Pilus- gonococcal variants. Evidence for multiple forms of piliation control

Area of Science:

• Microbiology
• Bacterial genetics
• Pathogenesis

Background:

• Neisseria gonorrhoeae (Gc) exhibits dynamic changes in piliation, a key factor in host cell adherence.
• Pilus expression influences gonococcal interactions with host cells, impacting infection.
• Understanding piliation regulation is crucial for deciphering gonococcal pathogenesis.

Purpose of the Study:

• To investigate the mechanisms underlying pilus-positive to pilus-negative transitions in Gc.
• To differentiate between DNA rearrangement-dependent and independent pathways of piliation changes.
• To explore the potential pathogenic advantages of reversible piliation changes.

Main Methods:

• Analysis of pilin gene DNA rearrangements in Gc.
• Phenotypic characterization of non-piliated Gc, including pilin subunit synthesis and mRNA presence.
• Comparison of reverting and non-reverting Gc populations.

Main Results:

• Pilus-positive to pilus-negative transitions involving DNA rearrangement result in an irreversible P-n phenotype.
• Non-piliated Gc without DNA rearrangement can revert to pilus-positive.
• Two distinct reverting phenotypes (P-rp- and P-rp+) were identified, differing in pilin subunit synthesis but both possessing pilin mRNA.
• These findings suggest both genetic rearrangement and post-transcriptional mechanisms regulate Gc piliation.

Conclusions:

• Multiple mechanisms regulate Gc piliation status, including pilin gene rearrangement and post-transcriptional control.
• Reversible changes in piliation may confer a pathogenic advantage by modulating host cell adherence.
• Further research into these regulatory pathways can inform strategies against gonococcal infections.