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Abstract
Gene therapy-based biological pacemakers have been proposed as an alternative to their hardware-based counterparts. In this context, short-term ectopic expression of the T-box transcription factor 18 (TBX18) in the ventricle has been reported to generate potent short-term pacemaker function in various animal models. Here, we investigated the impact of adeno-associated virus (AAV)-mediated long-term expression of TBX18, and compared the outcomes to those of the pacemaker ion channel Hcn2. Our findings revealed that CMV-driven ectopic TBX18 expression in mouse hearts led to severe cardiac fibrosis. At lower, non-fibrogenic levels, TBX18 maintained its transcriptional function but failed to induce pacemaker phenotypes. TBX18-expressing cells showed suppressed expression of key working myocardial genes, but the pacemaker gene program was not induced. Electrophysiological studies showed abnormal automaticity in TBX18-expressing cells, combined with prolonged repolarization and various current changes. However, no hyperpolarization-activated funny current was detected. In a complete AV-block rat model, AAV-mediated Hcn2 expression induced robust ectopic pacemaker activity in the presence of isoproterenol, whereas TBX18 expression neither generated such activity nor augmented Hcn2-mediated pacing. In conclusion, at functionally non-fibrogenic levels, TBX18 is neither sufficient nor necessary to induce pacemaker activity. In contrast, Hcn2 generates reliable pacing, making it a more viable candidate for biological pacemaker development.
Authors
Jianan Wang, Mathilde R. Rivaud, Mischa Klerk, Arie R. Boender, Ruud N. Visser, Rinske Sparrius, Hee Young Lee, Karel van Duijvenboden, Huiling Zhou, Yuting Yang, Emiel J.M. Kramer, Kyung Ho Park, Larry C. Park, Silke Schrödel, Christian Thirion, Eric Ehrke-Schulz, Anja Ehrhardt, Osne F. Kirzner, Klaus Neef, Hanno L. Tan, Arie O. Verkerk, Vincent M. Christoffels, Gerard J.J. Boink
Abstract
De novo heterozygous variants in CELF2 have recently been associated with a rare neurodevelopmental disorder, yet the mechanisms linking specific variants to distinct clinical phenotypes remain poorly understood. Here, we reported a cohort of 18 individuals and provided evidence that variants causing CELF2 mislocalization, but not protein-null variants, were associated with seizures. Using proband-derived human cortical neurons and transgenic mouse models, we demonstrated that CELF2 underwent activity-dependent nucleocytoplasmic shuttling in excitatory neurons and that its cytoplasmic retention caused neuronal hyperactivity, elevated seizure susceptibility, and learning and memory deficits. We further found that cytoplasmic CELF2 regulated mRNAs critical for synaptic function and neuronal excitability and implicated in epileptic seizures and intellectual disability. Drug screening further identified AKT signaling as a key regulator of CELF2 nucleocytoplasmic shuttling and a candidate target for reversing neuronal hyperactivity. Together, our findings expand the clinical and genetic spectrum of CELF2-related neurodevelopmental disorders and establish a variant-specific mechanism that links CELF2 mislocalization to neuronal hyperactivity, seizures, and cognitive impairment.
Authors
Michelle Hua, Mohamad-Reza Aghanoori, Melissa J. MacPherson, Yi Ren, Shehani V. Siripala, Yifan Yang, Yvonne Yan Yan Or, Malea Nguyen, Robert Duba-Kiss, Daniel Feng, Laura Williams, Christopher J. Gafuik, GengYi Wang, Chloe Quelin, Boris Keren, Sarah Schuhmann, Georgia Vasileiou, Alexia Bourgois, Antonio Vitobello, Christophe Philippe, Zornitza Stark, Richard J. Leventer, George McGillivray, Frederic Tran Mau-Them, Marine Tessarech, Clément Prouteau, Phillis Lakeman, Mahdi M. Motazacker, Donald R. Latner, Raymond C. Caylor, Yvette van Ierland, Eloise Prijoles, Angie Lichty, Evangelos Theodorou, David A. Sweetser, Edward Steel, Jan Cobben, Majed J. Dasouki, Daniel G. Calame, Bertrand Isidor, Benjamin Cogné, Mitchell Kesler, Brooke Rackel, Isabel Clark, Deborah M. Kurrasch, G. Campbell Teskey, James Ellis, Guiqiong He, Scott D. Ryan, Douglas J. Mahoney, A. Micheil Innes, Jonathan R. Epp, Guang Yang
Abstract
Chromatin remodeling is a dynamic epigenetic process that alters chromatin structure to gauge gene accessibility, enabling precise spatiotemporal gene expression, with disruptions often underlying neurodevelopmental disorders (NDDs), although the mechanistic underpinning remains incompletely understood. Despite essential roles in chromatin remodeling processes such as DNA methylation, and histone acetylation and deposition, DMAP1 has not been implicated in human disease. We identified 20 individuals from 16 families with a syndromic NDD carrying homozygous or compound heterozygous variants in DMAP1. Neural-specific knockdown of its Drosophila ortholog, dDMAP1, caused pupal lethality, structural defects in the mushroom body (MB), decreased dendrite length, abnormal social behavior and mechanical-induced seizures. Human reference DMAP1 could largely compensate for the loss of dDMAP1 in knockdown flies, whereas patient variants failed to restore or differentially rescued the phenotypes, confirming their pathogenicity with differing severity. Transcriptome profiling of dDMAP1 knockdown fly brains nominated Cbl and SF1 as downstream targets. Their overexpression rescued the aforementioned lethality and MB defects. Finally, a DNA methylation episignature was identified, leading to the molecular diagnosis of an additional patient. Our findings demonstrate that biallelic inactivating variants in DMAP1 cause a syndromic NDD, expanding the short list of recessive disease-causing genes within the epigenetic machinery.
Authors
Qin Wang, Andrew K. Sobering, Christian Tirrito, Sadegheh Haghshenas, Tina Duelund Hjortshøj, Konrad Platzer, Silke Redler, Michael E. March, Leticia S. Matsuoka, Hang Xi, Josiah Zoodsma, Yuanhua Chen, Mari Mori, Marco L. Leung, Nathalie Couque, Alain Verloes, Antoine Pouzet, Noor A.A. Giesbertz, Marleen E.H. Simon, Ashley K. Yearwood, Dominique L. Assing, Tzung-Chien Hsieh, Jing-Mei Li, Michael A. Levy, Jennifer Kerkhof, Haley McConkey, Jessica Rzasa, Carolyn Lauzon-Young, Raashda A. Sulaiman, Firdous Abdulwahab, Hanan E. Shamseldin, Naif A.M. Almontashiri, Manal Afqi, Vettaikorumakankav Vedanarayanan, Maria J. Guillen Sacoto, Ingrid M. Wentzensen, Nadirah S. Damseh, Rivka Birnbaum, Babeth van Ommeren, Saskia M.J. Hopman, Maha S. Zaki, Gehad Elmakkawy, Erum Afzal, JiHye Kim, Stephanie Efthymiou, Henry Houlden, Ambreen Nusrat, Mathias Toft, Uzma Abdullah, Zafar Iqbal, Shannon Terek, Fowzan S. Alkuraya, Elizabeth J. Bhoj, Reza Maroofian, Bekim Sadikovic, Hakon Hakonarson, Yuanquan Song, Dong Li
Abstract
Obesity is associated with impaired wound healing, but the mechanisms linking excess adiposity to aberrant tissue repair remain unresolved. Heterotopic ossification (HO) is a severe example of pathologic tissue repair in which mesenchymal progenitor cells (MPCs) undergo aberrant osteochondral differentiation within soft tissue, leading to joint contractures and pain. Here, we show that accumulation of dietary omega-6 (ω-6) lipids in the injury site is a key mechanism linking obesity to HO. Specifically, in mice fed a high-fat diet (HFD), injured tissues were enriched in linoleic and arachidonic acids, providing substrate for myeloid cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production. PGE2 then drove a transcriptional program in mesenchymal progenitor cells that promoted osteochondral differentiation. An isocaloric, low linoleic acid HFD reduced HO despite comparable obesity, demonstrating that dietary lipid composition, rather than adiposity alone, drove pathological repair. Clinical data mirrored these findings, showing that obesity conferred increased HO risk, and COX-2 inhibition reduced HO exclusively in obese patients. Together, these findings identify injury site ω-6 lipid enrichment as the key signal linking the diet to MPC reprogramming, pointing to dietary lipid modulation as an actionable strategy to limit HO in obesity.
Authors
Stefanie L. Moye, Monisha Mittal, Tarun Srinivasan, Sneha Korlakunta, Chase A. Pagani, Ayelet Dar, Oromo Geshow, Dylan Feist, Lauren G. Zacharias, Zhao Li, Aaron W. James, Gerta Hoxhaj, Andrew M. Smith, Katherine A. Gallagher, Thomas P. Mathews, Robert J. Tower, Benjamin Levi
Abstract
Enhanced TGFβ signaling caused by mutations in Fibrillin-1 (FBN1) in patients with Marfan syndrome (MFS) leads to myxomatous degeneration of the mitral valve (MDMV). MDMV can result in mitral valve prolapse, severe regurgitation, and sudden cardiac death. However, it remains unknown whether lymphatic vessel (LV) dysfunction contributes to MDMV development in MFS. Here, we show that lymphangiogenesis in murine mitral valves (MVs) begins postnatally. However, this process is inhibited in a mouse MFS model, Fbn1 mutant (Fbn1C1039G/+) mice, accompanied by disrupted lymphatic cell-cell junctions, impaired lymphatic drainage, and an abnormally widespread distribution of MHCII+ infiltrating macrophages. Treatment of Fbn1 mutant mice with VEGF-C156S, a selective VEGFR3 agonist, stimulates the ERK and Akt pathways, increases LV density in MVs, and ameliorates MDMV. Fbn1 mutant MVs display disorganized valvular endothelial cells (VECs) and decreased expression of the anti-inflammatory modulator Zfp36 (zinc finger protein 36) in VECs and immune cells. Treatment with FTY720 (Fingolimod), a ZFP36 activator and S1P antagonist, rescues MDMV phenotypes in Fbn1 mutant mice by reducing immune cell infiltration and restoring lymphatic cell junctions and drainage. These findings suggest that the Fbn1 mutation causes LV hypoplasia and defective lymphatic drainage in MVs, driven in part by pro-inflammatory VECs, leading to MFS-related MDMV.
Authors
Can Tan, Ziyou Ren, Shreya Kurup, Xianpeng Liu, Zhi-Dong Ge, Shodai Suzuki, Pritika Jakka, Cheryl Tang, M. Luisa Iruela-Arispe, Tsutomu Kume
Abstract
Imaging-based single-cell spatial transcriptomics (iSCST) on formalin-fixed, paraffin-embedded (FFPE) tissue enables comprehensive analysis of archived specimens while preserving spatial context, critical to an understanding of ulcerative colitis (UC) pathology. Here, we deployed a robust framework for applying iSCST to clinical FFPE mucosal biopsies from patients with UC, immune checkpoint inhibitor-induced (ICI) colitis and healthy controls. iSCST using custom Xenium gene panels enabled precise detection of diverse cell subsets and disease-specific genes. We mapped transcriptionally distinct fibroblast subsets within mucosal niches, including inflammation-associated fibroblasts (IAFs), and identified colitis-specific neighborhoods formed by IAFs, monocytes, and neutrophils. Transcriptional signatures and spatial neighborhoods uncovered through iSCST were associated with vedolizumab (VDZ) response, with non-responders exhibiting either an innate IAF-monocyte-neutrophil signature or adaptive gut-associated lymphoid tissue (GALT) signature, while responders showed enrichment of an epithelial cellular neighborhood. These signatures were validated in an internal and an external dataset, supporting the existence of two distinct archetypes of treatment resistance to VDZ in UC. This iSCST framework provides a powerful approach for analyzing FFPE tissues, offering insights into colitis-associated cellular networks and identifying biomarkers to enhance patient risk stratification in routine clinical workflows.
Authors
Elvira Mennillo, Madison L. Lotstein, Gyehyun Lee, Julian H. Hou, Vrinda Johri, Donna E. Leet, Christina A. Ekstrand, Jessica Tsui, Jun Yan He, Uma Mahadevan, Walter L. Eckalbar, Ryan M. Gill, Christopher J. Bowman, David Y. Oh, Gabriela K. Fragiadakis, Michael G. Kattah, Alexis J. Combes
Abstract
BACKGROUND. Sepsis is a leading cause of morbidity and mortality in critically ill children, yet heterogeneous immune responses complicate the development of targeted therapies and the host immune factors driving sepsis pathobiology remain unclear. METHODS. We integrated deep immune phenotyping, plasma proteomics, single-cell transcriptomics, and phosphoflow cytometry in a prospective cohort of 88 critically ill children to elucidate the mechanisms underlying immune heterogeneity. RESULTS. Unsupervised clustering of plasma cytokines identified three immunologic subgroups, including a high-severity group (“Group C”) characterized by hypercytokinemia driven by IL-6 and IFN-γ. Group C exhibited distinct alterations in immune cell frequency and activation, with a strong association between hyperinflammatory cytokine signaling and lymphocyte dysfunction. Single-cell RNA sequencing revealed transcriptional signatures of T cell activation and metabolic stress, with suppression of a lymphoid protective gene program across CD8⁺ T cell subsets. Despite increased expression of activation markers, T cell receptor repertoire analysis revealed no dominant clonotypes, consistent with bystander activation. Phosphoflow cytometry demonstrated baseline STAT1/STAT3 hyperactivation in Group C CD8⁺ T cells, which failed to respond to αCD3/αCD28/αCD49d stimulation. CONCLUSIONS. These findings define an IL‑6/IFN‑γ–driven endotype of T cell dysfunction in pediatric sepsis and highlight the JAK/STAT axis as a rational target for immunomodulatory therapy. FUNDING. K12HD047349, K23GM159013, K08AI135091, R01HD095976, Thrasher Research Foundation, Burroughs Wellcome Fund CAMS, Immune Deficiency Foundation, Primary Immune Deficiency Treatment Consortium, Barbara Brodsky Foundation, CHOP Research Institute
Authors
Robert B. Lindell, Samir U. Sayed, Jose S. Campos Duran, Sydney A. Sheetz, Apoorva Babu, Montana S. Knight, Andrea A. Mauracher, Ceire A. Hay, Peyton E. Conrey, Julie C. Fitzgerald, Nadir Yehya, Stephen T. Famularo III, Teresa Arroyo, Richard Tustin III, Hossein Fazelinia, Edward M. Behrens, David T. Teachey, Lisa R. Forbes Satter, Alexandra F. Freeman, Jenna R.E. Bergerson, Steven M. Holland, Jennifer W. Leiding, Scott L. Weiss, Mark W. Hall, Deanne M. Taylor, Rui Feng, E. John Wherry, Nuala J. Meyer, Sarah E. Henrickson
Abstract
Cardiac macrophages are broadly studied as two subtypes, tissue resident C-X3-C motif chemokine receptor 1 positive (CX3CR1+) that are also C-C motif chemokine receptor 2 negative (CCR2–), and monocyte derived CCR2+. Previous systemic loss of function approaches suggested unique roles for each subtype in the heart with CCR2+ being inflammatory and CX3CR1+ being pro-healing. Here we employed a cardiac-specific gain of function approach to selectively enhance either macrophage subtype. A robust increase in basal CCR2+ macrophages in the heart by targeted C-C motif chemokine ligand 2 (Ccl2) expression did not induce inflammation, cause fibroblast activation, or impair cardiac function. However, increased CCR2+ macrophages reciprocally diminished self-renewing tissue resident macrophages and worsened cardiac fibrosis due to pressure overload stimulation. Conversely, augmented expression of colony-stimulating factor-1 (Csf1) in the heart promoted selective expansion of resident CX3CR1+ macrophages, which exerted no pathophysiological consequences at steady-state. However, pressure overload in these mice with expanded CX3CR1+ macrophages showed a CCR2+ macrophage-dependent inflammation leading to exacerbated cardiac dysfunction, simultaneously still protecting from adverse remodeling and cardiac fibrosis. In conclusion, cardiac-specific selective enrichment of macrophage subtypes shows their intricate interplay and unique functional roles in regulating myocardial inflammation and fibrosis during hypertrophy and at homeostasis.
Authors
Rajesh K. Kasam, Ronald J. Vagnozzi, Yasuhide Kuwabara, Anne Katrine Z. Johansen, N. Scott Blair, Vikram Prasad, Suh-Chin J. Lin, Akanksha Rajput, Michelle Nieman, Jeffery D. Molkentin
Abstract
Men with advanced prostate cancer are typically treated with androgen deprivation therapy, but most ultimately develop resistance and incurable disease (e.g. castration-resistant prostate cancer (CRPC)). The majority of CRPCs overexpress the epigenetic enzyme EZH2 and harbor alterations in the PI3K pathway, providing two targetable pathways outside of AR. Here we show that EZH2 inhibitors synergize with PI3K, AKT, or mTORC1 inhibitors to kill CRPC in vitro and promote tumor regression in vivo. Strikingly, these agents trigger a catastrophic energy crisis by cooperatively suppressing glycolysis, the TCA cycle, and oxidative phosphorylation prior to cell death. EZH2 and PI3K pathway inhibitors achieve this by respectively inhibiting two key regulators of metabolism, MYC and HIF-1A, while concomitantly derepressing a pro-apoptotic stress sensor. Together, these studies reveal a promising therapeutic strategy for CRPC and demonstrate how metabolic plasticity can be fatally impaired by co-targeting upstream oncogenic nodes that converge on this important process.
Authors
Rhea Sahu, Miriam Enos, Swastika Sharma, Amy E. Schade, Alycia Gardner, Akiko Yoshinaga, Alexandra Indeglia, Eleanor Minogue, Songhua Hu, Kiran Kurmi, Shakchhi Joshi, Daniel R. Schmidt, Samkyu Yaffe, Van T.M. Nguyen, Fang Xie, Steven P. Balk, Matthew G. Vander Heiden, Kristian Helin, Marcia C. Haigis, Karen Cichowski
Abstract
Clonal hematopoiesis (CH) is the age-related expansion of mutated hematopoietic stem cells without hematologic abnormalities. In patients with solid tumors, CH is associated with higher mortality and may evolve to therapy-related myeloid neoplasms; however, the mechanisms by which cancer treatments promote CH dynamics remain largely unknown. Here, we analyzed 392 serial samples from a prospective cohort of breast cancer patients and showed that cytotoxic treatments led to strong therapeutic bottlenecks, resulting in significant reductions in hematopoietic allelic populations and differential clonal selection. Positively selected CH that expanded through dose-dependent therapeutic bottlenecks harbored mutations in TP53, PPM1D, SRCAP, DNMT3A, and YLPM1. Patients with positively selected CH during treatment had the shortest progression-free and overall survival compared to patients with unchanging or negatively selected CH across all therapies. These findings, validated in independent breast cancer and pan-cancer cohorts, provide strong evidence for clinical relevance of monitoring CH during cancer treatment.
Authors
Mona Arabzadeh, Yi-Han Tang, Christelle Colin-Leitzinger, Sadegh Marzban, Daniel Walgenbach, Stefania Morganti, Vaidhyanathan Mahaganapathy, Erika Harper, Mingxiang Teng, Jacob K. Kresovich, Iman Washington, Heather A. Parsons, Judy E. Garber, Jeffrey West, Shridar Ganesan, Hossein Khiabanian, Nancy Gillis
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ISSN: 0021-9738 (print), 1558-8238 (online)