title: In vivo production of novel vitamin D2 hydroxy-derivatives by human placentas, epidermal keratinocytes, Caco-2 colon cells and the adrenal gland.
abstract: We investigated the metabolism of vitamin D2 to hydroxyvitamin D2 metabolites ((OH)D2) by human placentas ex-utero, adrenal glands ex-vivo and cultured human epidermal keratinocytes and colonic Caco-2 cells, and identified 20(OH)D2, 17,20(OH)₂D2, 1,20(OH)₂D2, 25(OH)D2 and 1,25(OH)₂D2 as products. Inhibition of product formation by 22R-hydroxycholesterol indicated involvement of CYP11A1 in 20- and 17-hydroxylation of vitamin D2, while use of ketoconazole indicated involvement of CYP27B1 in 1α-hydroxylation of products. Studies with purified human CYP11A1 confirmed the ability of this enzyme to convert vitamin D2 to 20(OH)D2 and 17,20(OH)₂D2. In placentas and Caco-2 cells, production of 20(OH)D2 was higher than 25(OH)D2 while in human keratinocytes the production of 20(OH)D2 and 25(OH)D2 were comparable. HaCaT keratinocytes showed high accumulation of 1,20(OH)₂D2 relative to 20(OH)D2 indicating substantial CYP27B1 activity. This is the first in vivo evidence for a novel pathway of vitamin D2 metabolism initiated by CYP11A1 and modified by CYP27B1, with the product profile showing tissue- and cell-type specificity.
authors.affiliation: Department of Pathology and Medicine, University of Tennessee HSC, Memphis, TN, USA; Division of Rheumatology and Connective Tissue Diseases of the Department of Medicine, University of Tennessee HSC, Memphis, TN, USA. Electronic address: aslominski@uthsc.edu.
authors.forename: Andrzej T
authors.initials: AT
authors.lastname: Slominski
authors.affiliation: Department of Pathology and Medicine, University of Tennessee HSC, Memphis, TN, USA.
authors.forename: Tae-Kang
authors.initials: TK
authors.lastname: Kim
authors.affiliation: School of Pharmacy, CHIRI-Biosciences, Curtin University, WA, Australia.
authors.forename: Haleem Z
authors.initials: HZ
authors.lastname: Shehabi
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA, Australia.
authors.forename: Edith K Y
authors.initials: EK
authors.lastname: Tang
authors.affiliation: School of Pharmacy, CHIRI-Biosciences, Curtin University, WA, Australia.
authors.forename: Heather A E
authors.initials: HA
authors.lastname: Benson
authors.affiliation: Department of Biochemistry, Belarusian State University, Minsk, Belarus.
authors.forename: Igor
authors.initials: I
authors.lastname: Semak
authors.affiliation: Pharmaceutical Sciences, University of Tennessee HSC, Memphis, TN, USA.
authors.forename: Zongtao
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Pharmaceutical Sciences, University of Tennessee HSC, Memphis, TN, USA.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Yates
authors.affiliation: Pharmaceutical Sciences, University of Tennessee HSC, Memphis, TN, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Pharmaceutical Sciences, University of Tennessee HSC, Memphis, TN, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA, Australia. Electronic address: robert.tuckey@uwa.edu.au.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Tuckey
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D018938:Caco-2 Cells; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism*; D004872:Ergocalciferols / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D006888:Hydroxycholesterols / Q000494:pharmacology; D006900:Hydroxylation; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007654:Ketoconazole / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009928:Organ Specificity; D010920:Placenta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D046509:Tissue Culture Techniques
chemical_list: D004872:Ergocalciferols; D006888:Hydroxycholesterols; D011994:Recombinant Proteins; C003585:22-hydroxycholesterol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme; D007654:Ketoconazole
keywords: 20-Hydroxyvitmin D2; Adrenals; CYP11A1; Keratinocytes; Placenta; Vitamin D