Sex‐specific aging in animals: Perspective and future directions

Sex differences in aging occur in many animal species, and they include sex differences in lifespan, in the onset and progression of age‐associated decline, and in physiological and molecular markers of aging. Sex differences in aging vary greatly across the animal kingdom. For example, there are species with longer‐lived females, species where males live longer, and species lacking sex differences in lifespan. The underlying causes of sex differences in aging remain mostly unknown. Currently, we do not understand the molecular drivers of sex differences in aging, or whether they are related to the accepted hallmarks or pillars of aging or linked to other well‐characterized processes. In particular, understanding the role of sex‐determination mechanisms and sex differences in aging is relatively understudied. Here, we take a comparative, interdisciplinary approach to explore various hypotheses about how sex differences in aging arise. We discuss genomic, morphological, and environmental differences between the sexes and how these relate to sex differences in aging. Finally, we present some suggestions for future research in this area and provide recommendations for promising experimental designs.     

Redox imbalance induces remodeling of glucose metabolism in Rhipicephalus microplus embryonic cell line

Carbohydrate metabolism not only functions in supplying cellular energy but also has an important role in maintaining physiological homeostasis and in preventing oxidative damage caused by reactive oxygen species. Previously, we showed that arthropod embryonic cell lines have high tolerance to H₂O₂ exposure. Here, we describe that Rhipicephalus microplus tick embryonic cell line (BME26) employs an adaptive glucose metabolism mechanism that confers tolerance to hydrogen peroxide at concentrations too high for other organisms. This adaptive mechanism sustained by glucose metabolism remodeling promotes cell survival and redox balance in BME26 cell line after millimolar H₂O₂ exposure. The present work shows that this tick cell line could tolerate high H₂O₂ concentrations by initiating a carbohydrate-related adaptive response. We demonstrate that gluconeogenesis was induced as a compensation strategy that involved, among other molecules, the metabolic enzymes NADP-ICDH, G6PDH, and PEPCK. We also found that this phenomenon was coupled to glycogen accumulation and glucose uptake, supporting the pentose phosphate pathway to sustain NADPH production and leading to cell survival and proliferation. Our findings suggest that the described response is not atypical, being also observed in cancer cells, which highlights the importance of this model to all proliferative cells. We propose that these results will be useful in generating basic biological information to support the development of new strategies for disease treatment and parasite control.     

Parasite load evaluation by qPCR and blood culture in Chagas disease and HIV co-infected patients under antiretroviral therapy

Chagas disease also known as American trypanosomiasis, is caused by Trypanosoma cruzi and transmitted by triatominae-contaminated feces. It is considered a neglected tropical disease that affects 6 to 7 million people worldwide. The reactivation of Chagas disease occurs when the chronically infected hosts are not able to control T. cruzi infection, generating recurrence of the acute phase. HIV is the main immunosuppressive infection that can lead to the reactivation of chronic Chagas disease in AIDS conditions. In co-infected patients, the reactivation of Chagas disease is related to their high parasite load, high HIV viral load, and CD4 T-cell counting less than 200/mm³, which may evolve to meningoencephalitis and myocarditis. Eight T. cruzi/HIV co-infected patients under antiretroviral therapy (ART) and ten Chagas disease patients without HIV infection that attended at Study Group of Chagas Disease, Hospital de Clínicas, University of Campinas (GEdoCh/HC/UNICAMP-SP) and Pontifical Catholic University of Campinas SP (PUCC/SP) were evaluated. Tests for Chagas disease were performed, such as qPCR and T. cruzi blood culture. The patient’s medical records were analyzed to verify clinical and epidemiological data, viral load, and CD4 T-cell counting since the outset of ART. For both groups, we found no statically significant differences between parasite load via blood culture and qPCR. In T. cruzi/HIV co-infected subjects, we observed a significant increase of CD4 T-cells counting and viral load decrease, which became undetectable over the years after ART. Parasites isolated from the patient’s blood culture were genotyped, being the majority of them infected with TcII and one case of mixed infection (TcII and TcV/TcVI). These results were expected according to the region of origin of the patients. We suggest that the parasite load be monitored through qPCR in T.cruzi/HIV co-infected patients. We conclude that ART in people living with HIV improves infection and immunosuppression control, enabling the natural evolution of the American trypanosomiasis.     

Patient-level interventions to reduce alcohol-related harms in low- and middle-income countries: A systematic review and meta-summary

BackgroundDisease and disability from alcohol use disproportionately impact people in low- and middle-income countries (LMICs). While varied interventions have been shown to reduce alcohol use in high-income countries, their efficacy in LMICs has not been assessed. This systematic review describes current published literature on patient-level alcohol interventions in LMICs and specifically describes clinical trials evaluating interventions to reduce alcohol use in LMICs.Methods and findingsIn accordance with PRISMA, we performed a systematic review using an electronic search strategy from January 1, 1995 to December 1, 2020. Title, abstract, as well as full-text screening and extraction were performed in duplicate. A meta-summary was performed on randomized controlled trials (RCTs) that evaluated alcohol-related outcomes. We searched the following electronic databases: PubMed, EMBASE, Scopus, Web of Science, Cochrane, WHO Global Health Library, and PsycINFO. Articles that evaluated patient-level interventions targeting alcohol use and alcohol-related harm in LMICs were eligible for inclusion. No studies were excluded based on language.After screening 5,036 articles, 117 articles fit our inclusion criteria, 75 of which were RCTs. Of these RCTs, 93% were performed in 13 middle-income countries, while 7% were from 2 low-income countries. These RCTs evaluated brief interventions (24, defined as any intervention ranging from advice to counseling, lasting less than 1 hour per session up to 4 sessions), psychotherapy or counseling (15, defined as an interaction with a counselor longer than a brief intervention or that included a psychotherapeutic component), health promotion and education (20, defined as an intervention encouraged individuals’ agency of taking care of their health), or biologic treatments (19, defined as interventions where the biological function of alcohol use disorder (AUD) as the main nexus of intervention) with 3 mixing categories of intervention types. Due to high heterogeneity of intervention types, outcome measures, and follow-up times, we did not conduct meta-analysis to compare and contrast studies, but created a meta-summary of all 75 RCT studies. The most commonly evaluated intervention with the most consistent positive effect was a brief intervention; similarly, motivational interviewing (MI) techniques were most commonly utilized among the diverse array of interventions evaluated.ConclusionsOur review demonstrated numerous patient-level interventions that have the potential to be effective in LMICs, but further research to standardize interventions, populations, and outcome measures is necessary to accurately assess their effectiveness. Brief interventions and MI techniques were the most commonly evaluated and had the most consistent positive effect on alcohol-related outcomes.Trial registrationProtocol Registry: PROSPERO CRD42017055549

Catherine Staton and co-workers report on evidence about interventions against harmful alcohol use in low- and middle-income countries.     

Disease‐linked TDP‐43 hyperphosphorylation suppresses TDP‐43 condensation and aggregation

Post‐translational modifications (PTMs) have emerged as key modulators of protein phase separation and have been linked to protein aggregation in neurodegenerative disorders. The major aggregating protein in amyotrophic lateral sclerosis and frontotemporal dementia, the RNA‐binding protein TAR DNA‐binding protein (TDP‐43), is hyperphosphorylated in disease on several C‐terminal serine residues, a process generally believed to promote TDP‐43 aggregation. Here, we however find that Casein kinase 1δ‐mediated TDP‐43 hyperphosphorylation or C‐terminal phosphomimetic mutations reduce TDP‐43 phase separation and aggregation, and instead render TDP‐43 condensates more liquid‐like and dynamic. Multi‐scale molecular dynamics simulations reveal reduced homotypic interactions of TDP‐43 low‐complexity domains through enhanced solvation of phosphomimetic residues. Cellular experiments show that phosphomimetic substitutions do not affect nuclear import or RNA regulatory functions of TDP‐43, but suppress accumulation of TDP‐43 in membrane‐less organelles and promote its solubility in neurons. We speculate that TDP‐43 hyperphosphorylation may be a protective cellular response to counteract TDP‐43 aggregation.     

Increased runs of homozygosity in the autosomal genome of Brazilian individuals with neurodevelopmental delay/intellectual disability and/or multiple congenital anomalies investigated by chromosomal microarray analysis

Runs of homozygosity (ROH) in the human genome may be clinically relevant. The aim of this study was to report the frequency of increased ROH of the autosomal genome in individuals with neurodevelopmental delay/intellectual disability and/or multiple congenital anomalies, and to compare these data with a control group. Data consisted of calls of homozygosity from 265 patients and 289 controls. In total, 7.2% (19/265) of the patients showed multiple ROH exceeding 1% of autosomal genome, compared to 1.4% (4/289) in the control group (p=0.0006). Homozygosity ranged from 1.38% to 22.12% among patients, and from 1.53 to 2.40% in the control group. In turn, 1.9% (5/265) of patients presented ROH ≥10Mb in a single chromosome, compared to 0.3% (1/289) of individuals from the control group (p=0.0801). By excluding cases with reported consanguineous parents (15/24), the frequency of increased ROH was 3.4% (9/250) among patients and 1.7% (5/289) in the control group, considering multiple ROH exceeding 1% of the autosome genome and ROH ≥10Mb in a single chromosome together, although not statistically significant (p=0.1873). These results reinforce the importance of investigating ROH, which with complementary diagnostic tests can improve the diagnostic yield for patients with such conditions.     

Utilization of acetonitrile and other aliphatic nitriles by a Candida famata strain

Abstract A variant of a yeast strain identified as Candida famata isolated from gold mine effluent was able to grow on acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, methacrylnitrile, propionitrile, succinonitrile, valeronitrile, acetamide, isobutyamide, and succinamide as sole nitrogen source, after acclimatization. The yeast grew on acetonitrile and acetamide at concentrations up to 4%. The utilisation of acetonitrile and acetamide by the C. famata strain probably involves hydrolysis in a two-step reaction mediated by both inducible and intracellular nitrile hydratase and amidase.     

Microtubule cytoskeleton and morphogenesis in the amoebae of the myxomycete Physarum polycephalum

Summary— The amoebae of the myxomycete Physarum polycephalum are of interest in order to analyze the morphogenesis of the microtubule and microfilament cytoskeleton during cell cycle and flagellation. The amoebal interphase microtubule cytoskeleton consists of 2 distinct levels of organization, which correspond to different physiological roles. The first level is composed of the 2 kinetosomes or centrioles and their associated structures. The anterior and posterior kinetosomes forming the anterior and posterior flagella are morphologically distinguishable. Each centriole plays a role in the morphogenesis of its associated satellites and specific microtubule arrays. The 2 distinct centrioles correspond to the 2 successive maturation stages of the pro-centrioles which are built during prophase. The second level of organization consists of a prominent microtubule organizing center (mtoc 1) to which the anterior centriole is attached at least during interphase. This mtoc plays a role in the formation of the mitotic pole. These observations based on ultrastructural and physiological analyses of the amoebal cystoskeleton are now being extended to the biochemical level. The complex formed by the 2 centrioles and the mtoc 1 has been purified without modifying the microtubule-nucleating activity of the mtoc 1. Several microtubule-associated proteins have been characterized by their ability to bind taxol-stabilized microtubules. Their functions (e.g., microtubule assembly, protection of microtubules against dilution or cold treatment, phosphorylating and ATPase activities) are under investigation. These biochemical approaches could allow in vitro analysis of the morphogenesis of the amoebal microtubule cytoskeleton.