The rockefeller university

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.

The SARS-CoV-2 pandemic underscored the need for innovative approaches to study humoral immunity and isolate monoclonal antibodies (mAbs) with diagnostic and therapeutic potential. Current methods for repertoire analysis at the clonal level require large-scale recombinant mAb production, limiting accessibility and delaying functional insight. We developed a single-cell culture (SCC) platform that enables profiling of human memory B cells and direct recovery of functional mAbs. Using samples from COVID-19 convalescent and vaccinated donors, we optimized SCCs with NB21 feeder cells, R848, and IL-2, achieving efficient clonal expansion and antibody secretion in short-term cultures. Screening and pseudovirus neutralization assays were performed directly with culture supernatants, bypassing the need for early recombinant antibody production. Antigen-baited cytometry sorting enriched spike-specific memory B cells by similar to 30-fold. Among 592 isolated mAbs, 53% bound the Wuhan spike, targeting the receptor-binding domain (28%), N-terminal domain (15%), or other regions (57%). Cross-reactivity analysis revealed that 40% of anti-spike mAbs recognized all tested variants of concern. VH/VL sequencing uncovered convergent rearrangements, including public V3-30 and V3-53/V3-66 clones, consistent with global findings. Two public receptor-binding domain-specific antibodies demonstrated broad neutralization when produced recombinantly. Together, these results validate the SCC system as a streamlined approach for unbiased repertoire analysis and functional mAb isolation. More broadly, the platform provides a practical framework for linking B cell clonal composition with antigen specificity and serum antibody responses. By reducing costs and simplifying workflows, it expands opportunities for antibody discovery and immunoepidemiological studies, fostering wider global participation in therapeutic antibody research.

A major challenge in the development of more effective therapeutic strategies for Alzheimer's disease (AD) is the identification of molecular mechanisms linked to specific pathophysiological features of the disease. Importantly AD has a two-fold higher incidence in women than men and a protracted prodromal phase characterized by amnestic mild-cognitive impairment (aMCI) suggesting that biological processes occurring early can initiate vulnerability to AD. Here, we used a sample of 125 subjects from two independent study cohorts to determine the levels in plasma (the most accessible specimen) of two essential mitochondrial markers acetyl-L-carnitine (LAC) and its derivative free-carnitine motivated by a mechanistic model in rodents in which targeting mitochondrial metabolism of LAC leads to the amelioration of cognitive function and boosts epigenetic mechanisms of gene expression. We report a sex-specific deficiency in free-carnitine levels in women with aMCI and early-AD compared to cognitively healthy controls; no change was observed in men. We also replicated the prior finding of decreased LAC levels in both women and men with AD, supporting the robustness of the study samples assayed in our new study. The magnitude of the sex-specific free-carnitine deficiency reflected the severity of cognitive dysfunction and held in two study cohorts. Furthermore, patients with the lower free-carnitine levels showed higher beta-amyloid(A beta) accumulation and t-Tau levels assayed in cerebrospinal fluid (CSF). Computational analyses showed that the mitochondrial markers assayed in plasma are at least as accurate as CSF measures to classify disease status. Together with the mechanistic platform in rodents, these translational findings lay the groundwork to create preventive individualized treatments targeting sex-specific changes in mitochondrial metabolism that may be subtle to early cognitive dysfunction of AD risk.

G protein-coupled receptors (GPCRs) are a superfamily of transmembrane signal transducers that facilitate the flow of chemical signals across membranes. GPCRs are a desirable class of drug targets, and the activation and deactivation dynamics of these receptors are widely studied. Multidisciplinary approaches for studying GPCRs, such as downstream biochemical signaling assays, cryo-electron microscopy structural determinations, and molecular dynamics simulations, have provided insights concerning conformational dynamics and signaling mechanisms. However, new approaches including biosensors that use luminescence- and fluorescence-based readouts have been developed to investigate GPCRrelated protein interactions and dynamics directly in cellular environments. Luminescence- and fluorescence-based readout approaches have also included the development of GPCR biosensor platforms that utilize enabling technologies to facilitate multiplexing and miniaturization. General principles underlying the biosensor platforms and technologies include scalability, orthogonality, and kinetic resolution. Further application and development of GPCR biosensors could facilitate hit identification in drug discovery campaigns. The goals of this review are to summarize developments in the field of GPCR-related biosensors and to discuss the current available technologies.

In the course of antibody affinity maturation, germinal centre (GC) B cells mutate their immunoglobulin heavy- and light-chain genes in a process known as somatic hypermutation (SHM)1, 2, 3-4. Panels of mutant B cells with different binding affinities for antigens are then selected in a Darwinian manner, which leads to a progressive increase in affinity among the population5. As with any Darwinian process, rare gain-of-fitness mutations must be identified and common loss-of-fitness mutations avoided6. Progressive acquisition of mutations therefore poses a risk during large proliferative bursts7, when GC B cells undergo several cell cycles in the absence of affinity-based selection8, 9, 10, 11, 12-13. Using a combination of in vivo mouse experiments and mathematical modelling, here we show that GCs achieve this balance by strongly suppressing SHM during clonal-burst-type expansion, so that a large fraction of the progeny generated by these bursts does not deviate from their ancestral genotype. Intravital imaging and image-based cell sorting of a mouse strain carrying a reporter of cyclin-dependent kinase 2 (CDK2) activity showed that B cells that are actively undergoing proliferative bursts lack the transient CDK2low 'G0-like' phase of the cell cycle in which SHM takes place. We propose a model in which inertially cycling B cells mostly delay SHM until the G0-like phase that follows their final round of division in the GC dark zone, thus maintaining affinity as they clonally expand in the absence of selection.

Aneuploidy in embryos poses a major barrier to successful human reproduction, contributing to nearly 50% of early miscarriages. Despite its high prevalence in human embryos, the molecular mechanisms regulating aneuploid cell fate during development remain poorly understood. This knowledge gap persists due to ethical constraints in human embryo research and the limitations of existing animal models. In this study, we identified the New World primate marmoset (Callithrix jacchus) as a suitable model for investigating aneuploidy. By calling copy number variants from single-cell RNA-sequencing data of marmoset embryonic cells, we identified heterogeneous aneuploidy, indicating chromosomal instability (CIN) in marmoset preimplantation embryos. Furthermore, marmoset aneuploidy displayed lineage-specific behavior during gastruloid differentiation, similar to humans, suggesting a conserved regulatory mechanism in lineage specification. To develop a more pluripotent cell line to study early specification, we established an efficient approach for generating na & iuml;ve-like marmoset pluripotent stem cells (cjPSCs). These cells resemble preimplantation epiblast-like cells and exhibit inherent CIN. Transcriptome analysis identified potential pathways contributing to aneuploidy during early embryogenesis, including the downregulation of cell cycle checkpoint signaling and the upregulation of autophagy pathways. Additionally, we found no significant effect of spontaneously occurring aneuploidy in cjPSCs on blastoid formation, suggesting that the consequences of aneuploidy become evident only after gastrulation, with preimplantation lineages exhibiting a higher tolerance for genomic instability. Unexpectedly, aneuploidy enhanced cavity formation during blastoid development, suggesting a potential role in facilitating efficient trophectoderm differentiation. Our findings validate the marmoset as a valuable model for studying CIN during early primate development and provide insight into the mechanisms underlying the prevalence of aneuploidy in primates. Na & iuml;ve-like cjPSCs recapitulate key phenotypic traits of early embryonic cells, providing a robust system for studying post-implantation aneuploid cell fates in vivo and serving as a foundation for future research in this field.

To elucidate aging-associated cellular population dynamics, we present PanSci, a single-cell transcriptome atlas profiling >20 million cells from 623 mouse tissues across different life stages, sexes, and genotypes. This comprehensive dataset reveals >3000 different cellular states and >200 aging-associated cell populations. Our panoramic analysis uncovered organ-, lineage-, and sex-specific shifts in cellular dynamics during life-span progression. Moreover, we identify both systematic and organ-specific alterations in immune cell populations associated with aging. We further explored the regulatory roles of the immune system on aging and pinpointed specific age-related cell population expansions that are lymphocyte dependent. Our "cell-omics" strategy enhances comprehension of cellular aging and lays the groundwork for exploring the complex cellular regulatory networks in aging and aging-associated diseases.

Spinal cord injury (SCI) is a devastating condition with 250,000 to 500,000 new cases globally each year. Respiratory infections, e.g., pneumonia and influenza are the leading cause of death after SCI. Unfortunately, there is a poor understanding of how altered neuro-immune communication impacts an individual's outcome to infection. In humans and rodents, SCI leads to maladaptive changes in the spinal-sympathetic reflex (SSR) circuit which is crucial to sympathetic function. The cause of the impaired immune function may be related to harmful neuroinflammation which is detrimental to homeostatic neuronal function, aberrant plasticity, and hyperexcitable circuits. Soluble tumor necrosis factor (sTNF) is a pro-inflammatory cytokine that is elevated in the CNS after SCI and remains elevated for several months after injury. By pharmacologically attenuating sTNF in the CNS after SCI we were able to demonstrate improved immune function. Furthermore, when we investigated the specific cellular population which may be involved in altered neuro-immune communication we reported that excessive TNFR1 activity on excitatory INs promotes immune dysfunction. Furthermore, this observation is NFk beta dependent in VGluT2 + INs. Our data is the first report of a target within the CNS, TNFR1, that contributes to SCI-induced immune dysfunction after T9-SCI and is a potential avenue for future therapeutics.