Inflammation
Abstract
Nonresolving inflammation and maladaptive renal repair contribute to the pathogenesis of acute kidney injury (AKI) transition to chronic kidney disease (CKD). Few therapies have been identified that can modulate these injurious pathways following AKI. Spleen tyrosine kinase (SYK) is an immune regulator expressed in the kidney and a potential therapeutic target for AKI. The effect of the selective SYK inhibitor entospletinib was studied in AKI-to-CKD transition. Entospletinib was administered to mice undergoing unilateral renal ischemia-reperfusion injury (IRI), with kidneys analyzed over 14 days. Single-cell RNA sequencing, digital spatial profiling, intravital microscopy, and flow cytometry were employed to study renal phenotypes. Entospletinib administered before and after IRI protected ischemic kidneys and significantly attenuated the transition to CKD. Entospletinib targeted leukocyte-expressed SYK and prevented neutrophil/monocyte recruitment to the kidney. Entospletinib reduced nonresolving tubulointerstitial inflammation after AKI by blocking activation of mannose receptor-1– and C-type lectin domain family 7 member A–expressing proinflammatory macrophages. The resolution of renal inflammation mediated by entospletinib was associated with a reciprocal increase in resident macrophages, reparative gene expression, preserved tubular integrity, and reduced renal fibrosis. The SYK inhibitor entospletinib resolves renal inflammation and promotes repair following AKI.
Authors
Esteban E. Elias, Arthur Lau, Sisay Getie Belay, Afshin Derakhshani, Graciela Andonegui, Craig N. Jenne, Antoine Dufour, Nathan A. Bracey, Justin Chun, Daniel A. Muruve
Abstract
Butyrate, a microbiome-derived short-chain fatty acid with pleiotropic effects on inflammation and metabolism, has been shown to significantly reduce atherosclerotic lesions, rectify routine metabolic parameters such as low-density lipoprotein cholesterol (LDL-C), and reduce systemic inflammation in murine models of atherosclerosis. However, its foul odor, rapid metabolism in the gut and thus low systemic bioavailability limit its therapeutic effectiveness. Our laboratory has engineered an ester-linked L-serine conjugate to butyrate (SerBut) to mask its taste and odor and to coopt amino acid transporters in the gut to increase its systemic bioavailability, as determined by tissue measurements of free butyrate, produced by hydrolysis of SerBut. In an apolipoprotein E–knockout (ApoE)–/– mouse model of atherosclerosis, SerBut reduced systemic LDL-C, proinflammatory cytokines, and circulating neutrophils. SerBut enhanced inhibition of plaque progression and reduced monocyte accumulation in the aorta compared with sodium butyrate. SerBut suppressed liver injury biomarkers alanine transaminase and aspartate aminotransferase and suppressed steatosis in the liver. SerBut overcomes several barriers to the translation of butyrate and shows superior promise in slowing atherosclerosis and liver injury compared with equidosed sodium butyrate.
Authors
Taryn N. Beckman, Lisa R. Volpatti, Salvador Norton de Matos, Anna J. Slezak, Joseph W. Reda, Ada Weinstock, Leah Ziolkowski, Alex Turk, Erica Budina, Shijie Cao, Gustavo Borjas, Jung Woo Kwon, Orlando deLeon, Kirsten C. Refvik, Abigail L. Lauterbach, Suzana Gomes, Eugene B. Chang, Jeffrey A. Hubbell
Abstract
Radiation-induced lymphopenia (RIL) remains a challenging side effect of radiation therapy, often associated with poor prognosis and reduced overall survival. Although CD8+ T cells are highly radiosensitive, the dynamics of quantitative and qualitative changes to the CD8 T cell pool following exposure to high doses of ionizing radiation (IR) remains understudied. Herein, we sought to determine the long-term impact of sublethal whole body irradiation (WBI) on antigen (Ag)-inexperienced CD8 T cell pool, comprised of naïve (TN) and virtual memory (TVM) CD8+ T cells. We show that although both TN and TVM cells gradually regenerate after WBI-induced loss, TN recovery only occurs through de novo thymic production. Despite the numerical restoration, the subset and phenotypic composition of post-recovery Ag-inexperienced CD8+ T cells do not qualitatively recapitulate the pre-WBI state. Specifically, the frequency of TVM cells is increased, especially during the early stages of recovery. Within the TN subset, a lasting overrepresentation of Ly6C+CD122+ cells and an altered TCR clonotype diversity are also observed. Overall, our data highlight the dynamic changes to the Ag-inexperienced CD8+ T cell pool upon recovery from RIL.
Authors
Mohammad Heidarian, Shravan K. Kannan, Whitney Swanson, Thomas S. Griffith, John T. Harty, Vladimir P. Badovinac
Abstract
Spondyloarthritis (SpA) is an inflammatory arthritis of the spine and joints associated with intestinal inflammation, in which it is hypothesized that innate immune exposure to entero-invasive species is followed by self/bacterial peptide presentation. However, the mechanisms underlying loss of tolerance to gut bacteria in genetically at-risk individuals are unclear. Curdlan (β-1,3-glucan, dectin-1 ligand)-treated ZAP-70W163C (SKG) mice develop autoimmune arthritis and ileitis associated with Gram-negative faecal dysbiosis. Using gnotobiotic mice, we show that curdlan-treated SKG mice mono-associated with Parabacteroides goldsteinii or Lactobacillus murinus developed ileitis, arthritis and enthesitis, while BALB/c mice were tolerant. Gnotobiotic SKG ileum upregulated Il23a and ER stress genes and lost goblet cells. Whereas bacterial DNA co-localised with neutrophils and inflammatory macrophages in SKG lamina propria, peri-articular bone marrow, entheses and spleen, in BALB/c bacterial DNA co-localised with resident macrophages in lamina propria and spleen. Human psoriatic-arthritis synovial tissue also contained cell-associated peri-vascular bacterial DNA. Curdlan-treated SKG spleen/bone marrow macrophages transferred severe arthritis and expanded Th17 cells in naïve SKG recipients, while BALB/c or germ free-SKG macrophages transferred mild arthritis and regulated Th17 cells. Thus, bacterial DNA and myeloid cells in the gut and their subsequent traffic regulate or enforce T cell pathogenicity in SpA.
Authors
Benjamin Cai, Rabina Giri, Amy J. Cameron, M. Arifur Rahman, Annabelle Small, Christopher Altmann, Yenkai Lim, Linda M. Rehaume, Mark Morrison, Mihir D. Wechalekar, Jakob Begun, Anne-Sophie Bergot, Ranjeny Thomas
Abstract
Reprogramming autoreactive CD4⁺ effector T (Teff) cells into immunosuppressive regulatory T (Treg) cells represents a promising strategy for treating established autoimmune diseases. However, the stability and function of such reprogrammed Tregs under inflammatory conditions remain unclear. Here, we show that epigenetic activation of core Treg identity genes in Teff cells yields lineage-stable Effector T cell Reprogrammed Tregs (ER-Tregs). A single adoptive transfer of ER-Tregs not only prevents autoimmune neuroinflammation in mice when given before disease onset but also arrests its progression when administered after onset. Compared to Foxp3 overexpressing Teff cells, induced Tregs from naïve precursors, and endogenous Tregs, ER Tregs provide superior protection against autoimmune neuroinflammation. This enhanced efficacy stems from their inherited autoantigen specificity and selectively preserved effector cell transcriptional programs, which together bolster their fitness in inflammatory environments and enhance their suppressive capacity. Our results establish epigenetic reprogramming of autoreactive Teff cells as an effective approach to generate potent, stable Tregs for the treatment of refractory autoimmune conditions.
Authors
Tyler R. Colson, James J. Cameron, Hayley I. Muendlein, Mei-An Nolan, Jamie L. Leiriao, James H. Kim, Alexander N. Poltorak, Xudong Li
Abstract
Authors
Veethika Pandey, Heike R. Doeppler, Ligia I. Bastea, Alicia K. Fleming Martinez, Barath Shreeder, Brandy H. Edenfield, Keith L. Knutson, DeLisa Fairweather, Peter Storz
Abstract
Secondary lymphedema is characterized by fibrosis and impaired lymphatic function. Although TGF-β is a key regulator of fibrosis in this disease, the cellular mechanisms regulating this process remain unknown. Epithelial–mesenchymal transition (EMT), a mechanism by which TGF-β induces fibrosis in other skin diseases, is characterized by loss of epithelial cell markers and cellular polarity, upregulation of fibrotic gene expression, and gain of migratory capacity. Using clinical lymphedema biopsy specimens and animal models, we show that keratinocytes in the basal layer of the epidermis undergo EMT in lymphedematous skin, migrate into the dermis, and contribute to dermal fibrosis. In vitro studies using cultured primary human keratinocytes treated with lymphatic fluid from the affected limbs of patients with secondary lymphedema resulted in a TGF-β–mediated increased expression of EMT markers. We show for the first time that EMT is activated by TGF-β in secondary lymphedema and that this process plays an important role in regulating skin fibrosis in this disease.
Authors
Hyeung Ju Park, Jinyeon Shin, Ananta Sarker, Mark G. Klang, Elyn Riedel, Michelle Coriddi, Joseph H. Dayan, Sarit Pal, Babak J. Mehrara, Raghu P. Kataru
Abstract
Background & Aims Liver cirrhosis is characterized by chronic inflammation and fibrosis, with Th17 cells playing a crucial role in its progression. Recent evidence suggests that dietary salt influences immune diseases by modulating Th17 differentiation. This study assessed the impact of dietary salt on Th17-driven inflammation in patients with compensated cirrhosis and explored its effects on liver injury in mouse models. Methods A non-drug, open-label, non-randomized study involved 37 patients with compensated cirrhosis, who were given personalized guidelines to reduce salt intake over three months. Changes in Th17-driven inflammation and liver function markers were assessed at baseline and after salt restriction. In parallel, the impact of a high-salt diet on hepatic CD4+ T cells was analyzed in mouse models of acute liver injury and fibrosis. Results High salt intake was associated with Th17-mediated inflammation and correlated with markers of impaired liver function in these patients. Importantly, moderating salt intake through a personalized nutritional intervention was sufficient to reduce CD4+ T cell- mediated inflammation. Furthermore, analysis of RNA-seq data revealed enrichment of salt-induced Th17 gene signatures in both liver tissue and peripheral cells from patients with liver disease. Similarly, mice fed a high salt diet showed hepatic enrichment of Th17 cells and exacerbated liver fibrosis upon injury. Mechanistic studies revealed that high sodium conditions activated NF-κB and induced IL-6 production in hepatocytes, which may promote Th17 responses. Conclusion Dietary salt exacerbates Th17-driven inflammation and contributes to cirrhosis progression. Salt reduction may represent a viable therapeutic approach to manage inflammation in compensated cirrhosis.
Authors
Amalia Tzoumpa, Beatriz Lozano-Ruiz, Yin Huang, Joanna Picó, Alba Moratalla, María Teresa Pomares, Iván Herrera, Juanjo Lozano, María Rodríguez-Soler, Cayetano Miralles, Pablo Bellot, Paula Piñero, Fabián Tarín, Pedro Zapater, Sonia Pascual, José Manuel González-Navajas
Abstract
Psoriasis is a chronic autoimmune skin disease characterized by abnormal keratinocyte proliferation and immune dysregulation. Altered lipid metabolism has been implicated in its pathogenesis, but the underlying mechanisms remain unclear. In this study, we generated an keratinocyte-specific Sprouty RTK signaling antagonist 1 (SPRY1) knockout (Spry1ΔEpi) mouse model, which exhibits psoriasis-like symptoms. Using both psoriasis patient samples and Spry1ΔEpi mice, we investigated the role of diacylglycerol acyltransferase 2 (DGAT2) in psoriasis. Our results show that DGAT2 expression is reduced, and glycerides metabolism is disrupted in psoriatic lesions in both psoriasis patients and Spry1ΔEpi mice. Lipidomic analysis reveals significant alterations in glycerides, glycerophospholipids, sphingolipids, and fatty acids in Spry1ΔEpi mice. At the cellular level, DGAT2 downregulation and lipid dysregulation enhance Toll-like receptor 3 (TLR3)-mediated inflammatory signaling in keratinocytes. Furthermore, increased DGAT2 secretion from keratinocytes promotes CD8⁺ T cell activation, proliferation and survival, amplifying psoriatic inflammation. These findings highlight the role of DGAT2 and lipid metabolism in the pathogenesis of psoriasis and reveal their interaction with immune responses in psoriasis.
Authors
Ying-Ying Li, Li-Ran Ye, Ying-Zhe Cui, Fan Xu, Xi-Bei Chen, Feng-Fei Zhang, Yi Lu, Yu-Xin Zheng, Xiao-Yong Man
Abstract
Hematopoietic stem cell transplantation (HCT) is a potentially life-saving therapy but can lead to lung injury due to chemoradiation toxicity, infection, and immune dysregulation. We previously showed that bronchoalveolar lavage (BAL) transcriptomes representing pulmonary inflammation and cellular injury can phenotype post-HCT lung injury and predict mortality. To test whether peripheral blood might be a suitable surrogate for BAL, we compared 210 paired BAL and blood transcriptomes obtained from 166 pediatric HCT patients at 27 hospitals. BAL and blood RNA abundance showed minimal correlation at the level of individual genes, gene set enrichment scores, imputed cell fractions, and T- and B-cell receptor clonotypes. Instead, we identified significant site-specific transcriptional programs. In BAL, pathways related to immunity, hypoxia, and epithelial mesenchymal transition were tightly co-expressed and linked to mortality. In contrast, in blood, expression of endothelial injury, DNA repair, and cellular metabolism pathways was associated with mortality. Integration of paired BAL and blood transcriptomes dichotomized patients into two groups with significantly different rates of hypoxia and clinical outcomes within 1 week of BAL. These findings reveal a compartmentalized injury response, where BAL and blood transcriptomes provide distinct but complementary insights into local and systemic mechanisms of post-HCT lung injury.
Authors
Emma M. Pearce, Erica Evans, Madeline Y. Mayday, Gustavo Reyes, Miriam R. Simon, Jacob Blum, Hanna Kim, Jessica Mu, Peter J. Shaw, Courtney M. Rowan, Jeffery J. Auletta, Paul L. Martin, Caitlin Hurley, Erin M. Kreml, Muna Qayed, Hisham Abdel-Azim, Amy K. Keating, Geoffrey D.E. Cuvelier, Janet R. Hume, James S. Killinger, Kamar Godder, Rabi Hanna, Christine N. Duncan, Troy C. Quigg, Paul Castillo, Nahal R. Lalefar, Julie C. Fitzgerald, Kris M. Mahadeo, Prakash Satwani, Theodore B. Moore, Benjamin Hanisch, Aly Abdel-Mageed, Dereck B. Davis, Michelle P. Hudspeth, Greg A. Yanik, Michael A. Pulsipher, Christopher C. Dvorak, Joseph L. DeRisi, Matt S. Zinter
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