Search Results (114)

Cisplatin [cis-diamminedichloroplatinum(II)] is a widely used chemotherapeutic agent that induces cytotoxicity primarily through DNA damage; however, drug resistance severely limits its efficacy. Cisplatin resistance is complex and multifactorial, involving DNA repair via nucleotide excision repair (NER), increased detoxification activities, and overexpression of lysine deacetylases (KDACs), which reduce chromatin accessibility and alter transcriptional regulation. Combining cisplatin with KDAC inhibitors has shown promise, often attributed to increased drug sensitivity through higher chromatin accessibility; however, this hypothesis has not been validated. Here, we synthesized a novel Pt(IV) derivative, ctc-[Pt(NH₃)₂(VPA)(PhB)Cl₂] (cPVP), which combines cisplatin with two KDAC inhibitors, phenylbutyrate and valproic acid. Compared with cisplatin, cPVP induced significantly greater cytotoxicity, and increased DNA damage formation. High-resolution mapping of genomic cisplatin damage and repair indicated that enhanced sensitivity resulted not from altered chromatin accessibility, but from increased drug uptake and the inhibition of NER. Moreover, cPVP prevented the development of resistance to both cisplatin and itself in cancer cells. Together, these results establish the inhibition of nucleotide excision repair, rather than enhanced damage sensitivity due to chromatin accessibility, as the primary mechanism by which KDAC-targeting cisplatin prodrugs overcome resistance to platinum-based therapies. Full article

The cytotoxic effect of islet amyloid polypeptide (IAPP) misfolding and aggregation has a well-recognized role in the pathogenesis of type 2 diabetes mellitus, mediated by failure of the beta cell’s protein quality control system to rescue the cell from overwhelming proteotoxic stress induced by IAPP aggregates, ultimately leading to apoptosis. A small but growing body of research also links IAPP-mediated proteotoxic stress to the pathogenesis of type 1 diabetes and to the functional decline of transplanted islets. Among the most promising therapeutic approaches under investigation are small organic molecules that may act as direct chemical chaperones to prevent IAPP aggregation, promote the activity of endogenous chaperones, or alter gene networks of the unfolded protein response (UPR) to promote pro-survival rather than pro-apoptotic pathways in response to IAPP-mediated proteotoxic stress. Compounds warranting special attention include 4-phenylbutyrate (PBA), tauroursodeoxycholic acid (TUDCA), and epigallocatechin gallate (EGCG), as each has a growing body of evidence supporting their ability to ameliorate this process, and given that each of these are already known to have good safety profiles in humans, potentially accelerating the timeline to interventional studies. This review explores the evidence for IAPP-mediated proteotoxicity in multiple forms of diabetes, the mechanisms of cytotoxicity at different levels of the cell’s protein quality control systems, how these small organic compounds may act on these processes including new insights on the role of thioredoxin-interacting protein (TXNIP), and the current evidence supporting each of these compounds in mitigating diabetogenesis. Full article

Tri-o-cresyl phosphate (TOCP) is widely used as a plasticizer, flame retardant, and lubricant additive, but has been reported to impair spermatogenesis. However, how TOCP affects spermatogenesis remains unclear. Therefore, the objective of this study is to investigate the underlying mechanism by which TOCP disrupts spermatogenesis. In order to achieve this, adult male mice were orally administered TOCP at doses of 0, 200, or 400 mg/kg for two weeks, and we found that TOCP exposure reduced the number of germ cells and decreased sperm density. Moreover, the numbers of PCNA-positive cells and phospho-histone H3 (Ser10)-positive cells in mouse testicular tissues were significantly decreased following TOCP treatment, indicating that germ cell proliferation may be impaired. In addition, TOCP did not affect the protein expression of neuropathy target esterase (NTE) in testicular tissues but markedly inhibited its enzymatic activity (by approximately 30% relative to the control level). In vitro experiments further demonstrate that TOCP suppressed cell proliferation and mitotic progression in mouse GC-1 spg cells and excessively activated endoplasmic reticulum (ER) stress. Treatment with 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, partially reversed the TOCP-induced inhibition of cell proliferation and mitosis. Furthermore, TOCP inhibited NTE activity in GC-1 spg cells, and NTE knockdown produced a phenotype similar to that observed after TOCP exposure, characterized by suppressed cell proliferation and mitotic progression. Surprisingly, ER stress was not activated in GC-1 spg cells following NTE knockdown. Collectively, these findings suggest that TOCP may impair spermatogenesis by inhibiting the proliferation and mitotic progression of mouse germ cells, potentially through mechanisms involving excessive activation of ER stress or suppression of NTE activity. Full article

Backgrounds: Premature ovarian insufficiency (POI) is a clinical syndrome characterized by premature ovarian dysfunction, amenorrhea, and infertility. Ferulic acid (FA) is a prominent bioactive phenolic compound derived from traditional Chinese herbs Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort. These herbs are commonly used to treat gynecological disorders including menstrual irregularities and infertility, and are known to modulate endoplasmic reticulum (ER) stress. However, the therapeutic potential and molecular mechanisms of FA in the context of POI remain largely unexplored. This study aimed to investigate the protective effects of FA against POI and to elucidate the underlying pharmacological mechanisms. Methods: In vivo, a mouse model of POI was established via a single intraperitoneal injection of cyclophosphamide (CTX; 120 mg/kg), and using FA for 28 days of continuous gavage to observe its therapeutic effect. Ovarian function and pathological changes were assessed by hormone levels, follicle development and oxidative stress (OS) level. In vitro, the effects of FA were examined using 4-hydroperoxy cyclophosphamide (4-OHCP)-treated KGN granulosa cells. Transcriptome sequencing, molecular docking, and molecular dynamics simulations were employed to identify potential targets of FA. Results: Our findings demonstrated that FA administration helped preserve regular estrous cycles, promoted follicle development and hormone secretion, and attenuated OS in both ovarian tissue and granulosa cells (GCs). Transcriptomic profiling combined with molecular docking and molecular dynamics simulations suggested that FA potentially targets key ER stress proteins, specifically Grp78 and Perk. Further in vivo and in vitro experiments confirmed that FA alleviates ER stress by inhibiting the overactivation of the Perk/eIF2α/ATF4/CHOP signaling pathway. Notably, the protective effects of FA were comparable to those of the ER stress inhibitor 4-Phenylbutyric acid (4-PBA) and were reversed by the ER stress activator tunicamycin (TM). Additionally, FA downregulates ERO1α expression, further blocking secondary oxidative damage triggered by ER stress. In KGN cells, FA significantly inhibits 4-OHCP-induced apoptosis and upregulates the anti-apoptotic proteins BCL-2 and BCL-xL, exhibiting efficacy similar to 4-PBA. Conclusions: FA improves ovarian function in CTX-induced POI by coordinately regulating OS and ER stress, inhibiting the Perk/eIF2α/ATF4/CHOP pathway, and suppressing GC apoptosis. These findings provide experimental evidence supporting FA as a potential therapeutic candidate for POI. Full article

Bisphenol F (BPF) is a chemical compound that has found extensive application in the field of plastics manufacturing. BPF exposure leads to renal dysfunction; however, the mechanism is unclear. This study investigated BPF-induced nephrotoxicity using 50 male Kunming mice divided into five groups: control (C), low-dose (L, 0.5 mg/kg), medium-dose (M, 5 mg/kg), high-dose (H, 50 mg/kg) BPF, and an intervention group receiving 4-phenylbutyric acid (4-PBA) plus BPF. Treatments were administered daily by oral gavage for 28 days. Renal function was assessed via serum creatinine (SCr), while inflammation and fibrosis were evaluated using histology, immunohistochemistry, immunofluorescence, ELISA, qRT-PCR, and Western blotting. Preliminary results suggest that BPF causes structural damage and dysfunction in the mice kidney. Furthermore, BPF-induced renal inflammation and fibrosis, accompanied by the activation of endoplasmic reticulum (ER) stress and the polarization of renal macrophages toward M1 and M2 types. In vitro, BPF (40 µM, 48 h) induced similar effects in Raw264.7 cells, which were mitigated by 4-PBA pretreatment. Finally, 4-PBA intervention confirmed that BPF triggers macrophage polarization via ER stress, leading to inflammation and fibrosis, ultimately causing renal dysfunction in vivo. This study provides new insights into BPF nephrotoxicity and a basis for therapeutic strategies. Full article

Global climate change has increased the frequency and intensity of heat waves, posing a significant threat to livestock production. During heat exposure, the disruption of intestinal barrier integrity is a pivotal event in the pathogenesis of heat stress-induced intestinal injury. Endoplasmic reticulum (ER) stress and mitochondrial dysfunction are key consequences of heat stress at the cellular level. However, direct causal evidence linking ER stress to mitochondrial dysfunction in heat-stressed enterocytes remains limited. To investigate this, we used an integrated transcriptomic, metabolomic, and functional validation strategy to assess mitochondrial bioenergetics and cellular ultrastructure in porcine intestinal epithelial (IPEC-J2) cells under acute heat stress. Transcriptomic analysis revealed extensive reprogramming, highlighting the significant enrichment of pathways related to protein processing in the endoplasmic reticulum, apoptosis, and MAPK signaling. Untargeted metabolomics identified significant perturbations in amino acid and energy metabolism, as well as altered bile acid profiles. Functional assessments confirmed that heat stress severely impaired mitochondrial bioenergetics, as evidenced by reduced maximal respiration and ATP production, and induced ultrastructural damage to mitochondria. The pharmacological inhibition of ER stress by 4-phenylbutyric acid (4-PBA) significantly attenuated the mitochondrial bioenergetic impairment and ultrastructural damage, whereas ER stress induction recapitulated these defects. We demonstrate that heat stress induces profound transcriptional and metabolic remodeling characterized by ER stress activation, which critically mediates subsequent mitochondrial bioenergetic dysfunction and ultrastructural damage. Our findings suggest that targeting ER stress may represent a promising therapeutic strategy to ameliorate enterocyte mitochondrial dysfunction and mitigate heat stress-induced intestinal injury in livestock. Full article

Diabetic nephropathy (DN) is a serious complication in diabetic patients, leading to kidney dysfunction and ultimately end-stage renal disease. Although several pharmacological agents have been developed, treating DN remains challenging due to its complex and multifaceted pathogenesis. Endoplasmic reticulum (ER) stress plays a crucial role in DN pathology; however, the molecular mechanisms underlying reduced ER stress remain poorly understood. This study investigated the protective effects of 4-phenylbutyrate (4-PBA), an ER stress inhibitor, on DN and the related regulatory molecules through gene expression network analysis. A C57BL/6 mouse model of DN was used in combination with a high-fat diet and streptozotocin after unilateral nephrectomy and treated with 4-PBA by intraperitoneal injection for 6 weeks. The 4-PBA treatment effectively improves DN-induced renal structural and functional abnormalities by reducing albuminuria, podocyte loss, glomerular and tubular injury, and renal inflammation and cell death. These changes induced by 4-PBA were associated with decreased expression of ER stress markers and increased autophagy activities in diabetic kidneys. Importantly, 4-PBA reduced components of the complement C1q pathway, the NADPH oxidase complex, and chemokines, thereby attenuating chronic renal dysfunction. Conclusively, inhibition of ER stress is a promising pharmacological target for treating patients with DN. Full article

Background: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is the most prevalent chronic liver disorder globally. Mazdutide has shown clinical benefits in weight management and metabolic regulation, indicating its potential as a therapeutic agent for MASLD. This study aimed to investigate the efficacy and mechanism of action of Mazdutide against early-stage MASLD. Methods: A MASLD mouse model was induced by a 12-week high-fat diet, followed by a 4-week treatment with subcutaneous Mazdutide (100, 200, or 400 μg/kg). In vitro, a cellular MASLD model was established by treating hepatocytes with 1 mM free fatty acids for 24 h, followed by co-treatment with Mazdutide (10, 20, or 50 nM) or the endoplasmic reticulum (ER) stress inhibitor 4-phenylbutyric acid (4-PBA). Serum and hepatic lipid profiles, liver injury markers, and pro-inflammatory cytokines were quantified. Liver histopathology was assessed by hematoxylin and eosin and Oil Red O staining. Protein expression related to ER stress, inflammation, and lipid metabolism was analyzed by immunohistochemistry and Western blot. Results: Compared with the MASLD model group, Mazdutide treatment significantly ameliorated systemic and hepatic lipid metabolism disorders, reduced liver injury markers and hepatic steatosis, and mitigated inflammation and oxidative stress in MASLD mice and hepatocytes (p < 0.05). Mechanistically, Mazdutide alleviated ER stress by modulating the protein kinase R-like endoplasmic reticulum kinase (PERK) pathway, suppressed the nuclear Factor kappa B (NF-κB)-mediated inflammatory response, and downregulated the expression of key lipogenic regulators including sterol regulatory element-binding protein 1 (SREBP-1), CCAAT/enhancer-binding protein beta (C/EBPβ), and peroxisome proliferator-activated receptor gamma (PPARγ) in both models (p < 0.05). Conclusions: Our findings demonstrate that Mazdutide alleviates hepatic ER stress in MASLD, suppresses inflammatory responses and improved lipid metabolism, which ultimately attenuates disease progression. Full article

Background/Objective: Effective topical delivery of 4-phenylbutyric acid (4-PBA) for arsenical vesicant-induced skin injury requires nanocarrier systems that maintain physicochemical and chemical stability during extended storage. This study systematically evaluated the six-month stability of five 4-PBA-loaded micro/nanoparticulate formulations—chitosan nanoparticles (N31, N35), emulsomes (E2), microsponges (MSs), and PLGA nanoparticles (P1)—to identify lead candidates suitable for field deployment and foam integration. Methods: Formulations were subjected to ICH-accelerated stability testing at 25 °C/60% RH and 40 °C/75% RH, with monthly evaluation of particle size, polydispersity index, zeta potential, drug content by HPLC, and chemical/thermal stability by FTIR and DSC. Results: N31 demonstrated superior colloidal stability, maintaining particle size within acceptable limits at both conditions despite progressive surface charge neutralization. E2 showed consistent drug content retention and preserved chemical integrity, though moderate vesicle fusion occurred. MS underwent complete physical degradation at 40 °C within the first month, while P1 exhibited hydrolytic degradation with substantial drug loss. N35 showed severe aggregation indicating colloidal instability. Conclusions: N31 and E2 emerged as lead candidates: N31 is recommended for field deployment where environmental control is limited, while E2 is suitable for controlled storage settings prioritizing drug loading capacity. Full article

Background: Lewisite, a potent chemical warfare agent, induces rapid and progressive cutaneous damage, necessitating treatment strategies that offer both immediate decontamination and prolonged therapeutic action. This study aimed to develop and evaluate a composite topical formulation comprising 4-phenylbutyric acid (4-PBA)-loaded emulsomes embedded within a foam vehicle to address both aspects of vesicant-induced skin injury intervention. Methods: Emulsomes composed of a stearic acid–cholesterol solid lipid core stabilized by a lecithin shell were prepared via thin film hydration and optimized by varying lipid ratios and drug loading parameters. Formulations were characterized for drug loading, particle size, and zeta potential. Physicochemical compatibility was assessed using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses. Stability was evaluated under accelerated refrigerated (25 °C/60% RH) and room temperature (40 °C/75% RH) conditions. The optimized formulation was incorporated into a foam base and evaluated for decontamination efficiency, drug release kinetics, in vitro permeation, and in vivo efficacy. Results: The selected formulation (E2) exhibited high drug loading (17.01 ± 0.00%), monodisperse particle size (PDI = 0.3 ± 0.07), and stable zeta potential (−40 ± 1.24 mV). FTIR and DSC confirmed successful encapsulation with amorphous drug dispersion. The emulsome-foam demonstrated dual functionality: enhanced decontamination (66.84 ± 1.27%) and sustained release (~30% over 24 h), fitting a Korsmeyer–Peppas model. In vitro permeation showed significantly lower 4-PBA delivery from E2 versus free drug, confirming sustained release, while in vivo studies demonstrated therapeutic efficacy. Conclusions: This emulsome-foam system offers a promising platform for topical treatment of vesicant-induced skin injury by enabling both immediate detoxification and prolonged anti-inflammatory drug delivery. Full article

Perinatal asphyxia (PA) remains a common cause of neonatal death and long-term disability, with an incidence of 20 per 1000 live births. Even mild PA, without significant neurological distress at birth, is linked to neurodevelopmental disorders. Premature babies are at high risk for both PA and long-term neurobehavioral deficits. The use of peripherally inserted central venous catheters in neonatal intensive care units has reduced mortality and morbidity in preterms. Given their prevalent use and associated complications, such as thrombosis, the present study aimed to investigate the effects of hypoxia associated with the ligation of the external jugular vein (JH model) in 5-day-old mice, whose central nervous system development shares similarities with that of human preterms. Diffuse white matter (WM) injury is associated with later neurodisabilities following very premature birth before 32 weeks of gestation. The present study aimed to investigate whether the murine JH model replicates a key phenotype of non-cystic WM injury, namely permanent hypomyelination and sensorimotor deficits. The second aim was to determine whether sodium phenylbutyrate (PBA), which is already prescribed in neonates for another indication, could prevent these disabilities. JH induced lasting dysmyelination in males, not prevented by PBA, contrary to the discrete JH-induced neurobehavioral deficits observed in both sexes in the short and long term. Full article

Previous studies have identified oxidative stress and inflammatory responses in granulosa cells (GCs) of periparturient dairy cows. However, whether non-esterified fatty acids (NEFA)-induced endoplasmic reticulum (ER) stress is involved in GC apoptosis remains unclear. In this study, treatment with NEFA (0.9 mM, 24 h) activated the ER stress pathway. This was evidenced by increased expression of both CHOP and GRP78. Furthermore, upregulation of pro-apoptotic factors BAX and Caspase-3 and downregulation of the anti-apoptotic factor Bcl-2 were observed. Pretreatment of GCs with 4-phenylbutyric acid (4-PBA, 2.5 mM, 2 h) reversed the ER stress and apoptotic effects. This suggests that NEFA-induced apoptosis is mediated through activation of the PERK pathway of ER stress, and that 4-PBA alleviates this effect. Furthermore, targeted metabolomics revealed disruptions in lipid and hormone metabolism in GCs following NEFA treatment. Analysis revealed an increase in the levels of 26 types of fatty acids, while a decrease was detected in the levels of 3 types of fatty acids. In summary, NEFA induces ER stress and disrupts intracellular fatty acid, ultimately leading to cell apoptosis. Our findings offer valuable insights for developing strategies to regulate follicular development in dairy cows and mitigate the impacts of postpartum negative energy balance (NEB). Full article

Background and Objectives: Estrogen deficiency after menopause accelerates bone loss through oxidative stress and inflammatory cytokines. Sodium phenylbutyrate (SP), a histone deacetylase inhibitor, exhibits antioxidative and anti-inflammatory effects, but its impact on postmenopausal osteoporosis remains unclear. Materials and Methods: Thirty female Wistar rats were divided into control, ovariectomy (OVX), and OVX+SPB groups (n = 10 each). After 12 weeks, bone mineral density (BMD), histomorphometry, bone marrow biomarkers (MDA, TNF-α, IL-6, RANKL), and plasma Cathepsin K were evaluated. Results: OVX induced trabecular deterioration with reduced number, area, and thickness (all p < 0.001), increased separation (p < 0.001), and decreased femoral and lumbar BMD (p < 0.001). SPB significantly improved these indices (TN, p < 0.05; TA, p < 0.01; TH, p < 0.05; femoral BMD, p < 0.05; lumbar BMD, p < 0.001; TS, p = 0.001). OVX elevated MDA, TNF-α, IL-6, RANKL, and Cathepsin K (all p < 0.001), which were significantly reduced by SPB (MDA, p < 0.001; TNF-α, p < 0.01; IL-6, p < 0.01; RANKL, p < 0.001; Cathepsin K, p < 0.001). Conclusions: SPB mitigates OVX-induced oxidative stress, inflammatory cytokine release, and osteoclast-mediated resorption, resulting in partial but significant improvements across biochemical, structural, and histomorphometric parameters in estrogen-deficient rats. Given its established clinical safety profile, SPB emerges as a cost-effective candidate for repurposing in postmenopausal osteoporosis, warranting further translational and clinical studies. Full article

Spastic paraplegia 80 (SPG80), caused by mutations in ubiquitin-associated protein 1 (UBAP1), is a pure form of juvenile-onset hereditary spastic paraplegia (HSP) and leads to progressive motor dysfunction. Despite recent advances in the molecular analyses of HSP, disease-modifying therapy has not been established for HSP including SPG80. In the present study, we evaluated the therapeutic potential of 4-phenylbutyric acid (4-PBA), a chemical chaperone and histone deacetylase inhibitor, in Ubap1 knock-in (KI) mice expressing a disease-associated truncated UBAP1 variant. We found that 4-PBA administration significantly improved the motor performance of KI mice in the rotarod and beam walk tests, with maximal benefits achieved when given during pre- or early-symptomatic stages. Partial efficacy was also observed when treatment began after symptom onset in KI mice. Furthermore, 4-PBA attenuated spinal microglial activation and partially restored microglial morphology, although astrocytic reactivity remained unchanged. These findings support 4-PBA as a candidate therapeutic compound for SPG80 and highlight the potential of proteostasis-targeted interventions in HSPs. Full article

Background/Objectives: The accumulation of Nε-carboxymethyllysine (CML), a major advanced glycation end product (AGE), has been implicated in neuronal dysfunction by promoting oxidative stress, endoplasmic reticulum (ER) stress, and dysregulation of amyloid-β (Aβ) metabolism. This study evaluated the neuroprotective properties of coixol, a naturally occurring polyphenolic compound derived from the outer layers of Coix lacryma-jobi L. var. ma-yuen, in a CML-induced injury model using IMR-32 human neuronal-like cells. Methods: Cells were pretreated with coixol (1 μmol/L), N-acetyl-L-cysteine (NALC, 1 mmol/L), or 4-phenylbutyric acid (4-PBA, 200 μmol/L) for 1 h prior to CML (100 μmol/L) exposure for 24 h. Cell viability was determined by colorimetric analysis of 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide, while intracellular reactive oxygen species (ROS) generation was quantified using a fluorescence-based oxidative stress probe. Activities of key antioxidant enzymes and caspase-3 were determined using commercial assay kits. The expression of Aβ isoforms, amyloidogenic enzymes, ER stress markers, and apoptosis-related signaling proteins was quantified through validated immunoassays. Results: Coixol pretreatment significantly enhanced cell viability by attenuating ROS accumulation and restoring antioxidant enzyme activities. Concurrently, coixol suppressed ER stress signaling via downregulation of the protein kinase R-like ER kinase/C/EBP homologous protein axis and modulated apoptosis by increasing B-cell lymphoma (Bcl)-2, reducing Bcl-2-associated X protein expression, and inhibiting caspase-3 activation and DNA fragmentation. Furthermore, coixol regulated Aβ metabolism by inhibiting the expression of β-site amyloid precursor protein-cleaving enzyme 1 and presenilin 1, while restoring insulin-degrading enzyme and neprilysin levels, leading to reduced accumulation of Aβ40 and Aβ42. Conclusions: Compared to NALC and 4-PBA, coixol demonstrated comparable or superior modulation across multiple pathological pathways. These findings highlight coixol’s potential as a neuroprotective candidate in AGE-associated neurodegenerative conditions. Full article