Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nuclear transport problems linked to ALS and FTD

19.10.2015

NIH-supported studies point to potential new target for treating neurodegenerative diseases

Three teams of scientists supported by the National Institutes of Health showed that a genetic mutation linked to some forms of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) may destroy neurons by disrupting the movement of materials in and out of the cell's nucleus, or command center where most of its DNA is stored. The results, published in the journals Nature and Nature Neuroscience, provide a possible strategy for treating the two diseases.


A genetic mutation implicated in ALS and FTD prevents proteins (green) from entering and exiting the cell's nucleus (pink).

Photo courtesy of NIGMS. Source: Maximiliano D'Angelo and Martin Hetzer, Salk Institute

"This research shines a spotlight on the role of nuclear transport in the health of neurons," said Amelie Gubitz, Ph.D., program director at the NIH's National Institute of Neurological Disorders and Stroke (NINDS). "The results provide new insights into how this mutation derails an essential process in neurons and opens new avenues for therapy development."

Both ALS and FTD are caused by the death of specific neurons. In ALS, this leads to movement difficulties and eventually paralysis, while in FTD, patients experience problems with language and decision making. Past research has connected a specific mutation in the C9orf72 gene to 40 percent of inherited ALS cases and 25 percent of inherited FTD cases, as well as nearly 10 percent of non-inherited cases of each disorder. The recent experiments, conducted in yeast, fruit flies, and neurons from patients, found that the mutation prevents proteins and genetic material called RNA from moving between the nucleus and the cytoplasm that surrounds it.

... more about:
»DNA »FTD »NINDS »Nuclear »RNA »genes »neurons »proteins »transport problems

"At the end of the day, this culminates in a defect in the flow of genetic information, which leads to problems expressing genes in the right place at the right time," said J. Paul Taylor, M.D., Ph.D., a researcher at St. Jude's Children's Research Hospital in Memphis, Tennessee, and the senior author of one of the papers.

DNA is made up of building blocks called nucleotides. In the mutated C9orf72 gene, a sequence of six nucleotides is repeated many times more than are typical. These repetitive stretches of DNA produce RNA molecules that can interfere with proteins in the cell. The RNA also generates toxic proteins called dipeptide repeat proteins. However, until now, it was unknown what specific cellular systems were impaired by these two products of the mutation.

All three groups of scientists found evidence that the mutation impairs nuclear transport in neurons grown from patients' skin cells. Dr. Taylor's team showed that these neurons have much more RNA in the nucleus compared to those created from healthy control cells, implying that the mutation prevents RNA from leaving the nucleus. The other two groups discovered that the patient-derived neurons had trouble bringing certain proteins into the nucleus as well.

Researchers led by Jeffrey Rothstein, M.D., Ph.D., from Johns Hopkins University in Baltimore focused on how the abnormal RNA produced by the C9orf72 mutation affects a protein called RanGAP, which is essential for transporting materials into the nucleus. Building on previous work, the group confirmed that the RNA strands bind to RanGAP in brain tissue from patients with the mutation and stop the protein from performing its function. The team then treated those cells with compounds that prevented this interference and found that this eliminated the transport defect, allowing proteins to get inside the nucleus. Similarly, increasing production of RanGAP in fruit flies reduced neuronal deterioration and motor problems caused by the mutation.

"This research defines the tipping point for how both ALS and FTD start, which is the interruption of nuclear-cytoplasmic transport," Dr. Rothstein said. "By examining a combination of fly models, living human brain cells, and real human tissue from autopsies, these studies comprehensively teach us what starts the disease."

In addition to their work with the lab-grown neurons, Dr. Taylor's team explored the mutation's effects by inserting eight, 28, or 58 copies of the repetitive DNA sequence into fruit fly neurons. They found that additional copies caused more harm to the cells. The group then performed a genetic "screen" in which they systematically mutated other fly genes to find ones that increased or decreased this damage. Many of the genes they found code for nuclear transport proteins, which regulate the movement of molecules in and out of the nucleus.

"We were really amazed to find 18 genes that relate to nucleocytoplasmic trafficking, so we knew that we were onto something that was a very strong hit," Dr. Taylor said.

Meanwhile, a third team of researchers led by Stanford University's Aaron Gitler, Ph.D., performed similar screens in yeast cells containing the toxic dipeptide repeat proteins produced by the C9orf72 mutation. As in Dr. Taylor's study, these experiments suggested that genes involved in nuclear transport influence how harmful the dipeptide repeat proteins are to the cells.

"It's encouraging that multiple groups, using independent approaches, have all converged on the same genes and pathways," Dr. Gitler said.

Taken together, the three studies suggest that therapies designed to increase nucleocytoplasmic transport may be effective for treating some forms of ALS and FTD.

###

The work was supported by the NIH (NS085207, NS091046, NS082563, NS074324, NS089616, NS091486, NS079725, NS065317, NS073660, GM084947, CA009110, AG019724, and OD081537); the Robert Packard Center for ALS Research at Johns Hopkins University; the Muscular Dystrophy Association; the Alzheimer's Drug Discovery Foundation; the Judith and Jean Pape Adams Charitable Foundation; the Alzheimer's Disease Research Center at Johns Hopkins; the Maryland Technology Development Corporation (TEDCO); Target ALS; the William and Ella Owens Foundation; the ALS Association; the KU Leuven; the European Research Council; the Fund for Scientific Research Flanders; the Interuniversity Attraction Poles Programme; the Association Belge contre les Maladies Neuro-Musculaires (ABMM); the ALS Liga; and the 'Opening the Future' Fund.

References:

Zhang et al. "The C9orf72 repeat expansion disrupts nucleocytoplasmic transport," Nature, August 26, 2015. DOI: 10.1038/nature14973.

Freibaum et al. "GGGGCC repeat expansion in C9orf72 compromises nucleocytoplasmic transport," Nature, August 26, 2015. DOI: 10.1038/nature14974.

Jovicic et al. "Modifiers of C9orf72 dipeptide repeat toxicity connect nucleocytoplasmic transport defects to FTD/ALS," Nature Neuroscience, August 26, 2015. DOI: 10.1038/nn.4085.

NINDS is the nation's leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease.

About the National Institute on Aging: The NIA leads the federal government effort conducting and supporting research on aging and the health and well-being of older people. It provides information on age-related cognitive change and neurodegenerative disease specifically at its Alzheimer's Disease Education and Referral (ADEAR) Center at http://www.nia.nih.gov/Alzheimers. Information on health and on aging generally can be found at http://www.nia.nih.gov/

The National Institute of General Medical Sciences (NIGMS) supports basic research that increases understanding of biological processes and lays the foundation for advances in disease diagnosis, treatment and prevention. NIGMS-funded scientists investigate how living systems work at a range of levels, from molecules and cells to tissues, whole organisms and populations. The Institute also supports research in certain clinical areas, primarily those that affect multiple organ systems. To assure the vitality and continued productivity of the research enterprise, NIGMS provides leadership in training the next generation of scientists, in enhancing the diversity of the scientific workforce, and in developing research capacities throughout the country. More information about NIGMS can be found at http://www.nigms.nih.gov/Pages/default.aspx.

The National Cancer Institute leads the National Cancer Program and the NIH's efforts to dramatically reduce the prevalence of cancer and improve the lives of cancer patients and their families, through research into prevention and cancer biology, the development of new interventions, and the training and mentoring of new researchers. For more information about cancer, please visit the NCI website at http://www.cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

Media Contact

NINDS Press Team
nindspressteam@ninds.nih.gov
301-496-5751

 @NINDSnews

http://www.ninds.nih.gov 

NINDS Press Team | EurekAlert!

Further reports about: DNA FTD NINDS Nuclear RNA genes neurons proteins transport problems

More articles from Health and Medicine:

nachricht NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University

nachricht How to turn white fat brown
07.12.2016 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>