In 1998, when Timothy Hla, PhD, and his colleagues identified and cloned the receptor for sphingosine-1-phosphate (S1P), it generated a lot of excitement. S1P, a lipid originally discovered in the 1960s, was known to play various roles in the body and in disease. But it wasn’t thought that lipids could have receptors, and it wasn’t fully appreciated that they could send messages into cells.
“We were very busy for the next 10 years,” says Hla. “S1P biology has become quite a large field.”
Hla heads a lab in Boston Children’s Hospital’s Vascular Biology Program, so among the group’s questions was what S1P does in the vascular system. In the early 2000s, Hla and colleagues showed that S1P is essential for angiogenesis, or the growth of blood vessels, finding that endothelial cells, which line blood vessels, are rich in the S1P receptor. When they blocked the S1P pathway in animal models, embryos could not form blood vessels and died.
