Melamine: An Emerging Neurotoxicant?

Abstract

Melamine is an organic compound used in combination with formaldehyde in the manufacture of plastics and also used as a flame retardant especially in buses and aircrafts. In the summer of 2008, multiple illness and deaths of children in China was associated with melaminetainted powdered infant milk. Ever since, there has been serious public health concern over the toxic potentials of melamine especially amongst growing infants. We therefore set to investigate the neurotoxicity of melamine using transient transfection-based reporter gene assay and found that low dose melamine suppressed thyroid hormone receptor (TR)-mediated gene expression at 1uM. We further examined the effect of melamine on TR-thyroid hormone response (TRE) binding and found no dissociation of TR from TRE. Melamine did not also suppress co-activator (Steroid receptor co-activator 1; SRC-1) binding with TR, neither did it recruit co-repressors (nuclear co-repressor; N-CoR) to TR in the presence of thyroid hormone. Taken together, our data shows that melamine can interfere with TR-mediated gene expression and consequently may be inimical to the developing brain.