Zinc metalloprotease-1 (Zmp1) from (based hostCpathogen model was used to study mycobacterial dissemination (TdM. by alveolar 511-09-1 IC50 macrophages, polymorphonuclear neutrophils and type 2 pneumocytes by phagocytosis (Smith, 2003). In most of the cases, the infection does not result in disease as the bacillus has evolved evasion strategies to live in balance with the immune response, thus remaining latent for G-CSF decades (Babalola, 2015). A hallmark of immune reaction to TB bacilli is the formation of granuloma, by which host attempts to contain the infection (Guirado and Schlesinger, 2013). The granuloma is an aggregate of various immune cells, such as, macrophages, dendritic cells, and lymphocytes whose function depends on 511-09-1 IC50 the cytokine environment generated due to TB infection (Ordway et al., 2006). Some of the infected cells undergo necrosis and create an acellular central zone where TB bacilli persist within granuloma. This necrotic zone eventually disintegrates in certain immunocompromised hosts, triggered by a mechanism still unknown, causing reactivation (Silva Miranda et al., 2012; Guirado and Schlesinger, 2013). A significant aspect of the pathogenesis of virulent mycobacteria, like have been implicated in either initial establishment of lung infections or extrapulmonary dissemination. To exemplify, ESAT-6 limits macrophage responses by inhibiting signaling from Toll-like receptor-2 (TLR-2) and causes phagosomal membrane lysis, thus helping establishment of infection, while HbhA, a glycoprotein, found on surface and also in culture filtrates, is not required for initial infection, but has possible role in dissemination to extrapulmonary regions (Pethe et al., 2001; de Jonge et al., 2007; Pathak et al., 2007). Yet other proteins, unique to mycobacteria genus, like PE25/PPE41 protein complex, has been shown to induce necrosis in macrophages and speculated to have a role in dissemination and disease reactivation (Tundup et al., 2014). An interesting group of secreted proteins is extracellular Zinc-metalloproteases. These have been documented to contribute to the virulence of pathogenic bacteria by a variety of mechanisms. Several of these are established exotoxins and virulence factors, such as metalloprotease from O1 serotype (Finkelstein and Hanne, 1982; Hase and Finkelstein, 1993) or enterotoxin from (Obiso et al., 1995). In local bacterial infections, such as by or (keratitis, dermatitis) or by (pneumonia), the secreted metalloproteases cause necrotic or hemorrhagic tissue damage through digestion of structural components of the ground substance, enhancing vascular permeability permitting bacterial dissemination (Miyoshi and Shinoda, 2000). Similarly, clostridial neurotoxins are Zinc-metalloproteases that act by specifically cleaving a synaptic vesicle membrane or the presynaptic plasma membrane protein (Hayashi et al., 1994). So far, there are evidences of three Zinc-metalloproteases from in the culture filtrate, namely, Rv2869 (Rip), Rv2467 (pepN) and Rv0198c (Zmp1). Rv2869 (Rip), a secretory metalloprotease has been shown to regulate intramembrane proteolysis and proteolytic degradation of anti-sigma substrates like RsdA controlling the SigD mediated transcriptional regulation in mycobacteria during stationary phase and hypoxia (Raman et al., 2004; Calamita et al., 2005) and thereby playing a role in mycobacterial virulence (Makinoshima and Glickman, 2005; Sklar et al., 2010). Rv0198c (Zmp1), supported by deletion mutant studies, was implicated in suppression of inflammasome activation by inhibiting caspase-1 activity and phagosome maturation, leading to decreased pathogen clearance suggesting a key role of Zmp1 during pathogenicity (Master et al., 2008; Johansen et al., 2011). In a recent study from our lab, we identified and characterized purified Zmp1 as a mycobacterial antigen that is secreted during granuloma-like stress conditions and generated Th2 cytokine microenvironment upon exogenous treatment of PBMCs, which was supported by recording specific and robust humoral response in a large cohort of TB patients (Vemula et al., 2016). Interestingly, the purified Zmp1 protein was earlier shown to cleave synthetically generated neuropeptides (Petrera et al., 2012). With Zmp1 reported as a virulence factor holding the properties of immunomodulation, high immunogenicity and proteolysis of synthetic neuropeptides, we further 511-09-1 IC50 extended the study on the other possible roles of Zmp1 in the pathogenesis of that exogenous (secretory) Zmp1 helped in dissemination of mycobacteria. With this study, along with the earlier observations from our laboratory and others, Zmp1 has emerged as a multi-faceted protein which can be further explored as either a vaccine candidate, biomarker or anti-mycobacterial target. Materials and Methods The cell lines used were Chinese Hamster Ovary (CHO) cell line and THP-1 Monocyte leukemia.