Proteins Associated with Phagocytosis Alteration in Retinal Pigment Epithelial Cells Derived from Age-Related Macular...

Area of Science:

• Ophthalmology
• Cell Biology
• Genetics

Background:

• Age-related macular degeneration (AMD) is a leading cause of vision loss.
• Retinal pigment epithelial (RPE) cell dysfunction, including impaired phagocytosis, is a hallmark of AMD.

Purpose of the Study:

• To investigate phagocytosis activity in induced pluripotent stem cell-derived RPE (hiPSC-RPE) cells from AMD patients.
• To analyze the molecular mechanisms underlying phagocytosis alterations in AMD using transcriptomic and proteomic approaches.

Main Methods:

• Flow cytometry was used to assess phagocytic activity using porcine photoreceptor outer segments (POS) and fluorescent beads.
• Oxidative stress was induced using Fe-NTA.
• RNA-Seq based transcriptomic profiling and Western blot analysis were performed to examine gene and protein expression, focusing on the mTOR/PI3K-AKT/MEK-ERK pathway.

Main Results:

• hiPSC-RPE cells from both atrophic (AMDa) and exudative (AMDe) AMD forms showed altered basal phagocytosis compared to controls.
• Oxidative stress similarly inhibited phagocytosis in control and AMD hiPSC-RPE cells.
• Differential gene expression was observed post-POS incubation, implicating fak, tuberin, and rictor proteins in phagocytosis dysfunction.

Conclusions:

• hiPSC-RPE cells from AMD patients exhibit a disease phenotype characterized by impaired phagocytosis.
• Alterations in key proteins like fak, tuberin, and rictor contribute to RPE cell dysfunction in AMD.
• These findings highlight phagocytosis as a critical RPE function affected in AMD pathogenesis.