Cellular differentiation

About: Cellular differentiation is a research topic. Over the lifetime, 90966 publications have been published within this topic receiving 6099252 citations. The topic is also known as: Cellular differentiation & GO:0030154.

Human Umbilical Cord Perivascular (HUCPV) Cells: A Source of Mesenchymal Progenitors

Abstract: We describe the isolation of a nonhematopoietic (CD45-, CD34-, SH2+, SH3+, Thy-1+, CD44+) human umbilical cord perivascular (HUCPV) cell population. Each HUCPV cell harvest (2-5 x 10(6), depending on the length of cord available) gave rise to a morphologically homogeneous fibroblastic cell population, which expressed alpha-actin, desmin, vimentin, and 3G5 (a pericyte marker) in culture. We determined the colony-forming unit-fibro-blast (CFU-F) frequency of primary HUCPV cells to be 1:333 and the doubling time, which was 60 hours at passage 0 (P0), decreased to 20 hours at P2. This resulted in a significant cell expansion, producing over 10(10) HUCPV cells within 30 days of culture. Furthermore, HUCPV cells cultured in nonosteogenic conditions contained a subpopulation that exhibited a functional osteogenic phenotype and elaborated bone nodules. The frequency of this CFU-osteogenic subpopulation at P1 was 2.6/10(5) CFU-F, which increased to 7.5/10(5) CFU-F at P2. Addition of osteogenic supplements to the culture medium resulted in these frequencies increasing to 1.2/10(4) and 1.3/10(4) CFU-F, respectively, for P1 and P2. CFU-O were not seen at P0 in either osteogenic or non-osteogenic culture conditions, but P0 HUCPV cells did contain a 20% subpopulation that presented neither class I nor class II cell-surface major histocompatibility complexes (MHC-/-). This population increased to 95% following passage and cryopreservation (P5). We conclude that, due to their rapid doubling time, high frequencies of CFU-F and CFU-O, and high MHC-/- phenotype, HUCPV cells represent a significant source of cells for allogeneic mesenchymal cell-based therapies.

The role of depolarization in the survival and differentiation of cerebellar granule cells in culture

Abstract: Cultures greatly enriched in granule cells from early postnatal cerebellum (P8) were grown in a medium containing fetal calf serum. Under the conditions used, nerve cells died, usually within a week, unless the K+ concentration in the medium was greater than or equal to 20 mM. The requirement for elevated [K+]e was manifested by about 3 d in vitro, and after this time continuous exposure to high [K+]e was essential for the survival of the granule cells. The initial morphological and biochemical maturation of the granule cells was similar in the presence and the absence of elevated [K+]e, suggesting that the dependence on depolarizing conditions develops in parallel with the expression of the differentiated characteristics of the cells. The positive effect of elevated [K+]e on granule cell survival was not influenced by preventing bioelectric activity in the cultures with TTX and xylocaine. On the other hand, depolarization-induced transmembrane Ca2+ flux was essential in securing the maintenance of the granule cells. Depolarized nerve cells were compromised when Ca2+ entry was blocked by elevated Mg2+, EGTA, or organic Ca2+ antagonists, while dihydropyridine Ca2+ agonists [BAY K 8644, (+)-(S)-202 79 1 and CGP 28392] were potent agents preventing nerve cell loss in the presence of 15 mM [K+]e, which was ineffective on its own. Calmodulin inhibitors (1 microM trifluoperazine or calmidazolium) blocked the beneficial effect of K+-induced depolarization on granule cells. The comparison of the timing of the differentiation and innervation of the postmitotic granule cells in vivo with the development of the K+ dependence in vitro would indicate that depolarization of the granule neurons in culture mimics the influence of the physiological stimulation in vivo through excitatory amino acid receptors, including N-methyl-D-aspartate receptors, involving Ca2+ entry and the activation of a Ca2+/calmodulin- dependent protein kinase.

Human cerebral organoids recapitulate gene expression programs of fetal neocortex development

Abstract: Cerebral organoids—3D cultures of human cerebral tissue derived from pluripotent stem cells—have emerged as models of human cortical development. However, the extent to which in vitro organoid systems recapitulate neural progenitor cell proliferation and neuronal differentiation programs observed in vivo remains unclear. Here we use single-cell RNA sequencing (scRNA-seq) to dissect and compare cell composition and progenitor-to-neuron lineage relationships in human cerebral organoids and fetal neocortex. Covariation network analysis using the fetal neocortex data reveals known and previously unidentified interactions among genes central to neural progenitor proliferation and neuronal differentiation. In the organoid, we detect diverse progenitors and differentiated cell types of neuronal and mesenchymal lineages and identify cells that derived from regions resembling the fetal neocortex. We find that these organoid cortical cells use gene expression programs remarkably similar to those of the fetal tissue to organize into cerebral cortex-like regions. Our comparison of in vivo and in vitro cortical single-cell transcriptomes illuminates the genetic features underlying human cortical development that can be studied in organoid cultures.