Preventative delivery of IL-35 by Lactococcus lactis ameliorates DSS-induced colitis in mice. Appl Microbiol Biotechnol. 2019;103:7931-7941. [PMID: 31456001 DOI: 10.1007/s00253-019-10094-9]

Gut microbiota derived indole-3-acetic acid ameliorates precancerous inflammatory intestinal milieu to inhibit tumorigenesis through IL-35

BACKGROUND

Gut microbiota can significantly alter the risk or progression of cancer by maintaining gut immune system homeostasis. However, the exact mechanism by which the gut microbiota and its metabolites influence colorectal tumorigenesis is unclear.

METHODS

The roles of tryptophan metabolite indole-3-acetic acid (IAA) in inflammation and tumor development were investigated in dextran sodium sulfate (DSS) and azoxymethane (AOM)-DSS mouse models with or without IAA supplementation and with or without Lactobacillus reuteri-produced IAA. Pregnane X receptor (PXR) knockout (KO) mice and aryl hydrocarbon receptor KO mice were used to explore the mechanism by which IAA regulates interleukin (IL)-35 expression. IL-35+ immune cells were stimulated in vitro and analyzed by flow cytometry. Additionally, metabolites were analyzed by liquid chromatography-mass spectrometry.

RESULTS

We found that IAA, a metabolite of tryptophan produced in the gut by L. reuteri, can inhibit the development of colitis by inducing IL-35 expression in immunosuppressant cells. HuREG3αIECtg mice had high levels of intestinal microbiota-derived IAA, and these mice were resistant to AOM-DSS-induced cancer. Patients with colorectal cancer also had low peripheral blood levels of IAA. Further studies revealed that IAA-producing L. reuteri alleviated colitis symptoms and inhibited colon tumors by inducing macrophages, T cells, and B cells to produce IL-35. Finally, PXR KO completely abolished the effects of IAA on immune cells.

CONCLUSION

We demonstrate that gut microbiota-derived IAA can improve the precancerous colon inflammatory environment through IL-35, thereby inhibiting tumorigenesis, suggesting that IAA may be a preventive factor for colitis-related cancers.

Lactobacillus helveticus LZ-R-5 Ameliorates DSS-Induced Colitis in Mice by Modulating Gut Microbiota and Enhancing Intestinal Barrier Function

Lactobacillus helveticus LZ-R-5 (R-5), a strain with high epithelial adhesion and bioactive exopolysaccharide production, was isolated from Tibetan kefir grains. This study investigated its potential to alleviate intestinal inflammation using a DSS-induced colitis model in BALB/c mice. We integrated microbial diversity and serological analyses to assess changes in gut flora and cytokines following the R-5 treatment. Pathological assessments showed that R-5 reduced crypt distortion in the proximal colon and mitigated hepatic immune challenges by enhancing gut barrier function. The increased relative expression of TGF-β1 and the downregulation of NLRP3-related inflammatory factors were conducive to preventing organ damage in the thymus and spleen of mice with colitis. Additionally, R-5 stimulated GPR43 expression and improved epithelial nutrition, promoting mucin production to prevent enterotoxin leakage. It also modulated the gut microbiota by suppressing Bacteroides and Erysipelatoclostridium, leading to a microbiota composition more akin to that of normal flora.

From probiotic chassis to modification strategies, control and improvement of genetically engineered probiotics for inflammatory bowel disease

With the rising morbidity of inflammatory bowel disease (IBD) year by year, conventional therapeutic drugs with systemic side effects are no longer able to meet the requirements of patients. Probiotics can improve gut microbiota, enhance intestinal barrier function, and regulate mucosal immunity, making them a potential complementary or alternative therapy for IBD. To compensate for the low potency of probiotics, genetic engineering technology has been widely used to improve their therapeutic function. In this review, we systematically summarize the genetically engineered probiotics used for IBD treatment, including probiotic chassis, genetic modification strategies, methods for controlling probiotics, and means of improving efficacy. Finally, we provide prospects on how genetically engineered probiotics can be extended to clinical applications.

Interleukin-35 alleviates neuropathic pain and induces an anti-inflammatory shift in spinal microglia in nerve-injured male mice

Immune cells are critical in promoting neuroinflammation and neuropathic pain and in facilitating pain resolution, depending on their inflammatory and immunoregulatory cytokine response. Interleukin (IL)-35, secreted by regulatory immune cells, is a member of the IL-12 family with a potent immunosuppressive function. In this study, we investigated the effects of IL-35 on pain behaviors, spinal microglia phenotype following peripheral nerve injury, and in vitro microglial cultures in male and female mice. Intrathecal recombinant IL-35 treatment alleviated mechanical pain hypersensitivity prominently in male mice, with only a modest effect in female mice after sciatic nerve chronic constriction injury (CCI). IL-35 treatment resulted in sex-specific microglial changes following CCI, reducing inflammatory microglial markers and upregulating anti-inflammatory markers in male mice. Spatial transcriptomic analysis revealed that IL-35 suppressed microglial complement activation in the superficial dorsal horn in male mice after CCI. Moreover, in vitro studies showed that IL-35 treatment of cultured inflammatory microglia mitigated their hypertrophied morphology, increased their cell motility, and decreased their phagocytic activity, indicating a phenotypic shift towards homeostatic microglia. Further, IL-35 altered microglial cytokines/chemokines in vitro, suppressing the release of IL-9 and monocyte-chemoattractant protein-1 and increasing IL-10 in the supernatant of male microglial cultures. Our findings indicate that treatment with IL-35 modulates spinal microglia and alleviates neuropathic pain in male mice, suggesting IL-35 as a potential sex-specific targeted immunomodulatory treatment for neuropathic pain.

Recent advances in bacteria-based platforms for inflammatory bowel diseases treatment

Inflammatory bowel disease (IBD) is a recurring chronic inflammatory disease. Current treatment strategies are aimed at alleviating clinical symptoms and are associated with gastrointestinal or systemic adverse effects. New delivery strategies are needed for the treatment of IBD. Bacteria are promising biocarriers, which can produce drugs in situ and sense the gut in real time. Herein, we focus on recent studies of engineered bacteria used for IBD treatment and introduce the application of engineered bacteria in the diagnosis. On this basis, the current dilemmas and future developments of bacterial delivery systems are discussed.

Antioxidant and anti-inflammatory properties of water kefir microbiota and its bioactive metabolites for health promoting bio-functional products and applications

Inflammation and oxidative stress are implicated in several chronic disorders, while healthy foods and especially fermented beverages and those containing probiotics can provide anti-inflammatory and antioxidant protection against such manifestations and the associated disorders. Water kefir is such a beverage that is rich in both probiotic microbiota and anti-inflammatory bioactives, with an increasing demand as an alternative to a fermented product based on non-dairy matrix with potential health properties. Within this study, the health-promoting properties of the most representative species and strains of microorganisms present in water kefir grains, as well as the health benefits attributed to the bioactive metabolites produced by each individual strain in a series of their cultures, were thoroughly reviewed. Emphasis was given to the antioxidant, antithrombotic, and anti-inflammatory bio-functionalities of both the cultured microorganisms and the bioactive metabolites produced in each case. Moreover, an extensive presentation of the antioxidant and anti-inflammatory health benefits observed from the overall water kefir cultures and classic water kefir beverages obtained were also conducted. Finally, the use of water kefir for the production of several other bio-functional products, including fermented functional foods, supplements, nutraceuticals, nutricosmetics, cosmeceuticals, and cosmetic applications with anti-inflammatory and antioxidant health promoting potential was also thoroughly discussed. Limitations and future perspectives on the use of water kefir, its microorganisms, and their bioactive metabolites are also outlined.

Upregulation of TCPTP in Macrophages Is Involved in IL-35 Mediated Attenuation of Experimental Colitis

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease with complex etiology. Interleukin-35 (IL-35), as a cytokine with immunomodulatory function, has been shown to have therapeutic effects on UC, but its mechanism is not yet clear. Therefore, we constructed Pichia pastoris stably expressing IL-35 which enables the cytokines to reach the diseased mucosa, and explored whether upregulation of T-cell protein tyrosine phosphatase (TCPTP) in macrophages is involved in the mechanisms of IL-35-mediated attenuation of UC. After the successful construction of engineered bacteria expressing IL-35, a colitis model was successfully induced by giving BALB/c mice a solution containing 3% dextran sulfate sodium (DSS). Mice were treated with Pichia/IL-35, empty plasmid-transformed Pichia (Pichia/0), or PBS by gavage, respectively. The expression of TCPTP in macrophages (RAW264.7, BMDMs) and intestinal tissues after IL-35 treatment was detected. After administration of Pichia/IL-35, the mice showed significant improvement in weight loss, bloody stools, and shortened colon. Colon pathology also showed that the inflammatory condition of mice in the Pichia/IL-35 treatment group was alleviated. Notably, Pichia/IL-35 treatment not only increases local M2 macrophages but also decreases the expression of inflammatory cytokine IL-6 in the colon. With Pichia/IL-35 treatment, the proportion of M1 macrophages, Th17, and Th1 cells in mouse MLNs were markedly decreased, while Tregs were significantly increased. In vitro experiments, IL-35 significantly promoted the expression of TCPTP in macrophages stimulated with LPS. Similarly, the mice in the Pichia/IL-35 group also expressed more TCPTP than that of the untreated group and the Pichia/0 group.

Lactococcus lactis as an Interleukin Delivery System for Prophylaxis and Treatment of Inflammatory and Autoimmune Diseases

Target delivery of therapeutic agents with anti-inflammatory properties using probiotics as delivery and recombinant protein expression vehicles is a promising approach for the prevention and treatment of many diseases, such as cancer and intestinal immune disorders. Lactococcus lactis, a Lactic Acid Bacteria (LAB) widely used in the dairy industry, is one of the most important microorganisms with GRAS status for human consumption, for which biotechnological tools have already been developed to express and deliver recombinant biomolecules with anti-inflammatory properties. Cytokines, for  example, are immune system communication molecules present at virtually all levels of the immune response. They are essential in cellular and humoral processes, such as hampering inflammation or adjuvating in the adaptive immune response, making them good candidates for therapeutic approaches. This review discusses the advances in the development of new therapies and prophylactic approaches using LAB to deliver/express cytokines for the treatment of inflammatory and autoimmune diseases in the future.

Interleukin-35 and Interleukin-37 anti-inflammatory effect on inflammatory bowel disease: Application of non-coding RNAs in IBD therapy

Inflammatory bowel disease (IBD) is a widespread autoimmune disease that may even be life-threatening. IBD is divided into two major subtypes: ulcerative colitis and Crohn's disease. Interleukin (IL)-35 and IL-37 are anti-inflammatory cytokines that belong to IL-12 and IL-1 families, respectively. Their recruitment relieves inflammation in various autoimmune diseases, including psoriasis, multiple sclerosis, rheumatoid arthritis, and IBD. Regulatory T cells (Tregs) and regulatory B cells (Bregs) are the primary producers of IL-35/IL-37. IL-35 and IL-37 orchestrate the regulation of the immune system through two main strategies: Blocking nuclear transcription factor kappa-B (NF-kB) and mitogen-activated protein kinase (MAPK) signaling pathways or promoting the proliferation of Tregs and Bregs. Moreover, IL-35 and IL-37 can also inhibit inflammation by adjusting the T helper (Th)17/Treg ratio balance. Among the anti-inflammatory cytokines, IL-35 and IL-37 have significant potential to reduce intestinal inflammation. Therefore, administering IL-35/IL-37-based drugs or blocking their inhibitor microRNAs could be a promising approach to alleviate IBD symptoms. Overall, in this review article, we summarized the therapeutic application of IL-35 and IL-37 in both human and experimental models of IBD. Also, it is hoped that this practical information will reach beyond IBD therapy and shed some light on treating all intestinal inflammations.

The Role of Genetically Engineered Probiotics for Treatment of Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

Many preclinical studies have demonstrated the effectiveness of genetically modified probiotics (gm probiotics) in animal models of inflammatory bowel disease (IBD).

OBJECTIVE

This systematic review was performed to investigate the role of gm probiotics in treating IBD and to clarify the involved mechanisms.

METHODS

PubMed, Web of Science, Cochrane Library, and Medline were searched from their inception to 18 September 2022 to identify preclinical and clinical studies exploring the efficacy of gm probiotics in IBD animal models or IBD patients. Two independent researchers extracted data from the included studies, and the data were pooled by the type of study; that is, preclinical or clinical.

RESULTS

Forty-five preclinical studies were included. In these studies, sodium dextran sulfate and trinitrobenzene sulfonic acid were used to induce colitis. Eleven probiotic species have been genetically modified to produce therapeutic substances, including IL-10, antimicrobial peptides, antioxidant enzymes, and short-chain fatty acids, with potential therapeutic properties against colitis. The results showed generally positive effects of gm probiotics in reducing disease activity and ameliorating intestinal damage in IBD models; however, the efficacy of gm probiotics compared to that of wild-type probiotics in many studies was unclear. The main mechanisms identified include modulation of the diversity and composition of the gut microbiota, production of regulatory metabolites by beneficial bacteria, reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of oxidative stress activity in the colon, and improvement of intestinal barrier integrity. Moreover, only one clinical trial with 10 patients with Crohn's disease was included, which showed that L. lactis producing IL-10 was safe, and a decrease in disease activity was observed in these patients.

CONCLUSIONS

Gm probiotics have a certain efficacy in colitis models through several mechanisms. However, given the scarcity of clinical trials, it is important for researchers to pay more attention to gm probiotics that are more effective and safer than wild-type probiotics to facilitate further clinical translation.

Regulatory T-cell stability and functional plasticity in health and disease

FOXP3-expressing regulatory T cells (T_reg ) are indispensable for immune homeostasis and tolerance, and in addition tissue-resident T_reg have been found to perform noncanonical, tissue-specific functions. For optimal tolerogenic function during inflammatory disease, T_reg are equipped with mechanisms that assure lineage stability. T_reg lineage stability is closely linked to the installation and maintenance of a lineage-specific epigenetic landscape, specifically a T_reg -specific DNA demethylation pattern. At the same time, for local and directed immune regulation T_reg must possess a level of functional plasticity that requires them to partially acquire T helper cell (T_H ) transcriptional programs-then referred to as T_H -like T_reg . Unleashing T_H programs in T_reg , however, is not without risk and may threaten the epigenetic stability of T_reg with consequently pathogenic ex-T_reg contributing to (auto-) inflammatory conditions. Here, we review how the T_reg -stabilizing epigenetic landscape is installed and maintained, and further discuss the development, necessity and lineage instability risks of T_H 1-, T_H 2-, T_H 17-like T_reg and follicular T_reg .

Encouraging Tactics with Genetically Modified Probiotics to Improve Immunity for the Prevention of Immune-Related Diseases including Cardio-Metabolic Disorders

The PI3K/AKT/mTOR signaling pathway may play crucial roles in the pathogenesis of obesity and diabetes mellitus, as well as metabolic syndromes, which could also be risk factors for cardio-metabolic disorders. Consistently, it has been shown that beneficial effects may be convoyed by the modulation of the PI3K/AKT/mTOR pathway against the development of these diseases. Importantly, the PI3K/AKT/mTOR signaling pathway can be modulated by probiotics. Probiotics have a variety of beneficial properties, with the potential of treating specific diseases such as immune-related diseases, which are valuable to human health. In addition, an increasing body of work in the literature emphasized the contribution of genetically modified probiotics. There now seems to be a turning point in the research of probiotics. A better understanding of the interactions between microbiota, lifestyle, and host factors such as genetics and/or epigenetics might lead to a novel therapeutic approach with probiotics for these diseases. This study might provide a theoretical reference for the development of genetically modified probiotics in health products and/or in functional foods for the treatment of cardio-metabolic disorders.

Intestinal Engineered Probiotics as Living Therapeutics: Chassis Selection, Colonization Enhancement, Gene Circuit Design, and Biocontainment

Intestinal probiotics are often used for the in situ treatment of diseases, such as metabolic disorders, tumors, and chronic inflammatory infections. Recently, there has been an increased emphasis on intelligent, customized treatments with a focus on long-term efficacy; however, traditional probiotic therapy has not kept up with this trend. The use of synthetic biology to construct gut-engineered probiotics as live therapeutics is a promising avenue in the treatment of specific diseases, such as phenylketonuria and inflammatory bowel disease. These studies generally involve a series of fundamental design issues: choosing an engineered chassis, improving the colonization ability of engineered probiotics, designing functional gene circuits, and ensuring the safety of engineered probiotics. In this review, we summarize the relevant past research, the progress of current research, and discuss the key issues that restrict the widespread application of intestinal engineered probiotic living therapeutics.

Opportunities and challenges for synthetic biology in the therapy of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a complex, chronic intestinal inflammatory disorder that primarily includes Crohn’s disease (CD) and ulcerative colitis (UC). Although traditional antibiotics and immunosuppressants are known as the most effective and commonly used treatments, some limitations may be expected, such as limited efficacy in a small number of patients and gut flora disruption. A great many research studies have been done with respect to the etiology of IBD, while the composition of the gut microbiota is suggested as one of the most influential factors. Along with the development of synthetic biology and the continuing clarification of IBD etiology, broader prospects for novel approaches to IBD therapy could be obtained. This study presents an overview of the currently existing treatment options and possible therapeutic targets at the preclinical stage with respect to microbial synthesis technology in biological therapy. This study is highly correlated to the following topics: microbiota-derived metabolites, microRNAs, cell therapy, calreticulin, live biotherapeutic products (LBP), fecal microbiota transplantation (FMT), bacteriophages, engineered bacteria, and their functional secreted synthetic products for IBD medical implementation. Considering microorganisms as the main therapeutic component, as a result, the related clinical trial stability, effectiveness, and safety analysis may be the major challenges for upcoming research. This article strives to provide pharmaceutical researchers and developers with the most up-to-date information for adjuvant medicinal therapies based on synthetic biology.

Role of the microbiome in oral cancer occurrence, progression and therapy

The oral cavity, like other digestive or mucosal sites, contains a site-specific microbiome that plays a significant role in maintaining health and homeostasis. Strictly speaking, the gastrointestinal tract starts from the oral cavity, with special attention paid to the specific flora of the oral cavity. In healthy people, the microbiome of the oral microenvironment is governed by beneficial bacteria, that benefit the host by symbiosis. When a microecological imbalance occurs, changes in immune and metabolic signals affect the characteristics of cancer, as well as chronic inflammation, disruption of the epithelial barrier, changes in cell proliferation and cell apoptosis, genomic instability, angiogenesis, and epithelial barrier destruction and metabolic regulation. These pathophysiological changes could result in oral cancer. Rising evidence suggests that oral dysbacteriosis and particular microbes may play a positive role in the evolution, development, progression, and metastasis of oral cancer, for instance, oral squamous cell carcinoma (OSCC) through direct or indirect action.

Light-Sensitive Lactococcus lactis for Microbe-Gut-Brain Axis Regulating via Upconversion Optogenetic Micro-Nano System

The discovery of the gut-brain axis has proven that brain functions can be affected by the gut microbiota's metabolites, so there are significant opportunities to explore new tools to regulate gut microbiota and thus work on the brain functions. Meanwhile, engineered bacteria as oral live biotherapeutic agents to regulate the host's healthy homeostasis have attracted much attention in microbial therapy. However, whether this strategy is able to remotely regulate the host's brain function in vivo has not been investigated. Here, we engineered three blue-light-responsive probiotics as oral live biotherapeutic agents. They are spatiotemporally delivered and controlled by the upconversion optogenetic micro-nano system. This micro-nano system promotes the small intestine targeting and production of the exogenous L. lactis in the intestines, which realizes precise manipulation of brain functions including anxiety behavior, Parkinson's disease, and vagal afferent. The noninvasive and real-time probiotic intervention strategy makes the communiation from the gut to the host more controllable, which will enable the potential for engineered microbes accurately and effectively regulating a host's health.

Pentosan Polysulfate Sodium augments the therapeutic effect of 5-Aminosalicylic Acid in DSS colitis model; the role of IL-35 expression

Ulcerative colitis (UC) primarily affects the mucosa of the distal colon. Dysregulated immune response in genetically-prone persons is claimed to be responsible for chronic intestinal inflammation. This study aimed to explore the efficacy and the hematological effects of pentosan polysulfate sodium (PPS) in a dextran sulfate sodium (DSS)-induced colitis model. Forty C57BL/6 female mice were equally divided into five groups: control group, DSS-colitis group, DSS-colitis treated with 5-aminosalicylic acid, DSS-colitis treated with PPS, and DSS-colitis treated with both drugs. Disease activity index (DAI) and colon length were calculated. Colonic IL-6 and IL-35 levels were assayed by ELISA. IL-35 gene expression was evaluated by qRT-PCR. Colon tissue samples were examined by H&E stain and immunohistochemistry (IHC) of Ki67. The colitis group subjected to combined treatment showed the best outcome with significant improvement of DAI and increased colon length. Colonic IL-6 was significantly lower in both PPS- and combination-treated groups accompanied by a significantly higher IL-35 level and its EBI3 subunit mRNA expression. However, the PPS-treated colitis group showed higher gene expression of IL-35 EBI3 subunit by 1.5-fold compared with the combined group. The colon mucosa and crypts were significantly preserved in mice treated with both drugs with the best Ki67 positive cell density. PPS is a safe and promising drug in the treatment of UC as it exerted the best positive effect on the anti-inflammatory IL-35 level and gene expression. However, superior improvement of DAI was seen when PPS was added to ASA with a greater mucosal proliferation and repair.

Interleukin-35: Structure, Function and Its Impact on Immune-Related Diseases

The balance between inflammatory and anti-inflammatory immune responses is maintained through immunoregulatory cell populations and immunosuppressive cytokines. Interleukin-35 (IL-35), an inhibitory cytokine that belongs to the IL-12 family, is capable of potently suppressing T cell proliferation and inducing IL-35-producing induced regulatory T cells (iTr35) to limit inflammatory responses. Over the past decade, a growing number of studies have indicated that IL-35 plays an important role in controlling immune-related disorders, including autoimmune diseases, infectious diseases, and cancer. In this review, we summarize the current knowledge about the biology of IL-35 and its contribution in different diseases, and we discuss the potential of and barriers to harnessing IL-35 as a clinical biomarker or immunotherapy.

Bacteria-Based Microdevices for the Oral Delivery of Macromolecules

The oral delivery of macromolecules is quite challenging due to environmental insults and biological barriers encountered along the gastrointestinal (GI) tract. Benefiting from their living characteristics, diverse bacterial species have been engineered as intelligent platforms to deliver various therapeutics. To tackle difficulties in oral delivery, innovative bacteria-based microdevices have been developed by virtue of advancements in synthetic biology and nanotechnology, with aims to overcome the instability and short half-life of macromolecules in the GI tract. In this review, we summarize the main classes of macromolecules that are produced and delivered through the oral ingestion of bacteria and bacterial derivatives. Furtherly, we discuss the engineering strategies and biomedical applications of these living microdevices in disease diagnosis, bioimaging, and treatment. Finally, we highlight the advantages as well as the limitations of these engineered bacteria used as platforms for the oral delivery of macromolecules and also propose their potential for clinical translation. The results summarized in this review article would contribute to the invention of next-generation bacteria-based systems for the oral delivery of macromolecules.

Lactococcus lactis Expressing Type I Interferon From Atlantic Salmon Enhances the Innate Antiviral Immune Response In Vivo and In Vitro

In salmon farming, viruses are responsible for outbreaks that produce significant economic losses for which there is a lack of control tools other than vaccines. Type I interferon has been successfully used for treating some chronic viral infections in humans. However, its application in salmonids depends on the proper design of a vehicle that allows its massive administration, ideally orally. In mammals, administration of recombinant probiotics capable of expressing cytokines has shown local and systemic therapeutic effects. In this work, we evaluate the use of Lactococcus lactis as a type I Interferon expression system in Atlantic salmon, and we analyze its ability to stimulate the antiviral immune response against IPNV, in vivo and in vitro. The interferon expressed in L. lactis, even though it was located mainly in the bacterial cytoplasm, was functional, stimulating Mx and PKR expression in CHSE-214 cells, and reducing the IPNV viral load in SHK-1 cells. In vivo, the oral administration of this L. lactis producer of Interferon I increases Mx and PKR expression, mainly in the spleen, and to a lesser extent, in the head kidney. The oral administration of this strain also reduces the IPNV viral load in Atlantic salmon specimens challenged with this pathogen. Our results show that oral administration of L. lactis producing Interferon I induces systemic effects in Atlantic salmon, allowing to stimulate the antiviral immune response. This probiotic could have effects against a wide variety of viruses that infect Atlantic salmon and also be effective in other salmonids due to the high identity among their type I interferons.

Efficient Stool Collection Methods for Evaluating the Diarrhea Score in Mouse Diarrhea Models

BACKGROUND/AIM

The mouse diarrhea score is usually determined by evaluating stool consistency and shape. Thus, defecated stools should be collected without damage or contamination. The study aimed to develop improved mouse stool collection methods and diarrhea-scoring criteria.

MATERIALS AND METHODS

We developed improved stool collection methods (paper towel methods) and compared them with previously used ones (stool collection using regular cages containing bedding chips or filter paper and metabolic cages).

RESULTS

Compared to previously used methods, paper towel methods collected stools without bedding chips-induced contamination, mouse body/foot-induced damage, or sampling errors. When using paper towel methods, wet stools create water marks (diarrhea marks) on paper towels with strong water absorption capacity, by which diarrheal severity can be analyzed semi-quantitatively. To improve the objectivity in determining diarrhea scores, practical diarrhea-scoring criteria were also proposed.

CONCLUSION

These results would be helpful to researchers facing difficulties in evaluating the mouse diarrhea score.

The Anti-Tumor Effect of Lactococcus lactis Bacteria-Secreting Human Soluble TRAIL Can Be Enhanced by Metformin Both In Vitro and In Vivo in a Mouse Model of Human Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is a major cause of morbidity and mortality in Europe, and accounts for over 10% of all cancer-related deaths worldwide. These indicate an urgent need for novel therapeutic options in CRC. Here, we analysed if genetically modified non-pathogenic Lactococcus lactis bacteria can be used for local delivery of human recombinant Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) and induction of tumor cells death in vitro and in vivo in CRC mouse model. We showed that modified L. lactis bacteria were able to secrete biologically active human soluble TRAIL (L. lactis(hsTRAIL+)), which selectively eliminated human CRC cells in vitro, and was further strengthened by metformin (MetF). Our results from in vitro studies were confirmed in vivo using subcutaneous NOD-SCID mouse model of human CRC. The data showed a significant reduction of the tumor growth by intratumor injection of L. lactis(hsTRAIL+) bacteria producing hsTRAIL. This effect could be further enhanced by oral administration of MetF.

Abstract

Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) induces apoptosis of many cancer cells, including CRC cells, being non-harmful for normal ones. However, recombinant form of human TRAIL failed in clinical trial when administered intravenously. To assess the importance of TRAIL in CRC patients, new form of TRAIL delivery would be required. Here we used genetically modified, non-pathogenic Lactococcus lactis bacteria as a vehicle for local delivery of human soluble TRAIL (hsTRAIL) in CRC. Operating under the Nisin Controlled Gene Expression System (NICE), the modified bacteria (L. lactis(hsTRAIL+)) were able to induce cell death of HCT116 and SW480 human cancer cells and reduce the growth of HCT116-tumor spheres in vitro. This effect was cancer cell specific as the cells of normal colon epithelium (FHC cells) were not affected by hsTRAIL-producing bacteria. Metformin (MetF), 5-fluorouracil (5-FU) and irinotecan (CPT-11) enhanced the anti-tumor actions of hsTRAIL in vitro. In the NOD-SCID mouse model, treatment of subcutaneous HCT116-tumors with L. lactis(hsTRAIL+) bacteria given intratumorally, significantly reduced the tumor growth. This anti-tumor activity of hsTRAIL in vivo was further enhanced by oral administration of MetF. These findings indicate that L. lactis bacteria could be suitable for local delivery of biologically active human proteins. At the same time, we documented that anti-tumor activity of hsTRAIL in experimental therapy of CRC can be further enhanced by MetF given orally, opening a venue for alternative CRC-treatment strategies.

Plasmid Replicons for the Production of Pharmaceutical-Grade pDNA, Proteins and Antigens by Lactococcus lactis Cell Factories

The Lactococcus lactis bacterium found in different natural environments is traditionally associated with the fermented food industry. But recently, its applications have been spreading to the pharmaceutical industry, which has exploited its probiotic characteristics and is moving towards its use as cell factories for the production of added-value recombinant proteins and plasmid DNA (pDNA) for DNA vaccination, as a safer and industrially profitable alternative to the traditional Escherichia coli host. Additionally, due to its food-grade and generally recognized safe status, there have been an increasing number of studies about its use in live mucosal vaccination. In this review, we critically systematize the plasmid replicons available for the production of pharmaceutical-grade pDNA and recombinant proteins by L. lactis. A plasmid vector is an easily customized component when the goal is to engineer bacteria in order to produce a heterologous compound in industrially significant amounts, as an alternative to genomic DNA modifications. The additional burden to the cell depends on plasmid copy number and on the expression level, targeting location and type of protein expressed. For live mucosal vaccination applications, besides the presence of the necessary regulatory sequences, it is imperative that cells produce the antigen of interest in sufficient yields. The cell wall anchored antigens had shown more promising results in live mucosal vaccination studies, when compared with intracellular or secreted antigens. On the other side, engineering L. lactis to express membrane proteins, especially if they have a eukaryotic background, increases the overall cellular burden. The different alternative replicons for live mucosal vaccination, using L. lactis as the DNA vaccine carrier or the antigen producer, are critically reviewed, as a starting platform to choose or engineer the best vector for each application.

GutBalance: a server for the human gut microbiome-based disease prediction and biomarker discovery with compositionality addressed

The compositionality of the microbiome data is well-known but often neglected. The compositional transformation pertains to the supervised learning of microbiome data and is a critical step that decides the performance and reliability of the disease classifiers. We value the excellent performance of the distal discriminative balance analysis (DBA) method, which selects distal balances of pairs and trios of bacteria, in addressing the classification of high-dimensional microbiome data. By applying this method to the species-level abundances of all the disease phenotypes in the GMrepo database, we build a balance-based model repository for the classification of human gut microbiome-related diseases. The model repository supports the prediction of disease risks for new sample(s). More importantly, we highlight the concept of balance-disease associations rather than the conventional microbe-disease associations and develop the human Gut Balance-Disease Association Database (GBDAD). Each predictable balance for each disease model indicates a potential biomarker-disease relationship and can be interpreted as a bacteria ratio positively or negatively correlated with the disease. Furthermore, by linking the balance-disease associations to the evidenced microbe-disease associations in MicroPhenoDB, we surprisingly found that most species-disease associations inferred from the shotgun metagenomic datasets can be validated by external evidence beyond MicroPhenoDB. The balance-based species-disease association inference will accelerate the generation of new microbe-disease association hypotheses in gastrointestinal microecology research and clinical trials. The model repository and the GBDAD database are deployed on the GutBalance server, which supports interactive visualization and systematic interrogation of the disease models, disease-related balances and disease-related species of interest.

Microbial therapeutics for acute colitis based on genetically modified Lactococcus lactis hypersecreting IL-1Ra in mice

The increased incidence of inflammatory bowel disease (IBD) in Western and rapidly Westernizing developing countries poses a global pandemic threat. The development of affordable drugs for treating IBD worldwide is thus a priority. Genetically modified lactic acid bacteria (gmLAB) as microbial therapeutics are inexpensive protein producers suitable for use as carriers of protein to the intestinal mucosa. Here, we successfully constructed gmLAB hypersecreting interleukin 1 receptor antagonist (IL-1Ra). Oral administration of these gmLAB suppressed body weight reduction and exacerbation of the disease activity index score in mice with acute colitis and decreased the number of CD4⁺ IL-17A⁺ cells in the mesenteric lymph nodes. These data suggest that the gmLAB deliver IL-1Ra to the colon, where it inhibits IL-1 signaling. We thus developed a novel IBD therapeutic that blocks IL-1 signaling using a gmLAB protein delivery system. This system could be an inexpensive oral microbial therapeutic.

Genetically reprogrammed bacteria can facilitate the efficient delivery of a therapeutic protein for treating inflammatory bowel disease (IBD). Interleukin 1 receptor antagonist (IL-1Ra) inhibits the immune cells that attack the intestinal lining in IBD patients, but current administration strategies are associated with serious side effects. Takeshi Shimosato and colleagues at Shinshu University in Nagano, Japan, have engineered the microbe Lactococcus lactis to secrete high levels of IL-1Ra. The researchers dosed mice orally with these bacteria, which released IL-1Ra into the intestinal tissue. This treatment proved safe and effectively reduced inflammation and associated symptoms in a mouse model of ulcerative colitis. L. lactis has previously been tested as a probiotic in clinical trials, and may therefore offer an appealing alternative to subcutaneous administration of IBD drugs in human patients.

Interplay between Cytokine Circuitry and Transcriptional Regulation Shaping Helper T Cell Pathogenicity and Plasticity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disorder manifested as Crohn’s disease (CD) and ulcerative colitis (UC) characterized by intestinal inflammation and involves a dysregulated immune response against commensal microbiota through the activation of CD4 T helper cells. T helper cell differentiation to effector or regulatory phenotypes is controlled by cytokine networks and transcriptional regulators. Distinct polarized T helper cells are able to alter their phenotypes to adapt to diverse and fluctuating physiological environments. T helper cells exhibit intrinsic instability and flexibility to express cytokines of other lineages or transdifferentiate from one T helper cell type to another in response to various perturbations from physiological cytokine milieu as a means of promoting local immunity in response to injury or ensure tissue homeostasis. Furthermore, functional plasticity and diversity of T helper cells are associated with pathogenicity and are critical for immune homeostasis and prevention of autoimmunity. In this review, we provide deeper insights into the combinatorial extrinsic and intrinsic signals that control plasticity and transdifferentiation of T helper cells and also highlight the potential of exploiting the genetic reprogramming plasticity of T helper cells in the treatment of IBD.

Protective effects of panax notoginseng saponin on dextran sulfate sodium-induced colitis in rats through phosphoinositide-3-kinase protein kinase B signaling pathway inhibition

BACKGROUND

Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.

AIM

To explore the protective effects of panax notoginseng saponin (PNS) against dextran sulfate sodium (DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B (PI3K/AKT) signaling pathway inhibition in rats.

METHODS

Colitis rat models were generated via DSS induction, and rats were divided into control (no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.

RESULTS

Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers, and showed significantly increased M1 macrophages in spleen and colon tissues. They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway (all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency (all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group (P < 0.05).

CONCLUSION

PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.