IFN-? orchestrates mesenchymal stem cell plasticity through the signal transducer and activator of transcription 1 and 3 and mammalian target of rapamycin pathways - 27/09/17
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Abstract |
Background |
Mesenchymal stem cells (MSCs) display a therapeutic plasticity because of their ability to modulate immunity, foster tissue repair, and differentiate into mesodermal cells. IFN-γ has been described to differently affect human mesenchymal stem cell (hMSC) and mouse mesenchymal stem cell (mMSC) immunomodulation and differentiation, depending on the inflammatory milieu.
Objective |
We aimed at dissecting the relevant intracellular pathways through which IFN-γ affects MSC plasticity and the consequence of their manipulation on MSC functions.
Methods |
Modification of relevant IFN-γ–dependent pathways in mMSCs was carried out in vitro through gene silencing or chemical inhibition of key components. Functional outcomes were assessed by means of Western blotting, real-time PCR, differentiation, and proliferation assays on MSCs. The effect on T cells was addressed by T-cell proliferation assays; the effect of mammalian target of rapamycin (mTOR) manipulation in MSCs was studied in vivo in a mouse model of delayed-type hypersensitivity assay. To address whether similar mechanisms are involved also in hMSCs on IFN-γ stimulation, the effect of chemical inhibition on the same intracellular pathways was assessed by means of Western blotting, and the final outcome on immunomodulatory properties was evaluated based on real-time PCR and T-cell proliferation.
Results |
We revealed that in mMSCs IFN-γ–induced immunoregulation is mediated by early phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT3, which is significantly enhanced by an extracellular signal-regulated kinase 1/2–dependent mTOR inhibition, thereby promoting pSTAT1 nuclear translocation. Accordingly, after intracellular mTOR inhibition, MSCs augmented their ability to inhibit T-cell proliferation and control delayed-type hypersensitivity in vivo. Similarly, on mTOR blockade, hMSCs also enhanced their immunoregulatory features. A sustained exposure to IFN-γ led to inhibition of STAT3 activity, which in mMSCs resulted in an impaired proliferation and differentiation.
Conclusion |
These results provide new insights about MSC intracellular pathways affected by IFN-γ, demonstrating that pharmacologic or genetic manipulation of MSCs can enhance their immunomodulatory functions, which could be translated into novel therapeutic approaches.
Le texte complet de cet article est disponible en PDF.Graphical abstract |
Key words : IFN-γ, immunomodulation, T cells, mesenchymal stem cells, mammalian target of rapamycin, signal transducer and activator of transcription 1, signal transducer and activator of transcription 3
Abbreviations used : CUC, DTH, ERK, hMSC, IL-18BP, KD, mMSC, MSC, mTOR, OVA, RHEB, siRNA, STAT
Plan
Supported by grants to A.U. from the Italian Foundation for Multiple Sclerosis (grant MESEMS-FISM 2012/S/4), the Italian Ministry of Health (grant no. 1221276), the Italian Ministry of University and Scientific Research (grant no. 2009JN7SCN_003), and Merck Serono (project MS-Run) and by grants to G.M. from the European Union IDEAS Programme European Research Council Starting Grant “menTORing Tregs” (no. 310496), the Fondazione Italiana Sclerosi Multipla (FISM; no. 2012/R/11), and the ASI (Italian Space Agency; no. 2014-033-R.O). |
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Disclosure of potential conflict of interest: G. Matarese receives grant support from a European Union IDEAS Programme European Research Council Starting Grant, Fondazione Italiana Sclerosi Multipla, and the Italian Space Agency. A. Uccelli receives grant support from the Italian Foundation for Multiple Sclerosis, Italian Ministry of Health, Italian Ministry of University and Scientific Research, and Merck Serono; serves on the board for Biogen, TEVA, Roche, Genzyme, Novartis, and Merck Serono; serves as a consultant for Biogen, TEVA, Roche, Genzyme, Novartis, and Merck Serono; and receives grant support from Novartis, Biogen, and FISM. The rest of the authors declare that they have no relevant conflicts of interest. |
Vol 139 - N° 5
P. 1667-1676 - mai 2017 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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