RESUMEN
BACKGROUND & AIMS: Reducing symptoms of inflammatory bowel diseases (IBD) by dietary supplements represents more than ever an attractive clinical approach. Since the use of spore forming bacteria may offer interesting advantages, the aim of the study was to address the anti-inflammatory potential of Bacillus >subtilis strain PB6 (ATCC - PTA 6737) spores, provided as a powder preparation. METHODS: The immunomodulatory potential of strain PB6 was first characterized in vitro on human immunocompetent cells for both the commercial spore powder (Anaban™) and two phenotypic variants of the vegetative form. Assessment of the in vivo anti-inflammatory capacity of the standard spore powder and a variant spore powder preparation was performed using a mouse model of acute, TNBS-induced colitis. Performance was compared with the drug prednisolone, and was based on blinded macroscopic and histological scores, blood inflammatory markers and measurements of infiltration of mucosal neutrophils. RESULTS: Strain PB6 induced substantial levels of IL-10 but very low levels of IL-12, TNFα and IFNγ on human PBMC. Both spore powders prevented colitis as shown by significant reductions of near all inflammatory read-outs. CONCLUSION: B. subtilis strain PB6, provided as a preparation of spores, shows pre-clinical anti-inflammatory effects, suggesting further evaluation in a clinical intervention trial, e.g. with IBD type patients.
Asunto(s)
Antiinflamatorios/administración & dosificación , Bacillus subtilis , Colitis/prevención & control , Probióticos/administración & dosificación , Animales , Peso Corporal , Línea Celular , Colitis/inducido químicamente , Colitis/patología , Modelos Animales de Enfermedad , Humanos , Enfermedades Inflamatorias del Intestino/microbiología , Enfermedades Inflamatorias del Intestino/prevención & control , Interferón gamma/sangre , Interleucina-10/sangre , Interleucina-12/sangre , Leucocitos Mononucleares/metabolismo , Leucocitos Mononucleares/microbiología , Ratones , Neutrófilos/patología , Proteína Amiloide A Sérica/análisis , Esporas Bacterianas , Ácido Trinitrobencenosulfónico/efectos adversos , Factor de Necrosis Tumoral alfa/sangreRESUMEN
Pseudodesmin A is a cyclic lipodepsipeptide (CLP) of the viscosin group with a moderate in vitro biological activity. For several CLPs, including members of this group, this activity has been related to the ability to form ion pores in cellular membranes. As their size does not allow individual CLPs to span the membrane bilayer, individual monomers must somehow assemble into a larger structure. NMR spectroscopy has been used to demonstrate that in chloroform and other apolar organic solvents, pseudodesmin A monomers assemble into a supramolecular structure. These self-assembled structures can become sufficiently large to span the membrane bilayer as demonstrated with translational diffusion NMR spectroscopic measurements. With the aim to obtain more insight into the structural nature of this assembly, the solution conformation of pseudodesmin A was first determined by using ROESY (rOe) restraints measured in acetonitrile, in which no self-association occurs. The structure, which is found to be mostly similar to the previously described crystal structure, is shown to be retained within the supramolecular complex. Intermolecular rOe contacts obtained in chloroform together with chemical shift perturbation data provides structural insight into the organization of the self-associated complex. Based upon this analysis, a model for the organization of pseudodesmin A monomers in the supramolecular assembly is proposed, which is in agreement with the formation of bilayer spanning hydrophilic pores and provides the basis for a structure-function relationship for this type of CLPs. Finally, it is demonstrated that the differences previously reported between the crystal and solution conformation of the white line inducing principle (WLIP), a close analogue of pseudodesmin A, are the result of the use of dimethyl sulfoxide as solvent, whose strong hydrogen-bonding capacity induces conformational exchange.
Asunto(s)
Lipopéptidos/química , Lipopéptidos/metabolismo , Péptidos Cíclicos/química , Péptidos Cíclicos/metabolismo , Acetonitrilos/química , Cloroformo/química , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Porosidad , Conformación Proteica , Soluciones , Solventes/químicaRESUMEN
An efficient convergent approach has been developed for the construction of novel, nonnatural polysubstituted carbohydrate-based macrolides. A key step in the synthesis is the formation of the macrocyclic ring via a ring-closing metathesis reaction. The obtained macrolide analogues have been screened for biological activity against gram-positive and gram-negative bacteria, yeasts, and molds.
Asunto(s)
Antibacterianos/síntesis química , Carbohidratos/química , Macrólidos/síntesis química , Antibacterianos/química , Ciclización , Macrólidos/química , Espectroscopía de Resonancia Magnética , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
We report that the antimalarial drug artemisinin inhibits hepatitis C virus (HCV) replicon replication in a dose-dependent manner in two replicon constructs at concentrations that have no effect on the proliferation of the exponentially growing host cells. The 50% effective concentration (EC(50)) for inhibition of HCV subgenomic replicon replication in Huh 5-2 cells (luciferase assay) by artemisinin was 78+/-21 microM. Hemin, an iron donor, was recently reported to inhibit HCV replicon replication [mediated by inhibition of the viral polymerase (C. Fillebeen, A.M. Rivas-Estilla, M. Bisaillon, P. Ponka, M. Muckenthaler, M.W. Hentze, A.E. Koromilas, K. Pantopoulos, Iron inactivates the RNA polymerase NS5B and suppresses subgenomic replication of hepatitis C virus, J. Biol. Chem. 280 (2005) 9049-9057.)] at a concentration that had no adverse effect on the host cells. When combined, artemisinin and hemin resulted, over a broad concentration range, in a pronounced synergistic antiviral activity. Also at a concentration (2 microM) that alone had no effect on HCV replication, hemin still potentiated the anti-HCV activity of artemisinin.
Asunto(s)
Artemisininas/farmacología , Hemina/farmacología , Hepacivirus/efectos de los fármacos , Hepacivirus/fisiología , Sesquiterpenos/farmacología , Antimaláricos/farmacología , Línea Celular , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Humanos , Concentración 50 Inhibidora , Replicón/efectos de los fármacos , Replicación Viral/efectos de los fármacosRESUMEN
A small library of bicyclic carbohydrate derivatives was synthesized and screened. A strong and selective activity against cytomegalovirus was found. Structure-activity relationship for this new type of antivirals is discussed.
Asunto(s)
Antivirales , Compuestos Bicíclicos con Puentes , Pulmón/efectos de los fármacos , Antivirales/síntesis química , Antivirales/química , Antivirales/farmacología , Compuestos Bicíclicos con Puentes/síntesis química , Compuestos Bicíclicos con Puentes/química , Compuestos Bicíclicos con Puentes/farmacología , Carbohidratos/síntesis química , Carbohidratos/química , Carbohidratos/farmacología , Células Cultivadas/efectos de los fármacos , Citomegalovirus/patogenicidad , Infecciones por Citomegalovirus/tratamiento farmacológico , Infecciones por Citomegalovirus/virología , Humanos , Pulmón/embriología , Pulmón/virología , Estructura Molecular , Relación Estructura-ActividadRESUMEN
The artemisinin derivative beta-artemether, an anti-malarial, was evaluated for its toxicity and tolerability in a 2-week, multiple-dose study in dogs. Eight beagle dogs (4 females, 4 males) were given beta-artemether by oral gavage 3 times daily at 45 mg/kg/dosing (a total daily dose-level of 135 mg/kg) for 2 weeks. This beta-artemether dose regime was well tolerated. Body weight changes were normal although feed consumption during the treatment period reduced compared to that of the pre-trial period. Clinical signs were transient spells of soft to liquid feces. On completion of the treatment period, the animals were sacrificed and submitted to a full macroscopic post-mortem examination. Designated organs were weighed and a complete light microscopic examination was performed on 43 selected tissues from 1 animal per sex, and on the liver, kidneys, thymus, mandibular lymph nodes and lungs of the three other animals per sex. Major findings were high liver weight and histopathologic findings of slight diffuse hepatocellular hypertrophy and distal tubular dilatation, together with flattened epithelium, in the kidneys. With the dose regime used in this trial beta-artemether produced no clinical or apparent histopathological signs of neurotoxicity in dogs.
Asunto(s)
Antimaláricos/toxicidad , Artemisininas/toxicidad , Pruebas de Toxicidad , Administración Oral , Animales , Arteméter , Aumento de la Célula/efectos de los fármacos , Perros , Ingestión de Alimentos/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Femenino , Hepatocitos/efectos de los fármacos , Hepatocitos/patología , Hipertrofia/inducido químicamente , Hipertrofia/patología , Túbulos Renales Distales/efectos de los fármacos , Túbulos Renales Distales/patología , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Tamaño de los Órganos/efectos de los fármacosRESUMEN
[reaction: see text] An efficient convergent approach has been developed for the construction of novel, non-natural, carbohydrate-based macrolides. The key step in the synthesis is the formation of the macrocyclic ring via a ring-closing metathesis reaction. The obtained macrolide analogues have been screened for biological activity against gram-positive and gram-negative bacteria, including resistant strains, yeasts, and molds.