P019 Determinism of enteric glial reactivity in Inflammatory Bowel Disease
M. Freyssinet*, T. Clairembault, S. Coquenlorge, J. Jaulin, E. Coron, S. Bruley des Varannes, M. Neunlist, M. Rolli-Derkinderen, A. Bourreille
U913, INSERM, Neuro-Gastroenterologie, Nantes, France
In inflammatory bowel disease (IBD) patients, enteric glial cells (EGC) present some differences in the expression level of glial markers. Whether these changes are determined by the pathological environment or represent a constitutive feature of pathological EGC is unknown. The purpose of our study is (i) to determine if, ex vivo, human EGC from IBD patients present the lesions observed in vivo in healthy and non-healthy mucosal areas of Crohn's disease (CD) or ulcerative colitis (UC) patients, and (ii) to determine if an inflammatory environment can reproduce the changes observed in vivo.
Culture of human EGC from CD, UC and control patients (CONT) and biopsies of IBD patients (18 CD, 9 UC and 15 CONT ) were analyzed for glial marker expression as described hereafter. Biopsies were performed by endoscopic procedures in macroscopicaly non-inflamed mucosal area (NI) and in inflamed mucosal area (I) for each patient. Culture of human or rat EGC were subjected to chronic inflammatory stress represented by TNF α and interleukin-1 β (TI; 1ng/ml) or lipopolysacharide (LPS; 0.1µg/ml) for four days. Expression of the glial markers Sox10, S100 β and glial fibrillary acid protein (GFAP) were assessed by quantitative real time PCR and Western blot analysis.
Culture of human EGC from CD, UC and CONT did not present any significant changes in glial marker expression. TI treatment of EGC induced a significant over-expression of the three glial markers. LPS stimulation of EGC also induced an over-expression of Sox10 and S100 β but did not affect GFAP expression. Concerning the biopsies, the mRNA expression levels of Sox10 and S100 β were significantly elevated in I and NI areas of CD patients compared to CONT or UC.
“Expression of mRNA of S100 and Sox 10 is significantly increased in colonic biopsies of CD patients compared to controls and UC patients”
Intermediate isoform of GFAP was significantly increased in inflamed area of CD patients compared to controls (p=0.011).
Our work shows that glial marker expression is determined by the pathological environment and is not a constitutive feature of EGC from CD or UC patients. Secondly, we have observed that GFAP is differentially regulated by inflammatory cytokine and endotoxin. Ex vivo, the LPS reproduces the Sox10 and S100 β expression changes observed in vivo.