Increased activation of latent TGF-β1 by αVβ3 in human Crohn's disease and fibrosis in TNBS colitis can be prevented by cilengitide.
BACKGROUND
Strictures develop in >30% of patients affected with Crohn's disease. No available medication prevents stricture development in susceptible patients. In Crohn's strictures, but not adjacent normal intestine, TGF-β1 increases in muscularis smooth muscle, increasing collagen I production and strictures. Muscle cells express αVβ3 integrin containing an Arg-Gly-Asp (RGD) binding domain. The aim was to determine whether increased TGF-β1 levels in strictures were the result of latent TGF-β1, which contains an RGD sequence, binding to and activation by αVβ3; and whether cilengitide, which is an RGD-containing αVβ3 integrin inhibitor, decreases TGF-β1 activation and development of fibrosis in chronic 2,4,6 trinitrobenzene sulfonic acid (TNBS)-induced colitis.


METHODS
Muscle cells isolated from Crohn's disease strictures and normal resection margin and from the colon of rats after 42 days of chronic TNBS-induced colitis were used to prepare RNA and protein lysates and to initiate primary cultures. The mechanisms leading to increased TGF-β1 activation, collagen I production, and fibrosis were examined in human muscle and in rats. Human cultured cells in vitro and rats in vivo were treated with cilengitide to determines it efficacy to decrease TGF-β1-activation, collagen production, and decrease the development of fibrosis.


RESULTS
Latent TGF-β1 is activated by the αVβ3 RGD domain in human and rat intestinal smooth muscles. Increased activation of TGF-β1 in Crohn's disease and in TNBS-induced colitis causes increased collagen production, and fibrosis that could be inhibited by cilengitide.


CONCLUSIONS
Cilengitide, an αVβ3 integrin RGD inhibitor, could be a novel treatment to diminish excess TGF-β1 activation, collagen I production, and development of fibrosis in Crohn's disease.
Departments of *Medicine, †Physiology and Biophysics, and ‡Surgery, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA.
Chao
C
Li
Robert S
RS
Flynn
John R
JR
Grider
Karnam S
KS
Murthy
John M
JM
Kellum
Homayoon
H
Akbari
John F
JF
Kuemmerle
D000328:Adult; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D003424:Crohn Disease / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005355:Fibrosis / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012910:Snake Venoms / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D014302:Trinitrobenzenesulfonic Acid / Q000633:toxicity; D055815:Young Adult
D016207:Cytokines; D039302:Integrin alphaVbeta3; D012333:RNA, Messenger; D012910:Snake Venoms; D053773:Transforming Growth Factor beta1; C422910:Cilengitide; D014302:Trinitrobenzenesulfonic Acid