Cell and molecular regulation of endothelin-1 production during hepatic wound healing.
During hepatic wound healing, activation of key effectors of the wounding response known as stellate cells leads to a multitude of pathological processes, including increased production of endothelin-1 (ET-1). This latter process has been linked to enhanced expression of endothelin-converting enzyme-1 (ECE-1, the enzyme that converts precursor ET-1 to the mature peptide) in activated stellate cells. Herein, we demonstrate up-regulation of 56- and 62-kDa ECE-1 3'-untranslated region (UTR) mRNA binding proteins in stellate cells after liver injury and stellate cell activation. Binding of these proteins was localized to a CC-rich region in the proximal ECE-1 3' UTR base pairs (the 56-kDa protein) and to a region between 60 and 193 base pairs in the ECE-1 3' UTR mRNA (62 kDa). A functional role for the 3' UTR mRNA/protein interaction was established in a series of reporter assays. Additionally, transforming growth factor-beta1, a cytokine integral to wound healing, stimulated ET-1 production. This effect was due to ECE-1 mRNA stabilization and increased ECE-1 expression in stellate cells, which in turn was a result of de novo synthesis of the identified 56- and 62-kDa ECE-1 3' UTR mRNA binding proteins. These data indicate that liver injury and the hepatic wound healing response lead to ECE-1 mRNA stabilization in stellate cells via binding of 56- and 62-kDa proteins, which in turn are regulated by transforming growth factor-beta. The possibility that the same or similar regulatory events are present in other forms of wound healing is raised.
Shao
Rong
R
Duke University Liver Center, Durham, North Carolina 27710, USA.
Shi
Zengdun
Z
Gotwals
Philip J
PJ
Koteliansky
Victor E
VE
George
Jacob
J
Rockey
Don C
DC
D020413:3' Untranslated Regions; D016282:Aspartic Acid Endopeptidases / Q000096:biosynthesis / Q000235:genetics; D001665:Binding Sites; D019332:Endothelin-1 / Q000378:metabolism*; D000072396:Endothelin-Converting Enzymes; D008099:Liver / Q000293:injuries* / Q000378:metabolism; D008666:Metalloendopeptidases; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology*
D020413:3' Untranslated Regions; D019332:Endothelin-1; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes