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An ISR-independent role of GCN2 prevents excessive ribosome biogenesis and mRNA translation.
No full textThe integrated stress response (ISR) is a corrective physiological programme to restore cellular homeostasis that is based on the attenuation of global protein synthesis and a resource-enhancing transcriptional programme. GCN2 is the oldest of four kinases that are activated by diverse cellular stresses to trigger the ISR and acts as the primary responder to amino acid shortage and ribosome collisions. Here, using a broad multi-omics approach, we uncover an ISR-independent role of GCN2. GCN2 inhibition or depletion in the absence of discernible stress causes excessive protein synthesis and ribosome biogenesis, perturbs the cellular translatome, and results in a dynamic and broad loss of metabolic homeostasis. Cancer cells that rely on GCN2 to keep protein synthesis in check under conditions of full nutrient availability depend on GCN2 for survival and unrestricted tumour growth. Our observations describe an ISR-independent role of GCN2 in regulating the cellular proteome and translatome and suggest new avenues for cancer therapies based on unleashing excessive mRNA translation
Use of metabolic imaging to monitor heterogeneity of tumour response following therapeutic mTORC1/2 pathway inhibition.
No full textThe PI3K-mTOR-AKT pathway regulates tumour proliferation, gene expression and metabolism, but pathway inhibition induces heterogeneous feedback reactivation, limiting anti-tumour responses. Measuring heterogeneity of pathway inhibition in tissues using protein biomarker phosphorylation or location is challenging. An integrated multi-modal imaging workflow was developed to assess the heterogeneity of AZD2014 (mTORC1/2 inhibitor) response in a PTEN-null renal cancer model. Spatial responses of metabolite biomarkers were analysed by mass spectrometry imaging (MSI). Control and treated tumours were classified according to metabolite-defined regions enriched in control versus AZD2014-treated tumours, respectively. Noticeably, AZD2014-treated tumours retained regions similar to regions dominant in untreated tumours. Imaging mass cytometry analysis of protein biomarkers in 'control-like' regions following AZD2014 treatment showed reduced phospho-S6, indicating suppression, but retained high expression of the glucose transporter GLUT1. Increasing PI3K-AKT inhibition by combining with AZD8186 (PI3Kβ inhibitor) further decreased the control-like metabolic signature, showing PI3K-dependent resistance. This demonstrates that MSI-based workflows yield novel insights into the pharmacodynamic effects of mTORC1/2 inhibition in tumours, which classical biomarkers do not resolve. Coupling these workflows with spatial-omics approaches can deliver greater insights into heterogeneity of treatment response
Subunit specialization in AAA+ proteins and substrate unfolding during transcription complex remodeling.
No full textBacterial RNA polymerase (RNAP) is a multisubunit enzyme that copies DNA into RNA in a process known as transcription. Bacteria use σ factors to recruit RNAP to promoter regions of genes that need to be transcribed, with 60% bacteria containing at least one specialized σ factor, σ54. σ54 recruits RNAP to promoters of genes associated with stress responses and forms a stable closed complex that does not spontaneously isomerize to the open state where promoter DNA is melted out and competent for transcription. The σ54-mediated open complex formation requires specific AAA+ proteins (ATPases Associated with diverse cellular Activities) known as bacterial enhancer-binding proteins (bEBPs). We have now obtained structures of new intermediate states of bEBP-bound complexes during transcription initiation, which elucidate the mechanism of DNA melting driven by ATPase activity of bEBPs and suggest a mechanistic model that couples the Adenosine triphosphate (ATP) hydrolysis cycle within the bEBP hexamer with σ54 unfolding. Our data reveal that bEBP forms a nonplanar hexamer with the hydrolysis-ready subunit located at the furthest/highest point of the spiral hexamer relative to the RNAP. ATP hydrolysis induces conformational changes in bEBP that drives a vectoral transiting of the regulatory N terminus of σ54 into the bEBP hexamer central pore causing the partial unfolding of σ54, while forming specific bEBP contacts with promoter DNA. Furthermore, our data suggest a mechanism of the bEBP AAA+ protein that is distinct from the hand-over-hand mechanism proposed for many other AAA+ proteins, highlighting the versatile mechanisms utilized by the large protein family
Autophagy is an upstream mediator of chromatin dynamics in normal and autoimmune germinal centre B cells.
No full textGerminal centre (GC) B cells are pivotal in establishing a robust humoral immune response and long-term serological immunity while maintaining antibody self-tolerance. GC B cells rely on autophagy for antigen presentation and homeostatic maintenance. However, these functions, primarily associated with the light zone, cannot explain the spatiotemporal autophagy upregulation in the dark zone of GCs. Here, we define a functional mechanism controlling chromatin accessibility in GC B cells during their dark zone transition. This mechanism links autophagy and nuclear Lamin B1 dynamics with their downstream effects, including somatic hypermutation and antibody affinity maturation. Moreover, the autophagy-Lamin B1 axis is highly active in the aberrant ectopic germinal centres in the salivary glands of Sjogren's disease, defining its role in autoimmunity
Accomplishments and challenges in developing improved influenza vaccines: An evaluation of three years of progress toward the milestones of the influenza vaccines research and development roadmap
No full textInfluenza vaccines that provide more effective immunity to seasonal influenza as well as protection against a broad range of emerging influenza viruses with pandemic potential are needed to reduce the public-health burden of influenza and enhance pandemic preparedness. The Influenza Vaccines Research and Development (R&D) Roadmap (IVR) was published in 2021 to serve as a strategic planning tool to advance influenza vaccine R&D. Following IVR publication, a 3-year monitoring, evaluation, and adjustment (ME&A) program was implemented to assess progress in meeting the milestones outlined in the IVR. As of mid-May 2025, 16 (17%) of the 93 milestones had been accomplished or partially accomplished, with the majority (67; 72%) in various stages of progress. Of the 35 milestones designated high-priority, five (14%) had been accomplished or partially accomplished, 29 (83%) are in progress, and no progress was identified for one (3%). Key accomplishments include: establishing longitudinal cohort studies to characterize immune responses to influenza virus infection and vaccination by age over time and by vaccine product; creating a comprehensive landscape of innovative influenza vaccine technologies in preclinical and clinical development; advancing next-generation and broadly protective influenza vaccine candidates into clinical trials; identifying relevant lessons learned from accelerated SARS-CoV-2 vaccine development during the COVID-19 pandemic; and initiating development of a full value of improved influenza vaccine assessment (FVIVA) to inform investment and guide the eventual uptake of improved vaccines globally. Persistent challenges include clarifying immune mechanisms for generating durable and broadly protective immunity, enhancing understanding of immune imprinting and the role of mucosal immunity in preventing infection and transmission, identifying correlates of protection, and exploring regulatory options for broadly protective influenza vaccine licensure. The IVR ME&A program provides a basis for ongoing critical review of progress in influenza vaccine R&D to inform decision-making on research priorities and funding
NeuralProg_DiffCom16Oct
No full textDifferentiations from 16 October. Constant SAG at different concentrations. </p
<b>EVOLVE-HBV: </b><b>Report of a Road Show to engage local communities </b><b>in a Hepatitis B Programme, in KwaZulu Natal, South Africa</b>
No full textThis document reports on a community Roadshow that was hosted in the KwaZulu Natal district of South Africa in November 2024. The Roadshow set out to engage members of the local community with a study of hepatitis B virus (HBV), EVOLVE-HBV (Evaluation of Vukuzazi LiVEr disease - Hepatitis B) . EVOLVE-HBV project was introduced to conduct research on Hepatitis B infection in South Africa. The study is linked to the Vukuzazi programme, a collaboration between the Africa Health Research Institute (AHRI) and the uMkhanyakude community in KwaZulu-Natal, South Africa. Vukuzazi used mobile clinics to collect health-related data in between 2018-2020. The report is for members of the research community, participants in the event, funders and sponsors, in order to provide a record of activities, and to inform future planning. </p
Hepatitis B core-related antigen rapid diagnostic test for point-of-care identification of women at high risk of hepatitis B vertical transmission: a multicountry diagnostic accuracy study.
No full textBACKGROUND: Timely administration of the hepatitis B virus (HBV) birth dose vaccine, along with identifying high-risk pregnant individuals for antiviral prophylaxis, is essential for the global elimination of vertical transmission of HBV. However, in resource-limited settings, access to HBV DNA testing is scarce, and accurate rapid tests for HBeAg are lacking. We aimed to assess the diagnostic performance of a newly developed hepatitis B core-related antigen (HBcrAg) rapid diagnostic test (RDT) to identify women who are HBsAg-positive and eligible for antiviral prophylaxis. METHODS: In this multicountry diagnostic accuracy study, we retrospectively validated the HBcrAg-RDT using stored plasma from pregnant women who were HBsAg-positive in cohort studies from Cambodia and Cameroon and prospectively using finger-prick capillary blood from postpartum mothers at rural health centres in Burkina Faso. We estimated the sensitivity and specificity of the HBcrAg-RDT for diagnosing high HBV DNA concentrations (≥200 000 IU/mL) using real-time PCR (rtPCR) as the reference. We compared the diagnostic performance of the HBcrAg-RDT with that of conventional HBeAg assays based on the area under the receiver operating characteristic curve (AUROC). FINDINGS: In total, plasma samples were available for 1964 participants: 1194 stored plasma samples available for analysis from the Cambodian cohort, 501 stored samples from the Cameroonian cohort, and 269 prospectively collected samples from women in the Burkina Faso cohort. In the pooled population, the mean age was 28·1 years (SD 6·0), and 382 (20·0%) were HBeAg positive. The HBcrAg-RDT showed an overall sensitivity of 93·1% (95% CI 90·5-95·2) and specificity of 94·3% (93·0-95·4). Sensitivity and specificity were 93·4% (90·7-95·5) and 94·4% (92·9-95·6) in the retrospective laboratory-based analyses of samples from Cambodia and Cameroon, and 89·7% (75·8-97·1) and 93·9% (90·0-96·6) in the prospective real-world analysis of samples of HBsAg-positive women from Burkina Faso. The AUROC for HBcrAg-RDT (0·937 [95% CI 0·924-0·950]) in distinguishing high versus low HBV DNA concentrations at the 200 000 IU/mL threshold in the pooled data set was significantly higher than that of HBeAg rapid tests (0·822 [0·798-0·845]; p<0·0001) and similar to laboratory-based HBeAg immunoassays (ELISA and chemiluminescence assay; 0·926 [0·897-0·955]; p=0·72). In Burkina Faso, the median turnaround time for HBV DNA testing was 46 days (IQR 31-72), whereas HBcrAg-RDT provided same-day results for all participants. INTERPRETATION: HBcrAg-RDT might offer a practical solution for integrating the prevention of vertical transmission of HBV into decentralised antenatal care in resource-limited settings, enabling timely identification and management of pregnant individuals who are at high risk of transmission. FUNDING: Agence Nationale de Recherches sur le Sida et les Hépatites Virales, Total Foundation, Gilead Sciences, and Japan Society for the Promotion of Science. TRANSLATION: For the French translation of the abstract see Supplementary Materials section
Immunomodulatory effects of atorvastatin on peripheral blood mononuclear cells infected with Mycobacterium tuberculosis.
No full textBACKGROUND: Tuberculosis (TB) remains a major global health threat, contributing substantially to high morbidity and mortality rates. This underscores the urgent need for more effective interventions. Recent studies highlight the potential of host-directed therapy approaches to enhance immune defences against TB. Atorvastatin, recognized for both its lipid-lowering properties and its immunomodulatory effects, has emerged as a compelling candidate for host-directed therapy against TB. Here, we investigated the ex vivo efficacy of atorvastatin in inducing immunomodulatory activities (phagosome maturation, autophagy, and apoptosis) and enhancing the mycobacterial killing capacity in Mycobacterium tuberculosis (Mtb)-infected peripheral blood mononuclear cells (PBMCs). METHOD: Blood samples from healthy donors were collected for PBMC isolation. PBMCs were then treated overnight with or without atorvastatin, followed by infection with Mtb strains (H37Rv, HN878, and CDC1551) to evaluate intracellular mycobacterial growth by colony-forming units enumeration. Furthermore, co-localization of late endosomal marker (Rab-7), lysosomal markers (Cathepsin-D and LAMP-3), and autophagy marker (LC3B) with GFP-Mtb was investigated in infected PBMCs using laser scanning confocal microscopy. Moreover, multiple apoptotic assays were performed, including the TUNEL assay for DNA fragmentation, quantification of caspase-3 activity, and the expression levels of the pro-apoptotic gene (Bax) and anti-apoptotic gene (Bcl2). RESULTS: Treatment with atorvastatin significantly reduced intracellular mycobacterial replication compared to untreated controls in Mtb-infected PBMCs. Moreover, atorvastatin enhanced co-localization between Mtb and late endosomal marker (Rab-7), lysosomal markers (Cathepsin-D and LAMP-3), and autophagy marker (LC3B) in Mtb-infected PBMCs. Furthermore, atorvastatin robustly promoted apoptosis in Mtb-infected PBMCs, as demonstrated by TUNEL assay and caspase-3 activation. CONCLUSION: Our findings highlight atorvastatin's potential as a crucial modulator of the immune response in Mtb-infected PBMCs, supporting its role in host-directed therapy