Expression of Hsp27 in retinal ganglion cells of the rat during postnatal development.
The small heat shock protein Hsp27 has been shown to protect neurons from apoptosis. We have recently shown the expression of Hsp27 in a subset of injured adult retinal ganglion cells (RGCs), a response that is muted by the administration of brain-derived neurotrophic factor. This work has suggested a role for Hsp27 in the long-term survival of RGCs following injury. The purpose of this study was to investigate the expression of Hsp27 during postnatal retinal development, based on Hsp27's role as a neuronal survival factor and on its up-regulation in the adult injured retina. Expression of Hsp27 in the developing retina was examined at various times postnatally (between P0 and P24) by using immunohistochemical techniques. We report that Hsp27 expression peaks in the ganglion cell layer between P6 and P12 and is not detected at earlier (P0-P3) or later (P15-P24) times. Double labeling of the Hsp27-positive cells with Fluorogold applied to the superior colliculus confirmed that Hsp27-positive cells in the ganglion cell layer are RGCs. We have shown developmentally regulated expression of Hsp27 in RGCs of the postnatal rat. The retinal expression of Hsp27 correlates temporally with innervation of the tectum by late-born RGCs and with onset of spontaneous retinotectal activity. We propose that the expression of Hsp27 may play an important role in retinal development during a critical period of RGC functional connectivity with the superior colliculus.
Hawkes
Erin L
EL
Neuron Survival and Regeneration Laboratory, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada.
Krueger-Naug
Anne Marie R
AM
Nickerson
Philip E B
PE
Myers
Tanya L
TL
Currie
R William
RW
Clarke
David B
DB
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000254:growth & development*; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D013477:Superior Colliculi / Q000378:metabolism; D014795:Visual Pathways / Q000378:metabolism
D006360:Heat-Shock Proteins