title: Osteogenic differentiation of human MSCs: Specific occupancy of the mitochondrial DNA by NFATc1 transcription factor.
abstract: A substantial body of evidence indicates that mitochondrial morphology and function change during osteogenic differentiation. However, molecular mechanisms linking mitochondrial dynamics with the regulation of osteoblast functions are poorly understood. Amongst the molecules that influence the decision of human mesenchymal stem cells (hMSCs) to become osteoblasts are Slug and NFATc1 transcription factors (TFs). These molecules also interfere with different mitochondria-dependent pathways in response to a variety of cellular demands. The present study investigated the recruitment of Slug and NFATc1 at the D-loop regulatory region of mitochondrial DNA (mtDNA) in osteogenic differentiated hMSCs with the aim of exploring whether Slug and NFATc1 also act as mitoTFs in the mitochondrial pool of nuclear TFs. The results demonstrate that NFATc1, but not Slug, is localized in the mitochondria. Using chromatin immunoprecipitation assay, we found that NFATc1 is recruited at mtDNA, but this occurs only when the calcification process is at its highest in osteo-induced MSC and the maximum level of differentiation is reached. Occupancy of the mtDNA by NFATc1 is associated with a decreased expression of crucial mitochondrial genes such as Cytochrome B and NADH dehydrogenase 1. This suggests that NFATc1 acts as a negative regulator of mtDNA transcription during the calcification process and interruption of aerobic energy demand. The finding of NFATc1 participation in osteogenic differentiation through its direct involvement in the regulatory machinery of mitochondria suggests a new role for this TF and adds information on communication between mitochondrial and nuclear genomes.
authors.affiliation: Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Lambertini
authors.affiliation: Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Penolazzi
authors.affiliation: Section of Pathology Oncology, Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery, Experimental Medicine, University of Ferrara, Ferrara, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Morganti
authors.affiliation: Laboratorio di Immunoreumatologia e Rigenerazione Tissutale, IOR, Bologna, Italy.
authors.forename: Gina
authors.initials: G
authors.lastname: Lisignoli
authors.affiliation: CNR - National Research Council of Italy, Institute of Molecular Genetics, Bologna, Italy; Laboratory of Musculoskeletal Cell Biology, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Zini
authors.affiliation: Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Angelozzi
authors.affiliation: Section of Pathology Oncology, Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery, Experimental Medicine, University of Ferrara, Ferrara, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bonora
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Ferroni
authors.affiliation: Section of Pathology Oncology, Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery, Experimental Medicine, University of Ferrara, Ferrara, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pinton
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zavan
authors.affiliation: Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy. Electronic address: piv@unife.it.
authors.forename: Roberta
authors.initials: R
authors.lastname: Piva
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors / Q000378:metabolism*; D010012:Osteogenesis; D011485:Protein Binding
chemical_list: D004272:DNA, Mitochondrial; D050778:NFATC Transcription Factors; C494003:NFATC1 protein, human
keywords: Chromatin immunoprecipitation assay; Mesenchymal stem cells; Mitochondria; NFATc1; Osteogenic differentiation