The rockefeller university

Ageing is associated with a decline in the number and fitness of adult stem cells1,2. Ageing-associated loss of stemness is posited to suppress tumorigenesis3,4, but this hypothesis has not been tested in vivo. Here we use physiologically aged autochthonous genetically engineered5,6 mouse models and primary cells5,6 to demonstrate that ageing suppresses lung cancer initiation and progression by degrading the stemness of the alveolar cell of origin. This phenotype is underpinned by the ageing-associated induction of the transcription factor NUPR1 and its downstream target lipocalin-2 in the cell of origin in mice and humans, which leads to functional iron insufficiency in the aged cells. Genetic inactivation of the NUPR1-lipocalin-2 axis or iron supplementation rescues stemness and promotes the tumorigenic potential of aged alveolar cells. Conversely, targeting the NUPR1-lipocalin-2 axis is detrimental to young alveolar cells through ferroptosis induction. Ageing-associated DNA hypomethylation at specific enhancer sites is associated with increased NUPR1 expression, which is recapitulated in young alveolar cells through DNA methylation inhibition. We uncover that ageing drives functional iron insufficiency that leads to loss of stemness and tumorigenesis but promotes resistance to ferroptosis. These findings have implications for the therapeutic modulation of cellular iron homeostasis in regenerative medicine and in cancer prevention. Furthermore, our findings are consistent with a model whereby most human cancers initiate at a young age, thereby highlighting the importance of directing cancer prevention efforts towards young individuals.

Background A thorough analysis of genome evolution is fundamental for biodiversity understanding. The iconic monotremes (platypus and echidna) feature extraordinary biology. However, they also exhibit rearrangements in several chromosomes, especially in the sex chromosome chain. Therefore, the lack of a chromosome-level echidna genome has limited insights into genome evolution in monotremes, in particular the multiple sex chromosomes complex.Results Here, we present a new long reads-based chromosome-level short-beaked echidna (Tachyglossus aculeatus) genome, which allowed the inference of chromosomal rearrangements in the monotreme ancestor (2n = 64) and each extant species. Analysis of the more complete sex chromosomes uncovered homology between 1 Y chromosome and multiple X chromosomes, suggesting that it is the ancestral X that has undergone reciprocal translocation with ancestral autosomes to form the complex. We also identified dozens of ampliconic genes on the sex chromosomes, with several ancestral ones expressed during male meiosis, suggesting selective constraints in pairing the multiple sex chromosomes.Conclusion The new echidna genome provides an important basis for further study of the unique biology and conservation of this species.

We studied a family with three male individuals across two generations affected by common variable immune deficiency (CVID). We identified a novel missense heterozygous variant (c.2602T>A:p.Y868N) of NFKB2 in all patients and not in healthy relatives. Functional studies of the mutant allele in an overexpression system and of the patients' cells confirmed the deleteriousness of the NFKB2 variant and genotype, respectively, on the activation of the non-canonical NF-kappa B signaling pathway. Impaired processing of p100 into p52 underlies p100 accumulation, which results in gain-of-function (GOF) of I kappa B delta inhibitory activity and loss-of-function (LOF) of p52 transcriptional activity. The three patients' plasma contained autoantibodies that neutralized IFN-alpha 2 and/or IFN-omega, accounting for the severe or recurrent viral diseases of the patients, including influenza pneumonia in one sibling, and severe COVID-19 and recurrent herpes labialis in another. Our results confirm that NFKB2 alleles that are I kappa B delta GOF and p52 LOF can underlie CVID and drive the production of autoantibodies neutralizing type I IFNs, thereby predisposing to severe viral diseases.

Germinal centres are specialized microenvironments where B cells undergo affinity maturation. B cells expressing antibodies whose affinity is improved by somatic hypermutation are selected for expansion by limiting numbers of T follicular helper cells. Cell division is accompanied by mutation of the immunoglobulin genes, at what is believed to be a fixed rate of around 1 x 10-3 per base pair per cell division1. As mutagenesis is random, the probability of acquiring deleterious mutations outweighs the probability of acquiring affinity-enhancing mutations. This effect might be heightened, and even become counterproductive, in B cells that express high-affinity antibodies and undergo the greatest number of cell divisions2. Here we experimentally examine a theoretical model that explains how affinity maturation could be optimized by varying the rate of somatic hypermutation such that cells that express higher-affinity antibodies divide more but mutate less per division. Data obtained from mice immunized with SARS-CoV-2 vaccines or a model antigen align with the theoretical model and show that cells producing high-affinity antibodies shorten the G0/G1 phases of the cell cycle and reduce their mutation rates. We propose that these mechanisms safeguard high-affinity B cell lineages and enhance the outcomes of antibody affinity maturation.

Background: Treating rheumatic musculoskeletal diseases (RMDs) during pregnancy and breastfeeding presents significant complexities, mainly due to inconsistencies between the clinical guidance documents and the reference safety information, including the summary of product characteristics (SmPC) and the patient information leaflets (PIL).Objectives: To assess healthcare professionals' (HCPs) prescribing behaviors, comfort levels, and challenges when advising patients, focusing on discrepancies between clinical guidance documents and SmPC/PIL.Design: Online survey entitled PRAISE (Perception of healthcare providers Regarding Antirheumatics in pregnancy and breastfeeding: advice, Information and patient perSpEctives) and disseminated through HCPs groups and social media.Methods: A cross-sectional survey was conducted among 414 HCPs globally. Respondents were divided into prescribers (n = 336) and non-prescribers (n = 78) based on their self-reported role in prescribing antirheumatic medications to pregnant or breastfeeding patients with RMDs. The survey covered demographics, clinical experience, confidence in prescribing, use of clinical guidelines, and experiences managing conflicting information between guidelines and SmPC/PIL.Results: Prescribers were more likely than non-prescribers to feel comfortable discussing medication safety during pregnancy. Most prescribers found clinical guidance documents useful, with 48% rating them as "very useful" and 38% as "extremely useful." In case of conflicting information between clinical guidance documents and SmPC/PIL, 58% of HCPs reported that it caused confusion and tension in patient-doctor relationships, and almost 20% of them are "likely" or "very likely" to discontinue ongoing treatment. Clear communication and shared decision-making were the most common strategies used to address patient concerns.Conclusion: HCPs often face significant challenges when advising patients with RMDs on the use of medications during pregnancy and breastfeeding. Conflicting information between clinical guidance documents and SmPC/PIL can disrupt patient-doctor relationship and lead to treatment discontinuation, with potential consequences on maternal disease control. Improved alignment between clinical guidance documents and the SmPC/PIL could enhance patient care and prevent confusion among HCPs and patients.

A search is performed for charged-lepton flavor violating processes in top quark (t) production and decay. The data were collected by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 138 fb(-1). The selected events are required to contain one opposite-sign electron-muon pair, a third charged lepton (electron or muon), and at least one jet of which no more than one is associated with a bottom quark. Boosted decision trees are used to distinguish signal from background, exploiting differences in the kinematics of the final states particles. The data are consistent with the standard model expectation. Upper limits at 95% confidence level are placed in the context of effective field theory on the Wilson coefficients, which range between 0.024-0.424 TeV-2 depending on the flavor of the associated light quark and the Lorentz structure of the interaction. These limits are converted to upper limits on branching fractions involving up (charm) quarks, t -> e mu u (t -> e mu c), of 0.032(0.498) x 10(-6), 0.022(0.369) x 10(-6), and 0.012(0.216) x 10(-6) for tensorlike, vectorlike, and scalarlike interactions, respectively.

Metagenomics provides access to the genetic diversity of uncultured bacteria through analysis of DNA extracted from whole microbial communities. Long-read sequencing is advancing metagenomic discovery by generating larger DNA assemblies than previously possible. However, harnessing the potential of long-read sequencing to access the vast diversity within soil microbiomes is hampered by the challenge of isolating high-quality DNA. Here we introduce a method that can liberate large, high-quality metagenomic DNA fragments from soil bacteria and pair them with optimized nanopore long-read sequencing to generate megabase-sized assemblies. Using this method, we uncover hundreds of complete circular metagenomic genomes from a single soil sample. Through a combination of bioinformatic prediction and chemical synthesis, we convert nonribosomal peptide biosynthetic gene clusters directly into bioactive molecules, identifying antibiotics with rare modes of action and activity against multidrug-resistant pathogens. Our approach advances metagenomic access to the vast genetic diversity of the uncultured bacterial majority and provides a means to convert it to bioactive molecules.

Background Patients with psoriasis affecting a low percentage of their body surface area (BSA) are under-represented in clinical studies and may face substantial disease burden if high-impact sites are affected. Objectives To evaluate in a phase IIIb randomized placebo-controlled study (SPECTREM; NCT06039189) the efficacy and safety of guselkumab in participants with low BSA (2-15%), moderate [Investigator's Global Assessment (IGA) = 3] plaque psoriasis involving one or more high-impact site (scalp, face, genitals, intertriginous areas). Methods Eligible participants were randomized 2 : 1 to receive guselkumab 100 mg or placebo at week 0 and week 4, then every 8 weeks. The primary endpoint was the proportion of participants achieving IGA 0/1 (cleared/minimal) at week 16. Major secondary endpoints included the proportion of participants achieving >= 90% improvement in Psoriasis Area and Severity Index (PASI 90), IGA 0 and 100% improvement in PASI (PASI 100); mean percentage improvements from baseline to week 16 in BSA and PASI; and proportions of participants achieving site-specific IGA or Physician's Global Assessment (PGA) 0/1 among those with scalp, facial, genital or intertriginous site-specific IGA/PGA >= 3 at baseline. Results Among the 338 randomized participants (guselkumab, n = 225; placebo, n = 113), mean (SD) baseline BSA was 7.6% (3.7) and PASI was 9.0 (3.8). At week 16, all primary and major secondary endpoints were met, with guselkumab demonstrating superiority vs. placebo (all P < 0.001) in the proportions of participants achieving IGA 0/1 (74.2% vs. 12.4%), IGA 0 (40.4% vs. 3.5%), PASI 90 (52.9% vs. 6.2%) and PASI 100 (32.4% vs. 2.7%), and mean percentage improvement from baseline in BSA (80.6% vs. 6.1%) and PASI (82.6% vs. 13.7%). Site-specific IGA/PGA 0/1 response rates for guselkumab vs. placebo were as follows: scalp 75.0% (n = 114/152) vs. 14.5% (n = 11/76); face 87.8% (n = 79/90) vs. 28.6% (n = 12/42); genital 78.0% (n = 64/82) vs. 37.5% (n = 15/40) and intertriginous 86.5% (n = 96/111) vs. 28.8% (n = 15/52). In the guselkumab and placebo groups, respectively, 37.8% and 39.8% experienced one or more adverse event; no new safety signals were identified. Conclusions Through week 16, guselkumab was effective and well tolerated in participants with low BSA, moderate plaque psoriasis with involvement of high-impact sites. Statistically significant improvements across multiple clearance measures, irrespective of baseline BSA, support the effectiveness of guselkumab across a broad range of patients.

Assembly of actin-based stereocilia is critical for cochlear hair cells to detect sound. To tune their mechanosensivity, stereocilia form bundles composed of graded rows of ascending height, necessitating the precise control of actin polymerization. Myosin 15 (MYO15A) drives hair bundle development by delivering critical proteins to growing stereocilia that regulate actin polymerization via an unknown mechanism. Here, we show that MYO15A is itself an actin nucleation-promoting factor. Moreover, a deafness-causing mutation in the MYO15A actin-binding interface inhibits nucleation activity but still preserves some movement on filaments in vitro and partial trafficking on stereocilia in vivo. Stereocilia fail to elongate correctly in this mutant mouse, providing evidence that MYO15A-driven actin nucleation contributes to hair bundle biogenesis. Our work shows that in addition to generating force and motility, the ATPase domain of MYO15A can directly regulate actin polymerization and that disrupting this activity can promote cytoskeletal disease, such as hearing loss.