Chitosan nanomedicines-engineered bifidobacteria complexes for effective colorectal tumor-targeted delivery of SN-38.

The clinical application of 7-ethyl hydroxy-camptothecin (SN-38) maintains challenges not only due to its poor solubility and stability but also the lack of effective carriers to actively deliver SN-38 to deep tumor sites. Although SN-38-based nanomedicines could improve the solubility and stability from different aspects, the tumor targeting efficiency remains very low. Leveraging the hypoxic taxis of bifidobacteria bifidum (B. bifi) to the deep tumor area, we report SN-38-based nanomedicines-engineered bifidobacterial complexes for effective tumor-targeted delivery. Firstly, SN-38 was covalently coupled with poly-L-glutamic acid (L-PGA) and obtained soluble polymeric prodrug L-PGA-SN38 to improve its solubility and stability. To prolong the drug release, L-PGA-SN38 was mildly complexed with chitosan to form nanomedicines, and nanomedicines engineered B. bifi were further elaborated via electrostatic interaction of the excess of cationic chitosan shell from nanomedicines and anionic teichoic acid from B. bifi. The engineered B. bifi complexes inherited the bioactivity of native B. bifi and exhibited distinctly enhanced accumulation at the tumor site. More importantly, significantly elevated anti-tumor efficacy was achieved after the treatment of CS-L-PGA-SN38 NPs/B. bifi complexes, with favorable tumor suppression up to 80%. Such a B. bifi-mediated delivery system offers a promising platform for effective drug delivery and enhanced drug accumulation in the hypoxia deep tumor with superior anti-tumor efficacy.

Antiaging Effects of Human Fecal Transplants with Different Combinations of Bifidobacterium bifidum LTBB21J1 and Lactobacillus casei LTL1361 in d-Galactose-Induced Mice.

The feces of healthy middle-aged and old people were first transplanted into d-galactose-induced aging mice to construct humanized aging mice with gut microbiota (FMTC) to confirm the antiaging effect of probiotics produced from centenarians. The mouse model was then treated with centenarian-derived Bifidobacterium bifidum (FMTL), Lactobacillus casei (FMTB), and their mixtures (FMTM), and young mice were used as the control. Compared with the FMTC group, the results demonstrated that the probiotics and their combinations alleviated neuronal damage, increased antioxidant capacity, decreased inflammation, and enhanced cognitive and memory functions in aging mice. In the gut microbiota, the relative abundance of Lactobacillus, Ligilactobacillus, and Akkermansia increased and that of Desulfovibrio and Colidextribacter decreased in the FMTM group compared with that in the FMTC group. The three probiotic groups displayed significant changes in 15 metabolites compared with the FMTC group, with 4 metabolites showing increased expression and 11 metabolites showing decreased expression. The groups were graded as Control > FMTM > FMTB > FMTL > FMTC using a newly developed comprehensive quantitative scoring system that thoroughly analyzed the various indicators of this study. The beneficial antiaging effects of probiotics derived from centenarians were quantitatively described using a novel perspective in this study; it is confirmed that both probiotics and their combinations exert antiaging effects, with the probiotic complex group exhibiting a larger effect.

Probiotics induce intestinal IgA secretion in weanling mice potentially through promoting intestinal APRIL expression and modulating the gut microbiota composition.

Intestinal infections are strongly associated with infant mortality, and intestinal immunoglobulin A (IgA) is important to protect infants from intestinal infections after weaning. This study aims to screen probiotics that can promote the production of intestinal IgA after weaning and further explore their potential mechanisms of action. In this study, probiotics promoting intestinal IgA production were screened in weanling mouse models. The results showed that oral administration of Bifidobacterium bifidum (B. bifidum) FL228.1 and Bifidobacterium bifidum (B. bifidum) FL276.1 significantly enhanced IgA levels in the small intestine and upregulated the expression of a proliferation-inducing ligand (APRIL) and its upstream regulatory factor toll-like receptor 4 (TLR4). Furthermore, B. bifidum FL228.1 upregulated the relative abundance of Lactobacillus, while B. bifidum FL276.1 increased the relative abundance of Marvinbryantia and decreased Mucispirillum, further elevating intestinal IgA levels. In summary, B. bifidum FL228.1 and B. bifidum FL276.1 can induce IgA production in the intestinal tract of weanling mice by promoting intestinal APRIL expression and mediating changes in the gut microbiota, thus playing a significant role in enhancing local intestinal immunity in infants.

GH136-encoding gene (perB) is involved in gut colonization and persistence by Bifidobacterium bifidum PRL2010.

Bifidobacteria are commensal microorganisms that typically inhabit the mammalian gut, including that of humans. As they may be vertically transmitted, they commonly colonize the human intestine from the very first day following birth and may persist until adulthood and old age, although generally at a reduced relative abundance and prevalence compared to infancy. The ability of bifidobacteria to persist in the human intestinal environment has been attributed to genes involved in adhesion to epithelial cells and the encoding of complex carbohydrate-degrading enzymes. Recently, a putative mucin-degrading glycosyl hydrolase belonging to the GH136 family and encoded by the perB gene has been implicated in gut persistence of certain bifidobacterial strains. In the current study, to better characterize the function of this gene, a comparative genomic analysis was performed, revealing the presence of perB homologues in just eight bifidobacterial species known to colonize the human gut, including Bifidobacterium bifidum and Bifidobacterium longum subsp. longum strains, or in non-human primates. Mucin-mediated growth and adhesion to human intestinal cells, in addition to a rodent model colonization assay, were performed using B. bifidum PRL2010 as a perB prototype and its isogenic perB-insertion mutant. These results demonstrate that perB inactivation reduces the ability of B. bifidum PRL2010 to grow on and adhere to mucin, as well as to persist in the rodent gut niche. These results corroborate the notion that the perB gene is one of the genetic determinants involved in the persistence of B. bifidum PRL2010 in the human gut.

Enhanced Immunogenic Cell Death and Antigen Presentation via Engineered Bifidobacterium bifidum to Boost Chemo-immunotherapy.

The immunogenic cell death (ICD) of tumor cells has aroused great interest in the field of immunotherapy, mainly due to the production of plentiful tumor-associated antigens (TAAs) and damage-associated molecule patterns. However, doxorubicin (DOX)-induced tumor-specific T-cell-mediated immune response is usually very weak because of antigen presentation deficiency and the immunosuppressive tumor microenvironment (ITME). Herein, the probiotic Bifidobacterium bifidum (Bi) was covalently modified with DOX-loaded CaP/SiO2 nanoparticles (DNPs@Bi) for tumor therapy. On one hand, the pH-responsive release of DOX could induce chemotherapy and ICD in the ITME. On the other hand, tumor-targeting Bi is able to significantly enhance the presentation of TAAs from B16F10 cells to DCs via Cx43-dependent gap junctions. Due to the combination of enhanced ICD and TAAs presentation, the maturation of DCs and the infiltration of cytotoxic T lymphocytes in the ITME were stimulated. As a result, in vivo antitumor experiments demonstrated that DNPs@Bi prolonged the survival rate and significantly inhibited the tumor progression and metastasis. This strategy of bacterial-driven hypoxia-targeting delivery systems offers a promising approach to tumor chemo-immunotherapy.

Alleviation of Porphyromonas gingivalis or Its Extracellular Vesicles Provoked Periodontitis and Cognitive Impairment by Lactobacillus pentosus NK357 and Bifidobacterium bifidum NK391.

Porphyromonas gingivalis (PG) is closely involved in the outbreak of periodontitis and cognitive impairment (CI). Herein, we examined the effects of anti-inflammatory Lactobacillus pentosus NK357 and Bifidobacterium bifidum NK391 on PG- or its extracellular vesicles (pEVs)-induced periodontitis and CI in mice. Oral administration of NK357 or NK391 significantly decreased PG-induced tumor necrosis factor (TNF)-α, receptor activator of nuclear factors κB (RANK), and RANK ligand (RANKL) expression, gingipain (GP)+lipopolysaccharide (LPS)+ and NF-κB+CD11c+ populations, and PG 16S rDNA level in the periodontal tissue. Their treatments also suppressed PG-induced CI -like behaviors, TNF-α expression and NF-κB-positive immune cells in the hippocampus and colon, while PG-suppressed hippocampal BDNF and N-methyl-D-aspartate receptor (NMDAR) expression increased. The combination of NK357 and NK391 additively alleviated PG- or pEVs-induced periodontitis, neuroinflammation, CI-like behaviors, colitis, and gut microbiota dysbiosis and increased PG- or pEVs-suppressed BDNF and NMDAR expression in the hippocampus. In conclusion, NK357 and NK391 may alleviate periodontitis and dementia by regulating NF-κB, RANKL/RANK, and BDNF-NMDAR signaling and gut microbiota.

Establishment of a gut-on-a-chip device with controllable oxygen gradients to study the contribution of Bifidobacterium bifidum to inflammatory bowel disease.

Supplemental Bifidobacterium has been shown to aid in the prevention, alleviation, and treatment of inflammatory bowel disease (IBD), but the progression and mechanisms are largely unstudied, partly because of a lack of appropriate models. In vitro human gut models must accurately recreate oxygen concentration gradients consistent with those in vivo to mimic gene expression, metabolism, and host-microbiome interactions. A non-equipment-intensive and inexpensive method for constructing the gut-on-a-chip with physiological oxygen concentration gradients remains challenging. Here, we propose a simple strategy using numerical simulations in a dual-channel gut-on-a-chip to guide chip design and achieve controllable oxygen gradients. By varying the size of microchannels, blocking the oxygen penetration of the polydimethylsiloxane layer at a given location, and controlling the flow of hypoxic/aerobic media, this strategy creates steep gradients across the intestinal epithelium. IBD symptoms were induced on the chip by tumor necrosis factor-α and lipopolysaccharide treatment. Bifidobacterium bifidum has been validated to contribute to the stability of the intestinal epithelial barrier, including preventing epithelial barrier disruption and promoting the repair of damaged intestinal epithelial cell monolayers. These effects may be associated with the co-localization of Bifidobacterium bifidum and ZO-1. This simple but robust approach for designing microfluidic devices is applicable to various organs-on-chips in which fluid dynamics and concentration profiles between different media must be considered. With the customized chip, the integration of activated Bifidobacterium bifidum provides an initial step toward developing a multi-factorial IBD platform. The approach could be scaled up for disease modeling, high-throughput drug screening and personalized medicine.

Bifidobacterium bifidum FJSWX19M5 alleviated 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced chronic colitis by mitigating gut barrier injury and increasing regulatory T cells.

Probiotics have been evaluated as alternative approaches for preventing the relapse of Crohn's disease (CD). Previously, we observed strain-specific anti-inflammatory properties of Bifidobacterium bifidum in 2,4,6-trinitrobenzene sulfonic acid (TNBS) acute colitis models. In this study, we further assessed the effects of several B. bifidum strains on colonic damage, fibrosis, inflammatory factors, intestinal microbial and metabolic profiles, and peripheral regulatory T cells (Tregs) in the context of TNBS chronic colitis in mice. These results indicated that B. bifidum FJSWX19M5, but not FXJWS17M4, ameliorated body weight loss, reduced colonic shortening and injury, decreased markers of gut inflammation, and rebalanced colonic metabolism in TNBS-treated mice. FJSWX19M5 supplementation also promoted Treg cell differentiation and intestinal barrier restoration compared to other strains. All living B. bifidum strains (FJSWX19M5, FXJWS17M4 and FHENJZ3M6) seemed to restore the disruption of the gut microbiota caused by TNBS. The co-culture of B. bifidum strains and mesenteric lymph node cells from TNBS-treated mice showed that those strains with anti-colitis could induce higher IL-10 levels and a lower ratio of IL-22/IL-10 and IL-17/IL-10 when compared to those strains that were not protective. Furthermore, heat-killed FJSWX19M5 exhibited a relief effect on colitis-related symptoms (including body weight loss, colonic shortening and injury). These data imply that specific B. bifidum strains or their lysates may be the current therapeutic alternatives for CD.

Heat-Killed Bifidobacterium bifidum B1628 May Alleviate Dextran Sulfate Sodium-Induced Colitis in Mice, and the Anti-Inflammatory Effect Is Associated with Gut Microbiota Modulation.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease associated with gut dysbiosis. This study aimed to investigate the effects of heat-killed Bifidobacterium bifidum B1628 (HB1628) in dextran sulfate sodium (DSS)-induced colitis in mice. The following three mouse groups were included (n = eight per group): NC (normal control), DSS (colitis), and HB1628 (colitis and postbiotic). The mice in the DSS group showed significant weight loss and histological damage, developed bloody diarrhea, scored high in the disease activity index (DAI), and exhibited increases in pro-inflammatory cytokines (interleukin [IL]-1ß, IL-6, and tumor necrosis factor [TNF]-α) and decreases in an anti-inflammatory cytokine (IL-13) in the serum. These changes were accompanied by gut microbiota modulation in colitis mice (decreases in Rikenellaceae and Eubacterium; increases in Peptostreptococcaceae, Bacteroides vulgatus, and Parasutterella excrementihominis). The HB1628 group had lower DAIs, histology scores, and serum levels of pro-inflammatory cytokines (IL-1ß and TNF-α), but higher levels of an anti-inflammatory cytokine (IL-13), compared with the DSS group, suggesting a less severe inflammatory state after the HB1628 intervention. Additionally, HB1628 improved DSS-induced gut dysbiosis, which is evidenced by increases in intestinal beneficial bacteria, such as Lactobacillus, and decreases in known unfavorable taxa in IBD, e.g., Porphyromonadaceae, Subdoligranulum, Lachnospiraceae bacterium 3_1_46FAA, and Alistipes indistinctus. Functional metagenomics revealed three significantly enriched metabolic pathways in the HB1628 group (namely, the aerobic respiration I [cytochrome c] pathway and the superpathways of L-phenylalanine biosynthesis and L-tryptophan biosynthesis, respectively). In conclusion, our results showed that HB1628 effectively improved the inflammation state and tissue damage in DSS-induced colitis mice, and the symptom relief effect was accompanied by obvious gut microbiota remodulation.

[Bifidobacterium bifidum TMC3115 Promotes Early Life Intestinal Microbiota Building to Alleviate Symptoms of Inflammatory Bowel Disease].

Objective: To investigate the effects of using Bifidobacterium bifidum TMC3115 in early life on intestinal microbiota and immune functions and the long-term impact on inflammatory bowel disease. Methods: Fourteen pregnant BALB/c mice were purchased and 84 newborn BALB/c mice were subsequently obtained. Then, the newborn mice were randomly assigned to a normal saline (NS) group and a TMC3115 group, given via oral gavage normal saline and TMC3115, respectively, at a daily volume of 0.2 mL for each mouse. About 42 mice were assigned to each group. The gavage was stopped after 3 weeks. At this point, half of the mice in each group were sacrificed, and then the remaining mice in each group were randomly divided into NS-water group, NS-DSS group, TMC3115-water group, and TMC3115-DSS group, with about 10 mice in each group. The mice were given regular feed until the end of week 6 when they were given 3% dextran sulphate sodium (DSS) ad libitum for 4 days to establish the enteritis model, while the non-modeling groups were given pure water ad libitum. The experiment ended after 6 weeks and 4 days. The weekly body mass changes of the mice were documented. The intestinal tissue at the end of the experiment and the fecal samples, spleen and serum of the mice at 3 weeks and at the end of the experiment were collected to determine the pathology scores of colonic inflammation, the composition of fecal gut microbiota, spleen organ index and the mass concentration of serum cytokines. Results: 1) At the end of the experiment, the inflammatory pathology score was significantly lower in the TMC3115-DSS group compared with that of the Saline-DSS group ( P<0.05), with less disruption of colonic crypt structures and other structures, less inflammatory infiltration, and more intact epithelial structures. 2) At 3 weeks, in comparison with those of the NS group, the relative abundance of Bifidobacteriumwas significantly higher in the feces of the TMC3115 ( P<0.05), the relative abundance of both Enterococcusand Staphylococcuswas lower ( P<0.05), the splenic organ index was significantly higher ( P<0.05), and interleukin (IL)-10 was significantly decreased ( P<0.05), while there was no significant change in IL-6 or TNF-α ( P>0.05). At the end of the experiment, in comparison with those of the NS-DSS group that undergone DSS induction, the TMC3115-DSS group had reduced relative abundance of Staphylococcus, Staphylococcus tumefaciens and Escherichia/ Shigellain the feces ( P<0.05), while the splenic organ index was significantly higher ( P<0.05), and there were no significant changes in IL-6 or TNF-α ( P>0.05). Conclusion: The use of TMC3115 in early life promotes the construction of gut microbiota in neonatal mice, thereby producing a long-term effect that alleviates colitis in mice, but the mechanisms involved are still not fully understood.

[Protective effect and mechanism of Bifidobacterium bifidum TMC3115 on long-term colitis in mice which exposed to antibiotic in early life].

OBJECTIVE: To explore the protective effect and mechanism of Bifidobacterium bifidum TMC3115 of improving the gut microbiota disorder caused by antibiotic exposurein early life, and the possible protection of inflammatory bowel disease in adulthood in mice. METHODS: 80 newborn mice were randomly divided into 3 groups, a blank control group(n=40), a ceftriaxone exposure group(n=20), a Bifidobacterium bifidum TMC3115 intervention group(n=20). After birth, they were respectively treated with saline, ceftriaxone(100 mg/kg), and ceftriaxone(100 mg/kg) + TMC3115(1×10~9CFU/d) for 3 weeks. After 3 weeks, half of each group was randomly sacrificed, and the rest were normally fed to 6 weeks. At 6 weeks, the blank control group was randomly divided into a negative control group(n=10) and a colitis model group(n=10). The negative control group drunk pure water freely, and the other three groups were added 3% DSS to the drinking water for 4 days to induce colitis. At 6 weeks and 4 days, the remaining mice were sacrificed. The weight change, spleen coefficient, gut microbiota analysis based on second-generation sequencing and serum tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), and interleukin-10(IL-10)levels of the mice at 3 weeks and after DSS intervention were recorded. In addition, the colon length and inflammation pathology score of the mice after DSS intervention were also measured. RESULTS: At 3 weeks, compared with the control, antibiotic exposure in the early life inhibited the weight gain and reduced the diversity and uniformity of the gut microbiota of the mice(P<0.05). The intervention of TMC3115 under antibiotic exposure during this period increased the relative abundance of Bifidobacterium in the intestines(P<0.05), and the effect still existed after DSS stimulation in adulthood, laying the foundation for TMC3115 to exert long-term benefits. After DSS stimulation in adulthood, mice showed significant weight gain inhibition, colon length shorteningand inflammation pathology scoreincrease compared with the negative control(P<0.05), showed the inflammatory bowel disease(IBD)model was successfully constructed. The relative abundance of beneficial bacteria such as Lactobacillus in the Bifidobacterium bifidum TMC3115 intervention group increased compared with the ceftriaxone exposure group(P<0.05), while the relative abundance of harmful bacteria such as Staphylococcus, Clostridium, and Desulfovibrio decreased(P<0.05). Furthermore, the mice exposed to antibiotic in early life produced a stronger immune response, but the mice which received TMC3115 intervention at the same time had a significant decrease in serum TNF-α and IL-6 levels and increase in IL-10 level compared with the mice which only interfered with antibiotics(P<0.05). CONCLUSION: Antibiotic exposure in early life is a negative factor for long-term inflammatory bowel disease, and TMC3115 has preventive significance for long-term inflammatory bowel disease under the background of antibiotic exposure. The mechanism of TMC3115 may be to adjust the gut microbiota and balance the immune system.

Anti-Tumor Effect of Heat-Killed Bifidobacterium bifidum on Human Gastric Cancer through Akt-p53-Dependent Mitochondrial Apoptosis in Xenograft Models.

Paraprobiotics, inactivated microbial cells, regulate immune system and exhibit antioxidant and anti-inflammatory activities in patients with weakened immunity or the elderly. This study evaluated the anti-tumor effects of heat-killed Bifidobacterium and Lactobacillus on human gastric cancer MKN1 cells in vitro and in vivo in xenograft animal models. First, cytotoxicity and apoptosis in MKN1 cells of 11 different heat-killed Bifidobacterium or Lactobacillus strains were examined using the MTT assay or flow cytometry, respectively. Then, BALB/c nude mice xenograft animal models were implanted with human gastric cancer MKN1 cells and orally administered a selected single or a mixture of heat-killed bacterial strains to investigate their inhibitory effect on tumor growth. In addition, the expression of p-Akt, p53, Bax, Bak, cleaved caspase-9, -3, and PARP in the tumor tissues was analyzed using Western blotting assay or immunohistochemistry staining. The results show that heat-killed B. bifidum MG731 (MG731), L. reuteri MG5346 (MG5346), and L. rhamnosus MG5200 (MG5200) induced relatively greater apoptosis than other strains in MKN1 cells. Oral administration of a single dose or a mixture of MG731, MG5346, or MG5200 significantly delayed tumor growth, and MG731 had the most effective anti-tumor effect in the xenograft model. Protein expression of p-Akt, p53, Bax, cleaved caspase-3 and -9, and PARP in tumors derived from the xenograft model correlated with the results of the immunohistochemistry staining.

Bifidobacterium bifidum and Bacteroides fragilis Induced Differential Immune Regulation of Enteric Glial Cells Subjected to Exogenous Inflammatory Stimulation.

Enteric glial cells (EGCs) are involved in intestinal inflammation. In this study, we will investigate how Bifidobacterium bifidum (B.b.) and Bacteroides fragilis (B.f.) influence EGC regulation. After pretreatment with lipopolysaccharide (LPS) and interferon-γ (IFN-γ), the expressions of major histocompatibility complex class II (MHC-II), CD80, CD86, glial cell line-derived neurotrophic factor (GDNF), toll-like receptor 2 (TLR-2), and tumor necrosis factor-α (TNF-α) in EGCs were detected using polymerase chain reaction and western blot after co-culture with the supernatants of B.b. or B.f. (multiplicity of infection, 40:1 or 80:1). Finally, EGCs were co-cultured with naive CD4+ T cells, and the expressions of interleukin (IL)-2, IL-4, IL-10, and IL-17 in supernatant were measured using enzyme-linked immunosorbent assay (ELISA). The mRNA expressions of MHC-II and CD86 in EGCs were increased after combined stimulation with LPS and IFN-γ. The expressions of MHC-II, GDNF, TLR-2, and TNF-α were all significantly upregulated in stimulated EGCs. The B.b. supernatant downregulated the expressions of MHC-II, GDNF, TLR-2, and TNF-α in stimulated EGCs, whereas the B.f. supernatant upregulated TLR-2 expression and downregulated MHC-II expression. The expressions of IL-4, IL-2, and IL-17 after co-culture of naive CD4+ T cells and stimulated EGCs were significantly increased. The supernatant of B.b. or B.f. downregulated the expressions of these cytokines. The low-concentration B.b. supernatant upregulated IL-10 expression. Conclusions B.b. and B.f. may influence intestinal inflammation by regulating MHC-II, GDNF, TLR-2, and TNF-α expression in EGCs and IL-4, IL-2, IL-17, and IL-10 secretion.

A recombinant Bifidobacterium bifidum BGN4 strain expressing the streptococcal superoxide dismutase gene ameliorates inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is a gastrointestinal disease characterized by diarrhea, rectal bleeding, abdominal pain, and weight loss. Recombinant probiotics producing specific proteins with IBD therapeutic potential are currently considered novel drug substitutes. In this study, a Bifidobacterium bifidum BGN4-SK strain was designed to produce the antioxidant enzymes streptococcal superoxide dismutase (SOD) and lactobacillus catalase (CAT), and a B. bifidum BGN4-pBESIL10 strain was proposed to generate an anti-inflammatory cytokine, human interleukin (IL)-10. In vitro and in vivo efficacy of these genetically modified Bifidobacterium strains were evaluated for colitis amelioration. RESULTS: In a lipopolysaccharide (LPS)-stimulated HT-29 cell model, tumor necrosis factor (TNF)-α and IL-8 production was significantly suppressed in the B. bifidum BGN4-SK treatment, followed by B. bifidum BGN4-pBESIL10 treatment, when compared to the LPS-treated control. Synergistic effects on TNF-α suppression were also observed. In a dextran sodium sulphate (DSS)-induced colitis mouse model, B. bifidum BGN4-SK treatment significantly enhanced levels of antioxidant enzymes SOD, glutathione peroxidase (GSH-Px) and CAT, compared to the DSS-only group. B. bifidum BGN4-SK significantly ameliorated the symptoms of DSS-induced colitis, increased the expression of tight junction genes (claudin and ZO-1), and decreased pro-inflammatory cytokines IL-6, IL-1ß and TNF-α. CONCLUSIONS: These findings suggest that B. bifidum BGN4-SK ameliorated DSS-induced colitis by generating antioxidant enzymes, maintaining the epithelial barrier, and decreasing the production of pro-inflammatory cytokines. Although B. bifidum BGN4-pBESIL10 exerted anti-inflammatory effects in vitro, the enhancement of IL-10 production and alleviation of colitis were very limited.

Nanodrug-loaded Bifidobacterium bifidum conjugated with anti-death receptor antibody for tumor-targeted photodynamic and sonodynamic synergistic therapy.

Using bacteria for tumor-targeted therapy has attracted much attention in recent years. However, how to improve the targeted delivery and cancer therapy efficacy is an important but challenging scientific issue. Herein, a drug delivery system using a probiotic as a carrier was developed for tumor-targeted photodynamic and sonodynamic synergistic therapy. In this system, chlorin e6 (Ce6) nanoparticles (NPs) were prepared and incorporated into B. bifidum, followed by the conjugation of anti-death receptor 5 antibody (anti-DR5 Ab). Interestingly, B. bifidum under 671 nm laser or ultrasound (US) irradiation could generate reactive oxygen species (ROS), and Ce6-B. bifidum-anti-DR5 Ab obtained could target hypoxic regions in tumor with high efficiency after intravenous injection. The ROS level generated by Ce6-B. bifidum-anti-DR5 Ab under both laser and US irradiation was much higher than the combined ROS generated separately using a laser and US for the same probiotics. The cytotoxicity and laryngeal tumor growth-inhibiting efficiency of Ce6-B. bifidum-anti-DR5 Ab under both laser and US irradiation were significant higher than the values obtained using laser or US irradiation alone, which demonstrated the synergistic effect on tumor growth. B. bifidum could be eliminated from the body without exerting harmful effects on mouse health. This strategy is a platform that can be extended to treat other solid tumors. STATEMENT OF SIGNIFICANCE: Using bacteria as drug delivery carriers will show unique advantages. However, how to improve the targeted delivery efficiency and tumor inhibiting capacity is a challenging scientific issue. Herein, a delivery system using a probiotic as carrier was developed for tumor-targeted therapy. In this delivery system, chlorin e6 nanoparticles were prepared and then incorporated into living Bifidobacterium bifidum (B.bifidum), followed by the conjugation of anti-death receptor 5 antibody. This delivery system could efficiently target to mouse tumors, accumulate the hypoxic areas and inhibit the tumor growth through the photodynamic and sonodynamic synergistic effect. Our results will provide a platform for B.bifidum-mediated tumor targeted therapy.

Microbial and metabolic profiles of bronchopulmonary dysplasia and therapeutic effects of potential probiotics Limosilactobacillus reuteri and Bifidobacterium bifidum.

AIMS: Bronchopulmonary dysplasia (BPD) is a common respiratory disease in newborns; however, there is no effective treatment. We aimed to investigate the effects of the potential probiotics Limosilactobacillus reuteri and Bifidobacterium bifidum on BPD using 16S rDNA sequencing and metabolomics methods. METHODS AND RESULTS: Faecal samples were collected from 10 BPD patients and 10 healthy subjects. 16S rDNA sequencing results showed that microbial diversity was decreased and compositions were affected in BPD. Escherichia-Shigella and Clostridium_sensu_stricto_1 were increased in the BPD group, and Enterobacteriaceae, Megamonas, Blautia, Lactobacillus (Limosilactobacillus), [Eubacterium]_coprostanoligenes_group, Phascolarctobacterium and Bifidobacterium were reduced. Metabolomics analysis identified 129 differentiated metabolites that were changed in BPD patients, and they were associated with a preference for carbohydrate metabolism in translation and metabolism during genetic information processing. Correlation analysis revealed a remarkable relationship between gut microbiota and metabolites. Subsequently, a BPD cell model was constructed to test the effect of the potential probiotics. Cell function experiments verified that treatment with the potential probiotics L. reuteri and B. bifidum promoted proliferation and inhibited apoptosis of hyperoxia-induced MLE-12 cells. In addition, treatment with the potential probiotics L. reuteri and B. bifidum reduced inflammation and oxidative stress damage. CONCLUSIONS: Treatment with the potential probiotics L. reuteri and B. bifidum could alleviate BPD and reduce inflammation and oxidative stress damage. SIGNIFICANCE AND IMPACT: This study was the first to report positive roles for the potential probiotics L. reuteri and B. bifidum in BPD. The potential probiotics L. reuteri and B. bifidum were shown to reduce inflammation and oxidative stress damage in BPD. This study provided new insights on the pathogenesis and treatment of BPD.

Bifidobacterium bifidum relieved DSS-induced colitis in mice potentially by activating the aryl hydrocarbon receptor.

Inflammatory bowel disease (IBD) characterized by relapsed intestinal inflammation and barrier function disruption is still a great therapeutic challenge. This study aimed to screen probiotics that have the potential to help alleviate IBD and further elucidate their mechanism of action. Caco-2 cell differentiated monolayers and RAW264.7 cells stimulated by lipopolysaccharide (LPS) were used for probiotic screening in vitro, and then the efficacies of the obtained six bacterial strains were evaluated in mice with dextran sulfate sodium (DSS)-induced colitis. The results showed that all of the strains at varying degrees could increase the transepithelial electrical resistance (TEER) value, decrease the influx of FITC-dextran in Caco-2 cell monolayers and attenuate the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in LPS-stimulated RAW264.7 cells. In vivo experiments indicated that Bifidobacterium bifidum FL-276.1 (FL-276.1) and Bifidobacterium bifidum FL-228.1 (FL-228.1) showed the best efficacies to ameliorate body weight loss, colon shortening, and intestinal barrier disruption. Accordingly, in FL-276.1 and FL-228.1 groups, the genes of zonula occludens-1 (ZO-1), claudin-4, occludin and mucin 2 (Muc2) in mouse colonic tissues were significantly upregulated, while TNF-α, IL-1ß and IL-6 were downregulated. Further results showed that strains FL-276.1 and FL-228.1 could activate the aryl hydrocarbon receptor (AhR) in the intestine. Our study showed that the two Bifidobacterium bifidum strains, FL-276.1 and FL-228.1, ameliorated DSS-induced colitis by enhancing the intestinal barrier and anti-inflammation potentially via the AhR pathway.

Effect of Probiotic Bifidobacterium bifidum TMC3115 Supplementation on Psychosocial Stress Using a Sub-Chronic and Mild Social Defeat Stress in Mice.

With the accumulation of knowledge on the relation between psychological stress and gut microbiota, there is growing interest in controlling stress and/or mood disorders via probiotic supplementation. We aimed to examine the effect of probiotic Bifidobacterium bifidum TMC3115 (TMC3115) supplementation using a sub-chronic and mild social defeat stress murine model in this study. TM3115 supplementation maintained body weight gain and alleviated a polydipsia-like symptom induced by the stress. In the analyses of fecal and cecal bacterial profiles, expansions of Proteobacteria in stressed mice and increases in Actinobacteria and Bifidobacterium in mice supplemented with TMC3115 were observed. There was no marked difference in the diversity of cecal bacteria between the tested mice. Elevated serum levels of inflammatory markers such as tumor necrosis factor (TNF)-α and interleukin (IL)-6 were observed in the stressed mice, while TMC3115 only reduced the IL-6 level. These findings suggest that TMC3115 supplementation confers tolerance to psychosocial stress in the host through modulation of the gut microbiota and alleviation of stress-induced inflammatory responses. Furthermore, it may be expected to exert prevention and treatment of disorders related to peripheral IL-6, including depression.

Nanoengineered Bifidobacterium bifidum with Optical Activity for Photothermal Cancer Immunotheranostics.

There is substantial interest regarding the understanding and designing of nanoengineered bacteria to combat various fatal diseases. Here, we report the nanoengineering of Bifidobacterium bifidum using Cremophor EL to encapsulate organic dye molecules by simple incubation and washing processes while maintaining the bacterial morphology and viability. The prepared functional bacteria exhibit characteristics such as optical absorbance, unique fluorescence, powerful photothermal conversion, low toxicity, excellent tumor targeting, and anticancer efficacy. They also displayed significant in vivo fluorescent expression in implanted colorectal cancerous tumors. Moreover, the powerful photothermal conversion of the functional bacteria could be spatiotemporally evoked by biologically penetrable near-infrared laser for effective tumor regression in mice, with the help of immunological responses. Our study demonstrates that a nanoengineering approach can provide the strong physicochemical traits and attenuation of living bacterial cells for cancer immunotheranostics.

Commensal segmented filamentous bacteria-derived retinoic acid primes host defense to intestinal infection.

Interactions between the microbiota and mammalian host are essential for defense against infection, but the microbial-derived cues that mediate this relationship remain unclear. Here, we find that intestinal epithelial cell (IEC)-associated commensal bacteria, segmented filamentous bacteria (SFB), promote early protection against the pathogen Citrobacter rodentium, independent of CD4+ T cells. SFB induced histone modifications in IECs at sites enriched for retinoic acid receptor motifs, suggesting that SFB may enhance defense through retinoic acid (RA). Consistent with this, inhibiting RA signaling suppressed SFB-induced protection. Intestinal RA levels were elevated in SFB mice, despite the inhibition of mammalian RA production, indicating that SFB directly modulate RA. Interestingly, RA was produced by intestinal bacteria, and the loss of bacterial-intrinsic aldehyde dehydrogenase activity decreased the RA levels and increased infection. These data reveal RA as an unexpected microbiota-derived metabolite that primes innate defense and suggests that pre- and probiotic approaches to elevate RA could prevent or combat infections.