HtrA chaperone activity contributes to host cell binding in Campylobacter jejuni

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• Campylobacter jejuni causes acute gastroenteritis through attachment and invasion of intestinal epithelial cells.
• The periplasmic protein HtrA in C. jejuni is essential for efficient binding to host cells.
• HtrA possesses both protease and chaperone activities, contributing to the virulence of various bacterial pathogens.

Purpose of the Study:

• To elucidate the distinct roles of HtrA's protease and chaperone activities in C. jejuni's interaction with host cells.
• To compare the host cell interaction capabilities of a wild-type C. jejuni strain, a ΔhtrA mutant, and an htrA mutant with intact chaperone activity but lacking protease function.

Main Methods:

• Comparative analysis of bacterial-host cell binding using wild-type C. jejuni, ΔhtrA mutant, and a protease-deficient htrA mutant.
• Assessment of bacterial interaction with intestinal epithelial cells and macrophages.

Main Results:

• HtrA's chaperone activity significantly facilitates the binding of C. jejuni to both epithelial cells and macrophages.
• This chaperone activity is potentially involved in the proper folding of outer membrane adhesins, crucial for bacterial attachment.
• HtrA's protease activity demonstrated a minor contribution to the overall interaction with host cells.

Conclusions:

• HtrA's protease and chaperone activities differentially impact C. jejuni's interaction with mammalian host cells.
• The chaperone activity of HtrA is the primary driver of host cell binding for C. jejuni, underscoring its importance in the initial stages of infection.