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Carrillo-Sepúlveda MA, Ceravolo GS, Furstenau CR, Monteiro PDS, Bruno-Fortes Z, Carvalho MH, Laurindo FR, Tostes RC, Webb RC, Barreto-Chaves MLM. Emerging role of angiotensin type 2 receptor (AT2R)/Akt/NO pathway in vascular smooth muscle cell in the hyperthyroidism. PLoS One 2013; 8:e61982. [PMID: 23637941 PMCID: PMC3634851 DOI: 10.1371/journal.pone.0061982] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/15/2013] [Indexed: 12/14/2022] Open
Abstract
Hyperthyroidism is characterized by increased vascular relaxation and decreased vascular contraction and is associated with augmented levels of triiodothyronine (T3) that contribute to the diminished systemic vascular resistance found in this condition. T3 leads to augmented NO production via PI3K/Akt signaling pathway, which in turn causes vascular smooth muscle cell (VSMC) relaxation; however, the underlying mechanisms involved remain largely unknown. Evidence from human and animal studies demonstrates that the renin-angiotensin system (RAS) plays a crucial role in vascular function and also mediates some of cardiovascular effects found during hyperthyroidism. Thus, in this study, we hypothesized that type 2 angiotensin II receptor (AT2R), a key component of RAS vasodilatory actions, mediates T3 induced-decreased vascular contraction. Marked induction of AT2R expression was observed in aortas from T3-induced hyperthyroid rats (Hyper). These vessels showed decreased protein levels of the contractile apparatus: α-actin, calponin and phosphorylated myosin light chain (p-MLC). Vascular reactivity studies showed that denuded aortic rings from Hyper rats exhibited decreased maximal contractile response to angiotensin II (AngII), which was attenuated in aortic rings pre-incubated with an AT2R blocker. Further study showed that cultured VSMC stimulated with T3 (0.1 µmol/L) for 24 hours had increased AT2R gene and protein expression. Augmented NO levels and decreased p-MLC levels were found in VSMC stimulated with T3, both of which were reversed by a PI3K/Akt inhibitor and AT2R blocker. These findings indicate for the first time that the AT2R/Akt/NO pathway contributes to decreased contractile responses in rat aorta, promoted by T3, and this mechanism is independent from the endothelium.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Disease Models, Animal
- Gene Expression Regulation/drug effects
- Hyperthyroidism/genetics
- Hyperthyroidism/metabolism
- Male
- Models, Biological
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Nitric Oxide/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Rats
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Signal Transduction/drug effects
- Triiodothyronine/pharmacology
- Vasoconstriction/drug effects
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Affiliation(s)
- Maria Alícia Carrillo-Sepúlveda
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Graziela S. Ceravolo
- Laboratory of Hypertension, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Cristina R. Furstenau
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Priscilla de Souza Monteiro
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Zuleica Bruno-Fortes
- Laboratory of Hypertension, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Maria Helena Carvalho
- Laboratory of Hypertension, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Francisco R. Laurindo
- Vascular Biology Laboratory of Heart Institute, University of Sao Paulo, Sao Paulo, Brazil
| | - Rita C. Tostes
- Laboratory of Hypertension, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
- Department of Physiology, Georgia Health Science University, Augusta, Georgia, United States of America
| | - R. Clinton Webb
- Department of Physiology, Georgia Health Science University, Augusta, Georgia, United States of America
| | - Maria Luiza M. Barreto-Chaves
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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da Silva OG, Rossignoli PDS, Carrillo-Sepúlveda MA, Barreto-Chaves MLM, Chies AB. Involvement of the AT1 receptor in the venoconstriction induced by angiotensin II in both the inferior vena cava and femoral vein. Peptides 2011; 32:112-7. [PMID: 20955746 DOI: 10.1016/j.peptides.2010.10.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 10/08/2010] [Accepted: 10/08/2010] [Indexed: 11/25/2022]
Abstract
Although angiotensin II-induced venoconstriction has been demonstrated in the rat vena cava and femoral vein, the angiotensin II receptor subtypes (AT(1) or AT(2)) that mediate this phenomenon have not been precisely characterized. Therefore, the present study aimed to characterize the pharmacological receptors involved in the angiotensin II-induced constriction of rat venae cavae and femoral veins, as well as the opposing effects exerted by locally produced prostanoids and NO upon induction of these vasomotor responses. The obtained results suggest that both AT(1) and AT(2) angiotensin II receptors are expressed in both veins. Angiotensin II concentration-response curves were shifted toward the right by losartan but not by PD 123319 in both the vena cava and femoral vein. Moreover, it was observed that both 10(-5)M indomethacin and 10(-4)M L-NAME improve the angiotensin II responses in the vena cava and femoral vein. In conclusion, in the rat vena cava and femoral vein, angiotensin II stimulates AT(1) but not AT(2) to induce venoconstriction, which is blunted by vasodilator prostanoids and NO.
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Barreto-Chaves MLM, Carrillo-Sepúlveda MA, Carneiro-Ramos MS, Gomes DA, Diniz GP. The crosstalk between thyroid hormones and the Renin-Angiotensin System. Vascul Pharmacol 2009; 52:166-70. [PMID: 19857605 DOI: 10.1016/j.vph.2009.10.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 10/18/2009] [Indexed: 12/25/2022]
Abstract
Thyroid hormones (THs) exert multiple effects on the heart and vascular system. As a consequence, altered cardiovascular function observed in the thyroid diseases corresponds to one of the most important and clinically relevant aspects found in both hyperthyroidism and hypothyroidism. Besides THs' direct effects on the heart and vascular system, in the last three decades several studies have implicated the Renin-Angiotensin System (RAS) in some of the cardiovascular effects of THs, with this interaction suggesting that RAS may be an important mediator of THs actions. In the present review, we discuss the alterations in the circulating RAS, as well as modifications in cardiac and vascular RAS which are involved in the cardiovascular alterations found during the modulation of TH levels. In addition, considering the important role that both systems present during fetal and neonatal periods, we also review the interaction between THs and the RAS in the development of cardiovascular system. A greater understanding of the role of the RAS in hyperthyroidism and hypothyroidism, during early or adult life will presumably facilitate the evolution of newer, targeted therapies.
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Affiliation(s)
- Maria Luiza M Barreto-Chaves
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences of University of São Paulo, São Paulo, Brazil.
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Carrillo-Sepúlveda MA, Ceravolo GS, Fortes ZB, Carvalho MH, Tostes RC, Laurindo FR, Webb RC, Barreto-Chaves MLM. Thyroid hormone stimulates NO production via activation of the PI3K/Akt pathway in vascular myocytes. Cardiovasc Res 2009; 85:560-70. [PMID: 19734167 DOI: 10.1093/cvr/cvp304] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIMS Thyroid hormone (TH) rapidly relaxes vascular smooth muscle cells (VSMCs). However, the mechanisms involved in this effect remain unclear. We hypothesize that TH-induced rapid vascular relaxation is mediated by VSMC-derived nitric oxide (NO) production and is associated with the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signalling pathway. METHODS AND RESULTS NO levels were determined using a NO-specific fluorescent dye (DAF-2) and nitrite (NO2-) levels. Expression of NO synthase (NOS) isoforms and proteins of the PI3K/Akt pathway was determined by both western blotting and immunocytochemistry. Myosin light chain (MLC) phosphorylation levels were also investigated by western blotting. Exposure of cultured VSMCs from rat thoracic aortas to triiodothyronine (T3) resulted in a significant decrease of MLC phosphorylation levels. T3 also induced a rapid increase in Akt phosphorylation and increased NO production in a dose-dependent manner (0.001-1 microM). VSMCs stimulated with T3 for 30 min showed an increase in the expression of all three NOS isoforms and augmented NO production, effects that were prevented by inhibitors of PI3K. Vascular reactivity studies showed that vessels treated with T3 displayed a decreased response to phenylephrine, which was reversed by NOS inhibition. These data suggest that T3 treatment induces greater generation of NO both in aorta and VSMCs and that this phenomenon is endothelium independent. In addition, these findings show for the first time that the PI3K/Akt signalling pathway is involved in T3-induced NO production by VSMCs, which occurs with expressive participation of inducible and neuronal NOS. CONCLUSION Our data strongly indicate that T3 causes NO-dependent rapid relaxation of VSMC and that this effect is mediated by the PI3K/Akt signalling pathway.
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Affiliation(s)
- Maria Alícia Carrillo-Sepúlveda
- Laboratory of Cell Biology and Functional Anatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Avenida Professor Lineu Prestes 2415, Sao Paulo 05508-900, Brazil
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