The E3 ubiquitin ligase TRIM25 is a key factor in the innate immune response to RNA viruses. TRIM25 has been shown to play a role in the retinoic-acid-inducible gene-1 (RIG-I) pathway, which triggers ...expression of type 1 interferons upon viral infection. We and others have shown that TRIM25 is an RNA-binding protein; however, the role of TRIM25 RNA-binding in the innate immune response to RNA viruses is unclear. Here, we demonstrate that influenza A virus (IAV A/PR/8/34_NS1(R38A/K41A)) infection is inhibited by TRIM25. Surprisingly, previously identified RNA-binding deficient mutant TRIM25ΔRBD and E3 ubiquitin ligase mutant TRIM25ΔRING, which lack E3 ubiquitin ligase activity, still inhibited IAV replication. Furthermore, we show that in human-derived cultured cells, activation of the RIG-I/interferon type 1 pathway mediated by either an IAV-derived 5'-triphosphate RNA or by IAV itself does not require TRIM25 activity. Additionally, we present new evidence that instead of TRIM25 directly inhibiting IAV transcription it binds and destabilizes IAV mRNAs. Finally, we show that direct tethering of TRIM25 to RNA is sufficient to downregulate the targeted RNA. In summary, our results uncover a potential mechanism that TRIM25 uses to inhibit IAV infection and regulate RNA metabolism.
The accessory protein, PB1-F2, of influenza A virus (IAV) functions in a chicken host to prolong infectious virus shedding and thus the transmission window. Here we show that this delay in virus ...clearance by PB1-F2 in chickens is accompanied by reduced transcript levels of type 1 interferon (IFN)-induced genes and NFκB-activated pro-inflammation cytokines. In vitro, two avian influenza isolate-derived PB1-F2 proteins, H9N2 UDL01 and H5N1 5092, exhibited the same antagonism of the IFN and pro-inflammation induction pathways seen in vivo, but to different extents. The two PB1-F2 proteins had different cellular localization in chicken cells, with H5N1 5092 being predominantly mitochondrial-associated and H9N2 UDL being cytoplasmic but not mitochondrial-localized. We hypothesized that PB1-F2 localization might influence the functionality of the protein during infection and that the protein sequence could alter cellular localization. We demonstrated that the sequence of the C-terminus of PB1-F2 determined cytoplasmic localization in chicken cells and this was linked with protein instability. Mitochondrial localization of PB1-F2 resulted in reduced antagonism of an NFκB-dependent promoter. In parallel, mitochondrial localization of PB1-F2 increased the potency of chicken IFN 2 induction antagonism. We suggest that mitochondrial localization of PB1-F2 restricts interaction with cytoplasmic-located IKKβ, reducing NFκB-responsive promoter antagonism, but enhances antagonism of the IFN2 promoter through interaction with the mitochondrial adaptor MAVS. Our study highlights the differential mechanisms by which IAV PB1-F2 protein can dampen the avian host innate signalling response.
Although there is increasing evidence that aberrant expression of those enzymes which control protein arginine methylation contribute to carcinogenesis, their de-regulation by oncogenic viruses in ...primary cells has yet to be reported. We first show that the protein arginine methyltransferases, CARM1, PRMT1 and PRMT5 are strongly expressed in Hodgkin Reed-Sternberg (HRS) cells, and up-regulated in Hodgkin's lymphoma (HL) cell lines. Given that Epstein-Barr virus (EBV) can be detected in approximately 50% of primary HL, we next examined how EBV infection of germinal centre (GC) B cells, the presumptive precursors of HRS cells, modulated the expression of these proteins. EBV infection of GC B cells was followed by the up-regulation of CARM1, PRMT1 and PRMT5, and by the down-regulation of the arginine deiminase, PADI4. Latent membrane protein 1 (LMP1), the major EBV transforming gene was shown to induce PRMT1 in GC B cells and in a stably transfected B cell line. The recent development of compounds which inhibit PRMT-mediated reactions provides a compelling case for continuing to dissect the contribution of virus induced changes in these proteins to lymphomagenesis.
Long COVID (LC) is a global public health crisis affecting more than 70 million people. There is emerging evidence of different pathophysiological mechanisms driving the wide array of symptoms in LC. ...Understanding the relationships between mechanisms and symptoms helps in guiding clinical management and identifying potential treatment targets.
This was a mixed-methods systematic review with two stages: Stage one (Review 1) included only existing systematic reviews (meta-review) and Stage two (Review 2) was a review of all primary studies. The search strategy involved Medline, Embase, Emcare, and CINAHL databases to identify studies that described symptoms and pathophysiological mechanisms with statistical analysis and/or discussion of plausible causal relationships between mechanisms and symptoms. Only studies that included a control arm for comparison were included. Studies were assessed for quality using the National Heart, Lung, and Blood Institute quality assessment tools.
19 systematic reviews were included in Review 1 and 46 primary studies in Review 2. Overall, the quality of reporting across the studies included in this second review was moderate to poor. The pathophysiological mechanisms with strong evidence were immune system dysregulation, cerebral hypoperfusion, and impaired gas transfer in the lungs. Other mechanisms with moderate to weak evidence were endothelial damage and hypercoagulation, mast cell activation, and auto-immunity to vascular receptors.
LC is a complex condition affecting multiple organs with diverse clinical presentations (or traits) underpinned by multiple pathophysiological mechanisms. A 'treatable trait' approach may help identify certain groups and target specific interventions. Future research must include understanding the response to intervention based on these mechanism-based traits.
Hospital outbreaks of COVID19 result in considerable mortality and disruption to healthcare services and yet little is known about transmission within this setting. We characterise within hospital ...transmission by combining viral genomic and epidemiological data using Bayesian modelling amongst 2181 patients and healthcare workers from a large UK NHS Trust. Transmission events were compared between Wave 1 (1st March to 25th J'uly 2020) and Wave 2 (30th November 2020 to 24th January 2021). We show that staff-to-staff transmissions reduced from 31.6% to 12.9% of all infections. Patient-to-patient transmissions increased from 27.1% to 52.1%. 40%-50% of hospital-onset patient cases resulted in onward transmission compared to 4% of community-acquired cases. Control measures introduced during the pandemic likely reduced transmissions between healthcare workers but were insufficient to prevent increasing numbers of patient-to-patient transmissions. As hospital-acquired cases drive most onward transmission, earlier identification of nosocomial cases will be required to break hospital transmission chains.
The use of toxicokinetic (TK) data is becoming more prevalent in the evaluation of food ingredient safety as more TK information is being incorporated in safety data packages. Data demonstrating “1) ...the extent of absorption, 2) tissue distribution, 3) pathways and rates of metabolism, and 4) rate(s) of elimination” of food ingredients and their metabolites of intermediate and high toxicological potential may be useful for planning and designing toxicity studies, selecting doses for toxicity studies, addressing species differences, and understanding the potential modes of action to evaluate their safety. TK data reported in the literature or generated from mechanistic TK studies can be analyzed using mathematical methods, including compartment and noncompartment TK methods, whose predictions can enhance interpretation of observed effects. Because of recent advancements, several approaches have been developed to improve sensitivity of analyses of available TK data and reduce uncertainty for evaluating safety of food ingredients. An example of advanced TK methods is physiologically-based TK (PBTK) modeling that incorporates physiological/biochemical parameters into a TK framework to predict internal exposure. In this review, we discuss the utility of some TK methods and explore their relevance and potential value for food ingredient safety evaluation. We also describe the strengths and limitations of these TK methods and discuss current challenges and opportunities for expanding their application for evaluating safety of food ingredients. This review represents a state of science report, and not a guidance document, on the utility and relevance of TK methods for the safety evaluation of food ingredients.
Aims Valproate is a licensed medicine prescribed within mental health settings for bipolar disorder. It is a known teratogen, affecting approximately 20,000 people and costing the NHS £181 billion. ...This was a multidisciplinary project involving Surrey Heartlands Medicines Safety Team and Surrey and Borders Partnership NHS Foundation Trust, who developed a solution to reduce human suffering and cost by adhering to the Medicines and Healthcare Products Regulatory Agency (MHRA) valproate regulations through a clinical and digital redesign. The aim was to identify females in primary and secondary care across Surrey who take valproate for mental illness and to implement a pregnancy prevention programme for them by July 2022, using a digital clinical pathway supporting clinicians in the implementation process. Methods The method used was a combination of the Model for Improvement, the sequence for improvement from East London NHS Foundation Trust, UX design, and Agile project management. A valproate working group was formed with professionals from multiple disciplines to identify, understand and solve the problem. The solution was designed through co-production and project management methods that ensured a patient-centric solution. Results A digital registry of all females of childbearing potential who are prescribed valproate was created. A bespoke electronic GP referral form for valproate reviews was implemented. A one-stop valproate dashboard was developed to support documentation. A live digital visualisation feature was added within the secondary care electronic patient record to ensure compliance with MHRA guidelines. Easy-to-read materials for females with learning disabilities and sensitively worded appointment letters that inform patients of the risks and importance of attending annual reviews were created. In addition, collaboration with the National Valproate Patient Safety Officer allowed the implementation of Systematized Nomenclature of Medicine Clinical Terms (SNOMED) codes to simplify the exchange of clinical information between systems. Conclusion The project has the potential to reduce harm and improve the patient experience, serving as a template for other medications with strong regulatory controls. Collaboration between primary and secondary care, clinicians, pharmacists and digital colleagues, and co-design with people prescribed valproate were essential to the success of the project. Ongoing work is required to ensure valproate-related materials are available in an accessible format for every person prescribed valproate. Valproate has also been implicated in paternal adverse effects, and this project solution is future-proofed to identify men on valproate. Through this work, people will only be treated with valproate in a way that safeguards the health of unborn children.
Previous infection with SARS-CoV-2 affects the immune response to the first dose of the SARS-CoV-2 vaccine. We aimed to compare SARS-CoV-2-specific T-cell and antibody responses in health-care ...workers with and without previous SARS-CoV-2 infection following a single dose of the BNT162b2 (tozinameran; Pfizer–BioNTech) mRNA vaccine.
We sampled health-care workers enrolled in the PITCH study across four hospital sites in the UK (Oxford, Liverpool, Newcastle, and Sheffield). All health-care workers aged 18 years or older consenting to participate in this prospective cohort study were included, with no exclusion criteria applied. Blood samples were collected where possible before vaccination and 28 (±7) days following one or two doses (given 3–4 weeks apart) of the BNT162b2 vaccine. Previous infection was determined by a documented SARS-CoV-2-positive RT-PCR result or the presence of positive anti-SARS-CoV-2 nucleocapsid antibodies. We measured spike-specific IgG antibodies and quantified T-cell responses by interferon-γ enzyme-linked immunospot assay in all participants where samples were available at the time of analysis, comparing SARS-CoV-2-naive individuals to those with previous infection.
Between Dec 9, 2020, and Feb 9, 2021, 119 SARS-CoV-2-naive and 145 previously infected health-care workers received one dose, and 25 SARS-CoV-2-naive health-care workers received two doses, of the BNT162b2 vaccine. In previously infected health-care workers, the median time from previous infection to vaccination was 268 days (IQR 232–285). At 28 days (IQR 27–33) after a single dose, the spike-specific T-cell response measured in fresh peripheral blood mononuclear cells (PBMCs) was higher in previously infected (n=76) than in infection-naive (n=45) health-care workers (median 284 IQR 150–461 vs 55 IQR 24–132 spot-forming units SFUs per 106 PBMCs; p<0·0001). With cryopreserved PBMCs, the T-cell response in previously infected individuals (n=52) after one vaccine dose was equivalent to that of infection-naive individuals (n=19) after receiving two vaccine doses (median 152 IQR 119–275 vs 162 104–258 SFUs/106 PBMCs; p=1·00). Anti-spike IgG antibody responses following a single dose in 142 previously infected health-care workers (median 270 373 IQR 203 461–535 188 antibody units AU per mL) were higher than in 111 infection-naive health-care workers following one dose (35 001 17 099–55 341 AU/mL; p<0·0001) and higher than in 25 infection-naive individuals given two doses (180 904 108 221–242 467 AU/mL; p<0·0001).
A single dose of the BNT162b2 vaccine is likely to provide greater protection against SARS-CoV-2 infection in individuals with previous SARS-CoV-2 infection, than in SARS-CoV-2-naive individuals, including against variants of concern. Future studies should determine the additional benefit of a second dose on the magnitude and durability of immune responses in individuals vaccinated following infection, alongside evaluation of the impact of extending the interval between vaccine doses.
UK Department of Health and Social Care, and UK Coronavirus Immunology Consortium.
Given the large numbers of people infected and high rates of ongoing morbidity, research is clearly required to address the needs of adult survivors of COVID-19 living with ongoing symptoms (long ...COVID). To help direct resource and research efforts, we completed a research prioritisation process incorporating views from adults with ongoing symptoms of COVID-19, carers, clinicians and clinical researchers. The final top 10 research questions were agreed at an independently mediated workshop and included: identifying underlying mechanisms of long COVID, establishing diagnostic tools, understanding trajectory of recovery and evaluating the role of interventions both during the acute and persistent phases of the illness.
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