Research ArticleLUNG INJURY

Neutrophil transfer of miR-223 to lung epithelial cells dampens acute lung injury in mice

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Science Translational Medicine  20 Sep 2017:
Vol. 9, Issue 408, eaah5360
DOI: 10.1126/scitranslmed.aah5360

Starting an intercellular conversation

In a new study, Neudecker et al. show that transfer of microRNA-223 (miR-223) from neutrophils to lung alveoli helps to dampen lung inflammation and promotes the resolution of ventilator-induced lung injury in mice. The authors suggest that neutrophils secrete microRNAs in microvesicles that are then taken up by alveolar epithelial cells. They show that miR-223–deficient mice are prone to lung injury, whereas overexpression of miR-223 is protective.


Intercellular transfer of microRNAs can mediate communication between critical effector cells. We hypothesized that transfer of neutrophil-derived microRNAs to pulmonary epithelial cells could alter mucosal gene expression during acute lung injury. Pulmonary-epithelial microRNA profiling during coculture of alveolar epithelial cells with polymorphonuclear neutrophils (PMNs) revealed a selective increase in lung epithelial cell expression of microRNA-223 (miR-223). Analysis of PMN-derived supernatants showed activation-dependent release of miR-223 and subsequent transfer to alveolar epithelial cells during coculture in vitro or after ventilator-induced acute lung injury in mice. Genetic studies indicated that miR-223 deficiency was associated with severe lung inflammation, whereas pulmonary overexpression of miR-223 in mice resulted in protection during acute lung injury induced by mechanical ventilation or by infection with Staphylococcus aureus. Studies of putative miR-223 gene targets implicated repression of poly(adenosine diphosphate–ribose) polymerase–1 (PARP-1) in the miR-223–dependent attenuation of lung inflammation. Together, these findings suggest that intercellular transfer of miR-223 from neutrophils to pulmonary epithelial cells may dampen acute lung injury through repression of PARP-1.

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