EGCG induces G-CSF expression and neutrophilia in experimental sepsis
IMMUNOLOGIC RESEARCH
Authors: Li, Wei; Wu, Andrew H.; Zhu, Shu; Li, Jianhua; Wu, Rong; D'Angelo, John; Wang, Haichao
Abstract
A major green tea component, epigallocatechin-3-gallate (EGCG), has been proven protective against lethal sepsis in experimental setting, but its protective mechanisms remain incompletely understood. Here, we provide evidence to support EGCG's capacities in stimulating G-CSF production and neutrophilia in vivo. In an animal model of sepsis, EGCG significantly elevated peritoneal levels of G-CSF and several chemokines (e.g., MCP-1/CCL2 and MIP-1 gamma/CCL9), and consequently increased peritoneal neutrophil numbers (neutrophilia) at a late stage. In vitro, EGCG divergently affected HMGB1-mediated production of several chemokines: reducing CXCL15 and RANTES/CCL5, but elevating G-CSF and MIP-1 alpha/CCL3 production by peritoneal macrophages. Similarly, it significantly induced the expression and secretion of G-CSF and MIP-1 alpha/CCL3 in human peripheral blood mononuclear cells. Based on our preliminary data, it may be important to search for anti-inflammatory and G-CSF-stimulating agents for the clinical management of inflammatory diseases.
Resveratrol decreases CD45(+)CD206(-) subtype macrophages in LPS-induced murine acute lung injury by SOCS3 signalling pathway
JOURNAL OF CELLULAR AND MOLECULAR MEDICINE
Authors: Hu, Lu; Chen, Zhihong; Li, Liyang; Jiang, Zhilong; Zhu, Lei
Abstract
Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are life-threatening condition in critically ill patients. Resveratrol (Res), a natural polyphenol, has therapeutic effect in animal model with ALI; however, whether Res attenuates ALI through modulation of macrophage phenotypes in the animal model remains unknown. We in this study treated LPS-induced murine ALI with 30 mg/kg Res and observed significantly reduced severity of ALI in the Res-treated mice 48 hours after Res treatment. Neutrophil infiltrates were significantly reduced, accompanied with lower infiltration of CD45(+)Siglec F- phenotype macrophages, but higher population of CD45(+)Siglec F+ and CD45(+)CD206(+) alternatively activated macrophages (M2 cells) in the Res-treated mice with ALI. In addition, the expression of IL-1beta and CXCL15 cytokines was suppressed in the treated mice. However, Res treatment in mice with myeloid cell-restricted SOCS3 deficiency did not significantly attenuate ALI severity and failed to increase population of both CD45(+)Siglec F+ and CD45(+)CD206(+) M2 subtype macrophages in the murine ALI. Further studies in wild-type macrophages revealed that Res treatment effectively reduced the expression of IL-6 and CXCL15, and increased the expression of arginase-1, SIRT1 and SOCS3. However, macrophages' lack of SOCS3 expression were resistant to the Res-induced suppression of IL-6 and CXCL15 in vitro. Thus, we conclude that Res suppressed CD45(+)Siglec F- and CD45(+)CD206(-) M1 subtype macrophages through SOCS3 signalling in the LPS-induced murine ALI.