[HTML][HTML] Msx2 promotes cardiovascular calcification by activating paracrine Wnt signals

JS Shao, SL Cheng, JM Pingsterhaus… - The Journal of …, 2005 - Am Soc Clin Investig
JS Shao, SL Cheng, JM Pingsterhaus, N Charlton-Kachigian, AP Loewy, DA Towler
The Journal of clinical investigation, 2005Am Soc Clin Investig
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 …
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 β-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.
The Journal of Clinical Investigation