Project description:Studies of long-lived individuals have revealed few genetic mechanisms for protection against age-associated disease. Therefore, we pursued genome sequencing of a related phenotype-healthy aging-to understand the genetics of disease-free aging without medical intervention. In contrast with studies of exceptional longevity, usually focused on centenarians, healthy aging is not associated with known longevity variants, but is associated with reduced genetic susceptibility to Alzheimer and coronary artery disease. Additionally, healthy aging is not associated with a decreased rate of rare pathogenic variants, potentially indicating the presence of disease-resistance factors. In keeping with this possibility, we identify suggestive common and rare variant genetic associations implying that protection against cognitive decline is a genetic component of healthy aging. These findings, based on a relatively small cohort, require independent replication. Overall, our results suggest healthy aging is an overlapping but distinct phenotype from exceptional longevity that may be enriched with disease-protective genetic factors.
Project description:Recent findings suggest that the human APOE epsilon 4 allele protects against non-alcoholic fatty liver disease, while APOE epsilon 3 promotes hepatic steatosis and steatohepatitis. We performed an untargeted proteome analysis of the liver and identified a great number of proteins differently expressed in obese APOE3 and APOE4 mice. The majority of the proteins up-regulated in APOE3 can be grouped to inflammation and damage-associated response, cytoskeleton and lipid storage. In contrast, those proteins that are up-regulated in APOE4 can be related to intermediate filament modifications, biotransformation and amino acid metabolism. Results of the targeted quantitative RT-PCR and Western blot experiments contribute to the overall finding that APOE3 promotes hepatic steatosis, inflammatory- and damage-associated response signaling and fibrosis in the liver of obese mice. One of the proteins that were up-regulated in obese as well as lean APOE4 compared to APOE3 mice is parvulin 14 (Pin4). Up-regulation of parvulin 14 may be involved in the protection against fatty liver disease evident in the presence of APOE4.
Project description:In 12-month-old APOE targeted-replacement mice, we report that overall differences in gene expression were the most prominent when comparing the protective APOE2 to the other two alleles, with fewer differences found when comparing the risk-neutral APOE3 and disease-promoting APOE4 alleles. When compared with either APOE3 or APOE4, differential expression of genes within the endosomal pathways is a prominent feature of APOE2 expression in the brain. We hypothesized that the protective effects of APOE2 are mediated through the endosomal pathway during aging. In contrast to Alzheimer’s disease and APOE4 models, we detected normal morphology and abundance of early endosomes within cortical neurons of APOE2 targeted-replacement mice during aging despite decreased rab5b recruitment to early endosomes. Similarly, the morphology and abundance of retromer-associated vesicles was normal in APOE2 mice, despite reduced recruitment of vesicle-associated VPS35. Significantly, we observed increased brain extracellular levels of endosome-derived exosomes in APOE2 compared with APOE3 mice during aging, indicative of an enhanced endosomal cargo clearance to the extracellular space that contributes to a homeostatic balance of endosomal functions. Our findings thus demonstrate that APOE2 effectively offsets endosomal pathway changes during aging to preserve its integrity by enhancing exosome biogenesis, mitigating age-driven endosomal dysfunction that contributes to Alzheimer’s disease risk.
Project description:<p>Lysosomes are key cellular organelles that metabolize extra- and intra-cellular substrates. Alterations in lysosomal metabolism are implicated in aging-associated metabolic and neurodegenerative diseases. However, how lysosomal metabolism actively coordinates the metabolic and nervous systems to regulate aging remains unclear. Here, we report a fat-to-neuron lipid signaling pathway induced by lysosomal metabolism and its longevity promoting role in <em>Caenorhabditis elegans</em>. We discovered that induced lysosomal lipolysis in peripheral fat storage tissue up-regulates the neuropeptide signaling pathway in the nervous system to promote longevity. This cell-non-autonomous regulation is mediated by a 47 specific polyunsaturated fatty acid, dihomo-gamma-linolenic acid (DGLA) and LBP-3 lipid chaperone protein transporting from the fat storage tissue to neurons. LBP-3 binds to DGLA, and acts through NHR-49 nuclear receptor and NLP-11 neuropeptide in neurons to extend lifespan. These results reveal lysosomes as a signaling hub to coordinate metabolism and aging, and lysosomal signaling mediated inter-tissue communication in promoting longevity.</p>
Project description:FoxO transcription factors promote longevity across taxa. How they do so is poorly understood. In the nematode Caenorhabditis elegans, the A- and F-isoforms of the FoxO transcription factor DAF-16 extend life span in the context of reduced DAF-2 insulin-like growth factor receptor (IGFR) signaling. To elucidate the mechanistic basis for DAF-16/FoxO-dependent life span extension, we performed an integrative analysis of isoform-specific daf-16/FoxO mutants. In contrast to previous studies suggesting that DAF-16F plays a more prominent role in life span control than DAF-16A, isoform-specific daf-16/FoxO mutant phenotypes and whole transcriptome profiling revealed a predominant role for DAF-16A over DAF-16F in life span control, stress resistance, and target gene regulation. Integration of these data sets enabled the prioritization of a subset of 92 DAF-16/FoxO target genes for functional interrogation. Among 29 genes tested, two DAF-16A-specific target genes significantly influenced longevity. Our discovery of new longevity genes underscores the efficacy of our integrative strategy while providing a general framework for identifying specific downstream gene regulatory events that contribute substantially to transcription factor functions. As FoxO transcription factors have conserved functions in promoting longevity and may be dysregulated in aging-related diseases, these findings promise to illuminate fundamental principles underlying aging in animals. Whole-transcriptome profiling of daf-16/FoxO isoform-specific deletion mutants in the long-lived daf-2(e1370) background. Included are daf-16 wild-type, daf-16 null mutation, daf-16a/f mutation, two independent daf-16a mutations, and daf-16f mutation. N2 wild-type controls are also included.
Project description:Calorie restriction is a major intervention consistently demonstrated to retard aging and delay age-associated diseases. A novel micronutrient blend, a putative calorie restriction mimetic, was developed based on a screening tool we previously described. Whole transcriptomic analysis was examined in brain cortex, skeletal muscle and heart in three groups of mice: old controls (30 months), old + calorie restriction and old + novel micronutrient blend. The micronutrient blend elicited transcriptomic changes in a manner similar to those in the calorie-restricted group and unique from those in the control group. Subgroup analysis revealed that nuclear hormone receptor, proteasome complex and angiotensinogen genes, all of which are known to be directly related to the aging process, were the most affected by the micronutrient blend and by calorie restriction. Thus, these three genes may be considered master regulators of the favorable effects of calorie restriction and of the micronutrient blend. Based on the calorie restriction mimetic effects on transcriptomics, it was hypothesized that the micronutrient blend would promotes longevity and vitality. To test this hypothesis, a functional analysis in C. Elegans was used to examine the effects of the micronutrient blend on longevity and biomarkers of vitality. Results indicate that feeding C. Elegans the micronutrient blend increased longevity as well as vitality. Further studies are required to confirm that the calorie restriction mimicking benefits described here are elicited by the micronutrient blend in humans.
Project description:Apolipoprotein E4 (APOE4) is the strongest genetic risk factor for late-onset Alzheimer’s disease (LOAD), leading to earlier age of clinical onset and exacerbating pathologies. There is a critical need to identify protective targets. Recently, a rare APOE variant, APOE3-R136S (Christchurch), was found to protect against early-onset AD in a PSEN1-E280A carrier. We sought to determine if the R136S mutation also protects against APOE4-driven effects in LOAD. We generated tauopathy mouse and human iPSC-derived neuron models carrying human APOE4 with the homozygous or heterozygous R136S mutation. We found that the homozygous R136S mutation rescued APOE4-driven Tau pathology, neurodegeneration, and neuroinflammation. The heterozygous R136S mutation partially protected against APOE4-driven neurodegeneration and neuroinflammation, but not Tau pathology. Single-nucleus RNA-sequencing revealed that the APOE4-R136S mutation increased disease-protective and diminished disease-associated cell populations in a gene dose-dependent manner. Thus, the APOE-R136S mutation protects against APOE4-driven AD pathologies, providing a target for therapeutic development against AD.
Project description:MV130 is an inactivated polybacterial mucosal vaccine that confers protection to patients against recurrent respiratory infections, including those of viral etiology. However, its mechanism of action remains poorly understood. Herein, we observe that intranasal prophylaxis with MV130 modulates the lung immune landscape and provides long term heterologous protection against viral respiratory infections in mice. Intranasal administration of MV130 provided protection against systemic candidiasis in wild-type and Rag1-deficient mice lacking functional lymphocytes, indicative of innate immune-mediated protection. Moreover, pharmacological inhibition of trained immunity with metformin abrogated the protection conferred by MV130 against Influenza A virus respiratory infection. MV130 induced reprogramming of mouse bone marrow progenitor cells and human monocytes, promoting an enhanced cytokine production that relied on metabolic and epigenetic shifts. Our results unveil that the mucosal a dministration of a fully inactivated bacterial vaccine provides protection against viral infections by a mechanism associated with the induction of trained immunity. This SuperSeries is composed of the SubSeries listed below.
Project description:Caloric restriction (CR) is the only non-genetic intervention to retard aging and increase longevity in a variety of species. It is important to understand the fundamental mechanism by which CR extends lifespan that remains elusive. Owing to well-established genomic tools and convenience of culture system, we used a single cell organism, Saccharomyces cerevisiae, to clarify the mechanisms of CR. In order to identify genes responsible for CR-mediated longevity, we performed microarray experiments across the longevity assurance time-points.
Project description:Caloric restriction (CR) is the only non-genetic intervention to retard aging and increase longevity in a variety of species. It is important to understand the fundamental mechanism by which CR extends lifespan that remains elusive. Owing to well-established genomic tools and convenience of culture system, we used a single cell organism, Saccharomyces cerevisiae, to clarify the mechanisms of CR. In order to identify genes responsible for CR-mediated longevity, we performed microarray experiments across the longevity assurance time-points. Since the CR-treated cells obtained the longevity potential around 12 hours after inoculation and the strength of potential gradually increased up to 48 hours, we concluded that the changes across these time-points must be a critical need for assurance of longevity by CR. For preparation of total RNA, yeast cells under control (2% glucose) and CR (0.5% glucose) conditions were harvested at 12h, 18h, 24h and 48h after inoculation. After total RNA extraction, we performed Affymetrix Yeast GeneChip 2.0 array for biological triplicate repeats according to the manufacturer's instructions.