Pluripotency and Immunomodulatory Signatures of Canine Induced Pluripotent Stem Cell-derived Mesenchymal Stromal Cells Are Similar to Harvested Mesenchymal Stromal Cells

Abstract Background: With a view towards harnessing the therapeutic potential of canine mesenchymal stromal cells (cMSCs) as modulators of inflammation and the immune response, and to avoid the issues of the variable quality and quantity of harvested cMSCs, we examined the immunomodulatory properties of cMSCs derived from canine induced pluripotent stem cells (ciMSCs), and compared them to cMSCsharvested from adipose tissue (cAT-MSC) and bone marrow (cBM-MSC).Methods and results: Deep sequencing of the ciMSC transcriptome confirmed that ciMSCsexpress more genes in common with cBM-MSCsthan with the ciPSCs from which they were derived. Both ciMSCs and cBM-MSCsexpress a range of pluripotency factors in common withthe ciPSCsincluding NANOG, POU5F1 (OCT-4), SOX-2, KLF-4, LIN-28A, MYC, LIF, LIFR, and TERT. However, ESRRB and PRDM-14, both factors associated with naïve, rather than primed, pluripotency were expressed only in the ciPSCs. LOXL-2, which is involved in epithelial to mesenchymal transition (EMT), is also expressed in ciMSCs and cBM-MSCs but notciPSCs. ciMSCsconstitutively express the immunomodulatory factors iNOS, GAL-9, TGF-β1, PTGER-2αand VEGF, and the pro-inflammatory mediators COX-2,IL-1βand IL-8.When stimulated with the canine pro-inflammatory cytokines tumor necrosis factor-α (cTNF-α), interferon-γ (cIFN-γ), or a combination of both, ciMSCsupregulated their expression ofIDO,iNOS, GAL-9,HGF, TGF-β1, PTGER-2α, VEGF, COX-2, IL-1β andIL-8.When co-cultured with mitogen-stimulated lymphocytes, ciMSCsdownregulated their expression of iNOS, HGF, TGF-β1andPTGER-2α, while increasing their expression of COX-2, IDO and IL-1β. Conclusions: Taken together, these findings suggest that ciMSCs possess similar immunomodulatory capabilities as harvested cMSCs and support further investigation into the potential use ofciMSCsfor the management of canine immune-mediated and inflammatory disorders.