Msx2 promotes cardiovascular calcification by activating paracrine Wnt signals.
In diabetic LDLR-/- mice, an ectopic BMP2-Msx2 gene regulatory program is upregulated in association with vascular calcification. We verified the procalcific actions of aortic Msx2 expression in vivo. CMV-Msx2 transgenic (CMV-Msx2Tg(+)) mice expressed 3-fold higher levels of aortic Msx2 than nontransgenic littermates. On high-fat diets, CMV-Msx2Tg(+) mice exhibited marked cardiovascular calcification involving aortic and coronary tunica media. This corresponded to regions of Msx2 immunoreactivity in adjacent adventitial myofibroblasts, suggesting a potential paracrine osteogenic signal. To better understand Msx2-regulated calcification, we studied actions in 10T1/2 cells. We found that conditioned media from Msx2-transduced 10T1/2 cells (Msx2-CM) is both pro-osteogenic and adipostatic; these features are characteristic of Wnt signaling. Msx2-CM stimulated Wnt-dependent TCF/LEF transcription, and Msx2-transduced cells exhibited increased nuclear beta-catenin localization with concomitant alkaline phosphatase induction. Msx2 upregulated Wnt3a and Wnt7a but downregulated expression of the canonical inhibitor Dkk1. Dkk1 treatment reversed osteogenic and adipostatic actions of Msx2. Teriparatide, a PTH1R agonist that inhibits murine vascular calcification, suppressed vascular BMP2-Msx2-Wnt signaling. Analyses of CMV-Msx2Tg(+) mice confirmed that Msx2 suppresses aortic Dkk1 and upregulates vascular Wnts; moreover, TOPGAL(+) (Wnt reporter); CMV-Msx2Tg(+) mice exhibited augmented aortic LacZ expression. Thus, Msx2-expressing cells elaborated an osteogenic milieu that promotes vascular calcification in part via paracrine Wnt signals.
Shao
Jian-Su
JS
Department of Medicine, Division of Bone and Mineral Diseases, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Cheng
Su-Li
SL
Pingsterhaus
Joyce M
JM
Charlton-Kachigian
Nichole
N
Loewy
Arleen P
AP
Towler
Dwight A
DA
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002114:Calcinosis / Q000378:metabolism*; D002319:Cardiovascular System / Q000378:metabolism*; D017077:Culture Media, Conditioned; D003587:Cytomegalovirus; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005822:Genetic Vectors; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D050356:Lipid Metabolism; D051379:Mice; D008822:Mice, Transgenic; D019899:Paracrine Communication / Q000502:physiology*; D015534:Trans-Activators / Q000378:metabolism; D051153:Wnt Proteins; D051176:beta Catenin
C495267:CTNNB1 protein, mouse; D017077:Culture Media, Conditioned; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; C084119:MSX2 protein; D015534:Trans-Activators; D051153:Wnt Proteins; D051176:beta Catenin; D000469:Alkaline Phosphatase