Livingston, A. | Search bioRxiv

bioRxiv2025

Plasma Membrane Damage by Environmental Materials Enhances Cell-Cell Fusion and Impairs Immune Functions of Macrophages

Macrophages are the most abundant phagocytes and play an essential role in host defense. Previous studies have shown that many environmental materials can activate macrophages and trigger inflammatory responses. However, whether these exposures alter macrophage function in host defense remains unclear. This study found that many environmental materials (such as carbon nanotubes, tungsten carbide [WC], and detergents) can damage the plasma membranes of macrophages. This damage leads to decreased reactive oxygen species (ROS) production and phagocytosis but elevated cell-cell fusion. In vivo, airway exposure to laundry detergent impaired the recruitment of macrophages and other myeloid cells to the lung and dramatically dampened protective TH1 and TH17 cell responses, leading to increased susceptibility to Candida infection in mice. Overall, our data indicate that exposure to environmental materials compromises macrophage membrane integrity and impairs host defense. These findings may aid in the development of effective preventive and therapeutic strategies.

immunology↗

bioRxiv2023

Unconventional Activation of IRE1 Enhances TH17 Responses and Promotes Neutrophilic Airway Inflammation

Treatment-refractory severe asthma manifests a neutrophilic phenotype associated with TH17 responses. Heightened unfolded protein responses (UPRs) are associated with the risk of asthma, including severe asthma. However, how UPRs participate in the deregulation of TH17 cells leading to this type of asthma remains elusive. In this study, we investigated the role of the UPR sensor IRE1 in TH17 cell function and neutrophilic airway inflammation. We found that IRE1 is induced in fungal asthma and is highly expressed in TH17 cells relative to naive CD4+ T cells. Cytokine (e.g. IL-23) signals induce the IRE1-XBP1s axis in a JAK2-dependent manner. This noncanonical activation of the IRE1-XBP1s pathway promotes UPRs and cytokine secretion by TH17 cells. Ern1 (encoding IRE1)-deficiency decreases the expression of ER stress factors and impairs the differentiation and cytokine secretion of TH17 cells. Genetic ablation of Ern1 leads to alleviated TH17 responses and airway neutrophilia in a Candida albicans asthma model. Consistently, IL-23 activates the JAK2-IRE1-XBP1s pathway in vivo and enhances TH17 responses and neutrophilic infiltration into the airway. Taken together, our data indicate that IRE1, noncanonically activated by cytokine signals, promotes neutrophilic airway inflammation through the UPR- mediated secretory function of TH17 cells. The findings provide a novel insight into the fundamental understanding of IRE1 in TH17-biased TH2-low asthma.

immunology↗