title: Synthesis of 1,25-dihydroxyvitamin D(3) by human endothelial cells is regulated by inflammatory cytokines: a novel autocrine determinant of vascular cell adhesion.
abstract: In addition to its calciotropic function, the secosteroid 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) has potent nonclassical effects. In particular, local production of 1,25D(3) catalyzed by the enzyme 1alpha-hydroxylase (1alpha-OHase) may act as an autocrine/paracrine immunomodulatory mechanism. To investigate the significance of this in vascular tissue the expression and function of 1alpha-OHase in human endothelial cells was characterized. Immunohistochemical and in situ hybridization analyses show, for the first time, the presence of 1alpha-OHase mRNA and protein in endothelial cells from human renal arteries as well as postcapillary venules from lymphoid tissue. Reverse transcription-PCR and Western blot analyses confirmed the presence of 1alpha-OHase in primary cultures of human umbilical vein endothelial cells (HUVEC). Enzyme activity in HUVEC (318 +/- 56 fmoles 1,25(OH)(2)D(3)/hr/mg protein) increased after treatment with tumor necrosis factor-alpha (1054 +/- 166, P < 0.01), lipopolysaccharide (1381 +/- 88, P < 0.01), or forskolin (554 +/- 56, P < 0.05). Functional studies showed that exogenously added 1,25(OH)(2)D(3) or its precursor, 25-hydroxyvitamin D(3) (25(OH)D(3)), significantly decreased HUVEC proliferation after 72 h of treatment (33% and 11%, respectively). In addition, after 24 h treatment, both 1,25(OH)(2)D(3) and 25(OH)D(3) increased the adhesion of monocytic U937 cells to HUVEC (159% and 153%, respectively). These data indicate that human endothelia are able to produce active vitamin D. The rapid induction of endothelial 1alpha-OHase activity by inflammatory cytokines suggests a novel autocrine/paracrine role for the enzyme, possibly as a modulator of endothelial cell adhesion.
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Zehnder
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Bland
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Ravinder S
authors.initials: RS
authors.lastname: Chana
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: David C
authors.initials: DC
authors.lastname: Wheeler
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Howie
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Williams
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Stewart
authors.affiliation: *Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham; and Centre for Nephrology, Royal Free and University College Medical School, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Hewison
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D019898:Autocrine Communication; D002112:Calcifediol / Q000494:pharmacology; D002117:Calcitriol / Q000096:biosynthesis* / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D016207:Cytokines / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D018836:Inflammation Mediators / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D005576:Colforsin; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol; D002112:Calcifediol