Christy S. Carter - US grants

This proposal is designed to examine the biological bases of a developmental change in latent inhibition (LI) of the classically conditioned eyelid response. Previous data from our lab suggests that conditioning emerges gradually between postnatal day 17 (PND17) and PND24 (Stanton, Freeman, & Skelton, 1992; Freeman, Spencer, Skelton, & Stanton, 1993). Recent work in infants in our lab makes it possible to look at not only the behavioral and the neurological development of eyelid conditioning in the rat which is known to be dependent on the cerebellum but to further extend this analysis to other brain structures, such as the hippocampus, and what their role might be in the modulation of higher order forms of learning, such as (LI), within this late developing learning system. In order to address these issues preliminary studies of LI have been carried out in our lab to begin to establish the ontogeny of this behavior. We have shown that while 20-day-old pups do not show latent inhibition, 24-and 32-day-old rats do. We propose to perform selective medial septal lesions and afterwards test pups on LI to see if this behavior is disrupted. The ontogeny of this behavior may reflect a developmental interaction between the hippocampus and cerebellum.

DESCRIPTION (provided by applicant): We propose to use a rodent model of age-related physical decline to conduct pre-clinical testing of two promising pharmacologic interventions with the potential to forestall frailty-associated physical decline, angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARE) and to study pathophysiologic changes postulated to play important roles in frailty. The current PA (FRAILTY IN OLD AGE: PATHOPHYSIOLOGY AND INTERVENTIONS:PAS-03-122) recommends the preclinical testing of promising interventions with the potential to forestall frailty-associated physical decline such as ACEi. Preliminary studies presented in this application suggest that ACEi use in aged rats attenuates age-related declines in physical performance and is associated with a reduction in total body fat mass. This is of great interest in the context of frailty given the growing body of evidence linking differences in fat mass and fat distribution to muscle function and physical decline. However, it is unclear how ACEi may contribute to declining performance or whether the effects seen with ACEi are mediated by the angiotensin receptor or other mechanisms. Long-term clinical trials in hypertensive persons using either ARBs, which only block the action of ANGII by antagonizing the AT1 receptor, or ACEi have shown that both treatments reduce the risk for the development of metabolic abnormalities in fat and muscle associated with type II diabetes. There is still some debate as to how each intervention affects these changes. Alterations in either pathway have profound metabolic consequences, most notably in conditions of hypertension, obesity and insulin resistance. One primary and two secondary aims will be addressed in this application: 1) Determine the effect of Enalapril and Losartan vs. saline control treatment on physical performance across a portion of the lifespan of male Brown Norway x F344 rats;2) Determine the time course of age-related changes and the effect of Enalapril vs. Losartan treatment on whole body insulin sensitivity and glucose tolerance and changes in adipose tissue and skeletal muscle physiology;3) relate these findings to declining physical performance. These data will lay the groundwork for characterizing the role of long-term ACEi and ARB treatment in reversing these changes, as well as provide preliminary data for planning randomized clinical trials in humans for the prevention of the age related decline in physical function.

SUMMARY The goal of the University of Florida (UF) Older Americans Independence Center (OAIC) Pilot and Exploratory Studies Core (PESC) is to help plan future independently supported studies that address the UF OAIC's overall research theme of mobility and prevention of disability in older Americans. To this end, the PESC solicits and selects promising innovative pilot, exploratory, and developmental studies and secure optimal infrastructure, environment, funding, expertise, and resources. Core leaders monitor study progress, help analyze and interpret results, and provide guidance in translating these pilot data into high-quality and original research study proposals that successfully compete for independent extramural funding. The provision of funds for pilot, exploratory, and developmental studies supports Junior Scholars in their efforts to develop research careers in aging. The PESC also allows accomplished investigators in aging to gather data that extend and broaden their focus. In this capacity, it encourages and facilitates experienced investigators traditionally working in other research fields, such as physiology, cancer, pain, sepsis, and cognitive function, to expand their research to include aging. This widens the pool of talent that we believe will contribute to advances in disability prevention through averting mobility loss. In this application we propose four pilot studies and one exploratory study that offer a wide variety of interdisciplinary approaches to address the OAIC research theme. As we have proven over the past several years, we are highly successful in translating findings from our pilot, exploratory, and development studies into extramurally funded grants (76% success rate), and also in supporting our Junior Scholars through the tenure and promotion process.

ABSTRACT Declining physical function and the onset of disability among older persons has a tremendous impact on the health and longevity of affected individuals and is a central contributor to rising healthcare costs. Therapeutic strategies for the preservation of physical function are currently limited. Preliminary evidence suggests that the renin-angiotensin system (RAS) is a promising target for the development of new therapeutics to prevent functional decline. However there is currently a lack of knowledge regarding the direct impact of a recently- discovered vasodilatory arm of the RAS which is modulated primarily by the actions of the bioactive agent angiotensin converting enzyme 2 (ACE2) to convert angiotensin I and II to angiotensin-(1-7). This project will address this gap in knowledge by evaluating the impact of directly administering ACE2 to older rats in the preservation of physical function. We hypothesize that direct pharmacologic activation of the ACE2 axis will attenuate functional declines in late life. We will address this hypothesis with three specific aims, which are to: 1) Demonstrate that systemic administration of ACE2 improves physical function among older Fischer 344 x Brown Norway (F344/BN) rats, 2) Demonstrate that ACE2 improves functional responses to physical exercise, and 3) Identify physiologic adaptations associated with functional responses to ACE2 administration both in isolation and in combination with exercise. ANTICIPATED IMPACT: We have designed this study so that it has potential to be swiftly translated to humans. This study will fill an important gap in knowledge while also providing important data for the subsequent design of human studies to test our central hypothesis. The study is significant in that it addresses several clinical and public health problems deemed significant by the NIH as well as an important gap in the scientific literature. Innovations in the project include the reverse translation of our prior work in this area, targeting of the RAS for health benefits other than the regulation of blood pressure, and methodological innovations in the delivery of the therapeutic compound and the use of matrix-assisted laser desorption ionization (MALDI) mass spectrometry to evaluate tissue-level adaptations to the interventions.

ABSTRACT ? This Alzheimer?s Disease (AD) Supplement application (NOT-AG-18-039) represents an extension of our currently funded R01AG054538 Ace2 As A Novel Therapeutic To Preserve Physical Function In Late Life in which we study the impact of modulating the renin-angiotensin system (RAS) on age-related declines in physical function. Here we propose to apply the same interventions used in the parent grant to the study of cognitive frailty and AD. Cognitive frailty (simultaneous physical frailty and cognitive impairment) represents an enormous clinical and public health challenge given the rapid aging of the worldwide population. Individuals presenting with cognitive frailty have an increased risk for AD and other dementias. AD itself is a progressive neurodegenerative disorder, with no effective method for treatment despite extensive research focused on the brain as the target organ. We propose an exciting paradigm shift: directing intervention to the gut microbiome as the target ?organ? to treat cognitive frailty symptoms and mitigate the progression of AD. We have developed an innovative intervention whereby an orally-delivered probiotic incorporates delivery of angiotensin (1-7) [Ang(1-7)] to the gut. Ang(1-7) is a key vasoprotective effector of the RAS and the enzyme responsible for its production, angiotensin converting enzyme 2 (ACE2), is abundant in the healthy gut. Importantly, recent data from human and rodent studies suggest that severity of AD is inversely correlated with circulating levels of Ang(1-7) and ACE-2. Here, we propose to address the hypothesis that the Ang(1-7)- expressing probiotic will improve cognition in aged F344/BN rats and two preclinical models of AD: the Tg344- AD rat and the hAPP,hBACE AD flies. Understanding the relationship between RAS, gut integrity, and cognitive function is a new frontier in aging and AD risk research. Preclinical rodent models are invaluable; however, Drosophila represents an ideal model as well: high throughput screening capabilities, low cost, fast reproduction and an easily manipulated microbiome. Enzymes regulating RAS, are present in Drosophila, and the fly ACE gene, AnCE, is inhibited by the same drugs that inhibit ACE in humans. A recent paper suggest that enteric infection exacerbates inflammation and neurodegeneration in a fly model of AD. However, the use of probiotics, whether genetically modified or otherwise, has yet to be studied using fly models of AD. Global Specific Aim: Orally-administered probiotic expressing Ang (1-7) will enhance gut integrity, reverse gut dysbiosis, reduce intestinal, systemic and tissue-specific inflammation, and improve cognitive function using validated, comparative models of aging and AD: a) F344/BN rat; b) Tg344AD rat; c) hAPP, hBACE AD fly.

Project Summary ? Research Development Core The overarching goal of the Research Development Core (RDC) of the UAB Nathan Shock Center (NSC) is to support impactful research in the basic biology of aging related to the NSC theme of ?Comparative Energetics and Aging.? We will achieve this goal by addressing the following specific aims. 1. Maintain a nationally competitive pilot award program focused on the comparative biology of and energetics and aging to: a. Support expertly reviewed pilot studies. b. Provide an avenue to support earlier-phase studies via an expedited ?exploratory studies? funding mechanism. c. Facilitate interactions between potential applicants and leaders of UAB NSC Research Cores. 2. Solicit applications locally and nationally through interaction with UAB partners and the NSC Coordinating Center, choose projects for funding, and monitor progress of projects: a. Oversee a rigorous review process for selection of funded projects. b. Monitor outcomes (publications and grants) of funded studies. 3. Support the education and development of junior investigators by: a. Developing and maintaining an interdisciplinary pool of scientific mentors committed to guiding junior investigators to independence in the field of the biology of aging. b. Organizing a journal club on Center-related topics; promoting nascent project meetings for brainstorming feedback, and networking; and offering a series of ?boot camp? sessions (i.e., F to K, K to R, etc.). c. Facilitate junior investigator development as well as collaboration with other NSCs via development of a mock study section meeting open to junior investigators across the NSC network. d. Support conduct of the nationally advertised annual UAB integrated aging symposium. The RDC will capitalize upon the UAB NSC Research Cores as well as established collaborations with entities on the UAB campus and throughout the nation ? including with other NSCs. The Core activities will support the continued development of outstanding science in the biology of energetics and aging with particular emphasis on developing the next generation of independent scientists.

Project Summary Aging of the human population has become the number one threat to human health globally as life expectancy is rising rapidly and because aging underlies nearly all major causes of death, disability, and degradation of the quality of later life. Hope for amelioration of this trend lies with the development of treatments that enhance and extend health. A major limitation on evaluating promising compounds for their senescence-inhibiting properties is the time it takes to perform lifespan studies in mice, the main preclinical animal model employed in biomedical research. Similarly, once compounds are ready for human testing, the time it takes to complete clinical trials will also become a bottleneck. In order to speed progress in the field then, it would be invaluable to develop a panel of short-term assays that could be administered to mice in early- to mid-life that would predict whether or not an intervention will extend healthspan in mice. The ability of an organism to recover from acute physical challenges or stresses is well-known to decline with age. If we define resilience as a quantitative metric which gauges the ability and speed of an organism to return to homeostasis after physical stress or challenge, then life- and health-extending interventions generally enhance resilience. The goal of the proposed research is to develop a standardized challenge or panel of challenges and their accompanying recovery metrics that will be informative about the healthspan impact of putative health-extending interventions when administered in early-to-mid life. The overarching hypothesis of the proposed research is that resilience assays can be developed that singly, or in combination, predict future life- and/or health-span. We propose to evaluate our overarching hypothesis purposely focusing on resilience assays with translational potential by performing the following specific aims (SAs). SA 1 will optimize resilience assay protocols, each consisting of an acute physical challenge and associated recovery metrics as to the best age and severity of challenge to use. SA 2 will determine whether the resilience assays optimized in specific aim 1 can identify the impact of known life- or health-span extension treatments. Three such treatments will be compared to untreated controls. These are: (a) dietary restriction (DR). This can be thought of as a positive control. To be informative, our resilience assays should predict longer life in both sexes; (b) rapamycin, our resilience assays should predict longer life in both sexes, but a greater effect in females; and (c) 17-?-estradiol. Our resilience assays should predict longer life in males only. SA 3 will evaluate the robustness of the most successful resilience assays identified in specific aim 2 across mouse genotypes. Because humans are so genetically and environmentally diverse, the generality of mouse assays should be maximized to the extent possible. Diverse mouse genotypes are available to access whether the assays developed in aim 2 are idiosyncratic to the original test genotype or robust as we would want for human trials.