Telomere-independent cellular senescence in human fetal cardiomyocytes
Telomere-independent cellular senescence in human fetal cardiomyocytes
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DOI：
10.1111/j.1474-9728.2004.00137.x
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发表时间：
2005-02-01
期刊：
影响因子：
7.8
通讯作者：
Levine, F
中科院分区：
文献类型：
--
作者：
Ball, AJ;Levine, F
胎儿心肌细胞被认为是心力衰竭细胞治疗的潜在来源。本研究探讨了细胞衰老在培养的人胎儿心室心肌细胞（HFCs）。采用免疫细胞化学和RT-PCR方法分离鉴定HFCs。发现细胞在20-25个群体倍增后衰老，如通过生长停滞、形态学变化和衰老相关的β-半乳糖苷酶活性所确定的。使用端粒重复序列扩增协议分析，端粒酶活性是不可检测的原发性氢氟碳化合物。转导细胞以表达端粒酶的人逆转录酶亚基（hTERT）。这导致端粒酶活性大大增加，但没有显着的寿命延长。端粒长度的分析显示，在初级氢氟碳化合物的衰老表型并不伴随着端粒缩短。端粒酶阳性细胞中的端粒延长与原代细胞相比，并延长在衰老细胞中保留。肿瘤抑制蛋白p16（INK 4A）的水平增加，在所有的衰老细胞，无论是端粒酶阳性或阴性。衰老伴随着polycomb基因Bmi-1，Ets 1和Ets 2转录因子，以及Id 1，Id 2和Id 3螺旋-环-螺旋蛋白的转录水平下降，表明这些基因在维持心肌细胞增殖能力中的作用。除了提供新的见解人类胎儿心肌细胞在文化中的行为，这些发现有影响的发展，基于细胞的治疗心脏损伤使用原代胎儿心脏组织。
Fetal cardiomyocytes have been proposed as a potential source of cell-based therapy for heart failure. This study examined cellular senescence in cultured human fetal ventricular cardiomyocytes (HFCs). HFCs were isolated and identified by immunocytochemistry and RT-PCR. Cells were found to senesce after 20-25 population doublings, as determined by growth arrest, morphological changes and senescence-associated beta-galactosidase activity. Using the telomeric repeat amplification protocol assay, telomerase activity was undetectable in primary HFCs. Cells were transduced to express the human reverse transcriptase subunit (hTERT) of telomerase. This resulted in greatly increased telomerase activity, but no significant lifespan extension. Analysis of telomere length in primary HFCs revealed that the senescent phenotype was not accompanied by telomere shortening. Telomeres in hTERT-positive cells were elongated in comparison with primary cells, and elongation was retained in senescent cells. Levels of the tumor suppressor protein p16(INK4A) increased in all senescent cells whether telomerase-positive or -negative. Senescence was accompanied by a decline in transcript levels of the polycomb gene Bmi-1, Ets1 and Ets2 transcription factors, and Id1, Id2 and Id3 helix-loop-helix proteins, suggesting roles for these genes in maintenance of cardiomyocyte proliferative capacity. In addition to offering novel insights into the behavior of human fetal cardiomyocytes in culture, these findings have implications for the development of a cell-based therapy for cardiac injury using primary fetal heart tissue.