Dr. Nikolaos Ziogas receives top finalist award at National Neurotrauma Symposium 2017

September 12th, 2017

Nikolaos Ziogas M.D., postdoctoral fellow at the Koliatsos Laboratory, was recognized as a top finalist at the 35th National Neurotrauma Society’s Annual Symposium, Snowbird, Utah for his work “Primary traumatic axonopathy after impact acceleration: characterization of pathology with 3D high-resolution methods”. The combination of brain clearing with 2-photon microscopy to 3D reconstruct the mouse brain stem, allowed for the first time a new level of qualitative and quantitative understanding of axonal injury, including its progressive nature and its proclivity for sites of geometrical complexity and intertwinement of various axon tracts after traumatic brain injury.

Dr. Nikolaos Ziogas Wins First Place; Post-Doctoral Fellow Poster Awards at National Capital Area TBI Research Symposium 2017

September 12th, 2017

Nikolaos Ziogas M.D., postdoctoral fellow at the Koliatsos Laboratory, was the winner of the “Post-Doctoral Fellow Poster Awards” at the annual National Capital Area Traumatic Brain Injury Symposium held at the National Institutes of Health, Bethesda, DC for the second consecutive year for his work “Diffuse axonal injury, blood brain barrier disruption and neuroinflammation after a single concussion with impact acceleration in the mouse”. A novel brain clearing technique, CLARITY, has been developed as a neuropathological tool for this work in order to visualize the whole mouse brain stem after concussion in single axon resolution, revealing widespread diffuse axonal injury.

Mouse study on serotonin in Alzheimer’s Disease by Alena Savonenko expanded to human patients

August 19th, 2017

Brain Scan Study Adds to Evidence That Lower Brain Serotonin Levels Are Linked to Dementia

In a study looking at brain scans of people with mild loss of thought and memory ability, Johns Hopkins researchers report evidence of lower levels of the serotonin transporter—a natural brain chemical that regulates mood, sleep, and appetite. Their results, the researchers say, suggest that lower serotonin transporters may be drivers of the disease rather than a byproduct.

A report on the study, published in Neurobiology of Disease, also suggests that finding ways to prevent the loss of serotonin or introducing a substitute neurotransmitter could slow or stop the progression of Alzheimer’s disease and perhaps other dementias.

“Now that we have more evidence that serotonin is a chemical that appears affected early in cognitive decline, we suspect that increasing serotonin function in the brain could prevent memory loss from getting worse and slow disease progression,” says Gwenn Smith, professor of psychiatry and behavioral sciences and director of geriatric psychiatry and neuropsychiatry at the School of Medicine.

Smith notes that researchers have tried with limited success to treat Alzheimer’s disease and cognitive impairment with antidepressants such as SSRIs, which bind to the serotonin transporters and block the brain’s “reuptake” of the chemical. But because these transporters are at much lower levels in people with Alzheimer’s, she speculates that the drugs can’t serve their purpose without their target.

The Johns Hopkins research team paired 28 participants with mild cognitive impairment, which may be an early harbinger of Alzheimer’s disease or other forms of dementia, with 28 healthy matched controls. People with mild cognitive impairment were defined as those who have a slight decline in cognition, mainly in memory in terms of remembering sequences or organization, and who score lower on tests such as the California Verbal Learning Test, which requires participants to recall a list of related words, such as a shopping list. According to Smith, the inability to do this test accurately reflects changes in memory and cognitive impairment indicative of Alzheimer’s disease.

Participants were an average age of 66 and about 45 percent were women.

Each participant underwent an MRI and PET scan to measure brain structures and levels of the serotonin transporter. During the PET scans, participants were given a chemical—similar in structure to an antidepressant but not a high enough dose to have a pharmacological effect—labeled with a radioactive carbon. The chemical binds to the serotonin transporter and the PET scanner detects the radioactivity.

The researchers found that people with mild cognitive impairment had up to 38 percent less of the serotonin transporter detected in their brains compared to each of their age-matched healthy controls. And not a single person with mild cognitive impairment had higher levels of the serotonin transporter compared to their healthy control.

Each participant also underwent learning and memory tests. In the California Verbal Learning Test, on a scale of 0 to 80, with 80 reflecting the best memory, the healthy participants had an average score of 55.8, whereas those with mild cognitive impairment scored an average of 40.5. During a Brief Visuospatial Memory Test, participants were shown a series of shapes to remember and draw later. From a scale of 0 to 36, with 36 being the top score, healthy people scored an average of 20.0 and those with mild cognitive problems scored an average of 12.6.

The idea for Smith’s study was inspired by the work of co-author Alena Savonenko, an associate professor of pathology who showed that loss of serotonin neurons was associated with more protein clumps, or amyloid, in mouse brains. Savonenko and Smith say their group will investigate whether PET imaging of serotonin could be a marker to detect progression of disease, whether alone or in conjunction with scans that detect amyloid, which has also been shown to accumulate in the brains of those with Alzheimer’s disease.
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Experimental “Enhancer” Drug May Boost Conventional Therapies for Deadly Pediatric Brain Cancers

July 14th, 2017

Laboratory studies suggest that an experimental drug already in early clinical trials for a variety of adult cancers might enhance radiation and chemotherapy for two childhood brain cancers that currently are virtually always fatal.

In a report on two studies conducted by Johns Hopkins Kimmel Cancer Center researchers, the drug, known as TAK228, suppressed the growth of human cancer cells cultured in the laboratory and significantly extended the lives of mice implanted with cells from the two cancers, diffuse intrinsic pontine glioma (DIPG) and atypical teratoid/rhabdoid tumors (AT/RTs).

DIPG — a cancer in the brainstem affecting about 3,000 children worldwide each year — is universally fatal even with currently available treatments including surgery, chemotherapy and radiation. AT/RTs, the most common brain cancer in infants, have a similarly poor prognosis, with most patients surviving between six and 11 months after diagnosis.

Hoping to help beat these odds, Johns Hopkins researchers and their colleagues, led by Eric H. Raabe, M.D., Ph.D., assistant professor of oncology and instructor of pathology at the Johns Hopkins Kimmel Cancer Center, focused their attention on TAK228. Previous research showed the drug (also known as MLN0128) can cross the blood-brain barrier and reduces the production of a protein called mTOR, which appears to sustain cancer by combining with other proteins to signal the cells to grow, invade tissues and survive therapy. Both pediatric cancer types typically have genetic alterations that lead to increases in mTOR activity, thus Raabe and his team’s hypothesis that TAK228 could be an effective treatment for these cancers.

In one set of experiments, Raabe and his colleagues applied the drug to cells of each cancer type isolated from human patients. Results showed that TAK228 reduced proliferation of DIPG cells cancer cells by about 30 percent compared with control (untreated) cells and killed about 6 percent of the cells.

However, when combined with radiation — currently the most effective treatment for extending life in children with DIPG — nearly double the number of cells were killed compared with radiation alone, suggesting that TAK228 might sensitize cells to make radiation more effective, Raabe says.

When the team tested TAK228 on AT/RT cells, they found similar reductions in tumor cell proliferation and increases in cancer cell death. Further, when they gave a combination of TAK228 and cisplatin, a chemotherapy commonly used to treat AT/RTs, to mice bearing implanted human AT/RT tumors, the mice receiving the combined treatment lived approximately 30 days longer than those that received either treatment alone. Some 40 percent of the combination-treated mice were long-term survivors (living more than 60 days after tumor injection), while none of the mice treated with either chemotherapy or TAK228 alone lived longer than 25 days.

A report of the experiments in DIPG is published online April 25 in Cancer Letters, and the AT/RT report is published June 3 in Neuro-Oncology. Together, Raabe says, these results suggest that TAK228 could hold promise for human patients.

“Both of these papers set the stage for clinical trials for TAK228,” he says. “Our experiments show that TAK228 can make traditional chemotherapy and radiation more effective, which may offer hope to patients for whom current therapy doesn’t work very well.”

The team is currently investigating further how the drug works with radiation and chemotherapy, and if other drugs might be able to heighten this synergistic effect.

Other Johns Hopkins researchers who participated in the DIPG study include Hiroaki Miyahara, Manabu Natsumeda, Jeffrey A. Rubens, Isabella C. Taylor, Harpreet Kaur, Laura Asnaghi and Charles G. Eberhart. Other Johns Hopkins researchers who participated in the AT/RT study include Jeffrey A. Rubens, Sabrina Z. Wang, Antoinette Price, Melanie F. Weingart and Charles G. Eberhart.

The DIPG research was funded by the Cure Starts Now Foundation, the Giant Food Pediatric Cancer Research Fund, the National Institutes of Health’s National Cancer Institute (P30 CA006973, T32CA60441), Smashing Walnuts/Piedmont Community, the Goldwin Foundation and the St. Baldrick’s Foundation.

Funding for the AT/RT research was provided by Alex’s Lemonade Stand, the Giant Food Pediatric Cancer Research Fund, the National Institutes of Health’s National Cancer Institute (P30 CA006973, T32CA60441) and the St. Baldrick’s Foundation.

A New Therapeutic target and Potential Biomarkers Identified in Alzheimer’s Disease

June 19th, 2017

Significant progress has been made over the past two decades on the pathogenesis of individual neurodegenerative diseases, including Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, different neurodegenerative syndromes have been mainly studied mechanistically in isolation. There has been a lack of concerted effort to ascertain whether and how these pathogenic processes may be linked to one another. In the most recent issue of journal Acta Neuropathologica, Dr. Mingkuan Sun, William Bell and Katherine LaClair, co-first authored a report about cryptic exon incorporation in Alzheimer’s disease cases exhibiting TDP-43 pathology. This is the first evidence on how loss of TDP-43 function from neurons, a common shared feature with ALS and FTD, could contribute to pathogenesis of AD.

It has been known for years that other factors besides Aβ and tau also contribute to neurodegeneration and cognitive failure in AD. The most convincing evidence is that 20-40% of cognitively normal older individuals have levels of Aβ and tau pathology that are indistinguishable from patients with severe clinical symptoms of AD. Recent work showed that non-canonical pathologies occur in up to 75% of AD cases, including TDP-43 proteinopathy, α-synuclein “Lewy bodies”, and tau “Pick bodies” that are associated with neurodegeneration in separately classified diseases. TDP-43 proteinopathy is characterized by cytoplasmic aggregation of the transactivation response element DNA-binding protein 43 (TDP-43) accompanied by its nuclear clearance, and was first identified in another neurodegenerative disease spectrum, ALS-FTD. Identified as an essential gene, TDP-43 is also required for aspects of neuronal physiology in mice, fruit flies and zebrafish. Notably, TDP-43 proteinopathy is one of the most common non-canonical pathologies observed in AD cases and is strongly associated with worsened neurodegeneration and cognition, suggesting a convergent mechanism of neurodegeneration with ALS and FTD.

In their paper, Sun et al. found that cryptic exon incorporation occurred in all AD cases exhibiting TDP-43 pathology. Furthermore, incorporation of cryptic exons was observed in the hippocampus when TDP-43 inclusions was restricted only to the amygdala, the earliest stage of TDP-43 progression. Most importantly, cryptic exon incorporation could be detected in AD brains lacking TDP- 43 inclusions, but exhibiting nuclear clearance of TDP-43. These data support the notion that the functional consequence of nuclear depletion of TDP-43, as determined by cryptic exon incorporation, likely occurs as an early event of TDP-43 proteinopathy and may have greater contribution to the pathogenesis of AD than currently appreciated. This study has opened new direction in AD research as early detection and effective repression of cryptic exons in AD patients may offer important diagnostic and therapeutic implications for this devastating illness of the elderly.

Co-authors were Jonathan Ling, Heather Han, Yusuke Kageyama, Olga Pletnikova, and Juan Troncoso of Johns Hopkins Brain Resource Center.  The work was supported in part by the Johns Hopkins Neuropathology Pelda fund and the NIH Grant to Dr. Philip Wong; McKnight Award for Memory and Cognitive Disorder and the Johns Hopkins Alzheimer’s Disease Research Center pilot grant to Dr. Liam Chen. 

Presentations at the 93rd Annual Meeting of the American Association of Neuropathologists.

June 10th, 2017

The 93rd Annual Meeting of the American Association of Neuropathologists was held June 8–11, 2017 in Garden Grove, CA. Neuropathology faculty members Liam Chen and Charles Eberhart, as well as a second year fellow, Heather Ames, all had abstracts selected for platform presentations. An incoming AP/NP resident, James Nix, also gave a platform talk, and second year fellow Andrew Guajardo presented a case at the diagnostic slide session. Many posters from incoming, current and recently departed trainees were also featured. The titles and authors of the platform presentations are shown below.
– Cryptic exon splicing repression by TDP-43 represents its major function compromised in Alzheimer’s disease and ALS/FTD. Liam Chen, Mingkuan Sun, Robert Bell, Olga Pletnikova, Juan Troncoso, Philip Wong
– Identifying corneal infections in formalin fixed specimens using next generation sequencing. Charles Eberhart, Zhigang Li, Florian Breitwies, Jennifer Lu, Albert Jun, Steven Salzberg
– Insulinoma-associated 1 (INSM1) is a novel nuclear marker of immature neuronal central nervous system neoplasms. Heather Ames, Lisa Rooper, Charles Eberhart, Fausto Rodriguez
– Neuropathology In Social Media. James Nix, Jerad Gardner, Murat Gokden, Brian Moore, Fausto Rodriguez, Maria Martinez-Lage, Felipe Costa, Douglas Anthony

Brain Cancer Surpasses Leukemia as #1 Pediatric Cancer Killer

September 19th, 2016


Author: Andrew Black


New data from the CDC shows the mortality rates for pediatric cancers is in decline. A study published by the CDC found that during 1999–2014, the cancer death rate for patients aged 1–19 years in the United States dropped 20%. What is also changing are the type of patients dying. In 1999, leukemia was the leading killer of childhood cancer. That has been replaced by brain cancer. Numerous other trends were also observed in the study.

Brain Cancer Surpasses Leukemia as Leading Cancer Causing Death in Children In both 1999 and 2014, more than one ­half of all cancer deaths among children and adolescents 1­-19 years old were attributable to either leukemia or brain cancer. 3 out of 10 cancer deaths among children and adolescents aged 1–19 years in 1999 were due to leukemia (29.7%), and 1 in 4 were due to brain cancer (23.7%). By 2014, these percentages reversed and brain cancer was the most common site, accounting for 29.9% of total cancer deaths.

Stem Cells May Speed Up Screening of Drugs for Rare Brain Cancers

August 9th, 2016

Researchers in Neuropathology and the Johns Hopkins Kimmel Cancer Center say they have developed a system that uses transformed human stem cells to speed up screening of existing drugs that might work against rare brain and other cancers.

A report on their proof-of-concept work, published in the Aug. 1 issue of Clinical Cancer Research, describes experiments that transform human stem cells into an aggressive and rare form of pediatric brain cancer called medulloblastoma. Those cancer cells’ genetic profiles can then be rapidly compared with hundreds of common, lab-grown human cancer cells already tested against existing drugs.

By creating a cell model of medulloblastoma from human cells rather than working with mouse cells, the researchers say they can be more confident that patients’ response to the drugs identified in the screenings may be more comparable to humans, according to Eric Raabe, M.D., Ph.D., an assistant professor of oncology at the Johns Hopkins University School of Medicine and a member of the Johns Hopkins Kimmel Cancer Center. He worked together with Charles Eberhart, MD PhD and pathobiology graduate student Allison Hanaford to create the model.

Standard treatment for pediatric medulloblastoma, which strikes 500 children per year in the United States, combines radiation and chemotherapy, but a subtype known as Group 3 — which makes up 28 percent of the cases — tends to cause the most relapses in patients, and the survival rate is only 30 to 40 percent, says Raabe. “Overall, 70 to 80 percent of medulloblastoma patients treated with conventional radiation and drug therapy survive and are considered cured,” he adds, “but many patients with the Group 3 subtype don’t fare as well.”

In recent years, one strategy scientists use to find new or better treatments is to look to databases of existing drugs that have been matched to the genetic profiles of lab-grown cells for common cancers. However, Raabe says, rare cancers and their subtypes are not well-represented in such databases, and creating such lab-grown cell lines directly from patients’ tumors is difficult. Moreover, he adds, such tumor-derived cells sometimes acquire genetic changes that can vary from the original tumor.

For the study, the scientists used lentiviruses as a transport system to insert cancer-related genes common to Group 3 medulloblastomas in human neural stem cells. As the stem cells replicate, the cancer-linked genes transform the stem cells into cancer cells. The tumors then grown from these transformed cell lines “compare very well biologically to actual human medulloblastoma, and their gene expression profile fits with that of human tumor cells,” Raabe notes.

Raabe and his colleagues then used RNA sampled from the new tumors to create a “signature” of gene expression that they could compare to similar signatures in three large databases of cell lines that have been screened and matched with existing drugs. “We wanted to find whether the cells we created matched any of these existing signatures,” Raabe explains, “because if they did, then we would have some idea of what kinds of drugs are more or most likely to kill these cells. We didn’t have to do the laborious screening to test 100,000 compounds against our own cells.”

Using this method, the scientists zeroed in on a group of compounds called CDK inhibitors that may be promising treatments for Group3 medulloblastoma, Raabe says.

One of those drugs, palbociclib, is already approved by the U.S. Food and Drug Administration for treating a type of advanced breast cancer, Raabe says. When he and his colleagues added palbociclib to their transformed cell lines, they found that the drug decreased cell line growth by more than 50 percent and more than tripled cell death compared to untreated cells. The drug also extended the survival of mice implanted with tumors grown from established Group 3 human medulloblastoma cell lines by nearly 50 percent, from 25 to 37 days.

Raabe says that palbociclib and other such drugs, called cyclin-dependent kinase inhibitors, are being tested in phase I clinical trials in children with various brain tumors. “There is interest in testing these agents in more advanced studies specifically for recurrent medulloblastoma, potentially in combination with other new agents,” he says.

Although it took several years to develop this model of Group 3 medulloblastoma and show its similarity to primary tumors, Raabe says, “This system may be one way to find drugs for rare cancers for which there are only a few human cell lines or to model very rare subtypes of adult and pediatric cancers.”

Other scientists who contributed to the research include Allison Hanaford, Antoinette Price and Charles Eberhart at Johns Hopkins; Tenley C Archer, Jong Wook Kim, Tobias Ehrenberger, Paul A. Clemons, Vlado Daník, Brinton Seashore-Ludlow, Vasanthi Viswanathan, Michelle L Stewart, Matthew G. Rees, Alykhan Shamji, Stuart Schreiber, Ernest Fraenkel, Scott L. Pomeroy, Jill P. Mesirov, and Pablo Tamayo of the Broad Institute at MIT and Harvard; Ulf D. Kahlert and Jarek Maciaczyk of Heinrich-Heine University Hospital Duesseldorf, Germany; and Guido Nikkhah of University Hospital Stuttgart, Germany.

Funding for the study was provided by the St. Baldrick’s Foundation, Hyundai Hope on Wheels, Giant Food’s Pediatric Cancer Research Fund, the Spencer Grace Foundation, the Deming Family, the Children’s Brain Tumor Foundation, the National Cancer Institute (P30 CA006973, R01NS055089, U01CA176152), the National Institutes of Health (R01 CA154480, R01 109467, R01GM074024) and the Comprehensive Cancer Center Freiburg.

Genetically Engineered Mice Suggest New Model for How Alzheimer’s Disease Causes Dementia

July 5th, 2016

Using a novel, newly developed mouse model that mimics the development of Alzheimer’s disease in humans, Johns Hopkins researchers say they have been able to determine that a one-two punch of major biological “insults” must occur in the brain to cause the dementia that is the hallmark of the disease. A description of their experiments is published online in the journal Nature Communications.

For decades, Alzheimer’s disease, the most common cause of dementia, has been known to be associated with the accumulation of so-called neurofibrillary tangles, consisting of abnormal clumps of a protein called tau inside brain nerve cells, and by neuritic plaques, or deposits of a protein called beta-amyloid outside these cells along with dying nerve cells, in brain tissue.

In Alzheimer’s disease, tau bunches up inside the nerve cells and beta-amyloid clumps up outside these cells, mucking up the nerve cells controlling memory, notes Philip C. Wong, Ph.D., professor of pathology at the Johns Hopkins University School of Medicine.

What hasn’t been clear is the relationship and timing between those two clumping processes, since one is inside cells and one is outside cells, says lead and corresponding study author Tong Li, Ph.D., an assistant professor of pathology at Johns Hopkins. Prior studies of early-onset Alzheimer’s disease have suggested that the abnormal accumulation of beta-amyloid in the brain somehow triggers the aggregation of tau leading directly to dementia and brain cell degeneration. But the new research from Li, Wong and colleagues suggests that the accumulation of beta-amyloid in and of itself is insufficient to trigger the conversion of tau from a normal to abnormal state. Instead, their studies show, it may set off a chain of chemical signaling events that lead to the “conversion” of tau to a clumping state and subsequent development of symptoms.

“For the first time, we think we understand that the accumulation of amyloid plaque alone can damage the brain, but that’s actually not sufficient to drive the loss of nerve cells or behavioral and cognitive changes,” Wong says. “What appears to be needed is a second insult — the conversion of tau — as well.”

In humans, the lag between development of the beta-amyloid plaques and the tau tangles inside brain nerve cells can be 10 to 15 years or more, Li says, but because the lifetime of a mouse is only two to three years, current animal models that successfully mimic the appearance of beta-amyloid plaques did not offer enough time to observe the changes in tau.

To address that problem, the Johns Hopkins researchers genetically engineered a mouse model that used a tau fragment to promote the clumping of normal tau protein. They then cross-bred these mice with mice engineered to accumulate beta-amyloid. The result was a mouse model that developed dementia in a manner more similar to what happens in humans, Li says.

The researchers found during brain dissections of the animals that the presence of beta-amyloid plaque alone was not sufficient to cause the biochemical conversion of tau, the repeat domain of tau — the part of tau protein that is responsible for the conversion of normal tau to an abnormal state — alone was insufficient for the conversion of tau, beta-amyloid plaques must be present in the brain for the conversion of tau and the tau fragments could “seed” the plaque-dependent pathological conversion of tau.

One implication of the new research, Wong says, is to possibly explain why some drugs designed to attack the disease after the conversion of tau haven’t worked. “The timing may be off,” he says. “If you were to intervene in the time period before the conversion of tau, you might have a good chance of ameliorating the deficits, brain cell loss and ensuing consequence of the disease.”

The work also suggests that combination therapy designed to prevent both the beta-amyloid plaque formation as well as pathological conversion of tau may provide optimal benefit for Alzheimer’s disease, the researchers say. Their mouse model could be used to test new therapies.

An estimated 5.4 million Americans are living with Alzheimer’s disease, according to 2016 statistics from the Alzheimer’s Association. There is no cure, but there are some medications that may help stabilize cognition for a limited time or help with related depression, anxiety or hallucinations.

Co-authors were Kerstin E. Braunstein, Juhong Zhang, Ashley Lau, Leslie Sibener and Christopher Deeble of Johns Hopkins.

The work was supported by the Ellison Medical Foundation, the Brain Science Institute at Johns Hopkins, the Johns Hopkins University Neuropathology Pelda Fund and the Johns Hopkins Alzheimer’s Disease Research Center.

Dr. Barbara Crain Receives Award From AANP

June 22nd, 2016

Michael N. Hart, MD presented Dr. Crain with an award for her many Crain award 2016 AANP smmeritorious contributions on behalf of members of the American Association of Neuropathologists at their 92nd annual meeting. Drs. Crain and Troncoso are show after she received the award.