title: TNF-α mediated increase of HIF-1α inhibits VASP expression, which reduces alveolar-capillary barrier function during acute lung injury (ALI).
abstract: Acute lung injury (ALI) is an inflammatory disorder associated with reduced alveolar-capillary barrier function and increased pulmonary vascular permeability. Vasodilator-stimulated phosphoprotein (VASP) is widely associated with all types of modulations of cytoskeleton rearrangement-dependent cellular morphology and function, such as adhesion, shrinkage, and permeability. The present studies were conducted to investigate the effects and mechanisms by which tumor necrosis factor-alpha (TNF-α) increases the tight junction permeability in lung tissue associated with acute lung inflammation. After incubating A549 cells for 24 hours with different concentrations (0-100 ng/mL) of TNF-α, 0.1 to 8 ng/mL TNF-α exhibited no significant effect on cell viability compared with the 0 ng/mL TNF-α group (control group). However, 10 ng/mL and 100 ng/mL TNF-α dramatically inhibited the viability of A549 cells compared with the control group (*p<0.05). Monolayer cell permeability assay results indicated that A549 cells incubated with 10 ng/mL TNF-α for 24 hours displayed significantly increased cell permeability (*p<0.05). Moreover, the inhibition of VASP expression increased the cell permeability (*p<0.05). Pretreating A549 cells with cobalt chloride (to mimic a hypoxia environment) increased protein expression level of hypoxia inducible factor-1α (HIF-1α) (*p<0.05), whereas protein expression level of VASP decreased significantly (*p<0.05). In LPS-induced ALI mice, the concentrations of TNF-α in lung tissues and serum significantly increased at one hour, and the value reached a peak at four hours. Moreover, the Evans Blue absorption value of the mouse lung tissues reached a peak at four hours. The HIF-1α protein expression level in mouse lung tissues increased significantly at four hours and eight hours (**p<0.001), whereas the VASP protein expression level decreased significantly (**p<0.01). Taken together, our data demonstrate that HIF-1α acts downstream of TNF-α to inhibit VASP expression and to modulate the acute pulmonary inflammation process, and these molecules play an important role in the impairment of the alveolar-capillary barrier.
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China; Hunan Provincial Tumor Hospital, the Affiliated Tumor Hospital of Xiangya Medical School of Central South University, Changsha, Hunan, PR China.
authors: Mengjie
authors: M
authors: Tang
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Yihao
authors: Y
authors: Tian
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Doulin
authors: D
authors: Li
authors: Zhongnan Hospital of Wuhan University, the Second College of Clinical Medicine of Wuhan University, Wuhan, Hubei, PR China.
authors: Jiawei
authors: J
authors: Lv
authors: Renmin Hospital of Wuhan University, the First College of Clinical Medicine of Wuhan University, Wuhan, Hubei, PR China.
authors: Qun
authors: Q
authors: Li
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Changchun
authors: C
authors: Kuang
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Pengchao
authors: P
authors: Hu
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Ying
authors: Y
authors: Wang
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Jing
authors: J
authors: Wang
authors: Renmin Hospital of Wuhan University, Division of Nephrology, Wuhan, Hubei, PR China.
authors: Ke
authors: K
authors: Su
authors: Department of Pathology and Pathophysiology, Research Center of Food and Drug Evaluation, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, PR China.
authors: Lei
authors: L
authors: Wei
mesh_terms: D055371:Acute Lung Injury / Q000139:chemically induced / Q000235:genetics* / Q000503:physiopathology; D000818:Animals; D015153:Blotting, Western; D002196:Capillaries / Q000378:metabolism* / Q000503:physiopathology; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides; D008807:Mice, Inbred BALB C; D008840:Microfilament Proteins / Q000235:genetics* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000098:blood supply / Q000378:metabolism / Q000503:physiopathology; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008070:Lipopolysaccharides; D008840:Microfilament Proteins; D010750:Phosphoproteins; D014409:Tumor Necrosis Factor-alpha; D000098662:Vasodilator-Stimulated Phosphoprotein