Fungal Aflatoxins Reduce Respiratory Mucosal Ciliary Function

Area of Science:

• Respiratory Medicine
• Mycology
• Cell Physiology

Background:

• Aflatoxins, mycotoxins from Aspergillus flavus, are implicated in respiratory infections.
• Aspergillus flavus is a significant cause of invasive aspergillosis.
• Respiratory pathogens often secrete toxins that compromise mucociliary immunity.

Purpose of the Study:

• To investigate the impact of acute aflatoxin exposure on human airway cell physiology.
• To determine the effects on ciliary beat frequency (CBF), intracellular calcium, and nitric oxide (NO) production.

Main Methods:

• Utilized air-liquid interface cultures of primary human sinonasal and bronchial cells.
• Measured ciliary beat frequency (CBF), intracellular calcium, and nitric oxide (NO).
• Assessed protein kinase C (PKC) activity using a fluorescent reporter in A549 cells.

Main Results:

• Aflatoxin exposure reduced baseline and stimulated CBF by 6-12%.
• Conditioned media from Aspergillus species reduced CBF, with effects blocked by anti-aflatoxin antibodies for A. flavus.
• AFB2 reduced NO production by approximately 50% and activated PKC.

Conclusions:

• Aflatoxins secreted by respiratory Aspergillus flavus can impair airway cilia motility and chemosensory functions.
• These effects may contribute to the pathogenesis of fungal airway diseases.
• PKC activation is involved in aflatoxin-induced CBF reduction, but calcium and NO changes are not the primary mechanism for CBF impairment, except for AFB2's effect on NO production.