Regulação e ativação das células satélites durante a regeneração muscular / Regulation and activation of satellite cells during musculoskeletal regeneration

Os avanços da biologia molecular, biologia celular e genética tem melhorado muito a nossa compreensão da biologia do músculo esquelético, demonstrando que as características biológicas das células satélites (CSs) são fundamentais no processo de regeneração muscular. O potencial terapêutico destas células vem sendo discutido pela literatura, por isso o entendimento do metabolismo e a regulação das células precursoras das fibras musculares merece atenção. Assim, o objetivo desta revisão narrativa é apresentar aspectos relacionados aos fatores de regulação das células satélites durante o processo de regeneração do músculo esquelético. A regeneração do músculo esquelético é um processo orquestrado que envolve a ativação e diferenciação das CSs. As interações celulares ocorrem com os diversos fatores miogênicos, de crescimento e hormonais. Entre eles destacam-se o HGF (fator de crescimento hepatocitário), IGF (fator de crescimento semelhante a insulina), MRFs (fatores regulatórios miogênicos), IL-6 (interleucina-6), VEGF (fator de crescimento vascular endotelial), Myf5 (fator miogênico 5), MRf4 (fator miogênico 4), MyoD (fator miogênico 1), androgênios e outros hormônios como a insulina. Todos estes fatores são dinâmicos e podem levar a uma maior compreensão da participação dessas células nos processos de regeneração tecidual. A interação com essas células promove ações positivas e negativas, levando a ativação ou inibição de suas atividades. O processo inflamatório e os fatores de crescimento atuam positivamente na diferenciação e proliferação celular. Entretanto, anti-inflamatórios, glicocorticoides e hormônios tireoidianos (T3) em excesso podem alterar o ciclo dessas células essenciais para o remodelamento tecidual. O entendimento de suas relações com as alterações fenotípicas e a sinalização que induzem modificações musculares é importante para o planejamento de estratégias de reabilitação e futuras terapias celulares.(AU)

The advance of molecular biology, cell biology and genetics has greatly improved our understanding of skeletal muscle biology, demonstrating that the biological characteristics of satellite cells (SCs) are essential in muscle regeneration. The therapeutic potential of these cells has been discussed in the literature, so the understanding of metabolism and regulation of precursor cells of the muscle fibers requires attention. The aim of this narrative review is to show aspects related to the regulatory factors of satellite cells during the process of skeletal muscle regeneration. Regeneration of skeletal muscle is an orchestrated process involving the activation and differentiation of SCs. The cellular interactions occur with various myogenic factors, growth factors and hormones. Stand out from HGF (Hepatocyte growth factor), IGF (insulin-like growth factor), MRFs (myogenic regulatory factors), IL-6 (interleukin-6), VEGF (vascular endothelial growth factor), Myf5 (myogenic factor 5), MRF4 (myogenic factor 4), MyoD (myogenic factor 1), androgens and other hormones such as insulin. All these factors are dynamic and can lead to a greater understanding of the role of cells in tissue regeneration processes. The interaction with these cells promotes positive and negative actions, leading to activation or inhibition of its activities. The inflammation and growth factors act positively on cell differentiation and proliferation. However, antiinflammatory, glucocorticoid and excess thyroid hormone (T3) may change the cycle of these cells essential to tissue remodeling. Understanding their relationship with the phenotypic changes and the signs inducing muscle changes is important for planning rehabilitation strategies and future cell therapies.(AU)

The role of p38 on the differentiation of MSCs to myoblasts / 中国应用生理学杂志

<p><b>AIM</b>Inducing mesenchymal stem cells (MSCs) differentiate to myoblasts with 5-azacytidine(5-Aza-CR), investigating the expression of Myf5 and the role of the signal transduction case of p38 in all the course of differentiation.</p><p><b>METHODS</b>Separating and purifying bone marrow-derived MSCs, inducing MSCs differentiation to myoblasts with 10 micromol/L 5-Aza-CR, assaying the gene expression time of Myf5 with RT-PCR method, the antigen expression of myosin with immunohistochemistry method and observing the changes of the activity of phosphorylation p38 before and after inhibited by SB203580 with Western-blot method.</p><p><b>RESULTS</b>MSCs begin to express Myf5 delayed to the 9th day after inhibited by SB203580. Some of MSCs express myosin at the 7th day after induced; The phosphorylation p38 activity of MSCs enhanced after induced by 5-Aza-CR but obviously decreased after inhibited by SB203580.</p><p><b>CONCLUSION</b>MSCs can express myogenic regulator factors and orientation differentiate to myoblasts after induced by 5-Aza-CR, p38 really have a positive signal transduction affection in this course.</p>