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microglia cells damage the myelin sheath of neuron axons

Katrina Adams, Ph.D., awarded fellowship to help restore functions in MS patients

microglia cells damage the myelin sheath of neuron axons

Multiple sclerosis is a demyelinating disease in which the insulating covers of nerve cells are damaged. Microglia cells (orange) attack the oligodendrocytes that form the insulating myelin sheath around neuron axons, leading to the destruction of the myelin sheath and to the loss of nerve function.

For her contributions to Multiple Sclerosis (MS) research, Katrina Adams, Ph.D., postdoctoral researcher at Children’s National Hospital, received the career transition fellowship from The National Multiple Sclerosis Society. The $600,000 fellowship will support a two-year period of advanced postdoctoral training in MS research and the first three years of research support in a new faculty appointment.

MS symptoms, including vision loss, pain, fatigue and reduced motor coordination, result from the demyelination of neuronal axons that transport critical information across the brain and spinal cord. Demyelination is the loss of myelin protein, which is normally produced by oligodendrocyte cells.

In the healthy brain, oligodendrocytes repair demyelinated areas by replacing damaged or lost myelin in a process called remyelination. Recent evidence has shown that oligodendrocytes display differences in their molecular and functional properties. One source of new oligodendrocytes in the adult brain is neural stem cells, which have been shown to generate oligodendrocytes that contribute to remyelination.

“The goal of this project is to determine whether neural stem cell-derived oligodendrocytes are distinct from other oligodendrocytes, both in the healthy brain and in MS,” said Adams. “I aim to understand the molecular mechanisms that regulate generation of oligodendrocytes from neural stem cells, with the goal of identifying signals that could be targeted in MS patients to promote remyelination.”

Remyelination is very limited in MS patients and current therapies for MS have very little impact on promoting remyelination.

This study will take advantage of the state-of-the-art facilities for single-cell analysis, transcriptomics, microscopy, and animal research in Children’s Research Institute at Children’s National. Adams also added that her postdoctoral mentor, Vittorio Gallo, Ph.D., interim chief academic officer and interim director of the Children’s National Research Institute, and principal investigator for the DC-IDDRC, has renowned expertise in glial biology, animal models of MS and white matter injury.

“This research will be the first to directly compare neural stem cell-derived oligodendrocytes with other resident oligodendrocytes in MS brain samples,” said Adams. “The results of this study will provide critical insight into the role that neural stem cells play in repair of MS demyelinated lesions.”

Adams received her doctorate in molecular biology from the University of California, Los Angeles where she used pluripotent stem cells to study motor neuron development. She currently investigates signaling pathways that regulate neural stem and progenitor cell maintenance and differentiation in the developing postnatal and adult brain, with a focus on the Endothelin-1 pathway. She is interested in understanding how stem and progenitor cells respond to disease or injury, such as in Multiple Sclerosis, with the hope of identifying new therapeutic targets.

allopregnanolone molecule

Autism spectrum disorder risk linked to insufficient placental steroid

allopregnanolone molecule

A study led by Children’s National Hospital and presented during Neuroscience 2019 finds that loss of allopregnanolone, a key hormone supplied by the placenta, leads to long-term structural alterations of the cerebellum – a brain region essential for smooth motor coordination, balance and social cognition – and increases the risk of developing autism.

An experimental model study suggests that allopregnanolone, one of many hormones produced by the placenta during pregnancy, is so essential to normal fetal brain development that when provision of that hormone decreases – as occurs with premature birth – offspring are more likely to develop autism-like behaviors, a Children’s National Hospital research team reports at the Neuroscience 2019 annual meeting.

“To our knowledge, no other research team has studied how placental allopregnanolone (ALLO) contributes to brain development and long-term behaviors,” says Claire-Marie Vacher, Ph.D., lead author. “Our study finds that targeted loss of ALLO in the womb leads to long-term structural alterations of the cerebellum – a brain region that is essential for motor coordination, balance and social cognition ­– and increases the risk of developing autism,” Vacher says.

According to the Centers for Disease Control and Prevention, about 1 in 10 infants is born preterm, before 37 weeks gestation; and 1 in 59 children has autism spectrum disorder.

In addition to presenting the abstract, on Monday, Oct. 21, Anna Penn, M.D., Ph.D., the abstract’s senior author, will discuss the research with reporters during a Neuroscience 2019 news conference. This Children’s National abstract is among 14,000 abstracts submitted for the meeting, the world’s largest source of emerging news about brain science and health.

ALLO production by the placenta rises in the second trimester of pregnancy, and levels of the neurosteroid peak as fetuses approach full term.

To investigate what happens when ALLO supplies are disrupted, a research team led by Children’s National created a novel transgenic preclinical model in which they deleted a gene essential in ALLO synthesis. When production of ALLO in the placentas of these experimental models declines, offspring had permanent neurodevelopmental changes in a sex- and region-specific manner.

“From a structural perspective, the most pronounced cerebellar abnormalities appeared in the cerebellum’s white matter,” Vacher adds. “We found increased thickness of the myelin, a lipid-rich insulating layer that protects nerve fibers. From a behavioral perspective, male offspring whose ALLO supply was abruptly reduced exhibited increased repetitive behavior and sociability deficits – two hallmarks in humans of autism spectrum disorder.”

On a positive note, providing a single ALLO injection during pregnancy was enough to avert both the cerebellar abnormalities and the aberrant social behaviors.

The research team is now launching a new area of research focus they call “neuroplacentology” to better understand the role of placenta function on fetal and newborn brain development.

“Our team’s data provide exciting new evidence that underscores the importance of placental hormones on shaping and programming the developing fetal brain,” Vacher notes.

  • Neuroscience 2019 presentation
    Sunday, Oct. 20, 9:30 a.m. (CDT)
    “Preterm ASD risk linked to cerebellar white matter changes”
    Claire-Marie Vacher, lead author; Sonia Sebaoui, co-author; Helene Lacaille, co-author; Jackie Salzbank, co-author; Jiaqi O’Reilly, co-author; Diana Bakalar, co-author; Panagiotis Kratimenos, M.D., neonatologist and co-author; and Anna Penn, M.D., clinical neonatologist and developmental neuroscientist and senior author.
Vittorio Gallo

How the environment helps to shape the brain

Vittorio Gallo

“The strength, duration and timing of environmental experience influences plasticity in brain circuitry, which is made up of communication cables called axons that link neurons throughout the brain and are coated by myelin, a fatty substance that helps nerve impulses speed from place to place,” says Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National and senior study author.

Researchers have long known that babies of all kinds need to be exposed to rich, complex environments for optimal brain health and potential. Exposure to new sights, sounds and other sensory experiences appears to be critical for strengthening infants’ developing brains and encouraging smoothly running neural networks. Until recently, little was known about the biological mechanisms behind this phenomenon.

In a review article published online Aug. 22, 2017 in Trends in Neurosciences, Children’s National Health System researchers discuss the role of environmental stimuli on the development of myelin—the fatty insulation that surrounds the extensions that connect cells throughout the nervous system and make up a large part of the brain’s white matter. Positive influences, such as exposure to a large vocabulary and novel objects, can boost the growth of myelin. Conversely, negative influences, such as neglect and social isolation, can harm it, potentially altering the course of brain development.

“The strength, duration and timing of environmental experience influences plasticity in brain circuitry, which is made up of communication cables called axons that link neurons throughout the brain and are coated by myelin, a fatty substance that helps nerve impulses speed from place to place,” says Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National and senior study author. “As it responds to environmental stimuli, the brain continually shores up myelin’s integrity. Just as important, damaged myelin can leave gaps in the neural network which can lead to cognitive, motor and behavioral deficits.”

According to Gallo and study lead author Thomas A. Forbes, a pool of oligodendrocyte progenitor cells (OPCs) specialize in making myelin and do so from childhood into adulthood. The resulting oligodendrocyte cells (OLs) form an important working partnership with axons. From approximately 23 to 37 weeks’ gestation, OLs develop in the fetal brain and they continue to be generated after birth until adolescence.

“This dynamic feedback loop between myelin plasticity and neuronal excitability is crucial,” Forbes says. “It helps to strengthen motor and cognitive function and permits children and adults to learn new skills and to record new memories.”

In utero, genetics plays an outsized role in the initial structure of white matter, which is located in the subcortical region of the brain and takes its white color from myelin, the lipid and protein sheath that electrically insulates nerve cells. Defects in the microstructural organization of white matter are associated with many neurodevelopmental disorders. Once infants are born, environmental experiences also can begin to exert a meaningful role.

“The environment can be viewed as a noninvasive therapeutic approach that can be employed to bolster white matter health, either on its own or working in tandem with pharmacologic therapies,” Gallo adds. “The question is how to design the best environment for infants and children to grow and to achieve the highest cognitive function. An enriched environment not only involves the opportunity to move and participate in physical exercise and physical therapy; it is also an environment where there is novelty, new experiences and continuously active learning. It is equally important to minimize social stressors. It’s all about the balance.”

Among the potential interventions to boost brain power, independent of socioeconomic status:

  • Exposing children to new and different objects with an opportunity for physical activity and interaction with a number of playmates. This type of setting challenges the child to continuously adapt to his or her surroundings in a social, physical and experiential manner. In experimental models, enriched environments supported brain health by increasing the volume and length of myelinated fibers, the volume of myelin sheaths and by boosting total brain volume.
  • Exposure to music helps with cognition, hearing and motor skills for those who play an instrument, tapping multiple areas of the brain to work together collaboratively. Diffusion tensor imaging (DTI) reveals that professional pianists who began playing as children have improved white matter integrity and plasticity, Gallo and Forbes
  • At its heart, active learning requires interacting with and adapting to the environment. Generating new OLs influences learning new motor skills in the very young as well as the very old. And cognitive training and stimulation shapes and preserves white matter integrity in the aging.
  • DTI studies indicate that four weeks of integrative mind-body training alters myelination and improves white matter efficiency with especially pronounced changes in the area of the brain responsible for self-regulation, impulse control and emotion.
  • Voluntary exercise in experimental models is associated with OPCs differentiating into mature OLs. Imaging studies show a positive relationship between physical fitness, white matter health and the brain networks involved in memory.

Conversely, such negative influences as premature birth, poor nutrition, disease, neglect and social isolation can degrade myelin integrity, compromising the person’s ability to carry out basic motor skills and cognitive function. Usually, the pool of OPCs expands as the fetus is about to be born. But brain injury, lack of oxygen and restricted blood supply can delay maturation of certain brain cells and can cause abnormalities in white matter that diminish the brain’s capacity to synthesize myelin. Additional white matter insults can be caused by use of anesthesia and stress, among other variables.

The environmental influence has the potential to be “the Archimedes’ Lever to appropriating WM development among a limited range of only partially efficacious treatment options,” the authors conclude.

Vittorio Gallo

Vittorio Gallo named Chief Research Officer

Vittorio Gallo

As chief research officer, Vittorio Gallo, Ph.D., will be instrumental in developing and realizing Children’s Research Institute’s long-term strategic vision.

Children’s National Health System has appointed the longtime director of its Center for Neuroscience Research, Vittorio Gallo, Ph.D., as Chief Research Officer. Gallo’s appointment comes at a pivotal time for the institution’s research strategic plan, as significant growth and expansion will occur in the next few years. Gallo is a neuroscientist who studies white matter disorders, with particular focus on white matter growth and repair. He is also the Wolf-Pack Chair in Neuroscience at Children’s Research Institute, the academic arm of Children’s National.

As Chief Research Officer, Gallo will be instrumental in developing and realizing Children’s Research Institute’s long-term strategic vision, which includes building out the nearly 12-acre property once occupied by Walter Reed National Military Medical Center to serve as a regional innovation hub and to support Children’s scientists conducting world-class pediatric research in neuroscience, genetics, clinical and translational science, cancer and immunology. He succeeds Mendel Tuchman, M.D., who has had a long and distinguished career as Children’s Chief Research Officer for the past 12 years and who will remain for one year in an emeritus role, continuing federally funded research projects and mentoring junior researchers.

“I am tremendously pleased that Vittorio has agreed to become Chief Research Officer as of July 1, 2017, at such a pivotal time in Children’s history,” says Mark L. Batshaw, M.D., Physician-in-Chief and Chief Academic Officer at Children’s National. “Since Mendel announced plans to retire last summer, I spent a great deal of time talking to Children’s Research Institute investigators and leaders and also asking colleagues around the nation about the type of person and unique skill sets needed to serve as Mendel’s successor. With each conversation, it became increasingly clear that the most outstanding candidate for the Chief Research Officer position already works within Children’s walls,” Dr. Batshaw adds.

“I am deeply honored by being selected as Children’s next Chief Research Officer and am excited about being able to play a leadership role in defining the major areas of research that will be based at the Walter Reed space. The project represents an incredible opportunity to maintain the core nucleus of our research strengths – genetics, immunology, neurodevelopmental disorders and disabilities – and to expand into new, exciting areas of research. What’s more, we have an unprecedented opportunity to form new partnerships with peers in academia and private industry, and forge new community partnerships,” Gallo says. “I am already referring to this as Walter Reed ‘Now,’ so that we are not waiting for construction to begin to establish these important partnerships.”

Gallo’s research focus has been on white matter development and injury, myelin and glial cells – which are involved in the brain’s response to injury. His past and current focus is also on neural stem cells. His work in developmental neuroscience has been seminal in deepening understanding of cerebral palsy and multiple sclerosis. He came to Children’s National from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) intramural program. His intimate knowledge of the workings of the National Institutes of Health (NIH) has helped him to establish meaningful collaborations between both institutions. During his tenure, he has transformed the Center for Neuroscience Research into one of the nation’s premier programs. The Center is home to the prestigious NIH/NICHD-funded District of Columbia Intellectual and Developmental Disabilities Research Center, which Gallo directs.

Children’s research scientists working under the auspices of Children’s Research Institute conduct and promote highly collaborative and multidisciplinary research within the hospital that aims to better understand, treat and, ultimately, prevent pediatric disease. As Chief Research Officer, Gallo will continue to establish and enhance collaborations between research and clinical programs. Such cross-cutting projects will be essential in defining new mechanisms that underlie pediatric disease. “We know, for instance, that various mechanisms contribute to many genetic and neurological pediatric diseases, and that co-morbidities add another layer of complexity. Tapping expertise across disciplines has the potential to unravel current mysteries, as well as to better characterize unknown and rare diseases,” he says.

“Children’s National is among the nation’s top seven pediatric hospitals in NIH research funding, and the extraordinary innovations that have been produced by our clinicians and scientists have been put into practice here and in hospitals around the world,” Dr. Batshaw adds. “Children’s leadership aspires to nudge the organization higher, to rank among the nation’s top five pediatric hospitals in NIH research funding.”

Gallo says the opportunity for Children’s research to expand beyond the existing buildings and the concurrent expansion into new areas of research will trigger more hiring. “We plan to grow our research enterprise through strategic hires and by attracting even more visiting investigators from around the world. By expanding our community of investigators, we aim to strengthen our status as one of the nation’s leading pediatric hospitals,” he says.