Preconditioning Frailty Phenotype Influences Survival and Relapse for Older Allogeneic Transplantation Recipients.

Hematologic malignancies disproportionately affect older adults. Hematopoietic cell transplantation (HCT) is potentially curative, but poor overall survival (OS) has limited its use in older adults. Fried's frailty phenotype (FFP) is a geriatric assessment tool that combines objective and subjective performance measures: gait speed, grip strength, activity level, exhaustion, and weight loss. People meeting ≥3 criteria are classified as frail; 1 or 2 criteria, as pre-frail; and 0 criteria, as fit. To evaluate the association of pre-HCT FFP with post-HCT outcomes, we assessed FFP prior to conditioning for 280 HCT recipients age ≥60 years with acute leukemia or a myeloid neoplasm at 3 institutions. When analyzing survival by age group, patients age ≥70 years had inferior OS compared to patients age 60 to 69 years (P = .002), with corresponding OS estimates of 38.9% (95% confidence interval [CI], 27.8% to 49.9%) and 59.3% (95% CI, 51.9% to 65.9%). Nonrelapse mortality (NRM) also was significantly higher in the older patients (P = .0005); the 2-year cumulative incidences of NRM were 38.5% (95% CI, 27.5% to 49.2%) and 17.2% (95% CI, 12.3% to 22.8%), for older and younger recipients, respectively. The cumulative incidences of relapse did not differ by age group (P = .3435). Roughly one-third (35.5%) of the patients were fit, 57.5% were pre-frail, and 7.5% were frail, with corresponding 2-year OS estimates of 68.4% (95% CI, 57.9% to 76.8%), 45.5% (95% CI, 37.4% to 53.2%), and 45.8% (95% CI, 23.4% to 65.8%) (P = .013). FFP was not significantly associated with NRM, but being frail or pre-frail was associated with a higher rate of disease-related deaths (33.3% and 27.3%, respectively, compared with 17.4% for fit patients; P = .043). In univariate modeling of restricted mean survival time with a 3-year horizon (RMST_3y), the factors that were significantly associated were FFP, age, Karnofsky Performance Status (KPS), Disease Risk Index (DRI), and HCT-specific Comorbidity Index (HCT-CI). Of those factors, only FFP (P = .006), age (P = .006), KPS (P = .004), and DRI (P = .005) were significantly associated in multivariate modeling of RMST_3y. Estimates of RMST_3y were computed and 5 risk-groups were created with survival ranging from 31.4 months for those who were age 60 to 69 years, fit, had KPS 90 to 100, and low/intermediate-risk DRI compared to 10.5 months for those who had high-risk features for all the evaluated factors. In univariate and multivariate analyses for restricted mean time to relapse with a 3-year horizon (RMRT_3y), FFP (pre-frail versus fit, P = .007; frail versus fit, P = .061) and DRI (P = .001) were the only significant factors. Predicted RMRT_3y was longest (30.6 months) for those who were fit and had low/intermediate-risk DRI scores and shortest (19.1 months) for those who were frail and had high-risk or very high-risk DRI scores. Both age and FFP impact survival after HCT. Incorporation of FFP into pre-HCT evaluations may improve decision-making and counseling regarding HCT risk for older adults. Our findings support future trials designed to reverse frailty, such as pre-HCT supervised exercise programs, and correlative analyses to unravel the connection of frailty and relapse to generate future targets for intervention. Finally, exploration of novel HCT platforms to reduce relapse in pre-frail and frail patients, as well as reduce NRM in adults age >70 years, are warranted.

Longitudinal changes in cognitive and physical function and health-related quality of life in older adults with acute myeloid leukemia.

INTRODUCTION: Many older adults with acute myeloid leukemia (AML) do not receive chemotherapy because of physicians' and patients' concern for toxicities and functional decline. This highlights the critical and urgent need to generate knowledge of functional changes following new treatments. MATERIALS AND METHODS: As a part of a pragmatic single-center trial, 59 older adults ≥60 years with AML completed geriatric assessment and health-related quality of life measures before treatment and at one month and three months after chemotherapy initiation. Changes in scores of various geriatric assessment measures were computed by subtracting the baseline score from the one-month and three-month scores for each patient. Established cut-offs were used to determine a clinically meaningful change (improvement or worsening). This study provides results of descriptive exploratory analyses. RESULTS: Patients experienced significant comorbidity burden and a high prevalence of functional impairments before treatment, with 56% of patients having ≥2 comorbid conditions, 69% having abnormal cognitive function (using Montreal Cognitive Assessment), 69% having impaired objective physical function (using Short Physical Performance Battery), and 64% having a positive depression screen (Patient Health Questionnaire-9). Patients (n = 53) received treatment with predominantly low-intensity chemotherapy; six patients received intensive chemotherapy. Among those who completed some or all of the three-month evaluation (N = 43), from baseline before treatment to three months later, cognitive function improved (38.7%) or remained stable (38.7%), objective physical function improved (51.6%) or remained stable (22.6%), and depression scores improved (9.4%) or remained stable (53.1%). Global health status score and role functioning moderately improved by a score of >16. DISCUSSION: An exploratory analysis of our phase 2 trial demonstrated improvement or stabilization of cognitive and physical function and depression score at three months in a high proportion of older survivors of AML, despite a high prevalence of frailty and significant comorbidity burden at baseline. These results demonstrate success of treatment in improving cognitive and physical function and depression score, and, if confirmed in larger studies, should encourage oncologists to offer chemotherapy to older adults with AML. CLINICAL TRIAL REGISTRATION: The study is registered in the ClinicalTrials.gov ID: NCT03226418.

A novel endoplasmic reticulum adaptation is critical for the long-lived Caenorhabditis elegans rpn-10 proteasomal mutant.

The loss of proteostasis due to reduced efficiency of protein degradation pathways plays a key role in multiple age-related diseases and is a hallmark of the aging process. Paradoxically, we have previously reported that the Caenorhabditis elegans rpn-10(ok1865) mutant, which lacks the RPN-10/RPN10/PSMD4 subunit of the 19S regulatory particle of the 26S proteasome, exhibits enhanced cytosolic proteostasis, elevated stress resistance and extended lifespan, despite possessing reduced proteasome function. However, the response of this mutant against threats to endoplasmic reticulum (ER) homeostasis and proteostasis was unknown. Here, we find that the rpn-10 mutant is highly ER stress resistant compared to the wildtype. Under unstressed conditions, the ER unfolded protein response (UPR) is activated in the rpn-10 mutant as signified by increased xbp-1 splicing. This primed response appears to alter ER homeostasis through the upregulated expression of genes involved in ER protein quality control (ERQC), including those in the ER-associated protein degradation (ERAD) pathway. Pertinently, we find that ERQC is critical for the rpn-10 mutant longevity. These changes also alter ER proteostasis, as studied using the C. elegans alpha-1 antitrypsin (AAT) deficiency model, which comprises an intestinal ER-localised transgenic reporter of an aggregation-prone form of AAT called ATZ. The rpn-10 mutant shows a significant reduction in the accumulation of the ATZ reporter, thus indicating that its ER proteostasis is augmented. Via a genetic screen for suppressors of decreased ATZ aggregation in the rpn-10 mutant, we then identified ecps-2/H04D03.3, a novel ortholog of the proteasome-associated adaptor and scaffold protein ECM29/ECPAS. We further show that ecps-2 is required for improved ER proteostasis as well as lifespan extension of the rpn-10 mutant. Thus, we propose that ECPS-2-proteasome functional interactions, alongside additional putative molecular processes, contribute to a novel ERQC adaptation which underlies the superior proteostasis and longevity of the rpn-10 mutant.

Integrating geriatric assessment and genetic profiling to personalize therapy selection in older adults with acute myeloid leukemia.

INTRODUCTION: Survival benefit associated with intensive over low-intensity chemotherapy in older adults with acute myeloid leukemia (AML) is controversial. Geriatric assessment and genetic risk categories correlate with survival following intensive chemotherapy in older adults with AML and can guide treatment selection. MATERIALS AND METHODS: In a single-center trial, we integrated both geriatric assessment, and genetic risk categories to personalize selection of intensive versus low-intensity chemotherapy in older adults ≥60 years with AML (NCT03226418). In the present report, we demonstrate feasibility of this approach. RESULTS: Broad eligibility criteria and co-management of patients with community oncologists allowed enrollment of 45% of all patients with AML treated at our center during the study period. The median time from enrollment to therapy initiation was two days (range 0-9). Over half of the trial patients had a score of ≥3 on hematopoietic cell transplantation comorbidity index, impairment in physical function (Short Physical Performance Battery), and Montreal Cognitive Assessment. Three fit patients received intensive chemotherapy, whereas other patients received low-intensity chemotherapy. Mortality at 30 days from diagnosis was 3.7% (95% confidence interval [CI] 0.7-18.3%) and at 90 days was 29.6% (95% CI 15.9-48.5%). One-year overall survival was 66% (95% CI 60-87%). DISCUSSION: Our data demonstrate the feasibility of integrating geriatric assessment in precision oncology trials to define fitness for intensive chemotherapy. Broad eligibility criteria and academic-community collaboration can expand access to clinical trials.

Disparity in Utilization of Multiagent Therapy for Acute Promyelocytic Leukemia in the United States.

BACKGROUND: Despite high rate of cure in acute promyelocytic leukemia (APL) in clinical trials, outcomes in real-world practice are dismal. We utilized National Cancer Database (NCDB) to explore utilization of multiagent therapy in APL and identify any disparities in treatment in real-world practices. PATIENTS AND METHODS: NCDB categorizes use of systemic chemotherapy into single agent versus multiagent therapy. Some patients received hormonal therapy, immunotherapy, and unknown therapy; details of these treatments could not be ascertained. We therefore used multiple logistic regression analysis to evaluate effects of covariates on the probability of multiagent therapy use in 6678 patients. RESULTS: Compared to patients >60 years, patients aged 0 to 18 years (hazard ratio[HR] 3.2, 95% confidence interval [CI] 1.8-5.5, P< .0001), 19 to 40 years (HR 1.6, 95% CI 1.03-2.54, P= .03), and 41 to 60 years (HR 1.6, 95% CI 1.3-1.9, P< .0001) were more likely to receive multiagent therapy. Patients with Charlson comorbidity index (CCI) of 0 (HR 1.6, 95% CI 1.2-2.3, P= .001) and CCI of 1 (HR 1.4, 95% CI 1.0-1.9, P= .04) had a higher likelihood of receiving multiagent therapy than patients with CCI ≥ 3. Patients treated at academic cancer centers, compared to those treated at community cancer center (HR 0.5, 95% CI 0.3-0.7, P= .001), comprehensive community cancer center (HR 0.7, 95% CI 0.6-0.8, P< .0001), and integrated network cancer center (HR 0.8, 95% CI 0.6-0.9, P= .02) were more likely to be treated with multiagent therapy. Compared to the patients with private insurance, those with Medicaid had increased likelihood (HR 1.2, 95% CI 1.0-1.4, P= .04) whereas uninsured patients had a lower likelihood of receiving multiagent therapy (HR 0.6, 95% CI 0.5-0.8, P= .0005). CONCLUSION: To our knowledge, this study is the first and the largest scale analysis of treatment practices in APL in real-world practices. Our findings highlight significant disparities in treatment of APL based on age, insurance, and health-system factors.

HspB1 Overexpression Improves Life Span and Stress Resistance in an Invertebrate Model.

To explore the role of the small heat shock protein beta 1 (HspB1, also known as Hsp25 in rodents and Hsp27 in humans) in longevity, we created a Caenorhabiditis elegans model with a high level of ubiquitous expression of the naked mole-rat HspB1 protein. The worms showed increased life span under multiple conditions and also increased resistance to heat stress. RNAi experiments suggest that HspB1-induced life extension is dependent on the transcription factors skn-1 (Nrf2) and hsf-1 (Hsf1). RNAseq from HspB1 worms showed an enrichment in several skn-1 target genes, including collagen proteins and lysosomal genes. Expression of HspB1 also improved functional outcomes regulated by SKN-1, specifically oxidative stress resistance and pharyngeal integrity. This work is the first to link a small heat shock protein with collagen function, suggesting a novel role for HspB1 as a hub between canonical heat response signaling and SKN-1 transcription.

Preferences of adults with cancer for systemic cancer treatment: do preferences differ based on age?

Background: We used the Therapy Preference Scale, a 30-item questionnaire, to determine cancer treatment preferences of adults with cancer. Methods: We used Wilcoxon's rank sum test and Fisher's exact test to compare the preferences of younger (<60 years) versus older adults (≥60 years). Results: While 56% of patients would accept treatment offering increased life expectancy at an expense of short-term side effects, 75% preferred maintenance of cognition, functional ability and quality of life to quantity of days. Oral instead of intravenous treatment (p = 0.003), shorter hospital stay (p = 0.03), preservation of cognitive function (p = 0.01) and avoidance of pain (p = 0.02) were more important to older patients compared with younger patients. Conclusion: Many patients prioritized maintenance of cognition, functional ability and quality of life; older patients valued oral treatment, shorter hospital stay, preservation of cognitive function and avoidance of pain.

Lay abstract Understanding the preferences of adults with cancer is important for physicians to develop personalized cancer treatment plans. We used a self-reported 30-item questionnaire, the Therapy Preference Scale, to help patients express their preferences with regard to safety, efficacy and other aspects of therapy. While 56% of the patients in our study would accept treatment offering increased life expectancy at an expense of short-term side effects, 75% preferred maintenance of cognition, functional ability and quality of life to quantity of days. Compared with younger patients, older patients preferred oral instead of intravenous treatment, shorter hospital stay, preservation of cognitive function and avoidance of pain.

Health-related and sociodemographic factors associated with physical frailty among older cancer survivors.

OBJECTIVE: The purpose of this study was to examine factors associated with frailty in older cancer survivors. MATERIALS AND METHODS: This is a cross-sectional study using data from the National Social Health and Aging Project (NSHAP) Wave 2, and includes an in-home, nationally representative sample of community-dwelling adults ≥50 years and older from the United States. Frailty score was computed for each individual using a modified 4-point scale based on the phenotypic frailty. Ordinal logistic regression was used to characterize the association between health-related, sociodemographic factors and frailty. RESULTS: Among the 3377 participants, 461 were cancer survivors (answered "yes" to "ever have cancer other than skin cancer"). A final sample of 394 cancer survivors were included: 59 participants (16.1%) were frail, 219 participants were pre-frail (59.8%), and 88 participants were non-frail (24.0%). The univariate analyses showed increasing age (OR 1.48; CI 1.29-1.72; p-value <.001), comorbidities (OR 1.43; CI 1.25-1.64; p-value <.001), depression (OR 1.27; CI 1.19-1.35; p-value <.001) and low mobility (OR 1.55; CI 1.37-1.78; p-value <.001) were associated with frailty. Participants with high self-rated (good/very good/ excellent) physical health (OR 0.18; CI 0.11-0.30; p < .001) and mental health (OR 0.27; CI 0.15-0.50; p < .001) were less likely to be frail. In a multivariate model, frailty was associated with age, self-rated physical health, depression, ability to perform activities of daily living, and mobility (p < .05). CONCLUSION: The findings highlight the importance of incorporating geriatric assessment into cancer survivorship to prevent and delay the progression of frailty.

Human Connection and Technology Connectivity: A Systematic Review of Available Telehealth Survey Instruments.

CONTEXT: The current upsurge in telehealth use in palliative and hospice care warrants consideration of patient, family caregiver, and interdisciplinary palliative perspectives on telehealth modality and communication experiences. Currently, telehealth experiences and encounters are being described but not yet extensively evaluated by palliative care teams. OBJECTIVES: To locate survey instruments available to assess telehealth interactions, to determine the content and constructs covered by the available instruments, and to describe the patient populations previously surveyed by the existing instruments. METHODS: This study and its reporting followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the protocol registered in The International Prospective Register of Systematic Reviews. Three databases were searched with over 3100 articles analyzed for use of a telehealth survey instrument. RESULTS: Twelve telehealth communication assessment instruments were identified with a mean length of 20 questions, primarily Likert-scale responses with one inclusive of free text and one qualitative inquiry survey. Three inquired only into modality, four queried communication, and five studied both modality and communication experience. Existing telehealth survey instruments are unidirectional in exploring patient or family experience, with two inclusive of provider perspectives. Participant demographics are notably underreported in telehealth experience studies with a frank lack of diversity in ethnic/racial, geographic, age, educational, and income representativeness in current telehealth survey instrument respondents. CONCLUSION: Palliative care teams may consider familiarity with telehealth survey instrument as an essential component to progress from description of telehealth use to evaluation of telehealth encounters. Current survey instrument outcome reports do not represent inclusivity or diversity, although telehealth is now being clinically applied across settings.

Tyrosine aminotransferase is involved in the oxidative stress response by metabolizing meta-tyrosine in Caenorhabditis elegans.

Under oxidative stress conditions, hydroxyl radicals can oxidize the phenyl ring of phenylalanine, producing the abnormal tyrosine isomer meta-tyrosine (m-tyrosine). m-Tyrosine levels are commonly used as a biomarker of oxidative stress, and its accumulation has recently been reported to adversely affect cells, suggesting a direct role for m-tyrosine in oxidative stress effects. We found that the Caenorhabditis elegans ortholog of tyrosine aminotransferase (TATN-1)-the first enzyme involved in the metabolic degradation of tyrosine-is up-regulated in response to oxidative stress and directly activated by the oxidative stress-responsive transcription factor SKN-1. Worms deficient in tyrosine aminotransferase activity displayed increased sensitivity to multiple sources of oxidative stress. Biochemical assays revealed that m-tyrosine is a substrate for TATN-1-mediated deamination, suggesting that TATN-1 also metabolizes m-tyrosine. Consistent with a toxic effect of m-tyrosine and a protective function of TATN-1, tatn-1 mutant worms exhibited delayed development, marked reduction in fertility, and shortened lifespan when exposed to m-tyrosine. A forward genetic screen identified a mutation in the previously uncharacterized gene F01D4.5-homologous with human transcription factor 20 (TCF20) and retinoic acid-induced 1 (RAI1)-that suppresses the adverse phenotypes observed in m-tyrosine-treated tatn-1 mutant worms. RNA-Seq analysis of F01D4.5 mutant worms disclosed a significant reduction in the expression of specific isoforms of genes encoding ribosomal proteins, suggesting that alterations in protein synthesis or ribosome structure could diminish the adverse effects of m-tyrosine. Our findings uncover a critical role for tyrosine aminotransferase in the oxidative stress response via m-tyrosine metabolism.

Cell-autonomous and non-autonomous roles of daf-16 in muscle function and mitochondrial capacity in aging C. elegans.

Sarcopenia, defined as the loss of skeletal muscle mass and strength, contributes to disability and health-related conditions with aging. In vitro studies indicate that age-related mitochondrial dysfunction could play a central role in the development and progression of sarcopenia, but because of limitations in the methods employed, how aging affects muscle mitochondrial function in vivo is not fully understood. We use muscle-targeted fluorescent proteins and the ratiometric ATP reporter, ATeam, to examine changes in muscle mitochondrial mass and morphology, and intracellular ATP levels in C. elegans. We find that the preserved muscle function in aging daf-2 mutants is associated with higher muscle mitochondrial mass, preserved mitochondrial morphology, and higher levels of intracellular ATP. These phenotypes require the daf-16/FOXO transcription factor. Via the tissue-specific rescue of daf-16, we find that daf-16 activity in either muscle or neurons is sufficient to enhance muscle mitochondrial mass, whereas daf-16 activity in the muscle is required for the enhanced muscle function and mobility of the daf-2 mutants. Finally, we show through the use of drugs known to enhance mitochondrial activity that augmenting mitochondrial function leads to improved mobility during aging. These results suggest an important role for mitochondrial function in muscle aging.

Microtubule regulators act in the nervous system to modulate fat metabolism and longevity through DAF-16 in C. elegans.

Microtubule (MT) regulation is involved in both neuronal function and the maintenance of neuronal structure, and MT dysregulation appears to be a general downstream indicator and effector of age-related neurodegeneration. But the role of MTs in natural aging is largely unknown. Here, we demonstrate a role of MT regulators in regulating longevity. We find that loss of EFA-6, a modulator of MT dynamics, can delay both neuronal aging and extend the lifespan of C. elegans. Through the use of genetic mutants affecting other MT-regulating genes in C. elegans, we find that loss of MT stabilizing genes (including ptrn-1 and ptl-1) shortens lifespan, while loss of MT destabilizing gene hdac-6 extends lifespan. Via the use of tissue-specific transgenes, we further show that these MT regulators can act in the nervous system to modulate lifespan. Through RNA-seq analyses, we found that genes involved in lipid metabolism were differentially expressed in MT regulator mutants, and via the use of Nile Red and Oil Red O staining, we show that the MT regulator mutants have altered fat storage. We further find that the increased fat storage and extended lifespan of the long-lived MT regulator mutants are dependent on the DAF-16/FOXO transcription factor. Our results suggest that neuronal MT status might affect organismal aging through DAF-16-regulated changes in fat metabolism, and therefore, MT-based therapies might represent a novel intervention to promote healthy aging.

Pyoverdine, a siderophore from Pseudomonas aeruginosa, translocates into C. elegans, removes iron, and activates a distinct host response.

Pseudomonas aeruginosa, a re-emerging, opportunistic human pathogen, encodes a variety of virulence determinants. Pyoverdine, a siderophore produced by this bacterium, is essential for pathogenesis in mammalian infections. This observation is generally attributed to its roles in acquiring iron and/or regulating other virulence factors. Here we report that pyoverdine translocates into the host, where it binds and extracts iron. Pyoverdine-mediated iron extraction damages host mitochondria, disrupting their function and triggering mitochondrial turnover via autophagy. The host detects this damage via a conserved mitochondrial surveillance pathway mediated by the ESRE network. Our findings illuminate the pathogenic mechanisms of pyoverdine and highlight the importance of this bacterial product in host-pathogen interactions.

The ω-3 fatty acid α-linolenic acid extends Caenorhabditis elegans lifespan via NHR-49/PPARα and oxidation to oxylipins.

The dietary intake of ω-3 polyunsaturated fatty acids has been linked to a reduction in the incidence of aging-associated disease including cardiovascular disease and stroke. Additionally, long-lived Caenorhabditis elegans glp-1 germ line-less mutant animals show a number of changes in lipid metabolism including the increased production of the ω-3 fatty acid, α-linolenic acid (ALA). Here, we show that the treatment of C. elegans with ALA produces a dose-dependent increase in lifespan. The increased longevity of the glp-1 mutant animals is known to be dependent on both the NHR-49/PPARα and SKN-1/Nrf2 transcription factors, although the mechanisms involved are incompletely understood. We find that ALA treatment increased the lifespan of wild-type worms and that these effects required both of these transcription factors. Specifically, NHR-49 was activated by ALA to promote the expression of genes involved in the ß-oxidation of lipids, whereas SKN-1 is not directly activated by ALA, but instead, the exposure of ALA to air results in the oxidation of ALA to a group of compounds termed oxylipins. At least one of the oxylipins activates SKN-1 and enhances the increased longevity resulting from ALA treatment. The results show that ω-3 fatty acids inhibit aging and that these effects could reflect the combined effects of the ω-3 fatty acid and the oxylipin metabolites. The benefits of ω-3 fatty acid consumption on human health may similarly involve the production of oxylipins, and differences in oxylipin conversion could account for at least part of the variability found between observational vs. interventional clinical trials.

DLK-1, SEK-3 and PMK-3 Are Required for the Life Extension Induced by Mitochondrial Bioenergetic Disruption in C. elegans.

Mitochondrial dysfunction underlies numerous age-related pathologies. In an effort to uncover how the detrimental effects of mitochondrial dysfunction might be alleviated, we examined how the nematode C. elegans not only adapts to disruption of the mitochondrial electron transport chain, but in many instances responds with extended lifespan. Studies have shown various retrograde responses are activated in these animals, including the well-studied ATFS-1-dependent mitochondrial unfolded protein response (UPRmt). Such processes fall under the greater rubric of cellular surveillance mechanisms. Here we identify a novel p38 signaling cascade that is required to extend life when the mitochondrial electron transport chain is disrupted in worms, and which is blocked by disruption of the Mitochondrial-associated Degradation (MAD) pathway. This novel cascade is defined by DLK-1 (MAP3K), SEK-3 (MAP2K), PMK-3 (MAPK) and the reporter gene Ptbb-6::GFP. Inhibition of known mitochondrial retrograde responses does not alter induction of Ptbb-6::GFP, instead induction of this reporter often occurs in counterpoint to activation of SKN-1, which we show is under the control of ATFS-1. In those mitochondrial bioenergetic mutants which activate Ptbb-6::GFP, we find that dlk-1, sek-3 and pmk-3 are all required for their life extension.

Roles of the tyrosine isomers meta-tyrosine and ortho-tyrosine in oxidative stress.

The damage to cellular components by reactive oxygen species, termed oxidative stress, both increases with age and likely contributes to age-related diseases including Alzheimer's disease, atherosclerosis, diabetes, and cataract formation. In the setting of oxidative stress, hydroxyl radicals can oxidize the benzyl ring of the amino acid phenylalanine, which then produces the abnormal tyrosine isomers meta-tyrosine or ortho-tyrosine. While elevations in m-tyrosine and o-tyrosine concentrations have been used as a biological marker of oxidative stress, there is emerging evidence from bacterial, plant, and mammalian studies demonstrating that these isomers, particularly m-tyrosine, directly produce adverse effects to cells and tissues. These new findings suggest that the abnormal tyrosine isomers could in fact represent mediators of the effects of oxidative stress. Consequently the accumulation of m- and o-tyrosine may disrupt cellular homeostasis and contribute to disease pathogenesis, and as result, effective defenses against oxidative stress can encompass not only the elimination of reactive oxygen species but also the metabolism and ultimately the removal of the abnormal tyrosine isomers from the cellular amino acid pool. Future research in this area is needed to clarify the biologic mechanisms by which the tyrosine isomers damage cells and disrupt the function of tissues and organs and to identify the metabolic pathways involved in removing the accumulated isomers after exposure to oxidative stress.

Graded Proteasome Dysfunction in Caenorhabditis elegans Activates an Adaptive Response Involving the Conserved SKN-1 and ELT-2 Transcription Factors and the Autophagy-Lysosome Pathway.

The maintenance of cellular proteins in a biologically active and structurally stable state is a vital endeavor involving multiple cellular pathways. One such pathway is the ubiquitin-proteasome system that represents a major route for protein degradation, and reductions in this pathway usually have adverse effects on the health of cells and tissues. Here, we demonstrate that loss-of-function mutants of the Caenorhabditis elegans proteasome subunit, RPN-10, exhibit moderate proteasome dysfunction and unexpectedly develop both increased longevity and enhanced resistance to multiple threats to the proteome, including heat, oxidative stress, and the presence of aggregation prone proteins. The rpn-10 mutant animals survive through the activation of compensatory mechanisms regulated by the conserved SKN-1/Nrf2 and ELT-2/GATA transcription factors that mediate the increased expression of genes encoding proteasome subunits as well as those mediating oxidative- and heat-stress responses. Additionally, we find that the rpn-10 mutant also shows enhanced activity of the autophagy-lysosome pathway as evidenced by increased expression of the multiple autophagy genes including atg-16.2, lgg-1, and bec-1, and also by an increase in GFP::LGG-1 puncta. Consistent with a critical role for this pathway, the enhanced resistance of the rpn-10 mutant to aggregation prone proteins depends on autophagy genes atg-13, atg-16.2, and prmt-1. Furthermore, the rpn-10 mutant is particularly sensitive to the inhibition of lysosome activity via either RNAi or chemical means. We also find that the rpn-10 mutant shows a reduction in the numbers of intestinal lysosomes, and that the elt-2 gene also plays a novel and vital role in controlling the production of functional lysosomes by the intestine. Overall, these experiments suggest that moderate proteasome dysfunction could be leveraged to improve protein homeostasis and organismal health and longevity, and that the rpn-10 mutant provides a unique platform to explore these possibilities.

CRISPR-mediated genome editing and human diseases.

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology has emerged as a powerful technology for genome editing and is now widely used in basic biomedical research to explore gene function. More recently, this technology has been increasingly applied to the study or treatment of human diseases, including Barth syndrome effects on the heart, Duchenne muscular dystrophy, hemophilia, ß-Thalassemia, and cystic fibrosis. CRISPR/Cas9 (CRISPR-associated protein 9) genome editing has been used to correct disease-causing DNA mutations ranging from a single base pair to large deletions in model systems ranging from cells in vitro to animals in vivo. In addition to genetic diseases, CRISPR/Cas9 gene editing has also been applied in immunology-focused applications such as the targeting of C-C chemokine receptor type 5, the programmed death 1 gene, or the creation of chimeric antigen receptors in T cells for purposes such as the treatment of the acquired immune deficiency syndrome (AIDS) or promoting anti-tumor immunotherapy. Furthermore, this technology has been applied to the genetic manipulation of domesticated animals with the goal of producing biologic medical materials, including molecules, cells or organs, on a large scale. Finally, CRISPR/Cas9 has been teamed with induced pluripotent stem (iPS) cells to perform multiple tissue engineering tasks including the creation of disease models or the preparation of donor-specific tissues for transplantation. This review will explore the ways in which the use of CRISPR/Cas9 is opening new doors to the treatment of human diseases.

How Well Do Raters Agree on the Development Stage of Caenorhabditis elegans?

The assessment of inter-rater reliability is a topic that is infrequently addressed in Caenorhabditis elegans research, despite the existence of sophisticated statistical methods and the strong interest in the field in obtaining reliable and accurate data. This study applies statistical modeling as a robust means of analyzing the performance of worm researchers measuring the stage of worm development in terms of the two independent factors that comprise "agreement", which are (1) accuracy, representing trueness, a lack of systematic differences, or lack of bias, and (2) precision, representing reliability or the extent to which random differences are small. In our study, multiple raters assessed the same sample of worms to determine the developmental stage of each animal, and we collected data linking each scorer with their assessment for each worm. To describe the agreement of the raters, we developed a structural equation model with latent variables and thresholds, which assumes that all the raters are jointly scoring each worm. This common factor model separately quantifies the two aspects of agreement. The stage-specific thresholds examine accuracy and characterize the relative biases of each rater during the scoring process. The factor loadings for each rater examine the precision and characterizes the random error of the rater. Within our group, we found that the overall agreement was good, while certain adjustments in particular raters would have decreased systematic differences. Hence, the use of developmental stage as an experimental outcome can be both accurate and precise.