Macrophage-derived apoptotic bodies promote the proliferation of the recipient cells via shuttling microRNA-221/222.

Bacterial pneumonia is a common and serious clinical entity. Alveolar epithelial cells and alveolar macrophages are the first line of defense in the innate immunity against bacterial pathogens. Epithelial cells are known to release chemokines/cytokines that recruit and activate phagocytic cells. However, the signals sent from alveolar macrophages back to the lung epithelial cells remain largely unexplored. We found that LPS, a well-recognized stimulator derived from gram-negative (G