Hyperglycemia-induced miR182-5p drives glycolytic and angiogenic response in Proliferative Diabetic Retinopathy and RPE cells via depleting FoxO1

PURPOSE

Diabetic Retinopathy (DR) is associated with metabolic dysfunction in cells such as retinal pigmented epithelium (RPE). Small molecular weight microRNAs can simultaneously regulate multiple gene products thus having pivotal roles in disease pathogenesis. Since miR182-5p is involved in regulating glycolysis and angiogenesis, two pathologic processes of DR, we investigated its status in DR eyes and in high glucose model in vitro.

METHOD

ology: Total RNA was extracted from vitreous humor of PDR (n = 48) and macular hole (n = 22) subjects followed by quantification of miR182-5p and its target genes. ARPE-19 cells, cultured in DMEM under differential glucose conditions (5 mM and 25 mM) were used for metabolic and biochemical assays. Cells were transfected with miRNA182 mimic or antagomir to evaluate the gain and loss of function effects.

RESULTS

PDR patient eyes had high levels of miR182-5p levels (p < 0.05). RPE cells under high glucose stress elevated miR182-5p expression with altered glycolytic pathway drivers such as HK2, PFKP and PKM2 over extended durations. Additionally, RPE cells under high glucose conditions exhibited reduced FoxO1 and enhanced Akt activation. RPE cells transfected with miR182-5p mimic phenocopied the enhanced basal and compensatory glycolytic rates observed under high glucose conditions with increased VEGF secretion. Conversely, inhibiting miR182-5p reduced Akt activation, glycolytic pathway proteins, and VEGF while stabilizing FoxO1.

CONCLUSION

Glycolysis-associated proteins downstream of the FoxO1-Akt axis were regulated by miR182-5p. Further, miR182-5p increased expression of VEGFR2 and VEGF levels, likely via inhibition of ZNF24. Thus, the FoxO1-Akt-glycolysis/VEGF pathway driving metabolic dysfunction with concurrent angiogenic signaling in PDR may be potentially targeted for treatment via miR182-5p modulation.

Distinct gene expression profiles underlie morphological and etiological differences in pediatric cataracts

Purpose

Pediatric cataract is a major cause of preventable childhood blindness worldwide. Although genetic mutations or infections have been described in patients, the mechanistic basis of human cataract development remains poorly understood. Therefore, gene expression of structural, developmental, profibrotic, and transcription factors in phenotypically and etiologically distinct forms of pediatric cataracts were evaluated.

Methods

This cross-sectional study included 89 pediatric cataract subjects subtyped into 1) prenatal infectious (cytomegalovirus, rubella, and combined cytomegalovirus with rubella infection), 2) prenatal non-infectious, 3) posterior capsular anomalies, 4) postnatal, 5) traumatic, and 6) secondary, and compared to clear, non-cataractous material of eyes with the subluxated lenses. Expression of lens structure-related genes (Aqp-0, HspA4/Hsp70, CrygC), transcription factors (Tdrd7, FoxE3, Maf, Pitx 3) and profibrotic genes (Tgfβ, Bmp7, αSmA, vimentin) in surgically extracted cataract lens material were studied and correlated clinically.

Results

In cataract material, the lens-related gene expression profiles were uniquely associated with phenotype/etiology of different cataracts. Postnatal cataracts showed a significantly altered FoxE3 expression. Low levels of Tdrd7 expression correlated with posterior subcapsular opacity, whereas CrygC correlated significantly with anterior capsular ruptures. The expression of Aqp0 and Maf was elevated in infectious cataracts, particularly in CMV infections, compared to other cataract subtypes. Tgfβ showed significantly low expression in various cataract subtypes, whereas vimentin had elevated gene expression in infectious and prenatal cataracts.

Conclusion

A significant association between lens gene expression patterns in phenotypically and etiologically distinct subtypes of pediatric cataracts suggests regulatory mechanisms in cataractogenesis. The data reveal that cataract formation and presentation is a consequence of altered expression of a complex network of genes.