Pulmonary IL-1β expression in early life causes permanent changes in lung structure and function in adulthood

Area of Science:

• Pulmonary Medicine
• Developmental Biology
• Immunology

Background:

• Neonatal lung inflammation from factors like chorioamnionitis and infection has unknown long-term effects.
• Infant pulmonary inflammation can impact lung development during critical saccular to alveolar stages.

Purpose of the Study:

• To investigate the long-term consequences of early-life pulmonary inflammation on adult lung structure and function.
• To determine if IL-1β-induced inflammation during specific lung development stages leads to chronic lung disease.

Main Methods:

• Utilized a doxycycline-inducible transgenic mouse model to induce IL-1β expression in pulmonary epithelium on postnatal days 0, 0.5, and 1.
• Assessed lung structure, inflammation, and airway hyperresponsiveness in adulthood (PN21-PN84).
• Measured inflammatory cell counts, alveolar morphology, goblet cell hyperplasia, CLCA3 expression, methacholine response, lymphoid follicle presence, and CXCL13 levels.

Main Results:

• Early IL-1β expression led to transient inflammation (macrophages, neutrophils) by PN21, which resolved by PN42.
• Permanent structural changes, including larger alveoli and thickened alveolar walls with impaired septation, persisted from PN21 to PN84.
• Adult mice exhibited goblet cell hyperplasia, increased CLCA3 protein, heightened airway reactivity, lymphoid follicle formation, and elevated CXCL13 levels.

Conclusions:

• IL-1β-induced pulmonary inflammation in early life results in chronic lung disease in adulthood.
• Early inflammation permanently alters lung structure and function, persisting even after inflammation subsides.
• Findings highlight the critical impact of early-life inflammatory insults on long-term respiratory health.