Cell Death Discovery最新文献

Uveal melanoma (UM) is the most common intraocular tumor, and despite being rare, it accounts for nearly 13% of melanoma-related deaths. Indeed, patients with metastatic disease have typically survival rates of less than one year, with little improvement over the past few decades. Although TP53 mutations are uncommon in UM, recent findings highlight a dysfunctional p53 pathway in this cancer. Given its crucial role in mediating DNA damage responses, we analyzed the p53 protein functionality and downstream target activation in a panel of UM cell lines in response to standard-of-care treatments (i.e., cisplatin and proton-beam irradiation). Although most of the analyzed cells retained a wild-type p53, we observed a wide range of p53 protein stabilization and targets' activation. Recently, p53 isoforms have been recognized as modifiers of p53 activity, and their biology and functions depend on cellular context. We observed that UM cells express a broad spectrum of p53 isoforms, including Δ160p53α and Δ133p53β and the longer variants Δ40p53β and p53β. Interestingly, the down-regulation of the short p53 isoforms (Δ133/Δ160) revealed their contribution to promoting cell growth and in mitigating cell death triggered by standard-of-care therapies. Moreover, we verified the wild-type p53 status in a panel of 32 UM cases and analyzed the expression levels of p53 isoforms. Our results indicated a correlation between higher expression levels of Δ40p53α or Δ133p53γ isoforms and the development of more aggressive cancers. Our findings suggest that shorter p53 isoforms can promote cancer aggressiveness and therapy resistance, thereby providing crucial insights into UM pathogenesis.

Aminoacyl tRNA synthetases (AaRSs) are enzymes that play a role in maintaining translational fidelity by ensuring the accurate loading of amino acids to their cognate tRNAs. Mutations in the AaRSs are linked to diverse human diseases, including neurological disorders and various types of cancer. Among AaRSs, mutations in wars-1, a tryptophanyl tRNA synthetase, have been associated with cancer. Despite the extensive knowledge of WARS-1, there is no comprehensive understanding of its contribution to pathogenesis. In our previous study, we discovered the impact of WARS-1 on genomic integrity. We showed that WARS-1 depletion leads to a significant accumulation of free tryptophan (Trp), resulting in pronounced genomic instability, including the formation of chromatin bridges and micronuclei, and cell cycle arrest. In this study, we demonstrate that wars-1 knockdown induces apoptosis in the germline of C. elegans.

Bronchopulmonary dysplasia (BPD), a frequent complication in preterm infants receiving supplemental oxygen, is characterized by hyper-activation of macrophage inflammasomes, exuberant release of pro-inflammatory cytokines such as interleukin-1β (IL-1β), and Gasdermin D (GSDMD)-driven pyroptosis. However, the precise contribution of macrophage pyroptosis to BPD pathogenesis remains incompletely defined, and effective pharmacological interventions are still lacking. Using neonatal C57BL/6 wild-type (WT) and GSDMD-knockout (GSDMD^-/-) mice, we established a hyperoxia-induced BPD model (85% FiO₂, 14 days) and administered the GSDMD inhibitor disulfiram (50 mg kg⁻¹ intraperitoneally, once daily for 7 days). In vivo, we assessed lung histopathology, IL-1β levels, alveolarization, and vascular development; ex vivo, we isolated bone-marrow-derived macrophages (BMDMs) to quantify pyroptotic markers, M1/M2 polarization, and antibacterial capacity. GSDMD deletion or disulfiram treatment significantly attenuated macrophage and neutrophil infiltration, decreased pulmonary IL-1β concentrations, improved alveolar architecture and vascular density, and reduced overall cell death. BMDMs from GSDMD^-/- mice displayed diminished M1 polarization, enhanced bacterial killing, yet unaltered zymosan phagocytosis. Collectively, these findings identify GSDMD-mediated macrophage pyroptosis as a critical driver of BPD-related lung injury. Targeted GSDMD inhibition, whether genetic or pharmacologic, alleviates experimental BPD by down-regulating IL-1β and promoting alveolar development, thereby providing a promising therapeutic avenue for this devastating neonatal disorder.

Fibroblast-like synoviocytes (FLSs) contribute to the advancement of rheumatoid arthritis (RA) through enhanced metabolic reprogramming. This research focused on exploring the role and underlying mechanism of ubiquitin-specific protease 5 (USP5) in modulating the glycolysis and activation of RA-FLSs. Here, we identified that knockdown of USP5 in RA rats reduced synovial inflammation and glycolytic activity, as evidenced by decreased serum lactate levels and GLUT1 expression. In RA-FLSs, USP5 knockdown or treatment with 2-DG reduced cell proliferation, migration, invasion, cytokine production, and glycolysis, while increased apoptosis. Mechanistically, USP5 stabilized METTL14 by inhibiting its ubiquitination, while METTL14 enhanced the m⁶A modification of GLUT1 mRNA, thereby increasing its expression. Furthermore, overexpression of METTL14 partially reversed the effects of USP5 knockdown on glycolysis and inflammatory activation in RA-FLSs. Additionally, knockdown of METTL14 inhibited RA-FLS glycolysis and inflammatory activation by downregulating GLUT1. Collectively, USP5 stabilized METTL14-mediated m⁶A modification of GLUT1 by inhibiting the ubiquitination of METTL14, thereby enhancing glycolysis and inflammatory activation in RA-FLSs. These results suggest that the USP5/METTL14/GLUT1 axis could be a potential therapeutic target for RA.

Maf1 is a well-known RNA polymerase III repressor and functions as a tumor suppressor due to its role in inhibiting tRNA synthesis. However, the role of Maf1 in hepatocellular carcinoma (HCC) remains unclear. This study identified Aurora-A as a novel upstream regulator of Maf1 in HCC. We demonstrated that Aurora-A interacts with the C domain of Maf1 and phosphorylates it at Threonine-212, leading to increased protein stability and cytosolic accumulation of Maf1. Importantly, the Aurora-A-enhanced cytosolic localization of Maf1 promotes mitochondrial dysfunction and glycolytic activity, ultimately driving HCC cell proliferation. In contrast, mutation of the Thr-212 site abolishes these effects, confirming its critical role. Significantly, elevated Maf-1 expression correlates with unfavorable clinical outcomes in HCC, particularly among patients with high Aurora-A expression. Furthermore, HCC cells with overexpressed Maf1 have heightened sensitivity to Aurora-A inhibitors, suggesting a potential therapeutic vulnerability. Our study uncovers a non-canonical, oncogenic role of Maf1 in HCC and highlights the Aurora-A-Maf1 axis as a promising target for personalized cancer therapy.

Chemoresistance remains a major challenge in cervical cancer (CVC) treatment. Lysosomal function, mediated by V-ATPase, is critical in cancer progression and drug resistance. CLC3, a chloride channel that regulates lysosomal acidification, may contribute to chemoresistance by modulating V-ATPase activity. This study aims to investigate the role of CLC3 in modulating lysosomal function, chemoresistance, and tumorigenesis in CVC. CLC3 expression in CVC cell lines was assessed, and chemoresistance was evaluated using IC50 calculations for cisplatin, paclitaxel, and 5-FU. Effects of CLC3 downregulation or overexpression on lysosomal pH, autophagy, apoptosis, cell proliferation, cell cycle progression, and tumor stemness were analyzed. A general V-ATPase inhibitor was used to assess changes in lysosomal pH and protein degradation, while a2v-mAb was applied to investigate the interaction between CLC3 and specific V-ATPase subunits. In vivo, a mouse xenograft model was used to assess the effects of CLC3 modulation on tumor growth and response to chemoresistance. CLC3 was upregulated in CVC cells, reducing chemosensitivity. Overexpression of CLC3 enhanced cytosolic alkalinization, lysosomal acidification, and protein degradation while inhibiting autophagy and apoptosis independently. CLC3 promoted cell proliferation and tumor stemness via V-ATPase activity, particularly ATP6V1A. CLC3 knockdown combined with V-ATPase inhibition decreased proliferation and increased cisplatin sensitivity. In vivo, CLC3 knockdown with cisplatin reduced tumor volume and increased apoptosis, whereas overexpression promoted cisplatin resistance. CLC3 plays a pivotal role in chemoresistance and tumor progression in CVC by regulating lysosomal function via V-ATPase. Targeting CLC3 and its downstream pathways may provide novel therapeutic strategies to overcome chemoresistance.

Fuchs endothelial corneal dystrophy (FECD) is the leading indication of corneal transplantation worldwide and the focus of pathogenesis has been on the corneal endothelium. Instead of cellular analysis, we aimed to identify the protein changes of aqueous humor (AH) in patients with FECD and investigate in more detail the relationship between AH and corneal endothelium. We collected 13 AH samples of 7 early/middle stage FECD patients and 6 control patients during routine cataract surgery. The proteomes of AH were profiled with the 4D label-free quantitative tandem mass spectrometry. Among 1613 identified proteins, 44 proteins exhibited above two-fold upregulation in the AH of FECD patients than control patients. Gene ontology (GO) analysis showed the enrichment of mitochondrial components, which were further validated by ELISA of mitochondrial proteins SLC25A3, PC, and PARK7. Moreover, immunofluorescence staining and ultrastructural observation were conducted in clinical specimens, mouse corneal endothelium and cultured human corneal endothelial cells (HCECs). The mitochondrial protein TOM20 was reduced in the FECD corneal endothelium, accompanied by damaged mitochondrial ejection. We next isolated extracellular vesicles by ultracentrifugation from HCECs and revealed that the mitochondria copy numbers were significantly increased in UVA-irradiated cells. Inhibition of exosome biogenesis aggravated cell death and mitochondrial membrane potential impairment in FECD endothelial cells. Taken together, our results provided novel insights into the proteome characterization of the AH from FECD patients and offered new perspective to deepen the impaired mitochondrial quality control in the pathogenesis of FECD.

Damage to inner hair cells (IHCs) is a leading cause of hearing loss, typically initiating at the base region of the basilar membrane. However, the mechanisms and preventative strategies for IHC damage remain to be elucidated. This study revealed that IHCs in the low-frequency region exhibit a significantly faster calcium clearance rate than high-frequency IHCs. This difference is associated with different PMCA1 expression. We then generated an IHC-specific Pmca1 knockout mouse model (Pmca1 CKO) exhibiting profound hearing loss and IHC death. Using single-cell RNA-seq analysis, we found that the differentially expressed genes (DEGs) were related to tetrahydrofolate biosynthesis, DNA damage, and DNA repair dysfunction. We therefore treated Pmca1 CKO mice with folic acid and found that it protected IHCs by reducing γ-H2A.X levels. In addition, we found that folic acid protected IHCs from noise-induced damage. Overall, our findings suggest that disrupted calcium homeostasis plays a role in IHC damage and that folic acid may be a promising therapeutic agent for protecting hair cells.

Hepatocellular carcinoma (HCC) is an aggressive liver cancer with high recurrence and poor prognosis. This study aims to explore USP13's role in HCC progression and assess its potential as a therapeutic target to induce ferroptosis and enhance immune response. HCC patient-derived organoids (PDOs), HCC cell lines and animal models were utilized to evaluate the anti-cancer responses of USP13 inhibition. We analyzed the correlation of USP13 expression and immune cell infiltration using single-cell RNA sequencing, flow cytometry analysis. A USP13 inhibitor, 2-Methoxyestradiol (2-Met), was used to evaluate its therapeutic efficacy. USP13 was found to be highly expressed in HCC tissues and was correlated with poor prognosis. Single-cell RNA sequencing analysis indicated that high expression of USP13 in HCC cells was associated with decreased enrichment of CD8 + T cells in the tumor microenvironment (TME). Targeting USP13 reduced HCC cell proliferation, stemness, and cholesterol metabolism while promoting ferroptosis and enhancing T cell-mediated cytotoxicity. Mechanistically, USP13 stabilized ACLY via inhibiting the K48-specific poly-ubiquitination process on ACLY protein at the K726 site. Under hypoxia condition, HIF-1α upregulates the transcription of USP13 by binding to its promoter region, which stabilizes ACLY protein. Overall, this research reveals that hypoxia-induced USP13 expression drives ferroptosis resistance and tumor immune evasion in hepatocellular carcinoma through the stabilization of ACLY. Pharmacological inhibition or knockdown of USP13 impedes HCC progression, induces ferroptosis, and enhances T cell-mediated cytotoxic effects. These results highlight that USP13 could be a promising therapeutic target for HCC.

The role of deubiquitinating enzymes in the tumor immune microenvironment (TIME) remains understudied. Here, we sought to identify the mechanisms of USP25 modulation in the TIME of head and neck squamous cell carcinoma (HNSCC). Bioinformatics analysis was performed to screen differentially expressed novel deubiquitinases (DUBs) in HNSCC. The importance of USP25 in clinical practice was assessed in the TCGA dataset and tissue microarrays. Single-cell RNA-sequencing was applied to profile the TIME. The function of USP25 was determined through loss-of-function assays. Reduced expression of USP25 was associated with the malignant progression of HNSCC and further indicated poor prognosis. USP25 protein levels were positively correlated with CD8⁺ T-cell infiltration in HNSCC tissue cohorts, suggesting its role in modulating the TIME. Concordantly, this study revealed a reduction in myeloid-derived suppressor cells (MDSCs), concomitant with increased numbers of cytotoxic T cells in tumors with high USP25 expression. Mechanistically, we revealed that USP25 binds to TAB2, removes K63-linked ubiquitination chains, and subsequently activates MAPK signaling and the secretion of IL-6, which increases MDSCs migration. Increased MSDCs in turn antagonized functional CD8⁺ T cells in the TIME. Importantly, overexpression of USP25 increased anti-PD1 therapeutic efficacy in HNSCC in vivo. These results underscore the critical role and mechanism of USP25 in modulating the TIME in HNSCC, suggesting its potential as a therapeutic target in immune checkpoint blockade therapy.