Diseases ranging from Alzheimer's to type II diabetes may arise from the same molecular mistake: a misfolding of proteins, which then gang up and wreak havoc in cells. Eliminating these aggregates, scientists say, could potentially halt or undo the damage inflicted by these diseases.

In a study published today in the journal Nature, Christopher Dobson of the University of Cambridge and colleagues report that even normally harmless proteins, when coaxed into misfolding and clumping together, kill cells in culture. The inherent toxicity of these aggregates, they say, puts paid to the idea that avoidence of such protein clumping "is crucial for the preservation of biological function." Furthermore, the investigators note, it suggests that degenerative conditions such as Alzheimer's and Creutzfeldt-Jacob disease--so-called protein deposition diseases--have this aggregation feature in common.

A second study detailed in the same issue, conducted by Harvard University researcher Dennis Selkoe and colleagues, found that small aggregates, or oligomers, of amyloid beta protein (which in Alzheimer's patients accumulates in large clumps) impaired synapse function when injected into rat brains. Reducing the levels of potentially dangerous amyloid beta oligomers may therefore represent an attractive approach to treating Alzheimer's, the authors conclude. To that end, they have already identified two chemical compounds that inhibit oligomer formation. But they add that antiaggregation compounds would have to also reduce monomer concentrations, so as to head off initial clumping.

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