Ponencia
GAD-67 and GAD-65 co-expression in murine Mesenchymal Stem Cells increases their immunosuppressive properties in vitro
Autor
Urrutia, Mariana
Vasquez, Manuel
Rojas, Patricio
Rubilar, Génesi
González, Marisol
Vilches, Rodrigo
Figueroa, Fernando
Rojas, Patricio
Fuentealba-Alday, Rodrigo Esteban
Institución
Resumen
potent anti-inflammatory molecule that inhibits: (1) T-cell proliferation in vitro, (2) the
secretion of pro-inflammatory cytokines by activated macrophages, and (3) antigen
presenting cells function. GABA is synthesized from glutamic acid by glutamic acid
decarboxylase (GAD). In mammals, there are two isoforms, GAD-67 and GAD-65, which
differ in molecular weight, subcellular localization and cofactor requirements.
Mesenchymal Stem Cells (MSC) are multipotent cells that show strong
immunosuppressive properties after inflammatory environment sensing. Our previous
results demonstrate that IFN-γ and IL-1β pro-inflammatory cytokines selectively increase
GAD-67 mRNA and protein levels, and enhances MSC immunosuppression activity in
vitro. We hypothesize that GABA synthesis is an effector mechanism for MSCmediated
immunosuppression. Here, we analyzed the effect of GAD-67 and GAD-65
overexpression in the immunosuppressive properties of murine MSC. We prepared GAD
constructs, established an electroporation protocol for MSC transfection, and measured
CD4+ T-cell proliferation in co-culture experiments with transfected MSCs to assess
immunosuppression. Only co-expression of GAD-67 and GAD-65 increased the
immunosuppressive properties of MSC. Our results demonstrate that GAD
overexpression increases MSC-mediated immunosuppression, and suggest an important
role for GAD-65 in this activity. GABA secretion through GAD-67/GAD-65 overexpression
might be useful to modulate immunosuppressive properties of MSC.