Plasma IL-6 is elevated after myocardial infarction (MI) and is associated with increased morbidity and mortality. Which cardiac cell type preferentially contributes to IL-6 and how its production is regulated is largely unknown. Here, we studied the cellular source and purinergic regulation of IL-6 formation in a murine MI model. IL-6, measured in various cell types in post MI hearts by qPCR, RNAscope and at protein level, was preferentially formed by fibroblasts (CFs). scRNAseq in infarcted mouse and human hearts confirmed this finding. Adenosine stimulated fibroblast IL-6 formation via A2bR in a Gq-dependent manner. CFs highly expressed Adora2b, rapidly degraded extracellular ATP to AMP but lacked CD73. In mice and humans Adora2B was also mainly expressed by fibroblasts (scRNAseq). Global IL-6 formation was assessed in isolated hearts in mice lacking CD73 on T-cells (CD4CD73-/-) a condition known to be associated with adverse cardiac remodeling. The ischemia-induced release of IL-6 was strongly attenuated in CD4CD73-/- mice, suggesting adenosine-mediated modulation. Together this demonstrates that post-MI IL-6 is mainly derived from activated CFs and is controlled by T-cell derived adenosine. Purinergic metabolic cooperation between CFs and T-cells is a novel mechanism with therapeutic potential which modulates IL6 formation by the heart.
Christina Alter, Anne Sophie Henseler, Christoph Owenier, Julia Hesse, Zhaoping Ding, Tobias Lautwein, Jasmin Bahr, Sikander Hayat, Rafael Kramann, Eva Kostenis, Jürgen Scheller, Jürgen Schrader
Dysfunction of vascular endothelial cells (ECs) facilitates imbalanced immune responses and tissue hyperinflammation. However, the heterogeneous functions of skin ECs and their underlying mechanism in dermatoses remain to be solved. Here, focusing on the pathogenic role of skin ECs in psoriasis, we characterized the molecular and functional heterogeneity of skin ECs from healthy individuals and psoriasis patients at the single-cell level. We found that endothelial glycocalyx destruction, a major feature of EC dysfunction in psoriasis, was a driving force during the process of T cell extravasation. Interestingly, we identified a skin EC subset, IGFBP7high ECs, in psoriasis. This subset actively responded to psoriatic-related cytokine signaling, secreted IGFBP7, damaged the endothelial glycocalyx, exposed the adhesion molecules underneath, and prepared the endothelium for immune cell adhesion and transmigration, thus aggravating skin inflammation. More importantly, we provided evidence in a psoriasis-like mouse model that anti-IGFBP7 treatment showed promising therapeutic effects for restoring the endothelial glycocalyx and alleviating skin inflammation. Taken together, our results depicted the distinct functions of EC clusters in healthy and psoriatic skin, identified IGFBP7high ECs as an active subset modulating vascular function and cutaneous inflammation, and indicated that targeting IGFBP7 is a potential therapeutic strategy in psoriasis.
Qingyang Li, Shuai Shao, Zhenlai Zhu, Jiaoling Chen, Junfeng Hao, Yaxing Bai, Bing Li, Erle Dang, Gang Wang
Uncontrolled inflammation occurred in sepsis results in multiple organ injuries and shock, which contributes to the death of sepsis patients. However, the regulatory mechanisms that restrict excessive inflammation are still elusive. Here we identified an immunoglobulin-like receptor called Signaling Lymphocyte Activation Molecular Family-7 (SLAMF7), as a key suppressor of inflammation during sepsis. We found that the expression of SLAMF7 on monocytes/ macrophages was significantly elevated in patients with sepsis and septic mice. SLAMF7 attenuated TLR-dependent MAPK and NF-κB signaling activation in macrophages by co-operating with Src homology 2-containing inositol ‑5'‑ phosphatase1 (SHIP1). Furthermore, SLAMF7 interacted with SHIP1 and TNF receptor associated factor 6 (TRAF6) to inhibit K63 ubiquitination of TRAF6. In addition, we found that tyrosine phosphorylation sites within the intracellular domain of SLAMF7 and the phosphatase domain of SHIP1 were indispensable for the interaction of SLAMF7/SHIP1/TRAF6 and SLAMF7-mediated modulation of cytokine production. Finally, we demonstrated that SLAMF7 protected against lethal sepsis and endotoxemia by down-regulating macrophage pro-inflammatory cytokines and suppressing inflammation-induced organ damage. Taken together, our findings reveal a negatively regulatory role of SLAMF7 in polymicrobial sepsis, which provides sights into the treatment of sepsis.
Yongjian Wu, Qiaohua Wang, Miao Li, Juanfeng Lao, Huishu Tang, Siqi Ming, Minhao Wu, Sitang Gong, Linhai Li, Lei Liu, Xi Huang
Signaling driven by nucleic acid sensors participates in interferonopathy-mediated autoimmune diseases. NLRP12, a pyrin-containing NLR protein, is a negative regulator of innate immune activation and type I interferon (IFN-I) production. Peripheral blood mononuclear cells (PBMCs) derived from systemic lupus erythematosus (SLE) patients expressed lower levels of NLRP12, with an inverse correlation with IFNA expression and high disease activity. NLRP12 expression was transcriptionally suppressed by runt-related transcription factor 1–dependent (RUNX1-dependent) epigenetic regulation under IFN-I treatment, which enhanced a negative feedback loop between low NLRP12 expression and IFN-I production. Reduced NLRP12 protein levels in SLE monocytes was linked to spontaneous activation of innate immune signaling and hyperresponsiveness to nucleic acid stimulations. Pristane-treated Nlrp12–/– mice exhibited augmented inflammation and immune responses; and substantial lymphoid hypertrophy was characterized in NLRP12-deficient lupus-prone mice. NLRP12 deficiency mediated the increase of autoantibody production, intensive glomerular IgG deposition, monocyte recruitment, and the deterioration of kidney function. These were bound in an IFN-I signature–dependent manner in the mouse models. Collectively, we reveal a remarkable link between low NLRP12 expression and lupus progression, which suggests the impact of NLRP12 on homeostasis and immune resilience.
Yen-Po Tsao, Fang-Yu Tseng, Chih-Wei Chao, Ming-Han Chen, Yi-Chen Yeh, Babamale Olarewaju Abdulkareem, Se-Yi Chen, Wen-Ting Chuang, Pei-Ching Chang, I-Chun Chen, Pin-Hsuan Wang, Chien-Sheng Wu, Chang-Youh Tsai, Szu-Ting Chen
Multiple sclerosis (MS) is a progressive inflammatory-demyelinating disease of the central nervous system. Increasing evidence suggests that vulnerable neurons in MS exhibit fatal metabolic exhaustion over time, a phenomenon hypothesized to be caused by chronic hyperexcitability. Axonal Kv7 (outward rectifying) and oligodendroglial Kir4.1 (inward rectifying) potassium channels have important roles in regulating neuronal excitability at and around nodes of Ranvier. Here, we studied the spatial and functional relationship between neuronal Kv7 and oligodendroglial Kir4.1 channels and assessed the transcriptional and functional signatures of cortical and retinal projection neurons under physiological and inflammatory-demyelinating conditions. We found that both channels became dysregulated in MS and experimental autoimmune encephalomyelitis (EAE) with Kir4.1 channels being chronically downregulated and Kv7 channel subunits being transiently upregulated during inflammatory demyelination. Further, we observed that pharmacological Kv7 channel opening with retigabine reduced neuronal hyperexcitability in human and EAE neurons, improved clinical EAE signs and rescued neuronal pathology in oligodendrocyte-Kir4.1-deficient mice. In summary, our findings indicate that neuron-oligodendrocyte compensatory interactions promote resilience through Kv7 and Kir4.1 channels and suggest pharmacological activation of nodal Kv7 channels as a neuroprotective strategy against inflammatory demyelination.
Hannah Kapell, Luca Fazio, Julia Dyckow, Sophia Schwarz, Andrés Cruz-Herranz, Christina Mayer, Joaquin Campos, Elisa D´Este, Wiebke Möbius, Christian Cordano, Anne-Katrin Pröbstel, Marjan Gharagozloo, Amel Zulji, Venu Narayanan Naik, Anna-Katharina Delank, Manuela Cerina, Thomas Müntefering, Celia Lerma-Martin, Jana K. Sonner, Jung H. Sin, Paul Disse, Nicole Rychlik, Khalida Sabeur, Manideep Chavali, Rajneesh Srivastava, Matthias Heidenreich, Kathryn C. Fitzgerald, Guiscard Seebohm, Christine Stadelmann, Bernhard Hemmer, Michael Platten, Thomas J. Jentsch, Maren Engelhardt, Thomas Budde, Klaus-Armin Nave, Peter A. Calabresi, Manuel A. Friese, Ari J. Green, Claudio Acuna, David H. Rowitch, Sven G. Meuth, Lucas Schirmer
BACKGROUND. Assessing circadian rhythmicity from infrequently sampled data is challenging, however this type of data is often encountered when measuring circadian transcripts in hospitalised patients. METHODS. We present ClinCirc. This method combines two existing mathematical methods (Lomb-Scargle periodogram and cosinor) sequentially, and is designed to measure circadian oscillations from infrequently sampled clinical data. The accuracy of this method was compared against 9 other methods using simulated and frequently sampled biological data. ClinCirc was then evaluated in 13 ICU patients as well as in a separate cohort of 29 kidney transplant recipients. Finally, the consequences of circadian alterations were investigated in a retrospective cohort of 726 kidney transplant recipients. RESULTS. ClinCirc had comparable performance to existing methods for analysing simulated data or clock transcript expression of healthy volunteers. It had improved accuracy compared to the cosinor method in evaluating circadian parameters in PER2::luc cell lines. In ICU patients, it was the only method investigated to suggest that loss of circadian oscillations in the peripheral oscillator was associated with inflammation, a feature widely reported in animal models. Additionally, ClinCirc was able to detect other circadian alterations, including a phase shift following kidney transplantation that was associated with the administration of glucocorticoids. This phase shift could explain why a significant complication of kidney transplantation (delayed graft dysfunction) oscillates according to the time-of-day kidney transplantation is performed. CONCLUSION. ClinCirc analysis of the peripheral oscillator reveals important clinical associations in hospitalised patients. FUNDING. UKRI, NIHR, EPSRC, NIAA, Asthma+Lung UK, Kidneys for Life.
Peter S. Cunningham, Gareth B. Kitchen, Callum Jackson, Stavros Papachristos, Thomas Springthorpe, David van Dellen, Julie E. Gibbs, Timothy W. Felton, Anthony J. Wilson, Jonathan Bannard-Smith, Martin K. Rutter, Thomas House, Paul Dark, Titus Augustine, Ozgur E. Akman, Andrew L. Hazel, John F. Blaikley
BACKGROUND Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) plays an important role in the clearance of pathological amyloid-β (Aβ) in Alzheimer’s disease (AD). This study aimed to explore sTREM2 as a central and peripheral predictor of the conversion from mild cognitive impairment (MCI) to AD.METHODS sTREM2 and Aβ1–42 levels in cerebrospinal fluid (CSF) and florbetapir-PET (AV45) images were analyzed for healthy control (HCs), patients with MCI, and patients with AD from the ADNI database. Peripheral plasma sTREM2 and Aβ1–42 levels were determined for our Neurology database of Ruijin Hospital for Alzheimer’s Disease (NRHAD) cohort, and patients with MCI were reevaluated at follow-up visits to assess for progression to AD. The association between CSF and plasma sTREM2 levels was analyzed in data from the Chinese Alzheimer’s Biomarker and Lifestyle (CABLE) database.RESULTS The results showed that patients with MCI who had low levels of CSF sTREM2 and Aβ1–42 were more likely to develop AD. Among participants with positive Aβ deposition, as assessed by AV45 imaging, elevated CSF sTREM2 levels were associated with a decreased risk of MCI-to-AD conversion. Meanwhile, in the NRHAD cohort, individuals in the MCI group with high sTREM2 levels in plasma were at a greater risk for AD, whereas low Aβ1–42 with high sTREM2 levels in plasma were associated with a faster cognitive decline. In addition, CSF sTREM2 levels were highly correlated with plasma sTREM2 levels in the CABLE database.CONCLUSION These findings suggest that sTREM2 may be useful as a potential predictive biomarker of MCI-to-AD conversion.FUNDING This study was supported by grants from the National Natural Science Foundation of China (grant nos. 82001341, 82071415, 81873778, and 82201392); the Shanghai Sailing Program (grant no. 22YF1425100); and the China Postdoctoral Science Foundation funded project (grant no. 2021M702169).
Aonan Zhao, Yang Jiao, Guanyu Ye, Wenyan Kang, Lan Tan, Yuanyuan Li, Yulei Deng, Jun Liu, for the Alzheimer’s Disease Neuroimaging Initiative (ADNI)
BACKGROUND. The kynurenine pathway (KP) has been identified as a potential mediator linking acute illness to cognitive dysfunction by generating neuroactive metabolites in response to inflammation. Delirium (acute confusion) is a common complication of acute illness and is associated with increased risk of dementia and mortality. However, the molecular mechanism underlying delirium, particularly in relation to the KP, remain elusive. METHODS. We undertook a multi-center observational study with 586 hospitalized patients (248 with delirium) and investigated associations between delirium and KP metabolites measured in cerebrospinal fluid (CSF) and serum by targeted metabolomics. We also explored associations between KP metabolites and markers of neuronal damage and one-year mortality. RESULTS. In delirium, we found concentrations of the neurotoxic metabolite quinolinic acid in CSF (CSF-QA, OR 2.26 [1.78, 2.87], p<0.001) to be increased, as well as increases in several other KP metabolites in serum and CSF. In addition, CSF-QA was associated with the neuronal damage marker neurofilament light chain (NfL, β 0.43, p<0.001) and was a strong predictor of one-year mortality (HR 4.35 [2.93, 6.45] for CSF-QA ≥ 100 nmol/L, p<0.001). The associations between CSF-QA and delirium, neuronal damage, and mortality remained highly significant following adjustment for confounders and multiple comparisons. CONCLUSION. Our data identified how systemic inflammation, neurotoxicity, and delirium are strongly linked via the KP, and should inform future delirium prevention and treatment clinical trials that target enzymes of the KP. FUNDING. Norwegian Health Association and the South-Eastern Norway Regional Health Authorities
Leiv Otto Watne, Christian Thomas Pollmann, Bjorn Erik Neerland, Else Quist-Paulsen, Nathalie Bodd Halaas, Ane-Victoria Idland, Bjørnar Hassel, Kristi Henjum, Anne-Brita Knapskog, Frede Frihagen, Johan Raeder, Aasmund Godø, Per Magne Ueland, Adrian McCann, Wender Figved, Geir Selbæk, Henrik Zetterberg, Evandro Fei Fang, Marius Myrstad, Lasse M. Giil
BACKGROUND. Acute febrile neutrophilic dermatosis (Sweet syndrome) is a potentially fatal multiorgan inflammatory disease characterized by fever, leukocytosis, and a rash with a neutrophilic infiltrate. Disease pathophysiology remains elusive, and current dogma suggests Sweet syndrome is a “reactive” process to an unknown antigen. Corticosteroids and steroid-sparing agents remain front-line therapies, but refractory cases pose a clinical challenge. METHODS. A 51-year-old woman with multiorgan Sweet syndrome developed serious corticosteroid-related side effects and was refractory to steroid-sparing agents. Blood counts, liver enzymes, and skin histopathology supported the diagnosis. Whole genome sequencing, transcriptomic profiling, and cellular assays of patient’s skin and neutrophils were performed. RESULTS. We identified elevated IL-1 signaling in lesional Sweet syndrome skin caused by a PIK3R1 gain-of-function mutation specifically found in neutrophils. This mutation increased neutrophil migration towards IL-1β and neutrophil respiratory burst. Targeted treatment with an IL-1R1 antagonist in the patient resulted in a dramatic therapeutic response and enabled tapering of corticosteroids. CONCLUSIONS. Dysregulated PI3K-AKT signaling is the first signaling pathway linked to Sweet syndrome and suggests Sweet syndrome may be caused by acquired mutations that modulate neutrophil function. Moreover, integration of molecular data across multiple levels identified a distinct subtype within a heterogenous disease that resulted in a rational and successful clinical intervention. Future cases will benefit from efforts to identify potential mutations. The ability to directly interrogate diseased skin allows this method to be generalizable to other inflammatory diseases and demonstrates a potential personalized medicine approach for challenging patients. FUNDING Berstein Foundation, NIH, VA, Moseley Foundation, and H.T. Leung Foundation.
Shreya Bhattacharya, Sayon Basu, Emily Sheng, Christina M. Murphy, Jenny Wei, Anna E. Kersh, Caroline A. Nelson, Joshua S. Bryer, Hovik A. Ashchyan, Katherine T. Steele, Amy K. Forrestel, John T. Seykora, Robert G. Micheletti, William D. James, Misha Rosenbach, Thomas H. Leung
Platelets and megakaryocytes are critical players in immune responses. Recent reports suggest infection and inflammation alter the megakaryocyte and platelet transcriptome to induce altered platelet reactivity. We examined if non-viral sepsis induces differential platelet gene expression and reactivity. Non-viral sepsis upregulated IFITM3, an interferon responsive gene that restricts viral replication. As IFITM3 has been linked to clathrin-mediated endocytosis, we examined if IFITM3 promoted endocytosis of alpha granule proteins. Interferon stimulation enhanced fibrinogen endocytosis in megakaryocytes and platelets from Ifitm+/+ mice, but not Ifitm-/- mice. IFITM3 overexpression or deletion in megakaryocytes demonstrated IFITM3 was necessary and sufficient to regulate fibrinogen endocytosis. Mechanistically, IFITM3 interacts with clathrin and αIIb and altered their plasma membrane localization into lipid rafts. In vivo interferon administration increased fibrinogen endocytosis, platelet reactivity, and thrombosis in an IFITM-dependent manner. In contrast, Ifitm-/- mice were completely rescued from interferon-induced platelet hyperreactivity and thrombosis. During murine sepsis, platelets from Ifitm+/+ mice demonstrated increased fibrinogen content and platelet reactivity, which was dependent on interferon-alpha and IFITMs. Platelets from patients with non-viral sepsis had increases in platelet IFITM3 expression, fibrinogen content, and hyperreactivity. These data identify IFITM3 as a regulator of platelet endocytosis, hyperreactivity, and thrombosis during inflammatory stress.
Robert A. Campbell, Bhanu Kanth Manne, Meenakshi Banerjee, Elizabeth A. Middleton, Abigail Ajanel, Hansjorg Schwertz, Frederik Denorme, Chris Stubben, Emilie Montenont, Samantha Saperstein, Lauren Page, Neal D. Tolley, Diana L. Lim, Samuel M. Brown, Colin K. Grissom, Douglas W. Sborov, Anandi Krishnan, Matthew T. Rondina
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