Model-based evaluation of connexin hemichannel permeability.

Area of Science:

• Cell biology
• Biophysics
• Molecular biology

Background:

• Connexin (Cx) hemichannels are large-pore channels involved in intercellular communication and physiological processes.
• Hemichannel permeability can be altered by mutations and biochemical factors, impacting cellular function.
• Quantifying these permeability changes is crucial for understanding Cx channel function in health and disease.

Purpose of the Study:

• To develop and validate a novel methodology for quantifying and comparing Cx hemichannel permeability.
• To integrate fluorescence imaging, electrophysiology, and mathematical modeling for robust permeability assessment.
• To establish a reliable method for detecting even subtle differences in hemichannel function.

Main Methods:

• Combined fluorescence imaging with mathematical modeling (Fick's law/GHK equation) to assess tracer diffusion.
• Integrated fluorescence data with electrophysiological recordings into a unified statistical model (likelihood ratio test).
• Validated the methodology's sensitivity using simulations and applied it to compare wild-type Cx26 and Cx26*A49E hemichannel permeability.

Main Results:

• The integrated methodology reliably detects significant differences in hemichannel permeability with moderate sample sizes (n < 100).
• The approach minimizes the need for extensive electrophysiological recordings by leveraging high-throughput fluorescence measurements.
• Demonstrated a significant increase in DAPI permeability for Cx26*A49E hemichannels compared to wild-type Cx26.

Conclusions:

• The developed methodology provides a sensitive and efficient way to quantify Cx hemichannel permeability.
• This approach facilitates the study of Cx channel function and the impact of mutations.
• The methodology is adaptable for assessing the permeability of other large-pore channel types.