People whose genome carries certain variations have a particularly high risk of developing Parkinson's disease.
In particular, genetic variants in a gene referred to as GBA1 (glucocerebrosidase) are associated to an increased risk for Parkinson’s. Researchers of the German Center for Neurodegenerative Diseases (DZNE) and the Hertie Institute for Clinical Brain Research have now pinpointed the consequences that genetic variations in GBA1 have on neurons – consequences that had been largely undetermined to date.
Using stem cells, they found that mutations affecting GBA1 impair calcium metabolism and the cell’s “garbage disposal” that normally digests and recycles defective substances including alpha-synuclein, the protein that accumulates in the brain of patients suffering from Parkinson’s. This research shows a link between alterations in the GBA1 gene and cellular dysfunctions in Parkinson’s disease for the first time. It also suggests potential targets for drugs and biomarkers that could be useful for diagnosis. The study is published in the journal Nature Communications.
In people suffering from Parkinson’s, brain cells that are supposed to produce a neurotransmitter called dopamine, die off over time, making it difficult for these patients to control their movements. They may also suffer from insomnia and depression. And as the illness progresses, they may also develop dementia. To date, there is no cure for Parkinson’s disease and the actual triggers of the death of neurons, i.e. of the so-called neurodegeneration, are still unknown. However, mutations of a certain gene referred to as GBA1, have been identified as a major risk factor. “This gene contains the blueprint of an enzyme, called glucocerebrosidase, that is involved in the processing of certain lipids,” explains DZNE researcher Michela Deleidi, who also works at the Hertie Institute for Clinical Brain Research. “Alterations in this gene do not necessarily lead to Parkinson’s. In fact, whereas people with mutations in both copies of the gene are affected by a metabolic disorder called Gaucher’s disease, both Gaucher’s disease patients and individuals with a mutation in just one copy of the gene are predisposed to develop Parkinson’s.”
Up to now, the consequences these mutations have on nerve cells were largely unexplored. “Studies addressing the effect of these mutations in Parkinson’s disease have not been performed yet,” observes Deleidi. She therefore set out to elucidate the consequences of the genetic mutations. The study involved a team based in Tübingen including Professor Thomas Gasser, as well researchers in Italy and the United States.
Induced stem cells
Human nerve cells are not readily accessible and it is very difficult to cultivate such cells in the laboratory if they are obtained, for instance, through a surgical procedure. Hence, Deleidi and her colleagues chose a different approach: they took skin cells from Parkinson’s and Gaucher’s patients harbouring mutations of the GBA1 gene and converted them into “induced pluripotent stem cells” by manipulating their genetic programme. Stem cells are unspecialized cells that have the potential to evolve into virtually any type of cell in the body. “We differentiated stem cells into dopamine-producing neurons,” the scientist explains. These cells contained the patients’ DNA and therefore also the GBA1 gene mutations. “Next, we investigated the effects that these mutations had on the cell. We looked at those effects which make the cell susceptible to neurodegeneration.” Other neurons that also originated from patients, served as controls. However, in these cells the GBA1 mutations had been corrected by genetic engineering.
Conclusions: While the cells carrying corrected DNA did not show irregularities, the researchers found various dysfunctions in the mutated neurons. The effects were similar in cells obtained from individuals suffering from Parkinson’s and in cells from Gaucher’s patients. First, the activity of glucocerebrosidase was reduced, in addition the overall cells’ ability to process and dispose of certain metabolites was impaired. “The activity of the corresponding enzymes was lower than normal. This means that certain substances accumulate and damage the neurons,” the researcher explains.
These results were consistent with other findings based on patient studies. Enzymes showing unusual behavior in the cell cultures also revealed reduced activity in the spinal fluid of patients. This comprised not only glucocerebrosidase. The activity of other enzymes involved in the metabolism of lipids was also reduced. “Measurement of the enzyme activity may provide important clues to disease. These enzymes may serve as biomarkers, in other words as indicators that could be helpful for the diagnosis of Parkinson's disease,” Deleidi points out.
The researchers also found increased concentrations of the protein alpha-synuclein in the nerve cells they studied in laboratory. This protein does play a key role in Parkinson’s disease because it aggregates into microscopically small lumps, which are suspected to damage nerve cells.
Potential approaches to treatment
In addition, the calcium metabolism was impaired in neurons with mutated DNA. Whenever calcium levels rise, this has a signaling effect that triggers various cellular processes. “We found that the mutant neurons could not properly regulate the concentration of calcium ions and this makes them more vulnerable to cellular stress. They are therefore more sensitive to disturbances,” Deleidi observes. “Importantly, calcium metabolism may be a target for novel therapeutic interventions. In summary, our study clearly shows that there is a direct link between mutations in the GBA1 gene and cellular dysfunctions. Thus, you may start early in the chain of events and try to enhance the activity of the enzyme glucocerebrosidase to prevent or delay the disease.”
“iPSC-derived neurons from GBA1-associated Parkinson’s disease patients show autophagic defects and impaired calcium homeostasis”, David C. Schöndorf, Massimo Aureli, Fiona E. McAllister, Christopher J. Hindley, Florian Mayer, Benjamin Schmid, S. Pablo Sardi, Manuela Valsecchi, Susanna Hoffmann, Lukas Kristoffer Schwarz, Ulrike Hedrich, Daniela Berg, Lamya S. Shihabuddin, Jing Hu, Jan Pruszak, Steven P. Gygi, Sandro Sonnino, Thomas Gasser, Michela Deleidi, Nature Communications, 2014, http://dx.doi.org/10.1038/ncomms5028
Dr. Marcus Neitzert | idw - Informationsdienst Wissenschaft
Cells migrate collectively by intermittent bursts of activity
30.09.2016 | Aalto University
The structure of the BinAB toxin revealed: one small step for Man, a major problem for mosquitoes!
30.09.2016 | CNRS (Délégation Paris Michel-Ange)
Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.
Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...
Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.
Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
30.09.2016 | Event News
29.09.2016 | Event News
28.09.2016 | Event News
30.09.2016 | Materials Sciences
30.09.2016 | Earth Sciences
30.09.2016 | Life Sciences