Inhibition of gelatinase B/MMP-9 does not attenuate colitis in murine models of inflammatory bowel disease

A central role for CCR2 in monocyte recruitment and blood-brain barrier disruption during Usutu virus encephalitis

Usutu virus (USUV) is an emerging neurotropic flavivirus capable of causing encephalitis in humans. Here, our main goal was to characterize the innate immune response in the brain during USUV encephalitis and to identify strategies to control disease severity. Using an immunocompetent mouse model of USUV encephalitis, we showed that microglia activation, blood-brain barrier (BBB) disruption and inflammatory monocyte recruitment are hallmarks of disease 6 days post infection. Activated microglia were in close association to USUV-infected cells, concomitantly with elevated levels of IL-6, IFN-γ, CCL2, CCL5, CXCL10 and CXCL1 in the brain. Monocyte recruitment was CCR2-dependent and driven by IFN-γ and CCL2 production beneath the brain vasculature. Moreover, CCR2 deficiency inhibited microglia activation and BBB disruption, showing the central role of CCR2 in USUV encephalitis. Accordingly, treatment with dexamethasone prevented pro-inflammatory mediator production and reduced leukocyte recruitment significantly, restraining encephalitis severity. Concluding, USUV encephalitis is driven by CCR2-mediated monocyte recruitment and BBB disruption, and blocked therapeutically by glucocorticoids.

Common diagnostic biomarkers and molecular mechanisms of Helicobacter pylori infection and inflammatory bowel disease

Background

Helicobacter pylori (H. pylori) may be present in the intestinal mucosa of patients with inflammatory bowel disease (IBD), which is a chronic inflammation of the gastrointestinal tract. The role of H. pylori in the pathogenesis of IBD remains unclear. In this study, bioinformatics techniques were used to investigate the correlation and co-pathogenic pathways between H. pylori and IBD.

Methods

The following matrix data were downloaded from the GEO database: H. pylori-associated gastritis, GSE233973 and GSE27411; and IBD, GSE3365 and GSE179285. Differential gene analysis was performed via the limma software package in the R environment. A protein-protein interaction (PPI) network of DEGs was constructed via the STRING database. Cytoscape software, through the CytoHubba plugin, filters the PPI subnetwork and identifies Hub genes. Validation of the Hub genes was performed in the validation set. Immune analysis was conducted via the CIBERSORT algorithm. Transcription factor interaction and small molecule drug analyses of the Hub genes were also performed.

Results

Using the GSE233973 and GSE3365 datasets, 151 differentially expressed genes (DEGs) were identified. GO enrichment analysis revealed involvement in leukocyte migration and chemotaxis, response to lipopolysaccharides, response to biostimulatory stimuli, and regulation of interleukin-8 (IL-8) production. Ten Hub genes (TLR4, IL10, CXCL8, IL1B, TLR2, CXCR2, CCL2, IL6, CCR1 and MMP-9) were identified via the PPI network and Cytoscape software. Enrichment analysis of the Hub genes focused on the lipopolysaccharide response, bacterial molecular response, biostimulatory response and leukocyte movement. Validation using the GSE27411 and GSE179285 datasets revealed that MMP-9 was significantly upregulated in both the H. pylori and IBD groups. The CIBERSORT algorithm revealed immune infiltration differences between the control and disease groups of IBD patients. Additionally, the CMap database identified the top 11 small molecule compounds across 10 cell types, including TPCA-1, AS-703026 and memantine, etc.

Conclusion

Our study revealed the co-pathogenic mechanism between H. pylori and IBD and identified 10 Hub genes related to cellular immune regulation and signal transduction. The expression of MMP-9 is significantly upregulated in both H. pylori infection and IBD. This study provides a new perspective for exploring the prevention and treatment of H. pylori infection and IBD.

Current understanding of the interplay between extracellular matrix remodelling and gut permeability in health and disease

The intestinal wall represents an interactive network regulated by the intestinal epithelium, extracellular matrix (ECM) and mesenchymal compartment. Under healthy physiological conditions, the epithelium undergoes constant renewal and forms an integral and selective barrier. Following damage, the healthy epithelium is restored via a series of signalling pathways that result in remodelling of the scaffolding tissue through finely-regulated proteolysis of the ECM by proteases such as matrix metalloproteinases (MMPs). However, chronic inflammation of the gastrointestinal tract, as occurs in Inflammatory Bowel Disease (IBD), is associated with prolonged disruption of the epithelial barrier and persistent damage to the intestinal mucosa. Increased barrier permeability exhibits distinctive signatures of inflammatory, immunological and ECM components, accompanied by increased ECM proteolytic activity. This narrative review aims to bring together the current knowledge of the interplay between gut barrier, immune and ECM features in health and disease, discussing the role of barrier permeability as a discriminant between homoeostasis and IBD.

Protective Effect and Mechanism of Aspirin Eugenol Ester on Lipopolysaccharide-Induced Intestinal Barrier Injury

Intestinal inflammation is a complex and recurrent inflammatory disease. Pharmacological and pharmacodynamic experiments showed that aspirin eugenol ester (AEE) has good anti-inflammatory, antipyretic, and analgesic effects. However, the role of AEE in regulating intestinal inflammation has not been explored. This study aimed to investigate whether AEE could have a protective effect on LPS-induced intestinal inflammation and thus help to alleviate the damage to the intestinal barrier. This was assessed with an inflammation model in Caco-2 cells and in rats induced with LPS. The expression of inflammatory mediators, intestinal epithelial barrier-related proteins, and redox-related signals was analyzed using an enzyme-linked immunosorbent assay (ELISA), Western blotting, immunofluorescence staining, and RT-qPCR. Intestinal damage was assessed by histopathological examination. Changes in rat gut microbiota and their functions were detected by the gut microbial metagenome. AEE significantly reduced LPS-induced pro-inflammatory cytokine levels (p < 0.05) and oxidative stress levels in Caco-2 cells and rats. Compared with the LPS group, AEE could increase the relative expression of Occludin, Claudin-1, and zonula occludens-1 (ZO-1) and decrease the relative expression of kappa-B (NF-κB) and matrix metalloproteinase-9. AEE could significantly improve weight loss, diarrhea, reduced intestinal muscle thickness, and intestinal villi damage in rats. Metagenome results showed that AEE could regulate the homeostasis of the gut flora and alter the relative abundance of Firmicutes and Bacteroidetes. Flora enrichment analysis indicated that the regulation of gut flora with AEE may be related to the regulation of glucose metabolism and energy metabolism. AEE could have positive effects on intestinal inflammation-related diseases.

Network pharmacology and molecular docking reveal potential mechanism of esculetin in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of the colonic mucosa. Esculetin is a type of natural coumarin that has many pharmacological activities such as antioxidant, anticancer, anti-inflammatory, etc. A previous study showed that esculetin improved intestinal inflammation and reduced serum proinflammatory cytokines in UC. The present study aimed to utilize network pharmacology and molecular docking to explore the potential mechanism of esculetin against UC. The potential gene targets of esculetin were predicted through SwissTargetPrediction and Super-PRED web servers. UC-related genes were obtained from DisGeNet, OMIM, and GeneCards databases. The overlap between gene targets of esculetin and UC-related genes were identified as the potential targets of esculetin against UC. The interaction between these overlapping genes was analyzed by the STRING database and the core genes were identified by Cytoscape platform. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of the core genes were then performed. And the results of these analyses were further confirmed through molecular docking. A total of 50 overlapping genes were identified as the potential action targets of esculetin against UC. Among them, 10 genes (AKT1, STAT1, CCND1, SRC, PTGS2, EGFR, NFKB1, ESR1, MMP9, SERPINE1) were finally identified as the core genes. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis results showed that the top signaling pathway associated with the core genes of esculetin against UC was the prolactin (PRL) signaling pathway. Molecular docking results showed that esculetin has a strong binding affinity to the core genes, as well as PRL and prolactin receptor. This study suggests that esculetin may have a crucial impact on UC through the PRL signaling pathway and provides insights into the potential mechanism of esculetin in the treatment of UC, which may shed light on the mechanism and treatment of UC.

Exosomal miR-103a-3p from Crohn's Creeping Fat-Derived Adipose-Derived Stem Cells Contributes to Intestinal Fibrosis by Targeting TGFBR3 and Activating Fibroblasts

BACKGROUND AND AIMS

Mesenteric adipose tissue hypertrophy is a hallmark of Crohn's disease [CD], and creeping fat [CF] is unique to CD. Adipose-derived stem cells [ASCs] from inflammatory tissue exhibited altered biological functions. The role of ASCs isolated from CF in intestinal fibrosis and the potential mechanism remain unclear.

METHODS

ASCs were isolated from CF [CF-ASCs] and disease-unaffected mesenteric adipose tissue [Ctrl-ASCs] of patients with CD. A series of in vitro and in vivo experiments were conducted to study the effects of exosomes from CF-ASCs [CF-Exos] on intestinal fibrosis and fibroblast activation. A micro-RNA microarray analysis was performed. Western blot, luciferase assay and immunofluorescence were performed to further detect the underlying mechanisms.

RESULTS

The results indicated that CF-Exos promoted intestinal fibrosis by activating fibroblasts in a dose-dependent manner. They continuously promoted progression of intestinal fibrosis even after dextran sulphate sodium withdrawal. Further analysis showed that exosomal miR-103a-3p was enriched in CF-Exos and participated in exosome-mediated fibroblast activation. TGFBR3 was identified as a target gene of miR-103a-3p. Mechanistically, CF-ASCs released exosomal miR-103a-3p and promoted fibroblast activation by targeting TGFBR3 and promoting Smad2/3 phosphorylation. We also found that the expression of miR-103a-3p in diseased intestine was positively associated with the degree of CF and fibrosis score.

CONCLUSION

Our findings show that exosomal miR-103a-3p from CF-ASCs promotes intestinal fibrosis by activating fibroblasts via TGFBR3 targeting, suggesting that CF-ASCs are potential therapeutic targets for intestinal fibrosis in CD.

The role of autoimmunity and autoinflammation in giant cell arteritis: A systematic literature review

Giant cell arteritis is the most common form of large vessel vasculitis and preferentially involves large and medium-sized arteries in patients over the age of 50. Aggressive wall inflammation, neoangiogenesis and consecutive remodeling processes are the hallmark of the disease. Though etiology is unknown, cellular and humoral immunopathological processes are well understood. Matrix metalloproteinase-9 mediated tissue infiltration occurs through lysis of basal membranes in adventitial vessels. CD4+ cells attain residency in immunoprotected niches, differentiate into vasculitogenic effector cells and enforce further leukotaxis. Signaling pathways involve the NOTCH1-Jagged1 pathway opening vessel infiltration, CD28 mediated T-cell overstimulation, lost PD-1/PD-L1 co-inhibition and JAK/STAT signaling in interferon dependent responses. From a humoral perspective, IL-6 represents a classical cytokine and potential Th-cell differentiator whereas interferon-γ (IFN- γ) has been shown to induce chemokine ligands. Current therapies involve glucocorticoids, tocilizumab and methotrexate application. However, new agents, most notably JAK/STAT inhibitors, PD-1 agonists and MMP-9 blocking substances, are being evaluated in ongoing clinical trials.

Identification of Novel Core Genes Involved in Malignant Transformation of Inflamed Colon Tissue Using a Computational Biology Approach and Verification in Murine Models

Inflammatory bowel disease (IBD) is a complex and multifactorial systemic disorder of the gastrointestinal tract and is strongly associated with the development of colorectal cancer. Despite extensive studies of IBD pathogenesis, the molecular mechanism of colitis-driven tumorigenesis is not yet fully understood. In the current animal-based study, we report a comprehensive bioinformatics analysis of multiple transcriptomics datasets from the colon tissue of mice with acute colitis and colitis-associated cancer (CAC). We performed intersection of differentially expressed genes (DEGs), their functional annotation, reconstruction, and topology analysis of gene association networks, which, when combined with the text mining approach, revealed that a set of key overexpressed genes involved in the regulation of colitis (C3, Tyrobp, Mmp3, Mmp9, Timp1) and CAC (Timp1, Adam8, Mmp7, Mmp13) occupied hub positions within explored colitis- and CAC-related regulomes. Further validation of obtained data in murine models of dextran sulfate sodium (DSS)-induced colitis and azoxymethane/DSS-stimulated CAC fully confirmed the association of revealed hub genes with inflammatory and malignant lesions of colon tissue and demonstrated that genes encoding matrix metalloproteinases (acute colitis: Mmp3, Mmp9; CAC: Mmp7, Mmp13) can be used as a novel prognostic signature for colorectal neoplasia in IBD. Finally, using publicly available transcriptomics data, translational bridge interconnecting of listed colitis/CAC-associated core genes with the pathogenesis of ulcerative colitis, Crohn's disease, and colorectal cancer in humans was identified. Taken together, a set of key genes playing a core function in colon inflammation and CAC was revealed, which can serve both as promising molecular markers and therapeutic targets to control IBD and IBD-associated colorectal neoplasia.

The role of intestinal immune cells and matrix metalloproteinases in inflammatory bowel disease

Inflammatory bowel disease (IBD) has become globally intractable. MMPs play a key role in many inflammatory diseases. However, little is known about the role of MMPs in IBD. In this study, IBD expression profiles were screened from public Gene Expression Omnibus datasets. Functional enrichment analysis revealed that IBD-related specific functions were associated with immune pathways. Five MMPS-related disease markers, namely MMP-9, CD160, PTGDS, SLC26A8, and TLR5, were selected by machine learning and the correlation between each marker and immune cells was evaluated. We then induced colitis in C57 mice using sodium dextran sulfate and validated model construction through HE staining of the mouse colon. WB and immunofluorescence experiments confirmed that the expression levels of MMP-9, PTGDS, SLC26A8, and CD160 in colitis were significantly increased, whereas that of TLR5 were decreased. Flow cytometry analysis revealed that MMPs regulate intestinal inflammation and immunity mainly through CD8 in colitis. Our findings reveal that MMPs play a crucial role in the pathogenesis of IBD and are related to the infiltration of immune cells, suggesting that MMPs may promote the development of IBD by activating immune infiltration and the immune response. This study provides insights for further studies on the occurrence and development of IBD.

Macrophages in intestinal fibrosis and regression

Intestinal macrophages are heterogenous cell populations with different developmental ontogeny and tissue anatomy. The concerted actions of intestinal macrophage subsets are critical to maintaining tissue homeostasis. However, the dysregulation of macrophages following tissue injury or chronic inflammation could also lead to intestinal fibrosis, with few treatment options in the clinic. In this review, we will characterize the features of intestinal macrophages in light of the latest advances in lineage tracing and single-cell sequencing technology. The roles of macrophages in distinct stages of intestinal fibrosis would be also elaborated. Finally, based on the reciprocal interaction between macrophages and intestinal fibrosis, we will propose the potential macrophage targeting anti-intestinal fibrosis therapies.

Ameliorative effect of two structurally divergent hydrazide derivatives against DSS-induced colitis by targeting Nrf2 and NF-κB signaling in mice

The environmental factors and genetic vulnerability trigger the inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn's disease. Furthermore, the oxidative stress and inflammatory cytokines have been implicated in the aggravation of the IBDs. The aim of the present study was to investigate the effect of N-(benzylidene)-2-((2-hydroxynaphthalen-1-yl)diazenyl)benzohydrazides (NCHDH and NTHDH) compounds against the DSS-induced colitis in mice. The colitis was induced by 5% dextran sulfate sodium (DSS) dissolved in normal saline for 5 days. The effect of the NCHDH and NTHDH on the behavioral, biochemical, histological, and immunohistological parameters was assessed. The NCHDH and NTHDH treatment improved the behavioral parameters such as food intake, disease activity index, and diarrhea score significantly compared to DSS control. The NCHDH and NTHDH treatments significantly increased the antioxidant enzymes, whereas oxidative stress markers were markedly reduced. Similarly, the NCHDH and NTHDH treatments significantly suppressed the activity of nitric oxide (NO), myeloperoxidase (MPO), and eosinophil peroxidase (EPO). The histological studies showed a significant reduction in inflammation, immune cell infiltration, and fibrosis in the NCHDH- and NTHDH-treated groups. The immunohistochemical results demonstrated that NCHDH and NTHDH treatments markedly increase the expression level of Nrf2, HO-1 (hemeoxygenase-1), TRX (thioredoxin reductase), and IκB compared to the DSS-induced group. In the same way, the NCHDH and NTHDH significantly reduced the NF-κB and COX-2 (cyclooxygenase-2) expression levels. The NCHDH and NTHDH treatment significantly improved the symptoms associated with colitis via inducing antioxidants and attenuating oxidative stress markers.

How to place the duality of specific MMP-9 inhibition for treatment of inflammatory bowel diseases into clinical opportunities?

Crohn’s disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBD) with the involvement of immune cells and molecules, including cytokines, chemokines and proteases. A previous extensive review about the molecular biology of matrix metalloproteases (MMPs) and tissue inhibitors of metalloproteases (TIMPs), related to intestinal barrier destruction and restoration functions in IBD, is here complemented with the literature from the last five years. We also compare IBD as a prototypic mucosal inflammation of an epithelial barrier against microorganisms with inflammatory retinopathy as a disease with a barrier dysfunction at the level of blood vessels. Multiple reasons are at the basis of halting clinical trials with monoclonal antibodies against MMP-9 for IBD treatment. These include (i) the absence of a causative role of MMP-9 in the pathology in animal models of IBD, (ii) the fact that endotoxins, crossing the intestinal barrier, induce massive local release of both neutrophil collagenase (MMP-8) and gelatinase B (MMP-9), (iii) insufficient recognition that MMPs modify the activities of cytokines, chemokines and their receptors, (iv) ignorance that MMPs exist as mixtures of proteoforms with different posttranslational modifications and with different specific activities and (v) the fact that MMPs and TIMPs act in an interactive network, possibly having also beneficial effects on IBD evolution. Nevertheless, inhibition of MMPs may be a useful therapeutic approach during specific IBD disease phases or in specific sub-phenotypes. This temporary “window of opportunity” for MMP-9 inhibition may be complemented by a locoregional one, provided that the pharmacological agents are targeted in time to affected tissues, as is achieved in ophthalmological inflammation. Thus, in order to discover spatial and temporal windows of opportunity for MMP inhibition as treatment of IBD, more preclinical work including well controlled animal studies will be further needed. In this respect, MMP-9/NGAL complex analysis in various body compartments is helpful for better stratification of IBD patients who may benefit from anti-MMP-9.

Characterization of Maladaptive Processes in Acute, Chronic and Remission Phases of Experimental Colitis in C57BL/6 Mice

Inflammatory bowel disease (IBD) is a chronic recurrent inflammatory disease with unknown etiology. Dextran sulfate sodium (DSS) induced colitis is a widely used mouse model in IBD research. DSS colitis involves activation of the submucosal immune system and can be used to study IBD-like disease characteristics in acute, chronic, remission and transition phases. Insight into colon inflammatory parameters is needed to understand potentially irreversible adaptations to the chronification of colitis, determining the baseline and impact of further inflammatory episodes. We performed analyses of non-invasive and invasive colitis parameters in acute, chronic and remission phases of the DSS colitis in C57BL/6 mice. Non-invasive colitis parameters poorly reflected inflammatory aspects of colitis in chronic remission phase. We found invasive inflammatory parameters, positively linked to repeated DSS-episodes, such as specific colon weight, inflamed colon area, spleen weight, absolute cell numbers of CD4+ and CD8+ T cells as well as B cells, blood IFN-γ level, colonic chemokines BLC and MDC as well as the prevalence of Turicibacter species in feces. Moreover, microbial Lactobacillus species decreased with chronification of disease. Our data point out indicative parameters of recurrent gut inflammation in context of DSS colitis.

MMP9 expression in intestinal fistula from patients with fistulizing CD and from human xenograft mouse model

Fistula treatment represents a major unmet medical need in the therapy of Crohn's disease (CD). Current medical therapies, such as anti-TNF antibody treatments, are often insufficient and do not achieve permanent fistula closure. Previously published data point toward a critical role for metalloproteinase-9 (MMP-9)/gelatinase B in fistula pathogenesis. The aim of this project was to investigate in detail MMP-9 expression in different fistula types and to confirm that MMP-9 is a potential target for fistula therapy in CD patients.Immunohistochemistry for total and active MMP-9, Cytokeratin 8 (CK-8) and co-staining of active MMP-9/CK-8 was performed in specimen derived from perianal fistulas, entero-enteric fistulas and fistulas from patients not responding to anti-TNF therapy. In addition, fistulas from the xenograft mouse model (anti-TNF treated or untreated) were analyzed.Total and active MMP-9 protein was detectable in cells lining the tracts of perianal and entero-enteric fistulas. Of note, total and active MMP-9 was also expressed in fistulas of CD patients non-responding to anti-TNF treatment. Interestingly, we detected considerable co-staining of active MMP-9 and CK-8 in particular in cells lining the fistula tract and in transitional cells around the fistulas. Furthermore, total and active MMP-9 are detectable in both anti-TNF treated and untreated xenograft fistulas.Taken together, our data suggest that MMP-9 is involved in fistula pathogenesis in CD patients, in fistulas of different origins and particularly in patients non-responding to anti-TNF therapy. Our xenograft fistula model is suitable for in vivo studies investigating a possible therapeutic role for MMP-9 targeting as fistula therapy.

Beyond Immunity: Underappreciated Functions of Intestinal Macrophages

The gastrointestinal tract hosts the largest compartment of macrophages in the body, where they serve as mediators of host defense and immunity. Seeded in the complex tissue-environment of the gut, an array of both hematopoietic and non-hematopoietic cells forms their immediate neighborhood. Emerging data demonstrate that the functional diversity of intestinal macrophages reaches beyond classical immunity and includes underappreciated non-immune functions. In this review, we discuss recent advances in research on intestinal macrophage heterogeneity, with a particular focus on how non-immune functions of macrophages impact tissue homeostasis and function. We delve into the strategic localization of distinct gut macrophage populations, describe the potential factors that regulate their identity and functional heterogeneity within these locations, and provide open questions that we hope will inspire research dedicated to elucidating a holistic view on macrophage-tissue cell interactions in the body's largest mucosal organ.

Intracolic ultrasound molecular imaging: a novel method for assessing colonic tumor necrosis factor-α expression in inflammatory bowel disease

BACKGROUND

While anti-tumor necrosis factor alpha (TNF-α) therapy has been proven effective in inflammatory bowel disease (IBD), approximately 40% of patients lose the response. Transmembrane TNF-α (mTNF-α) expression in the intestinal mucosa is correlated with therapeutic efficacy, and quantification of mTNF-α expression is significant for predicting response. However, conventional intravenous application of microbubbles is unable to assess mTNF-α expression in intestinal mucosa. Herein, we proposed intracolic ultrasound molecular imaging with TNF-α-targeted microbubbles (MBTNF-α) to quantitatively detect mTNF-α expression in the intestinal mucosa.

METHODS

MBTNF-α was synthesized via a biotin-streptavidin bridging method. TNF-α-targeted ultrasound imaging was performed by intracolic application of MBTNF-α to detect mTNF-α expression in surgical specimens from a murine model and patients with IBD. Linear regression analyses were performed to confirm the accuracy of quantitative targeted ultrasound imaging.

RESULTS

On quantitative TNF-α-targeted ultrasound images, a greater signal intensity was observed in the mouse colons with colitis ([1.96 ± 0.45] × 106 a.u.) compared to that of the controls ([0.56 ± 0.21] × 106 a.u., P < 0.001). Targeted US signal intensities and inflammatory lesions were topographically coupled in mouse colons. Linear regression analyses in specimens of mice and patients demonstrated significant correlations between the targeted ultrasound signal intensity and mTNF-α expression (both P < 0.001). Furthermore, TNF-α-targeted ultrasound imaging qualitatively distinguished the varying inflammatory severity in intestinal specimens from IBD patients.

CONCLUSION

Intracolic ultrasound molecular imaging with MBTNF-α enables quantitative assessment of mTNF-α expression. It may be a potential tool for facilitating the implementation of personalized medicine in IBD.

Extracellular Metalloproteinases in the Plasticity of Excitatory and Inhibitory Synapses

Long-term synaptic plasticity is shaped by the controlled reorganization of the synaptic proteome. A key component of this process is local proteolysis performed by the family of extracellular matrix metalloproteinases (MMPs). In recent years, considerable progress was achieved in identifying extracellular proteases involved in neuroplasticity phenomena and their protein substrates. Perisynaptic metalloproteinases regulate plastic changes at synapses through the processing of extracellular and membrane proteins. MMP9 was found to play a crucial role in excitatory synapses by controlling the NMDA-dependent LTP component. In addition, MMP3 regulates the L-type calcium channel-dependent form of LTP as well as the plasticity of neuronal excitability. Both MMP9 and MMP3 were implicated in memory and learning. Moreover, altered expression or mutations of different MMPs are associated with learning deficits and psychiatric disorders, including schizophrenia, addiction, or stress response. Contrary to excitatory drive, the investigation into the role of extracellular proteolysis in inhibitory synapses is only just beginning. Herein, we review the principal mechanisms of MMP involvement in the plasticity of excitatory transmission and the recently discovered role of proteolysis in inhibitory synapses. We discuss how different matrix metalloproteinases shape dynamics and turnover of synaptic adhesome and signal transduction pathways in neurons. Finally, we discuss future challenges in exploring synapse- and plasticity-specific functions of different metalloproteinases.

Serological Biomarkers of Tissue Turnover Identify Responders to Anti-TNF Therapy in Crohn's Disease: A Pilot Study

INTRODUCTION

Anti-tumor necrosis factor (TNF) therapy is effective in inducing remission in Crohn's disease in 60% of patients. No serological biomarkers are available, which can predict response to anti-TNF. We aimed to investigate serological markers of collagen turnover reflecting tissue inflammation as predictors of response to anti-TNF.

METHODS

In 2 retrospective observational cohorts, markers for matrix metalloproteinase-degraded type III and IV collagens (C3M and C4M, respectively) and for formation of type III and IV collagens (PRO-C3 and PRO-C4, respectively) were measured in serum and compared with standard C-reactive protein in patients with active Crohn's disease who started infliximab (IFX, n = 21) or adalimumab (ADA, n = 21). Disease activity was classified by the Harvey-Bradshaw index (active disease ≥5); response was defined as clinical remission.

RESULTS

Seventeen patients (81%) treated with IFX were in remission at week 14; 15 patients (71%) treated with ADA were in remission at week 8. Serum C4M at baseline was increased in nonresponders compared with responders (IFX: 35.0 ± 2.4 vs 23.2 ± 2.6, P = 0.04, ADA: 53.0 ± 3.2 vs 34.1 ± 2.8, P = 0.006). C4M levels at baseline predicted response in both cohorts (IFX: odds ratio 39 [95% confidence interval, 2.4-523.9] P = 0.02, cutoff 35.2 nmol/L; ADA: odds ratio 26 [95% confidence interval, 1.8-332.5], P = 0.01, cutoff 46.9 nmol/L). C-reactive protein was not able to predict response to anti-TNF.

DISCUSSION

Response to anti-TNF therapy within the first 14 weeks of treatment can be predicted based on baseline levels of basement membrane marker C4M. This marker could be used as biomarker for response to anti-TNF and could aid in early therapy decision making. Validation in larger well-defined cohorts is needed.

Skin damage caused by scale loss modifies the intestine of chronically stressed gilthead sea bream (Sparus aurata, L.)

The present study was designed to test if the damage caused by scale loss provokes a change in other innate immune barriers such as the intestine and how chronic stress affects this response. Sea bream (Sparus aurata) were kept in tanks at low density (16 kg m^-3, LD) or exposed to a chronic high density (45 kg m^-3, HD) stress for 4 weeks. Scales were then removed (approximately 50%) from the left flank in the LD and HD fish. Intestine samples (n = 8/group) were examined before and at 12 h, 3 days and 7 days after scale removal. Changes in the morphology of the intestine revealed that chronic stress and scale loss was associated with intestinal inflammation. Specifically, enterocyte height and the width of the lamina propria, submucosa and muscle layer were significantly increased (p < 0.05) 3 days after skin damage in fish under chronic stress (HD) compared to other treatments (LDWgut3d or HDgut0h). This was associated with a significant up-regulation (p < 0.05) in the intestine of gene transcripts for cell proliferation (pcna) and anti-inflammatory cytokine tgfβ1 and down-regulation of gene transcripts for the pro-inflammatory cytokines tnf-α and il1β (p < 0.05) in HD and LD fish 3 days after scale removal compared to the undamaged control (LDgut0h). Furthermore, a significant up-regulation of kit, a marker of mast cells, in the intestine of HDWgut3d and LDWgut3d fish suggests they may mediate the crosstalk between immune barriers. Skin damage induced an increase in cortisol levels in the anterior intestine in HDWgut12 h fish and significant (p < 0.05) down-regulation of mr expression, irrespective of stress. These results suggest glucocorticoid levels and signalling in the intestine of fish are modified by superficial cutaneous wounds and it likely modulates intestine inflammation.

The Charming World of the Extracellular Matrix: A Dynamic and Protective Network of the Intestinal Wall

The intestinal extracellular matrix (ECM) represents a complex network of proteins that not only forms a support structure for resident cells but also interacts closely with them by modulating their phenotypes and functions. More than 300 molecules have been identified, each of them with unique biochemical properties and exclusive biological functions. ECM components not only provide a scaffold for the tissue but also afford tensile strength and limit overstretch of the organ. The ECM holds water, ensures suitable hydration of the tissue, and participates in a selective barrier to the external environment. ECM-to-cells interaction is crucial for morphogenesis and cell differentiation, proliferation, and apoptosis. The ECM is a dynamic and multifunctional structure. The ECM is constantly renewed and remodeled by coordinated action among ECM-producing cells, degrading enzymes, and their specific inhibitors. During this process, several growth factors are released in the ECM, and they, in turn, modulate the deposition of new ECM. In this review, we describe the main components and functions of intestinal ECM and we discuss their role in maintaining the structure and function of the intestinal barrier. Achieving complete knowledge of the ECM world is an important goal to understand the mechanisms leading to the onset and the progression of several intestinal diseases related to alterations in ECM remodeling.

MMP-9 Knockdown Inhibits Oral Squamous Cell Carcinoma Lymph Node Metastasis in the Nude Mouse Tongue-Xenografted Model through the RhoC/Src Pathway

Oral squamous cell carcinoma (OSCC) is one of the most common types of cancers in developing countries. A major contributor to the high mortality rate of OSCC is the tendency of oral cancer cells to metastasize to lymph nodes around the head and neck during the early stages of cancer development. Matrix metalloproteinase 9 (MMP-9), an endopeptidase, can degrade the extracellular matrix and basement membrane and plays a key role in tumor invasion and metastasis. In vitro, cell migration ability was conducted by scratching assays. We also investigated the interaction abilities between OSCC cells and vascular endothelial cells (ECs) by an adhesion assay and transendothelial migration assay. And we established a BALB/c nude mouse tongue-xenografted metastasis model to investigate the role of MMP-9 and explore its potential underlying mechanism in OSCC growth, lymph node metastasis, and angiogenesis in vivo. The results showed that knockdown of MMP-9 could significantly suppress OSCC cell migration, proliferation, interactions between endothelial cells, xenografted tumor growth, and angiogenesis and simultaneously markedly inhibited OSCC cell metastasis to mouse lymphonodi cervicales superficiales, axillary lymph nodes, and even distant inguinal lymph nodes. Mechanistic studies revealed that knockdown of MMP-9 also led to a decreased expression of RhoC, Src, and F-actin by RT-PCR, western blotting, and immunohistochemistry. And the bioinformatic analysis showed that MMP-9, RhoC, and Src mRNA expression was positively and linearly correlated in OSCC on TCGA database. Together, our findings indicated that MMP-9 plays a very important role in OSCC growth, migration, angiogenesis, and lymph node metastasis, and its potential mechanism may be mediated by RhoC and Src gene expression.

Digestive Inflammation: Role of Proteolytic Dysregulation

Dysregulation of the proteolytic balance is often associated with diseases. Serine proteases and matrix metalloproteases are involved in a multitude of biological processes and notably in the inflammatory response. Within the framework of digestive inflammation, several studies have stressed the role of serine proteases and matrix metalloproteases (MMPs) as key actors in its pathogenesis and pointed to the unbalance between these proteases and their respective inhibitors. Substantial efforts have been made in developing new inhibitors, some of which have reached clinical trial phases, notwithstanding that unwanted side effects remain a major issue. However, studies on the proteolytic imbalance and inhibitors conception are directed toward host serine/MMPs proteases revealing a hitherto overlooked factor, the potential contribution of their bacterial counterpart. In this review, we highlight the role of proteolytic imbalance in human digestive inflammation focusing on serine proteases and MMPs and their respective inhibitors considering both host and bacterial origin.

The Role of Extracellular Matrix Components in Inflammatory Bowel Diseases

The remodeling of extracellular matrix (ECM) within the intestine tissues, which simultaneously involves an increased degradation of ECM components and excessive intestinal fibrosis, is a defining trait of the progression of inflammatory bowel diseases (IBDs), which include ulcerative colitis (UC) and Crohn's disease (CD). The increased activity of proteases, especially matrix metalloproteinases (MMPs), leads to excessive degradation of the extracellular matrix and the release of protein and glycoprotein fragments, previously joined with the extracellular matrix, into the circulation. MMPs participate in regulating the functions of the epithelial barrier, the immunological response, and the process of wound healing or intestinal fibrosis. At a later stage of fibrosis during IBD, excessive formation and deposition of the matrix is observed. To assess changes in the extracellular matrix, quantitative measurement of the concentration in the blood of markers dependent on the activity of proteases, involved in the breakdown of extracellular matrix proteins as well as markers indicating the formation of a new ECM, has recently been proposed. This paper describes attempts to use the quantification of ECM components as markers to predict intestinal fibrosis and evaluate the healing process of the gut. The markers which reflect increased ECM degradation, together with the ones which show the process of creating a new matrix during IBD, allow the attainment of important information regarding the changes in the intestinal tissue, epithelial integrity and extracellular matrix remodeling. This paper contains evidence confirming that ECM remodeling is an integral part of directional cell signaling in the progression of IBD, and not only a basis for the ongoing processes.

Cadmium exacerbates dextran sulfate sodium-induced chronic colitis and impairs intestinal barrier

The potential health risk of environmental pollutant, cadmium, has become a public concern due to its widespread existence and long biological half-life. High-dose cadmium can induce various adverse outcomes, however, the chronic biological influences of cadmium at an environmental dosage and its mechanism remain largely unclear. Here, we investigated the effect of long-term exposure of cadmium at the environmental-relevant concentration on intestinal function. A chronic colitis mouse model was established through multiple cycles of dextran sulfate sodium (DSS) challenge and recovery. 200 nM cadmium in drinking water intensified colonic inflammation induced by DSS (histological score, DSS vs. DSS + Cd: 7.4 ± 1.21 vs. 10.67 ± 0.67, P < 0.05), including fecal occult bleeding and fecal consistency loss. Multiple inflammatory cytokines were significantly up-regulated by cadmium both in colon and plasma (P < 0.05). In addition, intestinal integrity was compromised by cadmium. Goblet cells were markedly reduced (ctrl vs. Cd: 48.33 ± 3.07 vs. 37.5 ± 2.14, P < 0.05) and plasma D-lactate (ctrl vs. Cd: 1.88 ± 0.20 vs. 2.80 ± 0.15, P < 0.01) and diamine oxidase (ctrl vs. Cd: 5.00 ± 0.87 vs. 11.21 ± 2.17, P < 0.05) were increased in cadmium-treated mice, indicating an elevated intestinal permeability. In vitro results showed that long-term exposure of cadmium down-regulated the expression and membrane localization of adherent and tight junction proteins in a time-dependent manner. In conclusion, long-term exposure of environmental dose of cadmium aggravated DSS-induced chronic colitis and disrupted intestinal barrier and impaired the adherent and tight junction proteins. These findings provide a better understanding about the health risk of cadmium in the environment.

Intestinal stenosis in Crohn's disease shows a generalized upregulation of genes involved in collagen metabolism and recognition that could serve as novel anti-fibrotic drug targets

BACKGROUND AND AIMS

Crohn's disease (CD) can be complicated by intestinal fibrosis. Pharmacological therapies against intestinal fibrosis are not available. The aim of this study was to determine whether pathways involved in collagen metabolism are upregulated in intestinal fibrosis, and to discuss which drugs might be suitable to inhibit excessive extracellular matrix formation targeting these pathways.

METHODS

Human fibrotic and non-fibrotic terminal ileum was obtained from patients with CD undergoing ileocecal resection due to stenosis. Genes involved in collagen metabolism were analyzed using a microfluidic low-density TaqMan array. A literature search was performed to find potential anti-fibrotic drugs that target proteins/enzymes involved in collagen synthesis, its degradation and its recognition.

RESULTS

mRNA expression of collagen type I (COL1A1, 0.76 ± 0.28 versus 37.82 ± 49.85, p = 0.02) and III (COL3A1, 2.01 ± 2.61 versus 68.65 ± 84.07, p = 0.02) was increased in fibrotic CD compared with non-fibrotic CD. mRNA expression of proteins involved in both intra- and extracellular post-translational modification of collagens (prolyl- and lysyl hydroxylases, lysyl oxidases, chaperones), collagen-degrading enzymes (MMPs and cathepsin-K), and collagen receptors were upregulated in the fibrosis-affected part. A literature search on the upregulated genes revealed several potential anti-fibrotic drugs.

CONCLUSION

Expression of genes involved in collagen metabolism in intestinal fibrosis affected terminal ileum of patients with CD reveals a plethora of drug targets. Inhibition of post-translational modification and altering collagen metabolism might attenuate fibrosis formation in the intestine in CD. Which compound has the highest potential depends on a combination anti-fibrotic efficacy and safety, especially since some of the enzymes play key roles in the physiology of collagen.

MMP-9 Processing of Intestinal Smooth Muscle-derived GDNF is Required for Neurotrophic Action on Enteric Neurons

The neurotrophin GDNF guides development of the enteric nervous system (ENS) in embryogenesis and directs survival and axon outgrowth in postnatal myenteric neurons in vitro. GDNF expression in intestinal smooth muscle cells is dynamic, with upregulation by inflammatory cytokines in vitro or intestinal inflammation in vivo, but the role of post-translational proteolytic cleavage is undefined. In a co-culture model of myenteric neurons, smooth muscle and glia, inhibition of serine or cysteine protease activity was ineffective against the >2-fold increase in axon density caused by TNFα. However, inhibitors of metalloproteinases (MMP) identified an essential role of MMP-9, and qPCR and western blotting showed that pro-inflammatory cytokines increased both mRNA and protein expression for MMP-9, in both cellular lysates and conditioned medium (CM). Inhibition of MMP-9 prevented the cytokine-induced increase in mature GDNF in CM or cellular lysates of co-cultures or cell lines of intestinal smooth muscle cells (ISMC) from adult rat colon. Western blotting showed parallel upregulation of mature GDNF and MMP-9 vs control in ISMC isolated on Day 2 of TNBS-induced colitis. Nonetheless, transfection of GDNF plasmid into HEK-293 cells as a carrier system, or directly into the co-culture model, conveyed a strong neurotrophic effect that was MMP-9 dependent. We conclude that MMP-9 activity is required for the neurotrophic effects of GDNF on myenteric neurons in vitro. However, the coordinated upregulation of GDNF and MMP-9 in intestinal smooth muscle by inflammatory cytokines provides a supportive, target cell-derived environment that limits inflammatory damage to the ENS.

Faecalibacterium prausnitzii produces butyrate to decrease c-Myc-related metabolism and Th17 differentiation by inhibiting histone deacetylase 3

Decreased levels of Faecalibacterium prausnitzii (F. prausnitzii), whose supernatant plays an anti-inflammatory effect, are frequently found in inflammatory bowel disease (IBD) patients. However, the anti-inflammatory products in F. prausnitzii supernatant and the mechanism have not been fully investigated. Here we found that F. prausnitzii and F. prausnitzii-derived butyrate were decreased in the intestines of IBD patients. Supplementation with F. prausnitzii supernatant and butyrate could ameliorate colitis in an animal model. Butyrate, but not other substances produced by F. prausnitzii, exerted an anti-inflammatory effect by inhibiting the differentiation of T helper 17 (Th17) cells. The mechanism underlying the anti-inflammatory effects of the butyrate produced by F. prausnitzii involved the enhancement of the acetylation-promoted degradation of c-Myc through histone deacetylase 3 (HDAC3) inhibition. In conclusion, F. prausnitzii produced butyrate to decrease Th17 differentiation and attenuate colitis through inhibiting HDAC3 and c-Myc-related metabolism in T cells. The use of F. prausnitzii may be an effective new approach to decrease the level of Th17 cells in the treatment of inflammatory diseases.

Inhibition of plasminogen activator inhibitor-1 attenuates against intestinal fibrosis in mice

Background/Aims

Intestinal fibrosis is a major complication of Crohn’s disease (CD). The profibrotic protein transforming growth factor-β (TGF-β) has been considered to be critical for the induction of the fibrotic program. TGF-β has the ability to induce not only the expression of extracellular matrix (ECM) including collagen, but also the production of plasminogen activator inhibitor-1 (PAI-1) that prevents enzymatic degradation of the ECM during the onset of fibrotic diseases. However, the significance of PAI-1 in the developing intestinal fibrosis has not been fully understood. In the present study, we examined the actual expression of PAI-1 in fibrotic legion of intestinal inflammation and its correlation with the abnormal ECM deposition.

Methods

Chronic intestinal inflammation was induced in BALB/c mice using 8 repeated intrarectal injections of 2,4,6-trinitrobenzene sulfonic acid (TNBS). TM5275, a PAI-1 inhibitor, was orally administered as a carboxymethyl cellulose suspension each day for 2 weeks after the sixth TNBS injection.

Results

Using a publicly available dataset (accession number, GSE75214) and TNBS-treated mice, we observed increases in PAI-1 transcripts at active fibrotic lesions in both patients with CD and mice with chronic intestinal inflammation. Oral administration of TM5275 immediately after the onset of intestinal fibrosis upregulated MMP-9 (matrix metalloproteinase 9) and decreased collagen accumulation, resulting in attenuation of the fibrogenesis in TNBS-treated mice.

Conclusions

PAI-1-mediated fibrinolytic system facilitates collagen degradation suppression. Hence, PAI-1 inhibitor could be applied as an anti-fibrotic drug in CD treatment.

Serum MMP-9: a novel biomarker for prediction of clinical relapse in patients with quiescent Crohn's disease, a post hoc analysis

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) is a novel marker of intestinal inflammation. The aim of this study was to assess if serum MMP-9 levels predict clinical flare in patients with quiescent Crohn's disease (CD).

METHODS

This study was a post hoc analysis of a prospective observational study in which quiescent CD patients were included and followed until clinical relapse or the end of a 2-year follow-up period. Serial C-reactive protein (CRP) and fecal calprotectin (FC) levels were measured, and the patients underwent repeated capsule endoscopies (CEs) every 6 months. Small bowel inflammation was quantified by Lewis score (LS) for CE. A baseline magnetic resonance enterography was also performed, and MaRIA score was calculated. Serum MMP-9 levels in baseline blood samples were quantified by ELISA.

RESULTS

Out of 58 eligible enrolled patients, 16 had a flare. Higher levels of baseline MMP-9 were found in patients who developed subsequent symptomatic flare compared with patients who did not [median 661 ng/ml, 25-75 interquartile range (IQR; 478.2-1441.3) versus 525.5 ng/ ml (339-662.7), respectively, p = 0.01]. Patients with serum MMP-9 levels of 945 ng/ ml or higher were at increased risk for relapse within 24 months [area under the curve (AUC) of 0.72 [95% confidence interval (CI): 0.56-0.88]; hazard ratio 8.1 (95% CI 3.0-21.9, p < 0.001)]. Serum MMP-9 concentrations showed weak and moderate correlation to baseline LS and FC, respectively (r = 0.31, p = 0.02; r = 0.46, p < 0.001). No correlation was found between serum MMP-9 to CRP and MaRIA score.

CONCLUSIONS

Serum MMP-9 may be a promising biomarker for prediction of clinical flare in CD patients with quiescent disease.

The Rebirth of Matrix Metalloproteinase Inhibitors: Moving Beyond the Dogma

The pursuit of matrix metalloproteinase (MMP) inhibitors began in earnest over three decades ago. Initial clinical trials were disappointing, resulting in a negative view of MMPs as therapeutic targets. As a better understanding of MMP biology and inhibitor pharmacokinetic properties emerged, it became clear that initial MMP inhibitor clinical trials were held prematurely. Further complicating matters were problematic conclusions drawn from animal model studies. The most recent generation of MMP inhibitors have desirable selectivities and improved pharmacokinetics, resulting in improved toxicity profiles. Application of selective MMP inhibitors led to the conclusion that MMP-2, MMP-9, MMP-13, and MT1-MMP are not involved in musculoskeletal syndrome, a common side effect observed with broad spectrum MMP inhibitors. Specific activities within a single MMP can now be inhibited. Better definition of the roles of MMPs in immunological responses and inflammation will help inform clinic trials, and multiple studies indicate that modulating MMP activity can improve immunotherapy. There is a U.S. Food and Drug Administration (FDA)-approved MMP inhibitor for periodontal disease, and several MMP inhibitors are in clinic trials, targeting a variety of maladies including gastric cancer, diabetic foot ulcers, and multiple sclerosis. It is clearly time to move on from the dogma of viewing MMP inhibition as intractable.

Screening for active constituents in Turkish galls against ulcerative colitis by mass spectrometry guided preparative chromatography strategy: in silico, in vitro and in vivo study

Turkish galls have been reported to exhibit remedial effects in ulcerative colitis (UC). However, the active constituents of Turkish galls for the treatment of UC remain unclear. The objective of this study was to screen for anti-inflammatory active constituents and clarify their associated molecular mechanisms. Therefore, systems pharmacology was developed to predict the relationship between constituents and the corresponding targets as well as pathways. In addition, mass spectrometry-guided preparative chromatography technique was used for preparing constituents to evaluate the anti-inflammatory activities and the therapeutic efficacy against UC. In silico, active constituents exhibited a remedial effect on UC possibly by regulating multiple pathways and attacking multiple targets, of which those involved mainly in the NF-κB pathway were selected for verification. In vitro, 5 categories of constituents were screened as active constituents by comparing the cytotoxicity and detecting the level of the pro-inflammatory factors of 9 category constituents. In vivo, dextran sulfate sodium (DSS)-induced UC was significantly ameliorated in active constituents-fed mice. The results indicated that the active fraction comprising methyl gallate, digallic acid, di-O-galloyl-β-d-glucose, and tri-O-galloyl-β-d-glucose primarily contributed to the treatment of UC. Moreover, active fraction could also inhibit the phosphorylation level of IKKβ, thus inhibiting the downstream NF-κB signaling pathway. The approach developed in this study not only clarifies the anti-inflammation effect of Turkish galls but also provides a beneficial reference for the discovery of the base material and functional mechanism of this herbal medicine.

Anti-Inflammatory Effect of IL-37-Producing T-Cell Population in DSS-Induced Chronic Inflammatory Bowel Disease in Mice

Inflammatory bowel disease (IBD) is a chronic inflammatory disease that is thought to arise in part from abnormal adaptive immune responses against intestinal microbiota. T lymphocytes play significant roles in triggering mucosal inflammation and/or maintaining gut immune homeostasis. It has been demonstrated that IL-37 expresses in a variety of cells and exerts a protective function involved in both innate immunity and adaptive immunity. In the present study, a population of IL-37-producing T-cells was detected in the spleen and mesenteric lymph nodes (MLNs) in IL-37+/+ mice after dextran sodium sulfate (DSS) induction. Adoptive transfer of the T-cells from the spleen of IL-37+/+ mice following DSS treatment partly recovered the body weight, improved the disease activity index (DAI) and macroscopic damage score, and attenuated the intestinal inflammation. In addition, colon shortening, an indirect marker of inflammation, was decreased, consistent with the decreased IFN-γ level and the increased IL-10 level in the colonic tissue. Collectively, our data uncovered a subset of T-lymphocytes expressing IL-37, which represents a potent regulation of immunity and serves as the protective role in chronic IBD.

Gelatinase B/matrix metalloproteinase-9 is a phase-specific effector molecule, independent from Fas, in experimental autoimmune encephalomyelitis

Gelatinase B/matrix metalloproteinase-9 (MMP-9) triggers multiple sclerosis (MS) and the animal model of experimental autoimmune encephalomyelitis (EAE) by the breakdown of the blood-brain barrier. Interestingly, MMP-9 is beneficial in systemic autoimmunity caused by Fas-deficiency. Fas-deficient (faslpr) and Fas-ligand-deficient mice are protected against EAE. We here investigated the interaction between Fas and MMP-9 in the setting of induction of EAE and compared short- and long-term effects. We provoked EAE with myelin oligodendrocyte glycoprotein (MOG) peptide and compared EAE development in four genotypes (wild-type (WT), single knockout mmp-9-/-, faslpr, and mmp-9-/-/faslpr) and monitored leukocytes, cytokines and chemokines as immunological parameters. As expected, faslpr mice were resistant against EAE induction, whereas MMP-9 single knockout mice were not. In the double mmp-9-/-/ faslpr mice the effects on disease scores pointed to independent rather than interrelated disease mechanisms. On a short term, after EAE induction leukocytes infiltrated into the brain and cytokine and chemokine levels were significantly higher in all the four genotypes studied, even in the faslpr and mmp-9-/-/faslpr, which did not develop clinical disease. The levels of MMP-9 but not of MMP-2 were increased in the brain and in the peripheral organs after EAE induction. After 40 days all the animals recovered and did not show signs of EAE. However, the absence of MMP-9 in the remission phase suggested a protective role of MMP-9 in the late phase of the disease, because single mmp-9-/- mice presented a delayed remission in comparison with WT animals suggesting a phase-dependent role of MMP-9 in the disease. Nevertheless, the levels of some cytokines and chemokines remained higher than in control animals even 100 days after EAE induction, attesting to a prolonged state of immune activation. We thus yielded new insights and useful markers to monitor this activated immune status. Furthermore, MMP-9 but not MMP-2 levels remained increased in the brains and, to a higher extend, in the spleens of the WT mice even during the remission phase, which is in line with the role of MMP-9 as a useful marker and a protective factor for EAE in the remission phase.

Comparisons of gut microbiota profiles in wild-type and gelatinase B/matrix metalloproteinase-9-deficient mice in acute DSS-induced colitis

Gut microbiota help to educate the immune system and a number of involved immune cells were recently characterized. However, specific molecular determinants in these processes are not known, and, reciprocally, little information exists about single host determinants that alter the microbiota. Gelatinase B/matrix metalloproteinase-9 (MMP-9), an innate immune regulator and effector, has been suggested as such a host determinant. In this study, acute colitis was induced in co-housed MMP-9^-/- mice (n = 10) and their wild-type (WT) littermates (n = 10) via oral administration of 3% dextran sodium sulfate (DSS) for 7 days followed by 2 days of regular drinking water. Control mice (10 WT and 10 MMP-9^-/-) received normal drinking water. Fecal samples were collected at time of sacrifice and immediately frozen at −80 °C. Microbiota analysis was performed using 16S rRNA amplicon sequencing on Illumina MiSeq and taxonomic annotation was performed using the Ribosomal Database Project as reference. Statistical analysis correcting for multiple testing was done using R. No significant differences in clinical or histopathological parameters were found between both genotypes with DSS-induced colitis. Observed microbial richness at genus level and microbiota composition were not significantly influenced by host genotype. In contrast, weight loss, disease activity index, cage, and phenotype did significantly influence the intestinal microbiota composition. After multivariate analysis, cage and phenotype were identified as the sole drivers of microbiota composition variability. In conclusion, changes in fecal microbiota composition were not significantly altered in MMP-9-deficient mice compared to wild-type littermates, but instead were mainly driven by DSS-induced colonic inflammation.

A protein that regulates aspects of the immune system has been proposed to influence gut microbial populations implicated in the inflammatory conditions known as colitis, but new evidence suggests the protein has no such effect. Ghislain Opdenakker and colleagues at the Rega Institute for Medical Research in Belgium examined the issue in mice with chemically induced colitis. The gut microbes of normal “wild-type” animals were compared with those in animals lacking the gene for the protein, “gelatinase B/matrix metalloproteinase-9”. The absence of the gene, and therefore of the protein it codes for, caused no significant alteration in the gut microbial population. The presence of colitis, however, did alter the gut microbial population relative to mice with no colitis. The results will assist work to understand the networks of cause and effect linking gut microbes and colitis.

A Phase 2, Randomized, Placebo-Controlled Study Evaluating Matrix Metalloproteinase-9 Inhibitor, Andecaliximab, in Patients With Moderately to Severely Active Crohn's Disease

BACKGROUND AND AIMS

Matrix metalloproteinase-9 [MMP9] is implicated in the pathogenesis of Crohn's disease and may serve as a potential biomarker. A phase 2 trial was conducted to examine the efficacy and safety of the anti-MMP9 antibody andecaliximab [GS-5745] in patients with moderately to severely active Crohn's disease.

METHODS

Patients were randomized 1:2:2:2 to receive subcutaneous injections of placebo weekly [QW], andecaliximab 150 mg every 2 weeks [Q2W], andecaliximab 150 mg QW, or andecaliximab 300 mg QW.The co-primary study efficacy endpoints were evaluation of a clinical response, defined as liquid or very soft stool frequency and abdominal pain composite [from Patient-Reported Outcome 2] score ≤ 8 at week 8, and an endoscopic response, defined as a ≥ 50% reduction from baseline in the Simple Endoscopic Score for Crohn's Disease, following 8 weeks of treatment.

RESULTS

A total of 187 participants were randomized to treatment; 53 participants were randomized to each andecaliximab treatment group and 28 participants were randomized to placebo. Proportions of patients receiving andecaliximab were not different from proportions of patients receiving placebo based on clinical and endoscopic response and Crohn's disease activity index-defined remission at week 8. Rates of adverse events were comparable among the andecaliximab and placebo groups.

CONCLUSIONS

Eight weeks of induction treatment with 150 mg andecaliximab Q2W, 150 mg andecaliximab QW, or 300 mg andecaliximab QW in patients with Crohn's disease did not induce a clinically meaningful symptomatic or endoscopic response. Andecaliximab was well tolerated.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT02405442.

Andecaliximab [Anti-matrix Metalloproteinase-9] Induction Therapy for Ulcerative Colitis: A Randomised, Double-Blind, Placebo-Controlled, Phase 2/3 Study in Patients With Moderate to Severe Disease

BACKGROUND AND AIMS

Matrix metalloproteinase-9 [MMP9] is implicated in the pathogenesis of ulcerative colitis [UC] via disruption of intestinal barrier integrity and function. A phase 2/3 combined trial was designed to examine the efficacy, safety, and pharmacokinetics of the anti-MMP9 antibody, andecaliximab [formerly GS-5745], in patients with moderately to severely active UC.

METHODS

Patients were randomised [1:1:1] to receive placebo, 150 mg andecaliximab every 2 weeks [Q2W], or 150 mg andecaliximab weekly [QW], via subcutaneous administration. The primary endpoint was endoscopy/bleeding/stool [EBS]-defined clinical remission [endoscopic subscore of 0 or 1, rectal bleeding subscore of 0, and at least a 1-point decrease from baseline in stool frequency to achieve a subscore of 0 or 1] at Week 8. The phase 2/3 trial met prespecified futility criteria and was terminated before completion. This study describes results from the 8-week induction phase.

RESULTS

Neither 150 mg andecaliximab Q2W or QW resulted in a significant increase vs placebo in the proportion of patients achieving EBS clinical remission at Week 8. Remission rates [95% confidence intervals] were 7.3% [2.0%-17.6%], 7.4% [2.1%-17.9%], and 1.8% [0.0%-9.6%] in the placebo, andecaliximab Q2W, and andecaliximab QW groups, respectively. Similarly, Mayo Clinic Score response, endoscopic response, and mucosal [histological] healing did not differ among groups. Rates of adverse events were comparable among andecaliximab and placebo.

CONCLUSIONS

Eight weeks of induction treatment with 150 mg andecaliximab in patients with UC did not induce clinical remission or response. Andecaliximab was well tolerated and pharmacokinetic properties were consistent with those previously reported.

Neutrophils and Activated Macrophages Control Mucosal Immunity by Proteolytic Cleavage of Antileukoproteinase

Antileukoproteinase or secretory leukocyte peptidase inhibitor is a small protein which protects the mucosal linings against excessive proteolysis, inflammation, and microbial infection. We discovered that gelatinase B or matrix metalloproteinase (MMP)-9, a secreted zinc-dependent endopeptidase typically found at sites of inflammation, destroys antileukoproteinase by cleavages within both of its two functional domains: the anti-microbial N-terminal and the anti-proteolytic C-terminal domains. Cleaved antileukoproteinase possessed a significantly lower ability to bind lipopolysaccharides (LPS) and a reduced capacity to inhibit neutrophil elastase (NE) activity. Whereas intact antileukoproteinase repressed proinflammatory transcript [prostaglandin-endoperoxide synthase 2 (PTGS2) and IL6] synthesis and protein secretion [e.g., of MMP-9] in human CD14⁺ blood monocytes stimulated with LPS, this effect was reduced or lost for cleaved antileukoproteinase. We demonstrated the in vivo presence of antileukoproteinase cleavage fragments in lower airway secretions of non-cystic fibrosis bronchiectasis patients with considerable levels of neutrophils and, hence, elastase and MMP-9 activity. As a comparison, other MMPs (MMP-2, MMP-7, and MMP-8) and serine proteases (NE, cathepsin G, and proteinase 3) were also able to cleave antileukoproteinase with similar or reduced efficiency. In conclusion, in specific mucosal pathologies, such as bronchiectasis, neutrophils, and macrophage subsets control local immune reactions by proteolytic regulation, here described as the balance between MMPs (in particular MMP-9), serine proteases and local tissue inhibitors.

The apparent competitive action of ECM proteases and cross-linking enzymes during fibrosis: Applications to drug discovery

Progressive loss of organ function in most organs is associated with fibrosis, a tissue state associated with abnormal matrix buildup. If highly progressive, the fibrotic process eventually leads to organ failure and death. Fibrosis is a basic connective tissue lesion defined by the increase in the amount of fibrillar extracellular matrix (ECM) components in a tissue or organ. In addition, intrinsic changes in important structural cells can induce the fibrotic response by regulating the differentiation, recruitment, proliferation and activation of extracellular matrix-producing myofibroblasts. ECM enzymes belonging to the family of matrix metalloproteinases (MMPs) and lysyl oxidases (LOXs) play a crucial role in ECM remodeling and regeneration. MMPs have a catalytic role in degradation of ECM, whereas LOX/LOXLs mediate ECM, especially collagen, cross-linking and stiffening. Importantly, enzymes from both families are elevated during the fibrotic response to tissue injury and its resolution. Yet, the apparent molecular competition or antagonistic activities of these enzyme families during the various stages of fibrosis is often overlooked. In this review, we discuss the diverse roles of MMPs and LOX/LOXL2 in chronic organ fibrosis. Finally, we review contemporary therapeutic strategies for fibrosis treatment, based on neutralization of MMP and LOX activity, as well as the development of novel drug delivery approaches.

Immunomodulation as Rescue for Chronic Atonic Skin Wounds

Chronic skin wounds, caused by arterial or venous insufficiency or by physical pressure, constitute an increasing medical problem as populations age. Whereas typical wounds are characterized by local inflammation that participates in the healing process, atonic wounds lack inflammatory markers, such as neutrophil infiltration, and generally do not heal. Recently, prominent roles in the immunopathology of chronic wounds were attributed to dysregulations in specific cytokines, chemokines, matrix metalloproteinases (MMPs), and their substrates. Together with the complement system, these molecular players provide necessary defense against infections, initiate angiogenesis, and prepare tissue reconstitution. Here, we review the current state of the field and include the concept that, aside from surgery and stem cell therapy, healing may be enhanced by immunomodulating agents.