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High 4E-BP-1 expression associates with chromosome 8 gain and CDK4/6 sensitivity in Ewing Sarcoma

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Abstract

Chromosome 8 (chr8) gains are common in cancer, but their contribution to tumor heterogeneity is largely unexplored. Ewing sarcoma (EwS) is defined by FET::ETS fusions with few other recurrent mutations to explain clinical diversity. In EwS, chr8 gains are the second most frequent alteration, making it an ideal model to study their relevance in an otherwise silent genomic context. We report that chr8 gain-driven expression patterns correlate with poor overall survival of EwS patients. This effect is mainly mediated by increased expression of the translation initiation factor binding protein 4E-BP1, encoded by EIF4EBP1 on chr8. Among all chr8-encoded genes, EIF4EBP1 expression showed the strongest association with poor survival and correlated with chr8 gains in EwS tumors. Similar findings emerged across multiple TCGA cancer entities. Multi-omics profiling revealed that 4E-BP1 orchestrates a pro-proliferative proteomic network. Silencing 4E-BP1 reduced proliferation, clonogenicity, spheroidal growth in vitro, and tumor growth in vivo. Drug screens demonstrated that high 4E-BP1 expression sensitizes EwS to pharmacological CDK4/6-inhibition. Chr8 gains and elevated 4E-BP1 emerge as prognostic biomarkers in EwS, with poor outcomes driven by 4E-BP1-mediated pro-proliferative networks that sensitize tumors to CDK4/6 inhibitors. Testing for chr8 gains may enhance risk stratification and therapy in EwS and other cancers.

Authors

Cornelius M. Funk, Anna C. Ehlers, Martin F. Orth, Karim Aljakouch, Jing Li, Tilman L.B. Hoelting, Rainer Will, Florian H. Geyer, A. Katharina Ceranski, Franziska Willis, Endrit Vinca, Shunya Ohmura, Roland Imle, Jana Siebenlist, Angelina Yershova, Maximilian M.L. Knott, Felina Zahnow, Ana Sastre, Javier Alonso, Felix Sahm, Heike Peterziel, Anna Loboda, Martin Schneider, Ana Banito, Gabriel Leprivier, Wolfgang Hartmann, Uta Dirksen, Olaf Witt, Ina Oehme, Stefan M. Pfister, Laura Romero-Pérez, Jeroen Krijgsveld, Florencia Cidre-Aranaz, Thomas G.P. Grünewald, Julian Musa

A positive allosteric modulator of the β₁AR with antagonist activity for catecholaminergic polymorphic ventricular tachycardia

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Abstract

Orthosteric β-blockers represent the leading pharmacological intervention for managing heart diseases owing to their ability to competitively antagonize β-adrenergic receptors (βARs). However, their use is often limited by the development of adverse effects such as fatigue, hypotension, and reduced exercise capacity, due in part to the nonselective inhibition of multiple βAR subtypes. These challenges are particularly problematic in treating catecholaminergic polymorphic ventricular tachycardia (CPVT), a disease characterized by lethal tachyarrhythmias directly triggered by cardiac β1AR activation. To identify small molecule allosteric modulators of the β1AR that could offer enhanced subtype specificity and robust functional antagonism of β1AR-mediated signaling, we conducted a DNA-encoded small molecule library screen and discovered Compound 11 (C11). C11 selectively potentiates the binding affinity of orthosteric agonists to the β1AR while potently inhibiting downstream signaling following β1AR activation. Moreover, C11 prevents agonist-induced spontaneous contractile activity, Ca2+ release events, and exercise-induced ventricular tachycardia in the CSQ2–/– murine model of CPVT. Collectively, our studies demonstrate that C11 belongs to an emerging class of allosteric modulators termed PAM-antagonists that positively modulate agonist binding but block downstream function. With unique pharmacological properties and selective functional antagonism of β1AR-mediated signaling, C11 represents a promising therapeutic candidate for the treatment of CPVT and other forms of cardiac disease associated with excessive β1AR activation.

Authors

Alyssa Grogan, Robin M. Perelli, Seungkirl Ahn, Haoran Jiang, Arun Jyothidasan, Damini Sood, Chongzhao You, David I. Israel, Alex Shaginian, Qiuxia Chen, Jian Liu, Jialu Wang, Jan Steyaert, Alem W. Kahsai, Andrew P. Landstrom, Robert J. Lefkowitz, Howard A. Rockman

Excessive collagen type VII mediates pleural fibrosis via increasing extracellular matrix stiffness

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Abstract

The interaction between cells and extracellular matrix (ECM) has been recognized in mechanism of fibrotic diseases. Collagen type VII (collagen VII) is an ECM component which plays an important role in cell-ECM interaction, particularly in cell anchoring and maintaining ECM integrity. Pleural mesothelial cells (PMCs) drive inflammatory reactions and ECM production in pleura. However, the role of collagen VII and PMCs in pleural fibrosis was poorly understood. In this study, collagen VII protein was found increase in pleura of patients with tuberculous pleural fibrosis. Investigation of cellular and animal models revealed that collagen VII began to increase at early stage in pleural fibrotic process. Increase of collagen VII occurred ahead of collagen I and α-SMA in PMCs and pleura of animal models. Inhibition of collagen VII by mesothelial cell-specific deletion of collagen VII gene (WT1-Cre+-COL7A1flox/flox) attenuated mouse experimental pleural fibrosis. At last, it was found that excessive collagen VII changed collagen conformation which resulted in elevation of ECM stiffness. Elevation of ECM stiffness activated integrin/PI3K-AKT/JUN signaling and promoted more ECM deposition, as well as mediated pleural fibrosis. In conclusion, excessive collagen VII mediated pleural fibrosis via increasing extracellular matrix stiffness.

Authors

Qian Li, Xin-Liang He, Shuai-Jun Chen, Qian Niu, Tan-Ze Cao, Xiao-Ling Cui, Zi-Heng Jia, He-De Zhang, Xiao Feng, Ye-Han Jiang, Li-Mei Liang, Pei-Pei Cheng, Shi-He Hu, Liang Xiong, Meng Wang, Hong Ye, Wan-Li Ma

Biallelic variants in ARHGAP19 cause a progressive inherited motor-predominant neuropathy

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Abstract

Charcot-Marie-Tooth Disease is a clinically and genetically heterogeneous group of hereditary neuropathies. Despite progress in genetic sequencing, around a quarter of patients remain unsolved. Here, we identify 16 recessive variants in the RhoGTPase activating protein 19 gene (ARHGAP19) causing motor-predominant neuropathy in 25 individuals from 20 unrelated families. The ARHGAP19 protein acts as a negative regulator of the RhoA GTPase. In vitro biochemical and cellular assays revealed that patient variants impair the GTPase-activating protein (GAP) activity of ARHGAP19 and reduce ARHGAP19 protein levels. Combined in vitro and in vivo studies reveal that human ARHGAP19, and conserved ARHGAP19 orthologs in Drosophila and Zebrafish, influence motoneuron morphology and promote locomotor capacity. Transcriptomic studies further demonstrate that ARHGAP19 regulates cellular pathways associated with motor proteins and the cell cycle. Taken together, our findings establish ARHGAP19 variants as a cause of inherited neuropathy acting through a loss-of-function mechanism.

Authors

Natalia Dominik, Stephanie Efthymiou, Christopher J. Record, Xinyu Miao, Renee Q. Lin, Jevin M. Parmar, Annarita Scardamaglia, Reza Maroofian, Simon A. Lowe, Gabriel N. Aughey, Abigail D. Wilson, Riccardo Curro, Ricardo P. Schnekenberg, Shahryar Alavi, Leif Leclaire, Yi He, Kristina Zhelcheska, Yohanns Bellaiche, Isabelle Gaugué, Mariola Skorupinska, Liedewei Van de Vondel, Sahar I. Da'as, Valentina Turchetti, Serdal Güngör, Gavin V. Monahan, Ehsan Ghayoor Karimiani, Yalda Jamshidi, Phillipa J. Lamont, Camila Armirola-Ricaurte, Haluk Topaloglu, Albena Jordanova, Mashaya Zaman, Selina H. Banu, Wilson Marques, Pedro J. Tomaselli, Busra Aynekin, Ali Cansu, Huseyin Per, Ayten Güleç, Javeria Raza Alvi, Tipu Sultan, Arif Khan, Giovanni Zifarelli, Shahnaz Ibrahim, Grazia M. S. Mancini, M.M. Motazacker, Esther Brusse, Vincenzo Lupo, Teresa Sevilla, A. Nazli Başak, Seyma Tekgul, Robin J. Palvadeau, Jonathan Baets, Yesim Parman, Arman Çakar, Rita Horvath, Tobias B. Haack, Jan-Hendrik Stahl, Kathrin Grundmann-Hauser, Joohyun Park, Stephan Zuchner, Nigel G. Laing, Lindsay A. Wilson, Alexander M. Rossor, James Polke, Fernanda Barbosa Figueiredo, André Pessoa, Fernando Kok, Antônio Rodrigues Coimbra-Neto, Marcondes C. Franca Jr, Gianina Ravenscroft, Sherifa A. Hamed, Wendy K. Chung, Alan M. Pittman, Daniel P. Osborn, Michael Hanna, Andrea Cortese, Mary M. Reilly, James E.C. Jepson, Nathalie Lamarche-Vane, Henry Houlden

Stimulated thyroid hormone synthesis machinery drives thyrocyte cell death independent of ER stress

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Abstract

It is now recognized that patients and animal models expressing genetically-encoded misfolded mutant thyroglobulin (TG, the protein precursor for thyroid hormone synthesis) exhibit dramatic swelling of the endoplasmic reticulum (ER) with ER stress and cell death in thyrocytes — seen both in homozygotes (with severe hypothyroidism) and heterozygotes (with subclinical hypothyroidism). The thyrocyte death phenotype is exacerbated upon thyroidal stimulation (by thyrotropin, TSH), as cell death is inhibited upon treatment with exogenous thyroxine. TSH stimulation might contribute to cytotoxicity by promoting ER stress, or by an independent mechanism. Here we’ve engineered knockout mice completely lacking Tg expression. Like other animals/patients with mutant TG, these animals rapidly develop severe goitrous hypothyroidism; however, thyroidal ER stress is exceedingly low — lower even than that seen in wildtype mice. Nevertheless, mice lacking TG exhibit abundant thyroid cell death, which depends upon renegade thyroidal iodination — it is completely suppressed in a genetic model lacking effective iodination, or in Tg-KO mice treated with propylthiouracil (iodination inhibitor), or iodide deficiency. Thyrocytes in culture are killed not in the presence of H2O2 alone, but rather upon peroxidase-mediated iodination, with cell death blocked by propylthiouracil. Thus, in the thyroid gland bearing Tg mutation(s), TSH-stimulated iodination activity triggers thyroid cell death.

Authors

Crystal Young, Xiaohan Zhang, Xiaofan Wang, Aaron P. Kellogg, Kevin Pena, August Z. Cumming, Xiao-Hui Liao, Dennis Larkin, Hao Zhang, Emma Mastroianni, Helmut Grasberger, Samuel Refetoff, Peter Arvan

A PP2A molecular glue overcomes ras/mapk inhibitor resistance in kras-mutant non-small cell lung cancer

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Abstract

The effectiveness of RAS/MAPK inhibitors in treating metastatic KRAS-mutant NSCLC is often hindered by the development of resistance driven by disrupted negative feedback mechanisms led by phosphatases like PP2A. PP2A is frequently suppressed in lung cancer to maintain elevated RAS/MAPK activity. Despite its established role in regulating oncogenic signaling, targeting PP2A with RAS/MAPK to prevent resistance has not been previously demonstrated. In this study, we aimed to establish a treatment paradigm by combining a PP2A molecular glue with a RAS/MAPK inhibitor to restore PP2A activity and counteract resistance. We demonstrated that KRASG12C and MEK1/2 inhibitors disrupted PP2A carboxymethylation and destabilized critical heterotrimeric complexes. Furthermore, genetic disruption of PP2A carboxymethylation enhanced intrinsic resistance to MEK1/2 inhibition both in vitro and in vivo. We developed RPT04402, a PP2A molecular glue that selectively stabilizes PP2A-B56α heterotrimers. In both commercial cell lines and a patient-derived model, combining RPT04402 with a RAS/MAPK inhibitor slowed proliferation and enhanced apoptosis. In mouse xenografts, this combination induced tumor regressions, extended median survival, and delayed the onset of treatment resistance. These findings highlight that promoting PP2A stabilization and RAS/MAPK inhibition presents a promising therapeutic strategy to improve treatment outcomes and overcome resistance in metastatic KRAS-mutant NSCLC.

Authors

Brynne Raines, Stephanie Tseng-Rogenski, Amanda C. Dowdican, Irene Peris, Matthew Hinderman, Kaitlin P. Zawacki, Kelsey Barrie, Gabrielle Hodges Onishi, Alexander M. Dymond, Tahra K. Luther, Sydney Musser, Behirda Karaj Majchrowski, J. Chad Brenner, Aqila Ahmed, Derek J. Taylor, Caitlin M. O'Connor, Goutham Narla

Kidney-specific claudin-2 deficiency leads to medullary nephrocalcinosis in mice

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Abstract

Deposits of hydroxyapatite called Randall's plaques are found in the renal papilla of calcium oxalate kidney stone formers and likely serve as the nidus for stone formation, but their pathogenesis is unknown. Claudin-2 is a paracellular ion channel that mediates calcium reabsorption in the renal proximal tubule. To investigate the role of renal claudin-2, we generated kidney tubule-specific claudin-2 conditional knockout mice (KS-Cldn2 KO). KS-Cldn2 KO mice exhibited transient hypercalciuria in early life. Normalization of urine calcium was accompanied by a compensatory increase in expression and function of renal tubule calcium transporters, including in the thick ascending limb. Despite normocalciuria, KS-Cldn2 KO mice developed papillary hydroxyapatite deposits, beginning at 6 months of age, that resembled Randall's plaques and tubule plugs. Bulk chemical tissue analysis and laser ablation-inductively coupled plasma mass spectrometry revealed a gradient of intrarenal calcium concentration along the corticomedullary axis in normal mice, that was accentuated in KS-Cldn2 KO mice. Our findings provide evidence for the “vas washdown” hypothesis for Randall's plaque formation, and identify the corticomedullary calcium gradient as a target for therapies to prevent kidney stone disease.

Authors

Christine V. Behm, Duuamene Nyimanu, Ony Araujo Galdino, Sadhana Kanoo, Young Chul Kim, Natalia Lopez, Helen Goodluck, Peter S. Rowe, Andrew P. Evan, André J. Sommer, Matthew N. Barr, Tracy Punshon, Volker Vallon, Brian P. Jackson, James C. Williams Jr., Alan S.L. Yu

S100a9 lactylation triggers neutrophil trafficking and cardiac inflammation in myocardial ischemia/reperfusion injury

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Abstract

Lactylation, a post-translational modification derived from glycolysis, plays a pivotal role in ischemic heart diseases. Neutrophils are predominantly glycolytic cells that trigger intensive inflammation of myocardial ischemia reperfusion (MI/R). However, whether lactylation regulates neutrophil function during MI/R remains unknown. Employing lactyl proteomics analysis, S100a9 was lactylated at lysine 26 (S100a9K26la) in neutrophils, with elevated levels observed in both acute myocardial infarction (AMI) patients and MI/R model mice. S100a9K26la was demonstrated driving the development of MI/R using mutant knock-in mice. Mechanistically, lactylated S100a9 translocated to the nucleus of neutrophils, where it binded to the promoters of migration-related genes, thereby enhancing their transcription as a co-activator and promoting neutrophil migration and cardiac recruitment. Additionally, lactylated S100a9 was released during NETosis, leading to cardiomyocyte death by disrupting mitochondrial function. The enzyme dihydrolipoyllysine-residue acetyltransferase (DLAT) was identified as the lactyltransferase facilitating neutrophil S100a9K26la post-MI/R, a process that could be restrained by α-lipoic acid. Consistently, targeting DLAT/S100a9K26la axis suppressed neutrophil burden and improved cardiac function post-MI/R. In patients with AMI, elevated S100a9K26la levels in plasma were positively correlated with cardiac death. These findings highlight S100a9 lactylation as a potential therapeutic target for MI/R and as a promising biomarker for evaluating poor prognosis of MI/R.

Authors

Xiaoqi Wang, Xiangyu Yan, Ge Mang, Yujia Chen, Shuang Liu, Jiayu Sui, Zhonghua Tong, Penghe Wang, Jingxuan Cui, Qiannan Yang, Yafei Zhang, Dongni Wang, Ping Sun, Weijun Song, Zexi Jin, Ming Shi, Peng Zhao, Jia Yang, Mingyang Liu, Naixin Wang, Tao Chen, Yong Ji, Bo Yu, Maomao Zhang

Endoglucanase-2 (Eng2), a shared immunodominant antigen in dimorphic fungi that elicits immunity during infection

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Abstract

Herein, we describe a shared surface and cell wall protein, Endoglucanase 2 (Eng2), expressed on the etiological agents that cause the endemic systemic mycoses of North America – Blastomyces, Coccidioides and Histoplasma. We demonstrate that despite sequence variation of the protein across these related fungi, exposure to Eng2 vaccinates and protects inbred and humanized HLA-DR4 strains of mice against lethal experimental infections with these fungi by eliciting adaptive immunity mediated by CD4 T cells. We also show that CD4 T cell precursors against Eng2 are detectable in naïve individuals and that patients who have recovered from these infections evince a memory and recall CD4 T cell response to Eng2 and its immunodominant epitopes that we have mapped. We create and catalogue new tools and information such as immunodominant peptide epitopes of Eng2 from each fungus recognized by inbred mice and human subjects and we engineer peptide-MHC II tetramers for tracking T cells in inbred and HLA-DR4 humanized mice that will be useful for those who study these infections in mice and humans. Lastly, because most patients demonstrate memory and recall responses against Eng2, our work offers new tools for diagnosis of this collection of infectious diseases across North America.

Authors

Uju J. Okaa, Cleison Ledesma Taira, Lucas dos Santos Dias, Hannah Dobson, Gregory C. Kujoth, Althea Campuzano, E.Jane Homan, George R. Thompson, Chiung-Yu Hung, George S. Deepe, Marcel Wüthrich, Bruce S. Klein

CDKL1 variants affecting ciliary formation predispose to thoracic aortic aneurysm and dissection

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Abstract

Genetic factors are fundamental in the etiology of thoracic aortic aneurysm and dissection (TAAD), but the genetic cause is detected in only about 30% of cases. To define unreported TAAD-associated sequence variants, exome and gene panel sequencing was performed in 323 patients. We identified heterozygous CDKL1 variants [c.427T>C p.(Cys143Arg), c.617C>T p.(Ser206Leu), and c.404C>T p.(Thr135Met)] in 6 patients from 3 families with TAAD-spectrum disorders. CDKL1 encodes a protein kinase involved in ciliary biology. Amino acid substitutions were predicted to affect CDKL1 catalytic activity or protein binding properties. CDKL1 was expressed in vascular smooth muscle cells in normal and diseased human aortic wall tissue. Cdkl1 knockdown and transient knockout in zebrafish resulted in intersomitic vessel (ISV) malformations and aortic dilation. Co-injection of human CDKL1wildtype, but not CDKL1Cys143Arg and CDKL1Ser206Leu RNA, rescued ISV malformations. All variants affected CDKL1 kinase function and profiling data, and altered protein-protein binding properties, particularily with ciliary transport molecules. Expression of CDKL1 variants in heterologeous cells interfered with cilia formation and length, CDKL1 localization, and p38-MAPK and Vegf signaling. Our data suggest a role of CDKL1 variants in the pathogenesis of TAAD-spectrum disorders. The association between primary cilia dysregulation and TAAD expands our knowledge of the underlying molecular pathophysiology.

Authors

Theresa Nauth, Melanie Philipp, Sina Renner, Martin D. Burkhalter, Helke Schüler, Ceren Saygi, Kristian Händler, Bente Siebels, Alice Busch, Thomas Mair, Verena Rickassel, Sophia Deden, Konstantin Hoffer, Jakob Olfe, Thomas S. Mir, Yskert von Kodolitsch, Evaldas Girdauskas, Meike Rybczynski, Malte Kriegs, Hannah Voß, Thomas Sauvigny, Malte Spielmann, Malik Alawi, Susanne Krasemann, Christian Kubisch, Till J. Demal, Georg Rosenberger

The cell-type-specific genetic architecture of chronic pain in brain and dorsal root ganglia

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Abstract

Chronic pain is a complex clinical problem comprising multiple conditions that may share a common genetic profile. Genome-wide association studies (GWAS) have identified many risk loci whose cell-type context remains unclear. Here, we integrated GWAS data on chronic pain (N = 1,235,695) with single-cell RNA sequencing (scRNA-seq) data from human brain and dorsal root ganglia (hDRG), and single-cell chromatin accessibility data from human brain and mouse dorsal horn. Pain-associated variants were enriched in glutamatergic neurons; mainly in prefrontal cortex, hippocampal CA1-3, and amygdala. In hDRG, the hPEP.TRPV1/A1.2 neuronal subtype showed robust enrichment. Chromatin accessibility analyses revealed variant enrichment in excitatory and inhibitory neocortical neurons in brain and in midventral neurons and oligodendrocyte precursor cells in the mouse dorsal horn. Gene-level heritability in the brain highlighted roles for kinase activity, GABAergic synapses, axon guidance, and neuron projection development. In hDRG, implicated genes related to glutamatergic signaling and neuronal projection. In cervical DRG of patients with acute or chronic pain (N = 12), scRNA-seq data from neuronal or non-neuronal cells were enriched for chronic pain-associated genes (e.g., EFNB2, GABBR1, NCAM1, SCN11A). This cell-type-specific genetic architecture of chronic pain across central and peripheral nervous system circuits provides a foundation for targeted translational research.

Authors

Sylvanus Toikumo, Marc Parisien, Michael J. Leone, Chaitanya Srinivasan, Huasheng Yu, Asta Arendt-Tranholm, Úrzula Franco-Enzástiga, Christoph Hofstetter, Michele Curatolo, Wenqin Luo, Andreas R. Pfenning, Rebecca P. Seal, Rachel L. Kember, Theodore J. Price, Luda Diatchenko, Stephen G. Waxman, Henry R. Kranzler

IL-17-producing γδ T cells in the tumor microenvironment promote radioresistance in mice

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Abstract

The immunosuppressive tumor microenvironment (TME) drives radioresistance, but the role of γδ T cells in regulating radiosensitivity remains incompletely understood. In this study, we found that γδ T cell infiltration in the TME substantially increased after radiotherapy and contributed to radioresistance. Depletion of γδ T cells enhanced radiosensitivity. Single-cell RNA sequencing revealed that γδ T cells in the post-radiotherapy TME were characterized by the expression of Zbtb16, Il23r, and Il17a, and served as the primary source of IL-17A. These γδ T cells promoted radioresistance by recruiting myeloid-derived suppressor cells and suppressing T cell activation. Mechanistically, radiotherapy-induced tumor cell-derived microparticles containing dsDNA activated the cGAS-STING/NF-κB signaling pathway in macrophages, upregulating the expression of the chemokine CCL20, which was critical for γδ T cell recruitment. Targeting γδ T cells and IL-17A enhanced radiosensitivity and improved the efficacy of radiotherapy combined with anti-PD-1 immunotherapy, providing potential therapeutic strategies to overcome radioresistance.

Authors

Yue Deng, Xixi Liu, Xiao Yang, Wenwen Wei, Jiacheng Wang, Zheng Yang, Yajie Sun, Yan Hu, Haibo Zhang, Yijun Wang, Zhanjie Zhang, Lu Wen, Fang Huang, Kunyu Yang, Chao Wan

Defective Notch1 signaling in endothelial cells drives pathogenesis in a mouse model of Adams-Oliver Syndrome

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Abstract

Adams-Oliver Syndrome (AOS) is a rare congenital disorder characterized by scalp, limb, and cardiovascular defects. While variants in the NOTCH1 receptor, DLL4 ligand, and RBPJ transcription factor have been implicated in AOS, the driving tissue types and molecular mechanisms by which these variants cause pathogenesis are unknown. Here, we used quantitative binding assays to show that AOS-associated RBPJ missense variants compromise DNA binding but not cofactor binding. These findings suggest that AOS-associated RBPJ variants do not function as loss-of-function alleles but instead act as dominant-negative proteins that sequester cofactors from DNA. Consistent with this idea, mice carrying an AOS-associated Rbpj allele develop dominant phenotypes that include increased lethality and cardiovascular defects in a Notch1 heterozygous background, whereas Notch1 and Rbpj compound heterozygous null alleles are well-tolerated. To facilitate studies into the tissues driving AOS pathogenesis, we employed conditional genetics to isolate the contribution of the vascular endothelium to the development of AOS-like phenotypes. Importantly, our studies show that expression of the Rbpj AOS allele in endothelial cells is both necessary and sufficient to cause lethality and cardiovascular defects. These data establish that reduced Notch1 signaling in the vasculature is a key driver of pathogenesis in this AOS mouse model.

Authors

Alyssa F. Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K. Gagliani, Christopher Ahn, Hee-Woong Lim, Laura Southgate, Rhett A. Kovall, Raphael Kopan, Brian Gebelein

BAF60a-dependent chromatin remodeling preserves β-cell function and contributes to the therapeutic benefits of GLP-1R agonists

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Abstract

Impaired glucose-stimulated insulin secretion (GSIS) is a hallmark of β-cell dysfunction in diabetes. Epigenetic mechanisms govern cellular glucose sensing and GSIS by β-cells, but they remain incompletely defined. Here, we found that BAF60a functions as a chromatin regulator that sustains biphasic GSIS and preserves β-cell function under metabolic stress conditions. BAF60a was downregulated in β-cells from obese and diabetic mice, monkeys, and humans. β-cell-specific inactivation of BAF60a in adult mice impaired GSIS, leading to hyperglycemia and glucose intolerance. Conversely, restoring BAF60a expression improved β-cell function and systemic glucose homeostasis. Mechanistically, BAF60a physically interacted with Nkx6.1 to selectively modulate chromatin accessibility and transcriptional activity of target genes critical for GSIS coupling in islet β-cells. A BAF60a V278M mutation associated with decreased β-cell GSIS function was identified in human subjects. Mice carrying this mutation, which disrupted the interaction between BAF60a and Nkx6.1, displayed β-cell dysfunction and impaired glucose homeostasis. In addition, GLP-1R and GIPR expression was significantly reduced in BAF60a-deficient islets, attenuating the insulinotropic effect of GLP-1R agonists. Together, these findings support a role for BAF60a as a component of the epigenetic machinery that shapes the chromatin landscape in β-cells critical for glucose sensing and insulin secretion.

Authors

Xinyuan Qiu, Ruo-Ran Wang, Qing-Qian Wu, Hongxing Fu, Shuaishuai Zhu, Wei Chen, Wen Wang, Haide Chen, Xiuyu Ji, Wenjing Zhang, Dandan Yan, Jing Yan, Li Jin, Rong Zhang, Mengjie Shi, Ping Luo, Yingqing Yang, Qintao Wang, Ziyin Zhang, Wei Ding, Xiaowen Pan, Chengbin Li, Bin Liang, Guoji Guo, Hai-long Piao, Min Zheng, Yan Sheng, Lingyun Zhu, Cheng Hu, Zhuo-Xian Meng

S-acyl transferase ZDHHC13 modulates tumor microenvironment interactions to suppress metastasis in melanoma models

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Abstract

The intratumor microenvironment shapes the metastatic potential of cancer cells and their susceptibility to any immune response. Yet the nature of the signals within the microenvironment that control anti-cancer immunity and how they are regulated is poorly understood. Here, using melanoma as a model, we investigate the involvement in metastatic dissemination and the immune-modulatory microenvironment of Protein S-Acyl Transferases, as an underexplored class of potential therapeutic targets. We find that ZDHHC13, suppresses metastatic dissemination by palmitoylation of CTNND1, leading to stabilization of E-cadherin. Importantly, ZDHHC13 also reshapes the tumor immune microenvironment by suppressing lysophosphatidylcholine (LPC) synthesis in melanoma cells, leading to inhibition of M2-like tumor-associated macrophages that we show degrades E-cadherin via MMP12 expression. Consequently, ZDHHC13 activity suppresses tumor growth and metastasis in immunocompetent mice. Our study highlights the therapeutic potential of targeting the ZDHHC13-E-cadherin axis and its downstream metabolic and immune-modulatory mechanisms, offering additional strategies to inhibit melanoma progression and metastasis.

Authors

Hongjin Li, Jianke Lyu, Yu Sun, Chengqian Yin, Yuewen Li, Weiqiang Chen, Suan-Sin Foo, Xianfang Wu, Colin Goding, Shuyang Chen

Dysfunctional LHX6 pallido-subthalamic projections mediate epileptic events in a mouse model of Leigh Syndrome

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Abstract

Deficits in the mitochondrial energy-generating machinery cause mitochondrial disease (MD), a group of untreatable and usually fatal disorders. Among many severe symptoms, refractory epileptic events are a common neurological presentation of MD. However, the neuronal substrates and circuits for MD-induced epilepsy remain unclear. Here, using mouse models of Leigh Syndrome, a severe form of MD associated to epilepsy, that lack mitochondrial complex I subunit NDUFS4 in a constitutive or conditional manner, we demonstrate that mitochondrial dysfunction leads to a reduction in the number of GABAergic neurons in the rostral external globus pallidus (GPe), and identify a specific affectation of pallidal Lhx6-expressing inhibitory neurons, contributing to altered GPe excitability. Our findings further reveal that viral vector-mediated Ndufs4 re-expression in the GPe effectively prevents seizures and improves the survival in the models. Additionally, we highlight the subthalamic nucleus (STN) as a critical structure in the neural circuit involved in mitochondrial epilepsy, as its inhibition effectively reduces epileptic events. Thus, we have identified a role for pallido-subthalamic projections in the development of epilepsy in the context of mitochondrial dysfunction. Our results suggest STN inhibition as a potential therapeutic intervention for refractory epilepsy in patients with MD providing promising leads in the quest to identify effective treatments.

Authors

Laura Sánchez-Benito, Melania González-Torres, Irene Fernández-González, Laura Cutando, María Royo, Joan Compte, Miquel Vila, Sandra Jurado, Elisenda Sanz, Albert Quintana

Distinct colitis-associated macrophages drive NOD2-dependent bacterial sensing and gut homeostasis

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Abstract

Single-cell studies have revealed that intestinal macrophages maintain gut homeostasis through the balanced actions of reactive (inflammatory) and tolerant (non-inflammatory) subpopulations. How such balance is impaired in inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), remains unresolved. Here, we define colon-specific macrophage states and reveal the critical role of non-inflammatory colon-associated macrophages (niColAMs) in IBD recovery. Through trans-scale analyses—integrating computational transcriptomics, proteomics, and in vivo interventional studies—we identified GIV (CCDC88A) as a key regulator of niColAMs. GIV emerged as the top-ranked gene in niColAMs that physically and functionally interacts with NOD2, an innate immune sensor implicated in CD and UC. Myeloid-specific GIV depletion exacerbates infectious colitis, prolongs disease, and abolishes the protective effects of the NOD2 ligand, muramyl dipeptide, in colitis and sepsis models. Mechanistically, GIV’s C-terminus binds the terminal leucine-rich repeat (LRR#10) of NOD2 and is required for NOD2 to dampen inflammation and clear microbes. The CD-associated 1007fs NOD2-variant, which lacks LRR#10, cannot bind GIV—providing critical insights into how this clinically relevant variant impairs microbial sensing and clearance. These findings illuminate a critical GIV-NOD2 axis essential for gut homeostasis and highlight its disruption as a driver of dysbiosis and inflammation in IBD.

Authors

Gajanan D. Katkar, Mahitha Shree Anandachar, Stella-Rita C. Ibeawuchi, Ella G. McLaren, Megan L. Estanol, Kennith Carpio-Perkins, Shu-Ting Hsu, Celia R. Espinoza, Jane E. Coates, Yashaswat S. Malhotra, Madhubanti Mullick, Vanessa Castillo, Daniella Vo, Saptarshi Sinha, Pradipta Ghosh

Androgen deprivation-mediated activation of AKT is enhanced in prostate cancer with TMPRSS2:ERG fusion

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Abstract

TMPRSS2:ERG gene fusion (T:E fusion) in prostate adenocarcinoma (PCa) puts ERG under androgen receptor (AR) regulated TMPRSS2 expression. T:E fusion is associated with PTEN loss, and is highly associated with decreased INPP4B expression, which together may compensate for ERG-mediated suppression of AKT signaling. We confirmed in PCa cells and a mouse PCa model that ERG suppresses IRS2 and AKT activation. In contrast, ERG downregulation did not increase INPP4B, suggesting its decrease is indirect and reflects selective pressure to suppress INPP4B function. Notably, INPP4B expression is decreased in PTEN-intact and PTEN-deficient T:E fusion tumors, suggesting selection for a nonredundant function. As ERG in T:E fusion tumors is AR regulated, we further assessed whether AR inhibition increases AKT activity in T:E fusion tumors. A T:E fusion positive PDX had increased AKT activity in vivo and response to AKT inhibition in vitro after androgen deprivation. Moreover, two clinical trials of neoadjuvant AR inhibition prior to radical prostatectomy showed greater increases in AKT activation in the T:E fusion positive versus negative tumors. These findings indicate that AKT activation may mitigate the efficacy of AR targeted therapy in T:E fusion PCa, and that these patients may most benefit from combination therapy targeting AR and AKT.

Authors

Fen Ma, Sen Chen, Luigi Cecchi, Betul Ersoy-Fazlioglu, Joshua W. Russo, Seiji Arai, Seifeldin Awad, Carla Calagua, Fang Xie, Larysa Poluben, Olga Voznesensky, Anson T. Ku, Fatima Karzai, Changmeng Cai, David J. Einstein, Huihui Ye, Xin Yuan, Alex Toker, Mary-Ellen Taplin, Adam G. Sowalsky, Steven P. Balk

Aryl hydrocarbon receptor restrains tonic cytokine responses by inhibiting microbiota sensing in monocytes

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Abstract

Immune cells are constantly exposed to microbiota-derived compounds that can engage innate recognition receptors. How this constitutive stimulation is down-modulated to avoid systemic inflammation and auto-immunity is poorly understood. Here we show that Aryl hydrocarbon Receptor (AhR) deficiency in monocytes unleashes spontaneous cytokine responses in vivo, driven by STING-mediated tonic sensing of microbiota. This effect was specific to monocytes, as mice deficient for AhR specifically in macrophages did not show any dysregulation of tonic cytokine responses. AhR inhibition also increased tonic cytokine production in human monocytes. Finally, in patients with systemic juvenile idiopathic arthritis, low AhR activity in monocytes correlated with elevated cytokine responses. Our findings evidence an essential role for AhR in monocytes in restraining tonic microbiota sensing and in maintaining immune homeostasis.

Authors

Adeline Cros, Alessandra Rigamonti, Alba de Juan, Alice Coillard, Mathilde Rieux-Laucat, Darawan Tabtim-On, Emeline Papillon, Christel Goudot, Alma-Martina Cepika, Romain Banchereau, Virginia Pascual, Marianne Burbage, Burkhard Becher, Elodie Segura

ER stress upregulates S100A11 in steatohepatitis models via epigenetic modifications within the lipotoxicity influenced enhancer

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Abstract

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease characterized by complex interactions between lipotoxicity, ER stress responses, and immune-mediated inflammation. We identified enrichment of the proinflammatory alarmin S100 calcium-binding protein A11 (S100A11) on extracellular vesicles stimulated by palmitate-induced lipotoxic ER stress with concomitant upregulation of hepatocellular S100A11 abundance in an IRE1A-XBP1s dependent manner. We next investigated the epigenetic mechanisms that regulate this stress response. Publicly available human liver ChIP-Seq GEO datasets demonstrated a region of histone H3 lysine 27 (H3K27) acetylation upstream to the S100A11 promoter. H3K27acetylation ChIP-qPCR demonstrated a positive correlation between lipotoxic ER stress and H3K27acetylation of the region, which we termed Lipotoxicity Influenced Enhancer (LIE) domain. CRISPR-mediated repression of the LIE domain reduced palmitate-induced H3K27acetylation and corresponding S100A11 upregulation in Huh7 cells and immortalized mouse hepatocytes. Silencing of the murine LIE in two independent steatohepatitis models demonstrated reduced S100a11 upregulation and attenuated liver injury. We confirmed H3K27acetylation and XBP1s occupancy at the LIE domain in human MASH liver samples and an increase in hepatocyte-derived S100A11-enriched extracellular vesicles in MASH patient plasma. Our studies demonstrate a LIE domain which mediates hepatic S100A11 upregulation. This pathway may be a potential therapeutic target in MASH.

Authors

P. Vineeth Daniel, Hanna L. Erickson, Daheui Choi, Feda H. Hamdan, Yasuhiko Nakao, Gyanendra Puri, Takahito Nishihara, Yeriel Yoon, Amy S. Mauer, Debanjali Dasgupta, Jill Thompson, Alexander Revzin, Harmeet Malhi