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Erythrocyte-derived extracellular vesicles induce endothelial dysfunction through arginase-1 and oxidative stress in type 2 diabetes

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Abstract

Red blood cells (RBCs) induce endothelial dysfunction in type 2 diabetes (T2D), but the mechanism by which RBCs communicate with the vessel is unknown. This study tested the hypothesis that extracellular vesicles (EVs) secreted by RBCs act as mediators of endothelial dysfunction in T2D. Despite a lower production of EVs derived from RBCs of T2D patients (T2D RBC-EVs), their uptake by endothelial cells was greater than that of EVs derived from RBCs of healthy individuals (H RBC-EVs). T2D RBC-EVs impaired endothelium-dependent relaxation and this effect was attenuated following inhibition of arginase in EVs. Inhibition of vascular arginase or oxidative stress also attenuated endothelial dysfunction induced by T2D RBC-EVs. Arginase-1 was detected in RBC-derived EVs, and arginase-1 and oxidative stress were increased in endothelial cells following co-incubation with T2D RBC-EVs. T2D RBC-EVs also increased arginase-1 protein in endothelial cells following mRNA silencing and in the endothelium of aortas from endothelial cell arginase 1 knockout mice. It is concluded that T2D-RBCs induce endothelial dysfunction through increased uptake of EVs that transfer arginase-1 from RBCs to the endothelium to induce oxidative stress and endothelial dysfunction. These results shed important light on the mechanism underlying endothelial injury mediated by RBCs in T2D.

Authors

Aida Collado, Rawan Humoud, Eftychia Kontidou, Maria Eldh, Jasmin Swaich, Allan Zhao, Jiangning Yang, Tong Jiao, Elena Domingo, Emelie Carlestål, Ali Mahdi, John Tengbom, Ákos Végvári, Qiaolin Deng, Michael Alvarsson, Susanne Gabrielsson, Per Eriksson, Zhichao Zhou, John Pernow

TP53 mutations and TET2 deficiency cooperate to drive leukemogenesis and establish an immunosuppressive environment

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Abstract

Mutations and deletions in TP53 are associated with adverse outcomes in patients with myeloid malignancies and developing improved therapies for TP53-mutant leukemias is of urgent need. Here we identify mutations in TET2 as the most common co-occurring mutation in TP53 mutant acute myeloid leukemia (AML) patients. In mice, combined hematopoietic-specific deletion of TET2 and TP53 resulted in enhanced self-renewal compared to deletion of either gene alone. Tp53/Tet2 double knockout mice developed serially transplantable AML. Both mice and AML patients with combined TET2/TP53 alterations upregulated innate immune signaling in malignant granulocyte-monocyte progenitors (GMPs), which had leukemia-initiating capacity. A20 governs the leukemic maintenance by triggering aberrant non-canonical NF-κB signaling. Mice with Tp53/Tet2 loss had expansion of monocytic myeloid-derived suppressor cells (MDSCs), which impaired T cell proliferation and activation. Moreover, mice and AML patients with combined TP53/TET2 alterations displayed increased expression of the TIGIT ligand, CD155, on malignant cells. TIGIT blocking antibodies augmented NK cell-mediated killing of Tp53/Tet2 double-mutant AML cells, reduced leukemic burden, and prolonged survival in Tp53/Tet2 double knockout mice. These findings uncover a leukemia-promoting link between TET2 and TP53 mutations and highlight therapeutic strategies to overcome the immunosuppressive bone marrow environment in this adverse subtype of AML.

Authors

Pu Zhang, Ethan C. Whipp, Sarah J. Skuli, Mehdi Gharghabi, Caner Saygin, Steven A. Sher, Martin Carroll, Xiangyu Pan, Eric D. Eisenmann, Tzung-Huei Lai, Bonnie K. Harrington, Wing Keung Chan, Youssef Youssef, Bingyi Chen, Alex Penson, Alexander M. Lewis, Cynthia R. Castro, Nina Fox, Ali Cihan, Jean-Benoit Le Luduec, Susan DeWolf, Tierney Kauffman, Alice S. Mims, Daniel Canfield, Hannah Phillips, Katie E. Williams, Jami Shaffer, Arletta Lozanski, Tzyy-Jye Doong, Gerard Lozanski, Charlene Mao, Christopher J. Walker, James S. Blachly, Anthony F. Daniyan, Lapo Alinari, Robert A. Baiocchi, Yiping Yang, Nicole R. Grieselhuber, Moray J. Campbell, Sharyn D. Baker, Bradley W. Blaser, Omar Abdel-Wahab, Rosa Lapalombella

Disrupted Minor Intron Splicing Activates Reductive Carboxylation-mediated Lipogenesis to Drive Metabolic Dysfunction-associated Steatotic Liver Disease Progression

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Abstract

Aberrant RNA splicing is tightly linked to diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we revealed that minor intron splicing, a unique and conserved RNA processing event, is largely disrupted upon the progression of metabolic dysfunction-associated steatohepatitis (MASH) in mice and humans. We demonstrated deficiency of minor intron splicing in the liver induces MASH transition upon obesity-induced insulin resistance and LXR activation. Mechanistically, inactivation of minor intron splicing leads to minor intron retention of Insig1 and Insig2, resulting in premature termination of translation, which drives proteolytic activation of SREBP1c. This mechanism is conserved in human patients with MASH. Notably, disrupted minor intron splicing activates glutamine reductive metabolism for de novo lipogenesis through the induction of Idh1, which causes the accumulation of ammonia in the liver, thereby initiating hepatic fibrosis upon LXR activation. Ammonia clearance or IDH1 inhibition blocks hepatic fibrogenesis and mitigates MASH progression. More importantly, the overexpression of Zrsr1 restored minor intron retention and ameliorated the development of MASH, indicating that dysfunctional minor intron splicing is an emerging pathogenic mechanism that drives MASH progression. Additionally, reductive carboxylation flux triggered by minor intron retention in hepatocytes serves as a crucial checkpoint and potential target for MASH therapy.

Authors

Yinkun Fu, Xin Peng, Hongyong Song, Xiaoyun Li, Yang Zhi, Jieting Tang, Yifan Liu, Ding Chen, Wenyan Li, Jing Zhang, Jing Ma, Ming He, Yimin Mao, Xu-Yun Zhao

Absence of intracellular lipolytic inhibitor G0S2 enhances intravascular triglyceride clearance and abolishes diet-induced hypertriglyceridemia

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Abstract

The interplay between intracellular and intravascular lipolysis is crucial for maintaining circulating lipid levels and systemic energy homeostasis. Adipose triglyceride lipase (ATGL) and lipoprotein lipase (LPL), the primary triglyceride (TG) lipases responsible for these two spatially separate processes, are highly expressed in adipose tissue. Yet, their coordinated regulation remains undetermined. Here, we demonstrate that genetic ablation of G0S2, a specific inhibitory protein of ATGL, completely abolishes diet-induced hypertriglyceridemia and significantly attenuates atherogenesis in mice. These effects are attributed to enhanced whole-body TG clearance, not altered hepatic TG secretion. Specifically, G0S2 deletion increases circulating LPL concentration and activity, predominantly through LPL production from white adipose tissue (WAT). Strikingly, transplantation of G0S2-deficient WAT normalizes plasma TG levels in mice with hypertriglyceridemia. In conjunction with improved insulin sensitivity and decreased ANGPTL4 expression, the absence of G0S2 enhances the stability of LPL protein in adipocytes, a phenomenon that can be reversed upon ATGL inhibition. Collectively, these findings highlight the pivotal role of adipocyte G0S2 in regulating both intracellular and intravascular lipolysis, and the possibility of targeting G0S2 as a viable pharmacological approach to reduce circulating TGs.

Authors

Yongbin Chen, Scott M. Johnson, Stephanie D. Burr, Davide Povero, Aaron M. Anderson, Cailin E. McMahon, Jun Liu

Maintenance of graft tissue-resident Foxp3⁺ cells is necessary for lung transplant tolerance in mice

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Abstract

Mechanisms that mediate allograft tolerance differ between organs. We have previously shown that Foxp3+ T cell-enriched bronchus-associated lymphoid tissue (BALT) is induced in tolerant murine lung allografts and that these Foxp3+ cells suppress alloimmune responses locally and systemically. Here, we demonstrated that Foxp3+ cells that reside in tolerant lung allografts differed phenotypically and transcriptionally from those in the periphery and were clonally expanded. Using a mouse lung re-transplant model, we showed that recipient Foxp3+ cells were continuously recruited to the BALT within tolerant allografts. We identified distinguishing features of graft-resident and newly recruited Foxp3+ cells and showed that graft-infiltrating Foxp3+ cells acquired transcriptional profiles resembling those of graft-resident Foxp3+ cells over time. Allografts underwent combined antibody-mediated rejection (AMR) and acute cellular rejection (ACR) when recruitment of recipient Foxp3+ cells was prevented. Finally, we showed that local administration of IL-33 could expand and activate allograft-resident Foxp3+ cells providing a platform for the design of tolerogenic therapies for lung transplant recipients. Our findings establish graft-resident Foxp3+ cells as critical orchestrators of lung transplant tolerance and highlight the need to develop lung-specific immunosuppression.

Authors

Wenjun Li, Yuriko Terada, Yun Zhu Bai, Yuhei Yokoyama, Hailey M. Shepherd, Junedh M. Amrute, Amit I. Bery, Zhiyi Liu, Jason M. Gauthier, Marina Terekhova, Ankit Bharat, Jon H. Ritter, Varun Puri, Ramsey R. Hachem, Hēth R. Turnquist, Peter T. Sage, Alessandro Alessandrini, Maxim N. Artyomov, Kory J. Lavine, Ruben G. Nava, Alexander S. Krupnick, Andrew E. Gelman, Daniel Kreisel

Differential aortic aneurysm formation provoked by chemogenetic oxidative stress

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Abstract

Aortic aneurysms are potentially fatal focal enlargements of the aortic lumen; the disease burden disease is increasing as the human population ages. Pathological oxidative stress is implicated in development of aortic aneurysms. We pursued a chemogenetic approach to create an animal model of aortic aneurysm formation using a transgenic mouse line DAAO-TGTie2 that expresses yeast D-amino acid oxidase (DAAO) under control of the endothelial Tie2 promoter. In DAAO-TGTie2 mice, DAAO generates the reactive oxygen species hydrogen peroxide (H2O2) in endothelial cells only when provided with D-amino acids. When DAAO-TGTie2 mice are chronically fed D-alanine, the animals become hypertensive and develop abdominal but not thoracic aortic aneurysms. Generation of H2O2 in the endothelium leads to oxidative stress throughout the vascular wall. Proteomic analyses indicate that the oxidant-modulated protein kinase JNK1 is dephosphorylated by the phophoprotein phosphatase DUSP3 in abdominal but not thoracic aorta, causing activation of KLF4-dependent transcriptional pathways that trigger phenotypic switching and aneurysm formation. Pharmacological DUSP3 inhibition completely blocks aneurysm formation caused by chemogenetic oxidative stress. These studies establish that regional differences in oxidant-modulated signaling pathways lead to differential disease progression in discrete vascular beds, and identify DUSP3 as a potential pharmacological target for the treatment of aortic aneurysms.

Authors

Apabrita Ayan Das, Markus Waldeck-Weiermair, Shambhu Yadav, Fotios Spyropoulos, Arvind Pandey, Tanoy Dutta, Taylor A. Covington, Thomas Michel

Reactivation of CTLA4-expressing T cells Accelerates Resolution of Lung Fibrosis in a Humanized Mouse Model

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Abstract

Tissue regenerative responses involve complex interactions between resident structural and immune cells. Recent reports indicate that accumulation of senescent cells during injury repair contributes to pathological tissue fibrosis. Using tissue-based spatial transcriptomics and proteomics, we identified upregulation of the immune checkpoint protein, cytotoxic T-lymphocyte associated protein 4 (CTLA4) on CD8+ T cells adjacent to regions of active fibrogenesis in human idiopathic pulmonary fibrosis (IPF) and in a murine model of repetitive bleomycin lung injury model of persistent fibrosis. In humanized CTLA4 knock-in mice, treatment with ipilimumab, an FDA-approved drug that targets CTLA4, resulted in accelerated lung epithelial regeneration and diminished fibrosis from repetitive bleomycin injury. Ipilimumab treatment resulted in the expansion of Cd3e+ T cells, diminished accumulation of senescent cells, and robust expansion of type 2 alveolar epithelial cells, facultative progenitor cells of the alveolar epithelium. Ex-vivo activation of isolated CTLA4-expressing CD8+ cells from mice with established fibrosis resulted in enhanced cytolysis of senescent cells, suggesting that impaired immune-mediated clearance of these cells contribute to persistence of lung fibrosis in this murine model. Our studies support the concept that endogenous immune surveillance of senescent cells may be essential in promoting tissue regenerative responses that facilitate the resolution of fibrosis.

Authors

Santosh Yadav, Muralidharan Anbalagan, Shamima Khatun, Devadharshini Prabhakaran, Justin Manges, Yasuka Matsunaga, James B. McLachlan, Joseph A. Lasky, Jay Kolls, Victor J. Thannickal

AMPK is necessary for Treg functional adaptation to microenvironmental stress during malignancy and viral pneumonia

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Abstract

CD4+FOXP3+ regulatory T (Treg) cells maintain self-tolerance, suppress the immune response to cancer, and protect against tissue injury during acute inflammation. Treg cells require mitochondrial metabolism to function, but how Treg cells adapt their metabolic programs to optimize their function during an immune response occurring in a metabolically stressed microenvironment remains unclear. Here, we tested whether Treg cells require the energy homeostasis-maintaining enzyme AMPK to adapt to metabolically aberrant microenvironments caused by malignancy or lung injury, finding that AMPK is dispensable for Treg cell immune-homeostatic function but is necessary for full Treg cell function in B16 melanoma tumors and during influenza virus pneumonia. AMPK-deficient Treg cells had lower mitochondrial mass and exhibited an impaired ability to maximize aerobic respiration. Mechanistically, we found that AMPK regulates DNA methyltransferase 1 to promote transcriptional programs associated with mitochondrial function in the tumor microenvironment. During viral pneumonia, we found that AMPK sustains metabolic homeostasis and mitochondrial activity. Induction of DNA hypomethylation was sufficient to rescue mitochondrial mass in AMPK-deficient Treg cells, linking AMPK function to mitochondrial metabolism via DNA methylation. These results define AMPK as a determinant of Treg cell adaptation to metabolic stress and offer potential therapeutic targets in cancer and tissue injury.

Authors

Manuel A. Torres Acosta, Jonathan K. Gurkan, Qianli Liu, Nurbek Mambetsariev, Carla Reyes Flores, Kathryn A. Helmin, Anthony M. Joudi, Luisa Morales-Nebreda, Kathleen Cheng, Hiam Abdala-Valencia, Samuel E. Weinberg, Benjamin D. Singer

Gene-environment interaction modifies the association between hyperinsulinemia and serum urate levels through SLC22A12

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Abstract

BACKGROUND. Hyperinsulinemia and insulin resistance often accompany elevated serum urate levels (hyperuricemia), a highly heritable condition that triggers gout; however, the underlying mechanisms are unclear. METHODS. We evaluated the association between the index of hyperinsulinemia and the fractional excretion of urate (FEUA) in 162 outpatients. The underlying mechanisms were investigated through single-cell data analysis and kinase screening combined with cell culture experiments. In 377,358 participants of the UK Biobank (UKBB), we analyzed serum urate, hyperinsulinemia, and salt intake. We also examined gene-environment interactions using single nucleotide variants in SLC22A12, which encodes urate transporter 1 (URAT1). RESULTS. The index of hyperinsulinemia was inversely associated with FEUA independently of other covariates. Mechanistically, URAT1 cell-surface abundance and urate transport activity were regulated by URAT1-Thr408 phosphorylation, which was stimulated by hyperinsulinemia via AKT. Kinase screening and single-cell data analysis revealed that SGK1, induced by high salt, activated the same pathway, increasing URAT1. Arg405 was essential for these kinases to phosphorylate URAT1-Thr408. In UKBB participants, hyperinsulinemia and high salt intake were independently associated with increased serum urate levels. We found that SLC22A12 eQTL rs475688 synergistically enhanced the positive association between serum urate and hyperinsulinemia. CONCLUSION. URAT1 mediates the association between hyperinsulinemia and hyperuricemia. Our data provide evidence for the role of gene-environment interactions in determining serum urate levels, paving the way for personalized management of hyperuricemia. FUNDING. ACRO Research Grants of Teikyo University; JSPS; the Japanese Society of Gout and Uric & Nucleic Acids; Fuji Yakuhin; Nanken-Kyoten; Medical Research Center Initiative for High Depth Omics.

Authors

Wataru Fujii, Osamu Yamazaki, Daigoro Hirohama, Ken Kaseda, Emiko Kuribayashi-Okuma, Motonori Tsuji, Makoto Hosoyamada, Yuta Kochi, Shigeru Shibata

Proteostasis and metabolic dysfunction characterize a subset of storage-induced senescent erythrocytes targeted for post-transfusion clearance

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Abstract

Although refrigerated storage slows the metabolism of volunteer donor RBCs, which is essential in transfusion medicine, cellular aging still occurs throughout this in vitro process. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSEhigh) and morphologically-normal RBCs (CFSElow), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSEhigh RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSEhigh RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSEhigh RBC membranes. CFSEhigh RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen perfusion ex vivo. Conversely, molecular, cellular, and circulatory properties of long-stored CFSElow RBCs resembled those of short-stored RBCs. CFSEhigh RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in these storage-induced senescent RBCs targeted for clearance.

Authors

Sandy Peltier, Mickaël Marin, Monika Dzieciatkowska, Michaël Dussiot, Micaela Kalani Roy, Johanna Bruce, Louise Leblanc, Youcef Hadjou, Sonia Georgeault, Aurélie Fricot, Camille Roussel, Daniel Stephenson, Madeleine Casimir, Abdoulaye Sissoko, François Paye, Safi Dokmak, Papa Alioune Ndour, Philippe Roingeard, Emilie-Fleur Gautier, Steven L. Spitalnik, Olivier Hermine, Pierre A. Buffet, Angelo D’Alessandro, Pascal Amireault

TET2 suppresses vascular calcification by forming inhibitory complex with HDAC1/2 and SNIP1 independent of demethylation

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Abstract

Osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) has been recognized as the principal mechanism underlying vascular calcification (VC). Runt-related transcription factor 2 (RUNX2) in VSMCs plays a pivotal role because it constitutes an essential osteogenic transcription factor for bone formation. As a key DNA demethylation enzyme, ten-eleven translocation 2 (TET2) is crucial in maintaining the VSMC phenotype. However, whether TET2 involves in VC progression remains elusive. Here we identified a substantial downregulation of TET2 in calcified human and mouse arteries, as well as human primary VSMCs. In vitro gain- and loss-of function experiments demonstrated TET2 regulated VC. Subsequently, in vivo knockdown of TET2 significantly exacerbated VC in both vitamin D3 and adenine-diet-induced chronic kidney disease (CKD) mice models. Mechanistically, TET2 binds to and suppresses the activity of the P2 promoter within the RUNX2 gene, whereas an enzymatic loss-of-function mutation of TET2 has a comparable effect. Furthermore, TET2 forms a complex with histone deacetylases 1/2 (HDAC1/2 ) to deacetylate H3K27ac on the P2 promoter, thereby inhibiting its transcription. Moreover, SNIP1 is indispensable for TET2 to interact with HDAC1/2 to exert inhibitory effect on VC, and knockdown of SNIP1 accelerated VC in mice. Collectively, our findings imply that TET2 might serve as a potential therapeutic target for VC.

Authors

Dayu He, Jianshuai Ma, Ziting Zhou, Yanli Qi, Yaxin Lian, Feng Wang, Huiyong Yin, Huanji Zhang, Tingting Zhang, Hui Huang

Tumor-specific surface marker-independent targeting of tumors through nanotechnology and bioorthogonal glycochemistry

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Abstract

Biological targeting is crucial for effective cancer treatment with reduced toxicity but is limited by the availability of tumor surface markers. To overcome this, we developed a nanoparticle-based, Tumor-specific suRfACE maRker-independent (TRACER) targeting approach. Utilizing the unique biodistribution properties of nanoparticles, we encapsulated Ac4ManNAz to selectively label tumors with azide reactive groups. Surprisingly, while NP-delivered Ac4ManNAz was cleared by the liver, it did not label macrophages, potentially reducing off-target effects. To exploit this tumor-specific labeling, we functionalized anti-4-1BB antibodies with dibenzocyclooctyne (DBCO) to target azide-labeled tumor cells and activate the immune response. In syngeneic B16F10 melanoma and orthotopic 4T1 breast cancer models, TRACER enhanced anti-4-1BB’s therapeutic efficacy, increasing median survival time. Immunofluorescence analyses revealed increased tumor infiltration of CD8+ T and NK cells with TRACER. Importantly, TRACER reduced hepatotoxicity associated with anti-4-1BB, resulting in normal serum ALT and AST levels and decreased CD8+ T cell infiltration in the liver. Quantitative analysis confirmed a 4.5-fold higher tumor-to-liver ratio of anti-4-1BB accumulation with TRACER compared to conventional anti-4-1BB antibodies. Our work provides a promising approach for developing targeted cancer therapies that circumvent limitations imposed by the paucity of tumor-specific markers, potentially improving efficacy and reducing off-target effects to overcome liver toxicity associated with anti-4-1BB.

Authors

Hyesun Hyun, Bo Sun, Mostafa Yazdimamaghani, Albert Wielgus, Yue Wang, Stephanie Ann Montgomery, Tian Zhang, Jianjun Cheng, Jonathan S. Serody, Andrew Z. Wang

Activin A activation of Smad3 mitigates innate inflammation in mouse models of psoriasis and sepsis

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Abstract

Phosphorylation of Smad3 is a critical mediator of TGF-β signaling, which plays an important role in regulating innate immune responses. However, whether Smad3 activation can be regulated in innate immune cells in TGF-β-independent contexts remains poorly understood. Here, we show that Smad3 is activated through the phosphorylation of its C-terminal residues (pSmad3C) in murine and human macrophages in response to bacterial and viral ligands, which is mediated by Activin A in a TGF-β independent manner. Specifically, infectious ligands, such as LPS, induced secretion of Activin A through the transcription factor STAT5 in macrophages, and Activin A signaling in turn activated pSmad3C. This Activin A-Smad3 axis controlled the mitochondrial ATP production and ATP conversion into adenosine by CD73 in macrophages, enforcing an anti-inflammatory mechanism. Consequently, mice with a deletion of Activin A receptor 1b specifically in macrophages (Acvr1bf/f-Lyz2cre) succumbed more to sepsis due to uncontrolled inflammation and exhibited exacerbated skin disease in a mouse model of imiquimod-induced psoriasis. Thus, we have revealed a previously unrecognized natural brake to inflammation in macrophages that occurs through the activation of Smad3 in an Activin A-dependent manner.

Authors

Thierry Gauthier, Yun-Ji Lim, Wenwen Jin, Na Liu, Liliana C. Patiño, Weiwei Chen, James Warren, Daniel Martin, Robert J. Morell, Gabriela S. Dveksler, Gloria H. Su, WanJun Chen

Transcriptomic profiling after B-cell depletion reveals central and peripheral immune cell changes in multiple sclerosis

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Abstract

Multiple sclerosis (MS) is a complex genetically mediated autoimmune disease of the central nervous system where anti-CD20-mediated B cell depletion is remarkably effective in the treatment of early disease. While previous studies investigated the effect of B cell depletion on select immune cell subsets using flow cytometry-based methods, the therapeutic impact on patient immune landscape is unknown. In this study, we explored how B cell depleting therapies modulate the immune landscape using single-cell RNA sequencing (scRNAseq). We demonstrate that B cell depletion leads to cell type-specific changes in the abundance and function of CSF macrophages and peripheral blood monocytes. Specifically, a CSF-specific macrophage population with an anti-inflammatory transcriptomic signature and peripheral CD16+ monocytes increased in frequency post-B cell depletion. This was accompanied by increases in TNFα messenger RNA and protein in monocytes post-B cell depletion, consistent with the finding that anti-TNFα treatment exacerbates autoimmune activity in MS. In parallel, B cell depletion induced changes in peripheral CD4+ T cell populations, including increases in the frequency of TIGIT+ regulatory T cells and marked decreases in the frequency of myelin peptide loaded-tetramer binding CD4+ T cells. Collectively, this study provides an exhaustive transcriptomic map of immunological changes, revealing different cell-type specific reprogramming as a result of B cell depletion treatment in MS.

Authors

Jessica Wei, Jeonghyeon Moon, Yoshiaki Yasumizu, Le Zhang, Khadir Raddassi, Nicholas C. Buitrago-Pocasangre, M. Elizabeth Deerhake, Nicolas Strauli, Chun-Wei Chen, Ann Herman, Rosetta Pedotti, Catarina Raposo, Isaiah Yim, Jenna L. Pappalardo, Erin E. Longbrake, Tomokazu S. Sumida, Pierre-Paul Axisa, David A. Hafler

Glucagon-like peptide-1 receptor agonists but not dipeptidyl peptidase-4 inhibitors reduce alcohol intake

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Abstract

Background: Despite growing preclinical evidence that glucagon-like peptide-1 receptor agonists (GLP-1RAs) could be repurposed to treat alcohol use disorder (AUD), clinical evidence is scarce. Additionally, the potential impact of dipeptidyl peptidase-4 inhibitors (DPP-4Is) on alcohol intake is largely unknown. Methods: We conducted a large cohort study using 2008-2023 electronic health records data from the U.S. Department of Veterans Affairs. Changes in Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) scores were compared between propensity-score-matched GLP-1RA recipients, DPP-4I recipients, and unexposed comparators. We further tested the effects of two DPP-4Is, linagliptin and omarigliptin, on binge-like alcohol drinking in mice and operant oral alcohol self-administration in alcohol-dependent rats, models previously used to show a significant effect of the GLP-1RA semaglutide in reducing alcohol intake. Results: GLP-1RA recipients reported a greater reduction in AUDIT-C scores than unexposed individuals [difference-in-difference: 0.09(0.03,0.14), p=0.0025] and DPP-4I recipients [difference-in-difference: 0.11(0.05,0.17), p=0.0002]. Reductions in drinking were more pronounced among individuals with baseline AUD [GLP-1RA vs. unexposed: 0.51(0.29,0.72), p<0.0001; GLP-1RA vs. DPP-4I: 0.65(0.43,0.88), p<0.0001] and baseline hazardous drinking [GLP-1RA vs. unexposed: 1.38(1.07,1.69), p<0.0001; GLP-1RA vs. DPP-4I: 1.00(0.68,1.33), p<0.0001]. There were no differences between DPP-4I recipients and unexposed individuals. The latter results were confirmed via a reverse translational approach. Specifically, neither linagliptin nor omarigliptin reduced alcohol drinking in mice or rats. The rodent experiments also confirmed target engagement as both DPP-4Is reduced blood glucose levels. Conclusion: Convergent findings across humans, mice, and rats indicate that GLP-1RAs but not DPP-4Is reduce alcohol consumption and may be efficacious in treating AUD.

Authors

Mehdi Farokhnia, John Tazare, Claire L. Pince, Nicolaus Bruns Vi, Joshua C. Gray, Vincent Lo Re III, David A. Fiellin, Henry R. Kranzler, George F. Koob, Amy C. Justice, Leandro F. Vendruscolo, Christopher T. Rentsch, Lorenzo Leggio

IL33 protects from recurrent C. difficile infection by restoration of humoral immunity

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Abstract

Clostridioides difficile infection (CDI) recurs in one of five patients. Monoclonal antibodies targeting the virulence factor TcdB reduce disease recurrence, suggesting that an inadequate anti-TcdB response to CDI leads to recurrence. In patients with CDI, we discovered that IL33 measured at diagnosis predicts future recurrence, leading us to test the role of IL33 signaling in the induction of humoral immunity during CDI. Using a mouse recurrence model, IL33 was demonstrated to be integral for anti-TcdB antibody production. IL33 acted via ST2+ ILC2 cells, facilitating germinal center T follicular helper (GC-Tfh) cell generation of antibodies. IL33 protection from reinfection was antibody-dependent, as mMT KO mice and mice treated with anti-CD20 mAb were not protected. These findings demonstrate the critical role of IL33 in generating humoral immunity to prevent recurrent CDI.

Authors

Farha Naz, Md Jashim Uddin, Nicholas M. Hagspiel, Mary K. Young, David Tyus, Rachel Boone, Audrey C. Brown, Girija Ramakrishnan, Isaura Rigo, Claire Fleming, Gregory R. Madden, William A. Petri Jr.

Acute kidney injury triggers hypoxemia by lung intravascular neutrophil retention that reduces capillary blood flow

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Abstract

Sterile acute kidney injury (AKI) is common in the clinic and frequently associated with unexplained hypoxemia that does not improve with dialysis. AKI induces remote lung inflammation with neutrophil recruitment in mice and humans, but which cellular cues establish neutrophilic inflammation and how it contributes to hypoxemia is not known. Here we report that AKI induces rapid intravascular neutrophil retention in lung alveolar capillaries without extravasation into tissue or alveoli, causing hypoxemia by reducing lung capillary blood flow in the absence of substantial lung interstitial or alveolar edema. In contrast to direct ischemic lung injury, lung neutrophil recruitment during remote lung inflammation did not require cues from intravascular non-classical monocytes or tissue-resident alveolar macrophages. Instead, lung neutrophil retention depended on neutrophil chemoattractant CXCL2 released by activated classical monocytes. Comparative single-cell RNA-sequencing analysis of direct and remote lung inflammation revealed that alveolar macrophages are highly activated and produce CXCL2 only in direct lung inflammation. Establishing a CXCL2 gradient into the alveolus by intratracheal CXCL2 administration during AKI-induced remote lung inflammation enabled neutrophils to extravasate. We thus discovered important differences in lung neutrophil recruitment in direct versus remote lung inflammation and identified lung capillary neutrophil retention that negatively affects oxygenation by causing a ventilation-perfusion mismatch as a driver of AKI-induced hypoxemia.

Authors

Yohei Komaru, Liang Ning, Carine Lama, Anusha Suresh, Eirini Kefaloyianni, Mark J. Miller, Shinichi Kawana, Hailey M. Shepherd, Wenjun Li, Daniel Kreisel, Andreas Herrlich

Macrophage-mediated interleukin-6 signaling drives ryanodine receptor-2 calcium leak in postoperative atrial fibrillation

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Abstract

Postoperative atrial fibrillation (poAF) is AF occurring days after surgery with a prevalence of 33% among patients undergoing open-heart surgery. The degree of postoperative inflammation correlates with poAF risk, but less is known about the cellular and molecular mechanisms driving postoperative atrial arrhythmogenesis. We performed single-cell RNA sequencing comparing atrial non-myocytes from mice with versus without poAF, which revealed infiltrating CCR2+ macrophages to be the most altered cell type. Pseudotime trajectory analyses identified Il-6 as a top gene in macrophages, which we confirmed in pericardial fluid collected from human patients after cardiac surgery. Indeed, macrophage depletion and macrophage-specific Il6ra conditional knockout (cKO) prevented poAF in mice. Downstream STAT3 inhibition with TTI-101 and cardiomyocyte-specific Stat3 cKO rescued poAF, indicating a pro-arrhythmogenic role of STAT3 in poAF development. Confocal imaging in isolated atrial cardiomyocytes (ACMs) uncovered a novel link between STAT3 and CaMKII-mediated ryanodine receptor-2 (RyR2)-Ser(S)2814 phosphorylation. Indeed, non-phosphorylatable RyR2S2814A mice were protected from poAF, and CaMKII inhibition prevented arrhythmogenic Ca2+ mishandling in ACMs from mice with poAF. Altogether, we provide multiomic, biochemical, and functional evidence from mice and humans that IL-6-STAT3-CaMKII signaling driven by infiltrating atrial macrophages is a pivotal driver of poAF that portends therapeutic utility for poAF prevention.

Authors

Joshua A. Keefe, Yuriana Aguilar-Sanchez, Jose Alberto Navarro-Garcia, Isabelle Ong, Luge Li, Amelie Paasche, Issam Abu-Taha, Marcel A. Tekook, Florian Bruns, Shuai Zhao, Markus Kamler, Ying H. Shen, Mihail G. Chelu, Li Na, Dobromir Dobrev, Xander H. T. Wehrens

Divergent populations of HIV-infected naïve and memory CD4+ T-cell clones in children on antiretroviral therapy

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Abstract

BACKGROUND. Naïve cells comprise 90% of the CD4+ T-cell population in neonates and exhibit distinct age-specific capacities for proliferation and activation. We hypothesized that HIV-infected naïve CD4+ T-cell populations in children on long-term antiretroviral therapy (ART) would thus be distinct from infected memory cells. METHODS. Peripheral blood naïve and memory CD4+ T cells from 8 children with perinatal HIV on ART initiated at age 1.7-17 months were isolated by FACS. DNA was extracted from sorted cells and HIV proviruses counted, evaluated for intactness, and subjected to integration site analysis. RESULTS. Naïve CD4+ T cells containing HIV proviruses were detected in children with 95% statistical confidence. A median of 4.7% of LTR-containing naïve CD4+ T cells also contained HIV genetic elements consistent with intactness. Full-length proviral sequencing confirmed intactness of one provirus. In the participant with the greatest level of naïve cell infection, ISA revealed infected expanded cell clones in both naïve and memory T cells with no common HIV integration sites detected between subsets. Divergent integration site profiles reflected differential gene expression patterns of naïve and memory T cells. CONCLUSIONS. These results demonstrate that HIV persists in both naïve and memory CD4+ T cells that undergo clonal expansion and harbor intact proviruses, suggesting that infected memory T-cell clones do not frequently arise from naïve cell differentiation in children with perinatal HIV on long-term ART. FUNDING. Center for Cancer Research, NCI and Office of AIDS Research funding to MFK, NCI FLEX funding to JWR. Children’s and Emory JFF pilot to MM.

Authors

Mary Grace Katusiime, Victoria Neer, Shuang Guo, Sean C. Patro, Wenjie Wang, Brian Luke, Adam A. Capoferri, Xiaolin Wu, Anna M. Horner, Jason W. Rausch, Ann Chahroudi, Maud Mavigner, Mary F. Kearney

Restoring mitochondrial function promotes hematopoietic reconstitution from cord blood following cryopreservation-related functional decline

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Abstract

Umbilical cord blood (UCB) showcases substantial roles in hematopoietic stem cells (HSCs) transplantation and regenerative medicine. UCB is usually cryopreserved for years before use. Whether and how cryopreservation affects its function remain unclear. We constructed single-cell transcriptomic profile of CD34+ hematopoietic stem and progenitor cells (HSPCs) and mononuclear cells (MNCs) from fresh and cryopreserved UCB stored for 1-, 5-, 10-, and 19- years. Compared to fresh UCB, cryopreserved HSCs and multipotent progenitors (MPPs) exhibited more active cell cycle and lower HSC/MPP signature gene expressions. Hematopoietic reconstitution of cryopreserved HSPCs gradually decreased during the first 5 years but stabilized thereafter, aligning with the negative correlation between clinical neutrophil engraftment and cryopreservation duration of UCB. Cryopreserved HSPCs also showed reduced megakaryocyte generation. In contrast, cryopreserved natural killer (NK) cells and T cells maintained cytokine production and cytotoxic ability comparable to fresh cells. Mechanistically, cryopreserved HSPCs exhibited elevated reactive oxygen species, reduced ATP synthesis, and abnormal mitochondrial distribution, which collectively led to attenuated hematopoietic reconstitution. These effects could be ameliorated by sulforaphane. Together, we elucidated the negative impact of cryopreservation on UCB HSPCs and provided sulforaphane as a mitigation strategy, broadening the temporal window and scope for clinical applications of cryopreserved UCB.

Authors

Yaojin Huang, Xiaowei Xie, Mengyao Liu, Yawen Zhang, Junye Yang, Wenling Yang, Yu Hu, Saibing Qi, Yahui Feng, Guojun Liu, Shihong Lu, Xuemei Peng, Jinhui Ye, Shihui Ma, Jiali Sun, Lu Wang, Linping Hu, Lin Wang, Xiaofan Zhu, Hui Cheng, Zimin Sun, Junren Chen, Fang Dong, Yingchi Zhang, Tao Cheng