title: In vitro evaluation of Lactobacillus plantarum DSMZ 12028 as a probiotic: emphasis on innate immunity.
abstract: In this study, we analyzed the probiotic potential of L. plantarum DSMZ 12028 in vitro using the pathogen E. coli K4 and a certified probiotic, L. paracasei F19, as controls. Adhesion to intestinal epithelial cells was evaluated using two cell lines, CaCo-2 and HT-29, through the plate dilution method. Moreover, the bacteria/epithelial dynamic interaction was continuously monitored using time-lapse microscopy. Expression of the innate immunity receptors, the TLRs, was evaluated by semi-quantitative PCR on an epithelial/bacteria co-culture. Real-time PCR was used to monitor expression of TLRs and cytokines in a monocytic cell line (THP-1) following bacterial exposure. The adherence of the strain to intestinal epithelial cells was comparable to that of the probiotic. Time-lapse experiments showed that E. coli K4 induced cell death while L. plantarum did not affect proliferation at a 10:1 bacteria/cell ratio. L. plantarum down-regulated TLR mRNAs with the exception of TLR2, while L. paracasei F19 and E. coli K4 caused a significant (p<0.05) up-regulation of TLR2 and 4, respectively. To simulate the activation of underlying immune cells in the lamina propria, we analyzed the immunomodulation of L. plantarum on a monocytic cell line, THP-1. Proinflammatory cytokines, such as TNFalpha, were increased by the presence of bacteria. The pathogen E. coli K4 also induced a strong up-regulation of proinflammatory cytokines, such as IL8, IL1beta and IL23. No differences were observed between experimental groups for IFNgamma, IL-10 and IL12p40. Overall, L. plantarum DSMZ 12028 demonstrated probiotic traits, inducing a proinflammatory response just above the "threshold level", which could prevent an inflammatory outcome, while inducing a higher state of alertness in the defense system of the host intestinal epithelial cells.
authors.affiliation: Department of Experimental Medicine, Biotechnology and Molecular Biology Section, Medical School, Second University of Naples, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Cammarota
authors.forename: Mario
authors.initials: M
authors.lastname: De Rosa
authors.forename: Antonietta
authors.initials: A
authors.lastname: Stellavato
authors.forename: Monica
authors.initials: M
authors.lastname: Lamberti
authors.forename: Iolanda
authors.initials: I
authors.lastname: Marzaioli
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Giuliano
mesh_terms: D001422:Bacterial Adhesion; D018938:Caco-2 Cells; D002460:Cell Line; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli; D015870:Gene Expression; D019073:HT29 Cells; D006801:Humans; D007113:Immunity, Innate; D056747:Immunomodulation; D048191:Lactiplantibacillus plantarum / Q000254:growth & development / Q000276:immunology*; D009000:Monocytes; D019936:Probiotics / Q000592:standards*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D051193:Toll-Like Receptors