Research Article
Abstract
Abnormal expansions of the CAG trinucleotide repeat within specific gene exons give rise to polyglutamine (polyQ) diseases, a family of inherited disorders characterized by late-onset neurodegeneration. Recently, a new type of polyQ disease was identified and named spinocerebellar ataxia 51 (SCA51). SCA51 is caused by polyQ expansion in THAP domain containing 11 (THAP11), an essential transcription factor for brain development. The pathogenesis of SCA51, particularly how mutant THAP11 with polyQ expansion contributes to neuropathology, remains elusive. Our study of mouse and monkey brains revealed that THAP11 expression is subject to developmental regulation, showing enrichment in the cerebellum. However, knocking down endogenous THAP11 in adult mice did not affect neuronal survival. In contrast, expressing mutant THAP11 with polyQ expansion led to pronounced protein aggregation, cerebellar neurodegeneration, and motor deficits, indicating that gain-of-function mechanisms are central to SCA51 pathogenesis. We discovered activated microglia expressing triggering receptor expressed on myeloid cells 2 (TREM2) in the cerebellum of a newly developed SCA51 knockin mouse model. Mechanistically, mutant THAP11 enhanced the transcription of TREM2, leading to its upregulation. The loss of TREM2 or depletion of microglia mitigated neurodegeneration induced by mutant THAP11. Our study offers the first mechanistic insights to our knowledge into the pathogenesis of SCA51, highlighting the role of TREM2-mediated microglial activation in SCA51 neuropathology.
Authors
Eshu Ruan, Jingpan Lin, Zhao Chen, Qianai Sheng, Laiqiang Chen, Jiating He, Xuezhi Duan, Yiyang Qin, Tingting Xing, Sitong Yang, Mingtian Pan, Xiangyu Guo, Peng Yin, Xiao-Jiang Li, Hong Jiang, Shihua Li, Su Yang
Abstract
Mitral valve prolapse is often benign, but progression to mitral regurgitation may require invasive intervention and there is no specific medical therapy. An association of mitral valve prolapse with Marfan syndrome resulting from pathogenic FBN1 variants supports the use of hypomorphic fibrillin-1 mgR mice to investigate mechanisms and therapy for mitral valve disease. mgR mice developed severe myxomatous mitral valve degeneration with mitral regurgitation by 12 weeks of age. Persistent activation of TGF-β and mTOR signaling along with macrophage recruitment preceded histological changes at 4 weeks of age. Short-term mTOR inhibition with rapamycin from 4 to 5 weeks of age prevented TGF-β overactivity and leukocytic infiltrates, while long-term inhibition of mTOR or TGF-β signaling from 4 to 12 weeks of age rescued mitral valve leaflet degeneration. Transcriptomic analysis identified integrins as key receptors in signaling interactions, and serologic neutralization of integrin signaling or a chimeric integrin receptor altering signaling prevented mTOR activation. We confirmed increased mTOR signaling and a conserved transcriptome signature in human specimens of sporadic mitral valve prolapse. Thus, mTOR activation from abnormal integrin-dependent cell–matrix interactions drives TGF-β overactivity and myxomatous mitral valve degeneration, and mTOR inhibition may prevent disease progression of mitral valve prolapse.
Authors
Fu Gao, Qixin Chen, Makoto Mori, Sufang Li, Giovanni Ferrari, Markus Krane, Rong Fan, George Tellides, Yang Liu, Arnar Geirsson
Abstract
Graft endothelial cells (ECs) express donor alloantigens and encounter cytotoxic T lymphocytes (CTLs) but are generally spared during T cell–mediated rejection (TCMR), which predominantly affects epithelial structures. The mechanisms underlying this vascular immune privilege are unclear. Transcriptomics analyses and endothelial-mesenchymal transition assessments confirmed that the graft endothelium was preserved during TCMR. Coculture experiments revealed that endothelial and epithelial cells were equally susceptible to CTL-mediated lysis, ruling out cell-intrinsic protection. Intravital microscopy of murine kidney grafts and single-cell RNA-Seq of human renal allografts demonstrated that CTL interactions with ECs were transient compared with epithelial cells. This disparity was mediated by a chemotactic gradient produced by graft stromal cells, guiding CTLs away from ECs toward epithelial targets. In vitro, chemotaxis overrode T cell receptor–induced cytotoxicity, preventing endothelial damage. Finally, analysis of TCMR biopsies revealed that disruption of the chemotactic gradient correlated with endothelialitis lesions, linking its loss to vascular damage. These findings challenge the traditional view of cell-intrinsic immune privilege, proposing a cell-extrinsic mechanism, in which chemotaxis preserves graft vasculature during TCMR. This mechanism may have implications beyond transplantation, highlighting its role in maintaining vascular integrity across pathological conditions.
Authors
Thomas Barba, Martin Oberbarnscheidt, Gregory Franck, Chantal Gao, Sebastien This, Maud Rabeyrin, Candice Roufosse, Linda Moran, Alice Koenig, Virginie Mathias, Carole Saison, Valérie Dubois, Nicolas Pallet, Dany Anglicheau, Baptiste Lamarthée, Alexandre Hertig, Emmanuel Morelon, Arnaud Hot, Helena Paidassi, Thierry Defrance, Antonio Nicoletti, Jean-Paul Duong Van Huyen, Yi-Chung Xu-Dubois, Faddi G. Lakkis, Olivier Thaunat
Abstract
Lung cancer is the leading cause of cancer mortality among people with HIV (PWH), with increased incidence and poor outcomes. This study explored whether the tumor microenvironment (TME) of HIV-associated non–small cell lung cancer (NSCLC) limits tumor-specific immune responses. With a matched cohort of NSCLC samples from PWH and from people without HIV (PWOH), we used imaging mass cytometry, a linear mixed-effects model, and an artificial intelligence–based (AI-based) PageRank mathematical algorithm based on spectral graph theory to demonstrate that HIV-associated tumors have differential distribution of tumor-infiltrating CD8+ and CD4+ T cells, enriched for the expression of programmed cell death 1 (PD-1) and lymphocyte-activating gene 3 (LAG3), as well as activation and proliferation markers. We also demonstrate higher expression of immunoregulatory molecules (PD-L1, PD-L2, B7-H3, B7-H4, IDO1, and VISTA) among tumor-associated macrophages. Discrimination of cells between tumors from PWH versus those from PWOH was confirmed by spectral graph theory with 84.6% accuracy. Furthermore, we noted differences in spatial orientation of immune cells within the TME of PWH compared with PWOH. Additionally, cells from PWH, compared with those from PWOH, exhibited decreased tumor killing when exposed to HLA-matched NSCLC cell lines. In conclusion, our study demonstrates that the HIV-associated TME sustained a unique immune landscape, showing evidence of immune cells with enhanced immunoregulatory phenotypes and impaired antitumor responses, with implications for responses to immune checkpoint blocker therapies.
Authors
Shruti S. Desai, Syim Salahuddin, Ramsey Yusuf, Kishu Ranjan, Jianlei Gu, Lais Osmani, Ya-Wei Lin, Sameet Mehta, Ronan Talmon, Insoo Kang, Yuval Kluger, Hongyu Zhao, Kurt Schalper, Brinda Emu
Abstract
Acute-on-chronic liver failure (ACLF) is a leading cause of global liver-related mortality. Bacterial infection, especially in patients with decompensated cirrhosis, commonly triggers ACLF and is difficult to treat with antibiotics. Therefore, finding alternative strategies for preventing and managing bacterial infection is an urgent priority. Here, we observed that patients with bacterial infection and decompensated cirrhosis, as well as ACLF mice, exhibited lower fecal panose levels than uninfected controls. Megamonas funiformis, with 4α-glucanosyltransferase (4αGT) as a key enzyme for panose production, was identified as a potential panose producer. Animal experiments demonstrated that panose efficiently reduced liver injury and extended survival in ACLF mice by mitigating bacterial infection. Further results revealed that panose enhanced resistance to bacterial infection by inhibiting oxidative stress–induced gut barrier disruption, thereby limiting bacterial dissemination. Mechanistically, panose interacted with the solute carrier family 7 member 11 (SLC7A11, also known as xCT) protein to boost antioxidant glutathione levels in intestinal epithelial cells. These findings highlight panose’s potential in preventing bacterial infection, offering a valuable insight into mitigating ACLF progression.
Authors
Jiaxin Li, Shihao Xie, Meiling Chen, Changze Hong, Yuqi Chen, Fengyuan Lyu, Niexin Tang, Tianqi Chen, Lingyan Zhao, Weihao Zou, Hongjuan Peng, Jingna Bao, Peng Gu, Bernd Schnabl, Jinjun Chen, Peng Chen
Abstract
Nociception involves complex signaling, yet intrinsic mechanisms bidirectionally regulating this process remain unexplored. Here, we show that the fibroblast growth factor 13 (FGF13)/Nav1.7 protein–protein interaction (PPI) complex bidirectionally modulates nociception, and that the FGF13/Nav1.7 ratio is upregulated in type 2 diabetic neuropathy (T2DN). PW164, an FGF13/Nav1.7 channel C-terminal tail domain (CTD) PPI interface inhibitor, which reduces complex assembly, selectively suppressed Na+ currents sensitized by capsaicin-induced activation of TRPV1 channels in human induced pluripotent stem cell–derived (hIPSC-derived) sensory neurons and inhibited mechanical and thermal hyperalgesia in mice. FGF13 silencing mimics PW164 activity in culture and in vivo. Conversely, ZL192, an FGF13 ligand that stabilizes FGF13/Nav1.7 CTD assembly, sensitized Na+ currents in hIPSC-derived sensory neurons and exerted pronociceptive behavioral responses in mice. ZL192’s effects were abrogated by FGF13 silencing in culture and in vivo and recapitulated by FGF13 overexpression. In a model of T2DN, PW164 injection reduced mechanical hyperalgesia locally and contralaterally without systemic side effects. In donor-derived dorsal root ganglia neurons, FGF13 and Nav1.7 proteins colocalized, and the FGF13/Nav1.7 protein ratio was upregulated in patients with T2DN. Lastly, we found that SCN9A variant V1831F, associated with painless diabetic neuropathy, abolished PW164-directed modulation of the FGF13/Nav1.7 PPI interface. Thus, FGF13 is a rheostat of nociception and promising therapeutic target for diabetic neuropathy pain.
Authors
Aditya K. Singh, Matteo Bernabucci, Nolan M. Dvorak, Zahra Haghighijoo, Jessica Di Re, Nana A. Goode, Feni K. Kadakia, Laura A. Maile, Olumarotimi O. Folorunso, Paul A. Wadsworth, Cynthia M. Tapia, Pingyuan Wang, Jigong Wang, Haiying Chen, Yu Xue, Jully Singh, Kali Hankerd, Isaac J. Gamez, Makenna Kager, Vincent Truong, Patrick Walsh, Stephanie I. Shiers, Nishka Kuttanna, Hanyue Liao, Margherita Marchi, Erika Salvi, Ilaria D’Amato, Daniela D’Amico, Parsa Arman, Catharina G. Faber, Rayaz A. Malik, Marina de Tommaso, Dan Ziegler, Krishna Rajarathnam, Thomas A. Green, Peter M. Grace, Matthew R. Sapio, Michael J. Iadarola, Gregory D. Cuny, Diana S. Chow, Giuseppe Lauria Pinter, Steve Davidson, Dustin P. Green, Jun-Ho La, Jin Mo Chung, Jia Zhou, Theodore J. Price, Elizabeth Salisbury, Subo Yuan, Fernanda Laezza
Abstract
HIV infection accelerates biological aging, but the contribution of the host’s age to this process is unknown. We investigated the influence of SIV infection in macaques (SIVmac) on the risk of comorbidities and aging in young and old rhesus macaques (RMs) by assessing pathogenesis markers, DNA methylation–based epigenetic age (EA), and EA acceleration (EAA) in blood and tissues. Initially, upon SIV infection, the young RMs showed greater resilience to CD4+ T cell depletion, better control of T cell activation, hypercoagulation, and excessive inflammation, yet this resilience was progressively lost in the advanced stages of infection. During the late stages of infection, the young RMs, but not the aged ones, showed an increase in EA in PBMCs; also, EAA in the cerebellum and heart of young RMs was higher compared with old RMs. SIV infection was more pathogenic in aged animals in early stages, leading to a more rapid disease progression; however, accelerated aging mostly affected young animals, so that the levels of multiple key pathogenesis markers in the young RMs converged toward those specific to aged ones in the late stages of infection. We conclude that SIV infection–driven age acceleration is tissue specific, and that host age influences the susceptibility of different tissues to enhanced aging.
Authors
Anna J. Jasinska, Ranjit Sivanandham, Sindhuja Sivanandham, Cuiling Xu, Juozas Gordevicius, Milda Milčiūtė, Robert T. Brooke, Paola Sette, Tianyu He, Egidio Brocca-Cofano, Benjamin B. Policicchio, Krishna Nayak, Saharsh Talwar, Haritha Annapureddy, Dongzhu Ma, Ruy M. Ribeiro, Cristian Apetrei, Ivona Pandrea
Abstract
Thiopurines are anticancer agents used for the treatment of leukemia and autoimmune diseases. These purine analogs are characterized by a narrow therapeutic index because of the risk of myelosuppression. With the discovery of NUDIX hydrolase 15 (NUDT15) as a major modulator of thiopurine metabolism and toxicity, we sought to comprehensively examine all members of the NUDIX hydrolase family for their effect on the pharmacologic effects of thiopurine. By performing a NUDIX-targeted CRISPR/Cas9 screen in leukemia cells, we identified NUDT5, whose depletion led to drastic thiopurine resistance. NUDT5 deficiency resulted in a nearly complete depletion of active metabolites of thiopurine and the loss of thioguanine incorporation into DNA. Mechanistically, NUDT5 deletion resulted in substantial alteration in purine nucleotide biosynthesis, as determined by steady-state metabolomics profiling. Stable isotope tracing demonstrated that the loss of NUDT5 was linked to a marked suppression of the purine salvage pathway but with minimal effects on purine de novo synthesis. Finally, we comprehensively identified germline genetic variants in NUDT5 associated with thiopurine-induced myelosuppression in 582 children with acute lymphoblastic leukemia. Collectively, these results pointed to NUDT5 as a key regulator of the thiopurine response primarily through its effects on purine homeostasis, highlighting its potential to inform individualized thiopurine therapy.
Authors
Maud Maillard, Rina Nishii, Hieu S. Vu, Kashi R. Bhattarai, Wenjian Yang, Jing Li, Ute Hofmann, Daniel Savic, Smita Bhatia, Matthias Schwab, Min Ni, Jun J. Yang
Abstract
Nuclear size is crucial for cellular functions and often increases with malignancy. Irregular nuclei are linked to aggressive tumors, driven by genetic and epigenetic changes. However, the precise mechanisms controlling nuclear size are still not fully understood. In this study, we demonstrated that cancer-associated speckle-type POZ protein (SPOP) mutations enlarged nuclear size by reducing the protein level of lamin B2 (LMNB2), a key nuclear integrity protein. Mechanistically, SPOP bound to LMNB2 and promoted its mono-ubiquitination at lysine-484, which protected it from degradation by the E3 ubiquitin ligase WD repeat domain 26. SPOP mutations disrupted this process, leading to reduced LMNB2 levels and impaired nuclear envelope (NE) integrity. This compromised NE was more vulnerable to damage from farnesyltransferase inhibitors (FTIs), causing nuclear rupture in SPOP-mutant tumor cells. This study identified SPOP as a positive regulator of nuclear size; the findings suggest tumors with SPOP mutations may be vulnerable to FTI-based therapies.
Authors
Zixi Wang, Lei Li, Qi Ye, Yuzeshi Lei, Mingming Lu, Leihong Ye, Jialu Kang, Wenyue Huang, Shan Xu, Ke Wang, Jing Liu, Yang Gao, Chenji Wang, Jian Ma, Lei Li
Abstract
Brain metastasis is a major cause of breast cancer (BC) mortality, but the cellular and molecular mechanisms have not been fully elucidated. BC cells must breach the blood-brain barrier in order to colonize the brain. Here, we determined that integrin β3 (ITGB3) expression mediated by hypoxia-inducible factor 1 (HIF-1) plays a critical role in metastasis of BC cells to the brain. Hypoxia stimulated BC cell migration and invasion ex vivo and brain colonization in vivo. Knockdown of either HIF-1α or ITGB3 expression impaired brain colonization by human or mouse BC cells injected into the cardiac left ventricle. Exposure of BC cells to hypoxia increased expression of ITGB3 and its incorporation into small extracellular vesicles (EVs). EVs harvested from the conditioned medium of hypoxic BC cells showed increased retention in the brain after intracardiac injection that was HIF-1α and ITGB3 dependent. EVs from hypoxic BC cells showed binding to brain endothelial cells (ECs), leading to increased EC–BC cell interaction, increased vascular endothelial growth factor receptor 2 signaling, increased EC permeability, and increased transendothelial migration of BC cells. Taken together, our studies implicate HIF-1–stimulated production of ITGB3+ EVs as a key mechanism by which hypoxia promotes BC brain metastasis.
Authors
Yongkang Yang, Chelsey Chen, Yajing Lyu, Olesia Gololobova, Xin Guo, Tina Yi-Ting Huang, Vijay Ramu, Varen Talwar, Elizabeth E. Wicks, Shaima Salman, Daiana Drehmer, Dominic Dordai, Qiaozhu Zuo, Kenneth W. Witwer, Kathleen L. Gabrielson, Gregg L. Semenza
No posts were found with this tag.
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)