Human Epithelial Cell Line HT-29 Research Articles

Determination of the Anti-inflammatory and Anti-microbial Activity of a Cosmetic Product Silver Stop® Cream

The anti-inflammatory and antimicrobial effects of a cream containing extracts of African geranium (Pelargonium sidoides DC.), black elderberry (Sambucus nigra L.) and St. John's wort (Hypericum perforatum L.) in colloidal nanosilver (AgNPs) at a concentration of 30 ppm, denoted as SILVER STOP® cream (SS® cream) was examined In vitro. The research was performed with Staphylococcus aureus (ATCC-6538 and two clinical strains). Suspension tests for determination the time of antimicrobial action of SS® cream were used. SS® cream showed significant antimicrobial activity. In suspension with a density of 104 cells.mL-1S. aureus died after 60 minutes of exposure to SS® cream. In suspension with concentration of 106 cells.mL-1, after 2 h only single cells remained viable. The anti-inflammatory effect was evaluated using human epithelial cell line HT-29, incubated with a type strain of S. aureus. After treatment with SS® cream, results have shown a statistically significant reduction of the levels of the pro-inflammatory cytokinesIL-6, IL-8, IP-10 and IL-1β.

In-vitro characterization of potentially probiotic Lactobacillus strains isolated from human microbiota: interaction with pathogenic bacteria and the enteric cell line HT29

Among the various tests commonly used for selecting probiotic microorganisms, the tolerance to gastrointestinal transit conditions remains being commonly used to evaluate the probiotic potential of the strains. Besides, the adhesion to epithelial cells and the competition with pathogens constitute significant traits for evaluating the colonization ability and functional performance of candidate strains. In this study, a total of 13 lactic acid bacteria strains isolated from human feces were first identified by biochemical tests and 16S rRNA gene sequencing, and then characterized in vitro for their tolerance to gastrointestinal conditions, hemolytic activity, and antibiotics sensibility. The isolates were identified as Lactobacillus fermentum (06), Lactobacillus rhamnosus (04), Lactobacillus plantarum (02), and Lactobacillus salivarius (01). The adhesion to epithelial cells HT29 was shown to be a strain-dependent character. L. fermentum 88 and L. plantarum 9, being the ones showing higher adhesion values. They were further characterized by determining their antimicrobial activity, hydrophobicity, co-aggregation, antioxidant activity, as well as the ability to inhibit the adhesion of pathogens to the human epithelial cell line HT29. Moreover, these two strains were able to reduce the adhesion of Escherichia coli to HT29 cells, although they failed for inhibiting the adhesion of other pathogens such as Cronobacter sakazaki or Salmonella enterica. These results point out the importance of considering the ecological fitness of the strains in selecting probiotic bacteria and the potential of some of the analyzed strains for the development of food products.

Anti-Flagellin antibodies dampen TLR5 and NLRC4 innate immune responses to flagellin

Abstract The host immune system is constantly exposed to diverse microbial ligands, including flagellin (FliC; a ligand for TLR5 and NLRC4) and lipopolysaccharide (LPS; a ligand for TLR4), whose ability to induce immune tolerance to subsequent exposure is well-documented in vitro. In this study, we investigated the extent to which FliC and LPS could induce immune cross-tolerance to one another in vivo, as well as the interaction between the innate and adaptive immune response to FliC. Mice pre-treated with LPS displayed attenuated serum keratinocyte-derived chemokine [KC; alias interleukin (IL)-8] and IL-6 response to FliC; however, the administration of FliC followed by LPS instead resulted in an additive response. LPS also augmented the serum IL-18 response to FliC; the increment was more pronounced when LPS was administered before, than after, FliC. Intriguingly, the generation of anti-FliC antibodies was notably impaired in mice sequentially challenged with LPS and FliC, compared to mice given only FliC. A strong negative correlation between high anti-FliC titer and reduced KC, IL-6 and IL-18 responses to FliC re-challenge was observed in these mice, suggesting that adaptive immunity could tolerize TLR5 and NLRC4. Indeed, the serum from WT mice with high anti-FliC titer, but not Rag1KO mice, was able to dampen FliC-induced secretion of IL-8 from the human epithelial cell line HT-29. These observations may be relevant in the context of bacterial infection, as we demonstrated that anti-FliC response are protective against systemic infection by Salmonella typhimurium. Taken together, our study delineates a distinct co-operative and reciprocal interaction between the innate and adaptive arms of immunity in modulating their responses to FliC.

Effects of increased cellular zinc levels on gene and protein expression in HT-29 cells

High cellular zinc concentrations lead to impairments in ATP synthesis and cell cycle control particularly in neurons and epithelial cells. The molecular basis for these dysfunctions is still not fully elucidated. Here we analyzed the effects of a high zinc exposure (10 ppm) on gene and protein expression in the human epithelial cell line HT-29. Of the 1176 genes analyzed with cDNA arrays, nine differentially expressed genes were identified. Proteome analysis based on 1310 detected proteins identified 11 molecular targets. Most of the identified genes/proteins have not been linked to cellular zinc status before (e.g. PEC-60, R-ras3). More than half of the targets participate in ATP production or stress response. Therefore, it appears that higher zinc concentrations mediate their effects mainly via impairments in cellular energy metabolism and stress response.

Opsonization of HIV-1 by semen complement enhances infection of human epithelial cells.

In the present study we demonstrate that both X4- and R5-tropic HIV-1 strains are able to infect the human epithelial cell line HT-29. Infection was enhanced 2-fold when HIV was added to semen before contact with the cell cultures. The enhancing effect of semen was complement dependent, as evidenced by blockage of generation of C3a/C3a(desArg) in semen by heat or EDTA treatment of semen and suppression of semen-dependent enhancement with mAbs directed to complement receptor type 3 (CD11b/CD18) and soluble CD16. Infection of HT-29 cells was assessed by the release of p24 Ag in cultures and semiquantitative PCR of the HIV-1 pol gene. Inhibition of infection of HT-29 by stromal cell-derived factor 1 was decreased in the case of semen-opsonized X4- and R5-tropic virus compared with unopsonized virus. In contrast, inhibition of infection by RANTES was increased for opsonized X4-tropic HIV-1 compared with unopsonized virus. Taken together these observations indicate that activation of complement in semen may play an enhancing role in mucosal transmission of HIV-1 by facilitating infection of epithelial cells and/or enhancing infection of complement receptor-expressing target cells in the mucosa.