Cambridge, MA, United States
Cambridge, MA, United States

Time filter

Source Type

News Article | November 14, 2016
Site: www.eurekalert.org

A non-invasive protocol testing the ability to recognize, remember and distinguish between odors was able to identify older individuals who - according to genetic, imaging and more detailed memory tests - were at increased risk of Alzheimer's disease. The report of a study by a team of Massachusetts General Hospital (MGH) investigators has been published online in Annals of Neurology. "There is increasing evidence that the neurodegeneration behind Alzheimer's disease starts at least 10 years before the onset of memory symptoms," says Mark Albers, MD, PhD, of the MGH Department of Neurology, the principal investigator and corresponding author of the report. "The development of a digitally-enabled, affordable, accessible and non-invasive means to identify healthy individuals who are at risk is a critical step to developing therapies that slow down or halt Alzheimer's disease progression." It is well known that brain circuits that process olfactory information can be affected by Alzheimer's disease, and several studies have documented a diminished ability to identify odors in affected individuals. Other studies have associated deficits in odor identification with established Alzheimer's disease biomarkers and with greater rates of cognitive decline, but the most commonly used test of olfactory ability - the University of Pennsylvania Smell Identification Test - has a number of limitations and does not take into account the great variation in olfactory ability among healthy individuals. The battery of four tests developed by the MGH team addresses both olfactory and cognitive functions: The study recruited 183 participants, most of whom were enrolled in ongoing studies at the MGH-based Massachusetts Alzheimer's Disease Research Center. At the time of the olfactory testing, 70 were cognitively normal, 74 tested normal on cognitive tests but were personally concerned about their cognitive abilities, 29 had mild cognitive impairment and 10 had been diagnosed with possible or probable Alzheimer's disease. As part of the studies they were enrolled in, all of them had comprehensive medical and neurological examinations - including annual tests of their memory and cognitive abilities - and several had brain imaging studies of Alzheimer's-associated factors. Results of the OPID-20 test significantly differentiated among the four groups of participants, and those results correlated with the thinning of two brain regions - the hippocampus and the entorhinal cortex - previously associated with Alzheimer's risk. Participants' ability to remember a previously presented aroma, as reflected in the POEM score, also showed significant differences between the two cognitively normal groups and participants with Alzheimer's disease, whose results were no better than chance. Because the ability of normal individuals to recognize and discriminate between odors can vary by as much as 40 times, the POEM scores of the two cognitively normal groups were compared with what would have been predicted based on their ability to identify and differentiate between odors, as reflected in the OAS and OD tests. That comparison determined whether each individual was a good or poor POEM performer, and poor POEM performers were more likely to have the variant of the APOE gene associated with increased Alzheimer's risk. While results of an annual test of short-term memory improved year-to-year for the good POEM performers, no such improvement was seen among the poor performers, who also showed thinning of the entorhinal cortex. Albers and his colleagues are currently recruiting participants for a larger-scale study to validate these results. "It is well recognized that early diagnosis and intervention are likely to produce the most effective therapeutic strategy for Alzheimer's disease - preventing the onset or the progression of symptoms," he says. "If these results hold up, this sort of inexpensive, noninvasive screening could help us identify the best candidates for novel therapies to prevent the development of symptoms of this tragic disease." Along with Albers, who is an assistant professor of Neurology at Harvard Medical School, the co-authors of the Annals of Neurology paper are lead author Alefiya Dhilla Albers, PhD, Mary Delaney, Kathleen Kelly, Teresa Gomez-Isla, MD, PhD, Reisa Sperling, MD, and Bradley Hyman, MD, PhD, MGH Neurology; Deborah Blacker, MD, ScD, MGH Psychiatry; Keith Johnson, MD, MGH Radiology; Josephine Asafu-Adjei, PhD, University of North Carolina; Rebecca Betensky, PhD, Harvard T.H. Chan School of Public Health; and Lloyd Hastings, PhD, Osmic Enterprises. Support for the study includes National Institutes of Health grants DP2-OD000662, P30-AG036449, P50-AG005134, and T32NS048005 and grants from the Wilkens Foundation and the Harvard NeuroDiscovery Center. Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH Research Institute conducts the largest hospital-based research program in the nation, with an annual research budget of more than $800 million and major research centers in HIV/AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, photomedicine and transplantation biology. The MGH topped the 2015 Nature Index list of health care organizations publishing in leading scientific journals, earned the prestigious 2015 Foster G. McGaw Prize for Excellence in Community Service. In August 2016 the MGH was once again named to the Honor Roll in the U.S. News & World Report list of "America's Best Hospitals."


News Article | October 26, 2016
Site: www.eurekalert.org

Use of a novel approach to analyzing brain structure that focuses on the shape rather than the size of particular features may allow identification of individuals in early presymptomatic stages of Alzheimer's disease. A team of Massachusetts General Hospital (MGH) investigators using advanced computational tools to analyze data from standard MRI scans report that individuals with Alzheimer's disease, including those diagnosed partway through a multi-year study, had greater levels of asymmetry - differences in shape between the left and right sides of the brain - of key brain structures. Their study has been published online in the journal Brain. "Our results show for the first time that asymmetry of the hippocampus and amygdala increases with disease severity, above and beyond age-associated effects," says Christian Wachinger, PhD, formerly with the Martinos Center for Biomedical Imaging at MGH, the lead author of the report. "By studying the progression of asymmetry from mild cognitive impairment to dementia, we demonstrated that greater asymmetry in those and a few other structures can predict disease progression and could be a biomarker allowing early detection of dementia." Wachinger is part of a team led by Martin Reuter, PhD, of the Martinos Center, that developed BrainPrint, a computer-aided system for representing the whole brain based on the shapes rather than the size or volume of structures. Originally described in a 2015 article in NeuroImage, BrainPrint appears to be as accurate as a fingerprint in distinguishing among individuals. In a recent paper in the same journal, Wachinger and Reuter demonstrated the use of BrainPrint for automated diagnosis of Alzheimer's disease. The current study used BrainPrint to analyze structural asymmetries in a series of MR images of almost 700 participants in the National Institute of Health-sponsored Alzheimer's Disease Neuroimaging Initiative (ADNI). Participation in that study involves MR brain imaging taken upon enrollment and repeated every 6 to 12 months, along with cognitive and genetic testing; and the MGH study analyzed data from ADNI participants with at least three MRI scans. Participants were divided into four groups: those diagnosed with probable Alzheimer's when entering the study, healthy controls with no sign of dementia, individuals with mild cognitive impairment that remained stable over the two to three years for which scans were available, and those with mild cognitive impairment that progressed to Alzheimer's disease during the study. BrainPrint analysis of the data revealed that initial, between-hemisphere differences in the shapes of the hippocampus and amygdala - structures known to be sites of neurodegeneration in Alzheimer's disease - were highest in individuals with dementia and lowest in healthy controls. Among those originally classified with mild cognitive impairment, baseline asymmetry was higher in those that progressed to Alzheimer's dementia and became even greater as symptoms developed. Increased asymmetry was also associated with poorer cognitive test scores and with increased cortical atrophy. The senior author of the Brain paper, Reuter explains, "Several studies have indicated that Alzheimer's has different effects in different sub-structures of the hippocampus and amygdala. Since the shape descriptors of BrainPrint are more sensitive to subtle changes within a structure than are standard volume-based measures, they are better suited to quantify early disease effects and predict future progression, which opens up new research directions into the mechanisms that cause these asymmetries. For example, in addition to asymmetric distribution of amyloid beta, which has been reported, the differences could reflect disease subtypes that affect hemispheres differently." Now a professor of Neurobiological Research in the Department of Child and Adolescent Psychiatry, Psychosomatics, and Psychotherapy at Ludwig Maximilian University of Munich, Wachinger adds, "In collaboration with colleagues at the Martinos Center, we are planning further exploration of the relationship between shape asymmetries and established Alzheimer's disease biomarkers to better understand the underlying biological mechanisms. Differentiating between those with stable mild cognitive impairment and those who will progress to Alzheimer's is of great clinical relevance, as it could help select individuals appropriate for clinical trials of disease-modifying therapies." Reuter is an assistant professor of Radiology and of Neurology at Harvard Medical School and director of the Laboratory for Computational Longitudinal Neuroimaging at the Martinos Center. He also holds a research affiliation at the Massachusetts Institute of Technology. Additional co-authors of the Brain paper are David Salat, PhD, Martinos Center, and Michael Weiner, MD, University of California, San Francisco. Support for the study includes National Institutes of Health grant 1K25CA181632, Massachusetts Alzheimer's Disease Research Center grant 5P50AG005134, and grants from the Humboldt Foundation, MGH Neurology Clinical Trials Unit, the Harvard NeuroDiscovery Center, and the Genentech Foundation. Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH Research Institute conducts the largest hospital-based research program in the nation, with an annual research budget of more than $800 million and major research centers in HIV/AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, photomedicine and transplantation biology. The MGH topped the 2015 Nature Index list of health care organizations publishing in leading scientific journals, earned the prestigious 2015 Foster G. McGaw Prize for Excellence in Community Service. In August 2016 the MGH was once again named to the Honor Roll in the U.S. News & World Report list of "America's Best Hospitals."


News Article | October 28, 2016
Site: www.biosciencetechnology.com

A novel approach to analyzing brain structure that focuses on the shape, rather than the size, of particular features may allow identification of individuals who are in the early, pre-symptomatic stages of Alzheimer’s disease. A team of Harvard Medical School investigators at Massachusetts General Hospital used advanced computational tools to analyze data from standard MRI scans. They found that people with Alzheimer’s disease, including those diagnosed partway through a multiyear study, had greater levels of asymmetry in key brain structures: differences in shape between the left and right sides of the brain. Their study has been published in the journal Brain. "Our results show for the first time that asymmetry of the hippocampus and amygdala increases with disease severity, above and beyond age-associated effects,” said Christian Wachinger, formerly an HMS research fellow in neurology at Mass General and lead author of the report. “By studying the progression of asymmetry from mild cognitive impairment to dementia, we demonstrated that greater asymmetry in those and a few other structures can predict disease progression and could be a biomarker allowing early detection of dementia.” Wachinger is part of a team led by Martin Reuter, HMS assistant professor of radiology at Mass General, that developed BrainPrint, a computer-aided system for representing the whole brain based on the shape, rather than the size or volume, of structures. Originally described in a 2015 article in NeuroImage, BrainPrint appears to be as accurate as a fingerprint in distinguishing among individuals. In a recent paper in the same journal, Wachinger and Reuter demonstrated the use of BrainPrint for automated diagnosis of Alzheimer’s disease. The current study used BrainPrint to analyze structural asymmetries in a series of MR images of almost 700 participants in the National Institutes of Health-sponsored Alzheimer’s Disease Neuroimaging Initiative. Participation in that study involves MR brain imaging taken upon enrollment and repeated every 6 to 12 months, along with cognitive and genetic testing. The Mass General study analyzed data from participants who had had at least three MRI scans. Participants were divided into four groups: those diagnosed with probable Alzheimer’s when entering the study, healthy controls with no sign of dementia, individuals with mild cognitive impairment that remained stable over the two to three years for which scans were available, and those with mild cognitive impairment that progressed to Alzheimer’s disease during the study. BrainPrint analysis of the data revealed that initial, between-hemisphere differences in the shapes of the hippocampus and amygdala—structures known to be sites of neurodegeneration in Alzheimer’s disease—were highest in individuals with dementia and lowest in healthy controls. Among those originally classified with mild cognitive impairment, baseline asymmetry was higher in those that progressed to Alzheimer’s dementia and became even greater as symptoms developed. Increased asymmetry was also associated with poorer cognitive test scores and with increased cortical atrophy. Several studies have indicated that Alzheimer’s has different effects in different substructures of the hippocampus and amygdala, said Reuter, the senior author of the Brain paper, explained. “Since the shape descriptors of BrainPrint are more sensitive to subtle changes within a structure than are standard volume-based measures, they are better suited to quantify early disease effects and predict future progression, which opens up new research directions into the mechanisms that cause these asymmetries,” Reuter said. “For example, in addition to asymmetric distribution of amyloid beta, which has been reported, the differences could reflect disease subtypes that affect hemispheres differently.” Now a professor of neurobiological research in the Department of Child and Adolescent Psychiatry, Psychosomatics, and Psychotherapy at Ludwig Maximilian University of Munich, Wachinger said that in collaboration with colleagues at Mass General, he is planning to explore further the relationship between shape asymmetries and established Alzheimer’s disease biomarkers to better understand the underlying biological mechanisms. “Differentiating between those with stable mild cognitive impairment and those who will progress to Alzheimer’s is of great clinical relevance, as it could help select individuals appropriate for clinical trials of disease-modifying therapies,” Wachinger said. Reuter is director of the Laboratory for Computational Longitudinal Neuroimaging at the Martinos Center at Mass General. He also holds a research affiliation at MIT. Support for the study includes National Institutes of Health grant 1K25CA181632, Massachusetts Alzheimer’s Disease Research Center grant 5P50AG005134, and grants from the Humboldt Foundation, MGH Neurology Clinical Trials Unit, the Harvard NeuroDiscovery Center, and the Genentech Foundation.


News Article | December 1, 2016
Site: www.eurekalert.org

Boston, MA-- Although the hallmark symptoms of Parkinson's disease (PD) - such as involuntary shaking, slowness of movement and muscle rigidity - are related to movement, recent evidence has suggested that memory impairment plays an outsized role in diminished quality of life and the burden placed on caregivers. A new study led by investigators in the Ann Romney Center for Neurological Diseases at Brigham and Women's Hospital finds that mutations in the gene for glucocerebrosidase (GBA), known to be a risk factor for PD, also have a powerful influence on the development of cognitive decline. The study is available online and published in the November edition of Annals of Neurology, the journal of the American Neurological Association. "I believe this is the dawn of personalized medicine for Parkinson's disease," said corresponding author Clemens Scherzer, MD, associate professor of Neurology, who leads the Neurogenomics Lab and Parkinson Personalized Medicine Initiative of Brigham and Women's Hospital and Harvard Medical School. "This is one of the largest longitudinal assessments of patients with Parkinson's disease, and we believe that its insights will help to fix what is currently broken with clinical trials for patients. We see more precise clinical trials that will help match the right therapist with the right patient as the next logical step." Two defective copies of the GBA gene are known to cause Gaucher's disease, a childhood disorder that causes death by age two or severe neurologic complications. One defective copy of the gene was once thought to be of little consequence, but has recently emerged as a common risk factor for Parkinson's disease. The new report examined 2,304 patients from the US, Canada and Europe, finding that 10 percent carried one (or more) defects in copies of the GBA gene. Patients carrying one defective GBA gene copy had an increased risk of memory troubles. This effect was most troublesome for patients carrying a GBA copy with the most severe type of defect -- known as a neuropathic GBA mutation -- whose risk of developing cognitive decline over time was increased by 217 percent. Approximately half of the carriers of a neuropathic GBA mutation developed global cognitive impairment within ten years of being diagnosed with Parkinson's. Among the PD patients without a mutation, only about 20 percent developed this decline in cognitive function. Therapies for Gaucher disease have been available since 1994. Scherzer and colleagues hope that their findings will open the door for a completely new type of clinical trials in Parkinson's -- GBA-directed trials designed to proactively prevent memory troubles in patients with movement-related symptoms. They estimate that such innovative, nimble trials would need 25-fold fewer patients then conventional trials, with reduced costs and a better chance of success. More than 15 previous clinical trials for medications designed to slow or halt Parkinson's have been inconclusive or failed, perhaps in part, Scherzer notes, due to cumbersome and inefficient trial designs. Scherzer and his colleagues hope that their findings will breathe new life into better trial design and interest from pharmaceutical companies to tackle Parkinson's. "We have now launched a Consortium with The Michael J. Fox Foundation and industry to put together a tool kit for GBA-directed, molecularly targeted trials in PD," said Scherzer. "This tool kit will be an open resource for all scientists and pharma, and will comprise gene tests, biomarkers, and clinical parameters needed for successful proof-of-concept trials in PD. Smaller, more efficient trials remove a big entry barrier for pharma companies. This is good news for drug development and patients." The new work represents seven international, longitudinal studies, and a collaboration among Scherzer and colleagues from the International Genetics of Parkinson Disease Progression (IGPP) Consortium. This study was supported by The Michael J. Fox Foundation; the National Institutes of Health; Harvard NeuroDiscovery Center; U.S. Department of Defense; M.E.M.O. Hoffman Foundation; Parkinson's Disease Foundation; Wellcome Trust; MRC; Parkinson's UK; Cure-PD; Patrick Berthoud Trust; Van Geest Foundation; NIHR; Assistance Publique Hôpitaux de Paris; French clinical research hospital program-PHRC; "Investissements d'Avenir"; Prinses Beatrix Fonds; Stichting Alkemade-Keuls; and Stichting ParkinsonFonds. Paper cited: Liu G et al. "Neuropathic Gaucher's mutations accelerate cognitive decline in Parkinson's" Annals of Neurology DOI: 10.1002/ana.2478 Brigham and Women's Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare. BWH has more than 4.2 million annual patient visits and nearly 46,000 inpatient stays, is the largest birthing center in Massachusetts and employs nearly 16,000 people. The Brigham's medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in patient care, quality improvement and patient safety initiatives, and its dedication to research, innovation, community engagement and educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Brigham Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, more than 3,000 researchers, including physician-investigators and renowned biomedical scientists and faculty supported by nearly $666 million in funding. For the last 25 years, BWH ranked second in research funding from the National Institutes of Health (NIH) among independent hospitals. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies and the Women's Health Initiative as well as the TIMI Study Group, one of the premier cardiovascular clinical trials groups. For more information, resources and to follow us on social media, please visit BWH's online newsroom.


Cesani M.,San Raffaele Scientific Institute | Cesani M.,Harvard University | Cavalca E.,San Raffaele Scientific Institute | Macco R.,Vita-Salute San Raffaele University | And 16 more authors.
Annals of Neurology | Year: 2014

Objective To facilitate development of novel disease-modifying therapies for lysosomal storage disorder (LSDs) characterized by nervous system involvement such as metachromatic leukodystrophy (MLD), molecular markers for monitoring disease progression and therapeutic response are needed. To this end, we sought to identify blood transcripts associated with the progression of MLD. Methods Genome-wide expression analysis was performed in primary T lymphocytes of 24 patients with MLD compared to 24 age- and sex-matched healthy controls. Genes associated with MLD were identified, confirmed on a quantitative polymerase chain reaction platform, and replicated in an independent patient cohort. mRNA and protein expression of the prioritized gene family of metallothioneins was evaluated in postmortem patient brains and in mouse models representing 6 other LSDs. Metallothionein expression during disease progression and in response to specific treatment was evaluated in 1 of the tested LSD mouse models. Finally, a set of in vitro studies was planned to dissect the biological functions exerted by this class of molecules. Results Metallothionein genes were significantly overexpressed in T lymphocytes and brain of patients with MLD and generally marked nervous tissue damage in the LSDs here evaluated. Overexpression of metallothioneins correlated with measures of disease progression in mice and patients, whereas their levels decreased in mice upon therapeutic treatment. In vitro studies indicated that metallothionein expression is regulated in response to oxidative stress and inflammation, which are biochemical hallmarks of lysosomal storage diseases. Interpretation Metallothioneins are potential markers of neurologic disease processes and treatment response in LSDs.Ann Neurol 2014;75:127-137 © 2013 Child Neurology Society/American Neurological Association.


Liu M.,Harvard NeuroDiscovery Center | Dobson B.,Harvard NeuroDiscovery Center | Glicksman M.A.,Harvard NeuroDiscovery Center | Yue Z.,Mount Sinai School of Medicine | Stein R.L.,Sirtris Pharmaceuticals
Biochemistry | Year: 2010

Recent studies have identified mutations in the leucine-rich repeat kinase2 gene (LRRK2) in the most common familial forms and some sporadic forms of Parkinson's disease (PD). LRRK2 is a large and complex protein that possesses kinase and GTPase activities. Some LRRK2 mutants enhance kinase activity and possibly contribute to PD through a toxic gain-of-function mechanism. Given the role of LRRK2 in the pathogenesis of PD, understanding the kinetic mechanism of its two enzymatic properties is critical for the discovery of inhibitors of LRRK2 kinase that would be therapeutically useful in treating PD. In this report, by using LRRK2 protein purified from murine brain, first we characterize kinetic mechanisms for the LRRK2-catalyzed phosphorylation of two peptide substrates: PLK-derived peptide (PLK-peptide) and LRRKtide. We found that LRRK2 follows a rapid equilibrium random mechanism for the phosphorylation of PLK-peptide with either ATP or PLK-peptide being the first substrate binding to the enzyme, as evidenced by initial velocity and inhibition mechanism studies with nucleotide analogues AMP and AMP-PNP, product ADP, and an analogue of the peptide substrate. The binding of the first substrate has no effect on the binding affinity of the second substrate. Identical mechanistic conclusions were drawn when LRRKtide was the phosphoryl acceptor. Next, we characterize the GTPase activity of LRRK2 with a kcat of 0.2 ± 0.02 s -1 and a Km of 210 ± 29 μM. A SKIE of 0.97 ± 0.04 was measured on kcat for the GTPase activity of LRRK2 in a D2O molar fraction of 0.86 and suggested that the product dissociation step is rate-limiting, of the steps governed by kcat in the LRRK2-catalyzed GTP hydrolysis. Surprisingly, binding of GTP, GDP, or GMP has no effect on kinase activity, although GMP and GDP inhibit the GTPase activity. Finally, we have identified compound LDN-73794 through screen of LRRK2 kinase inhibitors. Our study revealed that this compound is a competitive inhibitor of the binding of ATP and inhibits the kinase activity without affecting the GTPase activity. © 2010 American Chemical Society.


Liu M.,Harvard NeuroDiscovery Center | Girma E.,Harvard NeuroDiscovery Center | Glicksman M.A.,Harvard NeuroDiscovery Center | Stein R.L.,Sirtris Pharmaceuticals
Biochemistry | Year: 2010

Cdk5/p25 is a member of the cyclin-dependent, Ser/Thr kinase family and has been identified as one of the principle Alzheimers disease-associated kinases that promote the formation of hyperphosphorylated tau, the major component of neurofibrillary tangles. We and others have been developing inhibitors of cdk5/p25 as possible therapeutic agents for Alzheimers disease (AD). In support of these efforts, we examine the metal effect and solvent kinetic isotope effect on cdk5/p25-catalyzed H1P (a histone H-1-derived peptide) phosphorylation. Here, we report that a second Mg2+ in addition to the one forming the MgATP complex is required to bind to cdk5/p25 for its catalytic activity. It activates cdk5/p25 by demonstrating an increase in kcat and induces a conformational change that favors ATP binding but has no effect on the binding affinity for the H1P peptide substrate. The binding of the second Mg 2+ does not change the binding order of substrates. The reaction follows the same rapid equilibrium random mechanism in the presence or absence of the second Mg2+ as evidenced by initial velocity analysis and substrate analogue and product inhibition studies. A linear proton inventory with a normal SKIE of 2.0 ± 0.1 in the presence of the second Mg 2+ was revealed and suggested a single proton transfer in the rate-limiting phosphoryl transfer step. The pH profile revealed a residue with a pKa of 6.5 that is most likely the general acid-base catalyst facilitating the proton transfer. © 2010 American Chemical Society.


Androutsellis-Theotokis A.,U.S. National Institutes of Health | Androutsellis-Theotokis A.,Academy of Athens | Rueger M.A.,U.S. National Institutes of Health | Rueger M.A.,University of Cologne | And 12 more authors.
PLoS ONE | Year: 2010

Background: The ability to grow a uniform cell type from the adult central nervous system (CNS) is valuable for developing cell therapies and new strategies for drug discovery. The adult mammalian brain is a source of neural stem cells (NSC) found in both neurogenic and non-neurogenic zones but difficulties in culturing these hinders their use as research tools [1,2,3,4,5,6]. Methodology/Principal Findings: Here we show that NSCs can be efficiently grown in adherent cell cultures when angiogenic signals are included in the medium. These signals include both anti-angiogenic factors (the soluble form of the Notch receptor ligand, Dll4) and pro-angiogenic factors (the Tie-2 receptor ligand, Angiopoietin 2). These treatments support the self renewal state of cultured NSCs and expression of the transcription factor Hes3, which also identifies the cancer stem cell population in human tumors. In an organotypic slice model, angiogenic factors maintain vascular structure and increase the density of dopamine neuron processes. Conclusions/Significance: We demonstrate new properties of adult NSCs and a method to generate efficient adult NSC cultures from various central nervous system areas. These findings will help establish cellular models relevant to cancer and regeneration.


Ray S.,Harvard NeuroDiscovery Center | Bender S.,Harvard NeuroDiscovery Center | Bender S.,Harvard University | Kang S.,Harvard NeuroDiscovery Center | And 7 more authors.
Journal of Biological Chemistry | Year: 2014

The effect of leucine-rich repeat kinase 2 (LRRK2) mutation I2020T on its kinase activity has been controversial, with both increased and decreased effects being reported. We conducted steady-state and pre-steady-state kinetic studies on LRRKtide and its analog LRRKtideS. Their phosphorylation differs by the rate-limiting steps: product release is rate-limiting for LRRKtide and phosphoryl transfer is rate-limiting for LRRKtideS. As a result, we observed that the I2020T mutant is more active than wild type (WT) LRRK2 for LRRKtideS phosphorylation, whereas it is less active than WT for LRRKtide phosphorylation. Our pre-steady-state kinetic data suggest that (i) the I2020T mutant accelerates the rates of phosphoryl transfer of both reactions by 3-7-fold; (ii) this increase is masked by a rate-limiting product release step for LRRKtide phosphorylation; and (iii) the observed lower activity of the mutant for LRRKtide phosphorylation is a consequence of its instability: the concentration of the active form of the mutant is 3-fold lower than WT. The I2020T mutant has a dramatically low KATP and therefore leads to resistance toATPcompetitive inhibitors.Twowell known DFGout or type II inhibitors are also weaker toward the mutant because they inhibit the mutant in an unexpected ATP competitive mechanism. The I2020 residue lies next to the DYGmotif of the activation loop of the LRRK2 kinase domain. Our modeling and metadynamic simulations suggest that the I2020T mutant stabilizes the DYG-in active conformation and creates an unusual allosteric pocket that can bind type II inhibitors but in an ATP competitive fashion. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Loading Harvard NeuroDiscovery Center collaborators
Loading Harvard NeuroDiscovery Center collaborators