title: Silencing of triggering receptor expressed on myeloid cells-2 enhances             the inflammatory responses of alveolar macrophages to lipopolysaccharide.
abstract: Triggering receptor expressed on myeloid cells-2 (TREM-2) has been shown to attenuate inflammatory responses in various cell lines including bone marrow-derived macrophages, hepatic macrophages, osteoclasts and dendritic cells. However, its effects on alveolar macrophages remain unknown. Lentivirus-mediated RNA interference (RNAi) is a post-transcriptional gene silencing method, which is capable of degrading target genes specifically and efficiently. In this study, we silenced TREM-2 in murine alveolar macrophages by using lentivirus-mediated short hairpin RNA (shRNA) and evaluated the effects of TREM-2 silencing on expression of toll-like receptor-4 (TLR-4), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in response to lipopolysaccharide (LPS). Alveolar macrophages were transfected with shRNA targeting TREM-2 by use of lentivirus vector, non-sense shRNA as a negative control or empty lentivirus vector as a blank control. Silencing of TREM-2 was assessed by real‑time fluorescence quantitative PCR and flow cytometry. Following LPS stimulation, the levels of TLR-4, TNF-α and IL-10 expressed in alveolar macrophages were measured by real-time PCR, flow cytometry or ELISA. TREM-2 expression on alveolar macrophages was downregulated significantly by lentivirus-mediated shRNA treatment at the transcriptional and translational levels. However, alveolar macrophages that received non-sense shRNA or empty lentivirus vectors showed no effects on TREM-2 expression. Silencing of TREM-2 enhanced expression of TLR-4, as well as TNF-α and IL-10, by alveolar macrophages following LPS stimulation. These results indicate a significant effect of TREM-2 on attenuating the LPS-induced inflammatory response of murine alveolar macrophages, which may be dependent on TLR-4.
authors: Department of Respiratory, The Second Hospital of Shanxi Medical University, Taiyuan 030001, PR China.
authors: Xiaoling
authors: X
authors: Gao
authors: Yanting
authors: Y
authors: Dong
authors: Zhuola
authors: Z
authors: Liu
authors: Bo
authors: B
authors: Niu
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005822:Genetic Vectors / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D008070:Lipopolysaccharides / Q000633:toxicity*; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D034741:RNA, Small Interfering; D011971:Receptors, Immunologic; D051197:Toll-Like Receptor 4; C498716:Trem2 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10