Human-derived neural progenitors functionally replace astrocytes in adult mice

Area of Science:

• Neuroscience
• Stem Cell Biology
• Neurology

Background:

• Astrocytes are crucial for neural network homeostasis and neurological disease.
• Humans have a higher astrocyte-to-neuron ratio than other primates, but studying human astrocytes in vivo is challenging.
• Existing models do not fully capture the complexity of human astrocyte function in adult animals.

Purpose of the Study:

• To develop a chimeric animal model for studying human astrocytes in adult animals.
• To investigate the integration and function of human pluripotent stem cell-derived astrocytes in the mouse spinal cord.
• To explore the utility of this model for understanding human astrocyte roles in neurological disease, specifically Amyotrophic Lateral Sclerosis (ALS).

Main Methods:

• Transplantation of human pluripotent stem cell-derived (PSC-derived) neural progenitors into the cervical spinal cords of adult SCID mice.
• Longitudinal observation over 9 months to assess astrocyte migration, differentiation, and integration.
• Evaluation of structural integration through astrocyte network formation, ensheathment of neurons, and vascular wrapping.
• Assessment of functional integration by observing locomotion behaviors and motor deficits in mice transplanted with healthy versus ALS patient-derived PSCs.

Main Results:

• Human PSC-derived astrocytes successfully migrated long distances and replaced endogenous mouse astrocytes within 9 months.
• These human astrocytes formed networks, ensheathed neurons, and extended end feet around blood vessels, indicating structural integration without affecting locomotion.
• Mice transplanted with ALS patient-derived PSCs showed similar astrocyte integration but exhibited motor deficits, suggesting functional differences.
• The model demonstrated successful integration of human astrocytes and highlighted functional deficits in the context of ALS.

Conclusions:

• A novel chimeric animal model using human PSC-derived astrocytes in adult mice has been established.
• This model allows for the study of human astrocyte structural and functional integration within an intact adult mammalian nervous system.
• The model shows promise for investigating the pathogenesis of neurological diseases and evaluating potential repair strategies involving human astrocytes.