Mice deficient in the enzyme MMP7, that cleaves prepro-$\alpha$-defensin to the active $\alpha$-defensin, show an increased susceptibility to the enteric pathogen, Salmonella typhimurium. The cell type in the gastrointestinal (GI) epithelium most likely to express the highest levels of MMP7 is:
A) Goblet cells
B) Paneth cells
C) M cells
D) GI-resident macrophages
E) Intraepithelial lymphocytes

Question

Quizplus · Accepted Answer

Paneth cells are known to express high levels of MMP7 in the GI epithelium. They are specialized intestinal epithelial cells that produce and secrete antimicrobial peptides including defensins, lysozyme and phospholipase A2. MMP7 is important for the activation of pro-defensins that are secreted by Paneth cells, thereby providing protection against microbial invasion in the gut. Mice deficient in MMP7 have reduced processing of pro-defensins to active defensins, leading to increased susceptibility to Salmonella typhimurium infection.

Mice Deficient in the Enzyme MMP7, That Cleaves Prepro- α\alphaα -Defensin to the Active

Mice Deficient in the Enzyme MMP7, That Cleaves Prepro- $\alpha$ -Defensin to the Active