Inflammations
Abstract
Necrotizing enterocolitis (NEC) is a deadly gastrointestinal disease of premature infants that is associated with an exaggerated inflammatory response, dysbiosis of the gut microbiome, decreased epithelial cell proliferation, and gut barrier disruption. We describe an in vitro model of human neonatal small intestinal epithelium (Neonatal-Intestine-on-a-Chip) that mimics key features of intestinal physiology. This model utilizes premature infant intestinal enteroids grown from surgically harvested intestinal tissue and co-cultured with human intestinal microvascular endothelial cells within a microfluidic device. We used our Neonatal-Intestine-on-a-Chip to recapitulate NEC pathophysiology by adding infant-derived microbiota. This model, named NEC-on-a-Chip, recapitulates the predominant features of NEC including significant upregulation of pro-inflammatory cytokines, decreased intestinal epithelial cell markers, reduced epithelial proliferation, and disrupted epithelial barrier integrity. NEC-on-a-Chip provides an improved preclinical model of NEC that facilitates comprehensive analysis of the pathophysiology of NEC using precious clinical samples. This model is an advance towards a personalized medicine approach to test new therapeutics for this devastating disease.
Authors
Wyatt E. Lanik, Cliff J. Luke, Lila S. Nolan, Qingqing Gong, Lauren C. Frazer, Jamie M. Rimer, Sarah E. Gale, Raymond Luc, Shay S. Bidani, Carrie A. Sibbald, Angela N. Lewis, Belgacem Mihi, Pranjal Agrawal, Martin Goree, Marlie M. Maestas, Elise Hu, David G. Peters, Misty Good
Abstract
Patients with neovascular AMD (nAMD) suffer vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Macrophages are found in CNV lesions from nAMD patients. Additionally, Ccr2-/- mice, which lack classical monocyte-derived macrophages, show reduced CNV size. However, macrophages are highly diverse cells that can perform multiple functions. We performed single-cell RNA-sequencing on immune cells from wildtype and Ccr2-/- eyes to uncover macrophage heterogeneity during the laser-induced CNV mouse model of nAMD. We identified 12 macrophage clusters, including Spp1+ macrophages. Spp1+ macrophages were enriched from wildtype lasered eyes and expressed a pro-angiogenic transcriptome via multiple pathways, including vascular endothelial growth factor signaling, endothelial cell sprouting, cytokine signaling, and fibrosis. Additionally, Spp1+ macrophages expressed the marker CD11c, and CD11c+ macrophages were increased by laser and present in CNV lesions. Finally, CD11c+ macrophage depletion reduced CNV size by 40%. These findings broaden our understanding of ocular macrophage heterogeneity and implicate CD11c+ macrophages as a potential therapeutic target for treatment-resistant nAMD patients.
Authors
Steven Droho, Amrita Rajesh, Carla M. Cuda, Harris Perlman, Jeremy A. Lavine
Abstract
Cholesterol-25-hydroxylase (CH25H), the biosynthetic enzyme for 25-hydroxycholesterol (25HC), is most highly expressed in the lung, but its role in lung biology is poorly defined. Recently, we reported that Ch25h is induced in monocyte-derived macrophages recruited to the airspace during resolution of lung inflammation and that 25HC promotes Liver X Receptor (LXR)-dependent clearance of apoptotic neutrophils by these cells. Ch25h and 25HC are, however, also robustly induced by lung-resident cells during the early hours of lung inflammation, suggesting additional cellular sources and targets. Here, using Ch25h-/- mice and exogenous 25HC in lung injury models, we provide evidence that 25HC sustains pro-inflammatory cytokines in the airspace and augments lung injury, at least in part, by inducing LXR-independent endoplasmic reticulum stress and endothelial leak. Suggesting an autocrine effect in endothelium, inhaled LPS upregulates pulmonary endothelial Ch25h and non-hematopoietic Ch25h deletion is sufficient to confer lung protection. In acute respiratory distress syndrome patients, airspace 25HC and alveolar macrophage CH25H were associated with markers of microvascular leak, endothelial activation, endoplasmic reticulum stress, inflammation, and clinical severity. Taken together, our findings suggest that 25HC deriving from and acting upon different cell types in the lung communicates distinct, temporal LXR-independent and -dependent signals to regulate inflammatory homeostasis.
Authors
Jennifer H. Madenspacher, Eric D. Morrell, Jeffrey G. McDonald, Bonne M. Thompson, Yue Li, Konstantin G. Birukov, Anna A. Birukova, Renee D. Stapleton, Aidin Alejo, Peer W. Karmaus, Julie M. Meacham, Prashant Rai, Carmen Mikacenic, Mark M. Wurfel, Michael B. Fessler
Abstract
The inability of mature retinal ganglion cells (RGCs) to regenerate axons after optic nerve injury can be partially reversed by manipulating cell-autonomous and/or -non-autonomous factors. Although manipulations of cell-non-autonomous factors could have higher translational potential than genetic manipulations of RGCs, they have generally produced lower levels of optic nerve regeneration. Here we report that preconditioning resulting from mild lens injury (conditioning LI, cLI) prior to optic nerve damage induces far greater regeneration than LI after nerve injury or the pro-inflammatory agent zymosan given either before or after nerve damage. Unlike zymosan-induced regeneration, cLI is unaltered by depleting mature neutrophils or T cells or blocking receptors for known inflammation-derived growth factors (Oncomodulin, SDF1, CCL5), and is only partly diminished by suppressing CCR2+ monocyte recruitment. Repeated episodes of LI lead to full-length optic nerve regeneration, and pharmacological removal of local resident macrophages with the colony stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 enables some axons to re-innervate the brain in just 6 weeks, comparable to the results obtained with the most effective genetic manipulations of RGCs. Thus, cell-non-autonomous interventions can induce high levels of optic nerve regeneration, paving the way to uncover potent, translatable therapeutic targets for CNS repair.
Authors
Qian Feng, Kimberly A. Wong, Larry I. Benowitz
Abstract
Macrophages intimately interact with intestinal epithelial cells, but the consequences of defective macrophage–epithelial cell interactions for protection against enteric pathogens are poorly understood. Here, we show that in mice with a deletion in protein tyrosine phosphatase nonreceptor type 2 (PTPN2) in macrophages, infection with Citrobacter rodentium, a model of enteropathogenic and enterohemorrhagic E. coli infection in humans, promoted a strong type 1/IL-22–driven immune response, culminating in accelerated disease but also faster clearance of the pathogen. In contrast, deletion of PTPN2 specifically in epithelial cells rendered the epithelium unable to upregulate antimicrobial peptides and consequently resulted in a failure to eliminate the infection. The ability of PTPN2-deficient macrophages to induce faster recovery from C. rodentium was dependent on macrophage-intrinsic IL-22 production, which was highly increased in macrophages deficient in PTPN2. Our findings demonstrate the importance of macrophage-mediated factors, and especially macrophage-derived IL-22, for the induction of protective immune responses in the intestinal epithelium, and show that normal PTPN2 expression in the epithelium is crucial to allow for protection against enterohemorrhagic E. coli and other intestinal pathogens.
Authors
Marianne R. Spalinger, Vinicius Canale, Anica Becerra, Ali Shawki, Meli’sa Crawford, Alina N. Santos, Pritha Chatterjee, Jiang Li, Meera G. Nair, Declan F. McCole
Abstract
As a hallmark for inflammatory bowel disease (IBD), elevated intestinal epithelial cell (IEC) death compromises the gut barrier, activating inflammatory response and triggering more IEC death. However, the precise intracellular machinery that prevents IEC death and break this vicious feedback remains largely unknown. Here, we report that Gab1 expression is decreased in patients with IBD and inversely correlated with IBD severity. Gab1 deficiency in intestinal epithelial cells accounts for the exacerbated colitis induced by dextran sodium sulfate (DSS) owing to sensitizing IECs to RIPK3-mediated necroptosis, which irreversibly disrupted homeostasis of the epithelial barrier and promoted intestinal inflammation. Mechanistically, Gab1 negatively regulates necroptosis signaling through inhibiting the formation of RIPK1/RIPK3 complex in response to TNF-α. Importantly, administration of RIPK3 inhibitor reveals a curative effect in epithelial Gab1-deficient mice. Further analysis indicates mice with Gab1 deletion are prone to inflammation associated colorectal tumorigenesis. Collectively, our study defines a protective role for Gab1 in colitis and colitis-driven colorectal cancer through negatively regulating RIPK3-dependent necroptosis, in which may serve as an important target to fine-tune necroptosis and intestinal inflammation-related disease.
Authors
Jiaqi Xu, Shihao Li, Wei Jin, Hui Zhou, Tingting Zhong, Xiaoqing Cheng, Yujuan Fu, Peng Xiao, Hongqiang Cheng, Di Wang, Yuehai Ke, Zhinong Jiang, Xue Zhang
Abstract
Low CC16 plasma levels are linked to accelerated lung function decline in COPD patients. Cigarette smoke (CS)-exposed Cc16-/- mice have exaggerated COPD-like disease associated with increased NF-kB activation in their lungs. It is unclear whether CC16 augmentation can reverse exaggerated COPD in CS-exposed Cc16-/- mice and whether increased NF-kB activation contributes to the exaggerated COPD in CS-exposed Cc16-/- lungs. CS-exposed WT and Cc16-/- mice were treated with recombinant human CC16 protein solution (rhCC16) or a NF-kB inhibitor (IMD0354) versus vehicle beginning at the mid-point of the exposures. COPD-like disease and NF-kB activation were measured in the lungs. RhCC16 limited the progression of emphysema, small airway fibrosis, and chronic-bronchitis-like disease in WT and Cc16-/- mice partly by reducing pulmonary inflammation (reducing myeloid leukocytes and/or increasing regulatory T and/or B cells) and alveolar septal cell apoptosis, reducing NF-kB activation in CS-exposed Cc16-/- lungs, and rescuing the reduced Foxj1 expression in CS-exposed Cc16-/- lungs. IMD0354 treatment reduced exaggerated lung inflammation and rescued the reduced Foxj1 expression in CS-exposed Cc16-/- mice. rhCC16 treatment reduced NF-kB activation in luciferase reporter A549 cells. Thus, rhCC16 treatment limits COPD progression in CS-exposed Cc16-/- mice partly by inhibiting NF-kB activation and represents a novel therapeutic approach for COPD.
Authors
Joselyn Rojas-Quintero, Maria E. Laucho-Contreras, Xiaoyun Wang, Quynh-Anh Fucci, Patrick R. Burkett, Se-Jin Kim, Duo Zhang, Yohannes Tesfaigzi, Yuhong Li, Abhiram R. Bhashyam, Li Zhang, Haider Khamas, Bartolome Celli, Aprile L. Pilon, Francesca Polverino, Caroline A. Owen
Abstract
Keloid is considered as a fibro-proliferative disease characterized by chronic inflammation that is induced following skin injury. Deciphering the underlying mechanism of keloid formation is essential for improving treatment outcomes. Here, we found that more macrophages were activated towards M2 subtype in keloid dermis when compared to normal dermis. Western Blot revealed that the level of phosphorylated STAT6, a known inducer of M2 polarization, was higher in keloid fibroblasts as opposed to fibroblasts from normal dermis. Moreover, keloid fibrosis was shown to be positively correlated with the level of phosphorylated STAT6. Further, we identified downregulation of IL13RA2, a ‘decoy’ receptor of IL13, in keloid fibroblasts compared to fibroblasts from normal dermis. Ectopic expression of IL13RA2 in keloid fibroblasts resulted in inhibition of STAT6 phosphorylation, cell proliferation, migration, invasion, extracellular matrix secretion and myofibroblast marker expression, as well as an increase in apoptosis. Consistently, knockdown of IL13RA2 in normal fibroblasts induced a ‘keloidal’ status. Furthermore, both in vitro application and intra-tumoral injection of pSTAT6 inhibitor AS1517499 in a PDX keloid-implantation mouse model, resulted in proliferation inhibition, tissue necrosis, apoptosis and myofibroblast marker reduction. Collectively, this study elucidates the key role of IL13RA2 in keloid pathology and inspire further translational research of keloid treatment concerning JAK/STAT6 inhibition.
Authors
Hua Chao, Lisheng Zheng, Pojui Hsu, Jinyun He, Ridong Wu, Shuqia Xu, Ruixi Zeng, Yuan Zhou, Huisi Ma, Haibo Liu, Qing Tang
Abstract
Neutrophils (PMN) are the first immune responders to infection/injury playing a critical role in clearing invading microbes and promoting tissue repair. However, dysregulated trafficking of PMNs across mucosal surfaces is a pathological hallmark of numerous diseases characterized by persistent or intermittent bursts of mucosal inflammation. The critical final step in PMN trafficking into mucosal lined organs (including the lungs, kidneys, skin and gut) involves transepithelial migration (TEpM). The glycoprotein CD11b/CD18 is the predominant β2 integrin that mediates PMN TEpM. Furthermore, CD11b/CD18 also regulates key PMN inflammatory effector functions that are implicated in the pathogenesis of chronic mucosal inflammation including superoxide release and degranulation. Recent studies have shown that terminal Fucose and GlcNAc glycans on CD11b/CD18 can be targeted to reduce PMN trafficking across intestinal epithelium, highlighting the importance of glycosylation in regulating PMN inflammatory function in mucosal settings. Previous studies have also demonstrated that the most abundant terminal glycan on human and murine PMN is sialic acid (Sia). However, the role of Sia in regulating PMN epithelial influx and mucosal inflammatory function is not well understood. Here we demonstrate that inhibiting sialidase mediated removal of α2-3 linked Sia from CD11b/CD18 inhibits PMN migration across intestinal epithelium in vitro and in vivo. Sialylation was also found to regulate critical PMN inflammatory effector functions including degranulation and superoxide release. Finally, we demonstrate that sialidase inhibition reduces bacterial peptide mediated CD11b/CD18 activation in PMN and blocks downstream intracellular signaling mediated by Spleen tyrosine kinase (Syk) and p38 MAP kinase. Taken together, these data demonstrate that sialylated glycans on CD11b/CD18 represent novel targets for ameliorating PMN mediated tissue damage and reducing inflammation in mucosal inflammatory disorders.
Authors
Veronica Azcutia, Matthias Kelm, Dylan Fink, Richard D. Cummings, Asma Nusrat, Charles A. Parkos, Jennifer C. Brazil
Abstract
Rosacea is a common chronic inflammatory skin disease with a fluctuating course of excessive inflammation and apparent neovascularization. Microbial dysbiosis with high density of B. oleronius and increased activity of kallikrein 5, which cleaves cathelicidin antimicrobial peptide, are key pathogenic triggers in rosacea. However, how these events are linked to the disease remains unknown. Here, we show that type I interferons produced by plasmacytoid dendritic cells represent the pivotal link between dysbiosis, the aberrant immune response, and neovascularization. Compared to other commensal bacteria, B. oleronius is highly susceptible and preferentially killed by cathelicidin antimicrobial peptides leading to enhanced generation of complexes with bacterial DNA. These bacterial DNA-complexes but not DNA-complexes derived from host cells are required for cathelicidin-induced activation of plasmacytoid dendritic cells and type I interferon production. Moreover, kallikrein 5 cleaves cathelicidin into peptides with heightened DNA-binding and type I interferon-inducing capacities. In turn, excessive type I interferon expression drives neoangiogenesis via IL22 induction and upregulation of the IL22 receptor on endothelial cells. These findings unravel a novel pathomechanism, which directly links hallmarks of rosacea to the killing of dysbiotic commensal bacteria with induction of a pathogenic type I interferon-driven and IL22-mediated angiogenesis.
Authors
Alessio A. Mylonas, Heike C. Hawerkamp, Yichen Wang, Jiaqi Chen, Francesco Messina, Olivier Demaria, Stephan Meller, Bernhard Homey, Jeremy Di Domizio, Lucia Mazzolai, Alain Hovnanian, Michel Gilliet, Curdin Conrad
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