Abstract
Purpose: :
Ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) exhibit multiple biological effects in the developing vertebrate retina. In vitro, CNTF suppresses rhodopsin expression in the rodent retina, induces late retinal progenitor cells to express bipolar cell markers, and promotes Müller glia genesis. In vivo expression of LIF in the embryonic lens also inhibits photoreceptor differentiation and reduces differentiation markers for all neuronal classes in the rodent retina. In this study, we examine the effects of CNTF during postnatal mouse retinal development in vivo by treating neonatal mice with lentivirus expressing secretable rat or human CNTF.
Methods: :
Recombinant lentiviruses were constructed to express secreted rat or human CNTF under a constitutive promoter. Viral stocks were produced using the third generation lentivirus packaging system. Expression and secretion of CNTF were characterized both in vitro and in vivo using Western blots and immunocytochemistry. CD1 mice were injected subretinally with lentiviral stocks at postnatal day 1 (P1), harvested at P7 or P36, and processed for immunocytochemical analysis.
Results: :
Lentivirus effectively expressed secreted rat/human CNTF in vitro and in vivo. Lentivrius infection was limited to the retinal pigment epithelium (RPE); but CNTF protein was detected throughout the retina. Viral expression of CNTF/GFP was detected within 3 days in vivo. Overexpression of CNTF during postnatal retinal development resulted in: a) suppression of both rhodopsin and cone opsin, b) dispersion of Müller glia and activation of GFAP, c) reduction of markers for differentiated retinal neurons, d) presence of PCNA positive progenitor-like cells in the outer nuclear layer.
Keywords: retinal development • growth factors/growth factor receptors • differentiation