Issue published April 15, 2025 Previous issue
- Volume 135, Issue 8
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On the cover: Biparatopic antibodies targeting FGFR2 fusion–driven cholangiocarcinoma
Chaturantabut et al. identify biparatopic FGFR2 antibodies that are effective against FGFR2 fusion–driven cholangiocarcinoma. The cover art depicts biparatopic antibodies binding to and crosslinking FGFR2, creating large complexes that promote FGFR2 internalization and degradation, which ultimately suppress tumor growth. Image credit: Behnoush Hajian and Mrinal Shekhar.
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Review
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Abstract
HNSCC remains a substantial health issue, with treatment options including surgery, radiation, and platinum-based chemotherapy. Unfortunately, despite progress in research, only modest gains have been made in disease control, with existing treatments resulting in significant functional and quality-of-life issues. The introduction of immunotherapy in the treatment of HNSCC has resulted in some improvements in outlook for patients and is now standard of care for populations with both recurrent and metastatic disease. However, despite the early successes, responses to immune checkpoint inhibition (ICI) remain modest to low, approaching 14%–22% objective response rates. Challenges to the effectiveness of ICI and other immunotherapies are complex, including the diverse and dynamic molecular plasticity and heterogeneity of HNSCCs; lack of immunogenic antigens; accumulated suppressive immune populations such as myeloid cells and dysfunctional T cells; nutrient depletion; and metabolic dysregulation in the HNSCC tumor microenvironment. In this Review, we explore the mechanisms responsible for immunotherapy resistance, dissect these challenges, and discuss potential opportunities for overcoming hurdles to the development of successful immunotherapy for HNSCC.
Authors
Xia Liu, R. Alex Harbison, Mark A. Varvares, Sidharth V. Puram, Guangyong Peng
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Commentaries
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Abstract
Prostate stem cell antigen (PSCA) is highly and preferentially expressed on the surface of pancreatic ductal adenocarcinoma (PDAC) cells, raising the promise of tumor-selective cell-based immunotherapies. In this issue of the JCI, Dai et al. harness PSCA for the development of an off-the-shelf chimeric antigen receptor (CAR) invariant natural killer T (iNKT) cell–based treatment for PDAC. Through in vitro experiments and in vivo models, the authors demonstrate selectivity and therapeutic efficacy of PSCA CAR_sIL15 iNKT cells against both gemcitabine-sensitive and -resistant PDAC cells with comparable antitumor activity for freshly produced and frozen off-the-shelf PSCA CAR_sIL15 iNKT cells. This development opens another potential therapeutic option for pancreatic cancer.
Authors
Rachel Elizabeth Ann Fincham, Joe Poh Sheng Yeong, Hemant Mahendrakumar Kocher
×Abstract
Vaccine hesitancy is often fueled by fears of side effects; however, most reactions result from innate immune activation and cytokine production, which are required for lasting immunity. For effective vaccines against HIV, innate activation is essential for differentiation of CD4+ T cells into T follicular helper cells (TFH), which guide rare B cells to mature into long-lived plasma cells that produce durable neutralizing antibodies (nAbs). In this issue of the JCI, Parham Ramezani-Rad et al. show that higher doses of saponin QS-21–MPLA nanoparticle (SMNP) adjuvant, combined with BG505 MD39 envelope (Env) protein, enhanced cytokine responses, drove stronger Env-specific TFH responses in blood, and increased Env-specific bone marrow plasma cells compared with lower doses. While tier 2 nAbs were sustained at memory in only a subset of animals, predominantly at the highest adjuvant dose, these findings highlight transient reactogenicity as an essential mechanism — not a flaw — for building durable immune memory.
Authors
Pabitra B. Pal, Smita S. Iyer
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A wide variety of medications can induce adverse immune events and autoimmune responses such as vasculitis. Mechanistically, small molecule drugs known as haptens bind and modify endogenous proteins, triggering such immune reactions. In this issue of the JCI, Xi and colleagues investigated the immunological mechanism of autoimmune vasculitis associated with hydralazine. Notably, hydralazine-based haptenization modified myeloperoxidase (MPO), inducing the enzyme conformational change. The hydralazine-modified MPO induced IgM antibody specific for the modified enzyme, followed by immune complex precipitation, tissue deposition, and complement activation. These findings provide a mechanism by which hydralazine induces a type III hypersensitivity reaction associated with mild to severe vasculitis. The study serves as an example for understanding haptenation and may inform the development of diagnostics for determining susceptibility to drug-induced allergic or autoimmune responses.
Authors
Laura Santambrogio
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Castration-resistant prostate cancer frequently metastasizes to the liver, and prostate cancer liver metastases often present a neuroendocrine phenotype (i.e., neuroendocrine prostate cancer [NEPC]), but the underlying molecular underpinnings remain unclear. In this issue of the JCI, Liu et al. demonstrate that the neurotransmitter serotonin (also known as 5-hydroxytryptamine), produced by NEPC cells, gained access to and activated neutrophils by modifying histone 3 (H3) to form neutrophil extracellular traps, which in turn promoted NEPC macrometastases in the liver. The study suggests that blocking serotonin transport to neutrophils and inhibiting the enzymes that catalyze serotonin-mediated H3 modifications may represent alternative approaches to treating prostate cancer liver metastases.
Authors
Dean G. Tang
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Research Letters
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Abstract
Authors
Yue Zhang, Julia A. Yescas, Kristy Tefft, Spencer Ng, Kevin Qiu, Erica B. Wang, Shifa Akhtar, Addie Walker, Macartney Welborn, Martin Zaiac, Joan Guitart, Aamir M. Qureshi, Youn H. Kim, Michael S. Khodadoust, Naiem T. Issa, Jaehyuk Choi
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Authors
Samantha Chan, Mai B. Margetts, Longfei Wang, Jack Godsell, Josh Chatelier, Belinda Liu, Charlotte A. Slade, Andrew Brett, Kasha P. Singh, Vanessa L. Bryant, Lauren J. Howson
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Research Articles
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Abstract
Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and the activated B cell–like subtype (ABC-DLBCL) is associated with particularly poor outcome. Many ABC-DLBCLs harbor gain-of-function mutations that cause inappropriate assembly of the CARMA1-BCL10-MALT1 (CBM) signalosome, a cytoplasmic complex that drives downstream NF-κB signaling. MALT1 is the effector protein of the CBM signalosome such that its recruitment to the signalosome via interaction with BCL10 allows it to exert both protease and scaffolding activities that together synergize in driving NF-κB. Here, we demonstrate that a molecular groove located between two adjacent immunoglobulin-like domains within MALT1 represents a binding pocket for BCL10. Leveraging this discovery, we performed an in silico screen to identify small molecules that dock within this MALT1 groove and act as BCL10-MALT1 protein-protein interaction (PPI) inhibitors. We report the identification of M1i-124 as a first-in-class compound that blocks BCL10-MALT1 interaction, abrogates MALT1 scaffolding and protease activities, promotes degradation of BCL10 and MALT1 proteins, and specifically targets ABC-DLBCLs characterized by dysregulated MALT1. Our findings demonstrate that small-molecule inhibitors of BCL10-MALT1 interaction can function as potent agents to block MALT1 signaling in selected lymphomas, and provide a road map for clinical development of a new class of precision-medicine therapeutics.
Authors
Heejae Kang, Lisa M. Maurer, Jing Cheng, Mei Smyers, Linda R. Klei, Dong Hu, Juliana Hofstatter Azambuja, Marcelo J. Murai, Ahmed Mady, Ejaz Ahmad, Matthew Trotta, Hanna B. Klei, Minda Liu, Prasanna Ekambaram, Zaneta Nikolovska-Coleska, Bill B. Chen, Linda M. McAllister-Lucas, Peter C. Lucas
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Elevated angiopoietin-2 is associated with diverse inflammatory conditions, including sepsis, a leading global cause of mortality. During inflammation, angiopoietin-2 antagonizes the endothelium-enriched receptor Tie2 to destabilize the vasculature. In other contexts, angiopoietin-2 stimulates Tie2. The basis for context-dependent antagonism remains incompletely understood. Here, we show that inflammation-induced proteolytic cleavage of angiopoietin-2 converts this ligand from Tie2 agonist to antagonist. Conditioned media from stimulated macrophages induced endothelial angiopoietin-2 secretion. Unexpectedly, this was associated with reduction of the 75 kDa full-length protein and appearance of new 25 and 50 kDa C-terminal fragments. Peptide sequencing proposed cathepsin K as a candidate protease. Cathepsin K was necessary and sufficient to cleave angiopoietin-2. Recombinant 25 and 50 kDa angiopoietin-2 fragments (cANGPT225 and cANGPT250) bound and antagonized Tie2. Cathepsin K inhibition with the phase 3 small-molecule inhibitor odanacatib improved survival in distinct murine sepsis models. Full-length angiopoietin-2 enhanced survival in endotoxemic mice administered odanacatib and, conversely, increased mortality in the drug’s absence. Odanacatib’s benefit was reversed by heterologous cANGPT225. Septic humans accumulated circulating angiopoietin-2 fragments, which were associated with adverse outcomes. These results identify cathepsin K as a candidate marker of sepsis and a proteolytic mechanism for the conversion of angiopoietin-2 from Tie2 agonist to antagonist, with therapeutic implications for inflammatory conditions associated with angiopoietin-2 induction.
Authors
Takashi Suzuki, Erik Loyde, Sara Chen, Valerie Etzrodt, Temitayo O. Idowu, Amanda J. Clark, Marie Christelle Saade, Brenda Mendoza Flores, Shulin Lu, Gabriel Birrane, Vamsidhara Vemireddy, Benjamin Seeliger, Sascha David, Samir M. Parikh
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Chronic liver injury triggers the activation and recruitment of immune cells, causing antigen-independent tissue damage and liver disease progression. Tissue inflammation can reshape macrophage composition through monocyte replacement. Replacement of tissue macrophages with monocytes differentiating in an inflammatory environment can potentially imprint a phenotype that switches the liver from an immune-tolerant organ to one predisposed to tissue damage. We longitudinally sampled the liver of patients with chronic hepatitis B who had active liver inflammation and were starting antiviral therapy. Antiviral therapy suppressed viral replication and liver inflammation, which coincided with decreased myeloid activation markers. Single-cell RNA-Seq mapped peripheral inflammatory markers to a monocyte-derived macrophage population, distinct from Kupffer cells, with an inflammatory transcriptional profile. The inflammatory macrophages (iMacs) differentiated from blood monocytes and were unique from macrophage found in healthy or cirrhotic liver. iMacs retained their core transcriptional signature after inflammation resolved, indicating inflammation-mediated remodeling of the macrophage population in the human liver that may affect progressive liver disease and immunotherapy.
Authors
Juan Diego Sanchez Vasquez, Shirin Nkongolo, Daniel Traum, Valentin Sotov, Samuel C. Kim, Deeqa Mahamed, Aman Mehrotra, Anjali Patel, Diana Y. Chen, Scott Fung, Anuj Gaggar, Jordan J. Feld, Kyong-Mi Chang, Jeffrey J. Wallin, Ben X. Wang, Harry L.A. Janssen, Adam J. Gehring
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RAS/MAPK pathway mutations often induce RASopathies with overlapping features, such as craniofacial dysmorphology, cardiovascular defects, dermatologic abnormalities, and intellectual disabilities. Although B-Raf proto-oncogene (BRAF) mutations are associated with cardio-facio-cutaneous (CFC) syndrome and Noonan syndrome, it remains unclear how these mutations impair cognition. Here, we investigated the underlying neural mechanisms using several mouse models harboring a gain-of-function BRAF mutation (K499E) discovered in RASopathy patients. We found expressing BRAF K499E (KE) in neural stem cells under the control of a Nestin-Cre promoter (Nestin;BRAFKE/+) induced hippocampal memory deficits, but expressing it in excitatory or inhibitory neurons did not. BRAF KE expression in neural stem cells led to aberrant reactive astrogliosis, increased astrocytic Ca2+ fluctuations, and reduced hippocampal long-term depression (LTD) in mice. Consistently, 3D human cortical spheroids expressing BRAF KE also showed reactive astrogliosis. Astrocyte-specific adeno-associated virus–BRAF KE (AAV-BRAF KE) delivery induced memory deficits and reactive astrogliosis and increased astrocytic Ca2+ fluctuations. Notably, reducing extracellular signal-regulated kinase (ERK) activity in astrocytes rescued the memory deficits and altered astrocytic Ca2+ activity of Nestin;BRAFKE/+ mice. Furthermore, reducing astrocyte Ca2+ activity rescued the spatial memory impairments of BRAF KE–expressing mice. Our results demonstrate that ERK hyperactivity contributes to astrocyte dysfunction associated with Ca2+ dysregulation, leading to the memory deficits of BRAF-associated RASopathies.
Authors
Minkyung Kang, Jihye Choi, Jeongho Han, Toshiyuki Araki, Soo-Whee Kim, Hyun-Hee Ryu, Min-Gyun Kim, Seoyeon Kim, Hanbyul Jang, Sun Yong Kim, Kyoung-Doo Hwang, Soobin Kim, Myeongjong Yoo, Jaegeon Lee, Kitae Kim, Pojeong Park, Ja Eun Choi, Dae Hee Han, Yujin Kim, Jeongyeon Kim, Sunghoe Chang, Bong-Kiun Kaang, Jung Min Ko, Keun-Ah Cheon, Joon-Yong An, Sang Jeong Kim, Hyungju Park, Benjamin G. Neel, Chul Hoon Kim, Yong-Seok Lee
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BACKGROUND Pneumocystis jirovecii pneumonia (PCP) is a leading cause of fungal pneumonia, but its diagnosis primarily relies on invasive bronchoalveolar lavage (BAL) specimens that are difficult to obtain. Oropharyngeal swabs and serum could improve the PCP diagnostic workflow, and we hypothesized that CRISPR could enhance assay sensitivity to allow robust P. jirovecii diagnosis using swabs and serum. Herein, we describe the development of an ultrasensitive RT-PCR–coupled CRISPR assay with high active-infection specificity in infant swabs and adult BAL and serum.METHODS Mouse analyses employed an RT-PCR CRISPR assay to analyze P. murina transcripts in WT and Rag2–/– mouse lung RNA, BAL, and serum at 2-, 4-, and 6-weeks after infection. Human studies used an optimized RT-PCR CRISPR assay to detect P. jirovecii transcripts in infant oropharyngeal swab samples, adult serum, and adult BAL specimens from patients who were infected with P. jirovecii and those who were not.RESULTS The P. murina assays sensitively detected Pneumocystis RNA in the serum of infected mice throughout infection. Oropharyngeal swab CRISPR assay results identified infants infected with P. jirovecii with greater sensitivity (96.3% versus 66.7%) and specificity (100% versus 90.6%) than RT-qPCR compared with mitochondrial large subunit rRNA gene (mtLSU) standard marker, and CRISPR results achieved higher sensitivity than RT-qPCR results (93.3% versus 26.7%) in adult serum specimens.CONCLUSION Since swabs are routinely collected in pediatric patients with pneumonia and serum is easier to obtain than BAL, this assay approach could improve the accuracy and timing of pediatric and adult Pneumocystis diagnosis by achieving specificity for active infection and potentially avoiding the requirement for BAL specimens.FUNDING The work was supported by the NIH (R01AI120033), NHLBI (R35HL139930), the Louisiana Board of Regents Endowed Chairs for Eminent Scholars program, and by research funding provided by National Institute of Allergy and Infectious Diseases (NIAID) (R01AI144168, R01AI175618, R01AI173021). This research was also funded by the NIHR (project 134342) using UK aid from the UK government to support global health research.
Authors
Brady M. Youngquist, Ayanda Trevor Mnguni, Dora Pungan, Rachel PJ Lai, Guixiang Dai, Chun Fai Ng, Amy Samson, Yasmean Abdelgaliel, Christopher J. Lyon, Bo Ning, Shahid Husain, Sean Wasserman, Jay K. Kolls, Tony Y. Hu
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Super-enhancers (SEs) are expansive cis-regulatory elements known for amplifying oncogene expression across various cancers. However, their role in cervical cancer (CC), a remarkable global malignancy affecting women, remains underexplored. Here we applied integrated epigenomic and transcriptomic profiling to delineate the distinct SE landscape in CC by analyzing paired tumor and normal tissues. Our study identifies a tumor-specific SE at the EFNA1 locus that drives EFNA1 expression in CC. Mechanically, the EFNA1-SE region contains consensus sequences for the transcription factor FOSL2, whose knockdown markedly suppressed luciferase activity and diminished H3K27ac enrichment within the SE region. Functional analyses further underlined EFNA1’s oncogenic role in CC, linking its overexpression to poor patient outcomes. EFNA1 knockdown strikingly reduced CC cell proliferation, migration, and tumor growth. Moreover, EFNA1 cis-interacted with its receptor EphA2, leading to decreased EphA2 tyrosine phosphorylation and subsequent activation of the Src/AKT/STAT3 forward signaling pathway. Inhibition of this pathway with specific inhibitors substantially attenuated the tumorigenic capacity of EFNA1-overexpressing CC cells in both in vitro and in vivo models. Collectively, our study unveils the critical role of SEs in promoting tumor progression through the FOSL2-EFNA1-EphA2-Src/AKT/STAT3 axis, providing new prognostic and therapeutic avenues for CC patients.
Authors
Shu-Qiang Liu, Xi-Xi Cheng, Shuai He, Tao Xia, Yi-Qi Li, Wan Peng, Ya-Qing Zhou, Zi-Hao Xu, Mi-Si He, Yang Liu, Pan-Pan Wei, Song-Hua Yuan, Chang Liu, Shu-Lan Sun, Dong-Ling Zou, Min Zheng, Chun-Yan Lan, Chun-Ling Luo, Jin-Xin Bei
×Abstract
Drug-induced autoimmune diseases are increasingly recognized, although mechanistic insight into disease causation is lacking. Hydralazine exposure has been linked to autoimmune diseases, including antineutrophil cytoplasmic autoantibody (ANCA) vasculitis. Our hypothesis posits that hydralazine covalently binds to myeloperoxidase (MPO), triggering the autoimmune response in ANCA vasculitis. In vitro, we observed formation of carbonyl derivatives on amine groups in the presence of acrolein. This facilitated the subsequent binding of hydralazine to heme-containing proteins, including MPO, via a Michael addition. Our studies demonstrated that carbonyl derivatives and hydrazone adducts induced conformational changes in the MPO heavy chain, potentially changing its immunogenicity. We identified hydrazone adducts on circulating MPO in patients with hydralazine-associated ANCA vasculitis. These patients exhibited elevated anti-MPO IgM levels, while anti-MPO IgG levels were comparable between hydralazine-associated and nonhydralazine-associated vasculitis patients. IgM isolated from patients with hydralazine-associated MPO ANCA demonstrated a heightened affinity to hydralazine-modified MPO and activated neutrophil-like HL-60 cells. Hydralazine-modified MPO was pathogenic, as demonstrated by splenocyte transfer in a mouse model of ANCA vasculitis. Our findings unveil a mechanism of drug-induced autoimmunity wherein stepwise chemical modifications of MPO lead to conformational changes and hydrazone adduct formation, producing a neoantigen that generates pathogenic autoantibodies.
Authors
Gang Xi, Elizabeth A. Mclnnis, Olivier Lardinois, Peiqi Hu, John S. Poulton, Meghan E. Free, Dhruti P. Chen, Evan M. Zeitler, Eveline Y. Wu, Nicole M. Orzechowski, Vimal K. Derebail, J. Charles Jennette, Ronald J. Falk
×Abstract
Pancreatic ductal adenocarcinoma cancer (PDAC) continues to pose a significant health burden, with a 5-year survival rate of only 10%. Prostate stem cell antigen (PSCA) is highly expressed on the surface of tumor cells of most PDAC patients, with minimum expression in most normal tissues. Here, we generated cryopreserved, off-the-shelf, allogeneic PSCA chimeric antigen receptor (CAR) invariant NKT (iNKT) cells using human peripheral blood mononuclear cells as a cell source. In multiple in vitro and in vivo PDAC models, freshly manufactured PSCA CAR_sIL-15 iNKT cells and frozen-thawed, off-the-shelf PSCA CAR_sIL-15 iNKT cells demonstrate comparable efficacies, and both show remarkable suppression of PSCA-positive and gemcitabine-resistant PDAC. Importantly, off-the-shelf cryopreserved PSCA CAR_sIL-15 iNKT cells show equivalent efficacy when compared with PSCA CAR T cells using the same PSCA CAR and in the same PDAC model; however, PSCA CAR_sIL-15 iNKT cells do not appear to induce systemic toxicity or graft-versus-host disease, thus allowing for multiple infusions to control recurrent disease. Collectively, our study suggests that PSCA CAR_sIL-15 iNKT cells merit clinical investigation for PDAC patients exhibiting positive PSCA expression. The therapy could be given as a single agent or in combination with established therapeutic modalities for PDAC.
Authors
Zhenyu Dai, Zheng Zhu, Zhiyao Li, Lei Tian, Kun-Yu Teng, Hanyu Chen, Li-Shu Wang, Jianying Zhang, Laleh Melstrom, Michael A. Caligiuri, Jianhua Yu
×Abstract
Genome-wide human genetic studies have identified inherited cis-regulatory loci variants that predispose to cancers. However, the mechanisms by which these germline variants influence cancer progression, particularly through gene expression and proteostasis control, remain unclear. By analyzing genomic data from a gastric cancer (GC) case-control study (2,117 individuals), focusing on the ubiquitin-specific protease (USP) family, we identify the SNP rs72856331 (G>A) in the promoter region of the proto-oncogene USP47 as a putative susceptibility allele for GC. Mechanistically, the risk allele G is associated with enhanced USP47 expression, mediated by altered recruitment of the transcription factor GLI3 and changes in the epigenetic status at promoter. CRISPR/Cas9-mediated single-nucleotide conversion into risk allele G results in increased GLI3 binding and subsequent USP47 upregulation. The depletion of GLI3 results in a reduction of cancer-related phenotypes, similar to those observed following USP47 knockdown. Furthermore, we identify Snai1 as a deubiquitination target of USP47, explaining USP47-dependent activation of the epithelial-mesenchymal transition pathway and tumor progression. Our findings identify an important genetic predisposition that implicates the perturbation of transcription and proteostasis programs in GC, offering insights into prevention and therapeutic strategies for genetically stratified patients.
Authors
Bolin Tao, Zhenning Wang, Xuanyi Wang, Aixia Song, Jiaxian Liu, Jianan Wang, Qin Zhang, Zhaolin Chen, Zixian Wang, Wenjie Xu, Menghong Sun, Yanong Wang, Ping Zhang, Tao Xu, Gong-Hong Wei, Fei Xavier Chen, Mengyun Wang
×Abstract
Telomere biology disorders (TBDs) are genetic diseases caused by defective telomere maintenance. TBD patients often develop bone marrow failure and have an increased risk of myeloid neoplasms. To better understand the factors underlying hematopoietic outcomes in TBD, we comprehensively evaluated acquired genetic alterations in hematopoietic cells from 166 pediatric and adult TBD patients. Of these patients, 47.6% (28.8% of children, 56.1% of adults) had clonal hematopoiesis. Recurrent somatic alterations involved telomere maintenance genes (7.6%), spliceosome genes (10.4%, mainly U2AF1 p.S34), and chromosomal alterations (20.2%), including 1q gain (5.9%). Somatic variants affecting the DNA damage response (DDR) were identified in 21.5% of patients, including 20 presumed loss-of-function variants in ataxia-telangiectasia mutated (ATM). Using multimodal approaches, including single-cell sequencing, assays of ATM activation, telomere dysfunction-induced foci analysis, and cell-growth assays, we demonstrate telomere dysfunction–induced activation of the ATM-dependent DDR pathway with increased senescence and apoptosis in TBD patient cells. Pharmacologic ATM inhibition, modeling the effects of somatic ATM variants, selectively improved TBD cell fitness by allowing cells to bypass DDR-mediated senescence without detectably inducing chromosomal instability. Our results indicate that ATM-dependent DDR induced by telomere dysfunction is a key contributor to TBD pathogenesis and suggest dampening hyperactive ATM-dependent DDR as a potential therapeutic intervention.
Authors
Christopher M. Sande, Stone Chen, Dana V. Mitchell, Ping Lin, Diana M. Abraham, Jessie Minxuan Cheng, Talia Gebhard, Rujul J. Deolikar, Colby Freeman, Mary Zhou, Sushant Kumar, Michael Bowman, Robert L. Bowman, Shannon Zheng, Bolormaa Munkhbileg, Qijun Chen, Natasha L. Stanley, Kathy Guo, Ajibike Lapite, Ryan Hausler, Deanne M. Taylor, James Corines, Jennifer J.D. Morrissette, David B. Lieberman, Guang Yang, Olga Shestova, Saar Gill, Jiayin Zheng, Kelcy Smith-Simmer, Lauren G. Banaszak, Kyle N. Shoger, Erica F. Reinig, Madilynn Peterson, Peter Nicholas, Amanda J. Walne, Inderjeet Dokal, Justin P. Rosenheck, Karolyn A. Oetjen, Daniel C. Link, Andrew E. Gelman, Christopher R. Reilly, Ritika Dutta, R. Coleman Lindsley, Karyn J. Brundige, Suneet Agarwal, Alison A. Bertuch, Jane E. Churpek, Laneshia K. Tague, F. Brad Johnson, Timothy S. Olson, Daria V. Babushok
×Abstract
Translocations involving FGFR2 gene fusions are common in cholangiocarcinoma and predict response to FGFR kinase inhibitors. However, response rates and durability are limited due to the emergence of resistance, typically involving FGFR2 kinase domain mutations, and to suboptimal dosing, relating to drug adverse effects. Here, we develop biparatopic antibodies targeting the FGFR2 extracellular domain (ECD) as candidate therapeutics. Biparatopic antibodies can overcome drawbacks of bivalent monospecific antibodies, which often show poor inhibitory or even agonist activity against oncogenic receptors. We show that oncogenic transformation by FGFR2 fusions requires an intact ECD. Moreover, by systematically generating biparatopic antibodies targeting distinct epitope pairs in FGFR2 ECD, we identified antibodies that effectively block signaling and malignant growth driven by FGFR2 fusions. Importantly, these antibodies demonstrate efficacy in vivo, synergy with FGFR inhibitors, and activity against FGFR2 fusions harboring kinase domain mutations. Thus, we believe that biparatopic antibodies may serve as an innovative treatment option for patients with FGFR2-altered cholangiocarcinoma.
Authors
Saireudee Chaturantabut, Sydney Oliver, Dennie T. Frederick, Jiwan J. Kim, Foxy P. Robinson, Alessandro Sinopoli, Tian-Yu Song, Yao He, Yuan-Chen Chang, Diego J. Rodriguez, Liang Chang, Devishi Kesar, Meilani Ching, Ruvimbo Dzvurumi, Adel Atari, Yuen-Yi Tseng, Nabeel Bardeesy, William R. Sellers
×Abstract
Plasmacytoid dendritic cells (pDCs), professional type I IFN–producing cells, have been implicated in host responses against bacterial infections. However, their role in host defense is debated, and the operating molecular mechanisms are unknown. Certain signaling lymphocyte activation molecule family (SLAMF) members act as microbial sensors and modulate immune functions in response to infection. Here, human blood transcriptomic analyses reveal the involvement of SLAMF7 and SLAMF8 in many infectious diseases, with elevated levels associated with type I IFN responses in salmonellosis and brucellosis patients. We further identify SLAMF7 and SLAMF8 as key regulators of human pDC function. They activate pDC maturation and cytokine production during infection with bacteria that induce acute (Salmonella) or chronic (Brucella) inflammation. SLAMF7 and SLAMF8 signal through NF-κB, IRF7, and STAT-1, and limit mitochondrial ROS accumulation upon Salmonella infection. Remarkably, this SLAMF7/8-dependent control of mitochondrial ROS levels favors bacterial persistence and NF-κB activation. Overall, our results unravel essential shared multifaceted roles of SLAMF7 and SLAMF8 in finely tuning human pDC responses to intracellular bacterial infections with potential for future diagnostic and therapeutic applications.
Authors
Joaquín Miguel Pellegrini, Anne Keriel, Laurent Gorvel, Sean Hanniffy, Vilma Arce-Gorvel, Mile Bosilkovski, Javier Solera, Stéphane Méresse, Sylvie Mémet, Jean-Pierre Gorvel
×Abstract
Hepatic insulin resistance is central to type 2 diabetes (T2D) and metabolic syndrome, but defining the molecular basis of this defect in humans is challenging because of limited tissue access. Utilizing inducible pluripotent stem cells differentiated into hepatocytes from control individuals and patients with T2D and liquid chromatography with tandem mass spectrometry–based (LC-MS/MS–based) phosphoproteomics analysis, we identified a large network of cell-intrinsic alterations in signaling in T2D. Over 300 phosphosites showed impaired or reduced insulin signaling, including losses in the classical insulin-stimulated PI3K/AKT cascade and their downstream targets. In addition, we identified over 500 phosphosites of emergent, i.e., new or enhanced, signaling. These occurred on proteins involved in the Rho-GTPase pathway, RNA metabolism, vesicle trafficking, and chromatin modification. Kinome analysis indicated that the impaired phosphorylation sites represented reduced actions of AKT2/3, PKCθ, CHK2, PHKG2, and/or STK32C kinases. By contrast, the emergent phosphorylation sites were predicted to be mediated by increased action of the Rho-associated kinases 1 and 2 (ROCK1/2), mammalian STE20-like protein kinase 4 (MST4), and/or branched-chain α-ketoacid dehydrogenase kinase (BCKDK). Inhibiting ROCK1/2 activity in T2D induced pluripotent stem cell–derived hepatocytes restored some of the alterations in insulin action. Thus, insulin resistance in the liver in T2D did not simply involve a loss of canonical insulin signaling but the also appearance of new phosphorylations representing a change in the balance of multiple kinases. Together, these led to altered insulin action in the liver and identified important targets for the therapy of hepatic insulin resistance.
Authors
Arijeet K. Gattu, Maria Tanzer, Tomer M. Yaron-Barir, Jared L. Johnson, Ashok Kumar Jayavelu, Hui Pan, Jonathan M. Dreyfuss, Lewis C. Cantley, Matthias Mann, C. Ronald Kahn
×Abstract
Serotonin (5-HT) is a neurotransmitter that has been linked to tumorigenesis. Whether and how 5-HT modulates cells in the microenvironment to regulate tumor metastasis is largely unknown. Here, we demonstrate that 5-HT was secreted by neuroendocrine prostate cancer (NEPC) cells to communicate with neutrophils and to induce the formation of neutrophil extracellular traps (NETs) in the liver, which in turn facilitated the recruitment of disseminated cancer cells and promoted liver metastasis. 5-HT induced histone serotonylation (H3Q5ser) and orchestrated histone citrullination (H3cit) in neutrophils to trigger chromatin decondensation and facilitate the formation of NETs. Interestingly, we uncovered in this process a reciprocally reinforcing effect between H3Q5ser and H3cit and a crosstalk between the respective writers enzyme transglutaminase 2 (TGM2) and peptidylarginine deiminase 4 (PAD4). Genetic ablation or pharmacological targeting of TGM2, or inhibition of the 5-HT transporter (SERT) with the FDA-approved antidepressant drug fluoxetine reduced H3Q5ser and H3cit modifications, suppressed NET formation, and effectively inhibited NEPC, small-cell lung cancer, and thyroid medullary cancer liver metastasis. Collectively, the 5-HT–triggered production of NETs highlights a targetable neurotransmitter/immune axis that drives liver metastasis of NE cancers.
Authors
Kaiyuan Liu, Yingchao Zhang, Genyu Du, Xinyu Chen, Lingling Xiao, Luyao Jiang, Na Jing, Penghui Xu, Chaoxian Zhao, Yiyun Liu, Huifang Zhao, Yujiao Sun, Jinming Wang, Chaping Cheng, Deng Wang, Jiahua Pan, Wei Xue, Pengcheng Zhang, Zhi-Gang Zhang, Wei-Qiang Gao, Shu-Heng Jiang, Kai Zhang, Helen He Zhu
×Abstract
Induction of durable protective immune responses is the main goal of prophylactic vaccines, and adjuvants play a role as drivers of such responses. Despite advances in vaccine strategies, development of a safe and effective HIV vaccine remains a significant challenge. Use of an appropriate adjuvant is crucial to the success of HIV vaccines. Here we assessed the saponin/MPLA nanoparticle (SMNP) adjuvant with an HIV envelope (Env) trimer, evaluating the safety and effect of multiple variables — including adjuvant dose (16-fold dose range), immunization route, and adjuvant composition — on the establishment of Env-specific memory T and B cell (TMem and BMem) responses and long-lived plasma cells in nonhuman primates (NHPs). Robust BMem were detected in all groups, but a 6-fold increase was observed in the highest- versus the lowest-SMNP-dose group. Similarly, stronger vaccine responses were induced by the highest SMNP dose in CD40L+OX40+ CD4+ TMem (11-fold), IFN-γ+ CD4+ TMem (15-fold), IL21+ CD4+ TMem (9-fold), circulating T follicular helper cells (TFH; 3.6-fold), BM plasma cells (7-fold), and binding IgG (1.3-fold). Substantial tier 2 neutralizing antibodies were only observed in the higher-SMNP-dose groups. These investigations highlight the dose-dependent potency of SMNP and its relevance for human use and next-generation vaccines.
Authors
Parham Ramezani-Rad, Ester Marina-Zárate, Laura Maiorino, Amber Myers, Katarzyna Kaczmarek Michaels, Ivan S. Pires, Nathaniel I. Bloom, Mariane B. Melo, Ashley A. Lemnios, Paul G. Lopez, Christopher A. Cottrell, Iszac Burton, Bettina Groschel, Arpan Pradhan, Gabriela Stiegler, Magdolna Budai, Daniel Kumar, Sam Pallerla, Eddy Sayeed, Sangeetha L. Sagar, Sudhir Pai Kasturi, Koen K.A. Van Rompay, Lars Hangartner, Andreas Wagner, Dennis R. Burton, William R. Schief, Shane Crotty, Darrell J. Irvine
×Abstract
Colorectal cancer (CRC) remains a leading cause of cancer death because of metastatic spread. LIN28B is overexpressed in 30% of CRCs and promotes metastasis, yet its mechanisms remain unclear. In this study, we genetically modified CRC cell lines to overexpress LIN28B, resulting in enhanced PI3K/AKT pathway activation and liver metastasis in mice. We developed genetically modified mouse models with constitutively active Pik3ca that form intestinal tumors progressing to liver metastases with an intact immune system, addressing the limitations of previous Pik3ca-mutant models, including long tumor latency, mixed histology, and lack of distant metastases. The PI3Kα-specific inhibitor alpelisib reduced migration and invasion in vitro and metastasis in vivo. We present a comprehensive analysis of vertical inhibition of the PI3K/AKT pathway in CRC using the FDA-approved drugs alpelisib and capivasertib (an AKT inhibitor) in combination with LY2584702 (a ribosomal protein S6 kinase inhibitor) in CRC cell lines and mouse- and patient-derived organoids. Tissue microarrays from patients with CRC verified that LIN28B and PI3K/AKT pathway activation correlate with CRC progression. These findings highlight the critical role of the LIN28B-mediated PI3K/AKT pathway in CRC metastasis, the therapeutic potential of targeted inhibition, and the promise of patient-derived organoids in precision medicine in metastatic CRC.
Authors
Alice E. Shin, Kensuke Sugiura, Secunda W. Kariuki, David A. Cohen, Samuel P. Flashner, Andres J. Klein-Szanto, Noriyuki Nishiwaki, Dechokyab De, Neil Vasan, Joel T. Gabre, Christopher J. Lengner, Peter A. Sims, Anil K. Rustgi
×Abstract
Tumor cells often employ many ways to restrain type I IFN signaling to evade immune surveillance. However, whether cellular amino acid metabolism regulates this process remains unclear, and its effects on antitumor immunity are relatively unexplored. Here, we found that asparagine inhibited IFN-I signaling and promoted immune escape in bladder cancer. Depletion of asparagine synthetase (ASNS) strongly limited in vivo tumor growth in a CD8+ T cell–dependent manner and boosted immunotherapy efficacy. Moreover, clinically approved L-asparaginase (ASNase),synergized with anti–PD-1 therapy in suppressing tumor growth. Mechanistically, asparagine can directly bind to RIG-I and facilitate CBL-mediated RIG-I degradation, thereby suppressing IFN signaling and antitumor immune responses. Clinically, tumors with higher ASNS expression show decreased responsiveness to immune checkpoint inhibitor therapy. Together, our findings uncover asparagine as a natural metabolite to modulate RIG-I–mediated IFN-I signaling, providing the basis for developing the combinatorial use of ASNase and anti–PD-1 for bladder cancer.
Authors
Wenjie Wei, Hongzhao Li, Shuo Tian, Chi Zhang, Junxiao Liu, Wen Tao, Tianwei Cai, Yuhao Dong, Chuang Wang, Dingyi Lu, Yakun Ai, Wanlin Zhang, Hanfeng Wang, Kan Liu, Yang Fan, Yu Gao, Qingbo Huang, Xin Ma, Baojun Wang, Xu Zhang, Yan Huang
×Abstract
BACKGROUND Current methods for detecting esophageal cancer (EC) are generally invasive or exhibit limited sensitivity and specificity, especially for the identification of early-stage tumors.METHODS We identified potential methylated DNA markers (MDMs) from multiple genomic regions in a discovery cohort, and a diagnostic model was developed and verified in a model-verification cohort of 297 participants. The accuracy of the MDM panel was validated in a multicenter, prospective cohort (n = 1,429). The clinical performance of identified MDMs were compared with current tumor-associated protein markers.RESULTS From 31 significant differentially methylated EC-associated regions identified in the marker discovery, we trained and validated a 3-MDM diagnostic model that could discriminate among patients with EC and volunteers without EC in a multicenter clinical prospective cohort with a sensitivity of 85.5% and a specificity of 95.3%. This panel showed higher sensitivity in diagnosing early-stage tumors, with sensitivities of 56% for stage 0 and 77% for stage I, compared with the performance of current biochemical markers. In population with high risk for EC, the sensitivity and specificity were 85.68% and 93.61%, respectively.CONCLUSION The assessment of tumor-associated methylation status in blood samples can facilitate noninvasive and reliable diagnosis of early-stage EC, which warrants further development to expand screening and reduce mortality rates.TRIAL REGISTRATION ChiCTR2400083525.FUNDING Science and technology funds of Beijing Municipal Science & Technology Commission, Administrative Commission of Zhongguancun Science Park. Project number: Z201100005420007.
Authors
Ruixiang Zhang, Yongzhan Nie, Xiaobing Chen, Tao Jiang, Jinhai Wang, Yuhui Peng, Guangpeng Zhou, Yong Li, Lina Zhao, Beibei Chen, Yunfeng Ni, Yan Cheng, Yiwei Xu, Zhenyu Zhu, Xianchun Gao, Zhen Wu, Tianbao Li, Jie Zhao, Cantong Liu, Gang Zhao, Jiakuan Chen, Jing Zhao, Gang Ji, Xiaoliang Han, Jie He, Yin Li
×Abstract
Shwachman-Diamond syndrome (SDS) is characterized by neutropenia, exocrine pancreatic insufficiency, and bony abnormalities with an increased risk of myeloid neoplasia. Almost all cases of SDS result from biallelic mutations in Shwachman-Bodian-Diamond syndrome (SBDS). SBDS interacts with elongation factor–like 1 (EFL1) to displace eukaryotic initiation factor 6 (EIF6) from the 60S ribosomal subunit. Released EIF6 permits the assembly of ribosomal large and small subunits in the cytoplasm. Decreased EIF6 levels due to haploinsufficiency or missense mutations, which lead to decreased protein expression, may provide a somatic genetic rescue and antileukemic effects. We observed accumulation of EIF6 protein in sbds-KO zebrafish models, confirmed this accumulation in patient-derived tissues, and correlated these with changes in ribosomal proteins and tumor protein p53 (TP53) pathways. The mechanism of action for this adaptive response is unknown. To address this, we generated eif6-KO zebrafish, which do not survive more than 10 days after fertilization. We also created 2 mutants with low Eif6 expression, i.e., 5%–25% of WT levels, that could survive until adulthood. We bred them with sbds-null strains and analyzed their phenotype and biochemical properties. Low Eif6 levels reduced Tp53 pathway activation but did not rescue neutropenia in Sbds-deficient zebrafish. Further studies elucidating the interplay between SBDS, EIF6, and TP53 and cellular stress responses offer promising insights into SDS pathogenesis, somatic genetic rescue, and therapeutic strategies.
Authors
Usua Oyarbide, Valentino Bezzerri, Morgan Staton, Christian Boni, Arish Shah, Marco Cipolli, Eliezer Calo, Seth J. Corey
×Abstract
Spontaneous clearance of hepatitis B virus (HBV) is frequent in adults (95%) but rare in infants (5%), emphasizing the critical role of age-related hepatic immunocompetence. However, the underlying mechanisms of hepatocyte-specific immunosurveillance and age-dependent HBV clearance remain unclear. Here, we identified PGLYRP2 as a hepatocyte-specific pattern recognition receptor with age-dependent expression, and demonstrated that phase separation of PGLYRP2 was a critical driver of spontaneous HBV clearance in hepatocytes. Mechanistically, PGLYRP2 recognized and potentially eliminated covalently closed circular DNA via phase separation, coordinated by its intrinsically disordered region and HBV DNA-binding domain (PGLYRP2IDR/209–377) in the nucleus. Additionally, PGLYRP2 suppressed HBV capsid assembly by directly interacting with the viral capsid, mediated by its PGRP domain. This interaction promoted the nucleocytoplasmic translocation of PGLYRP2 and subsequent secretion of the PGLYRP2/HBV capsid complex, thereby bolstering the hepatic antiviral response. Pathogenic variants or deletions in PGLYRP2 impaired its ability to inhibit HBV replication, highlighting its essential role in hepatocyte-intrinsic immunity. These findings suggest that targeting the PGLYRP2-mediated host-virus interaction may offer a potential therapeutic strategy for the development of anti-HBV treatments, representing a promising avenue for achieving a functional cure for HBV infection.
Authors
Ying Li, Huihui Ma, Yongjian Zhang, Tinghui He, Binyang Li, Haoran Ren, Jia Feng, Jie Sheng, Kai Li, Yu Qian, Yunfeng Wang, Haoran Zhao, Jie He, Huicheng Li, Hongjin Wu, Yuanfei Yao, Ming Shi
×Abstract
Newly produced platelets acquire a low activation state, but whether the megakaryocyte plays a role in this outcome has not been fully uncovered. Mesenchymal stem cells (MSCs) were previously shown to promote platelet production and lower platelet activation. We found that healthy megakaryocytes transfer mitochondria to MSCs, which is mediated by connexin 43 (Cx43) gap junctions on MSCs and leads to platelets at a low energetic state with increased LYN activation, characteristic of resting platelets with increased LYN activation, characteristic of resting platelets. On the contrary, MSCs have a limited ability to transfer mitochondria to megakaryocytes. Sickle cell disease (SCD) is characterized by hemolytic anemia and results in heightened platelet activation, contributing to numerous disease complications. Platelets in SCD mice and human samples had a heightened energetic state with increased glycolysis. MSC exposure to heme in SCD led to decreased Cx43 expression and a reduced ability to uptake mitochondria from megakaryocytes. This prevented LYN activation in platelets and contributed to increased platelet activation at steady state. Altogether, our findings demonstrate an effect of hemolysis in the microenvironment leading to increased platelet activation in SCD. These findings have the potential to inspire new therapeutic targets to relieve thrombosis-related complications of SCD and other hemolytic conditions.
Authors
Chengjie Gao, Yitian Dai, Paul A. Spezza, Paul Boasiako, Alice Tang, Giselle Rasquinha, Hui Zhong, Bojing Shao, Yunfeng Liu, Patricia A. Shi, Cheryl A. Lobo, Xiuli An, Anqi Guo, William B. Mitchell, Deepa Manwani, Karina Yazdanbakhsh, Avital Mendelson
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Abstract
The progression of metabolic dysfunction-associated steatotic liver disease (MASLD) to metabolic dysfunction-associated steatohepatitis (MASH) involves alterations in both liver-autonomous and systemic metabolism that influence the liver’s balance of fat accretion and disposal. Here, we quantify the contributions of hepatic oxidative pathways to liver injury in MASLD-MASH. Using NMR spectroscopy, UHPLC-MS, and GC-MS, we performed stable-isotope tracing and formal flux modeling to quantify hepatic oxidative fluxes in humans across the spectrum of MASLD-MASH, and in mouse models of impaired ketogenesis. In humans with MASH, liver injury correlated positively with ketogenesis and total fat oxidation, but not with turnover of the tricarboxylic acid cycle. Loss-of-function mouse models demonstrated that disruption of mitochondrial HMG-CoA synthase (HMGCS2), the rate-limiting step of ketogenesis, impairs overall hepatic fat oxidation and induces a MASLD-MASH-like phenotype. Disruption of mitochondrial β-hydroxybutyrate dehydrogenase (BDH1), the terminal step of ketogenesis, also impaired fat oxidation, but surprisingly did not exacerbate steatotic liver injury. Taken together, these findings suggest that quantifiable variations in overall hepatic fat oxidation may not be a primary determinant of MASLD-to-MASH progression, but rather, that maintenance of ketogenesis could serve a protective role through additional mechanisms that extend beyond overall rates of fat oxidation.
Authors
Eric D. Queathem, David B. Stagg, Alisa B. Nelson, Alec B. Chaves, Scott B. Crown, Kyle Fulghum, D. Andre d'Avignon, Justin R. Ryder, Patrick J. Bolan, Abdirahman Hayir, Jacob R. Gillingham, Shannon Jannatpour, Ferrol I. Rome, Ashley S. Williams, Deborah M. Muoio, Sayeed Ikramuddin, Curtis C. Hughey, Patrycja Puchalska, Peter A. Crawford
Abstract
Patients with systemic lupus erythematosus (SLE) are photosensitive, developing skin inflammation with even ambient ultraviolet radiation (UVR), and this cutaneous photosensitivity can be associated with UVR-induced flares of systemic disease, which can involve increased autoantibodies and further end organ injury. Mechanistic insight into the link between the skin responses and autoimmunity is limited. Signals from skin are transmitted directly to the immune system via lymphatic vessels, and here we show evidence for potentiation of UVR-induced lymphatic flow dysfunction in SLE patients and murine models. Improving lymphatic flow by manual lymphatic drainage (MLD) or with a transgenic model with increased lymphatic vessels reduces both cutaneous inflammation and lymph node B and T cell responses, and long term MLD reduces splenomegaly and titers of a number of autoantibodies. Mechanistically, improved flow restrains B cell responses in part by stimulating a lymph node fibroblastic reticular cell-monocyte axis. Our results point to lymphatic modulation of lymph node stromal function as a link between photosensitive skin responses and autoimmunity and as a therapeutic target in lupus, provide insight into mechanisms by which the skin state regulates draining lymph node function, and suggest the possibility of MLD as an accessible and cost-effective adjunct to add to ongoing medical therapies for lupus and related diseases.
Authors
Mir J. Howlader, William G. Ambler, Madhavi Latha S. Chalasani, Aahna Rathod, Ethan S. Seltzer, Ji Hyun Sim, Jinyeon Shin, Noa Schwartz, William D. Shipman III, Dragos C. Dasoveanu, Camila B. Carballo, Ecem Sevim, Salma Siddique, Yurii Chinenov, Scott A. Rodeo, Doruk Erkan, Raghu P. Kataru, Babak J. Mehrara, Theresa T. Lu
Abstract
As antimicrobial resistance rises, new antibacterial candidates are urgently needed. Using sequence space information from over 14,743 functional antimicrobial peptides (AMPs), we improved the antimicrobial properties of citropin 1.1, an AMP with weak anti-methicillin resistant Staphylococcus aureus (MRSA) activity, producing a short and potent anti-staphylococcal peptide, CIT-8 (13 residues). At 40 μg/ml, CIT-8 eradicated 1 × 108 drug-resistant MRSA and VRSA (vancomycin resistant S. aureus) persister cells within 30 mins of exposure and reduced the number of viable biofilm cells of MRSA and VRSA by 3 log10 and 4 log10 in established biofilms, respectively. CIT-8 (at 32 μg/ml) depolarized and permeated the S. aureus MW2 membrane. In a mouse model of MRSA skin infection, CIT-8 (2% w/w in petroleum jelly) significantly reduced the bacterial burden by 2.3 log10 (p < 0.0001). Our methodology accelerates AMP design by combining traditional peptide design strategies, such as truncation, substitution, and structure-guided alteration, with machine learning (ML)-backed sequence optimization.
Authors
Biswajit Mishra, Anindya Basu, Fadi Shehadeh, LewisOscar Felix, Sai Sundeep Kollala, Yashpal Singh Chhonker, Mandar T. Naik, Charilaos Dellis, Liyang Zhang, Narchonai Ganesan, Daryl J. Murry, Jianhua Gu, Michael B. Sherman, Frederick M. Ausubel, Paul P. Sotiriadis, Eleftherios Mylonakis
Abstract
BACKGROUND. Adipose tissue-derived endotrophin, a peptide cleaved from the α3 chain of collagen VI during fibrogenesis, causes systemic insulin resistance in rodent models. Here, we evaluated the potential importance of endotrophin in regulating whole-body insulin sensitivity in people. METHODS. We evaluated: i) plasma endotrophin concentration, insulin sensitivity (assessed by using the hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled glucose tracer infusion) and adipose tissue expression of genes involved in endotrophin production in three groups of participants that were rigorously stratified by adiposity and insulin sensitivity [lean insulin-sensitive (Lean-IS; n=10), obese insulin-sensitive (Obese-IS; n=10), and obesity insulin-resistant (Obese-IR; n=10)]; ii) plasma endotrophin concentration and insulin sensitivity in 15 people with obesity and type 2 diabetes before and after marked (~18%) weight loss; and iii) the effect of endotrophin on insulin signaling (AKTser473 phosporylation) and insulin action (insulin-stimulated glucose uptake) in primary human skeletal muscle myotubes. RESULTS. Plasma endotrophin progressively increased from the Lean-IS to the Obese-IS to the Obese-IR group, was negatively associated with insulin sensitivity and positively associated with factors involved in adipose tissue endotrophin production, namely adipose tissue gene expression of matrix metalloproteinases and markers of hypoxia, inflammation, and fibrosis. Marked weight loss increased insulin sensitivity in conjunction with a decrease in plasma endotrophin concentration. Endotrophin inhibited insulin insulin-stimulated AKTser473 phosphorylation and insulin-stimulated glucose uptake in myotubes, which was restored by incubation with a neutralizing endotrophin antibody. CONCLUSIONS. These results suggest plasma endotrophin is both a biomarker and cause of whole-body insulin resistance in people with obesity.
Authors
Gordon I. Smith, Samuel Klein
Abstract
Colistin (COL) is a cationic cyclic peptide that disrupts negatively-charged Gram-negative bacterial cell membranes and frequently serves as an antibiotic of last resort to combat multidrug-resistant Gram-negative bacterial infections. Emergence of the horizontally transferable plasmid-borne mobilized colistin resistance (mcr) determinant and its spread to Gram-negative strains harboring extended-spectrum β-lactamase and carbapenemase resistance genes threatens futility of our chemotherapeutic arsenal. COL is widely regarded to have zero activity against mcr+ strains based on standard antimicrobial susceptibility testing (AST) performed in enriched bacteriological growth media; consequently, the drug is withheld from patients with mcr+ infections. However, these standard testing media poorly mimic in vivo physiology and omit host immune factors. Here we observed that COL exhibits bactericidal activities against mcr+ isolates of Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica in tissue culture media containing the physiological buffer bicarbonate. Moreover, COL promoted serum complement deposition on the mcr-1+ Gram-negative bacterial surface and synergized potently with active human serum in pathogen killing. At COL concentrations readily achievable with standard dosing, the peptide antibiotic killed mcr-1+ E. coli, K. pneumoniae, and S. enterica in freshly isolated human blood and proved effective as monotherapy in a murine model of E. coli bacteremia. Our results suggest that COL, currently ignored as a treatment option based on traditional AST, may in fact benefit patients with mcr-1+ Gram negative infections based on evaluations performed in a more physiologic context. These concepts warrant careful consideration in the clinical microbiology laboratory and for future clinical investigation of their merits in high-risk patients with limited therapeutic options.
Authors
Monika Kumaraswamy, Angelica Riestra, Anabel Flores, Samira Dahesh, Fatemeh Askarian, Satoshi Uchiyama, Jonathan Monk, Sean Jung, Gunnar Bondsäter, Victoria Nilsson, Melanie Chang, Jürgen B Bulitta, Yinzhi Lang, Armin Kousha, Elisabet Bjånes, Natalie Chavarria, Ty'Tianna Clark, Hideya Seo, George Sakoulas, Victor Nizet
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Series edited by Scott L. Friedman
Evolving insights into MASLD and MASH pathogenesis and treatment
Series edited by Scott L. Friedman
Metabolic dysfunction associated steatotic liver disease (MASLD, formerly called NAFLD) and its more advanced form, metabolic dysfunction associated steatohepatitis (MASH, formerly called NASH) are increasing in prevalence worldwide as the number of individuals with metabolic risk factors rises. These diseases and their adverse sequelae have a formidable economic impact, and there remain large gaps in understanding and treating MASLD/MASH. Series editor Scott Friedman curated this series of expert-led review articles to cover advances and challenges across the spectrum of basic investigation to clinical trials. The reviews will address diagnostic approaches, management strategies specific to adolescent and pregnant individuals, pathobiology, and therapeutic horizons, with the goal of reflecting the heterogeneity seen in disease drivers as well as the affected population.
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Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)