Vitamin D Status of Mice Deficient in Scavenger Receptor Class B Type 1, Cluster Determinant 36 and ATP-Binding Cassette Proteins G5/G8

oleh: Mikis Kiourtzidis, Julia Kühn, Corinna Brandsch, Gabriele I. Stangl

Format: Article
Diterbitkan: MDPI AG 2020-07-01

Deskripsi

Classical lipid transporters are suggested to modulate cellular vitamin D uptake. This study investigated the vitamin D levels in serum and tissues of mice deficient in SR-B1 (Srb1<sup>-/-</sup>), CD36 (Cd36<sup>-/-</sup>) and ABC-G5/G8 (Abcg5/g8<sup>-/-</sup>) and compared them with corresponding wild-type (WT) mice. All mice received triple-deuterated vitamin D<sub>3</sub> (vitamin D<sub>3</sub>-d<sub>3</sub>) for six weeks. All knockout mice vs. WT mice showed specific alterations in their vitamin D concentrations. Srb1<sup>-/-</sup> mice had higher levels of vitamin D<sub>3</sub>-d<sub>3</sub> in the serum, adipose tissue, kidney and heart, whereas liver levels of vitamin D<sub>3</sub>-d<sub>3</sub> remained unaffected. Additionally, Srb1<sup>-/-</sup> mice had lower levels of deuterated 25-hydroxyvitamin D<sub>3</sub> (25(OH)D<sub>3</sub>-d<sub>3</sub>) in the serum, liver and kidney compared to WT mice. In contrast, Cd36<sup>-/-</sup> and WT mice did not differ in the serum and tissue levels of vitamin D<sub>3</sub>-d<sub>3</sub>, but Cd36<sup>-/-</sup> vs. WT mice were characterized by lower levels of 25(OH)D<sub>3</sub>-d<sub>3</sub> in the serum, liver and kidney. Finally, Abcg5/g8<sup>-/-</sup> mice tended to have higher levels of vitamin D<sub>3</sub>-d<sub>3</sub> in the serum and liver. Major alterations in Abcg5/g8<sup>-/-</sup> mice were notably higher levels of 25(OH)D<sub>3</sub>-d<sub>3</sub> in the serum and kidney, accompanied by a higher hepatic mRNA abundance of <i>Cyp27a1</i> hydroxylase. To conclude, the current data emphasize the significant role of lipid transporters in the uptake, tissue distribution and activation of vitamin D.