Arthropathic properties of cell wall polymers from normal flora bacteria

Area of Science:

• Microbiology
• Immunology
• Rheumatology

Background:

• Bacterial cell walls contain peptidoglycan-polysaccharide (PG-PS) structures.
• The role of PG-PS from various bacteria in inducing joint inflammation is not fully understood.

Purpose of the Study:

• To investigate the arthritogenic potential of PG-PS fragments from different bacterial species.
• To compare the inflammatory responses induced by PG-PS from group A and D streptococci, normal flora, and archaeal pseudomurein-PS.

Main Methods:

• Purification of PG-PS and pseudomurein-PS fragments from bacterial cell walls, minimizing autolytic activity.
• Intraarticular and intraperitoneal injection of purified fragments into rats to induce arthritis.
• Assessment of acute and chronic joint inflammation and disease progression.

Main Results:

• All tested PG-PS fragments induced acute inflammation upon intraarticular injection.
• Intraperitoneal injection revealed varying arthritic responses: group D streptococcal PG-PS induced severe acute arthritis evolving into chronic disease that subsided by 60 days.
• Group A streptococcal PG-PS induced severe acute arthritis progressing to chronic erosive joint disease active after 128 days.
• PG-PS from normal flora bacteria (P. acnes, Peptostreptococcus productus) induced a spectrum of acute and chronic arthritis.
• Pseudomurein-PS fragments showed significantly lower or no arthritic activity, highlighting the importance of the PG moiety.

Conclusions:

• Bacterial PG-PS structures are potent inducers of arthritis in a rat model.
• The specific structure of PG-PS determines the severity and chronicity of the induced joint disease.
• Normal flora bacteria possess PG-PS with the potential to cause a range of arthritic conditions, from transient acute inflammation to chronic erosive joint disease.