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Asparagine availability controls germinal center B cell homeostasis.
The rapid proliferation of germinal center (GC) B cells requires metabolic reprogramming to meet energy demands, yet these metabolic processes are poorly understood. By integrating metabolomic and transcriptomic profiling of GC B cells, we identified that asparagine (Asn) metabolism was highly up-regulated and essential for B cell function. Asparagine synthetase (ASNS) was up-regulated after B cell activation through the integrated stress response sensor GCN2. Conditional deletion of Asns in B cells impaired survival and proliferation in low Asn conditions. Removal of environmental Asn by asparaginase or dietary restriction compromised the GC reaction, impairing affinity maturation and the humoral response to influenza infection. Furthermore, metabolic adaptation to the absence of Asn required ASNS, and oxidative phosphorylation, mitochondrial homeostasis, and synthesis of nucleotides were particularly sensitive to Asn deprivation. These findings demonstrate that Asn metabolism acts as a key regulator of B cell function and GC homeostasis.
Dysregulation of MMP2-dependent TGF-ß2 activation impairs fibrous cap formation in type 2 diabetes-associated atherosclerosis.
Type 2 diabetes is associated with cardiovascular disease, possibly due to impaired vascular fibrous repair. Yet, the mechanisms are elusive. Here, we investigate alterations in the fibrous repair processes in type 2 diabetes atherosclerotic plaque extracellular matrix by combining multi-omics from the human Carotid Plaque Imaging Project cohort and functional studies. Plaques from type 2 diabetes patients have less collagen. Interestingly, lower levels of transforming growth factor-ß distinguish type 2 diabetes plaques and, in these patients, lower levels of fibrous repair markers are associated with cardiovascular events. Transforming growth factor-ß2 originates mostly from contractile vascular smooth muscle cells that interact with synthetic vascular smooth muscle cells in the cap, leading to collagen formation and vascular smooth muscle cell differentiation. This is regulated by free transforming growth factor-ß2 which is affected by hyperglycemia. Our findings underscore the importance of transforming growth factor-ß2-driven fibrous repair in type 2 diabetes as an area for future therapeutic strategies.
Immunogenicity of MVA-BN vaccine deployed as mpox prophylaxis: a prospective cohort study and analysis of transcriptomic predictors of response
Background: Since 2022, mpox has emerged as a global health threat, with two clades (I and II) causing outbreaks of international public health concern. The third generation smallpox vaccine modified vaccinia Ankara, manufactured by Bavarian Nordic (MVA-BN), has emerged as a key component of mpox prevention. To date, the immunogenicity of this vaccine, including determinants of response has been incompletely described, especially when MVA-BN has been administered intradermally at 1/5th the registered dose (‘fractionated dosing’), as recommended as a dose-sparing strategy. The aim of this study was to explore the immunogenicity of MVA-BN, and baseline determinants of vaccine response in an observational public-health response setting. Methods: We conducted a prospective cohort study and immunological analysis of responses to MVA-BN in patients attending a sexual health vaccination clinic in Oxford, UK. Blood samples were taken at baseline, day 14, and day 28 after first vaccine, and 28 and 90 days following a second vaccine. A sub-cohort had additional blood samples collected day 1 following their first vaccine (optional timepoint). We assessed IgG responses to mpox/vaccinia antigens using Luminex assay (‘MpoxPlex’) via generalised linear mixed modelling, and T-cell responses using interferon- enzyme linked immunospot and activation induced marker assay. Associations between blood transcriptomic signatures (baseline, day 1) and immunogenicity were assessed using differential expression analysis and gene set enrichment methods. Findings: We recruited 34 participants of whom 33 received fractionated dosing. Of those without prior smallpox vaccination (n=30), 50% seroconverted by day 28, and while this increased to 89% by day 90 post second vaccination, individuals seronegative on day 28 demonstrated persistently lower responses compared to day 28 seropositive individuals. Serological response on day 28 positively associated with type I and II interferon signatures day one post-vaccination (n=18 samples) but negatively associated with these signatures at baseline. Interpretation: Baseline inflammatory states may inhibit MVA-BN serological immunogenicity by inhibiting the upregulation of MVA-induced innate immune signalling. If confirmed mechanistically these insights may inform improved vaccination strategies against mpox in diverse geographic and demographic settings. Given the likelihood of vaccine supply limitations in the current context and in future outbreak settings, the utility of dose-sparing vaccine strategies as a general approach to maximising population benefit warrants further study
Development of methodology to support molecular endotype discovery from synovial fluid of individuals with knee osteoarthritis: The STEpUP OA consortium.
OBJECTIVES: To develop a protocol for largescale analysis of synovial fluid proteins, for the identification of biological networks associated with subtypes of osteoarthritis. METHODS: Synovial Fluid To detect molecular Endotypes by Unbiased Proteomics in Osteoarthritis (STEpUP OA) is an international consortium utilising clinical data (capturing pain, radiographic severity and demographic features) and knee synovial fluid from 17 participating cohorts. 1746 samples from 1650 individuals comprising OA, joint injury, healthy and inflammatory arthritis controls, divided into discovery (n = 1045) and replication (n = 701) datasets, were analysed by SomaScan Discovery Plex V4.1 (>7000 SOMAmers/proteins). An optimised approach to standardisation was developed. Technical confounders and batch-effects were identified and adjusted for. Poorly performing SOMAmers and samples were excluded. Variance in the data was determined by principal component (PC) analysis. RESULTS: A synovial fluid standardised protocol was optimised that had good reliability (<20% co-efficient of variation for >80% of SOMAmers in pooled samples) and overall good correlation with immunoassay. 1720 samples and >6290 SOMAmers met inclusion criteria. 48% of data variance (PC1) was strongly correlated with individual SOMAmer signal intensities, particularly with low abundance proteins (median correlation coefficient 0.70), and was enriched for nuclear and non-secreted proteins. We concluded that this component was predominantly intracellular proteins, and could be adjusted for using an 'intracellular protein score' (IPS). PC2 (7% variance) was attributable to processing batch and was batch-corrected by ComBat. Lesser effects were attributed to other technical confounders. Data visualisation revealed clustering of injury and OA cases in overlapping but distinguishable areas of high-dimensional proteomic space. CONCLUSIONS: We have developed a robust method for analysing synovial fluid protein, creating a molecular and clinical dataset of unprecedented scale to explore potential patient subtypes and the molecular pathogenesis of OA. Such methodology underpins the development of new approaches to tackle this disease which remains a huge societal challenge.
The Use of Fluorescent Markers to Detect and Delineate Head and Neck Cancer: A Scoping Review
ABSTRACTObjectivesThe aim of surgery for head and neck squamous cell carcinoma (HNSCC) is to achieve clear resection margins, whilst preserving function and cosmesis. Fluorescent markers have demonstrated potential in the intraoperative visualisation and delineation of tumours, such as glioma, with consequent improvements in resection. The purpose of this scoping review was to identify and compare the fluorescent markers that have been used to detect and delineate HNSCC to date.MethodsA literature search was performed using the Ovid MEDLINE, Ovid Embase, Cochrane CENTRAL, ClinicalTrials.gov and ICTRP databases. Primary human studies published through September 2023 demonstrating the use of fluorescent markers to visualise HNSCC were selected and reviewed independently by two authors.ResultsThe search strategy identified 5776 records. Two hundred and forty‐four full texts were reviewed, and sixty‐five eligible reports were included. The most used fluorescent markers in the included studies were indocyanine green (ICG) (n = 14), toluidine blue (n = 11), antibodies labelled with IRDye800CW (n = 10) and 5‐aminolevulinic acid (5‐ALA) (n = 8). Toluidine blue and ICG both have limited specificity, although novel targeted options derived from ICG may be more effective. 5‐ALA has been demonstrated as a topical marker and, recently, via enteral administration but it is associated with photosensitivity reactions. The fluorescently labelled antibodies cetuximab‐IRDye800CW and panitumumab‐IRDye800CW are promising options being investigated by ongoing trials.ConclusionMultiple safe fluorescent markers have emerged which may aid the surgical resection of HNSCC. Further research in larger cohorts is required to identify which marker should be considered gold standard.
Upadacitinib for Induction of Remission in Pediatric Ulcerative Colitis: An International Multi‑center Study.
BACKGROUND AND AIMS: Data on upadacitinib therapy in children with ulcerative colitis (UC) or unclassified inflammatory bowel disease (IBD-U) are scarce. We aimed to evaluate the effectiveness and safety of upadacitinib as an induction therapy in pediatric UC or IBD-U. METHODS: In this multicenter retrospective study, children treated with upadacitinib for induction of remission of active UC or IBD-U from 30 centers worldwide were enrolled. Demographic, clinical and laboratory data as well as adverse events (AEs) were recorded at week 8 post induction. RESULTS: One hundred children were included (90 UC and 10 IBD-U, median age 15.6 [interquartile range 13.3-17.1] years). Ninety-eight were previously treated with biologic therapies, and 76 were treated with ≥2 biologics. At the end of the 8-week induction period, clinical response, clinical remission, and corticosteroid-free clinical remission (CFR) were observed in 84%, 62%, and 56% of the children, respectively. Normal C-reactive protein and fecal calprotectin (FC) <150 mcg/g were achieved in 75% and 50%, respectively. Combined CFR and FC remission was observed in 18/46 (39%) children with available data at 8 weeks. AEs were recorded in 37 children, including one serious AE of an appendiceal neuroendocrine tumor. The most frequent AEs were hyperlipidemia (n=13), acne (n=12), and infections (n=10, five of whom with herpes viruses). CONCLUSION: Upadacitinib is an effective induction therapy for refractory pediatric UC and IBD-U. Efficacy should be weighed against the potential risks of AEs.
A multi-omic atlas of human embryonic skeletal development.
Human embryonic bone and joint formation is determined by coordinated differentiation of progenitors in the nascent skeleton. The cell states, epigenetic processes and key regulatory factors that underlie lineage commitment of these cells remain elusive. Here we applied paired transcriptional and epigenetic profiling of approximately 336,000 nucleus droplets and spatial transcriptomics to establish a multi-omic atlas of human embryonic joint and cranium development between 5 and 11 weeks after conception. Using combined modelling of transcriptional and epigenetic data, we characterized regionally distinct limb and cranial osteoprogenitor trajectories across the embryonic skeleton and further described regulatory networks that govern intramembranous and endochondral ossification. Spatial localization of cell clusters in our in situ sequencing data using a new tool, ISS-Patcher, revealed mechanisms of progenitor zonation during bone and joint formation. Through trajectory analysis, we predicted potential non-canonical cellular origins for human chondrocytes from Schwann cells. We also introduce SNP2Cell, a tool to link cell-type-specific regulatory networks to polygenic traits such as osteoarthritis. Using osteolineage trajectories characterized here, we simulated in silico perturbations of genes that cause monogenic craniosynostosis and implicate potential cell states and disease mechanisms. This work forms a detailed and dynamic regulatory atlas of bone and cartilage maturation and advances our fundamental understanding of cell-fate determination in human skeletal development.
A human embryonic limb cell atlas resolved in space and time.
Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months1. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common2. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.
A 3D atlas of the human developing pancreas to explore progenitor proliferation and differentiation
Abstract Aims/hypothesis Rodent pancreas development has been described in great detail. On the other hand, there are still gaps in our understanding of the developmental trajectories of pancreatic cells during human ontogenesis. Here, our aim was to map the spatial and chronological dynamics of human pancreatic cell differentiation and proliferation by using 3D imaging of cleared human embryonic and fetal pancreases. Methods We combined tissue clearing with light-sheet fluorescence imaging in human embryonic and fetal pancreases during the first trimester of pregnancy. In addition, we validated an explant culture system enabling in vitro proliferation of pancreatic progenitors to determine the mitogenic effect of candidate molecules. Results We detected the first insulin-positive cells as early as five post-conceptional weeks, two weeks earlier than previously observed. We observed few insulin-positive clusters at five post-conceptional weeks (mean ± SD 9.25±5.65) with a sharp increase to 11 post-conceptional weeks (4307±152.34). We identified a central niche as the location of onset of the earliest insulin cell production and detected extra-pancreatic loci within the adjacent developing gut. Conversely, proliferating pancreatic progenitors were located in the periphery of the epithelium, suggesting the existence of two separated pancreatic niches for differentiation and proliferation. Additionally, we observed that the proliferation ratio of progenitors ranged between 20% and 30%, while for insulin-positive cells it was 1%. We next unveiled a mitogenic effect of the platelet-derived growth factor AA isoform (PDGFAA) in progenitors acting through the pancreatic mesenchyme by increasing threefold the number of proliferating progenitors. Conclusions/interpretation This work presents a first 3D atlas of the human developing pancreas, charting both endocrine and proliferating cells across early development. Graphical Abstract
Phox2a Defines a Developmental Origin of the Anterolateral System in Mice and Humans.
Anterolateral system neurons relay pain, itch, and temperature information from the spinal cord to pain-related brain regions, but the differentiation of these neurons and their specific contribution to pain perception remain poorly defined. Here, we show that most mouse spinal neurons that embryonically express the autonomic-system-associated Paired-like homeobox 2A (Phox2a) transcription factor innervate nociceptive brain targets, including the parabrachial nucleus and the thalamus. We define the Phox2a anterolateral system neuron birth order, migration, and differentiation and uncover an essential role for Phox2a in the development of relay of nociceptive signals from the spinal cord to the brain. Finally, we also demonstrate that the molecular identity of Phox2a neurons is conserved in the human fetal spinal cord, arguing that the developmental expression of Phox2a is a prominent feature of anterolateral system neurons.
A tridimensional atlas of the developing human head.
The evolution and development of the head have long captivated researchers due to the crucial role of the head as the gateway for sensory stimuli and the intricate structural complexity of the head. Although significant progress has been made in understanding head development in various vertebrate species, our knowledge of early human head ontogeny remains limited. Here, we used advanced whole-mount immunostaining and 3D imaging techniques to generate a comprehensive 3D cellular atlas of human head embryogenesis. We present detailed developmental series of diverse head tissues and cell types, including muscles, vasculature, cartilage, peripheral nerves, and exocrine glands. These datasets, accessible through a dedicated web interface, provide insights into human embryogenesis. We offer perspectives on the branching morphogenesis of human exocrine glands and unknown features of the development of neurovascular and skeletomuscular structures. These insights into human embryology have important implications for understanding craniofacial defects and neurological disorders and advancing diagnostic and therapeutic strategies.
Association of intra-articular injection and knee arthroscopy prior to primary knee replacement with the timing and outcomes of surgery: Retrospective cohort study using data from the Clinical Practice Research Datalink GOLD database.
BACKGROUND: Patients with symptomatic knee osteoarthritis may undergo non-surgical interventions such as intra-articular steroid injections and knee arthroscopy. This study aimed to investigate their association with the timing and outcomes of subsequent primary knee replacement. METHODS AND FINDINGS: Observational retrospective analysis of linked Clinical Practice Research Datalink, Hospital Episode Statistics, Patient Reported Outcome Measures (CPRD GOLD-HES-PROMS) data of 38,494 patients undergoing primary knee replacements in England. Prior use of intra-articular steroid injections and knee arthroscopy were identified. Hazard ratios (HRs) with 95% CIs were estimated for primary outcomes of revision and reoperation using Cox regression. Secondary outcomes included time from first diagnosis of ipsilateral knee osteoarthritis to knee replacement, 6-month post-operative Oxford Knee Scores (OKS), mortality (90-days and 3-months), and post-operative surgical site infection (SSI) (3-months) using linear and logistic regression. Prior steroid injections were associated with an increased risk of revision (HR = 1.25 95%CI (1.06 to 1.49)), re-operation (HR = 1.18 95%CI (1.05 to 1.32)), and SSI (HR = 3.10 95%CI (1.14 to 8.46). Timing from diagnosis of knee osteoarthritis to knee replacement was 6 months longer in patients receiving steroid injections. Knee arthroscopy was associated with an increased risk of revision (HR = 3.14 95%CI (2.64 to 3.73)), re-operation (HR = 3.25 95%CI (2.89 to 3.66)), lower post-operative OKS -1.63 95%CI (-2.31 to -0.95). Both interventions were associated with a lower risk of mortality. CONCLUSIONS: Steroid injection and knee arthroscopy prior to primary knee replacement are each associated with worse outcomes. The observed association of lower mortality risk is suggestive of confounding by indication. The observed associations in this study could be used to inform shared decision making with patients on the treatment pathway for knee osteoarthritis.
Medium-term results of arthroscopic hip surgery compared with physiotherapy and activity modification for the treatment of femoroacetabular impingement syndrome: a multi-centre randomised controlled trial.
OBJECTIVE: To report a 3-year follow-up from the FemoroAcetabular Impingement Trial, comparing arthroscopic surgery with physiotherapy in the management of femoroacetabular impingement (FAI) syndrome for the dual primary outcomes of radiographic hip osteoarthritis (OA) and patient-reported outcome measures of activities of daily living. METHODS: Two-group parallel, assessor-blinded, pragmatic randomised controlled trial across seven sites. 222 participants aged 18-60 years with FAI syndrome confirmed clinically and radiologically were randomised (1:1) to receive arthroscopic hip surgery (n=112) or physiotherapy (n=110). Dual primary outcome measure was minimum joint space width (mJSW) on anteroposterior radiograph at 38 months post-randomisation and Hip Outcome Score ADL (HOS ADL) (higher score indicates superior outcomes). Secondary outcome measures were Scoring Hip Osteoarthritis with MRI (SHOMRI) (lower score indicates less pathology). RESULTS: mJSW, HOS ADL and MRI data were available for 45%, 77% and 62% of participants at 38 months, respectively. No significant difference in mJSW was seen between groups at 38 months. HOS ADL was higher in the arthroscopy group (mean (SD) 84.2 (17.4)) compared with the physiotherapy group (74.2 (21.9)), difference 8.9 (95% CI 7.0, 10.8)). SHOMRI score total at 38 months was lower in the arthroscopy group (mean (SD) 9.22 (11.43)) compared with the physiotherapy group (22.76 (15.26)), differences (95% CIs) -15.94 (-18.69, -13.19). CONCLUSIONS: No difference was seen between groups on radiographic measures of OA progression. Patients with FAI syndrome treated surgically may experience superior pain and function outcomes, and less MRI-measured cartilage damage compared with physiotherapy. TRIAL REGISTRATION NUMBER: NCT01893034.
Mucosal Healing with Vedolizumab in Patients with Chronic Pouchitis: EARNEST, a Randomized, Double-Blind, Placebo-Controlled Trial.
BACKGROUND & AIMS: Vedolizumab is indicated for the treatment of chronic pouchitis in the European Union. We assessed whether vedolizumab induced mucosal healing (MH) and if MH was associated with clinical improvements. METHODS: EARNEST, a randomized, double-blind, placebo-controlled study, evaluated vedolizumab efficacy and safety in adults with chronic pouchitis. Centrally read endoscopic and histologic evaluation was performed at baseline, Week (W)14, and W34. Ulcer count, adapted Simple Endoscopic Score for Crohn's Disease in the pouch, and Pouchitis Disease Activity Index histologic component were evaluated. Pouchitis Disease Activity Index and Inflammatory Bowel Disease Questionnaire remission at W14 and W34 were compared by MH status at W14. RESULTS: Following treatment, mean (standard deviation) number of ulcers in vedolizumab-treated patients reduced from 15.1 (16.4) to 5.0 (4.9) at W14 and 2.7 (3.2) at W34 versus placebo-treated patients with corresponding values of 11.8 (11.3), 13.4 (18.4), and 9.7 (13.8) (vedolizumab vs placebo difference [95% confidence interval]: W14: -8.4 [-14.3 to -2.6]; W34: -7.0 [-12.0 to -2.0]). More patients receiving vedolizumab versus placebo achieved reduction in ulcerated pouch surface area (W14: 52.4% vs 20.0%; difference, 32.4 percentage points [p.p] [9.7, 51.4]; W34: 52.1% vs 12.9%; difference, 40.2p.p [15.6, 60.3]), absence of ulceration (W14: 23.8% vs 7.5%; difference, 16.3p.p [1.1, 31.6]; W34: 34.4% vs 15.6%; difference, 18.8p.p [-2.0, 39.5]), Simple Endoscopic Score for Crohn's Disease remission (W14: 23.8% vs 7.5%; difference, 16.3p.p [1.1, 31.6]; W34: 34.4% vs 15.6%; difference, 18.8p.p [-2.0, 39.5]), and MH (W14: 16.7% vs 2.5%; difference, 14.2p.p [1.9, 26.4]). Patients with MH at W14 had higher rates of Pouchitis Disease Activity Index and Inflammatory Bowel Disease Questionnaire remission at W14 and W34 than those without. CONCLUSIONS: Vedolizumab induced endoscopic improvements in patients with chronic pouchitis, which was associated with improved outcomes at W34, particularly in patients achieving MH at W14. (ClinicalTrials.gov number, NCT02790138.).
Enhancing broadly neutralising antibody suppression of HIV by immune modulation and vaccination.
Although HIV infection can be managed with antiretroviral drugs, there is no cure and therapy has to be taken for life. Recent successes in animal models with HIV-specific broadly neutralising antibodies (bNAbs) have led to long-term virological remission and even possible cures in some cases. This has resulted in substantial investment in human studies to explore bNAbs as a curative intervention for HIV infection. Emerging data are encouraging, but suggest that combinations of bNAbs with other immunomodulatory agents may be needed to induce and sustain long-term viral control. As a result, a number of clinical trials are currently underway exploring these combinations. If successful, the impact for the millions of people living with HIV could be substantial. Here, we review the background to the use of bNAbs in the search for an HIV cure and how different adjunctive agents might be used together to enhance their efficacy.