Bacillus subtilis BN strain promotes Th1 response via Toll-like receptor 2 in polarized mouse M1 macrophage

Redefining Cell Culture Using a 3D Flipwell Co-culture System: A Mimetic for Gut Architecture and Dynamics In Vitro

Gut mucosae are composed of stratified layers of microbes, a selectively permeable mucus, an epithelial lining, and connective tissue homing immune cells. Studying cellular and chemical interactions between the gut mucosal components has been limited without a good model system. We have engineered a three-dimensional (3D) multi-cellular co-culture system we coined "3D Flipwell system" using cell culture inserts stacked against each other. This system allows an assessment of the impact of a gut mucosal environmental change on interactions between gut bacteria, epithelia, and immune cells. As such, this system can be utilized in examining the effects of exogenous stimuli, such as dietary nutrients, bacterial infection, and drugs, on the gut mucosa that could predetermine how these stimuli might influence the rest of body. Here, we describe the methods of construction and application of the new 3D Flipwell system we utilized previously in assessing the crosstalk between the gut mucosa and macrophage polarization. We demonstrate the physiological responses of different components of the co-cultures to Sepiapterin (SEP), the precursor of the nitric oxide synthase cofactor tetrahydrobiopterin (BH4). We reported previously that SEP induces a pro-immunogenic shift of macrophages having acquired an immune suppressive phenotype. We also showed that SEP induces a defense mechanism of commensal gut bacteria. The protocol describing the assembly and use of the 3D Flipwell co-culture system herein would grant its utility in evaluating the concurrent effects of pharmacologic and microbiologic stimuli on gut mucosal components. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: 3D Flipwell construction, assembly, and collagen coating Basic Protocol 2: Flipwell cell seeding and cell culture Basic Protocol 3: Addition of bacterial culture to the Flipwell system Basic Protocol 4: Flipwell disassembly for scanning electron microscopy (SEM) studies Basic Protocol 5: Immunofluorescence antibody staining for confocal microscopy.

Levilactobacillus brevis IBARAKI-TS3 Isolated From Pickles Promotes Production of Interleukin-10 via Toll-Like Receptor 2 in Human M2 Macrophages

M2 macrophages play an important role in food allergy. Several studies have reported that lactic acid bacteria isolated from pickles exert antiallergic effects. We investigated the effects of several strains of lactic acid bacteria on the immune function of M2 macrophages. M2 macrophages differentiated from THP-1 cell line by interleukin-4 (IL-4) and IL-13 strongly expressed CD163, CD206, and HMOX1 mRNA. Levilactobacillus brevis IBARAKI-TS3 (IBARAKI-TS3) isolated from pickles was identified as a lactic acid bacterium that enhances the expressions of IL-10 and EBI3 mRNA in M2 macrophages. IBARAKI-TS3 induced the expression of genes involved in Toll-like receptor (TLR) signaling, such as IRAK, mitogen-activated protein kinases (MAPKs), and NF-κB mRNA. IBARAKI-TS3-induced IL-10 production was suppressed by anti-TLR2-neutralizing antibodies. Furthermore, the IBARAKI-TS3-induced increase in IL-10 levels was significantly reduced in TLR2-knockdown M2 macrophages compared to M2 macrophages. These results suggest that IBARAKI-TS3 promotes of IL-10 production via TLR2 in M2 macrophages.

Surface Display of Duck Hepatitis A Virus Type 1 VP1 Protein on Bacillus subtilis Spores Elicits Specific Systemic and Mucosal Immune Responses on Mice

Duck viral hepatitis, primarily caused by duck hepatitis A virus type 1 (DHAV-1), poses a significant threat to the global duck industry. Bacillus subtilis is commonly utilized as a safe probiotic in the development of mucosal vaccines. In this study, a recombinant strain of B. subtilis, designated as B. subtilis RV, was constructed to display the DHAV-1 capsid protein VP1 on its spore surface using the outer coat protein B as an anchoring agent. The immunogenicity of this recombinant strain was evaluated in a mouse model through mixed feeding immunization. The results indicated that B. subtilis RV could elicit specific systemic and mucosal immune responses in mice, as evidenced by the high levels of serum IgG, intestinal secretory IgA, and potent virus-neutralizing antibodies produced. Furthermore, the recombinant strain significantly upregulated the expression levels of IL-2, IL-6, IL-10, TNF-α, and IFN-γ in the intestinal mucosa. Thus, the recombinant strain maintained the balance of the Th1/Th2 immune response and demonstrated an excellent mucosal immune adjuvant function. In summary, this study suggests that B. subtilis RV can be a novel alternative for effectively controlling DHAV-1 infection as a vaccine-based feed additive.

Biological Activities and Nanoparticle Synthesis of Dioscorea bulbifera and its Mechanistic Action - An Extensive Review

BACKGROUND

Dioscorea bulbifera is commonly known as air potato present in the tropical and subtropical regions. It is a perennial climber traditionally used for various therapeutic purposes by traditional healers. This review explores various medicinal uses of D. bulbifera and its active ingredients, as well as describes its nanoparticle synthesis for medical applications.

METHODS

The Google Scholar search engine was used to conduct this comprehensive review along with the databases of the following publishers: Elsevier, Springer, Taylor and Francis, Bentham, and PubMed.

DISCUSSION

D. bulbifera contains several bioactive compounds that are responsible for its pharmacological properties, such as antioxidant, anti-inflammatory, neuroprotective, anticancer, and antidiabetic properties. It is also used as a nutritive functional food. D. bulbifera-mediated nanoparticle synthesis has been established by the scientific communities for various medicinal applications.

CONCLUSION

D. bulbifera contains numerous active ingredients, including diosbulbins, bafoudiosbulbin, β-sitosterol, diosgenin, dioscin, pennogenin, myricetin, quercetin, and stigmasterols with numerous biological activities. In addition, it has a vital role in synthesizing nanoparticles with good pharmacological applications, especially in drug delivery systems. However, its potential characteristic features and functional properties of the active molecules present in this tuber need to be further explored in clinical trials. We suggest that using this edible tuber, we may formulate the valueadded food with good medicinal applications.

Novel 3D Flipwell system that models gut mucosal microenvironment for studying interactions between gut microbiota, epithelia and immunity

Gut mucosa consists of stratified layers of microbes, semi-permeable mucus, epithelium and stroma abundant in immune cells. Although tightly regulated, interactions between gut commensals and immune cells play indispensable roles in homeostasis and cancer pathogenesis in the body. Thus, there is a critical need to develop a robust model for the gut mucosal microenvironment. Here, we report our novel co-culture utilizing 3D Flipwell system for establishing the stratified layers of discrete mucosal components. This method allows for analyzing synchronous effects of test stimuli on gut bacteria, mucus, epithelium and immune cells, as well as their crosstalks. In the present report, we tested the immuno-stimulatory effects of sepiapterin (SEP, the precursor of the cofactor of nitric oxide synthase (NOS)-BH₄) on the gut mucosal community. We previously reported that SEP effectively reprogrammed tumor-associated macrophages and inhibited breast tumor cell growth. In our co-cultures, SEP largely promoted mucus integrity, bacterial binding, and M1-like polarization of macrophages. Conversely, these phenomena were absent in control-treated cultures. Our results demonstrate that this novel co-culture may serve as a robust in vitro system to recapitulate the effects of pharmacological agents on the gut mucosal microenvironment, and could potentially be expanded to test the effects outside the gut.

Effects of Bacillus subtilis Natto Strains on Antiviral Responses in Resiquimod-Stimulated Human M1-Phenotype Macrophages

Bacillus subtilis natto is used in the production of natto, a traditional fermented soy food, and has beneficial immunomodulatory effects in humans. Single-stranded RNA (ssRNA) viruses, including influenza and coronavirus, often cause global pandemics. We proposed a human cell culture model mimicking ssRNA viral infection and investigated the ability of B. subtilis natto to induce antiviral effects in the model. The gene expressions were analyzed using quantitative real-time reverse transcription PCR. M1-phenotype macrophages derived from THP-1 cells strongly express the Toll-like receptor 8 (76.2-hold), CD80 (64.2-hold), and CCR7 (45.7-hold) mRNA compared to M0 macrophages. One µg/mL of resiquimod (RSQ)-stimulation induced the expression of IRF3 (1.9-hold), CXCL10 (14.5-hold), IFNβ1 (3.5-hold), ISG20 (4.4-hold), and MxA (1.7-hold) mRNA in the M1-phenotype macrophages. Based on these results, the RSQ-stimulated M1-phenotype macrophages were used as a cell culture model mimicking ssRNA viral infection. Moreover, the B. subtilis natto XF36 strain induced the expression of genes associated with antiviral activities (IFNβ1, IFNλ1, ISG20, and RNase L) and anti-inflammatory activities (IL-10) in the cell culture model. Thus, it is suggested that the XF36 suppresses viral infections and excessive inflammation by inducing the expression of genes involved in antiviral and anti-inflammatory activities.

Fermented food: Should patients with cardiometabolic diseases go back to an early neolithic diet?

Fermentation has been used since the Early Neolithic period to preserve foods. It has inherent organoleptic and nutritive properties that bestow health benefits, including reducing inflammation and oxidative stress, supporting the growth of salutogenic microbiota, enhancing intestinal mucosal protection and promoting beneficial immunometabolic health effects. The fermentation of food with specific microbiota increases the production salutogenic bioactive compounds that can activate Nrf2 mediated cytoprotective responses and mitigate the effects of the 'diseasome of aging' and its associated inflammageing, which presents as a prominent feature of obesity, type-2 diabetes, cardiovascular and chronic kidney disease. This review discusses the importance of fermented food in improving health span, with special reference to cardiometabolic diseases.