RESUMO
BACKGROUND: Intestinal homeostasis plays an important role in bacteria-derived complications in cirrhosis. Intestinal lymphocytes are responsible for immune effector functions and can be modulated by certain probiotics. We evaluate the interaction between Bifidobacterium pseudocatenulatum CECT7765 and intestinal lymphocytes in mice with cirrhosis. ANIMALS AND METHODS: Cirrhosis was induced by intragastrical administration of carbon tetrachloride in Balb/C mice. One week prior to laparotomy, animals received B. pseudocatenulatum CECT7765 (10(7), 10(9) or 10(10) cfu/daily) or placebo. Chemokine receptor and cytokine expression were evaluated in intestinal lymphocytes. Gut permeability was studied by FITC-LPS recovery in vivo. Luminal antigens, inflammation and functional markers were evaluated in liver samples. RESULTS: Bifidobacterium pseudocatenulatum CECT7765 decreased the expression of pro-inflammatory chemokine receptors CCR6, CCR9, CXCR3 and CXCR6 in intestinal lymphocytes from cirrhotic mice in a concentration-dependent manner. The bifidobacterial strain induced a shift towards an anti-inflammatory cytokine profile in this cell subset. B. pseudocatenulatum CECT7765-induced inflammatory modulation was TLR2-mediated, as in vitro TLR2 blockade inhibited the reduction of TNF-alpha and its receptors and the increase of IL-10 and IL-10 receptor secretion. The recovery rate of administered fluorescence-labelled endotoxin was significantly and dose-dependently lowered with the bifidobacterial strain. The reduced intestinal permeability was associated with a decreased burden of bacterial antigens in the liver of mice treated with B. pseudocatenulatum CECT7765. Liver function and inflammation were improved with the use of the bifidobacterial strain at the highest dose tested (10(10) cfu). CONCLUSION: Bifidobacterium pseudocatenulatum CECT7765 improves gut homeostasis and prevents gut-derived complications in experimental chronic liver disease.
Assuntos
Bifidobacterium , Microbioma Gastrointestinal , Cirrose Hepática/terapia , Linfócitos/microbiologia , Probióticos/administração & dosagem , Receptor 2 Toll-Like/genética , Animais , Tetracloreto de Carbono/administração & dosagem , Tetracloreto de Carbono/toxicidade , Modelos Animais de Doenças , Feminino , Homeostase , Interleucina-10/genética , Interleucina-10/metabolismo , Intestinos/citologia , Intestinos/microbiologia , Fígado/metabolismo , Fígado/microbiologia , Cirrose Hepática/induzido quimicamente , Linfócitos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Permeabilidade , Receptores CCR/genética , Receptores CCR/metabolismo , Receptores CCR6/genética , Receptores CCR6/metabolismo , Receptores CXCR/genética , Receptores CXCR/metabolismo , Receptores CXCR3/genética , Receptores CXCR3/metabolismo , Receptores CXCR6 , Receptor 2 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The process of bioethanol production from biomass comprises pretreatments and enzyme-mediated hydrolysis to convert lignocellulose into fermentable sugars. Because of the recalcitrant character of cellulose, the enzymatic hydrolysis is considered the major challenge in this process to be economically competitive. These technical difficulties highlight the need for the discovery of new enzymes to optimize and lower the cost of current technologies. Microorganisms have developed efficient systems for cellulose degradation. Among cellulolytic microbes, Thermobifida fusca possesses great physiological and cellulolytic characteristics (thermostability, high activity and tolerance to a broad pH range) making it an interesting organism to be studied from an applied perspective. In this review we describe the main enzymes/proteins produced by T.fusca (cellulases, xylanases, mannanase, manosidase, CBM33 and CelR), the effect of substrate on T. fusca proteome, enzyme improvement approaches, synergism between enzymes/proteins and artificial cellulosomes.
