Epithelial Cell-Derived a Disintegrin and Metalloproteinase-17 Confers Resistance to Colonic Inflammation Through EGFR Activation

Breaking Down Barriers: Epithelial Contributors to Monogenic IBD Pathogenesis

Monogenic causes of inflammatory bowel diseases (IBD) are increasingly being discovered. To date, much attention has been placed in those resulting from inborn errors of immunity. Therapeutic efforts have been largely focused on offering personalized immune modulation or curative bone marrow transplant for patients with IBD and underlying immune disorders. To date, less emphasis has been placed on monogenic causes of IBD that pertain to impairment of the intestinal epithelial barrier. Here, we provide a comprehensive review of monogenic causes of IBD that result in impaired intestinal epithelial barrier that are categorized into 6 important functions: (1) epithelial cell organization, (2) epithelial cell intrinsic functions, (3) epithelial cell apoptosis and necroptosis, (4) complement activation, (5) epithelial cell signaling, and (6) control of RNA degradation products. We illustrate how impairment of any of these categories can result in IBD. This work reviews the current understanding of the genes involved in maintaining the intestinal barrier, the inheritance patterns that result in dysfunction, features of IBD resulting from these disorders, and pertinent translational work in this field.

Understanding very early onset inflammatory bowel disease (VEOIBD) in relation to inborn errors of immunity

Inflammatory bowel diseases (IBD) are multifactorial diseases which are caused by the combination of genetic predisposition, exposure factors (environmental and dietary), immune status, and dysbiosis. IBD is a disease which presents at any age, ranging from newborns to the elderly. The youngest of the pediatric IBD population have a more unique presentation and clinical course and may have a different etiology. Very early onset IBD (VEOIBD) patients, designated as those diagnosed prior the age of 6, have distinct features which are more frequent in this patient population including increased incidence of monogenetic causes for IBD (0%-33% depending on the study). This proportion is increased in the youngest subsets, which is diagnosed prior to the age of 2. To date, there are approximately 80 monogenic causes of VEOIBD that have been identified and published. Many of these monogenic causes are inborn errors of immunity yet the majority of VEOIBD patients do not have an identifiable genetic cause for their disease. In this review, we will focus on the clinical presentation, evaluation, and monogenic categories which have been associated with VEOIBD including (1) Epithelial cell defects (2) Adaptive immune defects, (3) Innate Immune/Bacterial Clearance and Recognition defects, and (4) Hyperinflammatory and autoinflammatory disorders. We will highlight differential diagnosis of VEOIBD presentations, as well as evaluation and treatment, which will be helpful for those who study and care for VEOIBD patients outside of the pediatric gastroenterology field. This is a fast-moving field of research which has grown significantly based on knowledge that we gain from our patients. These scientific findings have identified novel mucosal biology pathways and will continue to inform our understanding of gastrointestinal biology.

Exploration of molecular mechanism of Huanglian-Muxiang-Roudoukou formula in treating ulcerative colitis based on gene expression omnibus chip data mining combined with network pharmacology and molecular docking

BACKGROUND

Huanglian-Muxiang-Roudoukou (HMR) formula was recorded in the book of "Pediatric Medicine Prescription". It can improve the clinical symptoms of ulcerative colitis (UC). Using network pharmacology and other methods to study its biological mechanism is helpful to better explore the resources of traditional Chinese medicine and promote the modern development and application of traditional Chinese medicine in the prevention and treatment of UC.

AIM

To explore the potential molecular mechanism of HMR in the treatment of UC based on gene expression omnibus (GEO) chip data mining, network pharmacology, and molecular docking technology.

METHODS

The GEO database was used to obtain UC gene expression data. Then, differentially expressed genes were identified using R software. The active components of Myristicae Semen (Roudoukou), Aucklandiae Radix (Muxiang), and Coptidis Rhizoma (Huanglian) were searched by using the traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) database, and the corresponding targets were identified. The intersections of HMR and ulcerative colitis disease targets were obtained. The "drug-active ingredients-disease-target" network and protein-protein interaction (PPI) network were constructed to screen out the core components and targets using Cytoscape 3.9.1 software. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed for the intersection targets by Metascapes database. Molecular docking between main active components and core targets was performed using AutoDock vina software.

RESULTS

A total of 967 differential genes were identified, and there were 29 active components and 163 active targets in UC. There were 24 active components in the "drug-active ingredients-disease-target" network, including quercetin, stigmasterol, berberine, beta-sitosterol, palmatine, and so on. There were 26 proteins in the PPI network, including interleukin-1β (IL-1β), interleukin-6 (IL-6), C-C motif chemokine 2 (CCL2), tumor necrosis factor (TNF), matrix metallopeptidase 9 (MMP9), and so on. GO enrichment analysis demonstrated that the intersection targets were mainly concentrated in biological processes such as lipopolysaccharide response, in cellular components such as external side of plasma membrane, and in molecular functions such as cytokine activity. KEGG analysis demonstrated that the intersection targets mainly involved the TNF signal pathway, nuclear factor kappa-B (NF-κB) pathway, Toll-like receptor (TLR) signal pathway, and so on. The results of molecular docking showed that the top five main active components had strong binding ability with the core targets IL-1β, IL-6, CCL2, TNF, and MMP9.

CONCLUSION

HMR may act on the expression of IL-1β, IL-6, CCL2, and other proteins through quercetin, stigmasterol, berberine, and other active components, regulate the TNF signaling pathway, and play a role in the treatment of UC via many mechanisms such as anti-inflammatory and intestinal immunity regulation.

Investigating the Crime Scene-Molecular Signatures in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) are without cure and troublesome to manage because of the considerable diversity between patients and the lack of reliable biomarkers. Several studies have demonstrated that diet, gut microbiota, genetics and other patient factors are essential for disease occurrence and progression. Understanding the link between these factors is crucial for identifying molecular signatures that identify biomarkers to advance the management of IBD. Recent technological breakthroughs and data integration have fuelled the intensity of this research. This research demonstrates that the effect of diet depends on patient factors and gut microbial activity. It also identifies a range of potential biomarkers for IBD management, including mucosa-derived cytokines, gasdermins and neutrophil extracellular traps, all of which need further evaluation before clinical translation. This review provides an update on cutting-edge research in IBD that aims to improve disease management and patient quality of life.

Neutrophil-Epithelial Crosstalk During Intestinal Inflammation

Neutrophils are the most abundant leukocyte population in the human circulatory system and are rapidly recruited to sites of inflammation. Neutrophils play a multifaceted role in intestinal inflammation, as they contribute to the elimination of invading pathogens. Recently, their role in epithelial restitution has been widely recognized; however, they are also associated with bystander tissue damage. The intestinal epithelium provides a physical barrier to prevent direct contact of luminal contents with subepithelial tissues, which is extremely important for the maintenance of intestinal homeostasis. Numerous studies have demonstrated that transepithelial migration of neutrophils is closely related to disease symptoms and disruption of crypt architecture in inflammatory bowel disease and experimental colitis. There has been growing interest in how neutrophils interact with the epithelium under inflammatory conditions. Most studies focus on the effects of neutrophils on intestinal epithelial cells; however, the effects of intestinal epithelial cells on neutrophils during intestinal inflammation need to be well-established. Based on these data, we have summarized recent articles on the role of neutrophil-epithelial interactions in intestinal inflammation, particularly highlighting the epithelium-derived molecular regulators that mediate neutrophil recruitment, transepithelial migration, and detachment from the epithelium, as well as the functional consequences of their crosstalk. A better understanding of these molecular events may help develop novel therapeutic targets for mitigating the deleterious effects of neutrophils in inflammatory bowel disease.

Clostridium butyricum, a butyrate-producing potential probiotic, alleviates experimental colitis through epidermal growth factor receptor activation

Inflammatory bowel disease (IBD) is an idiopathic inflammatory bowel disease. Modulation of gut microbiota with dietary and nutritional targets is a feasible strategy for the prevention and treatment of IBD. In this study, we focused on Clostridium butyricum Prazmowski (CB), a butyrate-producing potential probiotic. We found that CB feeding decreased the disease activity index, colon inflammation/injury score and cell apoptosis in an experimental colitis mouse model, as well as elevated the level of SCFAs in cecal feces. CB could also balance the inflammatory cytokines, protect tight junctions, and increase the number of goblet cells and MUC2 production in mice, accompanied by EGFR signaling activation triggered by heparin-binding epidermal growth factor (HB-EGF) and amphiregulin (AREG). From the perspective of mechanism, the CB supernatant (CBS) stimulated EGFR activation in colon epithelial cell lines in concentration-dependent and time-dependent manners. CBS reduced the damage of tight junctions induced by H₂O₂, and inhibition of EGFR could suppress the protective effect of CBS. In conclusion, CB could protect the gut barrier and alleviate experimental colitis through the transactivation of EGFR signaling in intestinal epithelial cells induced by ligands (HB-EGF and AREG). This study identified the potential efficacy of CB as a preventive strategy for IBD and showed the broad prospect of CB as a food supplement.

Inflammatory activation of surface molecule shedding by upregulation of the pseudoprotease iRhom2 in colon epithelial cells

The metalloproteinase ADAM17 contributes to inflammatory and proliferative responses by shedding of cell-surface molecules. By this ADAM17 is implicated in inflammation, regeneration, and permeability regulation of epithelial cells in the colon. ADAM17 maturation and surface expression requires the adapter proteins iRhom1 or iRhom2. Here we report that expression of iRhom2 but not iRhom1 is upregulated in intestinal tissue of mice with acute colitis. Our analysis of public databases indicates elevated iRhom2 expression in mucosal tissue and epithelial cells from patients with inflammatory bowel disease (IBD). Consistently, expression of iRhom2 but not iRhom1 is upregulated in colon or intestinal epithelial cell lines after co-stimulation with tumor necrosis factor (TNF) and interferon gamma (IFNgamma). This upregulation can be reduced by inhibition of Janus kinases or transcription factors NF-kappaB or AP-1. Upregulation of iRhom2 can be mimicked by iRhom2 overexpression and is associated with enhanced maturation and surface expression of ADAM17 which then results in increased cleavage of transforming growth factor (TGF) alpha and junctional adhesion molecule (JAM)-A. Finally, the induction of these responses is suppressed by inhibition of iRhom2 transcription. Thus, inflammatory induction of iRhom2 may contribute to upregulated ADAM17-dependent mediator and adhesion molecule release in IBD. The development of iRhom2-dependent inhibitors may allow selective targeting of inflammatory ADAM17 activities.

High carbohydrate diet induced endoplasmic reticulum stress and oxidative stress, promoted inflammation and apoptosis, impaired intestinal barrier of juvenile largemouth bass (Micropterus salmoides)

This study assessed the effects of feed carbohydrate content on intestinal physical barrier and immunity in juvenile largemouth bass (Micropterus salmoides). Triplicate groups of juvenile fish (4.1 ± 0.2 g) were fed low (LCD, 7%), medium (MCD, 12%) and high (HCD, 17%) carbohydrate diets for eight weeks. Gut histology revealed the slight infiltration of inflammatory cells and moderate loss of mucous membrane layer in HCD group. Expression of ZO1, occluding, and claudin7 genes and epidermal growth factor receptor (EGFR) gene were significantly decreased in HCD group indicating the impairment of tight junction and epithelial cell regeneration. The results showed the significant (P < 0.05) reduction of antioxidant capacity in HCD group compared to LCD. Furthermore, expression of intestinal ERS-related genes such as IRE1, Eif2α, GRP78, CHOPα and CHOPβ in HCD group was significantly higher than the LCD group. In addition, HCD induced the up-regulated expression of inflammatory (IL-8, IL-1β, TNFα and COX2) and apoptosis (TRAF2, bax, casepase3, caspase8 and casepase9) related genes in fish intestine. The data generated in this study clearly demonstrated that HCD induced ERS and oxidative stress, which promoted intestinal inflammation and apoptosis in juvenile largemouth bass.

Active Ingredients and Potential Mechanisms of the Gan Jiang-Huang Qin-Huang Lian-Ren Shen Decoction against Ulcerative Colitis: A Network Pharmacology and Molecular Docking-Based Study

BACKGROUND

Ulcerative colitis (UC), a chronic and nonspecific inflammatory bowel disease, seriously affects the quality of patients' life. Han Re Bing Yong Fa (treating diseases with both cool- and warm-natured herbs) is a classical therapeutic principle of traditional Chinese medicine (TCM), which is often used to treat chronic diseases, including UC. The Gan Jiang-Huang Qin-Huang Lian-Ren Shen decoction (GJHQHLRSD), a representative of Han Re Bing Yong Fa, is effective in alleviating inflammatory symptoms in UC. However, the pharmacological mechanism underlying its anti-inflammatory effect remains unclear.

METHODS

A network pharmacology strategy, including the construction and analysis of the drug-disease network, was used to explore the complex mechanism of GJHQHLRSD treatment of UC. In addition, molecular docking technology was used to preliminarily examine the binding ability of the potential active components and core therapeutic targets of GJHQHLRSD.

RESULTS

The network pharmacology results revealed 140 targets of GJHQHLRSD which are involved in UC. The PPI network analysis identified seven target genes: BCL2L1, NR3C1, ALOX5, S1PR5, NR1I2, CYP2D6, and LPAR6. The molecular docking results revealed that the following displayed strongest combined effects: EGFR with kaempferol, ERK1 with worenine, STAT3 with Palmidin A, BCL2L1 with diop and VEGFA with ginsenoside Rg3. The KEGG and gene ontology enrichment analyses results indicated that GJHQHLRSD functions by regulating the EGFR signaling pathway in UC treatment. Other effective biological processes involved in UC treatment included cancer-related as well as inflammation and viral infection signaling pathways, such as the "MicroRNAs in cancer," "TNF signaling pathway," and "JAK-STAT signaling pathway."

CONCLUSIONS

This study reflects the multicomponent, multitarget, and multipathway characteristics of the action mechanism of GJHQHLRSD in treating UC. Furthermore, it helps better understand the TCM therapeutic principle of Han Re Bing Yong Fa and explore novel candidate drug targets for UC treatment.

Uncovering the Mechanism of Curcuma in the Treatment of Ulcerative Colitis Based on Network Pharmacology, Molecular Docking Technology, and Experiment Verification

Aim

The incidence of ulcerative colitis (UC) is increasing steadily in developed countries, it is plaguing nearly 1 million people in the United States and European countries, while developing countries have had a rapidly increased incidence over the past decades. Curcuma is widely used in treating malaria, UC, Crohn's disease, and colon cancer, which lead to diarrhea and bloody stool. However, the systemic mechanism of curcuma in treating UC is still unclear. Our work was supposed to expound how does curcuma alleviate UC in a comprehensive and systematic way by network pharmacology, molecular docking, and experiment verification.

Methods

Traditional Chinese Medicine System Pharmacology Database (TCMSP), Shanghai Chemistry & Chemical Industry Data Platform (SGST), and papers published in Chinese Network Knowledge Infrastructure (CNKI) and PubMed were used to collect the chemical constituents of curcuma based on ADME (absorption, distribution, metabolism, and excretion). And effective targets were predicted by Swiss Target Prediction to establish the curcuma-related database. The disease targets of UC were screened by GeneCards and DrugBank databases, and Wayne (Venn) analysis was carried out with curcuma targets to determine the intersection targets. AutoDock software and TCMNPAS system were used to dock the core chemical components of curcuma with key UC targets. Protein interaction (PPI) network was constructed based on the STRING database and Cytoscape software. Gene function GO analysis and KEGG pathway enrichment analysis were carried out by using Metascape database. Finally, HE staining was performed to identify the inflammatory infiltration and expression difference in TNF-α and STAT3 before and after the treatment of curcuma which was verified by immunoblotting.

Results

Twelve active components containing 148 target genes were selected from curcuma. Potential therapeutic targets of curcuma in the treatment of UC were acquired from 54 overlapped targets from UC and curcuma. Molecular docking was used to filter the exact 24 core proteins interacting with compounds whose docking energy is lower than -5.5 and stronger than that of 5-aminosalicylic acid (5-ASA). GO and KEGG analyses showed that these targets were highly correlated with EGFR tyrosine kinase inhibitor resistance, PI3K-Akt signaling pathway, JAK-STAT signaling pathway, MAPK signaling pathway, and inflammatory bowel disease (IBD). Experiments verified curcuma relieved pathological manifestation and decreased the expression of TNF-α and STAT3.

Conclusion

Curcuma relieved the colon inflammation of ulcerative colitis via inactivating TNF pathway, inflammatory bowel disease pathway, and epithelial cell signaling in Helicobacter pylori infection pathway, probably by binding to STAT3 and TNF-α.

ADAM10 and ADAM17 regulate EGFR, c-Met and TNF RI signalling in liver regeneration and fibrosis

ADAM10 and ADAM17 are proteases that affect multiple signalling pathways by releasing molecules from the cell surface. As their substrate specificities partially overlaps, we investigated their concurrent role in liver regeneration and fibrosis, using three liver-specific deficient mouse lines: ADAM10- and ADAM17-deficient lines, and a line deficient for both proteases. In the model of partial hepatectomy, double deficient mice exhibited decreased AKT phosphorylation, decreased release of EGFR activating factors and lower shedding of HGF receptor c-Met. Thus, simultaneous ablation of ADAM10 and ADAM17 resulted in inhibited EGFR signalling, while HGF/c-Met signalling pathway was enhanced. In contrast, antagonistic effects of ADAM10 and ADAM17 were observed in the model of chronic CCl₄ intoxication. While ADAM10-deficient mice develop more severe fibrosis manifested by high ALT, AST, ALP and higher collagen deposition, combined deficiency of ADAM10 and ADAM17 surprisingly results in comparable degree of liver damage as in control littermates. Therefore, ADAM17 deficiency is not protective in fibrosis development per se, but can ameliorate the damaging effect of ADAM10 deficiency on liver fibrosis development. Furthermore, we show that while ablation of ADAM17 resulted in decreased shedding of TNF RI, ADAM10 deficiency leads to increased levels of soluble TNF RI in serum. In conclusion, hepatocyte-derived ADAM10 and ADAM17 are important regulators of growth receptor signalling and TNF RI release, and pathological roles of these proteases are dependent on the cellular context.

Strategies to Target ADAM17 in Disease: From its Discovery to the iRhom Revolution

For decades, disintegrin and metalloproteinase 17 (ADAM17) has been the object of deep investigation. Since its discovery as the tumor necrosis factor convertase, it has been considered a major drug target, especially in the context of inflammatory diseases and cancer. Nevertheless, the development of drugs targeting ADAM17 has been harder than expected. This has generally been due to its multifunctionality, with over 80 different transmembrane proteins other than tumor necrosis factor α (TNF) being released by ADAM17, and its structural similarity to other metalloproteinases. This review provides an overview of the different roles of ADAM17 in disease and the effects of its ablation in a number of in vivo models of pathological conditions. Furthermore, here, we comprehensively encompass the approaches that have been developed to accomplish ADAM17 selective inhibition, from the newest non-zinc-binding ADAM17 synthetic inhibitors to the exploitation of iRhom2 to specifically target ADAM17 in immune cells.

ACE2 contributes to the maintenance of mouse epithelial barrier function

The whole world was hit hard by the coronavirus disease-19 (COVID-19). Given that angiotensin I converting enzyme 2 (ACE2) is the viral entry molecule, understanding ACE2 has become a major focus of current COVID-19 research. ACE2 is highly expressed in the gut, but its role has not been fully understood and thus COVID-19 treatments intending to downregulate ACE2 level may cause untoward side effects. Gaining insight into the functions of ACE2 in gut homeostasis therefore merits closer examination, and is beneficial to find potential therapeutic alternatives for COVID-19. Methods: We took advantage of Ace2 knockout out mice and isolated intestinal organoids to examine the role of ACE2 in intestinal stemness. Inflammatory bowel disease (IBD) mouse model was established by 4% dextran sodium sulfate. LGR5 and KI67 levels were quantitated to reflect the virtue of intestinal stem cells (ISCs). FITC-dextran 4 (FD-4) assay was used to assess intestinal barrier function. Results: Western blotting identified the expression of ACE2 in colon, which was consistent with the results of immunofluorescence and RT-PCR. Moreover, Ace2^−/− organoids showed decreased LRG5 and KI67 levels, and elevated calcium concentration. Furthermore, the permeability of ace2^−/− organoids was markedly increased compared with ace2^+/+ organoids. Collectively, ace2^−/− mice were more susceptible than ace2^+/+ mice to IBD, including earlier bloody stool, undermined intestinal architecture and more pronounced weight loss. Conclusions: Our data reveal that ACE2 contributes to the proliferation of intestinal stem cells and hence orchestrates the mucosal homeostasis.

Stromal metalloproteinases: Crucial contributors to the tumor microenvironment

Proteolytic balance is crucial for the maintenance of tissue homeostasis. In cancer, dysregulated proteolysis is involved in unregulated tissue remodeling and inflammation, leading to the promotion of tumor growth, local invasion, and metastasis. Metalloproteinases, which were first identified as collagen cleaving enzymes, have been shown to extensively degrade extracellular matrix proteins or selectively release cell surface-bound cytokines, growth factors, or their receptors, thereby impacting extracellular matrix integrity, immune cell recruitment and tissue turnover. Although tumor cells produce various metalloproteinases, the major source is thought to be stromal cells infiltrating the tumor. Different types of stromal cells express specific sets of metalloproteinases and their inhibitors, which specifically alter the milieu within the tumor. In this review, recent findings and knowledge regarding metalloproteinases derived from stromal cells during the creation of the tumor microenvironment are described and their contribution to the tumor progression and metastasis discussed.

ADAM-Mediated Signalling Pathways in Gastrointestinal Cancer Formation

Tumour growth is not solely driven by tumour cell-intrinsic mechanisms, but also depends on paracrine signals provided by the tumour micro-environment. These signals comprise cytokines and growth factors that are synthesized as trans-membrane proteins and need to be liberated by limited proteolysis also termed ectodomain shedding. Members of the family of A disintegrin and metalloproteases (ADAM) are major mediators of ectodomain shedding and therefore initiators of paracrine signal transduction. In this review, we summarize the current knowledge on how ADAM proteases on tumour cells but also on cells of the tumour micro-environment contribute to the formation of gastrointestinal tumours, and discuss how these processes can be exploited pharmacologically.

COVID-19 and immunomodulation in IBD

The current coronavirus pandemic is an ongoing global health crisis due to COVID-19, caused by severe acute respiratory syndrome coronavirus 2. Although COVID-19 leads to little or mild flu-like symptoms in the majority of affected patients, the disease may cause severe, frequently lethal complications such as progressive pneumonia, acute respiratory distress syndrome and organ failure driven by hyperinflammation and a cytokine storm syndrome. This situation causes various major challenges for gastroenterology. In the context of IBD, several key questions arise. For instance, it is an important question to understand whether patients with IBD (eg, due to intestinal ACE2 expression) might be particularly susceptible to COVID-19 and the cytokine release syndrome associated with lung injury and fatal outcomes. Another highly relevant question is how to deal with immunosuppression and immunomodulation during the current pandemic in patients with IBD and whether immunosuppression affects the progress of COVID-19. Here, the current understanding of the pathophysiology of COVID-19 is reviewed with special reference to immune cell activation. Moreover, the potential implications of these new insights for immunomodulation and biological therapy in IBD are discussed.

Reciprocal control of ADAM17/EGFR/Akt signaling and miR-145 drives GBM invasiveness

INTRODUCTION

Glioblastoma multiforme (GBM) is one of the most devastating brain malignancies worldwide and is considered to be incurable. However, the mechanisms underlying its aggressiveness remain unclear.

METHODS

The expression of ADAM17 in tissue samples was detected by immunohistochemistry. Knockdown and rescue experiments were used to demonstrate the regulatory effect of ADAM17 on the invasion ability of GBM cells. Western Blot and qPCR were used to detect the expression of related proteins and RNAs. Moreover, a luciferase reporter assay was performed to verify whether miR-145 directly binds to the 3'-UTR of ADAM17.

RESULTS

We revealed that ADAM17 was overexpressed in GBM tissues and correlated positively with poor prognosis. The knockdown of ADAM17 obviously suppressed the invasiveness of GBM cell lines. Furthermore, we found that knockdown of ADAM17 decreased activation of EGFR/Akt/C/EBP-β signaling, and consequently upregulated miR-145 expression in GBM cell lines. Notably, miR-145 directly targeted the ADAM17 3'-UTR and suppressed expression levels of ADAM17.

CONCLUSIONS

Our findings define an ADAM17/EGFR/miR-145 feedback loop that drives the GBM invasion. Reciprocal regulation between ADAM17 and miR-145 results in aberrant activation of EGFR signaling, suggesting that inhibition of ADAM17 expression can be an ideal therapeutic strategy for the treatment of GBM.

Status update on iRhom and ADAM17: It's still complicated

Several membrane-bound proteins with a single transmembrane domain are subjected to limited proteolysis at the cell surface. This cleavage leads to the release of their biologically active ectodomains, which can trigger different signalling pathways. In many cases, this ectodomain shedding is mediated by members of the family of a disintegrins and metalloproteinases (ADAMs). ADAM17 in particular is responsible for the cleavage of several proinflammatory mediators, growth factors, receptors and adhesion molecules. Due to its direct involvement in the release of these signalling molecules, ADAM17 can be positively and negatively involved in various physiological processes as well as in inflammatory, fibrotic and malignant pathologies. This central role of ADAM17 in a variety of processes requires strict multi-level regulation, including phosphorylation, various conformational changes and endogenous inhibitors. Recent research has shown that an early, crucial control mechanism is interaction with certain adapter proteins identified as iRhom1 and iRhom2, which are pseudoproteases of the rhomboid superfamily. Thus, iRhoms have also a decisive influence on physiological and pathophysiological signalling processes regulated by ADAM17. Their characteristic gene expression profiles, the specific consequences of gene knockouts and finally the occurrence of disease-associated mutations suggest that iRhom1 and iRhom2 undergo different gene regulation in order to fulfil their function in different cell types and are therefore only partially redundant. Therefore, there is not only interest in ADAM17, but also in iRhoms as therapeutic targets. However, to exploit the therapeutic potential, the regulation of ADAM17 activity and in particular its interaction with iRhoms must be well understood.

CD9 regulates keratinocyte migration by negatively modulating the sheddase activity of ADAM17

CD9 is a trans-membrane protein, and has recently been implicated in different physiological and cellular processes, such as cell migration and adhesion. According to previous study, down-regulation of CD9 contributes to keratinocyte migration, critical for wound re-epithelialization. Nevertheless, it is widely believed that tetraspanin CD9 does not have ligands or function as the cell surface receptor, rather it is thought to associate with other transmembrane molecules, thereby mediate keratinocyte migration. Little is known about how CD9 associates with transmembrane molecules in migratory keratinocytes. Here, using confocal microscopy, we observed that tetraspanin CD9 and ADAM17 co-localized on the surface of keratinocytes in the course of wound repair in vivo and in vitro. Co-immunoprecipitation experiments demonstrated a direct association between CD9 and ADAM17 in HaCaT cells and C57-MKs. Functional studies revealed that down-regulation or over-expression of CD9 exerted negative regulatory effects on ADAM17 sheddase activity. This activity is involved in CD9-regulated cell motility and migration. Further studies found that ADAM17 inhibitor-TAPI-2 or siADAM17 significantly abolished the enhanced effect of keratinocyte migration induced by CD9 down-regulation. Meanwhile, the sheddase activity of ADAM17 was inhibited by TAPI-2, which decreased this release of AREG and HB-EGF in CD9-silenced HaCat cells and C57-MKs. Importantly, neutralizing antibody against HB-EGF significant weakened keratinocyte migration and motility in CD9-silenced keratinocytes, and the inhibition of CD9-regulated keratinocyte migration by siADAM17 was rescued by addition of recombinant HB-EGF, activating EGFR/ERK pathway. Collectively, our results suggest that ADAM17 sheddase activity is activated by down-regulation of CD9, thereby mediating shedding of HB-EGF and activation of EGFR/ERK signaling, which crucially affects the keratinocyte migration and wound healing.

Extracellular vesicle-associated MMPs: A modulator of the tissue microenvironment

Extracellular vesicles (EVs) are small particles that mediate intercellular communications in local and distant microenvironments. Due to their ability to carry bioactive materials such as proteins, nucleic acids, and lipids, and to transfer their cargo into target cells, EVs are thought to be crucial mediators under pathological and physiological conditions. Recent investigations of their protein profiles have revealed the presence of metalloproteinases such as matrix metalloproteinases (MMPs) in EVs from various cell types and body fluids. Although information regarding the biological and clinical significance of MMPs in EVs is still limited, EV-associated MMPs can alter EV cargo by ectodomain shedding, exerting proteolytic activity following uptake by target cells, or directly contributing to degradation of extracellular matrix proteins surrounding cells. This review focuses on recent findings regarding EV-associated MMPs, and we further discuss their potential involvement in human diseases.

Human rhomboid family-1 modulates clathrin coated vesicle-dependent pro-transforming growth factor α membrane trafficking to promote breast cancer progression

BACKGROUND

Epidermal growth factor receptor (EGFR) signalling is critical in epithelial cancer development. Human rhomboid family-1 (RHBDF1) facilitates the secretion of TGFα, an EGFR ligand, in breast cancer; however, the underlying mechanism remains unclear. We evaluated the role for RHBDF1 in clathrin-coated vesicle (CCV)-dependent pro-TGFα membrane trafficking in breast cancer cells upon stimulation by G-protein coupled receptor (GPCR) agonists.

METHODS

RHBDF1 was silenced in various breast cancer cells using shRNA. TGFα levels, subcellular localization, and secretion were evaluated using ELISA, immunofluorescent staining, and coimmunoprecipitation. Phosphorylation and expression of relevant proteins were measured by western blotting. RHBDF1-dependent cell viability and invasion were measured.

FINDINGS

RHBDF1 mediates GPCR agonist-induced EGFR phosphorylation by promoting TGFα secretion in various types of breast cancer cells. RHBDF1 not only mediates ADAM17-dependent shedding of TGFα, but is essential in membrane trafficking of pro-TGFα. RHBDF1 silencing results in blocking of clathrin uncoating from CCV, a crucial step for the plasma membrane release of pro-TGFα. Interaction of RHBDF1 with auxilin-2, a CCV protein, determines the recruitment of HSC70 to CCV to facilitate clathrin uncoating. RHBDF1 function is required for the proliferation and mobility of breast cancer cells upon stimulation by Sphingosine 1 Phosphate (S1P), a GPCR agonist. We demonstrate a significant correlation between RHBDF1 overexpression and EGFR activation in breast cancer tissues.

INTERPRETATION

RHBDF1 is an indispensable component of the protein trafficking machinery involved in GPCR-mediated EGFR transactivation, and is an attractive therapeutic target for cancer. FUND: National Natural Science Foundation of China (81,672,740 to ZSZ, 81,272,356 and 81,330,029 to LYL).

Monogenic Intestinal Epithelium Defects and the Development of Inflammatory Bowel Disease

The incidence of inflammatory bowel disease (IBD) is increasing worldwide, most notably in young children. The development of disease is a combination of several factors, including genetics, environment, the microbiota, and immune system. Recently, next-generation sequencing has allowed for the identification of novel genetic causes for intestinal disease, including pediatric inflammatory bowel disease (IBD). These IBD genes can generally be grouped into genes causing either primary immunodeficiency or intestinal epithelial defects (the focus of this review). Most of these genes have been functionally validated with in vitro and/or animal models, and have been demonstrated to cause intestinal disease. Intestinal epithelial IBD genes are of particular interest since they are the least amenable to current therapies; therefore, further research is warranted to develop potential therapies. A number of cellular pathways are impacted with intestinal epithelial IBD genes, including intestinal epithelial cell adhesion and generation of reactive oxygen species. Here, we describe the currently known IBD risk alleles and monogenic causal intestinal epithelial genes, their putative roles in preserving intestinal epithelial cell homeostasis, and their implications for IBD pathophysiology.

Loss of PACS-2 delays regeneration in DSS-induced colitis but does not affect the ApcMin model of colorectal cancer

PACS-2 is a multifunctional sorting protein that mediates cell homeostasis. We recently identified PACS-2 in a functional genome-wide siRNA screen for novel regulators of the metalloproteinase ADAM17, the main sheddase for ligands of the ErbB receptor family. Of note, we showed that Pacs2^-/- mice have significantly reduced EGFR activity and proliferative index in the intestinal epithelium. As EGFR signaling is highly mitogenic for intestinal epithelial stem cells, and plays essential roles in intestinal epithelial regeneration and tumor development, we have now examined the role of PACS-2 in these processes. Specifically, we analyzed the role of Pacs2-deficiency in a DSS-induced colitis model as well as in the genetic Apc^Min colon cancer model. We now report that loss of PACS-2 delays tissue regeneration after colonic injury with little effect on key inflammatory parameters. We did however not observe any apparent effects on tumor formation driven by excessive proliferative signaling downstream from APC-deficiency. Our findings reveal that the role of PACS-2 in regulating ADAM17-mediated shedding is not an obligate requirement for the epithelium to respond to the strong inflammatory or tumorigenic inducers in the models assessed here.

布拉氏酵母菌散对活动期溃疡性结肠炎钙卫蛋白及炎性因子的影响

目的

观察布拉氏酵母菌散结合美沙拉嗪对活动期溃疡性结肠炎(ulcerative colitis, UC)的临床疗效及对钙卫蛋白(calprotectin, CP)、炎性因子的影响.

方法

选取65例2016-01/2016-10于大庆市第四医院消化科符合诊断及纳入标准的UC患者, 随机分为对照组(32例)和治疗组(33例), 对照组给予美沙拉嗪肠溶片治疗, 治疗组在对照组的基础上加服布拉氏酵母菌散. 2组患者疗程均为6 wk, 分别观察2组患者治疗前、后临床症状, 粪便CP及血清炎性因子γ-干扰素(interferon-γ, IFN-γ)、肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)、白细胞介素-6(interleukin-6, IL-6)的影响.

结果

治疗组总有效率明显优于对照组(93.75% vs 81.81%, P<0.05); 2组治疗后Mayo疾病活动指数均较本组治疗前显著降低(P<0.01), 治疗后组间比较, 治疗组明显优于对照组(P<0.01); 2组治疗后CP、IFN-γ、TNF-α、IL-6均较本组治疗前显著降低(P<0.01), 治疗后组间比较, 治疗组明显优于对照组(P<0.01); 治疗组随访复发率优于对照组(7.4% vs 24.2%, P<0.05).

结论

布拉氏酵母菌散结合美沙拉嗪能够显著降低UC患者CP、IFN-γ、TNF-α、IL-6水平, 改善临床症状及肠道黏膜损伤, 且复发率低, 疗效显著.

Growth Hormone Resistance-Special Focus on Inflammatory Bowel Disease

Growth hormone (GH) plays major anabolic and catabolic roles in the body and is important for regulating several aspects of growth. During an inflammatory process, cells may develop a state of GH resistance during which their response to GH stimulation is limited. In this review, we will emphasize specific mechanisms governing the formation of GH resistance in the active phase of inflammatory bowel disease. The specific molecular effects mediated through individual inflammatory mediators and processes will be highlighted to provide an overview of the transcriptional, translational and post-translational inflammation-mediated impacts on the GH receptor (GHR) along with the impacts on GH-induced intracellular signaling. We also will review GH’s effects on mucosal healing and immune cells in the context of experimental colitis, human inflammatory bowel disease and in patients with short bowel syndrome.

Zeolite-Containing Mixture Supplementation Ameliorated Dextran Sodium Sulfate-Induced Colitis in Mice by Suppressing the Inflammatory Bowel Disease Pathway and Improving Apoptosis in Colon Mucosa

Inflammatory bowel disease (IBD) is induced by multiple environmental factors, and there is still no known treatment capable of curing the disease completely. We propose a zeolite-containing mixture (Hydryeast^®, HY)-a multi-component nutraceutical of which the main ingredients are Azumaceramics (mixture of zeolite and oyster shell burned under high temperature), citric acid, red rice yeast (monascus) and calcium stearate-as a nutraceutical intervention in IBD to ameliorate dextran sodium sulfate (DSS)-induced colitis. We show the mechanism through integrated omics using transcriptomics and proteomics. C57BL6 mice were given an AIN-93G basal diet or a 0.8% HY containing diet and sterilized tap water for 11 days. Colitis was then induced by 1.5% (w/v) DSS-containing water for 9 days. HY fed mice showed significantly improved disease activity index and colon length compared to DSS mice. Colonic mucosa microarray analysis plus RT-PCR results indicate HY supplementation may ameliorate inflammation by inhibiting the intestinal inflammatory pathway and suppress apoptosis by curbing the expression of genes like tumor protein 53 and epidermal growth factor receptor and by upregulating epithelial protection-related proteins such as epithelial cell adhesion molecule and tenascin C, thus maintaining mucosal immune homeostasis and epithelial integrity, mirroring the proteome analysis results. HY appears to have a suppressive effect on colitis.

Hyaluronan-Binding Protein Involved in Hyaluronan Depolymerization Controls Endochondral Ossification through Hyaluronan Metabolism

Hyaluronan (HA) plays an important role in the development and maintenance of tissues, and its degradation is implicated in many pathologic conditions. We recently reported that HA-binding protein involved in HA depolymerization (CEMIP; alias HYBID/KIAA1199) is a key molecule in HA depolymerization, but its developmental and pathologic functions remain elusive. We generated Hybid-deficient mice using the Cre/locus of crossover in P1 (loxP) system and analyzed their phenotypes. Hybid-deficient mice were viable and fertile, but their adult long bones were shorter than those of wild-type animals. Hybid-deficient mice showed lengthening of hypertrophic zone in the growth plate until 4 weeks after birth. There were fewer capillaries and osteoclasts at the chondroosseous junction in the Hybid-deficient mice compared with the wild-type mice. In situ hybridization demonstrated that Hybid was expressed by hypertrophic chondrocytes at the chondroosseous junction. Cultured primary chondrocytes expressed higher levels of Hybid than did osteoblasts or osteoclasts, and the Hybid expression in the chondrocytes was up-regulated after maturation to hypertrophic chondrocytes. High-molecular-weight HA was accumulated in the lengthened hypertrophic zone in Hybid-deficient mice. In addition, high-molecular-weight HA significantly reduced cell growth and tube formation in vascular endothelial growth factor-stimulated or -nonstimulated endothelial cells. HA metabolism by HYBID is involved in endochondral ossification during postnatal development by modulation of angiogenesis and osteoclast recruitment at the chondroosseous junction.

ADAM17 is a Tumor Promoter and Therapeutic Target in Western Diet-associated Colon Cancer

PURPOSE

Epidermal growth factor receptors (EGFR) are required for tumor promotion by Western diet. The metalloprotease, ADAM17 activates EGFR by releasing pro-EGFR ligands. ADAM17 is regulated by G-protein-coupled receptors, including CXCR4. Here we investigated CXCR4-ADAM17 crosstalk and examined the role of ADAM17 in tumorigenesis.

EXPERIMENTAL DESIGN

We used CXCR4 inhibitor, AMD3100 and ADAM17 inhibitor, BMS566394 to assess CXCR4-ADAM17 crosstalk in colon cancer cells. We compared the expression of CXCR4 ligand, CXCL2, and ADAM17 in mice fed Western diet versus standard diet. Separately, mice were treated with marimastat, a broad-spectrum ADAM17 inhibitor, or AMD3100 to assess EGFR activation by ADAM17 and CXCR4. Using Apc-mutant Min mice, we investigated the effects of ADAM17/10 inhibitor INCB3619 on tumorigenesis. To assess the effects of colonocyte ADAM17, mice with ADAM17 conditional deletion were treated with azoxymethane (AOM). ADAM17 expression was also compared in colonocytes from primary human colon cancers and adjacent mucosa.

RESULTS

CXCL12 treatment activated colon cancer cell EGFR signals, and CXCR4 or ADAM17 blockade reduced this activation. In vivo, Western diet increased CXCL12 in stromal cells and TGFα in colonocytes. Marimastat or AMD3100 caused >50% reduction in EGFR signals (P < 0.05). In Min mice, INCB3619 reduced EGFR signals in adenomas and inhibited intestinal tumor multiplicity (P < 0.05). In the AOM model, colonocyte ADAM17 deletion reduced EGFR signals and colonic tumor development (P < 0.05). Finally, ADAM17 was upregulated >2.5-fold in human malignant colonocytes.

CONCLUSIONS

ADAM17 is a Western diet-inducible enzyme activated by CXCL12-CXCR4 signaling, suggesting the pathway: Western diet→CXCL12→CXCR4→ADAM17→TGFα→EGFR. ADAM17 might serve as a druggable target in chemoprevention strategies. Clin Cancer Res; 23(2); 549-61. ©2016 AACR.