Collagen degradation and neutrophilic infiltration: a vicious circle in inflammatory bowel disease

How the Western Diet Thwarts the Epigenetic Efforts of Gut Microbes in Ulcerative Colitis and Its Association with Colorectal Cancer

Ulcerative colitis (UC) is an autoimmune disease in which the immune system attacks the colon, leading to ulcer development, loss of colon function, and bloody diarrhea. The human gut ecosystem consists of almost 2000 different species of bacteria, forming a bioreactor fueled by dietary micronutrients to produce bioreactive compounds, which are absorbed by our body and signal to distant organs. Studies have shown that the Western diet, with fewer short-chain fatty acids (SCFAs), can alter the gut microbiome composition and cause the host's epigenetic reprogramming. Additionally, overproduction of H2S from the gut microbiome due to changes in diet patterns can further activate pro-inflammatory signaling pathways in UC. This review discusses how the Western diet affects the microbiome's function and alters the host's physiological homeostasis and susceptibility to UC. This article also covers the epidemiology, prognosis, pathophysiology, and current treatment strategies for UC, and how they are linked to colorectal cancer.

Targeted delivery of the probiotic Saccharomyces boulardii to the extracellular matrix enhances gut residence time and recovery in murine colitis

Probiotic and engineered microbe-based therapeutics are an emerging class of pharmaceutical agents. They represent a promising strategy for treating various chronic and inflammatory conditions by interacting with the host immune system and/or delivering therapeutic molecules. Here, we engineered a targeted probiotic yeast platform wherein Saccharomyces boulardii is designed to bind to abundant extracellular matrix proteins found within inflammatory lesions of the gastrointestinal tract through tunable antibody surface display. This approach enabled an additional 24-48 h of probiotic gut residence time compared to controls and 100-fold increased probiotic concentrations within the colon in preclinical models of ulcerative colitis in female mice. As a result, pharmacodynamic parameters including colon length, colonic cytokine expression profiles, and histological inflammation scores were robustly improved and restored back to healthy levels. Overall, these studies highlight the potential for targeted microbial therapeutics as a potential oral dosage form for the treatment of inflammatory bowel diseases.

RNA Expression of MMP12 Is Strongly Associated with Inflammatory Bowel Disease and Is Regulated by Metabolic Pathways in RAW 264.7 Macrophages

Macrophage metalloelastase or matrix metalloproteinase-12 (MMP12) is a macrophage-specific proteolytic enzyme involved in the physiopathology of many inflammatory diseases, including inflammatory bowel disease. Although previously published data suggested that the modulation of MMP12 in macrophages could be a determinant for the development of intestinal inflammation, scarce information is available on the mechanisms underlying the regulation of MMP12 expression in those phagocytes. Therefore, in this study, we aimed to delineate the association of MMP12 with inflammatory bowel disease and the molecular events leading to the transcriptional control of this metalloproteinase. For that, we used publicly available transcriptional data. Also, we worked with the RAW 264.7 macrophage cell line for functional experiments. Our results showed a strong association of MMP12 expression with the severity of inflammatory bowel disease and the response to relevant biological therapies. In vitro assays revealed that the inhibition of mechanistic target of rapamycin complex 1 (mTORC1) and the stimulation of the AMP-activated protein kinase (AMPK) signaling pathway potentiated the expression of Mmp12. Additionally, AMPK and mTOR required a functional downstream glycolytic pathway to fully engage with Mmp12 expression. Finally, the pharmacological inhibition of MMP12 abolished the expression of the proinflammatory cytokine Interleukin-6 (Il6) in macrophages. Overall, our findings provide a better understanding of the mechanistic regulation of MMP12 in macrophages and its relationship with inflammation.

Role of platelet factor 4 in arteriovenous fistula maturation failure: What do we know so far?

The rate of arteriovenous fistula (AVF) maturation failure remains unacceptably high despite continuous efforts on technique improvement and careful pre-surgery planning. In fact, half of all newly created AVFs are unable to be used for hemodialysis (HD) without a salvage procedure. While vascular stenosis in the venous limb of the access is the culprit, the underlying factors leading to vascular narrowing and AVF maturation failure are yet to be determined. We have recently demonstrated that AVF non-maturation is associated with post-operative medial fibrosis and fibrotic stenosis, and post-operative intimal hyperplasia (IH) exacerbates the situation. Multiple pathological processes and signaling pathways are underlying the stenotic remodeling of the AVF. Our group has recently indicated that a pro-inflammatory cytokine platelet factor 4 (PF4/CXCL4) is upregulated in veins that fail to mature after AVF creation. Platelet factor 4 is a fibrosis marker and can be detected in vascular stenosis tissue, suggesting that it may contribute to AVF maturation failure through stimulation of fibrosis and development of fibrotic stenosis. Here, we present an overview of the how PF4-mediated fibrosis determines AVF maturation failure.

Lactate Protects Intestinal Epithelial Barrier Function from Dextran Sulfate Sodium-Induced Damage by GPR81 Signaling

The dysregulation of the intestinal epithelial barrier significantly contributes to the inflammatory progression of ulcerative colitis. Recent studies have indicated that lactate, produced by gut bacteria or derived from fermented foods, plays a key role in modulating inflammation via G-protein-coupled receptor 81 (GPR81). In this study, we aimed to investigate the potential role of GPR81 in the progression of colitis and to assess the impact of lactate/GPR81 signaling on intestinal epithelial barrier function. Our findings demonstrated a downregulation of GPR81 protein expression in patients with colitis. Functional verification experiments showed that Gpr81-deficient mice exhibited more severe damage to the intestinal epithelial barrier and increased susceptibility to DSS-induced colitis, characterized by exacerbated oxidative stress, elevated inflammatory cytokine secretion, and impaired expression of tight-junction proteins. Mechanistically, we found that lactate could suppress TNF-α-induced MMP-9 expression and prevent the disruption of tight-junction proteins by inhibiting NF-κB activation through GPR81 in vitro. Furthermore, our study showed that dietary lactate could preserve intestinal epithelial barrier function against DSS-induced damage in a GPR81-dependent manner in vivo. Collectively, these results underscore the crucial involvement of the lactate/GPR81 signaling pathway in maintaining intestinal epithelial barrier function, providing a potential therapeutic strategy for ulcerative colitis.

Matrix metalloproteinases as biomarkers and therapeutic targets in colitis-associated cancer

Colorectal cancer (CRC) remains a major cause of morbidity and mortality. Therapeutic approaches for advanced CRC are limited and rarely provide long-term benefit. Enzymes comprising the 24-member matrix metalloproteinase (MMP) family of zinc- and calcium-dependent endopeptidases are key players in extracellular matrix degradation, a requirement for colon tumor expansion, invasion, and metastasis; hence, MMPs are an important research focus. Compared to sporadic CRC, less is known regarding the molecular mechanisms and the role of MMPs in the development and progression of colitis-associated cancer (CAC) - CRC on a background of chronic inflammatory bowel disease (IBD) - primarily ulcerative colitis and Crohn's disease. Hence, the potential of MMPs as biomarkers and therapeutic targets for CAC is uncertain. Our goal was to review data regarding the role of MMPs in the development and progression of CAC. We sought to identify promising prognostic and therapeutic opportunities and novel lines of investigation. A key observation is that since MMPs may be more active in early phases of CAC, using MMPs as biomarkers of advancing neoplasia and as potential therapeutic targets for adjuvant therapy in those with advanced stage primary CAC rather than overt metastases may yield more favorable outcomes.

Extracellular Matrix Orchestration of Tissue Remodeling in the Chronically Inflamed Mouse Colon

BACKGROUND & AIMS

Chronic inflammatory illnesses are debilitating and recurrent conditions associated with significant comorbidities, including an increased risk of developing cancer. Extensive tissue remodeling is a hallmark of such illnesses, and is both a consequence and a mediator of disease progression. Despite previous characterization of epithelial and stromal remodeling during inflammatory bowel disease, a complete understanding of its impact on disease progression is lacking.

METHODS

A comprehensive proteomic pipeline using data-independent acquisition was applied to decellularized colon samples from the Muc2 knockout (Muc2KO) mouse model of colitis for an in-depth characterization of extracellular matrix remodeling. Unique proteomic profiles of the matrisomal landscape were extracted from prepathologic and overt colitis. Integration of proteomics and transcriptomics data sets extracted from the same murine model produced network maps describing the orchestrating role of matrisomal proteins in tissue remodeling during the progression of colitis.

RESULTS

The in-depth proteomic workflow used here allowed the addition of 34 proteins to the known colon matrisomal signature. Protein signatures of prepathologic and pathologic colitic states were extracted, differentiating the 2 states by expression of small leucine-rich proteoglycans. We outlined the role of this class and other matrisomal proteins in tissue remodeling during colitis, as well as the potential for coordinated regulation of cell types by matrisomal ligands.

CONCLUSIONS

Our work highlights a central role for matrisomal proteins in tissue remodeling during colitis and defines orchestrating nodes that can be exploited in the selection of therapeutic targets.

Neutrophils in Inflammatory Diseases: Unraveling the Impact of Their Derived Molecules and Heterogeneity

Inflammatory diseases involve numerous disorders and medical conditions defined by an insufficient level of self-tolerance. These diseases evolve over the course of a multi-step process through which environmental variables play a crucial role in the emergence of aberrant innate and adaptive immunological responses. According to experimental data accumulated over the past decade, neutrophils play a significant role as effector cells in innate immunity. However, neutrophils are also involved in the progression of numerous diseases through participation in the onset and maintenance of immune-mediated dysregulation by releasing neutrophil-derived molecules and forming neutrophil extracellular traps, ultimately causing destruction of tissues. Additionally, neutrophils have a wide variety of functional heterogeneity with adverse effects on inflammatory diseases. However, the complicated role of neutrophil biology and its heterogeneity in inflammatory diseases remains unclear. Moreover, neutrophils are considered an intriguing target of interventional therapies due to their multifaceted role in a number of diseases. Several approaches have been developed to therapeutically target neutrophils, involving strategies to improve neutrophil function, with various compounds and inhibitors currently undergoing clinical trials, although challenges and contradictions in the field persist. This review outlines the current literature on roles of neutrophils, neutrophil-derived molecules, and neutrophil heterogeneity in the pathogenesis of autoimmune and inflammatory diseases with potential future therapeutic strategies.

The occurrence and development of vertebral osteoporosis regulated by IL-8

Vertebral osteoporotic fracture is a common type of fracture, and the incidence is higher in the elderly. However, the relationship between vertebral osteoporotic fractures and interleukin-8 (IL-8) remains unclear. A total of 163 patients with osteoporotic vertebral fractures were recruited. Clinical and follow-up data were recorded, and the expression levels of IL1, MMP9, IL-8, and C-reactive protein in blood were measured. Pearson Chi-square test and Spearman correlation coefficient were used to analyze the relationship between vertebral osteoporotic fractures and related parameters. Univariate and multivariate logistic regression and univariate and multivariate Cox proportional hazards regression were used for further analysis. Pearson chi-square test, Spearman correlation coefficient and Logistic regression analysis showed that IL1 and IL-8 were significantly associated with vertebral osteoporotic fractures. Univariate Cox regression analysis showed that age and IL-8 expression level were significantly associated with maintenance time from recovery to recurrence of vertebral osteoporotic fractures. Multivariate Cox regression analysis showed that IL-8 expression level was significantly associated with maintenance time from recovery to recurrence of vertebral osteoporotic fractures. The higher the expression level of IL-8, the more likely it is to develop vertebral osteoporotic fracture, and the more likely it is to relapse in a short time.

Lung Involvement in Inflammatory Bowel Diseases: Shared Pathways and Unwanted Connections

Inflammatory bowel diseases (IBDs) are chronic, relapsing inflammatory disorders of the gastrointestinal tract, frequently associated with extraintestinal manifestations (EIMs) that can severely affect IBD patients' quality of life, sometimes even becoming life-threatening. Respiratory diseases have always been considered a rare and subsequently neglected extraintestinal manifestations of IBD. However, increasing evidence has demonstrated that respiratory involvement is frequent in IBD patients, even in the absence of respiratory symptoms. Airway inflammation is the most common milieu of IBD-related involvement, with bronchiectasis being the most common manifestation. Furthermore, significant differences in prevalence and types of involvement are present between Crohn's disease and ulcerative colitis. The same embryological origin of respiratory and gastrointestinal tissue, in addition to exposure to common antigens and cytokine networks, may all play a potential role in the respiratory involvement. Furthermore, other causes such as drug-related toxicity and infections must always be considered. This article aims at reviewing the current evidence on the association between IBD and respiratory diseases. The purpose is to raise awareness of respiratory manifestation among IBD specialists and emphasize the need for identifying respiratory diseases in early stages to promptly treat these conditions, avoid worsening morbidity, and prevent lung damage.

An Analysis of the Content of Metalloproteinases in the Intestinal Wall of Patients with Crohn's Disease

One of the inflammatory bowel diseases is Crohn's disease. Although this term has been used in the medical community since 1932, a significant increase in the number of publications occurs at the end of the 20th century and the beginning of the 21st century. Crohn's disease is a disease that cannot be fully cured. In many cases, it is chronic, i.e., recurrent. All preventive and therapeutic measures taken by doctors are aimed at inhibiting the development of the disease and minimizing the occurrence of any potential "side effects" resulting from the developing disease. One of the diagnostic methods is the qualitative and quantitative determination of metalloproteinases in inflammatory tissues and in the blood. The aim of the study was the quantitative and qualitative determination of metalloproteinases in inflammatory bowel tissues in patients diagnosed with Crohn's disease. The in vitro study was performed on surgical tissues from patients diagnosed with Crohn's disease. The results show that in inflammatory tissues the concentration of metalloproteinases -3, -7, -8, -9 was higher compared to tissues taken from the resection margin without signs of inflammation, defined as healthy. The experiment confirmed that the biochemical test, which is the determination of metalloproteinases in tissues, is a useful diagnostic tool to differentiate inflammatory from non-inflammatory tissues.

Therapeutic inhibition of CXCR1/2: where do we stand?

Mounting experimental evidence from in vitro and in vivo animal studies points to an essential role of the CXCL8-CXCR1/2 axis in neutrophils in the pathophysiology of inflammatory and autoimmune diseases. In addition, the pathogenetic involvement of neutrophils and the CXCL8-CXCR1/2 axis in cancer progression and metastasis is increasingly recognized. Consequently, therapeutic targeting of CXCR1/2 or CXCL8 has been intensively investigated in recent years using a wide array of in vitro and animal disease models. While a significant benefit for patients with unwanted neutrophil-mediated inflammatory conditions may be expected from a potential clinical use of inhibitors, their use in severe infections or sepsis might be problematic and should be carefully and thoroughly evaluated in animal models and clinical trials. Translating the approaches using inhibitors of the CXCL8-CXCR1/2 axis to cancer therapy is definitively a new and promising research avenue, which parallels the ongoing efforts to clearly define the involvement of neutrophils and the CXCL8-CXCR1/2 axis in neoplastic diseases. Our narrative review summarizes the current literature on the activation and inhibition of these receptors in neutrophils, key inhibitor classes for CXCR2 and the therapeutic relevance of CXCR2 inhibition focusing here on gastrointestinal diseases.

LC-MS/MS method for proline-glycine-proline and acetylated proline-glycine-proline in human plasma

The extracellular cellular matrix (ECM) maintains tissue structure and regulates signaling functions by continuous degradation and remodeling. Inflammation or other disease conditions activate proteases including matrix metalloproteinases (MMPs) that degrade ECM proteins and in particular generate fragments of collagen and elastin, some of which are biologically active ECM peptides or matrikines. Stepwise degradation of collagen by MMP 8, 9 and prolyl endopeptidase release the matrikine proline-glycine-proline (PGP) and its product acetyl-PGP (AcPGP). These peptides are considered as potential biomarkers and therapeutic targets for many disease conditions such as chronic lung disease, heart disease, and cancer. However, there is no published, validated method for the measurement of PGP and AcPGP in plasma and therefore, we developed a sensitive, selective and reliable, isotope dilution LC-multiple reaction monitoring MS method for their determination in human plasma. The chromatographic separation of PGP and AcPGP was achieved in 3 min using Jupiter column with a gradient consisting of acidified acetonitrile and water at a flow rate of 0.5 ml/min. The limit of detection (LOD) for PGP and AcPGP was 0.01 ng/ml and the limit of quantification (LOQ) was 0.05 ng/ml and 0.1 ng/ml, respectively. Precision and accuracy values for all analytes were within 20 % except for the lowest QC of 0.01 ng/ml. The mean extraction recoveries of these analytes were > 90 % using a Phenomenex Phree cartridge and the matrix effect was < 15 % for all the QCs for PGP and AcPGP except the lowest QC. The stability of PGP and AcPGP was > 90 % in several tested conditions including autosampler use, storage at -80 °C, and after 6 times freeze-thaw cycles. Using this method, we successfully extracted and determined PGP levels in human plasma from healthy and COPD subjects. Therefore, this method is suitable for quantification of these peptides in the clinical setting.

Hydroethanolic Extract of Fritillariae thunbergii Bulbus Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis by Enhancing Intestinal Barrier Integrity

The incidence of ulcerative colitis (UC), an inflammatory disorder of the gastrointestinal tract, has rapidly increased in Asian countries over several decades. To overcome the limitations of conventional drug therapies, including biologics for UC management, the development of herbal medicine-derived products has received continuous attention. In this study, we evaluated the beneficial effects of a hydroethanolic extract of Fritillariae thunbergii Bulbus (FTB) in a mouse model of DSS-induced UC. The DSS treatment successfully induced severe colonic inflammation and ulceration. However, the severity of colitis was reduced by the oral administration of FTB. Histopathological examination showed that FTB alleviated the infiltration of inflammatory cells (e.g., neutrophils and macrophages), damage to epithelial and goblet cells in the colonic mucosal layer, and fibrotic lesions. Additionally, FTB markedly reduced the gene expression of proinflammatory cytokines and extracellular matrix remodeling. Immunohistochemical analysis showed that FTB alleviated the decrease in occludin and zonula occludens-1 expression induced by DSS. In a Caco-2 monolayer system, FTB treatment improved intestinal barrier permeability in a dose-dependent manner and increased tight junction expression. Overall, FTB has potential as a therapeutic agent through the improvement of tissue damage and inflammation severity through the modulation of intestinal barrier integrity.

Exploring the mechanism of Xingpi Capsule in diarrhea predominant-irritable bowel syndrome treatment based on multiomics technology

BACKGROUND

Xingpi Capsule (XP), a commercially available over-the-counter herbal medicine in China, plays a prominent role in treating diarrhea-predominant irritable bowel syndrome (IBS-D). Nevertheless, the potential mechanisms remain unclear.

PURPOSE

This study aimed to investigate XP efficacy in IBS-D and elucidate the underlying molecular mechanisms.

METHODS

A rat IBS-D model was established by senna decoction gavage combined with restraint stress and swimming exhaustion. The changes in rat body weight and stool were recorded daily. Colon pathological changes and the number of colonic goblet cells of rats were observed by hematoxylin-eosin (HE) staining and Alcian blue plus periodic acid-Schiff (AB-PAS) staining, respectively. The expression of Occludin, a tight-junction-associated protein, was examined via immunohistochemistry. Images of colonic microvilli were obtained by TEM. Western blotting (WB) was used to analyze the protein expression of the ASK1/P38 MAPK pathway. The composition of the rat intestinal microbiota was detected by 16S rRNA sequencing. Changes in colonic metabolites were evaluated by liquid chromatography-mass spectrometry (LC-MS). Changes in colon RNA expression were assessed by RNA sequencing (RNA-Seq). The nontoxic range of hypoxanthine (HPX) was screened by Cell Counting Kit-8 (CCK8), the cell model of human colonic epithelial cells (NCM460) induced by lipopolysaccharide (LPS) was established, and the effective concentration of HPX was screened by CCK8. After transfection of pcDNA3.1-MAP3K5, Hoechst 33,342 staining, flow cytometry to detect cell apoptosis, and immunofluorescence to detect the fluorescence changes of ASK1 and ZO-1. WB detection of ASK1/P38 MAPK pathway protein expression changes.

RESULTS

XP increased the body weight of IBS-D patients and reduced the loose stool rate, loose stool index, and Bristo score. In addition, XP mitigated colon lesions, increased the number of goblet cells and the expression of Occludin, and prevented severe distortion and effacement of the microvillous structure. Specifically, 16S rRNA gene sequence analysis showed that XP decreased the abundance of Desulfurium and Prevotella 9 at the phylum and genus levels while increasing the abundance of Bacteroides at the genus level. RNA-Seq combined with WB validation showed that XP exerted antidiarrheal effects by inhibiting the ASK1/P38 MAPK signaling pathway. Additionally, XP also increased the relative expression level of the metabolite HPX, as revealed by untargeted metabolomics analysis. Impressively, the correlation analysis between 16S rRNA sequencing and LC-MS suggested that HPX and Prevotella 9 are negatively correlated, which indicated that XP might increase the content of HPX by reducing the abundance of Prevotella 9. Meanwhile, a negative correlation between HPX and ASK1 was indicated through RNA-Seq and LC-MS, which suggested that the inhibition of ASK1 (Map3k5) may be ascribed to the increase in HPX after XP treatment. In vitro experiments have proven that HPX can alleviate LPS-induced NCM460 damage, specifically manifested as enhancing cell viability, reducing cell apoptosis, increasing ZO-1 expression, reducing the fluorescence intensity of MAP3K5 in the model group, and inhibiting the expression of ASK1/P38 MAPK pathway proteins. The protective effect of HPX was reversed after transfection with pcDNA 3.1-MAP3K5, which fully demonstrated that the protective mechanism of HPX was achieved by inhibiting MAP3K5 and its downstream pathways.

CONCLUSION

XP displayed multifaceted protection against IBS-D in rats by regulating the intestinal microbiota, increasing the relative expression level of HPX, a metabolite of the microbiota, and inhibiting the ASK1/P38 MAPK signaling pathway.

Protective Mechanism of Ethyl Gallate against Intestinal Ischemia-Reperfusion Injury in Mice by in Vivo and in Vitro Studies Based on Transcriptomics

Intestinal ischemia-reperfusion injury (IIRI) is a common clinical disease that can be life-threatening in severe cases. This study aimed to investigate the effects of ethyl gallate (EG) on IIRI and its underlying mechanisms. A mouse model was established to mimic human IIRI by clamping the superior mesenteric artery. Transcriptomics techniques were used in conjunction with experiments to explore the potential mechanisms of EG action. Intestinal histomorphological damage, including intestinal villi damage and mucosal hemorrhage, was significantly reversed by EG. EG also alleviated the oxidative stress, inflammation, and intestinal epithelial apoptosis caused by IIRI. 2592 up-regulated genes and 2754 down-regulated genes were identified after EG treatment, and these differential genes were enriched in signaling pathways, including fat digestion and absorption, and extracellular matrix (ECM) receptor interactions. In IIRI mouse intestinal tissue, expression of the differential protein matrix metalloproteinase 9 (MMP9), as well as its co-protein NF-κB-p65, was significantly increased, while EG inhibited the expression of MMP9 and NF-κB-p65. In Caco-2 cells in an established oxygen-glucose deprivation/reperfusion model (OGD/R), EG significantly reversed the decrease in intestinal barrier trans-epithelial electrical resistance (TEER). However, in the presence of MMP9 inhibitors, EG did not reverse the decreasing trend in TEER. This study illustrates the protective effect and mechanism of action of EG on IIRI and, combined with in vivo and in vitro experiments, it reveals that MMP9 may be the main target of EG action. This study provides new scientific information on the therapeutic effects of EG on IIRI.

The Pregnane X Receptor and Indole-3-Propionic Acid Shape the Intestinal Mesenchyme to Restrain Inflammation and Fibrosis

BACKGROUND & AIMS

Fibrosis is a common complication of inflammatory bowel diseases (IBDs). The pregnane X receptor (PXR) (encoded by NR1I2) suppresses intestinal inflammation and has been shown to influence liver fibrosis. In the intestine, PXR signaling is influenced by microbiota-derived indole-3-propionic acid (IPA). Here, we sought to assess the role of the PXR in regulating intestinal inflammation and fibrosis.

METHODS

Intestinal inflammation was induced using dextran sulfate sodium (DSS). Fibrosis was assessed in wild-type (WT), Nr1i2^-/-, epithelial-specific Nr1i2^-/-, and fibroblast-specific Nr1i2^-/- mice. Immune cell influx was quantified by flow cytometry and cytokines by Luminex. Myofibroblasts isolated from WT and Nr1i2^-/- mice were stimulated with cytomix or lipopolysaccharide, and mediator production was assessed by quantitative polymerase chain reaction and Luminex.

RESULTS

After recovery from DSS-induced colitis, WT mice exhibited fibrosis, a response that was exacerbated in Nr1i2^-/- mice. This was correlated with greater neutrophil infiltration and innate cytokine production. Deletion of the PXR in fibroblasts, but not the epithelium, recapitulated this phenotype. Inflammation and fibrosis were reduced by IPA administration, whereas depletion of the microbiota exaggerated intestinal fibrosis. Nr1i2-deficient myofibroblasts were hyperresponsive to stimulation, producing increased levels of inflammatory mediators compared with WT cells. In biopsies from patients with active Crohn's disease (CD) and ulcerative colitis (UC), expression of NR1I2 was reduced, correlating with increased expression of fibrotic and innate immune genes. Finally, both CD and UC patients exhibited reduced levels of fecal IPA.

CONCLUSIONS

These data highlight a role for IPA and its interactions with the PXR in regulating the mesenchyme and the development of inflammation and fibrosis, suggesting microbiota metabolites may be a vital determinant in the progression of fibrotic complications in IBD.

Gut microbiota influence anastomotic healing in colorectal cancer surgery through modulation of mucosal proinflammatory cytokines

OBJECTIVE

Colorectal cancer (CRC) is the third most diagnosed cancer, and requires surgical resection and reconnection, or anastomosis, of the remaining bowel to re-establish intestinal continuity. Anastomotic leak (AL) is a major complication that increases mortality and cancer recurrence. Our objective is to assess the causal role of gut microbiota in anastomotic healing.

DESIGN

The causal role of gut microbiota was assessed in a murine AL model receiving faecal microbiota transplantation (FMT) from patients with CRC collected before surgery and who later developed or not, AL. Anastomotic healing and gut barrier integrity were assessed after surgery. Bacterial candidates implicated in anastomotic healing were identified using 16S rRNA gene sequencing and were isolated from faecal samples to be tested both in vitro and in vivo.

RESULTS

Mice receiving FMT from patients that developed AL displayed poor anastomotic healing. Profiling of gut microbiota of patients and mice after FMT revealed correlations between healing parameters and the relative abundance of Alistipes onderdonkii and Parabacteroides goldsteinii. Oral supplementation with A. onderdonkii resulted in a higher rate of leaks in mice, while gavage with P. goldsteinii improved healing by exerting an anti-inflammatory effect. Patients with AL and mice receiving FMT from AL patients presented upregulation of mucosal MIP-1α, MIP-2, MCP-1 and IL-17A/F before surgery. Retrospective analysis revealed that patients with AL present higher circulating neutrophil and monocyte counts before surgery.

CONCLUSION

Gut microbiota plays an important role in surgical colonic healing in patients with CRC. The impact of these findings may extend to a vast array of invasive gastrointestinal procedures.

Inflammatory Bowel Disease-Associated Gut Commensals Degrade Components of the Extracellular Matrix

Extracellular matrix (ECM) remodeling has emerged as a key feature of inflammatory bowel disease (IBD), and ECM fragments have been proposed as markers of clinical disease severity. Recent studies report increased protease activity in the gut microbiota of IBD patients. Nonetheless, the relationship between gut microbiota and ECM remodeling has remained unexplored. We hypothesized that members of the human gut microbiome could degrade the host ECM and that bacteria-driven remodeling, in turn, could enhance colonic inflammation. Through a variety of in vitro assays, we first confirmed that multiple bacterial species found in the human gut are capable of degrading specific ECM components. Clinical stool samples obtained from ulcerative colitis patients also exhibited higher levels of proteolytic activity in vitro, compared to those of their healthy counterparts. Furthermore, culture supernatants from bacteria species that are capable of degrading human ECM accelerated inflammation in dextran sodium sulfate (DSS)-induced colitis. Finally, we identified several of the bacterial proteases and carbohydrate degrading enzymes (CAZymes) that are potentially responsible for ECM degradation in vitro. Some of these protease families and CAZymes were also found in increased abundance in a metagenomic cohort of IBD. These results demonstrate that some commensal bacteria in the gut are indeed capable of degrading components of human ECM in vitro and suggest that this proteolytic activity may be involved in the progression of IBD. A better understanding of the relationship between nonpathogenic gut microbes, host ECM, and inflammation could be crucial to elucidating some of the mechanisms underlying host-bacteria interactions in IBD and beyond. IMPORTANCE Healthy gut epithelial cells form a barrier that keeps bacteria and other substances from entering the blood or tissues of the body. Those cells sit on scaffolding that maintains the structure of the gut and informs our immune system about the integrity of this barrier. In patients with inflammatory bowel disease (IBD), breaks are formed in this cellular barrier, and bacteria gain access to the underlying tissue and scaffolding. In our study, we discovered that bacteria that normally reside in the gut can modify and disassemble the underlying scaffolding. Additionally, we discovered that changes to this scaffolding affect the onset of IBD in mouse models of colitis as well as the abilities of these mice to recover. We propose that this new information will reveal how breaks in the gut wall lead to IBD and will open up new avenues by which to treat patients with IBD.

NLRP3 activation in neutrophils induces lethal autoinflammation, liver inflammation, and fibrosis

Sterile inflammation is a central element in liver diseases. The immune response following injurious stimuli involves hepatic infiltration of neutrophils and monocytes. Neutrophils are major effectors of liver inflammation, rapidly recruited to sites of inflammation, and can augment the recruitment of other leukocytes. The NLRP3 inflammasome has been increasingly implicated in severe liver inflammation, fibrosis, and cell death. In this study, the role of NLRP3 activation in neutrophils during liver inflammation and fibrosis was investigated. Mouse models with neutrophil-specific expression of mutant NLRP3 were developed. Mutant mice develop severe liver inflammation and lethal autoinflammation phenocopying mice with a systemic expression of mutant NLRP3. NLRP3 activation in neutrophils leads to a pro-inflammatory cytokine and chemokine profile in the liver, infiltration by neutrophils and macrophages, and an increase in cell death. Furthermore, mutant mice develop liver fibrosis associated with increased expression of pro-fibrogenic genes. Taken together, the present work demonstrates how neutrophils, driven by the NLRP3 inflammasome, coordinate other inflammatory myeloid cells in the liver, and propagate the inflammatory response in the context of inflammation-driven fibrosis.

Human intestinal myofibroblasts deposited collagen VI enhances adhesiveness for T cells - A novel mechanism for maintenance of intestinal inflammation

OBJECTIVE

Inflammatory bowel diseases (IBD) cause chronic intestinal damage and extracellular matrix (ECM) remodeling. The ECM may play an active role in inflammation by modulating immune cell functions, including cell adhesion, but this hypothesis has not been tested in IBD.

DESIGN

Primary human intestinal myofibroblast (HIMF)-derived ECM from IBD and controls, 3D decellularized colon or ECM molecule-coated scaffolds were tested for their adhesiveness for T cells. Matrisome was analysed via proteomics. Functional integrin blockade was used to investigate the underlying mechanism. Analysis of the pediatric Crohn's disease (CD) RISK inception cohort was used to explore an altered ECM gene expression as a potential predictor for a future complicated disease course.

RESULTS

HIMF-derived ECM and 3D decellularized colonic ECM from IBD bound more T cells compared to control. Control HIMFs exposed to the pro-inflammatory cytokines Iinterleukin-1β (IL-1β) and tumor necrosis factor (TNF) increased, and to transforming growth factor-β1 (TGF-β1) decreased ECM adhesiveness to T cells. Matrisome analysis of the HIMF-derived ECM revealed collagen VI as a major culprit for differences in T cell adhesion. Collagen VI knockdown in HIMF reduced adhesion T cell as did the blockage of integrin αvβ1. Elevated gene expression of collagen VI in biopsies of pediatric CD patients was linked to risk for future stricturing disease.

CONCLUSION

HIMF-derived ECM in IBD binds a remarkably enhanced number of T cells, which is dependent on Collagen VI and integrin αvβ1. Collagen VI expression is a risk factor for a future complicated CD course. Blocking immune cells retention may represent a novel approach to treatment in IBD.

Inflammatory bowel disease biomarkers

Inflammatory bowel disease (IBD) is characterized as chronic inflammation in the gastrointestinal tract, which includes two main subtypes, Crohn's disease and ulcerative colitis. Endoscopy combined with biopsy is the most effective way to establish IBD diagnosis and disease management. Imaging techniques have also been developed to monitor IBD. Although effective, the methods are expensive and invasive, which leads to pain and discomfort. Alternative noninvasive biomarkers are being explored as tools for IBD prognosis and disease management. This review focuses on novel biomarkers that have emerged in recent years. These serological biomarkers and microRNAs could potentially be used for disease management in IBD, thereby decreasing patient discomfort and morbidity.

Selective Inhibitors of Medium-Size S1' Pocket Matrix Metalloproteinases: A Stepping Stone of Future Drug Discovery

Among various matrix metalloproteinases (MMPs), MMPs having medium-size S1' pockets are established as promising biomolecular targets for executing crucial roles in cancer, cardiovascular diseases, and neurodegenerative diseases. However, no such MMP inhibitors (MMPIs) are available to date as drug candidates despite a lot of continuous research work for more than three decades. Due to a high degree of structural resemblance among these MMPs, designing selective MMPIs is quite challenging. However, the variability and uniqueness of the S1' pockets of these MMPs make them promising targets for designing selective MMPIs. In this perspective, the overall structural aspects of medium-size S1' pocket MMPs including the unique binding patterns of enzyme-inhibitor interactions have been discussed in detail to acquire knowledge regarding selective inhibitor designing. This overall knowledge will surely be a curtain raiser for the designing of selective MMPIs as drug candidates in the future.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

Pathological features-based targeted delivery strategies in IBD therapy: A mini review

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by a complex and dysfunctional immune response. Currently, IBD is incurable, and patients with IBD often need to take drugs for life. However, as the traditional systemic treatment strategies for IBD do not target the site of inflammation, only limited efficacy can be obtained from them. Moreover, the possibility of serious side effects stemming from the systemic administration or redistribution of drugs in the body is high when conventional drug formulations are used. Therefore, a targeted drug-delivery system for IBD should be considered. Based on the pathological features related to IBD, the new targeted drug-delivery strategy can directly transfer the drug to the inflammatory site, thus enhancing the accumulation of the drugs and reducing side effects. This article reviews the pathological features of IBD and the application of the IBD-targeted delivery system based on different pathological features, and discusses the challenges and new prospects in this field.

Pathophysiological Concepts and Management of Pulmonary Manifestation of Pediatric Inflammatory Bowel Disease

Pulmonary manifestation (PM) of inflammatory bowel disease (IBD) in children is a rare condition. The exact pathogenesis is still unclear, but several explanatory concepts were postulated and several case reports in children were published. We performed a systematic Medline search between April 1976 and April 2022. Different pathophysiological concepts were identified, including the shared embryological origin, “miss-homing” of intestinal based neutrophils and T lymphocytes, inflammatory triggering via certain molecules (tripeptide proline-glycine-proline, interleukin 25), genetic factors and alterations in the microbiome. Most pediatric IBD patients with PM are asymptomatic, but can show alterations in pulmonary function tests and breathing tests. In children, the pulmonary parenchyma is more affected than the airways, leading histologically mainly to organizing pneumonia. Medication-associated lung injury has to be considered in pulmonary symptomatic pediatric IBD patients treated with certain agents (i.e., mesalamine, sulfasalazine or infliximab). Furthermore, the risk of pulmonary embolism is generally increased in pediatric IBD patients. The initial treatment of PM is based on corticosteroids, either inhaled for the larger airways or systemic for smaller airways and parenchymal disease. In summary, this review article summarizes the current knowledge about PM in pediatric IBD patients, focusing on pathophysiological and clinical aspects.

Stretch Causes Cell Stress and the Downregulation of Nrf2 in Primary Amnion Cells

Nuclear-factor-E2-related factor 2 (Nrf2) is a key transcription factor for the regulation of cellular responses to cellular stress and inflammation, and its expression is significantly lower after spontaneous term labor in human fetal membranes. Pathological induction of inflammation can lead to adverse pregnancy outcomes such as pre-eclampsia, preterm labor, and fetal death. As stretch forces are known to act upon the fetal membranes in utero, we aimed to ascertain the effect of stretch on Nrf2 to increase our understanding of the role of this stimulus on cells of the amnion at term. Our results indicated a significant reduction in Nrf2 expression in stretched isolated human amnion epithelial cells (hAECs) that could be rescued with sulforaphane treatment. Downregulation of Nrf2 as a result of stretch was accompanied with activation of proinflammatory nuclear factor-kB (NF-kB) and increases in LDH activity, ROS, and HMGB1. This work supports stretch as a key modulator of cellular stress and inflammation in the fetal membranes. Our results showed that the modulation of the antioxidant response pathway in the fetal membranes through Nrf2 activation may be a viable approach to improve outcomes in pregnancy.

Interleukin-26 Expression in Inflammatory Bowel Disease and Its Immunoregulatory Effects on Macrophages

Background and Aim

Interleukin-26 (IL-26) has been implicated in several chronic inflammatory diseases. However, its role in inflammatory bowel disease (IBD) remains to be elucidated. We aimed to investigate IL-26 expression in IBD and its immunoregulatory effects on macrophages.

Methods

We assessed IL-26 expression in the intestinal mucosa and blood samples of IBD patients and healthy controls (HC). The associations between the clinical characteristics of IBD and IL-26 expression levels in serum and peripheral blood mononuclear cells (PBMCs) were investigated. In addition, the transcriptional changes in THP-1 macrophages exposed to IL-26 were determined by RNA sequencing and validated with qRT-PCR, ELISA and western blots.

Results

Compared with HC, in IBD patients, IL-26 expression levels were elevated in the inflamed intestinal mucosa, and reduced in serum and PBMCs. IL-26 mRNA levels in PBMCs, but not serum IL-26 levels, were inversely correlated with disease activity in IBD. Furthermore, IL-26 mRNA levels in PBMCs were significantly lower in patients with complicated Crohn's disease. A total of 1,303 differentially expressed protein-coding genes were identified between untreated and IL-26-treated macrophages. The up-regulated genes showed enrichment in some inflammatory and immune-related processes and pathways. Additionally, GSEA showed that neutrophil, monocyte, and lymphocyte chemotaxis was significantly enriched in IL-26-treated macrophages. Further validation revealed that IL-26 promotes the secretion of multiple inflammatory cytokines and chemokines and upregulates the expression of adhesion molecules, MMP-8, and MMP-9 while inhibiting MMP-1 in macrophages.

Conclusion

Compared with HC, in IBD patients, IL-26 levels were elevated in the inflamed intestinal mucosa, and reduced in the peripheral blood. The transcriptional changes in macrophages exposed to IL-26 suggest that IL-26 may amplify the aberrant immune response in IBD by activating macrophages.

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.

Potential Roles of Exosomal lncRNAs in the Intestinal Mucosal Immune Barrier

The intestinal mucosal immune barrier protects the host from the invasion of foreign pathogenic microorganisms. Immune cells and cytokines in the intestinal mucosa maintain local and systemic homeostasis by participating in natural and adaptive immunity. Deficiency of the intestinal mucosal immune barrier is associated with a variety of intestinal illnesses. Exosomes are phospholipid bilayer nanovesicles that allow cell-cell communication by secreting physiologically active substances including proteins, lipids, transcription factors, mRNAs, micro-RNAs (miRNAs), and long noncoding RNAs (lncRNAs). Exosomal lncRNAs are involved in immune cell differentiation and the modulation of the immune response. This review briefly introduces the potential role of exosomal lncRNAs in the intestinal mucosal immune barrier and discusses their relevance to intestinal illnesses.

Considerations for understanding protein measurements: Identification of formation, degradation and more pathological relevant epitopes

OBJECTIVES

There is a need for precision medicine and an unspoken promise of an optimal approach for identification of the right patients for value-based medicine based on big data. However, there may be a misconception that measurement of proteins is more valuable than measurement of fewer selected biomarkers. In population-based research, variation may be somewhat eliminated by quantity. However, this fascination of numbers may limit the attention to and understanding of the single. This review highlights that protein measurements (with collagens as examples) may mean different things depending on the targeted epitope - formation or degradation of tissues, and even signaling potential of proteins.

DESIGN AND METHODS

PubMed was searched for collagen, neo-epitope, biomarkers.

RESULTS

Ample examples of assays with specific epitopes, either pathological such as HbA1c, or domain specific such as pro-peptides, which total protein arrays would not have identified were evident.

CONCLUSIONS

We suggest that big data may be considered as the funnel of data points, in which most important parameters will be selected. If the technical precision is low or the biological accuracy is limited, and we include suboptimal quality of biomarkers, disguised as big data, we may not be able to fulfill the promise of helping patients searching for the optimal treatment. Alternatively, if the technical precision of the total protein quantification is high, but we miss the functional domains with the most considerable biological meaning, we miss the most important and valuable information of a given protein. This review highlights that measurements of the same protein in different ways may provide completely different meanings. We need to understand the pathological importance of each epitope quantified to maximize protein measurements.

Immunological Traits of Patients with Coexistent Inflammatory Bowel Disease and Periodontal Disease: A Systematic Review

This systematic review assessed studies that evaluated the immunological traits of patients with both inflammatory bowel disease (IBD) and periodontal disease. An electronic search for literature was conducted on PubMed, Embase, Scopus, Cochrane and Web of Science. Studies that evaluated the immunological response in patients with IBD and periodontal disease were considered eligible for inclusion. A total of 6 cross-sectional studies of 275 patients were included. Immunological analyses were performed in gingival crevicular fluid, saliva, serum, intestinal and gingival biopsies. Four studies identified that the presence of IBD and periodontal disease was associated with higher levels of prostaglandin E2, aMMP8, IL-18 and S100A12, respectively, when compared to patients without the coexistence of both diseases. Furthermore, another study identified higher aMMP-8 levels with increasing severity of periodontitis in Crohn’s disease patients. The quality of overall evidence ranged from high to low due to the observational nature of contributing studies. The coexistence of IBD and periodontal disease seems to be associated with a more responsive inflammatory reaction compared with individuals having one or the other. More randomized controlled studies evaluating the coexistence of IBD and periodontitis are required to better explore the immunological interplay between them.

Neutrophil extracellular traps in inflammatory bowel diseases: Implications in pathogenesis and therapeutic targets

Crohn's disease (CD) and ulcerative colitis (UC) are the two main forms of inflammatory bowel disease (IBD). Among the various immune cells involved in IBD, neutrophils are the first to infiltrate and appear to contribute to the impairment of the epithelial barrier, destruction of tissues by oxidative and proteolytic damage, as well as to the perpetuation of inflammation by the release of cytokines and chemokines associated with pro-inflammatory effects. In addition to basic effector mechanisms, such as phagocytosis and chemotaxis, neutrophils can also form extracellular traps (NETs), which is made up of a mesh-like structure - which contains its chromatin (DNA + histones) together with granules and enzymes, such as myeloperoxidase (MPO) and neutrophilic elastase (NE) - and that acts as a trap that can result in the death of extracellular pathogens and/or can promote tissue damage. Recent evidence indicates that NETs also play an important and significant role in the pathogenesis of IBD. Previous studies have reported increased levels of NETs in tissue and serum samples from patients with IBD, as well as in experimental colitis. In this review, we discuss current knowledge about the formation of NETs and their role in the pathophysiology of IBD, pointing out potential mechanisms by which NETs promote tissue damage, as well as their involvement in complications associated with IBD. In addition, we propose potential targets for therapy to regulate the production of NETs, making it possible to expand the current spectrum of therapies for IBD.

Pterostilbene Attenuates High-Fat Diet and Dextran Sulfate Sodium-Induced Colitis via Suppressing Inflammation and Intestinal Fibrosis in Mice

The worldwide prevalence of obesity has significantly increased over the past few decades. It is currently believed that obesity is a risk factor for developing inflammatory bowel disease. Pterostilbene (PTS), a naturally occurring stilbene from blueberries, is known to have anticancer, anti-inflammation, antifibrosis, and antiobesity effects. The preventive effect of PTS on the susceptibility of high-fat diet (HFD) to dextran sulfate sodium (DSS)-induced colitis in mice was investigated. Beginning at 5 weeks of age, C57BL/6J mice were fed a normal diet, 50% HFD alone, or containing PTS, and DSS (2.5%, w/v) was given in drinking water at week 9 and week 11. The results demonstrated that PTS significantly attenuated HFD and DSS-induced plasma interleukin-6 accumulation. Moreover, PTS suppressed HFD/DSS-induced formation of aberrant crypt foci and reduced the colon weight-to-length ratio in HFD/DSS-induced colitis mice. Furthermore, PTS inhibited interleukin-1β (IL-1β), the C/EBP homologous protein (CHOP), cyclooxygenase-2, and transforming growth factor beta-1 (TGF-β1)/mothers against decapentaplegic homolog 2 expression and maintained mucin2 (Muc2) and E-cadherin expressions. In addition, post-treatment with PTS also decreased the colon weight-to-length ratio and loss of Muc2. Moreover, the CHOP, IL-1β, matrix metalloproteinase-2, and TGF-β1 expressions were significantly decreased in HFD/DSS-induced colitis mice after post-treatment with PTS. In conclusion, the results of the present study suggest that PTS is of significant interest for the prevention of HFD/DSS-induced colitis in C57BL/6J mice.

Predicting disease course in ulcerative colitis using stool proteins identified through an aptamer-based screen

In the search for improved stool biomarkers for inflammatory bowel disease (IBD), an aptamer-based screen of 1129 stool proteins was conducted using stool samples from an IBD cohort. Here we report that of the 20 proteins subsequently validated by ELISA, stool Ferritin, Fibrinogen, Haptoglobin, Hemoglobin, Lipocalin-2, MMP-12, MMP-9, Myeloperoxidase, PGRP-S, Properdin, Resistin, Serpin A4, and TIMP-1 are significantly elevated in both ulcerative colitis (UC) and Crohn's disease (CD) compared to controls. When tested in a longitudinal cohort of 50 UC patients at 4 time-points, fecal Fibrinogen, MMP-8, PGRP-S, and TIMP-2 show the strongest positive correlation with concurrent PUCAI and PGA scores and are superior to fecal calprotectin. Unlike fecal calprotectin, baseline stool Fibrinogen, MMP-12, PGRP-S, TIMP-1, and TIMP-2 can predict clinical remission at Week-4. Here we show that stool proteins identified using the comprehensive aptamer-based screen are superior to fecal calprotectin alone in disease monitoring and prediction in IBD.

Prolyl Endopeptidase Gene Disruption Improves Gut Dysbiosis and Non-alcoholic Fatty Liver Disease in Mice Induced by a High-Fat Diet

The gut-liver axis is increasingly recognized as being involved in the pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD). Prolyl endopeptidase (PREP) plays a role in gut metabolic homeostasis and neurodegenerative diseases. We investigated the role of PREP disruption in the crosstalk between gut flora and hepatic steatosis or inflammation in mice with NAFLD. Wild-type mice (WT) and PREP gene knocked mice (PREP^gt) were fed a low-fat diet (LFD) or high-fat diet (HFD) for 16 or 24 weeks. Murine gut microbiota profiles were generated at 16 or 24 weeks. Liver lipogenesis-associated molecules and their upstream mediators, AMP-activated protein kinase (AMPK) and sirtuin1 (SIRT1), were detected using RT-PCR or western blot in all mice. Inflammatory triggers and mediators from the gut or infiltrated inflammatory cells and signal mediators, such as p-ERK and p-p65, were determined. We found that PREP disruption modulated microbiota composition and altered the abundance of several beneficial bacteria such as the butyrate-producing bacteria in mice fed a HFD for 16 or 24 weeks. The level of butyrate in HFD-PREP^gt mice significantly increased compared with that of the HFD-WT mice at 16 weeks. Interestingly, PREP disruption inhibited p-ERK and p-p65 and reduced the levels of proinflammatory cytokines in response to endotoxin and proline-glycine-proline, which guided macrophage/neutrophil infiltration in mice fed a HFD for 24 weeks. However, at 16 weeks, PREP disruption, other than regulating hepatic inflammation, displayed improved liver lipogenesis and AMPK/SIRT1 signaling. PREP disruption may target multiple hepatic mechanisms related to the liver, gut, and microbiota, displaying a dynamic role in hepatic steatosis and inflammation during NAFLD. PREP might serve as a therapeutic target for NAFLD.

Helicobacter hepaticus Induce Colitis in Male IL-10-/- Mice Dependent by Cytolethal Distending Toxin B and via the Activation of Jak/Stat Signaling Pathway

It has been well documented that cytolethal distending toxin (CDT) from Helicobacter hepaticus (H. hepaticus), Campylobacter jejuni (C. jejuni) and other Gram-negative intestinal pathogens is linked to the inflammatory bowel disease (IBD). However, the mechanisms underlying the progression of H. hepaticus induced colitis remains unclear. In this study, male B6.129P2-IL10^tm1Cgn/J mice were infected by H. hepaticus and ΔCdtB H. hepaticus for 6, 12, 18, and 24 weeks. Histopathology, H. hepaticus colonization levels, expression of inflammatory cytokines, signaling pathways, and content of NO in proximal colon were examined. We found that Cytolethal distending toxin subunit B (CdtB) deletion had no influence on colonization ability of H. hepaticus in colon of B6.129P2-IL10^tm1cgn/J mice, and there was no significant difference in abundance of colonic H. hepaticus over infection duration. H. hepaticus aggravated rectocele and proximal colonic inflammation, especially at 24 WPI, while ΔCdtB H. hepaticus could not cause significant symptom. Furthermore, mRNA levels of Il-6, Tnf-α, Il-1β, and iNOS significantly increased in the proximal colon of H. hepaticus-infected mice compared to ΔCdtB H. hepaticus infected group from 12 WPI to 24 WPI. In addition, the elevated content of NO and activated Stat3 and Jak2 in colon were observed in H. hepaticus infected mice. These data demonstrated that CdtB promote colitis development in male B6.129P2-IL10^tm1Cgn/J mice by induction of inflammatory response and activation of Jak-Stat signaling pathway.

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.

Intestinal epithelial cells related lncRNA and mRNA expression profiles in dextran sulphate sodium-induced colitis

Intestinal epithelial barrier damage caused by intestinal epithelial cells (IECs) dysfunction plays a crucial role in the pathogenesis and development of inflammatory bowel disease (IBD). Recently, some studies have suggested the emerging role of long non-coding RNAs (lncRNAs) in IBD. The aim of this study was to reveal lncRNAs and mRNA expression profiles in IECs from a mouse model of colitis and to expand our understanding in the intestinal epithelial barrier regulation. IECs from the colons of wild-type mice and dextran sulphate sodium (DSS)-induced mice were isolated for high-throughput RNA-sequencing. A total of 254 up-regulated and 1013 down-regulated mRNAs and 542 up-regulated and 766 down-regulated lncRNAs were detected in the DSS group compared with the Control group. Four mRNAs and six lncRNAs were validated by real-time quantitative PCR. Function analysis showed that dysregulated mRNAs participated in TLR7 signalling pathway, IL-1 receptor activity, BMP receptor binding and IL-17 signalling pathway. Furthermore, the possibility of indirect interactions between differentially expressed mRNAs and lncRNAs was illustrated by the competing endogenous RNA (ceRNA) network. LncRNA ENSMUST00000128026 was predicted to bind to mmu-miR-6899-3p, regulating Dnmbp expression. LncRNA NONMMUT143162.1 was predicted to competitively bind to mmu-miR-6899-3p, regulating Tnip3 expression. Finally, the protein-protein interaction (PPI) network analysis was constructed with 311 nodes and 563 edges. And the highest connectivity degrees were Mmp9, Fpr2 and Ccl3. These results provide novel insights into the functions of lncRNAs and mRNAs involved in the regulation of the intestinal epithelial barrier.

Compound sophorae decoction enhances intestinal barrier function of dextran sodium sulfate induced colitis via regulating notch signaling pathway in mice

BACKGROUND

Compound sophorae decoction (CSD), a Chinese Herbal decoction, is frequently clinically prescribed for patients suffered from ulcerative colitis (UC) characterized by bloody diarrhea. Yet, the underlying mechanism about how this formulae works is remain elusive.

METHODS

In the present study, the experimental colitis in C57BL/6 J mice was induced by oral administration of standard diets containing 3% dextran sodium sulfate (DSS), and CSD was given orally for treatment at the same time. The clinical symptoms including stool and body weight were recorded each day, and colon length and its histopathological changes were observed. Apoptosis of colonic epithelium was studied by detecting protein expression of cleaved caspase-3, and cell proliferation by Ki-67 immunohistochemistry. Tight junction complex like ZO-1 and occludin were also determined by transmission electron microscope and immunofluorescence. The concentration of FITC-dextran 4000 was measured to evaluate intestinal barrier permeability and possible signaling pathway was investigated. Mucin2 (MUC2) and notch pathway were tested through western blot. The M1/M2 ratio in spleen and mesenteric lymph nodes were detected by flow cytometry. And the mRNA levels of iNOS and Arg1 were examined by qRT-PCR.

RESULTS

CSD could significantly alleviate the clinical manifestations and pathological damage. Body weight loss and DAI score of mice with colitis were improved and shortening of colon was inhibited. The administration of CSD was able to reduce apoptotic epithelial cells and facilitate epithelial cell regeneration. Increased intestinal permeability was reduced in DSS-induced colitis mice. In addition, CSD treatment obviously up-regulated the expression of ZO-1 and occludin and the secretion of MUC2, regulated notch signaling, and decreased the ratio of M1/M2.

CONCLUSIONS

These data together suggest that CSD can effectively mitigate intestinal inflammation, promote phenotypic change in macrophage phenotype and enhance colonic mucosal barrier function by, at least in part, regulating notch signaling in mice affected by DSS-induced colitis.

Suppression of lncRNA MALAT1 reduces pro-inflammatory cytokines production by regulating miR-150-5p/ZBTB4 axis through JAK/STAT signal pathway in systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a common chronic disease occurring in children. Increasing studies have demonstrated that long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of diverse human diseases. This study aimed to explore the role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and its mechanism in sJIA. We found that the expression of MALAT1, the plasma level of pro-inflammatory cytokines (IL-6, IL-17, IL-1β, and TNF-α) as well as MMP-8 and MMP-9 production were significantly elevated in sJIA patients. Moreover, we observed that the production of these cytokines in peripheral blood mononuclear cells (PBMCs) from sJIA patients were reduced after MALAT1 knockdown. Furthermore, bioinformatics analysis predicted that MALAT1 might bind to miR-150-5p and ZBTB4 was a downstream target gene of miR-150-5p. Besides, rescue assays revealed that MALAT1 knockdown-mediated suppressive effects on cytokine production could be reversed by ZBTB4 overexpression. In addition, MALAT1 activated the JAK/STAT signaling by upregulating ZBTB4 expression. In summary, our findings demonstrated that MALAT1 promoted pro-inflammatory cytokine and MMP production by targeting the miR-150-5p/ZBTB4 axis through JAK/STAT signaling pathway in sJIA, suggesting that MALAT1 may have a potential diagnostic biomarker for the pathogenesis and therapy of sJIA.

89Zr-pro-MMP-9 F(ab')2 detects colitis induced intestinal and kidney fibrosis

Intestinal fibrosis is a common complication of inflammatory bowel disease but remains difficult to detect. Matrix metalloproteases (MMPs) have key roles in fibrosis and are therefore potential targets for fibrosis detection. We determined whether immunoPET of F(ab′)₂ antibody fragments targeting MMPs detects colitis induced colonic fibrosis. Mice were administered 2% dextran sulfate sodium treated water for 1 cycle (inflamed) or 3 cycles (fibrotic), or were untreated (control). Colonic and kidney collagen, innate cytokine, MMPs and fecal MPO concentrations were analyzed by multiplex/ELISA. α-pro-MMP-9 F(ab′)₂ fragments were engineered and conjugated to ⁸⁹Zr for PET imaging, ex-vivo Cherenkov analysis and bio-distribution. Colonic innate cytokine concentrations and fecal myeloperoxidase were increased in inflamed mice but not fibrotic mice, while collagen concentrations were increased in fibrotic mice. MMPs were increased in inflamed mice, but only pro-MMP-9 remained increased in fibrotic mice. ⁸⁹Zr-pro-MMP-9 F(ab′)₂ uptake was increased in the intestine but also in the kidney of fibrotic mice, where collagen and pro-MMP-9 concentrations were increased. ⁸⁹Zr-pro-MMP-9 F(ab′)₂ detects colitis induced intestinal fibrosis and associated kidney fibrosis.

Neutrophilic infiltration in organ-on-a-chip model of tissue inflammation

The multiphasic etiology of tissue inflammation and the fundamental immunological differences between species render inflammatory pathologies difficult to recapitulate in animal models, and account for the paucity of therapies that are successfully translated from rodents to humans. Here, we present a human-relevant organ-on-a-chip platform for experimental inflammatory diseases. We created an immunocompetent in vitro gut model by incorporating intestinal epithelial and immune cells into microfluidic chambers that permit cell movement across an extracellular matrix (ECM) and fluidic channels. This is the first model that integrates a mucosal barrier, a three-dimensional ECM, resident and infiltrating immune cells, and simulates a functional crosstalk that ultimately triggers cellular processes representative of inflammation. Under homeostatic conditions, enterocytes form a tight epithelium and subepithelial macrophages are non-activated. Introduction of pro-inflammatory mediators triggers macrophage activation and inflammation-induced intestinal barrier leakiness. Neutrophils in a parallel, matrix-separated non-epithelial channel are attracted by such a pro-inflammatory microenvironment and migrate through the extracellular matrix, further exacerbating tissue inflammation and damage. With this model, we provide the foundations to recapitulate and investigate the onset of tissue inflammation in a controlled, human-relevant system.

Crude Turmeric Extract Improves the Suppressive Effects of Lactobacillus rhamnosus GG on Allergic Inflammation in a Murine Model of House Dust Mite-Induced Asthma

There is a strong correlation between dysregulation of the gastrointestinal microbiota and development of allergic diseases. The most prevalent therapies for relieving asthma symptoms are associated with serious side effects, and therefore novel approaches are needed. Our objective was to elucidate whether oral administration of Lactobacillus rhamnosus GG (LGG) as a probiotic or turmeric powder (TP) as a prebiotic or both as a synbiotic mitigate allergic inflammation including lung function, airway inflammatory cell infiltration, Th2 cytokines/chemokine in a murine model of house dust mite (HDM)-induced asthma. BALB/c mice were intranasally sensitized and challenged with HDM received TP (20 mg/Kg mouse), or/and LGG (10⁵ or 10⁷ cfu/ml), or both orally. Interestingly, the synbiotic intervention (HDM-TP-LGG E7) specifically suppress the developement of airway hyperresponsiveness in response to methacholine. Besides, our synbiotic, TP, and LGG strongly down-regulated eosinophilia, IL-5, CCL17, IL-13. In terms of T cell response, CD4⁺ Th2 cells and CD4⁺ Th17 population were reduced in the splenocytes of the treatment groups compared to control. The synbiotic group not only elevated CD25⁺Foxp3⁺Treg frequency compared to asthmatic group, but also increased T reg cells compared to the probiotic group. The synbiotic also indicated the superior effect in suppressing Th2 cells compared to probiotic. Although, TP and LGG alone displayed suppressive effects, this study showed that the combination therapy consisting of TP and LGG (synbiotic) is more effective in some of the parameters than either of the treatments alone. This novel synbiotic, might be considered as a potential food-based drug for translational medicine and can possibly be used along with corticosteroid treatment.

N-Acetyl-Seryl-Aspartyl-Lysyl-Proline Mitigates Experimental Colitis Through Inhibition of Intestinal Mucosal Inflammatory Responses via MEK-ERK Signaling

N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is an endogenous immunomodulatory peptide that is generated from thymosin β4 (Tβ4) through stepwise hydrolysis, involving meprin-α and prolyl endopeptidase (PREP). It is well acknowledged that AcSDKP exerts beneficial effects on multiple cardiovascular and renal diseases. However, the functional role of AcSDKP in inflammatory bowel disease (IBD) remains poorly understood. Here, we aimed to assess the content of AcSDKP in patients with IBD and investigate the impact of AcSDKP on intestinal inflammation in IBD. We found that in the inflamed mucosal specimens of patients with ulcerative colitis, the expression levels of Tβ4 and meprin-α were decreased, while PREP was expressed at similar levels to non-inflamed mucosa. In vitro, AcSDKP inhibited the expression of proinflammatory factors in intestinal epithelial cells partially by reducing the activation of MEK-ERK signaling. In vivo studies showed that transgenic mice, with lower levels of AcSDKP, were more vulnerable to dextran sulfate sodium (DSS)-induced colitis and exhibited more severe intestinal inflammatory responses. On the other hand, exogenous AcSDKP infusion significantly attenuated the clinical symptoms and intestinal mucosal inflammation in DSS-induced mice. In conclusion, results from this study demonstrated the anti-inflammatory function of AcSDKP within the intestine and suggest that AcSDKP has a promising therapeutic potential for IBD treatment.

Berberine prevents primary peritoneal adhesion and adhesion reformation by directly inhibiting TIMP-1

Peritoneal adhesions are fibrous tissues that tether organs to one another or to the peritoneal wall and represent the major cause of postsurgical morbidity. Enterolysis at repeat surgeries induces adhesion reformation that is more difficult to prevent than primary adhesion. Here we studied the preventive effects of different approaches of berberine treatment for primary adhesion, and its effects on adhesion reformation compared to Interceed. We found the primary adhesion was remarkably prevented by berberine through intraperitoneal injection 30 min before abrasive surgery (pre-berberine) or direct addition into injured cecum immediately after the surgery (inter-berberine). Rats with adhesion reformation had a more deteriorative collagen accumulation and tissue injury in abrasive sites than rats with primary adhesion. The dysregulated TIMP-1/MMP balance was observed in patients after surgery, as well as adhesion tissues from primary adhesion or adhesion reformation rats. Inter-berberine treatment had a better effect for adhesion reformation prevention than Interceed. Berberine promoted the activation of MMP-3 and MMP-8 by directly blocking TIMP-1 activation core, which was reversed by TIMP-1 overexpression in fibroblasts. In conclusion, this study suggests berberine as a reasonable approach for preventing primary adhesion formation and adhesion reformation.

Human PZP and common marmoset A2ML1 as pregnancy related proteins

While pregnancy-related proteins (PRP) are known to contribute to immunotolerance during pregnancy, their significance to development of invasive placenta is unclear. We compared PRP expression in humans and the common marmoset (Callithrix jacchus), a new-world monkey. Invasive placenta was observed at the maternal-foetal interface of marmoset placenta from green fluorescent protein (GFP)-expressing foetus and wild type mother. The pregnancy zone protein (PZP) and alpha-2 macroglobulin-like 1 (A2ML1) proteins exhibited the most prominent increase in expression during the second trimester in humans and marmoset, respectively. In humans, PZP accumulated at the maternal-foetal interface and A2ML1 accumulated in the amnion. Similarly, A2ML1 mRNA was detected in marmoset placenta. These proteins belong to the A2M family of protease inhibitors, and both PZP and A2ML1 share around 90% homology between human and marmoset and have highly conserved structures. However, the protease-reacting bait regions of the proteins had lower homology (56.8–60.7% in proteins) relative to the rest of the sequence. Notably, the cleavage site of a proinflammatory proline-endopeptidase was preserved in human PZP and marmoset A2ML1. These proteins contain multiple sites that are cleaved by proteases involving proline-endopeptidase. Systemic regulation of these A2M family proteins may be important in animals with invasive placenta.

An Oral Rinse Active Matrix Metalloproteinase-8 Point-of-Care Immunotest May Be Less Accurate in Patients with Crohn's Disease

The diagnostic accuracy of point-of-care (PoC) applications may be compromised in individuals with additional inflammatory conditions. This cross-sectional study examined the performance of a commercial oral rinse active matrix metalloproteinase-8 (aMMP-8) PoC immunotest in individuals with (n = 47) and without Crohn's disease (CD) (n = 41). Oral rinse collected from the participants was analyzed by the PoC immunotest. Molecular forms and fragments of salivary MMP-8 were detected by western immunoblotting. The sensitivity of the immunotest for periodontitis was 60.0% in the CD group and 90.0% in the control group. The respective specificity was 75.0% and 80.0%. In both groups, clinical diagnosis of periodontitis exhibited a significant association with the immunotest results, however, the odds ratio (OR) was more than ten-fold in controls (OR 54.3, 95% CI: 3.1-953, p = 0.006) in comparison to CD patients (OR 5.2, 95% CI: 1.3-21.6, p = 0.022). According to Western immunoblot results, the immunotest MMP-8 positivity was not related to elevated levels of molecular forms and fragments of MMP-8 in the CD group, as in the control group. The diagnostic accuracy of the aMMP-8 PoC oral rinse immunotest is reduced in CD patients, which may be related to lower levels or undetectable complexes.