The Effects Of REST And IGF-1 On The Proliferation And Differentiation Of Retina Progenitor Cells

ObjectivesIn the current study,we investigated the role of REST and IGF-1 on the regulation of RPC proliferation and differentiation,which may provide a profound instruction for future treatment of retinal degeneration diseases.Methods1.RPCs were transfected with REST small interfering RNA(si REST)or treated with retinoic acid(RA)or Insulin-like growth factor-1(IGF-1)under proliferation medium.The CCK8,q PCR analysis,western blot and immunocytochemistry were used to test the effects of si REST,RA or IGF-1on RPC proliferation abilities.2.RPCs were transfected with si REST or RA under differentiation medium.The q PCR analysis,western blot and immunocytochemistry were used to test the effects of si REST or RA on RPC differentiation abilities.The mi R-29 a inhibitor and proteasome inhibitor were used to detect the regulation mechanism between REST and RA;RPCs were pre-treated with IGF-1 under proliferation medium for 3 days before cultured under differentiatin medium for 7 days.The western blot and immunocytochemistry were used to test expression levels of RPC differentiation markers.Results1.Under proliferation medium,the expression levels of REST were relatively high in RPCs.Transfected RPCs with si REST or treated RPCs with RA could suppress RPC proliferation ability;treated RPCs with IGF-1 could enhance RPC proliferation ability.2.Under differentiation medium,si REST or RA could promote RPC differentiate toward β3-tubulin-,rhodopsin-and recoverin-positive retinal neurons.RA could regulate REST expression partly through mi R-29 a and proteasomal degradation;IGF-1 pretreated RPCs showed more powerful ability of differentiation into retinal neurons than control group.Conclusion1.REST,RA and IGF-1 played an important role in RPC proliferation.Under proliferation medium,knock down the expression levels of REST could suppress RPC proliferation ability;exogenous RA could regulate RPC proliferation through suppressing REST expression levels from both transcriptional and post-transcriptional levels;exogenous IGF-1 could promote RPC proliferation ability.2.REST,RA and IGF-1 played an important role in RPC differentiation.Under differentiation medium,si REST or RA could promote RPCs differentiate towards β3-tubulin-,rhodopsin-and recoverin-positive retinal neurons ability.RA regulated the RPC differentiation by suppressing expression levels of REST partly through promoting mi R-29 a and proteasomal degradation;exogenous IGF-1 pre-treated RPCs could differentiate into retinal neurons more efficiently than control groups.These results provided a profound insight in the treatment of retinal degeneration diseases combined with REST,RA and IGF-1.