Chaturantabut et al. identify biparatopic FGFR2 antibodies that are effective against FGFR2 fusion–driven cholangiocarcinoma. The cover art depicts biparatopic antibodies binding to and crosslinking FGFR2, creating large complexes that promote FGFR2 internalization and degradation, which ultimately suppress tumor growth. Image credit: Behnoush Hajian and Mrinal Shekhar.
The presence of B cells is essential for the formation of CD8 T cell memory after infection and vaccination. In this study, we investigated whether B cells influence the programming of naïve CD8 T cells prior to their involvement in an immune response. RNA sequencing indicated that B cells are necessary for sustaining the FOXO1-controlled transcriptional program, which is critical for their homeostasis. Without an appropriate B cell repertoire, mouse naïve CD8 T cells exhibit a terminal, effector-skewed phenotype, which significantly impacts their response to vaccination. A similar effector-skewed phenotype with reduced FOXO1 expression was observed in naïve CD8 T cells from human patients undergoing B cell-depleting therapies. Furthermore, we show that patients without B cells have a defect in generating long-lived CD8 T cell memory following COVID vaccination. In summary, we demonstrate that B cells promote the quiescence of naïve CD8 T cells, poising them to become memory cells upon vaccination.
Cameron Manes, Miguel Guerrero Moreno, Jennifer Cimons, Marc A. D'Antonio, Tonya M. Brunetti, Michael G. Harbell, Sean Selva, Christopher Mizenko, Tyler L. Borko, Erika L. Lasda, Jay R. Hesselberth, Elena W.Y. Hsieh, Michael R. Verneris, Amanda L. Piquet, Laurent Gapin, Ross M. Kedl, Jared Klarquist
Fanconi anemia (FA) is a rare genetic disease characterized by loss-of-function variants in any of the 22 previously identified genes (FANCA-FANCW) that encode proteins participating in the repair of DNA interstrand crosslinks (ICLs). Patient phenotypes are variable, but may include developmental abnormalities, early onset pancytopenia, and predisposition to hematologic and solid tumors. Here, we describe two unrelated families with multiple pregnancy losses and offspring presenting with severe developmental and hematologic abnormalities leading to death in utero or in early life. Homozygous loss-of-function variants in FAAP100 were identified in affected children of both families. The FAAP100 protein associates with FANCB and FANCL, the E3 ubiquitin ligase responsible for the monoubiquitination of FANCD2 and FANCI, which is necessary for FA pathway function. Patient-derived cells exhibited phenotypes consistent with FA. Expression of the wild-type FAAP100 cDNA, but not the patient-derived variants, rescued the observed cellular phenotypes. This establishes FAAP100 deficiency as a cause of Fanconi anemia, with FAAP100 gaining an alias as FANCX. The extensive developmental malformations of individuals with FAAP100 loss-of-function variants are among the most severe across previously described FA phenotypes, indicating that the FA pathway is essential for human development.
Benjamin A. Harrison, Emma Mizrahi-Powell, John Pappas, Kristen Thomas, Subrahmanya Vasishta, Shripad Hebbar, Anju Shukla, Shalini S. Nayak, Tina K. Truong, Amy Woroch, Yara Kharbutli, Bruce D. Gelb, Cassie S. Mintz, Gilad D. Evrony, Agata Smogorzewska
Diffuse midline gliomas (DMGs) are lethal brain tumors characterized by p53-inactivating mutations and oncohistone H3.3K27M mutations that rewire the cellular response to genotoxic stress. We used RCAS/tv-a retroviruses and Cre recombinase to inactivate p53 and induce native H3.3K27M mutations in a lineage- and spatially-directed manner. We generated primary mouse tumors that recapitulate human DMG. Disrupting ataxia-telangiectasia mutated kinase (ATM) enhanced the efficacy of radiation therapy in murine and patient-derived DMG models which increased survival. Microscopy-based in situ sequencing was used to spatially resolve transcriptional profiles in >750,000 single cells with or without ATM disruption and radiation therapy, revealing altered immune-neoplastic and endothelial cell interactions after treatment. An allelic series of primary murine DMG models with different p53 mutations confirmed that transactivation-independent p53 activity is a key mediator of radiosensitivity after ATM disruption. Our findings contribute primary DMG mouse models with deep profiling and reveal the mechanisms of treatment response to an actionable therapeutic strategy.
Avani Mangoli, Vennesa Valentine, Spencer Maingi, Sophie R. Wu, Harrison Q. Liu, Michael Aksu, Vaibhav Jain, Bronwen E. Foreman, Joshua A. Regal, Loren B. Weidenhammer, Connor E. Stewart, Maria E. Guerra Garcia, Emily Hocke, Karen Abramson, Tal Michaeli, Nerissa T. Williams, Lixia Luo, Megan Romero, Katherine Deland, Samantha Gadd, Eita Uchida, Laura Attardi, Kouki Abe, Rintaro Hashizume, David M. Ashley, Oren J. Becher, David G. Kirsch, Simon G. Gregory, Zachary J. Reitman
The efficacy of T cell-activating therapies against glioma is limited by an immunosuppressive tumor microenvironment and tumor-induced T cell sequestration. We investigated whether peripherally infused non-antigen specific autologous lymphocytes (ALT) could accumulate in intracranial tumors. We observed that non-specific autologous CD8+ ALT cells can indeed accumulate in this context, despite endogenous T cell sequestration in bone marrow. Rates of intratumoral accumulation were markedly increased when expanding lymphocytes with IL-7 compared to IL-2. Pre-treatment with IL-7 ALT also enhanced the efficacy of multiple tumor-specific and non-tumor-specific T cell-dependent immunotherapies against orthotopic murine and human xenograft gliomas. Mechanistically, we detected increased VLA-4 on mouse and human CD8+ T cells following IL-7 expansion, with increased transcription of genes associated with migratory integrin expression (CD9). We also observed that IL-7 increases S1PR1 transcription in human CD8+ T cells, which we have shown to be protective against tumor-induced T cell sequestration. These observations demonstrate that expansion with IL-7 enhances the capacity of ALT to accumulate within intracranial tumors, and that pre-treatment with IL-7 ALT can boost the efficacy of subsequent T cell-activating therapies against glioma. Our findings will inform the development of future clinical trials where ALT pre-treatment can be combined with T cell-activating therapies.
Kirit Singh, Kelly M. Hotchkiss, Sarah L. Cook, Pamy Noldner, Ying Zhou, Eliese M. Moelker, Chelsea O. Railton, Emily E. Blandford, Bhairavy J. Puviindran, Shannon E. Wallace, Pamela K. Norberg, Gary E. Archer, Beth H. Shaz, Katayoun Ayasoufi, John H. Sampson, Mustafa Khasraw, Peter E. Fecci
Bardet-Biedl Syndrome (BBS), a ciliopathy characterized by obesity, hyperphagia, and learning deficits, arises from mutations in BBS genes. More exacerbated symptoms occur with mutations in genes encoding the BBSome, a complex regulating primary cilia function. We investigated the mechanisms underlying BBS-induced obesity using a novel BBS5 knockout (BBS5-/-) mouse model. BBS5-/- mice displayed hyperphagia, learning deficits, glucose/insulin intolerance, and disrupted metabolic hormones, phenocopying human BBS. They displayed an unique immunophenotype in white adipose tissue with increased proinflammatory macrophages and dysfunctional regulatory T cells, suggesting a distinct mechanism for adiposity compared to typical obesity models. Additionally, BBS5-/- mice exhibited pancreatic islet hyperplasia but failed to normalize blood glucose, suggesting defective insulin action. Hypothalamic transcriptomics revealed dysregulated endocrine signaling pathways with functional analyses confirming defects in insulin, leptin, and cholecystokinin (CCK) signalling, while preserving glucagon-like peptide-1 receptor (GLP-1R) responsiveness. Notably, treatment with a GLP-1R agonist effectively alleviated hyperphagia, body weight gain, improved glucose tolerance, and circulating metabolic hormones in BBS5-/- mice. This study establishes BBS5-/- mice as a valuable translational model of BBS to understand the pathogenesis and develop novel treatments. Our findings highlight the therapeutic potential of GLP-1R agonists for managing BBS-associated metabolic dysregulation, warranting further investigation for clinical application.
Arashdeep Singh, Naila Haq, Mingxin Yang, Shelby Luckey, Samira Mansouri, Martha Campbell-Thompson, Lei Jin, Sofia Christou-Savina, Guillaume de Lartigue
Metabolic dysfunction associated steatotic liver disease (MASLD, formerly called NAFLD) and its more advanced form, metabolic dysfunction associated steatohepatitis (MASH, formerly called NASH) are increasing in prevalence worldwide as the number of individuals with metabolic risk factors rises. These diseases and their adverse sequelae have a formidable economic impact, and there remain large gaps in understanding and treating MASLD/MASH. Series editor Scott Friedman curated this series of expert-led review articles to cover advances and challenges across the spectrum of basic investigation to clinical trials. The reviews will address diagnostic approaches, management strategies specific to adolescent and pregnant individuals, pathobiology, and therapeutic horizons, with the goal of reflecting the heterogeneity seen in disease drivers as well as the affected population.
×