Giardia lamblia: identification of molecules that contribute to direct mast cell activation

Abstract

Mast cells play a central role in the early clearance of the intestinal parasite Giardia lamblia. In a previous study, we reported that G. lamblia live trophozoites or trophozoite-derived total soluble extract induced direct activation (IgE-independent) of mast cells and release of IL-6 and TNF-α. To identify the Giardia molecules and the mast cell receptors involved in this activation, trophozoite-derived total soluble proteins separated into three fractions (F1-F3) were evaluated for its ability to activate mast cells in vitro. F2 activated mast cells in a greater extent than F1 and F3. Furthermore, F2 induced the release of IL-6 and TNF-α by mast cells. TLR2 and TLR4 expression increased slightly after mast cell stimulation with either F2 or total soluble extract; however, these receptors were not involved in F2 or total soluble extract-induced proinflammatory cytokine production. Proteins present in F2 as unique and high-intensity bands identified by liquid chromatography coupled with tandem mass spectrometry, include molecules with important biological activities such as enolase and arginine deiminase (ADI). Recombinant ADI and enolase were tested for their ability to activate mast cells, but only ADI induced a significant release of IL-6 and TNF-α. ADI product, citrulline but not ammonium, also induced mast cell release of TNF-α. Interestingly, recombinant ADI still stimulated the secretion of TNF-α by mast cells in a arginine-free medium, although in a lower extend that in the presence of arginine, indicating that either ADI itself can stimulate mast cells or through its metabolic product, citrulline.

The Chymase Mouse Mast Cell Protease-4 Regulates Intestinal Cytokine Expression in Mature Adult Mice Infected with Giardia intestinalis

“…There was also an effect on the adaptive immune system since mast cell-deficient mice failed to produce parasite-specific IgA [26]. Soluble Giardia trophozoite proteins can activate mast cells, and the secreted protein arginine deaminase (ADI) induces release of IL-6 and TNF-α [28], two cytokines that are important for clearance of G. intestinalis in mice [29][30][31].The mouse mast cell-specific chymase, mouse mast cell protease (mMCP)-4, which is released by activated connective tissue mast cells, may degrade IL-6 and TNF-α to inhibit excessive inflammation [32,33]. mMCP-4 can regulate the intestinal barrier function by affecting tight junctions and smooth muscle cells lining the intestine [34].…”

“…There was also an effect on the adaptive immune system since mast cell-deficient mice failed to produce parasite-specific IgA [26]. Soluble Giardia trophozoite proteins can activate mast cells, and the secreted protein arginine deaminase (ADI) induces release of IL-6 and TNF-α [28], two cytokines that are important for clearance of G. intestinalis in mice [29][30][31].…”

Fruit Morphology, Citrulline, and Arginine Levels in Diverse Watermelon (Citrullus lanatus) Germplasm Collections

“…The Citrulline Assay Kit (CAK) is a simple colorimetric assay that measures the amount of total citrulline present in biological samples such as cells, tissue, plasma serum, or urine samples [ 36 , 37 , 38 ]. Watermelon tissue sample extracts were treated with sodium dodecyl sulfate (SDS) and proteinase K to release free citrulline residues, followed by the addition of assay reagents (assay reagents A and B).…”

Conjugated linoleic acid enhances intestinal mucosal innate immunity against parasite Giardia lamblia in a murine model

“…La producción de algunas citocinas como TNF-α e IL-6, se ha descrito son necesarias para el control de Giardia en ratón (Zhou et al, 2003). Una fuente importante de estas citocinas proviene de los mastocitos los cuales pueden ser activados por metabolitos de Giardia (Muñoz-Cruz et al, 2018). Kamda et al (2012), demostró que la IL-6 producida por células dendríticas es muy importante para la respuesta al parásito.…”