Neutrophils prevent rectal bleeding in ulcerative colitis by peptidyl-arginine deiminase-4-dependent immunothrombosis

Gut ◽  
2021 ◽  
pp. gutjnl-2021-324725
Author(s):  
Moritz Leppkes ◽  
Aylin Lindemann ◽  
Stefanie Gößwein ◽  
Susanne Paulus ◽  
Dominik Roth ◽  
...  

ObjectiveBleeding ulcers and erosions are hallmarks of active ulcerative colitis (UC). However, the mechanisms controlling bleeding and mucosal haemostasis remain elusive.DesignWe used high-resolution endoscopy and colon tissue samples of active UC (n = 36) as well as experimental models of physical and chemical mucosal damage in mice deficient for peptidyl-arginine deiminase-4 (PAD4), gnotobiotic mice and controls. We employed endoscopy, histochemistry, live-cell microscopy and flow cytometry to study eroded mucosal surfaces during mucosal haemostasis.ResultsErosions and ulcerations in UC were covered by fresh blood, haematin or fibrin visible by endoscopy. Fibrin layers rather than fresh blood or haematin on erosions were inversely correlated with rectal bleeding in UC. Fibrin layers contained ample amounts of neutrophils coaggregated with neutrophil extracellular traps (NETs) with detectable activity of PAD. Transcriptome analyses showed significantly elevated PAD4 expression in active UC. In experimentally inflicted wounds, we found that neutrophils underwent NET formation in a PAD4-dependent manner hours after formation of primary blood clots, and remodelled clots to immunothrombi containing citrullinated histones, even in the absence of microbiota. PAD4-deficient mice experienced an exacerbated course of dextrane sodium sulfate-induced colitis with markedly increased rectal bleeding (96 % vs 10 %) as compared with controls. PAD4-deficient mice failed to remodel blood clots on mucosal wounds eliciting impaired healing. Thus, NET-associated immunothrombi are protective in acute colitis, while insufficient immunothrombosis is associated with rectal bleeding.ConclusionOur findings uncover that neutrophils induce secondary immunothrombosis by PAD4-dependent mechanisms. Insufficient immunothrombosis may favour rectal bleeding in UC.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bensheng Wu ◽  
Qing Zhou ◽  
Zongqi He ◽  
Xiaopeng Wang ◽  
Xueliang Sun ◽  
...  

Background. The flower of Abelmoschus manihot (AM) has been widely used in the treatment of chronic inflammatory diseases, including ulcerative colitis. This paper aimed to confirm the therapeutic effect of AM on ulcerative colitis (UC) and explore its mechanism. Methods. Mouse models were induced by 2.5% dextran sulfate sodium (DSS) and treated with AM. UC signs, symptoms, colon macroscopic lesion scores, and disease activity index (DAI) scores were observed. Colon levels of interleukin- (IL-) 6, IL-1β, IL-18, IL-17, tumor necrosis factor- (TNF-) α, and IL-10 were quantified by ELISA. The colon protein expression levels of NLRP3, ASC, caspase 1 p10, β-arrestin1, ZO-1, occludin-1, and claudin-1 were examined by immunohistochemistry and western blotting. The mRNA levels of IL-1β, IL-18, NLRP3, ASC, and caspase 1 p10 in the colon were determined by real-time quantitative polymerase chain reaction (qPCR). Results. After treatment with AM, the mortality of mice, pathological damage to the colon, splenomegaly, and the spleen coefficient were decreased. AM reduced the levels of proinflammatory cytokines (IL-6, IL-1β, IL-18, IL-17, and TNF-α) and increased the level of IL-10. The mRNA expression levels of NLRP3, ASC, and caspase 1 in colon tissue were decreased by AM in a dose-dependent manner. In addition, AM also reduced the protein expression of NLRP3, ASC, caspase 1 p10, IL-1β, IL-18, and β-arrestin1 in the colon tissue of model mice. Western blot analysis confirmed that AM increased the expression of occludin-1, claudin-1, and ZO-1 in a dose-dependent manner. Conclusion. This study shows that AM has a significant therapeutic effect on mice with UC, and the mechanism may be related to the inhibition of the β-arrestin1/NLRP3 inflammasome signaling pathway and the protection of intestinal barrier function.


Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3607
Author(s):  
Adrian Catinean ◽  
Maria Adriana Neag ◽  
Kiran Krishnan ◽  
Dana Maria Muntean ◽  
Corina Ioana Bocsan ◽  
...  

In inflammatory bowel disease (IBD), experimental models have proven to be important tools for evaluating potential therapeutic agents and for investigating the mechanisms of pathogenesis. Oxidative stress and the immune response have been associated with acetic acid (AA)-induced ulcerative colitis (UC). Our study aimed to evaluate, for the first time, the ability of a spore-based probiotic and an amino acid and immunoglobulin supplement in reducing tissue damage and inflammatory responses in an experimental animal model of UC. Forty-two Wistar rats were divided into six groups, receiving 1% carboxymethylcellulose, 4% AA, MegaSporeBiotic™ (MSB; 1 × 109 colony forming units/day) and MegaMucosa™ (MM; 70 mg/100 g/day). Pretreatment with MSB or MM alone and in combination significantly lowered inflammation and reduced damage to the colonic mucosa. Pretreatment with these agents resulted in levels of proinflammatory cytokines, vascular tight junction proteins, and measures of oxidative stress similar to those reported for methylprednisolone, one of the first-line therapies for moderate to severe activity of UC. The protection was further confirmed by histologic analysis of the colon tissue. In conclusion, pretreatment with probiotic spore-forming Bacillus strains and a supplement of amino acids in combination with immunoglobulins exhibited anti-inflammatory and antioxidant effects in an AA-induced rat model of UC.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Temitayo O. Idowu ◽  
Valerie Etzrodt ◽  
Thorben Pape ◽  
Joerg Heineke ◽  
Klaus Stahl ◽  
...  

Abstract Background Reduced endothelial Tie2 expression occurs in diverse experimental models of critical illness, and experimental Tie2 suppression is sufficient to increase spontaneous vascular permeability. Looking for a common denominator among different critical illnesses that could drive the same Tie2 suppressive (thereby leak inducing) phenotype, we identified “circulatory shock” as a shared feature and postulated a flow-dependency of Tie2 gene expression in a GATA3 dependent manner. Here, we analyzed if this mechanism of flow-regulation of gene expression exists in vivo in the absence of inflammation. Results To experimentally mimic a shock-like situation, we developed a murine model of clonidine-induced hypotension by targeting a reduced mean arterial pressure (MAP) of approximately 50% over 4 h. We found that hypotension-induced reduction of flow in the absence of confounding disease factors (i.e., inflammation, injury, among others) is sufficient to suppress GATA3 and Tie2 transcription. Conditional endothelial-specific GATA3 knockdown (B6-Gata3tm1-Jfz VE-Cadherin(PAC)-cerERT2) led to baseline Tie2 suppression inducing spontaneous vascular leak. On the contrary, the transient overexpression of GATA3 in the pulmonary endothelium (jet-PEI plasmid delivery platform) was sufficient to increase Tie2 at baseline and completely block its hypotension-induced acute drop. On the functional level, the Tie2 protection by GATA3 overexpression abrogated the development of pulmonary capillary leakage. Conclusions The data suggest that the GATA3–Tie2 signaling pathway might play a pivotal role in controlling vascular barrier function and that it is affected in diverse critical illnesses with shock as a consequence of a flow-regulated gene response. Targeting this novel mechanism might offer therapeutic opportunities to treat vascular leakage of diverse etiologies.


Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 286
Author(s):  
Mary Frances Nakamya ◽  
Moses B. Ayoola ◽  
Leslie A. Shack ◽  
Mirghani Mohamed ◽  
Edwin Swiatlo ◽  
...  

Polyamines such as putrescine, cadaverine, and spermidine are small cationic molecules that play significant roles in cellular processes, including bacterial stress responses and host–pathogen interactions. Streptococcus pneumoniae is an opportunistic human pathogen, which causes several diseases that account for significant morbidity and mortality worldwide. As it transits through different host niches, S. pneumoniae is exposed to and must adapt to different types of stress in the host microenvironment. We earlier reported that S. pneumoniae TIGR4, which harbors an isogenic deletion of an arginine decarboxylase (ΔspeA), an enzyme that catalyzes the synthesis of agmatine in the polyamine synthesis pathway, has a reduced capsule. Here, we report the impact of arginine decarboxylase deletion on pneumococcal stress responses. Our results show that ΔspeA is more susceptible to oxidative, nitrosative, and acid stress compared to the wild-type strain. Gene expression analysis by qRT-PCR indicates that thiol peroxidase, a scavenger of reactive oxygen species and aguA from the arginine deiminase system, could be important for peroxide stress responses in a polyamine-dependent manner. Our results also show that speA is essential for endogenous hydrogen peroxide and glutathione production in S. pneumoniae. Taken together, our findings demonstrate the critical role of arginine decarboxylase in pneumococcal stress responses that could impact adaptation and survival in the host.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 317
Author(s):  
HanGoo Kang ◽  
Jinwon Seo ◽  
Eun-Jeong Yang ◽  
In-Hong Choi

Silver nanoparticles (AgNPs) are widely used in various fields because of their antimicrobial properties. However, many studies have reported that AgNPs can be harmful to both microorganisms and humans. Reactive oxygen species (ROS) are a key factor of cytotoxicity of AgNPs in mammalian cells and an important factor in the immune reaction of neutrophils. The immune reactions of neutrophils include the expulsion of webs of DNA surrounded by histones and granular proteins. These webs of DNA are termed neutrophil extracellular traps (NETs). NETs allow neutrophils to catch and destroy pathogens in extracellular spaces. In this study, we investigated how AgNPs stimulate neutrophils, specifically focusing on NETs. Freshly isolated human neutrophils were treated with 5 or 100 nm AgNPs. The 5 nm AgNPs induced NET formation, but the 100 nm AgNPs did not. Subsequently, we investigated the mechanism of AgNP-induced NETs using known inhibitors related to NET formation. AgNP-induced NETs were dependent on ROS, peptidyl arginine deiminase, and neutrophil elastase. The result in this study indicates that treatment of 5 nm AgNPs induce NET formation through histone citrullination by peptidyl arginine deiminase and histone cleavage by neutrophil elastase.


Author(s):  
Sara Notararigo ◽  
Manuel Martín-Pastor ◽  
Juan E. Viñuela Roldán ◽  
Adriano Quiroga ◽  
J. Enrique Dominguez-Munoz ◽  
...  

Abstract Inflammatory bowel disease is a multifactorial etiology, associated with environmental factors that can trigger both debut and relapses. A high level of tumor necrosis factor-α in the gut is the main consequence of immune system imbalance. The aim of treatment is to restore gut homeostasis. In this study, fresh blood and serum samples were used to identify biomarkers and to discriminate between Crohn’s disease and ulcerative colitis patients under remission treated with anti-TNF. Metabolomics based on Nuclear Magnetic Resonance spectroscopy (NMR) was used to detect unique biomarkers for each class of patients. Blood T lymphocyte repertories were characterized, as well as cytokine and transcription factor profiling, to complement the metabolomics data. Higher levels of homoserine-methionine and isobutyrate were identified as biomarkers of Crohn’s disease with ileocolic localization. For ulcerative colitis, lower levels of creatine-creatinine, proline, and tryptophan were found that reflect a deficit in the absorption of essential amino acids in the gut. T lymphocyte phenotyping and its functional profiling revealed that the overall inflammation was lower in Crohn’s disease patients than in those with ulcerative colitis. These results demonstrated that NMR metabolomics could be introduced as a high-throughput evaluation method in routine clinical practice to stratify both types of patients related to their pathology. Key messages NMR metabolomics is a non-invasive tool that could be implemented in the normal clinical practice for IBD to assess beneficial effect of the treatment. NMR metabolomics is a useful tool for precision medicine, in order to sew a specific treatment to a specific group of patients. Finding predictors of response to IFX would be desirable to select patients affected by IBD. Immunological status of inflammations correlates with NMR metabolomics biomarkers.


Author(s):  
Barry D Kyle ◽  
Terence A Agbor ◽  
Shajib Sharif ◽  
Usha Chauhan ◽  
John Marshall ◽  
...  

Abstract Background This study aimed to compare fecal calprotectin (FC) levels with other commonly used parameters as part of patient care during evaluation for inflammatory bowel disease (IBD). Methods We recruited adult IBD patients with ulcerative colitis (UC) and Crohn’s disease (CD) and compared the results of the patient’s biopsy results (i.e., inflamed versus noninflamed) for six sites (i.e., ileum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum) with concentrations of C-reactive protein (CRP), total leucocytes and fecal calprotectin (FC). Results We found that FC was significantly elevated in a concentration-dependent manner that correlated with the number of active inflammation sites reported in biopsy. Although CRP and leucocyte measurements trended upwards in line with inflammation reported from biopsy, the results were highly variable and highlighted poor reliability of these biomarkers for indicating IBD inflammation. Conclusions These results strongly suggest that FC correlates best with biopsy reports and is a superior marker than CRP and leucocytes.


Foods ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 114 ◽  
Author(s):  
Gabriel López-García ◽  
Antonio Cilla ◽  
Reyes Barberá ◽  
Amparo Alegría ◽  
María Recio

The potential anti-inflammatory effect of plant sterols (PS) enriched milk-based fruit beverages (PS, 1 g/100 mL) (MfB) with/without galactooligosaccharides (GOS, 2 g/100 mL) (MfB-G) in an experimental mice model of chronic ulcerative colitis was evaluated. Beverages were orally administered to mice every day by gavage to achieve PS and GOS doses of 35 and 90 mg/kg, respectively, and experimental colitis was induced by giving mice drinking water ad libitum containing 2% (w/v) dextran sulphate sodium (DSS) for 7 days, alternating with periods without DSS up to the end of the study (56 days). MfB beverage showed significant reduction of symptoms associated to ulcerative colitis and improved the colon shortening and mucosal colonic damage, but it was not able to reduce the increase of myeloperoxidase levels produced by DSS. MfB-G showed higher incidence of bloody feces and loss of stool consistency than MfB, as well as high levels of immune cells infiltration in colon tissue and myeloperoxidase. Therefore, PS-enriched milk-based fruit beverage could be an interesting healthy food to extend the remission periods of the diseases and the need to evaluate, in a pre-clinical model, the anti-inflammatory effect of the combination of bioactive compounds in the context of a whole food matrix.


2016 ◽  
Vol 94 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eleonora A. Starikova ◽  
Alexey V. Sokolov ◽  
Anna Yu. Vlasenko ◽  
Larisa A. Burova ◽  
Irina S. Freidlin ◽  
...  

Streptococcus pyogenes (group A Streptococcus; GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This micro-organism has developed complex virulence mechanisms to avoid the host’s defenses. We have previously reported that SDSC from GAS type M22 causes endothelial-cell dysfunction, and inhibits cell adhesion, migration, metabolism, and proliferation in a dose-dependent manner, without affecting cell viability. This work aimed to isolate and characterize a component from GAS type M22 supernatant that suppresses the proliferation of endothelial cells (EA.hy926). In the process of isolating a protein possessing antiproliferative activity we identified arginine deiminase (AD). Further study showed that this enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mmol·L–1 and 42 s−1, respectively. A distinctive feature of AD purified from GAS type M22 is that its optimum activity and the maximal rate of the catalytic process is close to neutral pH by comparison with enzymes from other micro-organisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time, in the presence of AD, the proportion of cells in G0/G1 phase increased. When l-Arg was added at increasing concentrations to the culture medium containing AD (3 μg·mL–1), the enzyme’s capacity to inhibit cell proliferation became partially depressed. The proportion of cells in phases S/G2 increased concomitantly, although the cells did not fully recover their proliferation activity. This suggests that AD from GAS type M22 has potential for the suppression of excessive cell proliferation.


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