Abstract Background Cryptococcus neoformans, the etiological agent of cryptococcosis, can survive and replicate within host immune cells, contributing to development of cryptococcal meningitis. Within the lung, C. neoformans interacts with innate immune subsets, including macrophages and dendritic cells (DCs). Our previous work demonstrated that Ly6c– monocyte-like macrophages restrict fungal proliferation, whereas CD11b+ DCs promote fungal growth. Transcriptomic profiling revealed differential expression of MHC class I gene H2-K1, Calreticulin (Calr), and metabolic genes. Therefore, we hypothesized that H2-K1 and metabolic pathways modulate the intracellular fungal fate within pulmonary macrophages and DCs. Methods H2-K1 expression was knocked down using siRNA in J774 macrophages and GM-CSF-induced bone marrow-derived DCs (BMDCs). Antifungal activity was determined by CFU enumeration. Phagocytic uptake, cathepsin B activity, Nos2 expression and reactive oxygen species (ROS) production were quantified by flow cytometry. Metabolic dependencies were evaluated using SCENITH assay. Results H2-K1 KD in J774 cells significantly reduced antifungal activity compared to controls. H2-K1 knockdown also decreased Calr gene expression, suggesting H2-k1 has downstream effects in the pathway. H2-K1 silencing did not significantly alter phagocytic uptake, cathepsin B activity, or Nos2 expression. However, ROS production was significantly reduced in H2-K1 KD J774 cells, indicating impaired responses. SCENITH analysis revealed that antifungal macrophages shift their metabolism toward glucose oxidation for ATP generation, which is important for antifungal activity. Conclusion These findings indicate that metabolic reprogramming is critical for effective antifungal responses. Our data provide a foundation for future studies aimed at targeting host immune and metabolic pathways to enhance antifungal immunity.
Nair et al. (Thu,) studied this question.