ABCA1 Deletion Does Not Affect Aqueous Humor Outflow Function in Mice.

Background: ATP binding cassette transporter A1 (ABCA1) is a candidate gene within a POAG susceptibility locus by GWAS analysis, and it is involved in IOP modulation via the Cav1/eNOS/NO signaling pathway. We aim to examine the phenotype of ABCA1 deletion in the ABCA1 gene knockout (Abca1^-/-) mice.

Methods: The anterior segments of Abca1^-/- eyes were imaged by slit-lamp microscopy and anterior segment OCT. IOPs were measured by rebound tonometry. By perfusing enucleated eyes at various pressures, the aqueous humor outflow facility was determined. The mRNA expressions of ABCA1, Cav1, and eNOS were measured by RT-qPCR. The protein expressions were analyzed by western blot and immunofluorescence staining.

Results: There was no significant difference in the anterior segment morphology of Abca1^-/- mice. IOP and aqueous humor outflow facility did not change in Abca1^-/- mice compared with wild-type mice. mRNA and protein expressions of ABCA1 were significantly lower in the outflow tissue of Abca1^-/- eyes. The expressions of Cav1 and eNOS were both significantly upregulated in the outflow tissue of Abca1^-/- eyes.

Conclusion: ABCA1 deletion does not affect IOP and aqueous humor outflow function but the Cav1/eNOS/NO pathway is changed in Abca1^-/- mice. The function of ABCA1 in aqueous humor outflow still requires further research.