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Abstract
Kleefstra syndrome (KLEFS1) results from EHMT1 haploinsufficiency and is characterized by variable neurodevelopmental delays and psychopathology. Developmental regression, marked by the sudden loss of previously acquired daily life skills during late puberty or early adulthood, has emerged as a severe complication in individuals with KLEFS1. To investigate the clinical and molecular mechanisms underlying developmental regression and assess the therapeutic potential of olanzapine, we conducted a sequential study in an international cohort of fifty-four individuals with KLEFS1. Among sixteen individuals treated with olanzapine, ten exhibited a beneficial response based upon improvement of their adaptive functioning, and four showed temporary improvement. These clinical findings informed preclinical studies using human induced pluripotent stem cell-derived and ex-vivo cortical slices from a mouse model of KLEFS1. We identified hyperactivity in EHMT1+/– neuronal networks co-cultured with EHMT1+/– astrocytes, a dysfunction reversible by olanzapine. Mechanistically, EHMT1+/– astrocytes displayed elevated levels of S100B, a neuroinflammatory marker contributing to neuronal network hyperactivity. Notably, olanzapine treatment reduced S100B levels, and pharmacological inhibition or genetic knockdown of S100B in EHMT1+/– astrocytes was sufficient to rescue the neuronal hyperactivity phenotype. These findings underscore a critical role for astrocytes in KLEFS1 pathophysiology and identify a potential cellular target for olanzapine in mitigating developmental regression.
Authors
Karlijn Vermeulen-Kalk, Shan Wang, Joost Kummeling, Britt Mossink, Kim N. Wijnant, Carlos O. González Jiménez, Zoe J. Frazier, Brian J. Rozumny, Anne O'Donnell-Luria, Ellen Hanson, Monica Frega, Katrin Linda, Moritz Negwer, Bas Lendemeijer, Astrid Oudakker, Monica Pop-Purceleanu, Joost G.E. Janzing, Linde van Dongen, Femke M.S. de Vrij, Steven A. Kushner, Ilse van der Werf, Chantal Schoenmaker, Wouter Oomens, Siddharth Srivastava, Jos I.M. Egger, Hans van Bokhoven, Dirk Schubert, Nael Nadif Kasri, Tjitske Kleefstra
Abstract
Reproductive aging is characterized by a progressive decline of reproductive function, with broad implications for overall health and longevity. Environmental factors, including assisted reproductive technologies (ART), can accelerate reproductive aging by promoting premature ovarian failure in females. In vitro fertilization (IVF) though widely used and generally considered safe, has been associated with lasting effects on offspring health. Using a mouse model that closely approximates human IVF, we demonstrated that IVF accelerates reproductive aging in female offspring by inducing premature ovarian failure. IVF-conceived females exhibited altered ovarian function, reduced follicle reserve, disrupted endocrine profiles, and transcriptomic and epigenetic changes consistent with premature reproductive decline. These findings reveal long-term consequences of IVF on female reproductive health and highlight the need to understand how early-life interventions influence reproductive longevity.
Authors
Eric A. Rhon-Calderon, Cassidy N. Hemphill, Alexandra J. Savage, Ana Domingo-Muelas, Zhengfeng Liu, Christopher J. Krapp, Laren Riesche, Nicolas Plachta, Richard M. Schultz, Marisa S. Bartolomei
Abstract
The inflammatory response resulting from the abnormal accumulation of metabolites has been implicated in the pathogenesis of organ fibrosis; however, its role and underlying mechanisms in renal fibrosis remain unclear. In this study, we observed a negative correlation between fumarate hydratase (FH) expression and the degree of renal fibrosis. Loss of FH function was associated with heightened inflammation and exacerbated tubulointerstitial damage in the kidney. Moreover, FH deficiency aggravated fibrosis in both the liver and lungs. Mechanistically, the depletion of FH in renal tubular cells led to fumarate accumulation. Fumarate directly succinated A-kinase anchoring protein 12 at cysteine 670, thereby diminishing its capacity to inhibit the activity of protein kinase Cζ (PKCζ). This process exacerbated renal inflammation and fibrosis by activating the downstream PKCζ/NF-κB and PKCζ/β-catenin pathways. Additionally, the upregulation of FH through adeno-associated virus 2/9-mediated FH overexpression markedly mitigated renal inflammation and fibrosis. These findings highlighted the important role of fumarate accumulation in the advancement of renal fibrosis, supporting FH as a potential therapeutic target in renal fibrosis.
Authors
Shuai Sun, Xu-yang Yan, Yu-hang Dong, Jian-min You, Zhen-yu Guo, Dong-xue Lv, Shuai-shuai Xie, Rui Hou, Xiang-yu Li, Ju-tao Yu, Xiao-yu Shen, Jie Wei, Zhen-yu Song, Zi-qi Chen, Yun-long Zhu, Xing-xin Xu, Juan Jin, Jia-gen Wen, Hao Wang, Xiao-ming Meng, Wei Wang
Abstract
Autosomal dominant polycystic kidney disease (ADPKD), the leading genetic cause of kidney failure, results from loss-of-function mutations in PKD1, encoding polycystin-1 (PC1). PC1 localizes to the primary cilium. In the absence of PC1, adverse signaling from the primary cilium orchestrates cyst formation, but the biomechanical underpinnings of this cilia-dependent cyst activation (CDCA) remain unclear. Combining tubule-specific orthologous mouse models with a tubule-on-chip platform, we show that PC1 and cilia govern the composition, mechanical properties and shape of the tubular basement membrane (TBM), the principal rigid determinant of tubule geometry. PC1 loss triggers TBM thinning, heparan sulfate enrichment and deformation, leading to distension, preferentially of the distal nephron. These changes are driven by a cilia-dependent transcriptional program, with GLIS2 — a key CDCA effector — participating as a downstream mediator. Reduction of TBM stiffness amplifies Pkd1−/− tubule-on-chip dilation and increases cyst formation in vivo. Conversely, increasing luminal pressure through ureteral obstruction induces disproportionate distension of Pkd1-deficient tubules and triggers an irreversible cystogenic program. Together, these findings establish a TBM-centered biomechanical model of ADPKD in which tubule deformation is governed by both basolateral and luminal mechanical factors, and identify the cilium–TBM axis, operating in part through GLIS2, as a central driver of cystogenesis.
Authors
Manal Mazloum, Brice Lapin, Rushdi Alghamdi, Jessica Vandensteen, Martine Burtin, Pascal Houillier, Lydie Cheval, Gilles Crambert, Vicky Scata, Camille Cohen, Christoph Schell, Michael Rehman, Amandine Aka, Karim Ourahmoun, Rui Benedito, E. Wolfgang Kuehn, Stéphanie Descroix, Tilman Busch, Michael Köttgen, Serge Garbay, Marie-Christine Verpont, Ellie Tang, Brigitte Lelongt, Nicolas Cagnard, Stefan Somlo, Sylvie Coscoy, Fabiola Terzi, Amandine Viau, Frank Bienaimé
Abstract
Metastatic castration-resistant prostate cancer (mCRPC) is an aggressive subtype of prostate cancer (PC) without curative treatments. Antibody-drug conjugates (ADCs) emerged as promising cancer therapeutics that selectively deliver cytotoxic agents (payloads) to the tumors. Although ADCs have been successfully applied in the treatment of hematological and solid tumors, ADC monotherapy has not demonstrated durable responses in mCRPC, and the mechanisms of PC resistance to ADCs have not been thoroughly investigated. Our study aimed to improve ADC efficacy using a new integrated approach for the custom ADC design and multiplexing. To nominate rational combinations of ADC targets and ADC payloads, we (1) examined protein co-expression of three clinically relevant surface antigens - B7 homolog 3 (B7-H3), prostate specific membrane antigen (PSMA), and six-transmembrane epithelial antigen of prostate-1 (STEAP1) - in a series of human mCRPCs, and (2) screened established ADC payloads and their combinations in mCRPC cell lines with different molecular backgrounds. Identified synergistic interactions between DNA-damaging payloads and BCL-XL inhibitor A-1331852 as well as their coordinated induction of intrinsic apoptosis pathway were evaluated in a panel of PC cell lines. Functional relevance between isolated p53 loss and PC responses to three genotoxic ADCs - B7-H3 - seco-DUBA (vobramitamab duocarmazine), PSMA - SG3249, and STEAP1 – DXd and their combinations with A-1331852 was established using genetic knockout models. Lastly, enhanced in vivo antitumor activity of vobramitamab duocarmazine by systemic A-1331852 was shown. Collectively, our findings provide rationale for the development of ADC therapies combining genotoxic payloads with BCL-XL inhibitors for mCRPC.
Authors
Galina Semenova, Sander B. Frank, Ruth Dumpit, Wanting Han, Ilsa Coleman, Roman Gulati, Canan D. Dirican, Tarana Arman, Jessica Maruwan, Colm Morrissey, Michael C. Haffner, Peter S. Nelson, John K. Lee
Abstract
Obesity is increasingly implicated in hematopoietic malignancies, yet its role in mutation-driven myeloid leukemias remains unclear. Using UK Biobank data from over 440,000 individuals, we found obesity traits including elevated BMI and waist-to-hip ratio were associated with type 2 diabetes, increased plasma IL-17A (interleukin-17A), reduced GLP-1R (glucagon like peptide 1 receptor) expression, and heightened risk of myeloid malignancies. Transplantation of protein tyrosine phosphatase non-receptor type 11, PTPN11 (Shp2E76K/+) mutant hematopoietic stem/progenitors into obese mice demonstrated that metabolic inflammation accelerates leukemogenesis via myeloid cell expansion, lipid metabolic rewiring, IL-17A activation, and accumulation of M2-like tumor-associated macrophages (TAMs), accompanied by T-cell exhaustion and impaired antigen presentation. Notably, dual therapy with an anti-IL-17A antibody and a GLP-1R agonist reversed these effects, by reducing M2-like TAMs, restoring Ciita-dependent antigen presentation, Tyk2-mediated IFNγ signaling, reactivated T-cell responses, and reducing leukemic burden. These findings establish IL-17A driven, metabolism-coupled immunosuppression as a mechanistic link between obesity and SHP2-mutant myeloid leukemias, highlighting a tractable therapeutic strategy for high-risk obese patients.
Authors
Reuben Kapur, Linke Li, Rahul Kanumuri, Kanaka Sai Ram Padam, Baskar Ramdas, Chiranjeevi Pasala, Gabriela Chiosis, Lakshmi Reddy Palam, Ramesh Kumar, Satoshi Koyama, Pradeep Natarajan, Laura S. Haneline, Zhi Yu, Santhosh Kumar Pasupuleti
Abstract
Dominant mutations in Progranulin (GRN) gene cause frontotemporal lobar degeneration (FTLD-GRN), whereas homozygous GRN mutations lead to neuronal ceroid lipofuscinosis, a childhood neurodegenerative disorder. While recent transcriptomic studies reveal profound glial and neuronal pathology in FTLD-GRN at the disease end stage, the mechanism that disrupts glia-neuron homeostasis remains unclear. Using induced pluripotent stem cell (iPSC)-derived cortical organoids, we showed that GRN-/- and GRNR493X mutations lead to precocious astrogliosis that promotes neuronal stress and synaptic loss. Single-cell transcriptomics and histopathology analyses revealed a robust activation in TGFb signaling pathway in GRN-/- and GRNR493X/R493X astrocytes, which was accompanied by features of immune activation, loss of synaptic support, and abundant pTDP-43+ fibrils in astroglial cytoplasm, a feature characteristic of FTLD-GRN. Intriguingly, blocking TGFb signaling mitigated astroglial activation and pTDP-43 proteinopathy in GRN-/- organoids. Together, these results provide new insights into the cell-autonomous role of astroglial activation in neurodegeneration caused by Progranulin deficiency.
Authors
Arren C. Ramsey, Xiao-Yan Tang, Magdalena J. Macias, Patricia R. Nano, Rufei Lu, Brian Benito, Cameron M. Lau, Jisu Park, Jiasheng Zhang, Wandy Beatty, Tanzila Mukhtar, Arnold R. Kriegstein, Aparna Bhaduri, Elise Marsan, Eric J. Huang
Abstract
CIC::DUX4 sarcoma (CDS) is a lethal cancer driven by a fusion between tumor suppressor Capicua (CIC) and pioneer transcription factor double homeobox 4 (DUX4). We previously generated three genetically engineered mouse models (GEMMs) of CDS with CIC::DUX4 regulated by loxP-STOP-loxP cassettes, however, all three models developed spontaneous tumors without Cre recombinase. Here, we established a next-generation GEMM of CDS (dFLEx CDS) that employs a dual recombinase (Cre + FLPE) FLEx-switch design to activate CIC::DUX4 expression and initiate sarcomagenesis in a spatially and temporally-controlled manner. Because CIC::DUX4 drives sarcoma development by activating a oncogenic transcriptional program, we performed a drug screen on human-derived CDS cell lines using a library of compounds that modulate transcription. This screen identified Minnelide, an inhibitor of RNA polymerase II-mediated transcription, as a selective inhibitor of CDS. Mechanistically, Minnelide acted through xeroderma pigmentosum type B to alter phosphorylation of RPB1, the largest subunit of RNA polymerase II. Subsequently, RPB1 underwent degradation leading to apoptosis of CDS cells. Minnelide demonstrated in vivo efficacy in dFLEx CDS GEMMs and in human CDS xenografts. As Minnelide has already been demonstrated to be safe in clinical trials, these findings nominate Minnelide as a potential therapeutic option to test in CDS patients.
Authors
MaKenna R. Browne, Axel V. Silver, Risha Banerjee, Brendan C. Dickson, Benigno Aquino, Kristianne M. Oristian, Jonathon E. Himes, Peter G. Hendrickson, David G. Kirsch
Abstract
Most mitochondrial proteins are nuclear encoded, translated in the cytosol, and imported into the mitochondria. Through gene expression analysis and functional assays, we demonstrated that mitochondrial protein import is increased in acute myeloid leukemia (AML) cells compared to normal hematopoietic cells. Increased mitochondrial protein import was positively correlated with increased mitochondrial unfolded protein response (UPRmt), a stress activated pathway of mitochondrial proteases and chaperones that maintains protein solubility and prevents the formation of toxic aggregates. The UPRmt protease LONP1 (Lon Peptidase 1) was upregulated in AML and positively correlated with increased mitochondrial protein import and UPRmt. Genetically or chemically inhibiting the LONP1 ATPase domain induced mitochondrial protein aggregation and selectively killed AML cells with high LONP1 expression while sparing AML cells with low LONP1 expression and normal hematopoietic cells in vitro and in vivo. Thus, we uncovered a critical role of the UPRmt protease LONP1 in buffering stress from mitochondrial protein import in AML.
Authors
Matthew Tcheng, Veronique Voisin, Geethu Emily Thomas, Anastasija A. Piric, Marcela Gronda, Rose Hurren, Dakai Ling, Yongran Yan, Lan Xin Zhang, Yue Feng, Ali Chegini, Nathan Duong, Ross S. Mancini, Stefan Quinn W. Currie, Zaynab Mamai, Brady Stock, Shahbaz Khan, Yulia Jitkova, Chaitra Sarathy, Edward Ayoub, Po Yee Mak, Andrea Arruda, Thomas Kislinger, Mark Reed, Bing Z. Carter, Michael Andreeff, Steven M. Kornblau, Mark D. Minden, Siavash Vahidi, Aaron D. Schimmer
Abstract
Renal water reabsorption is classically regulated by vasopressin V2 receptor (V2R) signaling through cyclic AMP and protein kinase A, driving apical accumulation of aquaporin-2 (AQP2). However, collecting duct water handling is also modulated by vasopressin-independent mechanisms. Here, we examined intracellular soluble urate as a vasopressin-independent regulator of AQP2 trafficking. Intracellular urate accumulation in collecting duct cells was mediated by enhanced apical urate uptake via GLUT9b and reduced apical urate efflux through ABCG2, triggering phosphodiesterase-4 activation, reduced cAMP, and downstream AMP-activated protein kinase (AMPK) activation. The resulting AQP2 accumulation at the apical membrane was independent of V2R signaling, required ongoing endocytosis and was associated with features of post-endocytic apical trafficking of internalized AQP2. In vivo ABCG2 inhibition with probenecid increased apical AQP2 abundance and markedly attenuated tolvaptan-induced polyuria in both wild-type and Pkd1RC/RC autosomal dominant polycystic kidney disease (ADPKD) mice in a uricase-independent manner, while preserving tolvaptan’s ADPKD-modifying efficacy. In a Phase 2 trial with tolvaptan-treated ADPKD patients, probenecid reduced urine volume and nocturia frequency. Together, these findings support a vasopressin-independent urate–AMPK–AQP2 pathway that regulates renal water handling and, in a preclinical ADPKD model, can uncouple cyst growth attenuation from the dose-limiting aquaretic effects of V2R antagonism.
Authors
Mohamad Hadla, Jean Marc Mardirossian, Daniel G. Bichet, Abdul Hamid Borghol, Georges Abboud, Ahmad Ghanem, Eduardo N. Chini, Peter C. Harris, Vicente E. Torres, Seth L. Alper, Volker Vallon, Fouad T. Chebib
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Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)