{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent studies have revealed that the tetraspan protein MS4A6D is specifically expressed in mononuclear phagocytes where it operates as a critical adapter molecule. Under normal and inflammatory conditions, its expression is controlled by transcription factors such as NKX2-1, and it localizes predominantly to macrophages, where it is poised to modulate inflammatory responses. These findings, derived from an endotoxin challenge model, indicate that the presence of MS4A6D influences the survival outcome of mice by modulating the downstream inflammatory cascade."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nAt the molecular level, MS4A6D proteins form homodimers through a critical cysteine residue (Cys237) and are further activated by MHC class II engagement. This interaction triggers the phosphorylation of a key tyrosine residue (Tyr241) present in its hemITAM-like motif, thereby initiating a SYK-CREB signaling cascade. This cascade boosts the transcription of proinflammatory cytokines—including Il1b, Il6, and Tnfa—and increases mitochondrial reactive oxygen species (mtROS) production. Importantly, genetic ablation or mutation of these critical residues (C237 and Tyr241) markedly dampens the inflammatory response, as evidenced by improved survival in endotoxin-induced shock models."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn a complementary experimental model, MS4A6D was shown to exacerbate acute inflammatory responses, such as carrageenan-induced footpad swelling. In these studies, MS4A6D deficiency resulted in significantly reduced macrophage infiltration and lower secretion of IL-1β, a key cytokine produced following NLRP3 inflammasome activation. Both the interruption of MS4A6D homodimerization and deletion of the regulatory Tyr241 site led to diminished NLRP3 inflammasome activity in macrophages, underscoring the protein's role as an enhancer of macrophage-derived inflammation. These findings suggest that targeting MS4A6D could provide a beneficial strategy in treating macrophage-associated inflammatory disorders."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Yue Chen, Sirui Li, Xiaoyong Huang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Tetraspan MS4A6D is a coreceptor of MHC class II antigen (MHC-II) that promotes macrophages-derived inflammation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Immunol (2023)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.molimm.2023.07.003"}], "href": "https://doi.org/10.1016/j.molimm.2023.07.003"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "37429063"}], "href": "https://pubmed.ncbi.nlm.nih.gov/37429063"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Jing Guo, Chenhui Wang, Qun Xiang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "MS4A6D Promotes carrageenan-induced footpad swelling in mice through enhancing macrophages-derived inflammation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Immunol (2024)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.molimm.2024.03.001"}], "href": "https://doi.org/10.1016/j.molimm.2024.03.001"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "38493579"}], "href": "https://pubmed.ncbi.nlm.nih.gov/38493579"}]}]}]}