Inhibitors of Arg-Gly-Asp-Binding Integrins Reduce Development of Pancreatic Fibrosis in Mice.
OBJECTIVE
Pancreatic stellate cells (PSCs) regulate the development of chronic pancreatitis (CP) and are activated by the cytokine transforming growth factor β (TGFB). Integrins of the αv family promote TGFB signaling in mice, probably by interacting with the Arg-Gly-Asp (RGD) sequence of the TGFB latency-associated peptide, which frees TGFB to bind its cellular receptors. However, little is known about the role of integrins in the development of CP. We investigated the effects of small-molecule integrin inhibitors in a mouse model of CP.


METHODS
We induced CP in C57BL/6 female mice by repeated cerulein administration. An active RGD peptidomimetic compound (Center for World Health and Medicine [CWHM]-12) was delivered by continuous infusion, starting 3 days before or 5 days after cerulein administration began. Pancreata were collected and parenchymal atrophy, fibrosis, and activation of PSCs were assessed by histologic, gene, and protein expression analyses. We measured CWHM-12 effects on activation of TGFB in co-culture assays in which rat PSC cells (large T immortalized cells [LTC-14]) activate expression of a TGFB-sensitive promoter in reporter cells.


RESULTS
Pancreatic tissues of mice expressed messenger RNAs encoding subunits of RGD-binding integrins. Cerulein administration increased expression of these integrins, altered pancreatic cell morphology, and induced fibrosis. The integrin inhibitor CWHM-12 decreased acinar cell atrophy and loss, and substantially reduced fibrosis, activation of PSCs, and expression of genes regulated by TGFB. CWHM-12 also reduced established fibrosis in mice and blocked activation of TGFB in cultured cells.


CONCLUSIONS
Based on studies of a mouse model of CP and cultured PSCs, integrins that bind RGD sequences activate PSCs and promote the development of pancreatic fibrogenesis in mice. Small-molecule antagonists of this interaction might be developed for treatment of pancreatic fibrotic diseases.
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University, Saint Louis, Missouri.
Barbara
B
Ulmasov
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University, Saint Louis, Missouri.
Brent A
BA
Neuschwander-Tetri
Department of Pathology, Saint Louis University, Saint Louis, Missouri.
Jinping
J
Lai
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University, Saint Louis, Missouri.
Vladimir
V
Monastyrskiy
Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University, Saint Louis, Missouri.
Trisha
T
Bhat
Center for World Health and Medicine, Saint Louis University, Saint Louis, Missouri.
Matthew P
MP
Yates
Center for World Health and Medicine, Saint Louis University, Saint Louis, Missouri.
Jonathan
J
Oliva
Center for World Health and Medicine, Saint Louis University, Saint Louis, Missouri.
Michael J
MJ
Prinsen
Center for World Health and Medicine, Saint Louis University, Saint Louis, Missouri.
Peter G
PG
Ruminski
Center for World Health and Medicine, Saint Louis University, Saint Louis, Missouri.
David W
DW
Griggs
CP, chronic pancreatitis; CTGF, connective tissue growth factor; CWHM, Center for World Health and Medicine; Col1a1, collagen type I α1; DMEM, Dulbecco's modified Eagle medium; DMSO, dimethyl sulfoxide; ECM, extracellular matrix; FBS, fetal bovine serum; IC50, median inhibitory concentration; Inflammation; LAP, latency-associated peptide; LTC-14, large T immortalized cells; MLEC, mink lung epithelial cell; MMP, matrix metallopeptidase; PBS, phosphate-buffered saline; PCR, polymerase chain reaction; PSC, pancreatic stellate cell; Pancreas; Peptidomimetic; RGD, arginine-glycine-aspartic acid; Signal Transduction; TGFB, transforming growth factor β; mPSC, mouse pancreatic stellate cell; mRNA, messenger RNA; p-SMAD, phosphorylated SMAD; α-SMA, α-smooth muscle actin