The Brain Protein That May Be Both Good And Bad

A protein that is toxic and dangerous to the heart and nerves, a bad thing, may prevent formation of toxic protein clumps believed to contribute to Alzheimer’s disease, a good thing. This according to a new study led by a UT Southwestern researcher shows. The findings, published recently in the Journal of Biological Chemistry, may point to new treatments for Alzheimer’s disease, which for the time being has no cure or even effective treatment.

Researchers have long known that sticky plaques of a protein known as amyloid beta are a hallmark of Alzheimer's and are toxic to brain cells. However another protein, transthyretin (TTR), seemes to play a protective role, explains Lorena Saelices, Ph.D., assistant professor of biophysics and in the Center for Alzheimer's and Neurodegenerative Diseases at UTSW. In healthy people and animals, Dr. Saelices says, TTR helps transport thyroid hormone and the vitamin A derivative retinol to where they're needed in the body. In one study when mice modeled to have Alzheimer's disease were genetically altered to make more TTR, they were slower to develop an Alzheimer's-like condition; similarly, when they made less TTR, they developed the condition faster.

Do TTR's Both Prevent And Cause Amyloid-Related Diseases?

Saelices wondered whether there might be a connection between TTR's separate roles in both preventing and causing amyloid-related diseases. "It seemed like such a coincidence that TTR had such opposing functions," she says. "How could it be both protective and damaging?"

Saelices and her colleagues are currently testing whether this modified TTR peptide can prevent or slow progression of Alzheimer's in mouse models. If they're successful, she says, this protein snippet could form the basis of a new treatment for this recalcitrant condition.

"By solving the mystery of TTR's dual roles," she says, "we may be able to offer hope to patients with Alzheimer's."

What Is Amyloid Beta?

Amyloid Beta (beta-amyloid) is a peptide of 39–43 amino acids that appear to be the main constituent of amyloid plaques in the brains of Alzheimer's disease patients.

Source: Amyloid Beta - Merriam-Webster