Loss of c-Met disrupts gene expression program required for G2/M progression during liver regeneration in mice

TY - JOUR

T1 - Loss of c-Met disrupts gene expression program required for G2/M progression during liver regeneration in mice

AU - Factor, Valentina M

AU - Seo, Daekwan

AU - Ishikawa, Tsuyoshi

AU - Kaposi-Novak, Pal

AU - Marquardt, Jens U

AU - Andersen, Jesper Bøje

AU - Conner, Elizabeth A

AU - Thorgeirsson, Snorri S

PY - 2010

Y1 - 2010

N2 - Background: Previous work has established that HGF/c-Met signaling plays a pivotal role in regulating the onset of S phase following partial hepatectomy (PH). In this study, we used Metfl/fl;Alb-Cre+/- conditional knockout mice to determine the effects of c-Met dysfunction in hepatocytes on kinetics of liver regeneration. Methodology/Principal Finding: The priming events appeared to be intact in Metfl/fl;Alb-Cre+/- livers. Up-regulation of stress response (MAFK, IKBZ, SOCS3) and early growth response (c-Myc, c-Jun, c-Fos, DUSP1 and 6) genes as assessed by RT-qPCR and/ or microarray profiling was unchanged. This was consistent with an early induction of MAPK/Erk and STAT3. However, after a successful completion of the first round of DNA replication, c-Met deficient hepatocytes were blocked in early/mid G2 phase as shown by staining with phosphorylated form of histone H3. Furthermore, loss of c-Met in hepatocytes diminished the subsequent G1/S progression and delayed liver recovery after partial hepatectomy. Upstream signaling pathways involved in the blockage of G2/M transition included lack of persistent Erk1/2 activation and inability to up-regulate the levels of Cdk1, Plk1, Aurora A and B, and Mad2 along with a defective histone 3 phosphorylation and lack of chromatin condensation. Continuous supplementation with EGF in vitro increased proliferation of Metfl/fl;Alb-Cre+/- primary hepatocytes and partially restored expression levels of mitotic cell cycle regulators albeit to a lesser degree as compared to control cultures. Conclusion/Significance: In conclusion, our results assign a novel non-redundant function for HGF/c-Met signaling in regulation of G2/M gene expression program via maintaining a persistent Erk1/2 activation throughout liver regeneration.

AB - Background: Previous work has established that HGF/c-Met signaling plays a pivotal role in regulating the onset of S phase following partial hepatectomy (PH). In this study, we used Metfl/fl;Alb-Cre+/- conditional knockout mice to determine the effects of c-Met dysfunction in hepatocytes on kinetics of liver regeneration. Methodology/Principal Finding: The priming events appeared to be intact in Metfl/fl;Alb-Cre+/- livers. Up-regulation of stress response (MAFK, IKBZ, SOCS3) and early growth response (c-Myc, c-Jun, c-Fos, DUSP1 and 6) genes as assessed by RT-qPCR and/ or microarray profiling was unchanged. This was consistent with an early induction of MAPK/Erk and STAT3. However, after a successful completion of the first round of DNA replication, c-Met deficient hepatocytes were blocked in early/mid G2 phase as shown by staining with phosphorylated form of histone H3. Furthermore, loss of c-Met in hepatocytes diminished the subsequent G1/S progression and delayed liver recovery after partial hepatectomy. Upstream signaling pathways involved in the blockage of G2/M transition included lack of persistent Erk1/2 activation and inability to up-regulate the levels of Cdk1, Plk1, Aurora A and B, and Mad2 along with a defective histone 3 phosphorylation and lack of chromatin condensation. Continuous supplementation with EGF in vitro increased proliferation of Metfl/fl;Alb-Cre+/- primary hepatocytes and partially restored expression levels of mitotic cell cycle regulators albeit to a lesser degree as compared to control cultures. Conclusion/Significance: In conclusion, our results assign a novel non-redundant function for HGF/c-Met signaling in regulation of G2/M gene expression program via maintaining a persistent Erk1/2 activation throughout liver regeneration.

KW - Animals

KW - Cell Division

KW - Female

KW - G2 Phase

KW - Gene Expression Regulation

KW - Hepatocytes

KW - Liver

KW - Liver Regeneration

KW - MAP Kinase Signaling System

KW - Male

KW - Mice

KW - Mice, Knockout

KW - Proto-Oncogene Proteins c-met

KW - Up-Regulation

U2 - 10.1371/journal.pone.0012739

DO - 10.1371/journal.pone.0012739

M3 - Journal article

C2 - 20862286

SN - 1932-6203

VL - 5

JO - PLoS Computational Biology

JF - PLoS Computational Biology

IS - 9

ER -