Deciphering the impact of diet-induced obesity on cellular reprogramming and pluripotency

• Autores: Tiago Manuel Martins Moreira
• Directores de la Tesis: Miguel Angel Fidalgo Pérez (dir. tes.), Diana Guallar Artal (dir. tes.)
• Lectura: En la Universidade de Santiago de Compostela ( España ) en 2025
• Idioma: inglés
• Tribunal Calificador de la Tesis: Miguel Manzanares Fourcade (presid.), Marta María Varela Rey (secret.), David Landeira Frias (voc.)
• Programa de doctorado: Programa de Doctorado en Medicina Molecular por la Universidad de Santiago de Compostela
• Materias:
  • Ciencias de la vida
    • Biología celular
    • Biología molecular
• Enlaces
  • Tesis en acceso abierto en: MINERVA
• Resumen

  • The world is facing a nutrition crisis, most clearly evidenced by unhealthy eating patterns like diet-induced obesity (DIO). This metabolic disorder is linked to serious health issues, including cardiovascular and liver diseases, type 2 diabetes, and cancer. Research indicates that DIO alters cellular and molecular processes associated with these health problems, underscoring the need to address this crisis from multiple angles, including regenerative medicine. In this context, induced pluripotent stem cells (iPSCs), generated through somatic cell reprogramming (SCR), hold great therapeutic potential for personalized regenerative medicine due to their ability to self-renew indefinitely and differentiate into any cell type within an adult organism. However, much of the research on SCR has focused on fibroblasts from standard dietary conditions due to their easier manipulation and higher reprogramming efficiency. Consequently, the impact of DIO on the safe application of this technology in obese individuals, who might benefit the most from regenerative therapies, remains largely unexplored. In my PhD thesis, we aimed to fill this gap by using ex vivo fibroblasts from both standard and high-fat diet (HFD) mouse models. By employing the classical Yamanaka SCR strategy, which involves the overexpression of the transcription factors OCT4, SOX2, KLF4, and c-MYC (OSKM), our main goal was to assess how DIO-induced molecular changes affect the efficiency and quality of iPSC generation from HFD somatic cells. To this end, we adopted a multidisciplinary approach involving several methods of cell and molecular biology, chemical and genetic interventions, high-throughput omics approaches, and bioinformatics analyses to specifically 1) identify dietary-dependent molecular changes during reprogramming, 2) develop new reprogramming strategies, and 3) explore persistent molecular codes linked to DIO memory in pluripotency. Our findings showed that DIO significantly reduces the efficiency of generating iPSCs and induced neurons, highlighting the negative effects of diet on cellular plasticity. We discovered that DIO alters gene expression and splicing, influencing polyamine metabolism, and that restoring polyamine levels can improve OSKM reprogramming efficiency in HFD-fibroblasts. Although the self-renewal of iPSCs was unaffected by a pro-obesity diet, DIO altered transitions between alternative pluripotent states, potentially affecting differentiation, as explored in the context of their exit from pluripotency into endothelial progenitor cells. Additionally, we identified that gene expression and splicing alterations associated with a pro-obesity diet persist in long-term cultured iPSCs and during differentiation, suggesting that DIO memory may have lasting effects on cellular fate determination and function. Finally, we found that fibroblast-like cells derived from HFD-iPSCs retain obesogenic features and exhibit a shared transcriptomic and metabolic memory with parental HFD-fibroblasts, indicating that DIO memory can persist through cellular reprogramming and differentiation, which may complicate reprogramming strategies for therapeutic applications. In summary, this study sheds light on the long-lasting effects of DIO on induced pluripotency technology, and our findings underscore the intricate interplay between obesity, cellular plasticity, and reprogramming. This offers novel insights to improve reprogramming strategies for future therapeutic applications in the context of obesity and associated diseases.