Visualizing a lung neutrophil-platelet immunothrombosis cascade during sepsis in mice

Sepsis is an immune paradox where host defence is necessary for survival but also contributes to organ damage and death. Using lung intravital microscopy we defined an immunothrombosis cascade of neutrophil and platelets in the microcirculation in response to E. coli sepsis. Neutrophil cathelicidin localized neutrophils to E. coli and initiated founder immunothrombi via formyl-peptide receptors. Immunothrombi captured vascular bacteria and cathelicidin enabled antimicrobial activities in platelets. Blocking cathelicidin prevented the immunothrombosis cascade and attenuated early sepsis death but resulted in delayed death with uncontrolled infection. LTB4 amplified the immunothrombi and inhibiting it diminished detrimental immunothrombi while preserving host defense, thus representing a discrete inflection point of sepsis disease progression. Therefore, targeting the immunothrombi cascade can mitigate immunopathology without suppressing host defence during sepsis.
, , , # Visualizing a lung neutrophil-platelet immunothrombosis cascade during sepsis in mice

Dataset DOI: [10.5061/dryad.0k6djhbfz](https://doi.org/10.5061/dryad.0k6djhbfz)

## Description of the data and file structure

Neutrophil behavior was characterized using Imaris software (Oxford Instruments, v10.1). In brief, surfaces were applied to corresponding channels with absolute intensity thresholding. Voxels <40 were filtered out for neutrophils, and <10 for platelets, and endothelium. Spots were used for tracking bacteria. Neutrophil cellular characteristics, including area, sphericity (polarization), platelet surface overlap, distance to *E. coli,* etc., were measured.

2D video imaging was used for cellular behavioral analysis in the pulmonary microvasculature. Imaris surface and track parameters of neutrophils were exported with specific raw values into Microsoft Excel. Extracted raw values of morphometric and kinematic parameters of interest were exported into .csv files and loaded in...,