Msx2 Promotes Cardiovascular Calcification by Activating Paracrine Wnt Signals

J Clin Invest. 2005 May;115(5):1210-20. doi: 10.1172/JCI24140. Epub 2005 Apr 14.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Animals
  • Calcinosis / metabolism*
  • Cardiovascular System / metabolism*
  • Culture Media, Conditioned
  • Cytomegalovirus
  • Cytoskeletal Proteins / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Genetic Vectors
  • Homeodomain Proteins
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Lipid Metabolism
  • Mice
  • Mice, Transgenic
  • Paracrine Communication / physiology*
  • Trans-Activators / metabolism
  • Wnt Proteins
  • beta Catenin

Substances

  • CTNNB1 protein, mouse
  • Culture Media, Conditioned
  • Cytoskeletal Proteins
  • DNA-Binding Proteins
  • Homeodomain Proteins
  • Intercellular Signaling Peptides and Proteins
  • MSX2 protein
  • Trans-Activators
  • Wnt Proteins
  • beta Catenin
  • Alkaline Phosphatase