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Mechanisms of hepatocyte growth factor-induced retinal endothelial cell migration and growth.
Invest Ophthalmol Vis Sci. 2000 Jun; 41(7):1885-93.IO

Abstract

PURPOSE

Hepatocyte growth factor (HGF), also called scatter factor, stimulates growth and motility in nonocular endothelial cells and smooth muscle cells through its receptor c-Met. Recent reports suggest that HGF is increased in the serum and vitreous of patients with proliferative diabetic retinopathy and that smooth muscle cells and retinal pigment epithelial cells secrete HGF in the eye. However, little is known about HGF's action in the retina. In this study, the activity, expression, and signaling pathways of HGF were investigated in bovine retinal microvascular endothelial cells (BRECs).

METHODS

Mitogenic and motogeneic effects of HGF on BRECs were examined using cell counts, thymidine uptake, and migration assays. MAP kinase (MAPK) phosphorylation was examined by Western blot analysis. Protein kinase C (PKC), MAPK, and PI3 kinase involvement were evaluated using selective inhibitors and activity assays. Expression of HGF and c-Met was evaluated by reverse transcription-polymerase chain reaction.

RESULTS

HGF and c-Met were both expressed in BRECs. HGF stimulated BREC growth in a time- and dose-dependent manner, observed at HGF concentrations of 5 ng/ml or more and maximal (410%) at 100 ng/ml (P < 0.001). HGF increased BREC migration in a dose-dependent manner with a maximal 3.4-fold increase at 50 ng/ml after 5 hours. HGF induced time- and dose-dependent MAPK phosphorylation, initially evident at 5 minutes (P < 0.001) or 5 ng/ml (P < 0.050) and maximal after 15 minutes (>80-fold, P < 0.001) or 50 ng/ml (>20-fold, P < 0.001), respectively. MAPK phosphorylation was maintained for more than 2 hours. This response was inhibited 31% by 0.1 microm wortmannin and 76% by 30 microm LY294002, another PI3 kinase inhibitor. The non-isoform-selective PKC inhibitor GFX inhibited HGF-induced MAPK phosphorylation by only 15% at 5 microm. Combined PKC and PI3 kinase inhibition was additive (P < 0.05). Cell migration was inhibited 30% by wortmannin (P < 0.01) and 32% by GFX (P < 0.05), and again the effect was additive (P < 0.001). HGF-induced BREC growth was suppressed by PI3 kinase, PKC, or MAPK inhibition (all P < 0.01). HGF (50 ng/ml) stimulated PI3 kinase activity 347% (P < 0.001) and PKC activity 37% (P < 0.05). HGF-induced MAPK phosphorylation and mitogenesis were not inhibited by vascular endothelial growth factor (VEGF)-neutralizing antibody.

CONCLUSIONS

HGF and its receptor are expressed in BREC, and HGF stimulates both BREC growth and migration at concentrations observed in the human eye with diabetic retinopathy. HGF signaling appears to involve activation of both PKC and PI3 kinase, inducing MAPK phosphorylation that is critical for migration and growth. However, VEGF does not appear to mediate these initial HGF effects. These results indicate that HGF could have a significant role in mediating retinal endothelial cell proliferation and migration in diabetic retinopathy, and they begin to elucidate the signal transduction pathway by which this action may occur.

Authors+Show Affiliations

Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10845613

Citation

Cai, W, et al. "Mechanisms of Hepatocyte Growth Factor-induced Retinal Endothelial Cell Migration and Growth." Investigative Ophthalmology & Visual Science, vol. 41, no. 7, 2000, pp. 1885-93.
Cai W, Rook SL, Jiang ZY, et al. Mechanisms of hepatocyte growth factor-induced retinal endothelial cell migration and growth. Invest Ophthalmol Vis Sci. 2000;41(7):1885-93.
Cai, W., Rook, S. L., Jiang, Z. Y., Takahara, N., & Aiello, L. P. (2000). Mechanisms of hepatocyte growth factor-induced retinal endothelial cell migration and growth. Investigative Ophthalmology & Visual Science, 41(7), 1885-93.
Cai W, et al. Mechanisms of Hepatocyte Growth Factor-induced Retinal Endothelial Cell Migration and Growth. Invest Ophthalmol Vis Sci. 2000;41(7):1885-93. PubMed PMID: 10845613.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mechanisms of hepatocyte growth factor-induced retinal endothelial cell migration and growth. AU - Cai,W, AU - Rook,S L, AU - Jiang,Z Y, AU - Takahara,N, AU - Aiello,L P, PY - 2000/6/14/pubmed PY - 2000/6/17/medline PY - 2000/6/14/entrez SP - 1885 EP - 93 JF - Investigative ophthalmology & visual science JO - Invest. Ophthalmol. Vis. Sci. VL - 41 IS - 7 N2 - PURPOSE: Hepatocyte growth factor (HGF), also called scatter factor, stimulates growth and motility in nonocular endothelial cells and smooth muscle cells through its receptor c-Met. Recent reports suggest that HGF is increased in the serum and vitreous of patients with proliferative diabetic retinopathy and that smooth muscle cells and retinal pigment epithelial cells secrete HGF in the eye. However, little is known about HGF's action in the retina. In this study, the activity, expression, and signaling pathways of HGF were investigated in bovine retinal microvascular endothelial cells (BRECs). METHODS: Mitogenic and motogeneic effects of HGF on BRECs were examined using cell counts, thymidine uptake, and migration assays. MAP kinase (MAPK) phosphorylation was examined by Western blot analysis. Protein kinase C (PKC), MAPK, and PI3 kinase involvement were evaluated using selective inhibitors and activity assays. Expression of HGF and c-Met was evaluated by reverse transcription-polymerase chain reaction. RESULTS: HGF and c-Met were both expressed in BRECs. HGF stimulated BREC growth in a time- and dose-dependent manner, observed at HGF concentrations of 5 ng/ml or more and maximal (410%) at 100 ng/ml (P < 0.001). HGF increased BREC migration in a dose-dependent manner with a maximal 3.4-fold increase at 50 ng/ml after 5 hours. HGF induced time- and dose-dependent MAPK phosphorylation, initially evident at 5 minutes (P < 0.001) or 5 ng/ml (P < 0.050) and maximal after 15 minutes (>80-fold, P < 0.001) or 50 ng/ml (>20-fold, P < 0.001), respectively. MAPK phosphorylation was maintained for more than 2 hours. This response was inhibited 31% by 0.1 microm wortmannin and 76% by 30 microm LY294002, another PI3 kinase inhibitor. The non-isoform-selective PKC inhibitor GFX inhibited HGF-induced MAPK phosphorylation by only 15% at 5 microm. Combined PKC and PI3 kinase inhibition was additive (P < 0.05). Cell migration was inhibited 30% by wortmannin (P < 0.01) and 32% by GFX (P < 0.05), and again the effect was additive (P < 0.001). HGF-induced BREC growth was suppressed by PI3 kinase, PKC, or MAPK inhibition (all P < 0.01). HGF (50 ng/ml) stimulated PI3 kinase activity 347% (P < 0.001) and PKC activity 37% (P < 0.05). HGF-induced MAPK phosphorylation and mitogenesis were not inhibited by vascular endothelial growth factor (VEGF)-neutralizing antibody. CONCLUSIONS: HGF and its receptor are expressed in BREC, and HGF stimulates both BREC growth and migration at concentrations observed in the human eye with diabetic retinopathy. HGF signaling appears to involve activation of both PKC and PI3 kinase, inducing MAPK phosphorylation that is critical for migration and growth. However, VEGF does not appear to mediate these initial HGF effects. These results indicate that HGF could have a significant role in mediating retinal endothelial cell proliferation and migration in diabetic retinopathy, and they begin to elucidate the signal transduction pathway by which this action may occur. SN - 0146-0404 UR - https://www.unboundmedicine.com/medline/citation/10845613/Mechanisms_of_hepatocyte_growth_factor_induced_retinal_endothelial_cell_migration_and_growth_ L2 - http://iovs.arvojournals.org/article.aspx?volume=41&amp;page=1885 DB - PRIME DP - Unbound Medicine ER -