Project description:Newborns exhibit a heightened vulnerability to inflammatory disorders due to their underdeveloped immune system, yet the underlying mechanisms remain poorly understood. Here we report that plasma spermidine is correlated with the maturity of human newborns and reduced risk of inflammation. Administration of spermidine led to the remission of neonatal inflammation in mice. Mechanistic studies revealed that spermidine enhanced the generation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) via downstream eIF5A hypusination (eIF5A-Hyp). Genetic deficiency or pharmacological inhibition of deoxyhypusine synthase (DHPS), a key enzyme of eIF5A-Hyp, diminished the immunosuppressive activity of PMN-MDSCs, leading to aggravated neonatal inflammation. The eIF5A-Hyp pathway was found to enhance mitochondrial function via histone acetylation-mediated epigenetic transcription of immunosuppressive signatures in PMN-MDSCs. These findings demonstrated spermidine-eIF5A-Hyp metabolic axis as a master switch to restrict neonatal inflammation.
Project description:Newborns exhibit a heightened vulnerability to inflammatory disorders due to their underdeveloped immune system, yet the underlying mechanisms remain poorly understood. Here we report that plasma spermidine is correlated with the maturity of human newborns and reduced risk of inflammation. Administration of spermidine led to the remission of neonatal inflammation in mice. Mechanistic studies revealed that spermidine enhanced the generation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) via downstream eIF5A hypusination (eIF5A-Hyp). Genetic deficiency or pharmacological inhibition of deoxyhypusine synthase (DHPS), a key enzyme of eIF5A-Hyp, diminished the immunosuppressive activity of PMN-MDSCs, leading to aggravated neonatal inflammation. The eIF5A-Hyp pathway was found to enhance mitochondrial function via histone acetylation-mediated epigenetic transcription of immunosuppressive signatures in PMN-MDSCs. These findings demonstrated spermidine-eIF5A-Hyp metabolic axis as a master switch to restrict neonatal inflammation.
Project description:We found that PMN-MDSCs level is elevated in the advanced ICCs tissues and is positively associated with the METTL1 and m7G tRNA modification levels. We further showed that impaired m7G tRNA modification impedes the PMN-MDSCs infiltration and inhibits ICC progression. Mechanistically, METTL1-mediated m7G tRNA modification selectively regulates the translation of human CXCL8 and mouse Cxcl5 transcripts, which facilitates the migration of PMN-MDSCs via binding to their cognate receptor CXCR2. Co-blockade of METTL1 and CXCR2 significantly enhances the efficacy of anti-PD-1 treatment in ICC. Taken together, our study reveals the cellular and molecular basis of crosstalk between ICC cells and MDSCs in shaping TIME and affecting ICIs efficacy, which enables reasonable design of new combined therapy targeting dysregulated mRNA translation and suppressive TIME.
Project description:Disruption of circadian rhythm during pregnancy produced adverse health outcomes in offspring. However, the role of maternal circadian rhythms in infants’ immunity and their susceptibility to inflammation remains poorly understood. Here we reported that disruption of circadian rhythms in pregnant mice profoundly aggravated the severity of neonatal inflammatory disorders, including necrotizing enterocolitis (NEC) and sepsis. The diminished production of maternal-derived docosahexaenoic acid (DHA) and the impaired immunosuppressive function of myeloid-derived suppressor cells (MDSCs) in neonates played a dominant role in this process. Mechanistically, DHA enhanced the immunosuppressive function of neonatal MDSCs viaPPARγ mediated mitochondrial oxidative phosphorylation. Transfer of MDSCs or perinatal supplementation of DHA relieved neonatal inflammation induced by maternal rhythms disruption. These observations revealed an important role of maternal circadian rhythms in the control of neonatal inflammation via metabolic reprograming of myeloid cells.
Project description:Disruption of circadian rhythm during pregnancy produced adverse health outcomes in offspring. However, the role of maternal circadian rhythms in infants’ immunity and their susceptibility to inflammation remains poorly understood. Here we reported that disruption of circadian rhythms in pregnant mice profoundly aggravated the severity of neonatal inflammatory disorders, including necrotizing enterocolitis (NEC) and sepsis. The diminished production of maternal-derived docosahexaenoic acid (DHA) and the impaired immunosuppressive function of myeloid-derived suppressor cells (MDSCs) in neonates played a dominant role in this process. Mechanistically, DHA enhanced the immunosuppressive function of neonatal MDSCs viaPPARγ mediated mitochondrial oxidative phosphorylation. Transfer of MDSCs or perinatal supplementation of DHA relieved neonatal inflammation induced by maternal rhythms disruption. These observations revealed an important role of maternal circadian rhythms in the control of neonatal inflammation via metabolic reprograming of myeloid cells.
Project description:Myeloid-derived suppressor cells (MDSCs) are key players in immune evasion, tumor progression and metastasis. MDSCs accumulate under various pathological states, and fall into two functionally and phenotypically distinct subsets: polymorphonuclear (PMN)-MDSCs and monocytic (M)-MDSCs. These subsets have been studied extensively in humans and mice, yet to date no study has identified MDSC subsets in dogs with spontaneous tumors. As dogs are an excellent model for human tumor development and progression, we set out to identify PMN-MDSCs and M-MDSCs in clinical canine oncology patients. We identified MDSCs as hypodense MHC class II-CD5-CD21-CD11b+ cells and show for the first time that they can also be subdivided into polymorphonuclear (CADO48A+CD14-) and monocytic (CADO48A-CD14+) subsets. The transcriptomic signatures of PMN-MDSCs and M-MDSCs are distinct from each other and from those of conventional polymorphonuclear (PMN) and monocytic cells, respectively. Notably, bioinformatic analyses reveal a statistically significant similarity between canine and previously published human MDSC gene expression patterns. As in humans, peripheral blood frequencies of canine PMN-MDSCs and M-MDSCs are significantly different in dogs with cancer compared to healthy control dogs (PMN-MDSCs: p < .001; M-MDSCs: p < .01). Furthermore, a comparison of our canine MDSC RNA-seq data with transcriptomic results previously published for human and murine MDSCs highlights five commonly upregulated genes in PMN-MDSCs in all species, suggesting that these genes are evolutionarily conserved and functionally important. Interestingly, one gene has previously been implicated in PMN-MDSC function (MMP8), but four genes (LTF, LCN2, CAMP, EBP41L3) are novel in the context of PMN-MDSCs. Our findings therefore demonstrate for the first time that dogs have two distinct populations of MDSCs, characterized by specific phenotypic and transcriptomic signatures that share key features of human MDSC subsets. Importantly, by leveraging the power of evolution, we have identified additional conserved genes in PMN-MDSCs of multiple species which may play a role in MDSC function. Our findings therefore validate the dog as a model for studying MDSCs in the context of cancer.
Project description:It is suggested that decidual polymorphonuclear myeloid-derived suppressor cell (PMN-MDSCs) are a group of activated suppressive neutrophils. Decidual microenvironment can facilitate circulating neutrophils with phenotypes and functions of PMN-MDSCs. The mechanism of PMN-MDSCs differentiation induced by decidual microenvironment has not been fully understood. Here we performed whole genome expression profile of 3 decidual PMN-MDSCs and autologous neutrophils from normal early pregnancy. Total RNA were extracted. The arrays were scanned by the Agilent Scanner G2505C. There were differences of gene expression pattern between decidual PMN-MDSCs and autologous neutrophils in early normal pregnancy.
Project description:To identify lncRNAs involved in regulating PMN-MDSCs, an Arraystar lncRNA microarray was performed to determine the lncRNA expression profile in PMN-MDSCs. Compared to those in CD11b+Ly6G+ cells under physiological conditions, the expression of abundant lncRNAs was significantly higher in PMN-MDSCs from the tumor microenvironment. In these lncRNAs, lncRNA AK036396, whose sequencing information has been identified in the UCSC database, was one of the most significantly upregulated lncRNAs and its expression was confirmed by quantitative real-time PCR (qRT-PCR). In addition, microarray data indicated that Fcnb expression, which can be used to identify immature granuloctyes and is closely associated with granulocyte maturation, was one of the highest potential target molecules of lncRNA AK036396 in PMN-MDSCs.
Project description:CD84 is a key marker of PMN-MDSCs in multiple mouse models and patients tumor samples. Increased CD84 expression levels were found in pathophysiological conditions associated with thrombo-inflammation