Mitochondrial Maturation in Human Pluripotent Stem Cell Derived Cardiomyocytes

Human pluripotent stem cells derived cardiomyocytes (PSC-CMs) have been widely used for disease modeling, drug safety screening, and preclinical cell therapy to regenerate myocardium. Most studies have utilized PSC-CM grown in vitro for a relatively short period after differentiation. These PSC-CMs demonstrated structural, electrophysiological, and mechanical features of primitive cardiomyocytes. A few studies have extended in vitro PSC-CM culture time and reported improved maturation of structural and electromechanical properties. The degree of mitochondrial maturation, however, remains unclear. This study characterized the development of mitochondria during prolonged in vitro culture. PSC-CM demonstrated an improved mitochondrial maturation with prolonged culture, in terms of increased mitochondrial relative abundance, enhanced membrane potential, and increased activity of several mitochondrial respiratory complexes. These are in parallel with the maturation of other cellular components. However, the maturation of mitochondria in PSC-CMs grown for extended in vitro culture exhibits suboptimal maturation when compared with the maturation of mitochondria observed in the human fetal heart during similar time interval

Adipose Tissue-Derived Stem Cells from Humans and Mice Differ in Proliferative Capacity and Genome Stability in Long-Term Cultures

Adipose tissue-derived stem cells (ASCs) are among the more attractive adult stem cell options for potential therapeutic applications. Here, we studied and compared the basic biological characteristics of ASCs isolated from humans (hASCs) and mice (mASCs) and maintained in identical culture conditions, which must be examined prior to considering further potential clinical applications. hASCs and mASCs were compared for immunophenotype, differentiation potential, cell growth characteristics, senescence, nuclear morphology, and DNA content. Although both strains of ASCs displayed a similar immunophenotype, the percentage of CD73(+) cells was markedly lower and CD31(+) was higher in mASC than in hASC cultures. The mean population doubling time was 98.08 +/- 6.15 h for hASCs and 52.58 +/- 3.74 h for mASCs. The frequency of nuclear aberrations was noticeably lower in hASCs than in mASCs regardless of the passage number. Moreover, as the cells went through several in vitro passages, mASCs showed changes in DNA content and cell cycle kinetics (frequency of hypodiploid, G0/G1, G2/M, and hyperdiploid cells), whereas all of these parameters remained constant in hASCs. Collectively, these results suggest that mASCs display higher proliferative capacity and are more unstable than hASCs in long-term cultures. These results underscore the need to consider specificities among model systems that may influence outcomes when designing potential human applications.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[01/0009-0]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[05/54695-3]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[05/57591-4]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[04/06784-4]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[06/57937-0]Ministerio da Ciencia e Tecnologia/Conselho Nacional de Desenvolvimento Cientifico e Tecnologico/Ministerio da Saude/Departamento Ciencia e Tecnologia (MCT/CNPq/MS/DE-CIT)[552324/20005-1]Ministerio da Ciencia e Tecnologia/Conselho Nacional de Desenvolvimento Cientifico e Tecnologico/Ministerio da Saude/Departamento Ciencia e Tecnologia (MCT/CNPq/MS/DE-CIT)[10120104096700