A rare genetic disorder called tuberous sclerosis complex (TSC) is yielding insight into a possible cause of some neurodevelopmental disorders: structural abnormalities in neurons, or brain cells. Researchers in the F.M. Kirby Neurobiology Center at Children’s Hospital Boston, led by Mustafa Sahin, MD, PhD, and Xi He, PhD, also found that normal neuronal structure can potentially be restored.
If this could be done safely in humans, it might be possible to ameliorate the symptoms of epilepsy, mental retardation and autism, which are frequent complications of TSC, say the researchers. Their findings, accompanied by commentary, were the cover article of the September 15 issue of Genes & Development.
TSC causes benign tumor-like lesions, which can affect every organ in the body and are called tubers when they occur in the brain. In the study, Sahin, He, lead author Yong-Jin Choi, PhD, and colleagues show in mice that when the two genes linked to the disease, TSC1 and TSC2, are inactivated, neurons grow too many axons (the long nerve fibers that transmit signals). Normal neurons grow just one axon and multiple dendrites (short projections that receive input from other neurons). This specification of axons and dendrites, known as polarity, is crucial for proper information flow.
“We think if initial polarity is not formed properly, the result will be abnormal connectivity in the brain,” says Sahin, who also directs the clinical Multi-Disciplinary Tuberous Sclerosis program at Children’s.
Since autism occurs in about half of people with TSC, the findings support the idea that such miswiring causes or contributes to autism, Sahin adds. He has received funding from Autism Speaks, the Manton Foundation and the Tuberous Sclerosis Alliance to pursue this idea further.
“People have started to look at autism as a developmental disconnection syndrome – there are either too many connections or too few connections between different parts of the brain,” Sahin says. “In mouse models of TSC, we’re seeing an exuberance of connections.”
In laboratory experiments, the researchers were able to limit multiple axon formation by using the cancer drug rapamycin to suppress production of a protein called SAD-A kinase. This protein is produced in excess when the TSC1 and TSC2 genes are inactivated, and is found in abundance in the abnormally large cells that make up tubers.
Because increased SAD-A is associated with increased axon growth, the researchers also speculate that the TSC pathway could be manipulated to regenerate or repair axons lost or damaged in spinal cord or other nerve injuries.
“These findings provide a potential explanation for neurological abnormalities in TSC patients and perhaps in people without TSC,” says He. “The challenge remains as to how to treat these conditions. We have some clues but a lot more research needs to be done.”
The study was funded by grants from the Tuberous Sclerosis Alliance, the Manton Foundation, the Hearst Fund and the National Institutes of Health.
The paper can be downloaded free of charge at: http://genesdev.cshlp.org/cgi/content/abstract/22/18/2485?ijkey=949b2a5281a96ef468052b08e52e9cab65db1470&keytype2=tf_ipsecsha.
Children's Hospital Boston is home to the world's largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults since 1869. More than 500 scientists, including eight members of the National Academy of Sciences, 11 members of the Institute of Medicine and 12 members of the Howard Hughes Medical Institute comprise Children's research community. Founded as a 20-bed hospital for children, Children's Hospital Boston today is a 397-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children's also is the primary pediatric teaching affiliate of Harvard Medical School.
James Newton | Newswise Science News
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences