IngentaConnect Regulation of bovine corneal endothelial cell cycle by transformi...

Abstract:

. Purpose:

The transforming growth factor-β (TGF-β) family includes three multifunctional proteins, TGF-β1, TGF-β2 and TGF-β3, expressed in ocular tissue, which are involved in regulating cell differentiation, cell proliferation and other cell functions. TGF-β is present in aqueous humour and regulates corneal endothelial cells. This study explores the mechanism by which TGF-β regulates the cell cycle in cultured corneal endothelial cells. Methods:

The expression of specific receptors for the TGF-β family was investigated at the protein level by affinity cross-linking with radio-iodinated TGF-β1 and immunoprecipitation with specific antibodies to TGF-β receptors. Regulation of entry into the S-phase of the cell cycle was determined by 5-bromo-2′ deoxyuridine (BrdU) incorporation into the cells. The signal transduction pathways were investigated using various blocking agents for protein kinase transducers involved in intracytoplasmic signal transduction. Results:

Cultured bovine corneal endothelial cells were confirmed to express TGF-β type 1 and type 2 receptors and endoglin. In the confluent state, TGF-β1 and TGF-β2 stimulated the cells to progress to the S-phase of the cell cycle through platelet-derived growth factor-B (PDGF-B) chain production and protein kinase C. Conclusions:

TGF-β accelerated cell cycle progression from the G0/G1 phase to the S-phase in cultured corneal endothelial cells, under our experimental conditions, through pathways involving protein kinase C. These pathways are related to the cross-talk between TGF-β and other cytokines. The conditions employed in the present experiments may be useful for investigating the complex cross-talk between various cytokines and growth factors.

Keywords: bovine corneal endothelial cell; cell cycle; S-phase; signal transduction; TGF-β

Document Type: Research article

DOI: 10.1034/j.1600-0420.2003.00128.x

Affiliations: 1: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan 2: Department of Ophthalmology, University of Yamagata School of Medicine, Yamagata, Japan

You have access to the full text article on a website external to Ingentaconnect.

Please click here to view this article on InterScience.

You may be required to register and activate access on InterScience before you can obtain the full text. If you have any queries please contact onlinehelp@oxon.blackwellpublishing.com

Regulation of bovine corneal endothelial cell cycle by transforming growth factor-β