CCR1 mediates Müller cell activation and photoreceptor cell death in macular and retinal degeneration

Area of Science:

• Ophthalmology
• Immunology
• Cell Biology

Background:

• Mononuclear cells, particularly macrophages, play a critical role in the pathogenesis of retinal diseases like age-related macular degeneration (AMD).
• Understanding the specific mechanisms of macrophage-driven retinal cell death is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the mechanisms of macrophage-driven retinal cell death in the context of AMD.
• To identify potential therapeutic targets within the identified signaling pathways.

Main Methods:

• Human monocytes from AMD patients were differentiated into macrophages (hMdɸs) and characterized using proteomics and gene expression.
• Bioinformatics analysis identified key signaling pathways.
• Retinal explants and a photic injury model were used to assess macrophage function and therapeutic interventions.
• Inhibition of C-C chemokine receptor type 1 (CCR1) was tested.

Main Results:

• M2a macrophages (hMdɸs) were associated with retinal cell death in explants and a photic injury model.
• M2a hMdɸs express C-C chemokine receptor type 1 (CCR1) ligands, and CCR1 was upregulated in Müller cells during retinal injury and aging.
• CCR1 expression correlated with retinal damage.
• Inhibiting CCR1 reduced photic-induced retinal damage, photoreceptor apoptosis, and inflammation.

Conclusions:

• Human M2a macrophages, Müller cells, and CCR1 signaling are interconnected in driving retinal and macular degeneration.
• CCR1 represents a promising therapeutic target for treating sight-threatening retinal conditions like AMD.