title: High Mobility Group Box Protein 1 Boosts Endothelial Albumin Transcytosis through the RAGE/Src/Caveolin-1 Pathway.
abstract: High-mobility group box protein 1 (HMGB1), an inflammatory mediator, has been reported to destroy cell-cell junctions, resulting in vascular endothelial hyperpermeability. Here, we report that HMGB1 increases the endothelial transcytosis of albumin. In mouse lung vascular endothelial cells (MLVECs), HMGB1 at a concentration of 500 ng/ml or less did not harm cell-cell junctions but rapidly induced endothelial hyperpermeability to (125)I-albumin. HMGB1 induced an increase in (125)I-albumin and AlexaFluor 488-labeled albumin internalization in endocytosis assays. Depletion of receptor for advanced glycation end products (RAGE), but not TLR2 or TLR4, suppressed HMGB1-induced albumin transcytosis and endocytosis. Genetic and pharmacological destruction of lipid rafts significantly inhibited HMGB1-induced albumin endocytosis and transcytosis. HMGB1 induced the rapid phosphorylation of caveolin (Cav)-1 and Src. Either RAGE gene silencing or soluble RAGE suppressed Cav-1 Tyr14 phosphorylation and Src Tyr418 phosphorylation. The Src inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2) blocked HMGB1-induced Cav-1 Tyr14 phosphorylation. PP2 and overexpression of Cav-1 with a T14F mutation significantly inhibited HMGB1-induced transcytosis and albumin endocytosis. Our findings suggest that HMGB1 induces the transcytosis of albumin via RAGE-dependent Src phosphorylation and Cav-1 phosphorylation. These studies revealed a new mechanism of HMGB1-induced endothelial hyperpermeability.
authors: Department of Vascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Dan
authors: D
authors: Shang
authors: Department of Pancreatic surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Tao
authors: T
authors: Peng
authors: Department of Pancreatic surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Shanmiao
authors: S
authors: Gou
authors: Department of Vascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Yiqing
authors: Y
authors: Li
authors: Department of Pancreatic surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Heshui
authors: H
authors: Wu
authors: Department of Pancreatic surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Chunyou
authors: C
authors: Wang
authors: Department of Pancreatic surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
authors: Zhiyong
authors: Z
authors: Yang
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000502:physiology; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D024243:HMGB1 Protein / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation / Q000502:physiology; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism*; D000067759:Receptor for Advanced Glycation End Products / Q000235:genetics / Q000378:metabolism*; D012709:Serum Albumin / Q000235:genetics / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D057900:Transcytosis / Q000502:physiology*
chemical_list: C000593873:Ager protein, mouse; C495541:Cav1 protein, mouse; D051242:Caveolin 1; D024243:HMGB1 Protein; C582808:HMGB1 protein, mouse; D000067759:Receptor for Advanced Glycation End Products; D012709:Serum Albumin; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D016392:Proto-Oncogene Proteins pp60(c-src)