Insight from Wild Yeast Isolates into the Molecular Mechanisms of Lifespan Variation Mediated by Caloric Restriction.

Caloric restriction (CR) is known to extend lifespan across different species and holds great promise for preventing human age-onset pathologies. However, two major challenges exist. First, despite extensive research, the mechanisms of lifespan extension in response to CR remain elusive. Second, genetic differences causing variations in response to CR and genetic factors contributing to variability of CR response on lifespan are largely unknown. Here, we took advantage of natural genetic variation across 46 diploid wild yeast isolates of Saccharomyces species and the lifespan variation under CR conditions to uncover the molecular factors associated with CR response types. We identified genes and metabolic pathways differentially regulated in CR-responsive versus non-responsive strains. Our analysis revealed that altered mitochondrial function and activation of GCN4-mediated environmental stress response are inevitably linked to lifespan variation in response to CR and a unique mitochondrial metabolite might be utilized as a predictive marker for CR response rate. In sum, our data suggests that the effects of CR on longevity may not be universal, even among closely related species or strains of a single species. Since mitochondrial mediated signaling pathways are evolutionarily conserved, the dissection of related genetic pathways will be relevant to understanding the mechanism by which CR elicits its longevity effect.

Stereospecific and Regioselective Synthesis of E-Allylic Alcohols through Reductive Cross Coupling of Terminal Alkynes.

We have developed a convergent method for the synthesis of allylic alcohols that involves a reductive coupling of terminal alkynes with α-chloro boronic esters. The new method affords allylic alcohols with excellent regioselectivity (anti-Markovnikov) and an E/Z ratio greater than 200:1. The reaction can be performed in the presence of a wide range of functional groups and has a substrate scope that complements the stoichiometric alkenylation of α-chloro boronic esters performed using alkenyl lithium and Grignard reagents. The transformation is stereospecific and allows for the robust and highly selective synthesis of chiral allylic alcohols. Our studies support a mechanism that involves hydrocupration of the alkyne and cross-coupling of the alkenyl copper intermediate with α-chloro boronic esters. Experimental evidence excludes a radical mechanism of the cross-coupling step and is consistent with the formation of a boron-ate intermediate and a 1,2-metalate shift.

Existing Nongated CT Coronary Calcium Predicts Operative Risk in Patients Undergoing Noncardiac Surgeries (ENCORES).

BACKGROUND: Preoperative cardiovascular risk stratification before noncardiac surgery is a common clinical challenge. Coronary artery calcium scores from ECG-gated chest computed tomography (CT) imaging are associated with perioperative events. At the time of preoperative evaluation, many patients will not have had ECG-gated CT imaging, but will have had nongated chest CT studies performed for a variety of noncardiac indications. We evaluated relationships between coronary calcium severity estimated from previous nongated chest CT imaging and perioperative major clinical events (MCE) after noncardiac surgery. METHODS: We retrospectively identified consecutive adults age ≥45 years who underwent in-hospital, major noncardiac surgery from 2016 to 2020 at a large academic health system composed of 4 acute care centers. All patients had nongated (contrast or noncontrast) chest CT imaging performed within 1 year before surgery. Coronary calcium in each vessel was retrospectively graded from absent to severe using a 0 to 3 scale (absent, mild, moderate, severe) by physicians blinded to clinical data. The estimated coronary calcium burden (ECCB) was computed as the sum of scores for each coronary artery (0 to 9 scale). A Revised Cardiac Risk Index was calculated for each patient. Perioperative MCE was defined as all-cause death or myocardial infarction within 30 days of surgery. RESULTS: A total of 2554 patients (median age, 68 years; 49.7% women; median Revised Cardiac Risk Index, 1) were included. The median time interval from nongated chest CT imaging to noncardiac surgery was 15 days (interquartile range, 3-106 days). The median ECCB was 1 (interquartile range, 0-3). Perioperative MCE occurred in 136 (5.2%) patients. Higher ECCB values were associated with stepwise increases in perioperative MCE (0: 2.9%, 1-2: 3.7%, 3-5: 8.0%; 6-9: 12.6%, P<0.001). Addition of ECCB to a model with the Revised Cardiac Risk Index improved the C-statistic for MCE (from 0.675 to 0.712, P=0.018), with a net reclassification improvement of 0.428 (95% CI, 0.254-0.601, P<0.0001). An ECCB ≥3 was associated with 2-fold higher adjusted odds of MCE versus an ECCB <3 (adjusted odds ratio, 2.11 [95% CI, 1.42-3.12]). CONCLUSIONS: Prevalence and severity of coronary calcium obtained from existing nongated chest CT imaging improve preoperative clinical risk stratification before noncardiac surgery.

The million-molecule challenge: a moonshot project to rapidly advance longevity intervention discovery.

Targeting aging is the future of twenty-first century preventative medicine. Small molecule interventions that promote healthy longevity are known, but few are well-developed and discovery of novel, robust interventions has stagnated. To accelerate longevity intervention discovery and development, high-throughput systems are needed that can perform unbiased drug screening and directly measure lifespan and healthspan metrics in whole animals. C. elegans is a powerful model system for this type of drug discovery. Combined with automated data capture and analysis technologies, truly high-throughput longevity drug discovery is possible. In this perspective, we propose the "million-molecule challenge", an effort to quantitatively assess 1,000,000 interventions for longevity within five years. The WormBot-AI, our best-in-class robotics and AI data analysis platform, provides a tool to achieve the million-molecule challenge for pennies per animal tested.

Depression and anxiety among college students at Historically Black and Predominantly White universities during the COVID-19 pandemic: A cross-sectional study.

OBJECTIVE: To assess depression and anxiety among college students during the COVID-19 pandemic and its association with race. PARTICIPANTS: Using a cross-sectional survey, depression and anxiety among college students at a Predominantly White (PWU) and a Historically Black University (HBU) during 2021 were evaluated. METHODS: The patient health questionnaire-9 (PHQ-9), general anxiety disorder-7 (GAD-7), and self-reported sociodemographic characteristics were collected. Chi-square and logistic regression tests examined differences in depression and anxiety based on race. RESULTS: Depression and anxiety among 3,102 students (87% female) were analyzed. Minority racial groups were associated with anxiety (p < 0.01) but not depression in the PWU. Moderately severe and severe depression was higher among the minority race at both the universities (1.76% compared to 0.53% at PWU, and 11.1% compared to 2.4% at HBU). CONCLUSIONS: Depression and anxiety among college students is influenced by racial status. First-generation students were more likely to report depression in both HBU and PWU.

Bilateral Central Retinal Vein Occlusion Secondary to Leukostasis in the Setting of Diffuse Large-B Cell Lymphoma: Case Report.

A woman in her 50's was diagnosed diffuse large B-cell lymphoma (DLBCL) after presenting to hospital in a critical condition, characterised by marked hyperleukocytosis (white cell count 290 x109/L). She subsequently developed painless blurred vision bilaterally, and was diagnosed with bilateral central retinal vein occlusion secondary to leukostasis. She was managed with non-Hodgkin lymphoma R-CHOEP14 (rituximab, cyclophosphamide, doxorubicin, vincristine, etoposide, prednisolone) immunochemotherapy, with her ocular signs and symptoms improving following treatment. Optical coherence tomography and funduscopic examination demonstrated no evidence of intraocular lymphoma. Visual acuity returned to 6/6 in each eye with subsequent resolution of her symptoms. Repeat examination demonstrated stable appearance of her ocular disease.

Associations of ApoE4 status and DHA supplementation on plasma and CSF lipid profiles and entorhinal cortex thickness.

Apolipoprotein ε allele 4 (APOE4) influences the metabolism of polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA). The entorhinal cortex (EC) in the brain is affected early in Alzheimer's disease and is rich in DHA. The purpose of this study is to identify the effect of APOE4 and DHA lipid species on the EC. Plasma and cerebrospinal fluid (CSF) lipidomic measurements were obtained from the DHA Brain Delivery Pilot, a randomized clinical trial of DHA supplementation (n = 10) versus placebo (n = 12) for six months in nondemented older adults stratified by APOE4 status. Wild-type C57B6/J mice were fed a high or low DHA diet for 6 months followed by plasma and brain lipidomic analysis. Levels of phosphatidylcholine DHA (PC 38:6) and cholesterol ester DHA (CE 22:6) had the largest increases in CSF following supplementation (P < 0.001). DHA within triglyceride (TG) lipids in CSF strongly correlated with corresponding plasma TG lipids, and differed by APOE4, with carriers having a lower increase than noncarriers. Changes in plasma PC DHA had the strongest association with changes in EC thickness in millimeters, independent of APOE4 status (P = 0.007). In mice, a high DHA diet increased PUFAs within brain lipids. Our findings demonstrate an exchange of DHA at the CSF-blood barrier and into the brain within all lipid species with APOE having the strongest effect on DHA-containing TGs. The correlation of PC DHA with EC suggests a functional consequence of DHA accretion in high density lipoprotein for the brain.

Hippocampal asymmetry of regional development and structural covariance in preterm neonates.

Premature birth is associated with a high prevalence of neurodevelopmental impairments in surviving infants. The hippocampus is known to be critical for learning and memory, yet the putative effects of hippocampal dysfunction remain poorly understood in preterm neonates. In particular, while asymmetry of the hippocampus has been well noted both structurally and functionally, how preterm birth impairs hippocampal development and to what extent the hippocampus is asymmetrically impaired by preterm birth have not been well delineated. In this study, we compared volumetric growth and shape development in the hippocampal hemispheres and structural covariance (SC) between hippocampal vertices and cortical thickness in cerebral cortex regions between two groups. We found that premature infants had smaller volumes of the right hippocampi only. Lower thickness was observed in the hippocampal head in both hemispheres for preterm neonates compared with full-term peers, though preterm neonates exhibited an accelerated age-related change of hippocampal thickness in the left hippocampi. The SC between the left hippocampi and the limbic lobe of the premature infants was severely impaired compared with the term-born neonates. These findings suggested that the development of the hippocampus during the third trimester may be altered following early extrauterine exposure with a high degree of asymmetry.

Tenofovir diphosphate levels in dried blood spots are associated with virologic failure and resistance to first-line therapy in South Africa: a case-control cohort study.

INTRODUCTION: Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS), a measure of cumulative antiretroviral therapy (ART) adherence, is associated with viral suppression and predicts future viremia in persons with HIV (PWH). However, its utility to identify those at risk for virologic failure (VF) and drug resistance is unknown. To address this, we aimed to establish the association between this adherence biomarker and VF with drug resistance in a cohort of PWH initiating first-line ART in KwaZulu-Natal, South Africa. METHODS: PWH initiating TFV disoproxil fumarate (TDF)-based ART within a parent prospective cohort were evaluated. Using a nested design, DBS for TFV-DP were collected from cases who developed VF (HIV-1 RNA ≥1000 copies/ml) after ≥5 months on ART versus controls, matched 1:2 by site, age, gender, race and ART duration. Cases were categorized as having VF with or without resistance using genotyping. One-way analysis of variance (ANOVA) was used to compare TFV-DP for controls, cases with VF and resistance, and cases with VF without resistance. Data are presented as mean (standard deviation, SD) or geometric mean [95% confidence interval, 95% CI]. RESULTS AND DISCUSSION: One thousand participants were enrolled in the parent study between 2014 and 2016, of which 288 (29%) had DBS available. Of these, 94 (33%) were cases and 194 (67%) were controls; 59% were women. Mean age of our population was 33 (SD 8) years. Genotyping was available in 50 (53%) of the 94 cases. Geometric mean TFV-DP in DBS from controls was 708 [95% CI; 647-773] fmol/punch, which was higher compared to participants having VF with resistance (n = 36), 386 [95% CI; 241-617] fmol/punch and VF without resistance (n = 14), 61 [95% CI; 22-164] fmol/punch; p<0.001. Genotype could not be obtained in 44 (47%) cases. CONCLUSIONS: TFV-DP in DBS showed a stepwise association with VF and drug resistance in South African PWH. Participants having VF with resistance had mid-range concentrations of TFV-DP, which were higher than those for PWH without resistance. Future research on the clinical utility of TFV-DP concentrations in DBS to predict and prevent the development of VF and drug resistance is needed.

Antiaging diets: Separating fact from fiction.

Caloric restriction has been known for nearly a century to extend life span and delay age-associated pathology in laboratory animals. More recently, alternative "antiaging" diet modalities have been described that provide new mechanistic insights and potential clinical applications. These include intermittent fasting, fasting-mimicking diets, ketogenic diets, time-restricted feeding, protein restriction, and dietary restriction of specific amino acids. Despite mainstream popularization of some of these diets, many questions remain about their efficacy outside of a laboratory setting. Studies of these interventions support at least partially overlapping mechanisms of action and provide insights into what appear to be highly conserved mechanisms of biological aging.

Evolution of natural lifespan variation and molecular strategies of extended lifespan in yeast.

To understand the genetic basis and selective forces acting on longevity, it is useful to examine lifespan variation among closely related species, or ecologically diverse isolates of the same species, within a controlled environment. In particular, this approach may lead to understanding mechanisms underlying natural variation in lifespan. Here, we analyzed 76 ecologically diverse wild yeast isolates and discovered a wide diversity of replicative lifespan (RLS). Phylogenetic analyses pointed to genes and environmental factors that strongly interact to modulate the observed aging patterns. We then identified genetic networks causally associated with natural variation in RLS across wild yeast isolates, as well as genes, metabolites, and pathways, many of which have never been associated with yeast lifespan in laboratory settings. In addition, a combined analysis of lifespan-associated metabolic and transcriptomic changes revealed unique adaptations to interconnected amino acid biosynthesis, glutamate metabolism, and mitochondrial function in long-lived strains. Overall, our multiomic and lifespan analyses across diverse isolates of the same species shows how gene-environment interactions shape cellular processes involved in phenotypic variation such as lifespan.

Mechanism of Z-Selective Hydroalkylation of Terminal Alkynes.

This paper describes a detailed mechanistic study of the silver-catalyzed Z-selective hydroalkylation of terminal alkynes. Considering the established mechanistic paradigms for Z-selective hydroalkylation of alkynes, we explored a mechanism based on the radical carbometalation of alkynes. Experimental results have provided strong evidence against the initially proposed radical mechanism and have led us to propose a new mechanism for the Z-selective hydroalkylation of alkynes based on boronate formation and a 1,2-metalate shift. The new mechanism provides a rationale for the excellent Z-selectivity observed in the reaction. A series of stoichiometric experiments has probed the feasibility of the proposed elementary steps and revealed an additional role of the silver catalyst in the protodeboration of an intermediate. Finally, a series of kinetic measurements, KIE experiments, and competition experiments allowed us to identify the turnover limiting step and the resting state of the catalyst. We believe that the results of this study will be useful in the further exploration and development of related transformations of alkynes.

Pterocarpus marsupium extract extends replicative lifespan in budding yeast.

As the molecular mechanisms of biological aging become better understood, there is growing interest in identifying interventions that target those mechanisms to promote extended health and longevity. The budding yeast Saccharomyces cerevisiae has served as a premier model organism for identifying genetic and molecular factors that modulate cellular aging and is a powerful system in which to evaluate candidate longevity interventions. Here we screened a collection of natural products and natural product mixtures for effects on the growth rate, mTOR-mediated growth inhibition, and replicative lifespan. No mTOR inhibitory activity was detected, but several of the treatments affected growth rate and lifespan. The strongest lifespan shortening effects were observed for green tea extract and berberine. The most robust lifespan extension was detected from an extract of Pterocarpus marsupium and another mixture containing Pterocarpus marsupium extract. These findings illustrate the utility of the yeast system for longevity intervention discovery and identify Pterocarpus marsupium extract as a potentially fruitful longevity intervention for testing in higher eukaryotes.

Characterization of Mechanical and Dielectric Properties of Silicone Rubber.

Silicone rubber's silicone-oxygen backbones give unique material properties which are applicable in various biomedical devices. Due to the diversity of potential silicone rubber compositions, the material properties can vary widely. This paper characterizes the dielectric and mechanical properties of two different silicone rubbers, each with a different cure system, and in combination with silicone additives. A tactile mutator (Slacker™) and/or silicone thickener (Thi-vex™) were mixed with platinum-cured and condensation-cured silicone rubber in various concentrations. The dielectric constants, conductivities, and compressive and shear moduli were measured for each sample. Our study contributes novel information about the dielectric and mechanical properties of these two types of silicone rubber and how they change with the addition of two common silicone additives.

The AGE Presents Introduction to Geroscience video lecture series.

The AGE Presents Introduction to Geroscience video lecture series is a collection of high-quality didactic video lectures and associated teaching materials focused on foundational topics in aging biology. The videos are made freely available on YouTube and are targeted toward an audience familiar with concepts learned in the first year of a college undergraduate biology/biomedical major. Members of the American Aging Association also receive the original lecture slides and lecture notes, with additional course materials to be developed in the future. We expect that these lectures will enhance understanding of geroscience among the general public while also providing tools that educators can use in the classroom for high school, undergraduate, and graduate level curricula.

Proceedings from the annual University of Washington Geroscience Symposium, October 23, 2020.

The University of Washington Nathan Shock Center of Excellence in the Biology of Aging in conjunction with the Healthy Aging and Longevity Research Institute held its annual geroscience symposium virtually on October 23, 2020. The symposium was divided into three sessions: (I) organ aging and growth signaling, (II) neurodegeneration and metabolism, and (III) innovative approaches in geroscience and aging research. Nine speakers affiliated with the University of Washington and three invited guest speakers, predominantly trainee, and junior faculty presented their research. Here, we summarize research presented during the symposium. A geroscience special issue, of which this is a part, collects submissions from symposium presenters as well as trainees supported by the Biological Mechanisms of Healthy Aging training program.

Spontaneous Polyploids and Antimutators Compete During the Evolution of Saccharomyces cerevisiae Mutator Cells.

Mutations affecting DNA polymerase exonuclease domains or mismatch repair (MMR) generate "mutator" phenotypes capable of driving tumorigenesis. Cancers with both defects exhibit an explosive increase in mutation burden that appears to reach a threshold, consistent with selection acting against further mutation accumulation. In Saccharomyces cerevisiae haploid yeast, simultaneous defects in polymerase proofreading and MMR select for "antimutator" mutants that suppress the mutator phenotype. We report here that spontaneous polyploids also escape this "error-induced extinction" and routinely outcompete antimutators in evolved haploid cultures. We performed similar experiments to explore how diploid yeast adapt to the mutator phenotype. We first evolved cells with homozygous mutations affecting polymerase δ proofreading and MMR, which we anticipated would favor tetraploid emergence. While tetraploids arose with a low frequency, in most cultures, a single antimutator clone rose to prominence carrying biallelic mutations affecting the polymerase mutator alleles. Variation in mutation rate between subclones from the same culture suggests that there exists continued selection pressure for additional antimutator alleles. We then evolved diploid yeast modeling MMR-deficient cancers with the most common heterozygous exonuclease domain mutation (POLE-P286R). Although these cells grew robustly, within 120 generations, all subclones carried truncating or nonsynonymous mutations in the POLE-P286R homologous allele (pol2-P301R) that suppressed the mutator phenotype as much as 100-fold. Independent adaptive events in the same culture were common. Our findings suggest that analogous tumor cell populations may adapt to the threat of extinction by polyclonal mutations that neutralize the POLE mutator allele and preserve intratumoral genetic diversity for future adaptation.

The Legionella kinase LegK7 exploits the Hippo pathway scaffold protein MOB1A for allostery and substrate phosphorylation.

During infection, the bacterial pathogen Legionella pneumophila manipulates a variety of host cell signaling pathways, including the Hippo pathway which controls cell proliferation and differentiation in eukaryotes. Our previous studies revealed that L. pneumophila encodes the effector kinase LegK7 which phosphorylates MOB1A, a highly conserved scaffold protein of the Hippo pathway. Here, we show that MOB1A, in addition to being a substrate of LegK7, also functions as an allosteric activator of its kinase activity. A crystallographic analysis of the LegK7-MOB1A complex revealed that the N-terminal half of LegK7 is structurally similar to eukaryotic protein kinases, and that MOB1A directly binds to the LegK7 kinase domain. Substitution of interface residues critical for complex formation abrogated allosteric activation of LegK7 both in vitro and within cells and diminished MOB1A phosphorylation. Importantly, the N-terminal extension (NTE) of MOB1A not only regulated complex formation with LegK7 but also served as a docking site for downstream substrates such as the transcriptional coregulator YAP1. Deletion of the NTE from MOB1A or addition of NTE peptides as binding competitors attenuated YAP1 recruitment to and phosphorylation by LegK7. By providing mechanistic insight into the formation and regulation of the LegK7-MOB1A complex, our study unravels a sophisticated molecular mimicry strategy that is used by L. pneumophila to take control of the host cell Hippo pathway.

The importance of diversity and outreach in geroscience research: Insights from the Annual Biomedical Research Conference for Minority Students.

US academic science lacks racial, ethnic, sex, gender, disability, and socioeconomic diversity. Addressing this problem is essential to drive scientific progress but is confounded by broad misunderstandings regarding diverse groups. Increasing representation in science is particularly relevant in geroscience, where our research to maximize healthy human lifespan must also address existing racial and socioeconomic health disparities. The American Aging Association (AGE) is committed to addressing these issues as part of its larger mission to advance and promote geroscience research. Over the last three years, AGE has sponsored an exhibition booth staffed by trainee leaders to promote our society and research at the Annual Biomedical Research Conference for Minority Students (ABRCMS), an ideal venue to interact with diverse students from across the country. Through our interactions with students, advocates, and representatives from other institutions and societies, we have learned a great deal about how to engage and promote the success of diverse students in the sciences. Here, we share these insights that are helping shape our own outreach efforts. In addition to interacting with ABRCMS attendees, we also learned a great deal about how societies like AGE can partner with other organizations to advance our shared goals and the importance of reaching students early in their academic journey to promote their success. Finally, we consider how to grow our outreach efforts beyond ABRCMS to reach those in disadvantaged areas and support students navigating academic science.