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Abstract
Immune evasion is a major obstacle ahead of pancreatic cancer therapy. Recent data implicate pro-inflammatory macrophages in the progression of pancreatic ductal adenocarcinoma (PDAC) and its therapeutic response. However, whether or which of the pro-inflammatory macrophage subtypes play a crucial role in the immune escape of PDAC remains unclear. Here we identify a population of CD138+ tumor-associated macrophages (TAMs), characterized by their pro-inflammatory and neutrophil-chemotactic activity, which undergo significant expansion in both PDAC patients and mouse models. These cells are elicited by a local synergy between IL-34-syndecan-1 and PGE2-EP2 signaling and are associated with immune evasion and poor clinical outcomes in patients, while also promoting immune escape and disease progression in mouse models. Mechanistically, CD138+ TAMs establish a feedforward loop with immunosuppressive Siglec-F+ neutrophils, which exhibit elevated PGE2 expression, via the secretion of Saa3 and Cxcl1. Targeting CD138+ TAMs by disrupting IL-34-syndecan-1 signaling with anti-IL-34 neutralizing antibodies significantly suppresses PDAC progression, especially when combined with anti-PD-1 antibodies. Together, our study elucidates a CD138+ TAM-Siglec-F+ neutrophil axis that drives immune escape in PDAC and proposes a therapeutic strategy that integrates IL-34-syndecan-1 signaling blockade with anti-PD-1 immunotherapy for the treatment of PDAC.
Authors
Chao Wang, Qi Zhang, Jinyan Huang, Fangyu Lin, Danyang Zhao, Youling Mu, Junshuo Tong, Jinping Li, Yingjiqiong Liang, Tao Zeng, Fukang Shi, Hang Shen, Tingting Lu, Tingbo Liang
Abstract
Lysine-specific demethylase 1 (LSD1; KDM1A) orchestrates context-dependent chromatin programs, yet its role in epithelial immunity remains largely unknown. Here, we identify LSD1 as a central brake on retinoid- and AP-1–driven enhancer activation in epidermis and demonstrate that its inhibition induces anti-tumor immunity. While epidermal LSD1 is required during development, acute loss or topical inhibition in adult skin is tolerated and triggers coordinated expression of retinoic acid signaling, lipid remodeling, and chemokine induction pathways. CUT&RUN profiling reveals that LSD1 occupies enhancer regions enriched for AP-1 motifs at retinoid metabolism, lipid homeostasis, and immune genes. LSD1 loss increases H3K4me1/2 and gene activation at these sites, licensing a poised AP-1–retinoid program. Single-cell spatial analyses show that discrete keratinocyte subsets initiate retinoid signaling to recruit dendritic cells and activate CD4+ T cell responses. Topical LSD1 inhibition suppresses cutaneous squamous cell carcinoma in two models while amplifying keratinocyte–immune crosstalk. Functional perturbations reveal that retinoid signaling partially contributes, whereas CD4+ T cells are essential for tumor control. These findings define LSD1 as a master repressor of epithelial immune competence and nominate LSD1 inhibition as a therapeutic strategy to activate retinoid–AP-1 enhancer circuits and drive CD4-dependent tumor immunity in skin cancer.
Authors
Nina Kuprasertkul, Alyssa F. Moore, Carina A. D'souza, Julia Chini, Eun-Kyung Ko, Sijia Huang, Shuo Zhang, Ashley S. Anderson, Shaun Egolf, Laura V. Pinheiro, Alison Jaccard, Claudia T. Magahis, Lydia Bao, Yann Aubert, Cyria R. Olingou, Stephen M. Prouty, Donna Brennan-Crispi, David A. Hill, John T. Seykora, Kathryn E. Wellen, Brian C. Capell
Abstract
Obesity-linked steatosis is a significant risk factor for hepatocellular carcinoma (HCC); however, the molecular mechanisms underlying the transition from Metabolic dysfunction-associated steatotic liver disease (MASLD) to HCC remains unclear. We explored the role of the endoplasmic reticulum (ER)-associated protein NgBR, an essential component of the cis-prenyltransferases (cis-PTase) enzyme, in chronic liver disease. Hepatocyte-specific NgBR deletion in mice (N-LKO) intensifies triacylglycerol (TAG) accumulation, inflammatory responses, ER/oxidative stress, and fibrosis, ultimately resulting in HCC development with 100% penetrance after four months on a high-fat diet. Similarly, liver-specific knockout of DHDDS (D-LKO) NgBR’s cis-PTase partner and a knock-in model carrying a human NgBR mutation that impairs cis-PTase activity developed HCC under high-fat diet conditions, although with lower penetrance. Single cell transcriptomic atlas from affected livers provides a detailed molecular analysis of the transition from liver pathophysiology to HCC development. Mechanistically, NgBR deficiency promotes excessive hepatic TAG accumulation by enhancing lipid uptake and impairing very-low-density lipoprotein (VLDL) secretion. Importantly, pharmacological inhibition of diacylglycerol acyltransferase-2 (DGAT2), a key enzyme in TAG synthesis, abrogates diet-induced liver damage and HCC burden in N-LKO mice. Overall, our findings establish cis-PTase as a critical suppressor of MASLD-HCC conversion and suggest DGAT2 inhibition may serve as a promising therapeutic approach to delay HCC formation in advanced metabolic dysfunction-associated steatohepatitis (MASH).
Authors
Abhishek K. Singh, Balkrishna Chaube, Kathryn M. Citrin, Joseph Fowler, Sungwoon Lee, Jonatas Catarino, James Knight, Sarah C. Lowery, Sonal Shree, Keira E. Mahoney, Nabil E. Boutagy, Inmaculada Ruz-Maldonado, Kathy Harry, Marya Shanabrough, Trenton T. Ross, Stacy A. Malaker, Yajaira Suárez, Carlos Fernández-Hernando, Kariona A. Grabińska, William C. Sessa
Abstract
BACKGROUND. Immune checkpoint inhibitors (ICIs) targeting the programmed cell death-1 axis have revolutionized metastatic non–small cell lung cancer (mNSCLC) treatment. However, disease progression remains a concern, and the role of the complex tumor microenvironment (TME) in treatment failure is not fully understood. METHODS. In this biomarker study involving 103 patients with mNSCLC—including 81 patients who received ICI treatment—we evaluated the association between heterogeneous immune cell subsets and ICI efficacy through single-cell spatial profiling of pretreatment tumor tissue, using a 29-marker multiplex immunohistochemistry platform built for in-depth dissection of the TME. RESULTS. Among various types of intratumoral lymphocytes including T-helper 1 cells, regulatory T cells, and natural killer cells, only CD8+ T cells (TILs) were associated with ICI efficacy. Computational tissue segmentation underscored the importance of direct physical interactions between CD8+ TILs and cancer cells for ICI efficacy. TIL phenotyping identified CD39/CD103/Ki-67 positivity as a hallmark of exhausted yet functional tumor-reactive CD8+ TILs. Immunosuppressive tumor-associated macrophages (TAMs) and cancer-associated fibroblasts were independent unfavorable adversaries. High CD73 expression on cancer cells was suggested to confer tolerance to ICI in EGFR/ALK-oncogene+ NSCLC, potentially through M2-TAM accumulation and aberrant angiogenesis. CONCLUSION. Our study delineates the clinical relevance of heterogeneous immune cell subsets in ICI-treated mNSCLC, aiding the development of targeted therapeutic strategies. TRIAL REGISTRATION. Not applicable because this is a retrospective study. FUNDING. Osaka Cancer Society, KANAE Foundation for the Promotion of Medical Science, SGH Foundation, and YOKOYAMA Foundation for Clinical Pharmacology.
Authors
Kohsuke Isomoto, Koji Haratani, Takahiro Tsujikawa, Shuta Tomida, Yusuke Makutani, Masayuki Takeda, Kimio Yonesaka, Kaoru Tanaka, Tsutomu Iwasa, Kazuko Sakai, Kazuto Nishio, Akihiko Ito, Kazuhiko Nakagawa, Hidetoshi Hayashi
Abstract
Huntington’s disease (HD) is a fatal neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and striatal neuron degeneration, primarily affecting medium spiny neurons (MSNs). Despite extensive research, the underlying metabolic vulnerabilities contributing to HD pathogenesis remain poorly understood. In this study, we employ RNA sequencing (RNA-seq) and metabolomics analyses to identify marked dysregulation of one-carbon metabolism in HD. We validate that SHMT2, a key mitochondrial enzyme in the mitochondrial one-carbon (mt-1C) pathway, is substantially downregulated in HD patient-derived iPSC-differentiated human striatal organoids (hSOs) and YAC128 mice. Functionally, pharmacological inhibition or genetic deletion of SHMT2 exacerbates mutant huntingtin (mHTT) aggregation, induces MSN degeneration in hSOs, and impairs motor function in WT mice. Conversely, SHMT2 overexpression attenuates MSN degeneration in HD-hSOs and improves motor performance in YAC128 mice. Mechanistically, SHMT2 deficiency leads to homocysteine (HCY) accumulation, which interacts with AARS1 and suppresses histone lactylation, thereby perturbing transcriptional regulation and associating with neurodegenerative phenotypes. Finally, we demonstrate that the HD clinical drug haloperidol modulates SHMT2 expression and restores histone lactylation, providing a pharmacological tool to probe SHMT2-dependent metabolic and epigenetic regulation in HD models. These findings highlight a metabolic-epigenetic axis as a promising therapeutic target for HD.
Authors
Mingqin Lu, Kexin Li, Shanshan Wu, Zhilong Zheng, Xinyue Li, Shengda Wang, Hanwen Yu, Chunyue Liu, Yueqing Jiang, Xueqin Song, Yan Liu, Xing Guo
Abstract
Pseudoxanthoma Elasticum (PXE) is a rare disease caused by loss of function of the gene Abcc6 and characterized by ectopic calcification of multiple tissues, but the physiological reasons underlying ectopic calcification in PXE remain unclear. In a murine model of Abcc6 deficient PXE where animals develop robust cardiac calcification after heart injury, we show the critical importance of the liver in mediating ectopic cardiac calcification. Tissue-specific deletion of Abcc6 in the liver, but not in the heart was sufficient to cause post-injury cardiac calcification. Metabolomics and gene expression demonstrated deficiencies in nucleotide metabolism, cellular energetics and defects in cellular respiration, underlying ectopic calcification in PXE. Functional abnormalities in cellular respiration in the injured heart were similar in globally or liver-specific Abcc6-deficient animals demonstrating that hepatic Abcc6 expression regulates cellular respiration in the injured heart. We show that ectopic calcification in PXE is primarily dystrophic and treatment with clodronate or etidronate, that prevent the growth of calcium hydroxyapatite mineralization, was sufficient to rescue the phenotype of ectopic cardiac calcification in Abcc6-deficient states. Taken together, these observations highlight the role of the liver in regulating target tissue metabolic and mitochondrial function in causing ectopic calcification in Abcc6-deficient states.
Authors
Yijie Wang, Baiming Sun, Feiyang Ma, Bo Tao, Yiqian Gu, Zhiqiang Zhou, Jason Kim, Linlin Zhang, Zhihao Liu, Johanna ten Hoeve, Linsey Stiles, Lucia Fernandez-del-Rio, Calvin Pan, Orian Shirihai, Shili Xu, Thomas G. Graeber, Tamer Sallam, Matteo Pellegrini, Aldons J. Lusis, Arjun Deb
Abstract
BACKGROUND. Genetically engineered porcine livers are being developed as a bridge therapy for acute liver failure, providing detoxification and restoration of hepatic protein synthesis. Severe xenograft-associated severe thrombocytopenia remains a major limitation, and human mechanistic data are scarce. METHODS. Platelet kinetics were characterized in three human decedents undergoing extracorporeal cross-circulation with transgenic porcine livers. Platelet counts, transfusion requirements, and clearance patterns were assessed to distinguish consumption from marrow suppression or hypersplenism. Antibody- and complement-directed inhibitors were administered to test immune-mediated mechanisms. Mechanistic studies focused on porcine von Willebrand factor (pVWF)–dependent platelet activation, including ex vivo blockade with the anti-VWF nanobody caplacizumab, a vWF-directed antibody fragment that prevents vWF–platelet binding. A fourth decedent received caplacizumab during porcine liver perfusion. RESULTS. In all three initial cases, 80%–90% of circulating and transfused platelets were rapidly cleared, a pattern inconsistent with marrow suppression or hypersplenism. Antibody and complement inhibition failed to ameliorate thrombocytopenia. Recipient plasma induced robust pVWF-mediated platelet activation analogous to human Type IIb von Willebrand disease, which was completely abrogated ex vivo by caplacizumab. In a fourth decedent treated with caplacizumab, aberrant platelet activation was prevented, though full hematologic recovery was limited by pre-existing disseminated intravascular coagulation (DIC). CONCLUSIONS. Early thrombocytopenia during porcine liver xenotransplantation appears to be primarily driven by pVWF-mediated platelet activation rather than by classical immune or splenic mechanisms. Targeted VWF blockade with agents such as caplacizumab may mitigate platelet loss and improve the safety profile of extracorporeal porcine liver support in acute liver failure.
Authors
Liang Zhao, Sokratis A. Apostolidis, Aae Suzuki, Amrita Sarkar, Qian Guo, Felix Li, Alex Sagar, John I. Fallon, Mohamed A. Elzawahry, Syed Hussain Abbas, Leanne Lanieri, Kristen Getchell, Susan C. Low, Kim M. Olthoff, Emma E. Furth, Brendan J. Keating, Peter Friend, Mortimer Poncz, Abraham Shaked, Charles S. Abrams
Abstract
N6-methyladenosine (m6A) is a prevalent modification of mammalian mRNA. Increasing evidence has documented diverse roles of m6A in normal cell physiology and diseases. However, its functional role in erythropoiesis remains poorly understood. In this study, we found that deletion of Mettl3 using EpoR-Cre mouse led to microcytic/hypochromic anemia due to defective erythropoiesis along with impaired hemoglobin biosynthesis. Mechanically, Mettl3 deficiency disrupted nucleotide biosynthesis which induced DNA damage, leading to apoptosis of CFU-E cells and cell cycle arrest of erythroblasts. Integrated m6A sequencing and RNA-seq analysis along with biochemical studies identified Mthfd1, a key enzyme involved in nucleotide biosynthesis, as a Mettl3 direct target gene. Furthermore, deletion of Mettl3 led to decreased expression of Mthfd1 accompanied by a shortage of nucleotides dTMP and IMP in erythroid cells. Additionally, inhibition of METTL3 in human erythroid cells led to similar phenotypic and molecular changes, indicating conserved role of METTL3 in human and murine erythropoiesis. Our findings have identified a METTL3-m6A-MTHFD1 axis that plays a critical role in erythropoiesis by maintaining genome stability of erythroid cells via regulation of nucleotide biosynthesis. These findings provide important insights into the regulatory mechanisms of erythropoiesis and may have implications for underlying the mechanisms of anemias.
Authors
Linlin Zhang, Huizhi Zhao, Shihui Wang, Xueting Wu, Donghao Liu, Hengchao Zhang, Qianqian Yang, Ying Cheng, Xiuyun Wu, Jiangwei Zhao, Shijie Zhang, Huan Zhang, Haojian Zhang, Qiaozhen Kang, Lixiang Chen, Xiuli An, Xiaoli Qu
Abstract
Poly (ADP-ribose) polymerase inhibitors (PARPi) benefit homologous recombination-deficient (HRD) malignancies, yet resistance remains a major challenge. Leveraging specimens from a prospective neoadjuvant niraparib monotherapy trial in treatment-naïve high-grade serous ovarian cancer, we integrated PhenoCycler-Fusion spatial profiling, scRNA-seq, and multiplex immunohistochemistry to identify two therapeutic-modulated cellular neighborhoods: an IFN+ tumor cell-enriched niche that expands in resistant lesions and a tumor-associated macrophage (TAM)-enriched niche that persists but acquires enhanced immunosuppressive features. Mechanistically, sustained tumor cell-derived IFN induced osteopontin (SPP1) expression in TAMs via STAT signaling, creating immunosuppressive niches enriched in Tregs and myofibroblastic cancer-associated fibroblasts with intensified cell-cell interactions. SPP1 directly suppressed T cell signaling and effector function. High baseline SPP1+ cells predicted lower response rate (30.0% vs 76.2%, P = 0.021) and shorter progression-free survival (median 13.5 vs 28.3 months, P = 0.0006). In HRD mouse models, SPP1 blockade restored PARPi sensitivity, reversed acquired resistance, and enhanced T cell cytotoxicity—effects abrogated in immunodeficient mice, confirming immune dependence. These data establish a spatial IFN–SPP1 axis whereby persistent tumor cell IFN reprograms TAMs to promote PARPi resistance, position SPP1 as a key therapeutic target and prognostic biomarker for this therapy, and underscore therapeutic potential of microenvironment-targeted strategies to overcome PARPi resistance.
Authors
Dan Liu, Kangjia Tao, Cheng Xu, Wen Yang, Chujun Cai, Cui Feng, Kairong Xiong, Sisi Wu, Yaying Lin, Zikun Peng, Jianhua Chi, Wen Pan, Qing Zhong, Jiahao Liu, Xiong Li, Xingzhe Liu, Dongchen Zhou, Ding Ma, Guang-Nian Zhao, Yu Xia, Yong Fang, Qinglei Gao
Abstract
The mammalian brain relies primarily on glucose for its energy needs. Delivery of this nutrient to the brain is mediated by the glucose transporter-1 (GLUT1) protein. Low GLUT1 thwarts glucose entry into the brain, causing an energy crisis and, triggering, in one instance, the debilitating neurodevelopmental condition – GLUT1 deficiency syndrome (GLUT1DS). Current treatments for GLUT1DS are sub-optimal, as none address the root cause – low GLUT1 – of the condition. Levels of this transporter must respond rapidly to the brain’s changing energy requirements. This necessitates fine-tuning its expression. Here we describe a long-noncoding RNA (lncRNA) antisense to GLUT1 (SLC2A1) and show that it is involved in such regulation. Raising levels of the lncRNA had a concordant effect on GLUT1 in cultured human cells and transgenic mice; reducing levels elicited the opposite effect. Delivering the lncRNA to GLUT1DS model mice via viral vectors induced GLUT1 expression, enhancing brain glucose levels to mitigate disease. Direct delivery of such a lncRNA to combat disease has not been reported previously and constitutes, to our knowledge, a unique therapeutic paradigm. Moreover, considering the importance of maintaining homeostatic GLUT1 levels, calibrating transporter expression via the lncRNA could become broadly relevant to myriad conditions, including Alzheimer’s disease, wherein GLUT1 is perturbed.
Authors
Maoxue Tang, Sasa Teng, Yueqing Peng, Ashley Y. Kim, Yoon-Ra Her, Peter Canoll, Jeffrey N. Bruce, Phyllis L. Faust, Kailash Adhikari, Darryl C. De Vivo, Umrao R. Monani
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Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)