Regulation of human mesenchymal stem cell functions by an autocrine loop involving NAD + release and P2Y11-mediated signaling

Floriana Fruscione, Sonia Scarfì, Chiara Ferraris, Santina Bruzzone, Federica Benvenuto, Lucrezia Guida, Antonio Uccelli, Annalisa Salis, Cesare Usai, Emanuela Jacchetti, Cristina Ilengo, Silvia Scaglione, Rodolfo Quarto, Elena Zocchi, Antonio De Flora

Research output: Contribution to journalArticlepeer-review


In several cell types, a regulated efflux of NAD + across Connexin 43 hemichannels (Cx43 HC) can occur, and extracellular NAD + (NAD + e) affects cell-specific functions. We studied the capability of bone marrow-derived human mesenchymal stem cells (MSC) to release intracellular NAD + through Cx43 HC. NAD + efflux, quantified by a sensitive enzymatic cycling assay, was significantly upregulated by low extracellular Ca 2+ (5-6-fold), by shear stress (13-fold), and by inflammatory conditions (3.1- and 2.5-fold in cells incubated with lipopolysaccharide (LPS) or at 39°C, respectively), as compared with untreated cells, whereas it was downregulated in Cx43-siRNA-transfected MSC (by 53%) and by cell-to-cell contact (by 45%). Further, we show that NAD + e activates the purinergic receptor P2Y 11 and a cyclic adenosin monophosphate (cAMP)/cyclic ADP-ribose/[Ca 2+] i signaling cascade, involving the opening, unique to MSC, of L-type Ca 2+ channels. Extracellular NAD + enhanced nuclear translocation of cAMP/Ca 2+-dependent transcription factors. Moreover, NAD +, either extracellularly added or autocrinally released, resulted in stimulation of MSC functions, including proliferation, migration, release of prostaglandin E 2 and cytokines, and downregulation of T lymphocyte proliferation compared with controls. No detectable modifications of MSC markers and of adipocyte or osteocyte differentiation were induced by NAD + e. Controls included Cx43-siRNA transfected and/or NAD +-glycohydrolase-treated MSC (autocrine effects), and NAD +-untreated or P2Y 11-siRNA-transfected MSC (exogenous NAD +). These findings suggest a potential beneficial role of NAD + e in modulating MSC functions relevant to MSC-based cell therapies.

Original languageEnglish
Pages (from-to)1183-1198
Number of pages16
JournalStem Cells and Development
Issue number7
Publication statusPublished - Jul 1 2011

ASJC Scopus subject areas

  • Cell Biology
  • Developmental Biology
  • Hematology


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