10 research outputs found
Carbamate Insecticides Target Human Melatonin Receptors
Carbaryl (1-naphthyl methylcarbamate)
and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl
methylcarbamate) are among the most toxic insecticides, implicated
in a variety of diseases including diabetes and cancer among others.
Using an integrated pharmacoinformatics based screening approach,
we have identified these insecticides to be structural mimics of the
neurohormone melatonin and were able to bind to the putative melatonin
binding sites in MT<sub>1</sub> and MT<sub>2</sub> melatonin receptors <i>in silico</i>. Carbaryl and carbofuran then were tested for
competition with 2-[<sup>125</sup>I]-iodomelatonin (300 pM) binding
to hMT<sub>1</sub> or hMT<sub>2</sub> receptors stably expressed in
CHO cells. Carbaryl and carbofuran showed higher affinity for competition
with 2-[<sup>125</sup>I]-iodomelatonin binding to the hMT<sub>2</sub> compared to the hMT<sub>1</sub> melatonin receptor (33 and 35-fold
difference, respectively) as predicted by the molecular modeling.
In the presence of GTP (100 ÎĽM), which decouples the G-protein
linked receptors to modulate signaling, the apparent efficacy of carbaryl
and carbofuran for 2-[<sup>125</sup>I]-iodomelatonin binding for the
hMT<sub>1</sub> melatonin receptor was not affected but significantly
decreased for the hMT<sub>2</sub> melatonin receptor compatible with
receptor antagonist/inverse agonist and agonist efficacy, respectively.
Altogether, our data points to a potentially new mechanism through
which carbamate insecticides carbaryl and carbofuran could impact
human health by altering the homeostatic balance of key regulatory
processes by directly binding to melatonin receptors