Environmentally Relevant Level of Aflatoxin B₁ Dysregulates Human Dendritic Cells Through Signaling on Key Toll-Like Receptors

Abstract

Aflatoxins (AFs) are highly hazardous fungal biometabolites usually present in feeds and foods. Aflatoxin B (AFB) is the most toxic and a known carcinogen. Toll-like receptors (TLRs), highly expressed by myeloid dendritic cells (DC), are key innate immune-surveillance molecules. Toll-like receptors not only sense pathogen-associated molecular patterns but also contribute to infections and cancer. To assess AFB-TLR interactions on human myeloid DC, pure CD11c DC were generated from monocytes isolated from healthy individuals and then exposed to relevant level of AFB for 2 hours. Both quantitative polymerase chain reaction and flow cytometric assays were used to quantify, respectively, expression of TLR2 and TLR4 at the messenger RNA (mRNA) and protein levels in these DC. Levels of interleukin (IL) 1β, IL-6, and IL-10 were also analyzed in AFB- and mock-treated DC. Compared to nontreated CD11c DC, expression levels of both TLR2 and TLR4 mRNA and proteins were significantly upregulated in AFB-treated cells. Further, although IL-10 levels in AFB-treated DC were similar to those in the mock-treated DC, the AFB-exposed DC secreted higher amounts of IL-1β and IL-6. Dendritic cells are sensitive to environmentally relevant level of AFB, and TLR2 and TLR4 are involved in sensing AFB Considering the broad roles of TLR2, TLR4, and DC in immunity and infections, our novel findings open a new door to understanding the molecular mechanisms and functional consequences of AFB in inducing immunodysregulation, immunotoxicity, and thus (non)infectious diseases in humans.

Seasonally Feed-Related Aflatoxins B1 and M1 Spread in Semiarid Industrial Dairy Herd and Its Deteriorating Impacts on Food and Immunity

“…The background of the selected doses examined here was (1) in line with the first part of this study on AFB 1 and AFM 1 quantification, (2) our current understanding on the metabolism and toxicodynamics of AFB 1 , and (3) from researchers [2][3][4][5]20] in bovine, porcine, and human in vitro models. Researchers have even used higher doses of AFs [21].…”

“…Aflatoxins (AFs) are highly carcinogenic and immunotoxic secondary metabolites produced mainly by Aspergillus (A) flavus and A. parasiticus in feed/foods [1][2][3][4]. Environmentally, AFs exposure is inevitably rising [1,5,6], and their seasonal spread and impacts in semiarid industrial dairy farms' mi(a)croenvironment remain unaddressed.…”

Stressed (acute) mice display neuroimmunodysregulation and defective innate immune response against coliform infection

“…Splenic immune cells and brain (sagittal sections of frontal part of whole brain) were separated accordingly [10,16]. The harvested RBC-free splenic cell suspensions were then washed (400 × g, 10 min, 4°C) twice with RPMI-1640, counted (in nigrosin solution) in a Neubauer chamber, and after cell viability assessment using nigrosin solution and the Neubauer chamber, in which necrotic cells appeared bright and dark-blue in the mixture [10][11][12][13][14][15][16], respectively, the cells and brain were eventually used for further cellular and molecular analyses.…”

“…To assess the effect of ARS on the functional activity of splenic phagocytes, MDMSC of post-stress hour (psh) 12 were isolated by plastic adherence, after incubation of splenic immune cells for 2 h in a 95% humidity with 5% CO 2 at 37°C, as previously described in porcine [10,16] and human [13]. In brief, 2 × 10 5 MDMSC were treated with 2 × 10 6 FITC-loaded polystyrene microparticles (1.0 μm, Sigma-Aldrich; St. Louis, MO) at 10 beads/MDMSC and incubated for 3 h (37°C, 5% CO 2 and 95% humidity).…”

“…TLR are also involved in many neurodegenerative diseases [3,[6][7][8]. TLR have also been increasingly used as novel immunemolecules to extrapolate dysregulatory/toxicity of hazard materials [9][10][11][12][13]. Studies on the effects of acute restraint stress (ARS) on TLR are rare.…”