Rebalancing the motor circuit restores movement in a Caenorhabditis elegans model for TDP-43 toxicity.

Amyotrophic lateral sclerosis can be caused by abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm of neurons. Here, we use a C. elegans model for TDP-43-induced toxicity to identify the biological mechanisms that lead to disease-related phenotypes. By applying deep behavioral phenotyping and subsequent dissection of the neuromuscular circuit, we show that TDP-43 worms have profound defects in GABA neurons. Moreover, acetylcholine neurons appear functionally silenced. Enhancing functional output of repressed acetylcholine neurons at the level of, among others, G-protein-coupled receptors restores neurotransmission, but inefficiently rescues locomotion. Rebalancing the excitatory-to-inhibitory ratio in the neuromuscular system by simultaneous stimulation of the affected GABA- and acetylcholine neurons, however, not only synergizes the effects of boosting individual neurotransmitter systems, but instantaneously improves movement. Our results suggest that interventions accounting for the altered connectome may be more efficient in restoring motor function than those solely focusing on diseased neuron populations.

RTN2 deficiency results in an autosomal recessive distal motor neuropathy with lower limb spasticity.

Heterozygous RTN2 variants have been previously identified in a limited cohort of families affected by autosomal dominant spastic paraplegia (SPG12-OMIM:604805) with a variable age of onset. Nevertheless, the definitive validity of SPG12 remains to be confidently confirmed due to the scarcity of supporting evidence. In this study, we identified and validated seven novel or ultra-rare homozygous loss-of-function RTN2 variants in 14 individuals from seven consanguineous families with distal hereditary motor neuropathy (dHMN) using exome, genome and Sanger sequencing coupled with deep-phenotyping. All affected individuals (seven males and seven females, aged 9-50 years) exhibited weakness in the distal upper and lower limbs, lower limb spasticity and hyperreflexia, with onset in the first decade of life. Nerve conduction studies revealed axonal motor neuropathy with neurogenic changes in the electromyography. Despite a slowly progressive disease course, all patients remained ambulatory over a mean disease duration of 19.71 ± 13.70 years. Characterization of Caenorhabditis elegans RTN2 homologous loss-of-function variants demonstrated morphological and behavioural differences compared with the parental strain. Treatment of the mutant with an endoplasmic/sarcoplasmic reticulum Ca2+ reuptake inhibitor (2,5-di-tert-butylhydroquinone) rescued key phenotypic differences, suggesting a potential therapeutic benefit for RTN2-disorder. Despite RTN2 being an endoplasmic reticulum (ER)-resident membrane shaping protein, our analysis of patient fibroblast cells did not find significant alterations in ER structure or the response to ER stress. Our findings delineate a distinct form of autosomal recessive dHMN with pyramidal features associated with RTN2 deficiency. This phenotype shares similarities with SIGMAR1-related dHMN and Silver-like syndromes, providing valuable insights into the clinical spectrum and potential therapeutic strategies for RTN2-related dHMN.

A new Caenorhabditis elegans model to study copper toxicity in Wilson disease.

Wilson disease (WD) is caused by mutations in the ATP7B gene that encodes a copper (Cu) transporting ATPase whose trafficking from the Golgi to endo-lysosomal compartments drives sequestration of excess Cu and its further excretion from hepatocytes into the bile. Loss of ATP7B function leads to toxic Cu overload in the liver and subsequently in the brain, causing fatal hepatic and neurological abnormalities. The limitations of existing WD therapies call for the development of new therapeutic approaches, which require an amenable animal model system for screening and validation of drugs and molecular targets. To achieve this objective, we generated a mutant Caenorhabditis elegans strain with a substitution of a conserved histidine (H828Q) in the ATP7B ortholog cua-1 corresponding to the most common ATP7B variant (H1069Q) that causes WD. cua-1 mutant animals exhibited very poor resistance to Cu compared to the wild-type strain. This manifested in a strong delay in larval development, a shorter lifespan, impaired motility, oxidative stress pathway activation, and mitochondrial damage. In addition, morphological analysis revealed several neuronal abnormalities in cua-1 mutant animals exposed to Cu. Further investigation suggested that mutant CUA-1 is retained and degraded in the endoplasmic reticulum, similarly to human ATP7B-H1069Q. As a consequence, the mutant protein does not allow animals to counteract Cu toxicity. Notably, pharmacological correctors of ATP7B-H1069Q reduced Cu toxicity in cua-1 mutants indicating that similar pathogenic molecular pathways might be activated by the H/Q substitution and, therefore, targeted for rescue of ATP7B/CUA-1 function. Taken together, our findings suggest that the newly generated cua-1 mutant strain represents an excellent model for Cu toxicity studies in WD.

Advance Care Planning Among Sexual Minority Men: Sociodemographic, Health Care, and Health Status Predictors.

Objectives: Advance care planning (ACP) specifies decision-making surrogates and preferences for serious illness or end-of-life medical care. ACP research has largely neglected sexual minority men (SMM), a population that experiences disparities in health care and health status. Methods: We examined formal and informal ACP among SMM ages 40+ in the Multicenter AIDS Cohort Study (N = 1,071). Results: For informal ACP (50%), younger SMM and men with past cardiovascular events had greater odds of planning; single men had lower odds of planning. For formal ACP (39%), SMM with greater socioeconomic status had greater odds of planning; SMM who were younger, of racial/ethnic minority identities, who were single or in a relationship without legal protections, and who lacked a primary care home had lower odds of planning. Discussion: Findings warrant further exploration of both informal and formal planning. More equitable, culturally-humble engagement of SMM may facilitate access, uptake, and person-centered planning.

Dissecting the genetic landscape of GPCR signaling through phenotypic profiling in C. elegans.

G protein-coupled receptors (GPCRs) mediate responses to various extracellular and intracellular cues. However, the large number of GPCR genes and their substantial functional redundancy make it challenging to systematically dissect GPCR functions in vivo. Here, we employ a CRISPR/Cas9-based approach, disrupting 1654 GPCR-encoding genes in 284 strains and mutating 152 neuropeptide-encoding genes in 38 strains in C. elegans. These two mutant libraries enable effective deorphanization of chemoreceptors, and characterization of receptors for neuropeptides in various cellular processes. Mutating a set of closely related GPCRs in a single strain permits the assignment of functions to GPCRs with functional redundancy. Our analyses identify a neuropeptide that interacts with three receptors in hypoxia-evoked locomotory responses, unveil a collection of regulators in pathogen-induced immune responses, and define receptors for the volatile food-related odorants. These results establish our GPCR and neuropeptide mutant libraries as valuable resources for the C. elegans community to expedite studies of GPCR signaling in multiple contexts.

Associations of past-year stigma and psychosocial syndemic conditions: Considerations for intersectional stigma measures among Black Sexual Minority Men.

This secondary analysis of a mixed serostatus sample of Black sexual minority men (BSMM) used conditional inference tree methods to explore associations of past-year experienced stigma and psychosocial syndemic conditions. Experienced stigmas were attributed to race, sexuality, socioeconomic status, HIV status or some "other" reason. Psychosocial syndemic conditions studied included physical assault, intimate partner violence, polysubstance use, and depression symptomology. Data are from Promoting Our Worth, Equality and Resilience (POWER), a serial, cross-sectional study conducted between 2014-2017 (N=4430). Experiences of multiple stigmas were reported by n=938 (22.1%) of BSMM. Conditional inference tree results revealed that HIV-related stigma and its intersection with "other" stigma showed the greatest variance in psychosocial condition prevalence. Our findings suggest that when developing intercategorical intersectional analyses with BSMM, there are important stigmas for BSMM beyond those attributed to race, sexuality, and SES, particularly intersecting with HIV-related stigma. Conditional inference tree analysis shows promise in quantitative explorations of intersectional stigma with BSMM, but will benefit from the inclusion of additional forms of stigma, which should be considered by the field moving forward.

Effects of internalised racism and internalised homophobia on sexual behaviours among black gay and bisexual men in the USA: a systematic review protocol.

INTRODUCTION: Black gay and bisexual men are overburdened by HIV in the USA. While the socioecological model has been applied to understand potential mechanisms of HIV acquisition among black gay and bisexual men, there is mixed evidence on the impact of internalised stigma on HIV risk among this population. This systematic review protocol paper outlines the systematic review being conducted to determine the relationship between internalised racism, internalised homophobia and engagement in sexual behaviour, which puts individuals at risk for HIV infection. METHODS AND ANALYSIS: For the review, we will conduct a systematic review of the literature, summarise and critique published scholarly literature on the associations between forms of internalised stigma and sexual behaviours among black gay and bisexual men. We will conduct a systematic search of published qualitative and quantitative research studies published during and after 1993. The searches will be conducted in Ovid Medline, Ovid APA PsycInfo and EBSCO SocINDEX databases. Studies will be included if they were conducted in the USA, with samples that comprised African American/black cisgender gay, bisexual, queer and other men who have sex with men, measured internalised racism and/or internalised homophobia, and assessed sexual behaviour risk for HIV acquisition. ETHICS AND DISSEMINATION: No ethical approval will be required for this review. We will report our findings using the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Findings of this review may offer new opportunities to study internalised mechanisms impacting outcomes and to identify research gaps and spur additional queries in the group most disproportionately impacted by HIV.

Longitudinal associations of relationship support and strain and internalized homophobia with mental health among middle-aged and older gay and bisexual men.

Objectives: Mental health concerns (e.g. depression, anxiety) that negatively impact gay, bisexual, and other men who have sex with men (GBMSM) persist over the life course and into old age, but less is known about potential contributors to GBMSM's mental health. Close relationships can be a source of risk or resilience from stress, exerting direct relationships on mental health, and may mediate well-established associations between minority stress and mental health. This study examined whether primary partner relationship support and strain were uniquely associated with, and mediated the association between internalized homophobia, and mental health among older GBMSM.Methods: GBMSM (N = 517, M age = 60) from the Multicenter AIDS Cohort Study, who were in primary relationships with men, provided self-report data at four timepoints. We used multilevel modeling to examine longitudinal associations among relationship support and strain and internalized homophobia with depression and anxiety.Results: Relationship strain, but not support, was positively associated with mental health concerns longitudinally. There was a significant, positive indirect effect of internalized homophobia on depression and anxiety through strain, but no support. Internalized homophobia was positively associated with relationship strain, which was positively associated with mental health symptoms longitudinally.Conclusions: Relationship strain was associated with depression and anxiety longitudinally among middle-aged and older GBMSM and mediated associations of internalized homophobia with mental health. The role of partner support warrants further investigation. Mental health interventions are critically needed for older GBMSM and, for partnered GBMSM, should include strategies for reducing relationship strain to foster well-being.

Grit is associated with psychological health among older sexual minority men.

Objectives: Studies have shown that grit-defined as perseverance and passion for achieving one's long-term goals-is associated with improved health outcomes, including lower levels of psychological distress. However, the psychometric properties of the original Grit Scale (Grit-O Scale) has not been validated among sexual minority men (SMM). The present study aimed to validate the Grit-O Scale among a sample of older SMM and assess the relationships between the Grit-O Scale factors and symptoms of psychological distress.Method: We used data from a single visit of participants in the Multicenter AIDS Cohort Study (MACS) Healthy Aging longitudinal study. The sample included 981 older SMM (mean age = 61, SD = 8.5) with and without HIV. We conducted confirmatory factor analysis (CFA) to identify the two factors of the Grit-O Scale: consistency of interest and perseverance of effort. We also conducted a latent profile analysis (LPA) to identify distinct profiles of psychological distress from self-reported scales of depression, anxiety, and perceived stress.Results:The Grit-O Scale showed acceptable reliability estimates for the items with Cronbach's alpha reliability coefficients ranging from 0.77 to 0.82. The CFA identified the two factors of the Grit-O Scale with acceptable model fit (root mean square error of approximation = 0.058 [95% CI = 0.050, 0.067], comparative fit index = 0.95, Tucker-Lewis Index = 0.93, standardized root mean square residual = 0.07). The LPA yielded three mutually exclusive profiles of psychological distress (profile 1: low stress, anxiety, and depression; profile 2: high stress and depression and low anxiety; and profile 3: high stress, anxiety, and depression). In adjusted multinominal logistic regression analysis, we found that both higher levels of consistency of interest and perseverance of effort factors of the Grit-O Scale were significantly associated with decreased odds of being in profiles 2 and 3 compared with being in profile 1.Conclusion: Our findings support the use of the Grit-O Scale among older SMM. Grit factors could explain variability in the negative psychological symptoms among older SMM and warrant further investigation.Supplemental data for this article is available online at http://dx.doi.org/10.1080/13607863.2022.2032594.

The Effect of Discrimination and Resilience on Depressive Symptoms among Middle-Aged and Older Men who have Sex with Men.

This study investigated if homophobic and racist discrimination increased depressive symptoms among 960 middle-aged and older men who have sex with men (MSM) and how resilience moderated these relationships. We used five waves of longitudinal data from the Healthy Aging sub-study of the Multicenter AIDS Cohort Study (MACS). We used linear regression analyses to model depressive symptoms as a function of discrimination. We used linear mixed analyses to model changes in mean resilience scores across visits. We used linear regression analyses to model depressive symptoms as a function of changes in resilience and to test the moderation effects of resilience on the relationship between discrimination and depressive symptoms. The models accounted for repeated measures of resilience. Men who experienced external and internal homophobia had greater depressive symptoms (ß: 2.08; 95% Confidence Interval: 0.65, 3.51; ß: 1.60; 95% Confidence Interval: 0.76, 2.44). Men experienced significant changes in mean resilience levels across visits (F = 2.84, p = 0.02). Men with a greater positive change in resilience had lower depressive symptoms (ß: -0.95; 95% Confidence Interval: -1.47, -0.43). Men with higher average resilience levels had lower depressive symptoms (ß: -5.08; 95% Confidence Interval: -5.68, -4.49). Men's resilience did not moderate the relationship between homophobia and depressive symptoms. Significant associations of external and internal homophobia with greater depressive symptoms present targets for future research and interventions among middle-aged and older MSM. Significant associations of average and positive changes in resilience with lower depressive symptoms provide aims for future research and interventions with this population.

Bi-allelic loss-of-function variants in PPFIBP1 cause a neurodevelopmental disorder with microcephaly, epilepsy, and periventricular calcifications.

PPFIBP1 encodes for the liprin-ß1 protein, which has been shown to play a role in neuronal outgrowth and synapse formation in Drosophila melanogaster. By exome and genome sequencing, we detected nine ultra-rare homozygous loss-of-function variants in 16 individuals from 12 unrelated families. The individuals presented with moderate to profound developmental delay, often refractory early-onset epilepsy, and progressive microcephaly. Further common clinical findings included muscular hyper- and hypotonia, spasticity, failure to thrive and short stature, feeding difficulties, impaired vision, and congenital heart defects. Neuroimaging revealed abnormalities of brain morphology with leukoencephalopathy, ventriculomegaly, cortical abnormalities, and intracranial periventricular calcifications as major features. In a fetus with intracranial calcifications, we identified a rare homozygous missense variant that by structural analysis was predicted to disturb the topology of the SAM domain region that is essential for protein-protein interaction. For further insight into the effects of PPFIBP1 loss of function, we performed automated behavioral phenotyping of a Caenorhabditis elegans PPFIBP1/hlb-1 knockout model, which revealed defects in spontaneous and light-induced behavior and confirmed resistance to the acetylcholinesterase inhibitor aldicarb, suggesting a defect in the neuronal presynaptic zone. In conclusion, we establish bi-allelic loss-of-function variants in PPFIBP1 as a cause of an autosomal recessive severe neurodevelopmental disorder with early-onset epilepsy, microcephaly, and periventricular calcifications.

Biopsychosocial Health Outcomes and Experienced Intersectional Stigma in a Mixed HIV Serostatus Longitudinal Cohort of Aging Sexual Minority Men, United States, 2008‒2019.

Objectives. To determine whether intersectional stigma is longitudinally associated with biopsychosocial outcomes. Methods. We measured experienced intersectional stigma (EIS; ≥ 2 identity-related attributions) among sexual minority men (SMM) in the United States participating in the Multicenter AIDS Cohort Study. We assessed longitudinal associations between EIS (2008‒2009) and concurrent and future hypertension, diabetes, dyslipidemia, antiretroviral therapy adherence, HIV viremia, health care underutilization, and depression symptoms (2008‒2019). We conducted causal mediation to assess the contribution of intersectional stigma to the relationship between self-identified Black race and persistently uncontrolled outcomes. Results. The mean age (n = 1806) was 51.8 years (range = 22-84 years). Of participants, 23.1% self-identified as Black; 48.3% were living with HIV. Participants reporting EIS (30.8%) had higher odds of hypertension, dyslipidemia, diabetes, depression symptoms, health care underutilization, and suboptimal antiretroviral therapy adherence compared with participants who did not report EIS. EIS mediated the relationship between self-identified Black race and uncontrolled outcomes. Conclusions. Our findings demonstrate that EIS is a durable driver of biopsychosocial health outcomes over the life course. Public Health Implications. There is a critical need for interventions to reduce intersectional stigma, help SMM cope with intersectional stigma, and enact policies protecting minoritized people from discriminatory acts. (Am J Public Health. 2022;112(S4):S452-S462. https://doi.org/10.2105/AJPH.2022.306735).

Megapixel camera arrays enable high-resolution animal tracking in multiwell plates.

Tracking small laboratory animals such as flies, fish, and worms is used for phenotyping in neuroscience, genetics, disease modelling, and drug discovery. An imaging system with sufficient throughput and spatiotemporal resolution would be capable of imaging a large number of animals, estimating their pose, and quantifying detailed behavioural differences at a scale where hundreds of treatments could be tested simultaneously. Here we report an array of six 12-megapixel cameras that record all the wells of a 96-well plate with sufficient resolution to estimate the pose of C. elegans worms and to extract high-dimensional phenotypic fingerprints. We use the system to study behavioural variability across wild isolates, the sensitisation of worms to repeated blue light stimulation, the phenotypes of worm disease models, and worms' behavioural responses to drug treatment. Because the system is compatible with standard multiwell plates, it makes computational ethological approaches accessible in existing high-throughput pipelines.

Psychological Connection to the Gay Community and Negative Self-Appraisals in Middle-Aged and Older Men Who Have Sex With Men: The Mediating Effects of Fitness Engagement.

OBJECTIVES: Connections to the gay community may elicit negative self-appraisals among men who have sex with men (MSM), which may be exacerbated for people with HIV (PWH). Fitness engagement may mediate self-appraisals by maintaining or improving appearance and health. We hypothesized that gay community connections would be positively related to negative self-appraisal and explored whether this association would be mediated by fitness engagement and moderated by HIV status. METHOD: Data were obtained from the Multicenter AIDS Cohort Healthy Aging study (N = 1,026; PWH n = 525; people without HIV [PWOH] n = 501). Structural equation modeling (SEM) examined associations between gay community connections, negative self-appraisal (body image dissatisfaction, self-perception of aging), and fitness engagement (physical activity, motivation to be fit). Multiple-group SEM tested the moderating effects of HIV serostatus. RESULTS: The SEM fit the data well (root mean square error of approximation = 0.056; 90% CI: 0.046, 0.066). Connection to the gay community was inversely related to negative self-appraisals and positively related to fitness engagement. Fitness engagement mediated the association between community connections and negative self-appraisal and was inversely related to negative self-appraisals. Among PWH, the association between community connections and self-appraisal was weaker and the effect of fitness engagement on negative self-appraisal was stronger compared to PWOH. DISCUSSION: Connection to the gay community may be a source of resilience for aging MSM by lessening negative self-appraisals and promoting strategies that address body image dissatisfaction and self-perceptions of aging. Interventions facilitating connections to the gay community may support healthy aging in this population.

Evaluating the effectiveness of problem-solving courts at preventing fatal and non-fatal opioid events: preliminary findings from Indiana.

BACKGROUND: Fatal and non-fatal events associated with drug misuse are skyrocketing in most United States jurisdictions, including Indiana. Historically, the role of the judiciary is to arrest, impose sanctions and protect society from harm. Adults arrested for drug abuse in Indiana can be sentenced to 1 of 17 correctional facilities. As an alternative, they may be eligible to participate in a problem-solving court (PSC) programme that refers individuals to treatment as a pretrial diversionary strategy. The aim of the study is to determine which interventions offered by PSCs and correctional facilities impact morbidity and mortality. The study began in 2019 and will end in 2023; therefore, the results in this manuscript are preliminary. METHODS: The study cohort included two populations arrested for drug misuse: (1) adults sentenced to Indianan correctional facilities (1 January 2018 to 30 June 2021) and (2) adults participating in an Indiana PSC programme (1 January 2018 to 30 June 2021). The study used a mixed-methods design that integrated qualitative interviews of deputy wardens, PSC team members and service providers with the following quantitative datasets: sentencing information, emergency department visits, inpatient hospitalization admissions, prescription drug monitoring programme data and death records. The individuals will be followed at 2-week, 4-week, 6-month and 1-year intervals post-release. Difference-in-difference and time-to-event analyses will identify impactful interventions. A model will be created to show the effect of impactful interventions in Indiana counties that do not have PSCs. RESULTS: Findings are preliminary. There is variability amongst correctional facilities regarding programme eligibility, provided services and provision of medication-assisted treatment. All correctional facilities were severely impacted by the COVID-19 pandemic. CONCLUSION: It is anticipated that the adoption of impactful interventions will lower opioid-related morbidity and mortality rates.

Negative Perception of Aging Is Associated With Frailty Transitions Within a Cohort of Sexual Minority Men.

BACKGROUND AND OBJECTIVES: Older people have an increased risk of developing frailty, an age-related clinical syndrome associated with worse health outcomes. This study examined the effect of self-perception of aging (ie, age discrepancy-individuals feel younger/older than their chronological age and aging satisfaction) on frailty transitions. RESEARCH DESIGN AND METHODS: We use longitudinal data from 549 HIV-/499 HIV+ sexual minority men aged 50 years or older enrolled in the Multicenter AIDS Cohort Study. To test the association of self-perception of aging on transitions between states of frailty (nonfrail/frail), defined using Fried Frailty Phenotype, a multinomial modeling was used. RESULTS: With remaining nonfrail as the referent group, participants reporting low aging satisfaction (vs moderate aging satisfaction) had increased odds of transitioning from nonfrail to frail (odds ratio [OR]: 2.72; 95% confidence interval [CI]: 1.56-4.74), frail to nonfrail (OR: 3.40; 95% CI: 1.62-7.12), or remaining frail (frail to frail; OR: 6.64; 95% CI: 3.88-11.38). Participants reporting older subjective age (vs no age discrepancy) had increased odds of transitioning from nonfrail to frail (OR: 2.50; 95% CI: 1.11-5.64), frail to nonfrail (OR: 4.47; 95% CI: 1.85-10.81), or remaining frail (frail to frail; OR: 5.68; 95% CI: 3.06-10.56). High aging satisfaction and younger subjective age were not statistically associated with frailty transitions. DISCUSSION AND IMPLICATIONS: Our findings show that negative self-perception of aging (ie, older subjective age and low aging satisfaction) is associated with frailty transitions (nonfrail to frail, frail to nonfrail, and frail to frail) when compared to remaining nonfrail.

Viral suppression among middle-aged and aging MSM living with HIV: Partnership type and quality.

Functional support-the availability of material aid, emotional support, or companionship-promotes general well-being. For men who have sex with men (MSM) living with HIV, having a person who supports you associates with viral suppression. This study examines the association between supportive partnerships and HIV viral suppression among middle-aged and aging MSM living with HIV. A total of 423 middle-aged and aging MSM (mean age, 58.2 years) from the Multicenter AIDS Cohort Study provided self-reported data about their partnerships. Separate Poisson regression models assessed how partnership type, support, strain, and duration from April 2017 were associated with repeated viral load measurements up to April 2019. Of the follow-up visits (N = 1289), 90.0% of participants were virally suppressed. Most participants reported being non-Hispanic White (61.0%) and college-educated (83.4%). Participants were asked about their primary partnerships (i.e., "someone they are committed to above anyone else") and secondary partnerships (i.e., those who can also be intimate or supportive but not necessarily romantic or sexual). The participants reported: no partnerships (45.2%), only primary partnerships (31.0%), only secondary partnerships (11.1%), or both primary and secondary partnerships (12.8%). Primary and secondary partnerships had mean (SD) durations of 15.9 (11.3) and 25.2 (16.5) years, respectively. Participants reporting both primary and secondary partnerships (compared with no partnership) showed significantly higher odds of being virally suppressed (adjusted prevalence ratio [aPR], 1.04; 95% CI, 1.00-1.08; p = 0.043). Albeit not statistically significant, primary-only (aPR, 1.01; 95% CI, 0.97-1.06; p = 0.547) or secondary-only (aPR, 1.03; 95% CI, 0.98-1.08; p = 0.224) partnership types were positively associated with viral suppression. Partner support and strain were not associated with viral suppression in any partnership group. Being older and non-Hispanic Black were positively and negatively associated with viral suppression, respectively. Encouraging partnerships should be considered one of clinicians' many tools to help middle-aged and aging MSM achieve long-term viral suppression.

A C. elegans model of C9orf72-associated ALS/FTD uncovers a conserved role for eIF2D in RAN translation.

A hexanucleotide repeat expansion GGGGCC in the non-coding region of C9orf72 is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Toxic dipeptide repeats (DPRs) are synthesized from GGGGCC via repeat-associated non-AUG (RAN) translation. Here, we develop C. elegans models that express, either ubiquitously or exclusively in neurons, 75 GGGGCC repeats flanked by intronic C9orf72 sequence. The worms generate DPRs (poly-glycine-alanine [poly-GA], poly-glycine-proline [poly-GP]) and poly-glycine-arginine [poly-GR]), display neurodegeneration, and exhibit locomotor and lifespan defects. Mutation of a non-canonical translation-initiating codon (CUG) upstream of the repeats selectively reduces poly-GA steady-state levels and ameliorates disease, suggesting poly-GA is pathogenic. Importantly, loss-of-function mutations in the eukaryotic translation initiation factor 2D (eif-2D/eIF2D) reduce poly-GA and poly-GP levels, and increase lifespan in both C. elegans models. Our in vitro studies in mammalian cells yield similar results. Here, we show a conserved role for eif-2D/eIF2D in DPR expression.

Increased fidelity of protein synthesis extends lifespan.

Loss of proteostasis is a fundamental process driving aging. Proteostasis is affected by the accuracy of translation, yet the physiological consequence of having fewer protein synthesis errors during multi-cellular organismal aging is poorly understood. Our phylogenetic analysis of RPS23, a key protein in the ribosomal decoding center, uncovered a lysine residue almost universally conserved across all domains of life, which is replaced by an arginine in a small number of hyperthermophilic archaea. When introduced into eukaryotic RPS23 homologs, this mutation leads to accurate translation, as well as heat shock resistance and longer life, in yeast, worms, and flies. Furthermore, we show that anti-aging drugs such as rapamycin, Torin1, and trametinib reduce translation errors, and that rapamycin extends further organismal longevity in RPS23 hyperaccuracy mutants. This implies a unified mode of action for diverse pharmacological anti-aging therapies. These findings pave the way for identifying novel translation accuracy interventions to improve aging.

Quantitative behavioural phenotyping to investigate anaesthesia induced neurobehavioural impairment.

Anaesthesia exposure to the developing nervous system causes neuroapoptosis and behavioural impairment in vertebrate models. Mechanistic understanding is limited, and target-based approaches are challenging. High-throughput methods may be an important parallel approach to drug-discovery and mechanistic research. The nematode worm Caenorhabditis elegans is an ideal candidate model. A rich subset of its behaviour can be studied, and hundreds of behavioural features can be quantified, then aggregated to yield a 'signature'. Perturbation of this behavioural signature may provide a tool that can be used to quantify the effects of anaesthetic regimes, and act as an outcome marker for drug screening and molecular target research. Larval C. elegans were exposed to: isoflurane, ketamine, morphine, dexmedetomidine, and lithium (and combinations). Behaviour was recorded, and videos analysed with automated algorithms to extract behavioural features. Anaesthetic exposure during early development leads to persisting behavioural variation (in total, 125 features across exposure combinations). Higher concentrations, and combinations of isoflurane with ketamine, lead to persistent change in a greater number of features. Morphine and dexmedetomidine do not appear to lead to behavioural impairment. Lithium rescues the neurotoxic phenotype produced by isoflurane. Findings correlate well with vertebrate research: impairment is dependent on agent, is concentration-specific, is more likely with combination therapies, and can potentially be rescued by lithium. These results suggest that C. elegans may be an appropriate model with which to pursue phenotypic screens for drugs that mitigate the neurobehavioural impairment. Some possibilities are suggested for how high-throughput platforms might be organised in service of this field.