Mazloum et al. report that polycystin-1 and the primary cilium govern the composition, mechanics, and shape of the tubular basement membrane, and that remodeling of this matrix initiates tubule dilation in autosomal dominant polycystic kidney disease. The cover image is a false-colored transmission electron micrograph of the thinned tubular basement membrane separating two polycystin-1–deficient tubular cells.
Background. Myelodysplastic syndromes (MDS) are characterized by aberrant DNA methylation, and mutations in epigenetic modifiers are frequently found in these patients. Although DNA methyltransferase inhibitors (DNMTi) are used to treat MDS, response variability remains a challenge in the clinic, with limited predictive markers. Methods. We integrated genomic, epigenomic, and transcriptomic analyses of 98 MDS patients. Patients were classified into epigenetic subtypes via hierarchical clustering. Random forest classifiers were developed and validated using internal stratified testing and an independent external cohort to predict AZA response. Results. MDS is characterized by widespread DNA hypomethylation affecting distal regulatory elements. We identified seven epigenetic clusters correlated with distinct molecular drivers. Notably, Cluster VI exhibited low mutational burden but a high AZA response rate of 71% (P ≤ 0.01). While transcriptional profiles alone failed to distinguish responders, a DNAme-based classifier achieved an area under the curve (AUC) of 0.82. An integrative model combining DNAme, gene expression, mutations, and clinical parameters achieved an AUC of 0.93 in internal validation and 0.88 in the external cohort. Conclusion. Epigenetic signatures at distal genomic elements provide superior predictive power for AZA response compared to promoter-centric or transcriptional analyses. These findings establish a robust framework for personalized treatment strategies in MDS.
Qin Yang, Miguel Torres-Martin, Masataka Taguchi, Alice Brogi, Irene Casalin, Eleonora Ceneri, Stephanie Halene, Amy E. DeZern, Elizabeth A. Griffiths, Matilde Y. Follo, Carlo Finelli, Jerald P. Radich, Michael J. Rauh, Rafael Bejar, Mikkael A. Sekeres, Valeria Santini, Maria E. Figueroa
Despite enormous advances in clinical genomics, idiopathic scoliosis remains an enigmatic condition with poorly understood genetic and pathophysiological underpinnings impeding molecular diagnosis and the development of targeted treatments. We performed linkage analysis, exome, genome and short- and long-read RNA sequencing in a multigenerational family affected by autosomal dominant early-onset scoliosis (EOS) with a unique pattern of spondylodysplastic elements and progressive endplate erosion and identified the LRR binding FLII interacting protein 1 gene (LRRFIP1) as the disease-causing gene. The underlying cause is a rare noncoding variant altering transcription factor binding of NR3C1 (glucocorticoid receptor) leading to changes in LRRFIP1-isoform expression. Transcriptomic changes in fibroblasts of affected individuals indicated a combination of disturbed Wnt-signaling during somitogenesis, planar cell polarity signaling and postnatal inflammatory dysregulation with clinical and molecular overlaps with Ankylosing Spondylitis and Scheuermann kyphosis. We conducted a rare variant enrichment analysis using genome data from 484,903 UK Biobank participants and found an enrichment of rare risk-increasing LRRFIP1-variants in individuals with scoliosis. Our analysis of an Lrrfip1tm1.1(KOMP)Wtsi KO mouse model showed increased prevalence of idiopathic kyphoscoliosis in Lrrfip1-deficient mice. Our work provides insights into the pathophysiology of rare and common spinal disorders and hints to potential future therapeutic approaches with selective NR3C1-inhibitors.
Tanja Frey, Elena M. Cabello, Gabriele Siegel, Carla Bello, Rike Schiller, Martina A. Trippel, Neguin Ranjbar, Paranchai Boonsawat, Stephanie E. van Gijn, Ivan Ivanovski, Michael Papik, Markus Zweier, Kan Min, Katharina Steindl, Anita Rauch
Recent studies have revealed that, beyond their classical role in platelet production, megakaryocytes (MKs) express immune-related genes and exert important immunoregulatory functions. However, it remains unclear whether these functions arise from a single versatile population or from distinct specialized subtypes, and how such subtypes influence infection and inflammation. Here, we identified three specialized immune MK subtypes (imm-MKs)—macrophage-like MKs (Mac-MKs), neutrophil-like MKs (Neu-MKs), and antigen-presenting MKs (APC-MKs)—each defined by distinct transcriptional programs and regulatory networks, with comparable heterogeneity observed in human MKs. Developmental analyses showed that MK immune-related programs increased with maturation and that immune MK subtypes exhibited distinct tissue- and stage-dependent patterns. Functionally, MK subtypes exhibited phase-specific responses during bacterial pneumonia: early infection preferentially induced Mac-MKs and Neu-MKs, which contributed to pulmonary inflammation, whereas during the post-peak acute-to-early-recovery stage, APC-MKs supported a Treg-associated regulatory program that contributed to pulmonary inflammatory control. This MK–Treg axis uncovers a previously unrecognized mechanism of hematopoietic–immune crosstalk. Collectively, our study delineates organ- and stage-specific immune specialization of MKs and identifies immune MK subtypes as dynamic contributors to phase-specific inflammatory and Treg-linked regulatory programs during development and infection.
Huizhen He, Yezi Ma, Yifei Cai, xiaoyuan chen, Tianran Cheng, Ziqi Huo, Sibei Guo, Meijuan Xia, Dan Feng, Minmin Li, Jingjing Zhao, Nananan Zhao, Pei Su, Wen Zhou, Fei Wang, Cuicui Liu, Hongtao Wang, Jiaxi Zhou
Low-dose interleukin-2 (IL-2) and IL-2 muteins are being developed to expand regulatory T cells (Tregs) for autoimmune disease therapy, but injection site reactions (ISRs) remain frequent and poorly understood. Here we show IL2Mut24, a murine surrogate of IL-2 receptor α (IL-2Rα, CD25)-biased IL-2 mutein, enhances Treg expansion yet paradoxically exacerbates cutaneous inflammation compared to wild-type IL-2. Using immunodeficient mice, antibody blockade and adoptive transfer, we identify group 2 innate lymphoid cells (ILC2s) as key drivers of IL-2-induced skin inflammation, defining a CD25-dependent innate activation axis that constrains immune tolerance. In cynomolgus monkeys, the CD25-biased IL-2 mutein efavaleukin alfa promotes greater peripheral Treg expansion than aldesleukin (recombinant human IL-2) but is accompanied by transient increases in IL-5 and dose-dependent ISRs, indicating conservation of this innate inflammatory program across species. To improve the therapeutic window, we engineer receptor clamps by linking IL2Mut24 to antibodies against CD25 to restrict IL-2 access to CD25. This receptor-tuned IL-2 preserves Treg selectivity, suppresses ISRs, and outperforms IL2Mut24 in experimental autoimmune encephalomyelitis by restraining Th17 responses. These findings reveal a conserved innate mechanism underlying IL-2–associated toxicity and establish receptor-tuning as a strategy to improve the safety and efficacy of IL-2–based immunotherapy.
Anupama Sahoo, Cody Moorman, Mina Tsenkova, Yi Jing, Alexis Valdovinos, Xin Luo, Shiping Lu, Songyu Wang, Renee R. Hukkanen, Madeline Fort, Helen S.H. Tang, Ronya Primack, Shweta Mandavalli, Weiwen Deng
Atrial fibrillation (AF) is the most common sustained human cardiac arrhythmia and linked to a drastic increase in stroke and heart failure risk. While sequence variations in the PITX2 non-coding region are the strongest genetic signature of AF risk, the direct role of PITX2 in AF remains a topic of debate. Here, we generated a mouse model (Pitx2Pro41Ser) of a human PITX2 coding variant linked to increased AF risk in the Finnish population. The Pitx2Pro41Ser mice exhibit near-complete penetrance of pacing-induced AF, and transcriptional profiling indicates that Pitx2Pro41Ser is a loss-of-function mutation. In vivo cleavage under targets and tagmentation (CUT&Tag) reveals that PITX2 acts as a transcriptional repressor in developing left atrial cardiomyocytes independent of DNA methylation. Ectopic Pitx2 expression in postnatal right atrial cardiomyocytes via adeno-associated virus (AAV) delivery or genetic overexpression represses right atrial genes and induces a left atrial transcriptome, revealing unexpected plasticity of postnatal atrial cardiomyocytes. Strikingly, delivery of Pitx2 AAV into Pitx2Pro41Ser mice rescues AF inducibility uncovering a direct link between PITX2 activity and AF susceptibility.
Jeffrey D. Steimle, Yue Yuan, Shaohai Fang, Vaibhav Deshmukh, Christine Rodriguez, Fansen Meng, Taotao Tan, Md. Abul Hassan Samee, Yun Huang, Na Li, James F. Martin
The cyclic GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING) pathway is a key component of innate immunity, linking DNA detection to inflammatory and antiviral responses. Originally identified as a sensor for microbial DNA, cGAS is now understood to also respond to endogenous cytosolic DNA, and the pathway has been implicated in a wide range of physiological and pathological processes, including cancer, autoimmunity, neuroinflammation, and aging. This review series, organized by Dr. Alex Stegh, consolidates current knowledge and highlights emerging developments that may lead to therapeutic targeting of the cGAS-STING pathway across a range of disorders.
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