Generation of Genetically Modified Rats Using CRISPR/Cas9 Genome-Editing System to Reveal Novel Vitamin D Actions

We previously revealed that the anti-proliferative activity of 25-hydroxyvitamin D3 (25(OH)D3) in human prostate PZ-HPV-7 cells depends on direct action 25(OH)D3 through vitamin D receptor (VDR). then attempted to confirm vivo using Cyp27b1 knockout (KO) mice. Daily administration at 250 μg/kg bw/day rescued rachitic conditions KO The plasma levels calcium, phosphorus, and parathyroid hormonea as well bone mineral density female sexual cycle were normalized via 25(OH)D3. These results strongly suggest However, our surprise, normal 1a,25(OH)2D3 detected mice, probably due Cyp27a1, which has a weak 1a-hydroxylation toward Next, we generated novel system genetically modified (GM) rats deficient or Vdr gene reveal molecular mechanisms action. Human type II rickets model with mutant (R270L), recognizes 1,25(OH)2D3 an affinity equivalent 25(OH)D3, also generated. Cyp27b1-knockout (KO), Vdr-KO, (R270L) showed symptoms rickets, including growth retardation abnormal formation. Among these animals, Cyp27b1-KO had notably low calcium blood most severe retardation, while Vdr-KO skin formation alopecia. Administration restored rats. As shown was synthesized In contrast, effects exerts VDR-genomic pathways. containing three different types GM is useful for elucidating mechanism