The Journal of Neuroscience, January 1, 2003, 23(1):252-259
DARP-36aa Selectively Promotes Survival and Morphological
Development of Cultured Mesencephalic Neurons
Sean M.
Smith and
Victor D.
Ramirez
Neuroscience Program, Department of Molecular and Integrative
Physiology, University of Illinois at Urbana-Champaign, Urbana,
Illinois 61801
We examined the effects of DARP-36aa on the survival and
morphological development of embryonic rat mesencephalic neurons. Treatment of mesencephalic cultures with DARP-36aa, a synthetic peptide
corresponding to the N terminal of dopamine-releasing protein (DARP),
resulted in a 1.8-fold increase in neuron survival. Morphological
analysis revealed that DARP-36aa-treated neurons contained 48% more
branching points per neuron compared with controls. DARP-36aa
selectively affected mesencephalic cultures; diencephalic and C6 glioma
cells were not affected by DARP-36aa treatments. Mesencephalic cultures
were also incubated with polyclonal antibodies against DARP-36aa
(anti-DARP-36aa) to assess the effect of immunoneutralization of
endogenous DARP on these cells. Mesencephalic cultures treated with
anti-DARP-36aa contained 43% fewer neurons, and the number of
branching points per neuron was decreased by nearly twofold compared
with cultures grown with medium alone. Similar to cultures treated with
DARP-36aa, immunoneutralization of DARP had no effect on any parameters
examined in primary diencephalic and C6 glioma cultures. Mesencephalic
cultures maintained in the presence of DARP-36aa had a 3.2-fold
increase in the number of tyrosine hydroxylase (TH)-immunoreactive
neurons, whereas anti-DARP-36aa incubations decreased TH-immunoreactive
neurons by 40% compared with control cultures. Finally, coincubation
of the specific tyrosine kinase inhibitor genistein with DARP-36aa
resulted in a complete attenuation of DARP-36aa-mediated neuron
survival and development in mesencephalic cultures. The findings
indicate that DARP-36aa is a novel neurotrophic peptide that
selectively promotes the survival and development of mesencephalic neurons.
Key words:
DARP-36aa; neurotrophic factor; mesencephalon; tyrosine hydroxylase; catecholamine; diencephalon
Copyright © 2003 Society for Neuroscience 0270-6474/03/231252-08$05.00/0