title: Human mesenchymal stem cells and derived extracellular vesicles induce regulatory dendritic cells in type 1 diabetic patients.
abstract: OBJECTIVE
  Mesenchymal stem cells (MSCs) can exert an immunosuppressive effect on any component of the immune system, including dendritic cells (DCs), by direct contact, the release of soluble markers and extracellular vesicles (EVs). We evaluated whether MSCs and MSC-derived EVs have an immunomodulatory effect on monocyte-derived DCs in type 1 diabetes.
  
  
  METHODS
  Bone marrow derived MSCs were characterised and EVs were obtained by ultracentrifugation. DCs were differentiated from CD14(+) cells, obtained from nine type 1 diabetic patients at disease onset, pulsed with antigen GAD65 and cultured with MSCs or EVs. Levels of DC maturation and activation markers were evaluated by flow cytometry. GAD65-pulsed DCs and autologous CD14(-) cell were co-cultured and IFN-γ enzyme-linked immunosorbent spot responses were assayed. Secreted cytokine levels were measured and Th17 and regulatory T cells were analysed.
  
  
  RESULTS
  MSC- and EV-conditioned DCs acquired an immature phenotype with reduced levels of activation markers and increased IL-10 and IL-6 production. Conditioned DC plus T cell co-cultures showed significantly decreased IFN-γ spots and secretion levels. Moreover, higher levels of TGF-β, IL-10 and IL-6 were detected compared with unconditioned DC plus T cell co-cultures. Conditioned DCs decreased Th17 cell numbers and IL-17 levels, and increased FOXP3(+) regulatory T cell numbers. EVs were internalised by DCs and EV-conditioned DCs exhibited a similar effect.
  
  
  CONCLUSIONS
  In type 1 diabetes, MSCs induce immature IL-10-secreting DCs in vitro, thus potentially intercepting the priming and amplification of autoreactive T cells in tissue inflammation. These DCs can contribute to the inhibition of inflammatory T cell responses to islet antigens and the promotion of the anti-inflammatory, regulatory responses exerted by MSCs.
authors.affiliation: Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Favaro
authors.affiliation: Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Carpanetto
authors.affiliation: Immunogenetic and Transplant Biology Laboratory, University of Turin, Turin, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Caorsi
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy.
authors.forename: Mirella
authors.initials: M
authors.lastname: Giovarelli
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy.
authors.forename: Costanza
authors.initials: C
authors.lastname: Angelini
authors.affiliation: Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cavallo-Perin
authors.affiliation: Translational Centre for Regenerative Medicine, University of Turin, Turin, Italy.|Medical Board, Fresenius Medical Care, Bad Homburg, Germany.
authors.forename: Ciro
authors.initials: C
authors.lastname: Tetta
authors.affiliation: Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camussi
authors.affiliation: Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126, Torino, Italy. mariamaddalena.zanone@unito.it.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Zanone
mesh_terms: D000328:Adult; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000473:pathology / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology / Q000503:physiopathology; D000067128:Extracellular Vesicles / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000502:physiology* / Q000648:ultrastructure*; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000502:physiology; D058504:Th17 Cells / Q000166:cytology / Q000502:physiology; D055815:Young Adult
keywords: Cytokines; Dendritic cells; Extracellular vesicles; GAD; Mesenchymal stem cells; Prostaglandin E2; T cells; Type 1 diabetes