The major source of """"""""high-output"""""""" nitric oxide (NO) during inflammation is inducible NO synthase (iNOS). Although iNOS is a transcriptionally-regulated generator of high NO, we have discovered a novel mode of post- translational, G protein coupled receptor (GPCR)-mediated activation of iNOS via ERK-dependent phosphorylation in endothelial cells. Post-translational activation of iNOS results in a further 3- to 5-fold increase in NO concentration over its already high basal amount. In Project 2, we will address the mechanisms by which iNOS phosphorylation leads to high output NO production and how this influences the lung endothelial barrier. We will test the hypotheses that (i) activation of the kinin GPCR, BI, induces ?-arrestin2 scaffolding of iNOS and ERK, which in turn phosphorylates and activates iNOS due to enhanced dimerization and isomerization by the prolyl isomerase Pin1, (ii) S-nitrosylation of ?-arrestin2 dissociates it from iNOS, resulting in dephosphorylation and inactivation ,and (iii) post-translationally activated iNOS-derived NO causes increased lung vascular permeability in the context of NADPH oxidase (NOX2) activation and peroxynitrite generation resulting in endocytosis of VE-cadherin and inactivation of p190RhoGAP. The signaling pathways mediating receptor-dependent post-translational activation of iNOS in pulmonary endothelial cells and its effects on pulmonary vascular permeability will be investigated using imaging, cell biology, biochemical, and physiological approaches. We will thereby establish the role of key signaling molecules ?-arrestin2 and Pin1 in mediating INOS activation and functions of ?-arrestin2, p190RhoGAP and VE-cadherin in mediating disruption of lung endothelial barrier function. The proposed studies we hope will provide novel therapeutic strategies to inhibit detrimental consequences of high concentrations of NO in inflammatory lung injury based on the deeper understanding of signaling pathways by which iNOS is activated secondary to its expression in the endothelium.
Nitric oxide is an important signaling molecule made by blood vessels and during infection or inflammation, high levels of this molecule can be generated to cause damage to the lung. The proposed studies will investigate mechanisms by which vascular endothelial cells generate high levels of nitric oxide and how this affects the permeability or leakiness of lung vessels. We hope our findings will provide novel therapeutic strategies to inhibit detrimental consequences of high nitric oxide in inflammatory lung injury.
|Di, Anke; Mehta, Dolly; Malik, Asrar B (2016) ROS-activated calcium signaling mechanisms regulating endothelial barrier function. Cell Calcium 60:163-71|
|Tauseef, Mohammad; Farazuddin, Mohammad; Sukriti, Sukriti et al. (2016) Transient receptor potential channel 1 maintains adherens junction plasticity by suppressing sphingosine kinase 1 expression to induce endothelial hyperpermeability. FASEB J 30:102-10|
|Gong, Haixia; An, Shejuan; Sassmann, Antonia et al. (2016) PAR1 Scaffolds TGFÎ²RII to Downregulate TGF-Î² Signaling and Activate ESC Differentiation to Endothelial Cells. Stem Cell Reports 7:1050-1058|
|Rajput, Charu; Tauseef, Mohammad; Farazuddin, Mohammad et al. (2016) MicroRNA-150 Suppression of Angiopoetin-2 Generation and Signaling Is Crucial for Resolving Vascular Injury. Arterioscler Thromb Vasc Biol 36:380-8|
|Ebenezer, David L; Fu, Panfeng; Suryadevara, Vidyani et al. (2016) Epigenetic regulation of pro-inflammatory cytokine secretion by sphingosine 1-phosphate (S1P) in acute lung injury: Role of S1P lyase. Adv Biol Regul :|
|Zimnicka, Adriana M; Husain, Yawer S; Shajahan, Ayesha N et al. (2016) Src-dependent phosphorylation of caveolin-1 Tyr-14 promotes swelling and release of caveolae. Mol Biol Cell 27:2090-106|
|Jiang, Ying; Sverdlov, Maria S; Toth, Peter T et al. (2016) Phosphatidic Acid Produced by RalA-activated PLD2 Stimulates Caveolae-mediated Endocytosis and Trafficking in Endothelial Cells. J Biol Chem 291:20729-38|
|Liu, Yuru; Kumar, Varsha Suresh; Zhang, Wei et al. (2015) Activation of type II cells into regenerative stem cell antigen-1(+) cells during alveolar repair. Am J Respir Cell Mol Biol 53:113-24|
|Geyer, Melissa; Huang, Fei; Sun, Ying et al. (2015) Microtubule-Associated Protein EB3 Regulates IP3 Receptor Clustering and Ca(2+) Signaling in Endothelial Cells. Cell Rep 12:79-89|
|Zhang, Xianming; Brovkovych, Viktor; Zhang, Yongkang et al. (2015) Downregulation of kinin B1 receptor function by B2 receptor heterodimerization and signaling. Cell Signal 27:90-103|
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