Endothelin-1 stimulates contraction and migration of rat pancreatic stellate cells

Activated pancreatic stellate cells (PSCs) are implicated in the pathogenesis of pancreatic fibrosis and inflammation. Endothelin-1 (ET-1), which acts through G-protein coupled ET(A) and ET(B) receptors, has several biological activities. We here examined the ability of ET-1 to affect the cell functions of PSCs and the underlying molecular mechanisms.

PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase, and cells between passages two and five were used. Expression of ET-1 and ET receptors was assessed by reverse transcription-PCR and immunostaining. Phosphorylation of myosin regulatory light chain (MLC), extracellular-signal regulated kinase (ERK), and Akt was examined by Western blotting. Contraction of PSCs was assessed on hydrated collagen lattices. Cell migration was examined using modified Boyden chambers. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxyuridine.

Culture-activated PSCs expressed ET(A) and ET(B) receptors, and ET-1. ET-1 induced phosphorylation of MLC and ERK, but not Akt. ET-1 induced contraction and migration, but did not alter proliferation of PSCs. ET-1-induced contraction was inhibited by an ET(A) receptor antagonist BQ-123 and an ET(B) receptor antagonist BQ-788, whereas migration was inhibited by BQ-788 but not by BQ-123. A Rho kinase inhibitor Y-27632 abolished both contraction and migration.

ET-1 induced contraction and migration of PSCs through ET receptors and activation of Rho-Rho kinase. ET(A) and ET(B) receptors play different roles in the regulation of these cellular functions in response to ET-1.