SLPI (green) enters the nucleus (red) of monocytes and competes with NF-κB for binding to gene promoters.
Organs such as the lung that are continuously exposed to inhaled microbes must be carefully guarded against excessive inflammation. A new study by Taggart and colleagues on
page 1659 shows that a protease inhibitor that is produced in the airways helps subdue lung inflammation by shutting down the pro-inflammatory transcription factor NF-κB, both in the cytoplasm and the nucleus.One way the lung avoids inflammation-induced collateral damage is by producing protease inhibitors, such as SLPI (secretory leukocyte protease inhibitor). SLPI is produced by mucosal epithelial cells and inactivates potentially damaging enzymes, such as neutrophil elastase, that are produced by immune cells to help kill invading microbes.
But SLPI's protective function is not limited to defusing dangerous proteases. SLPI is also a potent antimicrobial peptide (akin to defensins) and an...
