Mce4F Mycobacterium tuberculosis protein peptides can inhibit invasion of human cell lines

Abstract

This work was aimed at studying the Mycobacterium tuberculosis H37Rv Rv3494c protein, taking into account that it belongs to the mammalian cell entry family (mce) which is thought to have important functions in the disease's pathogenesis. The protein was characterized in silico; its presence on mycobacterial surface was confirmed by immunoelectron microscopy. High-activity binding peptides (HABPs) were identified by binding assays with (125)I; their ability to inhibit mycobacterial entry to two cell lines (U937 alveolar macrophages and A549 epithelial cells) was ascertained and their role in bacterial entry was confirmed by fluorescent microsphere internalization assay. This protein's predicted alpha-helix structure was confirmed by circular dichroism of its peptides. All HABPs inhibited mycobacterial entry to cells and that the 38379 peptide ((201)IDQAGPFLQAQIRAGGDIKSY(220)) had high binding ability and inhibited the mycobacterial entry to both cell lines assayed here. Rv3494c peptides 38370 ((21)LSVMAIFYLRLPATFGIGTY(40)), 38373 ((81)HMRLNSGTAIPSNVTATVRSY(100)) and 38379 ((201)IDQAGPFLQAQIRAGGDIKSY(220)) showed to be HABP and inhibited mycobacterial entry to A549 cells and peptide 38382 ((261)RPSFPALAASLANLGRVGVIY(280)) bind to U937 and inhibited the mycobacterial entry to this cell line; all of these sequences play an important role in cell line recognition and invasion, and may thus be considered in the search for prophylactic candidates against tuberculosis.

Rv2629 Overexpression Delays Mycobacterium smegmatis and Mycobacteria tuberculosis Entry into Log-Phase and Increases Pathogenicity of Mycobacterium smegmatis in Mice

“…The disruption of mce4 results in failure of M. tuberculosis to maintain chronic infection in mice, while retaining full virulence during the acute phase ( Mohn et al, 2008 ; Pandey and Sassetti, 2008 ). In contrast to these findings, the MCE family protein and the Mce-associated protein are generally considered as virulence factors, and are associated with lipid transport and host cell invasion ( Rodriguez et al, 2015 ; Perkowski et al, 2016 ). Ag85B may also contribute to the adherence, invasion, and dissemination of organisms in the host tissue, which can bind to Fn and play a critical role in mycobacterial adherence to the host cells ( Kassa et al, 2012 ).…”

Cell‐Peptide Specific Interaction Can Inhibit Mycobacterium tuberculosis H37Rv Infection

“…Receptor‐ligand binding assays were used for identifying Rv3705c peptides having high specific binding ability; this involved labelling each peptide with Na 125 I according to the techniques described by Yamamura [Yamamura et al, ], as reported in previous studies [Ocampo et al, , ,; Rodriguez et al, ]. Then 1.5 × 10 6 cells were placed per well in 96‐well dishes, in triplicate, for evaluating specific binding to the U937 and A549 cell lines and incubated at 4 °C (U937) and 37 °C (A549) for 2 h with increasing concentrations of radiolabeled peptide (0–950 nM) in the presence (inhibited binding) and absence (total binding) of the same non‐radiolabeled peptide at 40 μM concentration.…”

Mammalian cell entry operons; novel and major subset candidates for diagnostics with special reference to Mycobacterium avium subspecies paratuberculosis infection

“…2013; Rodriguez et al. 2015). The mce genes are also present in other species like Nocardia , Janibacter , Nocardiodes , Amycolatopsis and Streptomyces (Table 1) as well as in Gram-negative bacteria and have also been found encoded in plant genomes.…”

“…2005; Rodriguez et al. 2015). As the mce genes are absent in the human genome, these genes might also be represented as ideal candidates for drug targets (Zhang and Xie 2011).…”