The TvLEGU-1, a Legumain-Like Cysteine Proteinase, Plays a Key Role inTrichomonas vaginalisCytoadherence

Abstract

The goal of this paper was to characterize a Trichomonas vaginalis cysteine proteinase (CP) legumain-1 (TvLEGU-1) and determine its potential role as a virulence factor during T. vaginalis infection. A 30-kDa band, which migrates in three protein spots (pI~6.3, ~6.5, and ~6.7) with a different type and level of phosphorylation, was identified as TvLEGU-1 by one- and two-dimensional Western blot (WB) assays, using a protease-rich trichomonad extract and polyclonal antibodies produced against the recombinant TvLEGU-1 (anti-TvLEGU-1r). Its identification was confirmed by mass spectrometry. Immunofluorescence, cell binding, and WB assays showed that TvLEGU-1 is upregulated by iron at the protein level, localized on the trichomonad surface and in lysosomes and Golgi complex, bound to the surface of HeLa cells, and was found in vaginal secretions. Additionally, the IgG and Fab fractions of the anti-TvLEGU-1r antibody inhibited trichomonal cytoadherence up to 45%. Moreover, the Aza-Peptidyl Michael Acceptor that inhibited legumain proteolytic activity in live parasites also reduced levels of trichomonal cytoadherence up to 80%. In conclusion, our data show that the proteolytic activity of TvLEGU-1 is necessary for trichomonal adherence. Thus, TvLEGU-1 is a novel virulence factor upregulated by iron. This is the first report that a legumain-like CP plays a role in a pathogen cytoadherence.

Identification of 24h Ixodes scapularis immunogenic tick saliva proteins

“…The primary cleavage of hemoglobin in I. ricinus midgut occurs with the assistance of legumain (Horn et al, 2009). Legumain-like proteases appear to be common among other parasites such as Schistosoma mansoni and Trichomonas vaginalis , which is understandable due to their shared goal of modulating their host’s immune system while acquiring nutrients (Dalton et al, 1997; Rendón-Gandarilla et al, 2013). …”

Humoral and T cell–mediated immune response against trichomoniasis

“…TvLEGU‐1 is a novel virulence factor that is localized in lysosomes, Golgi complex and surface of T. vaginalis . The presence of TvLEGU‐1 in the Golgi complex indicates that this CP undergoes a part of its processing and maturation step in this organelle .…”

“…TvLEGU‐1 is also placed on the surface of the parasite, and its expression is upregulated by iron. It binds with high affinity to the surface of HeLa cells, playing an important role in parasite cytoadherence . Additionally, the reduction in T. vaginalis cytoadherence by specific legumain inhibitor suggests that the TvLEGU‐1 proteolytic activity may play an important role in the host‐parasite interaction during trichomonal attachment.…”

“…Additionally, the reduction in T. vaginalis cytoadherence by specific legumain inhibitor suggests that the TvLEGU‐1 proteolytic activity may play an important role in the host‐parasite interaction during trichomonal attachment. The Aza‐Peptidyl Michael Acceptor that acts as an inhibitor of legumain‐1 proteolytic activity decreased trichomonal cytoadherence up to 80% . TvLEGU‐1 is also found in vaginal secretions of T. vaginalis ‐infected patients .…”

Mechanisms of Tritrichomonas foetus Pathogenicity in Cats with Insights from Venereal Trichomonosis

“…At least 23 and 15 different cysteine proteases have been identified in T. vaginalis and bovine T. foetus , respectively 60, 67, 68, 69, 70. At least three T. vaginalis surface‐expressed cysteine proteases (CP30, CP65 and TvLEGU‐1) play a key role in adhesion and adhesion‐dependent cytotoxicity to cervical and vaginal epithelial cells 48, 66, 71, 72, 73, 74…”