Anti-ACVR2A (aa 24-133) polyclonal antibody

Objectives: Activin A, a TGF beta family member, circulates in the maternal blood at increasing concentrations throughout gestation during a healthy pregnancy. The circulating concentration of activin A is further increased in pre-eclampsia (PE), a hypertensive disorder of pregnancy that is marked by systemic maternal vascular endothelial cell dysfunction. The effect of increasing activin A concentrations on the maternal vascular endothelium is unknown. The study aim was to investigate the effect of physiological and pathological activin A concentrations observed in normotensive and PE pregnancies respectively, on vascular endothelial cell function. Methods and results: Immunostaining demonstrated the presence of the activin A receptor, ACVR2A, in SGHEC-7 cells used to model the vascular endothelium. SGHEC-7 cells were treated with activin A concentrations representative of concentrations throughout gestation in normotensive (0-10 ng/ml) and PE (50 ng/ml) pregnancies. xCELLigence functional assays revealed that normotensive activin A concentrations increased SGHEC-7 proliferation and migration, which was inhibited by PE concentrations. Additionally, fluorescence based assays showed that PE concentrations increased endothelial permeability. None of the tested activin A concentrations affected cell apoptosis. PE concentrations also resulted in an imbalance of the vasoactive factors eNOS, PTGIS and EDN1, as determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assays. Conclusion: Compared with normotensive activin A concentrations, the higher PE activin A concentrations resulted in abnormal endothelial functions, which may contribute to the systemic maternal vascular endothelial cell dysfunction observed in the disorder. (C) 2015 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

Bone and skeletal muscle mass are highly correlated in mammals, suggesting the existence of common anabolic signaling networks that coordinate the development of these two anatomically adjacent tissues. The activin signaling pathway is an attractive candidate to fulfill such a role. Here, we generated mice with conditional deletion of activin receptor (ACVR) type 2A, ACVR2B, or both, in osteoblasts, to determine the contribution of activin receptor signaling in regulating bone mass. Immunohistochemistry localized ACVR2A and ACVR2B to osteoblasts and osteocytes. Primary osteoblasts expressed activin signaling components, including ACVR2A, ACVR2B, and ACVR1B (ALK4) and demonstrated increased levels of phosphorylated Smad2/3 upon exposure to activin ligands. Osteoblasts lacking ACVR2B did not show significant changes in vitro. However, osteoblasts deficient in ACVR2A exhibited enhanced differentiation indicated by alkaline phosphatase activity, mineral deposition, and transcriptional expression of osterix, osteocalcin, and dentin matrix acidic phosphoprotein 1. To investigate activin signaling in osteoblasts in vivo, we analyzed the skeletal phenotypes of mice lacking these receptors in osteoblasts and osteocytes (osteocalcin-Cre). Similar to the lack of effect in vitro, ACVR2B-deficient mice demonstrated no significant change in any bone parameter. By contrast, mice lacking ACVR2A had significantly increased femoral trabecular bone volume at 6 weeks of age. Moreover, mutant mice lacking both ACVR2A and ACVR2B demonstrated sustained increases in trabecular bone volume, similar to those in ACVR2A single mutants, at 6 and 12 weeks of age. Taken together, these results indicate that activin receptor signaling, predominantly through ACVR2A, directly and negatively regulates bone mass in osteoblasts.