Antihypertensive Mechanism of Lactoferrin-Derived Peptides: Angiotensin Receptor Blocking Effect

Texto del artículo, no incluye figuras ni tablas.Looking for antihypertensive mechanisms beyond ACE inhibition, we assessed whether lactoferrin (LF)-derived peptides can act as receptor blockers to inhibit vasoconstriction induced by angiotensin II or endothelin-1. The lactoferricin B (LfcinB)-derived peptide LfcinB20–25 (RRWQWR), the low molecular weight LF hydrolysate (LFH < 3 kDa), and two peptides identified in LFH < 3 kDa (LIWKL and RPYL) were tested in ex vivo assays of vasoactive responses. The peptide RPYL was tested in radioligand receptor binding assays. Both LFH < 3 kDa and individual peptides inhibited angiotensin II-induced vasoconstriction. RPYL showed the highest ex vivo inhibitory effect and also inhibited binding of [125I]-(Sar1,Ile8)-angiotensin II to AT1 receptors. By contrast, neither LFH < 3 kDa nor RPYL inhibited endothelin-1 and depolarization-induced vasoconstrictions. In conclusion, LF-derived peptides selectively inhibit angiotensin II-induced vasoconstriction by blocking angiotensin AT1 receptors. Therefore, inhibition of angiotensin II-induced vasocontriction is suggested as a mechanism contributing along with ACE inhibition to the antihypertensive effect of some LF-derived peptides.This work was supported by Grants AGL2010-21009 from Ministerio de Educación y Ciencia – FEDER, Consolider Ingenio 2010, Fun-C-Food, CSD2007-00063, and network RETICS INVICTUS – RD12/0014/0004 from Instituto de Salud Carlos III. R. Fernández-Musoles is the recipient of a fellowship from Ministerio de Educación y Ciencia (BES-2008-004472).Peer reviewe

Abacavir increases purinergic P2X7 receptor activation by ATP: does a pro-inflammatory synergism underlie its cardiovascular toxicity?

16 p.-9 fig.-1 tab.The cardiovascular toxicity of Abacavir is related to its purinergic structure. Purinergic P2X7-receptors (P2X7R), characterized by activation by high concentrations of ATP and with high plasticity, seem implicated. We appraise the nature of the interplay between Abacavir and P2X7R in generating vascular inflammation. The effects of Abacavir on leukocyte-endothelium interactions were compared with those of its metabolite carbovir triphosphate (CBV-TP) or ATP in the presence of apyrase (ATP-ase) or A804598 (P2X7R-antagonist). CBV-TP and ATP levels were evaluated by HPLC, while binding of Abacavir, CBV-TP and ATP to P2X7R was assessed by radioligand and docking studies. Hypersensitivity studies explored a potential allosteric action of Abacavir. Clinical concentrations of Abacavir (20 µmol/L) induced leukocyte-endothelial cell interactions by specifically activating P2X7R, but the drug did not show affinity for the P2X7R ATP-binding site (site 1). CBV-TP levels were undetectable in Abacavir-treated cells, while those of ATP were unaltered. The effects of Abacavir were Apyrase-dependent, implying dependence on endogenous ATP. Exogenous ATP induced a profile of proinflammatory actions similar to Abacavir, but was not entirely P2X7R-dependent. Docking calculations suggested ATP-binding to sites 1 and 2, and Abacavir-binding only to allosteric site 2. A combination of concentrations of Abacavir (1 µmol/L) and ATP (0.1 µmol/L) that had no effect when administered separately induced leukocyte-endothelium interactions mediated by P2X7R and involving Connexin43 channels. Therefore, Abacavir acts as a positive allosteric modulator of P2X7R, turning low concentrations of endogenous ATP themselves incapable of stimulating P2X7R into a functional proinflammatory agonist of the receptor.This work was supported by Ministerio de Economía y Competitividad and the European Regional Development fund of the European Union (FEDER) (SAF2015–67678-R, RTI2018-094436-B-I00 and CTQ2017-88353-R), Ministerio de Sanidad y Consumo (CB06/04/0071, CIBERehd) and Generalitat Valenciana (PROMETEOII/2014/035 and PROMETEO 2018/141), along with an unrestricted grant from GILEAD S.L. VCD and ASL were funded by VALI + D program from Generalitat Valenciana (grants number ACIF/2015/316 and ACIF/2016/119, respectively) and PGM by FPU program from Ministerio de Educación, Cultura y Deporte (grant number FPU16/06064) and MABR by FPU program from Ministerio de Ciencia, Innovación y Universidades (grant number FPU17/04249).Peer reviewe

Alpha1-adrenoceptors in the rat cerebral cortex: new insights into the characterization of alpha1L-and alpha1D-adrenoceptors

36 p., figuras y tablas, bibliografíaAmong the three alpha1-adrenoceptor subtypes (alpha1A, alpha1B and alpha1D) a peculiar intracellular localization and poor coupling to membrane signals of cloned alpha1D-adrenoceptor has been reported. In addition, the alpha1L-adrenoceptor (low affinity for prazosin), a functional phenotype of alpha1A, has been described. The purpose of this work was to analyze the expression, cellular localization and coupling to membrane signalling (inositol phosphate accumulation) of alpha1-adrenoceptor subtypes in a native tissue, the rat cerebral cortex. mRNA for the three subtypes was quantified by real-time RT-PCR (alpha1D>alpha1B>>alpha1A). Alpha1-adrenoceptors were also detected by immunoblotting, revealing alpha1A- and alpha1B-adrenoceptors to be predominantly expressed in the membrane fraction and the alpha1D-adrenoceptor to be localized in the cytosolic fraction. Competitive radioligand binding studies revealed the presence of alpha1D-adrenoceptor in tissue homogenates, whereas only alpha1A- and alpha1B-subtypes were detected in membranes. The proportion of alpha1A-adrenoceptor increased after treatment with noradrenaline, suggesting differences in agonist-mediated trafficking. Saturation experiments detected high- and low (alpha1A/L)-prazosin binding sites, the latter of which disappeared on incubation with GppNHp. The alpha1A/L-adrenoceptor was heavily implicated in the inositol phosphate response, while the alpha1D-subtype did not play a relevant role. These results suggest that the predominant cytosolic localization of alpha1D-adrenoceptor lies behind its poor coupling to membrane signalling such as inositol phosphate pathway. The fact that the alpha1Ladrenoceptor detected in radioligand binding studies disappeared in the presence of GppNHp implies that it represents a conformational state of the alpha1A-adrenoceptor coupled to G protein.This study was supported by the Spanish Dirección General de Programas y Transferencia de Conocimiento del Ministerio de Ciencia e Innovación (Grant SAF2004-01541 and SAF2007-62120); and Instituto de Salud Carlos III, Fondo de Investigaciones Sanitarias (Grant FIS PI070509). Vanessa Segura, Nicla Flacco and Eduardo Oliver are financed by the Spanish Ministry of Education and Science (Fellowships BES-2005-108383, AP-2005-5076 and AP-2004-3536).Peer reviewe

Correlation between mRNA levels and functional role of 1-adrenoceptor subtypes in arteries: evidence of 1L as a functional isoform of the 1A-adrenoceptor

10 pages, 3 figures, 10 tables.-- PMID: 15951348 [PubMed]The mRNA levels for the three alpha1-adrenoceptor subtypes, alpha1A, alpha1B, and alpha1D, were quantified by real-time RT-PCR in arteries from Wistar rats. The alpha1D-adrenoceptor was prominent in both aorta (79.0%) and mesenteric artery (68.7%), alpha1A predominated in tail (61.7%) and small mesenteric artery (73.3%), and both alpha1A- and alpha1D-subtypes were expressed at similar levels in iliac artery. The mRNA levels of the alpha1B-subtype were a minority in all vessels (1.7-11.1%). Concentration-response curves of contraction in response to phenylephrine or relaxation in response to alpha1-adrenoceptor antagonists on maximal sustained contraction induced by phenylephrine were constructed from control vessels and vessels pretreated with 100 micromol/l chloroethylclonidine (CEC) for 30 min. The significant decrease in the phenylephrine potency observed after CEC treatment together with the inhibitory potency displayed by 8-{2-[4-(2-methoxyphenyl)-1-piperazinyl]-8-azaspiro (4,5) decane-7-dionedihydrochloride} (BMY-7378, an alpha1D-adrenoceptor antagonist) confirm the relevant role of alpha1D-adrenoceptors in aorta and iliac and proximal mesenteric arteries. The potency of 5-methylurapidil (an alpha1A-adrenoceptor antagonist) and the changes in the potency of both BMY-7378 and 5-methylurapidil after CEC treatment provided evidence of a mixed population of alpha1A- and alpha1D-adrenoceptors in iliac and distal mesenteric arteries. The low potency of prazosin (pIC50 < 9) as well as the high 5-methylurapidil potency in tail and small mesenteric arteries suggest the main role of alpha1A/alpha1L-adrenoceptors with minor participation of the alpha1D-subtype. The mRNA levels and CEC treatment corroborated this pattern and confirmed that the alpha1L-adrenoceptor could be a functional isoform of the alpha1A-subtype.This work was supported by a research grant from the Spanish Comisión Interministerial de Ciencia y Tecnología (SAF2001-2656). Daniel Martí Canet received a fellowship from Universidad Cardenal Herrera-CEU.Peer reviewe

β-Adrenoceptors differentially regulate vascular tone and angiogenesis of rat aorta via ERK1/2 and p38

β-Adrenoceptors (β-ARs) modulate ERK1/2 and p38 in different cells, but little is known about the contribution of these signaling pathways to the function of β-ARs in vascular tissue. Immunoblotting analysis of rat aortic rings, primary endothelial (ECs) and smooth muscle cells (SMCs) isolated from aorta showed that β-AR stimulation with isoprenaline activated p38 in aortic rings and in both cultured cell types, whereas it had a dual effect on ERK1/2 phosphorylation, decreasing it in ECs while increasing it in SMCs. These effects were reversed by propranolol, which by itself increased p-ERK1/2 in ECs. Isoprenaline β-AR mediated vasodilation of aortic rings was potentiated by the ERK1/2 inhibitor, U0126, in the presence or absence of endothelium or L-NAME, whereas inhibition of p38 had no impact. Isoprenaline moderately decreased sprouting from aorta rings in the Matrigel angiogenesis assay; conversely propranolol not only prevented isoprenaline inhibition, but stimulated angiogenesis. ERK1/2 inhibition decreased angiogenesis, while a dramatic stimulation was observed by p38 blockade. Our results suggest that ERK1/2 activation after β-ARs stimulation in the smooth muscle hinders the vasodilator effect of isoprenaline, but in the endothelium β-ARs decreases ERK1/2 and increases p38 activity reducing therefore angiogenesis

Role of α-Adrenergic Receptors in the Effect of the β-Adrenergic Receptor Ligands, CGP 12177, Bupranolol, and SR 59230A, on the Contraction of Rat Intrapulmonary Artery

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The impact of alpha1-adrenoceptors up-regulation accompanied by the impairment of beta-adrenergic vasodilatation in hypertension

9 pages, 7 figures, 3 tables.-- PMID: 19060223 [PubMed]In human and animal hypertension models, increased activity of G-protein-coupled receptor kinase (GRK) 2 determines a generalized decrease of beta-adrenergic vasodilatation. We analyzed the possibility of differential changes in the expression and functionality of alpha(1A), alpha(1B), alpha(1D), beta(1), beta(2), and beta(3)-ARs also being involved in the process. We combined the quantification of mRNA levels with immunoblotting and functional studies in aortas of young and adult spontaneously hypertensive rats (SHRs) and their controls (Wistar Kyoto). We found the expression and function of beta(1)-adrenoceptors in young prehypertensive SHRs to be higher, whereas a generalized increase in the expression of the six adrenoceptors and GRK2 was observed in aortas of adult hypertensive SHRs. alpha(1D)- and beta(3)-adrenoceptors, the subtypes that are more resistant to GRK2-mediated internalization and mostly expressed in rat aorta, exhibited an increased functional role in hypertensive animals, showing two hemodynamic consequences: 1) an increased sensitivity to the vasoconstrictor stimulus accompanied by a decreased sensitivity to the vasodilator stimulus (alpha(1D)-ARs are the most sensitive to agonists, and beta(3)-ARs are the least sensitive to agonists); and 2) a slower recovery of the basal tone after adrenergic stimulus removal because of the kinetic characteristic of the alpha(1D) subtype. These functional changes might be involved in the greater sympathetic vasoconstrictor tone observed in hypertension.This work was supported by the Spanish Comisión Interministerial de Ciencia y Tecnología [Grant SAF2004-01541]; Generalitat Valenciana [Grants GV2004-B-085, GRUPOS05-038]; and Instituto de Salud Carlos III, Fondo de Investigaciones Sanitarias [Grant FIS PI070509]; and by the Spanish Ministry of Education and Science [Fellowships AP-2004-3536 and AP-2005-5076].Peer reviewe

Inhibiting Cyclin-Dependent Kinase / Cyclin Activity for the Treatment of Cancer and Cardiovascular Disease

17 páginas.-- El documento en word es la versión post-print.Excessive cell proliferation contributes to the pathobiology of human diseases with a high health and socioeconomic impact, including cancer and vascular occlusive diseases (e.g., atherosclerosis, in-stent restenosis, transplant vasculopathy, and vessel bypass graft failure). Recent advances in the understanding of the molecular networks governing the hyperplastic growth of tumors and vascular obstructive neointimal lesions have provided new perspectives for preventive and therapeutic strategies against these disorders. Mammalian cell proliferation requires the activation of several cyclin-dependent protein kinases (CDKs). Postranslational activation of CDKs is a complex process that involves their association with regulatory subunits called cyclins. The activity of CDK / cyclin holoenzymes is negatively regulated through their interaction with members of the CDK family of inhibitory proteins (CKIs). Moreover, over fifty low molecular weight pharmacological CDK inhibitors that target the ATP-binding pocket of the catalytic site of CDKs have been identified. In this review, we will discuss the use of pharmacological and gene therapy strategies against CDK / cyclins in animal models and clinical trials of cancer and cardiovascular disease.Peer reviewe