scholarly journals Reduction of electrical coupling between microvascular endothelial cells by NO depends on connexin37

2009 ◽  
Vol 297 (1) ◽  
pp. H93-H101 ◽  
Author(s):  
Rebecca L. McKinnon ◽  
Michael L. Bolon ◽  
Hong-Xing Wang ◽  
Scott Swarbreck ◽  
Gerald M. Kidder ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Electrical Coupling ◽  
Electrical Current ◽  
Microvascular Endothelial Cells ◽  
No Production ◽  
No Donor ◽  
Junction Protein ◽  
Arteriolar Wall ◽  
Microvascular Endothelial ◽  
In Cells

We have previously shown that increased nitric oxide (NO) production in sepsis impairs arteriolar-conducted vasoconstriction cGMP independently and that the gap junction protein connexin (Cx) 37 is required for this conducted response. In the present study, we hypothesized that NO impairs interendothelial electrical coupling in sepsis by targeting Cx37. We examined the effect of exogenous NO on coupling in monolayers of cultured microvascular endothelial cells derived from the hindlimb skeletal muscle of wild-type (WT), Cx37 null, Cx40 null, and Cx43G60S (nonfunctional mutant) mice. To assess coupling, we measured the spread of electrical current injected in the monolayer and calculated the monolayer intercellular resistance (inverse measure of coupling). The NO donor 2,2′-(hydroxynitrosohydrazino) bis-ethanamine (DETA) rapidly and reversibly reduced coupling in cells from WT mice, cGMP independently. NO scavenger HbO2 did not affect baseline coupling, but it eliminated DETA-induced reduction in coupling. Reduced coupling in response to DETA was also seen in cells from Cx40 null and Cx43G60S mice, but not in cells from Cx37 null mice. DETA did not alter the expression of Cx37, Cx40, and Cx43 in WT cells analyzed by immunoblotting and immunofluorescence. Furthermore, neither the peroxynitrite scavenger 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron (III), superoxide scavenger Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, nor preloading of WT cells with the antioxidant ascorbate affected this reduction. We conclude that NO-induced reduction of electrical coupling between microvascular endothelial cells depends on Cx37 and propose that NO in sepsis impairs arteriolar-conducted vasoconstriction by targeting Cx37 within the arteriolar wall.

Stimulation of Tetrahydrobiopterin Synthesis by 17β-Estradiol in Brain Microvascular Endothelial Cells

Pteridines ◽  
2000 ◽  
Vol 11 (4) ◽  
pp. 129-132
Author(s):  
Kazuhiro Shiota ◽  
Masakazu Ishii ◽  
Toshinori Yamamoto ◽  
Shunichi Shimizu ◽  
Yuji Kiuchi
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Vascular Endothelial Cells ◽  
Mrna Level ◽  
Microvascular Endothelial Cells ◽  
No Production ◽  
Brain Microvascular Endothelial Cells ◽  
Protective Effects ◽  
17Β Estradiol ◽  
Microvascular Endothelial

Abstract The purpose of this study was to examine whether 17β-estradiol stimulates the synthesis of tetrahydrobiopterin : BH4), which is one of the cofactors of nitric oxide (NO) synthase, in mouse brain microvascular endothelial cells. Addition of 17()-estradiol to endothelial cells time- and concentration-dependently increased intracellular BH4 level. 17β-Estradiol also stimulated the mRNA level of GTP-cyclohydrolase I (GTPCH), which is a rate-limiting enzyme of the de novo BH4 synthetic pathway. In addition, the 17β-estradiol-induced expression of GTPCH mRNA was strongly attenuated by treatment with an inhibitor of 17β-estradiol receptor 4-hydroxy-tamoxlfen. These results suggest that 17β-estradiol stimulates BH4 synthesis through the induction of GTPCH by tamoxifensensitive receptor in vascular endothelial cells. The 17β-estradiol-induced increase in BH4 level might be implicated in not only NO production, but also protective effects of 17β-estradiol against ischemic brain damage and atherosclerosis, since BH4 is an intracellular antioxidant.

scholarly journals iNOS expression in human intestinal microvascular endothelial cells inhibits leukocyte adhesion

1998 ◽  
Vol 275 (3) ◽  
pp. G592-G603 ◽  
Author(s):  
David G. Binion ◽  
Sidong Fu ◽  
Kalathur S. Ramanujam ◽  
Yuh Cherng Chai ◽  
Raed A. Dweik ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Intestinal Inflammation ◽  
Leukocyte Adhesion ◽  
Primary Cultures ◽  
Inos Expression ◽  
Microvascular Endothelial Cells ◽  
No Production ◽  
Nos Inhibitors ◽  
Microvascular Endothelial

Increased nitric oxide (NO) production by inducible nitric oxide synthase (iNOS) has been associated with intestinal inflammation, including human inflammatory bowel disease. However, NO can downregulate endothelial activation and leukocyte adhesion, critical steps in the inflammatory response. Using primary cultures of human intestinal microvascular endothelial cells (HIMEC), we determined the role of NO in the regulation of HIMEC activation and interaction with leukocytes. Both nonselective ( N G-monomethyl-l-arginine) and specific ( N-iminoethyl-l-lysine) competitive inhibitors of iNOS significantly increased binding of leukocytes by HIMEC activated with cytokines and lipopolysaccharide. Increased adhesion was reversible with the NOS substratel-arginine and was not observed in human umbilical vein endothelial cells (HUVEC). Activation of HIMEC significantly upregulated HIMEC iNOS expression and NO production. NOS inhibitors did not augment cell adhesion molecule levels in activated HIMEC but did result in sustained increases in intracellular reactive oxygen species. In addition, antioxidant compounds reversed the effect of NOS inhibitors on HIMEC-leukocyte interaction. Taken together, these data suggest that after HIMEC activation, iNOS-derived NO is an endogenous antioxidant, downregulating leukocyte binding and potentially downregulating intestinal inflammation.

Carboxypeptidase-mediated enhancement of nitric oxide production in rat lungs and microvascular endothelial cells

2004 ◽  
Vol 287 (1) ◽  
pp. L35-L45 ◽  
Author(s):  
Vaishali Hadkar ◽  
Sakonwun Sangsree ◽  
Stephen M. Vogel ◽  
Viktor Brovkovych ◽  
Randal A. Skidgel
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Hplc Analysis ◽  
Microvascular Endothelial Cells ◽  
No Production ◽  
Inflammatory Conditions ◽  
Rat Lungs ◽  
Inos Inhibitor ◽  
Ifn Γ ◽  
Microvascular Endothelial

Membrane-bound regulatory carboxypeptidases cleave only COOH-terminal basic residues from peptides and proteins. To investigate whether carboxypeptidase-generated arginine can increase nitric oxide (NO) synthesis we perfused rat lungs from animals challenged with LPS or used rat lung microvascular endothelial cells (RLMVEC) stimulated with LPS and IFN-γ, conditions that induced inducible NO synthase (iNOS) expression. Addition of carboxypeptidase substrate furylacryloyl-Ala-Arg (Fa-A-R) or Arg to the lung perfusate increased NO production two- to threefold. The carboxypeptidase inhibitor 2-mercaptomethyl-3-guanidinoethylthiopropanoic acid (MGTA) blocked the effect of Fa-A-R but not free Arg. Lysine, an Arg transport inhibitor, blocked the increase in NO stimulated by Fa-A-R. HPLC analysis showed that Fa-A-R hydrolysis was blocked by MGTA but not lysine. In cytokine-treated RLMVEC, Fa-A-R also stimulated NO production inhibited by MGTA or lysine. Membrane fractions from rat lungs or RLMVEC contained carboxypeptidase M-like activity at neutral pH that increased twofold in RLMVEC treated with LPS + IFN-γ. The kinetics of NO production in RLMVEC was measured with a porphyrinic microsensor. Addition of 1 mM Arg or Fa-A-R to cells preincubated in Arg-free medium resulted in a slowly rising, prolonged (>20 min) NO output. NO production stimulated by Fa-A-R was blocked by MGTA or iNOS inhibitor 1400W. HPLC analysis of Fa-A-R hydrolysis revealed only 3.7 μM Arg was released over 20 min. Thus NO production in RLMVEC is stimulated more efficiently by Arg released from carboxypeptidase substrates than free Arg. These studies reveal a novel mechanism by which the Arg supply for NO production in inflammatory conditions may be maintained.

Noninflammatory Expression of E-Selectin Is Regulated by Cell Growth

Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3785-3791
Author(s):  
Jianying Luo ◽  
Gretchen Paranya ◽  
Joyce Bischoff
Keyword(s):  
Endothelial Cells ◽  
Interleukin 1 ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Microvascular Endothelial Cells ◽  
Proliferating Cells ◽  
Microvascular Endothelial ◽  
In Cells

E-selectin, an endothelial-specific adhesion molecule best known for its role in leukocyte adhesion, is not detected in quiescent endothelial cells, but is induced by inflammatory stimuli. However, E-selectin is also expressed in proliferating endothelial cells under noninflammatory conditions in vivo and in vitro, suggesting that E-selectin is also regulated by growth signals. To investigate E-selectin expression in lipopolysaccharide-stimulated versus nonstimulated proliferating cells, we analyzed the distribution of E-selectin–positive human microvascular endothelial cells in G0/G1, S, and G2/M phases of the cell cycle under both conditions. Lipopolysaccharide treatment resulted in uniformly increased E-selectin expression in cells in G0/G1, S, and G2/M. In contrast, levels of E-selectin in nonstimulated proliferating cells showed a linear correlation with the percentage of cells in G2/M. E-selectin in proliferating endothelial cells was not reduced by addition of soluble tumor necrosis factor-–receptor or soluble interleukin-1–receptor indicating that its expression was not due to endogenous production of either cytokine. In addition, E-selectin was increased in cells stimulated with basic fibroblast growth factor, a well-known mitogen for endothelial cells. E-selectin in proliferating endothelial cells is functional, as shown by E-selectin–dependent adhesion of the promyelocytic leukemia cell line HL-60 to subconfluent human microvascular endothelial cells. In summary, these studies indicate that E-selectin can be regulated by a non-inflammatory pathway that is related to the proliferative state of the endothelium.

Noninflammatory Expression of E-Selectin Is Regulated by Cell Growth

Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3785-3791 ◽  
Author(s):  
Jianying Luo ◽  
Gretchen Paranya ◽  
Joyce Bischoff
Keyword(s):  
Endothelial Cells ◽  
Interleukin 1 ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Microvascular Endothelial Cells ◽  
Proliferating Cells ◽  
Microvascular Endothelial ◽  
In Cells

Abstract E-selectin, an endothelial-specific adhesion molecule best known for its role in leukocyte adhesion, is not detected in quiescent endothelial cells, but is induced by inflammatory stimuli. However, E-selectin is also expressed in proliferating endothelial cells under noninflammatory conditions in vivo and in vitro, suggesting that E-selectin is also regulated by growth signals. To investigate E-selectin expression in lipopolysaccharide-stimulated versus nonstimulated proliferating cells, we analyzed the distribution of E-selectin–positive human microvascular endothelial cells in G0/G1, S, and G2/M phases of the cell cycle under both conditions. Lipopolysaccharide treatment resulted in uniformly increased E-selectin expression in cells in G0/G1, S, and G2/M. In contrast, levels of E-selectin in nonstimulated proliferating cells showed a linear correlation with the percentage of cells in G2/M. E-selectin in proliferating endothelial cells was not reduced by addition of soluble tumor necrosis factor-–receptor or soluble interleukin-1–receptor indicating that its expression was not due to endogenous production of either cytokine. In addition, E-selectin was increased in cells stimulated with basic fibroblast growth factor, a well-known mitogen for endothelial cells. E-selectin in proliferating endothelial cells is functional, as shown by E-selectin–dependent adhesion of the promyelocytic leukemia cell line HL-60 to subconfluent human microvascular endothelial cells. In summary, these studies indicate that E-selectin can be regulated by a non-inflammatory pathway that is related to the proliferative state of the endothelium.

Stimulation of Tetrahydrobiopterin Synthesis by Cyclosporin A during Lipopolysaccharide Treatment in Vascular Endothelial Cells

Pteridines ◽  
2002 ◽  
Vol 13 (3) ◽  
pp. 89-93
Author(s):  
Masakazu Ishii ◽  
Shunichi Shimizu ◽  
Kazuhiro Shiota ◽  
Shinichiro Yamamoto ◽  
Yuji Kiuchi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cyclosporin A ◽  
Vascular Endothelial Cells ◽  
Mrna Level ◽  
Microvascular Endothelial Cells ◽  
Inos Mrna ◽  
No Production ◽  
Brain Microvascular Endothelial Cells ◽  
Microvascular Endothelial ◽  
Lps Treatment

Abstract We examined the effect of immunosuppressant cyclosporin A (CsA) on the synthesis of tetrahydrobiopterin (BH4), which is a cofactor for nitric oxide synthase (NOS), during treatment with lipopolysaccharide (LPS) in mouse brain microvascular endothelial cells. Addition of LPS to the endothelial cells increased the BH4 content and the mRNA level of GTP-cyclohydrolase I (GTPCH), the rate-limiting enzyme of BH4 synthesis, and the LPSínduced increases in both the BH4 content and expression of GTPCH mRNA were further stimulated by the cotreatment with CsA. 2,4-Diamino-6-hydroxypyrimidine, an inhibitor of GTPCH, blocked the increase in BH4 content induced by CsA during the LPS treatment. Moreover. CsA stimulated the expression of inducible NOS (iNOS) mRNA during the LPS treatment. These findings suggest that CsA stimulates LPS-induced BH4 synthesis through the induction of GTPCH, and iNOS expression. CsA may increase NO production during LPS treatment in brain microvascular endothelial cells.

Sign in / Sign up

Export Citation Format

Share Document