Alterations in Faecal Microbiota and Elevated Levels of Intestinal IgA Following Oral Administration of Lacticaseibacillus casei in mice

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.

Lacticaseibacillus casei IB1 Alleviates DSS-Induced Inflammatory Bowel Disease by Regulating the Microbiota and Restoring the Intestinal Epithelial Barrier

Inflammatory bowel disease (IBD) is becoming an increasingly serious health problem in humans and animals. Probiotics can inhibit the development of IBD. Due to the specificity of the strains, the function and mechanism of action of different strains are still unclear. Here, a DSS-induced colitis mouse model was utilized to investigate the ability and mechanism by which Lacticaseibacillus casei IB1 alleviates colitis. Treatment with L. casei IB1 improved DSS-induced colitis in mice, as indicated by increased body weight, colon length, and goblet cell numbers and decreased disease activity index (DAI), proinflammatory factor (TNF-α, IL-1β, and IL-6) levels, and histopathological scores after intake of IB1. IB1 supplementation also improved the expression of tight junction proteins and inhibited the activation of the MAPK and NF-κB signaling pathways to alleviate intestinal inflammation. In addition, IB1 rebalanced the intestinal microbial composition of colitis mice by increasing the abundance of Faecalibaculum and Alistipes and decreasing the abundance of Bacteroides and Escherichia_Shigella. In summary, L. casei IB1 showed great potential for relieving colitis by regulating the microbiota and restoring the epithelial barrier. It can be used as a potential probiotic for the prevention and treatment of UC in the future.

The role of the glycome in symbiotic host-microbe interactions

Glycosylation plays a crucial role in many aspects of cell biology, including cellular and organismal integrity, structure-and-function of many glycosylated molecules in the cell, signal transduction, development, cancer, and in a number of diseases. Besides, at the inter-organismal level of interaction, a variety of glycosylated molecules are involved in the host-microbiota recognition and initiation of downstream signalling cascades depending on the outcomes of the glycome-mediated ascertainment. The role of glycosylation in host-microbe interactions is better elaborated within the context of virulence and pathogenicity in bacterial infection processes but the symbiotic host-microbe relationships also involve substantive glycome-mediated interactions. The works in the latter field have been reviewed to a much lesser extent, and the main aim of this mini-review is to compensate for this deficiency and summarise the role of glycomics in host-microbe symbiotic interactions.

Probiotic Debaryomyces hansenii CBS 8339 yeast enhanced immune responses in mice

This study aimed to examine the effect of Debaryomyces hansenii CBS 8339 on innate immune responses in mice. Thirty BALB/c mice were randomly treated with phosphate buffered saline (PBS) (control) and two D. hansenii (Dh) doses: Dh 10ˆ6 CFU (colony forming units) and Dh 10ˆ8 CFU daily for 15 days. Spleen, blood, and gut samples were taken on days 7 and 15. Mouse splenocytes were isolated and challenged with Escherichia coli. Immunological assays and immune-related gene expressions were performed. Serum was obtained from blood for total IgA and IgG antibody titer determination. Gut samples were taken for yeast colonization assessment. Phagocytosis, respiratory burst activity, and nitric oxide production in mice were mainly enhanced (p < 0.05) upon 7 days of D. hansenii intake at a concentration of 10ˆ8 CFU before and after bacterial challenge. Moreover, oral D. hansenii in mice upregulated (p < 0.05) gene expression of pro-inflammatory cytokines (INF-γ, IL-6 and IL-1β) before or after E. coli challenge on day 7 but downregulated (p < 0.05) on day 15. Furthermore, total serum IgG and IgA titers were higher (p < 0.05) in Dh 10ˆ8 CFU at days 7 and 15, and only at day 7, respectively, than that in the other dose and control groups. Finally, D. hansenii was detected in the gut of mice that received the treatments, suggesting that yeast survived gastrointestinal transit. Altogether, a short period (7 days) of D. hansenii CBS 8339 oral delivery improved immune innate response on mice.

Dietary Supplementation of Limosilactobacillus mucosae LM1 Enhances Immune Functions and Modulates Gut Microbiota Without Affecting the Growth Performance of Growing Pigs

Limosilactobacillus mucosae LM1 (LM1) is previously isolated from the intestine of piglets, but its potential as a probiotic supplement has not yet been assessed in growing pigs. In this study, we analyzed the probiotic effect of LM1 on the growth performance, apparent total tract digestibility (ATTD) of nutrients, immune properties, intestinal morphology, and gut microbiota and their metabolites in growing pigs. The experiment included 145 Duroc × (Landrace × Yorkshire) pigs (average body weight: 21.21 ± 1.14 kg) distributed into five treatment groups. The pigs were fed either a control diet (CON), or the control diet supplemented with incremental doses of LM1, namely low-dose LM1 (LL, 8.3 × 108 CFU/kg), moderate-low dose LM1 (ML, 4.2 × 109 CFU/kg), moderate-high dose LM1 (MH, 8.3 × 109 CFU/kg), and high-dose LM1 (HH, 2.1 × 1010 CFU/kg) for 42 d. On d 42, 12 pigs from each of the CON and MH groups were slaughtered. The results indicated that the ATTD of nitrogen (N, P = 0.038) was improved with MH supplementation. In addition, increasing dose of LM1 improved the immune response in pigs by reducing serum pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-alpha) and increasing anti-inflammatory cytokines (interleukin-10). Pigs fed with MH LM1 also had higher jejunal villus height and ileal villus height: crypt depth ratio, demonstrating improved intestinal morphology. Moreover, moderate-high LM1 supplementation enriched SCFA-producing taxa such as Lactobacillus, Holdemanella, Peptococcus, Bifidobacterium, Eubacterium_hallii_group, and Lachnospiraceae_AC2044_group, which correlated positively with increased fecal levels of butyrate and iso-valerate. These results strongly suggest the probiotic potential of LM1 on growing pigs. Overall, the current study provides insights on the use of L. mucosae LM1 as a novel livestock probiotic to improve pig gut health.

Gut Microbes in Immunoglobulin A Nephropathy and Their Potential Therapeutic Applications

Microbial ecosystem consists of a complex community of bacterial interactions and its host microenvironment (tissue, cell, metabolite). Because the interaction between gut microbiota and host involves many diseases and seriously affects human health, the study of the interaction mechanism between gut microbiota and host has attracted great attention. The gut microbiome is made up of 100 trillion bacteria that have both beneficial and adverse effects on human health. The development of IgA Nephropathy results in changes in the intestinal microbial ecosystem that affect host physiology and health. Similarly, changes in intestinal microbiota also affect the development of IgA Nephropathy. Thus, the gut microbiome represents a novel therapeutic target for improving the outcome of IgA Nephropathy, including hematuria symptoms and disease progression. In this review, we summarize the effect of intestinal microbiota on IgA Nephropathy in recent years and it has been clarified that the intestinal microbiota has a great influence on the pathogenesis and treatment of IgA Nephropathy.

Lactiplantibacillus plantarum inhibits colon cancer cell proliferation as function of its butyrogenic capability

Lactobacilli have been shown to inhibit or suppress cancer cell growth through the release of strain-specific bioactive metabolites and their inclusion in functional foods could exert a health promoting activity on human health. Herein, we examined the antiproliferative activity of the Lactiplantibacillus plantarum strains S2T10D and O2T60C, which have been previously shown to exert different butyrogenic activities. Human HT-29 cells were employed as an in vitro colon cancer model and both bacterial strains were found to inhibit their growth. However, the strain S2T10D showed a greater antiproliferative activity which, interestingly, was correlated to its butyrogenic capability. Noteworthy, for the non-butyrogenic strain O2T60C, the growth inhibitory capability was rather limited. Furthermore, both the butyrate-containing supernatant of S2T10D and glucose-deprived cell culture medium supplemented with the same concentration of butyrate found in S2T10D supernatant, induced a pH-independent cancer cell growth inhibition accompanied by downregulation of cyclin D1 at mRNA level. The downregulation of cyclin D1 gene expression was accompanied by cell cycle arrest in G2/M phase and decrease of cyclin B1 and D1 protein levels. This in vitro study underlines the impact of Lpb. plantarum in the growth inhibition of cancer cells, and proposes butyrate-mediated cell cycle regulation as a potential involved mechanism. Since the production of butyric acid in Lpb. plantarum has been proven strain-dependent and differentially boosted by specific prebiotic compounds, our results open future research paths to determine whether this metabolic activity could be modulated in vivo by enhancing this antiproliferative effects on cancer cells.

Angelica sinensis polysaccharide improves rheumatoid arthritis by modifying the expression of intestinal Cldn5, Slit3 and Rgs18 through gut microbiota

Rheumatoid arthritis (RA) is an autoimmune disease with a high incidence. Recent studies have demonstrated that diet can contribute to the development and progression of RA. Indeed, non-starch polysaccharides (NSPs) were known to be related to the improvement of RA. In this study, the collagen-induced rats were administrated with Angelica sinensis polysaccharide (ASP) at 200 mg/kg (L), 400 mg/kg (M), or 800 mg/kg (H). Results showed that ASP could reduce joint swelling and significantly inhibit anti-CII-antibodies and pro-inflammatory factors in RA, H group showed the best treatment among them. Further analysis using 16S rDNA sequencing suggested that ASP could shape the gut microbiota composition. Several key bacteria, including norank_f__norank_o__Clostridia_UCG-014, Lactobacillus, norank_f__Oscillospiraceae, and norank_f__Desulfovibrionaceae, were found to be related to the development of RA. The colonic transcriptome showed that ASP could restore RA-induced intestinal dysfunction, such as tight junction disarrangement, by upregulating Cldn5. The balance between osteoblasts and osteoclasts might be modified by regulating the expression of Slit3 and Rgs18 to alleviate RA, which may be correlated with gut microbiota. Our results suggested that ASP improved RA by regulating gut microbiota and gene expression, revealing a positive relationship between dietary patterns and RA.