PhD, Rutgers University, 1978
Tight barriers such as those expressed by epithelial cells lining the intestine or kidney tubules, or by endothelial cells in the brain (blood brain barrier), restrict the transport of charged chemical or chemicals with high molecular weight. These chemicals may include ions and hormones or pollutants in the environment. The anatomical basis of the tight barrier is tight junctions that fuse the cells together thereby preventing chemicals from passing between cells. Because tight barriers would also slow the transport of needed nutrients, cells forming tight barriers express specific transporters. Our laboratory has been studying transporters and their interaction with environmental toxins. We found, for example, that a iron and zinc transporters mediate the uptake of toxic metals such as lead and cadmium. Additionally, trivalent metals such as aluminum and lanthanum activate iron transporters and also increase the transport of toxic metals. Further characterization of iron transporters and their involvement in lead poisoning is underway in our laboratory.