Regulation of Endothelial Constitutive Nitric Oxide Synthase Gene Expression in Endothelial Cells and In Vivo

Constitutively produced nitric oxide released by endothelial cells has been shown to act as an endogenous agent which inhibits the rolling and adhesion of leucocytes in the microcirculation. However, during various types of inflammation, expression of the inducible form of nitric oxide synthase (iNOS) can dramatically increase the amount of nitric oxide present in tissues. Furthermore, as iNOS can be expressed by a wide variety of cell types, the distribution of nitric oxide is likely to be altered relative to that in unstimulated tissue. Under these conditions, it is less well understood whether iNOS-derived nitric oxide retains the anti-adhesive capabilities of constitutively produced nitric oxide. This review summarizes work done to examine this issue. Three main approaches have been used. In vitro studies have examined the role of iNOS in adhesive interactions between stimulated endothelial cells and leucocytes, providing evidence of an anti-adhesive effect of iNOS. In addition, the role of iNOS has been examined in vivo in animal models of inflammation using pharmacological iNOS inhibitors. These experiments were extended by the advent of the iNOS-deficient (iNOS-/-) mouse. Intravital microscopy studies of these mice have indicated that, under conditions of low-dose endotoxaemia, iNOS-derived nitric oxide can inhibit leucocyte rolling and adhesion. The potential mechanisms for these effects are discussed. In contrast, several other studies have observed either no effect or an enhancing effect of iNOS on inflammatory leucocyte recruitment. Taken together, these studies suggest that the importance of iNOS in modulating leucocyte recruitment can vary according to the type of inflammatory response.

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Modulation of constitutive nitric oxide synthase, bcl-2 and Fas expression in cultured human coronary endothelial cells exposed to anoxia–reoxygenation and angiotensin II: role of AT1 receptor activation

Cardiovascular Research ◽

10.1016/s0008-6363(98)00196-5 ◽

1999 ◽

Vol 41 (1) ◽

pp. 109-115 ◽

Cited By ~ 39

Author(s):

D Li

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Angiotensin Ii ◽

Nitric Oxide Synthase ◽

Receptor Activation ◽

At1 Receptor ◽

Coronary Endothelial Cells ◽

Constitutive Nitric Oxide Synthase ◽

Oxide Synthase

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Endothelin and nitric oxide synthase in lymphatic endothelial cells: Immunolocalization in vivo and in vitro

The Anatomical Record ◽

10.1002/(sici)1097-0185(199708)248:4<490::aid-ar2>3.0.co;2-q ◽

1997 ◽

Vol 248 (4) ◽

pp. 490-497 ◽

Cited By ~ 27

Author(s):

Carla Marchetti ◽

Andrea Casasco ◽

Amalia Di Nucci ◽

Marcella Reguzzoni ◽

Simone Rosso ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Nitric Oxide Synthase ◽

Lymphatic Endothelial Cells ◽

Oxide Synthase

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Identification of Golgi-localized acyl transferases that palmitoylate and regulate endothelial nitric oxide synthase

The Journal of Cell Biology ◽

10.1083/jcb.200601051 ◽

2006 ◽

Vol 174 (3) ◽

pp. 369-377 ◽

Cited By ~ 116

Author(s):

Carlos Fernández-Hernando ◽

Masaki Fukata ◽

Pascal N. Bernatchez ◽

Yuko Fukata ◽

Michelle I. Lin ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Nitric Oxide Synthase ◽

Endothelial Nitric Oxide Synthase ◽

Cdna Clones ◽

No Production ◽

Human Endothelial Cells ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

Lipid modifications mediate the subcellular localization and biological activity of many proteins, including endothelial nitric oxide synthase (eNOS). This enzyme resides on the cytoplasmic aspect of the Golgi apparatus and in caveolae and is dually acylated by both N-myristoylation and S-palmitoylation. Palmitoylation-deficient mutants of eNOS release less nitric oxide (NO). We identify enzymes that palmitoylate eNOS in vivo. Transfection of human embryonic kidney 293 cells with the complementary DNA (cDNA) for eNOS and 23 cDNA clones encoding the Asp-His-His-Cys motif (DHHC) palmitoyl transferase family members showed that five clones (2, 3, 7, 8, and 21) enhanced incorporation of [3H]-palmitate into eNOS. Human endothelial cells express all five of these enzymes, which colocalize with eNOS in the Golgi and plasma membrane and interact with eNOS. Importantly, inhibition of DHHC-21 palmitoyl transferase, but not DHHC-3, in human endothelial cells reduces eNOS palmitoylation, eNOS targeting, and stimulated NO production. Collectively, our data describe five new Golgi-targeted DHHC enzymes in human endothelial cells and suggest a regulatory role of DHHC-21 in governing eNOS localization and function.

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