Department of Biology, University of Naples Federico II-MSA-Via Cinthia, Naples, Italy.
PLoS One. 2013 Jul 23;8(7):e69102. doi: 10.1371/journal.pone.0069102. Print 2013.
It is now commonly accepted that the intestinal microbiota plays a crucial role in the gut physiology and homeostasis, and that both qualitative and quantitative alterations in the compositions of the gut flora exert profound effects on the host's intestinal cells. In spite of this, the details of the interaction between commensal bacteria and intestinal cells are still largely unknown and only in few cases the molecular mechanisms have been elucidated. Here we analyze the effects of molecules produced and secreted by Lactobacillus gasseri SF1183 on human intestinal HCT116 cells. L. gasseri is a well known species of lactic acid bacteria, commonly associated to the human intestine and SF1183 is a human strain previously isolated from an ileal biopsy of an healthy volunteer. SF1183 produces and secretes, in a growth phase-dependent way, molecule(s) able to drastically interfere with HCT116 cell proliferation. Although several attempts to purify and identify the bioactive molecule(s) have been so far unsuccessful, a partial characterization has indicated that it is smaller than 3 kDa, thermostable and of proteinaceous nature. L. gasseri molecule(s) stimulate a G1-phase arrest of the cell cycle by up-regulation of p21WAF1 rendering cells protected from intrinsic and extrinsic apoptosis. A L. gasseri-mediated reduction of apoptosis and of cell proliferation could be relevant in protecting epithelial barrier integrity and helping in reconstituting tissutal homeostasis.
现在普遍认为，肠道微生物群在肠道生理学和动态平衡中起着至关重要的作用，肠道菌群的组成在质量和数量上的改变都会对宿主的肠道细胞产生深远的影响。尽管如此，共生细菌和肠道细胞之间相互作用的细节在很大程度上仍然未知，只有在少数情况下阐明了其分子机制。在这里，我们分析了乳杆菌 SF1183 产生和分泌的分子对人肠 HCT116 细胞的影响。乳杆菌是一种众所周知的乳酸杆菌，通常与人类肠道有关，SF1183 是一种先前从健康志愿者回肠活检中分离出来的人类菌株。SF1183 以生长阶段依赖的方式产生和分泌能够严重干扰 HCT116 细胞增殖的分子。尽管目前已经尝试了多种纯化和鉴定生物活性分子的方法，但部分特征表明，该分子小于 3 kDa，具有热稳定性和蛋白质性质。乳杆菌的分子通过上调 p21WAF1 使细胞周期停滞在 G1 期，从而使细胞免受内在和外在凋亡的影响。乳杆菌介导的细胞凋亡和增殖减少可能有助于保护上皮屏障完整性并有助于重建组织内稳态。
