Disrupting Integrator complex subunit INTS6 causes neurodevelopmental disorders and impairs neurogenesis and synapse development

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Abstract

The Integrator complex plays essential roles in RNA polymerase II transcription termination and RNA processing. Here, we identify INTS6, a subunit of the Integrator complex, as a novel gene associated with neurodevelopmental disorders (NDDs). Through analysis of large NDD cohorts and international collaborations, we identified 23 families harboring monoallelic likely gene-disruptive or de novo missense variants in INTS6. Phenotypic characterization revealed shared features, including language and motor delays, autism, intellectual disability, and sleep disturbances. Using a nervous-system conditional knockout (cKO) mouse model, we show that Ints6 deficiency disrupts early neurogenesis, cortical lamination, and synaptic development. Ints6 cKO mice displayed a thickened ventricular zone/subventricular zone, thinning of the cortical plate, reduced neuronal differentiation, and increased apoptosis in cortical layer 6. Behavioral assessments of heterozygous mice revealed deficits in social novelty preference, spatial memory, and hyperactivity, mirroring phenotypes observed in individuals with INTS6 variants. Molecular analyses further revealed that INTS6 deficiency alters RNA polymerase II dynamics, disrupts transcriptional regulation, and impairs synaptic gene expression. Treatment with a CDK9 inhibitor (CDK9i) reduced RNAPII phosphorylation, thereby limiting its binding to target genes. Notably, CDK9i reversed neurosphere over-proliferation and rescued the abnormal dendritic spine phenotype caused by Ints6 deficiency. This work advances understanding of INTS-related NDD pathogenesis and highlights potential therapeutic targets for intervention.

Authors

Xiaoxia Peng, Xiangbin Jia, Hanying Wang, Jingjing Chen, Xiaolei Zhang, Senwei Tan, Xinyu Duan, Can Qiu, Mengyuan Hu, Haiyan Hou, Ilaria Parenti, Alma Kuechler, Frank J. Kaiser, Alicia Renck, Raymond Caylor, Cindy Skinner, Joseph Peeden, Benjamin Cogne, Bertrand Isidor, Sandra Mercier, Gael Nicolas, Anne-Marie Guerrot, Flavio Faletra, Luciana Musante, Lior Cohen, Gaber Bergant, Goran Čuturilo, Borut Peterlin, Andrea Seeley, Kristine Bachman, Julian A. Martinez-Agosto, Conny van Ravenswaaij-Arts, Dennis Bos, Katherine H. Kim, Tobias Bartolomaeus, Zelia Schmederer, Rami Abou Jamra, Erfan Aref-Eshghi, Wenjing Zhao, Yongyi Zou, Zhengmao Hu, Qian Pan, Faxiang Li, Guodong Chen, Jiada Li, Zhangxue Hu, Kun Xia, Jieqiong Tan, Hui Guo

PTBP1 variants displaying altered nucleocytoplasmic distribution are responsible for a neurodevelopmental disorder with skeletal dysplasia

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Abstract

Polypyrimidine tract-binding protein PTBP1 is a heterogeneous nuclear ribonucleoprotein primarily known for its alternative splicing activity. It shuttles between the nucleus and cytoplasm via partially overlapping N-terminal nuclear localization (NLS) and export (NES) signals. Despite its fundamental role in cell growth and differentiation, its involvement in human disease remains poorly understood. We identified 27 individuals from 25 families harboring de novo or inherited pathogenic variants — predominantly start-loss (89%) and, to a lesser extent, missense (11%) — affecting NES/NLS motifs. Affected individual presented with a syndromic neurodevelopmental disorder and variable skeletal dysplasia with disproportionate short-limbed short stature. Intellectual functioning ranged from normal to moderately delayed. Start-loss variants led to translation initiation from an alternative downstream in-frame methionine, resulting in loss of the NES and the first half of the bipartite NLS, and increased cytoplasmic stability. Start-loss and missense variants shared a DNA methylation episignature in peripheral blood and altered nucleocytoplasmic distribution in vitro and in vivo with preferential accumulation in processing bodies, causing aberrant gene expression but normal RNA splicing. Transcriptomic analysis of patient-derived fibroblasts revealed dysregulated pathways involved in osteochondrogenesis and neurodevelopment. Overall, our findings highlight a cytoplasmic role for PTBP1 in RNA stability and disease pathogenesis.

Authors

Aymeric Masson, Julien Paccaud, Martina Orefice, Estelle Colin, Outi Mäkitie, Valérie Cormier-Daire, Raissa Relator, Sourav Ghosh, Jean-Marc Strub, Christine Schaeffer-Reiss, Carlo Marcelis, David A. Koolen, Rolph Pfundt, Elke de Boer, Lisenka E.L.M. Vissers, Thatjana Gardeitchik, Lonneke A.M. Aarts, Tuula Rinne, Paulien A. Terhal, Nienke E. Verbeek, Linda C. Zuurbier, Astrid S. Plomp, Marja W. Wessels, Stella A. de Man, Arjan Bouman, Lynne M. Bird, Reem Saadeh-Haddad, Maria J. Guillen Sacoto, Richard Person, Catherine Gooch, Anna C.E. Hurst, Michelle L. Thompson, Susan M. Hiatt, Rebecca O. Littlejohn, Elizabeth R. Roeder, Mari Mori, Scott Hickey, Jesse M. Hunter, Kristy Lee, Khaled Osman, Rana Halloun, Ruxandra Bachmann-Gagescu, Anita Rauch, Dagmar Wieczorek, Konrad Platzer, Johannes Luppe, Laurence Duplomb-Jego, Fatima El It, Yannis Duffourd, Frédéric Tran Mau-Them, Celine Huber, Christopher T. Gordon, Fulya Taylan, Riikka E. Mäkitie, Alice Costantini, Helena Valta, Stephen Robertson, Gemma Poke, Michel Francoise, Andrea Ciolfi, Marco Tartaglia, Nina Ekhilevitch, Rinat Zaid, Michael A. Levy, Jennifer Kerkhof, Haley McConkey, Julian Delanne, Martin Chevarin, Valentin Vautrot, Valentin Bourgeois, Sylvie Nguyen, Nathalie Marle, Patrick Callier, Hana Safraou, Angela Morgan, David J. Amor, Michael Hildebrand, David Coman, Marion Aubert Mucca, Julien Thevenon, Fanny Laffargue, Frédéric Bilan, Céline Pebrel-Richard, Grace Yoon, Michelle M. Axford, Luis A. Pérez-Jurado, Marta Sevilla-Porras, Douglas Black, Christophe Philippe, Bekim Sadikovic, Christel Thauvin-Robinet, Laurence Olivier-Faivre, Michela Ori, Quentin Thomas, Antonio Vitobello

Antithrombin-binding heparan sulfate is ubiquitously expressed in epithelial cells and suppresses pancreatic tumorigenesis

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Abstract

3-O-sulfation of heparan sulfate (HS) is the key determinant for binding and activation of Antithrombin III (AT). This interaction is the basis of heparin treatment to prevent thrombotic events and excess coagulation. Antithrombin-binding HS (HSAT) is expressed in human tissues, but is thought to be expressed in the subendothelial space, mast cells, and follicular fluid. Here we show that HSAT is ubiquitously expressed in the basement membranes of epithelial cells in multiple tissues. In the pancreas, HSAT is expressed by healthy ductal cells and its expression is increased in premalignant pancreatic intraepithelial neoplasia lesions (PanINs), but not in pancreatic ductal adenocarcinoma (PDAC). Inactivation of HS3ST1, a key enzyme in HSAT synthesis, in PDAC cells eliminated HSAT expression, induced an inflammatory phenotype, suppressed markers of apoptosis, and increased metastasis in an experimental mouse PDAC model. HSAT-positive PDAC cells bind AT, which inhibits the generation of active thrombin by tissue factor (TF) and Factor VIIa. Furthermore, plasma from PDAC patients showed accumulation of HSAT suggesting its potential as a marker of tumor formation. These findings suggest that HSAT exerts a tumor suppressing function through recruitment of AT and that the decrease in HSAT during progression of pancreatic tumorigenesis increases inflammation and metastatic potential.

Authors

Thomas Mandel Clausen, Ryan J. Weiss, Jacob R. Tremblay, Benjamin P. Kellman, Joanna Coker, Leo A. Dworkin, Jessica P. Rodriguez, Ivy M. Chang, Timothy Chen, Vikram Padala, Richard Karlsson, Hyemin Song, Kristina L. Peck, Satoshi Ogawa, Daniel R. Sandoval, Hiren J. Joshi, Gaowei Wang, L. Paige Ferguson, Nikita Bhalerao, Allison Moores, Tannishtha Reya, Maike Sander, Thomas C. Caffrey, Jean L. Grem, Alexandra Aicher, Christopher Heeschen, Dzung Le, Nathan E. Lewis, Michael A. Hollingsworth, Paul M. Grandgenett, Susan L. Bellis, Rebecca L. Miller, Mark M. Fuster, David W. Dawson, Dannielle D. Engle, Jeffrey D. Esko

Endothelial STING and STAT1 mediate interferon-independent effects of IL-6 in an endotoxemia-induced model of shock

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Abstract

Severe systemic inflammatory reactions, including sepsis, often lead to shock, organ failure and death, in part through an acute release of cytokines that promote vascular dysfunction. However, little is known about the vascular endothelial signaling pathways regulating the transcriptional profile in failing organs. This work focuses on signaling downstream of IL-6, due to its clinical importance as a biomarker for disease severity and predictor of mortality. Here, we show that loss of endothelial expression of the IL-6 pathway inhibitor, SOCS3, promoted a type I interferon (IFNI)-like gene signature in response to endotoxemia in mouse kidneys and brains. In cultured primary human endothelial cells, IL-6 induced a transient IFNI-like gene expression in a non-canonical, interferon-independent fashion. We further show that STAT3, which we had previously shown to control IL-6-driven endothelial barrier function, was dispensable for this activity. Instead, IL-6 promoted a transient increase in cytosolic mitochondrial DNA and required STAT1, cGAS, STING, and the IRFs 1, 3, and 4. Inhibition of this pathway in endothelial-specific STING knockout mice or global STAT1 knockout mice led to reduced severity of an acute endotoxemic challenge and prevented the endotoxin-induced IFNI-like gene signature. These results suggest that permeability and DNA sensing responses are driven by parallel pathways downstream of this cytokine, provide new insights into the complex response to acute inflammatory responses, and offer the possibility of potential novel therapeutic strategies for independently controlling the intracellular responses to IL-6 in order to tailor the inflammatory response.

Authors

Nina Martino, Erin K. Sanders, Ramon Bossardi Ramos, Iria Di John Portela, Fatma Awadalla, Shuhan Lu, Dareen Chuy, Neil Poddar, Mei Xing G Zuo, Uma Balasubramanian, Peter A. Vincent, Pilar Alcaide, Alejandro P. Adam

Maintenance DNA methylation is required for induced Treg reparative function following viral pneumonia in mice

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Abstract

FOXP3+ natural regulatory T cells (nTregs) promote resolution of inflammation and repair of epithelial damage following viral pneumonia-induced lung injury, thus representing a cellular therapy for patients with severe viral pneumonia and the acute respiratory distress syndrome (ARDS). Whether in vitro induced Tregs (iTregs), which can be rapidly generated in substantial numbers from conventional T cells, also promote lung recovery is unknown. nTregs require specific DNA methylation patterns maintained by the epigenetic regulator, ubiquitin-like with PHD and RING finger domains 1 (UHRF1). Here, we tested whether iTregs promote recovery following viral pneumonia and whether iTregs require UHRF1 for their pro-recovery function. We found that adoptive transfer of iTregs to mice with influenza virus pneumonia promotes lung recovery and that loss of UHRF1-mediated maintenance DNA methylation in iTregs leads to reduced engraftment and a delayed repair response. Transcriptional and DNA methylation profiling of adoptively transferred UHRF1-deficient iTregs that had trafficked to influenza-injured lungs demonstrated transcriptional instability with gain of effector T cell lineage-defining transcription factors. Strategies to promote the stability of iTregs could be leveraged to further augment their pro-recovery function during viral pneumonia and other causes of severe lung injury.

Authors

Anthony M. Joudi, Jonathan K Gurkan, Qianli Liu, Elizabeth M. Steinert, Manuel A. Torres Acosta, Kathryn A. Helmin, Luisa Morales-Nebreda, Nurbek Mambetsariev, Carla Patricia Reyes Flores, Hiam Abdala-Valencia, Samuel E. Weinberg, Benjamin D. Singer

Fatty acid transport protein-2 inhibition enhances glucose tolerance through α-cell-mediated GLP-1 secretion

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Abstract

Type 2 diabetes affects more than 38 million people in the US, and a major complication is kidney disease. During the analysis of lipotoxicity in diabetic kidney disease, global fatty acid transport protein-2 (FATP2) gene deletion was noted to markedly reduce plasma glucose in db/db mice due to sustained insulin secretion. To identify the mechanism, we observed that islet FATP2 expression was restricted to α-cells, and α-cell FATP2 was functional. Basal glucagon and alanine-stimulated gluconeogenesis were reduced in FATP2KO db/db compared to db/db mice. Direct evidence of FATP2KO-induced α-cell-mediated glucagon-like peptide-1 (GLP-1) secretion included increased GLP-1-positive α-cell mass in FATP2KO db/db mice, small molecule FATP2 inhibitor enhancement of GLP-1 secretion in αTC1-6 cells and human islets, and exendin[9-39]-inhibitable insulin secretion in FATP2 inhibitor-treated human islets. FATP2-dependent enteroendocrine GLP-1 secretion was excluded by demonstration of similar glucose tolerance and plasma GLP-1 concentrations in db/db FATP2KO mice following oral versus intraperitoneal glucose loading, non-overlapping FATP2 and preproglucagon mRNA expression, and lack of FATP2/GLP-1 co-immunolocalization in intestine. We conclude that FATP2 deletion or inhibition exerts glucose-lowering effects through α-cell-mediated GLP-1 secretion and paracrine ß-cell insulin release.

Authors

Shenaz Khan, Robert J. Gaivin, Zhiyu Liu, Vincent Li, Ivy Samuels, Jinsook Son, Patrick Osei-Owusu, Jeffrey L. Garvin, Domenico Accili, Jeffrey R. Schelling

Open-label phase 4 trial evaluating nusinersen after onasemnogene abeparvovec in children with spinal muscular atrophy

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Abstract

BACKGROUND. Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disease caused by deletions or mutations of the survival motor neuron 1 gene. Despite the availability of genetically-based treatments for SMA, functional impairments and weakness persist in treated symptomatic individuals. This study addresses whether additional treatment after gene transfer therapy could provide further clinical benefits. METHODS. Interim Day 302 findings are described from the phase 4 open-label RESPOND trial evaluating nusinersen in participants aged ≤ 36 months who had suboptimal clinical status following onasemnogene abeparvovec (OA) treatment, as determined by the investigator. RESULTS. Thirty-seven participants included in the interim analysis were symptomatic at the time of OA administration. Most (92%) had two survival motor neuron 2 gene copies. Age at first nusinersen dose (median [range]) was 9.1 (3–33) months for participants with two SMN2 copies and 34.2 (31–36) months for those with three SMN2 copies, while time from OA dose to first nusinersen dose (median [range]) was 6.3 (3–31) and 13.3 (10–22) months, respectively. Participants had elevated neurofilament light chain (NfL) levels and low compound muscle action potential (CMAP) amplitudes at baseline, suggesting active neurodegeneration and severe denervation at study entry. Improvements from baseline were observed across a range of outcomes at Day 302, including motor function outcomes (HINE-2 and CHOP-INTEND total score), achievement of independent sitting, NfL levels, CMAP, and investigator- and caregiver-reported outcomes. Mean NfL levels decreased rapidly from baseline to Day 183 and remained low at Day 302. Mean ulnar and peroneal CMAP amplitudes increased. No safety concerns were identified. CONCLUSION. Improvements in clinical and biomarker outcomes support the benefit of nusinersen treatment in infants and children with suboptimal clinical status following OA. TRIAL REGISTRATION. ClinicalTrials.gov ID, NCT04488133; EudraCT number, 2020-003492-18. FUNDING. This study was sponsored by Biogen (Cambridge, MA, USA).

Authors

Crystal M. Proud, Richard S. Finkel, Julie A. Parsons, Riccardo Masson, John F. Brandsema, Nancy L. Kuntz, Richard Foster, Wenjing Li, Ross Littauer, Jihee Sohn, Stephanie Fradette, Bora Youn, Angela D. Paradis

A liver-infiltrating CD4⁺ Tfh1 cell response predicts HCV control, hepatitis, and seroconversion during acute infection

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Abstract

Sustained CD4+ T cell immunity is required for resolution of acute hepatitis C virus (HCV) infection but the response remains poorly characterized. Here, circulating CD4+ T cells with high PD-1 and ICOS co-expression were temporally associated with onset of virus control, seroconversion, and hepatitis in HCV-infected chimpanzees. Co-production of Tfh (IL-21, CXCL13) and Th1 (IFN-γ, TNF) cytokines after stimulation with HCV non-structural proteins demonstrated that the response was predominately Tfh1-like and virus-specific. Transcriptional analysis confirmed a Tfh1 lineage assignment. Effector-related genes such as ADGRG1 (GPR56), ZNF683 (Hobit), and KLRB1 (CD161) were also expressed. HCV-specific PD-1hiICOShi CD4+ Tfh1-like cells were enriched in liver, suggesting the potential for B and CD8+ T cell help at the site of virus replication. Most circulating and intrahepatic PD-1hiICOShi CD4+ Tfh1-like cells did not express CXCR5, and therefore resembled CXCR5-negative CXCL13-positive peripheral helper (Tph) cells that infiltrate tumors and tissues inflamed by autoimmunity. PD-1hiICOShi CD4+ cells also peaked after hepatitis A virus infection, but the response was accelerated by several weeks when compared with HCV infection. The PD-1hiICOShi phenotype, and temporal association between the peak response and ALT, may provide markers to guide human studies of CD4+ T cell immunity against HCV and other hepatotropic viruses.

Authors

Heather Blasczyk, William G. Bremer, Christopher C. Phelps, Yan Zhou, David G. Bowen, Zhaohui Xu, Robert E. Lanford, Naglaa H. Shoukry, Arash Grakoui, Nicole E. Skinner, Christopher M. Walker

Multiomic assessments of LNCaP and derived cell strains reveal determinants of prostate cancer pathobiology

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Abstract

A cornerstone of research to improve cancer outcomes involves studies of model systems to identify causal drivers of oncogenesis, understand mechanisms leading to metastases, and develop new therapeutics. While most cancer types are represented by large cell line panels that reflect diverse neoplastic genotypes and phenotypes found in patients, prostate cancer is notable for a very limited repertoire of models that recapitulate the pathobiology of human disease. Of these, Lymph node carcinoma of the prostate (LNCaP) has served as the major resource for basic and translational studies. Here, we delineated the molecular composition of LNCaP and multiple substrains through analyses of whole genome sequences, transcriptomes, chromatin structure, AR cistromes, and functional studies. Our results determined that LNCaP exhibits substantial subclonal diversity, ongoing genomic instability and phenotype plasticity. While several oncogenic features were consistently present across strains, others were unexpectedly variable such as ETV1 expression, Y chromosome loss, a reliance on WNT and glucocorticoid receptor activity, and distinct AR alterations maintaining AR pathway activation. These results document the inherent molecular heterogeneity and ongoing genomic instability that drive diverse prostate cancer phenotypes and provide a foundation for the accurate interpretation and reproduction of research findings.

Authors

Arnab Bose, Armand Bankhead III, Ilsa Coleman, Thomas Persse, Wanting Han, Patricia Galipeau, Brian Hanratty, Tony Chu, Jared Lucas, Dapei Li, Rabeya Bilkis, Pushpa Itagi, Sajida Hassan, Mallory Beightol, Minjeong Ko, Ruth Dumpit, Michael Haffner, Colin Pritchard, Gavin Ha, Peter S. Nelson

TIE2 activation by antibody-clustered endogenous angiopoietin-2 prevents capillary loss and fibrosis in experimental kidney disease

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Abstract

The role of endothelial dysfunction in tubulointerstitial fibrosis associated with chronic kidney disease (CKD) is not well understood. In this study, we demonstrate that the activation of the endothelial tyrosine kinase TIE2 alleviates renal pathology in experimental CKD in mice. TIE2 activation was achieved using a human angiopoietin-2 (ANGPT2)-binding and TIE2-activating antibody (ABTAA), or through adult-induced endothelial-specific knockout of the vascular endothelial protein tyrosine phosphatase gene (Veptp). Both methods significantly protected CKD mice from endothelial dysfunction, peritubular capillary loss, tubular epithelial injury, and tubulointerstitial fibrosis. Conversely, silencing TIE2 through adult-induced endothelial-specific knockout of the Tie2 gene exacerbated CKD pathology. Additionally, we found that endothelial dysfunction promotes renal fibrosis not through endothelial-to-mesenchymal transition as previously expected, but by inducing the expression of pro-fibrotic PDGFB in tubular epithelial cells, a process that is inhibited by TIE2 activation. Our findings suggest that TIE2 activation via ABTAA warrants investigation as a therapy in human CKD, where there is a substantial unmet medical need.

Authors

Riikka Pietilä, Amanda M. Marks-Hultström, Liqun He, Sami Nanavazadeh, Susan E. Quaggin, Christer Betsholtz, Marie Jeansson