Sentence:  In general, <WSD>MMP</WSD> expression can be downregulated through a TGF-β-inhibitory element (TIE), which is present in the promoters of <WSD>MMP</WSD>-1, <WSD>MMP</WSD>-3, <WSD>MMP</WSD>-9, and <WSD>MMP</WSD>-13. 
Meaning of the word marked with <WSD> tags:  Matrix metalloproteinase