Pathophysiological analyses of periventricular nodular heterotopia using gyrencephalic mammals

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• Periventricular nodular heterotopia (PNH) is a common finding in the cerebral cortex of individuals with thanatophoric dysplasia (TD).
• The underlying pathophysiology of PNH in TD remains largely unknown due to challenges in obtaining human brain samples and the absence of suitable animal models.

Purpose of the Study:

• To investigate the pathophysiological mechanisms of PNH in the cerebral cortex of TD.
• To utilize a recently developed ferret model of TD to study PNH.

Main Methods:

• Development of a ferret model for TD by electroporating fibroblast growth factor 8 (FGF8) into the cerebral cortex.
• Immunohistochemical analysis of PNH nodules in the cerebral cortex of TD ferrets.

Main Results:

• PNH nodules in TD ferrets were primarily composed of cortical neurons, including upper layer and GABAergic neurons.
• Disorganizations of radial glial fibers and the ventricular lining were observed in the TD ferret cortex.
• These findings suggest PNH in TD may stem from impaired radial migration of cortical neurons.

Conclusions:

• The study provides novel mechanistic insights into the pathogenesis of PNH in TD.
• The ferret TD model is a valuable tool for studying PNH pathophysiology.
• Defects in radial glial fibers and neuronal migration are implicated in PNH development in TD.