2013 — 2017 |
Lapierre, Louis Rene |
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. |
Role of Lipl-4 in Lysosomal Lipolysis and Aging @ Sanford Burnham Prebys Medical Discovery Institute
DESCRIPTION (provided by applicant): Dysfunctions in the utophagy/lysosomal pathway are pathologically significant in the development of age-related diseases, such as neurodegeneration. In C. elegans, several longevity models rely on increased autophagy for lifespan extension, suggesting a critical role for autophagy in aging. Animals can also enjoy longer lifespan when the nutrient-sensor TOR, a negative regulator of autophagy, is inhibited. Nonetheless, how autophagy mediates its beneficial effects is poorly understood. We recently reported that autophagy could be induced by over-expressing the putative lysosomal lipase LIPL-4, which resulted in a significant lifespan extension, enhanced lipolysis and altered TOR signaling, suggesting a link between lipid metabolism, autophagy and aging. LIPL-4 displays strong homology with human lysosomal acid lipase (LAL), a key enzyme in the hydrolysis of cholesterol via autophagy. Notably, impaired LAL-mediated cholesterol processing has been linked to the development of Alzheimer's disease. My new results show that over-expressing LIPL-4 ameliorates A¿ toxicity in a C. elegans model of Alzheimer's disease. Therefore, this proposal will test the hypothesis that LIPL-4, similar to LAL, mediates lysosomal lipid hydrolysis and will aim to elucidate how LIPL-4 modulates autophagy and mitigates A¿ toxicity. In Aim 1, I will confirm the intracellular site of action of LIPL-4 and determine its relationship to TOR signaling. In Aim 2, I will test whether LIPL-4 and LAL are functionally interchangeable in C. elegans. The mechanism of action by which LIPL-4 induces autophagy and modulates aging will also be elucidated. In Aim 3, I will investigate how LIPL-4 mediates a delay in the onset of Alzheimer's disease in C. elegans. I will also perform a high-throughput screen (HTS) to discover novel and specific candidate that activates LAL-mediated lipolysis, as a strategy against neurodegeneration. By determining the role of lysosomal lipolysis in aging, my proposal will provide a basis on which novel drugs can be discovered to prevent Alzheimer's disease. The 2-year postdoctoral K99 phase will consist in the characterization of the role of LIPL-4 in lysosomal function, lipid metabolism and aging. Cell-based assay reporter systems compatible with HTS will be used to find novel drugs to enhance LAL expression. The 3-year independent R00 phase will serve to further understand the role of LIPL-4 in lysosomal lipolysis, lipid signaling and aging and expand into studies on lipid dynamics, metabolism and proteostasis. Lead candidate activators of LAL will be validated using Alzheimer's disease model in C. elegans and cell culture models. This proposal includes cutting-edge approaches, such as proteomic analyses, CARS microscopy and HTS combined with the innovative use of disease models in C. elegans. In summary, the K99/R00 grant represents a unique opportunity for me to learn new technologies and develop my professional skills to successfully transition into an independent scientist in aging research.
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2016 — 2020 |
Lapierre, Louis Rene |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Regulation of the Transcription Factor Hlh-30/Tfeb in Aging
PROJECT SUMMARY/ABSTRACT Autophagy is a cellular recycling process with critical roles in aging and age-related diseases. Autophagy was originally described as a process mainly regulated at the post-translational level, but a role for transcriptional regulation has recently started to emerge. The relatively new concept of transcriptional regulation of the autophagy process provides an important new entry point toward developing therapies against age-related diseases. Recent studies in mammals have uncovered that the helix-loop-helix transcription factor EB (TFEB) is a central regulator of autophagy. We have reported that the C. elegans HLH-30 protein is a functional ortholog of TFEB and plays a broad role in C. elegans lifespan determination (Lapierre et al., Nature Communications, 2013). Specifically, we have found that HLH-30 is required for the lifespan extension observed in six independent longevity models, all of which are also known to be dependent on autophagy. Notably, HLH-30 is localized in the nucleus of intestinal cells in all of these long-lived mutants. Importantly, we have found TFEB to be similarly regulated in a mammalian longevity model suggesting that the longevity function of TFEB is also conserved. Therefore, we hypothesize that TFEB is a central player that modulates aging, at least in part by coordinating autophagic flux and, as such, represents an attractive longevity factor to molecularly understand in order to design approaches to promote healthspan and prevent aging. To address this hypothesis, we propose to use a combination of cutting-edge genetics and biochemical approaches to understand the spatial- and nuclear requirements for HLH-30 function in C. elegans lifespan (Aim 1); to address if downstream target genes besides those identified to function in autophagy are critical for longevity (Aim 2); and, finally, to identify genetic and pharmacological regulators of autophagy and HLH- 30/TFEB function (Aim 3). These studies are significant as they are the first to identify novel genetic regulators and post-translational modifications of HLH-30/TFEB in an unbiased fashion, and they will generate important information for future analysis of mammalian TFEB, a central regulator of autophagy as well as metabolism, in organismal aging. Furthermore, our studies are innovative because we employ C. elegans and mammalian cells in parallel to rapidly identify novel, conserved genes with roles in aging and to develop pharmacological solutions to enhance autophagy in order to prevent age-related diseases.
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2020 — 2021 |
Lapierre, Louis Rene |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Investigating Nucleo-Cytoplasmic Partitioning in Alzheimer's Disease and Aging
PROJECT SUMMARY/ABSTRACT Nucleo-cytoplasmic partitioning of proteins is an emerging intracellular process with crucial roles in Alzheimer?s disease and aging. Karyopherins mediate proper partitioning by transporting proteins across the nuclear pore. Pharmacological modulation of karyopherins provides a new approach for therapies against Alzheimer?s disease. Recent studies in model organisms and mammalian cells have uncovered that several neurodegenerative diseases display dysfunctional nucleo-cytoplasmic protein partitioning. We have reported that the conserved karyopherin XPO1 accelerates aging by promoting the nuclear export of longevity-associated transcription factors, thereby preventing the maintenance of proteostatic mechanisms. Specifically, we showed that inhibiting XPO1 leads to lifespan extensions and results in enhanced proteostasis across phyla, in part via the autophagy- lysosomal pathway. Levels of XPO1 are reduced in long-lived animals and our recent data suggest that XPO1-mediated lifespan modulation relies on fundamental changes in transcriptome and proteome partitioning as well as nucleoli re-organization, which results in altered ribosomal biogenesis. Thus, we hypothesize that XPO1 coordinately modulates the nucleo-cytoplasmic partitioning of proteins and nucleoli formation, thereby regulating compartment-specific protein functions, ribosomal biogenesis, active mRNA translation and consequently lifespan. To address this hypothesis, we propose to conduct a global characterization of protein partitioning and specification and its impact on proteostasis and aging. We will combine cutting- edge genetics and biochemical approaches in C. elegans and mammalian cells to characterize the nucleo-cytoplasmic partitioning of proteins during aging (Aim 1) and, ultimately, to uncover new modulators of nucleolar function with potential benefits against Alzheimer?s disease (Aim 2). These proposed studies are significant as they address an important question in aging related to the role and regulation of nucleo-cytoplasmic partitioning and nucleoli function during organism aging. Our approaches are innovative since we utilize C. elegans and mammalian cells in parallel to quickly identify specific protein translation and partitioning of proteins with roles in aging and to uncover pharmacological strategies to modulate nucleolar and ribosomal dynamics and preventing Alzheimer?s disease.
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