Cell Death Discovery最新文献

Derangements in protein homeostasis and associated proteotoxicity mark acute, chronic, and drug-induced hepatocellular injury. Metabolic dysfunction-associated proteasomal inhibition and the use of proteasome inhibitors often underlie such pathological hepatic proteotoxicity. In this study, we sought to identify a candidate deubiquitinating enzyme (DUB) responsible for reversing the proteotoxic damage. To this end, we performed a siRNA screening wherein 96 DUBs were individually knocked down in HepG2 cells under proteasomal inhibitor-induced stress for dual readouts, apoptosis, and cell viability. Among the putative hits, we chose JOSD1, a member of the Machado-Josephin family of DUBs that reciprocally increased cell viability and decreased cell death under proteotoxicity. JOSD1-mediated mitigation of proteotoxicity was further validated in primary mouse hepatocytes by gain and loss of function studies. Marked plasma membrane accumulation of monoubiquitinated JOSD1 in proteotoxic conditions is a prerequisite for its protective role, while the enzymatically inactive JOSD1 C36A mutant was conversely polyubiquitinated, does not have membrane localisation and fails to reverse proteotoxicity. Mechanistically, JOSD1 physically interacts with the suppressor of cytokine signalling 1 (SOCS1), deubiquitinates it and enhances its stability under proteotoxic stress. Indeed, SOCS1 expression is necessary and sufficient for the hepatoprotective function of JOSD1 under proteasomal inhibition. In vivo, adenovirus-mediated ectopic expression or depletion of JOSD1 in mice liver respectively protects or aggravates hepatic injury when challenged with proteasome blocker Bortezomib. Our study thus unveils JOSD1 as a potential candidate for ameliorating hepatocellular damage in liver diseases.

Radiotherapy (RT) is a crucial treatment for colorectal cancer (CRC) patients, but it often fails to induce systemic antitumor immunity. CD73, an immunomodulatory factor, is upregulated after RT and associated with poor prognosis in CRC patients. This study aims to elucidate the mechanisms driving RT-induced CD73 upregulation in CRC and investigate how combining RT with CD73 blockade stimulates immune responses and induces abscopal effects. Findings revealed that RT-induced CD73 upregulation is mediated by the ataxia telangiectasia and Rad3-related (ATR) pathway and correlated with RT tolerance, as demonstrated through flow cytometry, immunofluorescence, and Western Blotting. Using flow cytometry and multicolor immunofluorescence, experiments demonstrated that in CRC subcutaneous tumor models, combination therapy reduces the infiltration of myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and regulatory T cells (Tregs) while increasing dendritic cells (DCs) and CD8 + T cells, resulting in superior antitumor responses. Additionally, results from flow cytometry, Western Blot, and RNA sequencing demonstrated that combination therapy enhances the antigen-presenting ability of DCs and activates tumor antigen-specific CD8 + T cells, improving their function and delaying their depletion. The activation of the cGAS-STING and IFN-I pathways is crucial for this effect. In summary, the integration of RT with CD73 blockade effectively reverses the immunosuppressive TME and invigorates CD8 + T cell-driven, specific antitumor immune responses. These insights shed fresh light on the mechanisms governing the synergistic modulation of immunity by RT and CD73 blockade in CRC, offering promising avenues for the advancement of therapeutic strategies against CRC.

Staphylococcus aureus is an important human commensal which persistently colonizes up to 30% of the human population, predominantly within the nasal cavity. The commensal lifestyle of S. aureus is complex, and the mechanisms underpinning colonization are not fully understood. S. aureus can induce an immunosuppressive environment in the nasal tissue (NT) by driving IL-10 and IL-27 to facilitate nasal colonization, indicating that S. aureus has the capacity to modulate the local immune environment for its commensal habitation. Mounting evidence suggests commensal bacteria drive type 1 interferons (IFN-I) to establish an immunosuppressive environment and whilst S. aureus can induce IFN-I during infection, its role in colonization has not yet been examined. Here, we show that S. aureus preferentially induces IFN signaling in macrophages. This IFN-I in turn upregulates expression of proapoptotic genes within macrophages culminating in caspase-3 cleavage. Importantly, S. aureus was found to drive phagocytic cell apoptosis in the nasal tissue during nasal colonization in an IFN-I dependent manner with colonization significantly reduced under caspase-3 inhibition. Overall, loss of IFN-I signaling significantly diminished S. aureus nasal colonization implicating a pivotal role for IFN-I in controlling S. aureus persistence during colonization through its ability to induce phagocyte apoptosis. Together, this study reveals a novel strategy utilized by S. aureus to circumvent host immunity in the nasal mucosa to facilitate nasal colonization.

Emerging evidence has shown that ferroptosis and antitumor immunity response of T lymphocytes play critical roles in multiple malignancies, including gastric cancer (GC). Here, the present research aims to reveal the function of novel N⁶-methyladenosine (m⁶A) methyltransferase METTL5 on GC immune microenvironment. Clinically, elevated METTL5 was negatively correlated to the prognosis of GC patients. METTL5 high-expression repressed the Fe²⁺ accumulation and ferroptosis to promote the GC immune evasion escaping from activated PBMCs’ killing effect. Mechanistically, upregulation of METTL5 promoted NRF2 mRNA stability, thereby inactivating the ferroptosis and repressing PBMCs’ cells antitumor immunity. One valuable finding is that ferroptosis inhibitor (Ferrostatin-1, Fer-1) could reduce the antitumor immunity of cocultured PBMCs. In other words, the increase of ferroptosis might contribute to the anti-tumor efficacy of immunotherapy. Further study revealed that m⁶A reader IGF2BP1 mediated the stability of NRF2 mRNA via METTL5/m⁶A/NRF2 axis. Collectively, these results demonstrate that METTL5 functions as an oncogene in GC immune microenvironment, and highlights a critical role in T lymphocytes’ antitumor immunity.

Hepatic ischemia-reperfusion injury (HIRI) is a significant issue during liver transplantation and surgery, contributing to the liver failure or even mortality. Although extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have shown substantial potentials in cell replacement therapy of various organ ischemia reperfusion injuries (IRIs), the precise mechanisms remain unclear. In this study, we demonstrate that systemic MSC-EVs administration is predominantly absorbed by macrophages, and verified that it could significantly reduce the liver injury and inflammatory response in mice suffering from HIRI. Furthermore, treatment with MSC-EVs induces macrophage polarization toward an anti-inflammatory phenotype. Mechanistically, proteomic profiling reveals an enrichment of growth arrest-specific 6 (GAS6) in MSC-EVs, significantly promoting the activation of myeloid-epithelial-reproductive tyrosine kinase/extracellular regulated protein kinases/cyclooxygenase 2 (MerTK/ERK/COX2) signaling pathway in macrophages and further enhancing their efferocytosis efficiency. Knockdown of GAS6 via lentiviral transfection or inhibition of MerTK using UNC2025 (a MerTK small molecule inhibitor) partially eliminates the protective effects of MSC-EVs on macrophage efferocytosis and liver injury. Overall, our findings support that MSC-EVs enriched GAS6 execute an anti-inflammation effect, highlighting that treatment based on the modulation of macrophage function by MSC-EVs as a promising approach in IRI.

Cutaneous T-cell lymphoma (CTCL) is a group of primary and secondary cutaneous malignancies characterized by aberrant T-cells in the skin. Diagnosing CTCL in its early stage can be difficult because of CTCL’s ability to mimic benign cutaneous inflammatory skin diseases. CTCL has multiple subtypes with different disease progression and diagnostic parameters despite similar clinical manifestations. The accurate diagnosis and prognosis of a varied range of diseases require the detection of molecular entities to capture the complete footprint of disease physiology. Non-coding RNAs (ncRNAs) have recently been discovered as major regulators of CTCL gene expression. They can affect tumor cell growth, migration, programmed cell death (PCD), and immunoregulation through interactions with the tumor microenvironment (TME), which in turn affect CTCL progression. This review summarizes recent advances in how ncRNAs regulate CTCL cell activity, especially their role in PCD. It also discusses the potential use of ncRNAs as diagnostic and prognostic biomarkers for different subtypes of CTCL. Furthermore, prospective targets and therapeutic approaches influenced by ncRNAs are presented. A better appreciation of the intricate epigenetic landscape of CTCL is expected to facilitate the creation of innovative targeted therapies for the condition.

Nonalcoholic fatty liver disease (NAFLD) is a group of chronic liver disease which ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) and is characterized by lipid accumulation, inflammation activation, fibrosis, and cell death. To date, a number of preclinical studies or clinical trials associated with therapies targeting fatty acid metabolism, inflammatory factors and liver fibrosis are performed to develop effective drugs for NAFLD/NASH. However, few therapies are cell death signaling-targeted even though the various cell death modes are present throughout the progression of NAFLD/NASH. Here we summarize the four types of cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis in the NAFLD and the underlying molecular mechanisms by which the pathogenic factors such as free fatty acid and LPS induce cell death in the pathogenesis of NAFLD. In addition, we also review the effects of cell death-targeted therapies on NAFLD. In summary, our review provides comprehensive insight into the roles of various cell death modes in the progression of NAFLD, which we hope will open new avenues for therapeutic intervention.

Dry eye, recognized as the most prevalent ocular surface disorder, has risen to prominence as a significant public health issue, adversely impacting the quality of life for individuals across the globe. Despite decades of extensive research into the chronic inflammation that characterizes dry eye, the intricate mechanisms fueling this persistent inflammatory state remain incompletely understood. Among the various cellular components under investigation, mitochondria-essential for cellular energy production and homeostasis-have attracted increasing attention for their role in dry eye pathogenesis. This involvement points to mechanisms such as oxidative stress, apoptosis, and sustained inflammation, which are central to the progression of the disease. This review aims to provide a thorough exploration of mitochondrial dysfunction in dry eye, shedding light on the critical roles played by mitochondrial oxidative stress, apoptosis, and mitochondrial DNA damage. It delves into the mechanisms through which diverse pathogenic factors may trigger mitochondrial dysfunction, thereby contributing to the onset and exacerbation of dry eye. Furthermore, it lays the groundwork for an overview of current therapeutic strategies that specifically target mitochondrial dysfunction, underscoring their potential in managing this complex condition. By spotlighting this burgeoning area of research, our review seeks to catalyze the development of innovative drug discovery and therapeutic approaches. The ultimate goal is to unlock promising avenues for the future management of dry eye, potentially revolutionizing treatment paradigms and improving patient outcomes. Through this comprehensive examination, we endeavor to enrich the scientific community's understanding of dry eye and inspire novel interventions that address the underlying mitochondrial dysfunctions contributing to this widespread disorder.

Down syndrome (DS), caused by an additional chromosome 21, has a high risk of congenital heart defects (CHD), one of the primary causes of mortality in DS newborns. To elucidate the pathogenetic mechanisms underlying this condition, we explored the role of RNA m6A methylation, regulated by METTL3, in DS cardiac development and its impact on the expression of SH3BGR, a gene located at Down syndrome congenital heart disease (DS-CHD) minimal region. We analyzed DS fetal cardiac tissues to assess RNA m6A methylation levels and identify potential contributors. RNA sequencing was performed to detect differentially expressed genes in the same tissues. To further understand METTL3's function in heart development, we inactivated Mettl3 in the developing mouse heart to mimic the significantly reduced METTL3 observed in DS cardiac development. Additionally, human cardiomyocyte AC16 cells were used to investigate the molecular mechanism by which METTL3 regulates SH3BGR expression. Apoptosis was analyzed to evaluate METTL3's effect on heart development through SH3BGR regulation. Reduced m6A modification and decreased METTL3 expression were observed in human DS fetal hearts, along with a significant increase of SH3BGR expression. METTL3, through m6A modification, was found to regulate SH3BGR expression, by influencing mRNA stability. METTL3-deficient mouse embryos exhibited heart malformation with increased apoptosis, emphasizing its role in heart development. In DS hearts, METTL3 downregulation and SH3BGR upregulation, potentially orchestrated by abnormal m6A modification, contribute to gene dysregulation and apoptosis. This study reveals novel insights into DS cardiac pathology, highlighting the intricate role of METTL3 in DS congenital heart defects and presenting the m6A modification of SH3BGR as a potential therapeutic target.