No abstract

Clostridium difficile toxin A is known to cause deacetylation of tubulin proteins, which blocks microtubule formation and triggers barrier dysfunction in the gut. Based on our previous finding that the Clostridium difficile toxin A-dependent activation of histone deacetylase 6 (HDAC-6) is responsible for tubulin deacetylation and subsequent microtubule disassembly, we herein examined the possible effect of potassium acetate (PA; whose acetyl group prevents the binding of tubulin to HDAC-6) as a competitive/false substrate. Our results revealed that PA inhibited toxin A-induced deacetylation of tubulin and recovered toxin A-induced microtubule disassembly. In addition, PA treatment significantly decreased the production of IL-6 (a marker of inflamed tissue) in the toxin A-induced mouse enteritis model. An in vitro HDAC assay revealed that PA directly inhibited HDAC-6-mediated tubulin deacetylation, indicating that PA acted as a false substrate for HDAC-6. These results collectively indicate that PA treatment inhibits HDAC-6, thereby reducing the cytotoxicity and inflammatory responses caused by C. difficile toxin A.

, which causes pseudomembranous colitis, releases toxin A and toxin B. These toxins are considered to be the main causative agents for the disease pathogenesis, and their expression is associated with a marked increase of apoptosis in mucosal epithelial cells. Colonic epithelial cells are believed to form a physical barrier between the lumen and the submucosa, and abnormally increased mucosal epithelial cell apoptosis is considered to be an initial step in gut inflammation responses. Therefore, one approach to treating pseudomembranous colitis would be to develop agents that block the mucosal epithelial cell apoptosis caused by toxin A, thus restoring barrier function and curing inflammatory responses in the gut. We recently isolated an antimicrobial peptide, Periplanetasin-2 (Peri-2, YPCKLNLKLGKVPFH) from the American cockroach, whose extracts have shown great potential for clinical use. Here, we assessed whether Peri-2 could inhibit the cell toxicity and inflammation caused by toxin A. Indeed, in human colonocyte HT29 cells, Peri-2 inhibited the toxin A-induced decrease in cell proliferation and ameliorated the cell apoptosis induced by this toxin. Moreover, in the toxin A-induced mouse enteritis model, Peri-2 blocked the mucosal disruption and inflammatory response caused by toxin A. These results suggest that the American cockroach peptide Peri-2 could be a possible drug candidate for addressing the pseudomembranous colitis caused by toxin A.

Many reports have shown that crude extracts of the American cockroach have therapeutic effects on inflammation. In a previous study, our research group showed that an antimicrobial peptide (Periplanetasin-2) derived from the American cockroach via de novo transcriptome analysis inhibited apoptosis of human colonocytes and inflammatory responses of the mouse gut caused by Clostridium difficile toxin A. Here, we examined whether Periplanetasin-4 (Peri-4), another antimicrobial peptide identified via de novo transcriptome analysis of the American cockroach, could also inhibit the various toxicities induced by C. difficile toxin A. We found that Peri-4 significantly reduced the cell viability loss and cell apoptosis caused by toxin A in vitro. Peri-4 also ameliorated the severe inflammatory responses seen in the toxin A-induced mouse enteritis model, rescuing the villus disruption and interleukin-6 production induced by luminal injection of toxin A into the mouse gut. Mechanistically, we found that Peri-4 could reduce toxin A-induced reactive oxygen species production to inhibit the activations of p38MAPK and p21 , which are critical for the cell damages induced by toxin A. These results collectively suggest that the Peri-4 may be a potential therapeutic agent for treating toxin A-induced pseudomembranous colitis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Garlic (Allium sativum, L.) has a long history of reputed value and actual use for its medicinal, antimicrobial, and pesticidal properties. This study was conducted to find possible developments to natural food preservatives from garlic extracts. Garlic extracts were prepared from fresh crushed garlic and diluted with sterilize distilled water. The sensitivity test was conducted to investigate the antimicrobial effect of garlic extract against six strains of food poisoning bacteria such as Vol.41, No.7, pp.1102-1105, 1993. S. typhimurium은[5] 노현정, 신용서, 이갑상, 신미경, "쌀밥부패미생물 에 대한 녹차 물추출물의 항균활성", 한국식품과 학회지, 제28권, 제1호, pp.66-71, 1996.[6] 노현정, 신용서, 이갑상, 신미경, "녹차 물추출물 이 쌀밥의 품질 및 저장성 향상에 미치는 효과", 한국식품과학회지, 제28권, 제3권, pp.417-420, 1996.[7] D. M. Paul and J. H. Gerhard, "Antimicrobial activity of some edible plants: Lotus (Nelumbo nucifera), coffe, and others," J Food Prot, Vol.56, No.1, pp.66-68, 1993.[8] 김성환, 김남재, 최재수, 박종철, "꾸지뽕나무 잎 의 생리활성 및 HPLC에 의한 성분의 정량", 한국 영양식량학회지, 제22권, 제1호, pp.68-72, 1993. Vol.22, pp.96-98, 1971.[16] J. C. Dewit, S. Notermans, N. Gorin, and E. H.Kampelmacher, "Effect of garlic oil or onion oil on toxin production by Clostridium botulinum in meat Slurry," Journal of Food Protection, Vol.42, No.3, pp.222-224, 1979.[17] A. M. Saleem, and K. S. Al-delaimy, "Inhibition of Bacillus cereus by garlic extracts," J Food protection, Vol.45, pp.1007Vol.45, pp. -1009Vol.45, pp. , 1982.[18] C. J. Cavallito and J. H. Bailey, "Allicin, the antibacterial principle of Allium sativum.Ⅰ. Isolation, physical properties and antibacterial마늘추출물의 식중독균에 대한 항균검사 347 action," J Am Chem Soc, Vol.66, pp.1950-1951, 1944.[