Journal Article

Mitochondrial Localization of Vitamin D Receptor in Human Platelets and Differentiated Megakaryocytes

Attanasio, Angelo, Gallo, Valentina, Silvagno, Francesca, Pescarmona, Gianpiero, De Vivo, Enrico, Mazzucco, Gianna

2010

Overview

Like other steroid hormones, vitamin D elicits both transcriptional events and rapid non genomic effects. Vitamin D receptor (VDR) localization and mechanisms of VDR-triggered non genomic responses are still controversial. Although anticoagulant effects of vitamin D have been reported and VDR signalling has been characterized in monocytes and vascular cells, nothing is known about VDR expression and functions in human platelets, anucleated fragments of megakaryocytes which are known targets of other steroids. In this study we characterized the expression and cellular localization of VDR in human platelets and in a megakaryocyte lineage. Human platelets and their TPA-differentiated precursors expressed a classical 50 kDa VDR protein, which increased with megakaryocytes maturation. By biochemical fractionation studies we demonstrated the presence of the receptor in the soluble and mitochondrial compartment of human platelets, and the observation was confirmed by immunoelectron microscopy analysis. Similar localization was found in mature megakaryocytes, where besides its classical nuclear localization the receptor was evident as soluble and mitochondria resident protein. The results reported here suggest that megakaryocytopoiesis and platelet activation, which are calcium-dependent events, might be modulated by a mitochondrial non genomic activity of VDR. These data open challenging future studies on VDR physiological role in platelets and more generally in mitochondria.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Analysis / Anticoagulants / Apoptosis / Biochemistry / Biology / Blood & organ donations / Blood platelets / Blood Platelets - metabolism / Bone cancer / Calcium / Cell Biology / Cell Differentiation - drug effects / Cloning / Electrophoresis, Polyacrylamide Gel / Flow Cytometry / Fractionation / Gene expression / Genomics / Hematology/Hematopoiesis / Homeostasis / Hormones / Humans / Immunoelectron microscopy / Leukemia / Localization / Medical research / Megakaryocytes / Megakaryocytes - cytology / Megakaryocytes - metabolism / Metabolism / Microscopy / Mitochondria / Mitochondria - metabolism / Monocytes / Nitric oxide / Physiological aspects / Physiology/Morphogenesis and Cell Biology / Platelets / Polyclonal antibodies / Receptors, Calcitriol - blood / Rodents / Signaling / Steroid hormones / Steroids / Tetradecanoylphorbol Acetate - pharmacology / Transcription / Transcription (Genetics) / Vitamin D / Vitamin D receptors