Chitosan oligosaccharides alleviates the formation of atherosclerotic plaque through up-regulating core-fucosylation of SRBI in mice / 基础医学与临床

Objective To explore the mechanism of chitosan oligosaccharides(COS)in reducing atherosclerotic plaque formation from the perspective of protein glycosylation modification.Methods Totally 40 ApoE-/-mice were randomly divided into control group and COS group.The control group was given a high-fat diet for 12 weeks,and COS group was given a high-fat diet plus COS(gavage per day,500 mg/kg)for 12 weeks.Serum lipid detection,HE staining and Oil red O staining were used to detect plaque formation.Lectin chip,liquid chromatography tan-dem-mass spectrometry and ELISA were used to detect potential changes of glycoprotein in serum.Cholesterol ester outflow and free cholesterol ester determination experiment were used to evaluate the effect of changes in scavenger receptor class B type Ⅰ(SRBI)protein glycosylation modification site on cholesterol effluence in macrophages.Results COS significantly reduced the level of TC and LDL-C(P＜0.05)in mice,but had no effect on the level of TG,HDL-C,ApoA1 and ApoB100.The intima thickness and plaque size of the aorta were significantly thinner and smaller(P＜0.05)in the COS group compared with the control group.The molecular weight of lens culinaris ag-glutinin(LCA)binding protein with the most obvious change is 80-90 ku,and SRBI was one of them.COS promo-ted the cholesterol outflow and inhibited the accumulation of free cholesterol ester in RAW264.7 cell(P＜0.05).Knockdown or glycosylation site mutation with SRBI inhibited cholesterol outflow caused by COS,and increased the accumulation of intracellular free cholesterol(P＜0.05).Conclusions COS promotes lipid efflux by increasing SRBI glycosylation and expression,thereby alleviating atherosclerotic plaque formation.

Síntesis de glicoconjugados de albúmina sérica bovina y oligosacáridos de quitosano para el análisis de adhesión bacteriana / Synthesis of glycoconjugates of bovine albumin and chitosan oligosaccharides for the analysis of bacterial adhesion / Síntese de glicoconjugados de albumina serica bovina e oligossacarídeos de quitosana para análise de adesão bacteriana

Resumen El aumento de la resistencia a los antibióticos por parte de bacterias patógenas ha motivado la búsqueda de alternativas para disminuir su utilización. Dentro de las opciones propuestas se encuentra la terapia de antiadherencia, en la cual se utilizan moléculas análogas a los glicoepítopes que son reconocidos por las bacterias para impedir la unión de éstas al tejido celular. En este estudio se llevó a cabo la obtención de glicoconjugados por medio de la reacción de Maillard partiendo de albúmina sérica bovina (BSA) y oligosacáridos de quitosano (oligosacáridos sin ultrafiltrar, ultrafiltrados y ultrafiltrados acetilados), en proporción 1:1 (p/p) a tres temperaturas de incubación (50, 60 y 70 °C) por 30 min. La caracterización de los conjugados sintetizados se realizó utilizando electroforesis (SDS-PAGE), espectroscopía de infrarrojo y espectroscopía de fluorescencia. Se realizaron ensayos de reconocimiento usando aglutinina de germen de trigo (WGA) y bacterias [Escherichia coli (K88ac y K88+)]. La caracterización por medio de electroforesis y espectroscopía de infrarrojo evidenció la unión de los oligosacáridos de quitosano a la estructura de la BSA. Además, los ensayos evidenciaron el reconocimiento de las moléculas sintetizadas tanto por la lectina WGA como por las bacterias. Los glicoconjugados sintetizados sin ultrafiltrar ni acetilar mostraron resultados muy favorables en el reconocimiento por ambas bacterias, lo que constituye una ventaja práctica, ya que su implementación a mayor escala reduciría costos de producción

Abstract The increase in antibiotic resistance by pathogenic bacteria has motivated the search for alternatives to reduce the use of antibiotics. Among these alternatives is anti-adhesion therapy, in which molecules that mimic the glycoepitopes that recognise bacteria are used to prevent their binding to cellular tissue. In this study, glycoconjugates were obtained by means of the Maillard reaction starting from bovine serum albumin (BSA) and chitosan oligosaccharides (unfiltered oligosaccharides, ultrafiltered and acetylated ultrafiltered), in a ratio of 1:1 (w/w) at three incubation temperatures (50, 60 and 70 °C) per 30 min. The characterisation was performed using the techniques of electrophoresis (SDS-PAGE), infrared spectroscopy and fluorescence spectroscopy. Recognition assays were performed using wheat germ agglutinin (WGA) and Escherichia coli bacteria (K88ac and K88+). Characterisation by electrophoresis and infrared spectroscopy demonstrated the binding of chitosan oligosaccharides to the structure of BSA. In addition, the tests showed the recognition of the molecules synthesised by both the WGA lectin and the E. coli bacteria. The glycoconjugates synthesised without ultrafiltration or acetylation showed very favourable results in recognition with both bacteria, which is an advantage, since its implementation on a larger scale would reduce production costs.

Resumo O aumento da resistência aos antibióticos por bactérias patogênicas tem motivado a busca de alterna­tivas para reduzir seu uso. Entre essas alternativas está a terapia anti-adesão, na qual são utilizadas moléculas análogas aos glicoepítopos que são reconhecidas pelas bactérias para impedir sua união ao tecido celular. Neste estudo, os glicoconjugados foram obtidos por meio da reação de Maillard a partir de albumina sérica bovina (BSA) e oligossacarídeos de quitosana (oligossacarídeos não ultra­filtrados, ultrafiltrados e acetilados ultrafiltrados), na proporção de 1:1 (p/p) em três temperaturas de incubação (50, 60 e 70 °C) durante 30 min. A caracterização dos conjugados sintetizados foi realizada utilizando a eletroforese (SDS-PAGE), espectroscopia de infravermelho e espectroscopia de fluorescência. Os ensaios de reconhecimento foram realizados utilizando aglutinina de germe de trigo (WGA) e bactérias [Escherichia coli (K88ac e K88+)]. A caracterização por meio de eletroforese e espectroscopia de infravermelho demonstrou a união dos oligossacarídeos de quitosana à estrutura da BSA. Além disso, os testes evidenciaram o reconhecimento das moléculas sintetizadas tanto pela lectina WGA quanto pelas bactérias. Os glicoconjugados sintetizados sem ultrafiltração ou acetilação apresentaram resultados muito favoráveis no reconhecimento por ambas as bactérias, o que é uma vantagem, visto que sua implementação em maior escala reduziria custos de produção.

Comparative study of three biodegradable films for protein drug carrier / 国际生物医学工程杂志

Objective To prepare three kinds of biodegradable film materials used for protein drug carrier,and compare their degradation and drug release behavior.Methods Three different biodegradable and controlled release films,gelatin,chitosan oligosaccharides and crosslinked chitosan oligosaccharides films were prepared.Protein release behavior was determined by the Bradford.At the same time,degradation rate and swelling rate were tested,and the biocompatibility of film was investigated by MTT assay.Results The release time of crosslinked chitosan oligosaccharides film was 168 h,which was longer than that of chitosan oligosaccharides film,and different in different solution.The degradation rate and the swelling rate of crosslinked chitosan oligosaccharides was 60％ (360 h) and 110.45％,respectively,while the chitosan oligosaccharides membrane was 80％ (360 h) and 113.03％.The MTI assay revealed that the crosslinked chitosan oligosaccharides film had better biocompatibility.Conclusions By comparing different properties,the crosslinked chitosan oligosaccharides film is the best choice for protein drug carrier.

Effect of Chitosan Oligosaccharide on Enzymes for Cancer Chemoprevention / 대한암학회지

PURPOSE: Two types of chitosan oligosaccharides (COSs), COS I and COS II, were investigated for the effects on ascitic tumor and enzymes for cancer chemoprevention. MATERIALS AND METHODS: Chitosan oligosaccharides were administered once daily for 10 days after the tumor implantation. The change of body weight was observed for 20 days, and the survival rate of mice was determined after 21 days. Chitosan oligosaccharides were administered once daily for 10 days before the tumor implantation (1 106 cells). The number of ascitic tumor cells were measured at 6 days after tumor implantation. Chemopreventive potential of chitosan oligosaccharides was examined by the induction of quinone reductase and inhibition of cytochrome P450 1A1. RESULTS: Chitosan oligosaccharides exerted antitumor activity by inhibiting the growth of Ehrlich ascites tumor cells in vivo. Mice given Ehrlich cells and 10 or 100 mg/kg body weight of chitosan oligosaccharides had 33% survival after 21 days. Quinone reductase activity was increased with chitosan oligosaccharides. There were 26% and 33% inhibition in the activity of cytochrome P450 1A1 enzyme with the treatment of COS I and COS II, respectively. CONCLUSION: These results suggest that chitosan oligosaccharides has antitumor activity and cancer chemo preventive potential by inducing QR activity and inhibiting cytochrome P450 1A1.

Reactive Oxygen Radicals Generation and Apoptosis in HLF Cells Induced by PM10 / 环境与健康杂志

Objective The increasing evidences indicate that the inhalable particle matter (PM10) is responsible for respiratory and cardiovascular morbidity and mortality.Generation of superoxide anion,hydroxyl radical and apoptosis in HLF cells induced by PM10 were studied in this paper to present some data for elucidating the mechanism of effects of PM10.Methods The superoxide anion and hydroxyl radical were detected respectively by cytochrome C assay and apoptosis inspected with Annexin V-FITC/PI double staining by flow cytometry.Results PM10 could generate the superoxide anion and hydroxyl radical,with significant dose-dependent manners,and the levels of the superoxide anion as well as hydroxyl radical were decreased by chitosan oligosaccharides (COS),with the significant protection effects (P