The experimental radiation therapy involving thermal neutron capture by boron (boron neutron capture therapy, BNCT) offers the advantage of high-LET ions with ranges on the order of a cell nucleus. ...Efforts to implement it have encountered serious difficulties. A practical model system would be able to address the underlying mechanisms of DNA damage and also calibrate Monte Carlo simulations. We describe the characterization of a plasmid-based model in which DNA condensed with a tetra-arginine peptide is co-aggregated with mercapto-closo-dodecaborate (BSH) coated gold nanoparticles (AuNPs). Condensed DNA is an excellent model for cellular chromatin, and the AuNPs are able to function as boron carriers and neutron dosimeters. Data from light scattering, UV–visible spectroscopy, fluorescence spectroscopy, sedimentation behavior, gel electrophoresis, and atomic force microscopy all indicate that the basic peptide acts to co-aggregate the two polyanionic species DNA and BSH-coated AuNPs. This aggregation is easily reversed by an increase in ionic strength to free the plasmid for subsequent assay. We argue that this three-component system is simpler, more convenient, and more flexible than other models requiring covalent attachments between DNA, boron, and/or gold.
•Model system for DNA damage by neutron capture on boron.•Condensed DNA aggregates reproduce the packing in chromatin and the size of cell nuclei.•Gold nanoparticles provide increased boron content over previous models.•Gold nanoparticles are suitable for neutron dosimetry.•DNA easily recoverable due to reversible electrostatic binding.
Bile acids are synthesized from cholesterol in the liver and released into the intestine to aid the digestion of dietary lipids. The host enzymes that contribute to bile acid synthesis in the liver ...and the regulatory pathways that influence the composition of the total bile acid pool in the host have been well established. In addition, the gut microbiota provides unique contributions to the diversity of bile acids in the bile acid pool. Gut microbial enzymes contribute significantly to bile acid metabolism through deconjugation and dehydroxylation reactions to generate unconjugated bile acids and secondary bile acids. These microbial enzymes (which include bile salt hydrolase (BSH) and bile acid-inducible (BAI) enzymes) are essential for bile acid homeostasis in the host and represent a vital contribution of the gut microbiome to host health. Perturbation of the gut microbiota in disease states may therefore significantly influence bile acid signatures in the host, especially in the context of gastrointestinal or systemic disease. Given that bile acids are ligands for host cell receptors (including the FXR, TGR5 and Vitamin D Receptor) alterations to microbial enzymes and associated changes to bile acid signatures have significant consequences for the host. In this review we examine the contribution of microbial enzymes to the process of bile acid metabolism in the host and discuss the implications for microbe-host signalling in the context of C. difficile infection, inflammatory bowel disease and other disease states.
Bile salt hydrolase plays an important role in bile acid-mediated signaling pathways, which regulate lipid absorption, glucose metabolism, and energy homeostasis. Several reports suggest that changes ...in the composition of bile acids are found in many diseases caused by dysbacteriosis.
Here, we present the taxonomic identification of bile salt hydrolase (BSH) in human microbiota and elucidate the abundance and activity differences of various bacterial BSH among 11 different populations from six continents. For the first time, we revealed that bile salt hydrolase protein sequences (BSHs) are distributed in 591 intestinal bacterial strains within 117 genera in human microbiota, and 27.52% of these bacterial strains containing BSH paralogs. Significant variations are observed in BSH distribution patterns among different populations. Based on phylogenetic analysis, we reclassified these BSHs into eight phylotypes and investigated the abundance patterns of these phylotypes among different populations. From the inspection of enzyme activity among different BSH phylotypes, BSH-T3 showed the highest enzyme activity and is only found in Lactobaclillus. The phylotypes of BSH-T5 and BSH-T6 mainly from Bacteroides with high percentage of paralogs exhibit different enzyme activity and deconjugation activity. Furthermore, we found that there were significant differences between healthy individuals and patients with atherosclerosis and diabetes in some phylotypes of BSHs though the correlations were pleiotropic.
This study revealed the taxonomic and abundance profiling of BSH in human gut microbiome and provided a phylogenetic-based system to assess BSHs activity by classifying the target sequence into specific phylotype. Furthermore, the present work disclosed the variation patterns of BSHs among different populations of geographical regions and health/disease cohorts, which is essential to understand the role of BSH in the development and progression of related diseases.
Berberine (BBR) is an effective cholesterol-lowering drug. Although gut microbiota has been implicated in the pharmacological activities of BBR, little evidence exists on the specific species of gut ...microbiota involved in its therapeutic effects, nor on linking gut bacteria to its recognized hypercholesterolemia-alleviating mechanism–upregulation of the low-density lipoprotein receptor (LDLR) in the liver. The present study was performed to identify the specific species of gut microbiota involved in the anti-hyperlipdemic effect of BBR, and interpret its mechanism through linking the gut microbiota and LDLR. The BBR-enriched gut bacterial species were identified by whole genome shotgun sequencing. Pure cultured B. producta was orally administered to C57BL/6 mice to evaluate its anti-hyperlipdemic effect. The LDLR-upregulating effect of B. producta was evaluated both in vitro and in vivo. Orally administration of BBR (200 mg/kg) decreased serum and liver lipid levels in HFD-induced hyperlipidemic mice. Microbiome analysis indicated that Blautia was closely associated with BBR’s lipid-modulating activities. Further analysis revealed that BBR selectively promoted the growth of Blautia producta. Orally treatment of HFD mice with live B. producta reduced obesity and alleviated hyperlipidemia. Notably, the B. producta significantly increased LDLR expression in the liver, and its spent culture supernatant upregulated the LDLR level and promoted LDL uptake by HepG2 cells. Simultaneously, B. producta also linked butyrate-producing and bile salt hydrolase (BSH)-inhibiting effect of BBR. The gut microbiota, especially B. producta, may confers the hypercholesterolemia-alleviating effects of berberine. B. producta represents a novel probiotic that may be used for the treatment of dyslipidemia.
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The study was aimed at evaluating probiotic potential of different Lactobacillus strains isolated from different sources. Lactic acid bacterial strains isolated from fruits, fermented foods and human ...origin survive at low pH (3) and in the presence of bile salt (4%), NaCl (6%) and phenol (0.6%). The strains were able to survive and grow in oro-gastrointestinal tract i.e. lysozyme, pepsin, pancreatin. Most of the isolates adhered to intestinal mucin and produced biofilm when grown in MRS broth with 0.25% porcine mucin. LAB isolates exhibited inhibition against food spoilage organisms and various intestinal pathogens. These isolates possessed the ability to produce gamma amino butyric acid (GABA), bile salt hydrolase (BSH), and β-galactosidase. The LAB strains do not degrade mucin, do not produce DNAse, and are non-haemolytic. Thus, physiological properties and safety evaluation of the strains emphasized further use of these strains in the preparation of diverse probiotic food formulations.
•Lactobacillus pentosus, L. fermentum are potential probiotics from fermented chillies and peru fruit.•Antimicrobial activity against food spoilage microorganisms and fungi.•L. pentosus produce bile salt hydrolase, β-galactosidase and γ-amino butyric acid.•Lactobacillus strains use safely in food fermentations because they do not harbour any virulent factors.
Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against ...radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and
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B atoms, i.e. p+
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B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained at the 62-MeV ocular melanoma-dedicated proton beamline of the INFN-Laboratori Nazionali del Sud (LNS), Catania, Italy. For the first time, we also tested PBCT at the 250-MeV proton beamline used for deep-seated cancers at the Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, Italy. We used Sodium Mercaptododecaborate (BSH) as
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B carrier, DU145 prostate cancer cells to assess cell killing and non-cancer epithelial breast MCF-10A cells for quantifying chromosome aberrations (CAs) by FISH painting and DNA repair pathway protein expression by western blotting. Cells were exposed at various depths along the two clinical SOBPs. Compared to exposure in the absence of boron, proton irradiation in the presence of BSH significantly reduced DU145 clonogenic survival and increased both frequency and complexity of CAs in MCF-10A cells at the mid- and distal SOBP positions, but not at the beam entrance. BSH-mediated enhancement of DNA damage response was also found at mid-SOBP. These results corroborate PBCT as a strategy to render protontherapy amenable towards radiotherapy-resilient tumor. If coupled with emerging proton FLASH radiotherapy modalities, PBCT could thus widen the protontherapy therapeutic index.
Eight acid and bile tolerant Lactobacillus plantarum strains isolated from fruits and fermented foods were identified and characterized in vitro for probiotic attributes. The strains tolerated ...enzymes of simulated oro-gastro-intestinal fluids, pH extremes, bile and retained more than 50% viability during the simulated oro-gastro-intestinal transit. Isolates were able to adhere mucin and autoaggregate strain specifically. Most of the L. plantarum strains exhibited antimicrobial activity against indicator strains and produced health-promoting enzymes β-galactosidase and bile salt hydrolase (BSH). Strains OR, GP and HB produced γ-amino butyric acid (GABA) involved in various metabolic reactions. Safety evaluation assured the safe use of strains in food fermentations. The functional characterization of these strains isolated from fruits and fermented foods accentuated their potential as starter cultures in the manufacturing of functional probiotic products.
•Probiotic Lactobacillus plantarum strains are novel probiotics.•Antimicrobial activity against food spoilage organisms, enteropathogens, and fungi.•L. plantarum strains produce bile salt hydrolase, β-galactosidase, γ-amino butyric acid.•L. plantarum strains do not harbor any virulent factor and safe for use in food fermentations.
Lactobacillus mucosae DPC 6426 has previously demonstrated potentially cardio-protective properties, in the form of dyslipidaemia and hypercholesterolemia correction in an apolipoprotein-E deficient ...mouse model. This study aims to characterise the manner in which this microbe may modulate host bile pool composition and immune response, in the context of cardiovascular disease. Lactobacillus mucosae DPC 6426 was assessed for bile salt hydrolase activity and specificity. The microbe was compared against several other enteric strains of the same species, as well as a confirmed bile salt hydrolase-active strain, Lactobacillus reuteri APC 2587.
Quantitative bile salt hydrolase assays revealed that enzymatic extracts from Lactobacillus reuteri APC 2587 and Lactobacillus mucosae DPC 6426 demonstrate the greatest activity in vitro. Bile acid profiling of porcine and murine bile following incubation with Lactobacillus mucosae DPC 6426 confirmed a preference for hydrolysis of glyco-conjugated bile acids. In addition, the purified exopolysaccharide and secretome of Lactobacillus mucosae DPC 6426 were investigated for immunomodulatory capabilities using RAW264.7 macrophages. Gene expression data revealed that both fractions stimulated increases in interleukin-6 and interleukin-10 gene transcription in the murine macrophages, while the entire secretome was necessary to increase CD206 transcription. Moreover, the exopolysaccharide elicited a dose-dependent increase in nitric oxide and interleukin-10 production from RAW264.7 macrophages, concurrent with increased tumour necrosis factor-α secretion at all doses.
This study indicates that Lactobacillus mucosae DPC 6426 modulates both bile pool composition and immune system tone in a manner which may contribute significantly to the previously identified cardio-protective phenotype.
Boron neutron capture therapy (BNCT) is a promising radiotherapy for treating glioblastoma multiforme (GBM). However, the penetration of drugs (e.g., sodium borocaptate and BSH) for BNCT into brain ...tumors is limited by cerebral vesicular protective structures, the blood–brain barrier, and the blood–brain tumor barrier (BTB). Although BSH has been reported to be selectively taken up by tumors, it is rapidly excreted from the body and cannot achieve a high tumor-to-normal brain ratio (T/N ratio) and tumor-to-blood ratio (T/B ratio). Despite the development of large-molecular weight boron compounds, such as polymers and nanoparticles, to enhance the permeation and retention effect, their effects remain insufficient for clinical use. To improve the efficiency of boron delivery to the tumor site, we propose combinations of self-assembled boron-containing polyanion polyethylene glycol-b-poly((closo-dodecaboranyl)thiomethylstyrene) (PEG-b-PMBSH) nanoparticles (295 ± 2.3 nm in aqueous media) coupled with cationic microbubble (B-MB)-assisted focused ultrasound (FUS) treatment. Upon FUS sonication (frequency = 1 MHz, pressure = 0.3–0.7 MPa, duty cycle = 0.5%, sonication = 1 min), B-MBs can simultaneously achieve safe BTB opening and boron drug delivery into tumor tissue. Compared with the MBs of the PEG-b-PMBSH mixture group (B + MBs), B-MBs showed 3- and 2.3-fold improvements in the T/N (4.4 ± 1.4 vs 1.3 ± 0.1) and T/B ratios (1.4 ± 0.6 vs 0.1 ± 0.1), respectively, after 4 min of FUS sonication. The spatial distribution of PEG-b-PMBSH was also improved by the complex of PEG-b-PMBSH with MBs. The findings presented herein, in combination with the expanding clinical application of FUS, may improve BNCT and treatment of GBM.
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