{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent studies have identified SFTA3 as a novel surfactant-associated protein with important immunoregulatory functions in the lung. SFTA3 is expressed in alveolar type II cells and appears to participate in the innate immune defense by modulating the alveolar response to pathogens. In vitro, lipopolysaccharide (LPS) stimulates its expression, suggesting that SFTA3 may be upregulated during bacterial challenge, whereas key inflammatory cytokines such as interleukin‑1β and interleukin‑23 suppress its production. This cytokine-regulated expression pattern points to a role for SFTA3 in fine‐tuning local immune responses to maintain pulmonary homeostasis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its pulmonary functions, SFTA3 is also expressed at the ocular surface. Studies using human corneal and conjunctival epithelial cell lines have demonstrated that SFTA3 contributes to effective wound healing by accelerating cell migration, a process that is critical for epithelial repair. Moreover, recombinant SFTA3 has been observed to reduce the surface tension of tear fluid, which may help stabilize the tear film—a function that becomes particularly relevant in the context of dry eye disease, where SFTA3 levels are significantly increased."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nBioinformatic analyses and initial molecular characterization further support the inclusion of SFTA3 among lung surfactant proteins, despite its distinct primary structure compared to classical surfactant proteins. Advances in recombinant protein synthesis and stabilization techniques have enabled a more detailed study of SFTA3’s structure and potential mechanisms of action. These developments promise to expand our understanding of how SFTA3 contributes to both surfactant regulation and mucosal defense, potentially offering new therapeutic angles for pulmonary and ocular inflammatory conditions."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}]}]}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Martin Schicht, Felix Rausch, Susetta Finotto, et al. "}, {"type": "b", "children": [{"type": "t", "text": "SFTA3, a novel protein of the lung: three-dimensional structure, characterisation and immune activation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Eur Respir J (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1183/09031936.00179813"}], "href": "https://doi.org/10.1183/09031936.00179813"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "24743970"}], "href": "https://pubmed.ncbi.nlm.nih.gov/24743970"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Martin Schicht, Fabian Garreis, Nadine Hartjen, et al. "}, {"type": "b", "children": [{"type": "t", "text": "SFTA3 - a novel surfactant protein of the ocular surface and its role in corneal wound healing and tear film surface tension."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2018)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-018-28005-9"}], "href": "https://doi.org/10.1038/s41598-018-28005-9"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "29955092"}], "href": "https://pubmed.ncbi.nlm.nih.gov/29955092"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "H Schröder, R Fischer, L Sollfrank, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Expression of recombinant surfactant protein SFTA3 in the human kidney cell line HEK 293T."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Ann Anat (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.aanat.2017.01.005"}], "href": "https://doi.org/10.1016/j.aanat.2017.01.005"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28163207"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28163207"}]}]}]}