Abstract
Purpose :
Given the increasing prevalence of diabetic retinopathy (DR), it is of utmost importance to identify newer biomarkers that can help with early diagnosis and prevent the progression to proliferative form of DR. In recent years, the hematopoietic stem cells (HSCs) have gained substantial attention to play a significant role in the pathophysiology of DR; however, there is a gap in the knowledge with regards to transcriptional changes in the HSCs of diabetes and DR. Therefore, we attempted to investigate the HSC’s transcriptome using rodents and clinical subjects.
Methods :
A leptin receptor-deficient (db/db) mice and age-matched control (db/m) mice were used as an animal model of type 2 diabetes (T2D), and a pure population of bone marrow-derived lin-Sca1-cKit+ (LSK; HSCs) were isolated and sequenced. Parallelly, we recruited individuals with 1) no diabetes 2) diabetes with no DR, and 3) varying severity of DR. Blood samples were collected from all the individuals to isolate HSCs, which were then a) analyzed for the angiogenic and inflammatory cell surface expression and b) sorted for the lin-CD34+ CD45mid cells and subsequently sequenced for the miRNA and mRNA.
Results :
A significantly higher number of Sca1-ckit+ HSCs (p=0.0362) were found in the bone marrows of db/db mice, suggesting stem cell mobilopathy in chronic T2D. Similarly, in the clinical study, we observed a decrease in the number of circulatory CD34+ HSCs in the proliferative DR state. The cell surface expression analysis showed increased TLR8+ and CD11+ cells in DR individuals. The miRNA sequencing reflected 35 and 9 miRNAs with significant differences (p<0.05) in mice and clinical samples, respectively. Further analysis of the downstream mRNA targets revealed an involvement of pro-inflammatory, pro-angiogenic, and macrophage activation pathways. Additionally, there were 105 common mRNAs between rodent and clinical studies, primarily targeting IL-15 signaling and spliceosome formation.
Conclusions :
The present study offers an excellent opportunity to identify an easily assessable peripheral blood-derived HSCs-based miRNA biomarker that can ease the identification of DR at early stages. Furthermore, the sequencing data have revealed unique miRNAs and mRNAs, which can be further studied for their applicability.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.