04/02/2016 | BIOLOGICAL AND HEALTH SCIENCES
Close to understanding Parkinson’s disease
CONICET scientist participated in the studies that show for the first time how a key protein behaves in the development of the disease in live cells.
Andrés Binolfi at the IIDEFA- Photo: courtesy researcher.

Parkinson’s disease is a neurological disorder characterized by the presence of protein deposits mainly made up of α-synuclein (α-Syn) located in the inner part of neurons in the region of the brain called substantia nigra. These deposits, known as Lewy bodies or amyloid plaques, are abnormal accumulations that do not degrade and eventually eliminate the dopaminergic neurons, the ones in charge of producing the neurotransmitter dopamine.

For this reason, to understand how and why these plaques are formed plays a vital role in the development of an effective therapy against resulting disorders; thus enabling the attack to the nucleus of the disease itself (see box). Andres Binolfi, CONICET associate researcher at the Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario (IIDEFAR, CONICET-UNR) [Institute for Drugs Discovery of Rosario] since 2015, and a group of colleagues managed to determine the structural and functional behaviour of α-synuclein, a main component of those above mentioned deposits. The study was published in Nature and Nature Commmunications on January 26.

“Knowing the behaviour of a physiological environment is a great advance and in the future; it will be possible to apply it in the design of the drugs that combat the disease”, Binolfi states. He is one of the first authors and member of the Laboratorio Max Planck de Biología Estructural, Química y Biofísica Molecular de Rosario (MPLbioR) [Max Planck Laboratory for Structural, Chemical and Biophysics Biology of Rosario].

In order to study this aspect, the researchers used the in-cell NMR technique that allowed them to obtain accurate information about the behaviour of the molecules in live cells. “There is no other atomic resolution method capable of providing that type of information in live cells. The physical principles of other methodologies simply do not permit it”, Philipp Selenko explains. He is a researcher at the In-cell NMR Laboratory of the Leibniz-Institute for Molecular Pharmacology in Berlin, one of the pioneers in the use of this technique and coordinator of the study.

This methodology allowed the scientists to describe the proteins in physiological conditions in order to know which is the native structure and to know what situations make them aggregate, get together and begin the formation of plaques observed in Parkinson’s diseased brains. “This is the first time this type of study is conducted in the natural environment where the protein exists, in the cytoplasm of a neuronal cell. We noticed that behaves similar to what is known as a monomer and appears in a displayed way” Binolfi explains.

In the development of Parkinson’s disease, there is one factor that is hypothetically considered as a participant in the pathology: oxidative damage the α-Syn suffers from. As regards this, there is a study undertaken by Binolfi –he is the first author – and that was published in Nature Communications. The scientist discovered that inside the cell and in physiological conditions, the oxidative damage is combated by a system of the cell itself, but that would only work partially in the case of α-Syn.

“We noticed that the cell has specific machinery that repairs the damage but that in two places of one extreme of the protein – called C-terminal – is not effective and that produces the accumulation of modified species that altered cell function”, Binolfi explains.
“With these results we support more the hypothesis that suggests that oxidative stress would play a role in Parkinson’s disease development, so we described a mechanism through which the damage would accumulate in that protein”, the researcher concludes.

Not only for Parkinson

The same in-cell methodology could be used to study the behaviour of other proteins that, in a similar way as it is observed in Parkinson, are aggregated to produce other neurodegenerative diseases by plaque formation. “One example is β -amyloid peptide, which is also aggregated to form amyloid plaques in Alzheimer’s disease, out of the cell in this case; or Tau protein which forms it inside the cell”, the scientist states.

Selenko, for his part, affirms that “neurodegenerative disorders that involve pathological structural re-arrangements of protein architectures could be studied with a tool to directly look at the structures of these proteins under healthy and sick cell conditions, and this is exactly what in-cell NMR and EPR (and only they) can do.

Parkinson’s disease

Parkinson’s disease is the second most frequent neurodegenerative disease after Alzheimer’s disease. According to the information published in the National Health Organization in 2004, 5.2 millions of people in the world suffer from this disease and 1.2 millions of that people live in the American continent.
Age is closely linked to the disease and the average age is 60, although there have been cases of the disease in twenty-year-old or younger patients.

Clinically, this disease is characterized by trembling, stiffness, slow movements (bradykinesia) and speed’s deterioration. At cellular level, one distinctive feature of Parkinson’s disease is the degeneration of dopaminergic neurons – because they produce the neurotransmitter called dopamine – in the substantia nigra, linked to the presence of protein aggregates – clusters – called Lewy Bodies.

It is actually the lack of dopamine production and, to a lesser extent, of other neurotransmitters the responsible for the clinical symptoms of the patients. This is the result of the degeneration and death of the dopaminergic neurons of the substantia nigra, associated to the presence of protein aggregates.

By María Bocconi

About the study:

“Structural disorder of monomeric alfasynuclein persist in mammalian cells”
Francois-Xavier Theillet. In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
Andres Binolfi, associate researcher, IIDEFAR-CONICET.MPLbioR-UNR and In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
BeataBekei. In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
Andrea Martorana.Department of Chemical Physics, Wizmann Institute of Science, Israel.
Honor May Rose: In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
MarchelStuiver. In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
Silvia Verzini: In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute Molecular Pharmacology. Berlín, Alemania.
Dorothea Lorenz: Department of Molecular Physiology and Cell Biology, Leibniz institute for Molecular Pharmacology.
Marleen van Rossum: In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.
DaniellaGolbfarb: Departmento of Chemical Physics, Waizmann Institute of Science, Israel.
Phillipp Selenko: In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Molecular Pharmacology. Berlin, Germany.

“Intracellular repair of oxidation-damaged a-synuclein fails to target C-terminal modification sites”
AndresBinolfi, , Investigador Adjunto, IIDEFAR-CONICET. MPLbioR-UNR and In-cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute for Moecular Pharmacology.Berlin, Germany.
Antonio Limatola, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology and Department of Pharmacy, University of Naples ‘Federico II’, Via DomenicoMontesanto, Napoles, Italy.
Silvia Verzini, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
Jonas Kosten, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
Francois-Xavier Theillet, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
Honor May Rose, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
BeataBekei, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
MarchelStuiver, Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
Marleen van Rossum Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute for Molecular Pharmacology, Berlin, Germany.
Philipp Selenko Department of NMR-supported Structural Biology, In-Cell NMR Laboratory, Leibniz Institute of Molecular Pharmacology, Berlin, Alemania.