Disrupted NOS signaling in lymphatic endothelial cells exposed to chronically increased pulmonary lymph flow

Associated abnormalities of the lymphatic circulation are well described in congenital heart disease. However, their mechanisms remain poorly elucidated. Using a clinically relevant ovine model of a congenital cardiac defect with chronically increased pulmonary blood flow (shunt), we previously demonstrated that exposure to chronically elevated pulmonary lymph flow is associated with: 1) decreased bioavailable nitric oxide (NO) in pulmonary lymph; and 2) attenuated endothelium-dependent relaxation of thoracic duct rings, suggesting disrupted lymphatic endothelial NO signaling in shunt lambs. To further elucidate the mechanisms responsible for this altered NO signaling, primary lymphatic endothelial cells (LECs) were isolated from the efferent lymphatic of the caudal mediastinal node in 4-wk-old control and shunt lambs. We found that shunt LECs ( n = 3) had decreased bioavailable NO and decreased endothelial nitric oxide synthase (eNOS) mRNA and protein expression compared with control LECs ( n = 3). eNOS activity was also low in shunt LECs, but, interestingly, inducible nitric oxide synthase (iNOS) expression and activity were increased in shunt LECs, as were total cellular nitration, including eNOS-specific nitration, and accumulation of reactive oxygen species (ROS). Pharmacological inhibition of iNOS reduced ROS in shunt LECs to levels measured in control LECs. These data support the conclusion that NOS signaling is disrupted in the lymphatic endothelium of lambs exposed to chronically increased pulmonary blood and lymph flow and may contribute to decreased pulmonary lymphatic bioavailable NO.

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Polychlorinated biphenyls alter the expression of endothelial nitric oxide synthase mRNA in human umbilical vein endothelial cells

Human & Experimental Toxicology ◽

10.1177/0960327107072394 ◽

2007 ◽

Vol 26 (10) ◽

pp. 811-816 ◽

Cited By ~ 9

Author(s):

Naoko Omori ◽

Hideki Fukata ◽

Koji Sato ◽

Koji Yamazaki ◽

Keiko Aida-Yasuoka ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Nitric Oxide Synthase ◽

Polychlorinated Biphenyls ◽

Endothelial Nitric Oxide Synthase ◽

Umbilical Vein ◽

Enos Mrna ◽

Umbilical Vein Endothelial Cells ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

Polychlorinated biphenyls (PCBs) are a group of persistent pollutants that are detected in maternal serum and umbilical cord, suggesting that fetal exposure also needs to be considered. The effects of dioxin-like PCB congeners 3,3',4,4'-tetrachlorobiphenyl (PCB77) and 3,3',4,4',5-pentachlorobiphenyl (PCB126) and a non-dioxin-like compound 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) on the expression of endothelial nitric oxide synthase (eNOS), known to maintain blood flow to the fetus, in human umbilical vein endothelial cells (HUVECs) were investigated. The mRNA levels of eNOS, aryl hydrocarbon receptor (AhR) and cytochrome P450 (CYP) 1A1 in cells treated with 5 µM PCBs for 24 hours were analysed by real-time RT-PCR. Cells were also treated with α-naphthoflavone (α NF), an AhR antagonist or ICI 182780, an estrogen receptor (ER) antagonist, one hour prior to PCB exposure, to observe the effects of these receptors on eNOS modulation. Each PCB increased the eNOS mRNA level by 4.5-fold that was markedly inhibited by αNF. ERs were also suspected of altering eNOS levels because ICI 182780 treatment resulted in a decrease in the eNOS level. These results suggest that the eNOS mRNA expression increases due to the action of PCBs related to both AhR and ERs in HUVECs, and that maternal PCB exposure could influence fetal circulation. Human & Experimental Toxicology (2007) 26, 811— 816

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Expression of Endothelial Nitric Oxide Synthase in Human Peritoneal Tissue

Journal of the American Society of Nephrology ◽

10.1681/asn.v11101848 ◽

2000 ◽

Vol 11 (10) ◽

pp. 1848-1856 ◽

Cited By ~ 2

Author(s):

MARÍA M. ARRIERO ◽

JUAN A. RODRÍGUEZ-FEO ◽

ÁNGEL CELDRÁN ◽

LOURDES SÁNCHEZ DE MIGUEL ◽

FERNANDO GONZÁLEZ-FERNÁNDEZ ◽

...

Keyword(s):

Nitric Oxide ◽

Endothelial Cells ◽

Nitric Oxide Synthase ◽

Endothelial Nitric Oxide Synthase ◽

Cytosolic Proteins ◽

Peritoneal Cells ◽

Enos Mrna ◽

Oxide Synthase ◽

Endothelial Nitric Oxide ◽

Enos Protein

Abstract. Changes in the expression of endothelial nitric oxide synthase (eNOS) in the peritoneum could be involved in the peritoneal dysfunction associated with peritoneal inflammation. Demonstrated recently in bovine endothelial cells was the existence of cytosolic proteins that bind to the 3′-untranslated region (3′-UTR) of eNOS mRNA and could be implicated in eNOS mRNA stabilization. The present work demonstrates that eNOS protein is expressed in human endothelial and mesothelial peritoneal cells. Escherichia coli lipopolysaccharide shortened the half-life of eNOS message, reducing eNOS protein expression in peritoneal mesothelial and endothelial cells. Moreover, under basal conditions, human peritoneal samples expressed cytosolic proteins that bind to the 3′-UTR of eNOS mRNA. The cytosolic proteins that directly bind to 3′-UTR were identified as a 60-kD protein. After incubation of human peritoneal samples with lipopolysaccharide, the binding activity of the cytosolic 60-kD protein increased in a time-dependent manner. Studies are now necessary to determine the involvement of this 60-kD protein in the regulation of eNOS expression in peritoneal cells and particularly its involvement in the peritoneal dysfunction associated with inflammatory reactions.

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