Cell biology
Abstract
Achondroplasia (ACH) and hypochondroplasia (HCH), the two most common types of dwarfism, are each caused by FGFR3 gain-of-function mutations that result in increased FGFR3 signaling, disrupting chondrogenesis and osteogenesis resulting in disproportionately shortened long bones. In this study, TYRA-300, a potent and selective FGFR3 inhibitor, was evaluated in three genetic contexts: wild-type mice, the Fgfr3Y367C/+ mouse model of ACH, and the Fgfr3N534K/+ mouse model of HCH. In each model, TYRA-300 treatment increased naso-anal length, tibia and femur length. In the two FGFR3-altered models, TYRA-300-induced growth partially restored the disproportionality of long bones. Histologic analysis of the growth plate in Fgfr3Y367C/+ mice revealed that TYRA-300 mechanistically increased both proliferation and differentiation of chondrocytes. Importantly, children with ACH can experience medical complications due to foramen magnum stenosis, and TYRA-300 significantly improved the size and shape of the skull and foramen magnum in Fgfr3Y367C/+ mice. Spinal stenosis is also a frequent complication, and TYRA-300 increased the lumbar vertebrae length and improved the shape of the intervertebral discs in both models. Taken together, these studies demonstrate that the selective FGFR3 inhibitor TYRA-300 led to a significant increase in bone growth in two independent FGFR3-driven preclinical models as well as in wild-type mice.
Authors
Jacqueline H. Starrett, Clara Lemoine, Matthias Guillo, Chantal Fayad, Nabil Kaci, Melissa Neal, Emily Pettitt, Melissandre Pache, Qing Ye, My Chouinard, Eric L. Allen, Geneviève Baujat, Robert L. Hudkins, Michael B. Bober, Todd Harris, Ronald V. Swanson, Laurence Legeai-Mallet
Abstract
Dipeptidase-1 (DPEP1) is highly upregulated in colorectal cancer (CRC), with its enzymatic function linked to invasion and metastasis. More recently, DPEP1 was found to serve as a receptor for neutrophils when expressed by activated endothelial cells. It is unknown whether neutrophils bind to DPEP1-expressing CRC cells and whether this impacts features of CRC. Neutrophils have been shown to be tumor-promoting in cancers including CRC, where they act to exclude CD8+ T cells. Herein, we show that neutrophils bind DPEP1-expressing CRC cells. In addition, DPEP1 is preferentially expressed in microsatellite stable (MSS) CRC, in which there are a paucity of CD8+ T cells, whereas DPEP1 is negatively correlated with microsatellite unstable (MSI-H) CRC, which are T cell-rich and are more responsive to immunotherapy. Remarkably, carcinogen-treated Dpep1 null mice develop multiple, large, plaque-like, locally invasive adenocarcinomas and squamous cell cancers in the distal colon. These adenocarcinomas exhibit a marked reduction of neutrophils and an influx CD8+ T cells, along with reduced expression of mismatch repair proteins, consistent with features of MSI-H CRC. These results establish DPEP1’s importance in maintaining MSS CRC and its ability to shape the tumor microenvironment.
Authors
Sarah E. Glass, Matthew E. Bechard, Zheng Cao, Radhika Aramandla, Ping Zhao, Samuel T. Ellis, Emily H. Green, Elizabeth G. Fisher, Ryan T. Smith, Chelsie K. Sievers, Maria Johnson Irudayam, Frank Revetta, M. Kay Washington, Gregory D. Ayers, Cody N. Heiser, Alan J. Simmons, Yanwen Xu, Yu Wang, Annika Windon, Martha J. Shrubsole, Nicholas O. Markham, Qi Liu, Ken S. Lau, Robert J. Coffey
Abstract
Non–small cell lung cancer (NSCLC) is a common cause of cancer-related deaths worldwide, and its incidence has been increasing in recent years. While targeted therapies like osimertinib, an epidermal growth factor receptor tyrosine kinase inhibitor, have brought about notable improvements in patient outcomes for advanced NSCLC, the challenge of acquired drug resistance persists. Here, we found that cellular mesenchymal-epithelial transition factor (c-Met) was highly expressed in osimertinib-resistant cells, and depletion of c-Met markedly inhibited the growth of osimertinib-resistant cells ex vivo and in vivo, suggesting that c-Met is a potential target to address osimertinib resistance. Through a screening process using a natural product compound library, we identified piperlongumine as a potent inhibitor to overcome osimertinib resistance. Furthermore, the combined treatment of piperlongumine and osimertinib exhibited robust antitumor effects in resistant cells, partially restoring their sensitivity to osimertinib. Additionally, we discovered that piperlongumine could enhance the interaction between E3 ligase RNF4 and Sp1, inhibit the phosphorylation of Sp1 at Thr739, facilitate the ubiquitination and degradation of Sp1, lead to c-Met destabilization, and trigger intrinsic apoptosis in resistant cells. In summary, our study sheds light on the potential of piperlongumine in overcoming osimertinib resistance, offering new strategies and perspectives for the clinical management of drug-resistant NSCLC.
Authors
Ruirui Wang, Qiang Wang, Jinzhuang Liao, Xinfang Yu, Wei Li
Citation Information: JCI Insight. 2025;10(6):e185508. https://doi.org/10.1172/jci.insight.185508.
Abstract
The osteo-oto-hepato-enteric (O2HE) syndrome is a severe autosomal recessive disease ascribed to loss-of-function mutations in the Unc-45 myosin chaperone A (UNC45A) gene. The clinical spectrum includes bone fragility, hearing loss, cholestasis, and life-threatening diarrhea associated with microvillus inclusion disease–like enteropathy. Here, we present molecular and functional analysis of the UNC45A c.710T>C (p.Leu237Pro) missense variant, which revealed a unique pathogenicity compared with other genetic variants causing UNC45A deficiency. The UNC45A p.Leu237Pro mutant retained chaperone activity, prevented myosin aggregation, and supported proper nonmuscle myosin II (NMII) filament formation in patient fibroblasts and human osteosarcoma (U2OS) cells. However, the mutant formed atypically stable oligomers and prevented chaperone-myosin complex dissociation, thereby inhibiting NMII functions. Similar to biallelic UNC45A deficiency, this resulted in impaired intracellular trafficking, defective recycling, and abnormal retention of transferrin at various endocytic sites. In particular, coexpression of wild-type protein attenuated the pathogenic effects of the variant by inhibiting excessive oligomer formation. Our results elucidate the pathogenic mechanisms and recessive characteristics of this variant and may aid in the development of targeted therapies.
Authors
Stephanie Waich, Karin Kreidl, Julia Vodopiutz, Arzu Meltem Demir, Adam R. Pollio, Vojtěch Dostál, Kristian Pfaller, Marianna Parlato, Nadine Cerf-Bensussan, Rüdiger Adam, Georg F. Vogel, Holm H. Uhlig, Frank M. Ruemmele, Thomas Müller, Michael W. Hess, Andreas R. Janecke, Lukas A. Huber, Taras Valovka
Abstract
Mitogen-activated protein kinase 8 interacting protein 3 (MAPK8IP3/JIP3) is a member of the kinesin family known to play a role in axonal transport of cargo. Mutations in the gene have been linked to severe neurodevelopmental disorders, resulting in developmental delay, intellectual disability, ataxia, tremor, autism, seizures, and visual impairment. A patient who has a missense mutation in the MAPK8IP3 gene (c. 1714 C>T, Arg578Cys) (R578C) manifests dystonia, gross motor delay and developmental delay. Here we show that the mutation is a toxic gain of function mutation which alters the interactome of JIP3, disrupts axonal transport of late endosomes, increases signaling via c-Jun N-terminal kinase (JNK), resulting in apoptosis, and disrupts the dopamine receptor 1 (D1) signaling while not affecting the dopamine receptor 2 (D2) signaling. Further, in the presence of the mutant protein, we show that 80% reduction of mutant JIP3>80% and 60% reduction of wild-type JIP3 by non-allele selective phosphorothioate (PS)-modified antisense oligonucleotides (ASOs) is well tolerated by several types of cells in vitro. Our study identifies several important new roles for JIP3 and provides important insights for therapeutic approaches, including antisense oligonucleotide reduction of JIP3.
Authors
Wei Zhang, Swapnil Mittal, Ria Thomas, Anahid Foroughishafiei, Ricardo Nunes Bastos, Wendy K. Chung, Konstantina Skourti-Stathaki, Stanley T. Crooke
Abstract
Inflammation is a critical pathological process in myocardial infarction. Although immunosuppressive therapies can mitigate inflammatory responses and improve outcomes in myocardial infarction, they also increase the risk of infections. Identifying novel regulators of local cardiac inflammation could provide safer therapeutic targets for myocardial ischemia/reperfusion injury. In this study, we identified a previously unknown micropeptide, which we named Inflammation Associated MicroPeptide (IAMP). IAMP is predominantly expressed in cardiac fibroblasts, and its expression is closely associated with cardiac inflammation. Down-regulation of IAMP promotes, whereas its overexpression prevents, the transformation of cardiac fibroblasts into a more inflammatory phenotype under stressed/stimulated conditions, as evidenced by changes in the expression and secretion of pro-inflammatory cytokines. Consequently, loss of IAMP function leads to uncontrolled inflammation and worsens cardiac injury following ischemia/reperfusion surgery. Mechanistically, IAMP promotes the degradation of HIF-1α by interacting with its stabilizing partner HSP90, and thus suppresses the transcription of pro-inflammatory genes downstream of HIF-1α. This study underscores the significance of fibroblast-mediated inflammation in cardiac ischemia/reperfusion injury and highlights the therapeutic potential of targeting micropeptides for myocardial infarction.
Authors
Youchen Yan, Tingting Zhang, Xin He, Tailai Du, Gang Dai, Xingfeng Xu, Zhuohui chen, Jialing Wu, Huimin Zhou, Yazhi Peng, Yan Li, Chen Liu, Xinxue Liao, Yugang Dong, Jing-song Ou, Zhan-Peng Huang
Citation Information: JCI Insight. 2025;10(5):e177999. https://doi.org/10.1172/jci.insight.177999.
Abstract
Neurofilament accumulation is associated with many neurodegenerative diseases, but it is the primary pathology in giant axonal neuropathy (GAN). This childhood-onset autosomal recessive disease is caused by loss-of-function mutations in gigaxonin, the E3 adaptor protein that enables neurofilament degradation. Using a combination of genetic and RNA interference approaches, we found that dorsal root ganglia from mice lacking gigaxonin have impaired autophagy and lysosomal degradation through 2 mechanisms. First, neurofilament accumulations interfere with the distribution of autophagic organelles, impairing their maturation and fusion with lysosomes. Second, the accumulations attract the chaperone 14-3-3, which is responsible for the proper localization of the key autophagy regulator transcription factor EB (TFEB). We propose that this dual disruption of autophagy contributes to the pathogenesis of other neurodegenerative diseases involving neurofilament accumulations.
Authors
Jean-Michel Paumier, James Zewe, Chiranjit Panja, Melissa R. Pergande, Meghana Venkatesan, Eitan Israeli, Shikha Prasad, Natasha Snider, Jeffrey N. Savas, Puneet Opal
Citation Information: JCI Insight. 2025;10(5):e186409. https://doi.org/10.1172/jci.insight.186409.
Abstract
High-grade serous ovarian cancer (HGSOC) is the most prevalent and aggressive histological subtype of ovarian cancer and often presents with metastatic disease. The drivers of metastasis in HGSOC remain enigmatic. APOBEC3A (A3A), an enzyme that generates mutations across various cancers, has been proposed as a mediator of tumor heterogeneity and disease progression. However, the role of A3A in HGSOC has not been explored. We observed an association between high levels of APOBEC3-mediated mutagenesis and poor overall survival in primary HGSOC. We experimentally addressed this correlation by modeling A3A expression in HGSOC, and this resulted in increased metastatic behavior of HGSOC cells in culture and distant metastatic spread in vivo, which was dependent on catalytic activity of A3A. A3A activity in both primary and cultured HGSOC cells yielded consistent alterations in expression of epithelial-mesenchymal transition (EMT) genes resulting in hybrid EMT and mesenchymal signatures, providing a mechanism for their increased metastatic potential. Inhibition of key EMT factors TWIST1 and IL-6 resulted in mitigation of A3A-dependent metastatic phenotypes. Our findings define the prevalence of A3A mutagenesis in HGSOC and implicate A3A as a driver of HGSOC metastasis via EMT, underscoring its clinical relevance as a potential prognostic biomarker. Our study lays the groundwork for the development of targeted therapies aimed at mitigating the deleterious effect of A3A-driven EMT in HGSOC.
Authors
Jessica M. Devenport, Thi Tran, Brooke R. Harris, Dylan Fingerman, Rachel A. DeWeerd, Lojain H. Elkhidir, Danielle LaVigne, Katherine Fuh, Lulu Sun, Jeffrey J. Bednarski, Ronny Drapkin, Mary M. Mullen, Abby M. Green
Citation Information: JCI Insight. 2025;10(5):e186344. https://doi.org/10.1172/jci.insight.186344.
Abstract
Glioblastoma (GBM) is the most lethal brain cancer, with GBM stem cells (GSCs) driving therapeutic resistance and recurrence. Targeting GSCs offers a promising strategy for preventing tumor relapse and improving outcomes. We identify SUV39H1, a histone-3, lysine-9 methyltransferase, as critical for GSC maintenance and GBM progression. SUV39H1 is upregulated in GBM compared with normal brain tissues, with single-cell RNA-seq showing its expression predominantly in GSCs due to super-enhancer–mediated activation. Knockdown of SUV39H1 in GSCs impaired their proliferation and stemness. Whole-cell RNA-seq analysis revealed that SUV39H1 regulates G2/M cell cycle progression, stem cell maintenance, and cell death pathways in GSCs. By integrating the RNA-seq data with ATAC-seq data, we further demonstrated that knockdown of SUV39H1 altered chromatin accessibility in key genes associated with these pathways. Chaetocin, an SUV39H1 inhibitor, mimics the effects of SUV39H1 knockdown, reducing GSC stemness and sensitizing cells to temozolomide, a standard GBM chemotherapy. In a patient-derived xenograft model, targeting SUV39H1 inhibits GSC-driven tumor growth. Clinically, high SUV39H1 expression correlates with poor glioma prognosis, supporting its relevance as a therapeutic target. This study identifies SUV39H1 as a crucial regulator of GSC maintenance and a promising therapeutic target to improve GBM treatment and patient outcomes.
Authors
Chunying Li, Qiqi Xie, Sugata Ghosh, Bihui Cao, Yuanning Du, Giau V. Vo, Timothy Y. Huang, Charles Spruck, Richard L. Carpenter, Y. Alan Wang, Q. Richard Lu, Kenneth P. Nephew, Jia Shen
Abstract
Intervertebral disc degeneration (IDD) is associated with low back pain, a leading cause of disability worldwide. Fibrosis of nucleus pulposus (NP) is a principal component of IDD, featuring an accumulation of myofibroblast-like cells. Previous study indicated matrix metalloproteinase 12 (MMP12) expression is upregulated in IDD but its role remains largely unexplored. We here showed that TGF-β1 could promote myofibroblast-like differentiation of human NP cells along with an induction of MMP12 expression. Intriguingly, MMP12 knockdown not only ameliorated the myofibroblastic phenotype but also increased chondrogenic marker expression. Transcriptome analysis revealed that the MMP12-mediated acquisition of myofibroblast phenotype was coupled to processes related to fibroblast activation and osteogenesis and pathways mediated by MAPK and Wnt signaling. Injury induced mouse IDD showed NP fibrosis with marked increase of collagen deposition and αSMA-expressing cells. In contrast, MMP12 knockout mice exhibited largely reduced collagen I and III but increased collagen II and aggrecan deposition, indicating an inhibition of NP fibrosis along with an enhanced cartilaginous matrix remodeling. Consistently, an increase of SOX9+/CNMD+ but decrease of αSMA+ NP cells was found in the knockout. Altogether, our findings suggest a pivotal role of MMP12 in myofibroblast generation, thereby regulating NP fibrosis in IDD.
Authors
Yi Sun, Wai Kit Tam, Manyu Zhu, Qiuji Lu, Mengqi Yu, Yuching Hsu, Peng Chen, Peng Zhang, Minmin Lyu, Yongcan Huang, Zhaomin Zheng, Xintao Zhang, Victor Y. Leung
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