Cell Death and Differentiation最新文献

Immune response genes are highly polymorphic in humans and mice, with heterogeneity amongst loci driving strain-specific host defence responses. The inadvertent retention of polymorphic loci can introduce confounding phenotypes, leading to erroneous conclusions, and impeding scientific advancement. In this study, we employ a combination of RNAseq and variant calling analyses to identify a substantial region of 129S genome, including the highly polymorphic Nlrp1 locus, proximal to Nlrp3, in one of the most commonly used mouse models of NLRP3 deficiency (Nlrp3^tm1Flv). We show that the presence of the Nlrp1^129S locus leads to an increase in NLRP1B protein expression, and a sensitising of Nlrp3^tm1Flv macrophages to NLRP1 inflammasome activation, independent of NLRP3 deficiency. Retention of 129S genome further leads to protein sequence differences and altered gene regulation across multiple cell types, including of the key tissue-resident macrophage marker, TIM4. Using alternative models of NLRP3 deficiency, including a previously undescribed conditional Nlrp3 allele enabling precise temporal and cell-type specific control over Nlrp3 deletion, we further show that NLRP3 contributes to Talabostat-driven IL-1β release. Our study also establishes a generic framework to identify functionally relevant SNPs and assess genomic contamination in transgenic mice using RNAseq data. This allows for unambiguous attribution of phenotypes to the target gene and advances the precision and reliability of research in the field of host defence responses.

E3 ubiquitin ligases are very important for regulating antiviral immunity during viral infection. Here, we discovered that Ankyrin repeat and SOCS box-containing protein 3 (ASB3), an E3 ligase, are upregulated in the presence of RNA viruses, particularly influenza A virus (IAV). Notably, overexpression of ASB3 inhibits type I IFN (IFN-I) responses induced by Sendai virus (SeV) and IAV, and ablation of ASB3 restores SeV and H9N2 infection-mediated transcription of IFN-β and its downstream interferon-stimulated genes (ISGs). Interestingly, animals lacking ASB3 presented decreased susceptibility to H9N2 and H1N1 infections. Mechanistically, ASB3 interacts with MAVS and directly mediates K48-linked polyubiquitination and degradation of MAVS at K297, thereby inhibiting the phosphorylation of TBK1 and IRF3 and downregulating downstream antiviral signaling. These findings establish ASB3 as a critical negative regulator that controls the activation of antiviral signaling and describe a novel function of ASB3 that has not been previously reported.

Tumour immune evasion presents a significant challenge to the effectiveness of cancer immunotherapies. Recent advances in high-throughput screening techniques have uncovered that loss of antigen presentation and cytokine signalling pathways are central mechanisms by which tumours evade T cell immunity. To uncover additional vulnerabilities in tumour cells beyond the well-recognized antigen presentation pathway, we conducted a genome-wide CRISPR/Cas9 screen to identify genes that mediate resistance to chimeric-antigen receptor (CAR)-T cells, which function independently of classical antigen presentation. Our study revealed that loss of core-binding factor subunit beta (CBFβ) enhances tumour cell resistance to T cell killing, mediated through T cell-derived TNF. Mechanistically, RNA-sequencing and elemental analyses revealed that deletion of CBFβ disrupts numerous pathways including those involved in zinc homoeostasis. Moreover, we demonstrated that modulation of cellular zinc, achieved by supplementation or chelation, significantly altered tumour cell susceptibility to TNF by regulating the levels of inhibitor of apoptosis proteins. Consistent with this, treatment of tumour cells with a membrane-permeable zinc chelator had no impact on tumour cell viability alone, but significantly increased tumour cell lysis by CD8+ T cells in a TNF-dependent but perforin-independent manner. These results underscore the crucial role of intracellular zinc in regulating tumour cell susceptibility to T cell-mediated killing, revealing a novel vulnerability in tumour cells that might be exploited for the development of future cancer immunotherapeutics.

Immune cells modify their metabolic pathways in response to fungal infections. Nevertheless, the biochemical underpinnings need to be better understood. This study reports that fungal infection drives a switch from glycolysis to the serine synthesis pathway (SSP) and one-carbon metabolism by inducing the interaction of spleen tyrosine kinase (SYK) and phosphoglycerate dehydrogenase (PHGDH). As a result, PHGDH promotes SYK phosphorylation, leading to the recruitment of SYK to C-type lectin receptors (CLRs). The CLR/SYK complex initiates signaling cascades that lead to transcription factor activation and pro-inflammatory cytokine production. SYK activates SSP and one-carbon metabolism by inducing PHGDH activity. Then, one-carbon metabolism supports S-adenosylmethionine and histone H3 lysine 36 trimethylation to drive the production of pro-inflammatory cytokines and chemokines. These findings reveal the crosstalk between amino acid metabolism, epigenetic modification, and CLR signaling during fungal infection.

Defects in meiotic prophase can cause meiotic chromosome missegregation and aneuploid gamete formation. Meiotic checkpoints are activated in germ cells with meiotic defects, and cells with unfixed errors are eliminated by apoptosis. How such a surveillance process is regulated remains elusive. Here, we report that a chromosome-coupled ubiquitin-proteasome pathway (UPP) regulates meiotic checkpoint activation and promotes germ cell apoptosis in C. elegans meiosis-defective mutants. We identified an F-box protein, FBXL-2, that functions as a core component within the pathway. This chromosome-coupled UPP regulates meiotic DSB repair kinetics and chromosome dynamic behaviors in synapsis defective mutants. Disrupted UPP impairs the axial recruitment of the HORMA domain protein HIM-3, which is required for efficient germ cell apoptosis in synapsis defective mutants. Our data suggest that an efficient chromosome-coupled UPP functions as a part of the meiotic surveillance system by enhancing the integrity of the meiotic chromosome axis.

Transcription factor Foxk1 can regulate cell proliferation, differentiation, metabolism, and promote skeletal muscle regeneration and cardiogenesis. However, the roles of Foxk1 in bone formation is unknown. Here, we found that Foxk1 expression decreased in the bone tissue of aged mice and osteoporosis patients. Knockdown of Foxk1 in primary murine calvarial osteoblasts suppressed osteoblast differentiation and proliferation. Conditional knockout of Foxk1 in preosteoblasts and mature osteoblasts in mice exhibited decreased bone mass and mechanical strength due to reduced bone formation. Mechanistically, we identified Foxk1 targeted the promoter region of many genes of glycolytic enzyme by CUT&Tag analysis. Lacking of Foxk1 in primary murine calvarial osteoblasts resulted in reducing aerobic glycolysis. Inhibition of glycolysis by 2DG hindered osteoblast differentiation and proliferation induced by Foxk1 overexpression. Finally, specific overexpression of Foxk1 in preosteoblasts, driven by a preosteoblast specific osterix promoter, increased bone mass and bone mechanical strength of aged mice, which could be suppressed by inhibiting glycolysis. In summary, these findings reveal that Foxk1 plays a vital role in the osteoblast metabolism regulation and bone formation stimulation, offering a promising approach for preventing age-related bone loss.