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illustration of brain showing cerebellum

Focusing on the “little brain” to rescue cognition

illustration of brain showing cerebellum

Research faculty at Children’s National in Washington, D.C., with colleagues recently published a review article in Nature Reviews Neuroscience that covers the latest research about how abnormal development of the cerebellum leads to a variety of neurodevelopmental disorders.

Cerebellum translates as “little brain” in Latin. This piece of anatomy – that appears almost separate from the rest of the brain, tucked under the two cerebral hemispheres – long has been known to play a pivotal role in voluntary motor functions, such as walking or reaching for objects, as well as involuntary ones, such as maintaining posture.

But more recently, says Aaron Sathyanesan, Ph.D., a postdoctoral research fellow at the Children’s Research Institute, the research arm of Children’s National  in Washington, D.C., researchers have discovered that the cerebellum is also critically important for a variety of non-motor functions, including cognition and emotion.

Sathyanesan, who studies this brain region in the laboratory of Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National and scientific director of the Children’s Research Institute, recently published a review article with colleagues in Nature Reviews Neuroscience covering the latest research about how altered development of the cerebellum contributes to a variety of neurodevelopmental disorders.

These disorders, he explains, are marked by problems in the nervous system that arise while it’s maturing, leading to effects on emotion, learning ability, self-control, or memory, or any combination of these. They include diagnoses as diverse as intellectual disability, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder and Down syndrome.

“One reason why the cerebellum might be critically involved in each of these disorders,” Sathyanesan says, “is because its developmental trajectory takes so long.”

Unlike other brain structures, which have relatively short windows of development spanning weeks or months, the principal cells of the cerebellum – known as Purkinje cells – start to differentiate from stem cell precursors at the beginning of the seventh gestational week, with new cells continuing to appear until babies are nearly one year old.  In contrast, cells in the neocortex, a part of the brain involved in higher-order brain functions such as cognition, sensory perception and language is mostly finished forming while fetuses are still gestating in the womb.

This long window for maturation allows the cerebellum to make connections with other regions throughout the brain, such as extensive connections with the cerebral cortex, the outer layer of the cerebrum that plays a key role in perception, attention, awareness, thought, memory, language and consciousness. It also allows ample time for things to go wrong.

“Together,” Sathyanesan says, “these two characteristics are at the root of the cerebellum’s involvement in a host of neurodevelopmental disorders.”

For example, the review article notes, researchers have discovered both structural and functional abnormalities in the cerebellums of patients with ASD. Functional magnetic resonance imaging (MRI), an imaging technique that measures activity in different parts of the brain, suggests that significant differences exist between connectivity between the cerebellum and cortex in people with ASD compared with neurotypical individuals. Differences in cerebellar connectivity are also evident in resting-state functional connectivity MRI, an imaging technique that measures brain activity in subjects when they are not performing a specific task. Some of these differences appear to involve patterns of overconnectivity to different brain regions, explains Sathyanesan; other differences suggest that the cerebellums of patients with ASD don’t have enough connections to other brain regions.

These findings could clarify research from Children’s National and elsewhere that has shown that babies born prematurely often sustain cerebellar injuries due to multiple hits, including a lack of oxygen supplied by infants’ immature lungs, he adds. Besides having a sibling with ASD, premature birth is the most prevalent risk factor for an ASD diagnosis.

The review also notes that researchers have discovered structural changes in the cerebellums of patients with Down syndrome, who tend to have smaller cerebellar volumes than neurotypical individuals. Experimental models of this trisomy recapitulate this difference, along with abnormal connectivity to the cerebral cortex and other brain regions.

Although the cerebellum is a pivotal contributor toward these conditions, Sathyanesan says, learning more about this brain region helps make it an important target for treating these neurodevelopmental disorders. For example, he says, researchers are investigating whether problems with the cerebellum and abnormal connectivity could be lessened through a non-invasive form of brain stimulation called transcranial direct current stimulation or an invasive one known as deep brain stimulation. Similarly, a variety of existing pharmaceuticals or new ones in development could modify the cerebellum’s biochemistry and, consequently, its function.

“If we can rescue the cerebellum’s normal activity in these disorders, we may be able to alleviate the problems with cognition that pervade them all,” he says.

In addition to Sathyanesan and Senior Author Gallo, Children’s National study co-authors include Joseph Scafidi, D.O., neonatal neurologist; Joy Zhou and Roy V. Sillitoe, Baylor College of Medicine; and Detlef H. Heck, of University of Tennessee Health Science Center.

Financial support for research described in this post was provided by the National Institute of Neurological Disorders and Stroke under grant numbers 5R01NS099461, R01NS089664, R01NS100874, R01NS105138 and R37NS109478; the Hamill Foundation; the Baylor College of Medicine Intellectual and Developmental Disabilities Research Center under grant number U54HD083092; the University of Tennessee Health Science Center (UTHSC) Neuroscience Institute; the UTHSC Cornet Award; the National Institute of Mental Health under grant number R01MH112143; and the District of Columbia Intellectual and Developmental Disabilities Research Center under grant number U54 HD090257.

sketch of muscle cells

Losing muscle to fat: misdirected fate of a multipotent stem cell drives LGMD2B

Fibro/adipogenic precursors (FAPs) control the onset and severity of disease in limb-girdle muscular dystrophy type 2 (LGMD2B)

Fibro/adipogenic precursors (FAPs) control the onset and severity of disease in limb-girdle muscular dystrophy type 2 (LGMD2B). a) Healthy and/or pre-symptomatic LGMD2B muscle contains resident FAPs. b) After myofiber injury, inflammatory cells invade and trigger FAP proliferation. c) In symptomatic LGMD2B muscle, there is a gradual accumulation of extracellular AnxA2, which prolongs the pro-inflammatory environment, causing excessive FAP proliferation. d) Blocking aberrant signaling due to AnxA2 buildup blocks FAP accumulation and thus preventing adipogenic loss of dysferlinopathic muscle. Credit: “Fibroadipogenic progenitors are responsible for muscle loss in limb girdle muscular dystrophy 2B.” Published online June 3, 2019, in Nature Communications. Marshall W. Hogarth, Aurelia Defour, Christopher Lazarski, Eduard Gallardo, Jordi Diaz Manera, Terence A. Partridge, Kanneboyina Nagaraju and Jyoti K. Jaiswal. https://rdcu.be/bFu9U.

Research led by faculty at Children’s National published online June 3, 2019, in Nature Communications shows that the sudden appearance of symptoms in limb-girdle muscular dystrophy type 2 (LGMD2B) is a result of impaired communication between different cell types that facilitate repair in healthy muscle. Of particular interest are the fibro/adipogenic precursors (FAPs), cells that typically play a helpful role in regenerating muscle after injury by removing debris and enhancing the fusion of muscle cells into new myofibers.

LGMD2B is caused by mutations in the DYSF gene that impair the function of dysferlin, a protein essential for repairing injured muscle fibers. Symptoms, like difficulty climbing or running, do not appear in patients until young adulthood. This late onset has long puzzled researchers, as the cellular consequences of dysferlin’s absence are present from birth and continue through development, but do not impact patients until later in life.

The study found that in the absence of dysferlin, muscle gradually increases the expression of the protein Annexin A2 which, like dysferlin, facilitates repair of injured muscle fiber. However, increasing Annexin A2 accumulates outside the muscle fiber and drives an increase in FAPs within the muscle as well as encourages these FAPs to differentiate into adipocytes, forming fatty deposits. Shutting down Annexin A2 or blocking the adipocyte fate of FAPs using an off-the-shelf medicine arrests the fatty replacement of dysferlinopathic muscle.

“We propose a feed-forward loop in which repeated myofiber injury triggers chronic inflammation which, over time, creates an environment that promotes FAPs to accumulate and differentiate into fat. This, in turn, contributes to more myofiber damage,” says Jyoti K. Jaiswal, MSc, Ph.D., a principal investigator in the Center for Genetic Medicine Research at Children’s National and the study’s senior author.

“Adipogenic accumulation becomes the nucleating event that results in an abrupt decline in muscle function in patients. This new view of LGMD2B disease opens previously unrealized avenues to intervene,” adds Marshall Hogarth, Ph.D., the study’s lead author.

Joyti Jaiswal

“We propose a feed-forward loop in which repeated myofiber injury triggers chronic inflammation which, over time, creates an environment that promotes FAPs to accumulate and differentiate into fat. This, in turn, contributes to more myofiber damage,” says Jyoti K. Jaiswal, MSc, Ph.D.

A research team led by Jaiswal collaborated with Eduard Gallardo and Jordi Diaz Manera, of Hospital de la Santa Creu in Barcelona, Spain, to examine muscle biopsies from people with LGMD2B who had mild to severe symptoms. They found that adipogenic deposits originate in the extracellular matrix space between muscle fibers, with the degree of accumulation tied to disease severity. They found a similar progressive increase in lipid accumulation between myofibers predicted disease severity in dysferlin-deficient experimental models. What’s more, this process can be accelerated by muscle injury, triggering increased adipogenic replacement in areas that otherwise would be occupied by muscle cells.

“Accumulation and adipogenic differentiation of FAPs is responsible for the decline in function for dysferlinopathic muscle. Reversing this could provide a therapy for LGMD2B, a devastating disease with no effective treatment,” predicts Jaiswal as the team continues research in this field.

Promising off-the-shelf drugs include batimastat, an anti-cancer drug that inhibits the extracellular matrix enzyme matrix metalloproteinase. This drug reduces FAP adipogenesis in vitro and lessens injury-triggered lipid formation in vivo. In experimental models, batimastat also increases muscle function.

In addition to Jaiswal, Hogarth, Gallardo and Diaz Manera, other study co-authors include Aurelia Defour, Christopher Lazarski, Terence A. Partridge and Kanneboyina Nagaraju, all of Children’s National.

Financial support for research described in this post was provided by the Muscular Dystrophy Association under awards MDA477331 and MDA277389, the National Institute of Arthritis and Musculoskeletal and Skin Diseases under award R01AR055686 and the National Institutes of Health under awards K26OD011171, R24HD050846 and P50AR060836.

Billie Lou Short and Kurt Newman at Research and Education Week

Research and Education Week honors innovative science

Billie Lou Short and Kurt Newman at Research and Education Week

Billie Lou Short, M.D., received the Ninth Annual Mentorship Award in Clinical Science.

People joke that Billie Lou Short, M.D., chief of Children’s Division of Neonatology, invented extracorporeal membrane oxygenation, known as ECMO for short. While Dr. Short did not invent ECMO, under her leadership Children’s National was the first pediatric hospital to use it. And over decades Children’s staff have perfected its use to save the lives of tiny, vulnerable newborns by temporarily taking over for their struggling hearts and lungs. For two consecutive years, Children’s neonatal intensive care unit has been named the nation’s No. 1 for newborns by U.S. News & World Report. “Despite all of these accomplishments, Dr. Short’s best legacy is what she has done as a mentor to countless trainees, nurses and faculty she’s touched during their careers. She touches every type of clinical staff member who has come through our neonatal intensive care unit,” says An Massaro, M.D., director of residency research.

For these achievements, Dr. Short received the Ninth Annual Mentorship Award in Clinical Science.

Anna Penn, M.D., Ph.D., has provided new insights into the central role that the placental hormone allopregnanolone plays in orderly fetal brain development, and her research team has created novel experimental models that mimic some of the brain injuries often seen in very preterm babies – an essential step that informs future neuroprotective strategies. Dr. Penn, a clinical neonatologist and developmental neuroscientist, “has been a primary adviser for 40 mentees throughout their careers and embodies Children’s core values of Compassion, Commitment and Connection,” says Claire-Marie Vacher, Ph.D.

For these achievements, Dr. Penn was selected to receive the Ninth Annual Mentorship Award in Basic and Translational Science.

The mentorship awards for Drs. Short and Penn were among dozens of honors given in conjunction with “Frontiers in Innovation,” the Ninth Annual Research and Education Week (REW) at Children’s National. In addition to seven keynote lectures, more than 350 posters were submitted from researchers – from high-school students to full-time faculty – about basic and translational science, clinical research, community-based research, education, training and quality improvement; five poster presenters were showcased via Facebook Live events hosted by Children’s Hospital Foundation.

Two faculty members won twice: Vicki Freedenberg, Ph.D., APRN, for research about mindfulness-based stress reduction and Adeline (Wei Li) Koay, MBBS, MSc, for research related to HIV. So many women at every stage of their research careers took to the stage to accept honors that Naomi L.C. Luban, M.D., Vice Chair of Academic Affairs, quipped that “this day is power to women.”

Here are the 2019 REW award winners:

2019 Elda Y. Arce Teaching Scholars Award
Barbara Jantausch, M.D.
Lowell Frank, M.D.

Suzanne Feetham, Ph.D., FAA, Nursing Research Support Award
Vicki Freedenberg, Ph.D., APRN, for “Psychosocial and biological effects of mindfulness-based stress reduction intervention in adolescents with CHD/CIEDs: a randomized control trial”
Renee’ Roberts Turner for “Peak and nadir experiences of mid-level nurse leaders”

2019-2020 Global Health Initiative Exploration in Global Health Awards
Nathalie Quion, M.D., for “Latino youth and families need assessment,” conducted in Washington
Sonia Voleti for “Handheld ultrasound machine task shifting,” conducted in Micronesia
Tania Ahluwalia, M.D., for “Simulation curriculum for emergency medicine,” conducted in India
Yvonne Yui for “Designated resuscitation teams in NICUs,” conducted in Ghana
Xiaoyan Song, Ph.D., MBBS, MSc, “Prevention of hospital-onset infections in PICUs,” conducted in China

Ninth Annual Research and Education Week Poster Session Awards

Basic and Translational Science
Faculty:
Adeline (Wei Li) Koay, MBBS, MSc, for “Differences in the gut microbiome of HIV-infected versus HIV-exposed, uninfected infants”
Faculty: Hayk Barseghyan, Ph.D., for “Composite de novo Armenian human genome assembly and haplotyping via optical mapping and ultra-long read sequencing”
Staff: Damon K. McCullough, BS, for “Brain slicer: 3D-printed tissue processing tool for pediatric neuroscience research”
Staff: Antonio R. Porras, Ph.D., for “Integrated deep-learning method for genetic syndrome screening using facial photographs”
Post docs/fellows/residents: Lung Lau, M.D., for “A novel, sprayable and bio-absorbable sealant for wound dressings”
Post docs/fellows/residents:
Kelsey F. Sugrue, Ph.D., for “HECTD1 is required for growth of the myocardium secondary to placental insufficiency”
Graduate students:
Erin R. Bonner, BA, for “Comprehensive mutation profiling of pediatric diffuse midline gliomas using liquid biopsy”
High school/undergraduate students: Ali Sarhan for “Parental somato-gonadal mosaic genetic variants are a source of recurrent risk for de novo disorders and parental health concerns: a systematic review of the literature and meta-analysis”

Clinical Research
Faculty:
Amy Hont, M.D., for “Ex vivo expanded multi-tumor antigen specific T-cells for the treatment of solid tumors”
Faculty: Lauren McLaughlin, M.D., for “EBV/LMP-specific T-cells maintain remissions of T- and B-cell EBV lymphomas after allogeneic bone marrow transplantation”

Staff: Iman A. Abdikarim, BA, for “Timing of allergenic food introduction among African American and Caucasian children with food allergy in the FORWARD study”
Staff: Gelina M. Sani, BS, for “Quantifying hematopoietic stem cells towards in utero gene therapy for treatment of sickle cell disease in fetal cord blood”
Post docs/fellows/residents: Amy H. Jones, M.D., for “To trach or not trach: exploration of parental conflict, regret and impacts on quality of life in tracheostomy decision-making”
Graduate students: Alyssa Dewyer, BS, for “Telemedicine support of cardiac care in Northern Uganda: leveraging hand-held echocardiography and task-shifting”
Graduate students: Natalie Pudalov, BA, “Cortical thickness asymmetries in MRI-abnormal pediatric epilepsy patients: a potential metric for surgery outcome”
High school/undergraduate students:
Kia Yoshinaga for “Time to rhythm detection during pediatric cardiac arrest in a pediatric emergency department”

Community-Based Research
Faculty:
Adeline (Wei Li) Koay, MBBS, MSc, for “Recent trends in the prevention of mother-to-child transmission (PMTCT) of HIV in the Washington, D.C., metropolitan area”
Staff: Gia M. Badolato, MPH, for “STI screening in an urban ED based on chief complaint”
Post docs/fellows/residents:
Christina P. Ho, M.D., for “Pediatric urinary tract infection resistance patterns in the Washington, D.C., metropolitan area”
Graduate students:
Noushine Sadeghi, BS, “Racial/ethnic disparities in receipt of sexual health services among adolescent females”

Education, Training and Program Development
Faculty:
Cara Lichtenstein, M.D., MPH, for “Using a community bus trip to increase knowledge of health disparities”
Staff:
Iana Y. Clarence, MPH, for “TEACHing residents to address child poverty: an innovative multimodal curriculum”
Post docs/fellows/residents:
Johanna Kaufman, M.D., for “Inpatient consultation in pediatrics: a learning tool to improve communication”
High school/undergraduate students:
Brett E. Pearson for “Analysis of unanticipated problems in CNMC human subjects research studies and implications for process improvement”

Quality and Performance Improvement
Faculty:
Vicki Freedenberg, Ph.D., APRN, for “Implementing a mindfulness-based stress reduction curriculum in a congenital heart disease program”
Staff:
Caleb Griffith, MPH, for “Assessing the sustainability of point-of-care HIV screening of adolescents in pediatric emergency departments”
Post docs/fellows/residents:
Rebecca S. Zee, M.D., Ph.D., for “Implementation of the Accelerated Care of Torsion (ACT) pathway: a quality improvement initiative for testicular torsion”
Graduate students:
Alysia Wiener, BS, for “Latency period in image-guided needle bone biopsy in children: a single center experience”

View images from the REW2019 award ceremony.

dystrophin protein

Experimental drug shows promise for slowing cardiac disease and inflammation

dystrophin protein

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene, which provides instructions for making dystrophin, a protein found mostly in skeletal, respiratory and heart muscles.

Vamorolone, an experimental medicine under development, appears to combine the beneficial effects of prednisone and eplerenone – standard treatments for Duchenne muscular dystrophy (DMD) – in the heart and muscles, while also showing improved safety in experimental models. The drug does so by simultaneously targeting two nuclear receptors important in regulating inflammation and cardiomyopathy, indicates a small study published online Feb. 11, 2019, in Life Science Alliance.

DMD is a progressive X-linked disease that occurs mostly in males. It is characterized by muscle weakness that worsens over time, and most kids with DMD will use wheelchairs by the time they’re teenagers. DMD is caused by mutations in the DMD gene, which provides instructions for making dystrophin, a protein found mostly in skeletal, respiratory and heart muscles.

Cardiomyopathy, an umbrella term for diseases that weaken the heart, is a leading cause of death for young adults with DMD, causing up to 50 percent of deaths in patients who lack dystrophin. A collaborative research team co-led by Christopher R. Heier, Ph.D., and Christopher F. Spurney, M.D., of Children’s National Health System, is investigating cardiomyopathy in DMD. They find genetic dystrophin loss provides “a second hit” for a specific pathway that worsens cardiomyopathy in experimental models of DMD.

“Some drugs can interact with both the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) since these two drug targets evolved from a common ancestor. However, we find these two drug targets can play distinctly different roles in heart and skeletal muscle. The GR regulates muscle inflammation, while the MR plays a key role in heart health,” says Heier, an assistant professor at Children’s National and lead study author. “In our study, the experimental drug vamorolone safely targets both the GR to treat chronic inflammation and the MR to treat the heart.”

After gauging the efficacy of various treatments in test tubes, the study team looked at whether any could mitigate negative impacts of the MR on heart health. Wild type and mdx experimental models were implanted with pumps that activated the MR. These models also received a daily oral MR antagonist (or inhibitor) drug, and either eplerenone, spironolactone or vamorolone. Of note:

  • MR activation increased kidney size and caused elevated blood pressure (hypertension).
  • Treatment with vamorolone maintained normal kidney size and prevented hypertension.
  • MR activation increased mdx heart mass and fibrosis. Vamorolone mitigated these changes.
  • MR activation decreased mdx heart function, while vamorolone prevented declines in function.
  • Daily prednisone caused negative MR- and GR-mediated side effects, such as hyperinsulinemia, whereas vamorolone safely improved heart function without these side effects.

“These findings have the potential to help current and future patients,” Heier says. “Clinicians already prescribe several of these drugs. Our new data support the use of MR antagonists such as eplerenone in protecting DMD hearts, particularly if patients take prednisone. The experimental drug vamorolone is currently in Phase IIb clinical trials and is particularly exciting for its unique potential to simultaneously treat chronic inflammation and heart pathology with improved safety.”

In addition to Heier and senior author Spurney, study co-authors include Qing Yu, Alyson A. Fiorillo, Christopher B. Tully, Asya Tucker and Davi A. Mazala, all of Children’s National; Kitipong Uaesoontrachoon and Sadish Srinivassane, AGADA Biosciences Inc.; and Jesse M. Damsker, Eric P. Hoffman and Kanneboyina Nagaraju, ReveraGen BioPharma.

Financial support for research described in this report was provided by Action Duchenne; the Clark Charitable Foundation; the Department of Defense under award W81XWH-17-1-047; the Foundation to Eradicate Duchenne; the Intellectual and Developmental Disabilities Research Center under award U54HD090257 (through the National Institutes of Health’s (NIH) Eunice Kennedy Shriver National Institute of Child Health and Human Development); and the NIH under awards K99HL130035, R00HL130035, L40AR068727 and T32AR056993.

Financial disclosure:  Co-authors employed by ReveraGen BioPharma were involved in creating this news release.