Nonviral-Mediated Hepatic Expression of IGF-I Increases Treg Levels and Suppresses Autoimmune Diabetes in Mice
- Xavier M. Anguela1,2,3,
- Sabrina Tafuro1,2,3,†,
- Carles Roca1,2,3,
- David Callejas1,2,3,
- Judith Agudo1,2,3,
- Mercè Obach1,3,
- Albert Ribera1,2,3,
- Albert Ruzo1,2,3,
- Christopher J. Mann1,2,3,
- Alba Casellas1,2,3 and
- Fatima Bosch1,2,3⇓
- 1Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain
- 2Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- 3CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
- Corresponding author: Fatima Bosch, .
In type 1 diabetes, loss of tolerance to β-cell antigens results in T-cell-dependent autoimmune destruction of β cells. The abrogation of autoreactive T-cell responses is a prerequisite to achieve long-lasting correction of the disease. The liver has unique immunomodulatory properties and hepatic gene transfer results in tolerance induction and suppression of autoimmune diseases, in part by regulatory T-cell (Treg) activation. Hence, the liver could be manipulated to treat or prevent diabetes onset through expression of key genes. IGF-I may be an immunomodulatory candidate because it prevents autoimmune diabetes when expressed in β cells or subcutaneously injected. Here, we demonstrate that transient, plasmid-derived IGF-I expression in mouse liver suppressed autoimmune diabetes progression. Suppression was associated with decreased islet inflammation and β-cell apoptosis, increased β-cell replication, and normalized β-cell mass. Permanent protection depended on exogenous IGF-I expression in liver nonparenchymal cells and was associated with increased percentage of intrapancreatic Tregs. Importantly, Treg depletion completely abolished IGF-I-mediated protection confirming the therapeutic potential of these cells in autoimmune diabetes. This study demonstrates that a nonviral gene therapy combining the immunological properties of the liver and IGF-I could be beneficial in the treatment of the disease.
- Received December 12, 2011.
- Accepted August 10, 2012.
- © 2012 by the American Diabetes Association.
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