Anthony J. Molina - US grants

? DESCRIPTION (provided by applicant): Older adults exhibit poor recovery and are at high risk for rehospitalization after acute heart failure. Current rehabilitation and clinical management strategies have shown only modest benefits because the mechanisms underlying poor outcomes remain under recognized and therefore unmitigated. The proposed study will address this critical knowledge gap by examining the role of systemic mitochondrial bioenergetic capacity as a fundamental factor underlying poor physical function in hospitalized acute decompensated heart failure, the success of rehabilitation, and the prognosis of patients following hospitalization. This will be accomplished in a highly translational and cost-effective manner as an ancillary study to REHAB-HF (R01AG045551; PI: Kitzman), a multi-center clinical trial funded by the NIA that tests the hypothesis that impaired physical function underlies adverse outcomes in older hospitalized ADHF patients and employs a novel rehabilitation program that targets multiple domains of physical function for 12 weeks beginning during hospitalization. The results of REHAB-HF can impact clinical practice; however, its outcomes do not directly address potential mechanisms of action. Mitochondrial function is likely candidate for mediating physiological decline in REHAB-HF participants, because these organelles are sensitive to a myriad of intrinsic and extrinsic factors related to aging, physical function, heart failure, and hospitalization. Mitochondrial dysfunction across multiple tissues has been implicated in physiological decline associated with heart failure and is thought to be mediated by circulating factors that affect systemic bioenergetic capacity. Therefore, we propose that respirometric profiling of circulating cells can be used to report on systemic bioenergetic decline in heart failure patients and will be associated with physical function and long term outcomes - including rehospitalization rate. We will determine whether the REHAB-HF rehabilitation program increases bioenergetic capacity, compared to control, thereby improving functional outcomes. Bioenergetic profiling of multiple blood cell populations will enable us to identify the specific cell types and bioenergetic parameters, or patterns comprised of multiple variables, that are most closely associated with REHAB-HF outcomes such as physical function and quality of life. We will also determine the ability of blood cells to report on systemic bioenergetic decline y examining relationships with mitochondrial function measured in skeletal muscle. Successful strategies for mitigating poor physical function and improving long-term outcomes rely on the identification of mechanisms that contribute to the vulnerability of patients after discharge. Bioenergetic profiling may enable the identification of patients in need of more intensive management and targeted rehabilitation. The advancement of blood-based bioenergetic profiling will enhance the use of this promising test in future trials, and potentially, in the cliical care of older patients with the wide range of chronic medical conditions associated with physical disability and poor clinical outcomes.

7. Project Summary/Abstract In Alzheimer's disease (AD), irreversible neurological damage takes place years before the onset of clinical symptoms. Therefore, it is recognized that the development of AD dementia treatment and prevention strategies relies on the early detection of presymptomatic pathology. Previous studies demonstrate that mitochondrial dysfunction plays a key role in the pathophysiology of AD and precedes the formation of plaques and tangles that are hallmarks of this disease. The premise of this study is based on the unique sensitivity of the brain to systemic bioenergetic decline due to its exceptionally high metabolic demand. We hypothesize that bioenergetic capacity is related to early AD pathology and that bioenergetic decline is associated with the long term progression and severity of this disease. Recent work by our group and others demonstrate that blood- based bioenergetic profiling, utilizing cellular respirometry, provides a reliable measure of systemic mitochondrial function. The proposed study will determine whether blood cell bioenergetics is related to AD risk, pathology, cognitive performance, and changes in these parameters over time. Our long term goal is to develop a minimally invasive screening tool that can be used in a clinic/community setting to identify candidates for more intensive diagnostic testing, such as CSF biomarker analysis and brain imaging. This project will be completed in an efficient and cost-effective manner by leveraging resources provided by the NIA-funded Wake Forest Alzheimer' Disease Center Clinical Core (ADCCC). Participants in the ADCCC represent a spectrum of AD risk and disease progression and are being extensively characterized for AD pathologies at baseline and 3 year follow ups. Our preliminary data from ADCCC participants indicate that bioenergetic capacity, measured in blood cells, is lower in participants with mild cognitive impairment. Moreover, our data suggest that bioenergetic deficits are already apparent in cognitively normal participants at high risk for AD. The aims of the proposed study are: 1) To determine bioenergetic profiles most strongly associated with AD risk and reporters of AD pathology (cognitive performance, CSF A?42/tau, hippocampal volume, brain amyloid, and cerebral glucose metabolism); 2) To determine the changes in bioenergetic profiles related to the 3 year progression of cognitive decline and reporters of AD pathology; and, 3) To determine the relationships of mitochondrial content and inflammation with bioenergetic capacity, and reporters of AD pathology at baseline and at follow-up. A central goal of the proposed study is to determine the specific bioenergetic parameters that are most closely associated with AD risk and pathology. Therefore, in addition to convention analytical approaches, we will employ state of the art Machine Learning analyses to identify individual parameters or multivariate signatures that are most closely associated with AD risk and pathology. Completion of this project can impact the detection of presymptomatic AD, provide insights into mechanisms underlying bioenergetic decline associated with AD, and broadly advance translational bioenergetics research.

7. Project Summary/Abstract Mitochondrial dysfunction is linked to the onset and progression of Alzheimer's disease (AD), including the deposition of plaques and neurofibrillary tangles that are hallmarks of this disease. The premise of this study is derived from multiple lines of evidence indicating that impairments in neural as well as peripheral bioenergetics are related to cognitive decline and may contribute to AD pathology. Despite mounting evidence implicating mitochondria as promising targets for AD prevention and therapy, the mechanisms underlying bioenergetic decline observed across tissues remain unclear. Seminal studies have demonstrated that circulating factors play a key role in aging and multiple age-related disorders. We propose that circulating, blood-borne, factors mediate systemic bioenergetic decline in AD and its prodrome, mild cognitive impairment (MCI). Our preliminary studies demonstrate that non-cellular components, in human serum, can mediate mitochondrial function in a manner consistent with observations linking cognitive impairment and low bioenergetic capacity. The aims of this proposal are to identify mediators of systemic bioenergetic capacity 1) across stages of AD and the 3 year progression of dementia and pathology; and 2) in response to exercise, a promising AD intervention widely recognized to have systemic bioenergetic benefits. Circulating factors including peptides, lipid metabolites, RNAs, cytokines; and more recently, exosomes, have been suggested to be involved in various age-related disorders. In order to address the complexities of this line of research, we have developed a novel systematic approach for examining human serum, in-vitro, to identify the components responsible for mediating bioenergetic capacity across multiple cell types. We will utilize serum fractionation / subfractionation and reiterative respirometric profiling of neurons and peripheral cells to determine which serum components (exosomes, free proteins, and/or free metabolites) are capable of mediating differences in bioenergetic capacity associated with AD status, progression, and response to intervention. Individual serum components will be analyzed by RNAseq, proteomics, and metabolomics to identify circulating factors that are differentially expressed based on AD status, progression, and response to intervention. This project will be completed in a highly cost-effective and efficient manner by utilizing samples from ongoing studies at our NIH funded WFSM AD Core Center (ADCC) and AD Cooperative Study (ADCS) sites across the country. The results of this study will provide key mechanistic insights into mediators of systemic AD pathology and could shift the focus of AD prevention and therapy to include strategies targeting mitochondrial bioenergetics and its regulators. The robust framework of this study will generate an extensive repository of bioenergetic, proteomic, metabolomic, and RNAseq data linked to biological specimens and clinical outcomes that will be available to the broader research community to support future research.

The objective of this study is to develop and validate biomarkers that reflect mechanisms of biological aging. At least five pharmacologic compounds approved for human use extend health span and life span in rodent models. Parallel approaches in humans would require studies lasting 40+ years and are infeasible. Rather, the field needs reliable human biomarkers that indicate beneficial (or adverse) effects of an intervention on aging-related pathways over shorter time periods. Epigenomics and resultant transcriptomic changes may unite mechanisms of biological aging implicated in animal studies and unravel novel pathways. In a genome- wide analysis of monocyte samples in 1,200 persons (aged 55-94 years) from the Multi-Ethnic Study of Atherosclerosis (MESA), we identified 1,794 age-associated methylation sites and 2,704 age-associated transcripts, which over-represented several networks, including mitochondrial bioenergetics and autophagy. We further demonstrated associations of these gene networks with aging-related diseases independent of age. In addition to omic profiles, functional phenotyping may provide further advantages as biomarkers of the aging process. For example, our studies in older adults indicate the bioenergetic capacity of peripheral blood mononuclear cells is positively associated with physical function measures even when controlling for age. We predict that these epigenetic, transcriptomic, and functional markers will be associated with the development of aging-related comorbidities and are responsive to caloric restriction. We propose to utilize existing longitudinal assessments of monocyte epigenetic/transcriptomic profiles and age-related health outcomes from 1,800 middle-aged and older adults (55-94 years) in the MESA study. Leveraging an ongoing randomized clinical trial (VEGGIE) of caloric restriction in 200 adults (40-70 years), we also propose to add skeletal muscle biopsy (N=80). The specific aims are: 1) to determine whether aging-related monocyte transcriptomic/epigenomic pathways individually or in combination predict changes in aging-related diseases over an 8-year follow up (N=1,800); and 2) To determine whether caloric restriction shifts aging-related monocyte transcriptomic/epigenomic pathways (N=200) and bioenergetic measures in circulating cells and skeletal muscle (N=80) towards a younger pattern and whether these changes individually or in combination correlate with changes in aging-related metabolic, physical and cognitive health outcomes. The proposed study will generate a panel of biomarkers reflecting a comprehensive battery of aging pathways by integrating transcriptomic and epigenomic profiles with bioenergetics in circulation and skeletal muscle, from an existing longitudinal cohort study and an ongoing clinical trial of caloric restriction, to efficiently and cost-effectively validate potential biomarkers through multiple convergent strategies.

7. Project Summary/Abstract Alterations in exosome secretion and content have been linked to Alzheimer's disease (AD). These nanovesicles are abundant in circulation and are being examined as promising blood-based biomarkers of disease. Importantly, exosomes derived from AD patients and animal models have been shown to carry pathogenic cargo and can contribute to the spread of neuronal dysfunction. Our preliminary data provide striking new evidence that key features of early AD pathophysiology, such as mitochondrial dysfunction and altered cellular metabolism, can be mediated by exosomes derived from AD patients. The proposed study will test the hypothesis that circulating exosomes mediate systemic changes in cellular metabolism associated with early stages of AD and contribute to the spread of AD pathology over the long-term progression of disease. The primary goals of this proposal are: 1) to characterize total, neuron-derived, and astrocyte-derive exosomes across stages of AD and over the 3 year progression of disease using integrated omics analysis; and 2) to examine the mechanisms by which exosomes affect cellular metabolism, AD pathology, and cognitive decline using complementary in vitro, ex vivo, and in vivo approaches. The proposed study capitalizes on a unique and timely opportunity to utilize plasma samples from an ongoing NIA-funded study of participants in the Wake Forest Alzheimer' Disease Center Clinical Core. With the costs for sample collections, key clinical measures, and human bioenergetic profiling covered by existing funding, we have a valuable opportunity to advance our understanding of how exosome-mediated intercellular communication is involved in the onset and spread of AD pathophysiology. The results of this study will provide new mechanistic insights into mediators of AD pathology and could shift the focus of AD prevention and therapy to include strategies targeting the detrimental effects of exosome mediated intercellular signaling and systemic bioenergetic decline. The robust framework of this study will support future research efforts by advancing novel in vitro and in vivo experimental approaches, and by generating a comprehensive exosome repository and database linked to an ongoing longitudinal cohort study of AD.