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Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) are leading causes of cirrhosis and hepatocellular carcinoma. Defects in autophagy contribute to the development of MASLD, however, the role of the Unc-51-like autophagy-activating kinase 1 (ULK1) in the pathophysiology of MASLD remains unclear. Herein, we show that ULK1, a serine/threonine kinase and core autophagy protein, is significantly repressed in human MASH livers, and that hepatocyte-specific loss of ULK1, unexpectedly, promotes hepatic steatosis and progression to liver fibrosis, without affecting basal autophagy flux. Phospho-proteomics identified the transcriptional coactivator NCOA3 as a downstream phospho-target of ULK1. Mechanistically, ULK1 phosphorylates NCOA3 to repress its transcriptional activity and restrain the CREB/CBP-mediated de novo lipogenic program. Accordingly, a phosphorylation-deficient NCOA3 mutant drives CREB/CBP-mediated lipogenesis, whereas genetic or pharmacological NCOA3 inhibition prevents steatosis, hepatic inflammation, and profibrotic signaling. Hence, ULK1-mediated NCOA3 phosphorylation is a fundamental and druggable checkpoint against the entire MASLD spectrum.
Authors
Young Do Koo, Romilia Tatiana Castillo, Asha Sukumaran Nair, Michael Garneau, Chad Gochee, Zachary V. Campbell, Tashya Shreyas Vakil, Jua Ha, Alex Marti, Jamie Soto, Debajyoti Das, Nuria Martinez-Lopez, Shipra Sharma, Yennifer Delgado, Callie Phung, Immy A. Ashley, Edmund D. Kapelczak, Rashel Jacobo, Eric T. Weatherford, Dao-Fu Dai, Jihane N. Benhammou, Andrea G. Marshall, Antentor Hinton Jr, Ling Yang, Renata O. Pereira, Tara TeSlaa, Mehdi Bouhaddou, Rajat Singh, E. Dale Abel
Abstract
Early initiation of antiretroviral therapy (ART) in perinatally HIV-infected children significantly limits the establishment of the viral reservoir. However, the long-term impact of this intervention remains unclear. We measured the frequency of inducible, translation-competent, and replication-competent proviruses in samples from 62 children who initiated ART early (median 9.9 weeks) and remained virally suppressed for up to 9.9 years. Only a small fraction of HIV genomes produced HIV transcripts (1.8%), viral proteins (<0.9%) or infectious virions (<0.05%). Accordingly, replication-competent virus was detected in only 15% of the participants. Despite the predominance of naïve cells in pediatric blood, most proviruses were detected in memory CD4+ T cells, especially central memory cells (contribution 41%). Longitudinal analysis revealed a biphasic decay in HIV DNA: an initial decline followed by long-term stability, which was associated with extensive expansions of infected T-cell clones. In contrast, inducible proviruses declined continuously and became undetectable in most children after five years. Near full-length sequencing of 1,305 HIV genomes revealed a dramatic reduction in genetically intact proviruses, from 40% pre-ART to 0.3% after 7 years of ART. Together, these findings suggest that the intact viral reservoir rapidly decays in early-treated children, offering critical insights for pediatric HIV cure strategies.
Authors
Marta Massanella, Caroline Dufour, Amélie Pagliuzza, Audrée Lemieux, Corentin Richard, Jintanat Ananworanich, Louise Leyre, Thidarat Jupimai, Supranee Buranapraditkun, Rapisa Nantanee, Julie L. Mitchell, Panadda Sawangsinth, Mark de Souza, Piyarat Suntarattiwong, Suparat Kanjanavanit, Pope Kosalaraksa, Thitiporn Borkird, Witaya Petdachai, Kulkanya Chokephaibulkit, Lydie Trautmann, Rémi Fromentin, Thanyawee Puthanakit, Nicolas Chomont
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging arboviral and zoonotic bunyavirus. CCHFV can infect livestock, wild animals, and humans. Here we report the isolation of a panel of monoclonal antibodies (mAbs) from the B cells of an immune individual following a natural nosocomial infection. We determined that the panel comprised antibodies that bound to two glycoproteins: 1) the carboxy-terminal glycoprotein (Gc) that serves as the fusion protein and 2) the glycoprotein 38 (GP38). By antibody variable gene analysis, we identified genetic diversity in the B cell response to CCHFV within a single donor for both Gc- and GP38-specific responses. Protection against most bunyavirus-associated diseases is mediated principally by neutralizing antibodies, but here, we found that neutralization activity was not associated with protection. Gc-specific antibodies to diverse antigenic sites neutralized only weakly and did not protect against heterologous virus challenge. GP38-specific antibodies bound to two dominant antigenic sites on the glycoprotein. Although GP38-specific antibodies did not neutralize the virus, one mediated protection against heterologous virus challenge in an experimental model of infection in mice primarily by complement-mediated activity. These studies support the model of development of CCHFV countermeasures that induce protection against GP38 in vivo.
Authors
Nathaniel S. Chapman, Viktoriya Borisevich, Nurgun Kose, Luke Myers, Stephen Priest, Éric Bergeron, Elena Trigo Esteban, María Paz Sanchez-Seco, Jose Melero, Thomas Geisbert, Robert W. Cross, James E. Crowe Jr.
Abstract
Cilia are cellular organelles extruding from the surface of various cell types, serving either sensory or motile functions. Retinitis pigmentosa GTPase regulator (RPGR) variants affect both photoreceptor sensory cilia and airway motile cilia, leading to retinitis pigmentosa (RP) and primary ciliary dyskinesia (PCD), respectively. Not all patients develop PCD, and it remains unclear which RPGR variants predispose patients to PCD. Here, we leverage 2D organoids, super-resolution microscopy, and live-cell imaging to characterize the multiciliated cells (MCCs) from patients with different RPGR variants and CRISPR-modified RPGR KO MCCs. We demonstrate that MCCs with RPGR variants have reduced ciliation, shorter cilia, impaired cilia beat, or cilia beat incoordination, potentially resulting in compromised mucociliary clearance and lung diseases. Moreover, we show that RPGR regulates motile cilia through interfering with F-actin dynamics, evidenced by the undissolved F-actin meshwork in RPGR-deficient MCCs, and the defects can be ameliorated with either Latrunculin A or Y27632 treatment. Though PCD was observed only in patients with variants that affect both isoforms, patients with RPGRORF15 variants also showed cilia and airway anomalies. All RPGR variants affect motile cilia one way or another, and the mechanisms involve the accumulation of apical F-actin.
Authors
Yang Wu, Erika Tavares, Binrun Liang, Wallace B Wee, Vito Mennella, Han-Chao Feng, Jiaying Cao, Pui Yee Wong, Jiayi Zheng, Mu He, Kirk AJ Stephenson, Liran Hanan Hochma, Janice Min Li, Nan-Peng Chen, Sharon D Dell, Elise Heon, ZHEN LIU
Abstract
BACKGROUND Proliferation is a key biological feature of cancer and in prostate cancer is modulated by androgen receptor (AR) signalling. Cohort studies have suggested that highly proliferative tumors respond poorly to androgen receptor pathway inhibitors (ARPIs). To clarify whether tumor proliferation interacts with treatment benefit from adding abiraterone to androgen deprivation therapy (ADT), we assessed the Ki-67 proliferation index in prostate core biopsies from participants enrolled in the STAMPEDE platform protocol. METHODS Proliferation was assessed by Ki67 immunohistochemistry on tumors from patients randomized in two sequential but non-overlapping (ie no shared controls) phase 3 trials of abiraterone or abiraterone and enzalutamide conducted in STAMPEDE (NCT00268476), with 14-year survival outcomes. A standardised unweighted global assessment method was used. Survival analyses used Cox proportional hazards models adjusted for established prognostic factors. Ki-67 was examined both continuously and dichotomised at the median. Sensitivity analyses excluded samples exposed to ADT. RESULTS Ki-67 was successfully scored on cancers from 1,605 patients. Higher Ki-67 was strongly prognostic for shorter overall survival across disease states. However, in metastatic patients treated with ADT plus abiraterone, the adverse prognostic impact of high Ki-67 was substantially attenuated (aHR=1.06 per 10-percentage-point increase), with a statistically-significant treatment-biomarker interaction (p<0.001) confirming highly proliferative tumors derived greater treatment benefit. No interaction was observed in non-metastatic disease. CONCLUSION Ki-67 is an independent prognostic biomarker in advanced prostate cancer. In metastatic disease, higher proliferation predicts greater sensitivity to abiraterone added to ADT, suggesting a potential biological vulnerability of rapidly cycling tumors to intensified AR pathway blockade. TRIAL REGISTRATION: NCT00268476
Authors
Larissa Mendes, Peter F. Dutey-Magni, Emily Grist, Ashwin Sachdeva, Sara Santos Vidal, Sharanpreet Lall, Marina A. Parry, Claire L. Amos, Nafisah B. Atako, Anna Wingate, Daniel Wetterskog, Matthew R. Sydes, Chris C. Parker, Noel Clarke, Christopher J. Sweeney, Mahesh KB Parmar, Louise C. Brown, Nicholas D. James, Daniel M. Berney, Gerhardt Attard
Abstract
Epigenetic dysregulation is associated with immune evasion and immune checkpoint blockade (ICB) resistance. Here, using in vivo CRISPR-Cas9 screens targeting epigenetic-related factors in mouse tumor models treated with ICB, we identified Chromobox 4 (CBX4) as a key negative regulator of immune tumor microenvironment. Single-cell RNA sequencing and spatial transcriptomics analyses of patients receiving neoadjuvant anti-PD-1 therapy revealed high CBX4 expression in both tumor cells and immunosuppressive tumor-associated macrophage subpopulations, with preferential accumulation in non-responders. Deficiency of CBX4 in macrophages or tumor cells, induced robust anti-tumor immunity, increased infiltration and cytotoxic activity of CD8+ T cells and NK cells, thereby heightening the sensitivity of ICB treatment. Mechanistically, CBX4 targeted H3K9me3 and H3K27me3-marked endogenous retroelements such as RLTR4-Mm-int. Loss of CBX4 derepressed retrotransposons, activating cytosolic RNA-sensing pathways and triggering type I interferon response, ultimately leading to robust inflamed TME. Moreover, we uncovered a negative correlation between CBX4 expression and immune responses, retrotransposon levels as well as the prognosis of patients with hepatocellular carcinoma (HCC) undergoing ICB therapy. Our study establishes CBX4 as an epigenetic immune checkpoint through the epigenetic silencing of retrotransposons, remodeling immune TME and thus providing a promising therapeutic target to enhance tumor immunogenicity and overcoming immunotherapy resistance.
Authors
Zhibo Ma, Wenlong Jia, Xi Zhou, Jing Liu, Qingwen Li, Ruizhi Chang, Shiqi Gu, Naonao Yuan, Zhishui Chen, Peixiang Lan
Abstract
VPS13A is an intracellular lipid transfer protein comprising over 3,000 amino acids. Mutations in human VPS13A cause VPS13A disease, a neurodegenerative disorder that affects movement and cognition. VPS13A forms a complex with the membrane protein XK to mediate ATP-induced phospholipid scrambling in the plasma membrane. Here, we established a mouse cell system expressing full-length mouse VPS13A and examined its interaction with XK. Mutational analysis revealed that VPS13A binds to XK through a C-terminal β-strand that interacts with a β-hairpin in the central region of XK, an interaction essential for scramblase activity. The XK paralog XKR2, which contains a similar β-hairpin structure, also associates with VPS13A and supports phospholipid scrambling. We analyzed ten mouse VPS13A variants corresponding to patient mutations and classified them into four groups: (1) L67P, I90K, and W2453R, which showed reduced expression; (2) A1091P and M3080R, which were normally expressed but lacked scramblase activity; (3) S1446P, Q2689H, Y2713C, and R3084H, which modestly impaired expression or activity; and (4) I2763R, which altered cell size, and disrupted ER independently of XK. These findings define the VPS13A–XK interaction interface, clarify the functional impact of disease-causing mutations, and reveal an unexpected gain-of-function mutation of a VPS13A variant.
Authors
Xing Lin, Yuta Ryoden, Chigure Suzuki, Hiroyuki Ishikawa, Takaharu Sakuragi, Yasuo Uchiyama, Shigekazu Nagata
Abstract
Resistance to HIF-2α inhibitors such as Belzutifan underscores the need to better understand how HIF-2α is transcriptionally regulated in clear cell renal cell carcinoma (ccRCC). Here, we uncover a cytokine-driven enhancer mechanism that sustains HIF-2α expression through the JAK1–STAT3 signaling pathway. Using a genome-wide CRISPR screen in VHL-deficient ccRCC cells, we identified SOCS3 as a key negative regulator of HIF-2α. Mechanistically, loss of SOCS3 activates JAK1–STAT3 signaling, leading to the recruitment of STAT3 to distal enhancers upstream of EPAS1 that physically loop to its promoter to drive HIF-2α transcription. This cytokine–enhancer circuit was recapitulated in ccRCC patient samples and functionally validated using CRISPR interference, which disrupted enhancer–promoter looping and reduced tumor growth in HIF-2α–dependent models. SOCS3 overexpression or pharmacologic inhibition of JAK1/STAT3 markedly suppressed HIF-2α expression and tumor progression both in vitro and in vivo. Unlike prior studies focusing on VHL/HIF occupancy–driven enhancer activation, this work defines a trans-acting cytokine–JAK1–STAT3 pathway that transcriptionally controls EPAS1. Together, these findings reveal a targetable enhancer mechanism that sustains HIF-2α expression and suggest that combined inhibition of JAK1/STAT3 and HIF-2α may overcome therapeutic resistance in kidney cancer.
Authors
Jun Fang, Jeremy M Simon, Tao Wang, Yunpeng Gao, Xianju Bi, Lianxin Hu, Chengheng Liao, Cheng Zhang, Yayoi Adachi, Jin Zhou, Hongyi Liu, Qian Liang, James A. Nathan, Ram Mani, James Brugarolas, Qing Zhang
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
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)