Barshop Symposium on Aging 2017 Abstracts

s from the meeting are presented in this issue, and represent a variety of aging and agerelated studies. A large focus was on aging and neurodegeneration including a number of presentations on Alzheimer’s disease. Other topics included cardiomyopathy, frailty, metabolism, pharmaceutical intervention of aging, age-related epigenetic modification, and cancer and aging. This annual meeting is well-attended and provides a seclusive and rustic environment in the Texas Hill Country for small group presentations and extensive informal interactions and discussions on the very latest findings and current thinking in the causes and prevention of aging and age-related diseases. LDLR-related protein 1 increases cytokine sensitivity. Implications for recovery after brain damage Sadiya Ahmad, Pamela Reed, Shane Sprague, Naomi L. Sayre University of Texas Health Science Center at San Antonio (UTHSCSA), TX Patients that express the Apolipoprotein E4 are predisposed to a poor long-term outcome after stroke. Explanations for this increased risk are not yet elucidated. This study aims to test one possible mechanism by which ApoE4 contributes to cognitive decline after stroke. Here, we examine the effect of a major ApoE4 receptor, low-density lipoprotein receptor related protein 1 (LRP1) on sensitivity to stress in astrocytes. LRP1 can promiscuously bind and move several extracellular ligands and plasma membrane proteins into the endocytic system. Notably, LRP1 was previously found to remove the TNF receptor (TNFR1) from the plasma membrane, although this has not been shown in astrocytes. We propose that a similar mechanism occurs in the central nervous system to attenuate inflammatory response after stroke. LRP1 binds and clears ApoE4 from the extracellular space via receptor-mediated endocytosis. However, previous studies have shown that the ApoE4, compared to other ApoE isoforms, slows the trafficking and recycling of endocytic LDL receptors. We propose that ApoE4 similarly inhibits LRP1 trafficking, and hypothesize that ApoE4 inhibits the ability of LRP1 to remove TNFR1 from the plasma membrane. This is expected to increase cytokine sensitivity, which would result in worse outcome after stroke and with aging. We investigated the effect of LRP1 on astrocyte TNFα signaling and response in immortalized ApoE null mouse astrocytes subjected to lentiviral-mediated knockdown ofLRP1. The astrocyte response to TNFα stimulation was tested in a concentration dependent manner using Western blotting of NFkB pathway components, which are the downstream mediators of TNFα signaling. We also tested astrocyte viability after prolonged TNFα stimulation using Alamar Blue reagent. We found that LRP1 deficient cells have increased phosphorylation of NFkB upon TNFα stimulation, and that loss of LRP1 resulted in significant loss of astrocyte viability after prolonged stimulation. Altogether, our results indicate that loss of LRP1 renders astrocytes more sensitive to TNFα. Future experiments will focus on treating astrocytes ApoE4 to determine if detrimental effects are exerted through LRP1, as well as testing the influence of LRP1 on recovery after middle cerebral artery occlusion in mice. *Correspondence to: Sadiya Ahmad, UTHSCSA, TX, USA. Email: ahmedsn@uthscsa.edu Elucidating the role of ALCAT-1 in dilated cardiomyopathy John-Paul Andersen Barshop Institute, UTHSCSA, TX Dilated cardiomyopathy (DCM) is a disease characterized by an abnormally large and weakened left ventricle which impairs the heart’s ability to pump blood. Due to its high mortality rate and high prevalence, DCM has been extensively researched and studied with a variety PATHOBIOLOGY OF AGING & AGE-RELATED DISEASES 2018, VOL. 8, 1444939 https://doi.org/10.1080/20010001.2018.1444939 © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. of treatment and symptom management options available. However, despite the many advances in the field, most cases are classified as idiopathic and most individuals die within two years of diagnosis. What has yet to be elucidated as a possible contributor to DCM is pathological cardiolipin remodeling. A major indicator that points to pathological cardiolipin remodeling being a primary contributor to DCM is the rare, x-linked genetic disorder Barth Syndrome. In this disease, individuals have a mutated tafazzin gene which causes a decrease in the predominant healthy species of cardiolipin known as tetralinoleoyl cardiolipin. Tetralinoleoyl cardiolipin has been shown to be drastically decreased in rodent models of heart disease as well as in humans with cardiomyopathy. Through investigating the role of cardiolipin remodeling on DCM and altering which cardiolipin species are present, it may open up novel treatment options for the disease and help provide greater insight into the cause of DCM. *Correspondence to: John-Paul Andersen, UTHSCSA, TX, USA. Email: andersenj@uthscsa.edu Evaluation of Long-Term Hippocampal NF-κB Suppression on Murine Behavior and Tau Protein Expression Eric Baeuerle, Miranda Orr, Ning Zhang, JosephM. Valentine, Hanyu Liang, You Zhou, Nicolas Musi Barshop Institute, UTHSCSA, TX Tau proteins are most well known for their role in neurodegenerative diseases such as Alzheimer’s disease. Physiologic tau regulates and stabilize microtubules within neuronal axons. Abnormal tau hyperphosphorylation leads to disruption of microtubule stabilization and subsequent tau aggregation, which can lead to neurodegeneration and dementia seen in Alzheimer’s disease. Although inflammation is known to be a major contributor to Alzheimer’s disease progression, its association with tau protein expression and regulation has not been significantly examined. Prior work by our research group has shown that inhibition of the transcription factor NF-ĸB, which directly regulates the expression of numerous inflammatory cytokines, increases tau protein expression in neuronal cells. In our ongoing studies, we are examining whether NFĸB regulates tau in vivo using stereotaxic delivery of AAV-IĸBα super repressor or AAV-GFP targeted to young mouse hippocampal neurons. After long-term suppression of hippocampal NF-ĸB, cognition and behavior were evaluated in a blinded manner using assays including open field, novel object recognition, Morris water maze, and contextual fear. Significant differences were observed between NF-ĸB suppressed and control groups in behavioral analysis. Whole brain and hippocampal tissue were collected for immunofluorescence, protein and RNA evaluation of NF-ĸB suppression, tau protein expression and regulation, and other associated markers of neuro inflammation. Future experiments will investigate hippocampalspecific upregulation of NF-ĸB-associated inflammation. The results of this work will help elucidate novel mechanisms of tau protein regulation and provide understanding of the role of inflammation and tau in the initial pathogenesis of Alzheimer’s disease. *Correspondence to: Eric Baeuerle, UTHSCSA, TX, USA. Email: baeuerle@livemail.uthscsa.edu Previous midlife estradiol treatment results in increased nuclear erα expression in the hippocampus of aging ovariectomized rats Nina E. Baumgartner, Katelyn L. Black, Jill M. Daniel Neuroscience Program; Brain Institute; Department of Psychology Tulane University Work from our lab has demonstrated that previous midlife estradiol treatment improves memory in ovariectomized female rats months after hormone exposure has ended. Furthermore, midlife estradiol exposure results in lasting increases in levels of estrogen receptor alpha (ERα) in the hippocampus, an effect that mediates the memory enhancements. Traditionally, ERα acts as a nuclear receptor, initiating genomic effects including increased transcription of certain genes. More recently, ERs have been localized to the membrane. Activation of membrane ERα could result in non-genomic, rapid acting effects. The goal of the current work is to determine where ERα is localized following midlife estradiol treatment. Middle-aged rats were ovariectomized and implanted with hormone capsules containing either estradiol or vehicle. Forty days later, capsules were removed. One month after hormone treatment ended, rats were killed and hippocampi were dissected and processed for subcellular fractionation. Hippocampal lysate was homogenized and separated into cytosolic, membrane, and nuclear compartments using the protocol included with a commercially available kit. All samples (cytosolic, membrane, and nuclear) were further processed for western blotting for ERα. Previous estradiol treatment resulted in lasting increases of nuclear protein expression of ERα compared to vehicle-treated rats. There were only trace amounts of cytosolic ERα, regardless of hormone treatment. We found no differences in membrane ERα protein expression. Results demonstrate that in the aging female hippocampus, lasting increases in ERα protein expression followingmidlife estradiol treatment are due to increases in nuclear-localized ERα. 2 W. LADIGES