Resident memory T cell development is gradual and shows AP-1 gene expression in mature cells

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Abstract

Tissue-resident memory T (TRM) cells play a central role in immune responses across all barrier tissues after infection. However, the mechanisms that drive TRM differentiation and priming for their recall effector function remains unclear. In this study, we leveraged newly generated and publicly available single-cell RNA-seq data generated across 10 developmental time points to define features of CD8+ TRM across both skin and small-intestine intraepithelial lymphocytes (siIEL). We employed linear modeling to capture gene programs that increase their expression levels in T cells transitioning from an effector to a memory state. In addition to capturing tissue-specific gene programs, we defined a temporal TRM signature across skin and siIEL that can distinguish TRM from circulating T cell populations. This TRM signature highlights biology that is missed in published signatures that compared bulk TRM to naive or nontissue resident memory populations. This temporal TRM signature included the AP-1 transcription factor family members Fos, Fosb, Fosl2, and Junb. ATAC-seq analysis detected AP-1–specific motifs at open chromatin sites in mature TRM. Cyclic immunofluorescence (CyCIF) tissue imaging detected nuclear colocalization of AP-1 members in resting CD8+ TRM greater than 100 days after infection. Taken together, these results reveal a critical role of AP-1 transcription factor members in TRM biology.

Authors

Neal P. Smith, Yu Yan, Youdong Pan, Jason B. Williams, Kasidet Manakongtreecheep, Shishir M. Pant, Jingxia Zhao, Tian Tian, Timothy Pan, Claire Stingley, Kevin Wu, Jiang Zhang, Alexander L. Kley, Peter K. Sorger, Alexandra-Chloé Villani, Thomas S. Kupper

Lipidomic profiling of human adiposomes identifies specific lipid shifts linked to obesity and cardiometabolic risk

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Abstract

BACKGROUND Obesity, a growing health concern, often leads to metabolic disturbances, systemic inflammation, and vascular dysfunction. Emerging evidence suggests that adipose tissue-derived extracellular vesicles (adiposomes) may propagate obesity-related complications. However, their lipid composition and effect on cardiometabolic state remain unclear.METHODS This study examined the lipid composition of adiposomes in 122 participants (75 in obesity group, 47 in lean group) and its connection to cardiometabolic risk. Adiposomes were isolated via ultracentrifugation and characterized using nanoparticle tracking and comprehensive lipidomic analysis by mass spectrometry. Cardiometabolic assessments included anthropometry, body composition, glucose-insulin homeostasis, lipid profiles, inflammatory markers, and vascular function.RESULTS Compared with lean controls, individuals with obesity exhibited elevated adiposome release and shifts in lipid composition, including higher ceramides, free fatty acids, and acylcarnitines, along with reduced levels of phospholipids and sphingomyelins. These alterations strongly correlated with increased BMI, insulin resistance, systemic inflammation, and impaired vascular function. Pathway enrichment analyses highlight dysregulation in glycerophospholipid and sphingolipid metabolism, bile secretion, proinflammatory pathways, and vascular contractility. Machine-learning models utilizing adiposome lipid data accurately classified obesity and predicted cardiometabolic conditions, such as diabetes, hypertension, dyslipidemia, and liver steatosis, achieving accuracy above 85%.CONCLUSION Obesity profoundly remodels the adiposome lipid landscape, linking lipid changes to inflammation, metabolic dysfunction, and vascular impairment. These findings underscore adiposome lipids as biomarkers for obesity and related cardiometabolic disorders, supporting personalized interventions and offering therapeutic value in risk stratification and treatment.FUNDING This project was supported by NIH grants R01HL161386, R00HL140049, P30DK020595 (PI: AMM), R01DK104927, and P30DK020595 as well as by a VA Merit Award (1I01BX003382, PI: BTL).

Authors

Abeer M. Mahmoud, Imaduddin Mirza, Elsayed Metwally, Mohammed H. Morsy, Giorgia Scichilone, Monica C. Asada, Amro Mostafa, Francesco M. Bianco, Mohamed M. Ali, Mario A. Masrur, Chandra Hassan, Brian T. Layden

Identification of hypoxia-inducible factor HIF1A as a therapeutic target during SARS-CoV-2-associated lung injury

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Abstract

Hypoxia-inducible factors (HIFs) promote lung protection and pathogen eradication during acute lung injury. We therefore tested the theory that pharmacologic stabilization of HIFs dampens lung injury during SARS-CoV-2 pneumonia. Initial studies in murine SARS-CoV-2 models showed improved outcomes after treatment with the FDA-approved HIF-stabilizer vadadustat. Subsequent studies in genetic models implicated alveolar-expressed Hif1a in mediating lung protection. Therefore, we performed a randomized, double-blinded, multicenter phase 2 trial in patients admitted for SARS-CoV-2 infection and concomitant hypoxia (SpO2 ≤ 94%). Patients (n=448) were randomized to oral vadadustat (900 mg/day) or placebo for up to 14 days. Safety events were similar between the two groups. Vadadustat treatment induced surrogate HIF-target genes. The primary outcome of severe lung injury requiring high oxygen support on day 14 occurred in 43 patients in the vadadustat group and 53 patients in the placebo group (estimated probability, 13.3% vs. 16.9%). Among patients with baseline FiO2 ≥ 80% (n=106), the estimated probability of the primary outcome was 12.1% (vadadustat) vs. 79.1% (placebo), indicating an even greater benefit in patients with more severe baseline hypoxia. HIF1A is a likely therapeutic target during SARS-CoV-2-associated lung injury. Robust clinical trials of HIF stabilizers during pathogen-associated lung injury are warranted.

Authors

Bentley Bobrow, Samuel D. Luber, Paul Potnuru, Katherine Figarella, Jieun Kim, Yanyu Wang, In Hyuk Bang, David Robinson, Paulina B. Sergot, Steven K. Burke, Tingting Mills, Constanza de Dios, Robert Suchting, George W. Williams, Adit A. Ginde, Yafen Liang, Hongfang Liu, Charles Green, Marie-Francoise Doursout, Alparslan Turan, Daniel I. Sessler, Xiaoyi Yuan, Holger K. Eltzschig

Csk-mediated Src family kinase regulation dampens neutrophil infiltration during pulmonary infection

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Abstract

Neutrophil recruitment is crucial for pathogen elimination. However, precise control of the inflammatory response prevents overshooting reactions. Neutrophil activation initiates signaling resulting in integrin beta 2 (Itgb2) activation and neutrophil arrest. Src family kinases are involved in multiple cellular processes and are negatively regulated by the C-terminal Src kinase (Csk). During this study, we investigated the mechanism by which Csk regulates integrin activation and neutrophil recruitment. Here, we demonstrated that Csk deficiency in murine neutrophils resulted in increased neutrophil adhesion to the endothelium along with decreased neutrophil transmigration into inflamed tissues compared to their littermate controls. In bacterial pneumonia, infected Csk-deficient mice showed higher bacterial burdens and decreased neutrophil recruitment, while other immune cell counts and cytokine levels were not significantly different compared to control. Analyses of Csk-deficient neutrophils revealed an increased Itgb2 affinity, leading to reduced migration and intravascular crawling. Mechanistically, elevated cAMP-levels increased protein kinase A activity, which subsequently enhanced Csk activation. Csk, in turn, suppressed Src family kinases activation through phosphorylation (Y529). Hence, Csk-mediated regulation of neutrophil infiltration contributes to maintain a balanced immune response during bacterial pneumonia.

Authors

Wida Amini, Lena Schemmelmann, Jan-Niklas Heming, Marina Oguama, Katharina Thomas, Helena Block, Pia Lindental, Bernadette Bardel, Andreas Margraf, Oliver Soehnlein, Anika Cappenberg, Alexander Zarbock

Rheumatoid arthritis synovial fluid induces JAK-dependent intracellular activation of human sensory neurons

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Abstract

JAK inhibitors (JAKi) are widely used anti-inflammatory drugs. Recent data suggest JAKi have superior effects on pain reduction in rheumatoid arthritis (RA). However, the underlying mechanisms for this observation are not fully understood. We investigated whether JAKi can act directly on human sensory neurons. We analysed RNA sequencing datasets of sensory neurons and found they expressed JAK1 and STAT3. Addition of cell-free RA synovial fluid to human induced pluripotent stem cell (iPSC)-derived sensory neurons led to phosphorylation of STAT3 (pSTAT3), which was completely blocked by the JAKi tofacitinib. Compared to paired serum, RA synovial fluid was enriched for the STAT3 signalling cytokines IL-6, IL-11, LIF, IFN-alpha and IFN-beta, with their requisite receptors present in peripheral nerves post-mortem. Accordingly, these recombinant cytokines induced pSTAT3 in iPSC-derived sensory neurons. Furthermore, IL-6+sIL-6R and LIF upregulated expression of pain-relevant genes with STAT3-binding sites, an effect which was blocked by tofacitinib. LIF also induced neuronal sensitisation, highlighting this molecule as a putative pain mediator. Finally, over time, tofacitinib reduced the firing rate of sensory neurons stimulated with RA synovial fluid. Together, these data indicate that JAKi can act directly on human sensory neurons, providing a potential mechanistic explanation for their suggested superior analgesic properties.

Authors

Yuening Li, Elizabeth H. Gray, Rosie Ross, Irene Zebochin, Amy Lock, Laura Fedele, Louisa Janice Kamajaya, Rebecca J. Marrow, Sarah Ryan, Pascal Röderer, Oliver Brüstle, Susan John, Franziska Denk, Leonie S. Taams

α7nAChR on B cells directs T cell differentiation to prevent viral myocarditis

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Abstract

Patients with viral myocarditis (VMC) exhibit evident autonomic nervous system imbalance, and adverse cardiac remodeling is involved in impaired cholinergic function. The α7 nicotinic acetylcholine receptor (α7nAChR), which is a neurotransmitter receptor, exerts immunoregulatory effects. Recent advances have illuminated the evolution and functions of peripheral and cardiac B cells in heart disease. However, the role of α7nAChR expressed by B cells in the progression of VMC has not been established. We revealed the neuroimmune communication landscape in the heart and found that the phenotypes of cardiac and splenic B cells and their α7nAChR expression changed dynamically during the progression of VMC to dilated cardiomyopathy. α7nAChR on B cells serves as a negative regulator by inhibiting their proinflammatory functions and signaling pathways. B cell–specific α7nAChR deficiency exacerbated myocardial inflammation, fibrosis, and cardiac dysfunction. However, these effects were abrogated in non-B cells from mice with IL-17A knockdown. Enhanced degradation of acetylcholine leads to an imbalance in cholinergic signaling, resulting in impaired neurotransmission. The acetylcholinesterase inhibitor pyridostigmine bromide could improve cardiac remodeling and prevent the progression of VMC to the chronic phase, which was partly dependent on the α7nAChR on B cells. Our findings provide notable insights into cardiac-neural-immune communication during myocardial injury.

Authors

Jing Lu, Keren Chen, Zhihong Cen, Yanlan Huang, Yong Li, LiLi Chen, Weifeng Wu

Characterisation of a pathogenic non-migratory fibroblast population in systemic sclerosis skin

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Abstract

Fibroblasts are central to pathogenesis of systemic sclerosis (SSc). However, studies of conventional explant fibroblast cultures incompletely reflect disease biology and treatment response. We isolated a second non-migratory “resident” population of fibroblasts from skin biopsies after outgrowth of explant “migratory” cells. These non-motile resident fibroblasts were compared with migratory cells from the same biopsy, using functional studies, bulk and scRNAseq, and localised in situ by multichannel immunofluorescence. Migratory and resident fibroblast populations in SSc showed distinct pro-fibrotic characteristics and gene expression for pathogenic pathways differing by stage and autoantibody subgroup. TGFβ signalling was highly active in migratory fibroblasts in early stage dcSSc. Conversely, resident fibroblasts had less upregulated TGFβ signalling, especially in late dcSSc. Increased chemokine expression was a hallmark of resident fibroblasts at all stages. In vitro studies confirmed differential response to TGFβ1 and CCL2 between migratory and resident cells. We suggest that migratory fibroblasts are especially important in early skin disease whereas non-migratory fibroblasts may have a regulatory role and contribute more to fibrosis in later stage disease. Thus, we have identified a pathogenic fibroblast population in SSc, not isolated by conventional explant culture, that could play an important role in fibrosis and be targeted therapeutically.

Authors

Kristina E.N. Clark, Shiwen Xu, Moustafa Attar, Voon H. Ong, Christopher D. Buckley, Christopher P. Denton

Residence of mice in metabolic cages reduces experimental kidney inflammation through stress-induced glucocorticoids

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Abstract

Authors

Junping Yin, Melanie Eichler, Clivia Lisowski, Jian Li, Sibylle von Vietinghoff, Natalio Garbi, Qi Mei, Anne-Kathrin Gellner, Christian Kurts

Klf9 promotes the repair of myocardial infarction by regulating macrophage recruitment and polarization

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Abstract

The inflammatory response after myocardial infarction (MI) is a precisely regulated process that greatly affects subsequent wound healing and remodeling. However, the understood about the process are still limited. Macrophages are critically involved in inflammation resolution after MI. Krüppel-like factor 9 (Klf9) is a C2H2 zinc finger-containing transcription factor that has been implicated in glucocorticoid regulation of macrophages. However, the contribution of Klf9 to macrophage phenotype and function in the context of MI remains unclear. Our study revealed that KLF9 deficiency results in higher mortality and cardiac rupture rate, as well as a considerable exacerbation in cardiac function. Single-cell RNA sequencing and flow cytometry analyses reveals that, compared to WT mice, Klf9-/- mice display excessive neutrophil infiltration, insufficient macrophage infiltration, and a reduced proportion of Monocyte-derived CD206+ macrophages post-MI. Moreover, the expression of IFN-γ-STAT1 pathway genes in Klf9-/- cardiac macrophages is dysregulated, characterized by insufficient expression at 1 day post-MI and excessive expression at day 3 post-MI. Mechanistically, Klf9 directly binds to the promoters of Stat1 gene, regulating its transcription. Overall, these findings indicates that Klf9 beneficially influences wound healing after MI through modulating macrophage recruitment and differentiation by regulating the IFN-γ-STAT1 signal pathway.

Authors

Sheng Xu, Hao Li, Jun Han, Yawei Xu, Niannian Li, Wenliang Che, Feng Liu, Wenhui Yue

CFTR negatively reprograms Th2 cell responses and CFTR potentiation restrains allergic airway inflammation

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Abstract

Type 2 inflammatory diseases are common in cystic fibrosis (CF) including asthma, sinusitis, and allergic bronchopulmonary aspergillosis. CD4+ T helper 2 (Th2) cells promote these diseases through secretion of IL-4, IL-5, and IL-13. Whether the cystic fibrosis transmembrane conductance regulator (CFTR), the mutated protein in CF, has a direct effect on Th2 development is unknown. Using murine models of CFTR deficiency and human CD4+ T cells, we show CD4+ T cells expressed Cftr transcript and CFTR protein following activation. Loss of T cell CFTR expression increased Th2 cytokine production compared to control cells. Mice with CFTR-deficient T cells developed increased allergic airway disease to Alternaria alternata extract compared to control mice. Culture of CFTR-deficient Th2 cells demonstrated increased IL-4Rα expression and increased sensitivity to IL-4 with greater induction of GATA3 and IL-13 compared to control Th2 cell cultures. The CFTR potentiator ivacaftor reduced allergic inflammation and type 2 cytokine secretion in bronchoalveolar lavage of “humanized” CFTR mice following Alternaria alternata extract challenge and decreased Th2 development in human T cell culture. Together, these data support a direct role of CFTR in regulating T cell sensitivity to IL-4 and demonstrate a potential CFTR-specific therapeutic strategy for Th2 cell-mediated allergic disease.

Authors

Mark Rusznak, Christopher M. Thomas, Jian Zhang, Shinji Toki, Weisong Zhou, Masako Abney, Danielle M. Yanda, Allison E. Norlander, Craig A. Hodges, Dawn C. Newcomb, Mark H. Kaplan, R. Stokes Peebles Jr., Daniel P. Cook