title: Vitamin D/VDR signaling attenuates lipopolysaccharide‑induced acute lung injury by maintaining the integrity of the pulmonary epithelial barrier.
abstract: Vitamin D and its receptor have a protective effect on epithelial barriers in various tissues. Low levels of vitamin D are associated with numerous pulmonary diseases, including acute lung injury (ALI) and acute respiratory distress syndrome. The present study investigated whether the vitamin D/vitamin D receptor (VDR) pathway may ameliorate lipopolysaccharide (LPS)‑induced ALI through maintaining the integrity of the alveolar epithelial barrier. This was investigated by exposing wild‑type (WT) and VDR knockout C57BL/6J mice to LPS, then comparing the healthy and LPS‑treated mice lungs and bronchoalveolar lavage fluid (BALF). More specifically, lung histology, mRNA levels of proinflammatory cytokines and chemokines, and protein expression levels of tight junction proteins were determined. In addition, a vitamin D analog (paricalcitol) was administered to WT mice in order to investigate the effect of vitamin D on the alveolar epithelial barrier following exposure to LPS. VDR knockout mice exhibited severe lung injuries (P<0.001), increased alveolar permeability [demonstrated by a higher wet‑dry ratio of lung weight (P<0.05), greater expression levels of BALF protein (P<0.001) and fluorescein isothiocyanate‑conjugated 4 kDa dextran (P<0.001) leakage into the alveolar space], elevated proinflammatory cytokine and chemokine mRNA levels, as demonstrated by reverse transcription‑quantitative polymerase chain reaction (P<0.05), and decreased protein and mRNA expression levels of occludin (P<0.01) and zonula occludens‑1 (ZO‑1; P<0.01) compared with WT mice. Paricalcitol treatment partially inhibited these pathological changes in WT mice by maintaining the mRNA and protein expression levels of occludin (P<0.01) and ZO‑1 (P<0.05). A lack of VDRs in the pulmonary epithelial barrier appeared to compromise its defense, leading to more severe LPS‑induced lung injury. Furthermore, vitamin D treatment alleviated LPS‑induced lung injury and preserved alveolar barrier function. Therefore vitamin D treatment may present as a potential therapeutic strategy in ALI and acute respiratory distress syndrome.
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Yong-Yan
authors.initials: YY
authors.lastname: Shi
authors.affiliation: Department of Pediatric Orthopedics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Tian-Jing
authors.initials: TJ
authors.lastname: Liu
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Fu
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Lin-Lin
authors.initials: LL
authors.lastname: Wu
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: A-Na
authors.initials: AN
authors.lastname: Hou
authors.affiliation: Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Xin-Dong
authors.initials: XD
authors.lastname: Xue
mesh_terms: D055371:Acute Lung Injury / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D004848:Epithelium / Q000473:pathology*; D008070:Lipopolysaccharides; D008168:Lung / Q000473:pathology*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D062793:Occludin / Q000378:metabolism; D011014:Pneumonia / Q000150:complications / Q000473:pathology; D011654:Pulmonary Edema / Q000150:complications / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism*; D015398:Signal Transduction; D019108:Tight Junctions / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D018925:Chemokines; D008070:Lipopolysaccharides; D062793:Occludin; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D062826:Zonula Occludens-1 Protein; D014807:Vitamin D