Clusterin protein diversity in the primate eye

Area of Science:

• Ophthalmology
• Molecular Biology
• Genetics

Background:

• Clusterin, a multi-functional protein, is found in various tissues, including the eye.
• Its roles in lipid transport, membrane integrity, apoptosis, and neurodegeneration are relevant to ocular health.
• Previous studies indicated limited clusterin expression in human eye tissues compared to mouse.

Purpose of the Study:

• To confirm and detail clusterin expression in diverse human eye tissues.
• To establish the expression profile of clusterin in monkey-derived eye tissues.
• To determine if broad clusterin expression in the eye is consistent across primates.

Main Methods:

• Utilized monkey eye tissues for the majority of the study, with human tissues for confirmation.
• Employed Northern and Western blot analyses on monkey eye tissues.
• Conducted in situ hybridization and immunochemistry on human eye sections.

Main Results:

• Clusterin mRNA is expressed across multiple primate ocular tissues: lens, cornea, limbus, sclera, orbital muscle, ciliary body, retina, and RPE/choroid.
• Western analysis identified two main clusterin forms in the eye: a high molecular weight group (>100 kDa) and approximately 80 kDa species.
• Cultured RPE cells showed differential secretion patterns for various clusterin forms.

Conclusions:

• Clusterin exhibits broad expression in both human and monkey ocular tissues, indicating a conserved primate characteristic.
• Western analysis revealed diverse clusterin isoforms in monkey eyes, with identical mRNA sizes suggesting post-translational modifications.
• New insights into clusterin expression were established for the ciliary body, cornea, and retinal pigment epithelium.