OTX2 stimulates adult retinal ganglion cell regeneration

Retinal ganglion cell(RGC) axons provide the only link between the light sensitive and photon transducing neural retina and visual centers of the brain.RGC axon degeneration occurs in a number of blinding diseases and the ability to stimulate axon regeneration from surviving ganglion cells could provide the anatomic substrate for restoration of vision.OTX2 is a homeoprotein transcription factor expressed in the retina and previous studies showed that,in response to stress,exogenous OTX2 increases the in vitro and in vivo survival of RGCs.Here we examined and quantified the effects of OTX2 on adult RGC axon regeneration in vitro and in vivo.The results show that exogenous OTX2 stimulates the regrowth of axons from RGCs in cultures of dissociated adult retinal cells and from explants of adult retinal tissue and that RGCs respond directly to OTX2 as regrowth is observed in cultures of purified adult rat RGCs.Importantly,after nerve crush in vivo,we observed a positive effect of OTX2 on the number of regenerating axons up to the optic chiasm within 14 days post crush and a very modest level of acuity absent in control mice.The effect of OTX2 on RGC survival and regeneration is of potential interest for degenerative diseases affecting this cell type.All animal procedures were approved by the local "Comié d'éιthique en expérimentation animale n°59" and authorization n° 00702.01 delivered March 28,2014 by the French "Ministére de l'enseignement supérieur et de la recherche".

Comparison of human nasal epithelial cells grown as explant outgrowth cultures or dissociated tissue cultures in vitro

The purpose of this study was to compare cell growth characteristics,ciliated cell differentiation,and function of human nasal epithelial cells established as explant outgrowth cultures or dissociated tissue cultures.Human nasal mucosa of the uncinate process was obtained by endoscopy and epithelial cell cultures were established by explant outgrowth or dissociated tissue culture methods.Epithelial cell growth characteristics were observed by inverted phase contrast microscopy.Ciliated cell differentiation was detected byβ-tubulin IV and ZO-1 immunocytochemistry.Basal and ATP-stimulated ciliary beat frequency(CBF)was measured using a high-speed digital microscopic imaging system.Both the explant and dissociated tissue cultures established as monolayers with tight junctions and differentiated cell composition,with both types of cultures comprising ciliated and non-ciliated epithelial cells.Fibroblasts were also frequently found in explant cultures but rarely seen in dissociated tissue cultures.In both culture systems,the highest ciliated cell density appeared at 7th–10th culture day and declined with time,with the lifespan of ciliated cells ranging from 14 to 21 days.Overall,10%of the cells in explant cultures and 20%of the cells in the dissociated tissue cultures were ciliated.These two cultures demonstrated similar ciliary beat frequency values at baseline(7.78±1.99 Hz and 7.91±2.52 Hz,respectively)and reacted equivalently following stimulation with 100μM ATP.The results of this study indicate that both the explant outgrowth and dissociated tissue culture techniques are suitable for growing well-differentiated nasal ciliated and non-ciliated cells,which have growth characteristics and ciliary activity similar to those of nasal epithelial cells in vivo.