Effect of catestatin on inhibiting C.albicans biofilm formation by down-regulating the expression of HWP1 / 中国感染与化疗杂志

ABSTRACT

Objective To investigate whether catestatin (bovine chromogranin A 344-364) can inhibit the biofilm formation of Candida albicans and examine its relationship with the expression of adhesion gene HWP1.Methods Clinical strains and standard strain ATCC 10231 of C.albicans were studied.XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] method was used to assess the ability of C.albicans biofilm formation.Antifungal activity against planktonic Candida ceils was evaluated in terms of minimum inhibitory concentrations (MICs) according to the description in CLSI-M27-A3.XTT assay and colony count were used to assess the effect of catestatin on inhibiting C.albicans biofilm formation.The lowest concentration showing 50 ％ inhibition on biofilm formation (BIC50) was decided by calculating the metabolic activity.The adhesion of C.albicans reduced by catestatin was visualized under an inverted microscope and quantified by colony count.The expression of HWP1 was analyzed by RT-PCR.One-way analysis of variance (ANOVA) and Dunnett's T3 test were used to compare the results.Results Clinical strains and standard strain ATCC 10231 of C.albicans showed strong ability in forming biofilm.Catestatin exhibited MICs ranging from 40 μmol/L to 80 μmol/L against planktonic C.albicans cells,and BIC50 of 80-160 μmol/L in inhibiting C.albicans biofilm formation.Catestatin reduced the adhesion of C.albicans.The colony forming unit (CFU) was 27 822.22-±-2 472.74 in blank control group,while the CFU was 5 355.55± 1 264.03,11 377.78±2 232.58,17 488.89±1 136.27,22 377.78±3 521.99,and 26 044.44±1 329.57 in the presence of 160,80,40,20,and 10 μmol/L catestatin,respectively (F=147.018,P=0.001).The difference between control group and 160,80,and 40 μmol/L catestatin was statistically significant (P＜0.05).RT-PCR found the expression of HWP1 in the presence of 160 μmol/L catestatin was about 12.24％ of that in blank control group.Conclusions Catestatin can effectively prevent C.albicans biofilm formation.This effect may be related to the down-regulated expression of adhesion gene HWP1 by catestatin,which results in reduced adhesion of C.albicans.Promising clinical prospect is expected for this finding.