RESUMEN
Diabetes poses a substantial burden to society as it can lead to serious complications and premature death. The number of cases continues to increase worldwide. Two major causes of diabetes are insulin resistance and insulin insufficiency. Currently, there are few antidiabetic drugs available that can preserve or protect ß-cell function to overcome insulin insufficiency in diabetes. We describe a therapeutic strategy to preserve ß-cell function by overexpression of follistatin (FST) using an AAV vector (AAV8-Ins-FST) in diabetic mouse model. Overexpression of FST in the pancreas of db/db mouse increased ß-cell islet mass, decreased fasting glucose level, alleviated diabetic symptoms, and essentially doubled lifespan of the treated mice. The observed islet enlargement was attributed to ß-cell proliferation as a result of bioneutralization of myostatin and activin by FST. Overall, our study indicates overexpression of FST in the diabetic pancreas preserves ß-cell function by promoting ß-cell proliferation, opening up a new therapeutic avenue for the treatment of diabetes.
Asunto(s)
Folistatina/genética , Expresión Génica , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Animales , Biomarcadores , Proliferación Celular , Dependovirus/clasificación , Dependovirus/genética , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/terapia , Modelos Animales de Enfermedad , Folistatina/metabolismo , Terapia Genética , Vectores Genéticos/administración & dosificación , Vectores Genéticos/genética , Humanos , Inmunohistoquímica , Insulina/sangre , Islotes Pancreáticos/anatomía & histología , Islotes Pancreáticos/metabolismo , Ligandos , Masculino , Ratones , Fenotipo , Fosfatidilinositol 3-Quinasas/metabolismo , Unión Proteica , Proteínas Proto-Oncogénicas c-akt/metabolismo , Serogrupo , Transducción de Señal , Proteínas Smad/metabolismo , Transducción Genética , TransgenesRESUMEN
Mutations in fukutin-related protein (FKRP) gene cause a wide spectrum of disease phenotypes including the mild limb-girdle muscular dystrophy 2I (LGMD2I), the severe Walker-Warburg syndrome, and muscle-eye-brain disease. FKRP deficiency results in α-dystroglycan (α-DG) hypoglycosylation in the muscle and heart, which is a biochemical hallmark of dystroglycanopathies. To study gene replacement therapy, we generated and characterized a new mouse model of LGMD2I harboring the human mutation leucine 276 to isoleucine (L276I) in the mouse alleles. The homozygous knock-in mice (L276I(KI)) mimic the classic late onset phenotype of LGMD2I in both skeletal and cardiac muscles. Systemic delivery of human FKRP gene by AAV9 vector in the L276I(KI) mice, at either neonatal age or at the age of 9 months, rendered body wide FKRP expression and restored glycosylation of α-DG in both skeletal and cardiac muscles. FKRP gene therapy ameliorated dystrophic pathology and cardiomyopathy such as muscle degeneration, fibrosis, and myofiber membrane leakage, resulting in restoration of muscle and heart contractile functions. Thus, these results demonstrated that the treatment based on FKRP gene replacement was effective.
