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Abstract
The lymphatic system plays a central role in lipid absorption by transporting triglyceride-rich particles called chylomicrons (CMs) from the small intestine to the systemic circulation. However, the molecular mechanism by which CMs get into the intestinal lymphatics is unknown. Here we demonstrated that GPR182, an atypical chemokine receptor in lymphatic endothelial cells, mediates dietary fat absorption. GPR182 knockout mice exhibit a selective increase in circulating high-density lipoproteins and are resistant to dietary-induced obesity. GPR182 ablation in mice leads to poor lipid absorption and thereby a delay in growth during development. GPR182 broadly interacts with and transports lipoproteins. Transmission electron microscopy analysis reveals that mechanistically, loss of GPR182 prevents CMs from entering the lacteal lumen of the small intestine. Consistent with this, GPR182 blockade with monoclonal antibodies protects mice from diet- induced obesity and treats existing obesity. Together, our study identifies GPR182 as a lipoprotein receptor that mediates dietary fat absorption and supports GPR182 blockade as a feasible approach to treat obesity and related disorders.
Authors
Zhiwei Sun, Robert J. Torphy, Emily N. Miller, Anza Darehshouri, Isaac Vigil, Taichi Terai, Eck Eleanor, Yi Sun, Yujie Guo, Dustin P. Fykstra, Elliott J. Yee, Junyi Hu, Ross M. Kedl, Erika L. Lasda, Jay R. Hesselberth, Julie A. Siegenthaler, Paul S. MacLean, Kimberley D. Bruce, Gwendalyn J. Randolph, Richard D. Schulick, Yuwen Zhu
Abstract
The peritoneal cavity contains a large population of GATA6-expressing large peritoneal macrophages (LPMs), known to support healing of intra-abdominal organs. In this study, we aimed to explore their full sphere of influence by examining their ability to perform wound healing at distant sites outside the cavity. In a mouse model combining a remote skin injury with peritoneal stimulation we observed a significant acceleration of skin wound healing in response to LPM activation. Tracking GATA6-expressing LPMs, we demonstrated that LPMs do not migrate to distant wound sites following peritoneal activation. Using parabiosis experiments and administration of activated peritoneal contents indicated an important role of molecules secreted by LPMs in remote skin wound healing. More specifically, proteomic and transcriptomic analyses identified fibronectin as a key factor produced by activated LPMs. In fact, depletion of LPMs or genetic knockout of fibronectin in myeloid cells eliminated the enhanced healing effect. These findings highlight the endocrine function of LPMs in systemic tissue repair, challenging the traditional perspective of plasma fibronectin being exclusively liver-derived. Our results suggest that LPMs, strategically positioned in the peritoneal cavity, serve as a source of circulating fibronectin, promoting matrix formation and accelerating wound healing at distant sites.
Authors
Lilian Salm, Simone N. Zwicky, Daniel Spari, Tural Yarahmadov, Marie Siwicki, Fernanda VS Castanheira, Jonas Zbinden, Deborah Stroka, Joel Zindel, Antoine Dufour, Paul Kubes, Guido Beldi
Abstract
Single-agent anti-PD-1 antibody is ineffective for pancreatic ductal adenocarcinoma (PDAC) due to its immunosuppressive tumor-microenvironment (TME). KRAS-mutations contribute to the inflammatory TME and therapeutic resistance by upregulating IL-8 via MAPK pathways. Thus, this study attempted to overcome the resistance to anti-PD-1 antibody by targeting downstream KRAS-effectors. The study found that the resistance to anti-PD-1 antibody can be overcome through MEK1/2-inhibition. The combination of anti-PD-1 antibody and MEK inhibitor displayed antitumor activity in Krasmut (mutated) KPC mouse tumors, but not KrasWT (wild-type) Panc02 tumors. The combination of anti-PD-1 antibody and MEK inhibitor induced recruitment of tumor-associated neutrophils (TANs) via CXCR2, an IL-8 receptor, and increased memory CD8+ T cells and IFNgamma production in treatment-sensitive tumors. However, larger tumors still resisted to the combination of anti-PD-1 antibody and MEK inhibitor likely due to hypoxia/necrosis-induced NETosis and associated paucity of CD8+ T cells. The subsequent addition of anti-CXCR2 antibody overcame this resistance by blocking TAN-infiltration to hypoxic/necrotic areas. Consistently, a risk-score based on the NETosis-MAPK signaling interaction is significantly associated with poorer survival in human PDACs. This study thus provides a new venue for overcoming resistance to strategies targeting KRAS signaling.
Authors
Brian Herbst, Alex B. Blair, Yiming Li, Elizabeth M. Jaffee, Lei Zheng
Abstract
Glioblastoma (GBM) is a highly aggressive brain tumor characterized by extensive crosstalk between glioblastoma stem cells (GSCs) and immunosuppressive microglia, with our previous work identifying CLOCK and TFPI2 as key regulators of this interaction. Here, we uncover a ‘symbiotic exclusivity’ pattern between CLOCK and TFPI2, showing that despite mutually exclusive amplifications, they sustain symbiotic regulatory interactions in GBM. The CLOCK-BMAL1 complex transcriptionally upregulates TFPI2, while TFPI2-driven hypoxia inducible factor 1 alpha (HIF1a) signaling activates nuclear factor kappa B (NF-kB) P65 to upregulate the CLOCK-BMAL1 complex, creating a positive feedback loop to promote stemness, immunosuppression, and tumor progression. Disrupting the CLOCK-TFPI2 interplay through dual inhibition of their downstream effectors reduces GSC stemness and immunosuppressive microglia, activates antitumor immunity, and synergizes with anti-PD1 therapy to achieve complete tumor regression in 50-62.5% of tumor-bearing mice. This study uncovers a promising therapeutic strategy for a broader subset of GBM patients with high expression of either CLOCK or TFPI2, and provides a framework for identifying 'symbiotic exclusivity' genes in cancer.
Authors
Fei Zhou, Lizhi Pang, Yang Liu, Fatima Khan, Peiwen Chen
Abstract
Understanding susceptibility factors of sepsis is crucial for early diagnosis and development of personalized treatment strategies. However, the genetic determinants for initiation and progression of sepsis remain unclear. Here, we showed that the expression levels of estrogen receptor (ER) β are significantly reduced in the peripheral blood of sepsis patients, which were negatively correlated with disease severity. The results from human samples and experimental animals demonstrated that ERβ deficiency enhances the body's susceptibility to sepsis by inducing macrophage pyroptosis, thereby impairing bacterial clearance. Mechanistically, ERβ deficiency enhanced fatty acid oxidation, increased acetyl-CoA levels, and promoted acetylation of stomatin-like protein 2 (Stoml2) at K221, leading to mitochondrial dysfunction and macrophage pyroptosis. Mutating the Stoml2 K221 site mitigated these effects and improved survival of septic mice. These findings suggest ERβ deficiency as a potential genetic factor in sepsis susceptibility.
Authors
Yanrong Zhu, Gang Li, Yilei Guo, Yue He, Wanyi Zhang, Lei Gao, Jing Zhang, Pengxiang Guo, Haochang Lin, Wenjie Zhang, Zhifeng Wei, Yufeng Xia, Yue Dai
Abstract
Airway mucus clearance from the lungs occurs by two widely recognized mechanisms: cilia-mediated clearance and high-velocity airflow-mediated cough clearance. However, a potentially important third mechanism of mucus clearance, referred to as cilia-independent gas-liquid transport (GLT), was proposed based on in vitro model systems to occur during normal tidal breathing, but has largely been overlooked. To investigate the role of tidal breathing airflow rates in mucus clearance, we conducted a series of in vitro and in vivo studies. An in vitro airway culture bead-tracking model demonstrated airflow-dependent mucus transport at tidal breathing flow rates. As with other modes of mucus clearance, GLT was critically dependent on mucus concentration. In vivo studies in cilial beat-deficient mice demonstrated that GLT-mediated mucus clearance occurs during tidal-breathing in the absence of cough, and the rate of GLT mucus clearance was dependent on breathing frequency and body orientation. These studies demonstrated that GLT represents a third mechanism of mucus clearance and likely represents a significant mode of clearance in persons with cilial dysfunction. These findings indicate that increasing breathing rates through exercise, using mucus rehydrating agents or mucolytics, or combining these approaches may restore clinically and physiologically meaningful airway clearance in these patients.
Authors
Siddharth K. Shenoy, Mark Gutay, Ian Brown, Troy D. Rogers, Kane Banner, Nico Olegario, Nicholas Griffin, Henry P. Goodell, Bryan Yoder, David S. Lalush, David A. Edwards, Richard C. Boucher, Barbara R. Grubb, Brian Button
Abstract
Gemcitabine-based chemotherapy is the standard treatment regime for advanced intrahepatic cholangiocarcinoma (iCCA), but the frequent presence of chemoresistance limits its efficacy. Here, we identified isocitrate dehydrogenase 1 (IDH1) as the crucial target that confers chemoresistance of iCCA to gemcitabine using a druggable CRISPR/Cas9 library. The positive association between IDH1 expression and chemoresistance was revealed in a gemcitabine-treated iCCA cohort and cell-based drug sensitivity assays. Utilizing patient-derived organoids, cell line-derived xenografts, and patient-derived xenografts, we demonstrated that IDH1 knockdown or IDH1 pharmacological inhibition facilitated gemcitabine efficacy in these pre-clinical iCCA models carrying wild-type IDH1 (wtIDH1). Mechanistically, wtIDH1 oxidizes isocitrate to generate α-ketoglutarate and NADPH, thereby coping with the oxidative stress induced by gemcitabine, maintaining cellular redox homeostasis, and ultimately leading to their chemoresistance to gemcitabine. Significantly, ivosidenib, the FDA-approved allosteric IDH1 inhibitor, demonstrated synergistic anti-tumor efficacy with gemcitabine in wtIDH1 pre-clinical iCCA models through boosting intracellular oxidative stress under physiological conditions. The low level of Mg2+, an ion that competitively hinders binding of ivosidenib on wtIDH1, in iCCA tumor microenvironment contributed to the expanded therapeutic window of ivosidenib in patients with iCCA. Our work revealed the potency of combining targeting IDH1 and chemotherapy against wtIDH1 iCCA and other tumors.
Authors
Xiuxian Li, Zhixiao Song, Shusheng Lin, Man Luo, Shaoru Liu, Yang Liu, Fapeng Zhang, Leibo Xu, Chao Liu, Honghua Zhang
Abstract
Cellular and molecular heterogeneity in the liver has been increasingly recognized to drive liver fibrosis progression, but the particular events that occur initially in response to liver injury and trigger the immune cell recruitment remain unclear. Here, we identify epigenetically aberrant liver sinusoidal endothelial cells (LSECs) as key players in this process. Mechanistically, the epigenetic readers like bromodomain-containing protein 4 (BRD4)-dependent super-enhancers (SEs) activate proinflammatory genes, including promyelocytic leukemia (PML). PML in turn binds BRD4 and amplifies proinflammatory angiocrine signaling through phase separation-dependent SE-activation via PML/BRD4 condensate formation. In mouse models, LSEC-specific depletion of the PML/BRD4 complex mitigates liver inflammation and fibrosis. Single-cell RNA-sequencing reveals that epigenetically aberrant LSECs exhibit a reprogrammed proinflammatory angiocrine landscape in mouse fibrotic livers. TIMP1+ LSECs promote the recruitment of CD63+ monocyte-derived macrophages (MoMFs) during liver fibrosis progression. Thereby, PML/BRD4 in LSECs governs inflammatory immune cell recruitment in liver fibrosis. Pharmacological BRD4 inhibition or epigenetic PML-SE repression alleviates liver inflammation and fibrosis. In conclusion, PML/BRD4-mediated SE activation via phase separation drives proinflammatory angiocrine signaling in LSECs, initiating the inflammatory cascade and subsequent immune cell recruitment during liver fibrosis.
Authors
Can Gan, Enjiang Lai, Yang Tai, Shuai Chen, Chong Zhao, Wenting Dai, Zhu Yang, Bei Li, Tian Lan, Yang Xiao, Yangkun Guo, Jiaxin Chen, Bo Wei, Zhaodi Che, Sheng Cao, Mengfei Liu, Frank Tacke, Chengwei Tang, Vijay H. Shah, Haopeng Yu, Fei Wang, Zhiyin Huang, Jinhang Gao
Abstract
High levels of L- and D-2-hydroxyglutarate (2HG), the reduced forms of α-ketoglutarate (αKG), are implicated in neurodevelopmental disorders and cancer by modulating αKG-dependent dioxygenases involved in histone, DNA and RNA demethylation. L-2HG dehydrogenase (L2HGDH) deficiency, a rare autosomal recessive inborn error of metabolism associated with systemic L-2HG elevation, causes progressive neurological disability and increased brain tumor risk of unclear mechanism. Using an isogenic, patient-derived induced pluripotent stem cell (iPSC) system, we examined the impact of L2HGDH deficiency on neural progenitor cell (NPC) function and neuronal differentiation. L2HGDH deficiency caused L-2HG accumulation, NPC hyperproliferation, increased clonogenicity, and defective neuronal differentiation in 2D cultures and cortical spheroids. Editing the L2HGDH locus to wild-type reversed these effects. Inhibiting glutaminase reduced L-2HG levels and induced neuronal differentiation. L-2HG-dependent inhibition of KDM5 histone demethylases led to widespread retention of H3K4me2/3, markers of active gene expression, with prominent enrichment at the MYC locus and elevated MYC expression across multiple neural cell types. Despite broadly altered histone methylation, genetically or pharmacologically normalizing MYC completely restored neuronal differentiation. These data indicated that a primary metabolic disturbance activated MYC to favor self-renewal and suppress neuronal lineage commitment.
Authors
Wen Gu, Xun Wang, Ashley Solmonson, Ling Cai, Yi Xiao, Alpaslan Tasdogan, Jordan Franklin, Yuannyu Zhang, Hua Zhang, Aundrea K. Westfall, Ashley Rowe, Hetali Trivedi, Brandon Faubert, Zheng Wu, Jessica Sudderth, Lauren G. Zacharias, Bushra Afroze, Ilya Bezprozvanny, Sunil Sudarshan, Feng Cai, Samuel K. McBrayer, Thomas P. Mathews, Ralph J. DeBerardinis
Abstract
Despite substantial progress in understanding the molecular pathology of Parkinson’s disease (PD), the underlying drivers of PD in many cases remain unknown. Here we investigate the role of RNA modification in PD, following observations of selective m6A hypomethylation in the substantia nigra (SN) of mouse PD models and dysregulated METTL3 and ALKBH5 expression in dopaminergic (DA) neurons from PD patients. We find preferential m6A deposition on transcripts of PD risk genes and a previously unreported heterozygous METTL3 p.K480R mutation in PD patients. Mettl3K480R/+ mice exhibit progressive METTL3 reduction and m6A hypomethylation in the SN, leading to progressive DA neuron loss, phospho-α-synuclein increase, and levodopa-responsive motor and non-motor deficits, mimicking PD progression. Dopamine transporter-specific METTL3 knockout mice recapitulate m6A hypomethylation, neurodegeneration and levodopa-responsive parkinsonism. Mechanistically, m6A deficiency disrupts mitochondrial biogenesis and function through regulating Tfam expression, while mitochondrial dysfunction reciprocally impairs m6A deposition, creating a pathogenic loop. Importantly, supplementation with S-adenosylmethionine (SAMe) enhances m6A modification, disrupts the pathogenic loop and alleviates parkinsonism in mouse models. Our findings reveal m6A dysregulation as an important contributor to PD pathogenesis, provide a valuable preclinical mouse model for PD progression, and highlight RNA methylation-targeted therapies as a promising strategy for PD intervention.
Authors
Sun Liu, Qihuan Ren, Guiling Mo, Zengguang Li, Huili Huang, Yuhao Zhou, Ziteng Miao, Xin Cao, Bilian Wu, Zhuoyu Xiao, Shihui Yu, Guangjin Wu, Linjian Xia, Jinru Cui, Junyuan Mo, Yuan Li, Laixin Xia, Juan Shen, Shan Xiao
Abstract
Stimulant medications are widely prescribed for attention deficit hyperactivity disorder (ADHD) and have significant abuse liability. Here we show that - consistent with clinical data - females exhibit enhanced behavioral sensitivity to stimulants and define sex- and hormone-dependent adaptations in the dopamine system that contribute to these effects. Single-nucleus RNA sequencing of ventral tegmental area dopamine neurons revealed that projections to the nucleus accumbens (NAc) core - compared to other projection populations - were a hub of sexually dimorphic gene expression, including transcripts regulating dopamine synthesis, and transport. These molecular differences coincided with enhanced dopamine release and clearance in females, particularly during phases of the estrous cycle when estradiol levels were high. The stimulants amphetamine (a releaser) and methylphenidate (a reuptake inhibitor) more effectively increased dopamine levels in females under certain conditions. However, amphetamine showed more robust hormone-sensitive regulation, with potency reduced by ovariectomy and restored by direct estradiol replacement in the NAc core. Together, the findings indicate that even within a drug class, drugs with different mechanisms of action can leverage different aspects of sexually dimorphic dopamine function. This distinction highlights that sex differences are not uniform but can be differentially sensitive to drug pharmacology.
Authors
Brooke A. Christensen, Jennifer Tat, Michael Z. Leonard, Soren D. Emerson, Shemuel Roberts, Eleanor B. Holmgren, Ainoa Konomi-Pilkati, Hannah B. Elam, Devan M. Gomez, Lin Zheng, Hye Jean Yoon, Sofia H. Lago, Abigail L. Carr, Lillian J. Brady, Maxime Chevée, Erin S. Calipari
Abstract
The dynamic assembly and regulation of the IκB kinase (IKK) complex in the NF-κB pathway are central to the pathogenesis and progression of inflammatory bowel disease (IBD). We recently reported that the transcription factor hematopoietically-expressed homeobox (HHEX) promotes colitis-associated colorectal cancer, but the potential role of HHEX in intestinal inflammation remains uncharacterized. Here, we found that HHEX is upregulated in inflamed colons in a colitis mouse model and in clinical IBD samples. HHEX overexpression increased inflammatory cytokine expression, and HHEX loss largely abrogated the inflammatory response in vitro and intestinal inflammation in vivo. Mechanistically, IKKα phosphorylates HHEX at S213 to stabilize HHEX in response to TNF-α by inhibiting the interaction of HHEX with the E3 ubiquitin ligase MID2 and subsequent K48-linked ubiquitination and protein degradation. Importantly, HHEX interacts with and stabilizes the IKKα/IKKβ complex via its N-terminal domain, thereby activating the NF-κB pathway and establishing a positive feedback loop that exacerbates intestinal inflammation. Our study reveals a transcription-independent function of HHEX in promoting IKK complex assembly and colitis, identifying HHEX as an IBD susceptibility gene and a potential target for IBD treatment.
Authors
Zhebin Hua, Weimin Xu, Wenjun Ding, Zhuoyue Fu, Yaosheng Wang, Yiqing Yang, Fangyuan Liu, Zhujiang Dai, Wenbo Tang, Weijun Ou, Wensong Ge, YingWei Chen, Zhongchuan Wang, Chen-Ying Liu, Peng Du
Abstract
This study investigated how chronic pelvic pain (CPP) develops using rhesus macaques with naturally occurring endometriosis and a multiple-lesion induction mouse model (MIM), as repeated retrograde menstruation is considered an underlying mechanism of endometriosis pathogenesis. MIM increased lesion numbers and elevated hypersensitivity. Elevated persistent glial cell activation was observed across multiple brain regions and/or spinal cords in MIM and rhesus macaques. Elevated TRPV1, SP, and CGRP expressions in the dorsal root ganglia (DRG) were persistent in MIM. MIM induced the severe disappearance of TIM4hi MHCIIlo residential macrophages and an influx of increased pro-inflammatory TIM4lo MHCIIhi macrophages in the peritoneal cavity. Cytokine levels were persistently elevated in MIM. Furthermore, dienogest (a synthetic progestin) and fingolimod (a selective immunosuppressor) reduced hyperalgesia and neuroinflammation. Our results indicate that recurrent retrograde menstruation can be a peripheral stimulus that induces nociceptive pain and creates a composite chronic inflammatory stimulus, leading to neuroinflammation and sensitization of the central nervous system. The circuits of neuroplasticity and stimulation of peripheral organs via a feedback loop of neuroinflammation may mediate widespread endometriosis-associated CPP. These findings in mice were further supported by results from the spontaneously developed advanced endometriosis in rhesus macaques via recurrent retrograde menstruation.
Authors
Madeleine E. Harvey, Mingxin Shi, Yeongseok Oh, Taylor M. Page, Debra A. Mitchell, Addie Luo, Ov D. Slayden, James A. MacLean, Anjali Sharma, Kanako Hayashi
Abstract
PRC2/EZH2 inhibitors (PRC2i/EZH2i) are promising for treatment of advanced cancers including metastatic prostate cancer. Here we show that PRC2i/EZH2i alone or in combination with AR inhibitors induce diverse cell state programs (CSP) (e.g., response to stress or interferon, MYC targets, stem cell, EMT and multiple developmental programs) which led to increased tumor cell invasion, metastasis and resistance to other drugs, in addition to modest suppression of tumor growth. In contrast to the current perception, our comprehensive, integrated genomics and epigenomics profiling of PDX and clinical tumors revealed that PRC2/EZH2 suppresses CSP genes through maintaining chromatin bivalency. Hyperactive Wnt/β-catenin signaling and inhibitors of PRC2/EZH2 and AR alter chromatin bivalency through antagonizing PRC2 and stimulating MLL2/KMT2B in a feedforward manner. Circadian rhythm regulator REV-ERBα unexpectedly reprograms β-catenin in promoting bivalency resolution and CSP gene expression. Dual targeting of Wnt/β-catenin and EZH2 diminishes diverse cell states through restoring bivalency and effectively block tumor growth. Our findings provide unexpected insights of chromatin bivalency and dysregulated circadian rhythm in control of cell state diversity and offer alternative therapeutic strategies targeting PRC2/EZH2 for advanced malignancies.
Authors
Yatian Yang, Xiong Zhang, Varadha Balaji Venkadakrishnan, Hongye Zou, Xingling Zheng, Shiyao Guo, Christopher Z. Chen, Alexander D. Borowsky, Eva Corey, Ronald M. Evans, Allen C. Gao, Marc A. Dall'Era, Amina Zoubeidi, Primo N. Lara, Hsing-Jien Kung, Xinbin Chen, Himisha Beltran, Hong-Wu Chen
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
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)