Microenvironment-Dependent MSC Immunoregulation in Type 1 Diabetes: Insights From IFNγ Preconditioning

Abstract

Interferon-gamma (IFNγ) plays a crucial role in the pathogenesis of type 1 diabetes (T1D) and is widely utilized to license mesenchymal stem/stromal cells (MSCs) to enhance their immunosuppressive properties through a process known as preconditioning or priming. This study investigates the interaction of MSCs preconditioned with (IFNγ⁺) or without (IFNγ⁻) IFNγ, with peripheral blood mononuclear cells (PBMCs) from healthy controls (HC) and T1D patients. We assessed the effects of these interactions on anti-inflammatory gene expression, chemokine and receptor profiles, and the induction of regulatory T (Treg) cells. Our findings reveal contrasting responses in HC and T1D PBMCs when exposed to IFNγ⁺ and IFNγ⁻ MSCs, particularly in the expression of key genes such as CXCR3 and its ligands (CXCL9, CXCL10), CXCR6, CCR5, and its ligands (CCL3 and CCL4). Pathway enrichment analysis further showed that IFNγ preconditioning tailors MSC responses to specific immune microenvironments. These differential gene expression patterns were also reflected in the proportions of Treg cells, which varied depending on whether paracrine signaling or direct cell contact was involved. Collectively, our results demonstrate that IFNγ⁺ and IFNγ⁻ MSCs create distinct immunomodulatory microenvironments in T1D PBMCs compared to HC PBMCs, emphasizing the potential for tailored MSC-based therapies in T1D treatment.