Metabolic reprogramming and dysregulated IL-17 production impairs CD4 T cell function post sepsis.

Sepsis survivors are at high risk for infection-related rehospitalization and mortality for years following the resolution of the acute septic event. These infection-causing microorganisms generally do not cause disease in immunocompetent hosts, suggesting that the post-septic immune response is compromised. Given the importance of CD4 T cells in the development of long-lasting protective immunity, we analyzed their post-septic function. Here we showed that sepsis induced chronic increased and non-specific production of IL-17 by CD4 T cells, resulting in the inability to mount an effective immune response to a secondary pneumonia challenge. Altered cell function was associated with metabolic reprogramming, characterized by mitochondrial dysfunction and increased glycolysis. This metabolic reprogramming began during the acute septic event and persisted long after sepsis had resolved. Our findings reveal cell metabolism as a potential therapeutic target. Given the critical role of cell metabolism in the physiological and pathophysiological processes of immune cells, these findings reveal a potential new therapeutic target to help mitigate sepsis survivors' susceptibility to secondary infections.

3D Culture Analysis of Cancer Cell Adherence to Ex Vivo Lung Microexplants.

Ex vivo 3D culture of human tissue explants addresses many limitations of traditional monolayer cell culture techniques, namely the lack of cellular heterogeneity and absence of 3D intercellular spatial relationships, but presents challenges with regard to repeatability due to the difficulty of acquiring multiple tissue samples from the same donor. In this study, we used a cryopreserved bank of human lung microexplants , ~1 mm3 fragments of peripheral lung from donors undergoing lung resection surgery, and a liquid-like-solid (LLS) 3D culture matrix to describe a method for the analysis of non-small cell lung cancer (NSCLC) adhesion to human lung tissue. H226 (squamous cell carcinoma), H441 (lung adenocarcinoma), and H460 (large cell carcinoma) cell lines were co-cultured with lung microexplants. Confocal fluorescence microscopy was used to visualize the adherence of each cell line to lung microexplants. Adherent cancer cells were quantified following filtration of non-adherent cells, digestion of cultured microexplants, and flow cytometry. This method was used to evaluate the role of integrins in cancer cell adherence. A statistically significant decrease in the adherence of H460 cells to lung microexplants was observed when anti-integrins were administered to H460 cells prior to co-culture with lung microexplants.