P38/MAPK contributes to endothelial barrier dysfunction via MAP4 phosphorylation-dependent microtubule disassembly in inflammation-induced acute lung injury.
Excessive activation of inflammation and the accompanying lung vascular endothelial barrier disruption are primary pathogenic features of acute lung injury (ALI). Microtubule-associated protein 4 (MAP4), a tubulin assembly-promoting protein, is important for maintaining the microtubule (MT) cytoskeleton and cell-cell junctional structures. However, both the involvement and exact mechanism of MAP4 in the development of endothelial barrier disruption in ALI remains unknown. In this study, lipopolysaccharide (LPS) and tumour necrosis factor-α (TNF-α) were applied to human pulmonary microvascular endothelial cells (HPMECs) to mimic the endothelial damage during inflammation in vitro. We demonstrated that the MAP4 (Ser696 and Ser787) phosphorylation increased concomitantly with the p38/MAPK pathway activation by the LPS and TNF-α stimulation of HPMECs, which induced MT disassembly followed by hyperpermeability. Moreover, the application of taxol, the overexpression of a MAP4 (Ala) mutant, or the application of the p38/MAPK inhibitor SB203580 inhibited the MT disruption and the intracellular junction dysfunction. In contrast, MKK6 (Glu), which constitutively activated p38/MAPK, resulted in microtubule depolymerisation and, subsequently, hyperpermeability. Our findings reveal a novel role of MAP4 in endothelial barrier dysfunction.
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Lingfei
L
Li
Endocrinology Department, Southwest Hospital, Third Military Medical University, Chongqing, China.
Jiongyu
J
Hu
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Ting
T
He
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Qiong
Q
Zhang
Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
Xu
X
Yang
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Xiaodong
X
Lan
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Dongxia
D
Zhang
Department of Biostatistics in the School of Public Health, Yale University.
Hao
H
Mei
Endocrinology Department, Southwest Hospital, Third Military Medical University, Chongqing, China.
Bing
B
Chen
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China.
Yuesheng
Y
Huang
D055371:Acute Lung Injury / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism* / Q000473:pathology; D010539:Permeability; D010766:Phosphorylation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
C000601103:MAP4 protein, human; D008869:Microtubule-Associated Proteins; D048051:p38 Mitogen-Activated Protein Kinases