Parkinson’s disease biomarker found in patient urine samples
Andrew WestFor more than five years, urine and cerebral-spinal fluid samples from patients with Parkinson’s disease have been locked in freezers in the NINDS National Repository, stored with the expectation they might someday help unravel the still-hidden course of this slow-acting neurodegenerative disease.
Now, research by Andrew West, Ph.D., and colleagues at the University of Alabama at Birmingham has revealed that the tubes hold a brand-new type of biomarker — a phosphorylated protein that correlates with the presence and severity of Parkinson’s disease. West and colleagues, with support from the National Institutes of Health, the Michael J. Fox Foundation for Parkinson’s Disease Research and the Parkinson’s Disease Foundation, are digging deeper into these biobanked samples, to validate the biomarker as a possible guide for future clinical treatments and a monitor of the efficacy of potential new Parkinson’s drugs in real time during treatment.
“Nobody thought we’d be able to measure the activity of this huge protein called LRRK2 (pronounced lark two) in biofluids since it is usually found inside neurons in the brain,” said West, co-director of the Center for Neurodegeneration and Experimental Therapeutics, and the John A. and Ruth R. Jurenko Professor of Neurology at UAB. “New biochemical markers like the one we’ve discovered together with new neuroimaging approaches are going to be the key to successfully stopping Parkinson’s disease in its tracks. I think the days of blindly testing new therapies for complex diseases like Parkinson’s without having active feedback both for ‘on-target’ drug effects and for effectiveness in patients are thankfully coming to an end.”
A biomarker helps physicians predict, diagnose or monitor disease, because the biomarker corresponds to the presence or risk of disease, and its levels may change as the disease progresses. Validated biomarkers can aid both preclinical trial work in the laboratory and future clinical trials of drugs to treat Parkinson’s. West and others are paving the way for an inhibitor drug that prevented neuroinflammation and neurodegeneration in an animal model of the disease, as reported last year by West and colleagues.
The new biomarker findings were published in Neurology in March and Movement Disorders in June. The biomarker, LRRK2, has been shown to play a role in hereditary Parkinson’s, and the most common of these mutations — called G2019S — causes the LRRK2 kinase to add too many phosphates to itself and other proteins. Why this leads to Parkinson’s disease is not yet clear.
The key to West’s biomarker approach was the recognition that LRRK2 can be purified from a new type of vesicle called exosomes found in all human biofluids, like urine and saliva. Cells in the body continually release exosomes that contain a mixture of proteins, RNA and DNA derived from different kinds of cells. West and colleagues were able to purify exosomes from 3- or 4-ounce urine samples donated by patients, and then measure phosphorylated LRRK2 in those exosomes.
The findingsIn the Neurology study, they found that elevated phosphorylated LRRK2 predicted the risk for onset of Parkinson’s disease for people carrying a mutation in LRRK2, which is about 2-3 percent of all Parkinson’s disease patients. These findings were first tested with a preliminary, 14-person cohort of urine samples from the Columbia University Movement Disorders Center. That was followed by a larger replication study of 72 biobanked urine samples from the Michael J. Fox Foundation LRRK2 Cohort Consortium. All samples were provided to UAB in a blinded fashion to ensure the approach was rigorous.
|“New biochemical markers like the one we’ve discovered together with new neuroimaging approaches are going to be the key to successfully stopping Parkinson’s disease in its tracks.”
Next stepsQuestions remain for this evidence of biochemical changes in LRRK2 in idiopathic Parkinson’s disease. One is finding out where the urinary exosomes come from. Given a suspected role for inflammation in Parkinson’s disease, it is interesting that LRRK2 is highly expressed in cells of the innate immune system. A possible explanation for the phosphorylated LRRK2 in patients with more severe disease may be an increased inflammation in those patients who have aggressive progression of disease.
In May, West was awarded a new U01 collaborative grant from the National Institute of Neurological Disorders and Stroke to further explore urinary exosomes and extend the observations to cerebral-spinal fluid as a marker for disease prediction and prognosis.
Besides West, authors of the Neurology paper, “Urinary LRRK2 phosphorylation predicts parkinsonian phenotypes in G2019S LRRK2 carriers,” are Kyle B. Fraser and Mark S. Moehle, of the Center for Neurodegeneration and Experimental Therapeutics and Department of Neurology, UAB School of Medicine; and Roy N. Alcalay, M.D., Columbia University Department of Neurology.
Besides West, authors of the Movement Disorders paper, “Ser(P)-1292 LRRK2 in urinary exosomes is elevated in idiopathic Parkinson’s disease,” are Fraser, Ashlee B. Rawlins, Rachel G. Clark and David G. Standaert, M.D., Ph.D., of the UAB Center for Neurodegeneration and Experimental Therapeutics and Department of Neurology; Alcalay; and Nianjun Liu, Ph.D., Department of Biostatistics, UAB School of Public Health.
Standaert is the John N. Whitaker Professor and chair of the Department of Neurology at UAB.
The MJFF LRRK2 Cohort Consortium provided samples and is coordinated and funded in part by the Michael J. Fox Foundation for Parkinson’s Disease Research. The Parkinson’s Disease Foundation supported the collection of samples from Columbia University. Financial support for the study was provided by National Institutes of Health grants U18 NS082132, R01 NS064934, F31 NS081963, K02 NS0915 and T32 GM008111.
Brown and Limdi selected for the prestigious Executive Leadership in Academic Medicine Program
Cynthia BrownTwo members of the School of Medicine faculty have been selected as fellows for the Hedwig van Ameringen Executive Leadership in Academic Medicine® for 2016-2017. Cynthia J. Brown, M.D., MSPH, and Nita A. Limdi, PharmD, MSPH, Ph.D., both met the extensive requirements to be accepted into this elite program – two of only 54 members accepted nationwide.
ELAM is a year-long, part-time fellowship for women faculty in schools of medicine, dentistry and public health. The 2016-2017 class will be the 22nd incoming class for ELAM, which remains the only program in North America committed to preparing women for senior leadership roles in academic health science institutions.
Brown, who serves as the director of UAB’s Division of Gerontology, Geriatrics and Palliative Care and the UAB Comprehensive Center for Healthy Aging, completed her medical degree at the University of North Carolina at Chapel Hill. She served her internship and residency in the Primary Care Internal Medicine Program at Yale University School of Medicine, where she also completed a fellowship in geriatrics and clinical epidemiology. She obtained a Master’s of Science in Public Health at UAB in 2006. Limdi, who followed her PharmD from Samford with a MSPH in Clinical Research in 2005 and a doctorate in Epidemiology in 2007 (both from UAB), is a professor of Neurology and interim director of the UAB Hugh Kaul Personalized Medicine Institute.
While already boasting professional credential rich in leadership, both saw ELAM as a means to further their professional development and cultivate new avenues for growth.
“As a relatively new division director, I recognize that I have much to learn about being a leader,” Brown said. “When I took the job as division director, I shared with my chair that being recommended for this prestigious program was on my personal wish list. The program is rich with opportunities.”
Nita LimdiLimdi’s sentiments are similar. “I believe that participating in the ELAM experience will shape my professional goals and give me the tools, confidence and support to achieve them,” she said. “I am a chronic student. I always say, ‘What’s next? What can I do better?’ My goals are to further advance in research and implementation, teaching and mentorship – but also to inform policy. You can’t just stay in your lab, or people who know less than you will be the ones forming policy.”
Limdi explains that she looks forward to enhancing her leadership skills. “As scientists, we tend to stay focused on the science. But we need to develop this new facet to our skills in order to get people and organizations to understand our research and see its value. It’s about how to build and challenge teams to be transformative.”
The one-year fellowship will finish in April 2017 and include online assignments, community-building activities, and three week-long in-residence sessions. Brown and Limdi join other notable ELAM participants from UAB, including last year’s participants Robin G. Lorenz, M.D., Ph.D., assistant dean for Physician-Scientist Education and Mary T. Hawn, M.D., who is now chair of surgery at Stanford. Beyond UAB, roughly 1,000 ELAM alumnae fill leadership roles in institutions across the globe, including women who hold positions as department chairs, research center directors, deans, college presidents and chief executives in health care and accrediting organizations.
Written by Laura Coulter
Parkinson’s disease pathogenesis is reduced in a rat model using a cell-signaling inhibitor drug
By Jeff Hansen
UAB Media Relations
Results show that JAK/STAT pathway inhibitors may be a new class of therapeutic treatments for patients with Parkinson’s disease. Acting by reducing inflammation, they prevent neurodegeneration in animal models and may be an important new approach to slow progression of the disease.
Etty “Tika” Benveniste
University of Alabama at Birmingham researchers report the first documentation that suppressing a key cell-signaling pathway in a rat model of Parkinson’s disease reduces pathogenesis. Oral administration of AZD1480 — one of the JAK/STAT pathway inhibitors generally known as Jakinibs — lessened the destructive inflammation and nerve cell degradation in the area of the brain affected by Parkinson’s.
At present, there are no therapies available to patients to prevent progression of Parkinson’s disease, the chronic neurodegenerative movement disorder marked by profound loss of dopamine-producing neurons in the brain.
“We believe Jakinibs may become a viable therapeutic option for Parkinson’s disease patients,” said Etty “Tika” Benveniste, Ph.D., professor in the Department of Cell, Developmental and Integrative Biology and lead author of a paper published May 4 in The Journal of Neuroscience. “They are already being studied for other conditions, are orally bioavailable, seem to be well-tolerated, and do not promote troublesome immunosuppression. Furthermore, there may also be other ways of targeting the JAK/STAT pathway as a neuroprotective therapy for neurodegenerative disease.”
A variety of Jakinibs are in Phase I, II or III clinical trials for several other diseases. The current UAB study, funded by the Michael J. Fox Foundation for Parkinson Research and the National Institutes of Health, is the first to show that disrupting the JAK/STAT pathway prevents the neuroinflammation and neurodegradation specific to Parkinson’s disease.
“This is a very important advance,” said David Standaert, M.D., Ph.D., professor and chair of the UAB Department of Neurology and a collaborator on the project. “It shows that anti-inflammatory strategies have real potential. The next steps will be to validate some of the inflammatory changes seen in the animals in patients with Parkinson’s disease, which in turn will enable planning of clinical studies of anti-inflammatory therapies in patients with Parkinson’s.”
|“This is a very important advance. It shows that anti-inflammatory strategies have real potential. The next steps will be to validate some of the inflammatory changes seen in the animals in patients with Parkinson’s disease, which in turn will enable planning of clinical studies of anti-inflammatory therapies in patients with Parkinson’s.” — David Standaert, M.D., Ph.D.|
Benveniste and Standaert are part of an interdisciplinary UAB team focusing on neuroinflammatory mechanisms in Parkinson’s disease. The group — co-led by Benveniste, Standaert and Andrew West, Ph.D., associate professor of neurology — seeks to understand how the body’s immune system contributes to the pathology seen in the brains of Parkinson’s disease patients and to the development and progression of the disease. Only recently have researchers begun to suspect an important role for inflammation in the disease, and this is still largely uncharted territory.For the current paper, UAB researchers, led by Hongwei Qin, Ph.D., associate professor of cell, developmental and integrative biology, either challenged rat immune cells in vitro with aggregated human α-synuclein, or induced overexpression of α-synuclein carried by a virus vector in brains of rats. Untreated, this in vivo model leads to neuroinflammation in the brain and degradation of dopamine-producing neurons in the substantia nigra, the portion of the midbrain marked by cell death in Parkinson’s patients. Accumulation of α-synuclein in the brains of patients is a core feature of Parkinson’s disease, and this leads to the activation of the brain immune cells called microglia, the production of inflammatory signaling chemicals, and ultimately, neurodegradation.
In vitro and in vivo experiments showed AZD1480 inhibited JAK/STAT activation and downstream gene induction after a challenge by α-synuclein. The genes that are induced by α-synuclein, but not induced in the presence of α-synuclein and AZD1480, are associated with the proinflammatory phenotype. The inhibition by AZD1480 dampened both innate and adaptive immune responses.
Altogether, the researchers say, the results show the potential of Jakinibs to protect against the degradation of dopamine-producing neurons.
DetailsFor the in vivo neuroinflammation experiments, α-synuclein overexpression was induced, and two weeks later rats were given AZD1480 by oral gavage for 14 days. Then the researchers analyzed the inflammatory response in the substantia nigra of the midbrain for AZD1480-treated and -untreated animals. AZD1480 prevented the increased numbers of microglia and macrophages seen after α-synuclein overexpression. AZD1480 also prevented inflammatory activation of the microglia, as measured by Iba1-positive cells, and it prevented upregulation of genes for the proinflammatory markers TNF-α, iNOS, IL-6 and CCL2.
AZD1480 also prevented neurodegradation. For the in vivo neurodegradation experiments, α-synuclein overexpression was induced, and four weeks later — at the peak of neuroinflammation — rats were given a four-week treatment of AZD1480 oral gavage. At 12 weeks, the brains were analyzed for nigral neurons of the substantia nigra. Benveniste and colleagues found that overexpression of α-synuclein caused a 50 percent loss of nigral neurons at three months. But when the α-synuclein rats were also treated with AZD1480, that loss was prevented, and the numbers of nigral cells were similar to those of the controls.
In Parkinson’s disease, chronic inflammation in the brain makes the blood-brain barrier more permeable, allowing immune system T-cells to infiltrate into the brain from the bloodstream, potentially adding to neuroinflammation. In the rat model, α-synuclein overexpression increased the infiltration of CD4+ T-helper cells and induced activation of the STAT3 signaling protein. AZD1480 treatment inhibited both of these immune responses. AZD1480 also inhibited induction of two genes for proinflammatory markers, CIITA and MHC Class II.
The UAB researchers further found that α-synuclein overexpression significantly upregulated 186 genes in the midbrains of rats, while AZD1480 treatment of α-synuclein-overexpression rats inhibited the expression levels of 59 genes, the majority being genes that were induced by α-synuclein. Genes induced by α-synuclein overexpression include many that are implicated in cell signaling, inflammatory and neurological diseases, and antigen presentation (a step in the adaptive immune response).
Besides Benveniste, Qin and Standaert, authors of the paper, “Inhibition of the JAK/STAT pathway protects against α-synuclein-induced neuroinflammation and dopaminergic neurodegeneration,” are Jessica A. Buckley, Yudong Liu, Thomas H. Fox III, Gordon P. Meares, Hao Yu and Zhaoqi Yan, all of the UAB Department of Cell, Developmental and Integrative Biology; Xinru Li and Ashley S. Harms, UAB Department of Neurology; and Yufeng Li, UAB Department of Medicine.
At UAB, Benveniste holds the Charlene A. Jones Endowed Chair in Neuroimmunology, and Standaert holds the John N. Whitaker Endowed Chair in Neurology. West holds the John A. and Ruth R. Jurenko Endowed Professorship in Neurology.
Research support came from the M.J. Fox Foundation, and from NIH grants RO1 NS57563-05, P20 NS095230, P30 AR48311, P30 NS47466, P30 CA13148 and P30 AI027767.