Multi-Functional MPT Protein as a Therapeutic Agent against Mycobacterium tuberculosis

Abstract

Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB), avoids the host immune system through its virulence factors. MPT63 and MPT64 are the virulence factors secreted by MTB which regulate host proteins for the survival and proliferation of MTB in the host. Here, we found that MPT63 bound directly with TBK1 and p47phox, whereas MPT64 interacted with TBK1 and HK2. We constructed a MPT63/64-derived multifunctional recombinant protein (rMPT) that was able to interact with TBK1, p47phox, or HK2. rMPT was shown to regulate IFN-β levels and increase inflammation and concentration of reactive oxygen species (ROS), while targeting macrophages and killing MTB, both in vitro and in vivo. Furthermore, the identification of the role of rMPT against MTB was achieved via vaccination in a mouse model. Taken together, we here present rMPT, which, by regulating important immune signaling systems, can be considered an effective vaccine or therapeutic agent against MTB.

Discovery of Mycobacterium tuberculosis Rv3364c-Derived Small Molecules as Potential Therapeutic Agents to Target SNX9 for Sepsis

“…Next, to investigate the role of the SNX9-interacted Rv3364c peptide ( 12 WLVSKF 17 ) in the TLR-mediated inflammatory signaling pathway, − we examined whether the Tat-Rv3364c peptide, Tat-WLVSKF , inhibits the inflammatory cytokine production induced by LPS/TLR4. As shown in Figure C, the TLR4-mediated production of inflammatory cytokines was significantly attenuated by Tat-WLVSKF in SNX9 +/+ but not in SNX9 –/– macrophages.…”

“…MPT63 interacts with TBK1 and p47phox, and MPT64 interacts with TBK1 and HK2. rMPT has been shown to regulate the IFN-β levels and increase concentrations of inflammation and ROS, while simultaneously targeting macrophages and killing MTB in vitro and in vivo . Furthermore, the Rv3364c protein binds to plasma membrane-associated serine protease cathepsin G, inhibiting its enzymatic activity and the downstream activation of caspase-1-dependent apoptosis in macrophages; thus, MTB prevents macrophage pyroptosis by cytoplasmic surveillance in a protein-dependent manner .…”

“…rMPT has been shown to regulate the IFN-β levels and increase concentrations of inflammation and ROS, while simultaneously targeting macrophages and killing MTB in vitro and in vivo. 3 Furthermore, the Rv3364c protein binds to plasma membrane-associated serine protease cathepsin G, inhibiting its enzymatic activity and the downstream activation of caspase-1-dependent apoptosis in macrophages; thus, MTB prevents macrophage pyroptosis by cytoplasmic surveillance in a protein-dependent manner. 1 We found that the Rv3364c protein interacts with SNX9, which has an SNX-PX domain that allows its association with a range of phosphoinositides and recruits dynamin2 oligomers in the plasma membrane, where it coordinates the actin polymerization and vesicle release, 19 shares an Src homology 3 domain that allows its interaction with proline-rich proteins, 24 and contributes the BAR domain for dimerization in shaping the membrane curvature.…”

“…Multiple effector proteins secreted by Mycobacterium tuberculosis (MTB) may modulate host innate immunity by directing sophisticated systems involved in multiple host defense mechanisms such as toll-like receptors (TLRs), reactive oxygen species (ROS), and inflammatory responses. − Growing evidence supports the importance of MTB antigens from host–pathogen interactions in the development of vaccines, diagnostic methods, and therapeutics for infectious diseases including tuberculosis and sepsis. − MTB Rv3364c is one of the highly expressed proteins in the culture supernatant and lysates of MTB and macrophages . The Rv3364c gene contains the Roadblock/LC7 domain and is associated with the eukaryotic outer/inner flagellar dynein and cytoplasmic dynein in Myxococcus xanthus; it can have a structural or regulatory role .…”

Detection of Specific Antibodies Using Mpt83-Mpt63 Fusion Protein in Patients With Destructive Pulmonary Tuberculosis

“…In particular, serological tests for determining antibodies to MBT antigens MPT63, MPT64 [16], and MPT83 [17,18] have a good prospect for widespread use.…”