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Background: Chikungunya virus (CHIKV) infection induces arthralgia. The involvement of inflammatory cytokines and chemokines has been suggested, but very little is known about their secretion profile in CHIKV-infected patients.Methods: A case-control longitudinal study was performed that involved 30 adult patients with laboratory-confirmed Chikungunya fever. Their profiles of clinical disease, viral load, and immune mediators were investigated.Results: When patients were segregated into high viral load and low viral load groups during the acute phase, those with high viremia had lymphopenia, lower levels of monocytes, neutrophilia, and signs of inflammation. The high viral load group was also characterized by a higher production of pro-inflammatory cytokines, such as interferon-α and interleukin (IL)-6, during the acute phase. As the disease progressed to the chronic phase, IL-17 became detectable. However, persistent arthralgia was associated with higher levels of IL-6 and granulocyte macrophage colony-stimulating factor, whereas patients who recovered fully had high levels of Eotaxin and hepatocyte growth factor.Conclusions: The level of CHIKV viremia during the acute phase determined specific patterns of pro-inflammatory cytokines, which were associated with disease severity. At the chronic phase, levels of IL-6, and granulocyte macrophage colony-stimulating factor found to be associated with persistent arthralgia provide a possible explanation for the etiology of arthralgia that plagues numerous CHIKV-infected patients. [ABSTRACT FROM AUTHOR]

Given the increasing aging population and the rising prevalence of musculoskeletal diseases due to obesity and injury, urgent research is needed to formulate new treatment alternatives, as current options remain inadequate. Viruses can exacerbate arthritis and worsen symptoms in patients with pre-existing osteoarthritis. Over the past decade, the chikungunya virus (CHIKV) has emerged as a significant public health concern, especially in Asia and South America. Exploring natural products, such as berberine, has shown promise due to its anticatabolic, antioxidative, and anti-inflammatory effects. However, berberine's low stability and bioavailability limit its efficacy. We hypothesized that encapsulating berberine into a proniosome gel, known for its ease of preparation and stability, could enhance its bioavailability and efficacy when applied topically, potentially treating CHIKV infection. Our investigation focused on how varying berberine loads and selected excipients in the proniosome gel influenced its physical properties, stability, and skin permeability. We also examined the biological half-life of berberine in plasma upon topical administration in mice to assess the potential for controlled and sustained drug release. Additionally, we analyzed the antioxidant stress activity and cell viability of HaCaT keratinocytes and developed a lipopolysaccharide-stimulated cell culture model to evaluate anti-inflammatory effects using pro-inflammatory cytokines. Overall, the research aims to transform the treatment landscape for arthritis by leveraging berberine's therapeutic potential.

Fiber-reinforced composites are among the recognized competing materials in various engineering applications. Ramie and pineapple leaf fibers are fascinating natural fibers due to their remarkable material properties. This research study aims to unveil the viability of hybridizing two kinds of lignocellulosic plant fiber fabrics in polymer composites. In this work, the hybrid composites were prepared with the aid of the hot compression technique. The mechanical, water-absorbing, and thickness swelling properties of ramie and pineapple leaf fiber fabric-reinforced polypropylene hybrid composites were identified. A comparison was made between non-hybrid and hybrid composites to demonstrate the hybridization effect. According to the findings, hybrid composites, particularly those containing ramie fiber as a skin layer, showed a prominent increase in mechanical strength. In comparison with non-hybrid pineapple leaf fabric-reinforced composites, the tensile, flexural, and Charpy impact strengths were enhanced by 52.10%, 18.78%, and 166.60%, respectively, when the outermost pineapple leaf fiber layers were superseded with ramie fabric. However, increasing the pineapple leaf fiber content reduced the water absorption and thickness swelling of the hybrid composites. Undeniably, these findings highlight the potential of hybrid composites to reach a balance in mechanical properties and water absorption while possessing eco-friendly characteristics.

Communications between immune cells are essential to ensure appropriate coordination of their activities. Here, we observed the infiltration of activated macrophages into the joint-footpads of chikungunya virus (CHIKV)-infected animals. Large numbers of CD64 + MHCII + and CD64 + MHCII - macrophages were present in the joint-footpad, preceded by the recruitment of their CD11b + Ly6C + inflammatory monocyte precursors. Recruitment and differentiation of these myeloid subsets were dependent on CD4 + T cells and GM-CSF. Transcriptomic and gene ontology analyses of CD64 + MHCII + and CD64 + MHCII - macrophages revealed 89 differentially expressed genes, including genes involved in T cell proliferation and differentiation pathways. Depletion of phagocytes, including CD64 + MHCII + macrophages, from CHIKV-infected mice reduced disease pathology, demonstrating that these cells play a pro-inflammatory role in CHIKV infection. Together, these results highlight the synergistic dynamics of immune cell crosstalk in driving CHIKV immunopathogenesis. This study provides new insights in the disease mechanism and offers opportunities for development of novel anti-CHIKV therapeutics., (© 2024. The Author(s).)

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused more than 700 million confirmed infections and ~7 million fatalities worldwide since its emergence in December 2019. SARS-CoV-2 is part of a family of positive-sense, enveloped RNA viruses known as coronaviruses. Today, at least seven human coronaviruses have been identified and are known to cause respiratory tract illnesses with varying severity. The COVID-19 pandemic spurred the generation of a vast amount of scientific knowledge on coronaviruses in record time, leading to a broad understanding of host immunity against SARS-CoV-2, and the rapid development of life-saving vaccines (mainly mRNA and adenovirus- or inactivated virus-based vaccines). Real world data on licensed SARS-CoV-2 vaccines have shown that efficacy ranges from 50 to 95% depending on viral variants, pre-infections, and vaccine formulations, regimens, and combinations. While vaccination does markedly decrease the chances of infection and severe disease, breakthrough symptomatic and asymptomatic infections have occurred due to the emergence of immune escape virus variants. Therefore, despite these early successes, a better understanding of the mechanisms of protective immunity against infection is essential for the development of longer lasting and more efficient vaccines against SARS-CoV-2 and future coronaviruses., (© 2023 The Authors. Published under the terms of the CC BY 4.0 license.)

Objective: Despite the high vaccine efficacy of mRNA COVID-19 vaccines, there are individuals who developed excessive reactogenic and/or allergic responses after the first mRNA dose and were considered ineligible for further mRNA doses. CoronaVac, an inactivated SARS-CoV-2 vaccine, is recommended in Singapore as an alternative., Methods: Individuals, ineligible for further mRNA vaccines (BNT162b2 or mRNA-1273) because of excessive reactive responses to prime mRNA vaccination, were recruited and offered two doses of CoronaVac as booster vaccination 38-224 days post their mRNA vaccine dose. Individuals who did not develop any excessive reactive responses after the prime mRNA vaccination were also recruited and given another mRNA vaccine as booster vaccination. Blood samples were collected at days 0, 21 and 90 post first CoronaVac dose and mRNA dose, respectively, for analysis., Results: We showed that two CoronaVac booster doses induced specific immunity in these mRNA vaccine-primed individuals. Although the spike-specific antibody response was lower, their memory B cell response against the receptor-binding domain (RBD) of the spike protein was similar, compared with individuals who received two BNT162b2 injections. The spike-specific memory T cell response also increased following CoronaVac booster doses. However, specific immunity against the Omicron variant was low, similar to individuals with two BNT162b2 doses., Conclusion: Our findings showed that while mRNA vaccine-primed individuals can opt for two subsequent doses of CoronaVac, an additional dose may be necessary to achieve protection, especially against newly emerging immune escape variants such as Omicron., Competing Interests: A patent application for the SFB assay has been filed (Singapore patent #10202009679P: A Method Of Detecting Antibodies And Related Products). The authors declare no other competing interests., (© 2022 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Complexity is a fundamental feature of biological systems. Omics techniques like lipidomics can simultaneously quantify many thousands of molecules, thereby directly capturing the underlying biological complexity. However, this approach transfers the original biological complexity to the resulting datasets, posing challenges in data reduction and analysis. Aging is a prime example of a process that exhibits complex behaviour across multiple scales of biological organisation. The aging process is characterised by slow, cumulative and detrimental changes that are driven by intrinsic biological stochasticity and mediated through non-linear interactions and feedback within and between these levels of organization (ranging from metabolites, macromolecules, organelles and cells to tissue and organs). Only collectively and over long timeframes do these changes manifest as the exponential increases in morbidity and mortality that define biological aging, making aging a problem more difficult to study than the aetiologies of specific diseases. But aging's time dependence can also be exploited to extract key insights into its underlying biology. Here we explore this idea by using data on changes in lipid composition across the lifespan of an organism to construct and test a LipidClock to predict biological age in the nematode Caenorhabdits elegans . The LipidClock consist of a feature transformation via Principal Component Analysis followed by Elastic Net regression and yields and Mean Absolute Error of 1.45 days for wild type animals and 4.13 days when applied to mutant strains with lifespans that are substantially different from that of wild type. Gompertz aging rates predicted by the LipidClock can be used to simulate survival curves that are in agreement with those from lifespan experiments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Unfried, Ng, Cazenave-Gassiot, Batchu, Kennedy, Wenk, Tolwinski and Gruber.)

Objectives: Immunopathology of ongoing COVID-19 global pandemic is not limited solely to pulmonary tissue, but is often associated with multi-organ complications, mechanisms of which are intensely being investigated. In this regard, the interplay between immune, stromal cells and cytokines in pulmonary and extrapulmonary infected tissues, especially in young adults (median age 46 years, range 30-53 years) without comorbidities, remains poorly characterised., Methods: We profiled lung, heart and intestinal autopsy samples from five SARS-CoV-2-infected cases for 18-20 targets to detect immune, cytokine and stromal cell status at subcellular resolution by a novel IHC-based deep-phenotyping technique, iSPOT (immunoSpatial histoPhenOmics using TSA-IHC), to assess spatial and functional patterns of immune response in situ , in lethal COVID-19 infection., Results: SARS-CoV-2-infected autopsy samples exhibit skewed counts of immune populations in all samples with organ-specific dysfunctions. Lung and ileal tissue reveal altered architecture with marked loss of tissue integrity, while lung and heart tissue show severe hyperinflammation marked by elevated TNF-α in heart tissue and additionally IL-6, IFN-γ and IL-10 cytokines in lung samples., Conclusion: With resurgence of infection in younger populations, single-cell cytokine localisation in immune and stromal structures provides important mechanistic insights into organ-specific immunopathology of naïve SARS-CoV-2 infection in the absence of other comorbidities., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Reduced glutathione (GSH) plays an essential role in relieving oxidative insult from the generation of free radicals via normal physiological processes. However, GSH can be exploited by bacteria as a signalling molecule for the regulation of virulence. We describe findings arising from a serendipitous observation that when GSH and Escherichia coli were incubated with 5'fluorodeoxyuridine (FUdR)-synchronised populations of Caenorhabditis elegans, the nematodes underwent rapid death. Death was mediated by the production of hydrogen sulphide mainly through the action of tnaA, a tryptophanase-encoding gene in E. coli. Other Enterobacteriaceae species possess similar cysteine desulfhydrases that can catabolise l-cysteine-containing compounds to hydrogen sulphide and mediate nematode killing when worms had been pre-treated with FUdR. When colonic epithelial cell lines were infected, hydrogen sulphide produced by these bacteria in the presence of GSH was also able to inhibit ATP synthesis in these cells particularly when cells had been treated with FUdR. Therefore, bacterial production of hydrogen sulphide could act in concert with a commonly used genotoxic cancer drug to exert host cell impairment. Hydrogen sulphide also increases bacterial adhesion to the intestinal cells. These findings could have implications for patients undergoing chemotherapy using FUdR analogues that could result in intestinal damage., (© 2022 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

In populations around the world, the fraction of humans aged 65 and above is increasing at an unprecedented rate. Aging is the main risk factor for the most important degenerative diseases and this demographic shift poses significant social, economic, and medical challenges. Pharmacological interventions directly targeting mechanisms of aging are an emerging strategy to delay or prevent age-dependent diseases. Successful application of this approach has the potential to yield dramatic health, social, and economic benefits. Psora-4 is an inhibitor of the voltage-gated potassium channel, Kv1.3, that has previously been shown to increase longevity and health span in the nematode Caenorhabditis elegans (C. elegans). Our recent discovery that Psora-4 lifespan benefits in C. elegans are synergistic with those of several other lifespan-extending drugs has motivated us to investigate further the mechanism by which Psora-4 extends lifespan. Here, we report that Psora-4 increases the production of free radicals and modulates genes related to stress response and that its effect intersects closely with the target set of caloric restriction (CR) genes, suggesting that it, in part, acts as CR mimetic. This effect may be related to the role of potassium channels in energy metabolism. Our discovery of a potassium channel blocker as a CR mimetic suggests a novel avenue for mimicking CR and extending a healthy lifespan., (© 2021. American Aging Association.)

The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor-binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1β and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

O'nyongnyong virus (ONNV) is a re-emerging alphavirus previously known to be transmitted by main malaria vectors, thus suggesting the possibility of coinfections with arboviruses in co-endemic areas. However, the pathological outcomes of such infections remain unknown. Using murine coinfection models, we demonstrated that a preexisting blood-stage Plasmodium infection suppresses ONNV-induced pathologies. We further showed that suppression of viremia and virus dissemination are dependent on Plasmodium -induced IFNγ and are associated with reduced infection of CD45 - cells at the site of virus inoculation. We further proved that treatment with IFNγ or plasma samples from Plasmodium vivax -infected patients containing IFNγ are able to restrict ONNV infection in human fibroblast, synoviocyte, skeletal muscle, and endothelial cell lines. Mechanistically, the role of IFNγ in restricting ONNV infection was confirmed in in vitro infection assays through the generation of an IFNγ receptor 1 α chain (IFNγR1)-deficient cell line., (© 2022 Torres-Ruesta et al.)

Many organs and tissues have an intrinsic ability to regenerate from a dedicated, tissue-specific stem cell pool. As organisms age, the process of self-regulation or homeostasis begins to slow down with fewer stem cells available for tissue repair. Tissues become more fragile and organs less efficient. This slowdown of homeostatic processes leads to the development of cellular and neurodegenerative diseases. In this review, we highlight the recent use and future potential of optogenetic approaches to study homeostasis. Optogenetics uses photosensitive molecules and genetic engineering to modulate cellular activity in vivo, allowing precise experiments with spatiotemporal control. We look at applications of this technology for understanding the mechanisms governing homeostasis and degeneration as applied to widely used model organisms, such as Drosophila melanogaster, where other common tools are less effective or unavailable., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: Host determinants of severe coronavirus disease 2019 include advanced age, comorbidities and male sex. Virologic factors may also be important in determining clinical outcome and transmission rates, but limited patient-level data is available., Methods: We conducted an observational cohort study at seven public hospitals in Singapore. Clinical and laboratory data were collected and compared between individuals infected with different SARS-CoV-2 clades. Firth's logistic regression was used to examine the association between SARS-CoV-2 clade and development of hypoxia, and quasi-Poisson regression to compare transmission rates. Plasma samples were tested for immune mediator levels and the kinetics of viral replication in cell culture were compared., Findings: 319 patients with PCR-confirmed SARS-CoV-2 infection had clinical and virologic data available for analysis. 29 (9%) were infected with clade S, 90 (28%) with clade L/V, 96 (30%) with clade G (containing D614G variant), and 104 (33%) with other clades 'O' were assigned to lineage B.6. After adjusting for age and other covariates, infections with clade S (adjusted odds ratio (aOR) 0·030 (95% confidence intervals (CI): 0·0002-0·29)) or clade O (B·6) (aOR 0·26 (95% CI 0·064-0·93)) were associated with lower odds of developing hypoxia requiring supplemental oxygen compared with clade L/V. Patients infected with clade L/V had more pronounced systemic inflammation with higher concentrations of pro-inflammatory cytokines, chemokines and growth factors. No significant difference in the severity of clade G infections was observed (aOR 0·95 (95% CI: 0·35-2·52). Though viral loads were significantly higher, there was no evidence of increased transmissibility of clade G, and replicative fitness in cell culture was similar for all clades., Interpretation: Infection with clades L/V was associated with increased severity and more systemic release of pro-inflammatory cytokines. Infection with clade G was not associated with changes in severity, and despite higher viral loads there was no evidence of increased transmissibility., Competing Interests: Declaration of Competing Interest BY has received honoraria from Sanofi and Roche, outside the submitted work. All other authors no conflicts of interest declared., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Numerous reports of vascular events after an initial recovery from COVID-19 form our impetus to investigate the impact of COVID-19 on vascular health of recovered patients. We found elevated levels of circulating endothelial cells (CECs), a biomarker of vascular injury, in COVID-19 convalescents compared to healthy controls. In particular, those with pre-existing conditions (e.g., hypertension, diabetes) had more pronounced endothelial activation hallmarks than non-COVID-19 patients with matched cardiovascular risk. Several proinflammatory and activated T lymphocyte-associated cytokines sustained from acute infection to recovery phase, which correlated positively with CEC measures, implicating cytokine-driven endothelial dysfunction. Notably, we found higher frequency of effector T cells in our COVID-19 convalescents compared to healthy controls. The activation markers detected on CECs mapped to counter receptors found primarily on cytotoxic CD8 + T cells, raising the possibility of cytotoxic effector cells targeting activated endothelial cells. Clinical trials in preventive therapy for post-COVID-19 vascular complications may be needed., Competing Interests: FC, SF, KW, AS, SK, YC, GC, LT, FG, RT, LZ, AK, ST, LR, LN, DL, CC No competing interests declared, BY Barnaby E. Young declares no direct competing interests with this work, but has received honoraria outside this work from Sanofi and Roche. PT Paul A. Tambyah declares no direct competing interests with this work but has received research support outside this work from Roche, Sanofi-Pasteur, Johnson and Johnson, AJ Biologicals and Shionogi., (© 2021, Chioh et al.)

Objectives: The emergence of a SARS-CoV-2 variant with a point mutation in the spike (S) protein, D614G, has taken precedence over the original Wuhan isolate by May 2020. With an increased infection and transmission rate, it is imperative to determine whether antibodies induced against the D614 isolate may cross-neutralise against the G614 variant., Methods: Antibody profiling against the SARS-CoV-2 S protein of the D614 variant by flow cytometry and assessment of neutralising antibody titres using pseudotyped lentiviruses expressing the SARS-CoV-2 S protein of either the D614 or G614 variant tagged with a luciferase reporter were performed on plasma samples from COVID-19 patients with known D614G status ( n  = 44 infected with D614, n  = 6 infected with G614, n  = 7 containing all other clades: O, S, L, V, G, GH or GR)., Results: Profiling of the anti-SARS-CoV-2 humoral immunity reveals similar neutralisation profiles against both S protein variants, albeit waning neutralising antibody capacity at the later phase of infection. Of clinical importance, patients infected with either the D614 or G614 clade elicited a similar degree of neutralisation against both pseudoviruses, suggesting that the D614G mutation does not impact the neutralisation capacity of the elicited antibodies., Conclusions: Cross-reactivity occurs at the functional level of the humoral response on both the S protein variants, which suggests that existing serological assays will be able to detect both D614 and G614 clades of SARS-CoV-2. More importantly, there should be negligible impact towards the efficacy of antibody-based therapies and vaccines that are currently being developed., Competing Interests: All authors declare no conflicts., (© 2021 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Aging animals accumulate insoluble proteins as a consequence of a decline of proteostatic maintenance with age. In Caenorhabditis elegans, for instance, levels of detergent-insoluble proteins increase with age. In longer-lived strains of C. elegans, this accumulation occurs more slowly, implying a link to lifespan determination. We further explored this link and found that detergent-insoluble proteins accumulate more rapidly at higher temperatures, a condition where lifespan is short. We employed a C. elegans strain carrying a GFP transcriptional reporter under the control of a heat shock (hsp-16.2) promoter to investigate the dynamics of proteostatic failure in individual nematodes. We found that early, sporadic activation of hsp-16.2 was predictive of shorter remaining lifespan in individual nematodes. Exposure to rapamycin, resulting in reduced mTOR signaling, delayed spurious expression, extended lifespan, and delayed accumulation of insoluble proteins, suggesting that targets downstream of the mTOR pathway regulate the accumulation of insoluble proteins. We specifically explored ribosomal S6 kinase (rsks-1) as one such candidate and found that RNAi against rsks-1 also resulted in less age-dependent accumulation of insoluble proteins and extended lifespan. Our results demonstrate that inhibition of protein translation via reduced mTOR signaling resulted in slower accumulation of insoluble proteins, delayed proteostatic crisis, and extended lifespan in C. elegans.

SARS-CoV-2 is the novel coronavirus responsible for the current COVID-19 pandemic. Severe complications are observed only in a small proportion of infected patients but the cellular mechanisms underlying this progression are still unknown. Comprehensive flow cytometry of whole blood samples from 54 COVID-19 patients reveals a dramatic increase in the number of immature neutrophils. This increase strongly correlates with disease severity and is associated with elevated IL-6 and IP-10 levels, two key players in the cytokine storm. The most pronounced decrease in cell counts is observed for CD8 T-cells and VD2 γδ T-cells, which both exhibit increased differentiation and activation. ROC analysis reveals that the count ratio of immature neutrophils to VD2 (or CD8) T-cells predicts pneumonia onset (0.9071) as well as hypoxia onset (0.8908) with high sensitivity and specificity. It would thus be a useful prognostic marker for preventive patient management and improved healthcare resource management.

Objectives: Little is known about the prevalence of febrile illness in the Arabian region as clinical, laboratory and immunological profiling remains largely uncharacterised., Methods: A total of 2018 febrile patients from Jazan, Saudi Arabia, were recruited between 2014 and 2017. Patients were screened for dengue and chikungunya virus, Plasmodium , Brucella , Neisseria meningitidis , group A streptococcus and Leptospira . Clinical history and biochemical parameters from blood tests were collected. Patient sera of selected disease-confirmed infections were quantified for immune mediators by multiplex microbead-based immunoassays., Results: Approximately 20% of febrile patients were tested positive for one of the pathogens, and they presented overlapping clinical and laboratory parameters. Nonetheless, eight disease-specific immune mediators were identified as potential biomarkers for dengue (MIP-1α, MCP-1), malaria (TNF-α), streptococcal and meningococcal (eotaxin, GRO-α, RANTES, SDF-1α and PIGF-1) infections, with high specificity and sensitivity profiles. Notably, based on the conditional inference model, six of these mediators (MIP-1α, TNF-α, GRO-α, RANTES, SDF-1α and PIGF-1) were revealed to be 68.4% accurate in diagnosing different febrile infections, including those of unknown diseases., Conclusions: This study is the first extensive characterisation of the clinical analysis and immune biomarkers of several clinically important febrile infections in Saudi Arabia. Importantly, an immune signature with robust accuracy, specificity and sensitivity in differentiating several febrile infections was identified, providing useful insights into patient disease management in the Arabian Peninsula., Competing Interests: The authors declare no conflict of interests. 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J Clin Invest2020; 130: 2620–2629.3221783554KamY‐W, LeiteJA, LumF‐Met alSpecific biomarkers associated with neurological complications and congenital central nervous system abnormalities from Zika virus‐infected patients in Brazil. J Infect Dis2017; 216: 172–181.28838147, (© 2020 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian New Zealand Society for Immunology, Inc.)

Objectives: A wide range of duration of viral RNA shedding in patients infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been observed. We aimed to investigate factors associated with prolonged and intermittent viral RNA shedding in a retrospective cohort of symptomatic COVID-19 patients., Methods: Demographic, clinical and laboratory data from hospitalised COVID-19 patients from a single centre with two consecutive negative respiratory reverse transcription-polymerase chain reaction (RT-PCR) results were extracted from electronic medical records. Kaplan-Meier survival curve analysis was used to assess the effect of clinical characteristics on the duration and pattern of shedding. Plasma levels of immune mediators were measured using Luminex multiplex microbead-based immunoassay., Results: There were 201 symptomatic patients included. Median age was 49 years (interquartile range 16-61), and 52.2% were male. Median RNA shedding was 14 days (IQR 9-18). Intermittent shedding was observed in 77 (38.3%). We did not identify any factor associated with prolonged or intermittent viral RNA shedding. Duration of shedding was inversely correlated with plasma levels of T-cell cytokines IL-1β and IL-17A at the initial phase of infection, and patients had lower levels of pro-inflammatory cytokines during intermittent shedding., Conclusions: Less active T-cell responses at the initial phase of infection were associated with prolonged viral RNA shedding, suggesting that early immune responses are beneficial to control viral load and prevent viral RNA shedding. Intermittent shedding is common and may explain re-detection of viral RNA in recovered patients., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Objectives: While the safety of non-steroidal anti-inflammatory drugs in COVID-19 has been questioned, they may be beneficial given the hyper-inflammatory immune response associated with severe disease. We aimed to assess the safety and potential efficacy of cyclooxygenase-2 (COX-2) selective inhibitors in high-risk patients., Methods: Retrospective study of patients with COVID-19 pneumonia and aged ≥ 50 years who were admitted to hospital. Adverse outcomes analysed included supplemental oxygen use, intensive care unit admission, mechanical ventilation and mortality, with the primary endpoint a composite of any of these. Plasma levels of inflammatory cytokines and chemokines were measured in a subset., Results: Twenty-two of 168 (13.1%) in the cohort received COX-2 inhibitors [median duration 3 days, interquartile range (IQR) 3-4.25]. Median age was 61 (IQR 55-67.75), 44.6% were female, and 72.6% had at least one comorbidity. A lower proportion of patients receiving COX-2 inhibitors met the primary endpoint: 4 (18.2%) versus 57 (39.0%), P  = 0.062. This difference was less pronounced after adjusting for baseline difference in age, gender and comorbidities in a multivariate logistic regression model [adjusted odds ratio (AOR) 0.45, 95% CI 0.14-1.46]. The level of interleukin-6 declined after treatment in five of six (83.3%) treatment group patients [compared to 15 of 28 (53.6%) in the control group] with a greater reduction in absolute IL-6 levels ( P -value = 0.025)., Conclusion: Treatment with COX-2 inhibitors was not associated with an increase in adverse outcomes. Its potential for therapeutic use as an immune modulator warrants further evaluation in a large randomised controlled trial., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Caloric restriction (CR) is one of the most effective interventions to prolong lifespan and promote health. Recently, it has been suggested that hydrogen sulfide (H 2 S) may play a pivotal role in mediating some of these CR-associated benefits. While toxic at high concentrations, H 2 S at lower concentrations can be biologically advantageous. H 2 S levels can be artificially elevated via H 2 S-releasing donor drugs. In this study, we explored the function of a novel, slow-releasing H 2 S donor drug (FW1256) and used it as a tool to investigate H 2 S in the context of CR and as a potential CR mimetic. We show that exposure to FW1256 extends lifespan and promotes health in Caenorhabditis elegans ( C. elegans ) more robustly than some previous H 2 S-releasing compounds, including GYY4137. We looked at the extent to which FW1256 reproduces CR-associated physiological effects in normal-feeding C. elegans . We found that FW1256 promoted healthy longevity to a similar degree as CR but with fewer fitness costs. In contrast to CR, FW1256 actually enhanced overall reproductive capacity and did not reduce adult body length. FW1256 further extended the lifespan of already long-lived eat-2 mutants without further detriments in developmental timing or fertility, but these lifespan and healthspan benefits required H 2 S exposure to begin early in development. Taken together, these observations suggest that FW1256 delivers exogenous H 2 S efficiently and supports a role for H 2 S in mediating longevity benefits of CR. Delivery of H 2 S via FW1256, however, does not mimic CR perfectly, suggesting that the role of H 2 S in CR-associated longevity is likely more complex than previously described., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2020.)

Objectives: Zika virus (ZIKV) is a mosquito-borne flavivirus that re-emerged in 2015. The association between ZIKV and neurological complications initiated the development of relevant animal models to understand the mechanisms underlying ZIKV-induced pathologies. Transient inhibition of the type I interferon (IFN) pathway through the use of an IFNAR1-blocking antibody, MAR1-5A3, could efficiently permit active virus replication in immunocompetent animals. Type I IFN signalling is involved in the regulation of humoral responses, and thus, it is crucial to investigate the potential effects of type I IFN blockade towards B-cell responses., Methods: In this study, comparative analysis was conducted using serum samples collected from ZIKV-infected wild-type (WT) animals either administered with or without MAR1-5A3., Results: Serological assays revealed a more robust ZIKV-specific IgG response and subtype switching upon inhibition of type I IFN due to the abundance of antigen availability. This observation was corroborated by an increase in germinal centres, plasma cells and germinal centre B cells. Interestingly, although both groups of animals recognised different B-cell linear epitopes in the E and NS1 regions, there was no difference in neutralising capacity. Further characterisation of these epitopes in the E protein revealed a detrimental role of antibodies that were generated in the absence of type I IFN., Conclusion: This study highlights the role of type I IFN in shaping the anti-ZIKV antibody response to generate beneficial antibodies and will help guide development of better vaccine candidates triggering efficient neutralising antibodies and avoiding detrimental ones., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology Inc.)

Objectives: Effects of Zika virus (ZIKV) infection on placental development during pregnancy are unclear., Methods: Full-term placentas from three women, each infected with ZIKV during specific pregnancy trimesters, were harvested for anatomic, immunologic and transcriptomic analysis., Results: In this study, each woman exhibited a unique immune response with raised IL-1RA, IP-10, EGF and RANTES expression and neutrophil numbers during the acute infection phase. Although ZIKV NS3 antigens co-localised to placental Hofbauer cells, the placentas showed no anatomic defects. Transcriptomic analysis of samples from the placentas revealed that infection during trimester 1 caused a disparate cellular response centred on differential eIF2 signalling, mitochondrial dysfunction and oxidative phosphorylation. Despite these, the babies were delivered without any congenital anomalies., Conclusion: These findings should translate to improve clinical prenatal screening procedures for virus-infected pregnant patients., Competing Interests: The authors declare no conflict of interest., (© 2019 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology Inc.)

Developmental signaling pathways control a vast array of biological processes during embryogenesis and in adult life. The WNT pathway was discovered simultaneously in cancer and development. Recent advances have expanded the role of WNT to a wide range of pathologies in humans. Here, we discuss the WNT pathway and its role in human disease and some of the advances in WNT-related treatments., Competing Interests: The authors declare no conflict of interest.

The abnormal accumulation of β-amyloid peptide (Aβ) is recognized as a central component in the pathogenesis of Alzheimer disease. While many aspects of Aβ-mediated neurotoxicity remain elusive, Aβ has been associated with numerous underlying pathologies, including oxidative and nitrosative stress, inflammation, metal ion imbalance, mitochondrial dysfunction, and even tau pathology. Ergothioneine (ET), a naturally occurring thiol/thione-derivative of histidine, has demonstrated antioxidant and neuroprotective properties against various oxidative and neurotoxic stressors. This study investigates ET's potential to counteract Aβ-toxicity in transgenic Caenorhabditis elegans overexpressing a human Aβ peptide. The accumulation of Aβ in this model leads to paralysis and premature death. We show that ET dose-dependently reduces Aβ-oligomerization and extends the lifespan and healthspan of the nematodes., (© 2019 Federation of European Biochemical Societies.)

Objectives: Recent Zika virus (ZIKV) outbreaks challenged existing laboratory diagnostic standards, especially for serology-based methods. Because of the genetic and structural similarity of ZIKV with other flaviviruses, this results in cross-reactive antibodies, which confounds serological interpretations., Methods: Plasma from Singapore ZIKV patients was screened longitudinally for antibody responses and neutralising capacities against ZIKV. Samples from healthy controls, ZIKV patients and DENV patients were further assessed using ZIKV and DENV peptides of precursor membrane (prM), envelope (E) or non-structural 1 (NS1) viral proteins in a peptide-based ELISA for epitope identification. Identified epitopes were re-validated and diagnostically evaluated using sera of patients with DENV, bacteria or unknown infections from Thailand., Results: Long-lasting ZIKV-neutralising antibodies were elicited during ZIKV infection. Thirteen potential linear B-cell epitopes were identified, and of these, four common flavivirus, three ZIKV-specific and one DENV-specific differential epitopes had more than 50% sensitivity and specificity. Notably, ZIKV-specific peptide 26 on domain I/II of E protein (amino acid residues 271-288) presented 80% sensitivity and 85.7% specificity. Importantly, the differential epitopes also showed significance in differentiating non-flavivirus patient samples., Conclusion: Linear B-cell epitope candidates to differentiate between ZIKV and DENV infections were identified, providing the first step towards the design of a much-needed serology-based assay., Competing Interests: The authors declare no conflict of interest.

Currently, there are no commercially available live-attenuated vaccines against chikungunya virus (CHIKV). Here, CHIKVs with mutations in non-structural proteins (nsPs) were investigated for their suitability as attenuated CHIKV vaccines. R532H mutation in nsP1 caused reduced infectivity in mouse tail fibroblasts but an enhanced type-I IFN response compared to WT-CHIKV Adult mice infected with this nsP-mutant exhibited a mild joint phenotype with low-level viremia that rapidly cleared. Mechanistically, ingenuity pathway analyses revealed a tilt in the anti-inflammatory IL-10 versus pro-inflammatory IL-1β and IL-18 balance during CHIKV nsP-mutant infection that modified acute antiviral and cell signaling canonical pathways. Challenging CHIKV nsP-mutant-infected mice with WT-CHIKV or the closely related O'nyong-nyong virus resulted in no detectable viremia, observable joint inflammation, or damage. Challenged mice showed high antibody titers with efficient neutralizing capacity, indicative of immunological memory. Manipulating molecular processes that govern CHIKV replication could lead to plausible vaccine candidates against alphavirus infection., (© 2019 Agency for Science, Technology and Research (A*STAR). Published under the terms of the CC BY 4.0 license.)

Mitochondrial function and dysfunction are at the core of aging and involved in many age-dependent diseases. Rate of oxygen consumption is a measure of mitochondrial function and energy production rate. The nematode Caenorhabditis elegans (C. elegans ) offers an opportunity to study "living" mitochondria without the need for mitochondrial extraction, purification and associated artifacts. Oxygen consumption rate (OCR) is traditionally measured using single-chamber Clark electrodes with or without the addition of metabolic modulators. More recently, multi-well oxygen electrodes with automated injection system have been developed to enable rapid measurement of OCR under different conditions. Here, we describe a detailed protocol that we have adapted from existing protocols to measure coupled and uncoupled mitochondrial respiration (with and without metabolic modulators) in live respiring nematodes using a Seahorse XFe96 extracellular flux analyzer. We present details on our protocol, including preparation of nematode culture, use of metabolic modulators, execution of Seahorse XF assay as well as post-experimental data analysis. As a reference, we provide results of a series of experiments in which the metabolic activity of N2 wild-type nematodes was compared to N2 nematode treated with paraquat, a compound that generates reactive oxygen species (ROS), thus causing oxidative damage and mitochondrial dysfunction. These data illustrate the kind of insights that can be obtained even using a low number of nematodes (10 animals only per well)., Competing Interests: Competing interestsThe authors declare that there are no conflicts of interest or competing interests., (Copyright © 2019 The Authors; exclusive licensee Bio-protocol LLC.)

The mitochondrial free radical theory of aging (mFRTA) proposes that accumulation of oxidative damage to macromolecules in mitochondria is a causative mechanism for aging. Accumulation of mitochondrial DNA (mtDNA) damage may be of particular interest in this context. While there is evidence for age-dependent accumulation of mtDNA damage, there have been only a limited number of investigations into mtDNA damage as a determinant of longevity. This lack of quantitative data regarding mtDNA damage is predominantly due to a lack of reliable assays to measure mtDNA damage. Here, we report adaptation of a quantitative real-time polymerase chain reaction (qRT-PCR) assay for the detection of sequence-specific mtDNA damage in C. elegans and apply this method to investigate the role of mtDNA damage in the aging of nematodes. We compare damage levels in old and young animals and also between wild-type animals and long-lived mutant strains or strains with modifications in ROS detoxification or production rates. We confirm an age-dependent increase in mtDNA damage levels in C. elegans but found that there is no simple relationship between mtDNA damage and lifespan. MtDNA damage levels were high in some mutants with long lifespan (and vice versa ). We next investigated mtDNA damage, lifespan and healthspan effects in nematode subjected to exogenously elevated damage (UV- or γ-radiation induced). We, again, observed a complex relationship between damage and lifespan in such animals. Despite causing a significant elevation in mtDNA damage, γ-radiation did not shorten the lifespan of nematodes at any of the doses tested. When mtDNA damage levels were elevated significantly using UV-radiation, nematodes did suffer from shorter lifespan at the higher end of exposure tested. However, surprisingly, we also found hormetic lifespan and healthspan benefits in nematodes treated with intermediate doses of UV-radiation, despite the fact that mtDNA damage in these animals was also significantly elevated. Our results suggest that within a wide physiological range, the level of mtDNA damage does not control lifespan in C. elegans .

Chikungunya virus (CHIKV) has been a worldwide threat since its reemergence in La Reunion Island in 2004. Expression of the interferon-stimulated protein Viperin correlates with viral load burden in patients, and studies in mice have demonstrated its role to limit disease severity against CHIKV infection. Using Viperin -/- mice, we aimed to understand the contribution of Viperin to the T-cell immune response against CHIKV. CD4 T-cell depletion in Viperin -/- mice showed that increased late acute joint inflammation (5-8 d postinfection) was exclusively mediated by T cells. Specifically, CHIKV-infected Viperin -/- mice showed an increased INFγ Th1 profile of CD4 T cells, enhanced INFγ stimulation by APCs, an increased INFγ secretion profile in the joint microenvironment, and increased numbers of inflammatory monocytes in virus-infected joints compared with WT mice. Bone marrow grafting experiments showed that Viperin expression in both hematopoietic and non-hematopoietic cells is instrumental in reducing disease severity associated with a CD4 T-cell response., (© 2019 Carissimo et al.)

There is growing interest in pharmacological interventions directly targeting the aging process. Pharmacological interventions against aging should be efficacious when started in adults and, ideally, repurpose existing drugs. We show that dramatic lifespan extension can be achieved by targeting multiple, evolutionarily conserved aging pathways and mechanisms using drug combinations. Using this approach in C. elegans, we were able to slow aging and significantly extend healthy lifespan. To identify the mechanism of these drug synergies, we applied transcriptomics and lipidomics analysis. We found that drug interactions involved the TGF-β pathway and recruited genes related with IGF signaling. daf-2, daf-7, and sbp-1 interact upstream of changes in lipid metabolism, resulting in increased monounsaturated fatty acid content and this is required for healthy lifespan extension. These data suggest that combinations of drugs targeting distinct subsets of the aging gene regulatory network can be leveraged to cause synergistic lifespan benefits., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Disruption of mitochondrial metabolism and loss of mitochondrial DNA (mtDNA) integrity are widely considered as evolutionarily conserved (public) mechanisms of aging (López-Otín et al., Cell, 153, 2013 and 1194). Human aging is associated with loss in skeletal muscle mass and function (Sarcopenia), contributing significantly to morbidity and mortality. Muscle aging is associated with loss of mtDNA integrity. In humans, clonally expanded mtDNA deletions colocalize with sites of fiber breakage and atrophy in skeletal muscle. mtDNA deletions may therefore play an important, possibly causal role in sarcopenia. The nematode Caenorhabditis elegans also exhibits age-dependent decline in mitochondrial function and a form of sarcopenia. However, it is unclear if mtDNA deletions play a role in C. elegans aging. Here, we report identification of 266 novel mtDNA deletions in aging nematodes. Analysis of the mtDNA mutation spectrum and quantification of mutation burden indicates that (a) mtDNA deletions in nematode are extremely rare, (b) there is no significant age-dependent increase in mtDNA deletions, and (c) there is little evidence for clonal expansion driving mtDNA deletion dynamics. Thus, mtDNA deletions are unlikely to drive the age-dependent functional decline commonly observed in C. elegans. Computational modeling of mtDNA dynamics in C. elegans indicates that the lifespan of short-lived animals such as C. elegans is likely too short to allow for significant clonal expansion of mtDNA deletions. Together, these findings suggest that clonal expansion of mtDNA deletions is likely a private mechanism of aging predominantly relevant in long-lived animals such as humans and rhesus monkey and possibly in rodents., (© 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

Arboviral diseases have risen significantly over the last 40 years, increasing the risk of co-infection with other endemic disease such as malaria. However, nothing is known about the impact arboviruses have on the host response toward heterologous pathogens during co-infection. Here, we investigate the effects of Chikungunya virus (CHIKV) co-infection on the susceptibility and severity of malaria infection. Using the Plasmodium berghei ANKA (PbA) experimental cerebral malaria (ECM) model, we show that concurrent co-infection induced the most prominent changes in ECM manifestation. Concurrent co-infection protected mice from ECM mortality without affecting parasite development in the blood. This protection was mediated by the alteration of parasite-specific CD8 + T-cell trafficking through an IFNγ-mediated mechanism. Co-infection with CHIKV induced higher splenic IFNγ levels that lead to high local levels of CXCL9 and CXCL10. This induced retention of CXCR3-expressing pathogenic CD8 + T cells in the spleen and prevented their migration to the brain. This then averts all downstream pathogenic events such as parasite sequestration in the brain and disruption of blood-brain barrier that prevents ECM-induced mortality in co-infected mice., (© 2017 Agency for Science, Technology and Research (A*STAR). Published under the terms of the CC BY 4.0 license.)

Zika virus (ZIKV) infections have been linked with neurological complications and congenital Zika syndrome. Given the high level of homology between ZIKV and the related flavivirus dengue virus (DENV), we investigated the level of cross-reactivity with ZIKV using a panel of DENV human mAbs. A majority of the mAbs showed binding to ZIKV virions, with several exhibiting neutralizing capacities against ZIKV in vitro. Three of the best ZIKV-neutralizing mAbs were found to recognize diverse epitopes on the envelope (E) glycoprotein: the highly conserved fusion-loop peptide, a conformation-specific epitope on the E monomer, and a quaternary epitope on the virion surface. The most potent ZIKV-neutralizing mAb (SIgN-3C) was assessed in 2 type I interferon receptor-deficient (IFNAR-/-) mouse models of ZIKV infection. Treatment of adult nonpregnant mice with SIgN-3C rescued mice from virus-induced weight loss and mortality. The SIgN-3C variant with Leu-to-Ala mutations in the Fc region (SIgN-3C-LALA) did not induce antibody-dependent enhancement (ADE) in vitro but provided similar levels of protection in vivo. In pregnant ZIKV-infected IFNAR-/- mice, treatment with SIgN-3C or SIgN-3C-LALA significantly reduced viral load in the fetal organs and placenta and abrogated virus-induced fetal growth retardation. Therefore, SIgN-3C-LALA holds promise as a ZIKV prophylactic and therapeutic agent.

Chikungunya virus (CHIKV) is a re-emerging vector-borne alphavirus, and there is no approved effective antiviral treatment currently available for CHIKV. We previously reported the discovery of thieno[3,2-b]pyrrole 1b that displayed good antiviral activity against CHIKV infection in vitro. However, it has a short half-life in the presence of human liver microsomes (HLMs) (T 1/2 = 2.91 min). Herein, we report further optimization studies in which potential metabolically labile sites on compound 1b were removed or modified, resulting in the identification of thieno[3,2-b]pyrrole 20 and pyrrolo[2,3-d]thiazole 23c possessing up to 17-fold increase in metabolic half-lives in HLMs and good in vivo pharmacokinetic properties. Compound 20 not only attenuated viral RNA production and displayed broad-spectrum antiviral activity against other alphaviruses and CHIKV isolates but also exhibited limited cytotoxic liability (CC 50 > 100 μM). These studies have identified two compounds that have the potential for further development as antiviral drugs against CHIKV infection.

Plasma leakage is a major pathogenic mechanism of severe dengue, but the etiology remains unclear. The association between endothelial glycocalyx integrity and vascular permeability in older adults with dengue has not been evaluated. A prospective cohort study of adults with undifferentiated fever screened for dengue by RT-PCR or NS1 antigen testing was performed. Patients were assessed daily while symptomatic and at convalescence. Serum hyaluronic acid (HA), heparan sulfate (HS) and selected cytokines (TNF-α, IL-6, IL-10) were measured on enrollment and convalescence. Patients were diagnosed as dengue fever (DF, n = 30), dengue hemorrhagic fever (DHF, n = 20) and non-dengue (ND) febrile illness (n = 11). Acute HA and HS levels were significantly higher in all dengue patients compared to ND (p = 0.0033 and p = 0.0441 respectively), but not different between DF and DHF (p = 0.3426 and p = 0.9180 respectively). Enrolment HA inversely correlated with serum albumin, protein and platelets in all dengue and DHF (p < 0.05). HA and HS in all dengue patients decreased significantly at convalescence. Serum IL-10 was significantly associated with HA in all dengue patients (p = 0.002). Serum HA and HS levels were increased in adult dengue and HA was associated with markers of disease severity. Endothelial glycocalyx damage may have a role in vascular leakage in dengue.

Hypometabolism may play an important role in the pathogenesis of ageing and ageing-related diseases. The nematode Caenorhabditis elegans offers the opportunity to study "living mitochondria" in a small (~1 mm) animal replete with a highly stereotypical, yet complex, anatomy and physiology. Basal oxygen consumption rate is often employed as a proxy for energy metabolism in this context. This parameter is traditionally measured using single-chamber Clark electrodes without the addition of metabolic modulators. Recently, multi-well oxygen electrodes, facilitating addition of metabolic modulators and hence study of respiratory control during different mitochondrial respiration states, have been developed. However, only limited official protocols exist for C. elegans, and key limitations of these techniques are therefore unclear. Following modification and testing of some of the existing protocols, we used these methods to explore mitochondrial bioenergetics in live nematodes of an electron transfer chain Complex II mutant strain, mev-1, and identified a previously undetected metabolic defect. We find that mev-1 mutants cannot respond adequately to increased energy demands, suggesting that oxidative phosphorylation is more severely impaired in these animals than has previously been appreciated.

Background: The unprecedented reemergence of Zika virus (ZIKV) has startled the world with reports of increased microcephaly in Brazil. ZIKV can infect human neural progenitors and impair brain growth. However, direct evidence of ZIKV infection in human fetal brain tissues remains elusive., Methods: Investigations were performed with brain cell preparations obtained from 9 donors. Virus infectivity was assessed by detection of virus antigen by flow cytometry together with various hematopoietic cell surface markers. Virus replication was determined by viral RNA quantification. Cytokine levels in supernatant obtained from virus-infected fetal brain cells were measured simultaneously in microbead-based immunoassays., Results: We also show that ZIKV infection was particularly evident in hematopoietic cells with microglia, the brain-resident macrophage population being one of the main targets. Infection induces high levels of proinflammatory immune mediators such as interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and monocyte chemotactic protein 1 (MCP-1)., Conclusions: Our results highlight an important role for microglia and neuroinflammation during congenital ZIKV pathogenesis., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

We have shown previously that prostratin, a non-tumor promoting phorbol ester, inhibits chikungunya virus (CHIKV)-induced cytopathic effects in vitro. Prostratin is a potent activator of protein kinases C (PKC), a family of related serine/threonine kinases that regulate many cellular processes such as proliferation and apoptosis. The objective of this study was to explore the mechanism of the anti-CHIKV activity of prostratin. Prostratin reduced the production of infectious virus particles and viral protein accumulation in a dose-dependent manner at a post-entry step during virus replication. The antiviral effect of the compound was cell-dependent, with potent antiviral activity observed in human skin fibroblasts cells, the primary target cells of CHIKV infection. The antiviral activity of prostratin was markedly reduced in the presence of PKC inhibitors, therefore confirming that the antiviral effect results from an activation of PKCs. Together these results showed that PKCs are potential host targets for the inhibition of CHIKV replication., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Chikungunya virus (CHIKV) is one of the many rheumatic arthropod-borne alphaviruses responsible for debilitating joint inflammation in humans. Despite the severity in many endemic regions, clinically approved intervention targeting the virus remains unavailable. CD4 + T cells have been shown to mediate CHIKV-induced joint inflammation in mice. We demonstrate here that transfer of splenic CD4 + T cells from virus-infected C57BL/6 mice into virus-infected T cell receptor-deficient (TCR -/- ) mice recapitulated severe joint pathology including inflammation, vascular leakages, subcutaneous edema, and skeletal muscle necrosis. Proteome-wide screening identified dominant CD4 + T cell epitopes in nsP1 and E2 viral antigens. Transfer of nsP1- or E2-specific primary CD4 + T cell lines into CHIKV-infected TCR -/- recipients led to severe joint inflammation and vascular leakage. This pathogenic role of virus-specific CD4 + T cells in CHIKV infections led to the assessment of clinically approved T cell-suppressive drugs for disease intervention. Although drugs targeting interleukin-2 pathway were ineffective, treatment with fingolimod, an agonist of sphingosine 1-phosphate receptor, successfully abrogated joint pathology in CHIKV-infected animals by blocking the migration of CD4 + T cells into the joints without any effect on viral replication. These results set the stage for further clinical evaluation of fingolimod in the treatment of CHIKV-induced joint pathologies., (Copyright © 2017, American Association for the Advancement of Science.)

Background:  Dengue virus infection typically causes mild dengue fever, but, in severe cases, life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) occur. The pathophysiological hallmark of DHF and DSS is plasma leakage that leads to enhanced vascular permeability, likely due to a cytokine storm., Methods:  Ninety patients with dengue during 2010-2012 in Singapore were prospectively recruited and stratified according to their disease phase, primary and secondary infection status, and disease severity, measured by plasma leakage. Clinical parameters were recorded throughout the disease progression. The levels of various immune mediators were quantified using comprehensive multiplex microbead-based immunoassays for 46 immune mediators., Results:  Associations between clinical parameters and immune mediators were analyzed using various statistical methods. Potential immune markers, including interleukin 1 receptor antagonist, interferon γ-inducible protein 10, hepatocyte growth factor, soluble p75 tumor necrosis factor α receptor, vascular cell adhesion molecule 1, and matrix metalloproteinase 2, were significantly associated with significant plasma leakage. Secondary dengue virus infections were also shown to influence disease outcome in terms of disease severity., Conclusions:  This study identified several key markers for exacerbated dengue pathogenesis, notably plasma leakage. This will allow a better understanding of the molecular mechanisms of DHF and DSS in patients with dengue., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

In recent years, various large-scale proteomic studies have demonstrated that mitochondrial proteins are highly acylated, most commonly by addition of acetyl and succinyl groups. These acyl modifications may be enzyme catalysed but can also be driven non-enzymatically. The latter mechanism is promoted in mitochondria due to the nature of the mitochondrial microenvironment, which is alkaline and contains high concentrations of acyl-CoA species. Protein acylation may modify enzyme activity, typically inhibiting it. We posited that organismal ageing might be accompanied by an accumulation of acylated proteins, especially in mitochondria, and that this might compromise mitochondrial function and contribute to ageing. In this study, we used R. norvegicus, C. elegans and D. melanogaster to compare the acylation status of mitochondrial proteins between young and old animals. We observed a specific age-dependent increase in protein succinylation in worms and flies but not in rat. Rats have two substrate-specific mitochondrial deacylases, SIRT3 and SIRT5 while both flies and worms lack these enzymes. We propose that accumulation of mitochondrial protein acylation contributes to age-dependent mitochondrial functional decline and that SIRT3 and SIRT5 enzymes may promote longevity through regulation of mitochondrial protein acylation during ageing., Competing Interests: The authors have declared that no competing interests exist.