Alzheimer's disease and dementia Protein deposits in the nerve cells are damaging

Researchers decipher harmful effects of protein aggregates on the nerve cells
Protein deposits are linked to neurodegenerative diseases such as Alzheimer's disease or Huntington's disease, but the exact mechanism of action of protein aggregates has remained unclear. Scientists at the Max Planck Institute of Biochemistry in Martinsried and the Ruhr University Bochum (RUB) have now found out in a recent study, how the protein clumps harm the nerve cells.

"Protein clumps, such as those that occur in Alzheimer's or Huntington's disease, are particularly harmful if they occur in the cytoplasm," says the RUB of the current study results. If the protein deposits in the cell nuclei, this would be much less dangerous for the nerve cells. Their results have been researched by Professor Dr. Ulrich Hartl and Dr. med. Mark Hipp from the Max Planck Institute of Biochemistry and Professor Konstanze Winklhofer and Prof. Dr. med. Jörg Tatzelt from the Institute for Biochemistry and Pathobiochemistry at the RUB published in the journal "Science".

Protein deposits can damage the nerve cells and lead to neurodegenerative diseases. (Image: Juan Gärtner / fotolia.com)

Protein aggregates in the cytoplasm especially harmful
The protein aggregates have been suspected for a long time as possible causes of nerve cell death in neurodegenerative diseases. However, it was unclear how they damage the cells. The new study led by Prof. dr. Hartl and dr. Hipp has now shown that especially protein aggregates in the cytoplasm damage the cells. The scientists studied in cell cultures, the effect of the protein huntingtin, which is responsible for Huntington's disease and clumped in nerve cells to aggregates. In the clumps, the researchers were able to detect, among other components of the cellular transport machinery, which consequently did not work properly, reports the RUB. The consequences for the cells are fatal. If the construction instructions for proteins, the RNA, can no longer be transferred from the cell nucleus to the cytoplasm via the usual transport route, the production of vital proteins is impaired there and the cell dies, according to the University.

Important transport routes disturbed
The scientists found in their investigations that the protein aggregates in the cytoplasm were more toxic to the nerve cells than aggregates in the cell nucleus. This is due to the fact that they interfere among other important transport routes in the cell. With their sticky properties, vital proteins would stick to them and the cell would die. Why the aggregates in the cell nucleus have no equally harmful effect remains unclear and must be investigated in further studies, the researchers report. (Fp)