The unfolded protein response (UPR) is a central adaptive mechanism that safeguards protein homeostasis in the endoplasmic reticulum (ER). In the heart, UPR signaling contributes to cellular remodeling and survival across a range of pathological contexts, including ischemia, pressure overload, and cardiometabolic stress. Among the three canonical UPR branches, the PKR-like ER kinase (PERK) pathway plays a critical role in modulating translational control and redox balance during stress adaptation. Despite its functional importance, the molecular dynamics of PERK activation and assembly remain incompletely understood. Here, we investigate the oligomerization behavior of PERK in living cells using advanced fluorescence microscopy. We identify a concentration-dependent mechanism of PERK self-association, as well as a distinct population of oligomeric PERK whose assembly state remains stable upon ER stress induction. These findings challenge the traditional view of stress-induced oligomerization as a prerequisite for PERK activation and suggest the existence of non-canonical modes of PERK assembly with potential regulatory significance.

Abstract Background Central nervous system (CNS) disorders arise from many initiating factors, yet they repeatedly culminate in shared cellular stress-response programs. We organize this phenomenon by defining a comprehensive stress adaptation network as a set of coupled sensing and eff ector loops spanning oxidative–mitochondrial control, neuroimmune regulation, excitability regulation, and proteostasis maintenance. Methods We review how two major phytocannabinoids, cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC), modulate these adaptive modules. CBD is non-intoxicating and acts as a pleiotropic modulator that shapes stress-linked signaling through diverse molecular targets, including cannabinoid receptor 1 (CB1), cannabinoid receptor 2 (CB2), and various non-cannabinoid receptors, whereas THC is an intoxicating partial agonist at CB1/CB2, with neurobehavioral effects that depend strongly on state and dose. Results Clinical evidence is strongest for purifi ed CBD in epilepsy and for standardized formulations of purified THC and CBD combinations in multiple sclerosis (MS) spasticity, while evidence in other neurodegenerative and sleepdisorders remains preliminary. Across these four adaptive domains, cannabinoids can alter redox tone, glial stateprograms, circuit stability, and autophagy or unfolded protein response (UPR) signaling. However, many mechanisticclaims are based mainly on preclinical systems and may vary with exposure, cell type, and disease stage. Conclusion We highlight translational priorities that include standardized chemotypes and formulations, exposure–response biomarkers, cell-type-specific biomarkers and functional endpoints, and trial designs that separate symptomatic effects from disease modification. Graphical Abstract

Aging differentially affects disease risks of various organs1. The endocrine organs undergo significant changes along aging. Clinical reports showed increased prevalence of thyroid disorders with age, especially hypothyroidism2. Primary hypothyroidism includes congenital, autoimmune, and iatrogenic causes, which can occur throughout the lifespan. But those with unknown aetiology increase dramatically (~5 fold) in the elderly (≥75 years old)3,4. In thyrocytes, accumulated thyroglobulin requires efficient protein folding in the endoplasmic reticulum (ER)5,6. When ER experiences protein folding defects, it activates the unfolded protein response (UPR), which determines the life-or-death cell fate. The most fundamental mediator in UPR signaling is inositol-requiring enzyme-1 alpha (IRE-1α)7. This study reports, for the first time, a highly conserved gene, Cellular retinoic acid binding protein 1 (Crabp1), critical to thyrocyte function in aging. CRABP1 acts by modulating clustering and activation of IRE-1α, thereby reducing thyrocyte ER stress.

Rice (Oryza sativa) is a major staple crop providing both calories and essential microelements such as Zn for humans. Understanding the molecular mechanisms involved in the control of Zn homeostasis may aid in optimizing Zn levels to improve rice growth and maximize its nutritional value. In this study, we aimed to decipher the precise function of ZINC TRANSPORTER1 (OsZIP1) in Zn uptake and the signaling pathways through which OsZIP1 responds to fluctuations in Zn bioavailability. In contrast to other members of the OsZIP family, OsZIP1 did not respond to Zn deficiency through binding of BASIC LEUCINE ZIPPER TRANSCRIPTION FACTOR50/48 (bZIP50/48) to canonical ZDRE elements. However, OsZIP1 was induced by both depletion and excess of Zn. Excessive Zn triggered Fe deficiency signaling and induced the accumulation of POSITIVE REGULATOR OF IRON DEFICIENCY RESPONSE 2 (OsPRI2), which in turn activated ABSCISIC ACID INSENSITIVE5 (OsABI5) expression and drove the upregulation of OsZIP1. By contrast, Zn depletion upregulated the expression of OsZIP1 via unfolded protein response (UPR) signaling. The nuclear isoform of BASIC LEUCINE ZIPPER TRANSCRIPTION FACTOR74 (bZIP74) , which was generated by alternative splicing in response to Zn depletion, bound to the modified unfolded protein response element (mUPRE) in the promoter of OsZIP1 and enhanced its expression. Our study reveals a pivotal role of a low-affinity transporter in fine-tuning Zn homeostasis and provides an essential node in the control of cellular Zn homeostasis at fluctuating Zn bioavailability.

The placenta is known to be critical in the etiology of preeclampsia. However, there is a subset of preeclampsia cases without identifiable placental pathology. We evaluated which clinical preeclampsia classification system best distinguishes preeclampsia with placental pathology from preeclampsia without placental pathology. We evaluated 5 placental pathological features in 197 placentas from patients with preeclampsia grouped by 3 clinical preeclampsia subclasses: (1) preeclampsia with calculated infant birthweight <10th percentile for gestational age (small for gestational age [SGA] preeclampsia) versus preeclampsia with birthweight ≥10th percentile for gestational age (not SGA preeclampsia); (2) preeclampsia with delivery before 34 weeks of gestation (early delivery preeclampsia) versus preeclampsia with delivery at or after 34 weeks of gestation (late delivery preeclampsia); and (3) preeclampsia with severe features versus preeclampsia without severe features. Clinical, histological and molecular findings in patients with preeclampsia were compared with normotensive patients, with and without SGA infants (N=1078 total). The SGA versus not small for gestational age preeclampsia classification system performed best (likelihood ratios [95% CI] for ≥3 of 5 placental pathological findings: 15.7 [6.5-38.1] in SGA preeclampsia versus not small for gestational age preeclampsia; 6.8 [4.3-10.8] in early delivery preeclampsia versus late delivery preeclampsia; and 5.2 [1.95-14.1] in preeclampsia with severe features versus preeclampsia without severe features; all P<0.0001). SGA preeclampsia and SGA normotensive placentas were abnormal and shared alterations in hypoxia, TNFα (tumor necrosis factor alpha), glycolysis, unfolded protein response, estrogen response, ultraviolet response, p53, TGFβ (transforming growth factor beta), and mTORC1 (mammalian target of rapamycin complex 1) signaling pathways. Classifying preeclampsia based on birthweight percentile for gestational age is the most useful system for consistently identifying preeclampsia associated with placental pathology.

Insulin resistance: The central node of convergence between unfolded protein response, diabetes, and cancer.

Chronic respiratory diseases (CRDs) such as asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung cancer, along with other CRDs, continue to be a major cause of morbidity and mortality globally and constitute a growing global health burden. There is growing evidence that the etiology of these conditions is primarily driven by organelle stress, specifically mitochondrial dysfunction and endoplasmic reticulum (ER) stress. Mitochondria, which are highly susceptible to environmental stressors such as hypoxia, pollution, and tobacco smoke, can fail, leading to epithelial cell apoptosis, metabolic dysregulation, fibrosis, excessive mitochondrial reactive oxygen species (mtROS), altered calcium signaling, and impaired mitophagy. Similarly, unresolved ER stress triggers maladaptive unfolded protein response signaling, which in turn promotes epithelial damage, mucus hypersecretion, fibroblast activation, and tumor growth. Through ROS signaling and calcium flux, crosstalk between the mitochondria and the ER amplifies these maladaptive pathways. Dysregulated autophagy can promote tissue remodeling, inflammation, and tumor survival when it is either impaired or excessive. Another layer is added by apoptosis, which upsets tissue homeostasis by excessive fibroblast survival or epithelial cell death. Chronic inflammation is fueled by immune dysregulation and perpetual organelle stress, which exacerbates disease progression and resistance to therapy. Promising treatment options include adenosine monophosphate-activated protein kinase - mammalian target of rapamycin (AMPK-mTOR) regulators, ER stress modulators, mitochondrial-targeted antioxidants, and immunometabolic therapies that target organelle stress pathways. This review summarizes current insights into organelle stress responses in CRDs, with a focus on their integration with autophagy, apoptosis, and inflammation, and highlights the future approaches for precision medicine therapies aimed at alleviating disease burden.

Oligodendroglioma is genetically defined by mutations in isocitrate dehydrogenase 1 or 2 (IDH1/IDH2) and 1p/19q codeletion. We previously showed that in IDH1-mutant oligodendroglioma, the oncometabolite D-2-hydroxyglutarate biases the sphingosine-1-phosphate–to–ceramide rheostat toward ceramides. Taking advantage of this intrinsic metabolic vulnerability, we investigated whether further elevating ceramide levels through inhibition of acid ceramidase could exacerbate this imbalance and promote apoptotic cell death.Analysis of patient datasets demonstrated that acid ceramidase is expressed at higher levels in both low- and high-grade gliomas compared with normal tissue. Pharmacologic inhibition of acid ceramidase with SABRAC preferentially reduced viability in human IDH1-mutant oligodendroglioma cell lines. In these sensitive models, acid ceramidase inhibition markedly increased ceramide levels and induced coordinated sphingolipid remodeling. Subcellular imaging using a fluorescent ceramide analogue demonstrated increased ceramide localization to lysosomes and mitochondria following acid ceramidase inhibition. This was accompanied by cytochrome c redistribution, executioner caspase activation, and caspase-dependent apoptotic cell death, consistent with engagement of intrinsic mitochondrial apoptosis. Transcriptomic and biochemical analyses further revealed activation of endoplasmic reticulum stress and unfolded protein response signaling, including PERK- and IRE1α-associated programs, suggesting coordinated multi-organelle stress responses under sustained ceramide elevation. These mechanistic effects translated into a survival benefit in oligodendroglioma xenograft-bearing mice.Together, these findings suggest that IDH1-mutant oligodendroglioma harbors a pre-existing heightened sensitivity to ceramide stress and identify acid ceramidase as a therapeutically actionable target in this disease.

Endoplasmic reticulum-plasma membrane contact sites (ER-PM CS) are central hubs that coordinate lipid metabolism, membrane remodelling, calcium signalling and stress responses in plant cells. This review summarizes current knowledge on the molecular architecture and functions of ER-PM CS, with emphasis on the three tether families (synaptotagmins/SYTs, multiple-C2-domain and transmembrane region proteins/MCTPs, and VAMP-associated protein 27/VAP27 proteins) and the lipid-transfer proteins (SMP-domain proteins and oxysterol-binding protein-related/ORPs) described to date. SYTs and MCTPs use C2 domains to read PM phosphoinositides and Ca2+ signals to dynamically modulate tethering, while VAP27s scaffold multimeric complexes via MSP-FFAT interactions and link the ER to the cytoskeleton. Lipid transfer at ER-PM CS sustain the phosphatidylinositol (PI) cycle and prevents accumulation of cone-shaped lipids such as diacylglycerol (DAG) at the PM. In plants, SYT1/SYT3 form a module with diacylglycerol kinases (DGKs) to clear DAG from the PM and to channel DAG into metabolism. ORP family members function as PI/PS (and sterol) exchangers and integrate contact-site lipid exchange with signalling and autophagy. ER-PM CS also intersect with endocytosis, autophagosome biogenesis, plasmodesmata function and unfolded protein response signalling, underlining their multi-functional roles in cellular homeostasis and stress adaptation.

During ischemia, endothelial cell integrity is compromised, as a consequence, blood barrier homeostasis is disrupted. Therefore, the structural and functional preservation of endothelial cells is paramount when trying to improve outcomes after ischemic injury. Endoplasmic reticulum (ER) stress is increasingly recognized as a key player in ischemic injury through unfolded protein response (UPR) signalling, and its crosstalk with mitochondrial death pathways. This study provides a cost-effective and straightforward method to delve into the relationship between ER stress and ischemia in human microvascular endothelial cells-1 (HMEC-1). HMEC-1 was exposed to 8 h of oxygen–glucose deprivation (OGD) in glucose-free medium with rapidly induced hypoxia. Hypoxia, oxygen consumption, cell viability, apoptosis, and ER stress markers (BiP/GRP78, PERK, ATF6, IRE1/XBP1s, CHOP) were assessed by RT-qPCR and Western blot. Cell viability decreased by approximately 33% following OGD, while CHOP expression increased ~4-fold, indicating significant ER stress induction. The model enables quantification of metabolic stress (OCR), as well as evaluation of viability loss, membrane integrity, apoptotic commitment, and discrimination between ER stress resolution versus maladaptation. Overall, GasPak EZ Pouch Systems provide a reproducible and practical in vitro platform to study ischemic injury down to the mechanistic details of ER-mitochondria signalling. They give the opportunity to evaluate therapeutic approaches that target ER homeostasis to limit apoptosis and/or recovery of metabolic function after ischemia. This method could allow rapid screening of ER stress-modulating interventions aimed at preserving endothelial barrier function, in various ischemic contexts.

Endoplasmic reticulum stress and the unfolded protein response in ischemic nephropathy: Pathogenic mechanisms and emerging therapeutic strategies.

Ionizing radiation elicits complex cellular responses that are influenced not only by total dose but also by the rate at which the dose is delivered. Understanding how dose rate modulates molecular outcomes is important for accurate risk assessment. In this study, we apply an integrative multi-omics approach combining transcriptomic and proteomic profiling while adjusting for covariates to investigate how differential dose rates of ionizing radiation alter gene and protein expression in human lymphocytes. Particular emphasis is placed on identifying dose-rate-specific alterations in key molecular pathways. Peripheral blood from 14 healthy donors (8 males, 6 females) was irradiatedex vivowith x-rays at 0.05 Gy min-1(DR1) and 1.0 Gy min-1(DR2) across a dose range from 0 to 6 Gy. Gene expression was assessed using TempO-Seq™, and relative protein abundance was determined by mass spectrometry. Differential expression analysis was conducted using edgeR and limma, adjusting for sex, age, and leukocyte counts (false discovery rate < 0.05). Multi-omics integration was performed using regularised canonical correlation analysis (rCCA) implemented in mixOmics, followed by Reactome pathway enrichment analysis. We identified 2477 and 2612 differentially expressed genes at DR1 and DR2, respectively, and 368 and 386 differentially expressed proteins. To assess dose discrimination, we examined sample separation in the space defined by the average canonical variates from transcriptomic and proteomic datasets using rCCA. Covariate adjustment improved dose discrimination, particularly above 0.5 Gy. Using a correlation cut-off threshold of 0.5 in rCCA, 212 (DR1) and 276 (DR2) highly correlated gene-protein pairs were identified. DR2 exposure was associated with stronger enrichment of stress-related pathways, including unfolded protein response, senescence and oncogenic kinase signalling. In contrast, DR1 induced enrichment of pathways associated with immune engagement, including antigen presentation. At both dose rates, transcriptomic changes highlighted upstream regulatory processes (chromatin modelling) and proteomic changes captured downstream functional pathways such as immune activity and apoptosis. The multi-omics approach with covariate adjustment revealed key radiation-responsive pathways and dose-rate-dependent molecular differences, highlighting the value of integrating transcriptomic and proteomic data to better understand radiation effects.

Glaucoma represents a group of diseases where the unifying theme is the progressive degeneration of retinal ganglion cells (RGCs), causing irreversible vision loss. Mutations in the myocilin (MYOC) gene represent one of the most common genetic factors associated with primary open-angle glaucoma (POAG). However, the mechanism underlying MYOC mutation-associated POAG is poorly understood. Here, using human disease modeling of MYOC mutation (A445V)-dependent POAG, which is usually without ocular hypertension, we have tested a hypothesis that human RGCs (hRGCs) are the target of the mutant protein, making them vulnerable to degenerative changes. Examination of hRGCs generated from MYOCA445V POAG patient-specific induced pluripotent stem cells (iPSCs) revealed that their differentiation is adversely affected, compared to those generated from isogenic control iPSCs. Retinal ganglion cells regulatory and axon growth and guidance gene expression is decreased in patient-specific hRGCs vs isogenic controls. Consequently, the former display immature neurites and their ability to form synapses with the target cells and regenerate are compromised. Furthermore, they display immature networking physiology compared to isogenic controls. The pathological burden of the mutant protein is reflected in their preferential retention in the endoplasmic reticulum (ER) of patient-specific hRGCs, activating the unfolded protein response (UPR) toward mutation-associated developmental phenotype. Furthermore, we demonstrate that REDD1, a stress-induced factor, is a mechanistic link between the MYOCA445V-activated UPR axis and inhibited mTOR signaling, a critical regulator of RGC development and function. Ours is the first demonstration of MYOC mutation-dependent hRGC phenotype and posits a mechanism for hRGC susceptibility toward degeneration independent of ocular hypertension.

The endoplasmic reticulum (ER) is a central hub of cellular proteostasis, coordinating protein folding, lipid metabolism, calcium signaling, and inter-organelle communication. Disruptions in ER function activate the unfolded protein response (UPR), an evolutionarily conserved signaling network mediated by PERK, IRE1α, and ATF6. Initially viewed primarily as a stress-mitigating mechanism, the UPR is now recognized as a central coordinator of diverse cellular stress-response pathways. This review focuses on mechanistic insights into UPR signaling, with particular emphasis on its crosstalk with oxidative stress regulation, mitochondrial function and mitochondria-ER contact sites, autophagy, inflammatory signaling, and metabolic sensing. The analysis integrates evidence from biochemical and structural studies, genetic and pharmacological perturbation models, and selected in vivo investigations from PubMed and Google Scholar between 2000 and 2025, focusing on mechanistic, experimental and translational studies addressing UPR signaling and ER stress. Together, these studies demonstrate how transient UPR activation promotes cellular adaptation through coordinated transcriptional, translational, and organelle-specific responses. We further discuss how sustained or unresolved ER stress alters UPR outputs, shifting signaling toward maladaptive outcomes such as mitochondrial dysfunction, dysregulated autophagy, oxidative imbalance, and apoptosis. By placing the UPR within a network of interconnected stress pathways, this work provides a framework for understanding how ER proteostasis is linked to cell fate decisions under stress.

Ewing sarcoma (ES) is a rare and aggressive pediatric malignancy with limited therapeutic options, particularly for relapsed or refractory cases, highlighting the urgent need for innovative treatment strategies. In this study, we identify endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) as critical therapeutic vulnerabilities in ES and introduce 4-(heptyloxy)phenol (AC-45594) as a novel small-molecule agent that exploits these stress pathways. AC-45594 selectively inhibited the growth of ES cells among thirteen cancer and six non-cancerous cell lines, demonstrating marked tumor specificity. Structure-activity relationship studies revealed that both the phenolic hydroxyl group and an optimal alkoxy chain length (7-9 carbon atoms) are essential for its activity. Mechanistically, AC-45594 induces ERS, activates UPR, and drives a shift from adaptive to terminal stress signaling, culminating in apoptosis of ES cells. Proteomic and gene expression analyses further supported selective activation of proapoptotic UPR signaling. These findings establish ERS and UPR as actionable targets in ES and position AC-45594 as a first-in-class compound capable of selectively inducing stress-driven cell death. This work lays the foundation for a new class of therapeutics targeting maladaptive stress responses in pediatric sarcomas and potentially other hard-to-treat cancers.

The endoplasmic reticulum (ER) responds to stimuli that disrupts its homeostasis by activating a signalling network known as unfolded protein response (UPR), that restores cellular balance and determines cell fate through three key sensors: inositol-requiring enzyme 1α (IRE1α), activating transcription factor 6 (ATF6), and protein kinase RNA-like ER kinase (PERK). Emerging evidence suggests that UPR regulates the expression of numerous long non-coding RNAs (lncRNAs), which play critical roles in maintaining ER homeostasis. Here we show that expression of lncRNA H19 is downregulated in response to ER stress in (MCF7, T47D and 293T) cells. Using genetic and pharmacological approaches, we demonstrate that H19 downregulation is primarily mediated by the PERK arm of the UPR. Specifically, knockdown or chemical inhibition of PERK compromised the ER stress-mediated H19 repression, while PERK activation significantly reduced H19 expression. H19 overexpression promotes the optimal activation of ATF6 and PERK pathways, while it attenuates the signalling by IRE1-XBP1 axis of the UPR. Furthermore, in triple-negative breast cancer (TNBC) cells MDA-MB-231, ectopic H19 provided resistance to ER stress-induced apoptosis. Bioinformatic analyses across multiple breast cancer cohorts revealed that high H19 expression was associated with poor prognosis, particularly in basal-like subtypes. Collectively, our findings show that H19 is downregulated during UPR in a PERK-dependent manner, where H19 in turn modulates UPR signalling and cell fate during conditions of ER stress.

The unfolded protein response (UPR) serves as a crucial regulatory mechanism that enables eukaryotic cells to mitigate endoplasmic reticulum (ER) stress and plays a significant role in plant antiviral immunity. In this study, we show that V2 protein encoded by the tomato yellow leaf curl virus (TYLCV) induces severe necrotic symptoms in Nicotiana benthamiana and tomato plants. V2 activates the host UPR, and this activation promotes TYLCV infection. Furthermore, we demonstrate that V2 directly interacts with NbFKBP13, a rate-limiting enzyme in protein folding, and inhibits its enzymatic activity. Genetic analysis revealed that NbFKBP13 significantly attenuates V2-induced UPR activation and cell death while enhancing N. benthamiana resistance against TYLCV infection. Similarly, V2 interacts with SlFKBP13, the tomato homolog of NbFKBP13, and SlFKBP13 improves tomato resistance to TYLCV infection. Moreover, both TYLCV infection and V2 expression induce autophagy, a process in which NbFKBP13 plays a crucial role. Notably, the activation of autophagy inhibits TYLCV infection. Our results unveil a molecular mechanism through which the geminivirus V2 protein manipulates the host UPR to facilitate viral infection. These findings significantly advance our understanding of the evolutionary arms race between plants and viruses.

PERK-eIF2α activation by avian reticuloendotheliosis virus: a dual strategy to suppress apoptosis and aggravate immunosuppression for enhanced replication.

To summarize the role of endoplasmic reticulum stress (ERS) in the pathogenesis of diabetic retinopathy (DR) and evaluate potential ERS-targeted interventions. This review analyzes recent preclinical and clinical studies focusing on the molecular mechanisms of ERS and its impact on retinal inflammation, oxidative stress, and angiogenesis in DR. ERS, triggered by hyperglycemia-induced oxidative stress and glucotoxicity, activates the unfolded protein response (UPR) via inositol-requiring enzyme 1 (IRE1), PKR-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) pathways. While initially protective, prolonged ERS leads to apoptosis, chronic inflammation, and neovascularization. Key downstream mediators include C/EBP homologous protein (CHOP), X-box binding protein 1 (XBP1), and activating transcription factor 4 (ATF4). ERS inhibitors such as 4-phenylbutyric acid and tauroursodeoxycholic acid, along with selective modulators of UPR signaling, have shown neuroprotective and anti-inflammatory effects in DR models. Combination therapies integrating antioxidants and anti-inflammatory agents demonstrate synergistic efficacy. However, clinical translation remains limited by delivery barriers and incomplete understanding of UPR-specific actions in the human retina. Targeting ERS presents a promising therapeutic strategy for DR, with the potential to preserve vision and improve outcomes for diabetic patients. Future research should focus on elucidating the precise molecular pathways and developing targeted, personalized ERS-modulating therapies.

Excessive glutamate release during excitotoxic events such as stroke and neurodegeneration leads to elevated mitochondrial reactive oxygen species (ROS) production and mitochondrial membrane depolarization, contributing to dysfunction of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and subsequent endoplasmic reticulum (ER) stress. SERCA is critical for maintaining ER Ca2+ homeostasis, and its impairment exacerbates ER stress and neuronal excitotoxicity. In this study, we investigated the neuroprotective potential of CDN1163 (4-(1-methylethoxy)-N-(2-methyl-8-quinolinyl)-benzamide), a small-molecule SERCA activator, in an in vitro model of glutamate-induced toxicity using N2a cells. Glutamate exposure markedly reduced cell viability and induced apoptosis, as evidenced by increased caspase-3 and Bax expression along with suppression of the antiapoptotic protein Bcl-2. These cytotoxic effects were accompanied by excessive intracellular and mitochondrial ROS generation and dissipation of the mitochondrial membrane potential (ΔΨm), indicating mitochondrial dysfunction. Glutamate further disrupted mitochondrial quality control by impairing mitophagy initiation, reflected by reduced PINK1 and Parkin expression and altered LC3-II and phospho-p62 levels. This mitochondrial impairment coincided with pronounced ER stress, characterized by activation of unfolded protein response signaling pathways, including increased expression of BiP, p-IRE1α, XBP 1s, p-PERK, p-eIF2α, ATF4, CHOP, and ATF6, together with downregulation of SERCA1a and SERCA2b, leading to ER Ca2+ dyshomeostasis. Treatment with CDN1163 significantly reversed glutamate-induced cytotoxicity by restoring cell viability, suppressing apoptosis, reducing mitochondrial and cellular ROS, stabilizing mitochondrial membrane potential, reactivating mitophagy, and alleviating ER stress through restoration of SERCA expression and ER Ca2+ homeostasis. Collectively, these findings demonstrate that CDN1163 confers neuroprotection against glutamate-induced excitotoxic injury by targeting interconnected mitochondrial and ER stress pathways, highlighting its therapeutic potential in excitotoxic neurodegenerative conditions.