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 3

In situ formation of large platelet-rich NPAs promotes pulmonary thrombo-inflammation in CS+Flu mice.

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In situ formation of large platelet-rich NPAs promotes pulmonary thrombo...
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 (pseudocolored green). (A and B) qFILM images of 2 separate field of views (FOVs) in the lung of CS+Flu mice at four different time points. (A) A neutrophil bound to platelets (arrowhead) crawls intravascularly to join a large NPA (dashed ellipse). Refer to Supplemental Video 7. Arrow denotes direction of blood flow. Scale bar: 25 µm. (B) A neutrophil bound to platelets (arrowhead) crawls intravascularly to join an existing NPA (dashed ellipse). Scale bar: 20 µm. Refer to Supplemental Video 8. qFILM analysis revealed that (C) the number of neutrophils crawling toward a large NPA per FOV was significantly higher and (D) the crawling velocity of neutrophils was significantly lower in the lung microcirculation of CS+Flu than RA+Flu mice. (E) The crawling velocity of single neutrophils (without bound platelets) was not different from the neutrophils bound to platelets. qFILM images were analyzed to compare (F) number of NPAs per FOV and (G) size of NPAs in the lung of RA+Flu and CS+Flu mice. (H) Three representative qFILM images of platelet-rich NPAs in the lung microcirculation of CS+Flu mice. Scale bar: 10 μm (left) and 25 μm (middle and right). (I) Percent FOVs containing at least 1 platelet-rich NPA in the lung of RA+Flu and CS+Flu mice. FOV size ~8,600 µm2 (A) and ~4,300 µm2 (B). *P < 0.05, **P < 0.01. Data in C, D, and F are shown as mean ± SEM and compared using Students’ t test. n = 5 mice per group and ~6–8 FOVs per mouse (C–G and I).