Novel Vitamin D3 Hydroxymetabolites Require Involvement of the Vitamin D Receptor or Retinoic Acid-Related Orphan Receptors for Their Antifibrogenic Activities in Human Fibroblasts
Zorica Janjetovic,
Shariq Qayyum,
Sivani B. Reddy,
Ewa Podgorska,
S. Gates Scott,
Justyna Szpotan,
Alisa A. Mobley,
Wei Li,
Vijay K. Boda,
Senthilkumar Ravichandran,
Robert C. Tuckey,
Anton M. Jetten,
Andrzej T. Slominski
Affiliations
Zorica Janjetovic
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Shariq Qayyum
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Sivani B. Reddy
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Ewa Podgorska
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
S. Gates Scott
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Justyna Szpotan
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Alisa A. Mobley
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Wei Li
College of Pharmacy, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
Vijay K. Boda
College of Pharmacy, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
Senthilkumar Ravichandran
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
Robert C. Tuckey
School of Molecular Science, The University of Western Australia, Perth 6009, Australia
Anton M. Jetten
Cell Biology Section, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
Andrzej T. Slominski
Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
We investigated multiple signaling pathways activated by CYP11A1-derived vitamin D3 hydroxymetabolites in human skin fibroblasts by assessing the actions of these molecules on their cognate receptors and by investigating the role of CYP27B1 in their biological activities. The actions of 20(OH)D3, 20,23(OH)2D3, 1,20(OH)2D3 and 1,20,23(OH)3D3 were compared to those of classical 1,25(OH)2D3. This was undertaken using wild type (WT) fibroblasts, as well as cells with VDR, RORs, or CYP27B1 genes knocked down with siRNA. Vitamin D3 hydroxymetabolites had an inhibitory effect on the proliferation of WT cells, but this effect was abrogated in cells with silenced VDR or RORs. The collagen expression by WT cells was reduced upon secosteroid treatment. This effect was reversed in cells where VDR or RORs were knocked down where the inhibition of collagen production and the expression of anti-fibrotic genes in response to the hydroxymetabolites was abrogated, along with ablation of their anti-inflammatory action. The knockdown of CYP27B1 did not change the effect of either 20(OH)D3 or 20,23(OH)2D3, indicating that their actions are independent of 1α-hydroxylation. In conclusion, the expression of the VDR and/or RORα/γ receptors in fibroblasts is necessary for the inhibition of both the proliferation and fibrogenic activity of hydroxymetabolites of vitamin D3, while CYP27B1 is not required.
