Search Results (2,415)

Bortezomib (BTZ), the first-generation proteasome inhibitor, has been approved for the treatment of relapsed, refractory, and newly diagnosed multiple myeloma. Despite its remarkable antitumor efficacy, BTZ treatment is severely limited by a high incidence of systemic adverse reactions, primarily due to its non-selective cytotoxicity toward rapidly dividing normal cells and its potent neurotoxic effects on peripheral neurons. Bortezomib-induced peripheral neurotoxicity (BIPN) manifests as neuropathic pain and sensory abnormalities, affecting up to 31% to 64% of patients and limiting BTZ’s clinical use. Currently, the underlying mechanisms of BIPN are poorly understood. To evaluate the effects of BTZ on the functions of peripheral nerves in mice, we administered an intraperitoneal injection treatment for four weeks. Results indicated that BIPN caused mechanical allodynia, gait abnormalities, and pathological changes in myelin and axons in mice. This study confirms that BTZ upregulates the expression of the activating transcription factor 3 (ATF3), which in turn mediates the increased expression of the copper transporter SLC31A1, causing dysregulation of intracellular copper ion homeostasis and subsequent copper accumulation, and ultimately inducing the development of peripheral neurotoxicity. Elevated intracellular copper concentration exerts a dual effect: it directly promotes the oligomerization of Dihydrolipoamide S-acetyltransferase (DLAT) and concurrently damages the iron–sulfur cluster protein ferredoxin 1 (FDX1), collectively triggering the onset of cuproptosis. Green tea has garnered attention for its rich content of catechins, with (−)-Epigallocatechin Gallate (EGCG) being the most abundant catechin present. This study uncovers the molecular mechanism by which EGCG inhibits BTZ-induced cuproptosis through targeted regulation of copper homeostasis. Analyses demonstrate that EGCG significantly downregulates the expression of the copper transporter SLC31A1, thereby effectively suppressing transmembrane influx of extracellular copper ions. This intervention markedly reduces intracellular copper overload, eliciting a dual regulatory effect: on one hand, the decreased copper concentration directly inhibits the oligomerization of DLAT; on the other hand, it effectively protects the iron–sulfur cluster protein FDX1 from damage. This study aims to systematically elucidate the molecular mechanisms underlying BIPN and to evaluate the therapeutic potential of EGCG in alleviating BIPN, offering a novel therapeutic strategy for the prevention and treatment of BIPN. Full article

Extracellular vesicles (EVs) from the edible mushroom Pleurotus tuber-regium (PTR) were investigated with respect to their environmental responsiveness, molecular features, and preliminary functional properties. PTR-EVs were characterized by dynamic light scattering, nanoparticle tracking analysis, and transmission electron microscopy. Proteomic analysis revealed enrichment of ribosomal and proteasomal proteins, redox-related enzymes, and vesicle trafficking components, suggesting non-random molecular representation. Small RNA sequencing identified abundant novel miRNAs with predicted targets involved in nitrogen metabolism, cell wall remodeling, redox regulation, and ubiquitin-mediated proteolysis. Among the tested factors, temperature showed the strongest association with vesicle production, with particle concentration increasing from 1.22 × 10⁹ to 7.31 × 10⁹ particles/mL at 34 °C, approximately six-fold higher than at 30 °C. Transcriptomic profiling showed coordinated repression of cell wall-associated genes and redox enzymes, together with induction of endoplasmic reticulum proteostasis pathways, consistent with stress-associated changes in the cellular context of vesicle release. Ultrasonicated PTR-EVs exhibited enhanced DPPH and ABTS radical-scavenging activities in chemical assays, with DPPH increasing from 59.52% to 71.73% and ABTS from 38.25% to 40.51%. Encapsulation efficiencies reached 32.67% ± 1.3% for proanthocyanidins and 46.01% ± 0.5% for curcumin. PTR-EVs showed the best short-term stability at pH 7 and 4 °C, supporting their further evaluation as an edible fungal vesicle platform for food-related nanoscale delivery. Full article

Background/Objectives: MYC-driven tumors exhibit significant glutamine addiction, but the metabolic adaptation mechanisms enabling their survival under glutamine deprivation remain incompletely understood. Malic enzymes catalyze the oxidative decarboxylation of malate to pyruvate while generating NADPH, linking central carbon metabolism to redox homeostasis. This study investigates whether and how ME1 and ME2 mediate cell adaptation to glutamine starvation and explores their functional division in relation to p53 status. Methods: Using MYC-amplified, p53-mutant (G266E) SF188 glioblastoma cells, we performed siRNA-mediated knockdown, overexpression, and rescue experiments. Cell survival was assessed by trypan blue exclusion and Annexin V/PI staining. ROS levels and NADP⁺/NADPH ratios were measured by DCFH-DA fluorescence and enzymatic assays. Metabolite tracing was conducted using [U-¹³C₅] glutamine followed by LC-MS. Key findings were validated in additional cell lines including HCT116, U2OS and MDA-MB-231. Results: ME1 and ME2 promote SF188 cell survival under glutamine deprivation, an effect that depends on their catalytic activity but is independent of TCA cycle anaplerosis. ME1 maintains redox balance by generating NADPH, and antioxidant treatment rescues the survival defect caused by ME1 knockdown. In contrast, ME2 does not contribute to redox regulation but stabilizes mutant p53 (G266E) via proteasome inhibition. Both of these pro-survival functions are attenuated upon MYC knockdown, suggesting a dependency on MYC expression. Across all cell lines tested, ME1 and ME2 also promote survival through redox maintenance, although the isoform responsible for antioxidant function differs. Conclusions: ME1 and ME2 support metabolic adaptation to glutamine starvation through distinct, isoform-specific mechanisms that depend on MYC expression and p53 mutation status. These findings suggest malic enzymes as potential therapeutic targets in MYC-driven, p53-mutant tumors. Full article

Betaine-homocysteine methyltransferase (BHMT) is an enzyme involved in one-carbon metabolism and plays a crucial role in maintaining liver health. In this study, we investigated the impact of liver-specific deletion of BHMT on liver dysfunction using a mouse model. We generated BHMT floxed mice and bred them with albumin Cre to generate liver-specific BHMT knockout (BHMT LKO) mice. Liver tissues harvested from six-month-old chow-fed BHMT floxed and LKO mice were characterized through histological, biochemical, and molecular analyses. BHMT LKO mice displayed a complete loss of hepatic expression of BHMT mRNA, protein and enzyme activity. Histopathological analysis revealed the development of hepatic steatosis in BHMT LKO mice compared to the floxed mice. These morphological changes were supported by biochemical analysis showing elevated levels of hepatic triglycerides in conjunction with a profound decrease in the methylation potential (i.e., reduced S-adenosylmethionine (SAM): S-adenosylhomocysteine (SAH) ratio), which was mainly driven by a six- to sevenfold increase in SAH levels. BHMT LKO mice also exhibited increased lipid peroxidation and lysosomal dysfunction compared to floxed mice. Early signs of inflammation were seen in the livers of BHMT LKO mice of both sexes, as evident from significant increase in CD68-positive cells and interleukin 1β levels. Additionally, there was a moderate increase in fibrosis, as evidenced by the upregulated expression of α-smooth muscle actin and collagen II levels and the histological assessment of picrosirius red-stained liver sections of BHMT LKO mice of both sexes compared to their respective counterparts. These findings demonstrate that hepatic BHMT deficiency promotes lipid accumulation, lysosomal/proteasomal dysfunction, and early inflammatory and fibrotic changes in the liver by reducing the methylation potential. Collectively, our results underscore BHMT as a critical regulator of liver homeostasis and a potential therapeutic target in liver-related disorders. Full article

The present study investigated the effect of Ligula intestinalis L. infection on several components of the antioxidant system and on protein oxidation in the host fish, common bream Abramis brama L. In ligulosed bream, the hepatopancreatic antioxidant system response included a decrease in catalase (CAT) activity, an increase in glutathione S-transferase (GST) activity, and no change in superoxide dismutase (SOD) activity. The contents of molecular antioxidants in the organs of infected bream were inconsistent; for instance, hepatopancreatic α-tocopherol content was significantly lower, whereas retinol content was significantly higher than in uninfected individuals. In contrast, no significant differences were found in the α-tocopherol or retinol content in the skeletal muscles of infected and uninfected fish. The protein oxidation, estimated via protein carbonyl content, was unaffected by ligulosis, as was the activity of proteasomes. However, the activity of calpain, another protease, was significantly higher in the skeletal muscle of infected fish. Overall, the data reveal moderate and tissue-specific alterations in oxidative stress markers in A. brama infected with L. intestinalis, suggesting a complex host–parasite interaction that does not result in severe systemic oxidative damage under the studied conditions. Full article

Background: Idiopathic inflammatory myopathies (IIMs), characterized by muscle weakness and chronic inflammation, currently lack highly effective therapies. This study investigated the therapeutic potential and underlying mechanism of (5R)-5-hydroxytriptolide (LLDT-8), a triptolide derivative with reduced toxicity, using an experimental autoimmune myositis (EAM) mouse model and in vitro assays. Methods: Forty female BALB/c mice were randomly assigned to five groups: normal, vehicle, methylprednisolone (MP), LLDT-8 (0.0625 mg/kg), and LLDT-8 (0.125 mg/kg). EAM mice were treated with LLDT-8 (0.0625 or 0.125 mg/kg) or methylprednisolone as a positive control. Cellular experiments and molecular docking were performed to investigate potential mechanisms of LLDT-8. Results: LLDT-8 significantly attenuated clinicopathological features, including muscle weakness and pain sensitivity, while reducing serum levels of aspartate aminotransferase and lactate dehydrogenase. Histological analysis revealed that LLDT-8 reduced inflammatory cell infiltration and the presence of CD4⁺ and CD8⁺ T cells in muscle tissues. Mechanistically, LLDT-8 inhibited the expression of nucleotide-binding oligomerization domain receptor caspase recruitment domain 5 (NLRC5), a key transcriptional regulator of major histocompatibility complex-I (MHC-I). This suppression extended to downstream antigen presentation-related molecules, including the transporter associated with antigen processing and proteasome 20S subunit beta. Molecular docking further confirmed the high binding affinity of LLDT-8 to both NLRC5 and MHC-I. Conclusions: LLDT-8 alleviates inflammatory muscle injury by targeting the NLRC5/MHC-I signaling axis, suggesting it may be a promising therapeutic candidate for IIMs. Full article

While the detrimental effects of high temperature stress on fish growth and disease resistance have been widely reported, its impact on muscle quality has received limited attention. In this study, largemouth bass Micropterus salmoides with an initial body weight of 45.73 g were subjected to a 60-day growth trial (~25 °C), followed by a 5-day acute warming phase and a subsequent 30-day chronic high temperature exposure (32 °C). Through integrated analyses of morphological parameters, texture characteristics, TUNEL assay, gene expression analysis, and metabolomics in muscle, the effects of high temperature stress on the meat quality of largemouth bass were systematically examined. The results showed that high temperature stress significantly upregulated key genes in the ubiquitin-proteasome pathway (trim13, foxo1α) and key genes in the autophagy-lysosome pathways (lc3α, lc3β, bcl2l1, ctsl2), induced apoptosis in muscle cells, and led to significant reductions in myofiber diameter and density. In terms of textural properties, high temperature stress significantly decreased parameters such as springiness, adhesiveness, and cohesiveness, as well as water holding capacity. Metabolomic analysis further revealed that high temperature induced remodeling of energy metabolism and significant reprogramming of purine and amino acid metabolic pathways, resulting in decreased levels of key flavor compounds, including IMP, GMP, flavor amino acids (glutamic acid, alanine, methionine, arginine, proline), and peptides (glu-glu-lys and glu-cys-gly), thereby adversely affecting muscle flavor quality. The findings of this study provide a theoretical basis for understanding the impact of thermal stress on the eating quality of farmed fish. Full article

Euonymus bungeanus is a highly valued ornamental tree/shrub species widely utilized in landscaping and afforestation in Northeast Asia, yet molecular studies on this species remain limited due to the lack of validated reference genes for reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). In this study, 16 candidate reference genes were selected based on classical plant reference genes and our previous transcriptome data. Their expression stability was comprehensively evaluated using 64 samples collected from diverse tissues and plants subjected to various abiotic stress/hormone treatments across multiple time points. Across all samples analyzed, PBG1 (20S proteasome beta subunit G1) exhibited the highest overall expression stability, followed by VAPD (vacuolar ATP synthase subunit D) and EIF4A (eukaryotic translation initiation factor 4A). For tissue-specific analysis, TSR2 (pre-rRNA-processing protein), VAPD, and PBG1 demonstrated the greatest stability. Under specific stress conditions, PBG1 and EIF4A were identified as the most stable genes under low- and high-temperature conditions. PP2A (protein phosphatase 2A) and TUB6 (beta-6 tubulin) were optimal for drought stress, while TSR2, SRP (nuclear speckle splicing regulatory-like protein), and PBG1 exhibited superior stability under salt stress. These findings establish a validated panel of reference genes enabling accurate and reliable gene expression normalization in E. bungeanus, thereby facilitating future functional genomics studies in this economically and ecologically important species. Full article

Although LRRK2 mutations modulate systemic glucose homeostasis and metabolic dysfunction precedes Parkinson’s disease (PD) motor symptoms; the way in which pathogenic variants of LRRK2 disrupt astrocytic glucose metabolism and organellar homeostasis remains poorly understood. Here, we demonstrate that LRRK2-I1371V mutation causes profound metabolic and organellar dysfunction in LRRK2-I1371V PD-iPSC-derived astrocytes and U87 cells overexpressing I1371V variant. LRRK2-I1371V astrocytes exhibit significantly reduced GLUT1 expression and cell surface localization, resulting in impaired glucose uptake and decreased lactate production. This metabolic insufficiency correlates with cascading mitochondrial dysfunction, characterized by membrane depolarization, elevated reactive oxygen species, enhanced ubiquitination and reduced proteasomal activity. Reduced LAMP1/LAMP2 expression, impaired lysosomal acidification, and selective cathepsin D deficiency were observed. Accumulation of undegraded cargo was confirmed by transmission electron microscopy upon α-synuclein exposure. ER stress was evident by upregulation of GADD34/CHOP, increased phospho-PERK, and reduced nascent protein synthesis. Increased ER–mitochondrial contact via MAMs and enhanced STIM1-ORAI3 clustering reflect compensatory but ultimately insufficient responses to energy stress. Our results reveal that LRRK2-I1371V induces glucose uptake deficits, leading to energy depletion and integrated ER–mitochondria–lysosome dysfunction, thus indicating restoration of astrocytic metabolic capacity as a potential therapeutic strategy for LRRK2-associated PD. Full article

Cellular protein quality control comprises the ubiquitin proteasome system, autophagy, and molecular chaperones, which maintain proteostasis in healthy tissues. The failure of these cellular and molecular pathways, which normally safeguard the proteome, can cause and even exacerbate amyloidoses, the abnormal accumulation of proteins into amyloid fibrils that drive neurodegeneration. Amyloidoses can also damage peripheral organs; examples include light chain amyloidosis, cardiac amyloidosis, and renal amyloidosis. Restoring proteostasis and preventing protein aggregation is therefore an active area of research, with several promising strategies under investigation. Among these approaches, small-molecule modulators that restore proteostasis are attractive candidates because they may simultaneously rescue multiple quality control mechanisms and remodel aggregates to improve their accessibility to endogenous degradation pathways. Here, we propose that amyloid pathology disrupts multiple proteostasis pathways simultaneously, creating a feedforward cascade in which the breakdown of interconnected proteostasis networks drives progressive protein aggregation, which in turn propels proteostasis collapse. Pharmacological interventions targeting protein aggregation offer opportunity to rescue interconnected proteostasis networks, which could, in turn, cooperatively manage or eliminate pathogenic amyloid burden. Full article

The gut microbiota, acting as a critical extrinsic endocrine organ, is profoundly involved in the pathological evolution and therapeutic response of hormone-dependent malignancies. This review elucidates the core mechanisms governing the microbiota, endocrine, and immune triple-axis. Multi-omic and biochemical evidence demonstrates that microbial metabolic networks, comprising the estrobolome, androbolome, and progestobolome/corticobolome, rely on enzymatic systems such as β-glucuronidases (GUS) and steroid-17,20-desmolases to execute hormone deconjugation and structural modification, thereby modulating systemic steroid exposure. Concurrently, microbe-derived metabolites, such as secondary bile acids and purine derivatives, act as inter-kingdom messengers. These metabolites remodel the tumor immune microenvironment by antagonizing hormone receptors and activating specific signaling axes, such as the Inosine-A2AR pathway. By modulating localized immune cells like effector T cells and myeloid cells, they play a pivotal role in tumor immune evasion. Furthermore, pharmacomicrobiomics reveals a bidirectional regulation between anti-tumor agents and the gut microbiota, where endocrine and immunotherapeutic drugs can induce microbial dysbiosis, while specific gut taxa contribute to primary or acquired resistance by enzymatically inactivating drugs (e.g., reductive inactivation of Enzalutamide) or providing hormonal precursors through bypass pathways. Facing translational challenges, such as real-world microbiome complexity and the colonization resistance of indigenous flora, we propose treating the human body as a unified host–microbe holobiont system. Future research should leverage gnotobiotic models and genetic causal inference to establish functional causality. These efforts will facilitate the development of precision tools, including ubiquitin–proteasome system (UPS) modulators, microbial enzyme inhibitors, and engineered live biotherapeutics. Collectively, these systems biology strategies offer a robust framework for overcoming therapeutic resistance in hormone-dependent malignancies. Full article

Background: Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. Changes in the ubiquitination system in GBM cells can promote uncontrolled tumor growth and reduce the effectiveness of treatments. However, the exact targets and regulatory elements of the ubiquitin–proteasome system involved in GBM are still not well understood. Methods: All data were obtained by using in silico analysis, immunohistochemistry, Western blot, RT-qPCR, gene silencing and proliferation assay. Results: Computational and protein analyses show that aggressive gliomas have higher expression of the RING ligase RNF182, with significantly greater levels in glioblastoma (GBM) than in low-grade gliomas. Elevated RNF182 is strongly associated with GBM growth. Experiments using siRNA to inhibit RNF182 in the human glioblastoma cell line U87MG significantly reduced cell proliferation, suggesting that RNF182 promotes tumor growth and may be a potential therapeutic target. Conclusions: These findings create a connection between the ubiquitin–proteasome system and the unchecked growth observed in GBM, identifying RNF182 as a new marker associated with GBM proliferation and an additional target for GBM treatment. Full article

Ubiquitination is a reversible post-translational modification crucial for cellular homeostasis and protein degradation. It is orchestrated by a cascade of ubiquitin-activating enzymes (E1), conjugating enzymes (E2), and ligases (E3) that tag proteins with ubiquitin, and deubiquitinating enzymes (DUBs) that remove these tags. Through this tightly regulated ubiquitination/deubiquitination system, cells control protein turnover, localization, and activity, thereby governing processes ranging from cell cycle progression and DNA repair to immune and stress responses. Here, we review the structural and functional mechanisms of each class of enzymes in the ubiquitin–proteasome system, including E1, E2, E3, and DUBs, and highlight their roles in key signaling pathways and physiological processes. We further discuss how the dysregulation of these enzymes leads to diseases such as cancer, neurodegenerative disorders, and immune diseases, underlining the potential of targeting ubiquitination pathways for therapeutic intervention. Full article

Background/Objectives: EBV is an oncogenic virus linked to NPC and GC, driving cisplatin resistance. Resveratrol has anticancer activity, but its targets and mechanisms against EBV-positive cancers remain unclear. Methods: We assessed resveratrol’s cytotoxicity in EBV-positive cells via functional assays, identified targets by chemical similarity search and molecular docking, and validated PTPN1 via in vitro experiments and nude mouse xenograft models. Results: Resveratrol inhibited EBV-positive cell viability in a time- and concentration- dependent manner, with IC50 values ranging from 35.85 to 145.7 μM across different cell lines at 24–72 h. Apoptosis rates increased by approximately 2- to 4-fold after 80 μM resveratrol treatment for 24 h. Resveratrol directly targeted PTPN1 (docking score = −4.89) and promoted its degradation via the proteasome pathway, as MG132 reversed this effect. Notably, resveratrol synergized with cisplatin (combination index < 1) to reverse cisplatin resistance in both in vitro and in vivo models. Furthermore, resveratrol induced EBV lytic reactivation through ROS production, as evidenced by the increased expression of BZLF1, BMRF1, and BALF2, which was attenuated by the ROS scavenger NAC. Conclusions: Our findings identify PTPN1 as a direct anticancer target of resveratrol in EBV-positive cancers. Resveratrol enhances the therapeutic efficacy of cisplatin via PTPN1 proteasomal degradation and induces EBV lytic reactivation through ROS accumulation. These findings provide a mechanistic basis for the development of novel combination therapies targeting EBV-associated malignancies. Full article

Intracerebral hemorrhage induces severe secondary brain injury characterized by excessive neuroinflammation and inefficient hematoma clearance, processes largely governed by microglial polarization and phagocytic activity. The immunoproteasome, an inducible proteasome isoform involved in immune regulation, has been implicated in inflammatory neurological disorders, but its role in microglial responses after ICH remains unclear. In this study, rat models of common hemorrhage, severe hemorrhage, and severe hemorrhage with hematoma aspiration were used to represent graded injury severity and post-evacuation recovery. Transcriptomic profiling at day 3 post-injury identified immunoproteasome-associated gene networks, while expression of the catalytic subunits LMP2 and LMP7, microglial polarization markers, and phagocytic receptors was analyzed by Western blotting and immunofluorescence. Severe hemorrhage markedly induced LMP2 and LMP7 expression, predominantly in Iba1⁺ microglia, accompanied by enhanced ER stress, NF-κB signaling, and M1-like polarization and reduced phagocytic marker expression. Hematoma aspiration attenuated immunoproteasome expression and restored M2-associated and phagocytic signatures. Consistently, pharmacological inhibition of immunoproteasomes in primary microglia enhanced erythrophagocytosis and promoted a reparative phenotype in vitro. These findings indicate that immunoproteasome activation links hemorrhagic severity to maladaptive microglial polarization and impaired hematoma clearance after ICH, and that reducing immunoproteasome expression may help rebalance inflammatory and phagocytic microglial functions. Full article