Abstract
Purpose :
NMNAT1, a gene involved in nicotinamide adenine dinucleotide (NAD) synthesis, was found to be responsible for a subset of LCA cases with sever macular atrophy. The molecular genetic findings suggest that NMNAT1 is critical for normal retinal development and maintanace of retinal function. To elucidate the function of NMNAT1 in developing normal retina and the pathophysiology of LCA, we examined the expression pattern of Nmnat1 in developing mouse retina and employed a loss of function using a mouse as a model system.
Methods :
To study of expression patterns of Nmnat1 during mouse retinal development, embryonic and post-natal eyes were analyzed immuno-histochemically using a specific antibody for NMNAT1. As for the loss-of-function analysis, we constructed plasmid based sh-RNA for mouse Nmnat1. The plasmid was electroporated into embryonic mouse retinal explants. The explants were cultured and examined by immunohistochemistry.In vivo electroporation into the eye of P1 mouse was performed to examine effects of the expression of these plasmids in postnatal retina. Gene transferred retinas were examined their morphology and gene expression by immunostaining of the sections and qPCR, respectively.
Results :
Expression pattern of Nmnat1 was changing drasitically during retinogenesis; it was expressed weakly in progenitor cells and strongly in retinal ganglion cells in embryonic retina. Then in differentiating and mature retina, Nmnat1 was strongly expressed in all the cells in inner nuclear layer (INL) and very weakly in rod photoreceptors. However, strong expression of Nmnat1 in developing and mature cone was observed. Loss-of-function of Nmnat1 in embryonic and postnatal mouse retina resulted in severe cell death in INL and over-expression of wild type Nmnat1 using electropolation partially rescued the phenotype.
Conclusions :
Expression pattern and loss-of-function analysis of Nmnat1 suggested Nmnat1 is critial for development and survival of cells in INL of retina.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.