Neurodegeneration refers to the progressive loss of structure and function of nerve cells, also called neurons. The human brain is composed of billions of neurons that form an effective communicative network. When neurons get damaged and die, however, they cannot simply be replaced like a malfunctioning part of a machine. Therefore, as more and more neurons die, this will eventually result in a negative impact on brain function. When we get older the risk for neurodegeneration increases and we may develop the symptoms of neurodegenerative diseases.
There is a great number of neurodegenerative diseases. Some types mainly entail cognitive impairment (i.e. dementia) such as loss of memory, disorientation and difficulties to manage the routines of everyday life. Alzheimer’s disease is the most prevalent cause of dementia making up approximately two third of all cases worldwide. Progressively strong tremor is the main symptom of Parkinson’s disease which is one of the neurodegenerative diseases mainly resulting in motor impairment. Further examples of neurodegenerative diseases are Huntington’s and Amyotrophic Lateral Sclerosis (ALS). The latter has become known through Stephen Hawkins, a famous astrophysicist, who lives with ALS since 1963.
Dementia does not only constitute a tremendous burden for the patients and their families, but it also has considerable social and economic effects. Medication for dementia, professional care and informal care by relatives cause a substantial financial drain for the health care system. According to the World Alzheimer Report 2014, the global cost of dementia was estimated to be US$ 604 billion in 2010, with the great majority of the costs incurring in industrial nations.
Although the symptoms of neurodegenerative diseases vary, many of them have one observable feature in common: the accumulation of protein clumps (aggregates) inside or outside of nerve cells. What is yet unclear, however, is whether these protein aggregates themselves cause neurodegeneration or whether other processes linked to the protein aggregates are toxic for the neurons. Therefore, understanding how these protein aggregates form and revealing the mechanisms leading to the death of neurons is vital for developing novel therapeutic strategies to fight some of the most debilitating diseases of our time.