Progressive Changes in a Distributed Neural Circuit Underlie Breathing Abnormalities in Mice Lacking MeCP2

Area of Science:

• Neuroscience
• Genetics
• Respiratory Physiology

Background:

• Rett syndrome (RTT) is a neurodevelopmental disorder linked to MECP2 mutations.
• Breathing abnormalities are a hallmark of RTT, observed in both patients and mouse models.
• Previous studies implicated hindbrain MeCP2 function in breathing control.

Purpose of the Study:

• To investigate the specific roles of MeCP2 in distinct brainstem respiratory circuits.
• To determine how MeCP2 loss in specific neuronal populations affects respiratory control.
• To elucidate the necessity of MeCP2 in different components of the respiratory network for survival and function.

Main Methods:

• Utilized the Cre/LoxP system for targeted deletion of MeCP2 in specific brainstem regions (HoxA4 domain).
• Employed whole-body plethysmography to assess respiratory phenotypes.
• Conducted electrophysiological recordings from in vitro brainstem slices to analyze neural activity.

Main Results:

• MeCP2 expression in the medullary respiratory network is sufficient for normal respiratory rhythm and apnea prevention.
• MeCP2 in HoxA4-derived tissues is critical for survival.
• MeCP2 in regions rostral to the HoxA4 domain is insufficient to prevent hyperventilation or abnormal hypoxic response.

Conclusions:

• MeCP2 plays differential roles in specific respiratory circuit components for various breathing functions.
• MeCP2 expression within the HoxA4 domain is essential for survival.
• Targeting MeCP2 function in distinct brainstem regions may offer therapeutic strategies for RTT-associated breathing disorders.