# PM2.5 affected ciliary beat frequency of axonemes via the cyclic AMP-dependent protein kinase a pathway

## TL;DR

This study shows how fine particles in air pollution can change the beating of airway cilia, potentially leading to lung diseases.

## Contribution

The study identifies the cAMP-PKA pathway as a mechanism through which PM2.5 affects ciliary beat frequency.

## Key findings

- Low concentrations of PM2.5 increased ciliary beat frequency in short-term exposure.
- High concentrations and prolonged exposure to PM2.5 damaged cilia and increased disease risk.

## Abstract

Long-term inhalation of fine particulate matter (PM2.5) has been linked to the onset of various lung diseases. The mucociliary clearance system, acts as the primary host defense mechanism in the airways, with ciliary beat frequency (CBF) being a key parameter for assessing its functionality. The primary aim of this study was to demonstrate the impact of PM2.5 on CBF and to investigate the potential mechanisms by which PM2.5 induced changes in CBF through airway axonemes. Airway axonemes were extracted from bovine ciliated epithelium and treated with different concentrations of PM2.5in vitro for 10 min and 1 h to simulate short-term and prolonged exposures. Additionally, the pathway was examined using PKA activator (cAMP) and PKA inhibitor (PKI) on ciliary axonemes. The results revealed that PM2.5 stimulated CBF in airway axonemes via the cAMP-PKA pathway. Low concentrations and short-term exposure to PM2.5 stimulated CBF elevation, however, high concentration and prolonged exposure to PM2.5 might damage respiratory cilia, thereby increasing the risk of respiratory diseases.