MFN2 and idiopathic pulmonary fibrosis: Although it is technically difficult to access the role of mitochondrial fusion proteins MFN1 and MFN2 in regulating lipid metabolism in human AEC2 cells from healthy and IPF lungs, in this study we provide evidence that MFN1 and MFN2 regulate lipid metabolism in murine AEC2 cells, which has important ramifications for surfactant lipid production in these cells and importantly for the development of lung fibrosis.