Abstract
Purpose :
The pathophysiology of primary open-angle glaucoma (POAG) is not exactly known. In this case-control study, we used next-generation sequencing (NGS) to identify microRNAs present in aqueous humor (AH) and blood from POAG and cataract (control) patients. Differentially expressed microRNAs could serve as biomarkers and provide insight into the pathogenesis of POAG.
Methods :
AH was collected from 6 POAG and 6 cataract patients undergoing cataract surgery (controls) or cataract surgery combined with an iStent implant (POAG). Blood plasma was collected on the same day. MicroRNAs were isolated, prepared with TruSeq library kit and subsequently sequenced on the Illumina HiSeq 2000 next-generation sequencing platform. The obtained reads were processed using miRDeep2 and mapped to known microRNA sequences retrieved from miRBase. The two groups were statistically compared using the DESeq2 package of R.
Results :
We obtained on average 186,219 ± 91,089 reads in AH. NGS of two AH samples failed due to technical issues. In total 111 microRNAs were identified with 54 ± 16 microRNAs per sample. 13 microRNAs were identified in all 10 AH samples. For plasma, reads were more abundant (8,553,748 ± 4,049,848) and mapped to 992 microRNAs (641 ± 139). 313 were found in every plasma sample. Hsa-mir-184 and hsa-mir-100-5p were detected in more AH samples than in plasma samples (χ2-test, p<0.05). While no statistical significance was reached between POAG and control, the results for several microRNAs in AH were promising considering the small sample size (hsa-mir-203a-3p, p<0.1; hsa-mir-199a-3p/199b-3p, p<0.15 and hsa-mir-204-5p, p<0.15).
Conclusions :
Using NGS we were able to identify more than 50 different microRNAs per AH sample and over 600 microRNAs per plasma sample. The detected microRNAs in AH are in line with previous studies. Our findings indicate that plasma and AH microRNA composition is clearly different. With the current sample size, the study was underpowered to reach significance. Nonetheless, our results suggest a dysregulation of several microRNAs in POAG. We are currently increasing the sample size and sequencing depth.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.