Endoplasmic reticulum stress and unfolded protein response in cardiovascular diseases

Magnesium-assisted hydrogen improves isoproterenol-induced heart failure

Heart failure (HF) is a leading cause of mortality among patients with cardiovascular disease and is often associated with myocardial apoptosis and endoplasmic reticulum stress (ERS). While hydrogen has demonstrated potential in reducing oxidative stress and ERS, recent evidence suggests that magnesium may aid in hydrogen release within the body, further enhancing these protective effects. This study aimed to investigate the cardioprotective effects of magnesium in reducing apoptosis and ERS through hydrogen release in a rat model of isoproterenol (ISO)-induced HF. Magnesium was administered orally to ISO-induced HF rats, which improved cardiac function, reduced myocardial fibrosis and cardiac hypertrophy, and lowered the plasma levels of creatine kinase-MB, cardiac troponin-I, and N-terminal B-type natriuretic peptide precursor in ISO-induced HF rats. It also inhibited cardiomyocyte apoptosis by upregulating B-cell lymphoma-2, downregulating Bcl-2-associated X protein, and suppressing ERS markers (glucose-related protein 78, activating transcription factor 4, and C/EBP-homologous protein). Magnesium also elevated hydrogen levels in blood, plasma, and cardiac tissue, as well as in artificial gastric juice and pure water, where hydrogen release lasted for at least four hours. Additionally, complementary in vitro experiments were conducted using H9C2 cardiomyocyte injury models, with hydrogen-rich culture medium as the intervention. Hydrogen-rich culture medium improved the survival and proliferation of ISO-treated H9C2 cells, reduced the cell surface area, inhibited apoptosis, and downregulated ERS pathway proteins. However, the protective effects of hydrogen were negated by tunicamycin (an inducer of ERS) in H9C2 cells. In conclusion, magnesium exerts significant cardioprotection by mitigating ERS and apoptosis through hydrogen release effects in ISO-induced HF.

Pharmacological landscape of endoplasmic reticulum stress: Uncovering therapeutic avenues for metabolic diseases

The endoplasmic reticulum (ER) plays a fundamental role in maintaining cellular homeostasis by ensuring proper protein folding, lipid metabolism, and calcium regulation. However, disruptions to ER function, known as ER stress, activate the unfolded protein response (UPR) to restore balance. Chronic or unresolved ER stress contributes to metabolic dysfunctions, including insulin resistance, non-alcoholic fatty liver disease (NAFLD), and neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. Recent studies have also highlighted the importance of mitochondria-ER contact sites (MERCs) and ER-associated inflammation in disease progression. This review explores the current pharmacological landscape targeting ER stress, focusing on therapeutic strategies for rare metabolic and neurodegenerative diseases. It examines small molecules such as tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA), repurposed drugs like 17-AAG (17-N-allylamino-17demethoxygeldanamycin (tanespimycin)) and berberine, and phytochemicals such as resveratrol and hesperidin. Additionally, it discusses emerging therapeutic areas, including soluble epoxide hydrolase (sEH) inhibitors for metabolic disorders and MERCs modulation for neurological diseases. The review emphasizes challenges in translating these therapies to clinical applications, such as toxicity, off-target effects, limited bioavailability, and the lack of large-scale randomized controlled trials (RCTs). It also highlights the potential of personalized medicine approaches and pharmacogenomics in optimizing ER stress-targeting therapies.

Endoplasmic reticulum stress-autophagy axis is involved in copper-induced ovarian ferroptosis

Copper (Cu) contamination has emerged a global public health problem due to the extensive use of Cu in industrial production and daily life. Reproductive damage resulting from Cu exposure has been particularly evident. Wilson's disease (WD) is a recessive genetic disease characterized by impaired Cu metabolism. Female WD patients have often been associated with reproductive impairment. Ferroptosis, a form of iron-dependent regulated cell death, has been identified as being caused by massive lipid peroxide-mediated membrane damage. However, it remains unclear whether ferroptosis is associated with Cu-induced ovarian damage. In this study, the role of ferroptosis in ovarian damage induced by Cu accumulation and its underlying mechanisms were examined through both in vivo and in vitro experiments. The findings indicated that excessive Cu deposition in the ovaries could lead to follicular atresia and ovulation dysfunction, and trigger ferroptosis in ovarian and granulosa cells (GCs). The mechanism may be related to endoplasmic reticulum (ER) stress mediated by the protein kinase RNA-like ER kinase (PERK) pathway, and hyperactivation of autophagy. In addition, Cu-induced autophagy in GCs was found to increase intracellular iron levels via the ferritinophagy pathway, thereby inducing ferroptosis. We also found that mitochondrial reactive oxygen species (MitoROS) may be an onstream facilitator of Cu-induced ferroptosis via activation of the ER stress-autophagy pathway. Our findings suggested that ferroptosis is associated with Cu-induced ovarian damage and is regulated by the MitoROS-ER stress-autophagy axes. These results might provide insights for developing treatment for WD and other diseases related to Cu exposure.

Therapeutic potential of natural flavonoids in atherosclerosis through endothelium-protective mechanisms: An update

Atherosclerosis and its associated cardiovascular complications remain significant global public health challenges, underscoring the urgent need for effective therapeutic strategies. Endothelial cells are critical for maintaining vascular health and homeostasis, and their dysfunction is a key contributor to the initiation and progression of atherosclerosis. Targeting endothelial dysfunction has, therefore, emerged as a promising approach for the prevention and management of atherosclerosis. Among natural products, flavonoids, a diverse class of plant-derived phenolic compounds, have garnered significant attention for their anti-atherosclerotic properties. A growing body of evidence demonstrates that flavonoids can mitigate endothelial dysfunction, highlighting their potential as endothelial dysfunction-targeted therapeutics for atherosclerosis. In this review, we summarize current knowledge on the roles of natural flavonoids in modulating various aspects of endothelial dysfunction and their therapeutic effects on atherosclerosis, focusing on the underlying molecular mechanisms. We also discuss the challenges and future prospects of translating natural flavonoids into clinical applications for cardiovascular medicine. This review aims to provide critical insights to advance the development of novel endothelium-protective pharmacotherapies for atherosclerosis.

Specialized Pro-Resolving Mediators as Emerging Players in Cardioprotection: From Inflammation Resolution to Therapeutic Potential

AIM

Timely myocardial reperfusion is essential for restoring blood flow to post-ischemic tissue, thereby reducing cardiac injury and limiting infarct size. However, this process can paradoxically result in additional, irreversible myocardial damage, known as myocardial ischemia-reperfusion injury (MIRI). The goal of this review is to explore the role of specialized pro-resolving mediators (SPMs) in atherosclerosis and MIRI, and to assess the therapeutic potential of targeting inflammation resolution in these cardiovascular conditions.

METHODS

This review summarizes current preclinical and clinical evidence on the involvement of SPMs in the pathogenesis of atherosclerosis and MIRI, acknowledging that several cellular and molecular aspects of their mechanisms of action remain to be fully elucidated.

RESULTS

MIRI is a complex phenomenon in which inflammation, initially triggered during ischemia and further amplified upon reperfusion, plays a central role in its pathogenesis. Various cellular and molecular players mediate the initial pro-inflammatory response and the subsequent anti-inflammatory reparative phase following acute myocardial infarction (AMI), contributing both to ischemia- and reperfusion-induced damage as well as to the healing process. SPMs have emerged as key endogenous immunoresolvents with potent anti-inflammatory, antioxidant, and pro-resolving properties that contribute to limit excessive acute inflammation and promote tissue repair. While dysregulated SPM-related signaling has been linked to various cardiovascular diseases (CVD), their precise role in AMI and MIRI remains incompletely understood.

CONCLUSION

Targeting inflammation resolution may represent a promising therapeutic strategy for mitigating atheroprogression and addressing a complex condition such as MIRI.

Endoplasmic reticulum stress regulates swainsonine-induced the autophagy in renal tubular epithelial cells through UPR signaling pathway

Swainsonine (SW), the primary toxic component of locoweed, induces toxic response in grazing livestock. The swainsonine induced toxicity is characterized by symptoms including head tremors, ataxia, and limb paralysis. The mechanisms of the toxicity remained to be investigated. The unfolded protein response (UPR) plays a key role in alleviating endoplasmic reticulum stress (ERS) by reducing protein synthesis and promoting the degradation of misfolded proteins. ERS is closely associated with both the UPR and autophagy activation. However, the involvement of the UPR signaling pathway in SW-induced ERS and autophagy remains unclear. In this study, we demonstrate that SW up-regulates the expression of GRP78, XBP1s, LC3-II/I, and ATG5 in both in vitro and in vivo models, suggesting activation of ERS, UPR, and autophagy. To investigate the molecular mechanisms by which the UPR regulates autophagy under ERS in primary rat renal tubular epithelial cells (RTECs), we observed that inhibiting PERK led to increased levels of p62. Inhibition of ATF6 significantly reduced the up-regulation of LC3-II/I, p62, and ATG5. Furthermore, inhibiting IRE1α significantly decreased the expression of LC3-II/I and p62. These findings suggest that PERK and ATF6 regulate autophagy mainly by modulating the expression of autophagy-related genes, while IRE1α likely regulates these genes through the IRE1α-XBP1 pathway. Additionally, autophagy is directly regulated through the IRE1α-JNK signaling pathway.

Akt mitigates ER stress-instigated cardiac dysfunction via regulation of ferroptosis and mitochondrial integrity in a DHODH-dependent manner

ER stress evokes various types of cell death and myocardial dysfunction. This study aimed to discern the involvement of ferroptosis in chronic Akt activation-offered benefit, if any, against ER stress-triggered cardiac remodeling and contractile anomalies. Cardiac-selective expression of active mutant of Akt (AktOE) and wild-type (WT) mice were challenged with the ER stress instigator tunicamycin (1 mg/kg, 48 h) prior to assessment of cardiac morphology and function. Tunicamycin insult prompted cardiac remodeling (interstitial fibrosis), deranged echocardiographic (higher LVESD, dropped ejection fraction and fractional shortening), cardiomyocyte mechanical and intracellular Ca2+ features alongside mitochondrial injury (collapsed mitochondrial membrane potential and ultrastructural change), oxidative stress, compromised Akt-GSK3β signaling, ER stress (upregulated GRP78 and Gadd153), carbonyl formation, apoptosis and ferroptosis (decreased GPX4, SLC7A11). Intriguingly, tunicamycin-evoked anomalies (except GRP78 and Gadd153) were abrogated by Akt activation. Chronic Akt activation negated tunicamycin-induced downregulation of ferric flavin enzyme dihydroorotate dehydrogenase (DHODH), which catalyzes the fourth step of pyrimidine ab initio biosynthesis, and conversion of dihydroorotic acid to orotate. ER stress-induced myocardial anomalies were reversed by the newly identified PI3K activator triptolide, DHODH activator menaquinone-4 and pyrimidine booster coenzyme Q. In vitro experiment revealed that Akt activation- or triptolide-evoked beneficial responses against tunicamycin-induced cardiomyocyte anomalies were cancelled off by DHODH inhibitor BAY2402234 or ferroptosis inducer erastin. These findings support that chronic Akt activation rescues ER stress-evoked myocardial derangements through DHODH-dependent control of ferroptosis and mitochondrial homeostasis.

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

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

PDZD8 Dysregulation Mediates RVLM Neuronal Hyperexcitation Via Activation of Ca2+-Calpain-2 Signaling in Stress-Induced Hypertension

Neuronal hyperexcitation in the rostral ventrolateral medulla (RVLM) is crucial in the pathogenesis of stress-induced hypertension (SIH). PDZD8 connects endoplasmic reticulum (ER) to mitochondria, and is involved in SIH through regulating RVLM neuronal mitochondrial physiological function. However, the underlying mechanisms of the PDZD8 dysregulation-mediated mitochondrial dysfunction of RVLM neurons, affecting neuronal excitability during SIH, are not fully clarified. An SIH rat model was established by administering intermittent electric foot shocks combined with noise exposure for 2 h twice daily over a period of 15 days. The impacts of PDZD8 on regulating RVLM neuronal ER stress, mitochondrial function, apoptosis, and blood pressure (BP) of SIH rats, along with the related signaling pathway, were explored through using in-vivo and in-vitro techniques like RVLM microinjection, Western blot, flow cytometry, and immunofluorescence. We demonstrated that the ratio of c-Fos-positive tyrosine hydroxylase (TH) neurons, renal sympathetic nerve activity (RSNA), plasma norepinephrine (NE) levels, BP, and heart rate (HR) increased in SIH rats. The activated neuronal ER stress, impaired mitochondrial function, and apoptosis were observed in the RVLM of SIH rats and PDZD8-deficient N2a cells. ER stress inhibitor (4-phenylbutyric acid, 4-PBA) administration effectively alleviated PDZD8 dysregulation-induced mitochondrial dysfunction and apoptosis. Mechanistically, PDZD8 negatively regulated Calpain-2 (CAPN2) expression through modulating cytoplasmic Ca2+ levels. In vitro, CAPN2 inhibition rescued PDZD8 deficiency-induced ER stress, mitochondrial dysfunction, and apoptosis. In vivo, PDZD8 upregulation in the RVLM of SIH rats attenuated neuronal ER stress, mitochondrial dysfunction, and apoptosis, thus reducing RVLM neuronal excitability, RSNA, plasma NE, BP, and HR. These effects were blocked by CAPN2 overexpression. Overall, this study revealed that PDZD8 dysregulation induced RVLM neuronal ER stress, mitochondrial damage, and apoptosis by activating the Ca2+-CAPN2 axis, playing a crucial pathological role in SIH progression.

Tuning SBDs as Endoplasmic Reticulum Self-Targeting Fluorophores and Its Application for Zn2+ Tracking in ER Stress

The emerging endoplasmic recticulum (ER) crosstalk system demands a more reliable approach for ER-targeting fluorophores to explore ER-associated biochemical species and events. Providing the aromatic sulfonamides' affinity to ATP-sensitive potassium channel protein localized mainly on ER membrane, the sulfonamide fluorophore 4-amino-7-sulfamoylbenzoxadiazole (SBD) was modified to construct ER self-targeting fluorophores without any additional targeting group by alternating the N-substituent structure and numbers of its 4-amino and 7-sulfamoyl groups. The results revealed that a ClogP value over 3.0 endowed those SBDs the ER self-targetability effectively. This provides a strategy to devise an ER-targeting probe by simply modifying the 4-amino group of SBDs as a sensing moiety to make the probe CLogP over 3.0 despite the CLogP value of parent SBDs, and two ER-targeting Zn2+ probes ER-SBD-Zn1 and ER-SBD-Zn2 were obtained following this idea. Moreover, ER Zn2+ tracking with ER-SBD-Zn1 disclosed for the first time tunicamycin concentration-dependent ER Zn2+ fluctuation behavior during ER stress induction.

Targeting mitochondria with natural polyphenols for treating Neurodegenerative Diseases: a comprehensive scoping review from oxidative stress perspective

Neurodegenerative diseases are a class of conditions with widespread detrimental impacts, currently lacking effective therapeutic drugs. Recent studies have identified mitochondrial dysfunction and the resultant oxidative stress as crucial contributors to the pathogenesis of neurodegenerative diseases. Polyphenols, naturally occurring compounds with inherent antioxidant properties, have demonstrated the potential to target mitochondria and mitigate oxidative stress. This therapeutic potential has garnered significant attention in recent years. Investigating the mitochondrial targeting capacity of polyphenols, their role in functional regulation, and their ability to modulate oxidative stress, along with exploring novel technologies and strategies for modifying polyphenol compounds and their formulations, holds promise for providing new avenues for the treatment of neurodegenerative diseases.

Lingguizhugan decoction ameliorates renal injury secondary to heart failure by improving pyroptosis through TLR4/NF-KB/IRE1α pathway

BACKGROUND

Chronic heart failure (CHF) and chronic kidney disease (CKD) mutually promote the onset and progression of each other. Renal injury caused by heart failure currently lacks effective treatments. Previous studies have shown that Linggui Zhugan decoction (LGZGD) can significantly improve heart failure (HF) and cardiac remodeling, and has been reported to have renal protective effects. However, the effects and mechanisms of LGZGD in heart failure-induced renal injury remain unclear.

PURPOSE

Based on these findings, this study aims to investigate the effects and underlying mechanisms of LGZGD on renal injury secondary to HF.

STUDY DESIGN

We used network pharmacology to predict potential targets of LGZGD in the treatment of cardiorenal syndrome (CRS). An in vivo model of CRS with right heart failure and venous congestion was established by a single intraperitoneal injection of monocrotaline (MCT). TNF-α-stimulated NRK52E cells were used as an in vitro model. We validated the effects of LGZGD in both in vivo and in vitro experiments,. Additionally, molecular docking with the components of LGZGD identified previously was performed to predict potential targets of action.

RESULTS

LGZGD significantly improved heart and kidney function as well as renal histopathological changes in CRS rats. It inhibited the TLR4/NF-κB/IRE1α pathway in the kidneys and downregulated the expression of pyroptosis-related proteins (NLRP3, GSDMD, Caspase-1, IL-18, and IL-1β). Both LGZGD-containing serum and the TLR4 inhibitor (TAK-242) significantly reduced apoptosis in TNF-α-stimulated NRK52E cells and decreased the levels of TLR4/NF-κB/IRE1α pathway signaling and pyroptosis-related proteins. Molecular docking suggested that neoliquiritin (CID_51666248), enoxolon (CID_10114), and liquiritin (CID_503737) could stably bind to key targets such as IRE1α, caspase-1, and NF-κB.

CONCLUSION

This study demonstrated for the first time that LGZGD might ameliorate renal injury secondary to HF by improving pyroptosis through the TLR4/NF-κB/IRE1α pathway, which may provide valuable insights for future research in the treatment of CRS.

Safranal ameliorates atherosclerosis progression partly via repressing PI3K/Akt and NF-κB signaling pathways in ApoE (-/-) mice

Atherosclerosis (AS) remains the main cause of vascular diseases. This study reveals the effects of safranal and underlying mechanisms in RAW264.7 macrophages under AS context, which is hoped to facilitate its clinical application. Safranal reduced AS progression in ApoE (-/-) mice, and it also increased the serum level of HDL-C and decreased the levels of TG, TC, and LDL-C as well as ALT and AST. Besides, safranal repressed the pathophysiological processes of OS (downregulated levels of ROS and MDA and upregulated biosynthesis of GSH), ERS (decreased protein levels of activating transcription factor 6, X-Box Binding Protein 1, and glucose-regulated protein, 78 kDa), and inflammation (downregulated serum levels of TNF-α, IL-1β, and IL-6) in vivo. Mechanistically, safranal repressed PI3K/Akt and NF-κB signaling pathways in vivo. On the cellular level, safranal treatment relieved the uptake of ox-LDL, and decreased contents of TG, TC, and LDL-C while increasing HDL-C level in ox-LDL-treated RAW264.7 macrophages. It also reduced the molecular indexes of pathophysiological processes (OS, ESR, and release of inflammatory mediators) in ox-LDL-exposed RAW264.7 macrophages. Notably, safranal treatment also impaired PI3K/Akt and NF-κB signaling pathways in ox-LDL-exposed RAW264.7 macrophages. Additionally, the PI3K agonist 740Y-P notably reversed the in vitro inhibitory effects of safranal on lipid deposition, productions of TC and TNF-α, and protein levels of molecules of PI3K/Akt and NF-κB signaling pathways. Safranal exerts anti-AS effects via repressing OS, ERS, and inflammation in ApoE (-/-) mice, and it also negatively modulates PI3K/Akt and NF-κB signaling pathways in RAW264.7 macrophages.

QRICH1 regulates ATF6 transcription to affect pathological cardiac hypertrophy progression

BACKGROUND

Many studies have shown that pathological cardiac hypertrophy is associated with active endoplasmic reticulum (ER) stress. Glutamine-rich protein 1 (QRICH1), as a transcriptional regulator, belongs to the caspase recruitment domain (CARD)-containing gene family. QRICH1 has been shown to influence the outcomes of endoplasmic reticulum stress by regulating the transcription of proteostasis-related genes. In this study, we explored the role of QRICH1 in pathological cardiac hypertrophy.

METHODS

We observed an increased expression of QRICH1 in the hearts of humans and mice with left ventricular hypertrophy (LVH). To assess the functional impact in this context, we employed gain- and loss-of-function approaches, using AAV9 injections to establish cardiac-specific QRICH1 knockdown or overexpression models in transverse aortic constriction (TAC) or isoproterenol (ISO)-induced cardiac hypertrophy.

RESULTS

Our data indicated that cardiomyocyte-specific knockdown of QRICH1 alleviated the hypertrophic phenotype in response to TAC or ISO injection. However, overexpression of QRICH1 exacerbated cardiac hypertrophy, remodeling, dysfunction, cell apoptosis, and inflammatory responses. Mechanistically, we demonstrated that ATF6 was significantly enriched by QRICH1 in cardiomyocytes treated with ISO using RNA-seq combined with CUT&TAG analysis. ChIP-qPCR and luciferase assays further confirmed that ATF6 is a target gene of QRICH1 in cardiomyocytes under growth stimulation. Knockdown of QRICH1 in cardiomyocytes blocked ISO-mediated induction of ATF6, activation of mTORC1, and cellular growth. And all of the above was restored by the overexpression of ATF6.

CONCLUSIONS

QRICH1 plays a pivotal role in cardiac hypertrophy by regulating ATF6, and QRICH1 may be a potential new therapeutic target for pathological cardiac hypertrophy.

Thioredoxin: a key factor in cold tumor formation and a promising biomarker for immunotherapy resistance in NSCLC

Immune checkpoint blockade (ICB) therapy has shown promising clinical efficacy in cancer treatment, but only a subset of patients experience significant therapeutic responses. Tumor cells respond to internal and external stresses, such as hypoxia and nutrient deprivation, by activating the unfolded protein response (UPR) in the tumor microenvironment. This response helps maintain homeostasis, promoting malignant progression, chemotherapy resistance, and immune escape. In this study, single-cell RNA sequencing (scRNA-seq) data from non-small cell lung cancer (NSCLC) patients treated with ICB revealed upregulation of thioredoxin (TXN) expression in the epithelial tissues of LUAD (lung adenocarcinoma) and LUSC (lung squamous cell carcinoma) patients with minimal pathological remission. High TXN expression was also associated with "cold tumors," characterized by a lack of T cells and low levels of chemokine receptors and immunomodulators. Experimental results showed that TXN was highly expressed in NSCLC tissues, and its knockdown significantly inhibited the proliferation and migration of A549 and SK-MES-1 cells. Furthermore, TXN knockdown enhanced T-cell-mediated cytotoxicity against these tumor cells, suggesting that TXN contributes to immune escape in NSCLC by promoting tumor cell proliferation and migration while inhibiting immune killing. Notably, TXN knockdown also upregulated CD40 expression, indicating that TXN may regulate immune escape in lung cancer through CD40 modulation.

Inner Ear Pathologies After Cochlear Implantation in Guinea Pigs: Functional, Histopathological, and Endoplasmic Reticulum Stress-Mediated Apoptosis

OBJECTIVES

Vestibular dysfunction is one of the most common complications of cochlear implantation (CI); however, the pathological changes and mechanisms underlying inner ear damage post-CI remain poorly understood. This study aimed to investigate the functional and histopathological changes in the cochlea and vestibule as well as endoplasmic reticulum (ER) stress-mediated apoptosis in guinea pigs after CI.

DESIGN

Auditory brainstem response, ice water test, and vestibular evoked myogenic potentials were used to assess cochlear and vestibular function in guinea pigs before and after CI. Histopathological analyses were conducted at various time points post-CI to observe morphological changes in the cochlea and vestibule, as well as the impact of ER stress on these tissues.

RESULTS

After CI, 10.7% (9/84) of the guinea pigs exhibited nystagmus and balance dysfunction. Auditory brainstem response thresholds increased significantly after CI, and air-conducted cervical and ocular vestibular evoked myogenic potential response rates decreased. The ice water test revealed a gradual reduction in nystagmus elicitation rates, along with decreased nystagmus frequency, prolonged latency, and shortened duration. Histopathological analysis of the cochlea revealed fibrous and osseous tissue formation in the scala tympani and a reduction in hair cells and spiral ganglion cells. In the vestibule, alterations included flattening the ampullary crista and disorganized sensory epithelial cells. Transmission electron microscopy revealed pathological changes including cytoplasmic vacuolization and chromatin uniformity in both cochlear and vestibular hair cells. ER stress was prominent in the cochlea, while no substantial stress response was observed in the vestibule.

CONCLUSIONS

Our study highlights the various effects of CI surgery on cochlear and vestibular function and morphology in guinea pigs. ER stress-mediated apoptosis may contribute to secondary cochlear damage, whereas the vestibular system demonstrates adaptive responses that preserve cellular homeostasis. These findings provide insights into potential mechanisms underlying inner ear complications post-CI.

Identification of Endoplasmic Reticulum Stress-Related Genes in Acute Myocardial Infarction: A Bioinformatics Approach with Experimental Validation

Acute myocardial infarction (AMI) continues to pose a substantial risk to human lives worldwide. Endoplasmic reticulum stress (ERS) is increasingly recognized as one of the potential mechanisms of myocardial injury following AMI. The primary goal of this study is to investigate the correlation between ERS and AMI through machine learning-based bioinformatics analysis, explore key genes, and conduct in vivo and in vitro experimental validation. We performed differential analysis and Weighted Gene Co-expression Network Analysis (WGCNA) on gene expression data from the GEO database (GSE62646). The intersection with ERS-related genes (ERSRGs) was taken to obtain AMI-ERS-related genes (MIEGs), and machine learning algorithms were further used to identify key genes (Hubs) from the MIEGs. The validation set GSE59867 was used to assess the expression levels and predictive capabilities of the Hubs for AMI. An AMI rat model was established to detect the mRNA and protein expression levels of the Hubs. The protein inhibitor of the key gene FURIN was used to treat H9C2 cells under oxygen-glucose deprivation (OGD) to explore the effects of FURIN on ERS and apoptosis. Bioinformatics analysis identified 27 MIEGs, and machine learning further determined 5 Hubs highly associated with AMI and ERS: RELA, FURIN, ERGIC3, TPP1, and BGLAP. The expression of these Hubs was significantly elevated in AMI patients within both the training and validation sets, and the area under the curve (AUC) indicated good diagnostic value. Our experiments confirmed that the mRNA levels of Furin and RelA were significantly elevated in AMI rats. Furin protein was increased in AMI rats and OGD H9C2. Furin inhibitor could alleviate OGD-induced ERS and apoptosis in H9C2. Our study demonstrates that Hubs play a pivotal role in myocardial infarction. Notably, Furin and its mediated ERS and apoptosis are significant in the pathogenesis of AMI, potentially serving as target for AMI diagnosis and treatment.

The structural and functional dynamics of BiP and Grp94: opportunities for therapeutic discovery

Binding immunoglobulin protein (BiP) and glucose-regulated protein 94 (Grp94) are endoplasmic reticulum (ER)-localized molecular chaperones that ensure proper protein folding and maintain protein homeostasis. However, overexpression of these chaperones during ER stress can contribute to disease progression in numerous pathologies. Although these chaperones represent promising therapeutic targets, their inhibition has been challenged by gaps in understanding of targetable chaperone features and their complex biology. To overcome these challenges, a new assay has been developed to selectively target BiP, and compounds that exploit subtle conformational changes of Grp94 have been designed. This review summarizes recent advances in elucidating structural and functional dynamics of BiP and Grp94. We explore leveraging this information to develop novel therapeutic interventions. Finally, given the recent advances in computing, we discuss how machine learning methods can be used to accelerate drug discovery efforts.

The perspective of modern transplant science - transplant arteriosclerosis: inspiration derived from mitochondria associated endoplasmic reticulum membrane dysfunction in arterial diseases

The mitochondria-associated endoplasmic reticulum membrane (MAM) is a crucial structure connecting mitochondria and the endoplasmic reticulum (ER), regulating intracellular calcium homeostasis, lipid metabolism, and various signaling pathways essential for arterial health. Recent studies highlight MAM's significant role in modulating vascular endothelial cells (EC) and vascular smooth muscle cells (VSMC), establishing it as a key regulator of arterial health and a contributor to vascular disease pathogenesis. Organ transplantation is the preferred treatment for end-stage organ failure, but transplant arteriosclerosis (TA) can lead to chronic transplant dysfunction, significantly impacting patient survival. TA, like other vascular diseases, features endothelial dysfunction and abnormal proliferation and migration of VSMC. Previous research on TA has focused on immune factors; the pathological and physiological changes in grafts following immune system attacks have garnered insufficient attention. For example, the potential roles of MAM in TA have not been thoroughly investigated. Investigating the relationship between MAM and TA, as well as the mechanisms behind TA progression, is essential. This review aims to outline the fundamental structure and the primary functions of MAM, summarize its key molecular regulators of vascular health, and explore future prospects for MAM in the context of TA research, providing insights for both basic research and clinical management of TA.

Activation of sigma 1 receptor attenuates doxorubicin-induced cardiotoxicity by alleviating oxidative stress, mitochondria dysfunction, ER stress-related apoptosis, and autophagy impairment

The cardiotoxic effects of doxorubicin (DOX) are a significant clinical challenge. This study explored the mechanisms underlying the cardioprotective effects of fluvoxamine (FLU) in DOX-induced cardiotoxicity. In vitro and in vivo models of DOX-induced cardiotoxicity were established using H9c2 cardiomyocytes and BALB/c mice, respectively. The cardioprotective effects of FLU were evaluated using echocardiography, electrocardiography, HE staining, myocardial injury indicators, immunohistochemical staining, immunofluorescence staining, and western blotting. Small interfering RNA (siRNA) targeting the sigma-1 receptor (Sig1R), the Sig1R inhibitor haloperidol (HALO), and the nuclear factor erythroid 2-related factor 2 inhibitor ML385 were used to verify the mechanism of FLU in H9c2 cells, and molecular docking was performed to compare the binding affinities of DOX and FLU to Sig1R. DOX treatment significantly decreased Sig1R expression, leading to cardiac dysfunction, endoplasmic reticulum stress, apoptosis, impaired autophagy, oxidative stress, and mitochondrial dysfunction. Treatment with FLU mitigated these effects. Molecular docking simulations revealed that FLU showed better binding affinity for Sig1R than DOX. Moreover, the beneficial effects of FLU in DOX-induced cardiotoxicity were reduced in the presence of HALO, ML385, or Sig1R siRNA. Our study indicates that FLU effectively reduces DOX-induced cardiotoxicity by activating Sig1R, highlighting its potential as a therapeutic agent against chemotherapy-induced cardiotoxicity.

Endoplasmic reticulum stress as a driver and therapeutic target for kidney disease

The endoplasmic reticulum (ER) has crucial roles in metabolically active cells, including protein translation, protein folding and quality control, lipid biosynthesis, and calcium homeostasis. Adverse metabolic conditions or pathogenic genetic variants that cause misfolding and accumulation of proteins within the ER of kidney cells initiate an injurious process known as ER stress that contributes to kidney disease and its cardiovascular complications. Initiation of ER stress activates the unfolded protein response (UPR), a cellular defence mechanism that functions to restore ER homeostasis. However, severe or chronic ER stress rewires the UPR to activate deleterious pathways that exacerbate inflammation, apoptosis and fibrosis, resulting in kidney injury. This insidious crosstalk between ER stress, UPR activation, oxidative stress and inflammation forms a vicious cycle that drives kidney disease and vascular damage. Furthermore, genetic variants that disrupt protein-folding mechanisms trigger ER stress, as evidenced in autosomal-dominant tubulointerstitial kidney disease and Fabry disease. Emerging therapeutic strategies that enhance protein-folding capacity and reduce the burden of ER stress have shown promising results in kidney diseases. Thus, integrating knowledge of how genetic variants cause protein misfolding and ER stress into clinical practice will enhance treatment strategies and potentially improve outcomes for various kidney diseases and their vascular complications.

Advancement in early diagnosis of polycystic ovary syndrome: biomarker-driven innovative diagnostic sensor

Polycystic ovary syndrome (PCOS) is a heterogeneous multifactorial endocrine disorder that affects one in five women around the globe. The pathology suggests a strong polygenic and epigenetic correlation, along with hormonal and metabolic dysfunction, but the exact etiology is still a mystery. The current diagnosis is mostly based on Rotterdam criteria, which resulted in a delayed diagnosis in most of the cases, leading to unbearable lifestyle complications and infertility. PCOS is not new; thus, constant efforts are made in the field of biomarker discovery and advanced diagnostic techniques. A plethora of research has enabled the identification of promising PCOS diagnostic biomarkers across hormonal, metabolic, genetic, and epigenetic domains. Not only biomarker identification, but the utilization of biosensing platforms also renders effective point-of-care diagnostic devices. Artificial intelligence also shows its power in modifying existing image-based analysis, even developing symptom-based prediction systems for the early diagnosis of this multifaceted disorder. This approach could affect the future management and treatment direction of PCOS, decreasing its severity and improving the reproductive life of women. The rationale of the current review is to identify the advancements in understanding the pathophysiology through biomarker discovery and the implementation of modern analytical techniques for the early diagnosis of PCOS.

Catechin promotes endoplasmic reticulum stress-mediated gastric cancer cell apoptosis via NOX4-induced reactive oxygen species

Catechin, a polyphenolic compound in various foods and beverages, shows strong anti-cancer effects against gastric cancer (GC) cells. This study explored the effect of catechin on GC cell apoptosis and endoplasmic reticulum (ER) stress. GC cells were treated with different catechin concentrations to assess effects on cell viability, LDH release, invasion, migration, apoptosis, intracellular calcium (Ca2⁺), ER stress markers, and reactive oxygen species (ROS). siRNA knockdown targeted GRP78, PERK, CHOP, and NOX4 to examine their roles in catechin-induced ER stress and apoptosis. Catechin treatment significantly reduced GC cell viability, increased LDH release, and induced apoptosis dose-dependently. Catechins elevated intracellular Ca2⁺ and ER stress markers. Co-treatment with thapsigargin (TG) intensified these effects, implicating ER stress in apoptosis. Knocking down GRP78, PERK, and CHOP mitigated catechin-induced apoptosis and restored viability. Additionally, catechins raised ROS levels, while co-treatment with Diphenyleneiodonium (DPI) or N-acetylcysteine (NAC) lowered ROS, cell damage, and ER stress markers. NOX4 knockdown countered catechin-induced viability loss and upregulated CHOP and cleaved caspase-3. Catechin induces apoptosis in GC cells through ER stress and ROS generation. Key mediators include GRP78, PERK, CHOP, and NOX4, suggesting potential therapeutic targets for enhancing catechin efficacy in GC treatment.

Vessel-On-A-Chip Coupled Proteomics Reveal Pressure-Overload-Induced Vascular Remodeling

Hypertension, the leading cause of cardiovascular disease and premature mortality, is characterized by increased vessel stretch and alterations in vascular smooth muscle cells (VSMCs). In this study, a vessel-on-a-chip model is developed to simulate both physiological and pathological stretch conditions alongside a mouse model of hypertension. Proteomics analysis is applied to investigate changes in VSMCs using the vessel-on-a-chip system and compared these findings with data from the mouse model. The results demonstrates that physiological stretch enhances the expression of contractile markers in VSMCs. Additionally, the chip effectively replicates cellular responses to pathological stretch and stress, including the upregulation of ERK signaling, calcium ion transport pathway, integrin signaling pathway, endoplasmic reticulum stress, toll-like receptor activation, oxidative stress, and synthesis of sphingolipids and ceramides. These findings indicate that the vessel chip successfully mimics in vivo biological events associated with hypertension. The vessel-on-a-chip system holds promise for advancing the study of vessel-related diseases and facilitating the development of novel hypertension therapeutics.

SGLT2i continuously prevents cardiac hypertrophy by reducing ferroptosis via AMPK up-regulation

Cardiac hypertrophy is an independent risk factor and prognosis indicator of heart failure. Early intervention of cardiac hypertrophy is crucial to prevent heart failure and improve patients' outcomes. Despite evidence that activation of AMPK (adenosine monophosphate-activated protein kinase) plays a protective role in cardiac hypertrophy, whether it plays a sustained role and the precise mechanism remains unexplored. We established in vivo model of cardiac hypertrophy by coarctation of rat abdominal aorta (AAC-CH model). SGLT2 inhibitor (SGLT2i) was used to activate AMPK and cardiac function was evaluated after 2, 4, 8, 12 weeks. Animals were killed, and cardiac tissue was examined for morphological changes, fibrosis, and ferroptosis. At 2 weeks, rats already had histopathological abnormalities including enlarged cardiomyocytes, cardiac fibrosis, and ferroptosis, which persisted overtime. However, these changes were remarkably prevented by the treatment of SGLT2i. Then, we established in vitro model of cardiac hypertrophy by treating H9C2 cells with isoproterenol (ISO,10 µM). Unexpectedly, mechanistic studies revealed that antagonism of AMPK aggravated oxidative stress and ferroptosis, reduced GPX4 (glutathione peroxidase 4) level, and partially abolished the anti-hypertrophic and anti-ferroptosis effects of SGLT2i in H9C2 cells. Taken together, the regulatory role between AMPK and ferroptosis was revealed for the first time in cardiac hypertrophy. SGLT2i counteracts ferroptosis by activating AMPK, providing a sustained protection against cardiac hypertrophy. This positions SGLT2i as a potential therapeutic agent for the treatment of cardiac hypertrophy. Besides, in addition to the downregulation of AMPK in hypertrophic heart tissue, its levels are also reduced in plasma, suggesting its potential to serve as a diagnostic marker for the early detection of ferroptosis and cardiac hypertrophy.

Quercetin alleviates cerebral ischemia and reperfusion injury in hyperglycemic animals by reducing endoplasmic reticulum stress through activating SIRT1

Hyperglycemia aggravates cerebral ischemic reperfusion injury (CIRI). Neuroprotective drugs that are effective in reducing CIRI in animals with normoglycemic condition are ineffective in ameliorating CIRI under hyperglycemic condition. This study investigated whether quercetin alleviates hyperglycemic CIRI by inhibiting endoplasmic reticulum stress (ERS) through modulating the SIRT1 signaling pathway. A middle cerebral artery occlusion/reperfusion (MCAO/R) model was induced in STZ-injected hyperglycemic rats. High glucose and oxygen glucose deprivation/reoxygenation (OGD/R) models were established in HT22 cells. The results demonstrated that hyperglycemia exacerbated CIRI, and quercetin pretreatment decreased the neurological deficit score and cerebral infarct volume, and alleviated neuron damage in the cortex of the penumbra in hyperglycemic MCAO/R rats, indicating that quercetin could be a candidate for treating hyperglycemic CIRI. Moreover, quercetin pretreatment reduced apoptosis, inhibited the expression of the ERS marker proteins GRP78 and ATF6, and mitigated the expression of the ERS-mediated proapoptotic protein CHOP in hyperglycemic MCAO/R rats, suggesting that quercetin alleviated hyperglycemic CIRI by inhibiting ERS and ERS-mediated apoptosis. Furthermore, quercetin upregulated Sirt1 expression in HG+OGD/R treated HT22 cells and inhibited PERK, p-eIF2α, ATF4, and CHOP expression. In contrast, the SIRT1 selective inhibitor EX-527 blocked the effect of quercetin on protein expression in the SIRT1/PERK pathway and aggravated HT22 cell injury. These findings indicate that quercetin inhibits ERS-mediated apoptosis through modulating the SIRT1 and PERK pathway. In conclusion, quercetin alleviates hyperglycemic CIRI by inhibiting ERS-mediated apoptosis through activating SIRT1 that consequently suppressed ERS signaling.

Dissection of the potential mechanism of polystyrene microplastic exposure on cardiomyocytes

Microplastics (MPs) are ubiquitous in the global biosphere, have widespread contact with humans, and increase exposure risks. Increasing evidence indicates that MPs exposure increases the risks of cardiovascular disease, however, a comprehensive exploration of the fundamental cellular mechanisms has yet to be undertaken. In this study, we used AC16 cells as a model and exposed them to 10 to 50 μg/mL of polystyrene MPs (PS-MPs), chosen based on the average daily intake and absorption of MPs by humans, to investigate their roles and mechanisms in cell injury. Proteomic analysis reveals that PS-MP-induced differentially expressed genes were enriched on endoplasmic reticulum (ER) stress and autophagy-related entries. The findings from immunofluorescence and western blotting provided further verification of the activation of ER stress by PS-MPs. Although the expression of LC3-II, a canonical autophagy marker was increased, PS-MPs inhibited autophagic flux instead of inducing autophagy. Importantly, ER stress not only contributes to PS-MPs-induced cell injury but also involved in PS-MPs-induced autophagic flux inhibition. Furthermore, the inhibition of autophagy, and the partial restoration of cell injury induced by PS-MPs was achieved through the activation of autophagy. Overall, the results reveal that activation of ER stress and inhibition of autophagic flux plays a significant role in the cell injury caused by PS-MPs in human cardiomyocytes, offering a novel perspective on the mechanism behind MPs-induced cardiomyocyte toxicity.

Risk Factors and Genetic Insights into Coronary Artery Disease-Related Sudden Cardiac Death: A Molecular Analysis of Forensic Investigation

Sudden cardiac death (SCD) is a major cause of mortality among patients with coronary artery disease (CAD). This study aimed to identify risk factors for CAD-related SCD (SCDCAD) through autopsy data and genetic screening with a particular emphasis on rare variants (minor allele frequency < 0.01). We included 241 SCDCAD cases (mean age 54.6 ± 12.8 years, 74.7% male) verified by medico-legal examination and 241 silent CAD controls (mean age 53.6 ± 15.2 years, 25.3% female) who died from severe craniocerebral trauma. Information about death characteristics was obtained from questionnaires, police reports and autopsy data. Whole-exome sequencing was performed on myocardial tissue samples. Polygenic risk score (PRS) from a previously validated model was applied and rare variant pathogenicity was predicted using in silico tools. SCDCAD victims predominantly died at night and showed higher mortality rates during summer and winter months, with more complex coronary disease. Nocturnal time (adjusted odds ratio [AOR] = 3.53, 95% CI: 2.37-5.25, p < 0.001), winter (AOR = 2.06, 95% CI: 1.33-3.20, p = 0.001), multiple vessel occlusion (AOR = 1.79, 95% CI: 1.16-2.77, p = 0.009), right coronary artery stenosis (AOR = 2.38, 95% CI: 1.54-3.68, p < 0.001) and unstable plaque (AOR = 2.17, 95% CI: 1.46-3.23, p < 0.001) were identified as risk factors of SCDCAD. The PRS score was associated with a 60% increased risk of SCDCAD (OR = 1.632 per SD, 95%CI: 1.631-1.633, p < 0.001). Genetic analysis identified MUC19 and CGN as being associated with SCDCAD. We identified both hereditary and acquired risk factors that may contribute to cardiac dysfunction and precipitate SCD in CAD patients, thereby facilitating the prevention and early recognition of high-risk individuals.

Nrf3-Mediated Mitochondrial Superoxide Promotes Cardiomyocyte Apoptosis and Impairs Cardiac Functions by Suppressing Pitx2

BACKGROUND

Myocardial infarction (MI) elicits mitochondria reactive oxygen species (ROS) production and cardiomyocyte (CM) apoptosis. Nrf3 (nuclear factor erythroid 2-related factor 3) has an established role in regulating redox signaling and tissue homeostasis. Here, we aimed to evaluate the role and mechanism of Nrf3 in injury-induced pathological cardiac remodeling.

METHODS

Global (Nrf3-KO) and CM-specific (Nrf3△CM) Nrf3 knockout mice were subjected to MI or ischemia/reperfusion injury, followed by functional and histopathological analysis. Primary neonatal mouse and rat ventricular myocytes and CMs derived from human induced pluripotent stem cells were used to evaluate the impact of Nrf3 on CM apoptosis and mitochondrial ROS production. Chromatin immunoprecipitation sequencing and immunoprecipitation-mass spectrometry analysis were used to uncover potential targets of Nrf3. MitoParaquat administration and CM-specific adeno-associated virus vectors were used to further confirm the in vivo relevance of the identified signal pathways.

RESULTS

Nrf3 was expressed mainly in CMs in healthy human hearts, and an increased level of Nrf3 was observed in CMs within the border zone of infarcted human hearts and murine cardiac tissues after MI. Both global and CM-specific Nrf3 knockout significantly decreased injury-induced mitochondrial ROS production, CM apoptosis, and pathological cardiac remodeling, consequently improving cardiac functions. In addition, cardiac-specific Nrf3 overexpression reversed the ameliorative cardiac phenotypes observed in Nrf3-KO mice. Functional studies showed that Nrf3 promoted neonatal mouse ventricular myocyte, neonatal rat ventricular myocyte, and CMs derived from human induced pluripotent stem cell apoptosis by increasing mitochondrial ROS production. Critically, augmenting mitochondrial ROS with MitoParaquat blunted the beneficial effects of Nrf3 deletion on cardiac function and remodeling. Mechanistically, a redox regulator Pitx2 (paired-like homeodomain transcription factor 2) was identified as one of the main target genes of Nrf3. Specifically, Nrf3 binds to Pitx2 promoter, where it increases DNA methylation through recruiting heterogeneous nuclear ribonucleoprotein K and DNA-methyltransferase 1 complex, thereby inhibiting Pitx2 expression. CM-specific knockdown of Pitx2 blunted the beneficial effects of Nrf3 deletion on cardiac function and remodeling, and cardiac-specific Pitx2 overexpression attenuated MI-induced mitochondrial ROS production and CM apoptosis, as well as preserved cardiac functions after MI.

CONCLUSIONS

Nrf3 promotes injury-induced CM apoptosis and deteriorates cardiac functions by increasing mitochondrial ROS production through suppressing Pitx2 expression. Targeting the Nrf3-Pitx2-mitochondrial ROS signal axis may therefore represent a novel therapeutic approach for MI treatment.

Unveiling the Toxic Mechanism of Arsenic on the Spleen of Cyprinus carpio and the Antagonistic Role of Zinc via the P38 MAPK/Nrf2/HO- 1 Pathway

Arsenic (As), a prevalent heavy metal, poses significant risks to the immune systems of living organisms. The spleen is considered one of the major immune organs of As-poisoned aquatic organisms. Zinc (Zn), known for its antioxidant and detoxification properties, may alleviate As-induced immune organ damage, but the underlying mechanism remains unclear. The P38 MAPK/Nrf2/HO- 1 signaling pathway is a crucial endogenous antioxidant pathway that protects organs and acts against cellular oxidative damage. This experiment was designed to investigate the splenic toxicity induced by As in carp and to evaluate the hypothesis that Zn alleviates oxidative stress and inflammatory injury induced by As via the P38 MAPK/Nrf2/HO- 1 signaling pathway. In the experiment, the spleen of the arsenic-exposed group exhibited significant endoplasmic reticulum dilation, formation of apoptotic bodies, and perinuclear cisternae, preliminarily confirming that As can cause severe tissue damage in the spleen of carp. Additionally, the transcriptional activity and protein synthesis of genes related to inflammatory response, oxidative stress, and apoptosis were significantly dysregulated. Notably, Zn supplementation significantly mitigated As-induced damage by enhancing antioxidant enzymes (CAT, SOD, GSH) and suppressing key mediators of stress and apoptosis (Nrf2, NF-κB, PERK, HSP60, and caspases). Additionally, Zn supplementation has been shown to mitigate As-induced spleen injury and associated pathological alterations, including inflammation and necrosis. These findings reveal, for the first time, that Zn alleviates As-induced spleen injury through the P38 MAPK/Nrf2/HO- 1 pathway, providing new insights into the detoxification mechanism of Zn and its potential application in mitigating heavy metal toxicity in aquaculture.

"SERBP1 (Hero45) is a Novel Link with Ischemic Heart Disease Risk: Associations with Coronary Arteries Occlusion, Blood Coagulation and Lipid Profile"

Ischemic heart disease (IHD), stemming from coronary atherosclerosis, involves pathological processes in which chaperone proteins play an essential role. SERBP1 (Hero45), an RNA-binding protein, has recently been ascribed to the newly discovered class of Hero proteins with chaperone-like activity, making it particularly relevant in atherosclerosis-related diseases. In this study, 2164 subjects (836 IHD patients and 1328 controls) were genotyped for five common single nucleotide polymorphisms (SNPs) of SERBP1 using probe-based PCR. Here, we report that SNPs of SERBP1 are associated with reduced risk of left coronary artery atherosclerosis: rs4655707 (effect allele [EA] T, OR = 0.63, 95% CI 0.43-0.93, p = 0.02), (EA C, OR = 0.63, 95% CI 0.42-0.95, p = 0.02), rs12561767 (EA G, OR = 0.65, 95% CI 0.45-0.96, p = 0.03), rs6702742 (EA A, OR = 0.63, 95% CI 0.43-0.94, p = 0.02). Additionally, SERBP1 loci are linked to lower coronary artery stenosis (rs1058074), improved blood lipid profiles (rs1058074), and favorable blood coagulation parameters (rs4655707, rs6702742, rs1058074, rs12561767). Together, our study is the first to provide evidence that SERBP1 is involved in lipid metabolism and coagulation regulation, modulating IHD risk.

Paricalcitol alleviates intestinal ischemia-reperfusion injury via inhibition of the ATF4-CHOP pathway

Introduction

Intestinal ischemia reperfusion (I/R) injury is a severe condition characterized by inflammation, oxidative stress, and compromised intestinal barrier function, which can lead to death. This study investigated the effects of paricalcitol, a synthetic vitamin D receptor (VDR) agonist, on intestinal I/R injury, focusing on the activating transcription factor 4 (ATF4)-C/EBP homologous protein (CHOP) signaling pathway and the modulation of endoplasmic reticulum stress (ERS).

Methods

This study consists of both in vivo and in vitro experiments. In vivo experiment, a mouse model of intestinal I/R injury was established by clamping the superior mesenteric artery, and followed by 24 or 72 h of reperfusion. 6-week-old male C57BL/6 J mice were randomly assigned to six groups: sham, I/R 24h, I/R 72 h, and their respective paricalcitol-treated counterparts. VDR knockout mice and wild-type mice were assigned to WT, VDR-KO, WT + I/R and VDR-KO + I/R groups. The paricalcitol-treated groups received oral gavage of paricalcitol (0.3 μg/kg) once daily for 5 days before I/R. In vitro, IEC-6 cells were incubated in a microaerophilic system (5% CO2, 1% O2, 94% N2) for 6 h to induce hypoxia. The cells were then transferred to complete medium with or without paricalcitol (200 nM) and cultured under normoxic conditions for 24 h to establish the hypoxia/re-oxygenation (H/R) model and investigate the protective effects of paricalcitol on H/R-induced injury in cells. We further utilized VDR- and ATF4-silenced cells to examine how paricalcitol regulates the expression of VDR, ATF4, and CHOP.

Results

We demonstrated that protective paricalcitol treatment reduces ERS and apoptosis by activating VDR and inhibiting the ATF4-CHOP pathway, thereby alleviating intestinal I/R injury in vivo and H/R injury in vitro. Furthermore, experiments with VDR knockout mice demonstrated that the absence of VDR exacerbated I/R injury, underscoring the protective role of VDR in intestinal epithelial cells.

Discussion

These findings suggest that the protective effects of paricalcitol may offer a promising therapeutic strategy for managing intestinal I/R injury.

Sigma-1 Receptor Specific Biological Functions, Protective Role, and Therapeutic Potential in Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and there is an urgent need for efficient and cost-effective treatments to decrease the risk of CVD. The sigma-1 receptor (S1R) plays a role in the development of cardiac hypertrophy, heart failure, ventricular remodeling, and various other cardiac diseases. Preclinical studies have shown that S1R activation has considerable beneficial effects on the cardiovascular system, and this knowledge might contribute to informing clinical trials associated with the prevention and treatment of CVDs. Therefore, the objective of this review was to investigate the mechanisms of S1R in CVD and how modulation of pathways contributes to cardiovascular protection to facilitate the development of new therapeutic agents targeting the cardiovascular system.

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

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

Identification and validation of endoplasmic reticulum stress-related diagnostic biomarkers for type 1 diabetic cardiomyopathy based on bioinformatics and machine learning

Background

Diabetic cardiomyopathy (DC) is a serious complication in patients with type 1 diabetes mellitus and has become a growing public health problem worldwide. There is evidence that endoplasmic reticulum stress (ERS) is involved in the pathogenesis of DC, and related diagnostic markers have not been well-studied. Therefore, this study aimed to screen ERS-related genes (ERGs) with potential diagnostic value in DC.

Methods

Gene expression data on DC were downloaded from the GEO database, and ERGs were obtained from The Gene Ontology knowledgebase. Limma package analyzed differentially expressed genes (DEGs) in the DC and control groups, and then integrated with ERGs to identify ERS-related DEGs (ERDEGs). The ERDEGs diagnostic model was developed based on a combination of LASSO and Random Forest approaches, and the diagnostic performance was evaluated by the area under the receiver operating characteristic curve (ROC-AUC) and validated against external datasets. In addition, the association of the signature genes with immune infiltration was analyzed using the CIBERSORT algorithm and the Spearman correlation test.

Results

Gene expression data on DC were downloaded from the GEO database and ERGs were obtained from the Gene Ontology Knowledgebase. Limma package analysis identified 3100 DEGs between DC and control groups and then integrated with ERGs to identify 65 ERDEGs. Four diagnostic markers, Npm1, Jkamp, Get4, and Lpcat3, were obtained based on the combination of LASSO and random forest approach, and their ROC-AUCs were 0.9112, 0.9349, 0.8994, and 0.8639, respectively, which proved their diagnostic potential in DC. Meanwhile, Npm1, Jkamp, Get4, and Lpcat3 were validated by external datasets and a mouse model of type 1 DC. In addition, Npm1 was significantly negatively correlated with plasma cells, activated natural killer cells, or quiescent mast cells, whereas Get4 was significantly positively correlated with quiescent natural killer cells and significantly negatively correlated with activated natural killer cells (P < 0.05).

Conclusions

This study provides novel diagnostic biomarkers (Npm1, Jkamp, Get4, and Lpcat3) for DC from the perspective of ERS, which provides new insights into the development of new targets for individualized treatment of type 1 diabetic cardiomyopathy.

Protective functions of liver X receptor α on calcified aortic valve: involvement of regulating endoplasmic reticulum-mediated osteogenic differentiation

AIMS

Effective therapeutic drugs for calcific aortic valve disease (CAVD) are lacking, although its incidence has been increasing over the past decade, and is predicted to continue rising in the future. This study aimed to explore the role and potential mechanisms of liver X receptor α (LXRα) in CAVD, which offers a promising approach for treating CAVD.

METHODS AND RESULTS

Osteogenic stimulation was performed following which a substantial downregulation of LXRα was observed in human calcific aortic valves and in valvular interstitial cells. Further functional investigations revealed that silencing LXRα exacerbated calcification both in vitro and in vivo. We showed that LXRα suppressed the protein kinase R-like ER kinase (PERK)/eukaryotic initiation factor 2 (elF2α)/activating transcription factor 4 (ATF4) pathway, which controls endoplasmic reticulum stress (ERS) and promotes osteogenic differentiation thereby slowing the course of CAVD.

CONCLUSION

Our research offers fresh perspectives on how LXRα controls the pathophysiology of CAVD via regulating ERS. The findings suggest that targeting LXRα is a potential treatment strategy for treating aortic valve calcification.

LEF1 influences diabetic retinopathy and retinal pigment epithelial cell ferroptosis via the miR-495-3p/GRP78 axis through lnc-MGC

BACKGROUND

Diabetic retinopathy (DR) is one of the major eye diseases contributing to blindness worldwide. Endoplasmic reticulum (ER) stress in retinal cells is a key factor leading to retinal inflammation and vascular leakage in DR, but its mechanism is still unclear.

AIM

To investigate the potential mechanism of LEF1 and related RNAs in DR.

METHODS

ARPE-19 cells were exposed to high levels of glucose for 24 hours to simulate a diabetic environment. Intraperitoneally injected streptozotocin was used to induce the rat model of DR. The expression levels of genes and related proteins were measured by RT-qPCR and Western blotting; lnc-MGC and miR-495-3p were detected by fluorescent in situ hybridization; CCK-8 and TUNEL assays were used to detect cell viability and apoptosis; enzyme-linked immunosorbent assay was used to detect inflammatory factors; dual-luciferase gene assays were used to verify the targeting relationship; and the retina was observed by HE staining.

RESULTS

LEF1 and lnc-MGC have binding sites, and lnc-MGC can regulate the miR-495-3p/GRP78 molecular axis. In high glucose-treated cells, inflammation was aggravated, the intracellular reactive oxygen species concentration was increased, cell viability was reduced, apoptosis was increased, the ER response was intensified, and ferroptosis was increased. As an ER molecular chaperone, GRP78 regulates the ER and ferroptosis under the targeting of miR-495-3p, whereas inhibiting LEF1 can further downregulate the expression of lnc-MGC, increase the level of miR-495-3p, and sequentially regulate the level of GRP78 to alleviate the occurrence and development of DR. Animal experiments indicated that the knockdown of LEF1 can affect the lnc-MGC/miR-495-3p/GRP78 signaling axis to restrain the progression of DR.

CONCLUSION

LEF1 knockdown can regulate the miR-495-3p/GRP78 molecular axis through lnc-MGC, which affects ER stress and restrains the progression of DR and ferroptosis in retinal pigment epithelial cells.

Cardiotoxicity of tris(2-chloroethyl) phosphate exposure: Insights into the role of oxygen sensor mediated energy metabolism remodeling

Tris(2-chloroethyl) phosphate, an extensively used organophosphorus flame retardant in consumer products, has caused pervasive environmental contamination and increased human exposure, raising concerns about its cardiotoxic potential. However, the detailed toxicological profile, particularly concerning the crucial cardiac energy metabolism, and the precise mechanisms remain poorly understood. This study in C57BL/6 J mice exposed to TCEP for 36 days at varying doses revealed cardiac dysfunction, structural abnormalities, and hypoxia. Analysis of energy metabolism indicated a shift from aerobic processes (tricarboxylic acid cycle, β-oxidation, and oxidative phosphorylation) to anaerobic metabolism (glycolysis). Further restoration of energy metabolism remodeling, which was achieved by activating oxidative phosphorylation and inhibiting glycolysis, mitigated TCEP-induced cardiotoxicity, highlighting the critical role of energy metabolism remodeling in TCEP-induced cardiac injury. Mechanistically, this metabolic remodeling was primarily driven by TCEP-enhanced hyperubiquitination and degradation of prolyl hydroxylase domain 2 (PHD2), leading to the accumulation and nuclear translocation of hypoxia-inducible factor-1α (HIF-1α). This study yields key insights into the cardiotoxicity of TCEP-like OPFRs exposure, and emphasizes the role of altered cardiac energy metabolism and the oxygen-sensing pathway, thereby proposing potential intervention strategies for OPFR-induced cardiac toxicity.

VEGF-B is a novel mediator of ER stress which induces cardiac angiogenesis via RGD-binding integrins independent of VEGFR1/NRP activities

Vascular endothelial growth factor B186 (VEGF-B186), a ligand for VEGF receptor 1 (VEGFR1) and neuropilin (NRP), promotes vascular growth in healthy and ischemic myocardium. However, the mechanisms and signaling of VEGF-B186 to support angiogenesis have remained unclear. We studied the effects of VEGF-B186 and its variant, VEGF-B186R127S, which cannot bind to NRPs, using VEGFR1 tyrosine kinase knockout (TK-/-) mice to explore the mechanism of VEGF-B186 in promoting vascular growth. Ultrasound-guided adenoviral VEGF-B186, VEGF-B186R127S, and control vector gene transfers were performed into VEGFR1 TK-/- mice hearts. In vitro studies in cardiac endothelial cells and further validation in normal and ischemic pig hearts, as well as in wild-type mice, were conducted. Both VEGF-B186 forms promoted vascular growth in VEGFR1 TK-/- mouse heart and increased the expression of proangiogenic and hematopoietic factors. Unlike VEGF-A, VEGF-B186 forms induced endoplasmic reticulum (ER) stress via the upregulation of Binding immunoglobulin Protein (BiP) as well as ER stress sensors (ATF6, PERK, IRE1α) through ITGAV and ITGA5 integrins, newly identified receptors for VEGF-B, activating the unfolded protein response (UPR) through XBP1. VEGFR1 and NRP are not essential for VEGF-B186-induced vascular growth. Instead, VEGF-B186 can stimulate cardiac regeneration through RGD-binding integrins and ER stress, suggesting a novel mechanism of action for VEGF-B186.

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Berberine and its derivatives: mechanisms of action in myocardial vascular endothelial injury - a review

Myocardial vascular endothelial injury serves as a crucial inducer of cardiovascular diseases. Mechanisms such as endoplasmic reticulum stress, apoptosis, inflammation, oxidative stress, autophagy, platelet dysfunction, and gut microbiota imbalance are intimately linked to this condition. Berberine and its derivatives have demonstrated potential in modulating these mechanisms. This article reviews the pathogenesis of endothelial injury in myocardial vessels, the pharmacological effects of berberine and its derivatives, particularly their interactions with targets implicated in vascular endothelial injury. Furthermore, it discusses clinical applications, methods to enhance bioavailability, and toxicity concerns, aiming to lay a foundation for the development of BBR as a therapeutic agent for cardiovascular diseases.

Homeostasis control in health and disease by the unfolded protein response

Cells rely on the endoplasmic reticulum (ER) to fold and assemble newly synthesized transmembrane and secretory proteins - essential for cellular structure-function and for both intracellular and intercellular communication. To ensure the operative fidelity of the ER, eukaryotic cells leverage the unfolded protein response (UPR) - a stress-sensing and signalling network that maintains homeostasis by rebalancing the biosynthetic capacity of the ER according to need. The metazoan UPR can also redirect signalling from cytoprotective adaptation to programmed cell death if homeostasis restoration fails. As such, the UPR benefits multicellular organisms by preserving optimally functioning cells while removing damaged ones. Nevertheless, dysregulation of the UPR can be harmful. In this Review, we discuss the UPR and its regulatory processes as a paradigm in health and disease. We highlight important recent advances in molecular and mechanistic understanding of the UPR that enable greater precision in designing and developing innovative strategies to harness its potential for therapeutic gain. We underscore the rheostatic character of the UPR, its contextual nature and critical open questions for its further elucidation.

Endoplasmic reticulum stress and unfolded protein response in renal lipid metabolism

The endoplasmic reticulum (ER) is a crucial cellular organelle involved in protein synthesis, folding, modification, and transport. Exposure to internal and external stressors can induce endoplasmic reticulum stress (ERS), leading to abnormal protein folding and ER malfunction. This stress can disrupt lipid synthesis, metabolism, and transport processes. Fatty acid oxidation is the primary energy source for the renal system. When energy intake exceeds the storage capacity of adipose tissue, lipids accumulate abnormally in non-adipose tissues, including kidneys, liver, and pancreas. Lipids accumulate in the kidneys of nearly all cell types, including thylakoid membranous, pedunculated, and proximal renal tubular epithelial cells. Intracellular free fatty acids can significantly disrupt renal lipid metabolism, contributing to ischemia-reperfusion acute kidney injury, diabetic nephropathy, renal fibrosis, and lupus nephritis. Consequently, this study delineated the primary signaling pathways and mechanisms of the ERS-induced unfolded protein response, explored the mechanistic link between ERS and lipid metabolism, and elucidated its role in renal lipid metabolism. This study aimed to offer new perspectives on managing and treating renal disorders.

Screening of biomarkers for diagnosing chronic kidney disease and heart failure with preserved ejection fraction through bioinformatics analysis

Background

Previous research has established that chronic kidney disease (CKD) and heart failure with preserved ejection fraction (HFpEF) often coexist. Although we have a preliminary understanding of the potential correlation between HFpEF and CKD, the underlying pathophysiological mechanisms remain unclear. This study aimed to elucidate the molecular mechanisms associated with CKD and HFpEF through bioinformatics analysis.

Methods

Datasets for HFpEF and CKD were obtained from the Gene Expression Omnibus (GEO) database. The R software package "limma" was employed to conduct differential expression analysis. Functional annotation was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). We conducted weighted gene co-expression network analysis (WGCNA), correlation analysis with autophagy, ferroptosis, and immune-related processes, as well as transcriptional regulation analysis, immune infiltration analysis, and diagnostic performance evaluation. Finally, the diagnostic potential of the identified hub genes for CKD and HFpEF was assessed using ROC curve analysis (GSE37171).

Results

Differential expression analysis revealed 58 overlapping genes, comprised of 40 up-regulated and 18 down-regulated genes. Both GO and KEGG analyses indicated enriched pathways relevant to both disorders. WGCNA identified 4086 genes associated with CKD. Further comparison with differentially expressed genes (DEGs) identified three hub genes (KLF4, SCD, and SEL1L3) that were linked to autophagy, ferroptosis, and immune processes in both conditions. Additionally, a miRNA-mRNA regulatory network involving 376 miRNAs and 12 transcription factors (TFs) was constructed. ROC curve analysis was performed to evaluate the diagnostic utility of the hub genes for CKD and HFpEF.

Conclusion

This study elucidated shared pathogenic mechanisms and identified diagnostic markers common to both HFpEF and CKD. The identified hub genes show promise as potential tools for early diagnosis and treatment strategies for these conditions.

Direct inhibition of macrophage sting signaling by curcumol protects against myocardial infarction via attenuating the inflammatory response

BACKGROUND

Macrophages play a crucial role in the pathological process after myocardial infarction (MI). However, pharmacological therapy targeting this pathway remains undefined. Curcumol, a natural compound extracted from the Curcumae Rhizoma, has demonstrated anti-tumor and anti-inflammatory activities. Therefore, this study aimed to explore the potential of curcumol as a therapeutic agent for MI.

METHODS

Wild-type (WT) mice were administered with curcumol orally following left coronary artery ligation. The effects of curcumol on post-MI inflammatory responses were evaluated through phenotypic analysis, histology, and flow cytometry. RNA sequencing, surface plasmon resonance (SPR), and molecular docking were utilized to identify the molecular target of curcumol. Functional studies were further conducted using stimulator of interferon genes (STING) knockout (Sting-/-) mice.

RESULTS

Curcumol treatment improved the survival rate in mice following MI while enhancing cardiac function and mitigating adverse post-infarction ventricular remodeling. Transcriptomic analysis and SPR indicated curcumol directly bound to STING. Functional assays demonstrated that the cardio-protective effects of curcumol were mediated via STING, as these effects were diminished in Sting-/- mice. Mechanistically, curcumol disrupted STING-TBK1 interaction, suppressing downstream signaling activation and type I interferon responses. Notably, curcumol exhibited stronger inhibition of activated STING signaling in macrophages and superior cardioprotective effects compared to the STING inhibitor H-151.

CONCLUSION

Curcumol targets STING to suppress type I interferon responses, improving cardiac function post-MI. These findings highlight curcumol as a promising therapeutic candidate for MI treatment.

Caveolin-3: therapeutic target for diabetic myocardial ischemia/reperfusion injury

Myocardial ischemia/reperfusion (I/R) injury is a major global health problem with high rates of mortality and disability, which is more severe in patients with diabetes. Substantial researches have documented that diabetic myocardium are more susceptible to I/R injury, but many current intervention strategies against myocardial I/R injury have limited effectiveness in diabetic hearts. Caveolin-3 (Cav-3) is the signature protein of caveolae and serves as a signal integration and transduction platform in the plasma membrane of cardiomyocytes, which plays a vital role in myocardial functions, metabolism and protection of multiple conditioning strategies against I/R injury. Nevertheless, numerous studies have revealed that the expression of Cav-3 is impaired in diabetic hearts, which contributes to increased vulnerability of myocardium to I/R injury and resistance to protective conditioning strategies. In this review, we outline the basic structure and function of Cav-3, emphatically present the unique role of Cav-3 as a signal integration and transduction element in diabetic myocardial I/R injury and discuss its therapeutic perspective in strategies against myocardial I/R injury in diabetes.

Therapeutic implications of endoplasmic reticulum stress gene CCL3 in cervical squamous cell carcinoma

This study investigated ERS-related gene expressions in CESC, identifying two molecular subtypes, P1 and P2, and constructing a precise prognostic model based on these subtypes. TCGA's whole-genome expression profiles were used to recognize these subtypes through the ConsensusClusterPlus method, further refining prognostic models with univariate and Lasso Cox regression analyses validated by the GSE39001 dataset. The study analyzed the expression distribution of ERS marker genes within T cell subgroups using scRNA-seq data (GSE168652), highlighting T cell diversity. The critical role of the CCL3 gene in prognostic models was examined explicitly in CD8 + T cells from healthy individuals and CESC patients. Elevated CCL3 levels were observed in patients' CD8 + T cells compared to healthy controls. Functional experiments involving CCL3 knockdown and overexpression in HeLa and SiHa CESC cell lines were conducted to investigate its impact on cell proliferation, migration, and invasion. These findings were subsequently validated in a nude mouse model. The results demonstrated that suppressing CCL3 inhibited cell proliferation, migration, and invasion significantly, while its overexpression promoted these processes. In the mouse model, CCL3 silencing reduced tumor growth and decreased Ki-67 labeling within the tumor tissues, indicating the therapeutic potential of targeting CCL3 in CESC treatment, possibly through CD8 + T cell regulation. This study contributes new prognostic assessment tools and personalized treatment options for CESC patients, paving the way for more targeted therapies in CESC by discovering the CCL3 gene, presenting significant clinical implications.

Sephin1 suppresses ER stress-induced cell death by inhibiting the formation of PP2A holoenzyme

Sephin1 was discovered as a protein phosphatase inhibitor, and its efficacy against neurodegenerative diseases has been confirmed. There are conflicting reports on whether inhibition of eIF2α dephosphorylation by PP1 holoenzyme with the protein phosphatase 1 regulatory subunit 15 A is the mechanism of action of Sephin1. In the present study, we found that Sephin1 significantly suppressed renal tubular cell death in an animal model of ER stress administered with tunicamycin. CHOP, which plays a central role in the ER stress-induced cell death pathway, requires nuclear translocation to act as a transcription factor to increase the expression of cell death-related genes. Sephin1 markedly suppressed this nuclear translocation of CHOP. To elucidate the molecular mechanism underlying the cell death suppressive effect of Sephin1, we used human renal tubular epithelial cells under ER stress with tunicamycin. Sephin1 reduced intracellular CHOP levels by promoting CHOP phosphorylation at Ser30, which led to protein degradation in UPS. Phosphorylated CHOP is generated by Thr172-phosphorylated activated AMPK, and Sephin1 increased phosphorylated AMPK. Phosphorylated AMPK is inactivated by PP2A through dephosphorylation of its Thr172, and Sephin1 inhibits the formation of the PP2A holoenzyme with the PP2A subunit B isoform delta. These results indicate that inhibition of PP2A holoenzyme formation is the molecular target of Sephin1 in this experimental system.

Farnesol Improves Endoplasmic Reticulum Stress and Hepatic Metabolic Dysfunction Induced by Tunicamycin in Mice

Endoplasmic reticulum (ER) stress significantly affects liver metabolism, often leading to disorders such as hepatic steatosis. Tunicamycin (TM), a known ER stress inducer, is frequently used to model metabolic stress, but its specific effects on liver energy homeostasis remain unclear. This study investigates how farnesol (FOH), a natural compound with antioxidant and anti-inflammatory properties, counteracts TM-induced ER stress and its associated metabolic disruptions in the liver. Using both primary hepatocytes and a mouse model, this study demonstrates that TM treatment caused upregulation of ER stress markers, including ATF4, and disrupted genes related to lipid metabolism and gluconeogenesis. Co-treatment with FOH reduced these stress markers and restored the expression of metabolic genes. In vivo, FOH treatment alleviated oxidative stress, reduced lipid accumulation, and restored normal glycogen and lipid metabolism. Histological analysis further confirmed that FOH preserved liver architecture and minimized cellular damage. FOH also stabilized serum lipid profiles and modulated key metabolic biomarkers, suggesting its protective role against TM-induced liver injury. These findings suggest that FOH has therapeutic potential in mitigating ER stress-related metabolic dysfunctions, offering promising insights for the treatment of liver diseases linked to metabolic stress.