Cellulose nanocrystals modulate alveolar macrophage phenotype and phagocytic function

Area of Science:

• Biomaterials Science
• Toxicology
• Immunology

Background:

• Nanocellulose, a promising biomaterial, faces increasing industrial use, raising concerns about occupational exposure and potential health risks.
• Limited knowledge exists on nanocellulose's health effects, particularly the mechanisms behind lung inflammation induced by exposure.
• Alveolar macrophages are crucial for lung particle clearance and their function may be compromised by particle exposure.

Purpose of the Study:

• To investigate the uptake of cellulose nanocrystals (CNC) by alveolar macrophages.
• To determine the effects of CNC on macrophage polarization and biological function.
• To elucidate the mechanisms by which CNC may influence inflammatory responses in the lung.

Main Methods:

• Investigated CNC uptake in alveolar macrophages.
• Assessed the impact of CNC on macrophage polarization markers (M1/M2 phenotypes) in the presence of specific activators (LPS/IFNG, IL4/IL13).
• Evaluated changes in cytokine secretion, chemokine release, and phagocytic activity following CNC exposure.

Main Results:

• CNC uptake by alveolar macrophages was confirmed.
• CNC exposure, particularly with macrophage activators, enhanced M1 polarization markers and pro-inflammatory cytokine/chemokine secretion.
• CNC exposure reduced M2 markers and significantly altered the function of activated macrophages, including cytokine burst and phagocytosis.

Conclusions:

• Cellulose nanocrystal exposure can dysregulate alveolar macrophage activation and function.
• These alterations in macrophage behavior are critical and may contribute to inflammatory responses in the lung.
• Further research is needed to fully understand the toxicological implications of nanocellulose occupational exposure.