Mathematical Modelling of Neutrophil Responses to Aspergillus

Abstract Invasive aspergillosis is a dangerous infection commonly affecting immunocompromised patients. The spores of the fungal pathogen, Aspergillus, are found ubiquitously in the environment and are inhaled daily by all humans. These spores are cleared quickly and effectively healthy hosts without developing infection. On the other hand, patients with impaired immunity, can develop an invasive pneumonia with poor outcomes. Neutrophils are essential to the host defense against aspergillosis, both in direct fungal killing and as modulators of immunity against the pathogen. To better understand this role, we conducted a transcriptomic time series comparing the responses of human neutrophils to Aspergillus. Differential gene expression analysis as well as gene enrichment analysis indicated an up regulation of number of transcriptional markers and pathways including NFkB, NR4A, TNF, as well as neutrophil degranulation, cytokine-mediated signaling, chemokine signaling, and TREM1 signaling among others. Combining this data with known mechanisms and pathways from the literature, we built a mathematical model describing the intracellular pathways which determine the neutrophil’s response after detecting Aspergillus. Very few mathematical models have been built modeling intracellular mechanisms of a neutrophil and none that we know of which relates to the interaction between neutrophils and this organism. We intend to use our model to make predictions on the effects of altering different pathways within the cell. Moreover we intend to use this model in a larger systems model describing the immune system response to invasive pulmonary aspergillosis. Supported by: R01AI135128, U01EB024501, Keck Foundation Medical Research Grant 994413.