Preterm birth disrupts cerebellar development by affecting granule cell proliferation program and Bergmann glia

Area of Science:

• Neuroscience
• Developmental Biology
• Perinatal Medicine

Background:

• Preterm birth is a major cause of long-term motor and cognitive deficits.
• Cerebellar development disruption is implicated, but mechanisms remain unclear.
• It's unknown if preterm birth directly or indirectly affects cerebellar development.

Purpose of the Study:

• To investigate the mechanisms of cerebellar abnormalities in preterm infants.
• To determine if preterm birth directly impacts cerebellar development.
• To analyze gene expression changes in the cerebellum of preterm pigs.

Main Methods:

• Analyzed cerebellum of preterm pigs (91% term) raised to term-equivalent age.
• Used immunohistochemistry to assess cell populations and glial fibers.
• Performed qRT-PCR on the external granule cell layer to analyze gene expression.
• Conducted in vitro rescue experiments for Jag1.

Main Results:

• Preterm birth did not affect Purkinje cell or interneuron numbers/size.
• Reduced numbers of granule cell precursors and Bergmann glial fibers were observed.
• Granule cell proliferation was reduced, but differentiation was unaffected.
• Key genes (Ccnd1, Ccnb1, Atoh1, Jag1) showed reduced expression in preterm pigs.
• Jag1 was identified as a central gene affected by preterm birth.

Conclusions:

• Preterm birth and ex-utero exposure disrupt cerebellum development.
• This disruption occurs via modulation of key cerebellar developmental genes.
• Granule cell precursors and Bergmann glia development are predominantly affected.