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Kun-Che Chang, Catalina Sun, Xin Xia, Suqian Wu, Jeffrey L Goldberg; Study of Regulatory Mechanism of Growth Differentiation Factors on Retinal Ganglion Cell Development. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2590. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
What regulates neuronal differentiation and integration into mature circuits in the retinal ganglion cell (RGC)? This question has begun to be studied in neural development but also strongly impacts the adult nervous system. Growth and differentiation factor-11 (GDF-11) has been reported in neurogenesis. Here we evaluated the influence of GDF-11 and -15 on RGC fate specification.
Embryonic day 14 (E14), postnatal day 0 (P0), postnatal day 2 (P2) retinas were dissected from wild type (WT), Chx10-Cre/GDF-11 cKO and GDF-15 KO mice (N ≥ 6), respectively. Expression levels of marker genes and proteins with and without GDF treatment were determined by QPCR, Western blot and immunofluorescence staining. This research was conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Data were analyzed by ANOVA with Tukey’s test with P value of <0.05 considered statistically significant.
As measured by QPCR, RGC marker gene Brn3a was significantly upregulated in P0 GDF-11 KO retinas (p=0.016). Less Brn3a staining was observed in P2 GDF-15 KO retinas. Five days of GDF-11 treatment of E14 retinas downregulated the expression of RGC transcriptional regulators Math5 and Neurog2 and RGC marker genes Brn3a and RBPMS (p<0.05). In addition, RGC fate suppressing factors Notch1 and Hes5 were induced by GDF-11 (p<0.05). Smad2 was activated by GDF-11 but not GDF-15. Pharmacologic blockade of Smad2 signaling rescues GDF-11-reduced RGC fate and marker genes expression (p<0.05). Interestingly, pretreatment with GDF-15 attenuated GDF-11-induced phospho-Smad2 activation.
In this study, we investigate the effect of GDF-11 and -15 in developmental retina and reveal the regulatory mechanism in vivo and ex vivo. GDF-11 plays a suppressive role in RGC fate specification by activating Smad2-mediated Notch signaling. GDF-15 neutralizes GDF-11-mediated Smad2 activation and suppression of RGC differentiation, thereby promoting RGC fate specification. Understanding the role of GDFs in retina may provide a therapeutic strategy for RGC differentiation when considering cell replacement therapies.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Mechanism of GDF-11 on RGC fate specification
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