Atherosclerosis in animals and humans is characterized by an unresponsiveness of arteries and arterioles to endothelium-dependent vasodilators. Recent studies indicate that high cholesterol and/or LDL could play a significant role in inducing such alteration by reducing the synthesis of the endothelial-derived relaxing factor; nitric oxide (NO). AS reduction in the production of NO by the vessel wall could promote smooth muscle cell proliferation in the intima and platelet aggregation, adhesion, and degranulation, which appear to be important events in atherosclerosis and vascular pathologies. However, the precise mechanism by which NO synthesis is impaired by high cholesterol has not been defined. Substantial evidence support the notion that high cholesterol and/or LDL levels affect a step involving the transport of L-arginine, the precursor of NO in endothelial cells. Indeed, preliminary evidence obtained by the applicant indicates that high cholesterol significantly reduces L-arginine transport in these cells. However, evidence is lacking concerning the status of l-arginine transport in hypercholesterolemic states. The proposed research plan will focus on L-arginine transport in vascular endothelial cells to determine its role in the dysfunction induced by high cholesterol (LDL) states.
The specific aims are; 1) To provide a detailed characterization of L- arginine transport in vascular endothelial cells. This section will include studies to define the kinetic behavior of L-[3H]arginine transport, membrane potential dependence, the effect of external pH changes, and competition studies to determine the selectivity of the transport mechanism. 2) To evaluate the effect of cholesterol and LDL/oxidized LDL on arginine transport in basal and stimulated conditions and 3), to identify possible sites of action of these agents by determining the pathway(s) regulating arginine transport under normal and altered conditions (high cholesterol/LDL). For this purpose, the role of the receptor-mediated calcium mobilization (G-proteins; InsP3/Ca2+; DAG/PkC, Ca2+/calmodulin, etc.) in the regulation of arginine transport will be determined using pharmacological agents that selectively inhibit the different steps of the phosphoinositol cascade, Ca2+/calmodulin-dependent processes, etc. Similar experiments will be conducted measuring NO release to assess the coupling between arginine transport and NO synthesis. The role of membrane potential changes as a link between the activation of NO synthesis and L-arginine transport will be evaluated. The proposed research program will contribute to our basic understanding of the cellular mechanisms underlying normal and altered amino acid transport in relationship to endothelial dysfunction int he pathogenesis of atherosclerosis, hypertension and congestive heart failure.
Rijpma, Sanna R; van der Velden, Maarten; González-Pons, Maria et al. (2016) Multidrug ATP-binding cassette transporters are essential for hepatic development of Plasmodium sporozoites. Cell Microbiol 18:369-83 |
Padín-Irizarry, Vivian; Colón-Lorenzo, Emilee E; Vega-Rodríguez, Joel et al. (2016) Glutathione-deficient Plasmodium berghei parasites exhibit growth delay and nuclear DNA damage. Free Radic Biol Med 95:43-54 |
Jardón, Javier; Izquierdo, Natalio J; Renta, Jessica Y et al. (2016) Ocular Findings in Patients with the Hermansky-Pudlak Syndrome (Types 1 and 3). Ophthalmic Genet 37:89-94 |
Rivera-Peña, Bianca; Ruíz-Fullana, Francisco J; Vélez-Reyes, Germán L et al. (2016) HPV-16 infection modifies overall survival of Puerto Rican HNSCC patients. Infect Agent Cancer 11:47 |
Velásquez-Martínez, Maria C; Vázquez-Torres, Rafael; Rojas, Legier V et al. (2015) Alpha-1 adrenoreceptors modulate GABA release onto ventral tegmental area dopamine neurons. Neuropharmacology 88:110-21 |
Vega-Rodríguez, Joel; Pastrana-Mena, Rebecca; Crespo-Lladó, Keila N et al. (2015) Implications of Glutathione Levels in the Plasmodium berghei Response to Chloroquine and Artemisinin. PLoS One 10:e0128212 |
Zenón, Frances; Cantres-Rosario, Yisel; Adiga, Radhika et al. (2015) HIV-infected microglia mediate cathepsin B-induced neurotoxicity. J Neurovirol 21:544-58 |
Segarra, Annabell C; Torres-Díaz, Yvonne M; Silva, Richard D et al. (2014) Estrogen receptors mediate estradiol's effect on sensitization and CPP to cocaine in female rats: role of contextual cues. Horm Behav 65:77-87 |
Ortiz, A P; Unger, E R; Muñoz, C et al. (2014) Cross-sectional study of HPV-16 infection in a population-based subsample of Hispanic adults. BMJ Open 4:e004203 |
Rosas, Odrick R; Torrado, Aranza I; Santiago, Jose M et al. (2014) Long-term treatment with PP2 after spinal cord injury resulted in functional locomotor recovery and increased spared tissue. Neural Regen Res 9:2164-73 |
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