MCAM and chronic lung disease: By controlling HIF-1α activation in PASMCs under hypoxia or possibly during chronic lung diseases, which may lower local O2 tension, CD146-mediated NF-kB expands its well-established proinflammatory function, because HIF-1α-dependent hypoxic response is critical for providing PASMCs and maybe other types of pulmonary cells undergoing hypoxia with sufficient energy supplies and allows them to resist cell death and apoptosis.