Characterization of ion channels involved in the proliferative response of femoral artery smooth muscle cells

Producción CientíficaObjective: Vascular smooth muscle cells (VSMCs) contribute significantly to occlusive vascular diseases by virtue of their ability to switch to a noncontractile, migratory, and proliferating phenotype. Although the participation of ion channels in this phenotypic modulation (PM) has been described previously, changes in their expression are poorly defined because of their large molecular diversity. We obtained a global portrait of ion channel expression in contractile versus proliferating mouse femoral artery VSMCs, and explored the functional contribution to the PM of the most relevant changes that we observed. Methods and Results: High-throughput real-time polymerase chain reaction of 87 ion channel genes was performed in 2 experimental paradigms: an in vivo model of endoluminal lesion and an in vitro model of cultured VSMCs obtained from explants. mRNA expression changes showed a good correlation between the 2 proliferative models, with only 2 genes, Kv1.3 and Kvβ2, increasing their expression on proliferation. The functional characterization demonstrates that Kv1.3 currents increased in proliferating VSMC and that their selective blockade inhibits migration and proliferation. Conclusion: These findings establish the involvement of Kv1.3 channels in the PM of VSMCs, providing a new therapeutical target for the treatment of intimal hyperplasia.Ministerio de Sanidad, Consumo y Bienestar Social - Instituto de Salud Carlos III (grants R006/009, FS041139-0 and PI041044)Ministerio de Ciencia, Innovación y Universidades (grants BFU2004-05551 and BFU2007-61524)Junta de Castilla y León (grant GR242

K+ channels expression in hypertension after arterial injury, and effect of selective Kv1.3 blockade with PAP-1 on intimal hyperplasia formation

Producción CientíficaK+ channels are central to vascular pathophysiology. Previous results demonstrated that phenotypic modulation associates with a change in Kv1.3 to Kv1.5 expression, and that Kv1.3 blockade inhibits proliferation of VSMCs cultures. Purpose: To explore whether the Kv1.3 to Kv1.5 switch could be a marker of the increased risk of intimal hyperplasia in essential hypertension and whether systemic treatment with Kv1.3 blockers can prevent intimal hyperplasia after endoluminal lesion . Methods: Morphometric and immunohistochemical analysis were performed in arterial segments following arterial injury and constant infusion of the Kv1.3 blocker PAP-1 during 28 days. Differential expression of K+ channel genes was studied in VSMC from hypertensive (BPH) and normotensive (BPN) mice, both in control and after endoluminal lesion. Finally, the migration and proliferation rate of BPN and BPH VSMCs was explored in vitro. Results: Changes in mRNA expression led to an increased Kv1.3/Kv1.5 ratio in BPH VSMC. Consistent with this, arterial injury in BPH mice induced a higher degree of luminal stenosis, (84±4 % vs. 70±5 % in BPN, p<0.01), although no differences in migration and proliferation rate were observed in cultured VSMCs. The in vivo proliferative lesions were significantly decreased upon PAP-1 systemic infusion (18± 6 % vs. 58±20 % with vehicle, p<0.05). Conclusions: Hypertension leads to a higher degree of luminal stenosis in our arterial injury model, that correlates with a decreased expression of Kv1.5 channels. Kv1.3 blockers decreased in vitro VSMCs proliferation, migration, and in vivo intimal hyperplasia formation, pointing to Kv1.3 channels as promising therapeutical targets against restenosis.La versión original del artículo contiene un error. El gráfico de la página 505 es incorrecto. La corrección del mismo se encuentra en el segundo fichero "Erratum to: K+ Channels Expression in Hypertension After Arterial Injury, and Effect of Selective Kv1.3 Blockade with PAP-1 on Intimal Hyperplasia Formation".Ministerio de Economía, Industria y Competitividad (project RD12/0042/0006)Fondo de Investigación en Salud - Instituto Carlos III (project PI11/00225)VALTEC 09-1-0042Ministerio de Ciencia, Innovación y Universidades (grant BFU2010-15898)Junta de Castilla y León (grant VA094A11-2

Regulator of calcineurin 1 mediates pathological vascular wall remodeling

Angiotensin-II–driven calcineurin activation and regulator of calcineurin-1 (Rcan-1) expression is required for pathological vascular remodeling in mice

Vascular injury triggers Krüppel-like factor 6 mobilization and cooperation with specificity protein 1 to promote endothelial activation through upregulation of the activin receptor-like kinase 1 gene

29 p.-8 figRATIONALE: Activin receptor-like kinase-1 (ALK1) is an endothelial transforming growth factor β receptor involved in angiogenesis. ALK1 expression is high in the embryo vasculature, becoming less detectable in the quiescent endothelium of adult stages. However, ALK1 expression becomes rapidly increased after angiogenic stimuli such as vascular injury. OBJECTIVE: To characterize the molecular mechanisms underlying the regulation of ALK1 on vascular injury. METHODS AND RESULTS: Alk1 becomes strongly upregulated in endothelial (EC) and vascular smooth muscle cells of mouse femoral arteries after wire-induced endothelial denudation. In vitro denudation of monolayers of human umbilical vein ECs also leads to an increase in ALK1. Interestingly, a key factor in tissue remodeling, Krüppel-like factor 6 (KLF6) translocates to the cell nucleus during wound healing, concomitantly with an increase in the ALK1 gene transcriptional rate. KLF6 knock down in human umbilical vein ECs promotes ALK1 mRNA downregulation. Moreover, Klf6(+/-) mice have lower levels of Alk1 in their vasculature compared with their wild-type siblings. Chromatin immunoprecipitation assays show that KLF6 interacts with ALK1 promoter in ECs, and this interaction is enhanced during wound healing. We demonstrate that KLF6 is transactivating ALK1 gene, and this transactivation occurs by a synergistic cooperative mechanism with specificity protein 1. Finally, Alk1 levels in vascular smooth muscle cells are not directly upregulated in response to damage, but in response to soluble factors, such as interleukin 6, released from ECs after injury. CONCLUSIONS: ALK1 is upregulated in ECs during vascular injury by a synergistic cooperative mechanism between KLF6 and specificity protein 1, and in vascular smooth muscle cells by an EC-vascular smooth muscle cell paracrine communication during vascular remodeling.This work was supported by the Ministerio de Ciencia e Innovación of Spain (MICINN grants SAF2007-61827 and SAF2010-19222 to C.B. and SAF2008-01218 to L.M.B., and predoctoral fellowship BES-2005–7974 to E.M.G-M), Genoma España (MEICA), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Red HERACLES (RD6/009/0008 to M.R.), and National Institutes of Health & National Center for Research Resources (DK56621 and DK37340 to S.L.F.).Peer reviewe