TNF and chronic obstructive pulmonary disease: The level of miR-7 was significantly increased in exosomes derived from COPD mice and in lung tissue macrophagesCOPD-exosomes induced an inflammatory response in the lungs of control mice. Lung tissue macrophages showed a shift towards M1 polarization. miR-7 inhibitor blocked M1 polarization of macrophages and reduced IL-6 and TNF-α secretion.