Search Results (601)

Epidermal lipid homeostasis is crucial for skin barrier integrity. This study investigated the effects of an aqueous extract from Beta vulgaris subsp. vulgaris Beetroot Group (BvE) on stress responses and lipid metabolism in HaCaT keratinocytes. BvE, obtained from leaves grown in SETIS^® bioreactors as a standardized biomass source, was chemically characterized by ¹H NMR and ¹³C NMR. HaCaT cells were treated with BvE (1 µg/mL), H₂O₂, or palmitic/oleic acids (PA/OA) to evaluate its protective effects against oxidative damage and lipotoxic stress. Under these conditions, BvE exhibited a distinctive dual action as a reactive oxygen species (ROS) scavenger and triacylglycerol (TAG)-lowering agent. On the one hand, BvE was associated with decreased intracellular ROS levels and changes in NRF2 protein expression, suggesting involvement of redox-regulatory pathways. On the other hand, it was associated with attenuation of lipotoxicity, as evidenced by reduced lipid droplet (LD) formation and decreased expression of DGAT1 and PLIN2. Furthermore, these effects were accompanied by a reduction in Unfolded Protein Response (UPR) markers, modulation of AMPK-associated signaling, attenuation of mitochondrial disfunction, and decreased p53 phosphorylation, findings collectively consistent with a coordinated cytoprotective response. In conclusion, BvE shows potential to protect keratinocytes against lipotoxicity and oxidative stress through mechanisms that may involve both chemical and biological antioxidant activity and metabolic reprogramming, supporting its further investigation for dermatological applications. Full article

Background: T-cell acute lymphoblastic leukemia (T-ALL) remains a challenging malignancy with limited targeted therapies. Natural phenanthrene derivatives represent a promising source of antileukemic agents. Objective: We screened a library of natural phenanthrene-type compounds to identify cytotoxic leads in Jurkat T-ALL cells and investigated the mechanisms underlying their activity, including potential synergy with the proteasome inhibitor bortezomib (BTZ). Methods: Jurkat cells were treated with thirteen natural compounds at 10 and 20 µM for 48 h; cell viability was assessed by WST-1 cell viability assay. Dose–response curves were generated to calculate IC₅₀ values. Apoptosis was evaluated by Hoechst 33342/PI staining and Annexin V/PI flow cytometry. Synergy with BTZ was analyzed using a fixed-ratio combination index (CI) approach and IC₅₀ shift analysis. ER stress signaling was characterized by Western blotting, quantitative RT-PCR of UPR genes (GRP78, ATF6), and immunoprecipitation of GRP78 followed by ubiquitin immunoblotting. Results: Among the compounds screened, Cypripedin showed the most potent cytotoxicity with an IC₅₀ of 6.52 µM. It induced a dose-dependent increase in apoptosis. Combination with BTZ yielded a CI < 0.5 and reduced BTZ IC₅₀ from 3.43 to 1.88 ng/mL. Cypripedin activated the unfolded protein response (UPR), modulated key ER stress markers including GRP78, p-PERK, p-eIF2α, p-JNK, and ATF6, downregulated UPR gene transcripts, and promoted GRP78 ubiquitination. Molecular docking predicted strong binding of Cypripedin to the GRP78 ATPase domain (Vina score −7.630 kcal/mol), supporting its mechanism of action. Conclusion: Cypripedin induces apoptosis in Jurkat T-ALL cells, synergizes with BTZ, and modulates ER stress through GRP78 ubiquitination. These findings support its further development as a potential T-ALL therapeutic. Full article

Gestational diabetes mellitus (GDM) is increasingly recognized as a complex pathology rooted in systemic and organelle-level dysfunction, specifically involving chronic low-grade inflammation (CLGI), mitochondrial impairment, and endoplasmic reticulum (ER) stress. Central to this pathophysiology is mitochondrial dysfunction, characterized by reduced respiration, impaired metabolic flexibility, and dysregulated fission/fusion machinery, which fuels a self-perpetuating cycle of reactive oxygen species (ROS) production. Concurrently, chronic ER stress triggered by hyperglycemia and lipotoxicity activates the unfolded protein response (UPR), further amplifying redox imbalance through the Endoplasmic Reticulum Oxidoreductin 1/Protein Disulfide Isomerase (ERO1/PDI) axis and bridging metabolic toxicity to inflammation via c-Jun N-terminal kinase (JNK) and nuclear factor kappa-light-chain–enhancer of activated B cells (NF-κB) signaling. The Advanced Glycation Endproducts (AGEs) and the Receptor for Advanced Glycation Endproducts (RAGE) axis act as a molecular catalyst that sequester antioxidants and drive pro-inflammatory feedback loops. These converging mechanisms culminate in profound placental maladaptation, including structural abnormalities like chorangiosis and functional defects in nutrient transport mediated by hyperactive mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review article provides insight into recent evidence to elucidate the meta-inflammatory environment of GDM, where modest but sustained elevations in biomarkers like Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) disrupt redox homeostasis and impair insulin signaling pathways through the activation of stress-sensitive kinases. By integrating these molecular perspectives, the article underscores the necessity of targeting the systemic inflammatory and oxidative continuum spanning pre-conception to the antenatal period through lifestyle interventions and emerging therapeutic strategies to mitigate GDM risk and improve maternal–fetal outcomes. Full article

Prostate cancer (PCa) remains lethal at advanced stages, partly due to stem-like subpopulations known as prostate cancer stem cells (PCSCs) that sustain tumor growth and therapeutic resistance. Imipridones are small-molecule anticancer agents, with next-generation derivatives ONC206 and ONC212 designed for enhanced potency and broader activity. This study compared their antitumor efficacy and mechanisms in advanced androgen-independent PCa (AIPC) models, namely DU145 and PC3 cells, using two- and three-dimensional systems encompassing bulk cancer cells and PCSCs. DU145 and PC3 AIPC cells were treated with ONC201 (parent compound), ONC206, or ONC212. Functional assays assessed proliferation, viability, migration, invasion, PCa spheroids formation, cell cycle distribution, and mitochondrial membrane potential and mass, while RNA sequencing defined transcriptional responses. ONC212 was the most potent derivative, inhibiting proliferation and migration and abolishing PCa spheroids at nanomolar doses, whereas ONC201 and ONC206 required higher concentrations. Transcriptomic analyses revealed shared repression of DNA replication and cell-cycle transition programs, with activation of integrated stress and unfolded protein responses (ISR/UPR) and FOXO signaling. ONC206 favored PERK–ATF4-mediated apoptosis with reduced DNA repair, while ONC212 more strongly impacted oxidative phosphorylation-related pathways and mitochondrial RNA processing. Imipridones induced a time-dependent cell-cycle redistribution with increased sub-G1 accumulation and modulated mitochondrial membrane potential and mass in a context-dependent manner. Collectively, these findings position ONC212 as a leading imipridone candidate in AIPC models, combining potent inhibition of tumor and stem-like cell functions with a coherent stress-response signature that supports further translational evaluation. Full article

The IRE1α-XBP1 axis is the most conserved of the three major unfolded protein response (UPR) branches triggered by the endoplasmic reticulum (ER) stress. Although the transcription factor XBP1 is involved in the development and function of several hematopoietic lineages, its role in the activation of mast cells (MCs), which are critical in allergic responses, remains largely unknown. We identified salicylaldehyde, which suppresses IRE1α nuclease activity that is essential for XBP1 production, as an inhibitor of MC activation in our previous screening; therefore, we herein investigated the effects of additional IRE1α inhibitors, 3-methyl-6-bromo-salichylaldehyde (MBSA) and KIRA6, targeting the nuclease domain and kinase domain, respectively, on MC activation. MBSA and KIRA6 suppressed IgE-dependent degranulation of bone marrow-derived MCs (BMMCs) but did not inhibit Ca²⁺ ionophore- or compound48/80-induced degranulation. Treatments with inhibitors of two other branches of UPR, the PERK and ATF6 pathways, did not affect the IgE-induced activation of BMMCs. The intraperitoneal administration of MBSA or KIRA6 significantly suppressed IgE-induced passive anaphylaxis in mice. Furthermore, to examine the effects of XBP1, siRNA-mediated knockdown was performed. The results obtained confirmed that Xbp1 siRNA introduction reduced the IgE-dependent degranulation of BMMCs in parallel with the knockdown level of Xbp1 mRNA. Therefore, the IRE1α-XBP1 axis plays a significant role in IgE-dependent and MC-mediated allergic responses and is considered to be a therapeutic target of allergic diseases. Full article

Obesity contributes to an increase in the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) and is diagnosed when hepatic steatosis is accompanied by at least one of the following factors: obesity or overweight, diabetes mellitus, or signs of metabolic abnormalities. MAFLD is a term that encompasses a wide range of liver disorders, ranging from simple steatosis to metabolic steatohepatitis, which can progress to cirrhosis and eventually, hepatocellular carcinoma (HCC). Lipotoxicity generated by a high-fat diet causes liver inflammation, therefore, blocking inflammatory pathways is considered a promising strategy to prevent MAFLD progression. Inflammatory responses and oxidative stress are linked to endoplasmic reticulum stress, thereby activating the unfolded protein response (UPR) pathway. Although drugs such as resmetirom and semaglutide have recently been approved for the treatment of MAFLD, there is still a need to identify complementary therapies with different mechanisms of action. In this context, the present study evaluated the hepatoprotective effect of ellagic acid through the modulation of mRNAs of proteins in the UPR-Perk pathway in a murine model fed a high-calorie diet. This study revealed that the high-calorie diet activated the UPR pathway in response to stress, increasing the expression of the Grp78, Eif2ak3, Eif2α, Ddit3, Atf4, and Nfe2l2 genes in the liver and epididymal adipose tissue. Ellagic acid modulated the pathway genes and reduced levels of glucose, total cholesterol, HDL and VLDL, triglycerides, insulin, and glycated hemoglobin, and could therefore be considered a hepatoprotective agent. Full article

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by therapeutic resistance and poor prognosis, underscoring the need for new therapeutic strategies. Bufalin, a major bioactive constituent of Venenum bufonis, has shown antitumor activity in several cancer types; however, its mechanism of action in PDAC remains incompletely defined. In this study, we investigated the antitumor effects of bufalin in PDAC using in vitro assays, mouse tumor models, and integrative transcriptomic, proteomic, metabolomic, and bioinformatic analyses. Bufalin inhibited PDAC cell viability, clonogenic growth, migration, and tumor progression in vivo. Pharmacological rescue experiments indicated that ferroptosis contributes importantly to bufalin-induced cytotoxicity, although apoptosis- and pyroptosis-related pathways may also be involved. Multi-omics analyses revealed coordinated alterations in calcium homeostasis, endoplasmic reticulum (ER) stress/unfolded protein response (UPR) signaling, and ferroptosis-related metabolic pathways. Further experiments showed that bufalin was associated with disrupted intracellular Ca²⁺ homeostasis, IP₃R-linked ER Ca²⁺ release, activation of PERK/eIF2α/ATF4 signaling, increased ATF3 expression, reduced SLC7A11 and GPX4 expression, glutathione depletion, and enhanced lipid peroxidation. Molecular docking and surface plasmon resonance assays supported an in vitro physical interaction between bufalin and IP₃R1/IP₃R3, while inhibition of ER stress attenuated several bufalin-induced ferroptosis-related phenotypes. Bioinformatic analyses further showed that higher ER stress and ferroptosis signature scores were associated with improved overall survival in PDAC, and concurrent activation of both signatures was linked to the most favorable prognosis. Collectively, these findings support that bufalin suppresses PDAC progression through coordinated ER stress- and ferroptosis-related responses, highlighting ER stress-ferroptosis crosstalk as a potential therapeutic vulnerability in PDAC. Full article

Decidualization in the human endometrium is not merely a hormone-dependent differentiation process; rather, it represents a multilayered adaptive program characterized by the tight integration of immune regulation, metabolic reprogramming, and cellular stress responses. In this review, endoplasmic reticulum (ER) stress and the associated unfolded protein response (UPR) are proposed as central regulatory mechanisms governing this process. Triggered by increased protein synthesis and secretory demand, UPR activation under physiological conditions preserves proteostasis and supports the secretory capacity of stromal cells. In contrast, chronic or dysregulated activation leads to a maladaptive response characterized by apoptosis, inflammation, and metabolic dysfunction. UPR signaling pathways shape immune tolerance through their effects on macrophage polarization, uterine natural killer (uNK) cell function, and T cell balance. At the metabolic level, adenosine monophosphate-activated protein kinase (AMPK) regulates cellular adaptation through bidirectional interactions with mitochondrial function and redox homeostasis. Within this framework, the ER stress–immune–metabolic axis operates not as a linear pathway but as a dynamic network incorporating multiple feedback loops, thereby constituting a critical threshold mechanism that determines the success of decidualization. Disruption of this axis provides a shared mechanistic basis for pathologies such as recurrent implantation failure, pregnancy loss, and preeclampsia. From a therapeutic perspective, agents including chemical chaperones, UPR modulators, AMPK activators, and anti-inflammatory compounds hold translational potential by targeting these pathological feedback circuits. However, key knowledge gaps remain, particularly regarding the cell type-specific and temporal regulation of ER stress, the molecular boundaries defining the transition from adaptive to pathological states, and interspecies differences. Future studies employing single-cell omics approaches and functional in vivo models will be essential to elucidate the dynamic organization of this axis and to enable the development of targeted and personalized therapeutic strategies. Full article

Natural products remain a major source of anticancer agents, yet freshwater organisms are largely unexplored. Building on our previous evidence that planarian mucus exerts cytostatic and cytotoxic effects on cancer cells, we investigated the involvement of endoplasmic reticulum stress and unfolded protein response (UPR) pathways. Mucus-induced cytotoxicity is ROS-dependent and associated with depletion of intracellular reduced glutathione (GSH), not through inhibition of the System Xc⁻ transporter but potentially associated with upregulation of CHAC1, a glutathione-degrading enzyme. Mucus fractionation based on molecular weight identified the high-molecular-weight crude fraction as the one containing the bioactive entity, reproducing the effects of whole mucus. Treatment with this fraction early activates the PERK–ATF4 branch of the UPR, which could be responsible for driving CHAC1 induction. Moreover, ATF4 enhances DDIT3 expression, and activates a compensatory NRF2-dependent antioxidant response. At a later stage mucus also activates the IRE1α–XBP1 axis, with no ATF6 involvement, indicating selective UPR engagement in response to oxidative and lipid stress. Overall, our data are consistent with a potential PERK–ATF4–CHAC1–GSH self-sustaining axis promoting oxidative stress that culminates in cell death, supporting the potential of planarian mucus as a source of pleiotropic bioactive compounds, although the molecular identity of the active component(s) remains still unresolved. Full article

Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) represent fundamental cellular adaptive mechanisms that maintain protein homeostasis and metabolic balance. Many RNA viruses, particularly flaviviruses such as dengue virus (DENV), Zika virus (ZIKV), West Nile virus (WNV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV), extensively remodel the ER to establish replication compartments and assemble progeny virions. This massive reorganization disrupts ER homeostasis, leading to UPR activation. Emerging evidence reveals that flaviviruses not only trigger but also manipulate the three UPR branches—PERK, IRE1, and ATF6—to optimize viral translation, replication, and egress. In parallel, flavivirus infection profoundly alters host lipid metabolism and promotes dynamic changes in lipid droplets (LDs), key organelles that mediate lipid storage and serve as scaffolds for viral replication and assembly. The UPR intimately connects to LD biogenesis through transcriptional and translational programs mediated by XBP1, ATF4, and ATF6, thereby coupling ER stress responses to lipid remodeling and energy homeostasis. This intricate crosstalk between UPR and LDs creates a metabolic and structural niche favorable for viral replication but detrimental to host cell integrity. This review provides a comprehensive analysis of the molecular mechanisms by which flaviviruses exploit ER stress and the UPR to reprogram lipid metabolism and LD dynamics. We highlight the dual role of UPR signaling in promoting adaptive lipid synthesis and initiating cell death under prolonged stress, discuss recent insights into ER–LD interactions during flavivirus infection, and explore therapeutic opportunities targeting UPR–lipid metabolic pathways as broad-spectrum antiviral strategies. Understanding this interconnected network will advance our knowledge of viral pathogenesis and identify new avenues for host-directed antiviral intervention. Full article

Serglycin (SRGN) has been found overexpressed and secreted in glioblastoma (GBM), associated with tumorigenic signaling and poor prognosis. In this study, we aimed to elucidate the involvement of SRGN in the unfolded protein response (UPR), an oncogenic signaling pathway implicated in protein recycling and cell fate. Herein, we developed stably transduced LN-18^shSCR GBM cells, expressing high levels of SRGN, and SRGN-depleted LN-18^shSRGN cells. We observed significantly attenuated expression and activity of all UPR mediators upon SRGN suppression, in particular PERK, IRE1, ATF6 and downstream effectors. SRGN-expressing cells possessed a constitutively active UPR, as indicated by its active phosphorylation status and accumulated pool of nuclear ATF4 in LN-18^shSCR cells. Constitutive activation of the caspase-dependent apoptotic pathway was apparent in LN-18^shSRGN cells. Induction of endoplasmic reticulum (ER) stress pointed out that LN-18^shSRGN cells were predisposed to ER stress-associated cell death, whereas LN-18^shSCR cells activated adaptive UPR signaling and displayed resistance to apoptosis. The evaluation of TLRs, TNFRs, ILs and NF-kB also underscored that SRGN is essential for their expression and active inflammatory signaling. We concluded that SRGN-expressing cells acquire a pro-survival UPR mechanism, highlighting the novel regulatory role of SRGN in the adaptation and survival of GBM cells. Full article

Climate change has transformed extreme heat from a transient environmental perturbation into a persistent threat that worsens cardiovascular outcomes. Epidemiological studies show a lag between heat exposure and peaks in acute myocardial infarction (AMI) mortality, indicating a subclinical, latent vulnerability. This latent vulnerability likely originates at the level of the microvasculature, as cardiac microvascular endothelial cells (CMECs)—the heart’s primary “thermal sensors”—are uniquely susceptible to proteotoxic stress. The existing literature suggests that this sensitivity may be mediated by thermodynamically gated activation of the activating transcription factor 6 (ATF6) branch of the unfolded protein response (UPR), which could function as a master switch that reprograms endothelial cells from a pro-repair to a maladaptive, anti-angiogenic phenotype. However, this mechanism is derived primarily from preclinical studies and lacks direct validation in humans. The resulting “endothelial memory” is sustained by epigenetic modifications and organelle uncoupling; it persists beyond the initial insult and impairs subsequent neovascularization. As a result, ischemia occurs later in a compromised microenvironment, promoting a fibrosis–conduction mismatch that drives infarct expansion and arrhythmic risk. Thus, the post-exposure latent phase emerges as a novel therapeutic window: Precision targeting of the ER stress–angiogenesis axis during this period offers a focused strategy to protect heat-vulnerable individuals Full article

Yeast models are widely used to study molecular chaperones from diverse organisms, including plants, because of their well-characterized genetics and the conservation of the protein-folding machinery among eukaryotes. Cross-species complementation studies in yeast have yielded valuable insights into conserved biochemical activity and molecular functions that manage protein folding, assembly, and repair during stress. This study evaluated the functional capacity of three potato StBiP isoforms (StBiP1, StBiP2, and StBiP3) to complement the kar2 deletion (kar2Δ) strain under a range of environmental and ER stress conditions. All three StBiPs partially restored colony growth under normal conditions, demonstrating that they are functional orthologs of yeast KAR2 and can support core ER housekeeping functions. Under severe stress, however, the isoforms diverged: StBiP3 most effectively complemented the kar2Δ strain during heat- and chemically induced ER stress, whereas StBiP1 and StBiP2 provided weaker protection. Unfolded protein response (UPR) activation, monitored via HAC1 mRNA splicing, further highlighted isoform-specific differences in how the StBiPs support IRE1-HAC1 signaling under ER stress and oxidative stress. A conserved cysteine in the nucleotide-binding domain, previously implicated in Kar2 redox control, was also critical for StBiP3-mediated protection in yeast, although the same mutation led to different consequences in plant tissues. Together, these findings provide evidence of subfunctionalization among potato BiP isoforms, with StBiP3 emerging as a stress-specialized chaperone that is a promising target for improving ER stress resilience in solanaceous crops. Full article

Alpha-1 antitrypsin deficiency (AATD) is an inherited disorder characterized by intracellular retention of mutant Z (Pi*Z) alpha-1 antitrypsin (AAT) within hepatocytes, resulting in progressive liver disease. Currently, no approved pharmacological therapies exist for AATD-associated hepatic injury. Emerging preclinical evidence indicates that inhibition of mammalian target of rapamycin (mTOR) ameliorates liver pathology in AATD; however, the status of mTOR activity and its regulatory mechanisms under Pi*Z AAT-induced cellular stress remains incompletely understood. In this study, we investigated alterations in mTOR signaling and its upstream regulatory pathways using a gene-edited human hepatocyte model harboring the Pi*Z mutation (Huh7.5Z cells) and a Pi*Z AAT transgenic mouse model. Attenuation of mTORC1 activity was observed in both cellular and murine Pi*Z models. In vitro analyses demonstrated activation of AMP-activated protein kinase (AMPKα), a key inhibitory regulator of mTORC1, accompanied by paradoxical activation of Akt and the unfolded protein response (UPR) branch ATF6α. Pharmacological inhibition of mTOR significantly reduced intracellular Pi*Z AAT accumulation, alleviated ER stress, and suppressed apoptotic signaling through enhancement of autophagy. These findings reveal that hepatocytes adapt to Pi*Z AAT-induced stress through coordinated regulation of mTOR by AMPK, Akt, and ATF6α pathways. This study provides mechanistic insight into metabolic and stress-response signaling in AATD and identifies mTOR modulation as a promising therapeutic strategy for AATD-associated liver disease. Full article

Background: The aminosteroid RM-581 exhibits strong antiproliferative activity against cell lines from more than 10 solid tumor cancers, including some with poor prognoses. However, RM-581’s impact has never been assessed on leukemia. Methods: Cellular responses to RM-581 were evaluated using complementary approaches. Cytotoxicity was quantified using MTS-based viability assays and drug interactions were analyzed according to the Chou-Talalay method. Flow cytometry was employed to assess apoptosis, cell cycle distribution and effects on lymphocytes subpopulations. The transcriptomic profile was investigated by mRNA sequencing to identify differentially expressed genes and associated pathways. Results: Its evaluation on six leukemia cell lines (HL-60, THP-1, JURKAT, K-562, HG-3 and JVM-2) showed that RM-581 efficiently blocked the proliferation of leukemia cells. In healthy peripheral blood lymphocytes, flow cytometry revealed a significant impact on T lymphocytes (CD3+), particularly cytotoxic T cells (CD8+), at 50 µM. In THP-1 cells, an acute monocytic leukemia cell line, RM-581 triggered apoptosis and induced G0/G1 cell cycle arrest, which was confirmed with a transcriptomic analysis of enriched pathways. The role of RM-581 as an endoplasmic reticulum (ER) stress aggravator was confirmed by observing an increase in ER stress markers, such as BIP (GRP-78), CHOP and HERP, and in unfolded protein response (UPR) effectors (PERK, IRE1α and ATF6). Conclusions: This study demonstrates that RM-581 could be a promising candidate to treat leukemia, notably through the induction of ER-stress mediated apoptosis. Full article