近日,，《細(xì)胞—代謝》（Cell Metabolism）發(fā)表了法國(guó)國(guó)家健康和醫(yī)學(xué)研究院（INSERM）的一項(xiàng)新研究，為我們解釋了肌細(xì)胞是如何在負(fù)重運(yùn)動(dòng)時(shí)后變粗大的,。
肌肉變大的奧秘在于肌細(xì)胞在運(yùn)動(dòng)（如舉重）過(guò)程中會(huì)產(chǎn)生一種化學(xué)物質(zhì)，這種化學(xué)物質(zhì)會(huì)給肌肉干細(xì)胞發(fā)出信號(hào),，使其分化從而承受負(fù)重,。名為血清反應(yīng)因子(Srf)的物質(zhì)激發(fā)了可以分化成肌細(xì)胞但處于休眠狀態(tài)下的肌肉干細(xì)胞，使其生長(zhǎng)并形成肌纖維,，肌纖維越多就意味著肌肉和力量越大,。
研究員索蒂羅波羅斯（Athanassia Sotiropoulos）認(rèn)為，來(lái)自肌纖維的信號(hào)可以控制干細(xì)胞的行為和參與肌肉的生長(zhǎng),，這是出乎意料且十分有趣的發(fā)現(xiàn),，這些研究結(jié)果將有助于人們找到，因年齡和疾病引發(fā)的肌肉萎縮問(wèn)題的方法,。
研究人員對(duì)實(shí)驗(yàn)小鼠進(jìn)行了基因改造,，使它們的肌肉中缺少血清反應(yīng)因子，之后研究人員發(fā)現(xiàn),，沒(méi)有這種因子,，就算小鼠進(jìn)行負(fù)載運(yùn)動(dòng)肌肉也沒(méi)有增長(zhǎng)。索蒂羅波羅斯說(shuō)道,，血清反應(yīng)因子通過(guò)基因網(wǎng)絡(luò)來(lái)釋放信號(hào),，這其中包括一種名為Cox2的基因。消炎藥（如布洛芬）會(huì)阻礙Cox2的活動(dòng)，因此這些藥物有可能會(huì)抑制肌肉的生長(zhǎng),。她表示,，以增長(zhǎng)肌肉為目標(biāo)的治療方法（比如長(zhǎng)期臥床后的恢復(fù)）也可以把重心轉(zhuǎn)向血清反應(yīng)因子復(fù)雜的化學(xué)網(wǎng)絡(luò)上來(lái),。(生物谷Bioon.com)
doi:10.1016/j.cmet.2011.12.001
PMC:
PMID:
Srf-Dependent Paracrine Signals Produced by Myofibers Control Satellite Cell-Mediated Skeletal Muscle Hypertrophy
Aline Guerci, Charlotte Lahoute, Sophie Hébrard, Laura Collard, Dany Graindorge, Maryline Favier, Nicolas Cagnard, Sabrina Batonnet-Pichon, Guillaume Précigout, Luis Garcia, David Tuil, Dominique Daegelen, Athanassia Sotiropoulos
Adult skeletal muscles adapt their fiber size to workload. We show that serum response factor (Srf) is required for satellite cell-mediated hypertrophic muscle growth. Deletion of Srf from myofibers and not satellite cells blunts overload-induced hypertrophy, and impairs satellite cell proliferation and recruitment to pre-existing fibers. We reveal a gene network in which Srf within myofibers modulates interleukin-6 and cyclooxygenase-2/interleukin-4 expressions and therefore exerts a paracrine control of satellite cell functions. In Srf-deleted muscles, in vivo overexpression of interleukin-6 is sufficient to restore satellite cell proliferation but not satellite cell fusion and overall growth. In contrast cyclooxygenase-2/interleukin-4 overexpression rescue satellite cell recruitment and muscle growth without affecting satellite cell proliferation, identifying altered fusion as the limiting cellular event. These findings unravel a role for Srf in the translation of mechanical cues applied to myofibers into paracrine signals, which in turn will modulate satellite cell functions and support muscle growth.
