Neurogenin1 effectively reprograms cultured chick retinal pigment epithelial cells to differentiate toward photoreceptors.
Photoreceptors are highly specialized sensory neurons in the retina, and their degeneration results in blindness. Replacement with developing photoreceptor cells promises to be an effective therapy, but it requires a supply of new photoreceptors, because the neural retina in human eyes lacks regeneration capability. We report efficient generation of differentiating, photoreceptor-like neurons from chick retinal pigment epithelial (RPE) cells propagated in culture through reprogramming with neurogenin1 (ngn1). In reprogrammed culture, a large number of the cells (85.0% +/- 5.9%) began to differentiate toward photoreceptors. Reprogrammed cells expressed transcription factors that set in motion photoreceptor differentiation, including Crx, Nr2E3, NeuroD, and RXRgamma, and phototransduction pathway components, including transducin, cGMP-gated channel, and red opsin of cone photoreceptors (equivalent to rhodopsin of rod photoreceptors). They developed inner segments rich in mitochondria. Furthermore, they responded to light by decreasing their cellular free calcium (Ca(2+)) levels and responded to 9-cis-retinal by increasing their Ca(2+) levels after photobleaching, hallmarks of photoreceptor physiology. The high efficiency and the advanced photoreceptor differentiation indicate ngn1 as a gene of choice to reprogram RPE progeny cells to differentiate into photoreceptor neurons in future cell replacement studies.
Yan
Run-Tao
RT
Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0009, USA.
Liang
Lina
L
Ma
Wenxin
W
Li
Xiumei
X
Xie
Wenlian
W
Wang
Shu-Zhen
SZ
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D019521:Body Patterning / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology / Q000528:radiation effects; D002454:Cell Differentiation / Q000502:physiology; D002642:Chick Embryo; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D055537:Light Signal Transduction / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D055495:Neurogenesis / Q000502:physiology; D010641:Phenotype; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D017299:Rod Opsins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015293:Transducin / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; D017299:Rod Opsins; D014157:Transcription Factors; D015293:Transducin; C095855:long-wavelength opsin; C486336:Neurog1 protein, mouse