Yang Fu1, Denian Wang2, Shuang Wang1, Qi Zhang1, Hao Liu3, Shanshan Yang4, Yanming Xu5, Binwu Ying6. 1. Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. 2. Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. 3. Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. 4. Molecular Medicine Research Center, West China School of Medicine, Sichuan University, Chengdu, 610041, Sichuan, China. 5. Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. 6. Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. yingbinwu@scu.edu.cn.
Abstract
OBJECTIVE: Programmed death 1 (PD-1) and macrophages are the most intriguing candidates in sepsis-induced inflammatory disorders. We aimed to investigate the association between monocyte PD-1 and sepsis severity and the mechanism by which blocking macrophage-associated PD-1 causes inflammatory disorders in sepsis. MATERIALS AND METHODS: We first measured whether the expression of PD-1 on the monocyte subset is clinically associated with sepsis severity in an observational study. This study included 42 septic patients and 16 healthy controls (HCs) whose serum inflammatory factors were examined by Luminex MagPix. Then, we investigated the effect of PD-1 blockade on macrophages from septic mice (C57BL/6 mice) constructed by caecal ligation and puncture (CLP) via RNA sequencing. The positive genes screened by RNA-seq were verified in LPS-stimulated RAW264.7 cells by Western blot. RESULTS: The results showed that the expression of PD-1 on CD14+CD16+ monocytes (intermediate monocytes, IM Mo) was significantly higher in both septic and septic shock patients than in HCs. Further analysis of serum cytokines in septic patients showed that the levels of IL-6 and TNF-α were significantly higher than those in HCs, while serum PD-1 levels were decreased in septic patients. More interestingly, blockade of PD-1 on macrophages from septic mice suppressed the gene expression levels of NLRP3/Caspase-4/AKT2/STAT3. The protein levels associated with pyroptosis including NLRP3, Caspase4, GSDMD and NT-GSDMD were significantly decreased in LPS-stimulated RAW264.7 cells treated with PD-1 antibody. CONCLUSION: Our results suggested that intermediate monocytes with high expression of PD-1 may be involved in the progression of sepsis. PD-1 might play a critical role in regulating the pyroptosis signalling pathway in sepsis.
OBJECTIVE: Programmed death 1 (PD-1) and macrophages are the most intriguing candidates in sepsis-induced inflammatory disorders. We aimed to investigate the association between monocyte PD-1 and sepsis severity and the mechanism by which blocking macrophage-associated PD-1 causes inflammatory disorders in sepsis. MATERIALS AND METHODS: We first measured whether the expression of PD-1 on the monocyte subset is clinically associated with sepsis severity in an observational study. This study included 42 septic patients and 16 healthy controls (HCs) whose serum inflammatory factors were examined by Luminex MagPix. Then, we investigated the effect of PD-1 blockade on macrophages from septic mice (C57BL/6 mice) constructed by caecal ligation and puncture (CLP) via RNA sequencing. The positive genes screened by RNA-seq were verified in LPS-stimulated RAW264.7 cells by Western blot. RESULTS: The results showed that the expression of PD-1 on CD14+CD16+ monocytes (intermediate monocytes, IM Mo) was significantly higher in both septic and septic shock patients than in HCs. Further analysis of serum cytokines in septic patients showed that the levels of IL-6 and TNF-α were significantly higher than those in HCs, while serum PD-1 levels were decreased in septic patients. More interestingly, blockade of PD-1 on macrophages from septic mice suppressed the gene expression levels of NLRP3/Caspase-4/AKT2/STAT3. The protein levels associated with pyroptosis including NLRP3, Caspase4, GSDMD and NT-GSDMD were significantly decreased in LPS-stimulated RAW264.7 cells treated with PD-1 antibody. CONCLUSION: Our results suggested that intermediate monocytes with high expression of PD-1 may be involved in the progression of sepsis. PD-1 might play a critical role in regulating the pyroptosis signalling pathway in sepsis.
Authors: Eleanor A Fallon; Bethany M Biron-Girard; Chun-Shiang Chung; Joanne Lomas-Neira; Daithi S Heffernan; Sean F Monaghan; Alfred Ayala Journal: J Leukoc Biol Date: 2018-02-02 Impact factor: 4.962