Research
Abstract
Ulcerative colitis (UC) is a chronic inflammatory condition of the colon that primarily affects the mucosal layer. Previously, we identified autoantibodies against integrin αvβ6 in patients with UC. In this study, we established monoclonal antibodies (mAbs) from patients with UC to reveal the features and functions of these anti-integrin αvβ6 autoantibodies. We identified two shared heavy chain complementarity-determining region (CDR) 3 amino acid sequences among different patients with UC. Notably, several mAbs contained the RGD sequence in their heavy chain CDR3 that mimicked the key recognition sequence of integrin αvβ6 ligands such as fibronectin. Almost all mAbs selectively reacted with integrin αvβ6 in the presence of divalent cations (Ca²⁺ and Mg²⁺) and blocked fibronectin–integrin αvβ6 binding. MAbs that shared the same heavy chain CDR3 amino acid sequence showed differences in reactivity to integrin αvβ6, indicating that the reactivity of these mAbs is also affected by the light chain. Some of the mAbs showed varying degrees of cross-reactivity with integrin αvβ3. The identification of shared CDR3 amino acid sequences in anti-integrin αvβ6 antibodies from several patients with UC suggests a common mechanism underlying their production, which may help elucidate the pathogenesis of UC.
Authors
Masahiro Shiokawa, Yoshihiro Nishikawa, Ikuhisa Takimoto, Takeshi Kuwada, Sakiko Ota, Darryl Joy C. Juntila, Takafumi Yanaidani, Kenji Sawada, Ayako Hirata, Muneji Yasuda, Koki Chikugo, Risa Nakanishi, Masataka Yokode, Yuya Muramoto, Shimpei Matsumoto, Tomoaki Matsumori, Tsutomu Chiba, Hiroshi Seno
Abstract
Cardiomyocyte growth is tightly controlled by multiple signaling pathways. Identification of master kinases in this process is essential in exploring potential targets for the treatment of pathological cardiac hypertrophy and heart failure. Here we identified the mTOR-independent activation of ribosomal protein S6 kinase b1 (Rps6kb1/S6K1) during cardiomyocyte growth. By utilizing phosphoproteomics in primary neonatal rat ventricular myocytes (NRVMs), we revealed Rps6kb1 as one of most activated kinases under growth stimulation. We further demonstrated the role of Rps6kb1 phosphorylation in pathological cardiac hypertrophy and heart failure. We showed that the phosphorylation of multiple sites at Rps6kb1, including T367 in the kinase domain and S418/T421/S424 in the C-terminal domain, is not directly regulated by the activity of mTOR, rather coupled with the activation of the MEK1-ERK axis. In mice, cardiomyocyte-specific deletion of Rps6kb1 significantly inhibited both constitutively active ERK- and pressure overload-induced cardiac hypertrophy. In contrast, cardiomyocyte-specific overexpression of wild-type Rps6kb1, rather than the phosphorylation-defective mutant, elevated cardiac hypertrophy and augmented pressure overload-induced heart failure. In conclusion, our findings reveal that the MEK-ERK axis primes Rps6kb1 activation through phosphorylation of two separate domains of Rps6kb1, which may play an essential role in cardiac hypertrophy and heart failure under hemodynamic stress.
Authors
Chao Li, Pengfei Zhang, Kai Zhang, Jane A. Cook, Weidan Song, Megan Virostek, Lily A. Slotabec, Nadiyeh Rouhi, Mohammed Hazari, Michael I. Adenawoola, Xiaofei Liu, Hao Zhang, Guangyu Zhang, Erica L Niewold, Qinfeng Li, Yong Fang, Waleed M. Elhelaly, Xue-Nan Sun, Xuejiang Guo, Andrew Lemoff, Yingfeng Deng, Thomas G. Gillette, Ji Li, Philipp E. Scherer, Zhao V. Wang
Abstract
Radiotherapy is a critical modality in cancer treatment, not only to eradicate cancer cells but also to trigger anti-tumor immunity. Interleukin-21 (IL-21), an immunomodulatory cytokine with potential in cancer therapy, has unexplored synergy with radiotherapy. Our study, leveraging human cancer databases and tissue microarrays, identified a positive correlation between IL-21 and radiotherapy outcomes, particularly in tumor microenvironment (TME) activation. In mouse tumor models, IL-21 combined with radiation significantly enhances TME, boosting CD8+ T cell activation and function, reducing tumor burden, and extending survival. Single-cell transcriptome sequencing revealed that the combination of IL-21 and radiation increased the cytotoxicity of effector and memory CD8+ T cells and prevented their exhaustion. These effects were further validated in humanized mice, where IL-21 combined with radiation reduced A549 tumor growth and enhanced CD8+ T cell function. Post-neoadjuvant radiotherapy samples from patients with esophageal cancer showed a positive correlation between IL-21 levels and CD8+ T cell infiltration. Our findings suggest that IL-21 is a promising adjuvant to radiotherapy, potentially improving the treatment efficacy through TME enhancement. This study provides a foundation for future clinical exploration of IL-21 for enhancing radiotherapy.
Authors
Xinyang Li, Xueqi Xie, Baochao Wei, Xiaozheng Sun, Minxin Chen, Rufei Liu, Qingxu Tao, Yiheng Huang, Qian Wang, Shuangshuang Ma, Ling Wei, Rong Xiao, Zhaoyun Liu, Jinming Yu, Meng Wu, Dawei Chen
Abstract
Congenital long QT syndrome (LQTS) promotes risk for life-threatening cardiac arrhythmia and sudden death in children and young adults. Pathogenic variants in the voltage-gated potassium channel KCNQ1 are the most frequently discovered genetic cause. Most LQTS-associated KCNQ1 variants cause loss-of-function secondary to impaired trafficking of the channel to the plasma membrane. There are currently no therapeutic approaches that address this underlying molecular defect. Using a high-throughput screening paradigm, we identified VU0494372, a small molecule that increases total and cell surface levels and trafficking efficiency of WT KCNQ1 as well as three LQTS-associated variants. Additionally, 16-hour treatment of cells with VU0494372 increased IKs (KCNQ1-KCNE1 current) for WT KCNQ1 and the LQTS-associated variant V207M in cells co-expressing KCNE1. VU0494372 had no impact on KCNQ1 transcription, degradation, or thermal stability, and increased the rate of KCNQ1 reaching the cell surface. We identified a potential direct interaction site with KCNQ1 at or near the binding site of the KCNQ1 potentiator ML277. Together, these findings demonstrate that small molecules can increase the expression levels and cell surface trafficking efficiency of KCNQ1 and introduce a potential new pharmacological approach for treating LQTS.
Authors
Katherine R. Clowes Moster, Carlos G. Vanoye, Ana C. Chang-Gonzalez, Ian M. Romaine, Katherine M. Stefanski, Mason C. Wilkinson, Joshua A. Bauer, Thomas P. Hasaka, Emily L. Days, Reshma R. Desai, Kathryn R. Butcher, Gary A. Sulikowski, Alex G. Waterson, Jens Meiler, Kaitlyn V. Ledwitch, Alfred L. George, Jr., Charles R. Sanders
Abstract
Sustained injury to renal tubular epithelial cells (TECs), driven by excessive autophagy, is a critical mechanism underlying kidney fibrosis. Our previous work identified JLP—a TEC-expressed scaffolding protein—as an endogenous anti-fibrotic factor that counteracts TGF-β1–induced autophagy and fibrogenesis. However, the mechanism underlying JLP downregulation in renal fibrosis remains unclear. Here, we delineated a TGF-β1/LEF1/β-catenin/JLP axis that governed TEC autophagy through a dichotomous regulatory circuit. Under physiological conditions, low levels of β-catenin and LEF1 with minimal nuclear localization permit normal JLP expression, which in turn maintains autophagy in check. In contrast, during renal injury, TGF-β1 promoted the expression and nuclear translocation of β-catenin and LEF1, which together suppressed JLP transcription. This loss of JLP-mediated inhibition led to unchecked autophagy and exacerbated fibrotic damage. Analyses of kidney tissues from patients with CKD, murine fibrotic kidneys, and cultured HK-2 cells confirmed consistent JLP downregulation accompanied by upregulation and nuclear accumulation of LEF1 and β-catenin. Therapeutic intervention using the β-catenin/LEF1 inhibitor iCRT3 or LEF1-targeted silencing in murine fibrosis models restored JLP expression, attenuated TEC autophagy, and ameliorated renal fibrosis. These findings revealed an autoregulatory circuit controlling TEC autophagy and fibrogenesis, and supported LEF1 and β-catenin as potential therapeutic targets in CKD.
Authors
Chen Li, Meng Zhang, Maoqing Tian, Zeyu Tang, Yuying Hu, Yuyu Long, Xiaofei Wang, Liwen Qiao, Jiefei Zeng, Yujuan Wang, Xinghua Chen, Cheng Chen, Xiaoyan Li, Lu Zhang, Huiming Wang
Abstract
Next generation sequencing can identify previously uncharacterized gene expression patterns in disease. Beyond differentially expressed genes analysis, we investigated the ability of within-population diversity (α-diversity) of the transcriptome to reveal additional biological information in alcohol-associated liver disease (ALD), comparing Differential Shannon diversity (DSD) to transcriptome heterogeneity changes. RNA sequencing data from normal livers and patients with early ALD and severe AH were analyzed. α-diversity indices and Percent Shannon Diversity of a gene, which refers to this gene's contribution to total Shannon entropy, were calculated. Ingenuity pathway analysis identified canonical pathways determined by differentially expressed genes (DEG) and DSD approaches. ALD significantly decreased hepatic transcriptome α-diversity correlating with increased relative contribution of select genes. These changes were driven by lower abundance gene expression loss. DEG and DSD analyses showed overlapping genes and canonical pathways, but DSD also identified additional genes and pathways not highlighted by DEG, including fatty acid oxidation, extracellular matrix degradation, and cholesterol metabolism pathways that may represent additional therapeutic targets. Importantly, DSD more effectively identified differences between ASH and AH. Overall, α-diversity analysis revealed that ALD progressively reduces transcriptome heterogeneity, and that DSD provides complementary insights into disease mechanisms missed by standard approaches.
Authors
Sudrishti Chaudhary, Jia-Jun Liu, Silvia Liu, Marissa Di, Juliane I. Beier, Ramon Bataller, Josepmaria Argemi, Panayiotis V. Benos, Gavin E. Arteel
Abstract
Activation of lung fibroblasts in response to epithelial injury and inflammation provokes pulmonary fibrosis (PF). Endogenous molecular brakes counteracting fibroblast activity can be targets for therapies. Preclinical studies of synthetic C-type natriuretic peptide (CNP) indicated that this hormone might provide such a brake. As shown here, CNP exerts antifibrotic effects in cultured lung fibroblasts as well as precision cut lung slices from patients with PF, supporting clinical relevance. Therefore, augmenting or supplementing endogenous CNP could improve the treatment of such patients. To unravel whether paracrine CNP counteracts inflammation-driven PF, we studied mice with fibroblast-restricted knock-out of guanylyl-cyclase-B (GC-B), its cGMP-synthesizing receptor. Fibroblast GC-B-KO mice had enhanced bleomycin-induced lung inflammation, with increased expression of proinflammatory, profibrotic cytokines. Nevertheless, subsequent PF was not exacerbated. Molecular studies revealed that inflammation led to inhibition of CNP signaling in resident myofibroblasts, namely GC-B downregulation and induction of CNP/cGMP-degrading pathways. Despite this, a single subcutaneous injection of the recently developed long-acting CNP analog, MS~[Gln6,14]CNP-38, abrogated experimental lung inflammation and fibrosis. We conclude that CNP signaling in lung fibroblasts has anti-inflammatory and antifibrotic effects. Attenuation of this endogenous brake participates in the pathogenesis of PF and rescuing this pathway with long-acting CNP-analogs may have therapeutic potential.
Authors
Rene Weyer, Katharina Völker, Tamara Potapenko, Lisa Krebes, Marco Abesser, Anna-Lena Friedrich, Eva Lessmann, Ali Khadim, Clemens Ruppert, Elie El Agha, Dalia Sheta, Andreas Beilhack, Daniel V. Santi, Eric L. Schneider, Michaela Kuhn, Swati Dabral
Abstract
Iron regulatory protein 1 (IRP1) is a post-transcriptional regulator of cellular iron metabolism. In mice, loss of IRP1 causes polycythemia through translational de-repression of hypoxia-inducible factor 2α (HIF2α) mRNA, which increases renal erythropoietin production. Here we show that Irp1-/- mice develop fasting hypoglycemia and are protected against high-fat diet–induced hyperglycemia and hepatic steatosis. Discovery-based proteomics of Irp1-/- livers revealed a mitochondrial dysfunction signature. Seahorse flux analysis in primary hepatocytes and differentiated skeletal muscle myotubes confirmed impaired respiratory capacity, with a shift from oxidative phosphorylation to glycolytic ATP production. This metabolic rewiring was associated with enhanced insulin sensitivity and increased glucose uptake in skeletal muscle. Under metabolic stress, IRP1 deficiency altered the redox balance of mitochondrial iron, resulting in inefficient energy production and accumulation of amino acids and metabolites in skeletal muscle, rendering them unavailable for hepatic gluconeogenesis. These findings identify IRP1 as a critical regulator of systemic energy homeostasis.
Authors
Wen Gu, Nicole Wilkinson, Carine Fillebeen, Darren Blackburn, Korin Sahinyan, Eric Bonneil, Tao Zhao, Zhi Luo, Vahab Soleimani, Vincent Richard, Christoph H. Borchers, Albert Koulman, Benjamin Jenkins, Bernhard Michalke, Hans Zischka, Judith Sailer, Vivek Venkataramani, Othon Iliopoulos, Gary Sweeney, Kostas Pantopoulos
Abstract
Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS) is a rare disorder caused by ACTA2 mutations, including the R179H variant, which alters actin filament stability and dynamics and smooth muscle contractility. While cardiovascular complications dominate its clinical presentation, gastrointestinal (GI) dysfunction significantly impacts quality of life. To investigate the structural, functional, and cellular basis of gut dysmotility in MSMDS, we reviewed clinical data from 24 MSMDS patients and studied the ACTA2 R179H mouse model Patients exhibited severe gut dysmotility, with 75% requiring medication for chronic constipation. ACTA2 mutant mice displayed cecal and colonic dilatation, reduced intestinal length, and disrupted colonic migrating motor complexes (CMMCs). Delayed whole-gut transit and impaired contractile responses to electrical and pharmacological stimulation were observed. Transcriptomic analysis revealed significant actin cytoskeleton-related gene changes in smooth muscle cells, and immune profiling identified increased lymphocytic infiltration. Despite functional abnormalities, there were no obvious changes in the enteric nervous system. These findings establish ACTA2 mice as a robust model for studying GI pathology in MSMDS, elucidating the role of smooth muscle dysfunction in gut dysmotility. This model provides a foundation for developing targeted therapies aimed at restoring intestinal motility by directly addressing actin cytoskeletal disruptions in smooth muscle cells.
Authors
Ahmed A. Rahman, Rhian Stavely, Leah C. Ott, Christopher Y. Han, Kensuke Ohishi, Ryo Hotta, Alan J. Burns, Sabyasachi Das, Emily Da Cruz, Diana Tambala, Mark E. Lindsay, Patricia L. Musolino, Allan M. Goldstein
Abstract
Functional antibody responses to malaria transmission-blocking vaccines (TBVs) are assessed using the Standard Membrane Feeding Assay (SMFA). This assay quantifies percentage reduction of oocyst levels in mosquitoes fed gametocytes mixed with antisera/antibodies, referred to as transmission-reducing activity (TRA). As TBVs advance to large clinical trials, new scalable assays are needed to characterize vaccine responses. Here, we developed an epitope-specific competitive ELISA platform (P230Compete) for TBV candidate Pfs230D1, based on single-chain variable fragments (scFv) against epitopes recognized by human monoclonal antibodies with high TRA. We quantified functional epitope-specific antibody responses (F) in Phase 1 Pfs230D1-EPA/AS01 vaccine trial participants, using 171 serum samples collected at two post-vaccination timepoints. Five antibody features were examined by P230Compete including total IgG (reported as ELISA units, EUF), IgG subclasses (IgG1F, IgG3F, IgG4F), and bound complement factor C1q (C1qF). EUF and IgG1F demonstrated strong correlation and excellent prediction of TRA≥80% in logistic regression analysis (AUC of 0.81 for both assays post-dose 3, and 0.80 and 0.76 post-dose 4). Furthermore, combining EUF and IgG1F showed even better predictive performance at each timepoint. P230Compete offers a promising proxy assay to replace SMFA in late-stage Pfs230D1 trials.
Authors
Cristina A. Meehan, Matthew V. Cowles, Robert D. Morrison, Yuyan Yi, Jingwen Gu, Jen C.C. Hume, Mina P. Peyton, Issaka Sagara, Sara A. Healy, Jonathan P. Renn, Patrick E. Duffy
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