TY - JOUR
T1 - Role of Protein Kinase a Pathway in Epidermal Growth Factor-Induced Liver Cell Repair
AU - Kikuchi, Minako
AU - Ma, Thomas Y.
AU - Tarnawski, Andrzej S.
AU - Shimada, Hiroshi
AU - Sarfeh, I. James
N1 - Funding Information:
From the Departments of Surgery and Medicine (M.K., T.Y.M., A.S.T., and I.J.S.), Department of Veterans Affairs Medical Center, Long Beach, Calif.; University of California, Irvine, Calif.; and the Second Department of Surgery (M.K. and H.S.), Yokohama City University, Yokohama, Japan. Supported by the Medical Research Service of the Veterans Affairs. Presented at the Thirty-Seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, Calif., May 19-22,1996. Reprint requests: I. James Sarfeh, M.D., F.A.C.S., Department of Surgery, Department ofveterans Affairs Medical Center, 5901 E. Seventh St., Long Beach, CA 90822.
PY - 1997
Y1 - 1997
N2 - To gain a better understanding of the mechanisms that control the repair process in the injured liver, the actions of epidermal growth factor (EGF) and protein kinase A (PKA) were studied. Normal rat liver cells (clone 9) were grown to confluence. Standardized excisional wounds were made with a razor blade. The extent of hepatocyte migration into the wound was measured and determined at specific time intervals using a computerized digital analyzing system. Immunostaining of F-actin was performed with a fluorescein-labeled phalloidin. EGF significantly stimulated liver cell migration, whereas specific EGF-neutralizing antibody inhibited the EGF-induced migration. Agents that activate PKA at different stages of the PKA activation pathway, including 3-isobutyl-1-methylxanthine (IBMX), forskolin, and cholera toxin, inhibited EGF-induced migration. EGF triggered formation of actin stress fibers. PKA-activating agents inhibited actin stress fiber formation and stretching of cells at the wound margin. The following conclusions were drawn: (1) In excisional wounds of hepatocyte monolayers, both EGF and PKA exert action on actin microfilaments, which are stretched by EGF and inhibited by PKA; (2) the enhanced repair of wounded hepatocyte monolayers by EGF is blocked by activation of the PKA pathway at various levels; and (3) these actions of EGF and PKA indicate their important regulatory roles in controlling the rate of hepatocyte migration and restitution following the creation of excisional wounds.
AB - To gain a better understanding of the mechanisms that control the repair process in the injured liver, the actions of epidermal growth factor (EGF) and protein kinase A (PKA) were studied. Normal rat liver cells (clone 9) were grown to confluence. Standardized excisional wounds were made with a razor blade. The extent of hepatocyte migration into the wound was measured and determined at specific time intervals using a computerized digital analyzing system. Immunostaining of F-actin was performed with a fluorescein-labeled phalloidin. EGF significantly stimulated liver cell migration, whereas specific EGF-neutralizing antibody inhibited the EGF-induced migration. Agents that activate PKA at different stages of the PKA activation pathway, including 3-isobutyl-1-methylxanthine (IBMX), forskolin, and cholera toxin, inhibited EGF-induced migration. EGF triggered formation of actin stress fibers. PKA-activating agents inhibited actin stress fiber formation and stretching of cells at the wound margin. The following conclusions were drawn: (1) In excisional wounds of hepatocyte monolayers, both EGF and PKA exert action on actin microfilaments, which are stretched by EGF and inhibited by PKA; (2) the enhanced repair of wounded hepatocyte monolayers by EGF is blocked by activation of the PKA pathway at various levels; and (3) these actions of EGF and PKA indicate their important regulatory roles in controlling the rate of hepatocyte migration and restitution following the creation of excisional wounds.
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U2 - 10.1016/S1091-255X(97)80100-X
DO - 10.1016/S1091-255X(97)80100-X
M3 - Article
C2 - 9834339
AN - SCOPUS:0007157555
SN - 1091-255X
VL - 1
SP - 132
EP - 137
JO - Journal of Gastrointestinal Surgery
JF - Journal of Gastrointestinal Surgery
IS - 2
ER -