Endothelial nitric oxide synthase and caveolin-1 are co-localized in sinusoidal endothelial fenestrae

Authors: Yokomori H.¹; Oda M.²; Ogi M.³; Kamegaya Y.²; Tsukada N.²; Ishii H.²

Source: Liver International, Volume 21, Number 3, June 2001 , pp. 198-206(9)

Publisher: Wiley-Blackwell

Abstract:

Background/Aims: Nitric oxide is synthesized in diverse mammalian tissues by a family of calmodulin-dependent nitric oxide synthases (NOS). Caveolin, the principal structural protein in caveolae, interacts with endothelial NOS leading to enzyme inhibition in a reversible process modulated by Ca⁺⁺-calmodulin. The aim of the present study was to clarify the ultrastructural localization of eNOS and caveolin-1 in hepatic sinusoidal endothelium by an electron immunogold method. Methods: Male Wistar rats were used. Liver tissues and hepatic sinusoidal endothelial cells isolated from rat livers by collagenase infusion were studied. For immunohistochemistry, liver specimens were reacted with anti-eNOS or anti-caveolin-1 antibody. The ultrastructural localization of eNOS or caveolin-1 was identified by electron microscopy using an immunogold post-embedding method. Results: Immunohistochemical studies using liver tissues localized endothelial NOS in hepatic sinusoidal lining cells, portal veins and hepatic arteries; and caveolin-1 in sinusoidal lining cells, bile canaliculi, portal vein and hepatic arteries. Immunogold particles indicating the presence of eNOS and caveolin-1 were demonstrated on the plasma membrane of sinusoidal endothelial fenestrae in liver tissue and also in isolated sinusoidal endothelial cells. Conclusion: Endothelial NOS and caveolin are co-localized on sinusoidal endothelial fenestrae, suggesting that interaction of the two may modulate cellular regulation of NO synthesis.

Keywords: caveolin-1; endothelial nitric oxide; eNOS; immunogold electron microscopy; immunohistochemistry; SEF; sinusoidal endothelial cell; sinusoidal endothelial fenestrae

Language: English

Document Type: Original article

Affiliations: 1: Department of Internal Medicine and 2: Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan 3: Laboratory of Pathology, Kitasato Medical Center Hospital, Saitama and *

Publication date: 2001-06-01

• In this: publication
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• In this Subject: Gastroenterology
• By this author: Yokomori H. ;  Oda M. ;  Ogi M. ;  Kamegaya Y. ;  Tsukada N. ;  Ishii H.

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