The effects of neuregulin and retinoic acid on embryonic stem cell derived embryoid bodies
Independently, neuregulin (NRG) and retinoic acid (RA) have known effects on embryonic stem cell (ESC) derived embryoid body (EB); however, the joint effects of NRG and RA are not known. In order to investigate whether the effects of NRG and RA on each other are synergistic or antagonistic, three separate 10 day experiments were carried out. EBs were cultured from ESC and exposed to NRG (20 and 30 ng/ml) on days 0–2 and 3–5, and a high (500 nM) and low (1 nM) concentration of RA on days 3–5. Immunocytochemisty (ICC) was conducted to determine whether markers for cardiomyocyte or neuron proteins were expressed. Real time polymerase chain reaction (RT-PCR) was conducted to determine whether makers for cardiomyocyte or neuron mRNAs were present. A high concentration of RA increased the expression of neuron markers and inhibited markers for cardiomyocytes, while NRG had no effect on either neuron or cardiomyocyte formation. Based on two experiments, there was no evidence for an effect of the low concentration of RA on promoting neurogenesis or inhibiting cardiomyogenesis, suggesting that a high concentration of RA is required to stimulate these processes. Although there was a trend for increased expression of GAP43 and TUJ1, neuron markers, and GATA4, an early cardiomyocyte marker, as a result of early NRG exposure accompanied by later exposure to the high concentration of RA, further experiments are needed to establish this result. Thus our question whether there is synergy or antagonism between NRG and RA will require further assessment. Answering this question is a complex experiment. It requires knowing the timing, concentration, and identity of key factors as shown by the work reported here. As shown here, we can conclude that a high concentration of RA promotes neurogenesis and inhibits cardiomyogenesis. These results corroborate studies reported by other laboratories which employed research protocols similar to ones used here.
"The effects of neuregulin and retinoic acid on embryonic stem cell derived embryoid bodies"
ETD Collection for Tennessee State University.