Charge, Sophie B. P., and Michael A. Rudnicki. Cellular and Molecular Regulation of Muscle Regeneration. Physiol Rev 84: 209–238, 2004; 10.1152/physrev.00019.2003.—Under normal circumstances, mamma...

Cellular and Molecular Regulation of Muscle Regeneration

Hepatocyte growth factor (HGF) is the most potent mitogen for mature parenchymal hepatocytes in primary culture, and seems to be a hepatotrophic factor that acts as a trigger for liver regeneration after partial hepatectomy and liver injury. The partial purification and characterization of HGF have been reported. We have demonstrated that pure HGF from rat platelets is a new growth factor effective at concentrations as low as 1 ng ml-1. The effects of HGF and epidermal growth factor (EGF) are additive. The activity of HGF is not species-specific, although it does not stimulate growth in Swiss 3T3 fibroblasts. HGF has a relative molecular mass (Mr) of 82,000 and is a heterodimer composed of a large alpha-subunit of Mr 69,000 and a small beta-subunit of Mr 34,000. Here we report the amino-acid sequence of human HGF determined by complementary DNA cloning and the expression of biologically active human HGF from COS-1 cells transfected with cloned cDNA. The nucleotide sequence of the human HGF cDNA reveals that both alpha- and beta-chains are contained in a single open reading frame coding for a pre-pro precursor protein of 728 amino acids.

Molecular cloning and expression of human hepatocyte growth factor

Hepatocyte Growth Factor (HGF, also known as Scatter Factor) is a powerful mitogen or motility factor in different cells, acting through the tyrosine kinase receptor encoded by the MET protooncogene Endothelial cells express the MET gene and expose at the cell surface the mature protein (p190MET) made of a 50 kD (alpha) subunit disulfide linked to a 145-kD (beta) subunit HGF binding to endothelial cells identifies two sites with different affinities The higher affinity binding site (Kd = 035 nM) corresponds to the p190MET receptor Sub-nanomolar concentrations of HGF, but not of a recombinant inactive precursor, stimulate the receptor kinase activity, cell proliferation and motility HGF induces repairs of a wound in endothelial cell monolayer HGF stimulates the scatter of endothelial cells grown on three-dimensional collagen gels, inducing an elongated phenotype In the rabbit cornea, highly purified HGF promotes neovascularization at sub-nanomolar concentrations HGF lacks activities related to hemostasis-thrombosis, inflammation and endothelial cells accessory functions These data show that HGF is an in vivo potent angiogenic factor and in vitro induces endothelial cells to proliferate and migrate

https://rupress.org/jcb/article-pdf/119/3/629/1063657/629.pdf

Hepatocyte growth factor is a potent angiogenic factor which stimulates endothelial cell motility and growth

Hypoxia promotes invasive growth by transcriptional activation of the met protooncogene.

Signaling pathways that mediate the normal functions of growth factors are commonly subverted in cancer. Oncogenes identified by a variety of approaches have been shown to function at critical steps in mitogenic signaling. Progression through the cell cycle requires the coordinated actions of members of two complementary classes of growth factors, and oncogenes appear to replace the actions of one set of these growth factors. Growth factors can also influence normal cell differentiation, and constitutive activation of growth-promoting pathways in cancer cells can modulate the cell phenotype as well. Paracrine actions of growth factors and cytokines may also influence the stepwise series of genetic events that lead to malignancy. New approaches for cancer therapy are being developed that intervene at various steps in growth factor signaling pathways.

https://science.sciencemag.org/content/sci/254/5035/1146.full.pdf

Growth factors and cancer

Partial purification and characterization of hepatocyte growth factor from serum of hepatectomized rats.

A growth factor (HGF) stimulating DNA synthesis of adult rat hepatocytes in primary culture was found in rat platelets. HGF was purified from rat platelets to homogeneity by a three-step procedure: stimulation of its release from platelets by thrombin, cation-exchanger fast protein liquid chromatography on a Mono S column, and heparin-Sepharose chromatography. HGF was clearly distinguishable from the platelet-derived growth factor (PDGF) by fast protein liquid chromatography. HGF was a heat- and acid-labile cationic protein that was inactivated by reduction with dithiothreitol. Its molecular mass was estimated to be 27 kDa by NaDodSO4/PAGE and its amino acid composition was very different from that of PDGF. The purified HGF stimulated DNA synthesis in adult rat hepatocytes at 2 ng/ml and was maximally effective at 20 ng/ml; its effect was additive or synergistic with those of insulin and EGF, depending on their combinations. HGF did not stimulate DNA synthesis of Swiss 3T3 cells, while PDGF did not stimulate that of hepatocytes. Thus, HGF showed clearly different cell specificity from PDGF in its growth-promoting activities. These findings indicate that HGF is a growth factor in platelets for mature hepatocytes.

https://www.pnas.org/content/pnas/83/17/6489.full.pdf

Purification and characterization of a growth factor from rat platelets for mature parenchymal hepatocytes in primary cultures

L-Proline is an essential amino acid for hepatocyte growth in culture

Reciprocal modulation of growth and liver functions of mature rat hepatocytes in primary culture by an extract of hepatic plasma membranes.

A cell-surface modulator with the ability to mimic the reciprocal effects of cell density on cell growth and liver-specific functions of mature rat hepatocytes in primary culture (Nakamura, T., Yoshimoto, K., Nakayama, Y., Tomita, Y., and Ichihara, A. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 7229-7233) was solubilized with 4% octyl glucoside and 4 M guanidine HCl from plasma membranes purified from adult rat liver. The membrane-free modulator showed activities for inhibition of DNA synthesis stimulated by insulin with epidermal growth factor and stimulation of tyrosine aminotransferase induction by dexamethasone. The apparent Mr of the factor was estimated as 670,000 by gel filtration on a Sephacryl S-400 column equilibrated with 0.5% octyl glucoside and 4 M guanidine HCl. The modulator was heat-labile and sensitive to trypsin. These results suggest that the reciprocal regulations of cell growth and hepatocyte-specific functions are mediated via cell to cell contact by a cell-surface modulator(s) that is an integral membrane protein.

Toshikazu Nakamura

Papers

Partial purification and characterization of hepatocyte growth factor from serum of hepatectomized rats.

Purification and characterization of a growth factor from rat platelets for mature parenchymal hepatocytes in primary cultures

L-Proline is an essential amino acid for hepatocyte growth in culture

Reciprocal modulation of growth and liver functions of mature rat hepatocytes in primary culture by an extract of hepatic plasma membranes.

Reciprocal Modulation of Growth and Liver Functions of Mature Rat Hepatocytes in Primary Culture by an Extract of Hepatic