title: Potential Role of Activating Transcription Factor 5 during Osteogenesis.
abstract: Human adipose-derived stem cells are an abundant population of stem cells readily isolated from human adipose tissue that can differentiate into connective tissue lineages including bone, cartilage, fat, and muscle. Activating transcription factor 5 is a transcription factor of the ATF/cAMP response element-binding protein (CREB) family. It is transcribed in two types of mRNAs (activating transcription factor 5 isoform 1 and activating transcription factor 5 isoform 2), encoding the same single 30-kDa protein. Although it is well demonstrated that it regulates the proliferation, differentiation, and apoptosis, little is known about its potential role in osteogenic differentiation. The aim of this study was to evaluate the expression levels of the two isoforms and protein during osteogenic differentiation of human adipose-derived stem cells. Our data indicate that activating transcription factor 5 is differentially expressed reaching a peak of expression at the stage of bone mineralization. These findings suggest that activating transcription factor 5 could play an interesting regulatory role during osteogenesis, which would provide a powerful tool to study bone physiology.
authors.affiliation: IOM Ricerca Srl, Via Penninazzo 11, 95029 Viagrande, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Vicari
authors.affiliation: IOM Ricerca Srl, Via Penninazzo 11, 95029 Viagrande, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Calabrese
authors.affiliation: IOM Ricerca Srl, Via Penninazzo 11, 95029 Viagrande, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Forte
authors.affiliation: IOM Ricerca Srl, Via Penninazzo 11, 95029 Viagrande, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Giuffrida
authors.affiliation: Department of Experimental Oncology, Mediterranean Institute of Oncology, Via Penninazzo 7, 95029 Viagrande, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Colarossi
authors.affiliation: Department of Experimental Oncology, Mediterranean Institute of Oncology, Via Penninazzo 7, 95029 Viagrande, Italy.
authors.forename: Nunziatina Laura
authors.initials: NL
authors.lastname: Parrinello
authors.affiliation: IOM Ricerca Srl, Via Penninazzo 11, 95029 Viagrande, Italy; Department of Experimental Oncology, Mediterranean Institute of Oncology, Via Penninazzo 7, 95029 Viagrande, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Memeo