title: Calcitriol-modulated human antibiotics: New pathophysiological aspects of vitamin D.
abstract: Traditionally, calcitriol has been considered a calcium and phosphate regulating hormone, but has recently been shown to play a pivotal role in innate immunity. Many barrier and immune cells have membrane and intracellular receptors that recognize different microbial antigens. Activation of these receptors induces synthesis of 1α-hydroxylase, which acts on 25 hydroxyvitamin D to generate intracellular calcitriol. Calcitriol activates its receptor and enhances the synthesis of important human antibiotics like cathelicidin and β2-defensin while inhibiting hepcidin. These pluripotent peptides have an important role in innate immunity, and their regulation is abnormal in hypovitaminosis D. The literature on their secretion mechanisms, levels in different organic fluids, mechanism of action, and relationship with vitamin D is reviewed here.
authors.affiliation: Servicio de Neumología, Hospital Universitario Marqués de Valdecilla, IDIVAL, Universidad de Cantabria, Santander, España. Electronic address: camado@humv.es.
authors.forename: Carlos Antonio
authors.initials: CA
authors.lastname: Amado Diago
authors.affiliation: Servicio de Bioquímica Clínica, Hospital Universitario Marqués de Valdecilla, IDIVAL, Universidad de Cantabria, Santander, España.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: García-Unzueta
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital Universitario Marqués de Valdecilla, IDIVAL, Universidad de Cantabria, Santander, España.
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Fariñas
authors.affiliation: Servicio de Endocrinología y Nutrición, Hospital Universitario Marqués de Valdecilla, IDIVAL, Universidad de Cantabria, Santander, España.
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Amado
mesh_terms: D002117:Calcitriol / Q000494:pharmacology*; D054804:Cathelicidins / Q000096:biosynthesis*; D064451:Hepcidins / Q000037:antagonists & inhibitors; D006801:Humans; D007113:Immunity, Innate; D018167:Receptors, Calcitriol / Q000378:metabolism; D014807:Vitamin D / Q000494:pharmacology*; D014815:Vitamins / Q000494:pharmacology; D023083:beta-Defensins / Q000096:biosynthesis*
chemical_list: D054804:Cathelicidins; C106641:DEFB4A protein, human; D064451:Hepcidins; D018167:Receptors, Calcitriol; D014815:Vitamins; D023083:beta-Defensins; D014807:Vitamin D; D002117:Calcitriol
keywords: Calcitriol; Catelicidina; Cathelicidin; Defensin; Defensina; Hepcidin; Hepcidina; Vitamin D; Vitamina D