Mucosal immunity-mediated modulation of the gut microbiome by oral delivery of probiotics into Peyer's patches

Metal ion coordinated tea polyphenol nanocoating for enhanced probiotic therapy in inflammatory bowel disease

Probiotics encapsulated with metal-phenolic networks (MPNs) present a promising approach for treating inflammatory bowel diseases (IBD). However, current MPN systems predominantly use tannic acid (TA) as the phenolic source, with limited exploration of other polyphenols, and face challenges in long-term stability and biocompatibility. Herein, three alternative tea polyphenols, gallic acid (GA), epigallocatechin (EGC) and epigallocatechin gallate (EGCG), were coordinated with ferric ions, to fabricate MPN-coated Lactobacillus rhamnosus LGG (MPN@L). These were compared with TA-based MPN@L to evaluate their effectiveness in alleviating IBD. All MPN@L complexes demonstrated superior adhesion and retention compared to uncoated probiotics in both ex vivo and in vivo models. Specifically, EGC@L exhibited the highest survival rate throughout gastrointestinal digestion, with a 2.7 log CFU/mL improvement over uncoated probiotics, and showed optimal retention in murine intestine with a fluorescence intensity of 24.3 × 106 p/s/cm2/sr by day four. All MPN@L formation effectively alleviated ulcerative colitis by reducing myeloperoxidase levels, modulating cytokines profiles, and enhancing gut microbiota. EGC@L particularly increased beneficial bacterial genera, including Lactobacillus, Adlercreutzia, and Oscillospira, while decreasing the pro-inflammatory genera. This study highlights the potential of MPN-based probiotic microencapsulation to enhanced treatment for gastrointestinal disorders, expending the application of probiotic microencapsulation in IBD therapy.

Surface-functionalized bacteria: Frontier explorations in next-generation live biotherapeutics

Screening robust living bacteria to produce living biotherapeutic products (LBPs) represents a burgeoning research field in biomedical applications. Despite their natural abilities to colonize bio-interfaces and proliferate, harnessing bacteria for such applications is hindered by considerable challenges in unsatisfied functionalities and safety concerns. Leveraging the high degree of customization and adaptability on the surface of bacteria demonstrates significant potential to improve therapeutic outcomes and achieve tailored functionalities of LBPs. This review focuses on the recent laboratory strategies of bacterial surface functionalization, which aims to address these challenges and potentiate the therapeutic effects in biomedicine. Firstly, we introduce various functional materials that are used for bacterial surface functionalization involving organic, inorganic, and biological materials. Secondly, the methodologies for achieving bacterial surface functionalization are categorized into three primary approaches including covalent bonding, non-covalent interactions, and hybrid techniques, while various advantages and limitations of different modification strategies are compared from multiple perspectives. Subsequently, the current status of the applications of surface-functionalized bacteria in bioimaging and disease treatments, especially in the treatment of inflammatory bowel disease (IBD) and cancer is summarized. Finally, challenges and pressing issues in the development of surface-functionalized bacteria as LBPs are presented.

Layer-by-Layer Deposition of Antigen Peptides on Bifidobacterium for Subintestinal Lymphatic System-Guided Personalized Tumor Immunotherapy

Gut-associated lymphoid tissue (GALT) possesses a highly specialized immune system and is rational as a foothold for oral tumor vaccines. Here, a noninvasive oral vaccine (Bif-OVA-Ocur) is designed to engage GALT, inducing both intestinal mucosal and systemic immunity for tumor therapeutics. The vaccine uses Bifidobacterium (Bif) as a delivery vehicle for tumor antigen peptides, which are coated with antigen peptides (OVA) and oxidized curdlan (Ocur) in a layer-by-layer (LBL) manner. Upon oral administration, Bif-OVA-Ocur is efficiently directed to Peyer's patches (PPs) in the intestines and further presented to antigen-presenting cells (APCs), which then migrate to the mesenteric lymph nodes (MLNs) to evoke specific T cell responses. In mouse models, Bif-OVA-Ocur effectively boosts the production of secretory immunoglobin A (SIgA) and promotes a strong mucosal and systemic immune response, leading to significant tumor suppression and resistance to tumor challenges. Importantly, the vaccine shows no systemic toxicity. This approach to harnessing the intestinal mucosal immune system offers valuable insights for the development of other non-invasive oral vaccines and therapeutic agents.

The Encapsulation Strategies for Targeted Delivery of Probiotics in Preventing and Treating Colorectal Cancer: A Review

Colorectal cancer (CRC) ranks as the third most prevalent cancer worldwide. It is associated with imbalanced gut microbiota. Probiotics can help restore this balance, potentially reducing the risk of CRC. However, the hostile environment and constant changes in the gastrointestinal tract pose significant challenges to the efficient delivery of probiotics to the colon. Traditional delivery methods are often insufficient due to their low viability and lack of targeting. To address these challenges, researchers are increasingly focusing on innovative encapsulation technologies. One such approach is single-cell encapsulation, which involves applying nanocoatings to individual probiotic cells. This technique can improve their resistance to the harsh gastrointestinal environment, enhance mucosal adhesion, and facilitate targeted release, thereby increasing the effectiveness of probiotic delivery. This article reviews the latest developments in probiotic encapsulation methods for targeted CRC treatment, emphasizing the potential benefits of emerging single-cell encapsulation techniques. It also analyzes and compares the advantages and disadvantages of current encapsulation technologies. Furthermore, it elucidates the underlying mechanisms through which probiotics can prevent and treat CRC, evaluates the efficacy and safety of probiotics in CRC treatment and adjuvant therapy, and discusses future directions and potential challenges in the targeted delivery of probiotics for CRC treatment and prevention.

Evaluating the efficacy and safety of emodin, luteolin, and paeonol combination from Dahuang Mudan decoction in ameliorating ulcerative colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Dahuang Mudan Decoction is a classic Chinese medicine prescription for treating ulcerative colitis (UC). Previous studies have shown that Dahuang Mudan Decoction has preventive and therapeutic effects on mice with dextran sulfate sodium (DSS) induced colitis.

AIM OF THE STUDY

The objective of this research endeavor was to ascertain the most efficacious synergistic blend of Emodin, Luteolin, and Paeonol, the main active ingredients in Dahuang Mudan Decoction, in alleviating UC. Additionally, it sought to elucidate the underlying therapeutic mechanisms and evaluate the safety of the combined components.

MATERIALS AND METHODS

Employing Emodin, Luteolin, and Paeonol as starting materials, the optimal combination was selected by orthogonal design. Basic pharmacodynamics was observed in mouse model of UC induced by DSS. The pathological changes of the colon were observed using hematoxylin and eosin (H&E) staining. The changes of cytokines and proteins related to inflammation and intestinal barrier function were detected by WB, Alcian blue staining, immunofluorescence, immunohistochemistry and related kits. Subsequently, 16S rRNA sequencing was used to observe changes in the intestinal flora. To evaluate the therapeutic effect and potential mechanism of the optimal monomer composition on UC mouse model. Finally, we performed toxicity tests as part of the safety assessment of the combination of the three monomers.

RESULTS

The different combinations of Emodin, Luteolin, and Paeonol alleviated DSS-induced colitis to varying degrees. The ELP5 group (Emodin 5 mg/kg + Luteolin 5 mg/kg + Paeonol 15 mg/kg) and ELP9 group (Emodin 15 mg/kg + Luteolin 15 mg/kg + Paeonol 75 mg/kg) had the most significant mitigation effect on UC mice. Mechanistically, the monomeric composition provides a comprehensive treatment for UC by addressing multiple aspects, including anti-inflammatory and antioxidant effects, repairing the damaged intestinal barrier, restoring the intestinal flora structure, and regulating short-chain fatty acid levels. In addition, the combination of Emodin, Luteolin and Paeonol exhibited a more significant effect on DSS-induced colitis compared to the individual components, indicating a synergistic effect among them. In the single-dose toxicity test, no obvious abnormalities were found in the general state or major organs of the mice. In repeated toxicity tests, it was found that the combined use of three monomers had less effect on organ index, hematology and serum biochemical indexes than that of a single compound. Pathological examination showed that the three monomers had certain toxicity to mouse liver, kidney and lung when used alone and in large doses for a long time, and the toxicity was significantly reduced after combined use.

CONCLUSIONS

We have determined the optimal combination of three active ingredients in Dahuang Mudan Decoction to alleviate DSS induced colitis in mice by inhibiting intestinal inflammation and oxidative stress, repairing impaired intestinal barrier function, and regulating intestinal flora disturbance. The results of single administration toxicity test proved the safety of the three monomers combined, and repeated administration toxicity test clarified the safe dose range of the combined administration, and also revealed that the combined therapy exhibited superior safety compared to monotherapy.

Triple-Functional Probiotics with Intracellularly Synthesized Selenium Nanoparticles for Colitis Therapy by Regulating the Macrophage Phenotype and Modulating Gut Microbiota

The dysregulated macrophage phenotype, as the main cause of colitis, not only enhanced oxidative stress to exacerbate inflammatory responses but was closely related with gut microbial dysbiosis. It was needed to simultaneously address the three issues for the effective treatment of colitis, but it was not satisfied. Here, we developed "three-birds-one-stone" probiotics, named Se@EcN-C2/A2, for colitis treatment. Escherichia coli Nissle 1917 (EcN), a clinically approved probiotic, was used to intracellularly synthesize selenium (Se) nanoparticles by biomineralization, giving Se@EcN. Coating glycol chitosan and sodium alginate on the surface of Se@EcN (Se@EcN-C2/A2) endowed probiotics with high resistance to the harsh gastrointestinal tract environment and strong adhesion and targeting ability to the inflamed site of the colon to facilitate the uptake by M1 macrophages. Se@EcN-C2/A2 was metabolized to SeCys2 and MetSeCys to be involved in the synthesis of GPX2 and TXNRD1, which led to reaction oxygen species clearance to inhibit Toll-like receptor and nuclear factor κB signaling pathways to suppress inflammatory response and polarize M1 macrophages to M2 phenotypes by activating PI3K/AKT signaling pathways. In DSS-induced colitis mice, Se@EcN-C2/A2 exerted satisfactory therapeutic and prophylactic effects, including scavenging oxidative stress and regulating macrophage phenotypes to suppress inflammatory response and restore gut barrier functions. Moreover, the living probiotic EcN in the colon effectively regulated microbial dysbiosis by decreasing the abundance of Escherichia-Shigella and increasing the abundance of Lactobacillus and Bifidobacterium.

Magnetically targeted delivery of probiotics for controlled residence and accumulation in the intestine

The effectiveness of orally delivered probiotics in treating gastrointestinal diseases is restricted by inadequate gut retention. In this study, we present a magnetically controlled strategy for probiotic delivery, which enables controlled accumulation and residence of probiotics in the intestine. The magnetically controlled probiotic is established by attaching amino-modified iron oxide (Fe3O4-NH3+ NPs) to polydopamine-coated Lacticaseibacillus rhamnosus GG (LGG@P) through electrostatic self-assembly and named as LGG@P@Fe3O4. In a simulated gastrointestinal environment, LGG@P@Fe3O4 maintains both structural stability and probiotic viability. Furthermore, the LGG@P@Fe3O4 clusters can be easily manipulated by an external magnetic field, inducing directional movement and aggregation. In vitro simulations demonstrated significant accumulation and retention of LGG@P@Fe3O4 under a magnetic field, with the optical density (OD) value of the suspension decreasing from ∼1.17 to ∼0.29. In contrast, the OD value of the suspension without a magnetic field remained at its original level (∼1.15). In a mouse model with intragastrically administered LGG@P@Fe3O4, the group exposed to a magnet exhibited stronger gut fluorescence after 24 h. The magnetically controlled probiotic delivery strategy offers an easy manufacturing and feasible method to enhance the effectiveness of probiotics in treating gastrointestinal diseases.

CaGA nanozymes inhibit oxidative stress and protect mitochondrial function in ulcerative colitis therapy

Ulcerative colitis (UC) is a long-term inflammatory bowel disease characterized by intense inflammation of the colorectal mucosa. Overproduction of reactive oxygen species exacerbates the progression of UC, which is linked to mitochondrial impairment and dysbiosis of the intestinal microbiota. CaGA nanozymes have demonstrated efficacy in the treatment of UC. The modulation of M1 and M2 polarization of macrophages by CaGA nanozymes has been demonstrated to be useful in reducing inflammation. Furthermore, CaGA nanozymes regulate the M1 and M2 polarization of macrophages, efficiently decreasing inflammation. The oral delivery of CaGA nanozymes resulted in their enrichment in inflamed areas of the colon and effectively reduced colonic damage in mice with DSS-induced colitis by improving the repair of the intestinal barrier. An investigation of 16S rDNA sequencing revealed that CaGA nanozymes regulate populations of both pathogenic and helpful bacteria and impact the progression of ulcerative colitis by influencing the tricarboxylic acid (TCA) cycle. Thus, CaGA nanozymes may be employed in the management of ulcerative colitis to control the intestinal milieu and improve the preservation of the intestinal barrier by decreasing the invasion of inflammatory cells and restoring mitochondrial activity. STATEMENT OF SIGNIFICANCE: CaGA nanozymes exhibit multifunctional enzymatic activity, effectively eliminating cellular RONS with robust antioxidant capacity. CaGA nanoenzymes promote macrophage M1 to M2 polarization and produce anti-inflammatory effects. CaGA nanozymes increase cell viability by restoring impaired mitochondrial function, reducing reactive oxygen species (ROS) production, and restoring the ability of mitochondria to produce ATP. CaGA nanozymes modulate intestinal flora diversity and composition, potentially influencing inflammatory pathways via aromatic compound metabolism. They participate in cellular energy and biosynthesis, regulating ulcerative colitis (UC)-related intestinal function through the tricarboxylic acid (TCA) and urea cycles. Calcium ions bind to GA nanomedicine and small particles are readily absorbed by inflammatory cells, preventing diarrhea from being rapidly excreted.

Microfluidic-derived montmorillonite composite microparticles for oral codelivery of probiotic biofilm and postbiotics

Oral delivery of probiotics has shown promising effects in modulating the gut microbiota and treating ulcerative colitis (UC). However, the therapeutic efficacy is restricted by gastrointestinal assaults, poor mucosal adhesion, and single therapeutic modality. Here, we developed acid-resistant, gut-environment-responsive composite microparticles based on microfluidic electrospray for the oral codelivery of probiotic [Lactobacillus acidophilus (LA)] biofilm and postbiotics (indole-3-propionic acid). Montmorillonite was selected for supporting biofilm formation due to its cation-exchange capability and clearly defined biosafety. The montmorillonite-LA biofilm was effectively protected by the microparticles and markedly improved the intestinal retention. Upon oral administration, the composite microparticles notably alleviated colitis in mice, including reducing the inflammatory response, improving intestinal barrier function, and modulating the gut microbiota. Consequently, the composite microparticles show high potential for enhancing probiotic delivery efficacy and present a promising strategy for UC treatment.

Harnessing the power of breast milk: how Lactiplantibacillus plantarum FN029 from rural western China mitigates severe atopic dermatitis in mice through retinol metabolism activation

Tongwei and Wuxi represent a rural county in western China and an industrialized city in the east, respectively. The study compared breast milk and the corresponding infant gut microbiota from 35 healthy mothers in Tongwei and 28 in Wuxi, uncovering significant differences in microbial alpha and beta diversity. A unique strain, Lactiplantibacillus plantarum FN029, characteristically transmitted from breast milk to the infant gut in Tongwei, was identified. Oral administration of FN029 to weaned BALB/c mice significantly alleviated atopic dermatitis severity caused by calcipotriol and ovalbumin. This reduction was paralleled by a decrease in mast cells and eosinophils in ear tissue and reduced levels of IL-4, IL-12, IL-33, IFN-γ, the IL-4/IFN-γ ratio, and IgE in plasma, along with an upsurge in regulatory T cells in the spleen. RNA sequencing revealed that FN029 activated the retinol metabolism pathway and the Wnt signaling pathway, enhancing immature dendritic cells and regulatory T cells. Metabolomics analysis indicated an increase in retinyl beta-glucuronide, a biomarker of vitamin A reserves. The mRNA expression of retinol-metabolizing enzymes was inversely related to the IL-4/IFN-γ ratio. FN029 also altered ileum microbiota without a direct link to atopic dermatitis improvement. In conclusion, L. plantarum FN029, a probiotic from Tongwei breast milk, fostered T regulatory cell conversion and immune balance by activating the retinol pathway, thereby improving severe atopic dermatitis in mice.

Oral DNA Vaccine Utilizing the Yeast Cell Wall for Dectin-1 Receptor-Mediated Enhancement of Mucosal Immunity

Mucosal vaccines can generate localized mucosal immunity, effectively preventing initial pathogen infection and providing more effective protection. Oral vaccines are an attractive option for inducing mucosal immunity. The yeast cell wall, primarily composed of natural β-1,3-d glucan, can be recognized by the apical membrane receptor, dectin-1, which has a high expression on macrophages and intestinal M cells. In this study, by using vortexing methods to break yeast cell walls into nanometer-sized fragments, which retain the negatively charged β-glucan components on their surface and employing electrostatic adsorption/coextrusion techniques, these fragments were attached onto the surface of PS-DNA NPs, as verified by a scanning electron microscope (SEM), a transmission electron microscope (TEM), and dynamic light scattering (DLS) data. YCW-coated NPs (YNPs) showed greater drug stability compared to NPs in a simulated gastrointestinal environment. In vitro cell evaluation further demonstrated that YNPs were rapidly and efficiently taken up by antigen-presenting cells via receptor dectin-1-mediated endocytosis. In vivo experiments revealed that the oral vaccine elicited high levels of RBD-specific antibodies and triggered extensive cellular immunity in the intestinal mucosa. This study provides new insights into mucosal vaccine research.

Living Bacteria: A New Vehicle for Vaccine Delivery in Cancer Immunotherapy

Cancer vaccines, aimed at evolving the human immune system to eliminate tumor cells, have long been explored as a method of cancer treatment with significant clinical potential. Traditional delivery systems face significant challenges in directly targeting tumor cells and delivering adequate amounts of antigen due to the hostile tumor microenvironment. Emerging evidence suggests that certain bacteria naturally home in on tumors and modulate antitumor immunity, making bacterial vectors a promising vehicle for precision cancer vaccines. Live bacterial vehicles offer several advantages, including tumor colonization, precise drug delivery, and immune stimulation, making them a compelling option for cancer immunotherapy. In this review, we explore the mechanisms of action behind living bacteria-based vaccines, recent progress in popular bacterial chassis, and strategies for specific payload delivery and biocontainment to ensure safety. These approaches will lay the foundation for developing an affordable, widely applicable cancer vaccine delivery system. This review also discusses the challenges and future opportunities in harnessing bacterial-based vaccines for enhanced therapeutic outcomes in cancer treatment.

Yeast-Inspired Orally-Administered Nanocomposite Scavenges Oxidative Stress and Restores Gut Immune Homeostasis for Inflammatory Bowel Disease Treatment

Excessive oxidative stress, dysregulated immune homeostasis, and disruption of the intestinal epithelial barrier are crucial features of inflammatory bowel disease (IBD). Traditional treatments focusing solely on inflammation resolution remain unsatisfactory. Herein, a yeast-inspired orally administered nanocomposite was developed. First, the MD@MPDA core was fabricated by integrating manganese dioxide (MnO2) nanozymes onto diallyl trisulfide (H2S prodrug)-loaded mesoporous polydopamine nanoparticles (MPDA). Then, yeast cell wall (YCW) was chosen to encapsulate MD@MPDA, namely, YMD@MPDA. The β-glucan embedded in the YCW shell not only protected the nanocomposite from the harsh gastrointestinal environment but also allowed the targeting enrichment in the inflamed colon. Furthermore, M1 macrophages triggered the intracellular GSH-responsive H2S release in the pathological microenvironment. MD@MPDA effectively alleviated inflammatory responses by MnO2-mediated ROS-scavenging and H2S-participated immunomodulation. The synergistic action contributed to macrophage mitochondrial function restoration and M2 polarization by suppressing NOX4 signaling and p38 MAPK pro-inflammatory signaling. In the mice model of dextran sulfate sodium (DSS)-induced IBD, the multipronged manner of scavenging oxidative stress, remodeling innate and adaptive immune homeostasis, and reshaping gut microbiota caused by YMD@MPDA effectively ameliorated inflammation and restored intestinal barrier functions. Overall, the YMD@MPDA nanocomposite provides a promising codelivery strategy of antioxidative nanozymes and gas prodrugs for the comprehensive management of IBD.

Genetically Engineered Bacteria as a Promising Therapeutic Strategy Against Cancer: A Comprehensive Review

As a significant cause of global mortality, the cancer has also economic impacts. In the era of cancer therapy, mitigating side effects and costs and overcoming drug resistance is crucial. Microbial species can grow inside the tumor microenvironment and inhibit cancer growth through direct killing of tumor cells and immunoregulatory effects. Although microbiota or their products have demonstrated anticancer effects, the possibility of acting as pathogens and exerting side effects in certain individuals is a risk. Hence, several genetically modified/engineered bacteria (GEB) have been developed to this aim with ability of diagnosing and selective targeting and destruction of cancers. Additionally, GEB are expected to be considerably more efficient, safer, more permeable, less costly, and less invasive theranostic approaches compared to wild types. Potential GEB strains such as Escherichia coli (Nissle 1917, and MG1655), Salmonella typhimurium YB1 SL7207 (aroA gene deletion), VNP20009 (∆msbB/∆purI) and ΔppGpp (PTet and PBAD), and Listeria monocytogenes Lmat-LLO have been developed to combat cancer cells. When used in tandem with conventional treatments, GEB substantially improve the efficacy of anticancer therapy outcomes. In addition, public acceptance, optimal timing (s), duration (s), dose (s), and strains identification, interactions with other strains and the host cells, efficacy, safety and quality, and potential risks and ethical dilemmas include major challenges.

Adhesive polyelectrolyte coating through UV-triggered polymerization on PLGA particles for enhanced drug delivery to inflammatory intestinal mucosa

Administering medication precisely to the inflamed intestinal sites to treat ulcerative colitis (UC), with minimized side effects, is of urgent need. In UC, the inflammation damaged mucosa contains a large number of amino groups which are positively charged, providing new opportunities for drug delivery system design. Here, we report an oral drug delivery system utilizing the tacrolimus-loaded poly (lactic-co-glycolic acid) (TAC/PLGA) particles with an adhesion coating by in situ UV-triggered polymerization of polyacrylic acid and N-hydroxysuccinimide (PAA-NHS). The negatively charged carboxyl groups effectively interact with the positively charged focal mucosa, and the NHS ester groups form the covalent bonds with the amino groups, thereby synergically enhancing the adhesion of the PLGA particles to the focal mucosa. Our findings reveal that, compared to the naked particles, the PAA-NHS coating increases the adhesion of particles to the inflammatory intestine. In a dextran sulfate sodium-induced acute colitis mouse model, the TAC/PLGA particles with PAA-NHS coating exhibits substantial retention of TAC within the inflammatory intestine, enhancing drug delivery efficiency and therapeutic effects. This approach holds promise for UC management, minimizing systemic side effects and optimizing therapeutic outcomes.

Recent advances in electrospray encapsulation of probiotics: influencing factors, natural polymers and emerging technologies

The probiotic food sector is rapidly growing due to increased consumer demand for nutritional supplements. However, ensuring probiotic viability within the harsh conditions of the gastrointestinal tract remains a major challenge. While probiotic encapsulation is a promising solution to enhance probiotic viability, most traditional encapsulation methods have significant limitations. This review underscores the significance of adopting novel encapsulation technologies, particularly electrospray (ES), which offers superior encapsulation efficiency and versatility. It begins with an introduction to the principles and classification of ES, analyzes factors influencing the properties of ES microcapsules, and reviews the use of natural polymers in ES-based encapsulation. Additionally, it discusses recent advancements in this field, focusing on improvements in ES equipment (e.g., coaxial ES and emulsion ES) and the integration of ES with other technologies (e.g., microfluidic ES and ES-fluidized bed coating). Finally, it highlights existing challenges and explores future prospects in this evolving field, offering valuable insights for advancing probiotic encapsulation technologies and enhancing public health outcomes.

Single-cell nanocapsules of gut microbiota facilitate fecal microbiota transplantation

Rationale: Fecal microbiota transplantation (FMT) is advantageous for treating intractable diseases via the microbiota-gut-organ axis. However, invasive administration of gut microbiota via nasal feeding tubes limits the widespread application of FMT. Here, we attempted to develop a novel strategy to deliver gut microbiota using nanocapsules. Methods: Single-cell nanocapsules were fabricated within 1 h by layer-by-layer assembly of silk fibroin and phosphatidylcholine to generate a protective nanoshell on the cell surface of complicated microbiota. The physical properties of the microbiota nanocapsules were analyzed. The protective effects of nanocapsules on the gastrointestinal tract were analyzed both in vitro and in vivo. The efficacy of FMT assisted by single-cell nanocapsules (NanoFMT) was evaluated using the inflammatory response, gut microbiota balance, and histopathological analysis in animal model. Results: The nanocapsules achieved a good coating ratio for a single type of microbe and complex microbiota, resulting in a remarkable increase in the survival rate of microbes in the gastrointestinal tract. NanoFMT improved the diversity and abundance of the gut microbiota better than common FMT in germ-free mice. Moreover, NanoFMT alleviated intestinal inflammation and positively reversed the microbiota balance in a mouse model of colitis compared with common FMT, assisted by the inherent anti-inflammatory effects of silk fibroin and phosphatidylcholine. Conclusions: Considering its rapid preparation, convenient delivery, and perfect therapeutic effect, we anticipate that NanoFMT may be a promising clinical candidate for next-generation FMT treatment.

Interaction between ischemia-reperfusion injury and intestinal microecology in organ transplantation and its therapeutic prospects

Organ transplantation is a vital intervention for end-stage organ failure; however, ischemia-reperfusion injury is a complication of transplantation, affecting the prognosis and survival of transplant recipients. As a complex ecosystem, recent research has highlighted the role of the intestinal microecology in transplantation, revealing its significant interplay with ischemia-reperfusion injury. This review explores the interaction between ischemia-reperfusion injury and intestinal microecology, with a special focus on how ischemia-reperfusion injury affects intestinal microecology and how these microecological changes contribute to complications after organ transplantation, such as infection and rejection. Based on a comprehensive analysis of current research advances, this study proposes potential strategies to improve transplant outcomes, offering guidance for future research and clinical practice.

Exploring the therapeutic potential of yeast β-glucan: Prebiotic, anti-infective, and anticancer properties - A review

Yeast β-glucan (YBG), an indigestible polysaccharide from yeast cell walls, is multifunctional. It plays a pivotal role in regulating gut microbiota (GM) and boosting the immune system, which is central to research on inflammation, cancer, and metabolic diseases. By modulating the GM, YBG exhibits various prebiotic effects, including hypoglycemic, hypolipidemic, and immune-regulating properties. Additionally, acting as a bioreactor modulator, it activates immune responses, demonstrating potential in anti-infection and anticancer applications. This article synthesizes the latest data from in vitro, in vivo, and clinical studies. It comprehensively evaluates the therapeutic potential of YBG, starting from its structure-function relationship. It particularly focuses on the application prospects of yeast β-glucan in probiotic-like effects, anti-infectious properties, and anti-cancer activity, and explores the underlying mechanisms of these actions. The aim of this article is to elucidate the positive impact of YBG on health by modulating the gut microbiota and enhancing immune responses. Simultaneously, it identifies critical areas for future research to provide theoretical support for its development in biomedical applications.

Micro/nanorobots for gastrointestinal tract

The application of micro/nanomotors (MNMs) in the gastrointestinal tract has become a Frontier in the treatment of gastrointestinal diseases. These miniature robots can enter the gastrointestinal tract through oral administration, achieving precise drug delivery and therapy. They can traverse mucosal layers and tissue barriers, directly targeting tumors or other lesion sites, thereby enhancing the bioavailability and therapeutic effects of drugs. Through the application of nanotechnology, these MNMs are able to accomplish targeted medication release, regulating drug release in response to either external stimuli or the local biological milieu. This results in reduced side effects and increased therapeutic efficacy. This review summarizes the primary classifications and power sources of current MNMs, as well as their applications in the gastrointestinal tract, providing inspiration and direction for the treatment of gastrointestinal diseases with MNMs.

Surface nanocoating of bacteria as a versatile platform to develop living therapeutics

Bacteria have been extensively utilized as living therapeutics for disease treatment due to their unique characteristics, such as genetic manipulability, rapid proliferation and specificity to target disease sites. Various in vivo insults can, however, decrease the vitality of dosed bacteria, leading to low overall bioavailability. Additionally, the innate antigens on the bacterial surface and the released toxins and metabolites may cause undesired safety issues. These limitations inevitably result in inadequate treatment outcomes, thereby hindering the clinical transformation of living bacterial therapeutics. Recently, we have developed a versatile platform to prepare advanced living bacterial therapeutics by nanocoating bacteria individually via either chemical decoration or physical encapsulation, which can improve bioavailability and reduce side effects for enhanced microbial therapy. Here we use interfacial self-assembly to prepare lipid membrane-coated bacteria (LCB), exhibiting increased resistance against a variety of harsh environmental conditions owing to the nanocoating's protective capability. Meanwhile, we apply mechanical extrusion to generate cell membrane-coated bacteria (CMCB), displaying improved biocompatibility owing to the nanocoating's shielding effect. We describe their detailed preparation procedures and demonstrate the expected functions of the coated bacteria. We also show that following oral delivery and intravenous injection in mouse models, LCB and CMCB present appealing potential for treating colitis and tumors, respectively. Compared with bioengineering that lacks versatile molecular tools for heterogeneous expression, the surface nanocoating technique is convenient to introduce functional components without restriction on bacterial strain types. Excluding bacterial culture, the fabrication of LCB takes ~2 h, while the preparation of CMCB takes ~5 h.

Dual-layer probiotic encapsulation using metal phenolic network with gellan gum-tamarind gum coating for colitis treatment

Probiotic oral therapy has been recognised as an effective treatment for inflammatory bowel disease (IBD). However, the efficacy of probiotics is often diminished due to their limited resistance to harsh gastrointestinal conditions. Therefore, the importance of designing innovative strategies for oral probiotic delivery for the effective treatment of IBD is increasingly recognised. In this study, we present a novel encapsulation strategy of Lactobacillus plantarum (L.P) using the dual-layer system consisting of a tannic acid‑calcium network and polysaccharide coating (gellan gum-tamarind gum) named L.P-C/T-G/T. This double-layer encapsulation system not only does not affect the normal proliferation of probiotics and provide protection, but also endows probiotics with more functions. More specifically, the acid resistance ability of the encapsulated probiotics is increased by 10 times, the free radical scavenging rate is enhanced by 5 times, and the intestinal retention time can be prolonged by 6-12 h. In the DSS-induced murine colitis model, it significantly alleviated colon shortening, inhibited ROS overexpression, and promoted the repair and regeneration of the mucus layer. This dual-layer encapsulation approach for a single probiotic demonstrates a significant advancement in probiotic delivery technology, offering hope for a comprehensive approach to the treatment of colitis and potentially other gastrointestinal disorders.

Design of probiotic delivery systems and their therapeutic effects on targeted tissues

The microbiota at different sites in the body is closely related to disease. The intake of probiotics is an effective strategy to alleviate diseases and be adjuvant in their treatment. However, probiotics may suffer from harsh environments and colonization resistance, making it difficult to maintain a sufficient number of live probiotics to reach the target sites and exert their original probiotic effects. Encapsulation of probiotics is an effective strategy. Therefore, probiotic delivery systems, as effective methods, have been continuously developed and innovated to ensure that probiotics are effectively delivered to the targeted site. In this review, initially, the design of probiotic delivery systems is reviewed from four aspects: probiotic characteristics, processing technologies, cell-derived wall materials, and interactions between wall materials. Subsequently, the review focuses on the effects of probiotic delivery systems that target four main microbial colonization sites: the oral cavity, skin, intestine, and vagina, as well as disease sites such as tumors. Finally, this review also discusses the safety concerns of probiotic delivery systems in the treatment of disease and the challenges and limitations of implementing this method in clinical studies. It is necessary to conduct more clinical studies to evaluate the effectiveness of different probiotic delivery systems in the treatment of diseases.

The dynamic crosslinking between gut microbiota and inflammation during aging: reviewing the nutritional and hormetic approaches against dysbiosis and inflammaging

The early-life gut microbiota (GM) is increasingly recognized for its contributions to human health and disease over time. Microbiota composition, influenced by factors like race, geography, lifestyle, and individual differences, is subject to change. The GM serves dual roles, defending against pathogens and shaping the host immune system. Disruptions in microbial composition can lead to immune dysregulation, impacting defense mechanisms. Additionally, GM aids digestion, releasing nutrients and influencing physiological systems like the liver, brain, and endocrine system through microbial metabolites. Dysbiosis disrupts intestinal homeostasis, contributing to age-related diseases. Recent studies are elucidating the bacterial species that characterize a healthy microbiota, defining what constitutes a 'healthy' colonic microbiota. The present review article focuses on the importance of microbiome composition for the development of homeostasis and the roles of GM during aging and the age-related diseases caused by the alteration in gut microbial communities. This article might also help the readers to find treatments targeting GM for the prevention of various diseases linked to it effectively.

Innovative Oral Nano/Gene Delivery System Based on Engineered Modified Saccharomyces cerevisiae for Colorectal Cancer Therapy

The efficient delivery of RNA-based drugs to solid tumors remains a formidable obstacle. We aim to develop a safe and efficient oral drug delivery system compatible with RNA-based drugs that is urgently needed to overcome challenges such as enzymatic degradation and gastrointestinal barriers to facilitate effective treatment for treating colorectal cancer (CRC). To address these challenges, we utilized engineered modified Saccharomyces cerevisiae to evaluate the delivery efficacy of miR21-antagomir for treating CRC in preclinical mouse models, including adenomatosis polyposis coli mutant transgenic mice ApcMin/+ and in situ tumor-bearing mice. An orally deliverable gene delivery system, YS@NPs21, was designed. This gene delivery system demonstrated effectively suppressed tumor growth in both ApcMin/+ and in situ tumor-bearing mice models. This system exhibited tumor-targeting capability, effective inhibition of tumor growth, and low toxicity toward nontumor cells. Successful implementation of this innovative oral drug delivery system could offer a straightforward, safe, and RNA drug-compatible approach to CRC treatment, ultimately improving patient outcomes and reducing medical costs.

Gastrointestinal Self-Adaptive and Nutrient Self-Sufficient Akkermansia muciniphila-Gelatin Porous Microgels for Synergistic Therapy of Ulcerative Colitis

To realize effective and long-term synergistic therapy of ulcerative colitis (UC) with probiotics, we developed gastrointestinal self-adaptive and nutrient self-sufficient Akkermansia muciniphila (AKK)-gelatin porous microgels (AKK@GPMGs). In AKK@GPMGs, AKK was covered with sequential layers of proanthocyanidins (PAs), mucin (MUC), and phosphatidylcholine (PC) to obtain AKK@PAs-MUC-PC (AKK@PMP), and then encapsulated within the methacrylate-modified gelatin porous microgels. AKK@GPMGs provide sufficient mucus as a nutrition source for AKK and boost resistance to stomach acid by 30.49-fold, and colonization in the intestines is enhanced by 83.46 times. The microgels can be dissociated by matrix metalloproteinase at the inflammatory sites of the intestine, and release AKK@PMP, which acts as "band-aid" that adheres to the inflamed colon for a long time and offers improved synergistic therapy for UC. Compared to uncoated AKK, AKK@GPMGs increase reactive oxygen species scavenging capacity by 26.47 times, improve the intestinal mucus layer thickness by 5.63 times, increase the goblet cells abundance by 3.93 times, reduce intestinal permeability by 5.60 times and significantly enhance beneficial gut microbiota while repressing harmful microbiota. These results indicate that AKK@GPMGs can restore mucus layer and tight junction integrity, reduce inflammation and oxidative stress, and regulate gut microbiota homeostasis to effectively treat intestinal inflammation.

Single-cell encapsulation systems for probiotic delivery: Armor probiotics

Functional foods or drugs based on probiotics have gained unprecedented attention and development due to the increasingly clear relationship between probiotics and human health. Probiotics can regulate intestinal microbiota, dynamically participating in various physiological activities to directly affect human health. Some probiotic-based functional preparations have shown great potential in treating multiple refractory diseases. Currently, the survival and activity of probiotic cells in complex environments in vitro and in vivo have taken priority, and various encapsulation systems based on food-derived materials have been designed and constructed to protect and deliver probiotics. However, traditional encapsulation technology cannot achieve precise protection for a single probiotic, which makes it unable to have a significant effect after release. In this case, single-cell encapsulation systems can be assembled based on biological interfaces to protect and functionalize individual probiotic cells, maximizing their physiological activity. This review discussed the arduous challenges of probiotics in food processing, storage, human digestion, and the commonly used probiotic encapsulation system. Besides, a novel technology of probiotic encapsulation was introduced based on single-cell coating, namely, "armor probiotics". We focused on the classification, structural design, and functional characteristics of armor coatings, and emphasized the essential functional characteristics of armor probiotics in human health regulation, including regulating intestinal health and targeted bioimaging and treatment of diseased tissues. Subsequently, the benefits, limitations, potential challenges, as well as future direction of armor probiotics were put forward. We hope this review may provide new insights and ideas for developing a single-cell probiotics encapsulating system.

Engineered probiotic ameliorates ulcerative colitis by restoring gut microbiota and redox homeostasis

Probiotics are potential treatments for ulcerative colitis (UC), but their efficacy is frequently compromised by gastrointestinal conditions that limit adhesion and activity. Here, we use machine learning and bioinformatics to confirm that patients with UC have decreased prevalence of Lactobacillus genus and increased oxidative stress, which correlate with inflammation severity. Accordingly, we developed a probiotic-based therapeutic that synergistically restores intestinal redox and microbiota homeostasis. Lactobacillus casei (Lac) were induced to form a pericellular film, providing a polysaccharide network for spatially confined crystallization of ultrasmall but highly active selenium dots (Se-Lac). Upon oral administration, the selenium dot-embedded pericellular film efficiently enhanced gastric acid resistance and intestinal mucoadhesion of Lac cells. At the lesion site, the selenium dots scavenged reactive oxygen species, while Lac modulated the gut microbiota. In multiple mouse models and non-human primates, this therapeutic effectively relieved inflammation and reduced colonic damage, thus showing promise as a UC treatment.

β-Glucan-A promising immunocyte-targeting drug delivery vehicle: Superiority, applications and future prospects

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, β-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, β-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of β-glucans applied in the drug delivery system including yeast β-glucan, Schizophyllan and curdlan, highlighting the benefits of β-glucan based delivery system. We summarize how β-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of β-glucan based delivery systems.

Understanding Mucosal Physiology and Rationale of Formulation Design for Improved Mucosal Immunity

The oral and nasal cavities serve as critical gateways for infectious pathogens, with microorganisms primarily gaining entry through these routes. Our first line of defense against these invaders is the mucosal membrane, a protective barrier that shields the body's internal systems from infection while also contributing to vital functions like air and nutrient intake. One of the key features of this mucosal barrier is its ability to protect the physiological system from pathogens. Additionally, mucosal tolerance plays a crucial role in maintaining homeostasis by regulating the pH and water balance within the body. Recognizing the importance of the mucosal barrier, researchers have developed various mucosal formulations to enhance the immune response. Mucosal vaccines, for example, deliver antigens directly to mucosal tissues, triggering local immune stimulation and ultimately inducing systemic immunity. Studies have shown that lipid-based formulations such as liposomes and virosomes can effectively elicit both local and systemic immune responses. Furthermore, mucoadhesive polymeric particles, with their prolonged delivery to target sites, have demonstrated an enhanced immune response. This Review delves into the critical role of material selection and delivery approaches in optimizing mucosal immunity.

Advanced Bioinspired Multifunctional Platforms Focusing on Gut Microbiota Regulation

Gut microbiota plays a crucial role in maintaining host homeostasis, impacting the progression and therapeutic outcomes of diseases, including inflammatory bowel disease, cancer, hepatic conditions, obesity, cardiovascular pathologies, and neurologic disorders, via immune, neural, and metabolic mechanisms. Hence, the gut microbiota is a promising target for disease therapy. The safety and precision of traditional microbiota regulation methods remain a challenge, which limits their widespread clinical application. This limitation has catalyzed a shift toward the development of multifunctional delivery systems that are predicated on microbiota modulation. Guided by bioinspired strategies, an extensive variety of naturally occurring materials and mechanisms have been emulated and harnessed for the construction of platforms aimed at the monitoring and modulation of gut microbiota. This review outlines the strategies and advantages of utilizing bioinspired principles in the design of gut microbiota intervention systems based on traditional regulation methods. Representative studies on the development of bioinspired therapeutic platforms are summarized, which are based on gut microbiota modulation to confer multiple pharmacological benefits for the synergistic management of diseases. The prospective avenues and inherent challenges associated with the adoption of bioinspired strategies in the refinement of gut microbiota modulation platforms are proposed to augment the efficacy of disease treatment.

Functional modification of gut bacteria for disease diagnosis and treatment

Intestinal bacteria help keep humans healthy by regulating lipid and glucose metabolism as well as the immunological and neurological systems. Oral treatment using intestinal bacteria is limited by the high acidity of stomach fluids and the immune system's attack on foreign bacteria. Scientists have created coatings and workarounds to overcome these limitations and improve bacterial therapy. These preparations have demonstrated promising outcomes, with advances in synthetic biology and optogenetics improving their focused colonization and controlled release. Engineering bacteria preparations have become a revolutionary therapeutic approach that converts intestinal bacteria into cellular factories for medicinal chemical synthesis. The present paper discusses various aspects of engineering bacteria preparations, including wrapping materials, biomedical uses, and future developments.

Target-Triggered Aggregation of Modified E. coli for Diagnosis of Ovarian Cancer

Bacteria inherently possess the capability of quorum sensing in response to the environment. In this work, we have proposed a strategy to confer bacteria with the ability to recognize targets with quorum-sensing behavior. Meanwhile, we have successfully achieved artificial control over the target-triggered aggregation of Escherichia coli (E. coli) by modifying the bacteria surface in a new way. Furthermore, by making use of green fluorescent protein (GFP) expressed by E. coli as the output signal, the aggregation of modified E. coli can be observed with the naked eye. Therefore, via the detection of the target, MUC1, an ovarian cancer biomarker, a simple and conveniently operated method to diagnose ovarian cancer is developed in this work. Experimental results show that the developed low-background and enzyme-free amplification method enables the highly sensitive detection of MUC1, achieving a remarkable limit of detection (LOD) of 5.47 fM and a linear detection range spanning from 1 pM to 50 nM and 50 nM to 100 nM, respectively. Clinical samples from healthy donors and patients can give distant assay results, showing great potential for clinical applications of this method.

Intestinal Delivery of Probiotics: Materials, Strategies, and Applications

Probiotics with diverse and crucial properties and functions have attracted broad interest from many researchers, who adopt intestinal delivery of probiotics to modulate the gut microbiota. However, the major problems faced for the therapeutic applications of probiotics are the viability and colonization of probiotics during their processing, oral intake, and subsequent delivery to the gut. The challenges of simple oral delivery (stability, controllability, targeting, etc.) have greatly limited the use of probiotics in clinical therapies. Nanotechnology can endow the probiotics to be delivered to the intestine with improved survival rate and increased resistance to the adverse environment. Additionally, the progress in synthetic biology has created new opportunities for efficiently and purposefully designing and manipulating the probiotics. In this article, a brief overview of the types of probiotics for intestinal delivery, the current progress of different probiotic encapsulation strategies, including the chemical, physical, and genetic strategies and their combinations, and the emerging single-cell encapsulation strategies using nanocoating methods, is presented. The action mechanisms of probiotics that are responsible for eliciting beneficial effects are also briefly discussed. Finally, the therapeutic applications of engineered probiotics are discussed, and the future trends toward developing engineered probiotics with advanced features and improved health benefits are proposed.

Dress me an outfit: advanced probiotics hybrid systems for intelligent IBD therapy

Inflammation bowel disease (IBD) has emerged as a public health challenge worldwide; with high incidence and rapid prevalence, it has troubled billions of people and further induced multitudinous systemic complications. Recent decade has witnessed the vigorous application of food-borne probiotics for IBD therapy; however, the complicated and changeable environments of digestive tract have forced probiotics to face multiple in vivo pressures, consequently causing unsatisfied prophylactic or therapeutic efficacy attributed to off-targeted arrival, damaged viability, insufficient colonization efficiency, etc. Fortunately, arisen hybrid technology has provided versatile breakthroughs for the targeted transplantation of probiotics. By ingeniously modifying probiotics to form probiotics hybrid systems (PHS), the biological behaviors of probiotics in vivo could be mediated, the interactions between probiotics with intestinal components can be facilitated, and diverse advanced probiotic-based therapies for IBD challenge can be developed, which attribute to the intelligent response to microenvironment of PHS, and intelligent design of PHS for multiple functions combination. In this review, various PHS were categorized and their intestinal behaviors were elucidated systematically, their therapeutic effects and intrinsic mechanism were further analyzed. Besides, shortages of present PHS and the corresponding solutions have been discussed, based on which the future perspectives of this field have also been proposed. The undeniable fact is that PHS show an incomparable future to bring the next generation of advanced food science.

Reinforcement of the intestinal mucosal barrier via mucus-penetrating PEGylated bacteria

The breakdown of the gut's mucosal barrier that prevents the infiltration of microorganisms, inflammatory cytokines and toxins into bodily tissues can lead to inflammatory bowel disease and to metabolic and autoimmune diseases. Here we show that the intestinal mucosal barrier can be reinforced via the oral administration of commensal bacteria coated with poly(ethylene glycol) (PEG) to facilitate their penetration into mucus. In mice with intestinal homoeostatic imbalance, mucus-penetrating PEGylated bacteria preferentially localized in mucus at the lower gastrointestinal tract, inhibited the invasion of pathogenic bacteria, maintained homoeostasis of the gut microbiota, stimulated the secretion of mucus and the expression of tight junctions, and prevented the mice from developing colitis and diabetes. Orally delivered PEGylated bacteria may help prevent and treat gastrointestinal disorders.

Novel strategies for modulating the gut microbiome for cancer therapy

Recent advancements in genomics, transcriptomics, and metabolomics have significantly advanced our understanding of the human gut microbiome and its impact on the efficacy and toxicity of anti-cancer therapeutics, including chemotherapy, immunotherapy, and radiotherapy. In particular, prebiotics, probiotics, and postbiotics are recognized for their unique properties in modulating the gut microbiota, maintaining the intestinal barrier, and regulating immune cells, thus emerging as new cancer treatment modalities. However, clinical translation of microbiome-based therapy is still in its early stages, facing challenges to overcome physicochemical and biological barriers of the gastrointestinal tract, enhance target-specific delivery, and improve drug bioavailability. This review aims to highlight the impact of prebiotics, probiotics, and postbiotics on the gut microbiome and their efficacy as cancer treatment modalities. Additionally, we summarize recent innovative engineering strategies designed to overcome challenges associated with oral administration of anti-cancer treatments. Moreover, we will explore the potential benefits of engineered gut microbiome-modulating approaches in ameliorating the side effects of immunotherapy and chemotherapy.

Peyer's Patch: Possible target for modulating the Gut-Brain-Axis through microbiota

The gastrointestinal (GI) tract and the brain form bidirectional nervous, immune, and endocrine communications known as the gut-brain axis. Several factors can affect this axis; among them, various studies have focused on the microbiota and imply that alterations in microbiota combinations can influence both the brain and GI. Also, many studies have shown that the immune system has a vital role in varying gut microbiota combinations. In the current paper, we will review the multidirectional effects of gut microbiota, immune system, and nervous system on each other. Specifically, this review mainly focuses on the impact of Peyer's patches as a critical component of the gut immune system on the gut-brain axis through affecting the gut's microbial composition. In this way, some factors were discussed as proposed elements of missing gaps in this field.

Intestinal Colonized Silkworm Chrysalis-Like Probiotic Composites for Multi-Crossed Comprehensive Synergistic Therapy of Inflammatory Bowel Disease

Inspired by the timely emergence of silkworm pupae from their cocoons, silkworm chrysalis-like probiotic composites (SCPCs) are developed for the comprehensive therapy of inflammatory bowel disease (IBD), in which probiotics are enveloped as the "pupa" in a sequential layering of silk sericin (SS), tannic acid (TA), and polydopamine, akin to the protective "cocoon". Compared to unwrapped probiotics, these composites not only demonstrate exceptional resistance to the harsh gastrointestinal environment and exhibit over 200 times greater intestinal colonization but also safeguard probiotics from the damage of IBD environment while enabling probiotics sustained release. The probiotics, in synergy with SS and TA, provide a multi-crossed comprehensive therapy for IBD that simultaneously addresses various pathological features of IBD, including intestinal barrier disruption, elevated pro-inflammatory cytokines, heightened oxidative stress, and disturbances in the intestinal microbiota. SCPCs exhibit remarkable outcomes, including a 9.7-fold reduction in intestinal permeability, an 8.9-fold decrease in IL-6 levels, and a 2.9-fold reduction in TNF-α levels compared to uncoated probiotics. Furthermore, SCPCs demonstrate an impressive 92.25% reactive oxygen species clearance rate, significantly enhance the richness of beneficial intestinal probiotics, and effectively diminish the abundance of pathogenic bacteria, indicating a substantial improvement in the overall therapeutic effect of IBD.

Current research progress, opportunities, and challenges of Limosillactobacillus reuteri-based probiotic dietary strategies

Limosillactobacillus reuteri (L. reuteri), a type of Lactobacillus spp., stands out as the most extensively researched probiotic. Its remarkable intestinal adhesion has led to widespread applications in both the food and medical sectors. Notably, recent research highlights the probiotic efficacy of L. reuteri sourced from breast milk, particularly in influencing social behavior and mitigating atopic dermatitis. In this review, our emphasis is on surveying recent literature regarding the promotion of host's health by L. reuteri. We aim to provide a concise summary of the latest regulatory effects and potential mechanisms attributed to L. reuteri in the realms of metabolism, brain- and immune-related functions. The mechanism through which L. reuteri promotes host health by modulating the intestinal microenvironment primarily involves promoting intestinal epithelial renewal, bolstering intestinal barrier function, regulating gut microbiota and its metabolites, and suppressing inflammation and immune responses. Additionally, this review delves into new technologies, identifies shortcomings, and addresses challenges in current L. reuteri research. Finally, the application prospects of L. reuteri are provided. Therefore, a better understanding of the role and mechanisms of L. reuteri will contribute significantly to the development of new probiotic functional foods and enable precise, targeted interventions for various diseases.

ATP-Responsive Manganese-Based Bacterial Materials Synergistically Activate the cGAS-STING Pathway for Tumor Immunotherapy

Stimulating the cyclic guanosine monophophate(GMP)-adenosine monophosphate (AMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway is a crucial strategy by which bacteria activate the tumor immune system. However, the limited stimulation capability poses significant challenges in advancing bacterial immunotherapy. Here, an adenosine 5'-triphosphate (ATP)-responsive manganese (Mn)-based bacterial material (E. coli@PDMC-PEG (polyethylene glycol)) is engineered successfully, which exhibits an exceptional ability to synergistically activate the cGAS-STING pathway. In the tumor microenvironment, which is characterized by elevated ATP levels, this biohybrid material degrades, resulting in the release of divalent manganese ions (Mn2+) and subsequent bacteria exposure. This combination synergistically activates the cGAS-STING pathway, as Mn2+ enhances the sensitivity of cGAS to the extracellular DNA (eDNA) secreted by the bacteria. The results of the in vivo experiments demonstrate that the biohybrid materials E. coli@PDMC-PEG and VNP20009@PDMC-PEG effectively inhibit the growth of subcutaneous melanoma in mice and in situ liver cancer in rabbits. Valuable insights for the development of bacteria-based tumor immunotherapy are provided here.

Efficient enzyme-free method to assess the development and maturation of the innate and adaptive immune systems in the mouse colon

Researchers who aim to globally analyze the gastrointestinal immune system via flow cytometry have many protocol options to choose from, with specifics generally tied to gut wall layers of interest. To get a clearer idea of the approach we should use on full-thickness colon samples from mice, we first undertook a systematic comparison of three tissue dissociation techniques: two based on enzymatic cocktails and the other one based on manual crushing. Using flow cytometry panels of general markers of lymphoid and myeloid cells, we found that the presence of cell-surface markers and relative cell population frequencies were more stable with the mechanical method. Both enzymatic approaches were associated with a marked decrease of several cell-surface markers. Using mechanical dissociation, we then developed two minimally overlapping panels, consisting of a total of 26 antibodies, for serial profiling of lymphoid and myeloid lineages from the mouse colon in greater detail. Here, we highlight how we accurately delineate these populations by manual gating, as well as the reproducibility of our panels on mouse spleen and whole blood. As a proof-of-principle of the usefulness of our general approach, we also report segment- and life stage-specific patterns of immune cell profiles in the colon. Overall, our data indicate that mechanical dissociation is more suitable and efficient than enzymatic methods for recovering immune cells from all colon layers at once. Additionally, our panels will provide researchers with a relatively simple tool for detailed immune cell profiling in the murine gastrointestinal tract, regardless of life stage or experimental conditions.

Enzyme-like biomimetic oral-agent enabling modulating gut microbiota and restoring redox homeostasis to treat inflammatory bowel disease

Reactive oxygen species (ROS), immune dysregulation-induced inflammatory outbreaks and microbial imbalance play critical roles in the development of inflammatory bowel disease (IBD). Herein, a novel enzyme-like biomimetic oral-agent ZnPBA@YCW has been developed, using yeast cell wall (YCW) as the outer shell and zinc-doped Prussian blue analogue (ZnPBA) nanozyme inside. When orally administered, the ZnPBA@YCW is able to adhere to Escherichia coli occupying the ecological niche in IBD and subsequently release the ZnPBA nanozyme for removal of E. coli, meanwhile exhibiting improved intestinal epithelial barrier repair. Moreover, it is found that the ZnPBA nanozyme exhibits remarkable capability in restoring redox homeostasis by scavenging ROS and inhibiting NF-κB signaling pathway. More importantly, the 16S ribosomal RNA gene sequencing results indicate that post-oral of ZnPBA@YCW can effectively regulate gut microbiota by enhancing the bacterial richness and diversity, significantly increasing the abundance of probiotics with anti-inflammatory phenotype while downgrading pathogenic E. coli to the same level as normal mice. Such a novel nanomedicine provides a new idea for efficient treating those ROS-mediated diseases accompanying with flora disorders.

Oral delivery of probiotics using single-cell encapsulation

Adequate intake of live probiotics is beneficial to human health and wellbeing because they can help treat or prevent a variety of health conditions. However, the viability of probiotics is reduced by the harsh environments they experience during passage through the human gastrointestinal tract (GIT). Consequently, the oral delivery of viable probiotics is a significant challenge. Probiotic encapsulation provides a potential solution to this problem. However, the production methods used to create conventional encapsulation technologies often damage probiotics. Moreover, the delivery systems produced often do not have the required physicochemical attributes or robustness for food applications. Single-cell encapsulation is based on forming a protective coating around a single probiotic cell. These coatings may be biofilms or biopolymer layers designed to protect the probiotic from the harsh gastrointestinal environment, enhance their colonization, and introduce additional beneficial functions. This article reviews the factors affecting the oral delivery of probiotics, analyses the shortcomings of existing encapsulation technologies, and highlights the potential advantages of single-cell encapsulation. It also reviews the various approaches available for single-cell encapsulation of probiotics, including their implementation and the characteristics of the delivery systems they produce. In addition, the mechanisms by which single-cell encapsulation can improve the oral bioavailability and health benefits of probiotics are described. Moreover, the benefits, limitations, and safety issues of probiotic single-cell encapsulation technology for applications in food and beverages are analyzed. Finally, future directions and potential challenges to the widespread adoption of single-cell encapsulation of probiotics are highlighted.

Mechanoelectronic stimulation of autologous extracellular vesicle biosynthesis implant for gut microbiota modulation

Pathogenic gut microbiota is responsible for a few debilitating gastrointestinal diseases. While the host immune cells do produce extracellular vesicles to counteract some deleterious effects of the microbiota, the extracellular vesicles are of insufficient doses and at unreliable exposure times. Here we use mechanical stimulation of hydrogel-embedded macrophage in a bioelectronic controller that on demand boost production of up to 20 times of therapeutic extracellular vesicles to ameliorate the microbes' deleterious effects in vivo. Our miniaturized wireless bioelectronic system termed inducible mechanical activation for in-situ and sustainable generating extracellular vesicles (iMASSAGE), leverages on wireless electronics and responsive hydrogel to impose mechanical forces on macrophages to produce extracellular vesicles that rectify gut microbiome dysbiosis and ameliorate colitis. This in vivo controllable extracellular vesicles-produced system holds promise as platform to treat various other diseases.

Intestinal Mucosal Immune Barrier: A Powerful Firewall Against Severe Acute Pancreatitis-Associated Acute Lung Injury via the Gut-Lung Axis

The pathogenesis of severe acute pancreatitis-associated acute lung injury (SAP-ALI), which is the leading cause of mortality among hospitalized patients in the intensive care unit, remains incompletely elucidated. The intestinal mucosal immune barrier is a crucial component of the intestinal epithelial barrier, and its aberrant activation contributes to the induction of sustained pro-inflammatory immune responses, paradoxical intercellular communication, and bacterial translocation. In this review, we firstly provide a comprehensive overview of the composition of the intestinal mucosal immune barrier and its pivotal roles in the pathogenesis of SAP-ALI. Secondly, the mechanisms of its crosstalk with gut microbiota, which is called gut-lung axis, and its effect on SAP-ALI were summarized. Finally, a number of drugs that could enhance the intestinal mucosal immune barrier and exhibit potential anti-SAP-ALI activities were presented, including probiotics, glutamine, enteral nutrition, and traditional Chinese medicine (TCM). The aim is to offer a theoretical framework based on the perspective of the intestinal mucosal immune barrier to protect against SAP-ALI.

Promising dawn in tumor microenvironment therapy: engineering oral bacteria

Despite decades of research, cancer continues to be a major global health concern. The human mouth appears to be a multiplicity of local environments communicating with other organs and causing diseases via microbes. Nowadays, the role of oral microbes in the development and progression of cancer has received increasing scrutiny. At the same time, bioengineering technology and nanotechnology is growing rapidly, in which the physiological activities of natural bacteria are modified to improve the therapeutic efficiency of cancers. These engineered bacteria were transformed to achieve directed genetic reprogramming, selective functional reorganization and precise control. In contrast to endotoxins produced by typical genetically modified bacteria, oral flora exhibits favorable biosafety characteristics. To outline the current cognitions upon oral microbes, engineered microbes and human cancers, related literatures were searched and reviewed based on the PubMed database. We focused on a number of oral microbes and related mechanisms associated with the tumor microenvironment, which involve in cancer occurrence and development. Whether engineering oral bacteria can be a possible application of cancer therapy is worth consideration. A deeper understanding of the relationship between engineered oral bacteria and cancer therapy may enhance our knowledge of tumor pathogenesis thus providing new insights and strategies for cancer prevention and treatment.

Carboxymethylated Abrus cantoniensis polysaccharide prevents CTX-induced immunosuppression and intestinal damage by regulating intestinal flora and butyric acid content

As a Chinese folk health product, Abrus cantoniensis exhibits good immunomodulatory activity because of its polysaccharide components (ACP), and carboxymethylation of polysaccharides can often further improve the biological activity of polysaccharides. In this study, we explored the impact of prophylactic administration of carboxymethylated Abrus cantoniensis polysaccharide (CM-ACP) on immunosuppression and intestinal damage induced by cyclophosphamide (CTX) in mice. Our findings demonstrated that CM-ACP exhibited a more potent immunomodulatory activity compared to ACP. Additionally, CM-ACP effectively enhanced the abundance of short-chain fatty acid (SCFA)-producing bacteria in immunosuppressed mice and regulated the gene expression of STAT6 and STAT3 mediated pathway signals. In order to further explore the relationship among polysaccharides, intestinal immunity and intestinal flora, we performed a pseudo-sterile mouse validation experiment and fecal microbiota transplantation (FMT) experiment. The findings suggest that CM-FMT and butyrate attenuate CTX-induced immunosuppression and intestinal injury. CM-FMT and butyrate show superior immunomodulatory ability, and may effectively regulate intestinal cell metabolism and repair the damaged intestine by activating STAT6 and STAT3-mediated pathways. These findings offer new insights into the mechanisms by which CM-ACP functions as functional food or drug, facilitating immune response regulation and maintaining intestinal health.

Recombinant L. lactis vaccine LL-plSAM-WAE targeting four virulence factors provides mucosal immunity against H. pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) causes chronic gastric disease. An efficient oral vaccine would be mucosa-targeted and offer defense against colonization of invasive infection in the digestive system. Proteolytic enzymes and acidic environment in the gastrointestinal tract (GT) can, however, reduce the effectiveness of oral vaccinations. For the creation of an edible vaccine, L. lactis has been proposed as a means of delivering vaccine antigens.

RESULTS

We developed a plSAM (pNZ8148-SAM) that expresses a multiepitope vaccine antigen SAM-WAE containing Urease, HpaA, HSP60, and NAP extracellularly (named LL-plSAM-WAE) to increase the efficacy of oral vaccinations. We then investigated the immunogenicity of LL-plSAM-WAE in Balb/c mice. Mice that received LL-plSAM-WAE or SAM-WAE with adjuvant showed increased levels of antibodies against H. pylori, including IgG and sIgA, and resulted in significant reductions in H. pylori colonization. Furthermore, we show that SAM-WAE and LL-plSAM-WAE improved the capacity to target the vaccine to M cells.

CONCLUSIONS

These findings suggest that recombinant L. lactis could be a promising oral mucosa vaccination for preventing H. pylori infection.