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Alassane-Kpembi, I.

Publications and source records attributed to Alassane-Kpembi, I..

2 recordsLinked to original sources

Low doses of the food contaminant Deoxynivalenol trigger apoptosis and alter GnRH stimulation of gonadotroph cells

The Fusarium mycotoxin deoxynivalenol (DON) is one of the most frequently occurring food contaminants. Nearly all individuals are exposed to DON, due to it widespread presence in grains and grain-based products. Chronic DON poisoning is associated with growth retardation, immunotoxicity as well as impaired reproduction and fetal development. At the molecular level, DON alters intracellular signaling by activating mitogen-activated protein kinases (MAPKs) that modulate cell growth, differentiation, and apoptosis. Of note, these MAPKs are also critical mediators of gonadotrophin-releasing hormone (GnRH)-induced synthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by pituitary gonadotrope cells. So far, no research has explored the potential endocrine-disrupting effects of DON on pituitary gonadotropins production. Herein, we show the first evidence that DON affects LH production by the immortalized gonadotrope-like cell line L{beta}T2 in a concentration-dependent manner. Taken together, our experiments demonstrated that low concentrations of DON affect GnRH-induced signaling through a mechanism that, at least in part, involves apoptosis and inhibition of GnRH-induced phosphorylation of ERK-MAPK. Consequently, DON also affects the GnRH-induced expression of Cga and Lhb, two critical genes for LH synthesis and secretion by gonadotrope cells in mammals. This research broadens our knowledge of the toxicity of DON and brings a new depth to the potential neuroendocrine implications for reproduction. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/607800v2_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@78d077org.highwire.dtl.DTLVardef@1be5bdaorg.highwire.dtl.DTLVardef@804d49org.highwire.dtl.DTLVardef@1520136_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

Phosphorylation of Zearalenone retains its toxicity

Microbial biotransformation of Zearalenone (ZEN) is a promising deactivation approach. The residual toxicity and stability of Zearalenone-14-phosphate (ZEN-14-P) and Zearalenone-16-phosphate (ZEN-16-P), two novel microbial phosphorylation products of ZEN, remain unknown. We investigated the cytotoxicity, oxidative stress, pro-inflammatory, and estrogenic activity of phosphorylated ZENs using porcine intestinal cells and uterine explants, and human endometrial cells, and traced their metabolic fate by LC-MS/MS analysis. The phosphorylated ZENs significantly decreased the viability of IPEC-J2 and Ishikawa cells. Similar to ZEN, phosphorylation products induced significant oxidative stress, activated the expression of pro-inflammatory cytokines, and demonstrated estrogenic activity through upregulation of estrogen-responsive genes, activation of alkaline phosphatase and proliferation of endometrial glands. LC-MS/MS analysis pointed that although phosphorylated ZENs are partially hydrolyzed to ZEN, their respective metabolic pathways differ. We conclude that phosphorylation might not be sufficient to detoxify ZEN, leaving its cytotoxic, pro-inflammatory and estrogenic properties intact. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=60 SRC="FIGDIR/small/605906v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@94e741org.highwire.dtl.DTLVardef@1da9d53org.highwire.dtl.DTLVardef@18ee655org.highwire.dtl.DTLVardef@b4035b_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗