Cardiac Regeneration: Time to Revisit Nature.
Cardiac Regeneration: Time to Revisit Nature.
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DOI：
10.1161/circresaha.118.313246
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发表时间：
2018-06
影响因子：
20.1
通讯作者：
S. Vadakke-Madathil;H. Chaudhry
中科院分区：
文献类型：
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作者：
S. Vadakke-Madathil;H. Chaudhry
After isolation from adult porcine ventricular tissue, cardiomyocytes were cultured, transfected with adenovirus containing Ccna2 versus null adenovirus, and the actinin-mCherry. We noted that≈ 3% of cultured adult porcine cardiomyocytes treated with Ccna2 adenovirus could be observed undergoing complete cytokinesis, resulting in intact daughter cells with preserved sarcomeres, compared with negligible numbers in cardiomyocytes treated with null adenovirus (see their online supplemental movie12). The numbers observed in vitro are not necessarily reflective of the increase in numbers of cardiomyocytes noted in vivo after gene therapy with Ccna2 and may be attributed to the technical difficulties of coaxing adult porcine cardiomyocytes into culture and maintaining them for the period of time required for such studies. However, this is the only way to verifiably and visually prove that cytokinesis was induced, as this phenomenon is thus far exceedingly difficult to visualize in vivo.This is an area of technical difficulty that we find in studies that examine proliferation of adult cardiomyocytes: inadequacies in assessing definitive cytokinesis. Furthermore, it is equally imperative to follow the survival and fate of daughter cardiomyocytes. In vitro cytokinesis assessment by dynamically labeling sarcomeres and visualization of cytokinesis using time-lapse fluorescence microscopy is vital to substantiate the incidence of cytokinesis in adult mammalian cardiomyocytes. Relying entirely on cell cycle/proliferation markers (Aurora B kinase or Ki-67) and to an extent the M-phase marker phospho-histone (H3P) may misrepresent actual cytokinesis if not confirmed by visualization of cell division in real time. Our ongoing studies explore the mechanistic basis of cell division in adult cardiomyocytes, more recently in adult human cardiomyocytes (work in progress). More recently, Mohamed et al14 also demonstrated a role for Cdk1 in combination with 3 other cell cycle regulators in murine cardiomyocyte proliferation. It is interesting to note this group did not report postnatal silencing of Ccna2 described by others and ourselves in multiple animal models and humans, 9–13 especially because the Ccna2/Cdk1 complex is critical for mitotic entry. Nonetheless, results of all of these studies allude to a potentially powerful strategy to finally achieve the end-goal of human cardiac regeneration, with Ccna2 gene delivery already having resulted in successful preclinical results of robust cardiac regeneration in the porcine model ready for clinical testing.
