April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Roles for methylation of H4K20 and 53BP1 in hypoxia-induced retinal ganglion cell death
Author Affiliations & Notes
  • Mari Katsura
    Radioisotope Center, The University of Tokyo, Tokyo, Japan
  • Reiko Yamagishi
    Ophthalmology, The University of Tokyo, Tokyo, Japan
  • Makoto Aihara
    Yotsuya Shirato Eye Clinic, Tokyo, Japan
  • Footnotes
    Commercial Relationships Mari Katsura, None; Reiko Yamagishi, None; Makoto Aihara, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 2397. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Mari Katsura, Reiko Yamagishi, Makoto Aihara, ; Roles for methylation of H4K20 and 53BP1 in hypoxia-induced retinal ganglion cell death. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2397.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract
 
Purpose
 

Understanding mechanisms of retinal ganglion cell (RGC) death is required for the prevention of blindness. Recently the roles of DNA damage responses and epigenetic modification of chromatin in apoptosis of neuron have been focused. Here we have investigated the alteration of DNA damage responses leading apoptosis induced by hypoxia using rat retinal ganglion cells.

 
Methods
 

RGCs were extracted from five to eight days old Wister rats with two-step panning procedure. After three days of incubation, the cultured RGCs were grown under 5% oxygen of hypoxia and analyzed. RGC-5 cells were also used for western blotting and cell cycle analysis after two days of serum starvation. Immunofluorescences were employed for analysis of nuclear foci formation by DNA damage response proteins, 53BP1 and γH2AX. Western blotting using anti-histone H4K20me1 and H4K20me2 analyzed the methylation of histone H4K20.

 
Results
 

First, in primary cultured rat RGC, the number of nuclear foci of 53BP1 from 0.60 per cell under normoxia to 0.37 per cell under hypoxia (p < 0.01). Correspondingly, apoptotic cells increased from 49.8% under normoxia to 78.2% under hypoxia (p < 0.05). Second, KU55933; a specific inhibitor for ataxia telangiectasia mutated (ATM), the upstream of 53BP1, decreased the number of 53BP1 nuclear foci from 0.71 per cell to 0.42 per cell (p < 0.05). Apoptotic cells increased from 49.8% with DMSO to 64.0% with KU55933 (p < 0.05). Under hypoxia, the numbers of 53BP1 foci were also decreased and apoptotic cells increased and H4K20me1 was down-regulated both by hypoxia and KU55933. Latanoprost, one of the PGF2alpha agonist, increased the methylation of H4K20 and reversed the 53BP1 foci from 0.35 per cell to 0.51 per cell (p < 0.05). Hypoxia-induced RGC death was suppressed from 87.6% under hypoxia to 58.7% with addition of 100 nM of latanoprost (p < 0.05).

 
Conclusions
 

Methylation of H4K20 and 53BP1 play roles in RGC survival and the mechanism is involved in neuroprotection by latanoprost.

 
 
Left: Nuclear focus of 53BP1 localizes to DNA damage site in primary cultured RGC Right: Suppression of 53BP1 foci formarion was reversed by latanoprost
 
Left: Nuclear focus of 53BP1 localizes to DNA damage site in primary cultured RGC Right: Suppression of 53BP1 foci formarion was reversed by latanoprost
 
 
Left: Suppression of H4K20me1 under hypoxia was recovered by latanoprost Right: Hypoxia induced apoptosis was canceled by latanoprost
 
Left: Suppression of H4K20me1 under hypoxia was recovered by latanoprost Right: Hypoxia induced apoptosis was canceled by latanoprost
 
Keywords: 531 ganglion cells • 426 apoptosis/cell death • 615 neuroprotection  
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×