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Abstract
Epstein-Barr virus (EBV) is of growing interest for its potential role in neurodegenerative diseases such as multiple sclerosis (MS) and its possible utility as a therapeutic target in herpesvirus-associated chronic diseases. The effects of brincidofovir (BCV) on EBV reactivation were evaluated in vitro using EBV-infected spontaneous lymphoblastoid cell lines (SLCLs) and peripheral blood mononuclear cells (PBMCs) derived from MS patients and healthy controls. In addition, a B lymphoblastoid cell line and PBMCs from common marmosets (Callithrix jacchus) naturally infected with an EBV-related gammaherpesvirus (Callitrichine herpesvirus 3, CalHV-3) were used to measure BCV efficacy in a nonhuman primate model. BCV significantly inhibited gammaherpesvirus reactivation, with decreased lytic and latent viral transcript expression. These results suggest that BCV may be a useful antiviral for inhibiting EBV activity in MS patients. Additionally, this work further validates the utility of CalHV-3 in marmosets as a translational model for the investigation of successful EBV-targeting therapeutics.
Authors
Abaigeal Donaldson, Madeleine R. Druker, Maria Chiara Monaco, Emily H. Stack, Paige Zimmerman, Amanda Lee, Izabela Bialuk, William Frazier, Irene Cortese, Heather Narver, Masatoshi Hazama, Fuminori Yoshida, Xiaofan Li, Laurie T. Krug, Stacey L. Piotrowski, Steven Jacobson
Abstract
Acute myeloid leukemia (AML) is an aggressive cancer with very poor outcomes. To identify additional drivers of leukemogenesis, we analyzed sequencing data from 1,727 unique individual AML patients, which revealed mutations in ubiquitin ligase family genes in 11.2% of adult AML samples with mutual exclusivity. The SKP1/CUL1/F-box (SCF) E3 ubiquitin ligase complex gene, FBXO11, was the most significantly downregulated gene of the SCF complex in AML. We found that FBXO11 interacts with and catalyzes K63-linked ubiquitination of LONP1 in the cytosol, to promote LONP1 entry into mitochondria. We show that depletion of FBXO11 or LONP1 reduces mitochondrial respiration through impaired LONP1 chaperone activity to assemble electron transport chain Complex IV. Reduced mitochondrial respiration secondary to FBXO11 or LONP1 depletion imparted myeloid-biased stem cell properties in primary CD34+ hematopoietic stem and progenitor cells (HSPC) in vitro. In a human xenograft model, depletion of FBXO11 cooperated with AML1-ETO and mutant KRASG12D to generate serially transplantable AML. Our findings suggest that reduced FBXO11 cooperates to initiate AML by priming HSPC for myeloid-biased self-renewal through attenuation of LONP1-mediated regulation of mitochondrial respiration.
Authors
Hayle Kincross, Ya-Chi Angela Mo, Xuan Wang, Linda Chang, Gerben Duns, Franziska Mey, Jihong Jiang, Zurui Zhu, Naomi Isak, Harwood Kwan, Tammy T.Y. Lau, T. Roderick Docking, Pranav Garg, Jessica Tran, Shane Colborne, Se-Wing Grace Cheng, Shujun Huang, Nadia Gharaee, Elijah Willie, Jeremy D.K. Parker, Joshua Bridgers, Davis Wood, Ramon I. Klein Geltink, Gregg B. Morin, Aly Karsan
Abstract
Authors
Antonio Carlos Tallon-Cobos, Konstantinos Vazaios, Piotr Waranecki, Marliek van Hoesel, Annelisa M. Cornel, Benjamin Schwalm, Norman Mack, Ella de Boed, Jasper van der Lugt, Stefan Nierkens, Marcel Kool, Eelco W. Hoving, Dennis S. Metselaar, Esther Hulleman
Abstract
Authors
Alexander M. Loiben, Wei-Ming Chien, Ashley McKinstry, Dania Ahmed, Matthew C. Childers, Michael Regnier, Charles E. Murry, Kai-Chun Yang
Abstract
BACKGROUND. Cardiac allograft vasculopathy (CAV) is consistently accompanied by immune infiltrates surrounding affected coronary arteries, including antibody-producing plasma cells (PC). The antigenic drivers of these intragraft PC responses remain poorly defined. METHODS. We characterized graft-infiltrating PC by single-cell RNA sequencing and immunoglobulin gene profiling. Using immunoglobulin sequences we generated 37 recombinant monoclonal antibodies (mAb) from dominant intragraft PC clones and 24 control mAb from peripheral blood PC. Antigen reactivity was screened against chemical adducts, including bilirubin, a heme-degradation by-product. Histologic and tissue analyses assessed bilirubin deposition as well as expression of heme-catabolic enzymes, and the presence of Fe2+ in heart explants with CAV. RESULTS. A majority of graft-derived mAb (21/37; ~57%) but none of the mAb derived from blood PC reacted to bilirubin. Bilirubin deposition was detected within lymphocytic aggregates in CAV grafts. In coronary arteries with CAV lesions, bilirubin accumulated in the cytoplasm and nuclei of smooth muscle cells in the tunica media, a pattern not observed in healthy heart tissue. Lastly, we detected the expression of heme-oxygenase-1 and biliverdin reductases in graft-infiltrating macrophages along with the presence of Fe2+ ion in the media of arteries with hyperplasia. CONCLUSION. These findings suggest that local heme catabolism and resultant bilirubin accumulation create a prominent target for intragraft antibody responses in CAV. Bilirubin-specific antibodies and heme-catabolic pathways may contribute to CAV pathogenesis and represent potential mechanistic and therapeutic avenues for further investigation. FUNDING. National Institute of Health.
Authors
Sarah B. See, Talita Aguiar, Max Dietzel, Mattea Ausmeier, Hang T.T. Nguyen, Shunya Mashiko, Laura Donadeu, Hector Cordero, Poulomi Roy, Lorea Roson, Charles C. Marboe, Matthias J. Szabolcs, Maryjane Farr, Jose González-Costello, Aleix Olivella, Yoshifumi Naka, Koji Takeda, Rodica Vasilescu, Kevin J. Clerkin, Gilles Benichou, Joren C. Madsen, R. Glenn King, Oriol Bestard, Evan P. Kransdorf, Emmanuel Zorn
Abstract
Disorders of GABRA3, the only epilepsy-associated GABA-A receptor subunit gene on the X chromosome, have eluded clinical clarity due to ambiguous inheritance patterns and variable phenotypes. The long-standing assumption that all pathogenic variants cause loss-of-function further obscured genotype-phenotype relationships and hindered progress. Here, we curated a cohort of individuals with a GABRA3 variant, integrating deep phenotyping, genotyping, family history, electrophysiology, with a targeted mouse model. Among 43 individuals with 19 GABRA3 variants, functional analyses revealed both gain- and loss-of-function effects, each linked to distinct clinical profiles. Gain-of-function variants were associated with severe, treatment-resistant epilepsy and severe-profound intellectual disability, disproportionately affecting males, who were often non-ambulant and had cortical visual impairment. Loss-of-function variants produced milder phenotypes, with epilepsy rarely observed; affected males showed behavioural issues and language delay, while females were unaffected carriers. Our gain-of-function (Gabra3Q242L/+) mouse model mirrored these sex-specific differences, showing increased seizure susceptibility, early death, and marked cortical hyperexcitability. These insights not only resolve longstanding uncertainties surrounding GABRA3 but also redefine how X-linked disorders are interpreted. They demonstrate that it is the functional impact of a variant, not its mere presence, that determines whether a condition manifests dominantly or recessively. This distinction carries important implications for genetic counselling, precision medicine, and the broader interpretation of X-linked neurodevelopmental disorders.
Authors
Katrine M. Johannesen, Khaing Phyu Aung, Vivian W.Y. Liao, Nathan L. Absalom, Han C. Chua, Xue N. Gan, Miaomiao Mao, Chaseley E. McKenzie, Hian M. Lee, Sebastian Ortiz, Rebecca C. Spillmann, Vandana Shashi, Rodney A. Radtke, Ghayda M. Mirzaa, P. Anne Weisner, Josue Flores Daboub, Caroline Hagedorn, Pinar Bayrak-Toydemir, Desiree DeMille, Jian Zhao, Nandita Bajaj, Yline Capri, Boris Keren, Miriam Schmidts, Ingrid M.B.H. van de Laar, Marjon A. van Slegtenhorst, Rafal Ploski, Marta Bogotko, Danielle K. Bourque, Ebba Alkhunaizi, Lauren Chad, Nada Quercia, Houda Elloumi, Ingrid M. Wentzensen, Michael C. Kruer, Pritha Bisarad, Carolina I. Galaz-Montoya, Violeta Rusu, Dominique Braun, Katie Angione, Jessica C. Win, Camilo Espinosa-Jovel, Pia Zacher, Konrad Platzer, Samuel F. Berkovic, Ingrid E. Scheffer, Mary Chebib, Guido Rubboli, Rikke S. Møller, Christopher A. Reid, Philip K. Ahring
Abstract
Hormone Receptor positive (HR+) breast cancers (BC) are typically “immune-cold” poorly immune infiltrated tumors that do not respond to immune-checkpoint blockade (ICB) therapies. Using clinical data, we report that estrogen receptor (ERα) signaling associates with immunosuppressive pathways and lack of response to ICB in HR+ patients. In this study, we validate ER-mediated immunosuppression by engineering and modulating ER in preclinical models in vitro, in vivo and ex vivo. Mechanistically, we found that ERα hijacks LCOR, a nuclear receptor corepressor, thereby preventing LCOR’s function in the induction of tumor immunogenicity and immune infiltration, which is normally observed in the absence of ERα, such as in ER-negative BC. In HR+BC, we demonstrate that the molecular disruption of LCOR and ERα interaction using anti-ER therapies or using a mutant of the LCOR nuclear-receptor binding domain (LSKLL into LSKAA) that does not interact with ERα, restores LCOR’s immunogenic functions. Remarkably, the LCOR-ERα disruption converts HR+BC immune-cold tumors into immune-hot tumors responsive to ICB by increased antigen presentation machinery (APM) expression, immune infiltration, T cell recognition and mediated killing. In conclusion, ERα inhibition and the disruption of LCOR to ERα represent a novel therapeutic strategy and an opportunity to elicit immunotherapeutic benefit in HR+BC patients.
Authors
José Ángel Palomeque, Gabriel Serra-Mir, Sandra Blasco-Benito, Helena Brunel, Pau Torren-Duran, Iván Pérez-Núñez, Chiara Cannatá, Laura Comerma, Silvia Menendez, Sonia Servitja, Tamara Martos, Maria Castro, Rodrigo L. Borges, Joanna I. Lopez-Velazco, Sara Manzano, Santiago Duro-Sánchez, Joaquin Arribas, Maria M. Caffarel, Ander Urruticoechea, Jose A. Seoane, Lluis Morey, Joan Albanell, Toni Celià-Terrassa
Abstract
BACKGROUND. Checkpoint inhibitor-associated autoimmune diabetes (CIADM) is a rare but life-altering complication of immune checkpoint inhibitor (ICI) therapy. Biomarkers that predict type 1 diabetes (T1D) are unreliable for CIADM. AIM. To identify biomarkers for prediction of CIADM. METHODS. From our prospective biobank, 14 CIADM patients who had metastatic melanoma treated with anti-PD-1 ± anti-CTLA4 were identified. Controls were selected from the same biobank, matched 2:1. Pre-treatment, on-ICI and post-CIADM serum and peripheral blood mononuclear cells (PBMCs) were analysed. Serum was analysed for T1D autoantibodies, C-peptide, glucose and cytokines. PBMCs were profiled using flow cytometry. Pancreatic volume was measured using CT volumetry. RESUTLS. Before treatment, CIADM patients had smaller pancreatic volume (27% reduction, p=0.044) and higher anti-GAD antibody titres (median 2.9 versus 0, p=0.01). They had significantly higher baseline proportions of Th17 helper cells (p=0.03), higher CD4+ central memory cells (p=0.04) and lower naïve CD4+ cells (p=0.01). With ICI treatment, greater declines in pancreatic volume were seen in CIADM patients (p<0.0001). Activated CD4+ subsets increased significantly in CIADM and controls with immune-related adverse effects (IRAE) but not controls without IRAE. Using only pre-treatment results, pancreatic volume, anti-GAD antibody titre and baseline immune flow profile were highly predictive of CIADM development, with an area under the curve (AUC) of >0.96. CONCLUSIONS. People who develop CIADM are immunologically predisposed and have antecedent pancreatic and immunological changes that accurately predict disease with excellent sensitivity. These biomarkers could be used to guide ICI use, particularly when planning treatment for low-risk tumours. FUNDING. JEG is supported by NHMRC Investigator grant 2033228. AMM by NHMRC Investigator grant 2009476 and GVL by NHMRC Investigator grant 2007839.
Authors
Linda Wu, John M. Wentworth, Christopher Liddle, Nicole Fewings, Matteo Carlino, David A. Brown, Roderick Clifton-Bligh, Georgina V. Long, Richard A. Scolyer, Nicholas Norris, Sarah C. Sasson, Venessa H.M. Tsang, Alexander M. Menzies, Jenny E. Gunton
Abstract
Authors
Amit Prabhakar, Eckart M.D.D. De Bie, Jacqueline T. DesJardin, Prajakta Ghatpande, Stefan Gräf, Luke S. Howard, S. John Wort, Colin Church, David G. Kiely, Emily Sumpena, Thin Aung, Shenrae Carter, Jasleen Kukreja, Steven Hays, John R. Greenland, Jonathan P. Singer, Michael Wax, Paul J. Wolters, Marc A. Simon, Mark Toshner, Giorgio Lagna, Akiko Hata
Abstract
In pancreatic β-cells, misfolded proinsulin is a substrate for Endoplasmic Reticulum-Associated protein Degradation (ERAD) via HRD1/SEL1L. β-cell HRD1 activity is alternately reported to improve, or impair, insulin biogenesis. Further, while β-cell SEL1L deficiency causes HRD1 hypofunction and diminishes islet insulin content; reports conflict as to whether β-cell ERAD deficiency increases or decreases proinsulin levels. Here we’ve examined β-cell-specific Hrd1-KO mice (chronic deficiency), plus rodent (and human islet) β-cells treated acutely with HRD1 inhibitor. β-Hrd1-KO mice developed diabetes with decreased islet proinsulin yet a relative increase of misfolded proinsulin re-distributed to the ER; upregulated biochemical markers of β-cell ER stress and autophagy; electron microscopic evidence of ER enlargement and decreased insulin granule content; and increased glucagon-positive islet cells. Misfolded proinsulin was also increased in islets treated with inhibitors of lysosomal degradation. Preceding any loss of total proinsulin, acute HRD1 inhibition triggered increased nonnative proinsulin, increased phospho-eIF2ɑ with inhibited proinsulin synthesis, and increased LC3b-II (the abundance of which requires expression of SigmaR1). We posit a subset of proinsulin molecules undergoes HRD1-mediated disposal. When HRD1 is unavailable, misfolded proinsulin accumulates, accompanied by increased phospho-eIF2ɑ that limits further proinsulin synthesis, plus SigmaR1-dependent autophagy activation, ultimately lowering steady-state β-cell proinsulin (and insulin) levels — triggering diabetes.
Authors
Anoop Arunagiri, Leena Haataja, Maroof Alam, Noah F. Gleason, Emma Mastroianni, Chao-Yin Cheng, Sami Bazzi Onton, Jeffrey Knupp, Ibrahim Metawea, Anis Hassan, Dennis Larkin, Deyu Fang, Billy Tsai, Ling Qi, Peter Arvan
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ISSN: 0021-9738 (print), 1558-8238 (online)