Myeloperoxidase Deficiency Alters the Process of the Regulated Cell Death of Polymorphonuclear Neutrophils

Zhike Erfang Alleviates MRSA-Induced Pneumonia by Inhibiting TRAF6 and Activating NLRP3 Inflammatory Body

Purpose

The therapeutic effects of Zhike Erfang in modulating the cellular responses and immune microenvironment associated with MRSA-induced acute lung injury remain unclear. This study aims to elucidate the potential mechanisms by which Zhike Erfang mitigate the cellular and molecular effects of MRSA in a laboratory model.

Patients and Methods

A mouse model of acute lung injury was established using heat-inactivated MRSA. Lung tissue and bronchoalveolar lavage fluid were collected for analysis. Macrophages were pretreated with Zhike Erfang for 30 minutes before exposure to heat-inactivated MRSA for 24 hours. Protein expressions of TRAF6, iNOS, TNF-α, IL-1β, NLRP3, and caspase-1 in lung tissues were quantified using Western blot. The content of LDH was detected by the lactate dehydrogenase cytotoxicity test kit.

Results

Zhike Erfang significantly reduced the expression of iNOS, LDH, TNF-α, IL-1β, NLRP3, and caspase-1 in a dose-dependent manner in lung tissues from the MRSA model. Zhike Erfang inhibited the expression of TRAF6.

Conclusion

Zhike Erfang can alleviate pneumonia caused by MRSA by inhibiting TRAF6 and inducing NLRP3 inflammatory body activation.

Functional neutrophil disorders: Chronic granulomatous disease and beyond

Since their description by Metchnikoff in 1905, phagocytes have been increasingly recognized to be the entities that traffic to sites of infection and inflammation, engulf and kill infecting organisms, and clear out apoptotic debris all the while making antigens available and accessible to the lymphoid organs for future use. Therefore, phagocytes provide the gateway and the first check in host protection and immune response. Disorders in killing and chemotaxis lead not only to infection susceptibility, but also to autoimmunity. We aim to describe chronic granulomatous disease and the leukocyte adhesion deficiencies as well as myeloperoxidase deficiency and G6PD deficiency as paradigms of critical pathways.

Non-Canonical Functions of Myeloperoxidase in Immune Regulation, Tissue Inflammation and Cancer

Myeloperoxidase (MPO) is one of the most abundantly expressed proteins in neutrophils. It serves as a critical component of the antimicrobial defense system, facilitating microbial killing via generation of reactive oxygen species (ROS). Interestingly, emerging evidence indicates that in addition to the well-recognized canonical antimicrobial function of MPO, it can directly or indirectly impact immune cells and tissue responses in homeostatic and disease states. Here, we highlight the emerging non-canonical functions of MPO, including its impact on neutrophil longevity, activation and trafficking in inflammation, its interactions with other immune cells, and how these interactions shape disease outcomes. We further discuss MPO interactions with barrier forming endothelial and epithelial cells, specialized cells of the central nervous system (CNS) and its involvement in cancer progression. Such diverse function and the MPO association with numerous inflammatory disorders make it an attractive target for therapies aimed at resolving inflammation and limiting inflammation-associated tissue damage. However, while considering MPO inhibition as a potential therapy, one must account for the diverse impact of MPO activity on various cellular compartments both in health and disease.