Spironolactone ameliorates PIT1-dependent vascular osteoinduction in klotho-hypomorphic mice
Jakob Voelkl, … , Makoto Kuro-o, Florian Lang
Jakob Voelkl, … , Makoto Kuro-o, Florian Lang
Published January 9, 2013
Citation Information: J Clin Invest. 2013;123(2):812-822. https://doi.org/10.1172/JCI64093.
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Research Article

Spironolactone ameliorates PIT1-dependent vascular osteoinduction in klotho-hypomorphic mice

Abstract

Klotho is a potent regulator of 1,25-hydroxyvitamin D3 [1,25(OH)2D3] formation and calcium-phosphate metabolism. Klotho-hypomorphic mice (kl/kl mice) suffer from severe growth deficits, rapid aging, hyperphosphatemia, hyperaldosteronism, and extensive vascular and soft tissue calcification. Sequelae of klotho deficiency are similar to those of end-stage renal disease. We show here that the mineralocorticoid receptor antagonist spironolactone reduced vascular and soft tissue calcification and increased the life span of kl/kl mice, without significant effects on 1,25(OH)2D3, FGF23, calcium, and phosphate plasma concentrations. Spironolactone also reduced the expression of osteoinductive Pit1 and Tnfa mRNA, osteogenic transcription factors, and alkaline phosphatase (Alpl) in calcified tissues of kl/kl mice. In human aortic smooth muscle cells (HAoSMCs), aldosterone dose-dependently increased PIT1 mRNA expression, an effect paralleled by increased expression of osteogenic transcription factors and enhanced ALP activity. The effects of aldosterone were reversed by both spironolactone treatment and PIT1 silencing and were mitigated by FGF23 cotreatment in HAoSMCs. In conclusion, aldosterone contributes to vascular and soft tissue calcification, an effect due, at least in part, to stimulation of spironolactone-sensitive, PIT1-dependent osteoinductive signaling.

Authors

Jakob Voelkl, Ioana Alesutan, Christina B. Leibrock, Leticia Quintanilla-Martinez, Volker Kuhn, Martina Feger, Sobuj Mia, Mohamed S.E. Ahmed, Kevin P. Rosenblatt, Makoto Kuro-o, Florian Lang

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Figure 5

Influence of spironolactone treatment on renal osteoinductive signaling in kl/kl mice.

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Influence of spironolactone treatment on renal osteoinductive signaling ...
Arithmetic mean ± SEM (n = 7–8; arbitrary units) of mRNA levels encoding (A) Tnfa, (B) Msx2, (C) Cbfa1, and (D) Osx in renal tissue of WT mice (white bars) and kl/kl mice (black bars), treated with control solution or spironolactone. #P < 0.05, ##P < 0.01, compared with kl/kl mice; **P < 0.01, ***P < 0.001, compared with WT control-treated mice. (E) Immunohistochemical analysis and confocal microscopy (original magnification, ×400) of Cbfa1 and osterix expression in renal tissue of WT mice, kl/kl mice, and kl/kl mice treated with spironolactone. Osteoblastic marker expression is represented by green labeling, nuclei are labeled in blue, and actin staining is labeled in red. Scale bar: 20 μm.