0000000000135550
AUTHOR
Sales Ibiza
Endothelial Nitric Oxide Synthase Regulates T Cell Receptor Signaling at the Immunological Synapse
The role of nitric oxide (NO) in T cells remains controversial, and the origin and localization of endogenous NO and whether it regulates lymphocyte activation are unclear. We show here that, within minutes of binding to antigen, T cells produce NO via endothelial nitric oxide synthase (eNOS). This process required increased intracellular Ca2+ and phosphoinositide3-kinase activity. By using an eNOS-green fluorescent fusion protein and fluorescent probes to detect NO, we show that eNOS translocates with the Golgi apparatus to the immune synapse of T helper cells engaged with antigen-presenting cells (APC), where it was fully activated. Overexpression of eNOS prevented the central coalescence…
Gastrin induces the interaction between human mononuclear leukocytes and endothelial cells through the endothelial expression of P-selectin and VCAM-1.
Gastric mucosal inflammation is frequently associated with hypergastrinemia, and a correlation exists between the level of gastrin and degree of gastritis. We have previously observed that gastrin promotes leukocyte-endothelial interactions and contributes to Helicobacter -induced inflammation in the rat mesentery. In the present study, we aimed to evaluate a possible proinflammatory activity of gastrin in humans. The interaction between human leukocytes [U-937 cells, peripheral blood polymorphonuclear (PMN), and peripheral blood mononuclear (PBMC) cells] and human umbilical vein endothelial cells (HUVEC) was analyzed in static and dynamic conditions. The endothelial expression of adhesion …
eNOS S-nitrosylates β-actin on Cys374 and regulates PKC-θ at the immune synapse by impairing actin binding to profilin-1.
The actin cytoskeleton coordinates the organization of signaling microclusters at the immune synapse (IS); however, the mechanisms involved remain poorly understood. We show here that nitric oxide (NO) generated by endothelial nitric oxide synthase (eNOS) controls the coalescence of protein kinase C-¿ (PKC-¿) at the central supramolecular activation cluster (c-SMAC) of the IS. eNOS translocated with the Golgi to the IS and partially colocalized with F-actin around the c-SMAC. This resulted in reduced actin polymerization and centripetal retrograde flow of ß-actin and PKC-¿ from the lamellipodium-like distal (d)-SMAC, promoting PKC-¿ activation. Furthermore, eNOS-derived NO S-nitrosylated ß-…
Complex I dysfunction and tolerance to nitroglycerin: an approach based on mitochondrial-targeted antioxidants.
Nitroglycerin (GTN) tolerance was induced in vivo (rats) and in vitro (rat and human vessels). Electrochemical detection revealed that the incubation dose of GTN (5×10 −6 mol/L) did not release NO or modify O 2 consumption when administered acutely. However, development of tolerance produced a decrease in both mitochondrial O 2 consumption and the K m for O 2 in animal and human vessels and endothelial cells in a noncompetitive action. GTN tolerance has been associated with impairment of GTN biotransformation through inhibition of aldehyde dehydrogenase (ALDH)-2, and with uncoupling of mitochondrial respiration. Feeding rats with mitochondrial-targeted antioxidants (mitoquinone [MQ]) and i…