Chitinase 3-like 1 induces survival and proliferation of intestinal epithelial cells during chronic inflammation and colitis-associated cancer by regulating S100A9

// Daren Low 1 , Renuka Subramaniam 1 , Li Lin 2 , Tomoki Aomatsu 3 , Atsushi Mizoguchi 4 , Aylwin Ng 1 , Arianna K. DeGruttola 1 , Chun Geun Lee 5 , Jack A. Elias 5 , Akira Andoh 3 , Mari Mino-Kenudson 6 , Emiko Mizoguchi 1, 7 1 Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA 2 Laboratory of Cardiovascular Science, National Institutes on Aging, National Institutes of Health, Baltimore, MD, USA 3 Division of Mucosal Immunology, Graduate School, Shiga University of Medical Science, Seta Tsukinowa, Otsu, Shiga, Japan 4 Department of Immunology, Kurume University School of Medicine, Kurume, Fukuoka, Japan 5 Department of Microbiology and Immunology, Warren Alpert School of Medicine, Brown University, Providence, RI, USA 6 Department of Pathology & Cancer Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA 7 Center for The Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA Correspondence to: Emiko Mizoguchi, e-mail: emizoguchi@mgh.harvard.edu Keywords: mammalian chitinase, colitis-associated cancer, bone marrow chimeras, RAGE, intestinal epithelial cells Received: August 17, 2015      Accepted: September 16, 2015      Published: September 28, 2015 ABSTRACT Many host-factors are inducibly expressed during the development of inflammatory bowel disease (IBD), each having their unique properties, such as immune activation, bacterial clearance, and tissue repair/remodeling. Dysregulation/imbalance of these factors may have pathogenic effects that can contribute to colitis-associated cancer (CAC). Previous reports showed that IBD patients inducibly express colonic chitinase 3-like 1 (CHI3L1) that is further upregulated during CAC development. However, little is known about the direct pathogenic involvement of CHI3L1 in vivo . Here we demonstrate that CHI3L1 (aka Brp39) knockout (KO) mice treated with azoxymethane (AOM)/dextran sulphate sodium (DSS) developed severe colitis but lesser incidence of CAC as compared to that in wild-type (WT) mice. Highest CHI3L1 expression was found during the chronic phase of colitis, rather than the acute phase, and is essential to promote intestinal epithelial cell (IEC) proliferation in vivo . This CHI3L1-mediated cell proliferation/survival involves partial downregulation of the pro-apoptotic S100A9 protein that is highly expressed during the acute phase of colitis, by binding to the S100A9 receptor, RAGE (Receptor for Advanced Glycation End products). This interaction disrupts the S100A9-associated expression positive feedback loop during early immune activation, creating a CHI3L1 hi S100A9 low colonic environment, especially in the later phase of colitis, which promotes cell proliferation/survival of both normal IECs and tumor cells.