Inflammation
Abstract
Asthma is a chronic inflammatory disease of the airways associated with excess production of Th2 cytokines and lung eosinophil accumulation. This inflammatory response persists in spite of steroid administration that blocks autocrine/paracrine loops of inflammatory cytokines, and the detailed mechanisms underlying asthma exacerbation remain unclear. Here, we show that asthma exacerbation is triggered by airway macrophages through a prion-like cell-to-cell transmission of extracellular particulates, including ASC protein, that assemble inflammasomes and mediate IL-1β production. OVA-induced allergic asthma and associated IL-1β production were alleviated in mice with small GTPase Arf6-deficient macrophages. The extracellular ASC specks were slightly engulfed by Arf6–/– macrophages, and the IL-1β production was reduced in Arf6–/– macrophages compared with that in WT macrophages. Furthermore, pharmacological inhibition of the Arf6 guanine nucleotide exchange factor suppressed asthma-like allergic inflammation in OVA-challenged WT mice. Collectively, the Arf6-dependent intercellular transmission of extracellular ASC specks contributes to the amplification of allergic inflammation and subsequent asthma exacerbation.
Authors
SangJoon Lee, Akari Ishitsuka, Takahiro Kuroki, Yu-Hsien Lin, Akira Shibuya, Tsunaki Hongu, Yuji Funakoshi, Yasunori Kanaho, Kyosuke Nagata, Atsushi Kawaguchi
Abstract
Kawasaki disease (KD) is the leading cause of acquired heart disease among children. Murine and human data suggest that the NLRP3-IL-1β pathway is the main driver of KD pathophysiology. NLRP3 can be activated during defective autophagy/mitophagy. We used the Lactobacillus casei cell wall extract (LCWE) murine model of KD vasculitis, to examine the role of autophagy/mitophagy on cardiovascular lesion development. LCWE-injected mice had impaired autophagy/mitophagy and increased levels of ROS in cardiovascular lesions, together with increased systemic 8-OHdG release. Enhanced autophagic flux significantly reduced cardiovascular lesions in LCWE-injected mice, whereas autophagy blockade increased inflammation. Vascular smooth muscle cell specific deletion of Atg16l1 and global Parkin-/- significantly increased disease formation, supporting the importance of autophagy/mitophagy in this model. Ogg1-/- mice had significantly increased lesions with increased NLRP3 activity, whereas treatment with MitoQ, reduced vascular tissue inflammation, ROS production and systemic 8-OHdG release. Treatment with MN58b or Metformin (increasing AMPK and reducing ROS), resulted in decreased disease formation. Our results demonstrate that impaired autophagy/mitophagy and ROS-dependent damage exacerbate the development of murine KD vasculitis. This pathway can be efficiently targeted to reduce disease severity. These findings enhance our understanding of KD pathogenesis and identify novel therapeutic avenues for KD treatment.
Authors
Stefanie Marek-Iannucci, A. Beyza Ozdemir, Debbie Moreira, Angela C. Gomez, Malcolm Lane, Rebecca A Porritt, Youngho Lee, Kenichi Shimada, Masanori Abe, Aleksandr Stotland, David Zemmour, Sarah Parker, Elsa Sanchez-Lopez, Jennifer Van Eyk, Roberta A. Gottlieb, Michael Fishbein, Michael Karin, Timothy R Crother, Magali Noval Rivas, Moshe Arditi
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the pandemic Coronavirus Disease 2019 (COVID-19) and now many face the burden of prolonged symptoms—long-lasting COVID-19 symptoms or “long-COVID”. Long-COVID is thought to be linked to immune dysregulation due to harmful inflammation, with the exact causes being unknown. Given the role of the microbiome in mediating inflammation, we aimed to examine the relationship between the oral microbiome and the duration of long-COVID symptoms. Tongue swabs were collected from patients presenting with symptoms concerning for COVID-19. Confirmed infections were followed until resolution of all symptoms. Bacterial composition was determined by metagenomic sequencing. We used random forest modeling to identify microbiota and clinical covariates that associated with long-COVID symptoms. Of the patients followed, 63% (17/27) developed ongoing symptomatic COVID-19 and 37% (10/27) went on to long-COVID. Patients with prolonged symptoms had significantly higher abundances of microbiota that induce inflammation, such as members of the genera Prevotella and Veillonella. Of note are species that produce lipopolysaccharides and the similarity of long-COVID patients’ oral microbiome to those of patients with chronic fatigue syndrome. All together, we our findings suggest an association with the oral microbiome and long-COVID revealing the possibility that dysfunction of the oral microbiome may contribute to this draining disease.
Authors
John P. Haran, Evan Bradley, Abigail L. Zeamer, Lindsey Cincotta, Marie-Claire Salive, Protiva Dutta, Shafik Mutaawe, Otuwe Anya, Mario Meza-Segura, Ann M. Moormann, Doyle V. Ward, Beth A. McCormick, Vanni Bucci
Abstract
Chronic obstructive pulmonary disease (COPD) is mainly caused by cigarette smoking, characterized by chronic inflammation in vulnerable individuals. However, it is unknown how genetic factors may shape chronic inflammation in COPD. To understand how hedgehog interacting protein, encoded by HHIP gene identified in the genome-wide association study in COPD, plays a role in inflammation, we utilized Hhip+/- mice that resemble persistent inflammation and emphysema observed in human COPD upon aging. By performing single cell RNA sequencing of the whole lung from mice at different ages, we found that Hhip+/- mice develop a cytotoxic immune response with a specific increase in Klrg1+CD8+T cells with upregulated Ifnγ expression recapitulating human COPD. Hhip expression was restricted to a lung fibroblast subpopulation that has increased interaction with CD8+T lymphocytes in Hhip+/- compared to Hhip+/+ during aging. Hhip-expressing lung fibroblasts have upregulated IL-18 pathway genes in Hhip+/- lung fibroblasts, which was sufficient to drive increased levels of IFNγ in CD8+T cells ex vivo. Our finding provides insight into how a common genetic variation contributes to the amplified lymphocytic inflammation in COPD.
Authors
Jeong H. Yun, ChangHee Lee, Tao Liu, Siqi Liu, Edy Y. Kim, Shuang Xu, Jeffrey L. Curtis, Luca Pinello, Russell P. Bowler, Edwin K. Silverman, Craig P. Hersh, Xiaobo Zhou
Abstract
Cell lines are the mainstay in understanding the biology of COVID-19 infection, but do not recapitulate many of the complexities of human infection. The use of human lung tissue is one solution for the study of such novel respiratory pathogens. We hypothesized that a cryopreserved bank of human lung tissue allows for the ex vivo study of the inter-individual heterogeneity of host response to SARS-CoV-2 infection, thus providing a bridge between studies with cell lines and studies in animal models. We generated a cryobank of tissues from 21 donors, many of whom had clinical risk factors for severe COVID-19. Cryopreserved tissues preserved 90% cell viability and contained heterogenous populations of metabolically active epithelial, endothelial, and immune cell subsets of the human lung. Samples were readily infectable with HCoV-OC43 and SARS-CoV-2 coronaviruses, and demonstrated comparable susceptibility to infection. In contrast, we observed a marked donor-dependent heterogeneity in the expression of IL6, CXCL8 and IFNB1 in response to SARS-CoV2 infection. Treatment of tissues with dexamethasone and the experimental drug, n-hydroxycytidine, suppressed viral growth in all samples, whereas chloroquine and remdesivir had no detectable effect. Metformin and sirolimus, molecules with predicted but unproven antiviral activity, each suppressed viral replication in tissues from a subset of donors. In summary, we developed a novel system for the ex vivo study of human SARS-CoV- 2 infection using primary human lung tissue from a library of donor tissues. This model may be useful for drug screening and for understanding basic mechanisms of COVID-19 pathogenesis.
Authors
Matthew A. Schaller, Yamini Sharma, Zadia Dupee, Duy T. Nguyen, Juan M. Urueña, Ryan A. Smolchek, Julia C. Loeb, Tiago N. Machuca, John A. Lednicky, David J. Odde, Robert F. Campbell, W. Gregory Sawyer, Borna Mehrad
Abstract
Innate immunity and chronic inflammation are involved in atherosclerosis and atherothrombosis leading to target organ damage in essential hypertension (EH). However, the role of neutrophils in EH is still elusive. We investigated the association between angiotensin II (Ang II) and neutrophil extracellular traps (NETs) in pathogenesis of EH. Plasma samples, kidney biopsies and surgical specimens of abdominal aortic aneurysms (AAA) from EH patients were used. Cell-based assays, NETs/human aortic endothelial cells co-cultures and in situ studies were performed. Increased plasma levels of NETs and tissue factor (TF) activity were detected in untreated, newly-diagnosed, EH patients. Stimulation of control neutrophils with plasma from untreated EH patients generated TF-enriched NETs promoting endothelial collagen production. Ang II induced NETosis in vitro via a reactive oxygen species (ROS)/peptidylarginine deiminase type 4 and autophagy-dependent pathway. Circulating NETs and thrombin generation levels were reduced significantly in EH patients starting treatment with Ang II receptor blockers, whereas their plasma was unable to trigger procoagulant NETs. Moreover, TF-bearing NETotic neutrophils/remnants were accumulated in sites of interstitial renal fibrosis and in the subendothelial layer of AAA. These data reveal the important pathogenic role of Ang II/ROS/NETs/TF axis in EH, linking thromboinflammation with endothelial dysfunction and fibrosis.
Authors
Akrivi Chrysanthopoulou, Eugenia Gkaliagkousi, Antonios Lazaridis, Stella Arelaki, Panagiotis Pateinakis, Maria Ntinopoulou, Alexandros Mitsios, Christina Antoniadou, Christos Argyriou, George S. Georgiadis, Vasileios Papadopoulos, Alexandra Giatromanolaki, Konstantinos Ritis, Panagiotis Skendros
Abstract
Macrophage activation syndrome (MAS) is a life-threatening cytokine storm complicating systemic juvenile idiopathic arthritis (SJIA) driven by IFNγ. SJIA and MAS are associated with an unexplained emerging lung disease (SJIA-LD), with our recent work supporting pulmonary activation of IFNγ pathways pathologically linking SJIA-LD and MAS. Our objective was to mechanistically define the novel observation of pulmonary inflammation in the TLR9 mouse model of MAS. In acute MAS, lungs exhibit mild but diffuse CD4-predominant, perivascular interstitial inflammation with elevated IFNγ, IFN-induced chemokines, and AMΦ expression of IFNγ-induced genes. Single-cell RNA-sequencing confirmed IFN-driven transcriptional changes across lung cell types with myeloid expansion and detection of MAS-specific macrophage populations. Systemic MAS resolution was associated with increased AMΦ and interstitial lymphocytic infiltration. AMΦ transcriptomic analysis confirmed IFNγ-induced proinflammatory polarization during acute MAS, which switches towards an anti-inflammatory phenotype after systemic MAS resolution. Interestingly, recurrent MAS led to increased alveolar inflammation and lung injury, and reset AMΦ polarization towards a proinflammatory state. Furthermore, in mice bearing macrophages insensitive to IFNγ, both systemic feature of MAS and pulmonary inflammation were attenuated. These findings demonstrate that experimental MAS induces IFNγ-driven pulmonary inflammation replicating key features of SJIA-LD, and provides a model system for testing novel treatments directed towards SJIA-LD.
Authors
Denny K. Gao, Nathan Salomonis, Maggie Henderlight, Christopher Woods, Kairavee Thakkar, Alexei A. Grom, Sherry Thornton, Michael B. Jordan, Kathryn A. Wikenheiser-Brokamp, Grant S. Schulert
Abstract
Hyperstimulation of the cholecystokinin receptor (CCK1R), a Gq-protein coupled receptor (GPCR), in pancreatic acinar cells is commonly used to induce pancreatitis in rodents. Human pancreatic acinar cells lack CCK1R but express cholinergic receptor muscarinic 3 (M3R), another GPCR. To test whether M3R activation is involved in pancreatitis, a mutant M3R was conditionally expressed in pancreatic acinar cells in mice. This mutant receptor loses responsiveness to its native ligand acetylcholine but can be activated by an inert small molecule, clozapine-N-oxide (CNO). Intracellular calcium and amylase were elicited by CNO in pancreatic acinar cells isolated from mutant M3R mice but not WT mice. Similarly, acute pancreatitis (AP) could be induced by a single injection of CNO in the transgenic mice but not WT mice. Compared with the cerulein-induced AP, CNO caused more widespread acinar cell death and inflammation. Furthermore, chronic pancreatitis developed at 4 weeks after 3 episodes of CNO-induced AP. In contrast, in mice with three recurrent episodes of cerulein-included AP, pancreas histology was restored in 4 weeks. Furthermore, the M3R antagonist ameliorated the severity of cerulein-induced AP in WT mice. We conclude that M3R activation can cause the pathogenesis of pancreatitis. This model may provide an alternative approach for pancreatitis research.
Authors
Jianhua Wan, Jiale Wang, Larry E. Wagner II, Oliver H. Wang, Fu Gui, Jiaxiang Chen, Xiaohui Zhu, Ashley N. Haddock, Brandy H. Edenfield, Brian Haight, Debabrata Mukhopadhyay, Ying Wang, David I. Yule, Yan Bi, Baoan Ji
Abstract
Stimulator of IFN genes (STING) activates TANK-binding kinase 1 (TBK1) and IFN regulatory factor 3 (IRF3) to produce type I IFNs. Extracellular cold-inducible RNA-binding protein (eCIRP) is released from cells during hemorrhagic shock (HS). We hypothesized that eCIRP activates STING to induce inflammation and acute lung injury (ALI) after HS. WT and STING–/– mice underwent controlled hemorrhage by bleeding, followed by fluid resuscitation. Blood and lungs were collected at 4 hours after resuscitation. Serum ALT, AST, LDH, IL-6, and IFN-β were significantly decreased in STING–/– mice compared with WT mice after HS. In STING–/– mice, the levels of pTBK1 and pIRF3, and expression of TNF-α, IL-6, and IL-1β mRNAs and proteins in the lungs, were significantly decreased compared with WT HS mice. The 10-day mortality rate in STING–/– mice was significantly reduced. I.v. injection of recombinant mouse CIRP (rmCIRP) in STING–/– mice showed a significant decrease in pTBK1 and pIRF3 and in IFN-α and IFN-β mRNAs and proteins in the lungs compared with rmCIRP-treated WT mice. Treatment of TLR4–/–, MyD88–/–, and TRIF–/– macrophages with rmCIRP significantly decreased pTBK1 and pIRF3 levels and IFN-α and IFN-β mRNAs and proteins compared with WT macrophages. HS increases eCIRP levels, which activate STING through TLR4/MyD88/TRIF pathways to exacerbate inflammation.
Authors
Kehong Chen, Joaquin Cagliani, Monowar Aziz, Chuyi Tan, Max Brenner, Ping Wang
Abstract
BACKGROUND. Epicardial adipose tissue (EAT) directly overlies the myocardium with changes in its morphology and volume associated with myriad cardiovascular and metabolic diseases. However, EAT’s immune structure and cellular characterization remain incompletely described. This study aimed to define the immune phenotype of EAT in humans, and compare such profiles across lean, obese and diabetic patients. METHODS. A total of 152 adult patients undergoing open chest coronary artery bypass grafting (CABG), valve repair/replacement (VR) surgery or combined CABG/valve surgery were recruited to the study. Patients’ clinical and biochemical data alongside epicardial adipose tissue (EAT), subcutaneous adipose tissue (SAT) and pre-operative blood samples were collected. Immune cell profiling was evaluated by flow cytometry and complemented by gene expression studies of immune mediators. Bulk RNA-seq was performed in EAT across different metabolic profiles to assess whole transcriptome changes observed in these groups. RESULTS. Flow cytometry analysis demonstrated that EAT is highly enriched in adaptive immune (T and B) cells. Whilst overweight/obese and diabetic patients had similar EAT cellular profiles to lean control patients, the EAT exhibited significantly (P≤.01) raised expression of immune mediators including: interleukin1 (IL1), IL6, tumour necrosis factorα (TNFα) and interferonγ (IFNγ). These changes were not observed in either SAT or blood. Neither underlying coronary artery disease nor the presence of hypertension significantly altered the immune profiles observed. Bulk RNA-seq demonstrated significant alterations in metabolic and inflammatory pathways in the EAT of overweight/obese patients compared with lean controls. CONCLUSIONS. Adaptive immune cells are the predominant immune cell constituent in human EAT and SAT. The presence of underlying cardiometabolic conditions, specifically obesity and diabetes, rather than cardiac disease phenotype appears to alter the inflammatory profile of EAT. Obese states markedly alter EAT metabolic and inflammatory signalling genes, underlining the impact of obesity on the EAT transcriptome profile.
Authors
Vishal Vyas, Hazel Blythe, Elizabeth G. Wood, Balraj Sandhar, Shah-Jalal Sarker, Damian Balmforth, Shirish G. Ambekar, John Yap, Stephen J. Edmondson, Carmelo Di Salvo, Kit Wong, Neil Roberts, Rakesh Uppal, Ben Adams, Alex Shipolini, Aung Y. Oo, David Lawrence, Shyam Kolvekar, Kulvinder S. Lall, Malcolm C. Finlay, M. Paula Longhi
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