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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
Abstract
While immune checkpoint blockade (ICB) therapy has revolutionized the antitumor therapeutic landscape, it remains successful in only a small subset of cancer patients. Poor or loss of MHC-I expression has been implicated as a common mechanism of ICB resistance. Yet the molecular mechanisms underlying impaired MHC-I remain to be fully elucidated. Herein, we identified USP22 as a critical factor responsible for ICB resistance through suppressing MHC-I-mediated neoantigen presentation to CD8 T cells. Both genetic and pharmacologic USP22 inhibition increased immunogenicity and overcome anti-PD-1 immunotherapeutic resistance. At the molecular level, USP22 functions as a deubiquitinase for the methyltransferase EZH2, leading to transcriptional silencing of MHC-I gene expression. Targeted Usp22 inhibition resulted in increased tumoral MHC-I expression and consequently enhanced CD8 T cell killing, which was largely abrogated by Ezh2 reconstitution. Multiplexed immunofluorescence staining detected a strong reverse correlation between USP22 expression and both 2M expression and CD8+ T lymphocyte infiltration in solid tumors. Importantly, USP22 upregulation was associated with ICB immunotherapeutic resistance in patients with lung cancer. Collectively, this study highlights the role of USP22 as a diagnostic biomarker for ICB resistance and provides a potential therapeutic avenue to overcome the current ICB resistance through inhibition of USP22.
Authors
Kun Liu, Radhika Iyer, Yi Li, Jun Zhu, Zhaomeng Cai, Juncheng Wei, Yang Cheng, Amy Tang, Hai Wang, Qiong Gao, Nikita Lavanya Mani, Noah Marx, Beixue Gao, D. Martin Watterson, Seema A. Khan, William J. Gradishar, Huiping Liu, Deyu Fang
Abstract
11-cis-Retinal is essential for light perception in mammalian photoreceptors (PRs), and aberrations in retinoid transformations cause severe retinal diseases. Understanding these processes is crucial for combating blinding diseases. The visual cycle, operating within PRs and the retinal pigment epithelium (RPE), regenerates 11-cis-retinal to sustain light sensitivity. Retinoids are also present in Müller glia (MG), hypothesized to supply 11-cis-retinol to cone PRs and retinal ganglion cells (RGCs). To trace retinoid movement through retinal cell types, we used cell-specific knock-in of lecithin:retinol acyltransferase (LRAT), which converts retinols into stable retinyl esters (REs). Ectopic LRAT expression in murine PRs, MG, and RGCs resulted in RE synthesis, with REs differing in abundance and isomeric composition across cell types under genetic and light-based perturbations. PR inner segments showed high 11-cis-RE content, suggesting a constant 11-cis-retinoid supply for pigment regeneration. In MG expressing LRAT, all-trans-REs were detected, contrasting with 11-cis-REs in PRs. The MG-specific LRAT phenotype mirrored the RE-rich human neural retina, suggesting human MG may utilize LRAT to maintain retinoid reservoirs. Our findings reveal tightly controlled retinoid flux throughout the mammalian retina supporting sustained vision, expanding understanding of the visual cycle to combat retinal diseases.
Authors
Zachary J. Engfer, Grazyna Palczewska, Samuel W. Du, Jianye Zhang, Zhiqian Dong, Carolline Rodrigues Menezes, Jun Wang, Jianming Shao, Budd A. Tucker, Robert F. Mullins, Rui Chen, Philip D. Kiser, Krzysztof Palczewski
Abstract
N6-methyladenosine (m6A), the most predominant RNA modification in humans, participates in various fundamental and pathological bioprocesses. Dynamic manipulation of m6A deposition in the transcriptome is critical for cancer progression, while how this regulation is achieved remains understudied. Here, we report that in prostate cancer (PCa), Polycomb group (PcG) protein Enhancer of Zeste Homolog 2 (EZH2) exerts an additional function in m6A regulation via its enzymatic activity. Mechanistically, EZH2 methylates and stabilizes FOXA1 proteins from degradation, which in turn facilitates the transcription of m6A reader YTHDF1. Through activating an m6A autoregulation pathway, YTHDF1 enhances the translation of METTL14 and WTAP, two critical components of the m6A methyltransferase complex (MTC), and thereby upregulates the global m6A level in PCa cells. We further demonstrate that inhibiting the catalytic activity of EZH2 suppresses the translation process globally through targeting the YTHDF1-m6A axis. By disrupting both the expression and interaction of key m6A MTC subunits, combinational treatment of EZH2 degrader MS8815 and m6A inhibitor STM2457 mitigates prostate tumor growth synergistically. Together, our study decodes a previously hidden interrelationship between EZH2 and mRNA modification, which may be leveraged to advance the EZH2-targeting curative strategies in cancer.
Authors
Yang Yi, Joshua Fry, Chaehyun Yum, Rui Wang, Siqi Wu, Sharath Narayan, Qi Liu, Xingxing Zhang, Htoo Zarni Oo, Ning Xie, Yanqiang Li, Xinlei Gao, Xufen Yu, Xiaoping Hu, Qiaqia Li, Kemal Keseroglu, Ertuğrul M. Özbudak, Sarki A. Abdulkadir, Kaifu Chen, Jian Jin, Jonathan C. Zhao, Xuesen Dong, Daniel Arango, Rendong Yang, Qi Cao
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ISSN: 0021-9738 (print), 1558-8238 (online)