title: Adenosine A1 receptor stimulation enhances osteogenic differentiation of human dental pulp-derived mesenchymal stem cells via WNT signaling.
abstract: In this study, mesenchymal stem cells deriving from dental pulp (DPSCs) of normal human impacted third molars, previously characterized for their ability to differentiate into osteoblasts, were used. We observed that: i) DPSCs, undifferentiated or submitted to osteogenic differentiation, express all four subtypes of adenosine receptors (AR) and CD73, corresponding to 5'-ecto-nucleotidase; and ii) AR stimulation with selective agonists elicited a greater osteogenic cell differentiation consequent to A1 receptor (A1R) activation. Therefore, we focused on the activity of this AR. The addition of 15-60nM 2-chloro-N(6)-cyclopentyl-adenosine (CCPA), A1R agonist, to DPSCs at each change of the culture medium significantly increased the proliferation of cells grown in osteogenic medium after 8days in vitro (DIV) without modifying that of undifferentiated DPSCs. Better characterizing the effect of A1R stimulation on the osteogenic differentiation capability of these cells, we found that CCPA increased the: i) expression of two well known and early osteogenic markers, RUNX-2 and alkaline phosphatase (ALP), after 3 and 7DIV; ii) ALP enzyme activity at 7DIV and iii) mineralization of extracellular matrix after 21DIV. These effects, abolished by cell pre-treatment with the A1R antagonist 8-cyclopentyl-1,3-dipropyl-xanthine (DPCPX), involved the activation of the canonical Wnt signaling as, in differentiating DPSCs, CCPA significantly increased dishevelled protein and inhibited glycogen synthase kinase-3β, both molecules being downstream of Wnt receptor signal pathway. Either siRNA of dishevelled or cell pre-treatment with Dickkopf-1, known inhibitor of Wnt signaling substantially reduced either DPSC osteogenic differentiation or its enhancement promoted by CCPA. Summarizing, our findings indicate that the stimulation of A1R may stimulate DPSC duplication enhancing their osteogenic differentiation efficiency. These effects may have clinical implications possibly facilitating bone tissue repair and remodeling.
authors: Department of Experimental and Clinical Sciences, University of Chieti-Pescara, Chieti, Italy; Stem Tech Group, Chieti, Italy.
authors: Iolanda
authors: I
authors: D'Alimonte
authors: Eleonora
authors: E
authors: Nargi
authors: Angela
authors: A
authors: Lannutti
authors: Marco
authors: M
authors: Marchisio
authors: Laura
authors: L
authors: Pierdomenico
authors: Giovanni
authors: G
authors: Costanzo
authors: Patrizia
authors: P
authors: Di Iorio
authors: Patrizia
authors: P
authors: Ballerini
authors: Patricia
authors: P
authors: Giuliani
authors: Francesco
authors: F
authors: Caciagli
authors: Renata
authors: R
authors: Ciccarelli
mesh_terms: D015720:5'-Nucleotidase / Q000096:biosynthesis; D000293:Adolescent; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D003782:Dental Pulp / Q000166:cytology* / Q000378:metabolism; D005260:Female; D058851:GPI-Linked Proteins / Q000096:biosynthesis; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D043682:Receptor, Adenosine A1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D058851:GPI-Linked Proteins; D043682:Receptor, Adenosine A1; D015720:5'-Nucleotidase; C548241:NT5E protein, human