Three-dimensional structured illumination microscopy of liver sinusoidal endothelial cell fenestrations

Area of Science:

• Cell biology
• Hepatology
• Microscopy

Background:

• Liver fenestrations are crucial for blood-hepatocyte exchange but their small size limits study.
• Fenestrations play roles in aging and lipoprotein regulation.

Purpose of the Study:

• To elucidate the 3D structure and location of fenestrations using advanced microscopy.
• To investigate the relationship between fenestrations, sieve plates, and cellular components.

Main Methods:

• Structured illumination microscopy (SIM) was used to visualize fenestrations in isolated rat liver sinusoidal endothelial cells.
• SIM provided high spatial resolution for 3D structural analysis.
• Fluorescent immunostaining was employed for co-localization studies.

Main Results:

• Fenestrations have a 3D diameter of 123+/-24 nm and occur in thin cytoplasmic regions (165+/-54 nm).
• Sieve plates were not co-localized with F-actin or eNOS, but with attenuated cell membrane regions.
• Fenestrations were identified as short cylindrical pores, not labyrinthine structures.

Conclusions:

• 3D SIM enables detailed structural and functional insights into liver fenestrations and sieve plates.
• This technique overcomes previous limitations in studying fenestrations.
• New information on fenestration morphology and cellular associations was revealed.