Scientific Reports (Mar 2023)

Differential toxicity profile of secreted and processed α-Klotho expression over mineral metabolism and bone microstructure

  • Joan Roig-Soriano,
  • Cristina Sánchez-de-Diego,
  • Jon Esandi-Jauregui,
  • Sergi Verdés,
  • Carmela R. Abraham,
  • Assumpció Bosch,
  • Francesc Ventura,
  • Miguel Chillón

DOI
https://doi.org/10.1038/s41598-023-31117-6
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 10

Abstract

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Abstract The aging-protective gene α-Klotho (KL) produces two main transcripts. The full-length mRNA generates a transmembrane protein that after proteolytic ectodomain shedding can be detected in serum as processed Klotho (p-KL), and a shorter transcript which codes for a putatively secreted protein (s-KL). Both isoforms exhibit potent pleiotropic beneficial properties, although previous reports showed negative side effects on mineral homeostasis after increasing p-KL concentration exogenously. Here, we expressed independently both isoforms using gene transfer vectors, to assess s-KL effects on mineral metabolism. While mice treated with p-KL presented altered expression of several kidney ion channels, as well as altered levels of Pi and Ca2+ in blood, s-KL treated mice had levels comparable to Null-treated control mice. Besides, bone gene expression of Fgf23 showed a fourfold increase after p-KL treatment, effects not observed with the s-KL isoform. Similarly, bone microstructure parameters of p-KL-treated mice were significantly worse than in control animals, while this was not observed for s-KL, which showed an unexpected increase in trabecular thickness and cortical mineral density. As a conclusion, s-KL (but not p-KL) is a safe therapeutic strategy to exploit KL anti-aging protective effects, presenting no apparent negative effects over mineral metabolism and bone microstructure.