In Vitro | In vitro activity: StemRegenin 1 increases the number of CD34+ cells after 5 to 7 days with an EC50 of 120 nM. Culture of mPB CD34+ cells with cytokines plus SR1 (1 μM) for 7 days increases the number of CD34+, CD133+, and CD90+ hematopoietic stem and progenitor cell populations 2.6-, 2.3-, and 10-fold, respectively compared to control cells. Continued culture with SR1 (1 μM) for 3 weeks leads to an 11-fold increase in total nucleated cells (TNC), a 73-fold increase in CD34+ cells as compared to control cultures, and a 1118-fold increase in CD34+ cells relative to input cells. Culture of 1×103cord blood CD34+ cells for 5 weeks with SR1 (1 μM) results in the production of 1.69×106 colony forming cells. SR1-induces CD34+ cell expansion acts by binding and antagonizing AhR as evident by decreased CYP1B1 and AHRR mRNA levels. SR1 (1 μM) treatment accelerates the proliferation of CD34+ cells and decreased the expression levels of VentX in human CD34+ cells. Ectopic expression of VentX prevents SR1-induced expansion of CD34+ cells. Sequential coculture with bone morphogenetic protein 4 (20 ng/mL), PGE2 (2 μM), and SR1 (0.75 μM) lead to robust Macaca nemestrina iPSC hematopoietic progenitor cell formation. CD34(+)CD38(-)Thy1(+)CD45RA(-)CD49f(+) cells isolated on the basis of CD34 expression and cultured in SR1 (0.75 μM) expands 3-fold and maintained this long-term repopulating HSC phenotype.
Cell Assay: CD34+UCB cells were cultured for 3 weeks with 1μM SR1 or 0.01% DMSO (control). Total cell number was determined at day 7, 14, and 21 and the frequency of pDCs was evaluated at each time point by flow cytometry. During the 3-weeks culture period the total nucleated cells continuously expanded. Analysis of pDC differentiation in time revealed that the maximum frequency of pDCs was already reached at day 14. However, the absolute number of pDCs was highest on day 21. |
---|