The Journal of Neuroscience, April 15, 2000, 20(8):2917-2925
Regulation of Glial Cell Line-Derived Neurotrophic Factor
Responsiveness in Developing Rat Sympathetic Neurons by Retinoic Acid
and Bone Morphogenetic Protein-2
Siong Heng
Thang,
Miwako
Kobayashi, and
Ichiro
Matsuoka
Graduate School of Pharmaceutical Sciences, Hokkaido University,
Kita-Ku, Sapporo 060-0812, Japan
There are several lines of evidence suggesting that, in addition to
neurotrophins, member(s) of glial cell line-derived neurotrophic factor
(GDNF) family play important roles in the development of sympathetic neurons. However, the mechanism regulating the
responsiveness of the neurons to GDNF family members is not known.
Previously, we reported on the cooperative roles of bone morphogenetic
protein-2 (BMP2) and retinoic acid (RA) in the enhancement of
neurotrophin-3 (NT3) responsiveness in cultured sympathetic neurons
dissociated from perinatal rat superior cervical ganglia (SCG). In the
present study, we further examined the effects of BMP2 and RA on the
regulation of the responsiveness of SCG neurons to GDNF family members.
Consequently, we found that RA alone induced the responsiveness of SCG
neurons specifically to GDNF by upregulating the ligand-specifying
receptor for GDNF (GFR
-1) at both the mRNA and protein levels. The
expression levels of mRNAs for other ligand-specifying receptors for
GDNF family (GFR
-2 and GFR
-3) were unaffected by RA. Although the upregulation of signal-transducing receptor Ret by the RA treatment was
rather small, this treatment significantly increased the efficacy of
tyrosine phosphorylation of Ret by GDNF. Experiments using synthetic
retinoids suggested that RA acts through
-type of nuclear retinoic
acid receptor to exert the induction of GDNF responsiveness. On
the other hand, BMP2, which had no significant effect by itself on the
GDNF responsiveness, promoted the action of RA to upregulate GFR
-1
and enhance the GDNF responsiveness. These results indicate that RA and
BMP2 play important roles in the induction of GDNF responsiveness, as
well as NT3 responsiveness, of developing SCG neurons.
Key words:
neurotrophic factor; GDNF; GFR
-1; BMP2; retinoic acid; RAR
; SCG neurons
Copyright © 2000 Society for Neuroscience 0270-6474/00/2082917-09$05.00/0