Andrew A. Pieper - US grants

inositol phosphates; receptor; physical chemical interaction; cyclic AMP; protein kinase A; phosphorylation; dopamine receptor; second messengers; calcium flux; receptor expression; molecular biology; mental disorders; immunoprecipitation; western blottings; laboratory rat; laboratory rabbit;

DESCRIPTION (provided by applicant): Due to a profound lack of treatment options for neuropsychiatric disease, there is a critical need to facilitate the translation of findings from basic neuroscience to new treatments for patients. Through an in vivo screen conducted in living mice, a biologically active aminopropyl carbazole, designated P7C3, was identified with potent proneurogenic and neuroprotective properties. A multi-year structure-activity-relationship study on this chemical scaffold has enabled optimization of potency and efficacy, while minimizing real and perceived liabilities for drug development. The P7C3 class of molecules stabilizes mitochondrial membrane potential and protects neurons from cell death. Significant protective efficacy of P7C3 and it's more potent and efficacious variant, P7C3A20, has now been demonstrated in animal models of aging, Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. A new challenge is to provide additional evidence that these compounds could be beneficial to the human brain. An initial step to meet this challenge is to demonstrate that the most effective of these compounds (P7C3A20) has a proneurogenic and/or protective effect in the nonhuman primate brain. Human brain disorders are defined by changes in complex human behaviors (i.e., cognition, emotion etc.), and evaluation of the therapeutic effects of neuroprotective compounds may ultimately benefit from studies in animal species that are more closely related to humans than are mice. Moreover, the literature is replete with examples of drugs that work well in mice but are not therapeutically beneficial in humans. Rhesus macaques (Macaca mulatta) provide a useful proxy for efficacy in the human, as they demonstrate many features of human physiology, anatomy and behavior. Rhesus monkeys are thus ideal for studying a variety of complex human brain disorders. However, before we can begin to explore the therapeutic potential of the P7C3 class of molecules in sophisticated nonhuman primate diseases models, we must first establish a neuroprotective role for the P7C3 class of molecules in the primate brain. Here, we propose quantification of nonhuman primate hippocampal neurogenesis as a function of exposure to P7C3A20, in order to provide a rapid, cost effective and straightforward means of assessing efficacy of neuroprotection in the rhesus monkey. Preclinical proof of principle in a nonhuman primate could provide an opportunity to translate basic science into a new therapeutic approach for patients suffering from both neuropsychiatric and neurodegenerative diseases involving diminished hippocampal neurogenesis and/or broader neurodegeneration. PUBLIC HEALTH RELEVANCE: This project is designed to provide additional support for a novel class of molecules demonstrating neuroprotective effects in rodent models. Preclinical proof of principle in a nonhuman primate model could provide an opportunity to translate basic science into a new therapeutic approach for patients suffering from both neuropsychiatric and neurodegenerative diseases involving diminished hippocampal neurogenesis and/or broader neurodegeneration.

PROJECT SUMMARY Stroke is the most common contributor to disability in the United States (US), with over 800,000 people affected each year. In addition to treatment with intravenous recombinant tissue plasminogen activator (rtPA), endovascular mechanical thrombectomy (MT) is now the standard of care for patients with a stroke due to proximal arterial occlusion. Unlike rtPA, however, MT is available at only a limited number of tertiary centers, with stringent time-dependent effect tied to viable ischemic penumbra. As a result, many patients in rural or congested areas need rapid transfer to a tertiary center capable of delivering MT while undergoing intravenous rtPA infusion by Helicopter Emergency Medical Services (HEMS). There is thus a significant unmet need to develop neuroprotective interventions that promote patient eligibility for MT after HEMS. A significant barrier to progress, however, is concern of whether current animal stroke models adequately translate the effect of neuroprotective interventions on an ischemic brain receiving rtPA during HEMS evacuation. That concern is justified by the uniqueness of the HEMS physiological environment, with multiple physical factors such as hypobaric changes, low frequency vibration, three-axis acceleration, and extreme noise. These physical factors may affect ischemic brain receiving rtPA in multiple and opposing ways, such as decreased oxygenation in the penumbra, enhanced or decreased clot lytic effect of rtPA, increased blood-brain-barrier (BBB) permeability and raised blood pressure. There is therefore a critical need to clarify and quantify the effect of these factors on neurological outcomes, in order to ensure that preclinical animal stroke models rigorously account for the unique physiological HEMS environment. The objective of this proposal is to measure the potential effect of HEMS physical factors on ischemic brain with respect to rtPA-reperfusion, infarct size and BBB permeability. We will use a novel experimental approach that combines a traditional stroke animal model with actual helicopter transport and vibration simulation. We have a multidisciplinary team of animal researchers and engineering, with access to a dedicated Mi2 helicopter that has been adapted and certified as a flying research platform. Mice/rats undergoing an embolic stroke will be randomized to receive the rtPA infusion simultaneously either in an actual helicopter flight, vibration simulator, or under ground-based conditions. Outcome measures will include measures of rtPA activity, cerebral blood flow, infarction size and hemorrhagic transformation, and BBB permeability at 48h and sensorimotor neurological outcome measures at 7 days, all of which will be correlated with helicopter-generated factors such as vibration, acceleration and altitude. We anticipate that this work will meaningfully transform the field of acute stroke care by understanding the overall effect of HEMS in the ischemic brain. This will lead to the establishment of adequate animal models to facilitate intervention research to improve the outcomes of patients during this critical early setting.