Generación de iPSC como modelo de estudio de enfermedades mitocondriales causadas por mutaciones en GFM1 y POLG

• Autores: Francisco Zurita Diaz
• Directores de la Tesis: María Esther Gallardo (dir. tes.), Rafael Garesse (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2018
• Idioma: español
• Número de páginas: 208
• Tribunal Calificador de la Tesis: José Fernández Piqueras (presid.), Eva María Richard Rodríguez (secret.), Miguel Angel Martín Casanueva (voc.), Carmen Fiuza (voc.), Alejandro Lucía Mulas (voc.)
• Programa de doctorado: Programa de Doctorado en Biociencias Moleculares por la Universidad Autónoma de Madrid
• Materias:
  • Química
    • Bioquímica
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Mitochondrial diseases (MD) constitute a wide range of genetic diseases whose common link is an impairment of the oxidative phosphorylation system (OXPHOS). At this moment, there are no effective treatments available for MD, due in part to the lack of appropriate experimental models. In this sense, induced pluripotent stem cells (iPSC) technology emerges as a promising possibility to study the pathogenic mechanisms involved in MD.

    In this doctoral thesis, iPSC from a healthy individual and two patients suffering from MD caused by GFM1 and POLG nuclear gene mutations have been generated and characterized. GFM1 encodes for the mitochondrial translation elongation factor G1 (EFG1) and POLG for the catalytic subunit of the mitochondrial DNA polymerase.

    Subsequently, iPSC were differentiated into neurons and astrocytes in order to establish in vitro models for both pathologies. In the model harboring mutations in the GFM1 gene a defect in OXPHOS in the neural stem cell lines (NSC) has been found.

    Moreover, high extracellular lactate levels both in NSC and neurons could suggest an increase in the glycolytic pathway to obtain ATP. All these data might point out to an alteration in the mitochondrial respiratory capacity in patient-derived cells, probably caused by low EFG1 protein levels. Likewise, the presence of these mutations hinders the NSC proper differentiation into neurons and astrocytes. On the other hand, the model harboring mutations in the POLG gene showed a diminished activity in some of the electron transport chain complexes in NSC. Besides, higher lactic acid levels and lower mitochondrial DNA copy number have been found in neuron patient-derived cells.

    In summary, the different cell types obtained by differentiation of iPSC lines from both patients mimic, at least partially, some biochemical features related to these MD and validate themselves to be a proper in vitro model for the study of these disorders. Besides, these models could allow, in the near future, the finding of pharmacological targets and the development of a high-throughput drug screening platform.