Functional microglia derived from human pluripotent stem cells empower retinal organ

Area of Science:

• Neuroscience
• Stem Cell Biology
• Ophthalmology

Background:

• Microglia are crucial in neurodegenerative diseases affecting the central nervous system, including the retina.
• Previous research generated brain-induced microglia-like cells (iMGs) from human pluripotent stem cells (hPSCs), but retinal microglia lacked in vitro models.
• Understanding retinal microglia is vital for neurodegenerative disease research and therapeutic development.

Purpose of the Study:

• To establish a simplified and efficient method for differentiating hPSCs into high-purity iMGs.
• To investigate the behavior and characteristics of these iMGs when co-cultured with human retinal organoids (hROs).
• To report the first successful derivation of retina-resident microglia in vitro.

Main Methods:

• Mimicking in vivo microglial development to differentiate hPSCs into iMGs with >90% purity.
• Characterizing iMGs by assessing microglia-specific markers, cytokine release upon stimulation, and phagocytic activity.
• Co-culturing iMGs with 3D hROs to observe migration, differentiation, and interaction with retinal cells.

Main Results:

• Generated high-purity iMGs (>90%) from hPSCs using a simplified differentiation protocol.
• Confirmed iMGs express microglia markers, release cytokines, and exhibit phagocytosis.
• Observed iMGs migrating into hROs, differentiating into resident retinal microglia, and inducing neural cell apoptosis.
• Demonstrated iMGs forming web-like structures in hROs, mimicking in vivo retinal microglia orientation.

Conclusions:

• Developed a simplified and efficient method for generating microglia from hPSCs.
• Successfully derived retina-resident microglia in vitro for the first time.
• Established a valuable new source of human retinal microglia for research and therapeutic applications.