This study successfully developed an Angpt2-miR-145 mouse model harboring the rs76020419 (G>T) mutation, demonstrating that this mutation elevates ANGPT2 expression and enlarges Schlemm's canal, suggesting its potential role in glaucoma protection 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 within the ANGPT2 3’UTR region. The mutation has been associated with reduced intraocular pressure (IOP) and decreased risk of primary open-angle glaucoma in genome-wide association studies (GWAS). This locus also exhibits eQTL characteristics in the GTEx database, correlating with ANGPT2 upregulation. The research team constructed a mouse model carrying this SNP using CRISPR/Cas9 technology, evaluating ANGPT2 expression and Schlemm's canal morphological changes across ocular tissues and systemic organs.
Background Knowledge
Glaucoma represents a leading cause of global blindness, affecting approximately 60 million individuals. Maintaining aqueous humor production-drainage equilibrium is critical for IOP regulation, with fluid primarily drained through the trabecular meshwork (TM) and Schlemm's canal (SC). Previous studies have linked ANGPT1 and TEK gene loss-of-function mutations to congenital glaucoma, while ANGPT2 can partially compensate for ANGPT1 deficiency. miR-145 is a known ANGPT2 suppressor; the rs76020419 (G>T) SNP disrupts this inhibitory effect, increasing ANGPT2 expression and potentially expanding SC diameter to lower IOP. No existing mouse models carrying this SNP have been available for in vivo validation, making this study a pivotal contribution to understanding ANGPT2's protective role in SC homeostasis and glaucoma prevention.
Research Methods and Experiments
The research team introduced the rs76020419 (G>T) mutation into C57BL/6 mice using CRISPR/Cas9 gene editing to create the Angpt2-miR-145 mouse model. ANGPT2 protein levels were quantified in plasma and tissues (ocular, pulmonary, renal) via qPCR and ELISA. Schlemm's canal area was analyzed through immunofluorescence staining and confocal microscopy. Intraocular pressure was measured using Tonolab rebound tonometry. Fluorescent angiography assessed vascular leakage to confirm model stability.
Key Conclusions and Perspectives
Research Significance and Prospects
The study establishes a functional link between increased ANGPT2 expression and structural modifications in Schlemm's canal, supporting its potential as a genetic protective factor against glaucoma. Future studies should integrate this mutation with various IOP elevation models to further evaluate its protective effects against ocular hypertension and retinal neurodegeneration, providing foundational insights for ANGPT2/miR-145-targeted therapeutic strategies.
Conclusion
This study represents the first in vivo validation in mice of the human ANGPT2 rs76020419 (G>T) mutation's impact on intraocular pressure and Schlemm's canal morphology. CRISPR/Cas9 technology successfully generated mutant mice with confirmed ANGPT2 upregulation across multiple tissues. The observed SC expansion and reduced IOP provide crucial evidence for miR-145-regulated ANGPT2 expression in ocular physiology. This model establishes a framework for investigating ANGPT2's protective mechanisms in glaucoma and related neurodegenerative diseases, while identifying novel molecular targets for gene therapy.
