Oral delivery of Bifidobacterium longum expressing α-melanocyte-stimulating hormone to combat ulcerative colitis.

α-Melanocyte-stimulating hormone (α-MSH) is a tridecapeptide derived from pro-opiomelanocortin that exhibits potent anti-inflammatory properties by regulating the production of inflammatory mediators. This peptide has been well established in several inflammatory models, including inflammatory bowel disease (IBD). However, its extremely short duration in vivo limits its clinical application. To address this limitation, Bifidobacterium was used here as a carrier to deliver α-MSH. We utilized α-MSH-engineered Bifidobacterium against IBD, which is closely linked to immune and intestinal microbiota dysfunction. First, we constructed a Bifidobacterium longum secreting α-MSH (B. longum-α-MSH). We then tested the recombinant α-MSH expression and determined its bioactivity in HT-29 cells. To assess its effectiveness, B. longum-α-MSH was used against an ulcerative colitis (UC) model in rats induced by dextran sulfate sodium. The data showed that α-MSH expression in B. longum-α-MSH was effective, and its biological activity was similar to the synthesized one. This UC model experiment indicated that B. longum-α-MSH successfully colonized the intestinal gut, expressed bioactive α-MSH and had a significant anti-inflammatory effect. The results demonstrate the feasibility of preventing IBD by using B. longum-α-MSH.

Oral Bifidobacterium longum expressing alpha-melanocyte-stimulating hormone to fight experimental colitis.

The oral delivery of peptides is a highly attractive treatment approach. However, the harsh environment of the gastrointestinal tract limits its application. Here, we utilize Bifidobacterium as a delivery system to orally deliver a potent anti-inflammatory but short duration peptide alpha-melanocyte-stimulating hormone (α-MSH) against experimental colitis. The aim of our study was to facilitate the efficient oral delivery of α-MSH. We designed a vector of pBDMSH and used it to construct a Bifidobacterium longum expressing α-MSH. We then determined the bioactivity of recombinant Bifidobacterium in lipopolysaccharide-induced inflammatory models of HT-29 cells. Finally, we used Bifidobacterium expressing α-MSH against dextran sulfate sodium (DSS)-induced ulcerative colitis mice. Results based on the myeloperoxidase activity, the levels of inflammatory cytokines TNF-α, IL-1ß, IL-6, and IL-10 and the histological injury of colon tissue reveal recombinant Bifidobacterium was efficient in attenuating DSS-induced ulcerative colitis, suggesting an alternative way to use Bifidobacterium as a delivery system to deliver α-MSH for DSS-induced ulcerative colitis therapy.

Transforming Growth Factor Beta-Induced Is Essential for Endotoxin Tolerance Induced by a Low Dose of Lipopolysaccharide in Human Peripheral Blood Mononuclear Cells.

Our prior study found that transforming growth factor beta-induced (TGFBI) is an important negative regulator in TLR-induced inflammation. However, whether TGFBI may affect inflammation during lipopolysaccharide (LPS)-induced endotoxin tolerance (ET) is still unclear. This study aimed to investigate whether TGFBI was involved in the mechanisms of ET in human through dampening nuclear factor-kappa B (NF-κB) mediated pathway. ET models of isolated healthy volunteers peripheral blood mononuclear cells (PBMCs) were established by pretreating with a low dose of LPS to observe the changes of TGFBI expression during ET induction, compared with ten healthy controls. Moreover, a vector-based short hairpin RNA expression system was used to specifically inhibit TGFBI expression to further explore its role in ET induction. The expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The responses to LPS were determined by the activation of NF-κB, the production of tumor necrosis factor-α (TNF-α) and Nitric Oxide (NO), which were analysed by enzyme-linked immuno sorbent assay (ELISA). The results showed that TGFBI expression in the ET group obviously increased; ET also led to a hyporesponse of PBMCs to LPS with less activation of NF-κB, less production of TNF-α and NO, as well as more expression of TGFBI than those of non-ET group. Moreover, the inhibitory effect was partly refracted in plasmid TGFBI short hairpin RNA (pTGFBI-shRNA) transfected PBMCs. Meanwhile, the absence of TGFBI caused abnormal enhancement of inflammatory cytokine production and it was involved in ET induction through dampening NF-κB mediated pathway. Therefore, TGFBI may be a new target for the clinical treatment of inflammatory disorders.

A engineered Bifidobacterium longum secreting a bioative penetratin-Glucagon-like peptide 1 fusion protein enhances Glucagon-like peptide 1 absorption in the intestine.

Glucagon-like peptide-1 (GLP-1) is an incretin-derived hormone secreted by intestinal L-cells in response to nutrient ingestion. It improves pancreatic function and it is considered to have a potential role in treatment of type 2 diabetes. However, its short half-life limits its therapeutic applications. Here, to circumvent this problem, we engineered Bifidobacterium longum, a bacterium naturally occurring in the intestinal flora, to express a secreted and biologically active form of the human GLP-1. Our data showed that the bacteria secreted our penetratin-GLP-1fusion protein successfully. The penetratin-GLP-1 fusion protein was a fully functional GLP-1 and displayed enhanced absorption significantly (P<0.001) in the colon. This work is the first report of an expressed penetratin-GLP-1 fusion protein in bifidobacteria and lays the foundation for the use of GLP-1-based treatment of type 2 diabetes in the future.

HIV-1 Coreceptor CXCR4 Antagonists Promote Clonal Expansion of Viral Epitope-Specific CD8+ T Cells During Acute SIV Infection in Rhesus Monkeys In Vivo.

BACKGROUND: The underlying molecular mechanisms and the kinetics of T cell receptor (TCR) repertoire selection during administration of CXCR4 or CCR5 inhibitors in infection of AIDS viruses in vivo have remained largely unexplored. Viral epitope-specific CD8(+) T lymphocytes play a dominant role in the control of HIV and simian immunodeficiency virus (SIV). We hypothesized that blockade of CXCR4 or CCR5 might influence the clonal expansion of epitope-specific CD8(+) T cells, contributing to antiviral immune responses in vivo. METHODS: We measured frequencies of the dominant epitope p11C-specific CD8(+) T cells and analyzed the TCR repertoire of those cells in SIV-infected rhesus monkeys treated by CXCR4 or CCR5 inhibitors and vMIP-II, which binds multiple chemokine receptors. RESULTS: A significantly increase in the levels of epitope-specific CD8(+) T cells was observed after blockade of CXCR4 or CCR5 compared with untreated control groups. Those CD8(+) T cells exhibited selected usage of TCR Vß families and complementarity-determining region 3 (CDR3) segments. The clonal expansion of distinct Vß populations could efficiently inhibit SIV replication in vitro, and CXCR4 inhibitor induced more expansion of epitope-specific CD8(+) T cells than CCR5 antagonist (P < 0.01), whereas vMIP-II treatment showed the most marked augmentation of p11C-specific CD8(+) T cells. CONCLUSIONS: Antagonists of HIV coreceptors, particularly CXCR4, play an important role in the clonal expansion of SIV epitope-specific CD8(+) T cells in vivo, thus inhibitors of chemokine receptors such as CXCR4 or CCR5 may contribute to the ability of epitope-specific CD8(+) T cells to inhibit SIV or HIV infection.

Isolation and gut microbiota modulation of antibiotic-resistant probiotics from human feces.

Antibiotic-resistant probiotics may be advantageous for antibiotic-induced gut microbiota imbalance. In this article, we aimed to isolate antibiotic-resistant bacteria as potential probiotics. Feces from 3 healthy adults and 2 infants were used to isolate the antibiotic-resistant bacteria. Then we established gut microbiota imbalance mice model by antibiotics treatment and used it to assess the effect of the probiotics. Finally, we identified 8 isolates, and 6 of them were used as probiotics cocktail. Number of anaerobe, lactobacilli, and Bifidobacterium in feces were higher in the probiotic group (9.47±0.35 log10CFU/g, 8.74±0.18 log10CFU/g, 7.24±0.38 log10CFU/g, respectively) compared with model group (P<0.05). Richness and diversity index of probiotic group (19.79±0.29 and 2.95±0.06, respectively) were larger than model group (P<0.05). Diarrhea and mucosal edema had been alleviated during probiotic treatment. Our results validated that bacteriotherapy was available to treat gut microbiota imbalance.