Cell biology
Abstract
Hepatocellular carcinoma (HCC) is heterogeneous, and hepatocyte plasticity is linked to poorer patient outcomes. A subset of human HCC harboring Tuberous Sclerosis Complex 1 (TSC1) mutations exhibits more aggressive behavior. TFEB is a master regulator of lysosomal biogenesis and cell fate. We analyzed human normal and HCC tissue arrays for TFEB and CK19 expression, as well as bulk and single-cell RNA-seq datasets from mouse and human HCC, to define TFEB-associated transcriptional programs. We performed biochemical, histological, metabolomic, and transcriptomic analyses in liver-specific Tsc1 knockout (L-Tsc1 KO) and L-Tsc1,Tfeb double KO (DKO) mice. Loss of hepatic Tsc1 led to increased phosphorylation of S6 and 4EBP1, with paradoxical increases in TFEB nuclear translocation and activation. L-Tsc1 KO mice showed increased hepatocyte plasticity, decreased HFN4α, increased YAP1 activation, and spontaneous HCC with increased SOX9 and CK19-positive biliary epithelial cell (BEC)-like cells at 8-12 months. Deletion of Tfeb dampened hepatic metabolic reprogramming and hepatocyte fate changes and inhibited tumor progression in L-Tsc1 KO mice. Increased TFEB activity was associated with increased YAP and SOX9 gene expression and high-grade malignant HCC in humans. These findings indicate that loss of hepatic TSC1 leads to non-canonical TFEB activation, promoting hepatocyte plasticity and tumor heterogeneity associated with high-grade malignancy in both mouse and human HCC.
Authors
Chen Zhang, Xiaojuan Chao, Sha Neisha Williams, Xiaoli Wei, Anthony DiGirolamo, Alisha Bajracharya, Lichun Ma, Ming Huang, Nicholas Dunn, Wanqing Liu, Kaito Ueda, Masayuki Sugimoto, Andrea Ballabio, Hong-Min Ni, Wen-Xing Ding
Abstract
Effective psychotherapeutic interventions for post-traumatic stress disorder (PTSD) rely on fear extinction to suppress maladaptive fear responses, yet their long-term efficacy is limited by high relapse rates. Notably, extinction involves not only fear inhibition but also affective engagement. However, whether and how internal affective components contribute to extinction retrieval and long-term persistence remain unclear. Here, we demonstrate that positive affective experiences arising during extinction govern the long-term persistence of extinction and resistance to spontaneous recovery. We identify a subpopulation of medial prefrontal cortex (mPFC) extinction neurons projecting to supramammillary nucleus glutamatergic (SuMGlu) neurons that encodes positive affective experience during extinction and selectively governs long-term extinction persistence. This ensemble is spatially, anatomically, and transcriptionally distinct from mPFC extinction neurons projecting to zona incerta somatostatin-expressing (ZISST) neurons, which primarily support extinction retrieval. Transcriptomic profiling reveals enrichment of sirtuin 1 (Sirt1) within SuM-projecting extinction ensembles, and bidirectional manipulation of SIRT1 alters extinction relapse vulnerability in a PTSD mouse model. These findings provide a cortical–hypothalamic framework incorporating molecular features that governs the long-term persistence of fear extinction and resistance to relapse through positive affective processes.
Authors
Ze-Jie Lin, Xin-Rong Wu, Ming-Yang Wei, Zheng-Kai Lao, Xiang Lan, Yan-Jiao Wu, Wei-Guang Li, Tian-Le Xu, Li-Na Huang, Xue Gu
Abstract
Authors
Zhichuan Zhu, Yusha Liu, Yu Deng, Zhijun Li, Albert S. Baldwin, Pengda Liu
Abstract
Resistance to CDK4/6 inhibitors (CDK4/6i) combined with endocrine therapy presents a major barrier to improving outcomes in ER+ breast cancer. We identified FADD phosphorylation at Ser194 (phospho-FADD) as a mediator of CDK4/6i resistance in the models examined. Phospho-FADD acted as a pseudosubstrate inhibitor of the APC/C-Cdh1 complex, promoting G1/S transition and bypassing the canonical CDK4/6-Rb-E2F pathway. This CDK4/6-independent pathway was associated with PI3K hyperactivation. Clinical relevance of this bypass pathway was supported by increased phospho-FADD and pAKT in 73% of paired patient biopsies at post-treatment recurrence, while the remaining cases exhibited high baseline phospho-FADD and pAKT with intrinsic non-response. Inhibition of FADD phosphorylation with the CK1α degrader DEG-77, or PI3K inhibition, restored CDK4/6i sensitivity in resistant cells. In CDK4/6i-refractory xenografts, CK1α degradation combined with CDK4/6i resulted in profound tumor regressions and increased progression-free survival compared with either single agent, including complete tumor regressions in 92% of tumors. These findings support CK1α-mediated FADD phosphorylation as a targetable resistance mechanism in a subset of CDK4/6i-resistant ER+/HER2– breast cancer.
Authors
Sahezeel Awadia, Elizabeth K. Ziemke, Nicole M. Curnutt, Emily Kirk, Julianne Thomas, Anna Zimmerman, Maya J. Mileski, Sundaresh Ram, Reine Abou Zeidane, Craig Galban, Christina M. Woo, Corey W. Speers, Judith Leopold, Alnawaz Rehemtulla
Abstract
When massive hepatic necrosis (MHN)-associated acute liver failure (ALF) occurs following severe damage, liver progenitor cells (LPCs) exit quiescence and enter differentiation programs during which they acquire hepatocyte-like functions. To date, how LPCs maintain quiescence under physiological conditions and orchestrate activation following MHN remains largely unknown. Here, we elucidate an essential role of TGF-β in regulating LPC quiescence and activation. Spatial transcriptomics and single-cell sequencing revealed that LPCs receive multiple signals, particularly TGF-β, HGF, and EGF from surrounding hepatic stellate cells and macrophages in patients and zebrafish with MHN-induced ALF. Physiologically, TGF-β inhibits LPC proliferation by blocking the G1-S phase transition, an effect that was reversed by Smad7 overexpression in a murine injury model. Intriguingly, extensive LPC proliferation was observed in ALF patients despite strong TGF-β-p-SMAD signaling. Immunostaining further revealed concurrent activation of HGF/MET, EGF/EGFR, and downstream STAT3/ERK pathways in LPCs. In vitro, HGF or EGF overcame TGF-β-mediated growth arrest and promoted LPC proliferation. Beyond acting as a mitogen, HGF additionally induced hepatocyte gene programs (e.g., Hnf4a, Hnf1a) in LPCs. Strikingly, TGF-β signaling was required for HGF-dependent hepatocyte gene induction, indicating a dual role in restraining LPC proliferation and promoting functional maturation. These findings position TGF-β as a context-dependent determinant of LPC activation and lineage specification during ALF.
Authors
Chenhao Tong, Tao Lin, Han Wang, Luyao Jiang, Xiaodong Yuan, Wenwu Luo, Minghan Zhou, Carolina De La Torre, Hui Liu, Chen Shao, Seddik Hammad, Hui Gao, Jiarong Xie, Lei Xu, Roman Liebe, Zuguang Gu, Matthias P. Ebert, Huiguo Ding, Steven Dooley, Hong-Lei Weng
Abstract
Gut microbiota-derived trimethylamine N-oxide (TMAO) plays a role in the pathogenesis of cardiovascular disease. The role of TMAO in the pathogenesis of atrial fibrillation (AF) remains uncertain. TMAO levels were quantified in plasma from serial subjects undergoing elective cardiac catheterizations (N=5090) and shown to independently associate with prevalent AF following adjustment for risk factors (TMAO adjusted odds ratio 1.7 [95% confidence interval 1.3-2.1]; P<0.01). Human cAMP response element modulator isoform IbΔC-X transgenic mice (CREM-IbΔC-X), a spontaneous mouse model of AF, supplemented with a TMAO diet developed AF sooner. C57BL/6J mice on and off a TMAO had more inducible AF via a transesophageal pacing study compared to chow controls. Dietary choline supplementation increased circulating TMAO levels and significantly accelerated AF onset in CREM-IbΔC-X mice (P<0.01). Iodomethylcholine (IMC), the gut microbial CutC/D inhibitor that suppresses choline→TMA(O) metabolic transformation, reduced circulating TMAO levels (P<0.0001) and choline induced AF onset (P<0.01). Cecal metagenomic analyses showed that choline supplementation induced changes in microbial communities associated with AF, while many of these changes were attenuated by IMC. Choline supplementation promoted overall adverse atrial remodeling with left atrial dilation. Optical mapping studies showed that mice supplemented with choline exhibited reduced conduction velocity, shortened action potential duration at 80% repolarization, and decreased wavelength. TMAO inhibits muscarinic receptor 2 resulting in autonomic dysfunction that promotes AF. In summary, the gut microbial metabolite TMAO, independently associated with AF risk in subjects, enhances AF in multiple AF mouse models via autonomic dysfunction, and is a therapeutic target for prevention of AF.
Authors
Selvam Arjunan, Isaiah Pemberton, Xinmin S. Li, Naseer Sangwan, Lydia Akino, Emmanuel Opoku, Dmitriy Verbovetskiy, Ina Nemet, Hyun Su Kim, Haruko Masumiya, Zeneng Wang, Joseph A. Lupica, Melissa Y. Tian, Karis Mao, Deepthi P. Mallela, Maradumane Mohan, Sarah Schumacher, Julie H. Rennison, Sathyamangla Prasad, Kenneth R. Laurita, Vamsi Chodisetty, Mina K. Chung, David R. Van Wagoner, John Barnard, Jonathan D. Smith, Oussama Wazni, Stanley L. Hazen, Robert A. Koeth
Abstract
Neddylation is highly activated in many human cancers and may serve as a therapeutic target for clinical treatment. However, it remains unclear regarding the role of neddylation in tumor angiogenesis. Here, we demonstrate that the neddylation E2 enzyme UBE2M is upregulated in tip cells and is essential for tumor vascular sprouting. We show that UBE2M-mediated neddylation of STAT1 enhances its phosphorylation and promotes the transcription of DLL4. This elevated DLL4 expression in tip cells activates Notch signaling in adjacent stalk cells, thereby maintaining the tip-stalk cell balance and ensuring organized vascular patterning. Consequently, endothelial-specific deletion of UBE2M reduces DLL4 expression, leading to excessive but non-productive sprouting due to uncontrolled tip cell formation and lack of stalk cell support, which ultimately suppresses tumor growth. Importantly, targeting endothelial neddylation potently sensitizes various tumors to anti-VEGF therapy. Together, our findings unveil UBE2M as a key regulator of angiogenic signaling and identify it as a promising anti-angiogenic target in cancer.
Authors
Xinyi Jiang, Jie Zhang, Li Zhou, Zonglin Li, Ningcong Sun, Xian Xu, Jisong Zhang, Yizhou Huang, Xue Zhang, Enguo Chen, Hongqiang Cheng, Yuehai Ke
Abstract
Efferocytosis, the clearance of apoptotic cells by macrophages, promotes tissue resolution. Efficient resolution requires efferocytosis-induced macrophage proliferation (EIMP) to expand pro-resolving macrophages. Here, we show that efferocytosis activates base excision repair (BER) to remove 8-OHdG from DNA, enabling EIMP. Mechanistically, efferocytosis promotes poly(ADP-ribose) polymerase-1 (PARP1) chromatin binding and PARylation to facilitate DNA repair complex assembly, and increases nuclear MTH1/NUDT1, which hydrolyzes 8-OHdG. Both processes require DNA-methyltransferase-3A (DNMT3A), which is activated during efferocytosis. Using a model where dexamethasone-induced thymocyte apoptosis triggers efferocytosis-mediated thymic repair, we showed that DNMT3A is required for increases in nuclear PARP1/MTH1, oxidized DNA suppression, EIMP in thymic macrophages, and thymic repair. We next studied a human-relevant model of atherosclerosis regression, where efferocytosis drives protective lesional fibrous cap thickening. We compared WT mice with a model of DNMT3A-clonal hematopoiesis (CH), in which loss-of-function DNMT3A mutations promote atherosclerotic disease. Atherosclerosis regression in WT mice led to decreased nuclear 8-OHdG and increases in nuclear PARP1/MTH1 and EIMP in lesional macrophages and fibrous cap thickening, all of which were impaired in DNMT3A-CH regression. These findings reveal that efferocytosis initiates a BER pathway to allow macrophage proliferation for tissue resolution, with possible therapeutic relevance to atherosclerosis regression and DNMT3A-CH.
Authors
Kleopatra Avrampou, Santosh R. Sukka, David Ngai, Patrick Ampomah, Xiaobo Wang, George Kuriakose, Jacob Glass, Bernhard Dorweiler, Hanna Winter, Lars Maegdefessel, Hanrui Zhang, Aaron Viny, Ira Tabas
Abstract
Hepatic stellate cell (HSC) activation can lead to liver fibrosis, for which there are no effective treatments. Aberrant cytoskeletal reorganization is a central driver of HSC activation. Non-muscle myosin II (NM II) is known to regulate cytoskeleton remodeling via its actin cross-linking and contractile properties. However, the molecular players controlling actomyosin assembly and contractility in HSCs during liver fibrosis remain poorly defined. Here, we identified integrin β-like 1 (ITGBL1) as a gatekeeper of HSC quiescence by negatively regulating actomyosin contractility-driven mechanotransduction in HSCs. ITGBL1 expression was markedly elevated in activated HSCs found in patient and mouse fibrotic livers. Unexpectedly, HSC-specific Itgbl1 deficiency worsened liver fibrosis, whereas ITGBL1 overexpression in HSCs limited it, suggesting a protective role for ITGBL1 against a pathogenic HSC activation. Multi-omics and functional analyses revealed that ITGBL1 impaired F-actin filament organization in HSCs by disrupting myosin heavy chain 9 (MYH9, also named NM II heavy chain A)-dependent actomyosin assembly. In line, HSC-specific Myh9 deficiency or silencing of Myh9 in HSCs alleviated liver fibrosis. Taken together, our findings unveil the ITGBL1-MYH9 interaction acts as a critical mechano-regulatory brake that maintains cytoskeletal equilibrium and mechanical homeostasis in HSCs, providing a promising therapeutic strategy to combat liver fibrosis.
Authors
Yixin Li, Yan Wang, Chenhao Tong, Xinghuan Fu, Ningning Ma, Yawen Hao, Zian Feng, Shijia Ling, Zequn Yin, Haodong Li, Shujun Ge, Siting Yang, Peng Xiao, Siyue Dong, Adrien Guillot, Yajun Duan, Yong He
Abstract
Methionine cycle plays critical roles in cell fate determination by shaping epigenetic landscape, yet its function in human erythropoiesis remains undefined. Here, we show that disruption of methionine metabolism by compromising key enzyme adenosylhomocysteinase (AHCY) reshapes H3K4me3 landscape, causing erythroid cell fate reprogramming. AHCY deficiency severely impaired erythroid differentiation and expansion, leading to the generation of non-erythroid lineage hematopoietic cells, including stem/progenitor cells and immune cells, as evidenced by single-cell RNA sequencing, Pseudo temporal analysis delineated a precise dedifferentiation trajectory, revealing erythroblasts transitioning back to MEPs and HSCs. Moreover, human hematopoietic system could be reconstituted in the immunodeficient NCG-X mice by transplanting AHCY deficient erythroblasts. Mechanistically, AHCY deficiency reduced global H3K4me3 levels and altered its genomic distribution, resulting in the upregulated expression of non-erythroid transcription factors and downregulated expression of erythrocyte lineage-specific transcription factors. Integrated single-cell analyses identified transitional states with diminished AHCY in the erythroblasts of acute myeloid leukemia (AML) patient. Further flow cytometry confirmed the reduced H3K4me3 level in patient derived erythroid cells. Erythroblasts isolated from AML patients with reduced H3K4me3 exhibited dedifferentiation potential into progenitor-like states. Our findings reveal a metabolic-epigenetic axis governing cell fate reprogramming in human erythropoiesis and provide insights into leukemia associated anemia.
Authors
Lei Sun, Hengchao Zhang, Mengjia Li, Quande Lin, Xiuyun Wu, Ying Cheng, Shihui Wang, Yan Hou, Yaomei Wang, Yue Sheng, Jing Liu, Xiuli An, Ting Wang, Lixiang Chen
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ISSN: 0021-9738 (print), 1558-8238 (online)