搜索结果：Biochimica et biophysica acta. Molecular basis of disease

Circulating tumor cell (CTC) clusters are potent mediators of metastasis, exhibiting dramatically enhanced survival and colonization potential compared to single CTCs. However, the molecular and metabolic programs that initiate cluster formation remain poorly defined. CD36 is known to be critical for metastasis and metabolism. However, its regulatory role during the Adherent-to-Suspension Transition (AST) and subsequent CTC clustering remains unclear. This study aimed to elucidate how CD36 orchestrates early clustering of AST-derived cancer cells and to explore its potential as a stage-specific therapeutic vulnerability. We utilized an in vitro AST-Cluster Transition Model with cancer cells, monitored by live-cell imaging. The impact of CD36, glycolysis, and ROS inhibition on cluster dynamics and viability was assessed. Efficacy was confirmed in vivo using a cluster-driven metastasis mouse model and patient data (CTC transcriptomes, METABRIC cohort) were analyzed for metabolic and prognostic relevance. We found biphasic CD36 expression (upregulated in AST cells, decreased upon clustering) concurrent with a metabolic shift from OXPHOS to glycolysis under hypoxia. This metabolic reprogramming was sustained by the AKT, AMPK, and HIF1α axes. CD36 inhibition impaired early cluster formation, which was accompanied by decreased expression of junctional proteins, and was sufficient to reduce cluster-driven lung metastases in vivo. Patient data linked similar metabolic remodeling signatures, and high expression of CD36 and JUP was associated with poorer early survival. This study identifies CD36 as a dynamic regulator linking AST to clustering and metabolic adaptation. CD36 blockade effectively suppresses cluster-driven colonization, revealing CD36 as a tractable, stage-specific therapeutic target to intercept metastatic dissemination at its earliest, most vulnerable stage.

As the most aggressive form of breast cancer, triple-negative breast cancer (TNBC) is associated with poor prognosis and a lack of effective therapeutic options. Glycosylation has been linked to metabolic reprogramming in various cancers, and therapies targeting glycosylation-mediated metabolic reprogramming have been found to be effective. However, the role of the glycosyltransferase GALNT6 in TNBC metabolic reprogramming has not been examined. Our approach involved analyzing clinical data to assess the association between GALNT6 levels and patient outcomes. We employed gene knockdown techniques to silence GALNT6 expression in TNBC models. To investigate the underlying mechanisms, we utilized methods to measure glycolytic activity, metabolite levels, protein stability assays, transcriptional analysis, and assessment of DNA methylation status. Our results revealed that high level of GALNT6 were associated with poor clinical outcomes in TNBC. GALNT6 knockdown inhibited glycolytic and enhanced α-KG accumulation. Mechanistically, GALNT6 stabilizes HIF-1α through O-glycosylation, thereby enhancing the transcriptional levels of glycolytic enzymes. Meanwhile, GALNT6 stabilizes PFKM and PKM2 via O-glycosylation to protect them from proteasomal degradation. In parallel, GALNT6 promotes α-KG depletion by upregulating IDH2 and α-KGDH while suppressing GPT2. This depletion inhibits TET3-mediated DNA demethylation, thereby elevating 5mC levels, which in turn activates genes such as KIF14 to promote TNBC progression. Notably, silencing glycosylation-dependent glycolytic pathways or inhibiting α-KG-dependent processes markedly suppressed TNBC proliferation. Our study uncovers GALNT6 as a key regulator of metabolic reprogramming (glycolysis/TCA cycle) and epigenetic remodeling (5mC/TET3) to accelerate TNBC progression, suggesting that targeting the GALNT6-mediated metabolic-epigenetic axis may provide a novel therapeutic strategy for TNBC.

Liver fibrosis (LF) is an abnormal repair reaction after chronic liver injury. Currently, adipose-derived mesenchymal stem cells (ADSCs) are widely used in the treatment of liver diseases. However, the therapeutic effect of ADSCs is affected by the damaged microenvironment. In this study, a resveratrol-functionalized nano‑selenium (Res@SeNPs) formulation was prepared to investigate whether Res@SeNPs pretreatment can enhance the therapeutic effect and alter the potential mechanism of ADSCs in carbon tetrachloride (CCl4) -induced LF in mice. Res@SeNPs were prepared and ADSCs pretreated with Res@SeNPs were cocultured with CCl4-injured BRL-3A cells in vitro. In vivo, ADSCs pretreated with Res@SeNPs were injected into the tail vein of a CCl4-induced LF mouse model. Res@SeNPs were successfully prepared. In vitro, after coculture with BRL-3A cells, the function of damaged BRL-3A cells was improved. In vivo, Res@SeNPs-pretreated ADSCs effectively alleviated liver function damage and fibrosis in mice with LF. This may be related to the inhibition of oxidative stress, the reduction in apoptosis and the inhibition of the activation of the apoptosis signal-regulated kinase 1/c-Jun N-terminal kinase/p38 mitogen-activated protein kinase (ASK1/JNK/p38) pathway. Our study suggested that Res@SeNPs pretreatment can enhance the therapeutic effect of ADSCs on LF in mice, and in vivo findings indicated the potential mechanism of ADSCs, providing new ideas for the treatment of LF.

Gemcitabine (Gem), a primary treatment for advanced and metastatic bladder cancer, can lead to malignant progression and drug resistance, though the underlying mechanisms are not fully understood. Post-translational modifications (PTMs) are key to understanding this resistance and identifying new chemosensitizers. To decipher the relationship between the PTM and Gem-induced chemotherapy resistance in bladder cancer, a Gem-resistant cell line was developed from Gem-sensitive cells through repeated exposure to the drug, revealing increased levels of acetylation and O-GlcNAcylation compared to the parent cells. Thereafter, considering the significant role of histone acetylation in gene regulation, the histone acetyltransferase inhibitor C646 was employed to inhibit growth of Gem-resistant bladder cancer cells. Intriguingly, C646 was found to prevent the progression of Gem-resistant bladder cancer not only by inhibiting acetylation but also O-GlcNAcylation modifications both in vitro and in vivo. Immunohistochemistry analysis of bladder cancer clinical specimens confirmed that both histone H3 lysine 27 acetylation (H3K27ac) and O-GlcNAc transferase (OGT) expression levels were elevated post-chemotherapy and positively correlated. Further, chromatin immunoprecipitation followed by quantitative reverse transcription polymerase chain reaction (ChIP-qPCR) demonstrated that H3K27ac influences OGT expression by binding to its promoter region. Additionally, C646 disrupted OGT-mediated O-GlcNAcylation by suppressing the acetylation of H3K27 and its accumulation on the OGT promoter, thereby inhibiting Gem-resistant bladder cancer growth. Consequently, targeting the H3K27ac/OGT axis with histone acetyltransferase inhibitor offers a promising strategy to overcome Gem resistance in bladder cancer.

Ceroid lipofuscinosis neuronal 5 (CLN5) disease is a subtype of neuronal ceroid lipofuscinosis (NCL, commonly known as Batten disease) that is caused by mutations in the CLN5 gene. While 70 distinct CLN5 disease-causing mutations have been documented, the pathological effects of these mutations are largely unknown. In this study, we used the model eukaryote Dictyostelium discoideum to examine the molecular and cellular effects of five CLN5 disease-causing mutations (p.Cys77Tyr, p.Trp158Ser, p.Tyr209Asp, p.Glu303*, and p.Tyr343*). We used informatics tools to show that the five mutations alter the predicted structure of the protein. We then introduced these mutations into Dictyostelium Cln5 and examined their effects on the localization and secretion of the protein, as well as proteostasis and lysosomal activity. We observed that the mutations alter the cellular distribution of Cln5 and intracellular catabolic mechanisms, including 20S proteasome-mediated protein degradation and lysosomal enzyme-mediated breakdown. The mutations also affect vesicles within the endo-lysosome pathway and the release of Cln5 and other lysosomal enzymes from cells, which impacts extracellular enzyme activity. Finally, while cell proliferation and aggregation are not affected by mutated Cln5, loss of the signal peptide in Cln5 delays aggregation, supporting an extracellular role for the protein. This study, which is the first to comprehensively examine the effects of the p.Cys77Tyr, p.Trp158Ser, p.Tyr209Asp, p.Glu303*, and p.Tyr343* mutations on cellular function, enhances our understanding of the effects of mutations in CLN5 on endo-lysosomal trafficking and lysosomal biology, as well as the pathological mechanisms underlying CLN5 disease.

Diabetic kidney disease (DKD) is one of the most severe microvascular complications of diabetes, with proximal tubular (PT) epithelial cells playing a pivotal role in its progression, yet the underlying dynamic molecular mechanisms remain unclear. In this study, single-cell transcriptomic dataset GSE183276 and bulk RNA-seq dataset GSE30122 were integrated to systematically analyze the heterogeneity and functional alterations of PT epithelial cells in DKD. PT epithelial cells were classified into three subpopulations: PT-Homeostatic, PT-Transitional and PT-Stressed. In DKD, the PT-Homeostatic subpopulation decreased markedly, whereas PT-Transitional and PT-Stressed subpopulations increased significantly. Functional enrichment analyses revealed that PT-Homeostatic cells mainly participated in amino acid and fatty acid metabolism; PT-Transitional cells were enriched in wound repair, Wnt signaling and oxidative stress response; PT-Stressed cells were associated with fibroblast proliferation, anti-apoptosis and chemotaxis regulation. Pseudotime analysis indicated that PTECs gradually shift from a homeostatic to a stressed phenotype during DKD progression. Eight core downregulated genes were further screened, among which HPGD and G6PC were specifically highly expressed in PT-Homeostatic cells and significantly downregulated in DKD. In vitro experiments demonstrated that high glucose repressed transcription factor RXRA expression to further reduce G6PC transcription. RXRA overexpression restored G6PC levels, inhibited pro-inflammatory and fibrotic markers, and upregulated E-cadherin, while G6PC knockdown reversed these protective effects. Collectively, this study uncovered the dynamic phenotypic transition of PTECs in DKD and identified the RXRA-G6PC axis as a potential therapeutic target.

Metabolic dysfunction-associated steatotic liver disease (MASLD) increases the risk of developing steatohepatitis, liver cirrhosis, and liver cancer. Neddylation, a ubiquitin-like post-translational modification, has been proven to play a crucial role in disease progression. Here, we demonstrate that the dysregulation of neddylation is a critical aggravator of MASLD. Treatment with the neddylation inhibitor MLN4924 effectively reduced lipid accumulation and modulated the JAK-STAT signaling pathway by attenuating upstream inflammatory cytokines. Mechanistically, we identified the signal transducer and activator of transcription 3 (STAT3) as a direct neddylation substrate. Our data indicate that neddylation might be essential for acetylation-induced STAT3 dimerization. However, blocking neddylation with MLN4924 concurrently led to the stabilization of CRL-dependent downstream targets, affecting cell cycle and survival pathways. Given the complex and dynamic role of STAT3 in MASLD progression, we further found that combining MLN4924 with a specific STAT3 inhibitor synergistically blocked fatty acid uptake and modulated lipid homeostasis. Overall, our findings uncover a novel regulatory network involving neddylation dysregulation during MASLD progression and highlight the combination of neddylation and STAT3 inhibition as a promising therapeutic strategy.

The N-6-methyladenosine (m6A) modification of mRNA regulates transcript abundance in endocrine therapy (ET)-resistant breast cancer (BCa) cells. We reported that m6A reader HNRNPA2B1 decreased miR-145p and miR-424-5p targeting PSAT1 and miR-34b-5p and miR-876-5p targeting PHGDH, thus stimulating the serine synthesis pathway (SSP) in ET-resistant BCa cells. Here we examined m6A regulation of PSAT1 and PHGDH. We report that siMETTL3 increased miR-145-5p, reducing PSAT1, and miR-34b-5p and miR-876-5p, reducing PHGDH, without affecting HNRNPA2B1 or NFkB and decreasing MYC, known to stimulate PSAT1 and PHGDH transcription. In contrast, the METTL3 inhibitor STM2457 increased METTL3, MYC, HNRNPA2B1, NFkB, PSAT1, PHGDH, and serine synthesis, and decreased the miRNAs. These data suggest that reducing METTL3 protein and inhibition of its catalytic activity have different effects on these targets. Selected results were verified in ET-resistant T47D and ZR-75-1 BCa cells. METTL3's stimulation of translation may play a role in these differences. Indeed, siMETTL3 had no effect on MYC, PHGDH, or PSAT1 pre-mRNA whereas STM2457 increased these pre-mRNAs. Overall, our data support a model for m6A regulation of PHGDH and PSAT1 indirectly through miRNAs that target PHGDH and PSAT1.

Systemic lupus erythematosus (SLE) and autoimmune hepatitis (AIH) are clinically distinct autoimmune disorders characterized by multisystem involvement and liver-restricted inflammation, respectively; nevertheless, they exhibit considerable overlap in their underlying immunopathogenic features. To provide a systematic synthesis of recent advances in genetics, immunology, and microbiome science, and to delineate the convergent pathogenic mechanisms that underpin both SLE and AIH. A comprehensive literature review was conducted using PubMed and other databases up to 2025, focusing on shared genetic, cellular, and microbial determinants in SLE and AIH. Core topics included genetic susceptibility loci, breakdown of immune tolerance, T-cell dysregulation, innate immune activation, and alterations in gut microbiota composition and function. SLE and AIH share several genetic risk variants, including HLA-DRB1*03:01, PTPN22, STAT4, and TNFAIP3. Both diseases are characterized by defective central and peripheral immune tolerance, imbalances in Th17/Treg and Tfh/Tfr compartments, and aberrant B-cell activation. Innate immune pathways-encompassing Toll-like receptor and NLRP3 inflammasome signaling as well as complement dysregulation-further amplify inflammation. Moreover, gut dysbiosis and perturbations in microbial metabolites, such as short-chain fatty acids, bile acids, and tryptophan derivatives, function as key mediators linking intestinal homeostasis to both systemic and hepatic autoimmunity. SLE and AIH represent overlapping entities along a unified autoimmune spectrum, driven by shared genetic susceptibility, convergent immune dysregulation, and microbial influences. This review advances an integrated immunological framework that bridges systemic and organ-specific autoimmunity, underscores the pivotal role of innate immunity and gut-liver crosstalk, and provides a mechanistic rationale for cross-disease therapeutic strategies targeting these common pathways.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy globally, characterized by high invasiveness and poor prognosis. Over half of patients experience recurrence or metastasis within three years, underscoring the limitations of current therapies, especially in inoperable cases, and emphasizing the need to elucidate molecular mechanisms driving its aggressiveness. This study investigates the tumor-suppressive role of HAO2 in the context of dysregulated lipid metabolism and HNSCC pathogenesis. Using an integrated approach, we combined bioinformatic analyses, cellular models, and in vivo experiments to comprehensively evaluate HAO2 expression and functional significance in HNSCC. This included assays to assess proliferation, invasion, migration, and mechanistic interactions involving ubiquitination pathways. HAO2 is significantly downregulated in HNSCC, and its overexpression suppresses tumor growth and modulates lipid metabolism. Expression inversely correlates with key lipid metabolic pathways, suggesting its therapeutic potential in metabolic reprogramming. Clinically, low HAO2 expression correlates with poorer patient survival, supporting its utility as a prognostic biomarker. Functional assays confirm that HAO2 inhibits proliferation, invasion, and migration. Mechanistically, HAO2 promotes ubiquitin-mediated degradation of MYH9 by enhancing its association with the E3 ubiquitin ligase STUB1 and impairing interaction with the deubiquitinating enzyme USP14, collectively enhancing MYH9 ubiquitination and degradation. Our findings unveil the HAO2/STUB1/USP14/MYH9 axis as a pivotal regulatory pathway in HNSCC, providing a mechanistic foundation for clinical translation. These results underscore the potential of HAO2 as a prognostic marker and warrant further clinical validation and investigation into its role in other cancers.

Testis-specific protease 50 (TSP50), a tumor-associated antigen with minimal expression in normal tissues, emerges as a promising therapeutic target. In this study, we report its aberrant overexpression and proliferation-promoting role in skin cutaneous melanoma (SKCM). Using a TSP50 promoter-driven luciferase reporter system, we identified etoposide-an FDA-approved topoisomerase II (TOP2) inhibitor-as a potent suppressor of TSP50 transcription. Etoposide can effectively reduces the activity of TSP50 promoter, thereby inhibiting its mRNA and protein expression. Functionally, etoposide markedly inhibits SKCM cells proliferation and triggers ferroptosis, with these effects mediated by TSP50 downregulation. In xenograft models, etoposide treatment significantly attenuated tumor growth with favorable safety profiles. Mechanistically, etoposide stabilizes p53 by weakening the MDM2-p53 interaction while enhancing MDM2-TOP2α binding. CUT&Tag and RT-qPCR revealed that p53 binds to a specific region (-200 to -249 bp) of TSP50 promotor, leading to transcriptional repression. Our findings delineate a novel TOP2α/MDM2/p53/TSP50 axis in SKCM and propose etoposide as a precision therapy for TSP50-overexpressing melanomas.

Gastric cancer (GC) remains one of the leading causes of cancer-related mortality worldwide. Ubiquitin-conjugating enzyme E2 K (UBE2K), defined as an E2, is involved in various cellular processes. N6-methyladenosine (m6A) is one of the most abundant subtypes of RNA modifications. However, the systematic role of UBE2K and whether UBE2K undergoes an m6A modification in GC remain unknown. The expression and prognosis of UBE2K in GC were analyzed through an online database. RT-qPCR, western blot and IHC were used to test the expression of UBE2K in GC tissues and cells. CCK-8, colony formation, transwell, wound healing and sphere formation assays were conducted to explore UBE2K's function in vitro. The subcutaneous mouse model was generated to validate UBE2K's role in tumorigenesis. RNA immunoprecipitation and RNA stability experiment were applied to investigate the molecular mechanism of UBE2K. Higher expression of UBE2K was found in GC tissues and predicted worse prognosis. UBE2K knockdown suppressed the malignant progression of GC cells both in vitro and in vivo. Mechanistically, we found that UBE2K was regulated by m6A modification. WTAP was further revealed as the m6A writer of UBE2K to enhance UBE2K RNA stability. Finally, functional rescue experiments showed that silencing WTAP reversed the oncogenic effects of UBE2K overexpression on GC cells, whereas WTAP attenuated the suppression of GC cells induced by UBE2K knockdown. Our findings indicate WTAP-mediated m6A modification upregulates UBE2K and the WTAP/UBE2K axis facilitates GC progression, suggesting a potential therapeutic target for GC treatment.

Psoriasis is a chronic inflammatory skin disorder characterized by dysregulated lipid metabolism, yet the key molecular drivers remain unclear. This study aimed to identify and validate novel metabolic regulators in psoriasis. Using a multi-stage bioinformatics analysis of public datasets with three machine learning algorithms, Choline Kinase Beta (CHKB) was identified as a key upregulated gene strongly associated with sphingolipid metabolism. This finding was validated in clinical samples, where CHKB expression was significantly elevated in psoriatic lesions compared to healthy controls. To investigate its functional role, CHKB was knocked down in an imiquimod-induced psoriasis mouse model and a cytokine-stimulated keratinocyte model. In vivo, CHKB knockdown ameliorated disease severity, reducing epidermal hyperproliferation, inflammation, and oxidative stress. In vitro, silencing CHKB inhibited keratinocyte hyperproliferation, induced G1 cell cycle arrest, and suppressed the secretion of pro-inflammatory cytokines. Mechanistically, CHKB knockdown altered sphingolipid metabolism, increasing ceramide levels, and concurrently inhibited the activation of the pro-survival PI3K/Akt/GSK3β signaling pathway in both models. Furthermore, a rescue experiment confirmed that the pro-psoriatic effects of CHKB overexpression in keratinocytes were dependent on this metabolic pathway, as they were reversed by the sphingolipid synthesis activator 4-HPR. Collectively, these findings establish that CHKB promotes psoriasis pathogenesis by regulating sphingolipid metabolism and activating PI3K/Akt/GSK3β signaling, highlighting it as a novel therapeutic target.

Immune checkpoint blockade (ICB) provides limited benefit in triple-negative breast cancer (TNBC), partly due to a lactate-rich, immunosuppressive tumor microenvironment (TME). Integrative bulk and single-cell transcriptomics, corroborated by tissue analyses, identify MCT4 as the predominant lactate transporter in TNBC, while supporting a context-dependent contribution of MCT1, and reveal an inverse association between MCT4 and intratumoral CD8+ T cells. We therefore tested whether inhibition of monocarboxylate transporters could recondition the TME. The repurposed agent syrosingopine, a dual MCT1/MCT4 inhibitor, consistently blocked lactate export across MCT1+ and MCT4+ models without altering transporter/LDH abundance, and reduced tumor cell PD-L1 while restoring T-cell effector function. Syrosingopine also sensitized tumor cells to NK-cell cytotoxicity without detectable toxicity in immune cells. In immunocompetent TNBC models, syrosingopine synergized with anti-PD-1 to suppress tumor growth, remodel the immune landscape, and prolong survival, while genetic perturbation of MCTs recapitulated key metabolic and immunologic phenotypes. These findings identify tumor lactate export as an important metabolic barrier to antitumor immunity in TNBC and support MCT-targeted lactate transport inhibition as a promising strategy to reprogram the TME and improve immunotherapeutic efficacy.

Diabetic kidney disease (DKD) remains a leading cause of global renal failure, with tubular injury driven by mitochondrial dysfunction representing a critical yet therapeutically unaddressed mechanism. Although the flavonolignan silibinin has demonstrated renoprotective potential, its precise molecular targets and mechanisms in DKD have remained unclear. In this study, we combined integrated computational docking, biophysical assays, and comprehensive in vivo and in vitro models to investigate silibinin's interaction with the growth hormone secretagogue receptor-1α (GHSR-1α). We demonstrated that silibinin directly binds to and activates GHSR-1α, triggering a signaling cascade characterized by liver kinase B1 (LKB1) phosphorylation, nuclear export, and complex formation with mouse protein 25 (MO25). This interaction leads to sustained AMP-activated protein kinase (AMPK) activation, which in turn restores mitophagy and alleviates oxidative stress, inflammation, and apoptosis in renal tubular cells. Crucially, these protective effects were abolished by the genetic or pharmacological inhibition of GHSR-1α. Collectively, these findings establish that silibinin mitigates DKD-associated tubular injury by activating the GHSR-1α/LKB1/AMPK axis to promote mitochondrial quality control.

This study aimed to determine whether hepatocytes acquire stemness properties during their dedifferentiation toward myofibroblast-like phenotype and to evaluate the role of TGF-β1 signaling in mediating this process during liver fibrosis (LF) progression. LF was induced in male Sprague-Dawley (SD) rats, and tissues were analyzed at 4, 8, and 12 weeks using histological staining, immunohistochemistry, immunofluorescence, and biochemical approaches. In parallel, in-vitro experiments were performed in HepG2 cells to further investigate fibrosis-related signaling mechanisms. TA administration resulted in progressive hepatocellular injury, characterized by macrophage infiltration/inflammation and extensive collagen deposition in the periportal and central vein areas. Persistent oxidative stress was evidenced by increased NOX2 and malondialdehyde (MDA) levels, together with reduced antioxidant defenses. These alterations were associated with sustained activation of the Smad2/Smad3 pathway downstream of TGF-β1. Concurrently, hepatocytes showed induction of stemness-associated transcription factors, including Oct4, Runx2, and Sox9, along with partial loss of hepatocyte identity markers such as albumin and HNF4α, suggesting the acquisition of partial myofibroblast-like characteristics, including α-SMA and Col I and Col III expression. Dysregulated extracellular matrix turnover was further indicated by increased TIMP1 and reduced MMP9 expression. In-vitro inhibition of TGF-β1 signaling and suppression of Oct4 significantly attenuated TA-induced fibrotic responses in HepG2 cells, supporting the role of TGF-β1-Oct4 signaling in hepatocyte partial differentiation and LF remodeling. This dual mechanism underscores the role of hepatocyte differentiation in LF progression and broadens the therapeutic landscape.

Resistance to molecular-targeted agents, represented by sorafenib (SOR), poses a major challenge in the treatment of hepatocellular carcinoma (HCC). Huaier (HUA), a traditional Chinese medicine used as an adjuvant cancer therapy, has demonstrated favorable efficacy in clinical practice for advanced HCC. This study demonstrates that HUA reverses SOR resistance in HCC and exhibits synergistic effects with SOR by modulating NCOA4-mediated ferritinophagy, thereby influencing iron and lipid metabolic pathways associated with ferroptotic vulnerability. In SOR-resistant Huh7R cells and mouse xenograft models, HUA alone or combined with SOR disrupted iron homeostasis through ferritinophagy induction, promoted Fe3+ reduction to Fe2+, enhanced ROS generation, induced lipid peroxidation, and concurrently reduced lipid droplet storage and triglyceride accumulation. Mechanistically, HUA upregulated NCOA4 and increased the LC3B-II/I ratio, leading to FTH1 degradation. Accumulated Fe2+ drove robust ROS production via the Fenton reaction, exacerbated lipid peroxidation, upregulated ACSL4, and downregulated SCD1 and GPX4, collectively inducing ferroptosis, a form of regulated cell death specifically rescued by ferrostatin-1 or deferoxamine but not by Z-VAD-FMK or necrostatin-1, with minimal caspase activation. Furthermore, this cascade markedly downregulated PLIN2, resulting in energy depletion in Huh7R cells and tumor tissues, thereby impairing adaptive survival and ultimately reversing SOR resistance. Notably, NCOA4 silencing substantially attenuated HUA's efficacy in overcoming SOR resistance. These findings highlight the role of HUA in promoting NCOA4-dependent ferritinophagy and modulating iron and lipid metabolism to enhance ferroptotic sensitivity, providing a rationale for the clinical development of HUA + SOR combination therapy in HCC.

In neurodegenerative diseases, microglia commonly accumulate toxic levels of cholesterol, compromising their ability to resolve the neuroinflammatory response. Here, we explored the role of neurosteroidogenesis, a complex cholesterol-metabolizing pathway that produces anti-inflammatory neurosteroids, in regulating cholesterol dynamics in IL-1β-activated human microglia. Our investigation focused on the Translocator protein (TSPO, 18 kDa), which plays a pivotal role in initiating neurosteroidogenesis, representing its rate-limiting step. Microglia in which TSPO was knocked down (TSPO KD) exhibited a marked reduction in neurosteroid biosynthesis suggesting an impaired cholesterol metabolism. Concurrently, these cells showed upregulated expression of the SREBP/HMGCR/Fdft-1/CEH axis, indicating compensatory activation of the systems aimed at increasing cholesterol availability, and downregulated cholesterol membrane efflux. As a result of these dynamics, excessive cholesterol significantly accumulated, suggesting inadequate cholesterol clearance. This dysregulation was further exacerbated in IL-1β-treated TSPO KD microglia. The impairment of neurosteroidogenic biosynthetic capacity, combined with pronounced downregulation of SREBP/HMGCR/Fdft-1/CEH axis and cholesterol membrane efflux, resulted in a severe cholesterol overload, highlighting a complete disruption of cholesterol trafficking mechanism cross-talks. Noteworthy, these cells exhibited hallmarks of neurodegenerative diseases-associated microglia (MGnD), including heightened inflammatory reactivity. On the other hand, the stimulation of TSPO-mediated neurosteroidogenesis, known to promote a reparative microglial phenotype, significantly reduced cholesterol accumulation. Neurosteroids such as allopregnanolone and estradiol emerged as key mediators in enhancing cholesterol clearance. In conclusion, these findings underscore that native neurosteroidogenesis is a crucial autocrine regulator of cholesterol trafficking in activated human microglia. They further highlight the therapeutic potential of targeting TSPO-mediated neurosteroidogenesis for the treatment of neuroinflammatory-based diseases by restoring cholesterol homeostasis and promoting reparative functions in MGnD.

Atrial fibrillation (AF), the most prevalent form of cardiac arrhythmia, frequently develops as a complication of acute myocardial infarction (MI). Nonetheless, the temporal dynamics of gene expression and key signaling pathways implicated in the development of AF following MI remain elusive. Male wild-type C57BL/6 mice were subjected to coronary artery ligation to induce MI for 1, 3, or 7 days. AF inducibility, atrial diameter, and pathological alterations were examined using programmed intracardiac stimulation, echocardiography, and histological staining. Temporal gene expression profiles were analyzed via microarray analysis. A total of 3364 differentially expressed genes (DEGs) were identified in atrial tissues at 1, 3, and 7 days post-MI compared to sham controls. These DEGs were primarily associated with mitochondrial function and the citrate cycle (TCA cycle) in atrial tissues following MI. Furthermore, co-expression network analysis revealed that APAF1-interacting protein (APIP) was centrally positioned in the gene co-expression network. Moreover, its expression was significantly downregulated in atrial tissues across various time points following MI. Cardiomyocyte-specific overexpression of APIP significantly attenuated atrial remodeling and fibrillation following MI. These beneficial effects were accompanied by elevated Mfn1/Mfn2 and p-Drp1(S637) levels, reduced Drp1 expression levels, and enhanced mitochondrial function. Finally, APIP upregulated citrate synthase (CS), enhanced respiratory complexes I-V, and significantly increased ATP synthesis. This study systematically characterized temporal changes in differentially expressed genes (DEGs) associated with AF following MI and highlights the protective role of APIP in mitigating AF development post-MI, positioning it as a therapeutic target for AF management.