parkinsonism via modulation of ER stress, apoptosis, and autophagy

Cardiovascular diseases, such as myocardial infarction, ischemic stroke, and coronary heart ailments have been closely associated with Parkinson's disease (PD). Despite this established link, the potential neuroprotective impact of the potent antiplatelet agent ticagrelor (Tica) remains unexplored against PD. Thus, we hypothesized that Tica could be repurposed as a therapeutic agent against PD. Rotenone experimental model was adopted in Wistar male rats by administering rotenone subcutaneously on alternate days during a 21-day experimental period and treating a subset of rats with Tica orally for the last 11 consecutive days. The administration of Tica improved motor function (open field test, hanging wire test) and restored striatal histological features. Additionally, Tica opposed the rotenone effect and markedly obliterated the striatal α-synuclein content but enhanced the protein expression of tyrosine hydroxylase and dopamine content. On the molecular level, Tica inhibited striatal endoplasmic reticulum stress (ERS) as evidenced by the downregulation of the ER-resident transmembrane sensor inositol-requiring enzyme 1 alpha and its downstream molecular targets, TNF receptor-associated factor 2 and c-Jun N-terminal kinase, along with a reduction in caspase-3 activity. On the other hand, Tica augmented the autophagy machinery by upregulating the autophagosome markers Beclin-1 and light chain 3-II, while inhibiting the content of cathepsin D. Therefore, the current study is the first to accentuate the neuroprotective potential of Tica in a rat model of PD via modulating the crosstalk between ERS, apoptosis, and autophagy to represent a potential novel therapeutic candidate for managing PD, particularly in patients with or prone to cardiovascular diseases.

Thermal acclimatization mechanisms in the cold-water Ophiuroid Ophiura sarsii vadicola: Regulation of protein homeostasis and metabolic pathways

Global climate change is driving rapid warming in the Pacific Arctic cold-water regions. As dominant species in these areas, the Ophiura sarsii complex suffer from ocean warming stress, resulting in altered distribution patterns, physiological behaviors, and thermotolerance. However, their molecular response mechanisms to ocean warming remain unclear. We conducted transcriptomic analyses of O. sarsii vadicola under various temperature treatments: a control group at in-situ temperature (7 °C), two warming groups at the sub-lethal temperature 19 °C for one week (short-term) and two months (long-term), and a low-temperature reference group of O. sarsii at 0 °C. The results showed that a total of 66 core differentially expressed genes (58 up-regulated, 8 downregulated) were identified, with expression patterns varying by warming duration. Ophiura sarsii vadicola exhibited a more pronounced response to long-term warming than short-term ones. Three transcription factors HMGB3, METTL19, and HEAT were identified as key regulators within the co-expression networks. Furthermore, changes in folding enzymes activity and an upregulation of protein processing and chaperone genes were observed, indicating a potential activation of the unfolded protein response in brittle stars. Elevated temperatures also induced changes in multiple energy metabolism-related pathways. These findings suggest that O. sarsii vadicola may mitigate the negative effects of ocean warming by regulating key gene expression, enhancing protein homeostasis control and energy redistribution. This study provides valuable insights into the evolution and adaptability mechanisms of cold-water species under global climate change.

Distinct systemic impacts of Aβ42 and Tau revealed by whole-organism snRNA-seq

Both neuronal and peripheral tissues become disrupted in Alzheimer's disease (AD). However, a comprehensive understanding of how AD impacts different tissues across the whole organism is lacking. Using Drosophila, we generated an AD Fly Cell Atlas (AD-FCA) based on whole-organism single-nucleus transcriptomes of 219 cell types from flies expressing AD-associated proteins, either human amyloid-β 42 peptide (Aβ42) or Tau, in neurons. We found that Aβ42 primarily affects the nervous system, including sensory neurons, while Tau induces accelerated aging in peripheral tissues. We identified a neuronal cluster enriched in Aβ42 flies, which has high lactate dehydrogenase (LDH) expression. This LDH-high cluster is conserved in 5XFAD mouse and human AD datasets. We found a conserved defect in fat metabolism from both fly and mouse tauopathy models. The AD-FCA offers new insights into how Aβ42 or Tau systemically and differentially affects a whole organism and provides a valuable resource for understanding brain-body communication in neurodegeneration.

ER stress and/or ER-phagy in drug resistance? Three coincidences are proof

Cancer is influenced by the tumor microenvironment (TME), which includes factors such as pH, hypoxia, immune cells, and blood vessels. These factors affect cancer cell growth and behavior. The tumor microenvironment triggers adaptive responses such as endoplasmic reticulum (ER) stress, unfolded protein response (UPR), and autophagy, posing a challenge to cancer treatment. The UPR aims to restore ER homeostasis by involving key regulators inositol-requiring enzyme-1(IRE1), PKR-like ER kinase (PERK), and activating transcription factor 6 (ATF6). Additionally, ER-phagy, a selective form of autophagy, eliminates ER components under stress conditions. Understanding the interplay between hypoxia, ER stress, UPR, and autophagy in the tumor microenvironment is crucial for developing effective cancer therapies to overcome drug resistance. Targeting the components of the UPR and modulating ER-phagy could potentially improve the efficacy of existing cancer therapies. Future research should define the conditions under which ER stress responses and ER-phagy act as pro-survival versus pro-death mechanisms and develop precise methods to quantify ER-phagic flux in tumor cells.

Metformin attenuates endoplasmic reticulum stress in diabetic kidney disease: mechanistic insights and future perspectives

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes that can lead to end-stage renal failure. Emerging evidence suggests that endoplasmic reticulum (ER) stress plays a crucial role in the pathogenesis of DKD by affecting various renal parenchymal cells, including endothelial cells, podocytes, and mesangial cells. This review comprehensively examines the relationship between ER stress and DKD, focusing on how metformin, a first-line antidiabetic medication, ameliorates ER stress-induced kidney injury. Multiple factors, including reactive oxygen species (ROS), proteinuria, and advanced glycation end products (AGEs), contribute to ER stress in DKD. Metformin's renoprotective effects are primarily mediated through activation of the AMPK signaling pathway, which modulates ER stress response, reduction of oxidative stress and its impact on ER function, and improvement of mitochondrial function. These mechanisms collectively lead to decreased proteinuria, reduced cell apoptosis, and attenuated epithelial-mesenchymal transition in diabetic kidneys. Understanding these molecular mechanisms provides new insights into the therapeutic potential of metformin in DKD treatment. However, further research is needed to elucidate the precise molecular pathways through which metformin regulates ER stress in different renal cell types under diabetic conditions.

Cisd1 synergizes with Cisd2 to modulate protein processing by maintaining mitochondrial and ER homeostasis

Connection and crosstalk among the organelles critically contribute to cellular functions. Destruction of any kind of organelle is likely to induce a series of intracellular disorders and finally lead to cell death. Because of its subcellular locations, CDGSH iron-sulfur domain-containing protein 1 (Cisd1) and Cisd2 have functions that are related to maintaining mitochondria and ER homeostasis. As previous reports have shown, Cisd2 knockout mice have a decreased body weight and poor survival rate, and the primary defects were conducted in skeletal muscle. Our previous findings indicated that Cisd1 deletion causes a range of skeletal muscle defects in mice with Cisd2 deficiency, including mitochondrial degeneration, endoplasmic reticulum (ER) stress, and alteration of protein process, as well as programmed cell death. In Cisd1 and Cisd2 deficient condition, the whole of the protein biosynthesis was damaged, including translation, modification, transport, and degradation. Changes in the immune response, redox regulation, and metabolism were also present in Cisd1 and Cisd2 double knockout mice. Overall, we have demonstrated that Cisd1 and Cisd2 knockout have a synergistic effect on skeletal muscles, and that Cisd2 plays a more critical role than Cisd1. These synergistic effects impact signaling regulation and interrupt the crosstalk and homeostasis of organelles. This creates severe disorders in various tissues and organs.

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.

Regulation of PEST-containing nuclear proteins in cancer cells: implications for cancer biology and therapy

The PEST-containing nuclear protein (PCNP) is a nuclear protein involved in the regulation of cell cycle progression, protein degradation, and tumorigenesis. PCNP contains a PEST sequence, a polypeptide structural motif rich in proline (P), glutamic acid (E), serine (S), and threonine (T), which serves as a proteolytic recognition signal. The degradation of specific proteins via the PEST sequence plays a crucial role in modulating signaling pathways that control cell growth, differentiation, apoptosis, and stress responses. PCNP is primarily degraded through the ubiquitin-proteasome system (UPS) and the calpain pathway, with phosphorylation of threonine and serine residues further accelerating its degradation. The ubiquitination of PCNP by the ring finger protein NIRF in an E3 ligase-dependent manner is well documented, along with its involvement in the MAPK and PI3K/AKT/mTOR signaling pathways. Additionally, PCNP is implicated in p53-mediated cell cycle arrest and apoptosis, which are essential for inhibiting tumor growth. To explore the role of PCNP in cancer, this review examines its effects on cell growth, differentiation, proliferation, and apoptosis in lung adenocarcinoma, thyroid cancer, ovarian cancer, and other malignancies derived from glandular epithelial cells. By focusing on PCNP and its regulatory mechanisms, this study provides a scientific basis for further research on the biological functions of the PEST sequence in tumor development and cancer progression.

Effect of 2,5-hexanedione on rat ovarian granulosa cell apoptosis involves endoplasmic reticulum stress-dependent m-TOR signaling pathway

Occupational exposure to N-hexane/2,5-hexanedione (2,5-HD) was found to adversely affect reproductive functions in females. However, there are few studies regarding the mechanisms underlying reproductive system damage initiated by 2,5-HD. Several studies demonstrated that 2,5-HD exerts hormonal dysfunctions in females by promoting apoptosis using rat ovarian granulosa cells (GCs) as a model. The endoplasmic reticulum (ER) plays a key role in cellular processes such as protein folding and modification, Ca2+ storage, and lipid synthesis, which are known to involve the activation of stress (ERS)-dependent m-TOR signaling pathway. Thus, the aim of this study was to examine the effects of 2,5-HD on ER and the associated activation of stress (ERS)-dependent m-TOR signaling pathway resulting in consequent apoptosis of ovarian GCs. Data demonstrated that after intraperitoneal treatment with 100, 200, or 400 mg/kg 2,5-HD for 6 consecutive weeks, 5 times per week, a decrease in body weight, ovarian weight, and relative ovary weight was found. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed that 2,5-HD promoted apoptosis of ovarian GCs, which involved enhanced relative protein expression levels of m-TOR/p-mTOR. Our findings demonstrated that 2,5-HD (1) elevated expression levels of pro-apoptosis-related genes Bax and Caspase 3, (2) decreased expression levels of the anti-apoptosis gene Bcl-2, and (3) activated the protein expression of glucose-regulatory protein 78 (GRP78), inositol-requiring enzyme-1 (IRE1), and c-Jun terminal kinase (JNK) associated with increased apoptosis. Evidence indicates that chronic exposure to 2,5-HD induced apoptosis of ovarian GCs, and the possible mechanism underlying this effect involves the ERS-dependent m-TOR signaling pathway.

Inflammation and cancer cell survival: TRAF2 as a key player

TNF receptor-associated factor 2 (TRAF2) plays a crucial role in both physiological and pathological processes. It takes part in the regulation of cell survival and death, tissue regeneration, development, endoplasmic reticulum stress response, autophagy, homeostasis of the epithelial barrier and regulation of adaptive and innate immunity. Initially identified for its interaction with TNF receptor 2 (TNFR2), TRAF2 contains a TRAF domain that enables homo- and hetero-oligomerization, allowing it to interact with multiple receptors and signaling molecules. While best known for mediating TNFR1 and TNFR2 signaling, TRAF2 also modulates other receptor pathways, including MAPK, NF-κB, and Wnt/β-catenin cascades. By regulating NF-κB-inducing kinase (NIK), TRAF2 is a key activator of the alternative NF-κB pathway, linking it to inflammatory diseases, immune dysfunction, and tumorigenesis. In the innate immune system, TRAF2 influences macrophage differentiation, activation, and survival and stimulates natural killer cell cytotoxicity. In the adaptive immune system, it represses effector B- and T-cell activity while sustaining regulatory T-cell function, thus promoting immune suppression. The lack of fine-tuning of TRAF2 activity leads to excessive NF-kB activation, driving chronic inflammation and autoimmunity. Although TRAF2 can act as a tumor suppressor, it is predominantly described as a tumor promoter, as its expression has been correlated with increased metastatic potential and poorer prognosis in several types of cancer. Targeting TRAF2 or TRAF2-dependent signaling pathways might represent a promising anti-cancer therapeutic strategy.

MDM2 inhibitor induces apoptosis in colon cancer cells through activation of the CHOP-DR5 pathway, independent of p53 phenotype

Introduction

Murine double minute 2 (MDM2), a key negative regulator of p53, forms a feedback loop with p53 to drive tumor progression, including colorectal cancer. Nutlin-3a, an MDM2 inhibitor, induces apoptosis in wild-type p53 tumors, but its effects on p53-mutated cancers and potential p53-independent apoptotic mechanisms remain unclear.

Methods

We investigated Nutlin-3a's effects on colon cancer cells with varying p53 phenotypes. Endoplasmic reticulum (ER) stress-associated CHOP was detected and knocked down to explore mechanisms. In vitro and in vivo experiments assessed Nutlin-3a's synergy with 5-fluorouracil and TRAIL.

Results

Nutlin-3a activated caspase-8-dependent extrinsic apoptosis in colon cancer cells via DR5 upregulation, independent of p53 status. ER stress and CHOP activation mediated DR5 induction, driven by calcium release. Combined Nutlin-3a treatment enhanced sensitivity to 5-fluorouracil and TRAIL in vitro and in vivo through caspase-8 pathway activation.

Discussion

These findings reveal a novel p53-independent apoptotic mechanism of Nutlin-3a involving ER stress and death receptor signaling. This pathway highlights Nutlin-3a's potential as an adjuvant therapy for colon cancer, even in p53-mutated tumors, by enhancing chemotherapeutic efficacy through extrinsic apoptosis.

Identification of Omaveloxolone as An Endoplasmic Reticulum Associated Degradation Inhibitor That Induces Early Apoptotic Signaling in Multiple Myeloma

Endoplasmic reticulum-associated degradation (ERAD) is essential for maintaining protein homeostasis, yet its regulatory mechanisms remain poorly understood. A major challenge in studying ERAD is the lack of specific inhibitors targeting the ERAD complex. To address this, we conducted a cell-based high-throughput screen using the FDA-repurposing library and identified omaveloxolone (RTA408) as a potent ERAD inhibitor that selectively impairs the degradation of ER luminal and membrane substrates. Beyond its utility in identifying ERAD substrates, RTA408 exhibits strong cytotoxic effects in multiple myeloma (MM), an incurable plasma cell malignancy. RTA408 inhibits ERAD activity and rapidly induces apoptotic signaling via caspase 8 and the death-inducing signaling complex (DISC). Notably, RTA408 is cytotoxic to malignant plasma cells, including those resistant to proteasome inhibitors, and demonstrates in vivo anti-myeloma activity. Our findings establish ERAD inhibitors as valuable tools for dissecting ERAD regulation while also highlighting their potential as therapeutic agents for MM.

Highlights

We developed a cell-based screening approach to identify novel modulators of endoplasmic reticulum associated degradation (ERAD), with implications in studying ERAD biology and targeting plasma cell neoplasms.Screening of the FDA-repurposing library identified Omaveloxolone (RTA408) as an inhibitor of luminal and membrane ERAD substrate degradation, which can be leveraged to identify ERAD substrates.maveloxolone treatment rapidly induces the unfolded protein response and apoptosis that is dependent on caspase 8 and death-inducing signaling complex (DISC) in multiple myeloma cells. maveloxolone exhibits cytotoxic effects against multiple myeloma cells in vitro and in vivo and induces apoptosis in primary plasma cells from patients with relapsed/refractory myeloma.

Hantaan virus infection induces human mucosal-associated invariant T cell pyroptosis through IRE1α pathway

Hantaan virus (HTNV) triggers an epidemic of hemorrhagic fever with renal syndrome (HFRS), which is predominantly prevalent in Asia. Mucosal-associated invariant T (MAIT) cells, categorized as innate-like T lymphocytes, perform crucial functions in the innate host defense mechanism during virus infection. We previously showed that MAIT cells played antiviral roles in vitro. But marked reduction of MAIT cells was present in the peripheral blood of HFRS patients. Till now, the role of MAIT cells in vivo and the mechanisms of HTNV-induced the MAIT cell deficiency have not yet been fully explored. In this study, by combining the clinical samples, MAIT deficiency mice and in vitro infected MAIT cell models, we find that pyroptosis was the main reason of MAIT cell loss in the peripheral blood of HFRS patients. The molecular mechanisms are related to the overload of calcium in the endoplasmic reticulum (ER) of MAIT cells, which subsequently induces inosital-requiring enzyme-1α (IRE1α)-mediated ER-stress and following pyroptosis. ER-stress inhibitor can reverse the pyroptosis of MAIT cells during HTNV infection. In conclusion, this study firstly reveals the underlying molecular mechanisms for the deficiency of MAIT cells during HTNV infection, and suggests a potential way to stabilize the MAIT cells population in HFRS.

The Hsa_circ_0105558/miR-182-5p/ATF6 Cascade Affects H2O2-Triggered Oxidative Damage and Apoptosis of Human Lens Epithelial Cells

Age-related cataract (ARC) is the prevalent cause of useful vision loss. Circular RNAs are related to ARC pathogenesis partly through their competing endogenous RNA (ceRNA) activity. Herein, we defined the action of hsa_circ_0105558 in hydrogen peroxide (H2O2)-driven apoptosis and oxidative damage in human lens epithelial SRA01/04 cells. Hsa_circ_0105558, microRNA (miR)-182-5p and activating transcription factor 6 (ATF6) were evaluated by a qRT-PCR or immunoblotting method. The hsa_circ_0105558/miR-182-5p and miR-182-5p/ATF6 relationships were predicted by bioinformatics analysis and confirmed by dual-luciferase reporter assay. Reactive oxygen species level, glutathione peroxidase level, superoxide dismutase activity, and malondialdehyde level were measured using the matched assay kits. Hsa_circ_0105558 was upregulated in human ARC lens and H2O2-exposed SRA01/04 cells. Suppression of hsa_circ_0105558 attenuated H2O2-driven SRA01/04 cell apoptosis and oxidative damage. Hsa_circ_0105558 targeted miR-182-5p, and reduced miR-182-5p expression reversed the influence of hsa_circ_0105558 depletion on H2O2-driven oxidative damage and apoptosis. ATF6 was a target of miR-182-5p, and miR-182-5p-driven downregulation of ATF6 regulated cell oxidative damage and apoptosis under H2O2 insult. Moreover, hsa_circ_0105558 functioned as a ceRNA to post-transcriptionally control ATF6 expression through miR-182-5p competition. Our study demonstrates that hsa_circ_0105558 modulates SRA01/04 cell oxidative damage and apoptosis under H2O2 insult through the miR-182-5p/ATF6 cascade.

Unveiling the impact of ERAP1 and ERAP2 on migration, angiogenesis and ER stress response

Recent studies have investigated the key roles exerted by ERAP1 and ERAP2 in maintaining cellular homeostasis, emphasizing their functions beyond traditional antigen processing and presentation. In particular, genetic variants of these IFNγ-inducible aminopeptidases significantly impact critical cellular pathways, including migration, angiogenesis, and autophagy, which are essential in immune responses and disease processes. ERAP1's influence on endothelial cell migration and VEGF-driven angiogenesis, along with ERAP2's role in managing stress-induced autophagy via the UPR, highlights their importance in cellular adaptation to stress and disease outcomes, including autoimmune diseases, cancer progression, and infections. By presenting recent insights into ERAP1 and ERAP2 functions, this review underscores their potential as therapeutic targets in immune regulation and cellular stress-response pathways.

The role of endoplasmic reticulum stress in type 2 diabetes mellitus mechanisms and impact on islet function

Type 2 diabetes mellitus (T2DM) is a globally prevalent metabolic disorder characterized by insulin resistance and dysfunction of islet cells. Endoplasmic reticulum (ER) stress plays a crucial role in the pathogenesis and progression of T2DM, especially in the function and survival of β-cells. β-cells are particularly sensitive to ER stress because they require substantial insulin synthesis and secretion energy. In the early stages of T2DM, the increased demand for insulin exacerbates β-cell ER stress. Although the unfolded protein response (UPR) can temporarily alleviate this stress, prolonged or excessive stress leads to pancreatic cell dysfunction and apoptosis, resulting in insufficient insulin secretion. This review explores the mechanisms of ER stress in T2DM, particularly its impact on islet cells. We discuss how ER stress activates UPR signaling pathways to regulate protein folding and degradation, but when stress becomes excessive, these pathways may contribute to β-cell death. A deeper understanding of how ER stress impacts islet cells could lead to the development of novel T2DM treatment strategies aimed at improving islet function and slowing disease progression.

Endoplasmic Reticulum Stress and Its Role in Metabolic Reprogramming of Cancer

Background/Objectives: Endoplasmic reticulum (ER) stress occurs when ER homeostasis is disrupted, leading to the accumulation of misfolded or unfolded proteins. This condition activates the unfolded protein response (UPR), which aims to restore balance or trigger cell death if homeostasis cannot be achieved. In cancer, ER stress plays a key role due to the heightened metabolic demands of tumor cells. This review explores how metabolomics can provide insights into ER stress-related metabolic alterations and their implications for cancer therapy. Methods: A comprehensive literature review was conducted to analyze recent findings on ER stress, metabolomics, and cancer metabolism. Studies examining metabolic profiling of cancer cells under ER stress conditions were selected, with a focus on identifying potential biomarkers and therapeutic targets. Results: Metabolomic studies highlight significant shifts in lipid metabolism, protein synthesis, and oxidative stress management in response to ER stress. These metabolic alterations are crucial for tumor adaptation and survival. Additionally, targeting ER stress-related metabolic pathways has shown potential in preclinical models, suggesting new therapeutic strategies. Conclusions: Understanding the metabolic impact of ER stress in cancer provides valuable opportunities for drug development. Metabolomics-based approaches may help identify novel biomarkers and therapeutic targets, enhancing the effectiveness of antitumor therapies.

Cellular Stress Responses and Associated Diseases: A Focus on Heat Shock Proteins

Cellular stress response is the response of the cell at molecular level in order to combat various environmental stressors / viral infections. These stressors can be either intra or extracellular. In the beginning of the insult cell tries to recoup from these adverse events by various mechanism like heat shock protein response, unfolded protein response, mitochondrial stress signaling, DNA damage response etc. However, if these stressors exceed the cellular capacity to coup with it, it leads to programmed cell death and senescence. Also, chronic stress and cortisol released in response to cellular stress decreases telomerase activity which is needed to replenish telomeres which are protective casing at the end of a strand of DNA. Too low telomeres lead to cell death or cell become pro-inflammatory leading to aging process and other health associated risks like cardiovascular diseases neurodegenerative diseases, autoimmune diseases, cancers etc.

Endoplasmic reticulum stress contributes to the development of ocular graft-vs-host disease in the eyelids and the ocular surface

BACKGROUND

While endoplasmic reticulum (ER) stress has been implicated in various aspects of graft-versus-host disease (GVHD), its effects on the eyelids and ocular surface in patients with chronic GVHD (cGVHD) remains poorly understood. We aimed to investigate the relationship between ER stress and ocular GVHD using the ER stress suppressor, 4-phenylbutyric acid (PBA).

METHODS

The study used allogeneic bone marrow transplantation (BMT) and syngeneic BMT to establish a cGVHD mouse model. cGVHD mice were treated with either intraperitoneal administration of PBA or 2 % PBA eye drops following BMT.

RESULTS

The Intraperitoneal PBA-treated (PBAip) group retained a larger meibomian gland (MG) area and corneal epithelial damage and inflammatory and fibrotic cell infiltration in the ocular surface was attenuated compared to vehicle-treated cGVHD mice. The expression of unfolded protein response markers was significantly elevated in the vehicle group compared to the syngeneic control and the PBAip group. Electron microscopy and immunohistochemistry revealed that fibroblasts and macrophages infiltrated the eyelids and ocular surface of cGVHD mice under ER stress. The corneal fluorescein staining score was significantly lower in the PBA eye drop-treated group than in the vehicle-treated group. The numbers of leukocyte marker CD45-, T cell marker CD4-, and macrophage marker F4/80-positive cells were significantly reduced in the PBA eye drop-treated group compared to the vehicle group.

CONCLUSIONS

The study suggests that the ER stress response, which is triggered by cGVHD in ocular surface tissues, can be suppressed by PBA, an ER stress suppressor, potentially offering therapeutic benefits in ocular GVHD.

Seneca Valley virus induces mitochondrial apoptosis by activating ER stress or the PERK pathway based on Ca2+ transfer from ER to mitochondria

Seneca Valley virus (SVV), also known as Senecavirus A, a porcine pathogen that causes vesicular diseases, is prevalent in pig herds worldwide. SVV infection induces endoplasmic reticulum (ER) stress in PK-15 and BHK-21 cells, accompanied by activation of the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) and activating transcription factor 6 (ATF6) pathways, which in turn facilitates SVV replication. ER stress is associated with the regulation of Ca2+ homeostasis and mitochondrial apoptosis. However, the precise role of Ca2+ in SVV-induced apoptosis remains unclear. In this study, western blotting, flow cytometry, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) detection revealed that either ER stress or the PERK pathway is involved in the apoptosis of SVV-infected cells treated with specific inhibitors. Furthermore, SVV-mediated ER stress markedly contributed to the transfer of Ca2+ from the ER to mitochondria. The subsequent increase in mitochondrial Ca2+ content was accompanied by an increased number of ER membranes near the mitochondria. Finally, the inhibition of mitochondrial Ca2+ overload, ER stress, and the PERK pathway substantially attenuated SVV-mediated mitochondrial dysfunction, as evidenced by analyzing mitochondrial membrane potential (MMP), mitochondrial permeability transition poremPTP, reactive oxygen speciesROS, and adenosine 5'-triphosphate ATP, and the levels of mitochondrial apoptosis. These findings demonstrate that SVV induces mitochondrial apoptosis, which is dependent on ER stress-mediated transmission of Ca2+ from the ER to the mitochondria.

IMPORTANCE

Viruses have developed multiple mechanisms to facilitate their proliferation or persistence through manipulating various organelles in cells. Seneca Valley virus (SVV), as a novel emerging pathogen associated with vesicular disease, is clinically and economically important infections that affect farm animals. Previously, we had confirmed that SVV-induced endoplasmic reticulum (ER) stress benefited for viral replication. Ca2+, as an intracellular signaling messenger mainly stored in the ER, is regulated by ER stress and then involved in apoptosis. However, the precise mechanism that Ca2+ transfer induced by SVV infection triggered apoptosis remained unclear. Here, we found that SVV infection triggered the Ca2+ transform from ER to mitochondria, resulting in mitochondrial dysfunction, and finally induced mitochondrial apoptosis. Our study shed light on a novel mechanism revealing how ER stress manipulates Ca2+ homeostasis to induce mitochondrial apoptosis and regulate viral proliferation.

Cell Homeostasis or Cell Death-The Balancing Act Between Autophagy and Apoptosis Caused by Steatosis-Induced Endoplasmic Reticulum (ER) Stress

Metabolic-dysfunction-associated steatotic liver disease (MASLD) is a prevalent liver condition with potential progression to cirrhosis and impaired regeneration post-resection. A key mechanism underlying lipotoxicity is endoplasmic reticulum (ER) stress, particularly the activation of the unfolded protein response (UPR). This study investigates the interplay between lipid accumulation, endoplasmic reticulum (ER) stress, and cellular outcomes, focusing on the balance between autophagy and apoptosis. We cultured primary human hepatocytes (PHH) in a free fatty acid (FFA)-enriched medium for 120 h, assessing lipid accumulation, metabolism, and the expression of selected UPR markers. Additionally, we investigated the effects of lipid load on cell activity and growth in proliferating HepG2 cells. We observed that FFA uptake consistently induced ER stress, shifting cellular responses toward apoptosis under high lipid loads. Donor-specific differences were evident, particularly in lipid storage, excretion, and sensitivity to lipotoxicity. Some donors exhibited limited triglyceride (TAG) storage and excretion, leading to an excess of FFA whose metabolic fate remains unclear. Proliferation was more sensitive to lipid accumulation than overall cell activity, with even low FFA concentrations impairing growth, highlighting the vulnerability of regenerative processes to steatosis. The study elucidates how ER stress pathways, such as PERK-CHOP and IRE1α-JNK, are differentially activated in response to lipid overload, tipping the balance toward apoptosis in severe cases. The limited activation of repair mechanisms, such as autophagy, further emphasizes the critical role of ER stress in determining hepatocyte fate. The donor-dependent variability highlights the need for personalized strategies to mitigate lipotoxic effects and enhance liver regeneration in steatosis-related conditions.

Chronic Antibody-Mediated Rejection and Plasma Cell ER Stress: Opportunities and Challenges with Calcineurin Inhibitors

Chronic alloantibody-mediated rejection (cAMR) remains a major challenge in transplant immunology, with no FDA-approved targeted therapies currently available. Despite advancements in cellular immunosuppression, effective strategies to mitigate alloantibody-mediated rejection are still lacking. This review provides a comprehensive overview of transplant rejection with a particular focus on the pathophysiology and therapeutic landscape of cAMR. We highlight the role of plasma cell-driven alloantibody production and its susceptibility to endoplasmic reticulum (ER) stress, a pathway with potential for therapeutic intervention. Special attention is given to calcineurin inhibitors (CNIs), which, beyond their well-established T-cell inhibitory effects, exhibit differential impacts on ER stress and plasma cell viability. By delineating the mechanistic differences between cyclosporine and tacrolimus in regulating ER stress responses, we propose potential therapeutic implications for optimizing cAMR management. This review underscores the need for innovative strategies targeting plasma cell biology to improve long-term transplant outcomes.

Cannabinoids Activate Endoplasmic Reticulum Stress Response and Promote the Death of Avian Retinal Müller Cells in Culture

BACKGROUND/OBJECTIVES

Activation of cannabinoid CB1 or CB2 receptors induces the death of glial progenitors from the chick retina in culture. Here, by using an enriched retinal glial cell culture, we characterized some mechanisms underlying glial death promoted by cannabinoids.

METHODS AND RESULTS

Retinal cultures obtained from 8-day-old (E8) chick embryos and maintained for 12-15 days (C12-15) were used. MTT assays revealed that the CB1/CB2 agonist WIN 55,212-2 (WIN) decreased cell viability in the cultures in a time-dependent manner, with a concomitant increase in extracellular LDH activity, suggesting membrane integrity loss. Cell death was also dose-dependently induced by cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), and CP55940, another CB1/CB2 agonist. In contrast to WIN-induced cell death that was not blocked by either antagonist, the deleterious effect of CBD was blocked by the CB2 receptor antagonist SR144528, but not by PF514273, a CB1 receptor antagonist. WIN-treated cultures showed glial cells with large vacuoles in cytoplasm that were absent in cultures incubated with WIN plus 4-phenyl-butyrate (PBA), a chemical chaperone. Since cannabinoids induced the phosphorylation of eukaryotic initiation factor 2-alfa (eIF2α), these results suggest a process of endoplasmic reticulum (ER) swelling and stress. Incubation of the cultures with WIN for 4 h induced a ~five-fold increase in the number of cells labeled with the ROS indicator CM-H2DCFDA. WIN induced the phosphorylation of JNK but not of p38 in the cultures, and also induced an increase in the number of glial cells expressing cleaved-caspase 3 (c-CASP3). The decrease in cell viability and the expression of c-CASP3 was blocked by salubrinal, an inhibitor of eIF2α dephosphorylation.

CONCLUSIONS

These data suggest that cannabinoids induce the apoptosis of glial cells in culture by promoting ROS production, ER stress, JNK phosphorylation, and caspase-3 processing. The graphical abstract was created at Biorender.com.

7-Hydroxycannabidiol and 7-carboxycannabidiol induced cytotoxicity via apoptosis and endoplasmic reticulum stress in human hepatic cells

Cannabidiol (CBD), a major component of extract from the plant Cannabis sativa L., has demonstrated efficacy in treating childhood-onset epilepsy; however, animal studies and clinical trials have reported elevated liver enzymes after CBD use, suggesting potential liver toxicity. In a previous study, we demonstrated that CBD caused cytotoxicity with apoptosis and endoplasmic reticulum (ER) stress in human hepatic cells. In the present study, we investigated the toxicity profile of the two main metabolites of CBD, 7-hydroxy-CBD and 7-carboxy-CBD, in primary human hepatocytes and HepG2 cells. Our findings indicated that both metabolites induced cellular damage similar to the parent drug in these cells. 7-Hydroxy-CBD and 7-carboxy-CBD also caused cell cycle disturbances, apoptosis, and ER stress in HepG2 cells. Additionally, we explored the role of cytochrome P450 (CYP) in the metabolism of 7-hydroxy-CBD and 7-carboxy-CBD using HepG2 cell lines expressing 14 individual CYPs. We determined that 7-hydroxy-CBD is metabolized by CYP2D6, and CYP2D6-mediated metabolism attenuated the cytotoxicity, apoptosis, and ER stress induced by 7-hydroxy-CBD. The CYPs did not metabolize 7-carboxy-CBD. In summary, our findings highlight the mechanisms underlying cytotoxicity induced by 7-hydroxy-CBD and 7-carboxy-CBD in hepatic cells.

The PERK-eIF2α-ATF4 Axis Is Involved in Mediating ER-Stress-Induced Ferroptosis via DDIT4-mTORC1 Inhibition and Acetaminophen-Induced Hepatotoxicity

Ferroptosis, a regulated form of cell death characterized by lipid peroxidation and iron accumulation, is increasingly recognized for its role in disease pathogenesis. The unfolded protein response (UPR) has been implicated in both endoplasmic reticulum (ER) stress and ferroptosis-mediated cell fate decisions; yet, the specific mechanism remains poorly understood. In this study, we demonstrated that ER stress induced by tunicamycin and ferroptosis triggered by erastin both activate the UPR, leading to the induction of ferroptotic cell death. This cell death was mitigated by the application of chemical chaperones and a ferroptosis inhibitor. Among the three arms of the UPR, the PERK-eIF2α-ATF4 signaling axis was identified as a crucial mediator in this process. Mechanistically, the ATF4-driven induction of DDIT4 plays a pivotal role, facilitating ferroptosis via the inhibition of the mTORC1 pathway. Furthermore, acetaminophen (APAP)-induced hepatotoxicity was investigated as a model of eIF2α-ATF4-mediated ferroptosis. Our findings reveal that the inhibition of eIF2α-ATF4 or ferroptosis protects against APAP-induced liver damage, underscoring the therapeutic potential of targeting these pathways. Overall, this study not only clarifies the intricate role of the PERK-eIF2α-ATF4 axis in ER-stress-and erastin-induced ferroptosis but also extends these findings to a clinically relevant model, providing a foundation for potential therapeutic interventions in conditions characterized by dysregulated ferroptosis and ER stress.

PSMC2 promotes resistance against temozolomide in glioblastoma via suppressing JNK-mediated autophagic cell death

Temozolomide is universally used to treat glioblastoma due to its unique ability to cross the blood-brain barrier and inhibit tumor growth through DNA alkylation. However, over time, the inevitable emergence of resistance to temozolomide impedes successful treatment of this cancer. As a result, there is an urgent need to identify new therapeutic targets to improve treatment outcomes for this malignancy. In this work, acquired temozolomide-resistant glioblastoma cell lines LN18 (LN18-TR) and T98G (T98G-TR) exhibited stronger aggressiveness and lower endoplasmic reticulum (ER) stress than their parental cells.. Besides, temozolomide resistance was associated with elevated proteasome activity that suppressed ER stress, which was restored upon inhibition of the proteasome with MG132. Specifically, our study revealed that the 19S proteasomal regulatory subunit PSMC2, which was overexpressed in adapted temozolomide-resistant glioblastoma cells, reduced pro-death autophagy and decreased temozolomide sensitivity in parental cells when overexpressed. While autophagy increased in parental cells following temozolomide treatment, it was not elevated in temozolomide-resistant glioblastoma cells. Genetic suppression of PSMC2 triggered the JNK signalling pathway causing phosphorylation of BCL2, allowing Beclin1 to be released from the BCL2-Beclin1 complex. This boosted autophagosome nucleation, increased pro-death autophagy, and restored apoptosis in temozolomide-resistant glioblastoma cells. Finally, targeting PSMC2 provided a unique method for interrupting autophagy-mediated ER stress maintenance and temozolomide resistance in glioblastoma.

Increased intracellular stress responses and decreased KLF2 in adult patients with atopic dermatitis

Atopic dermatitis (AD) is prone to exacerbations in response to various triggering factors and flare-ups after remission. We searched for molecules associated with relapse/exacerbation of AD among molecules with altered gene expression in the skin of patients with AD. Microarray analyses were performed on lesional and nonlesional skin of adolescent or adult patients with recalcitrant AD and healthy controls. Five chaperones involved in intracellular stress responses, namely heat shock protein family A (Hsp70) member 9 (HSPA9), heat shock protein 90 beta family member 1 (HSP90B1), calnexin (CANX), malectin (MLEC; endoplasmic reticulum-associated degradation), and heat shock protein family D (Hsp60) member 1 (HSPD1), were consistently upregulated in involved and uninvolved skin of patients with AD. Damage-associated molecular patterns were upregulated in involved skin. KLF transcription factor 2 (KLF2) was decreased in involved skin and exhibited a decreasing trend in uninvolved skin of patients with AD. CD4(+)/CD8(+) double-positive cells (1.4% of T cells) were detected in lesions with declined KLF2 levels. WNT inhibitory factor 1 (WIF1) was downregulated in involved skin. Prolactin-induced protein was upregulated in only uninvolved skin of patients with AD. We found increased intracellular stress responses and decreased expression of KLF2 in the skin of patients with AD. Multifactorial genetic diseases, such as asthma, inflammatory bowel disease, type 2 diabetes, and rheumatoid arthritis, are associated with intracellular stress. Intracellular abnormalities may also be responsible for AD. Further research on AD may incorporate enhanced intracellular stress response and the decreased expression of KLF2 into the mechanism underlying AD.

Polyamine-modified naphthalimide derivative 9C inhibits colorectal cancer through ROS-mediated ER stress, migration and invasion

Mounting evidence over the past decades has demonstrated the therapeutic potential of targeting endoplasmic reticulum (ER) stress signaling in cancer. Naphthalimdes exert their anti-cancer activities in a variety of ways. However, the effects of naphthalimides on ER stress are rarely reported. In this study, based on RNA-sequencing analysis, we observed that 9C, a naphthalimide derivative, could trigger ER stress to activate death receptor signaling and autophagy. Pretreatment of ER stress inhibitor, such as salubrinal, and autophagy inhibitor, such as 3-methyladenine (3-MA), partially reversed 9C-induced inhibition of cell growth. Furthermore, our results unveiled a reactive oxygen species (ROS)-dependent inhibitory effect of 9C. In addition, 9C inhibited colorectal cancer (CRC) cells migration and invasion. Removal of ROS using N-acetyl-L-cysteine (NAC) attenuated the expression of ATF4, CHOP, death receptors, E-cadherin, and the apoptosis and autophagy related proteins. Taken together, our results suggested that ROS-mediated ER stress, migration, and invasion is responsible for the therapeutic potential of naphthalimides including 9C in CRC.

Targeting p38 MAPK: A potential bridge between ER stress and age-related bone loss

The endoplasmic reticulum (ER) is crucial in the development of numerous age-related bone disorders. Notably, ER stress can precipitate bone loss by orchestrating inflammatory responses, apoptosis, and autophagy through the activation of the p38 MAPK pathway. Age-related bone loss diseases pose a significant burden on society and healthcare as the global population ages. This review provides a comprehensive analysis of recent research advancements, delving into the critical role of ER stress-activated p38 MAPK in inflammation, apoptosis, and autophagy, as well as its impact on bone formation and bone resorption. This review elucidates the molecular mechanisms underlying the involvement of ER stress-activated p38 MAPK in osteoporosis, rheumatoid arthritis, periodontitis, and osteoarthritis and discusses the therapeutic potential of targeting p38 MAPK. Furthermore, this review provides a scientific foundation for new therapeutic strategies by highlighting prospective research directions.

Aruncus Dioicus Var. Kamtschaticus Extract Prevents Ocular Endoplasmic Reticulum Stress, Inflammation, and Oxidative Stress In Vitro

The aim of this study was to determine the anti-inflammatory and anti-endoplasmic reticulum (ER) stress effects of Aruncus dioicus var. kamtschaticus (ADK) extract on ARPE-19 cells. Pretreatment with ADK effectively mitigated thapsigargin (Tg)-induced increases in vascular endothelial growth factor protein secretion and intracellular calcium levels. Furthermore, pretreatment with ADK suppressed ocular ER stress-related protein expression in a dose-dependent manner, inhibited the loss of tight junctions, and suppressed interleukin-6 gene expression. Moreover, ADK pretreatment significantly prevented lipopolysaccharide-inducible proinflammatory cytokine gene expression at the transcription level and the phosphorylation of proteins involved in the mitogen-activated protein kinase-nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) axis at the posttranslational level. Additionally, ADK extract enhanced antioxidant activity, as evidenced by increased heme oxygenase-1 protein expression and increased 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing antioxidant power. In conclusion, ADK extract effectively protected ARPE-19 cells from ocular ER stress, inflammation, and oxidative stress, demonstrating its potential as a nutraceutical intervention for ocular diseases.

Dolutegravir induces endoplasmic reticulum stress at the blood-brain barrier

Dolutegravir (DTG)-based antiretroviral therapy is the contemporary first-line therapy to treat HIV infection. Despite its efficacy, mounting evidence has suggested a higher risk of neuropsychiatric adverse effect (NPAE) associated with DTG use, with a limited understanding of the underlying mechanisms. Our laboratory has previously reported a toxic effect of DTG but not bictegravir (BTG) in disrupting the blood-brain barrier (BBB) integrity. The current study aimed to investigate the underlying mechanism of DTG toxicity. Primary cultures of mouse brain microvascular endothelial cells were treated with DTG and BTG at therapeutically relevant concentrations. RNA sequencing, qPCR, western blot analysis, and cell stress assays (Ca2+ flux, H2DCFDA, TMRE, MTT) were applied to assess the results. The gene ontology (GO) analysis revealed an enriched transcriptome signature of endoplasmic reticulum (ER) stress following DTG treatment. We demonstrated that therapeutic concentrations of DTG but not BTG activated the ER stress sensor proteins (PERK, IRE1, p-IRE1) and downstream ER stress markers (eIF2α, p-eIF2α, Hspa5, Atf4, Ddit3, Ppp1r15a, Xbp1, spliced-Xbp1). In addition, DTG treatment resulted in a transient Ca2+ flux, an aberrant mitochondrial membrane potential, and a significant increase in reactive oxygen species in treated cells. Furthermore, we found that prior treatment with ER sensor or ER stress inhibitors significantly mitigated the DTG-induced downregulation of tight junction proteins (Zo-1, Ocln, Cldn5) and elevation of pro-inflammatory cytokines and chemokines (Il6, Il23a, Il12b, Cxcl1, Cxcl2). The current study provides valuable insights into DTG-mediated cellular toxicity mechanisms, which may serve as a potential explanation for DTG-associated NPAEs in the clinic.

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.

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.

Characterization of canine tumor-infiltrating leukocyte transcriptomic signatures reveals conserved expression patterns with human osteosarcoma

Immune cells play key roles in host responses to malignant tumors. The selective pressure that immune cells elicit on tumors promotes immune escape, while tumor-associated modulation of immune cells creates an environment favorable to tumor growth and progression. In this study we used publicly available single-cell RNA sequencing (scRNA-seq) data from the translationally relevant canine osteosarcoma (OS) model to compare tumor-infiltrating immune cells to circulating leukocytes. Through computational analysis we investigated the differences in cell type proportions and how the OS TME impacted infiltrating immune cell transcriptomic profiles relative to circulating leukocytes. Differential abundance analysis revealed increased proportions of follicular helper T cells, regulatory T cells, and mature regulatory dendritic cells (mregDCs) in the OS TME. Differential gene expression analysis identified exhaustion markers (LAG3, HAVCR2, PDCD1) to be upregulated in CD4 and CD8 T cells within the OS TME. Comparisons of B cell gene expression profiles revealed an enrichment of protein processing and endoplasmic reticulum pathways, suggesting infiltrating B cells were activated following tumor infiltration. Gene expression changes within myeloid cells identified increased expression of immune suppressive molecules (CD274, OSM, MSR1) in the OS TME, indicating the TME skews myeloid cells toward an immunosuppressive phenotype. Comparisons to human literature and analysis of human scRNA-seq data revealed conserved transcriptomic responses to tumor infiltration, while also identifying species differences. Overall, the analysis presented here provides new insights into how the OS TME impacts the transcriptional programs of major immune cell populations in dogs and acts as a resource for comparative immuno-oncology research.

PERK-Olating Through Cancer: A Brew of Cellular Decisions

The type I protein kinase PERK is an endoplasmic reticulum (ER) transmembrane protein that plays a multifaceted role in cancer development and progression, influencing tumor growth, metastasis, and cellular stress responses. The activation of PERK represents one of the three signaling pathways induced during the unfolded protein response (UPR), which is triggered, in particular, in tumor cells that constitutively experience various intracellular and extracellular stresses that impair protein folding within the ER. PERK activation can lead to both pro-survival and proapoptotic outcomes, depending on the cellular context and the extent of ER stress. It helps the reprogramming of the gene expression in cancer cells, thereby ensuring survival in the face of oncogenic stress, such as replicative stress and DNA damage, and also microenvironmental challenges, including hypoxia, angiogenesis, and metastasis. Consequently, PERK contributes to tumor initiation, transformation, adaptation to the microenvironment, and chemoresistance. However, sustained PERK activation in cells can also impair cell proliferation and promote apoptotic death by various interconnected processes, including mitochondrial dysfunction, translational inhibition, the accumulation of various cellular stresses, and the specific induction of multifunctional proapoptotic factors, such as CHOP. The dual role of PERK in promoting both tumor progression and suppression makes it a complex target for therapeutic interventions. A comprehensive understanding of the intricacies of PERK pathway activation and their impact is essential for the development of effective therapeutic strategies, particularly in diseases like cancer, where the ER stress response is deregulated in most, if not all, of the solid and liquid tumors. This article provides an overview of the knowledge acquired from the study of animal models of cancer and tumor cell lines cultured in vitro on PERK's intracellular functions and their impact on cancer cells and their microenvironment, thus highlighting potential new therapeutic avenues that could target this protein.

A pharmacoinformatic approach for studying Atractylodes Lancea DC's anticancer potential and control ROS-mediated apoptosis against prostate cancer cells

Introduction

Prostate cancer (PCa) is a malignancy characterized by abnormal cell proliferation in the prostate gland, a critical component of the male reproductive system. Atractylodes lancea DC. (ALD), a medicinal herb commonly used in traditional Asian medicine, is highly regarded for its antioxidant, antidiabetic, and anticancer properties. Virtual docking stud-ies have identified Atractylenolide II and III as active components of ALD, demonstrating strong binding potential to inhibit androgen receptor (AR) activity, with docking scores of -8.9 and -9.3, respectively. These findings suggest that ALD may exert a synergistic effect comparable to or greater than that of enzalutamide (ENZ) in inhibiting AR. How-ever, its specific anticancer and anti-metastatic mechanisms in prostate cancer remain unclear.

Methods

The cytotoxic effects of ALD were evaluated on PC3 and DU145 prostate cancer cells, as well as on the normal prostate cell line BPH-1. Cell viability was assessed using the EZ-Cytotoxic kit, while colony formation assays and TUNEL staining were used to meas-ure proliferation and apoptosis, respectively. Apoptosis was further analyzed through an-nexin V-FITC/PI staining and quantified by flow cytometry (FACS). Western blotting was performed to elucidate the underlying molecular mechanisms. Additionally, mito-chondrial membrane potential (ΔΨm) and intracellular calcium levels were measured to evaluate mitochondrial function, while reactive oxygen species (ROS) generation was assessed with and without pretreatment with N-acetylcysteine (NAC) .

Results

ALD selectively reduced the viability of PC3 and DU145 prostate cancer cells while spar-ing BPH-1 normal prostate cells, demonstrating cancer-selective cytotoxicity. ALD dis-rupted mitochondrial function by reducing ΔΨm and increasing intracellular calcium lev-els. A concentration-dependent increase in ROS generation was observed in PC3 and DU145 cells, which was completely inhibited by NAC pretreatment, confirming a ROS-mediated mechanism. Colony formation assays revealed a significant reduction in prolif-eration, while TUNEL and annexin V-FITC/PI staining indicated enhanced apoptosis. Western blot analysis showed that ALD modulates critical survival pathways, leading to apoptotic cell death.

Discussion

These findings demonstrate that ALD exerts potent anticancer effects against metastatic prostate cancer cells through ROS-mediated apoptosis and mitochondrial dysfunction, while exhibiting minimal cytotoxicity toward normal prostate cells. The presence of ac-tive compounds such as Atractylenolide II and III suggests a synergistic interaction that enhances AR inhibition and promotes apoptosis. ALD's ability to engage multiple path-ways highlights its therapeutic potential as a selective and multifaceted treatment for ag-gressive prostate cancer.

Mutations in unfolded protein response regulator ATF6 cause hearing and vision loss syndrome

Activating transcription factor 6 (ATF6) is a key regulator of the unfolded protein response (UPR) and is important for ER function and protein homeostasis in metazoan cells. Patients carrying loss-of-function ATF6 disease alleles develop the cone dysfunction disorder achromatopsia. The effect of loss of ATF6 function on other cell types, organs, and diseases in people remains unclear. Here, we report that progressive sensorineural hearing loss was a notable complaint in some patients carrying ATF6 disease alleles and that Atf6-/- mice also showed progressive auditory deficits affecting both sexes. In mice with hearing deficits, we found disorganized stereocilia on hair cells and focal loss of outer hair cells. Transcriptomics analysis of Atf6-/- cochleae revealed a marked induction of the UPR, especially through the protein kinase RNA-like endoplasmic reticulum kinase (PERK) arm. These findings identify ATF6 as an essential regulator of cochlear health and function. Furthermore, they support the idea that ATF6 inactivation in people causes progressive sensorineural hearing loss as part of a blindness-deafness genetic syndrome targeting hair cells and cone photoreceptors. Last, our genetic findings indicate that ER stress is an important pathomechanism underlying cochlear damage and hearing loss, with clinical implications for patient lifestyle modifications that minimize environmental and physiological sources of ER stress to the ear.

The renoprotective effects of cannabidiol on lipopolysaccharide-induced systemic inflammation model of rats

Sepsis-induced renal damage poses a significant threat, necessitating effective therapeutic strategies. Cannabidiol (CBD) has beneficial effects on tissues and their functions by exhibiting antioxidant and anti-inflammatory effects. This study investigates the potential protective effects of CBD in mitigating lipopolysaccharide (LPS)-induced renal injury in Wistar Albino rats. Thirty-two Wistar Albino rats were categorized into control, LPS (5 mg/kg i.p.), LPS + CBD, and CBD (5 mg/kg i.p.) groups. After the experiment, samples were collected for biochemical, genetic, histopathological, and immunohistochemical analyses. Oxidative stress markers as total oxidant status (TOS) and total antioxidant status (TAS), oxidative stress index (OSI), superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), immune staining as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), caspase-3, gene expressions as nuclear factor erythroid 2-related factor 2 (NRF2), C/EBP homologous protein (CHOP), caspase-9, glucose-regulating protein 78 (GRP78), B-cell leukemia/lymphoma 2 (Bcl2), and tissue histology have been examined. The LPS-exposed group exhibited significant renal abnormalities, mitigated by CBD intervention in the LPS + CBD group. CBD reduced immunoexpression scores for TNF-α, caspase-3, and IL-10. Biochemically, CBD induced a positive shift in the oxidative balance, increasing TAS, SOD, and GPx, while decreasing TOS, OSI, and MDA levels. Genetic analyses highlighted CBD's regulatory impact on NRF2, CHOP, caspase-9, GRP78, and Bcl2, providing molecular insights into its protective role against LPS-induced renal damage. This study underscores CBD as a promising protective agent against sepsis-induced renal damage. Our findings could provide valuable insights into potential therapeutic avenues for addressing renal complications in sepsis.

A special focus on polyadenylation and alternative polyadenylation in neurodegenerative diseases: A systematic review

Neurodegenerative diseases (NDDs) are one of the prevailing conditions characterized by progressive neuronal loss. Polyadenylation (PA) and alternative polyadenylation (APA) are the two main post-transcriptional events that regulate neuronal gene expression and protein production. This systematic review analyzed the available literature on the role of PA and APA in NDDs, with an emphasis on their contributions to disease development. A comprehensive literature search was performed using the PubMed, Scopus, Cochrane, Google Scholar, Embase, Web of Science, and ProQuest databases. The search strategy was developed based on the framework introduced by Arksey and O'Malley and supplemented by the inclusion and exclusion criteria. The study selection was performed by two independent reviewers. Extraction and data organization were performed in accordance with the predefined variables. Subsequently, quantitative and qualitative analyses were performed. Forty-seven studies were included, related to a variety of NDDs, namely Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Disease induction was performed using different models, including human tissues, animal models, and cultured cells. Most investigations were related to PA, although some were related to APA or both. Amyloid precursor protein (APP), Tau, SNCA, and STMN2 were the major genes identified; most of the altered PA patterns were related to mRNA stability and translation efficiency. This review particularly underscores the key roles of PA and APA in the pathogenesis of NDDs through their mechanisms that contribute to gene expression dysregulation, protein aggregation, and neuronal dysfunction. Insights into these mechanisms may lead to new therapeutic strategies focused on the modulation of PA and APA activities. Further research is required to investigate the translational potential of targeting these pathways for NDD treatment.

Intermittent Fasting Improves Social Interaction and Decreases Inflammatory Markers in Cortex and Hippocampus

Autism spectrum disorder (ASD) is a psychiatric condition characterized by reduced social interaction, anxiety, and stereotypic behaviors related to neuroinflammation and microglia activation. We demonstrated that maternal exposure to Western diet (cafeteria diet or CAF) induced microglia activation, systemic proinflammatory profile, and ASD-like behavior in the offspring. Here, we aimed to identify the effect of alternate day fasting (ADF) as a non-pharmacologic strategy to modulate neuroinflammation and ASD-like behavior in the offspring prenatally exposed to CAF diet. We found that ADF increased plasma beta-hydroxybutyrate (BHB) levels in the offspring exposed to control and CAF diets but not in the cortex (Cx) and hippocampus (Hpp). We observed that ADF increased the CD45 + cells in Cx of both groups; In control individuals, ADF promoted accumulation of CD206 + microglia cells in choroid plexus (CP) and increased in CD45 + macrophages cells and lymphocytes in the Cx. Gestational exposure to CAF diet promoted defective sociability in the offspring; ADF improved social interaction and increased microglia CD206 + in the Hpp and microglia complexity in the dentate gyrus. Additionally, ADF led to attenuation of the ER stress markers (Bip/ATF6/p-JNK) in the Cx and Hpp. Finally, biological modeling showed that fasting promotes higher microglia complexity in Cx, which is related to improvement in social interaction, whereas in dentate gyrus sociability is correlated with less microglia complexity. These data suggest a contribution of intermittent fasting as a physiological stimulus capable of modulating microglia phenotype and complexity in the brain, and social interaction in male mice.

Propylparaben-induced endoplasmic reticulum stress triggers G2/M phase cell cycle arrest and initiates caspase-3-dependent apoptosis in human lung cells

BACKGROUND

Propylparaben (PrP) is commonly used as an antimicrobial agent in food, cosmetics, and pharmaceuticals. While recent studies have shown that PrP exposure can cause various disruptions in cellular physiology, the precise mechanisms behind these effects remain unclear.

OBJECTIVE

In this study, we sought to examine the cytotoxic effects of PrP exposure on human lung cells in a dose- and time-dependent manner. We utilized flow cytometry to analyze the expression of proteins associated with the cell cycle and apoptosis at the single-cell level.

RESULTS

Our results showed that PrP treatment leads to a significant upregulation of genes related to ER stress. The activation of ER stress results in a decrease in cyclin B1 levels, which subsequently causes cell cycle arrest at the G2/M phase. After 48 h of PrP exposure, the unfolded protein response (UPR) triggers an apoptotic signaling pathway, increasing the number of cells undergoing caspase-3-mediated apoptosis. Together, these physiological changes lead to a reduction in cell viability in the presence of PrP.

CONCLUSION

These findings suggest that PrP exerts harmful effects on human lung cells by activating ER stress, which can lead to apoptosis and cell cycle arrest.