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Tuesday, February 12, 2013

Misfolded proteins lead to heart disease

Proper protein folding is critical for cell functioning. Lately, there’s been news that protein misfolding may be implicated in a range of neurodegenerative diseases such as Parkinson’s, Huntington’s and Alzheimer’s. Monte Willis and Cam Patterson of the University of North Carolina, Chapel Hill, review the case that heart disease should be added to the list.

There’s no doubt that the cardiomyocytes (heart cells) that give the heart its contractile power live in a delicate balance of protein formation and destruction. In a healthy heart, proteins are constantly being turned over with new proteins being made and old or damaged proteins degraded and removed from the cell. Misfolded proteins can be particularly problematic.

One problem is that misfolded proteins can assemble into larger clumps that disrupt cell functions. And in fact, a variety of cardiac stress disorders are associated with these protein masses. You can induce mouse heart cells to accumulate aggregates of misfolded proteins by stressing them in varying ways and you can observe these accumulations in the damaged hearts of human patients.

These and other lines of evidence suggest that protein folding is critical for proper cardiac functioning. It also means that researchers would do well to focus on preventing protein misfolding as a way to combat heart disease. One way to do this might be to increase the number of protein chaperones (quality control proteins that ensure the proper folding and positioning of other proteins). Mice with a genetic predisposition to heart disease that had been given drugs to increase the expression of these chaperones had significantly less cardiac disease than their untreated fellows.

Willis MS, & Patterson C (2013). Proteotoxicity and cardiac dysfunction--Alzheimer's disease of the heart? The New England journal of medicine, 368 (5), 455-64 PMID: 23363499.