ISSN: 1449-2288International Journal of Biological Sciences
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Int J Biol Sci 2024; 20(4):1529-1546. doi:10.7150/ijbs.92267 This issue Cite
Research Paper
Malat1 regulates PMN-MDSC expansion and immunosuppression through p-STAT3 ubiquitination in sepsis
1. Department of Critical Care Medicine, Children's Hospital of Fudan University, Shanghai, China.
2. Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China.
3. Institute of Pediatrics, Children's Hospital of Fudan University, National Children's Medical Center, and the Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
4. National Health Commission (NHC) Key Laboratory of Neonatal Diseases, Fudan University, Shanghai, China.
5. Fujian Key Laboratory of Neonatal Diseases, Fujian, China.
6. Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK.
#These authors contributed equally to this work.
Abstract
Myeloid-derived suppressor cells (MDSCs) expand during sepsis and contribute to the development of persistent inflammation-immunosuppression-catabolism syndrome. However, the underlying mechanism remains unclear. Exploring the mechanisms of MDSCs generation may provide therapeutic targets for improving immune status in sepsis. Here, a sepsis mouse model is established by cecal ligation and perforation. Bone marrow cells at different sepsis time points are harvested to detect the proportion of MDSCs and search for differentially expressed genes by RNA-sequence. In lethal models of sepsis, polymorphonuclear-MDSCs (PMN-MDSCs) decrease in early but increase and become activated in late sepsis, which is contrary to the expression of metastasis-associated lung adenocarcinoma transcript 1 (Malat1). In vivo, Malat1 inhibitor significantly increases the mortality in mice with late sepsis. And in vitro, Malat1 down-regulation increases the proportion of PMN-MDSCs and enhanced its immunosuppressive ability. Mechanistically, Malat1 limits the differentiation of PMN-MDSCs by accelerating the degradation of phosphorylated STAT3. Furthermore, Stattic, an inhibitor of STAT3 phosphorylation, improves the survival of septic mice by inhibiting PMN-MDSCs. Overall, the study identifies a novel insight into the mechanism of sepsis-induced MDSCs and provides more evidence for targeting MDSCs in the treatment of sepsis.
Keywords: Experimental sepsis, Polymorphonuclear myeloid-derived suppressor cell, Malat1, STAT3 pathway, Ubiquitination
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