Author(s): Yu M, Guan K, Zhang C
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Abstract Proliferation and cellular aggregation are both crucial features for survival and self-renewal of primordial germ cells (PGCs). Adhesive proteins play pivotal roles in cell-cell adhesion and signal exchanges under the influence of cytokines, growth factors and bioactive metabolites such as retinoic acid (RA). In this study, proliferation-promoting effect of RA on chicken PGCs was investigated by revealing changes in adhesive proteins E-cadherin and α/β catenins. PGCs were isolated from the genital ridge of 4-day-old chicken embryos and cultured on embryonic fibroblast feeder. RA (10(-7)-10(-5) M) increased PGCs aggregation and mRNA expression of E-cadherin and α/β-catenins. Furthermore, E-cadherin and β-catenin protein expression levels were increased by RA treatment. However, RA-elicited effect was significantly attenuated by a PKC inhibitor H(7). In addition, the number and area of PGC colonies were increased by RA treatment at 10(-7)-10(-5) M. Again, this increase was reduced by combined treatment of H(7). The proliferating effect of RA on PGCs was further confirmed by increased mRNA expression of cyclins, CCND1 and CCNE1, and cyclin-dependent kinases 6 and 2, which are critical for G1-S progression in cell cycle. Moreover, flow cytometry analysis confirmed that RA-treated PGC populations displayed a significant increase in the proportion of S and G2 phase cells. Likewise, this stimulating action was hindered by combined H(7) treatment. These results indicate that RA, as a bioactive metabolite of vitamin A, may promote PGC proliferation and increase intercellular aggregation of PGCs via E-cadherin and α/β-catenins expression through the PKC signaling pathway.
This article was published in Amino Acids
and referenced in Biological Systems: Open Access