Recombinant Fasciola hepatica fatty acid binding protein suppresses toll-like receptor stimulation in response to multiple bacterial ligands

Abstract

Recently, we reported that a native Fasciola hepatica fatty acid binding protein (FABP) termed Fh12 is a powerful anti-inflammatory protein capable of suppressing the LPS-induced expression of inflammatory markers in vivo and in vitro. Because the purification of a protein in native form is, in many situations not cost-beneficial and unsuitable for industrial grade scale-up, this study accomplished the task of optimizing the expression and purification of a recombinant form of FABP (Fh15). Additionally, we ascertained whether this molecule could exhibit a similar suppressive effect on TLR-stimulation and inflammatory cytokine expression from macrophages than those previously demonstrated for the native molecule. Results demonstrated that Fh15 suppresses the expression of IL-1β and TNFα in murine macrophages and THP1 Blue CD14 cells. Additionally, Fh15 suppress the LPS-induced TLR4 stimulation. This effect was not impaired by a thermal denaturing process or blocked by the presence of anti-Fh12 antibodies. Fh15 also suppressed the stimulation of various TLRs in response to whole bacteria extracts, suggesting that Fh15 could have a broad spectrum of action. These results support the possibility of using Fh15 as an excellent alternative for an anti-inflammatory drug in preclinical studies in the near future.

Extracellular Vesicles From the Helminth Fasciola hepatica Prevent DSS-Induced Acute Ulcerative Colitis in a T-Lymphocyte Independent Mode

“…The accurate identification of the molecules responsible for the anti-inflammatory effect is underway, but suitable candidates are molecules previously identified in FhEVs, like FABPs ( Cwiklinski et al, 2015 ), which have been shown to induce anti-inflammatory response in animal models by diminishing the levels of TNFα ( Ramos-Benitez et al, 2017 ). Other exosome-contained molecules like miRNAs represent potential candidates as they may act as immunomodulators of the intestinal innate immune response ( Buck et al, 2014 ).…”

Modulation of Host Immunity by Helminths: The Expanding Repertoire of Parasite Effector Molecules

“…A different mechanism is deployed by the immunomodulatory ES protein Fh12 (and its recombinant form, Fh15) from the liver fluke Fasciola hepatica . The Fh12 and Fh15 proteins induce alternative activation in human monocyte-derived macrophages (Mo-Macs), suppress macrophage activation by TLR2, TLR4, TLR5, and TLR8 ligands, and inhibit inflammatory cytokine production in septic shock ( Ramos-Benítez et al., 2017 ). They bind to the TLR4 cofactor CD14 and reduce its expression, mediating suppression of TLR4 responses.…”

Fasciola hepatica-Derived Molecules as Regulators of the Host Immune Response

“…Investigations into their anti-inflammatory properties demonstrated that the 12 kDa Fh12 product reduced pro-inflammatory cytokine production in the LPS-induced model of murine sepsis ( 45 ). Similarly, the 14.5 kDa Fh15 molecule attenuated production of IL-1β and TNF-α in human THP-1 macrophages ( 46 ). In a murine model of sepsis, Fh15 treatment was associated with a significant decrease in circulating cytokines ( 46 ).…”

“…Similarly, the 14.5 kDa Fh15 molecule attenuated production of IL-1β and TNF-α in human THP-1 macrophages ( 46 ). In a murine model of sepsis, Fh15 treatment was associated with a significant decrease in circulating cytokines ( 46 ).…”