Breaking News
May 26, 2018 - Lifetime risks of developing Alzheimer’s dementia vary by age, gender
May 26, 2018 - Researchers find novel ways to improve participation in clinical research
May 26, 2018 - Researchers develop methods for measuring free-base nicotine levels in e-cigarettes
May 26, 2018 - AHA: Preterm Birth Could Warn of Mom’s Future Heart Risks
May 26, 2018 - Some calories more harmful than others
May 26, 2018 - Study links cell size with commitment to division
May 26, 2018 - Researchers develop new, rapid blood test to detect liver damage
May 26, 2018 - Researchers discover cascade of immune processes linked to poor outcomes in aggressive breast cancer
May 26, 2018 - New research will use mathematics to solve mysteries in cell biology
May 26, 2018 - Mice remain slim on burger diet
May 26, 2018 - BMC receives $13.5 million award to test methods for delivering childhood anxiety treatment
May 26, 2018 - ‘Right to Try Act’ will not benefit terminally-ill patients
May 26, 2018 - Study reveals novel statistical algorithm to identify potential disease genes
May 26, 2018 - Two genes play vital roles in malignant brain cancer
May 26, 2018 - Study explores link between groundwater lithium and diagnoses of bipolar disorder, dementia
May 26, 2018 - Researchers reveal stimulatory effects of myelin on young neural cells
May 26, 2018 - Small part of cellular protein that helps form long-term memories also drives neurodegeneration
May 26, 2018 - Four-legged friends can have heart issues, too
May 26, 2018 - Scientists create small, self-contained spaces inside mammalian cells
May 26, 2018 - Better Social Support Network Protects Black Men Against HIV
May 26, 2018 - National Heart, Lung, and Blood Institute (NHLBI)
May 26, 2018 - Burnout, depression can affect ophthalmology residents, study finds
May 26, 2018 - Latinos and African Americans more likely to experience serious depression than Whites
May 26, 2018 - Data from past epidemic could help improve response to future Ebola outbreaks
May 26, 2018 - Researchers provide insight into how the memory molecule limits brain plasticity
May 26, 2018 - OSU biologist describes ‘restoration ecology’ approach toward patient health
May 26, 2018 - New approach to study brown fat could aid in finding treatments for obesity
May 26, 2018 - Could More Fish in the Diet Boost Sex Lives and Fertility?
May 26, 2018 - NTU Singapore and SERI invent new scope to diagnose glaucoma
May 26, 2018 - Cancer cells co-opt pain-sensing ‘neural channel’ to increase tolerance against oxidative stress
May 26, 2018 - Study uncovers why pesticide exposure increases Parkinson’s disease risk in some people
May 26, 2018 - Study finds link between lead exposure and fertility rates
May 26, 2018 - Delivery of standardized diabetes care could help achieve equitable health outcomes for all patients
May 26, 2018 - FDA authorizes marketing of OsteoDetect software for detecting wrist fractures
May 26, 2018 - Children and adolescents growing up in extreme societal conditions more likely to resort to violence
May 26, 2018 - New study puts forth most comprehensive tree of life for malaria parasites
May 26, 2018 - UVA researchers establish new guidelines for explorers of the submicroscopic world inside us
May 26, 2018 - Princeton Instruments and C-SOPS announce collaboration on innovative pharmaceutical technology
May 26, 2018 - New research shows why babies need to move in the womb
May 26, 2018 - UK steps forward to tackle global antimicrobial resistance
May 26, 2018 - CRISPR-Cas9-based strategy allows researchers to precisely alter hundreds of different genes
May 26, 2018 - Novoheart announces next generation of ‘Human heart-in-a-jar’ technology for advanced drug discovery
May 26, 2018 - UT Southwestern-led researchers find new way to determine prognosis of invasive kidney cancer
May 26, 2018 - Researchers develop film to prevent bacteria from growing on dental retainers and aligners
May 26, 2018 - Mobile health intervention for people with serious mental illness as effective as clinic-based treatment
May 26, 2018 - Vaginal estradiol tablets outperform moisturizers when treating vulvovaginal problems
May 26, 2018 - Researchers call for new genetic tests for congenital diseases
May 26, 2018 - KHN’s ‘What the Health?’ Campaign promises kept, plus ‘nerd reports’
May 26, 2018 - AARDA collaborates with Allegheny Health Network and new AHN Autoimmunity Institute
May 26, 2018 - Lung-on-a-chip technology could streamline drug-testing for pulmonary fibrosis
May 26, 2018 - Researchers work together to solve mystery of motor neuron death in ALS patients
May 26, 2018 - Study finds early antibiotic initiation for majority of premature infants
May 26, 2018 - New environmental monitoring project finds increased numbers of deer ticks in Southern Indiana
May 26, 2018 - Pediatricians Should Advocate for Life Support Training
May 26, 2018 - Cannabidiol significantly reduces seizures in patients with severe form of epilepsy
May 26, 2018 - Allergies can have serious, far-reaching consequences on adolescents
May 26, 2018 - Scientists develop lab-based system to study mechanisms of common liver disease
May 25, 2018 - New guidelines may help pathologists to more accurately classify and diagnose invasive melanoma
May 25, 2018 - Immune cells promote lung cancer metastases by forming clots in tumors, study finds
May 25, 2018 - Can Excess Weight in Toddlers Cause Brain Drain?
May 25, 2018 - Studying insight
May 25, 2018 - Researchers reveal potent new mechanism of action for treatment of IBD
May 25, 2018 - Study shows lack of follow-up care for patients with concussion
May 25, 2018 - Study establishes the importance of haploid cells
May 25, 2018 - Coveted BMJ award bestowed on The Clatterbridge Cancer Center
May 25, 2018 - AACN outlines evidence-based protocols and clinical strategies to manage alarms
May 25, 2018 - Origami inspires researchers to develop new solution for tissue regeneration
May 25, 2018 - Melorheostosis – Genetics Home Reference
May 25, 2018 - Non-addictive pain medication changing therapy for substance use disorders
May 25, 2018 - Delayed lactate measurements in sepsis patients increase risk of in-hospital death
May 25, 2018 - Researchers identify novel epigenetic mutations as cause of neurodevelopmental, congenital disorders
May 25, 2018 - UD researchers examine connection between DNA replication in HPV and cancer
May 25, 2018 - Researchers identify neurons that play key role in aggressive behavior
May 25, 2018 - Snail’s eye inspires new type of RIOCATH urinary catheter
May 25, 2018 - Russian researchers develop high-tech device-transformer for ultrasound examination
May 25, 2018 - Researchers discover unexpected chemosensor pathway for predator odor-evoked innate fear behaviors
May 25, 2018 - Researchers build 3-D printer that offers sweet solution to making detailed structures
May 25, 2018 - Nearly one in three people know someone addicted to opioids
May 25, 2018 - Research suggests link between faulty gene, alcohol, and heart failure
May 25, 2018 - New findings could help fine-tune treatment for cancer patients
Large ALS-causing protein aggregates protect rather than harm neurons

Large ALS-causing protein aggregates protect rather than harm neurons

image_pdfDownload PDFimage_print

Scientists at the UNC School of Medicine have made a significant advance in the understanding of the complex and fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease.

Autopsy studies of ALS patients often reveal the accumulation of large, fibrous aggregates of a protein called SOD1 in disease-affected motor neurons. Researchers have hypothesized that these fibrils are what kill neurons and cause ALS in some people. But in a study published in the Proceedings of the National Academy of Sciences, scientists at the University of North Carolina at Chapel Hill found evidence that these large SOD1 fibrils protect rather than harm neurons.

“This is potentially an important finding not only for ALS research but for neurodegenerative disease research in general, because the formation of fibril aggregates is so common in these diseases,” said senior author Nikolay Dokholyan, PhD, the Michael Hooker Distinguished Professor of Biochemistry and Biophysics at UNC-Chapel Hill.

Large, often fibril-type protein aggregates are in fact the most obvious pathological features of Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, ALS, and other major neurodegenerative diseases. Many of the candidate drugs developed in recent years were designed to clear these protein aggregates. But none of these fibril-targeting strategies have proven effective in large clinical trials. Laboratory studies also have largely failed to prove that large SOD1 fibrils are harmful to neurons.

At the same time, researchers have found that much smaller protein clusters called oligomers – made of only a few copies of these proteins – can be highly toxic to motor neuron-like cells grown in the lab and thus are more likely to be the chief causes of brain-cell death in these diseases.

In a 2016 study, for example, Dokholyan’s lab found evidence that “trimer” structures made of just three copies of the SOD1 protein are toxic to the type of neuron affected in ALS.

For the new study, Dokholyan’s team, including lead author Cheng Zhu, PhD, a postdoctoral researcher in his lab, conducted complicated experiments to compare how trimers affect neurons to how larger fibrils affect neurons.

“One challenge is that the smaller structures such as trimers tend to exist only transiently on the way to forming larger structures,” Zhu said. “But we were able to find an SOD1 mutation that stabilizes the trimer structure and another mutation that promotes the creation of the larger fibrils at the expense of smaller structures. So, we were able to separate the effects of these two species of the protein.”

The researchers expressed the mutant SOD1 proteins in test cells that closely resemble the muscle-controlling neurons killed in ALS. They found – as they did in the 2016 study – that when these cells expressed SOD1 mutants that predominantly form trimers, the cells died much more quickly than control cells containing normal SOD1. The trimer-expressing cells even died more quickly than cells expressing mutant forms of SOD1 that are found in severe hereditary ALS cases.

“Looking at various SOD1 mutants, we observed that the degree of toxicity correlated with the extent of trimer formation,” Zhu said.

On the other hand, the viability of cells containing mutant SOD1 that strongly forms fibrils but suppresses trimers tended to be similar as wild-type SOD1, suggesting that the fibrils are protective, not merely less toxic.

This suggests SOD1 fibrils aren’t the problem in SOD1-linked ALS; they might be a solution. “Taking a drug to promote fibril formation could be one way to reduce toxicity in SOD1-ALS,” Dokholyan said.

An alternative strategy, he noted, would be to limit the formation of trimers or other small, toxic SOD1 oligomers. SOD1 normally works in cells as a two-copy structure, a dimer. Trimers and other abnormal structures appear to originate when the dimers fall apart. So Dokholyan and colleagues are looking for potential drug molecules that can stabilize the dimers.

SOD1 is linked to a significant proportion of ALS cases. Mutations in the SOD1 gene account for about 12 percent of ALS cases that run in families. All of these mutations destabilize the protein’s normal structure and promote abnormal SOD1 structures. SOD1 mutations also appear to account for about 1.5 percent of cases that do not obviously run in families.

“Although SOD1-associated ALS represents a small fraction of all ALS cases, uncovering the origins of neurotoxicity in SOD1 aggregation may shed light on the underlying causes of an entire class of neurodegenerative diseases,” Dokholyan said.

The next steps for Dokholyan’s lab is to pinpoint downstream cellular mechanisms of toxicity of pathological trimeric SOD1 and find drugs that mitigate the formation of trimers.

Source:

https://www.unchealthcare.org/

Tagged with:

About author

Related Articles