FGL2 regulates IKK/NF-κB signaling in intestinal epithelial cells and lamina propria dendritic cells to attenuate dextran sulfate sodium-induced colitis

Aegeline attenuates TNBS-induced colitis by suppressing the NFƙB-mediated NLRP3 inflammasome pathway in mice

A chronic inflammatory condition of the intestine, ulcerative colitis (UC), is challenging to successfully manage once diagnosed. Currently, available medical therapies for UC exhibit minimal efficacy with unacceptable side effects, while inventive biological agents are expensive and yet not well accepted by patients. Discovering more effective and safer treatments to treat UC is therefore essential. One of the primary alkaloids found in Aegle marmelos, aegeline, has anti-inflammatory and antioxidant properties as well as being able to suppress several pro-inflammatory cytokines responsible for inflammation. The study aimed to investigate the effectiveness of aegeline in alleviating 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis through the NFƙB-mediated NLRP3 inflammasome pathway. Mice were randomly allocated into six groups, Normal control (NC), Model control (MC-TNBS, 2,4,6-trinitrobenzene sulfonic acid), STD (TNBS + sulfasalazine 100 mg/kg), AG1, AG2, and AG3 (TNBS + aegeline 5, 10, 20 mg/kg) respectively. Physical parameters such as a change in body weight, stool consistency, rectal bleeding, colon length, myeloperoxidase (MPO) levels and nitric oxide (NO) levels, and disease activity index (DAI) were assessed and supporting gene expression studies of various pro-inflammatory cytokines and enzymes were evaluated and histopathological changes observed. Administration of aegeline (10, 20 mg/kg) was found to be effective in colon protection by lowering the disease activity score and myeloperoxidase level and improving other physical parameters. Aegeline in high dose significantly downregulated the gene expression of NFƙB, iNOS, COX-2, NLRP3, IL-1β, and IL-18, conferring great anti-inflammatory potential. Suggestive of the findings, aegeline reduced the damage to the colon by downregulating transcriptional genes and enzymes leading to inflammation and mitigated TNBS-induced colitis probably through the NFƙB-mediated NLRP3 inflammasome pathway.

Aspergillus cristatus attenuates DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating short-chain fatty acid and inhibiting MAPK signaling pathways

BACKGROUND

Probiotics are regarded as a promising strategy for relieving colitis caused by dextran sulfate sodium (DSS). One of the dominant probiotic fungi in Fuzhuan brick tea is identified as Aspergillus cristatus, but whether it can effectively improve colitis remains poorly understood. Here, the improving effect of A. cristatus on colitis was investigated.

RESULTS

Our results showed that A. cristatus intervention prominently alleviated gut damage as evidenced by the inhibition of shortened colon length, goblet cell depletion, and histological injury. Mechanistically, after administration with low concentrations of A. cristatus H-1 and A. cristatus S-6, the expression of interleukin-6, tumor necrosis factor-α, interleukin-1β, nitric oxide, and malondialdehyde were significantly downregulated, and the content of glutathione, catalase, interleukin-10, immunoglobulin G, claudin-1, occludin, and zonula occludens-1 were effectively upregulated. More importantly, live A. cristatus supplementation lightened DSS-induced gut barrier damage by suppressing activation of the mitogen-activated protein kinase (MAPK) signaling pathway, increasing the synthesis of short-chain fatty acids (SCFAs) and stimulating the increase in peroxisome proliferator-activated receptor γ expression.

CONCLUSION

Together, A. cristatus can attenuate DSS-induced intestinal barrier damage through reducing the oxidative stress, regulating SCFA and inhibiting MAPK signaling pathways (P38/JNK/ERK). Our findings indicate that A. cristatus replenishment has potential as a new probiotic fungi to reduce DSS-induced colitis. © 2022 Society of Chemical Industry.

Fibrinogen-like protein 2 in inflammatory diseases: A future therapeutic target

Fibrinogen-like protein 2 (FGL2), a member of the fibrinogen family, exists as a membrane-bound protein with immune-associated coagulation activity and a soluble form possessing immunosuppressive functions. The immunomodulatory role of FGL2 is evident in fibrin deposition-associated inflammatory diseases and cancer, suggesting that FGL2 expression could be exploited as a disease biomarker and a therapeutic target. Recently, in vitro studies and knockout and transgenic animal FGL2 models have been used by us and others to reveal the involvement of FGL2 in the pathogenesis of various inflammatory diseases. This review summarizes our current knowledge of the immunomodulatory role of FGL2 in inflammatory diseases and examines the role of FGL2 as a potential therapeutic target.

A homozygous truncating mutation of FGL2 is associated with immune dysregulation

BACKGROUND

The type II transmembrane protein fibrinogen-like protein 2 (FGL2) plays critical roles in hemostasis and immune regulation. The C-terminal immunoregulatory domain of FGL2 can be secreted and is a mediator of regulatory T (Treg) cell suppression. Fgl2^-/- mice develop autoantibodies and glomerulonephritis and have impaired Treg cell function.

OBJECTIVE

Our aim was to identify the genetic underpinning and immune function in a patient with childhood onset of leukocytoclastic vasculitis, systemic inflammation, and autoantibodies.

METHODS

Whole-exome sequencing was performed on patient genomic DNA. FGL2 protein expression was examined in HEK293 transfected cells by immunoblotting and in PBMCs by flow cytometry. T follicular helper cells and Treg cells were examined by flow cytometry. Treg cell suppression of T-cell proliferation was assessed in vitro.

RESULTS

The patient had a homozygous mutation in FGL2 (c.614_617del:p.V205fs), which led to the expression of a truncated FGL2 protein that preserves the N-terminal domain but lacks the C-terminal immunoregulatory domain. The patient had an increased percentage of circulating T follicular helper and Treg cells. The patient's Treg cells had impaired in vitro suppressive ability that was rescued by the addition of full-length FGL2. Unlike full-length FGL2, the truncated FGL2^V205fs mutant failed to suppress T-cell proliferation.

CONCLUSIONS

We identified a homozygous mutation in FGL2 in a patient with immune dysregulation and impaired Treg cell function. Soluble FGL2 rescued the Treg cell defect, suggesting that it may provide a useful therapy for the patient.

The Experimental Exploration of TCM Theory "Treating the Same Disease with Different Approaches" on an Ulcerative Colitis Model

There is a relationship between lung injury and ulcerative colitis. Currently, traditional Chinese medicine (Huangqi Jiegeng (HQJGD) and Huangqi Huanglian decoctions (HQHLD)) is commonly used for UC-related lung injury; however, the mechanisms of these drugs remain unclear. In this study, UC models were established with the mucous membrane of colon allergize combined with TNBS-alcohol enteroclysis for 4 weeks. The pathological changes in the lung, intestine, liver, and kidney were observed; cytokines, chemokines, and adhesion molecules in lung tissue were detected in order to explore the immunological mechanism of UC-related lung injury and the intervention mechanism of traditional Chinese medicine in treating the lung and intestine in the immune-TNBS-ethanol rat model. Histology examinations demonstrated evident pathological changes in the lungs and intestines of the model groups. Furthermore, all groups treated with TCMs demonstrated reduced expressions of toll-like receptor 4, nuclear factor kappa-B, and macrophage migration inhibitory factor. Additionally, radioimmunoassay and immunohistochemistry showed tumor necrosis factor-α, interleukin-6, and 8 expression downregulation. The results showed that HQJGD and HQHLD could alleviate pulmonary inflammation in UC-related lung injury by obviously improving the pathology and fibrosis of the lung, inhibiting the positive feedback loop of MIF/NF-κB, and reducing lymphocyte homing to bronchial mucosa. This model revealed the immune mechanism of UC-related lung injury and the intervention mechanism of the Chinese medicine, which provided the rationale for treating ulcerative colitis clinically, so as to demonstrate the theory of “the lung and the large intestine being interior-exteriorly related” and “treating the same disease with different approaches.”

Diosmetin has therapeutic efficacy in colitis regulating gut microbiota, inflammation, and oxidative stress via the circ-Sirt1/Sirt1 axis

Diosmetin (3',5,7 -trihydroxy-4'-methoxy flavone) is a natural flavonoid compound in the citrus species, it exhibits a variety of pharmacological activities, but little is known of its effects on colitis. In this study we evaluated the therapeutic effects of diosmetin on mouse models of chronic and acute colitis. Chronic colitis was induced in mice by drinking water containing 3% dextran sulfate sodium (DSS) from D0 to D8, followed by administration of diosmetin (25, 50 mg · kg^-1 · d^-1) for another 8 days. Acute colitis was induced by drinking water containing 5% DSS from D0 to D7, the mice concomitantly received diosmetin (25, 50 mg · kg^-1 · d^-1) from D1 to D7. During the experiments, body weight and disease activity index (DAI) were assessed daily. After the mice were sacrificed, colon tissue and feces samples were collected, and colon length was measured. We showed that in both models, diosmetin administration significantly decreased DAI score and ameliorated microscopic colon tissue damage; increased the expression of tight junction proteins (occludin, claudin-1, and zonula occludens-1), and reduced the secretion of proinflammatory cytokines IL-1β, IL-6, TNF-α, and Cox-2 in colon tissue. We found that diosmetin administration remarkably inhibited colon oxidative damage by adjusting the levels of intracellular and mitochondrial reactive oxygen species, GSH-Px, SOD, MDA and GSH in colon tissue. The protection of diosmetin against intestinal epithelial barrier damage and oxidative stress were also observed in LPS-treated Caco-2 and IEC-6 cells in vitro. Furthermore, we demonstrated that diosmetin markedly increased the expression of Nrf2 and HO-1 and reduced the ratio of acetylated NF-κB and NF-κB by activating the circ-Sirt1/Sirt1 axis, which inhibited oxidative stress and inflammation in vivo and in vitro. Diosmetin reversed the effects of si-circSirt1 and si-Sirt1 in LPS-treated Caco-2 and IEC-6 cells. When the gut microbiota was analyzed in the mouse model of colitis, we found that diosmetin administration modulated the abundance of Bacteroidetes, Actinobacteria, Cyanobacteria and Firmicutes, which were crucial for inflammatory bowel disease. Our results have linked colitis to the circ-Sirt1/Sirt1 signaling pathway, which is activated by diosmetin. The results imply that diosmetin may be a novel candidate to alleviate DSS-induced colitis and can be a lead compound for future optimization and modification.

Gentianella acuta mitigates cardiovascular damage and inflammation in diet-induced hypercholesterolaemic rats

Gentianella acuta (G. acuta) has been widely used as a traditional medicine by Chinese Mongolian populations for the treatment of heart diseases and has also been tested in modern pharmacological experiments. However, the effects of G. acuta on cardiovascular damage and inflammation under conditions of hypercholesterolaemia remain unclear. The present study investigated the effects and mechanisms of the water extract of G. acuta on cardiovascular damage and inflammation caused by a high-cholesterol diet. Male Sprague-Dawley rats were fed a high-cholesterol diet for 4 weeks to establish the hypercholesterolaemia rat model, and they were administered physiological saline or 1.2 g/kg of G. acuta by gavage starting from the 15th day. After the last administration, the blood, heart and thoracic aorta samples were collected and examined. It was revealed that G. acuta treatment could ameliorate cardiomyocyte disorder and thoracic aortic vessel wall damage, reduce serum lipid levels and inflammatory factors and improve heart function. Compared with the Model group, the serum levels of triglycerides, total cholesterol, low-density lipoprotein and tumour necrosis factor-α were decreased, and the high-density lipoprotein and interleukin-10 levels were increased in the Model-G group. Moreover, in both the heart and thoracic aorta, G. acuta reduced the expression and phosphorylation of inhibitor of nuclear factor kappa-B kinase β (IKKβ), inhibitor of NF-κB-α (IκBα) and p-nuclear factor kappa-B (NF-κB). Therefore, G. acuta may exert an inhibitory effect on the IKK/IκB/NF-κB signalling pathway to protect the heart and thoracic aorta in hypercholesterolaemic rats.

Muscle transcriptional networks linked to resistance exercise training hypertrophic response heterogeneity

The skeletal muscle hypertrophic response to resistance exercise training (RT) is highly variable across individuals. The molecular underpinnings of this heterogeneity are unclear. This study investigated transcriptional networks linked to RT-induced muscle hypertrophy, classified as 1) predictive of hypertrophy, 2) responsive to RT independent of muscle hypertrophy, or 3) plastic with hypertrophy. Older adults (n = 31, 18 F/13 M, 70 ± 4 yr) underwent 14-wk RT (3 days/wk, alternating high-low-high intensity). Muscle hypertrophy was assessed by pre- to post-RT change in mid-thigh muscle cross-sectional area (CSA) [computed tomography (CT), primary outcome] and thigh lean mass [dual-energy X-ray absorptiometry (DXA), secondary outcome]. Transcriptome-wide poly-A RNA-seq was performed on vastus lateralis tissue collected pre- (n = 31) and post-RT (n = 22). Prediction networks (using only baseline RNA-seq) were identified by weighted gene correlation network analysis (WGCNA). To identify Plasticity networks, WGCNA change indices for paired samples were calculated and correlated to changes in muscle size outcomes. Pathway-level information extractor (PLIER) was applied to identify Response networks and link genes to biological annotation. Prediction networks (n = 6) confirmed transcripts previously connected to resistance/aerobic training adaptations in the MetaMEx database while revealing novel member genes that should fuel future research to understand the influence of baseline muscle gene expression on hypertrophy. Response networks (n = 6) indicated RT-induced increase in aerobic metabolism and reduced expression of genes associated with spliceosome biology and type-I myofibers. A single exploratory Plasticity network was identified. Findings support that interindividual differences in baseline gene expression may contribute more than RT-induced changes in gene networks to muscle hypertrophic response heterogeneity. Code/Data: https://github.com/kallavin/MASTERS_manuscript/tree/master.

The role of Fibrinogen-like proteins in Cancer

Fibrinogen-associated protein (FREP) family is a family of proteins with a fibrin domain at the carboxyl terminus. Recent investigations illustrated that two members of FREP family, fibrinogen-like protein-1 (FGL1) and fibrinogen-like protein-2 (FGL2), play crucial roles in cancer by regulating the proliferation, invasion, and migration of tumor cells, or regulating the functions of immune cells in tumor microenvironment. Meanwhile, they are potential targets for medical intervention of tumor development. In this review, we discussed the structure, and the roles of FGL1 and FGL2 in tumors, especially the roles in regulating immune cell functions.

TL1A primed dendritic cells activation exacerbated chronic murine colitis

AIMS

Tumor necrosis factor-like ligand 1A (TL1A) has been proved to activate adaptive immunity in inflammatory bowel disease (IBD). However, its role in the regulation of intestinal dendritic cells (DCs) has not been fully characterized. This study aims to investigate the modulation of TL1A in DCs activation in murine colitis.

MATERIALS AND METHODS

Myeloid TL1A-Transgenic C57BL/6 mice and wild-type (WT) mice were administrated with dextran sulfate sodium (DSS) to explore the effects of TL1A in murine colitis. Bone marrow-derived DCs (BMDCs) were isolated to detect the ability of antigen phagocytosis and presentation. The expression of nuclear factor-κB (NF-κB) pathway and chemokines receptors (CCRs) was assessed by real-time PCR and Western blot.

KEY FINDINGS

Myeloid cells with constitutive TL1A expression developed worsened murine colitis with exacerbated T_H1/T_H17 cytokine responses. Intestinal DCs from TL1A transgenic mice expressed high levels of costimulatory molecules (CD80 and CD86) with increased pro-inflammatory cytokines of IL-1β, TNF-α and IL-12/23 p40. Mechanistic studies showed that TL1A enhanced the phagocytotic ability of BMDCs. Moreover, TL1A enhanced the capacity of antigen process and presentation in BMDCs. Besides, TL1A induced the phosphorylation of NF-κB(p65) and IκBα. Meanwhile, higher expression of CCR2, CCR5, CCR7, and CX3CR1 was observed both in vivo and in vitro.

SIGNIFICANCE

TL1A exacerbated DSS-induced chronic experimental colitis, probably through activation and migration of dendritic cells, and therefore increasing the secretion of pro-inflammatory cytokines.

A Ganoderma atrum polysaccharide alleviated DSS-induced ulcerative colitis by protecting the apoptosis/autophagy-regulated physical barrier and the DC-related immune barrier

Polysaccharides are one of the main active substances in Ganoderma atrum (G. atrum). The purpose of this study was to explore the protective effect of a G. atrum polysaccharide (PSG-1) on DSS-induced colitis and the underlying mechanism. The results showed that PSG-1 could maintain the integrity of the intestinal structure by promoting the expression of goblet cells and levels of tight junction proteins in the colon of DSS-induced colitis mice. Furthermore, PSG-1 relieved the inhibition of Bcl-2 and the overexpression of caspase-3 and caspase-9 caused by DSS. Simultaneously, PSG-1 restored the expression of Atg5, Atg7 and beclin-1 and inhibited the p-akt and p-mTOR levels, suggesting that PSG-1 promoted autophagy via the Akt/mTOR pathway. Moreover, PSG-1 inhibited the content of DCs in the colon and modulated the expression of IL-10 in DCs. In conclusion, PSG-1 alleviated DSS-induced ulcerative colitis by protecting the apoptosis/autophagy-regulated physical barrier and the DC-related immune barrier.

Biomarkers of Inflammation in Inflammatory Bowel Disease: How Long before Abandoning Single-Marker Approaches?

BACKGROUND

Inflammatory bowel disease (IBD) is a chronically relapsing disease with a continuous need for proactive monitoring to decide appropriate treatments and follow-up strategies. To date, gastrointestinal endoscopy with histologic examination of biopsies and contrast-enhanced imaging are mandatory techniques for the diagnosis and the activity assessment of IBD.

SUMMARY

In recent decades, many research efforts in the IBD field have been placed on finding non-invasive and reliable biomarkers of disease burden that can be easily tested in body fluids without impacting the quality of life of patients. Unfortunately, the ideal biomarker is yet to be discovered and recent studies have investigated the possibility to increase the accuracy of such measurements by combining different markers. In this review, we provide an update about the current knowledge on biomarkers of intestinal inflammation in IBD, focussing on disease diagnosis, correlation with endoscopic findings, and prediction of relapse. We also summarize composite scores of clinical and laboratory markers that have been recently proposed in various scenarios of disease activity. Key Messages: To date, only C-reactive protein and faecal calprotectin can be considered reliable markers of disease activity with demonstrated utility in IBD management. The combination of different parameters has recently shown higher accuracy and might substitute single-marker approaches in the future of research and clinical practice.