Effects of Anti-Cytokine Antibodies on Gut Barrier Function

Schisandra chinensis lignans regulate and cooperate with endogenous cannabinoid systems to ameliorate intestinal barrier injury associated with depression

BACKGROUND

Schisandra chinensis lignan (SCL), a major active component of the traditional functional Chinese medicine Schisandra chinensis, has been reported to have antidepressant effects. Its mechanisms include alleviating intestinal barrier injury (IBI) by resolving intestinal microflora, anti-inflammation, and neuroprotection. SCL also regulates endogenous cannabinoid system, and it is closely related to the onset and development of depression.

PURPOSE

We investigated a new treatment strategy for depression, i.e., alleviating IBI by regulating the endogenous cannabinoid system for antidepressant effects, as well as conducted in-depth research to explore the specific mechanism.

METHODS

Behavioral analysis was conducted to detect the occurrence of depressive-like behavior in C57BL/6 mice. We used hematoxylin-eosin staining, periodic acid-Schiff staining, and immunofluorescence to evaluate IBI. Network pharmacology and Western blotting (WB) were used to predict and confirm that the amelioration effect of SCL was associated with anti-inflammation and anti-apoptosis. Combined with the levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG), we conducted the Pearson analysis between the AEA, 2-AG levels and the major targets identified and validated by network pharmacology and WB. Subsequently, URB-597, a fatty acid amide hydrolase (FAAH) antagonist with an AEA hydrolase-inhibiting effect, was administered to the mice, and behavioral analysis and apoptotic proteins were verified. Plasma endocannabinoid levels after URB-597 supplementation were measured via 6470 Triple Quadrupole LC/MS. Finally, the cannabinoid receptor type 2 (CB2R) antagonist AM630 was administered to mice, and immunofluorescence and WB were performed to assess the proteins of IBI and anti-inflammation.

RESULTS

The study demonstrated that SCL alleviated depressive-like behaviours and ameliorated IBI. Network pharmacology and WB confirmed that the improvement of IBI was related to the anti-inflammatory and anti-apoptotic pathways. Pearson results showed that AEA levels were positively correlated with inflammation and apoptosis, with a greater contribution to apoptosis. In-depth studies validated that the URB-597 administration reversed the positive effects of SCL on depressive-like behavior and anti-apoptosis. Similarly, URB-597 counteracted AEA levels reduced by SCL and decreased 2-AG levels. Furthermore, AM630 supplementation antagonized SCL's effect of improving IBI by reactivating the MAPK/NF-κB inflammation pathway.

CONCLUSION

Overall, SCL, in collaboration with the endogenous cannabinoid system regulated by SCL, alleviates depression associated IBI. The specific mechanism involes SCL decreasing AEA levels to inhibit colon tissue cell apoptosis by up-regulating FAAH. Simultaneously, it directly triggers CB2R to reduce inflammation responses, further alleviating IBI.

Neurodegenerative and Neurodevelopmental Diseases and the Gut-Brain Axis: The Potential of Therapeutic Targeting of the Microbiome

The human gut microbiome contains the largest number of bacteria in the body and has the potential to greatly influence metabolism, not only locally but also systemically. There is an established link between a healthy, balanced, and diverse microbiome and overall health. When the gut microbiome becomes unbalanced (dysbiosis) through dietary changes, medication use, lifestyle choices, environmental factors, and ageing, this has a profound effect on our health and is linked to many diseases, including lifestyle diseases, metabolic diseases, inflammatory diseases, and neurological diseases. While this link in humans is largely an association of dysbiosis with disease, in animal models, a causative link can be demonstrated. The link between the gut and the brain is particularly important in maintaining brain health, with a strong association between dysbiosis in the gut and neurodegenerative and neurodevelopmental diseases. This link suggests not only that the gut microbiota composition can be used to make an early diagnosis of neurodegenerative and neurodevelopmental diseases but also that modifying the gut microbiome to influence the microbiome-gut-brain axis might present a therapeutic target for diseases that have proved intractable, with the aim of altering the trajectory of neurodegenerative and neurodevelopmental diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, autism spectrum disorder, and attention-deficit hyperactivity disorder, among others. There is also a microbiome-gut-brain link to other potentially reversible neurological diseases, such as migraine, post-operative cognitive dysfunction, and long COVID, which might be considered models of therapy for neurodegenerative disease. The role of traditional methods in altering the microbiome, as well as newer, more novel treatments such as faecal microbiome transplants and photobiomodulation, are discussed.

Role of Brain-Gut-Microbiota Axis in Depression: Emerging Therapeutic Avenues

The human gut microbiota plays a significant role in the pathophysiology of central nervous system-related diseases. Recent studies suggest correlations between the altered gut microbiota and major depressive disorder (MDD). It is proposed that normalization of the gut microbiota alleviates MDD. The imbalance of brain-gut-microbiota axis also results in dysregulation of the hypothalamicpituitary- adrenal (HPA) axis. This imbalance has a crucial role in the pathogenesis of depression. Treatment strategies with certain antibiotics lead to the depletion of useful microbes and thereby induce depression like effects in subjects. Microbiota is also involved in the synthesis of various neurotransmitters (NTs) like 5-hydroxy tryptamine (5-HT; serotonin), norepinephrine (NE) and dopamine (DA). In addition to NTs, the gut microbiota also has an influence on brain derived neurotrophic factor (BDNF) levels. Recent research findings have exhibited that transfer of stress prone microbiota in mice is also responsible for depression and anxiety-like behaviour in animals. The use of probiotics, prebiotics, synbiotics and proper diet have shown beneficial effects in the regulation of depression pathogenesis. Moreover, transplantation of fecal microbiota from depressed individuals to normal subjects also induces depression-like symptoms. With the precedence of limited therapeutic benefits from monoamine targeting drugs, the regulation of brain-gut microbiota is emerging as a new treatment modality for MDDs. In this review, we elaborate on the significance of brain-gut-microbiota axis in the progression of MDD, particularly focusing on the modulation of the gut microbiota as a mode of treating MDD.

The Basophil IL-18 Receptor Precisely Regulates the Host Immune Response and Malaria-Induced Intestinal Permeability and Alters Parasite Transmission to Mosquitoes without Effect on Gametocytemia

We have recently demonstrated that basophils are protective against intestinal permeability during malaria and contribute to reduced parasite transmission to mosquitoes. Given that IL-18 is an early cytokine/alarmin in malaria and has been shown to activate basophils, we sought to determine the role of the basophil IL-18R in this protective phenotype. To address this, we infected control [IL18r ^flox/flox or basoIL-18R (+)] mice and mice with basophils lacking the IL-18R [IL18r ^flox/flox × Basoph8 or basoIL-18R (-)] with Plasmodium yoelii yoelii 17XNL, a nonlethal strain of mouse malaria. Postinfection (PI), intestinal permeability, ileal mastocytosis, bacteremia, and levels of ileal and plasma cytokines and chemokines were measured through 10 d PI. BasoIL-18R (-) mice exhibited greater intestinal permeability relative to basoIL-18R (+) mice, along with increased plasma levels of proinflammatory cytokines at a single time point PI, day 4 PI, a pattern not observed in basoIL-18R (+) mice. Surprisingly, mosquitoes fed on basoIL-18R (-) mice became infected less frequently than mosquitoes fed on basoIL-18R (+) mice, with no difference in gametocytemia, a pattern that was distinct from that observed previously with basophil-depleted mice. These findings suggest that early basophil-dependent protection of the intestinal barrier in malaria is mediated by IL-18, and that basophil IL-18R-dependent signaling differentially regulates the inflammatory response to infection and parasite transmission.

Network-based response module comprised of gene expression biomarkers predicts response to infliximab at treatment initiation in ulcerative colitis

This cross-cohort study aimed to (1) determine a network-based molecular signature that predicts the likelihood of inadequate response to the tumor necrosis factor-ɑ inhibitor (TNFi) therapy, infliximab, in ulcerative colitis (UC) patients, and (2) address biomarker irreproducibility across different cohort studies. Whole-transcriptome microarray data were derived from biopsies of affected colon tissue from 2 cohorts of infliximab-treated UC patients (training N = 24 and validation N = 22). Response was defined as endoscopic and histologic healing at 4-6 weeks and 8 weeks, respectively. From the training cohort, genes with RNA expression that significantly correlated with clinical response outcomes were mapped onto the Human Interactome network map of protein-protein interactions to identify a largest connected component (LCC) of proteins indicative of infliximab response status in UC. Expression levels of transcripts within the LCC were fed into a probabilistic neural network model to generate a classifier that predicts inadequate response to infliximab. A classifier predictive of inadequate response to infliximab was generated and tested in a cross-cohort, blinded fashion; the AUC was 0.83 and inadequate response was predicted with a 100% positive predictive value and 64% sensitivity. Genes separately identified from the 2 cohorts that correlated with response to infliximab appeared distinct but mapped onto the same network region of the Human Interactome, reflecting a common underlying biology of response among UC patients. Cross-cohort validation of a classifier predictive of infliximab response status in UC patients indicates that a molecular signature of non-response to TNFi therapies is present in patients' baseline gene expression data. The goal is to develop a diagnostic test that predicts which patients will have an inadequate response to targeted therapies and define new targets and pathways for therapeutic development.

Bacterial Species Associated With Human Inflammatory Bowel Disease and Their Pathogenic Mechanisms

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with unknown etiology. The pathogenesis of IBD results from immune responses to microbes in the gastrointestinal tract. Various bacterial species that are associated with human IBD have been identified. However, the microbes that trigger the development of human IBD are still not clear. Here we review bacterial species that are associated with human IBD and their pathogenic mechanisms to provide an updated broad understanding of this research field. IBD is an inflammatory syndrome rather than a single disease. We propose a three-stage pathogenesis model to illustrate the roles of different IBD-associated bacterial species and gut commensal bacteria in the development of human IBD. Finally, we recommend microbe-targeted therapeutic strategies based on the three-stage pathogenesis model.

RETRACTED: Network-based response module comprised of gene expression biomarkers predicts response to infliximab at treatment initiation in ulcerative colitis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the authors after consulting with the Editors. During a follow-up study, the authors regretfully discovered that the microarray probe-to-gene mapping was incorrect. Although the methodology and primary findings remain the same, the identity of the biomarker genes are incorrect as a result of this honest mistake. The extent of the changes to correct this information necessitated the publication of a corrected version of this article: https://doi.org/10.1016/j.trsl.2022.03.006.

Antiinflammatory phytochemicals against virus-induced hyperinflammatory responses: Scope, rationale, application, and limitations

Uncontrolled inflammatory responses or cytokine storm associated with viral infections results in deleterious consequences such as vascular leakage, severe hemorrhage, shock, immune paralysis, multi-organ failure, and even death. With the emerging new viral infections and lack of effective prophylactic vaccines, evidence-based complementary strategies that limit viral infection-mediated hyperinflammatory responses could be a promising approach to limit host tissue injury. The present review emphasizes the potentials of antiinflammatory phytochemicals in limiting hyperinflammatory injury caused by viral infections. The predominant phytochemicals along with their mechanism in limiting hyperimmune and pro-inflammatory responses under viral infection have been reviewed comprehensively. How certain phytochemicals can be effective in limiting hyper-inflammatory response indirectly by favorably modulating gut microbiota and maintaining a functional intestinal barrier has also been presented. Finally, we have discussed improved systemic bioavailability of phytochemicals, efficient delivery strategies, and safety measures for effective antiinflammatory phytotherapies, in addition to emphasizing the requirement of tightly controlled clinical studies to establish the antiinflammatory efficacy of the phytochemicals. Collectively, the review provides a scooping overview on the potentials of bioactive phytochemicals to mitigate pro-inflammatory injury associated with viral infections.

Whole and refined grains change behavior and reduce brain derived neurotrophic factor and neurotrophin-3 in rats

In most of the world, wheat is one of the main staple foods, and is also widely used in livestock feed. In the current study, we investigated the effects of wheat grain consumption on the rat behavior and neurogenesis markers. Thirty male rats were divided into three equal groups (n = 10). Group 1 was the control group fed with chow diet (Carbohydrates 63%, fat 13% and protein 24%), the Group 2 rats were fed with whole grains and the Group 3 rats were fed with refined grains. After 12 weeks, we measured the hippocampal and prefrontal cortical brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), 5-hydroxytryptamine, dopamine, norepinephrine, malondialdehyde (MDA) and reduced glutathione (GSH) levels. Also, we evaluated the rat behavior by forced swimming test (FST) and elevated plus maze (EPM) test. Additionally, we measured serum level of glucose, lipid profile, insulin and cortisol. Weight gain at the end of the study was measured in each group. The rats on a diet of whole and refined grains had low BDNF, NT-3, norepinephrine, dopamine and serotonin significantly (p < .01) in both the hippocampus and prefrontal cortex as compared to control rats. Moreover, the MDA increased significantly with significant reduction in GSH versus the control rats. Moreover, in response to grain consumption, the performance in FST showed a significant (p < .01) shortage in the latency of the attempts to escape as well as a significant prolongation (p < .01) in behavioral immobility as compared to control rats with significant (p < .05) prolongation in time spent in closed arm in EPM. An exclusive diet of either whole or refined grain in a rat model induced anxiety and depressive behaviors and negatively affected the BDNF and NT-3 and modulated the level of the neurotransmitters with significant shift in their behavior. PRACTICAL APPLICATIONS: Grains are considered the major caloric source all over the world that may predispose to the development of chronic diseases. In this research, we evaluated the role of grains in modulating the rate of production of neurogenic factors in rats.

Targeting gut barrier dysfunction with phytotherapies: Effective strategy against chronic diseases

The intestinal epithelial layer serves as a physical and functional barrier between the microbe-rich lumen and immunologically active submucosa; it prevents systemic translocation of microbial pyrogenic products (e.g. endotoxin) that elicits immune activation upon translocation to the systemic circulation. Loss of barrier function has been associated with chronic 'low-grade' systemic inflammation which underlies pathogenesis of numerous no-communicable chronic inflammatory disease. Thus, targeting gut barrier dysfunction is an effective strategy for the prevention and/or treatment of chronic disease. This review intends to emphasize on the beneficial effects of herbal formulations, phytochemicals and traditional phytomedicines in attenuating intestinal barrier dysfunction. It also aims to provide a comprehensive understanding of intestinal-level events leading to a 'leaky-gut' and systemic complications mediated by endotoxemia. Additionally, a variety of detectable markers and diagnostic criteria utilized to evaluate barrier improving capacities of experimental therapeutics has been discussed. Collectively, this review provides rationale for targeting gut barrier dysfunction by phytotherapies for treating chronic diseases that are associated with endotoxemia-induced systemic inflammation.