Abstract
Purpose :
Purpose: Human retinal progenitor cells (hRPCs) have been shown to protect existing photoreceptors and preserve vision in preclinical models of retinal degeneration. We tested the hypothesis that hRPCs would suppress the gene expression changes seen in AMD by utilizing a cell co-culture system consisting of hRPCs and a transmitochondrial cybrid model of AMD.
Methods :
Transmitochondrial cybrids containing identical healthy nuclei but mitochondria from different individual AMD patients were created by fusing DNA-deficient ARPE-19 (Rho0) cells with platelets isolated from AMD patients that were clinically well characterized. The transmitochondrial cybrid lines (N=3) were grown with and without the presence of hRPCs using a transwell system. RNA was extracted at 48 hours and reverse transcribed into cDNA. qRT-PCR was performed to assess the expression of apoptosis, autophagy, and ER stress genes. Relative expression was determined using the ΔΔCt method followed by Student’s t-test.
Results :
Expression of genes associated with cell damage and death were decreased in the hRPC-treated cells compared to untreated controls (reported as percent expression +/- SEM). Apoptosis genes: BAX (67.4% +/- 1.5%, p=0.0020), CASP7 (68.9% +/- 2.3%, p=0.0054), CASP9 (89.8% +/- 3.0%, p=0.0746). Autophagy genes: ATG5 (82.9% +/- 1.4%, p=0.0065), ATG12 (65.9% +/- 16.6%, p=0.0704), p=.0271), LAMP2 (63.2% +/- 4.5%, p=0.0149), LC3B (86.3% +/- 2.7%, p=0.0378), PARK2 (70.9% +/- 2.8%, p=0.0091). ER stress genes: DDIT3 (45.2% +/- 15.9%[J1] , p=0.0271), XBP1 (70.2% +/- 3.0%, p=0.0101).
Conclusions :
Co-culture with hRPCs decreased expression of genes associated with cell damage and death in AMD transmitochondrial cybrids. These results suggest that hRPCs release factors that are protective against the cellular changes involved in AMD pathogenesis.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.