Nutritional and aging-associated barriers to cell reprogramming

• Autor(a) principal: Dias, Rafaela Monteiro
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/40771
• topic: Cell reprogramming; Nutrient signaling; Cardiomyocytes; Cardiac regeneration; Pluripotency

Cardiovascular diseases rank as the primary global cause of mortality, and there is a pressing need for innovative regenerative techniques. Direct cardiac conversion (DCC), involving the transformation of fibroblasts into induced cardiomyocytes (iCMs) through the forced expression of cardiogenic transcription factors (Mef2c, Gata4, Tbx5 - collectively referred to as MGT), holds significant promise for cardiac regeneration. However, DCC faces challenges in achieving clinical effectiveness due to the presence of various epigenetic barriers that must be overcome. In this study, we aimed to investigate how systemic nutrition influences the effectiveness of ex-vivo transdifferentiation of adult dermal mouse fibroblasts into induced cardiomyocytes (iCMs). For that, we exposed 8-week-old male C57BL/6J mice to three different isocaloric dietary conditions for a duration of 10 weeks: a high-fat diet, a low-fat/high-fructose diet and a control diet. A notable increase in body weight and serum glucose levels was observed in the animals that were on the high-fat diet (HFD). In addition, cytokines such as interleukin 4 (IL-4), interleukin 6 (IL-6) and Tumor Necrosis Factor Alpha (TNFα) show deregulated levels in animals submitted to a low-fat diet (LFD) and HFD. Western blot analysis demonstrated a reduction in acetylated histone H3 marks in ex-vivo fibroblasts derived from animals exposed to the HFD. Our results also revealed that there was a slight increase in cTNT-positive cells when transdifferentiation was performed on fibroblasts from LFD-fed animals. In addition, we have shown that embryonic cells have a higher expression of cardiac genes and a lower expression of fibroblast genes compared to adult cells, regardless the diet. Furthermore, we analysed the impact of systemic nutrition on the reprogramming of fibroblasts into induced pluripotent stem cells (iPSCs), showing that this reprogramming is drastically reduced in cells isolated from animals that were on HFD and LFD diets. Up to this point, our findings indicate that systemic nutrients can influence the chromatin marks and plasticity of fibroblast cells, which can be exploited for cardiac regeneration.