Stephanie L C Scofield1, Christopher R Daniels1, Suman Dalal2, Jonathan A Millard1, Mahipal Singh1, Krishna Singh3. 1. Department of Biomedical Sciences, James H Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States of America. 2. Department of Biomedical Sciences, James H Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States of America; Center of Excellence for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN 37614, United States of America. 3. Department of Biomedical Sciences, James H Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States of America; Center of Excellence for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN 37614, United States of America; James H Quillen Veterans Affairs Medical Center, Mountain Home, TN 37684, United States of America. Electronic address: singhk@etsu.edu.
Abstract
AIMS: β-adrenergic receptor (β-AR) stimulation increases extracellular levels of ubiquitin (UB), and exogenous UB plays an important role in β-AR-stimulated myocardial remodeling with effects on heart function, fibrosis and myocyte apoptosis. Cardiac fibroblasts are vital for maintaining the normal function of the heart, and in the structural remodeling of the heart in response to injury. Here we hypothesized that extracellular UB modulates cardiac fibroblast phenotype and function via its interaction with CXC chemokine receptor type 4 (CXCR4). MAIN METHODS: Serum starved adult cardiac fibroblasts were used to identify CXCR4 as a receptor for UB. Fluorescent microscopy, co-immunoprecipitation, western blot, proliferation, migration and collagen contraction assays were performed to investigate the role of UB/CXCR4 axis on cell signaling, and modulation of fibroblast phenotype and function. KEY FINDINGS: Using fluorescent microscopy and co-immunoprecipitation assay, we provide evidence that extracellular UB interacts with CXCR4. CXCR4 antagonist, AMD3100, inhibited interaction of UB with CXCR4. UB activated ERK1/2, not Akt. It enhanced VEGF-A expression, while decreasing β3 integrins expression. Two mutated UB proteins (V70A and F4A; unable to interact with CXCR4) failed to affect the expression of VEGF-A and β3 integrins. UB treatment inhibited migration of cells into the wound and FBS-stimulated cell proliferation. UB enhanced expression of α-smooth muscle actin (marker of myofibroblast differentiation) and contraction of fibroblast-populated collagen gel pads. Most of the effects of UB were negated by AMD3100. SIGNIFICANCE: The data presented here suggest that UB interacts with CXCR4, and UB/CXCR4 interaction affects intracellular signaling, and modulates fibroblast phenotype and function. Published by Elsevier Inc.
AIMS: β-adrenergic receptor (β-AR) stimulation increases extracellular levels of ubiquitin (UB), and exogenous UB plays an important role in β-AR-stimulated myocardial remodeling with effects on heart function, fibrosis and myocyte apoptosis. Cardiac fibroblasts are vital for maintaining the normal function of the heart, and in the structural remodeling of the heart in response to injury. Here we hypothesized that extracellular UB modulates cardiac fibroblast phenotype and function via its interaction with CXC chemokine receptor type 4 (CXCR4). MAIN METHODS: Serum starved adult cardiac fibroblasts were used to identify CXCR4 as a receptor for UB. Fluorescent microscopy, co-immunoprecipitation, western blot, proliferation, migration and collagen contraction assays were performed to investigate the role of UB/CXCR4 axis on cell signaling, and modulation of fibroblast phenotype and function. KEY FINDINGS: Using fluorescent microscopy and co-immunoprecipitation assay, we provide evidence that extracellular UB interacts with CXCR4. CXCR4 antagonist, AMD3100, inhibited interaction of UB with CXCR4. UB activated ERK1/2, not Akt. It enhanced VEGF-A expression, while decreasing β3 integrins expression. Two mutated UB proteins (V70A and F4A; unable to interact with CXCR4) failed to affect the expression of VEGF-A and β3 integrins. UB treatment inhibited migration of cells into the wound and FBS-stimulated cell proliferation. UB enhanced expression of α-smooth muscle actin (marker of myofibroblast differentiation) and contraction of fibroblast-populated collagen gel pads. Most of the effects of UB were negated by AMD3100. SIGNIFICANCE: The data presented here suggest that UB interacts with CXCR4, and UB/CXCR4 interaction affects intracellular signaling, and modulates fibroblast phenotype and function. Published by Elsevier Inc.
Authors: James J Tomasek; Giulio Gabbiani; Boris Hinz; Christine Chaponnier; Robert A Brown Journal: Nat Rev Mol Cell Biol Date: 2002-05 Impact factor: 94.444
Authors: Karl Balabanian; Bernard Lagane; Simona Infantino; Ken Y C Chow; Julie Harriague; Barbara Moepps; Fernando Arenzana-Seisdedos; Marcus Thelen; Françoise Bachelerie Journal: J Biol Chem Date: 2005-08-17 Impact factor: 5.157
Authors: Stephanie L C Scofield; Suman Dalal; Kristina A Lim; Patsy R Thrasher; Christopher R Daniels; Jonathan M Peterson; Mahipal Singh; Krishna Singh Journal: Am J Physiol Heart Circ Physiol Date: 2019-01-25 Impact factor: 4.733