The study successfully constructed an Angpt2-miR-145 mouse model carrying the rs76020419 (G>T) mutation, confirming that this mutation increases ANGPT2 expression and correlates with enlarged Schlemm's canal area, suggesting its role in glaucoma's protective mechanisms. This model provides a critical tool for future investigations into ANGPT2's functions in intraocular pressure regulation and retinal neurodegeneration.
Literature Overview
This article, 'A Glaucoma-Protective Human SNP in the Angpt2 Locus,' published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology, reviews functional validation studies of rs76020419 (G>T), a human SNP located in the miR-145 binding site of the ANGPT2 3'UTR region. This mutation has been associated with reduced intraocular pressure (IOP) and lower risk of primary open-angle glaucoma in genome-wide association studies (GWAS). The locus also functions as an expression quantitative trait locus (eQTL) in the GTEx database, correlating with elevated ANGPT2 expression. The research team employed CRISPR/Cas9 technology to generate a murine model carrying this SNP and evaluated ANGPT2 expression and Schlemm's canal morphological changes across ocular and systemic tissues.
Background Knowledge
Glaucoma represents a leading cause of irreversible blindness globally, affecting approximately 60 million individuals. Maintenance of aqueous humor homeostasis between production and drainage through the trabecular meshwork (TM) and Schlemm's canal (SC) is essential for IOP regulation. Previous studies identified loss-of-function mutations in ANGPT1 and TEK genes as causative for congenital glaucoma, while ANGPT2 demonstrates compensatory capacity in the absence of Angpt1. miR-145, a known ANGPT2 suppressor, binds to this locus, and the rs76020419 (G>T) polymorphism disrupts this regulatory mechanism, resulting in increased ANGPT2 expression that may potentially enhance SC caliber and reduce IOP. This study fills a critical gap by providing the first in vivo validation model for this protective SNP.
Research Methods and Experiments
The research team introduced the rs76020419 (G>T) mutation into C57BL/6 mice using CRISPR/Cas9 gene editing technology to create the Angpt2-miR-145 mouse model. ANGPT2 protein levels were quantified across plasma and tissues (ocular, pulmonary, renal) via quantitative PCR and ELISA. Schlemm's canal area was analyzed using immunofluorescence staining combined with confocal microscopy. Intraocular pressure measurements were performed using Tonolab rebound tonometry. Fluorescein angiography was conducted to assess vascular integrity and model stability.
Key Conclusions and Perspectives
Research Significance and Prospects
The findings establish a functional relationship between elevated ANGPT2 expression and structural modifications of Schlemm's canal, supporting its potential as a genetic protective factor against glaucoma pathogenesis. Future studies combining this protective mutation with various ocular hypertension models could elucidate its neuroprotective effects against retinal ganglion cell degeneration. This work lays the foundation for developing therapeutic strategies targeting ANGPT2 or miR-145 pathways in glaucoma management.
Conclusion
This study represents the first in vivo validation of human ANGPT2 gene rs76020419 (G>T) mutation effects on intraocular pressure regulation and Schlemm's canal morphology in mice. Using CRISPR/Cas9 editing, the research team successfully generated a murine model with confirmed ANGPT2 upregulation across multiple tissues. The observed Schlemm's canal area enlargement and reduced IOP provide direct in vivo evidence for miR-145-mediated ANGPT2 expression regulation. This model establishes critical infrastructure for investigating ANGPT2's protective mechanisms in glaucoma and related neurodegenerative conditions, while identifying novel molecular targets for precision gene therapies.
