Inflammation
Abstract
The inflammatory response resulting from the abnormal accumulation of metabolites has been implicated in the pathogenesis of organ fibrosis; however, its role and underlying mechanisms in renal fibrosis remain unclear. In this study, we observed a negative correlation between fumarate hydratase (FH) expression and the degree of renal fibrosis. Loss of FH function was associated with heightened inflammation and exacerbated tubulointerstitial damage in the kidney. Moreover, FH deficiency aggravated fibrosis in both the liver and lungs. Mechanistically, the depletion of FH in renal tubular cells led to fumarate accumulation. Fumarate directly succinated A-kinase anchoring protein 12 at cysteine 670, thereby diminishing its capacity to inhibit the activity of protein kinase Cζ (PKCζ). This process exacerbated renal inflammation and fibrosis by activating the downstream PKCζ/NF-κB and PKCζ/β-catenin pathways. Additionally, the upregulation of FH through adeno-associated virus 2/9-mediated FH overexpression markedly mitigated renal inflammation and fibrosis. These findings highlighted the important role of fumarate accumulation in the advancement of renal fibrosis, supporting FH as a potential therapeutic target in renal fibrosis.
Authors
Shuai Sun, Xu-yang Yan, Yu-hang Dong, Jian-min You, Zhen-yu Guo, Dong-xue Lv, Shuai-shuai Xie, Rui Hou, Xiang-yu Li, Ju-tao Yu, Xiao-yu Shen, Jie Wei, Zhen-yu Song, Zi-qi Chen, Yun-long Zhu, Xing-xin Xu, Juan Jin, Jia-gen Wen, Hao Wang, Xiao-ming Meng, Wei Wang
Abstract
Obesity is increasingly implicated in hematopoietic malignancies, yet its role in mutation-driven myeloid leukemias remains unclear. Using UK Biobank data from over 440,000 individuals, we found obesity traits including elevated BMI and waist-to-hip ratio were associated with type 2 diabetes, increased plasma IL-17A (interleukin-17A), reduced GLP-1R (glucagon like peptide 1 receptor) expression, and heightened risk of myeloid malignancies. Transplantation of protein tyrosine phosphatase non-receptor type 11, PTPN11 (Shp2E76K/+) mutant hematopoietic stem/progenitors into obese mice demonstrated that metabolic inflammation accelerates leukemogenesis via myeloid cell expansion, lipid metabolic rewiring, IL-17A activation, and accumulation of M2-like tumor-associated macrophages (TAMs), accompanied by T-cell exhaustion and impaired antigen presentation. Notably, dual therapy with an anti-IL-17A antibody and a GLP-1R agonist reversed these effects, by reducing M2-like TAMs, restoring Ciita-dependent antigen presentation, Tyk2-mediated IFNγ signaling, reactivated T-cell responses, and reducing leukemic burden. These findings establish IL-17A driven, metabolism-coupled immunosuppression as a mechanistic link between obesity and SHP2-mutant myeloid leukemias, highlighting a tractable therapeutic strategy for high-risk obese patients.
Authors
Reuben Kapur, Linke Li, Rahul Kanumuri, Kanaka Sai Ram Padam, Baskar Ramdas, Chiranjeevi Pasala, Gabriela Chiosis, Lakshmi Reddy Palam, Ramesh Kumar, Satoshi Koyama, Pradeep Natarajan, Laura S. Haneline, Zhi Yu, Santhosh Kumar Pasupuleti
Abstract
Obesity is associated with impaired wound healing, but the mechanisms linking excess adiposity to aberrant tissue repair remain unresolved. Heterotopic ossification (HO) is a severe example of pathologic tissue repair in which mesenchymal progenitor cells (MPCs) undergo aberrant osteochondral differentiation within soft tissue, leading to joint contractures and pain. Here, we show that accumulation of dietary omega-6 (ω-6) lipids in the injury site is a key mechanism linking obesity to HO. Specifically, in mice fed a high-fat diet (HFD), injured tissues were enriched in linoleic and arachidonic acids, providing substrate for myeloid cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production. PGE2 then drove a transcriptional program in mesenchymal progenitor cells that promoted osteochondral differentiation. An isocaloric, low linoleic acid HFD reduced HO despite comparable obesity, demonstrating that dietary lipid composition, rather than adiposity alone, drove pathological repair. Clinical data mirrored these findings, showing that obesity conferred increased HO risk, and COX-2 inhibition reduced HO exclusively in obese patients. Together, these findings identify injury site ω-6 lipid enrichment as the key signal linking the diet to MPC reprogramming, pointing to dietary lipid modulation as an actionable strategy to limit HO in obesity.
Authors
Stefanie L. Moye, Monisha Mittal, Tarun Srinivasan, Sneha Korlakunta, Chase A. Pagani, Ayelet Dar, Oromo Geshow, Dylan Feist, Lauren G. Zacharias, Zhao Li, Aaron W. James, Gerta Hoxhaj, Andrew M. Smith, Katherine A. Gallagher, Thomas P. Mathews, Robert J. Tower, Benjamin Levi
Abstract
Imaging-based single-cell spatial transcriptomics (iSCST) on formalin-fixed, paraffin-embedded (FFPE) tissue enables comprehensive analysis of archived specimens while preserving spatial context, critical to an understanding of ulcerative colitis (UC) pathology. Here, we deployed a robust framework for applying iSCST to clinical FFPE mucosal biopsies from patients with UC, immune checkpoint inhibitor-induced (ICI) colitis and healthy controls. iSCST using custom Xenium gene panels enabled precise detection of diverse cell subsets and disease-specific genes. We mapped transcriptionally distinct fibroblast subsets within mucosal niches, including inflammation-associated fibroblasts (IAFs), and identified colitis-specific neighborhoods formed by IAFs, monocytes, and neutrophils. Transcriptional signatures and spatial neighborhoods uncovered through iSCST were associated with vedolizumab (VDZ) response, with non-responders exhibiting either an innate IAF-monocyte-neutrophil signature or adaptive gut-associated lymphoid tissue (GALT) signature, while responders showed enrichment of an epithelial cellular neighborhood. These signatures were validated in an internal and an external dataset, supporting the existence of two distinct archetypes of treatment resistance to VDZ in UC. This iSCST framework provides a powerful approach for analyzing FFPE tissues, offering insights into colitis-associated cellular networks and identifying biomarkers to enhance patient risk stratification in routine clinical workflows.
Authors
Elvira Mennillo, Madison L. Lotstein, Gyehyun Lee, Julian H. Hou, Vrinda Johri, Donna E. Leet, Christina A. Ekstrand, Jessica Tsui, Jun Yan He, Uma Mahadevan, Walter L. Eckalbar, Ryan M. Gill, Christopher J. Bowman, David Y. Oh, Gabriela K. Fragiadakis, Michael G. Kattah, Alexis J. Combes
Abstract
BACKGROUND. Sepsis is a leading cause of morbidity and mortality in critically ill children, yet heterogeneous immune responses complicate the development of targeted therapies and the host immune factors driving sepsis pathobiology remain unclear. METHODS. We integrated deep immune phenotyping, plasma proteomics, single-cell transcriptomics, and phosphoflow cytometry in a prospective cohort of 88 critically ill children to elucidate the mechanisms underlying immune heterogeneity. RESULTS. Unsupervised clustering of plasma cytokines identified three immunologic subgroups, including a high-severity group (“Group C”) characterized by hypercytokinemia driven by IL-6 and IFN-γ. Group C exhibited distinct alterations in immune cell frequency and activation, with a strong association between hyperinflammatory cytokine signaling and lymphocyte dysfunction. Single-cell RNA sequencing revealed transcriptional signatures of T cell activation and metabolic stress, with suppression of a lymphoid protective gene program across CD8⁺ T cell subsets. Despite increased expression of activation markers, T cell receptor repertoire analysis revealed no dominant clonotypes, consistent with bystander activation. Phosphoflow cytometry demonstrated baseline STAT1/STAT3 hyperactivation in Group C CD8⁺ T cells, which failed to respond to αCD3/αCD28/αCD49d stimulation. CONCLUSIONS. These findings define an IL‑6/IFN‑γ–driven endotype of T cell dysfunction in pediatric sepsis and highlight the JAK/STAT axis as a rational target for immunomodulatory therapy. FUNDING. K12HD047349, K23GM159013, K08AI135091, R01HD095976, Thrasher Research Foundation, Burroughs Wellcome Fund CAMS, Immune Deficiency Foundation, Primary Immune Deficiency Treatment Consortium, Barbara Brodsky Foundation, CHOP Research Institute
Authors
Robert B. Lindell, Samir U. Sayed, Jose S. Campos Duran, Sydney A. Sheetz, Apoorva Babu, Montana S. Knight, Andrea A. Mauracher, Ceire A. Hay, Peyton E. Conrey, Julie C. Fitzgerald, Nadir Yehya, Stephen T. Famularo III, Teresa Arroyo, Richard Tustin III, Hossein Fazelinia, Edward M. Behrens, David T. Teachey, Lisa R. Forbes Satter, Alexandra F. Freeman, Jenna R.E. Bergerson, Steven M. Holland, Jennifer W. Leiding, Scott L. Weiss, Mark W. Hall, Deanne M. Taylor, Rui Feng, E. John Wherry, Nuala J. Meyer, Sarah E. Henrickson
Abstract
BACKGROUND. Right ventricular failure (RVF) is a major determinant of mortality in pulmonary arterial hypertension (PAH), and hepatic dysfunction predicts adverse outcomes. However, the cell-specific effects of PAH/RVF on the human liver remain poorly defined. METHODS. We performed single-nucleus RNA sequencing of autopsy-derived liver tissue from 5 PAH patients and 4 non-PAH controls and compared these findings with publicly available single-nucleus RNA sequencing datasets from non-alcoholic steatohepatitis (NASH) and Fontan-associated liver disease (FALD). Transcriptomic analyses were integrated with histologic assessment, mitochondrial-enriched proteomics, and correlated with clinical markers of PAH/RVF severity. RESULTS. PAH livers showed cell-specific metabolic, inflammatory, and fibrotic remodeling distinct from NASH and FALD. PAH hepatocytes exhibited a hypoxia-adapted, Warburg-like metabolic phenotype with reduced fatty acid metabolism, gluconeogenesis, cytochrome P450 activity, and ketone metabolism. PAH endothelial cells demonstrated increased glycolytic pathway activity and disrupted adhesion/barrier signaling. PAH hepatic stellate cells displayed HIF-1 and PI3K-Akt pathway activation, and increased IL6 expression, which resulted in central vein fibrotic remodeling. PAH macrophages showed complement activation with reduced JAK-STAT signaling. Finally, HSC HIF-1 activity correlated with clinical markers of PAH/RVF severity. CONCLUSION. PAH induces a distinct metabolic and inflammatory hepatopathy characterized by hepatocyte metabolic reprogramming, HSC activation, and macrophage complement signaling. These findings support PAH-associated hepatopathy as a disease-specific end-organ phenotype linked to RVF severity.
Authors
Madelyn J. Blake, Sally E. Prins, Jeffrey C. Blake, Lynn M. Hartweck, Jenna B. Mendelson, Steeve Provencher, Sandra Breuils-Bonnet, Sebastien Bonnet, Kurt W. Prins
Abstract
Dysfunctional intestinal fibrosis is an irreversible complication of Crohn’s disease (CD), The complex heterogeneity of intestinal mesenchymal cells makes it difficult to understand the pathogenesis of intestinal fibrosis. Previously, we identified Meflin as a marker of fibroblast subsets. This study aimed to explore the role of Meflin-positive fibroblasts in intestinal fibrogenesis and investigate the potential of pharmacological control of Meflin expression as a treatment for patients with CD. Our results indicated that Meflin expression was upregulated in fibroblasts at the early stage of fibrosis but was downregulated in established fibrosis in both patients with CD and two different mouse models, which are the chronic dextran sodium sulfate (DSS) model and an interleukin-10-deficient model that spontaneously develops intestinal inflammation. Meflin-deficient mice exacerbated intestinal fibrosis with dysregulated expression of non-canonical Wnt ligand WNT5A and its receptor ROR2. Pharmacologically induced Meflin expression through the administration of a synthetic retinoid reversed intestinal fibrosis in the DSS model and suppressed pro-fibrotic protein secretion in fibroblasts isolated from patients with CD. Our findings indicate that Meflin-positive fibroblasts represent a functional subpopulation that suppresses intestinal fibrosis. Augmentation of Meflin expression shows antifibrotic effects and holds promise as a therapeutic approach for intestinal fibrosis in patients with CD.
Authors
Jingxi Mu, Keiko Maeda, Tadashi Iida, Shinji Mii, Nobutoshi Esaki, Yukihiro Shiraki, Yasuyuki Mizutani, Masanao Nakamura, Takeshi Yamamura, Tsunaki Sawada, Eri Ishikawa, Kentaro Murate, Takashi Hirose, Kazuhiro Furukawa, Akina Oishi, Haruhiko Suzuki, Takayoshi Kishida, Goro Nakayama, Mitsuhiro Fujishiro, Hiroki Kawashima, Atsushi Enomoto
Abstract
Sepsis is a systemic response to infection with life-threatening consequences such as hemolysis, a predictor of mortality risks for the disease. Here, by measuring organism-wide changes in gene expression, we discovered that the secreted phospholipase PLA2G5 is induced in colon cell types during sepsis. The genetic deletion of Pla2g5 and treatment with a PLA2G5 antibody were both associated with protection from lethal sepsis. Treatment with a PLA2G5 antibody during sepsis was associated with increased splenic red pulp macrophages and improved iron homeostasis, linking PLA2G5 to red blood cell homeostasis during sepsis. Mechanistically, bloodborne PLA2G5 led to intravascular hemolysis through its lipolytic activity on red blood cell membranes. In humans with sepsis due to bacterial, fungal, or viral infections, the serum level of PLA2G5 was elevated and predictive of disease severity and mortality. We conclude that sepsis corrupts PLA2G5 into becoming an intravascular hemolytic factor which is toxic for host red blood cells.
Authors
Michihiro Takahama, Krysta S. Wolfe, Gabriella Richey, Madison Plaster, Anna Czapar, Fabian Hernandez, Denis Cipurko, Tatsuki Ueda, Yoshimi Miki, Yuki Nagasaki, Yoshitaka Taketomi, Tatsuya Saitoh, Tadafumi Kawamoto, Steven M. Dudek, Makoto Murakami, Nicolas Chevrier
Abstract
BACKGROUND. Elevated lipoprotein(a) [Lp(a)] is associated with a higher risk of atherosclerotic cardiovascular disease (ASCVD). Although Lp(a) is a genetically determined risk factor, the plasma proteomic features associated with Lp(a) and whether they provide information about ASCVD risk beyond Lp(a) concentration are not well characterized. OBJECTIVE. We sought to identify plasma proteomic features associated with Lp(a) concentration and to evaluate whether an Lp(a)-associated proteomic signature is associated with ASCVD phenotypes in young, healthy adults. METHODS. In the Coronary Artery Risk Development in Young Adults (CARDIA) study, we measured Year 7 Lp(a) and 184 cardiovascular proteins using the Olink proximity extension assay in 3,920 participants without prior coronary heart disease. Lp(a)-associated proteomic signatures were derived using LASSO regression in a split-sample design and tested for association with coronary artery calcification (CAC), incident CHD, and hs-CRP over 27 years of follow-up. External replication was performed in the UK Biobank (n=37,996). RESULTS. Lp(a) was associated with CAC (OR 1.23 [1.13-1.34]; p<0.0001) and incident CHD (HR 1.23 [1.07-1.41]; p=0.004). Lp(a) correlated with proteomic features reflecting immune activation, coagulation, and vascular dysfunction. A quantitative Lp(a) proteomic score was independently associated with incident CAC (standardized beta = 0.40, p<0.0001) and hs-CRP (standardized beta = 0.11, p = 0.00015) after adjustment for Lp(a) concentration. In the UK Biobank, a recalibrated Lp(a)-associated proteomic score was associated with CRP, incident CHD, and all-cause mortality. CONCLUSIONS. In young adults, Lp(a) is associated with distinct proteomic features that independently predict ASCVD phenotypes beyond Lp(a) concentration, generating hypotheses regarding biological pathways linked to Lp(a)-related cardiovascular risk.
Authors
Sascha N. Goonewardena, Shanshan Yao, Tomasz Jurga, Lanyue Zhang, Donald Lloyd-Jones, Dilna Damodaran, Bharat Thyagarajan, David R. Jacobs Jr, Supriya Shore, Eric J. Brandt, Clary Clish, Kahraman Tanriverdi, Jane E. Freedman, Chirag J. Patel, Mark A. Sarzynski, Brian T. Emmer, John T. Wilkins, Ron Do, Vera Bittner, Ravi Shah, Marios K. Georgakis, Robert S. Rosenson, Venkatesh Murthy
Abstract
CD48 is a surface molecule with immunoregulatory functions. Following our initial report of a patient with a de novo heterozygous variant at amino acid S220 in the CD48 gene, we describe a second, unrelated patient with similar features of immune dysregulation and a missense change affecting the same residue. To further elucidate the specific pathogenic mechanisms of the identified variants, we reviewed patient records, analyzed patient-derived cells, and employed complementary in vitro and in vivo model systems, including transfected cell lines and CD48-deficient mice. We demonstrate that the variants are associated with altered distribution of CD48, characterized by diminished CD48 surface expression, intracellular retention, and activation of endoplasmic reticulum stress signaling. Patient T cells display increased susceptibility to apoptosis, reduced antiviral responses, and enhanced inflammation. Both patients exhibit T-cell lymphopenia, a restricted TCR repertoire diversity, and oligoclonal expansions consistent with antigen-driven selection. In parallel, virally-infected CD48-deficient mice recapitulate key aspects of the human phenotype, including delayed antiviral immune responses, impaired viral clearance and pronounced inflammation. We conclude that identified variants compromise CD48 cell-surface localization, impair T-cell survival and function, and predispose to inflammation, thereby highlighting the role of CD48 in immune regulation and the prevention of excessive inflammation.
Authors
Samantha Milanesi, Tiziana Lorenzini, Tommaso Marchetti, Diana Tintor, Raquel Planas, Ola Sabet, Lars Malmström, Sudip Acharya, Carson D. Williams, Zoe E. Manning, Jack H. Roser, Angelica C. Ehler, Michael Huber, Seraina Prader, Stefano Vavassori, Cullen M. Dutmer, Jordan K. Abbott, Jana Pachlopnik Schmid
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ISSN: 0021-9738 (print), 1558-8238 (online)