Urban particulate matter triggers lung inflammation via the ROS-MAPK-NF-κB signaling pathway

Area of Science:

• Environmental Health
• Toxicology
• Cell Biology

Background:

• Particulate matter (PM) is a significant risk factor for respiratory diseases.
• PM exposure triggers inflammation in lung tissues, but the precise molecular mechanisms remain unclear.

Purpose of the Study:

• To elucidate the molecular mechanisms underlying PM-induced lung inflammation.
• To investigate the role of reactive oxygen species (ROS) and specific signaling pathways in PM-induced airway inflammation.

Main Methods:

• Human bronchial epithelial cells (HBECs) and a C57 mice model were used to assess PM-induced inflammation.
• Intracellular ROS levels, oxidant stress markers (DHE, MDA, H2O2), inflammatory cell counts, and cytokine expression (IL-1β, IL-6, IL-8, MMP-9) were measured.
• Specific inhibitors were used to block MAPK and NF-κB pathways, and N-acetylcysteine (NAC) was employed to assess the role of oxidative stress.

Main Results:

• PM exposure increased pro-inflammatory cytokine expression (IL-1β, IL-6, IL-8, MMP-9) and cyclooxygenase-2 (COX-2) in a dose-dependent manner.
• PM induced ROS generation and activated MAPK (ERK, JNK, p38) and NF-κB pathways in HBECs.
• In vivo, PM exposure led to increased lung oxidant stress, inflammatory cell infiltration, and elevated inflammatory markers in bronchoalveolar lavage fluid (BALF), which were partially reversed by NAC.

Conclusions:

• PM exposure significantly enhances airway inflammation via ROS-mediated activation of MAPK and downstream NF-κB signaling pathways.
• Oxidative stress is identified as a critical regulator in PM-induced lung inflammation.
• The study elucidates the molecular mechanisms driving PM-induced lung inflammation.