A paper published online today in Nature describes the results of using bone marrow transplant (BMT) to replace faulty immune system cells in models of Rett Syndrome. The procedure arrested many severe symptoms of the childhood disorder, including abnormal breathing and movement, and significantly extended the lifespan of Rett mouse models.
Exploring the function of microglia deficient in methyl-CpG binding protein 2 (Mecp2), the protein encoded by the "Rett gene," principal investigator Jonathan Kipnis, Ph.D. and his team at the University of Virginia School of Medicine uncovered a completely novel approach to this devastating neurological syndrome. The work was funded by the Rett Syndrome Research Trust and the Rett Syndrome Research Trust UK.
Rett Syndrome, the most physically disabling of the autism spectrum disorders, is caused by random mutations in the gene MECP2. Predominantly affecting girls, symptoms usually manifest between 6 and 18 months of age, when a frightening regression begins. Children lose acquired language skills and functional hand use; movement deteriorates as other Rett symptoms appear. These may include disordered breathing, Parkinsonian tremors, severe anxiety, seizures, digestive and circulatory problems and a range of autonomic nervous system and orthopedic abnormalities Although most children survive to adulthood, many are wheelchair-bound, rely on feeding tubes, are unable to communicate and require total, lifelong care.
Kipnis was drawn to Rett Syndrome from his perspective as a neuroimmunologist. "What began as intellectual curiosity," he explains, "has become an intense personal commitment to studying the correlation between neurological function and the immune system in Rett Syndrome. The impact of BMT on so many different symptoms has triggered a flood of experiments we are now pursuing at full speed."
The brain is largely comprised of several types of glial cells, which have diverse and complex functions that include sustaining a healthy environment for neuronal growth and maintenance. Microglia are small glial cells that participate in the brain's immune response. One of their roles is to clean up normal cellular debris in the brain through the process of phagocytosis. Kipnis and his team discovered that when microglia lack properly functioning Mecp2, they are unable to perform this crucial duty efficiently. Because microglia are derived from immune progenitor cells, it is possible to replace them via a bone marrow transplant.
First author Noël Derecki and his colleagues began their work with male Rett mouse models, which lack any Mecp2. These Mecp2-null mice mimic the human disorder, with neurological symptoms beginning to appear at about 4 weeks of age and an approximate life expectancy of only 8 weeks. Radiation treatment was administered at 4 weeks, followed by a bone marrow transplant from normal (wild-type) mice. As engraftment - the migration and repopulation of new microglia - took place, the Rett mice began to grow instead of fail. Body and brain sizes approached those of wild-type mice, gait improved and mobility increased significantly. There were no signs of the severe tremors seen in untreated mice. Apneas and other breathing irregularities were markedly diminished. The oldest of these mice is now almost a year. Work with female Rett mouse models at more advanced stages of disease is currently underway.
Gail Mandel, Ph.D., whose Rett research focuses on astrocytes, another type of glial cell impaired by mutations in MECP2, comments, "A fascinating aspect of these findings is the data suggesting that deficits in the engulfing properties of microglia are a crucial aspect of Rett neuropathology. It will now be necessary to develop cellular assays to determine all the ways these immune cells are bolstering neuronal functions and whether they can be therapeutically harnessed." Dr. Mandel is a Senior Scientist at the Vollum Institute and a Professor in the Department of Biochemistry and Molecular Biology in the School of Medicine at Oregon Health & Science University and an Investigator of the Howard Hughes Medical Institute.
Monica Coenraads, Executive Director of the Rett Syndrome Research Trust added, "I've been in almost daily contact with Dr. Kipnis since he brought his very original proposal to RSRT, and have been amazed to see the development of this brutal disease stopped in its tracks. A question that arises, of course, is whether replacing faulty immune cells with healthy microglia through bone marrow transplant would arrest or ameliorate already existing symptoms in humans. We do know of a case in which a girl with Rett Syndrome who was treated for leukemia gained considerable communication skills after a bone marrow transplant, and was able to converse with her mother for the first time in their lives. RSRT is in the process of exploring bone marrow transplant as a treatment modality, with full awareness of the serious nature of such a trial. In research, we are risk-takers. In clinical application, we are conservative and will be examining this carefully as more information emerges."
Adds Noël Derecki, "Our encouraging results point to how surprisingly tractable this severe disorder proves to be, at least in the lab. We are currently exploring how bone marrow transplantation might affect Rett symptoms once they have become more advanced, and whether there are other effective ways of modulating immune responses and subsequent effects in the central nervous system."
The paper, authored by Noël C. Derecki, James C. Cronk, Zhenjie Lu, Eric Xu, Stephen B.G. Abbott, Patrice G. Guyenet and Jonathan Kipnis, is entitled Wild type microglia arrest pathology in a mouse model of Rett Syndrome. doi:10.1038/nature10907
About the Rett Syndrome Research Trust
The Rett Syndrome Research Trust is the premier organization exclusively devoted to global research on Rett Syndrome and related MECP2 disorders. Our goal is to heal children and adults who will otherwise suffer the effects of these disorders for the rest of their lives. To learn more about the Trust, please visit www.ReverseRett.org
Our partners in supporting this work are parents' organizations worldwide including the Rett Syndrome Research & Treatment Foundation (Israel), Stichting Rett Syndrome (Holland), Rett Syndrom Deutschland e.V., Skye Wellesley Foundation (UK) and American organizations, The Kate Foundation for Rett Syndrome Research, Girl Power 2 Cure and Rocky Mountain Rett Association.
Monica Coenraads | EurekAlert!
Inhaling air pollution-like irritant alters defensive heart-lung reflex for hypertension
19.06.2019 | University of South Florida (USF Innovation)
Nitric oxide-scavenging hydrogel developed for rheumatoid arthritis treatment
06.06.2019 | Pohang University of Science & Technology (POSTECH)
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.
The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
19.06.2019 | Physics and Astronomy
19.06.2019 | Information Technology
19.06.2019 | Materials Sciences