Derepression of matrix metalloproteinase gene transcription and an emphysema-like phenotype in transcription factor Zbtb7c knockout mouse lungs

: Dysregulated matrix metalloproteinase (MMP) gene expression is a major cause of the degradation of lung tissue that is integral to emphysema pathogenesis. Cigarette smoking (CS) increases MMP gene expression, a major contributor to emphysema development. We previously reported that Zbtb7c is a transcriptional repressor of several Mmp genes (Mmps-8, -10, -13, and -16). Here, we show that Zbtb7c knockout mice have mild emphysema-like phenotypes, including alveolar wall destruction, enlarged alveoli, and upregulated Mmp genes. Alveolar size and Mmp gene expression in Zbtb7c-/- mouse lungs are increased more severely upon exposure to CS, compared to those of Zbtb7c+/+ mouse lungs. These observations suggest that Zbtb7c degradation or absence may contribute to the pathogenesis of emphysema.