title: Overexpression of neurotrophin-3 stimulates a second wave of dopaminergic amacrine cell genesis after birth in the mouse retina.
abstract: Dopaminergic amacrine (DA) cells play multiple and important roles in retinal function. Neurotrophins are known to modulate the number and morphology of DA cells, but the underlying regulatory mechanisms are unclear. Here, we investigate how neurotrophin-3 (NT-3) regulates DA cell density in the mouse retina. We demonstrate that overexpression of NT-3 upregulates DA cell number and leads to a consequent increase in the density of DA cell dendrites. To examine the mechanisms of DA cell density increase, we further investigate the effect of NT-3 overexpression on retinal apoptosis and mitosis during development. We find that NT-3 does not affect the well known wave of retinal cell apoptosis that normally occurs during the first 2 weeks after birth. Instead, overexpression of NT-3 promotes additional mitosis of DA cells at postnatal day 4, but does not affect cell mitosis before birth, the peak period of amacrine cell genesis in wild-type retinas. We next show that retinal explants cultured from birth to day 7 without extra NT-3 produced by lens exhibit similar number of DA cells as in wild type, further supporting the notion that postnatal overexpression of lens-derived NT-3 affects DA cell number. Moreover, the additional mitosis after birth in NT-3-overexpressing mice does not occur in calretinin-positive amacrine cells or PKC-positive rod ON bipolar cells. Thus, the NT-3-triggered wave of cell mitosis after birth is specific for the retinal DA cells.
authors: Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA.
authors: Miho
authors: M
authors: Yoshida
authors: Liang
authors: L
authors: Feng
authors: François
authors: F
authors: Grimbert
authors: Krsna V
authors: KV
authors: Rangarajan
authors: William
authors: W
authors: Buggele
authors: David R
authors: DR
authors: Copenhagen
authors: Jianhua
authors: J
authors: Cang
authors: Xiaorong
authors: X
authors: Liu
mesh_terms: D025042:Amacrine Cells / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism; D064032:Calbindin 2; D002453:Cell Cycle / Q000235:genetics; D016923:Cell Death; D004298:Dopamine / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D020287:In Situ Nick-End Labeling / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D055495:Neurogenesis / Q000235:genetics / Q000502:physiology*; D020933:Neurotrophin 3 / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D012160:Retina / Q000166:cytology*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: C576511:Calb2 protein, mouse; D064032:Calbindin 2; D020933:Neurotrophin 3; D064030:S100 Calcium Binding Protein G; D014446:Tyrosine 3-Monooxygenase; D011493:Protein Kinase C; D001973:Bromodeoxyuridine; D004298:Dopamine