Rachel G. Scheraga, MD Cleveland Clinic Cleveland, OH The Mechanosensitive TRPV4 Ion Channel Mediates the Pro-resolution/Anti-fibrotic Macrophage Response to LPS Rachel G. Scheraga, MD Cleveland Clinic Cleveland, OH

Bacterial pneumonia in Idiopathic pulmonary fibrosis (IPF) Recurrent pneumonia in IPF patients causes progressive decline in lung function Infection-associated lung injury leads to edema and inflammatory cell infiltration causing increased matrix stiffness and secretion of cytokines Molyneaux et al. Am J Respir Crit Care Med, 2014 Murray et al. Nat Rev Immunol , 2001 Wynn et al. Nature, 2013

Macrophage phagocytosis Critical to lung host defense and lung injury, repair, and fibrosis Requires orchestration of macrophage surface receptors, the particle itself, and extracellular matrix Rougerie et al. Immunol. Rev, 2013 Wynn et al. Nature, 2013 Blakney et al. J Biomed Mater Res A, 2012

Transient receptor potential vanilloid 4 (TRPV4) Mechanosensitive cation-permeable channel that is activated by chemical and physical stimuli, including plasma membrane stretching Ubiquitous cell type and tissue expression Our lab is the first to investigate the significance of TRPV4 in lung fibrosis Montell et al. Cell, 2002; Everaerts et al; Prog Biophys Mol Biol, 2010

Hypothesis TRPV4 integrates the extracellular matrix stiffness and LPS signals to mediate infection-associated lung injury and repair

TRPV4 mediates macrophage phagocytosis of IgG-coated beads WT-UT TRPV4 KO-UT WT-LPS + * * * TRPV4 KO-LPS Scheraga et al. J Immunol, In press

TRPV4 mediates macrophage phagocytosis of E. coli particles BMDM AM + + * * * * Scheraga et al. J Immunol, In press

The TRPV4-mediated phagocytic effect depends on matrix stiffness + + # # # # Scheraga et al. J Immunol, In press

TRPV4 modulates an anti-inflammatory cytokine profile in response to LPS * (% b * Scheraga et al. J Immunol, In press

TRPV4 mediates macrophage phagocytosis of IgG-coated beads in live mice Saline LPS WT + * KO Scheraga et al. J Immunol, In press

TRPV4 limits lung injury and initiates resolution in a bacterial pneumonia model Day 3 Day 8 * (mg/mL)

Conclusions These data suggest : TRPV4 mediates the phagocytic and cytokine profile response to infection stiffness-dependent manner May play a role in progressive fibrosis seen in patients with IPF after infection

Acknowledgements Cleveland Clinic - Pathobiology Dr. Mitchell Olman Dr. Brian Southern Dr. Lisa Grove Susamma Abraham Kathryn Niese Cleveland Clinic - Immunology Dr. Thomas Hamilton Dr. Chenyang Zhao Dr. Olman’s Lab

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