title: High-mobility group box 1 promotes extracellular matrix synthesis and wound repair in human bronchial epithelial cells.
abstract: High mobility group box 1 (HMGB1) is a damage-associated molecular pattern (DAMP) protein that binds Toll-like receptors (e.g., TLR4) and the receptor for advanced glycated end products (RAGE). The direct effects of HMGB1 on airway structural cells are not fully known. As epithelial cell responses are fundamental drivers of asthma, including abnormal repair-restitution linked to changes in extracellular matrix (ECM) synthesis, we tested the hypothesis that HMGB1 promotes bronchial epithelial cell wound repair via TLR4 and/or RAGE signaling that regulates ECM (fibronectin and the γ2-chain of laminin-5) and integrin protein abundance. To assess impact of HMGB1 we used molecular and pharmacological inhibitors of RAGE or TLR4 signaling in scratch wound, immunofluorescence, and immunoblotting assays to assess wound repair, ECM synthesis, and phosphorylation of intracellular signaling. HMGB1 increased wound closure, and this effect was attenuated by blocking RAGE and TLR4 signaling. HMGB1-induced fibronectin and laminin-5 (γ2 chain) was diminished by blocking RAGE and/or blunting TLR4 signaling. Similarly, induction of α3-integrin receptor for fibronectin and laminin-5 was also diminished by blocking TLR4 signaling and RAGE. Lastly, rapid and/or sustained phosphorylation of SMAD2, ERK1/2, and JNK signaling modulated HMGB1-induced wound closure. Our findings suggest a role for HMGB1 in human airway epithelial cell repair and restitution via multiple pathways mediated by TLR4 and RAGE that underpin increased ECM synthesis and modulation of cell-matrix adhesion.
authors.affiliation: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors.forename: Oluwaseun O
authors.initials: OO
authors.lastname: Ojo
authors.affiliation: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors.forename: Min Hyung
authors.initials: MH
authors.lastname: Ryu
authors.affiliation: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors.forename: Aruni
authors.initials: A
authors.lastname: Jha
authors.affiliation: Department of Internal Medicine,University of Manitoba, Winnipeg, Manitoba, Canada; Section of Thoracic Surgery, University of Manitoba, Winnipeg, Manitoba, Canada; and.
authors.forename: Helmut
authors.initials: H
authors.lastname: Unruh
authors.affiliation: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Internal Medicine,University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada andrew.halayko@umanitoba.ca.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
mesh_terms: D000368:Aged; D000818:Animals; D001980:Bronchi / Q000473:pathology*; D002460:Cell Line; D004847:Epithelial Cells / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D014176:Protein Biosynthesis; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology; D000067759:Receptor for Advanced Glycation End Products / Q000378:metabolism; D051899:Smad2 Protein / Q000378:metabolism; D014019:Tissue Donors; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014945:Wound Healing
chemical_list: D016326:Extracellular Matrix Proteins; D024243:HMGB1 Protein; D000067759:Receptor for Advanced Glycation End Products; D051899:Smad2 Protein; D051197:Toll-Like Receptor 4; D020928:Mitogen-Activated Protein Kinases
keywords: COPD; DAMP; RAGE; TLR4; Toll-like receptor 4; asthma; damage-associated molecular pattern protein; extracellular matrix; receptor for advanced glycated end products