Lung microvascular occlusion by platelet-rich neutrophil-platelet aggregates promotes cigarette smoke–induced severe flu
Tomasz W. Kaminski, Tomasz Brzoska, Xiuying Li, Ravi Vats, Omika Katoch, Rikesh K. Dubey, Kamal Bagale, Simon C. Watkins, Bryan J. McVerry, Tirthadipa Pradhan-Sundd, Lianghui Zhang, Keven M. Robinson, Toru Nyunoya, Prithu Sundd
Tomasz W. Kaminski, Tomasz Brzoska, Xiuying Li, Ravi Vats, Omika Katoch, Rikesh K. Dubey, Kamal Bagale, Simon C. Watkins, Bryan J. McVerry, Tirthadipa Pradhan-Sundd, Lianghui Zhang, Keven M. Robinson, Toru Nyunoya, Prithu Sundd
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Research Article Infectious disease Pulmonology

Lung microvascular occlusion by platelet-rich neutrophil-platelet aggregates promotes cigarette smoke–induced severe flu

Abstract

Cigarette smoking is associated with a higher risk of ICU admissions among patients with flu. However, the etiological mechanism by which cigarette smoke (CS) exacerbates flu remains poorly understood. Here, we show that a mild dose of influenza A virus promotes a severe lung injury in mice preexposed to CS but not room air for 4 weeks. Real-time intravital (in vivo) lung imaging revealed that the development of acute severe respiratory dysfunction in CS- and flu-exposed mice was associated with the accumulation of platelet-rich neutrophil-platelet aggregates (NPAs) in the lung microcirculation within 2 days following flu infection. These platelet-rich NPAs formed in situ and grew larger over time to occlude the lung microvasculature, leading to the development of pulmonary ischemia followed by the infiltration of NPAs and vascular leakage into the alveolar air space. These findings suggest, for the first time to our knowledge, that an acute onset of platelet-driven thrombo-inflammatory response in the lung contributes to the development of CS-induced severe flu.

Authors

Tomasz W. Kaminski, Tomasz Brzoska, Xiuying Li, Ravi Vats, Omika Katoch, Rikesh K. Dubey, Kamal Bagale, Simon C. Watkins, Bryan J. McVerry, Tirthadipa Pradhan-Sundd, Lianghui Zhang, Keven M. Robinson, Toru Nyunoya, Prithu Sundd

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Figure 4

Platelet-rich NPAs promote severe pulmonary ischemia in CS+Flu mice.

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Platelet-rich NPAs promote severe pulmonary ischemia in CS+Flu mice. Mic...
Mice were exposed to CS or RA for 4 weeks, followed by inoculation with flu, and qFILM was used to assess thrombo-inflammation in the lung at 4 days after infection. Microcirculation (pseudocolored purple), neutrophils (red), and platelets (pseudo-colored green). (A) Cropped qFILM images of the same FOV in the lung of a CS+Flu mouse shown at 4 different time points. Four neutrophils decorated with platelets crawl intravascularly (direction shown by arrows) over 9 minutes to form an NPA, which occludes a pulmonary microvessel (purple vascular dye disappears in the dashed ellipse). Time points relative to the first frame at 0 seconds. Refer to Supplemental Video 9. (B) Three representative qFILM images showing occlusion of lung microvessels (lack of blood flow evident by the absence of purple fluorescence in the microvessels marked with dotted lines). (C) Representative qFILM images of the lung of RA+Flu (top row) and CS+Flu (bottom row) mouse showing ischemic areas (dark regions without purple vascular dye). NPAs marked by arrowheads. Images in the right column show only the vascular dye (purple) channel of the respective 3-color images in the left column. Scale bars: 20 µm. qFILM data was analyzed to compare (D) number of ischemic areas per field of view (FOV), (E) percent FOVs with ischemic areas, and (F) size of ischemic areas in the lung of RA+Flu and CS+Flu mice. Data in D and F are shown as mean ± SEM and compared using Students’ t test. Data in E are shown as percentages and compared using χ2 distribution test. n = 5 mice per group and ~6–8 FOVs per mouse. *P < 0.05, **P < 0.01, ***P < 0.001. FOV size, 6,400 µm2.