A Genome-Wide Integrative Study of DNA Methylation, Gene Expression, and Later Life Hand Grip Strength

fat than men, which may contribute to sex-specific effects on knee extensor specific torque through differences in muscle fiber size and cross-bridge kinetics. In older humans, multiple chronic diseases and increased life expectancy impose a disproportionate socioeconomic burden. Dietary interventions are valuable strategies for promoting healthy aging. Caloric restriction (CR) without malnutrition is a robust intervention able to delay disease onset and increase survival in model organisms. However, the impracticability of chronic CR outweighs the potential long-term benefits in humans. Time-restricted feeding (TRF), i.e. the limitation in the timing of food intake without ne-cessarily reducing caloric intake, can protect against metabolic disorders through the synchronization of the circadian rhythm. This study compares whether limiting access to ad libitum (AL) food for a few hours per day mimics the bene-ficial effects of a CR diet. A large cohort of C57BL/6J female mice (n=250) was distributed into five feeding paradigms at midlife: AL, TRF for 8 hours, TRF for 4 hours, 20% CR and 20% CR fed twice a day (CRx2). Pathological analyses at death reveal a shift in fatal neoplasms toward an older age in TRF8 mice. AL mice had the highest prevalence of tumors (93%) and TRF4 had the lowest (77%). The highest tumor burden was observed in AL mice while CRx2 animals had the lowest number of neoplasms. Histiocytic sarcoma and lymphoma were the most represented malignancies, with CR mice exhibiting the highest rate of histiocytic sarcoma (75%) and the lowest rate of lymphoma (10%). These results indi-cate that time- and calorie-restricted feeding regimens can slow down malignant neoplasm progression and extend


TIME-RESTRICTED FEEDING AND CALORIC RESTRICTION IMPACT ON SPONTANEOUS NEOPLASMS IN FEMALE MICE
Annamaria Rudderow, Eleonora Duregon, Michel Bernier, and Rafael de Cabo, 1. National Institute on Aging, Bethesda, Maryland, United States In older humans, multiple chronic diseases and increased life expectancy impose a disproportionate socioeconomic burden.Dietary interventions are valuable strategies for promoting healthy aging.Caloric restriction (CR) without malnutrition is a robust intervention able to delay disease onset and increase survival in model organisms.However, the impracticability of chronic CR outweighs the potential long-term benefits in humans.Time-restricted feeding (TRF), i.e. the limitation in the timing of food intake without necessarily reducing caloric intake, can protect against metabolic disorders through the synchronization of the circadian rhythm.This study compares whether limiting access to ad libitum (AL) food for a few hours per day mimics the beneficial effects of a CR diet.A large cohort of C57BL/6J female mice (n=250) was distributed into five feeding paradigms at midlife: AL, TRF for 8 hours, TRF for 4 hours, 20% CR and 20% CR fed twice a day (CRx2).Pathological analyses at death reveal a shift in fatal neoplasms toward an older age in TRF8 mice.AL mice had the highest prevalence of tumors (93%) and TRF4 had the lowest (77%).The highest tumor burden was observed in AL mice while CRx2 animals had the lowest number of neoplasms.Histiocytic sarcoma and lymphoma were the most represented malignancies, with CR mice exhibiting the highest rate of histiocytic sarcoma (75%) and the lowest rate of lymphoma (10%).These results indicate that time-and calorie-restricted feeding regimens can slow down malignant neoplasm progression and extend health span in female mice, even when started in adulthood.

UNCOVERING THE SPECIFIC FUNCTIONS OF MIR-33 IN REGULATION OF FEEDING AND CARDIOMETABOLIC DISEASES LINKED TO AGING.
Nathan Price, 1 Xinbo Zhang, 1 Pablo Fernandez-Tussy, 1 Rafael de Cabo, 2 and Carlos Fernandez-Hernando, 1 1.Yale University,New Haven,Connecticut,United States,2. National Institute on Aging,Bethesda,Maryland,United States Heart disease and metabolic dysfunction are two of the most important age related health issues, and feeding behavior is a critical factor contributing to these conditions.miR-33 promotes the development of atherosclerosis, by impairing macrophage cholesterol efflux and reverse cholesterol transport.Specific disruption of the interaction between miR-33 and the cholesterol transporter ABCA1 protected mice from atherosclerosis in a manner similar to that observed with loss or inhibition of miR-33.However, miR-33 has also been shown to impact other cellular functions, including targeting numerous mRNAs related to bioenergetics and inflammatory response, that may also contribute to its effects on atherosclerosis.Moreover, characterization of miR-33 deficient animals has revealed a strong predisposition to the development of obesity and metabolic dysfunction.While this phenotype appears to be due to alterations in feeding behavior, it is not clear what organ or organs are primarily driving this effect or what functions of miR-33 may be responsible.To address these questions, we have generated conditional miR-33 knockout mice to selectively remove miR-33 from a number of key metabolic tissues.Using these unique mouse models, we have performed an extensive characterization of how miR-33 impacts the function of different metabolic tissues in both chow and high fat diet fed mice, and assessed what impact this has on regulation of metabolic homeostasis and atherosclerosis.This work will improve our understanding of the mechanisms regulating feeding behavior and provide critical information for the development and evaluation of novel approaches to combat cardiometabolic diseases associated with aging.

SENESCENCE, EPIGENETICS, AND METFORMIN A GENOME-WIDE INTEGRATIVE STUDY OF DNA METHYLATION, GENE EXPRESSION, AND LATER LIFE HAND GRIP STRENGTH
Mette Soerensen, 1 Jonas Mengel-From, 1 Kaare Christensen, 2 Lene Christiansen, 3 and Qihua Tan, 1 1.University of Southern Denmark, Odense C, Denmark, 2. University of Southern Denmark, Odense C, Syddanmark, Denmark, 3. Copenhagen University Hospital, Copenhagen Ø, Denmark Hand grip strength (HS) measures muscular strength and associates with multiple health outcomes and mortality.Studies of epigenetic and transcriptomic markers could help elucidate the biology behind HS; markers for which monozygotic (MZ) twins are excellent study populations.We performed integrated enrichment analyses (IEA) of an epigenome-wide association analysis (EWAS) and a transcriptome-wide association analysis (TWAS) of HS in blood samples of 452 MZ twins (56-80 years of age).Unsupervised IEA were conducted by the KeyPathwayMiner algorithm, while supervised IEA were performed by the KEGG and Reactome databases.No individual CpG site or probe passed correction for multiple testing.Investigating the overlap in genes with p-values<0.01,0.005 or 0.001 in the EWAS and TWAS, revealed 67, 21 and 2 unique genes, respectively.The latter 2 were TESK2 and VWA1.By the supervised approach, the 67-gene overlap identified three pathways related to "antigen processing and presentation", driven by HLA-A, HLA-B, TAP2 and PSME2.With the unsupervised approach the 21-gene and 67-gene overlaps revealed networks containing 7 and 19 genes, respectively.Exception nodes (added by the algorithm for structure) were CREBBP and CSNK2A2 for the former, and APP and HSP90AB1 for the latter.The remaining IEA revealed no gene sets or networks.Several of these genes have previously been linked to HS relevant traits, e.g.arthritis (HLA-A, HLA-B and TAP2), smooth muscle and cardiovascular function (TESK2, HLA-B and APP) and sarcopenia (HSP90AB1).Hence, this study reports genes and pathways previously reported for physical functioning, yet also novel candidates for further verification.

A PANEL OF DNA METHYLATION AND PROTEOMIC BIOMARKERS FOR SPECIFIC AGING PATHWAYS
Albert Higgins-Chen, 1 Luigi Ferrucci, 2 and Morgan Levine, 3 1.Yale School of Medicine, New Haven, Connecticut, United States, 2. National Institute on Aging, Bethesda, Maryland, United States, 3. Yale University School of Medicine, New Haven, Connecticut, United States Most aging biomarkers such as DNA methylation and proteomic clocks have focused on measuring overall "biological age," a single number that predicts age-related morbidity and mortality better than absolute chronological age.While intuitive and interpretable, this single biological age number does not account for the possibility that different individuals may preferentially experience aging in different molecular and cellular pathways, and therefore does not suggest personalized aging interventions.We reasoned that a panel of biomarkers each capturing specific aging pathways, such as mitochondrial dysfunction or cellular senescence, may capture the heterogeneity of aging better than existing composite measures.To address this, we employed weighted gene co-expression network analysis to cluster tissue-specific transcriptomes and the serum proteome into specific modules with distinct biological functions and characterized how these modules change with age.We trained DNA methylation proxies of these functional modules that we then applied to independent validation data to identify associations with age-related morbidity and mortality.Clustering analysis using the DNA methylation biomarkers showed that different individuals show distinct patterns of aging.These pathway-specific biomarkers will elucidate how different aging mechanisms interact with each other to produce the larger phenomenon of aging, and for evaluating novel therapeutics targeting specific hallmarks of aging.

AGE-DEPENDENT CHANGES IN NUCLEAR MECHANOTRANSDUCTION AS A DRIVER OF SARCOPENIA
Shama Iyer, 1 Christopher Ward, 1 Joseph Stains, 1 Alice Ryan, 2 Eric Folker, 3 and Richard Lovering, 1 1.University of Maryland School of Medicine,Baltimore,Maryland,United States,2. Baltimore VA Medical Center,Baltimore,Maryland,United States,3. Boston College,Chestnut Hill,Massachusetts,United States Informed by evidence that dysregulated nuclear dynamics and nuclear transport may contribute to atrophy in diseased skeletal muscle, the purpose of this study was to assess nuclear deformability, permeability, transport, and mechano-signaling outputs (YAP/TAZ, a marker of mechanoresponsiveness, and their downstream genes) in aging skeletal muscle.We hypothesized that aging muscle would show changes in: proteins within LINC (linker of the nucleus to the cytoskeleton) complex, lamina and nuclear pore complex (NPC), and mechano-signaling outputs, with consequent decreased nuclear deformability and increased permeability.We further expected an increase in nuclear strain would increase nuclear YAP/TAZ and downstream indicators of YAP activity (Ankrd1, Cyr61).We used young, adult and aged C57BL6 mice (~4, 14, and 26 months, respectively).Nuclei were less deformable to passive mechanical stretch ex-vivo in adult muscle fibers compared to young muscle fibers.LINC protein gene expression, YAP/TAZ protein, and expression of their downstream genes were significantly increased in adult muscles compared to young muscles.YAP/ TAZ protein and their downstream genes were further increased in aged muscles, indicating hyperactivation of YAP/ TAZ in aging muscle.Changes with aging in the lamina and NPC included a loss of lamin β1, Nup107 and POM 121, which could underlie the increased nuclear permeability we found in nuclei of aged muscle.In summary, these data highlight a possible role for LINC, lamina and NPC in changes of aging-related nuclear dynamics and mechano-sensing, and may represent therapeutic targets for sarcopenia.Future studies will examine how altering these components affects muscle function during aging.