Simultaneously Targeting Myofibroblast Contractility and Extracellular Matrix Cross-Linking as a Therapeutic Concept in Airway Fibrosis.
Fibrosis after solid organ transplantation is considered an irreversible process and remains the major cause of graft dysfunction and death with limited therapies. This remodeling is characterized by aberrant accumulation of contractile myofibroblasts that deposit excessive extracellular matrix (ECM) and increase tissue stiffness. Studies demonstrate, however, that a stiff ECM itself promotes fibroblast-to-myofibroblast differentiation, stimulating further ECM production. This creates a positive feedback loop that perpetuates fibrosis. We hypothesized that simultaneously targeting myofibroblast contractility with relaxin and ECM stiffness with lysyl oxidase inhibitors could break the feedback loop, reversing established fibrosis. To test this, we used the orthotopic tracheal transplantation (OTT) mouse model, which develops robust fibrotic airway remodeling. Mice with established fibrosis were treated with saline, mono-, or combination therapies. Although monotherapies had no effect, combining these agents decreased collagen deposition and promoted re-epithelialization of remodeled airways. Relaxin inhibited myofibroblast differentiation and contraction in a matrix-stiffness-dependent manner through prostaglandin E2(PGE2). Furthermore, the effect of combination therapy was lost in PGE2receptor knockout and PGE2-inhibited OTT mice. This study revealed the important synergistic roles of cellular contractility and tissue stiffness in the maintenance of fibrotic tissue and suggests a new therapeutic principle for fibrosis.
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA.|Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
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Lin
Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
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Sung
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA.|Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
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Jiang
Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Michigan, Ann Arbor, Ann Arbor, MI.
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Peters-Golden
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA.|Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
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Nicolls
D000818:Animals; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects*; D058628:Myofibroblasts / Q000187:drug effects* / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000517:prevention & control*; D012065:Relaxin / Q000494:pharmacology*; D014132:Trachea / Q000637:transplantation*
D012065:Relaxin
animal models: murine; basic (laboratory) research/science; fibrosis; lung (allograft) function/dysfunction; lung biology; lung transplantation/pulmonology; organ transplantation in general; rejection: chronic; translational research/science