2012 — 2014 |
Moehle, Mark S |
F31Activity Code Description: To provide predoctoral individuals with supervised research training in specified health and health-related areas leading toward the research degree (e.g., Ph.D.). |
Role of Microglial Lrrk2 in Inflammation @ University of Alabama At Birmingham
DESCRIPTION (provided by applicant): Missense mutations in LRRK2 account for between 1 and 5% of late onset PD cases in most Caucasian populations. The role of LRRK2 in idiopathic PD remains unclear, although better understanding of the signaling and physiology behind mutations in LRRK2 may help clarify pathogenic mechanisms in PD. Several lines of evidence implicate neuroinflammation in the pathogenesis of PD. While the role of LRRK2 remains unclear, several lines of evidence point to LRRK2 being involved in the innate immune response. Recent data show that LRRK2 expression and kinase activity are necessary for a full TLR4-induced pro- inflammatory response in microglia. Inflammatory markers as well as selective death of dopaminergic neurons in the substantia nigra caused by rAAV2-alpha-synuclein over-expression recapitulate aspects of PD. We hypothesize that LRRK2 may modify alpha-synuclein driven neuroinflammation, where G2019S LRRK2 exaggerates pro-inflammatory responses and LRRK2 inhibition down-regulates pro-inflammatory responses. These hypotheses will be tested in two aims: The first aim will determine whether alpha-synuclein signals through LRRK2 in primary microglia to elicit pro-inflammatory responses. Using primary microglia derived from transgenic, knockout, and control mice, the cytokine/chemokine/growth-factor response to alpha-synuclein and other pro-inflammatory stimuli will be examined. Additionally, the antigen processing/presentation capabilities of primary microglia harboring LRRK2 mutations will be examined. The second aim will determine whether LRRK2 activity and expression is necessary for rAAV2-alpha-synuclein induced inflammation and neurodegeneration, and whether G2019S-LRRK2 exacerbates neurodegeneration in the substantia nigra. Using the same animals as in aim 1, the second aim will utilize quantitative endpoints including unbiased stereological estimations of dopaminergic neurons in the substantia nigra, microglial activation, peripheral immune cell invasion, and microglia presenting antigen and inducing T-cell proliferation. Additionally, microglial polarization and activation wil be analyzed with flow cytometry. Overall, we expect to observe that G2019S LRRK2 exacerbates neurodegeneration, microglial activation, pro-inflammatory cytokine release, antigen processing/presentation, and polarization of microglia to an M1 phenotype while the knockout shows the opposite effect. The proposed training plan is sponsored by Dr. Andrew West and co-sponsored by Dr. David Standaert. Included in the training plan are experiences to help the PI gain a wide range of molecular and cellular neuroimmunology techniques, presentation of data in a written and oral format, responsibly conduct in research, and development into an independent researcher capable of carrying out high impact translation research. PUBLIC HEALTH RELEVANCE: Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder affecting between 1 and 5% of the population over 65 with an estimated annual economic impact of $35.5 billion in the US. Current therapeutic approaches treat only the symptoms of PD and offer neither a cure nor aid in slowing the progression of disease. The proposed research plan aims to uncover the molecular basis of PD and move closer to developing the most efficacious therapeutic strategies.
|
0.958 |
2019 — 2021 |
Moehle, Mark S |
K99Activity Code Description: To support the initial phase of a Career/Research Transition award program that provides 1-2 years of mentored support for highly motivated, advanced postdoctoral research scientists. R00Activity Code Description: To support the second phase of a Career/Research Transition award program that provides 1 -3 years of independent research support (R00) contingent on securing an independent research position. Award recipients will be expected to compete successfully for independent R01 support from the NIH during the R00 research transition award period. |
M4 Muscarinic Acetylcholine Receptor Signaling as a Potent Regulator of Motor Deficits
Candidate: My long term goal is to become an independent investigator running an interdisciplinary and collaborative research team to understand the mechanisms and novel treatments of neurological disorders. Specifically, my interests surround understanding how different sources of acetylcholine (ACh, i.e. cholinergic interneurons verse pedunculopontine nucleus) regulate motor dysfunction, as well as how imbalanced dopamine (DA) and M4 muscarinic acetylcholine receptor (mAChR) signaling exacerbates motor dysfunction. I have a strong background in biochemistry and electrophysiology. I propose to learn behavioral and voltammetry techniques to round out my training, and have the necessary skills to produce high impact publications and successful R01 submissions. I received my Ph.D. in April 2015, this is my last year of eligibility for the K99/R00. Training: In addition to Dr. Conn, I have an advisory committee of experts in behavioral pharmacology, Dr. Jones, dystonia and dopaminergic signaling, Dr. Ehrlich, and in using molecular probes to understand GPCR signaling, Dr. Lindsley. This committee will provide the necessary training and guidance to accomplish this proposal. Outside of the committee, we have identified, both at Vanderbilt and externally, courses, seminars, and meetings to provide further technical training, presentation experience, responsible conduct in research, and the necessary skills (offer negotiations, tenure, lab management, etc.) to transition to independence. Research: Anti-mAChR therapy is efficacious at reducing motor symptoms of some movement disorders, but severe side effects limit their utility. Our lab has made breakthroughs elucidating the roles of mAChRs, and found the M4 mAChR subtype diminishes DA release, signaling, and related motor behaviors. Additionally, M4 inhibition of DA signaling occurs tonically outside the striatum. This has led us to the model that when DA release or signaling is low, this allows M4 signaling to predominate, leading to motor dysfunction, and has led to our broad hypothesis that M4 antagonists will reduce motor deficits in movement disorders. While M4 activity may be a critical modulator of DA and basal ganglia activity, providing similar efficacy to non-selective mAChRs without side effects, this has not been tested. In preliminary data, we report the discovery of novel tool compounds to directly test our hypothesis, demonstrate losing D1 DA receptor signaling diminishes basal ganglia activity and produces motor deficits, and M4 activity bi-directionally modulates motor deficits. In aim 1, using animal models predictive of anti-parkinsonian efficacy, we will test how, and through what ACh sources, M4 activity modulates motor deficits. In aim 2, we will use a model of loss of D1 DA receptor signaling linked to dystonia to test how diminished DA signaling, possibly allowing M4 signaling to predominate, effects basal ganglia output and signaling. In aim 3, we will test how and where in the basal ganglia dystonia linked loss of D1 DA receptor signaling leads to motor deficits, and how M4 modulates these behaviors.
|
0.922 |