Matrix metalloproteinases (MMPs) certainly are a family of proteolytic enzymes that have a number of important physiological roles including remodelling of the BMS-790052 extracellular matrix facilitating cell migration cleaving cytokines and activating defensins. is discussed. Evidence from both clinical studies and animal models showing that stromal and inflammatory cell MMP expression leads to immunopathology is examined and the mechanisms by which excess MMP activity may be targeted to improve clinical outcomes are discussed. is one of the most successful human pathogens of all time and remains a global health crisis. ECM destruction is fundamental to the success of since it allows cavitation and thereby creates an immunoprivileged site within which the organism can proliferate and then BMS-790052 spread to new hosts.112 The reduced immune surveillance of the cavity is demonstrated by the ability of less virulent pathogens such as to occupy a pre‐existing pulmonary cavity. However the ability to create a cavity in previously normal lung distinguishes from these opportunist infections. If infects organs other than the lung it will generally reach a natural dead end eliminating its sponsor and failing woefully to pass on to a fresh one. Remarkably the mechanisms where it causes lung destruction are understood badly. As collagen and elastin should be degraded to permit cavity development MMPs will tend to be mixed up in pathology of TB. Pet research Guinea pigs present a comparatively good style of human being TB with granuloma morphology that’s similar to human being Muc1 disease but cavitary disease hardly ever develops. Water soluble small fraction of can boost collagenase secretion by guinea pig macrophages 113 but even more extensive evaluation of MMP activity in guinea pig TB is not undertaken. Mice certainly are a very useful style of immunity to leads to increased degrees of MMP‐2 and MMP‐9 in contaminated cells76 and disease of murine macrophages increases MMP‐9 secretion.77 Broad spectrum MMP inhibition in a mouse model of TB led to more rapid disease progression and a deficiency in IL‐1 and IL‐2 secretion with a relative excess of IL‐4 demonstrating a deviation in the BMS-790052 immune response to a Th2 profile.78 In another murine study MMP inhibition was reported to lead to reduced bloodborne with smaller granulomas less cell recruitment and more collagen deposition.79 This suggests that MMP activity may contribute to mycobacterial dissemination by facilitating erosion from the alveolus. However the lack of specificity of BB?\94 the MMP inhibitor used in these two studies makes interpretation difficult. BB‐94 also inhibits members of the ADAM family including ADAM‐17 (TNF‐α cleaving enzyme TACE) so the deviated immune response may be due to inhibition of TNF‐α release which is vital to an effective immune response to infected human macrophages MMP‐1 and ‐7 were most potently upregulated.86 The induction of these specific MMPs may drive matrix destruction as MMP‐1 degrades type I collagen7 and MMP‐7 is a potent elastase.109 MMP‐9 gene expression and secretion was unchanged showing that MMP regulation differs between human cell lines undifferentiated monocytes and macrophages. This suggests that MMP‐9 expression may occur at specific phases of granuloma BMS-790052 development. MMP‐1 and ‐7 were expressed in caseating granulomas of patients with active culture proven TB but not in control patients. Airway epithelial cells were also strongly immunoreactive for MMP‐1 showing that stromal cells may contribute to tissue destruction (fig 1?1).87 In culture epithelial cell MMP‐1 expression is driven by a monocyte dependent network. therefore drives a matrix degrading phenotype both by direct infection of macrophages and by an intercellular network that increases MMP secretion by epithelial cells (fig 2?2). Figure 1?Pulmonary epithelial cells BMS-790052 express MMP‐1 in patients with tuberculosis. MMP‐1 immunoreactivity is brown against the blue counterstain. In uninfected lung pulmonary epithelial cells do not express MMP‐1 (left panel). … Figure 2?Schematic representation of (MTb) driven tissue destruction. MTb infection of monocytes/macrophages increases MMP‐1 and MMP‐7 gene expression and secretion. No compensatory increase in secretion … MMPs as therapeutic targets The data outlined above implicate excess MMP activity in the pathogenesis of COPD ARDS sarcoidosis and TB. It therefore follows that modulating MMP activity may reduce immunopathology. The initial interest in.