News Releases News Topics Media Advisories University Statements Study: Memory deficits resulting from epigenetic changes in Alzheimer’s disease can be reversed
Memory loss associated with Alzheimer’s disease (AD) may be able to be restored by inhibiting certain enzymes involved in abnormal gene transcription, according to a preclinical study by researchers at the University at Buffalo. The findings could pave the way toward new treatments for Alzheimer’s disease.
The paper will be published in Science Advances.
“By treating AD mouse models with a compound to inhibit these enzymes, we were able to normalize gene expression, restore neuronal function, and ameliorate cognitive impairment,” said Zhen Yan, PhD, senior author and SUNY Distinguished Professor in the Department of Physiology and Biophysics in the Jacobs School of Medicine and Biomedical Sciences at UB.
Alzheimer’s disease alters the expression of genes in the prefrontal cortex, a key region of the brain controlling cognitive processes and executive functions.
By focusing on gene changes caused by epigenetic processes (those that are not related to changes in DNA sequences) such as aging, the UB researchers were able to reverse elevated levels of harmful genes that cause memory deficits in AD.
The current research extends the work the UB team reported in 2019 in the journal Brain, in which they were able to reverse the loss or downregulation of genes beneficial to cognitive function in AD.
In this new paper, the UB team reports that it has reversed the upregulation of genes involved in impairing cognitive function.
Packaging the DNA
Yan explained that transcription of genes is regulated by an important process called histone modification, where histones, the proteins that help package DNA into chromosomes, are modified to make that packaging looser or tighter. The nature of the packaging, in turn, controls how genetic material gains access to a cell’s transcriptional machinery, which can result in the activation or suppression of certain genes.
Yan said they found that H3K4me3, a histone modification called histone trimethylation at the amino acid lysine 4, which is linked to the activation of gene transcription, is significantly elevated in the prefrontal cortex of people with AD and mouse models of the disease.
That epigenetic change, she said, is linked to the abnormally high level of histone-modifying enzymes that catalyze the modification known as H3K4me3.
The UB researchers found that when the AD mouse models were treated with a compound that inhibits those enzymes, they exhibited significantly improved cognitive function.
“This finding points to the potential of histone modifying enzyme-targeted drugs for AD treatment, which may have broad and powerful impact,” said Yan.
New target genes
In making that discovery, the UB team also identified a number of new target genes, including Sgk1 as a top-ranking target gene of the epigenetic alteration in AD. Sgk1 transcription is significantly elevated in the prefrontal cortex of people with AD and in animal models with the disorder.
Yan said they found that abnormal histone methylation at Sgk1 contributes to its elevated expression in AD. “Interestingly, the upregulation of Sgk1 is also strongly correlated with the occurrence of cell death in other neurodegenerative diseases, including Parkinson’s disease and amyotrophic lateral sclerosis,” she said.
Sgk1 encodes an enzyme activated by cell stress, which plays a key role in numerous processes, such as regulating ion channels, enzyme activity, gene transcription, hormone release, neuron excitability and cell death. The researchers found that it is highly connected to other altered genes in AD, suggesting it may function as a kind of hub that interacts with many molecular components to control disease progression.
“In this study, we have found that administration of a specific Sgk1 inhibitor significantly reduces the dysregulated form of tau protein that is a pathological hallmark of AD, restores prefrontal cortical synaptic function, and mitigates memory deficits in an AD model,” she said. “These results have identified Sgk1 as a potential key target for therapeutic intervention of AD, which may have specific and precise effects.”
‘Junk DNA’ plays a key role in regulating circadian clocks
If you’ve ever had a bad case of jet lag, you know how a disruption to your body’s circadian rhythm makes it difficult to function. Molecular circadian “clocks” exist in cells throughout the body, governing more than just sleep and wake cycles — they are crucial to many aspects of human health. For more than a decade, researchers have been trying to figure out what makes them tick, in search of new insights into diseases like Alzheimer’s, cancer and diabetes.
Until now, that research has focused on what is known as clock genes, which encode proteins that drive oscillating cycles of gene expression affecting physiology and behavior. But research just published in the Proceedings of the National Academy of Sciences reveals the discovery of a new cog in the circadian clock — a genome-wide regulatory layer made up of small chains of non-coding nucleotides known as micro RNAS (miRNAs).
“We’ve seen how the function of these clock genes are really important in many different diseases,” said Steve Kay, PhD, Provost Professor of neurology, biomedical engineering and quantitative computational biology at the Keck School of Medicine of USC. “But what we were blind to was a whole different funky kind of genes network that also is important for circadian regulation and this is the whole crazy world of what we call non-coding microRNA.”
‘Junk DNA’ proves to be a valuable tool in circadian rhythms
Formerly thought to be “junk DNA,” miRNAs are now known to affect gene expression by preventing messenger RNA from making proteins. Past research has indicated miRNAs may have a role in the function of circadian clocks but determining which of the hundreds of miRNAs in the genome might be involved remained a problem.
Kay and his team, led by Lili Zhou, a research associate in the Keck School’s Department of Neurology, turned to the Genomics Institute of the Novartis Research Foundation (GNF) in San Diego, which has created robots capable of high throughput experiments. Working with scientists at the institute, Zhou developed a high throughput screen for a robot to test the close to 1000 miRNAs by individually transferring them into cells the team had engineered to glow on and off, based on the cell’s 24-hour circadian clock cycle.
“The collaboration with GNF made it possible for us to conduct the first cell-based, genome-wide screening approach to systematically identify which of the hundreds of miRNAs might be the ones modulating circadian rhythms,” said Zhou.
“Much to our surprise,” said Kay, “we discovered about 110 to 120 miRNAs that do this.”
With the help of Caitlyn Miller, a biochemistry undergraduate from USC Dornsife, researchers then verified the impact on circadian rhythms by inactivating certain miRNAs identified by the screen in their line of glowing cells. Knocking out the miRNAs had the opposite effect on the cells’ circadian rhythm as adding them to the cells.
Physiologic and behavioral impacts of miRNAs
Researchers also focused on the physiologic and behavioral impacts of miRNAs. They analyzed the behavior of mice with a particular cluster of miRNAs inactivated – miR 183/96/182 – and saw that inactivating the cluster interfered with their wheel-running behavior in the dark compared with control mice. They then examined the impact of the miRNA cluster on brain, retina and lung tissue, and found that inactivating the cluster affected circadian rhythms in a different way in each tissue type – suggesting that the way the miRNAs regulate the circadian clock is tissue specific.
Understanding the impact of miRNAs on the circadian clock in individual tissue could reveal new ways of treating or preventing specific diseases.
“In the brain we’re interested in connecting the clock to diseases like Alzheimer’s, in the lung we’re interested in connecting the clock to diseases like asthma,” said Kay. “The next step I think for us to model disease states in animals and in cells and look at how these microRNAs are functioning in those disease states.”
Samsung Galaxy F62, Samsung Galaxy M02 Spotted on India Support Page; Hints at Imminent Launch
Samsung Galaxy F62 and Samsung Galaxy M02 have leaked in the past on several occasions, and now the model numbers associated with these phones have been spotted on Samsung’s official support page in India as well. This indicates that both the phones’ launches could be inching closer and Samsung is gearing up to introduce them in the Indian market. Samsung Galaxy F62 is also reported to be called the Samsung Galaxy E62. In some markets, this phone may likely be also called the Samsung Galaxy M62.
MySmartPrice spotted two model numbers – SM-E625F/DS and SM-M022G/DS – on the Samsung India support page. The support page doesn’t offer any details about the phone, and it doesn’t even reveal the commercial name of the phone, but the SM-E625F/DS model number is largely associated with Samsung Galaxy F62, or Samsung Galaxy E62, in the past. Likewise, the SM-M022G/DS is associated with the anticipated Samsung Galaxy M02 handset.
Samsung introduced the Galaxy M02s in the Indian market earlier this month, but the Galaxy M02 still remains in the rumour mill. As per a Geekbench listing, Samsung Galaxy M02 may run on Android 10 and come with 3GB of RAM. The smartphone could also come with the Qualcomm Snapdragon SoC that is clocked at 1.8GHz.
The rumoured Samsung Galaxy F62 has also leaked in images, hinting at a square shaped module on the back. The phone has also been spotted on BIS website and an earlier report also claims that the production of the rumoured Samsung Galaxy F62 has begun at the company’s Greater Noida facility in the Delhi-NCR region. The Galaxy F62 could be one of the slimmest phones from Samsung and it is expected to launch in the first quarter of 2021. Specifications leaked in the past include Exynos 9825 SoC, have 6GB of RAM and Android 11.
Is this the end of the Samsung Galaxy Note series as we know it? We discussed this on Orbital, our weekly technology podcast, which you can subscribe to via Apple Podcasts, Google Podcasts, or RSS, download the episode, or just hit the play button below.
The new Microsoft Edge browser will warn you if your password has been leaked online
The new Edge 88 browser includes tough new security features, including a password generator and a tool for monitoring whether your login details have been exposed to the dark web.
Microsoft Edge 88 is rolling out to users in the Stable channel alongside some new privacy-focused features, including a long-awaited credentials monitor and a built-in password generator.
The first of these features, Password Monitor, will help users stay protected against data breaches involving passwords. If Edge determines that a user’s login credentials have been exposed on the dark web (or elsewhere), it will notify them within the browser and advise them to update their passwords.
SEE: Identity theft protection policy (TechRepublic Premium)
Password monitor was
and began rolling out yesterday (January 21) with the release of Edge 88, though it may take a week or two to reach Edge users, Microsoft said.
The latest version of Microsoft Edge, which is based on the open-source Chromium architecture, also features a built-in password generator. When users sign up to a new account on a website, Edge will automatically generate a strong password for the user, which is then automatically saved and synced across their devices.
The feature is similar to the one available on Google Chrome, and helps ensure users are using strong passwords for their accounts, while taking away the onus of having to memorize (or worse, write down) lists of complex, unique passwords for each service they sign up for. This is particularly important when creating accounts for financial services and other websites that require valuable information, Microsoft said.
Password Monitor is available for Windows 7, 8 and 10 users. Password Generator is available to the same Windows users, in addition to being available on macOS. Both features require users to be signed into Edge with a work or school account, and password sync turned on.
Microsoft has made additional privacy tweaks under the hood of Edge 88. This includes more transparent options around data collection, with users now able to dip into the permissions settings and control which sites have access to location, camera and microphone functions. Customers also have more control over how cookies are stored, specifically by allowing them to delete unnecessary third-party cookies while hanging onto ones they want to keep: say, for keeping certain settings in place for websites they visit regularly.
SEE: Top Windows 10 run commands (free PDF) (TechRepublic)
Edge 88 also adds features for making browsing in private mode even more private. Users can now toggle a ‘Strict’ mode within the InPrivate browser that will block any trackers that personalize content and ads. This will prevent users from being shown personalized ads based on their browsing history, which Microsoft said would be useful when shopping for gifts or planning a surprise. This could be inadvertently ruined by an ad that gives the game away, particularly on a shared computer.
For times when even more privacy is needed, Microsoft Edge 88 features Secure DNS. This bolsters security by looking up website addresses over the more secure HTTPS protocol, ensuring data remains encrypted and protecting it from attackers who might try to modify or eavesdrop on the connection.
Users can configure a different secure DNS provider or disable it altogether within the Edge 88 privacy settings. Strict mode and Secure DNS is available on Edge 88 for Windows 7, 8 and 10 users, and on macOS.
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