To investigate the characteristics of mutation
myocilin proteins and
glaucoma pathological phenotype in transgenic mice with full-length human Pro370Leu mutant
myocilin gene (Tg-MYOCP370L). Tg-MYOCP370L mice were established using the CRISPR/Cas9 system. Long-term intraocular pressure (IOP) was measured,
myocilin protein expressions in anterior chamber angle, retina, optic nerve tissues and aqueous humor were detected by western blot. RBPMS,
myocilin, Iba-1 and GFAP expression were visualized by immunofluorescence. H&E staining was applied to assess the ocular angle and
retinal morphology. Aqueous humor dynamics were visualized by
Gadolinium magnetic resonance imaging (Gd-MRI). TUNEL assay was used to evaluate the specific cell apoptosis in trabecular meshwork and retina. Optomotor and electroretinography tests were employed to evaluate the visual function in Tg-MYOCP370L and wild-type (WT) mice. Homozygous
myocilin mutation at position 503 (C > T) was identified by PCR and sequencing in Tg-MYOCP370L mice.
Myocilin protein expression was overexpressed in eye tissues of Tg-MYOCP370L mice with reduced
myocilin secretion in aqueous humor. H&E staining showed normal histological morphology of anterior chamber angle whereas decreased thickness and nuclei in
ganglion cell layer were found (P < 0.05). Gd signals were significantly increased in the anterior chamber of Tg-MYOCP370L compared with WT eyes (P < 0.05). IOP was elevated in Tg-MYOCP370L mice starting at 5 months of age, with significant RGC loss (P < 0.05). Upregulation of
caspase-3 and
caspase-9 expressions and increased TUNEL-positive cells were found in eyes of Tg-MYOCP370L mice. Excessive activation of
retinal glial cells and impaired visual function were detected in Tg-MYOCP370L mice. Tg-MYOCP370L mice can induce the phenotype of
open-angle glaucoma, featured as IOP elevation, activated
retinal glial cells, loss of RGCs and impaired visual function. These pathologic changes may arise from the abnormal mutant
myocilin protein accumulation in the trabecular meshwork and injured aqueous humor drainage. Therefore, Tg-MYOCP370L mice model can serve as an effective animal model for
glaucoma research, especially for
glaucoma-associated
myocilin mutation studies.