N-(methylamino)isobutyric acid inhibits proliferation of CFSC-2C hepatic stellate cells

Research output: Contribution to journalArticle

Abstract

Activation of hepatic stellate cells (HSCs) involves the induction of ECM protein synthesis and rapid cell proliferation. Thus, agents that interfere with either process could potentially mitigate the development of liver disease by reducing the synthesis of proteins associated with fibrosis or by reducing the number of activated HSC. Previously, we described that the non-metabolizable amino acid analog N-(methylamino)isobutyric acid (MeAIB) reduced hepatic collagen content of rats in a model of CCl4-induced liver injury, and in vitro studies using CFSC-2G cells indicated that MeAIB directly reduced collagen synthesis. However, the MeAIB-mediated reduction of hepatic collagen, in vivo, following liver injury was associated with a decrease in hepatic α-smooth muscle actin (α-SMA) which suggested that MeAIB also inhibited the activation of HSCs. Because HSC activation is inseparable from proliferation, the purpose of this study was to examine the effect of MeAIB treatment on the proliferation of HSCs in an in vitro model utilizing CFSC-2G cell cultures. In these studies, MeAIB effectively inhibited the proliferation of CFSC-2G cells by interfering with the progression of the cells through the G1-phase of the cell cycle which delayed entry into S-phase. MeAIB prevented the phosphorylation of p70S6 kinase (p70S6K) at Thr389 and reduced the phosphorylation at Thr421/Ser424. Because p70S6K is required for G 1-cell cycle progression and is known to be regulated by nutrient availability, this correlates well with MeAIB interfering with the proliferation of CFSC-2G HSCs. In addition, the rate of protein synthesis was reduced by MeAIB treatment following mitogenic stimulation, which agrees with a p70S6K-mediated reduction in translation. These data are consistent with MeAIB inhibiting the proliferation of CFSC-2G cells by altering the mitogen activated pathway(s) leading to phosphorylation of p70S6K by a yet to be described mechanism.

Original languageEnglish (US)
Pages (from-to)223-230
Number of pages8
JournalBiochemical Pharmacology
Volume68
Issue number2
DOIs
StatePublished - Jul 15 2004

Fingerprint

Hepatic Stellate Cells
Phosphorylation
Phosphotransferases
Liver
Collagen
Chemical activation
Cells
Cell Cycle
2-(methylamino)isobutyric acid
Military electronic countermeasures
Gastrin-Secreting Cells
Proteins
Wounds and Injuries
Cell proliferation
G1 Phase
S Phase
Mitogens
Cell culture
Nutrients
Smooth Muscle

Keywords

  • ALLN
  • ECM
  • MAPK
  • MeAIB
  • N-(methylamino)isobutyric acid
  • N-acetyl-leu-leu-norleu-al
  • N-boc-ile-glu-(O-t-butyl)-ala-leucinal
  • PSI
  • extracellular matrix
  • mitogen activated protein kinase
  • p70S6 kinase
  • p70S6K
  • α-SMA
  • α-smooth muscle actin

ASJC Scopus subject areas

  • Biochemistry
  • Pharmacology

Cite this

N-(methylamino)isobutyric acid inhibits proliferation of CFSC-2C hepatic stellate cells. / Freeman, T. L.; Thiele, Geoffrey Milton; Klassen, Lynell Warren; Klassen, B. T.; Mailliard, Mark E.

In: Biochemical Pharmacology, Vol. 68, No. 2, 15.07.2004, p. 223-230.

Research output: Contribution to journalArticle

@article{c37c5ea6eb2e435684d8552bb0b47d68,
title = "N-(methylamino)isobutyric acid inhibits proliferation of CFSC-2C hepatic stellate cells",
abstract = "Activation of hepatic stellate cells (HSCs) involves the induction of ECM protein synthesis and rapid cell proliferation. Thus, agents that interfere with either process could potentially mitigate the development of liver disease by reducing the synthesis of proteins associated with fibrosis or by reducing the number of activated HSC. Previously, we described that the non-metabolizable amino acid analog N-(methylamino)isobutyric acid (MeAIB) reduced hepatic collagen content of rats in a model of CCl4-induced liver injury, and in vitro studies using CFSC-2G cells indicated that MeAIB directly reduced collagen synthesis. However, the MeAIB-mediated reduction of hepatic collagen, in vivo, following liver injury was associated with a decrease in hepatic α-smooth muscle actin (α-SMA) which suggested that MeAIB also inhibited the activation of HSCs. Because HSC activation is inseparable from proliferation, the purpose of this study was to examine the effect of MeAIB treatment on the proliferation of HSCs in an in vitro model utilizing CFSC-2G cell cultures. In these studies, MeAIB effectively inhibited the proliferation of CFSC-2G cells by interfering with the progression of the cells through the G1-phase of the cell cycle which delayed entry into S-phase. MeAIB prevented the phosphorylation of p70S6 kinase (p70S6K) at Thr389 and reduced the phosphorylation at Thr421/Ser424. Because p70S6K is required for G 1-cell cycle progression and is known to be regulated by nutrient availability, this correlates well with MeAIB interfering with the proliferation of CFSC-2G HSCs. In addition, the rate of protein synthesis was reduced by MeAIB treatment following mitogenic stimulation, which agrees with a p70S6K-mediated reduction in translation. These data are consistent with MeAIB inhibiting the proliferation of CFSC-2G cells by altering the mitogen activated pathway(s) leading to phosphorylation of p70S6K by a yet to be described mechanism.",
keywords = "ALLN, ECM, MAPK, MeAIB, N-(methylamino)isobutyric acid, N-acetyl-leu-leu-norleu-al, N-boc-ile-glu-(O-t-butyl)-ala-leucinal, PSI, extracellular matrix, mitogen activated protein kinase, p70S6 kinase, p70S6K, α-SMA, α-smooth muscle actin",
author = "Freeman, {T. L.} and Thiele, {Geoffrey Milton} and Klassen, {Lynell Warren} and Klassen, {B. T.} and Mailliard, {Mark E}",
year = "2004",
month = "7",
day = "15",
doi = "10.1016/j.bcp.2004.03.012",
language = "English (US)",
volume = "68",
pages = "223--230",
journal = "Biochemical Pharmacology",
issn = "0006-2952",
publisher = "Elsevier Inc.",
number = "2",

}

TY - JOUR

T1 - N-(methylamino)isobutyric acid inhibits proliferation of CFSC-2C hepatic stellate cells

AU - Freeman, T. L.

AU - Thiele, Geoffrey Milton

AU - Klassen, Lynell Warren

AU - Klassen, B. T.

AU - Mailliard, Mark E

PY - 2004/7/15

Y1 - 2004/7/15

N2 - Activation of hepatic stellate cells (HSCs) involves the induction of ECM protein synthesis and rapid cell proliferation. Thus, agents that interfere with either process could potentially mitigate the development of liver disease by reducing the synthesis of proteins associated with fibrosis or by reducing the number of activated HSC. Previously, we described that the non-metabolizable amino acid analog N-(methylamino)isobutyric acid (MeAIB) reduced hepatic collagen content of rats in a model of CCl4-induced liver injury, and in vitro studies using CFSC-2G cells indicated that MeAIB directly reduced collagen synthesis. However, the MeAIB-mediated reduction of hepatic collagen, in vivo, following liver injury was associated with a decrease in hepatic α-smooth muscle actin (α-SMA) which suggested that MeAIB also inhibited the activation of HSCs. Because HSC activation is inseparable from proliferation, the purpose of this study was to examine the effect of MeAIB treatment on the proliferation of HSCs in an in vitro model utilizing CFSC-2G cell cultures. In these studies, MeAIB effectively inhibited the proliferation of CFSC-2G cells by interfering with the progression of the cells through the G1-phase of the cell cycle which delayed entry into S-phase. MeAIB prevented the phosphorylation of p70S6 kinase (p70S6K) at Thr389 and reduced the phosphorylation at Thr421/Ser424. Because p70S6K is required for G 1-cell cycle progression and is known to be regulated by nutrient availability, this correlates well with MeAIB interfering with the proliferation of CFSC-2G HSCs. In addition, the rate of protein synthesis was reduced by MeAIB treatment following mitogenic stimulation, which agrees with a p70S6K-mediated reduction in translation. These data are consistent with MeAIB inhibiting the proliferation of CFSC-2G cells by altering the mitogen activated pathway(s) leading to phosphorylation of p70S6K by a yet to be described mechanism.

AB - Activation of hepatic stellate cells (HSCs) involves the induction of ECM protein synthesis and rapid cell proliferation. Thus, agents that interfere with either process could potentially mitigate the development of liver disease by reducing the synthesis of proteins associated with fibrosis or by reducing the number of activated HSC. Previously, we described that the non-metabolizable amino acid analog N-(methylamino)isobutyric acid (MeAIB) reduced hepatic collagen content of rats in a model of CCl4-induced liver injury, and in vitro studies using CFSC-2G cells indicated that MeAIB directly reduced collagen synthesis. However, the MeAIB-mediated reduction of hepatic collagen, in vivo, following liver injury was associated with a decrease in hepatic α-smooth muscle actin (α-SMA) which suggested that MeAIB also inhibited the activation of HSCs. Because HSC activation is inseparable from proliferation, the purpose of this study was to examine the effect of MeAIB treatment on the proliferation of HSCs in an in vitro model utilizing CFSC-2G cell cultures. In these studies, MeAIB effectively inhibited the proliferation of CFSC-2G cells by interfering with the progression of the cells through the G1-phase of the cell cycle which delayed entry into S-phase. MeAIB prevented the phosphorylation of p70S6 kinase (p70S6K) at Thr389 and reduced the phosphorylation at Thr421/Ser424. Because p70S6K is required for G 1-cell cycle progression and is known to be regulated by nutrient availability, this correlates well with MeAIB interfering with the proliferation of CFSC-2G HSCs. In addition, the rate of protein synthesis was reduced by MeAIB treatment following mitogenic stimulation, which agrees with a p70S6K-mediated reduction in translation. These data are consistent with MeAIB inhibiting the proliferation of CFSC-2G cells by altering the mitogen activated pathway(s) leading to phosphorylation of p70S6K by a yet to be described mechanism.

KW - ALLN

KW - ECM

KW - MAPK

KW - MeAIB

KW - N-(methylamino)isobutyric acid

KW - N-acetyl-leu-leu-norleu-al

KW - N-boc-ile-glu-(O-t-butyl)-ala-leucinal

KW - PSI

KW - extracellular matrix

KW - mitogen activated protein kinase

KW - p70S6 kinase

KW - p70S6K

KW - α-SMA

KW - α-smooth muscle actin

UR - http://www.scopus.com/inward/record.url?scp=2942602937&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2942602937&partnerID=8YFLogxK

U2 - 10.1016/j.bcp.2004.03.012

DO - 10.1016/j.bcp.2004.03.012

M3 - Article

C2 - 15193994

AN - SCOPUS:2942602937

VL - 68

SP - 223

EP - 230

JO - Biochemical Pharmacology

JF - Biochemical Pharmacology

SN - 0006-2952

IS - 2

ER -