Scientists have long known that living cells are master recyclers, constantly breaking down old parts and building them back up into new molecular machines.
Now, researchers have taken a closer look at the life cycle of energy-generating cellular power plants—called mitochondria— inside brain cells, and how they might be recycled. They showed that genes associated with Parkinson’s disease play key roles in this process.
“This work gives us unprecedented insight into mitochondria’s life cycle and how they are recycled by key proteins that, when mutated, cause Parkinson’s disease,” says Gladstone Associate Investigator Ken Nakamura, MD, PhD, senior author of the new study.
“It suggests that mitochondrial recycling is critical to maintaining healthy mitochondria, and disruptions to this process can contribute to neurodegeneration.”
In most cells, damaged mitochondria are decomposed in a process known as mitophagy, which is initiated by two proteins, PINK1 and Parkin.
Mutations in these same proteins also cause hereditary forms of Parkinson’s disease. While the role of PINK1 and Parkin in mitophagy has been heavily studied in many cell types, it has been unclear whether these proteins act the same way in neurons—the type of brain cells that die in Parkinson’s disease. Indeed, neurons have unusually high energy needs and their mitochondria are much more resistant to degradation by Parkin than those in other cell types.
In the new study published in the journal Science Advances, Nakamura’s group followed mitochondria inside living neurons and examined how PINK1 and Parkin affected their fate.
But mitochondria are small and they move inside cells, frequently fusing with each other or splitting in two, which makes them difficult to track.
“We had to develop a new way of tracking individual mitochondria over long periods of time, almost a full day,” says Zak Doric, a graduate student at Gladstone and UC San Francisco (UCSF) and co-first author of the new study. “Getting that technique up and running was quite a challenge.”
The scientists also used a method that allowed them to generate larger-than-normal mitochondria, making them easier to see under a microscope.
They found that Parkin proteins encircled damaged mitochondria and targeted them for degradation, demonstrating that mitophagy starts in neurons in the same way as in other cell types. But thanks to their new approach, they could watch the process unfold in great detail.
For instance, they documented the key initial steps in which damaged, Parkin-coated mitochondria fuse with other components inside the cell to form mitochondria-degrading structures called mitolysosomes.
“We were able to visualise these steps at a level that hasn’t been done before in any cell type,” says Nakamura, who is also an associate professor of neurology at UCSF.
The high resolution of their approach will allow them to understand with great precision how Parkin and PINK1 affect mitochondrial degradation in Parkinson’s disease.
A New Kind of Recycling
The researchers then examined the later phases of mitophagy, monitoring what happens to mitochondria in the mitolysosomes.
“Until now, nobody has known what happens next to these mitolysosomes,” says Nakamura.
So far, scientists had assumed that mitolysosomes rapidly break down into molecules that the cell can reuse to build new mitochondria from scratch. Nakamura and his team showed that, instead, the mitolysosomes survived for hours inside cells.
Unexpectedly, some mitolysosomes were engulfed by healthy mitochondria, while other times, they suddenly burst, releasing their contents into the interior of the cell, including some proteins that were still functional.
“This appears to be a new mitochondrial quality control, recycling system,” says Huihui Li, PhD, a Gladstone postdoctoral scholar and co-first author of the new paper. “We think we’ve uncovered a pathway of mitochondrial recycling—which is like salvaging valuable furniture in a house before demolishing it.”
Importantly, the study shows that the recycling pathway identified by the scientists requires PINK1 and Parkin, supporting that mitochondrial recycling may also be critical in protecting against neurodegeneration in Parkinson’s disease.
“Dopamine neurons that die in Parkinson’s disease are particularly susceptible to mutations in PINK1 and Parkin,” says Nakamura. “Our study advances our understanding of how these two key Parkinson’s disease proteins degrade and recycle mitochondria. Our future studies will investigate how these pathways contribute to disease and how they can be targeted therapeutically.”
Video gaming ‘can increase cognitive ability in children’
Above-average time spent on video games can lead to an increase in IQ over time, a new study reveals
Children who spend an above-average time playing video games can increase their cognitive ability, a new study has revealed.
Researchers at Karolinska Institutet in Sweden have studied how the screen habits of children correlate with how their cognitive abilities develop over time.
While they found that watching television or being on social media had neither a positive or negative effect, video gaming increased their intelligence more than average.
On average, the children spent 2.5 hours a day watching TV, half an hour on social media and one hour playing video games.
The results showed that those who played more games than the average increased their intelligence between the two measurements by approximately 2.5 IQ points more than the average. No significant effect was observed, positive or negative, of TV-watching or social media.
Over 9,000 boys and girls from the United States took part in the study, which saw them perform an array of psychological tests aged nine or ten to determine their cognitive abilities.
The children and their parents were also asked about how much time the children spent watching TV and videos, playing video games and engaging with social media.
Just over 5,000 of the children were followed up after two years, at which point they were asked to repeat the psychological tests. This enabled the researchers to study how the children’s performance on the tests varied from one testing session to the other, and to control for individual differences in the first test.
They also controlled for genetic differences that could affect intelligence and differences that could be related to the parents’ educational background and income.
“We didn’t examine the effects of screen behaviour on physical activity, sleep, wellbeing or school performance, so we can’t say anything about that,” says Torkel Klingberg, professor of cognitive neuroscience at the Department of Neuroscience, Karolinska Institutet.
“But our results support the claim that screen time generally doesn’t impair children’s cognitive abilities, and that playing video games can actually help boost intelligence. This is consistent with several experimental studies of video-game playing.”
The results are also in line with recent research showing that intelligence is not a constant, but a quality that is influenced by environmental factors.
“We’ll now be studying the effects of other environmental factors and how the cognitive effects relate to childhood brain development,” says Prof Klingberg.
GripAble praised by MP
Stephen Hammond MP hails its innovation and “extraordinary” success to date and potential
The progress of GripAble has been hailed as “extraordinary” by its local MP, who praised its innovation and ongoing progress in transforming neurorehab and wider healthcare.
GripAble, the UK technology company digitising upper limb rehabilitation from hospital to home, welcomed Stephen Hammond, MP for Wimbledon, to its international sales and distribution centre.
Mr Hammond visited GripAble’s office in Wimbledon to learn how private equity investment has helped it to scale its industry-leading data platform and therapy services and expand GripAble into Europe and the US, as well as how an international company has successfully stemmed from the local business community.
During his visit, the MP met the GripAble team and listened to a presentation by GripAble co-founder and CEO Dr Paul Rinne, who shared the background to GripAble and its growth story to date, as well as plans and ambitions for the future.
Prior to becoming an MP, Stephen Hammond worked for a leading fund management company and multiple investment banks, so was particularly interested in the funding GripAble has received to date, including the recent close of its $11m funding round.
With more than 8,000 individuals having already used the platform, GripAble has established itself as a leading technology in the remote-rehab space in the UK, recording 100,000 activity sessions and 27 million movement repetitions across its users.
Stephen Hammond MP said: “GripAble proves that innovative companies of the future that are building products that will transform healthcare can be based anywhere, but I’m particularly proud that GripAble has started out in Wimbledon.
“It’s been wonderful to see the development of the company over the last two years since first meeting Paul, and I’m sure the developments over the next three years will be equally extraordinary, particularly with the backing of private equity investment.”
Dr Rinne said: “Today’s visit was a fantastic opportunity for us to showcase GripAble’s story and vision to a Member of Parliament and explain how private equity investment can help UK-based entrepreneurs take ideas from seed stage through to global scaling, and compete on the international stage.
“The investment we have received will accelerate GripAble’s journey to delivering end-to-end patient rehabilitation and connecting millions to their own personal home-based clinic.
“With the backing of investors such as IP Group and Parkwalk, we will benefit from a wealth of insight and experience that will support us in growing our platform in the US and expanding our clinical and commercial evidence base.
“It is great to be able to work with such supportive investors that make our lives so much easier.”
Social media break ‘can improve mental health’
A one-week break can deliver improvements in wellbeing, anxiety and depression, research reveals
A week-long break from social media could lead to significant improvements in wellbeing, depression and anxiety, and could potentially be recommended as a way to help people manage their mental health.
A new study has looked at the effects of taking a break from social media, which for some participants meant sacrificing up to nine hours otherwise spent on Instagram, Facebook, Twitter and TikTok.
The results of the research, from the University of Bath, suggest that after just one week, these individuals saw their overall level of wellbeing improve, as well as reduced symptoms of depression and anxiety.
Over the past 15 years, social media has revolutionised how we communicate, underscored by the huge growth the main platforms have observed.
In the UK the number of adults using social media increased from 45 per cent in 2011 to 71 per cent in 2021. Among 16 to 44-year-olds, as many as 97 per cent of people use social media and scrolling is the most frequent online activity.
Lead researcher from Bath’s Department for Health, Dr Jeff Lambert, explains: “Scrolling social media is so ubiquitous that many of us do it almost without thinking from the moment we wake up to when we close our eyes at night.
“We know that social media usage is huge and that there are increasing concerns about its mental health effects, so with this study, we wanted to see whether simply asking people to take a week’s break could yield mental health benefits.
“Many of our participants reported positive effects from being off social media with improved mood and less anxiety overall. This suggests that even just a small break can have an impact.
“Of course, social media is a part of life and for many people, it’s an indispensable part of who they are and how they interact with others. But if you are spending hours each week scrolling and you feel it is negatively impacting you, it could be worth cutting down on your usage to see if it helps.”
For the study, the researchers randomly allocated 154 individuals aged 18 to 72 who used social media every day into either an intervention group, where they were asked to stop using all social media for one-week or a control group, where they could continue scrolling as normal.
At the beginning of the study, baseline scores for anxiety, depression and wellbeing were taken.
Participants reported spending an average of eight hours per week on social media at the start of the study.
One week later, the participants who were asked to take the one-week break had significant improvements in wellbeing, depression, and anxiety than those who continued to use social media, suggesting a short-term benefit.
Participants asked to take a one-week break reported using social media for an average of 21 minutes compared to an average of seven hours for those in the control group. Screen usage stats were provided to check that individuals had adhered to the break.
The team now want to build on the study to see whether taking a short break can help different populations, such as younger people or people with physical and mental health conditions, who research shows can experience adverse effects at different times.
The team also want to follow people up for longer than one week, to see if the benefits last over time. If so, in the future, they speculate that this could form part of the suite of clinical options used to help manage mental health.
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