Tracking Fenestrae Dynamics in Live Murine Liver Sinusoidal Endothelial Cells

Area of Science:

• Cell Biology
• Hepatology
• Biophysics

Background:

• Liver sinusoidal endothelial cells (LSECs) possess fenestrae crucial for passive transport between blood and liver cells.
• Previous studies relied on static electron microscopy, limiting understanding of fenestrae's dynamic nature.
• The dynamic properties and life cycle of LSEC fenestrae remained largely unknown.

Purpose of the Study:

• To investigate the dynamic properties of fenestrae and sieve plates in living LSECs.
• To elucidate the formation, lifespan, and disappearance mechanisms of LSEC fenestrae.
• To characterize fenestrae-forming and defenestration centers in LSECs.

Main Methods:

• Utilized advanced four-dimensional atomic force microscopy (4D AFM: X, Y, Z, and time).
• Performed time-lapse imaging on intact LSECs in vitro.
• Collected high-resolution structural data on fenestrae and sieve plates.

Main Results:

• Monitored fenestrae and sieve plate dynamics, including size, number, and position.
• Observed the complete life cycle of fenestrae, from formation to disappearance.
• Documented the dynamic rearrangement of sieve plates and identified fenestrae-forming/defenestration centers.

Conclusions:

• 4D AFM provides unprecedented insights into the dynamic behavior of LSEC fenestrae.
• Revealed the structural basis for fenestrae dynamics, including their formation and turnover.
• Identified three distinct pathways contributing to fenestrae loss and defenestrated LSECs.