Increase in secreted airway mucins and partial Muc5b STAT6/FoxA2 regulation during Pneumocystis primary infection

Area of Science:

• Pulmonary Medicine
• Microbiology
• Immunology

Background:

• Airway mucus responses to infections influence chronic lung disease progression and respiratory infection severity.
• Pneumocystis is a common subclinical infection in infants, linked to severe lung diseases and increased mortality.
• Pneumocystis infection is associated with elevated mucin 5AC (MUC5AC) in infant lungs, suggesting a role in allergic inflammation.

Purpose of the Study:

• To investigate mucus progression and MUC5B expression during Pneumocystis infection.
• To explore the potential for pharmacologic modulation of mucus via the STAT6/FoxA2 pathway during Pneumocystis infection.

Main Methods:

• Measurement of MUC5B and Pneumocystis in infant lungs.
• Experimental primary Pneumocystis infection in immunocompetent rats.
• Assessment of mucin levels and the effect of Kaempferol (JAK/STAT6 inhibitor) on the STAT6/FoxA2 pathway.

Main Results:

• Pneumocystis infection was associated with increased MUC5B in infant lungs.
• Muc5b expression increased earlier and more abundantly than Muc5ac during experimental infection, suggesting an acute defense response.
• Elevated Muc5ac levels indicated an ongoing allergic, Th2 lymphocyte-type response during primary Pneumocystis infection.
• Kaempferol partially reversed Muc5b stimulation, indicating limited potential for STAT6-FoxA2 pathway modulation.

Conclusions:

• Pneumocystis infection elicits distinct MUC5B and MUC5AC responses in the airways.
• Mucus production during Pneumocystis infection may involve both acute defense and allergic pathways.
• Pharmacologic inhibition of the STAT6-FoxA2 pathway shows limited efficacy in modulating mucus during Pneumocystis infection.