In conclusion, we reveal a function for MFN1 and MFN2 in mediating lung fibrosis by regulating lipid metabolism in response to mitochondrial injury in AEC2 cells of the lung, supporting the mitochondrion as a critical signaling and metabolic hub in AEC2 cells, required to modulate and control AEC2 cellular adaptation to lung fibrosis. The gene discussed is MFN1; the disease is pulmonary fibrosis.