Membrane-type-1 matrix metalloproteinase (MT1-MMP) belongs to a group of six membrane-bound MMPs and it is expressed on endothelium, myeloid cells and lymphocytes. It is thus an ectoenzyme cleaving cell-surface adhesion molecules. Shedding of
adhesion molecule CD44 by MT1-MMP renders the cells more motile 3. Cleavage of ICAM-1, on the other hand, is thought to regulate the transmigration process. In addition to adhesion molecules, MT1-MMP also cleaves and thus inactivates chemokines such as CCL7 and CXCL12 64. Overall, the sheddases importantly contribute to the extravasation process by trimming both adhesion molecules and chemokines. Most likely they also degrade extracellular matrix molecules facilitating leukocyte movement within Y-27632 in vivo the tissues. Manipulation of purinergic signaling provides a possibility to temper inflammation without interfering with the classical chemokine and cytokine Anti-infection Compound Library signals 39. The beneficial role of adenosine, a powerful inhibitor of inflammation and vascular
leakage, has been demonstrated in clinical settings by infusing it in ischemia-reperfusion injuries; however, due to the short half-life (<10 s) its clinical use is not feasible. Therefore, the generation of endogenous adenosine through the induction of CD73 provides an attractive alternative. IFN-β induces CD73 expression and enzymatic activity on endothelial cells but not on leukocytes or cancer cells and IFN-β has protective effects in animal models of acute PtdIns(3,4)P2 lung inflammation 46. Promising results have also very recently been reported in clinical trials of acute lung injury and acute respiratory distress syndrome, in which IFN-β significantly decreased the mortality (http://www.faronpharmaceuticals.com). IFN-β therapy also increases
levels of endothelial CD73 and soluble CD73 in the serum in multiple sclerosis patients, and these parameters associate with the clinical response 65. Thus, it may be envisioned that IFN-β-induced, CD73-mediated adenosine production contributes to the improved vascular barrier function and reduced leukocyte infiltration in several organs. Moreover, recent studies have demonstrated that TGF-β induces expression of CD73 on leukocytes, possibly providing an additional therapeutic approach to up-regulate CD73 for anti-inflammatory purposes from the leukocyte side as well 66. Statins also increase the expression and enzymatic activity of CD73; however, they act by inhibiting the endocytosis of CD73 without increasing protein synthesis. Therefore, statins may be beneficial only for short-term applications such ischemia-reperfusion injuries or for cardiac pre-conditioning. Clinical trials with statins targeting CD73 independently of their cholesterol-lowering effects have been recently completed (http://clinicaltrials.gov/).