Research
Abstract
Myofibroblasts are the cells responsible for collagen production, leading to tissue fibrosis. Because 20.5% of the total amino acids in collagen are proline, myofibroblasts must acquire a well-developed proline-producing mechanism during their differentiation. However, the detailed mechanism for myofibroblasts to acquire and keep the developed proline biosynthesis machinery remains obscure. Here, we show branched-chain amino acid transaminase 1 (Bcat1) is up-regulated in a substantial subset of Postn-expressing proto-myofibroblast-like fibroblasts, transitional cells en route to fully differentiated myofibroblasts, as well as in myofibroblasts in the fibrotic heart and liver of mice and humans and promotes the proline production. The branched-chain amino acid (BCAA) production by BCAT1 promotes SMAD3 phosphorylation via HDAC5 phosphorylation at Ser488, thereby enhancing SMAD3-dependent transcription of proline biosynthesis-related genes, Aldh18a1, Pycr1, and Eprs, in proto-myofibroblast-like fibroblasts and myofibroblasts. In BCAT1-deficient mice, expression of proline biosynthesis-related genes is significantly attenuated in their hearts after myocardial infarction, resulting in decreased cardiac fibrosis. Moreover, BCAT1 inhibitor treatment of mice with myocardial infarction reduces cardiac fibrosis. Our results identified a BCAT1-mediated pathway that promotes collagen production via proline biosynthesis regulation in proto-myofibroblast-like fibroblasts and myofibroblasts, which may provide a therapeutic target for cardiac fibrosis.
Authors
Noburo Takizawa, Takanori Hironaka, Hayato Watanabe, Haruna Suetsugu, Keisuke Yoshioka, Yuma Horii, Yuri Nagata, Hiroaki Matoba, Hidetaka Kosako, Kenji Hamase, Go Hirai, Michio Nakaya
Abstract
Cockayne Syndrome (CS) is an autosomal recessive, progressive developmental and neurodegenerative disease. Approximately 30% of cases are caused by mutations in the ERCC8/CSA gene. Patients with CS present with cutaneous photosensitivity, growth failure, shorter life span, and a progressive degeneration of the central nervous system. Loss-of-function mutations in CSA result in deficiencies in the transcription-coupled nucleotide excision repair (TC-NER). Currently, no therapies are available for these patients. Adeno-associated virus (AAV)-mediated gene therapy offers an opportunity to address this unmet need. We designed a new AAV vector encoding human CSA under a ubiquitous promoter. We tested the therapeutic efficacy of this AAV9-CSA vector by neonatal intracerebroventicular injection in the Csa–/–;Xpa–/– mouse model. Treatment with AAV9-CSA resulted in a significant increase in lifespan, and broad distribution of human CSA in the brain and heart, without evidence of vector-related toxicity. Despite clear therapeutic benefit, we also observed neuroradiological abnormalities, and neuropathologic alterations, including hypomyelination, astrocytosis, and microgliosis, as well as likely life-limiting transcriptomic alterations in liver at endpoint. Nonetheless, the success of these experiments paves the way for the first clinical translation of an AAV gene therapy for CS patients into humans.
Authors
Ana Rita Batista, Aine C. Scholand, William S. Callahan, McKenna K. Watson, Cassandra M. Sion, Tyler Mola, Kennedy O'Hara, Simon A. Wentworth, William S. Sena-Esteves, Oliver D. King, Robert M. King, Miguel Sena-Esteves
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
Autosomal dominant polycystic kidney disease (ADPKD) accounts for 5-10% of prevalent end-stage kidney failure (ESKD). ADPKD cysts result from a loss of sufficient functional expression of PKD1/Polycystin-1 (PC1) in approximately 80% of families. Kidney disease severity correlates with the extent to which PC1 dosage is reduced below a critical level, and evidence suggests therapeutic benefit from increasing PC1 expression in these conditions. Upstream open reading frame (uORF) translation can reduce translation of a protein’s coding sequence. Ribosome profiling data and bioinformatic predictions suggested the presence of conserved PKD1 uORFs, so we sought to explore their biological role. We generated luciferase reporters and two humanized PKD1 5’UTR mouse models with or without single nucleotide edits removing uORF start codons (“delta-uORF”) to define active uORFs and test their impact on PC1 translation. PKD1 uORF start codons can robustly initiate translation and delta-uORF conveys a 2-4-fold increase in PC1 protein expression and resultant prevention of kidney cysts in Dnajb11 as well as in Pkd1 missense models. PKD1 uORF1-blocking steric antisense oligonucleotides (ASOs) substantially increase PC1 expression in vitro. PKD1 uORFs play an important role in the low basal expression of wild-type PKD1, and their inhibition represents an opportunity to therapeutically increase PC1 translation in polycystic kidney and liver disease resulting from reduced dosage of PC1.
Authors
Zhigui Li, Zi Guo, Soyoung Cho, Rishi Bhardwaj, Ke Dong, Sorin Fedeles, Whitney Besse
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
During early pregnancy, maternal blood surrounds the embryo before the placenta is fully developed, requiring tight regulation of maternal blood flow into the placental vasculature. We identify placental microthrombi (PMTs) as essential structures guiding this process. PMTs contain platelets, coagulation factors, and complement proteins, and their formation depends on maternal platelet activation by thrombin through the protease-activated receptor PAR4 (F2rl3). Deficiency of PAR4 abolished PMTs and caused excessive bleeding at the implantation site. C3 deficiency also led to increased bleeding events, indicating that complement activation contributes to thrombosis in the placental circulation. Conversely, dysregulated complement activation in CMP-sialic acid synthase-deficient (Cmas-/-) mice led to widespread thrombosis and failed placental development. Strikingly, platelet activation via PAR4 was necessary to localize complement activation to trophoblast surfaces, thereby coupling coagulation and complement in PMT formation. Depletion of maternal platelets mitigated complement-driven thromboinflammation in Cmas-/- pregnancies, restoring placental growth. These findings uncover a critical cooperation between platelets, coagulation, and complement in establishing maternal blood flow to the placenta. Successful pregnancy therefore requires not only activation but also tight regulation of these systems to balance necessary PMT formation with the prevention of pathological thrombosis.
Authors
Arno Smid, Lisa Schumann, Olga Oleshko, Ulrike Peters-Bernard, Kerstin Flächsig-Schulz, Melissa Whitehead, Emma Arndt, Korbinian Brand, Sonja Werwitzke, Andreas Klos, Bryan Paul Morgan, Wioleta M. Zelek, Andreas Tiede, Markus Abeln
Abstract
Ex vivo engineering strategies for adoptive αβ T-cell therapies increasingly use pharmacological modulation to improve survival, expansion, and antitumor activity. Short-term exposure to the BCL-2 inhibitor venetoclax during αβ T-cell manufacturing enhances apoptotic priming and effector persistence, suggesting a route to strengthen other T-cell lineages. γδ T cells share cytotoxic properties with αβ T cells but recognize targets independently of major histocompatibility complex (MHC) and show low alloreactivity, supporting off-the-shelf use in acute myeloid leukemia (AML). Whether such conditioning benefits γδ T cells was unknown. Here, we show that ex vivo venetoclax pretreatment enhances the antileukemic efficacy of therapeutic γδ T cells and chimeric antigen receptor (CAR) γδ T cells. Venetoclax-pretreated γδ T cells displayed increased cytotoxicity and proliferation with reduced exhaustion, yielding superior control of AML blasts and xenografts. These functional gains coincided with elevated mitochondrial content and a fatty acid oxidation metabolic profile. In vivo, venetoclax-pretreated γδ T cells achieved durable disease suppression, and the same conditioning improved CAR γδ T-cell efficacy. Together, these results show that short-term BCL-2 inhibition enhances γδ T-cell cytotoxicity and persistence. Incorporating venetoclax pretreatment into γδ T-cell manufacturing may improve therapeutic efficacy and inform next-generation γδ T-cell therapies for AML.
Authors
Xingchi Chen, Lin Zhang, Bingbing Yan, Yinqiang Sui, Weiwei Ma, Hui Zhao, Yining Wang, Kepeng Yang, Jiewen Ma, Baolin Tang, Yonghui Zhang, Xiaoyu Zhu
Abstract
Regulatory T (Treg) cells in visceral adipose tissue (VAT) play essential roles in systemic metabolic homeostasis under distinct physiological and pathological conditions. However, the metabolic cues that drive Treg cell subset specialization in the obese VAT niche remain elusive. Here, we demonstrated that palmitic acid instigated chronic VAT inflammation and systemic metabolic disturbance by compromising the immunosuppressive function of the ICOShi Treg subset. Palmitic acid, but not oleic acid, activated Crebzf expression in VAT Treg cells from HFHS diet-induced obese and ob/ob mice. Crebzf deficiency significantly attenuated diet-induced obesity and inflammation by upregulating the suppressive function of VAT ICOShi Treg cells. Moreover, adoptive transfer of Crebzf-deficient ICOShi Treg cells into Rag1-/- mice alleviated HFHS diet-induced inflammation and metabolic disorders more effectively than transfer of Crebzf-sufficient ICOShi Treg cells. Mechanistically, CREBZF interacted with c-JUN to inhibit Foxp3 activity, thereby impairing the stability and inhibitory cytokine production of ICOShi Treg cells. In human subjects, CREBZF levels in VAT Treg cells were elevated and negatively correlated with FOXP3 activity. Collectively, these findings uncover a specific ICOShi Treg subset that responds to palmitic acid, thereby coupling obesogenic signals to VAT remodeling and systemic metabolic homeostasis.
Authors
Weitong Su, Yuxiao Liu, Xi Yan, Mengyao Huang, Linghao Xu, Jing Lin, Xufeng Chen, Puyuan Hu, Chenlin Gao, Jian Wen, Hongdong Wang, Dong Ding, Zengpeng Zheng, Wenjing Li, Lianjia Li, Zhan Liu, Keyu Qian, Jing Gao, Tingting Zhang, Xiaobing Mao, Haibing Zhang, Wei Lu, Bin Li, Hong Li, Aoyuan Cui, Yan Bi, Chunxiang Zhang, Yu Li
Abstract
Human carcinomas often gain aggressive characteristics and escape cell-type specific treatment regimens through cryptic shifts in lineage states. However, the underlying mechanisms that govern lineage plasticity in carcinomas are undefined. Here in this study, we found that PAX5, a neural/lymphatic transcription factor, contributed to neuroendocrine (NE) lineage transition. PAX5 was highly expressed in aggressive human NE carcinoma cells and tissues but not in non-NE cancer cells and tissues. Deletion of Pax5 in Rb1fl/fl;Trp53fl/fl mice caused a reduction of tumor vessels, loss of NE morphologic features and decreased expression of ASCL1, NCAM, and SYP, whereas ectopic expression of PAX5 in CC10-rtTA;TetO-hEGFRex19del/T790M mice adenocarcinomas and in LNCAP prostate cancer xenografts induces an angiogenic microenvironment and NE morphology. Importantly, antiangiogenic drugs reduced NE features of Rb1fl/fl;Trp53fl/fl tumors and blocked PAX5-induced NE transformation. These studies demonstrate an essential role of angiogenic microenvironment in transition/maintenance of NE lineage, suggesting that targeting PAX5 and its downstream signaling may modulate lineage transitions responsible for treatment failure in both SCNCs and adenocarcinomas.
Authors
Ailing Wu, Yujie Hao, Xuemiao Yan, Junrong Liu, Lin Wang, Yan Jin, Wenxu Liu, Xiyue Chen, Yuan Jiang, Luc Girard, Zhiqun Shang, Jun Yan, Zhenfa Zhang, Wenchen Gong, Yuanjie Niu, Benjamin J. Drapkin, John D. Minna, Lance S. Terada, Zhenyi Ma, Zhe Liu
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Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)