Chitosan-triclosan particles modulate inflammatory signaling in gingival fibroblasts.

BACKGROUND AND OBJECTIVES: An important goal of periodontal therapy is the modulation of the inflammatory response. To this end, several pharmacological agents have been evaluated. Triclosan corresponds to an antibacterial and anti-inflammatory agent currently used in periodontal therapy. Chitosan is a natural polymer that may act as a drug delivery agent and exerts antibacterial and anti-inflammatory activities. Therefore, an association between both molecules might be useful to prevent inflammation and tissue destruction in periodontal tissues. MATERIAL AND METHODS: In the present study, we have generated chitosan-triclosan particles and evaluated their morphology, charge, biocompatibility and gene expression analysis in human gingival fibroblasts. RESULTS: The chitosan-triclosan particles size and Z potential were 129 ± 47 nm and 51 ± 17 mV respectively. Human gingival fibroblast viability was not affected by chitosan-triclosan. A total of 1533 genes were upregulated by interleukin (IL)-1ß. On the other hand, 943 were downregulated in fibroblasts stimulated with IL-1ß plus chitosan-triclosan particles. Fifty-one genes were identified as molecular targets upregulated by IL-1 ß and downregulated by the chitosan-triclosan particles. The gene ontology analysis revealed that these genes were enriched in categories related to biological processes, molecular function and cellular components. Furthermore, using real-time reverse transcription-polymerase chain reaction beta-actin, fibronectin, interleukin-6 and IL-1b genes were confirmed as targets upregulated by IL-1ß and downregulated by chitosan-triclosan particles. CONCLUSION: Our results show that chitosan-triclosan particles are able to modulate the inflammatory response in gingival fibroblasts. This effect might be useful in the prevention and/or treatment of inflammation in periodontal diseases.

Methylglyoxal and methylglyoxal-modified collagen as inducers of cellular injury in gingival connective tissue cells.

BACKGROUND AND OBJECTIVES: Methylglyoxal is a toxic product derived from glucose metabolism that plays a role in inflammation, diabetes and aging. In addition, the periodontal pathogen Tannerella forsythensis may also generate this compound. However, the effects of methylglyoxal on gingival cells are still poorly understood. In the present study, we have explored whether methylglyoxal or methylglyoxal-treated collagen may modulate cell viability, death and proliferation in gingival connective tissue cells. In addition, we have searched for inflammatory mediators secreted by cells upon exposure to these conditions. MATERIAL AND METHODS: Primary cultures of human gingival fibroblasts were stimulated with soluble methylglyoxal or cultured over a collagen matrix glycated by this agent. Cell viability was evaluated through the MTS assay. Cell death was assessed through DAPI nuclear staining, annexin V and propidium iodide assays. Cell proliferation was evaluated through double immunofluorescence for DAPI and Ki67. Protein levels of matrix metalloproteinases and cytokines were assessed through antibody arrays, enzyme-linked immunosorbent assay, real-time reverse transcription polymerase chain reaction and immunofluorescence. Statistical analysis was performed using the Kruskall-Wallis and Mann-Whitney tests. RESULTS: Soluble methylglyoxal, but not culture of gingival fibroblasts over a methylglyoxal-modified collagen matrix, induced a reduction on cell viability. Moreover, soluble methylglyoxal induced apoptotic cell death as indicated by DAPI nuclear staining, annexin V and propidium iodide assays. Neither soluble methylglyoxal, nor methylglyoxal-modified collagen modified cell proliferation. Using an antibody array, enzyme-linked immunosorbent assay and immunofluorescence assays, we determined that both, soluble methylglyoxal and methylglyoxal-modified collagen stimulated an increase in tissue inhibitor of metalloproteinase (TIMP)-1 protein levels. CONCLUSIONS: Soluble methylglyoxal is a highly cytotoxic compound that induces cell death through apoptosis in gingival fibroblasts. TIMP-1 is induced in these cells upon direct exposure to methylglyoxal or after culture of gingival fibroblasts over methylglyoxal-treated collagen. As TIMP-1 has been implicated in cell survival and matrix remodeling, we propose that increased TIMP-1 protein levels may be part of a protective response of gingival connective tissue cells upon exposure to methylglyoxal or after the interaction with the collagen matrix that has been modified by this agent.

Effects of chitosan particles in periodontal pathogens and gingival fibroblasts.

Chitosan is a naturally derived polymer with antimicrobial and anti-inflammatory properties. However, studies evaluating the role of chitosan in the control of periodontal pathogens and the responses of fibroblasts to inflammatory stimuli are lacking. In the present study, we analyzed whether chitosan particles may inhibit the growth of periodontal pathogens and modulate the inflammatory response in human gingival fibroblasts. Chitosan particles were generated through ionic gelation. They inhibited the growth of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans at 5 mg/mL. Conversely, IL-1ß strongly stimulated PGE2 protein levels in gingival fibroblasts, and chitosan inhibited this response at 50 µg/mL. IL-1ß-stimulated PGE2 production was dependent on the JNK pathway, and chitosan strongly inhibited this response. IL-1ß stimulated NF-κB activation, another signaling pathway involved in PGE2 production. However, chitosan particles were unable to modify NF-κB signaling. The present study shows that chitosan exerts a predominantly anti-inflammatory activity by modulating PGE2 levels through the JNK pathway, which may be useful in the prevention or treatment of periodontal inflammation.

NOX4-dependent ROS production by stromal mammary cells modulates epithelial MCF-7 cell migration.

BACKGROUND: The influence of the stromal microenvironment on the progression of epithelial cancers has been demonstrated. Unravelling the mechanisms by which stromal cells affect epithelial behaviour will contribute in understanding cellular malignancy. It has been proposed that redox environment has a role in the acquisition of malignancy. In this work, we studied the influence of epithelial cells on the stromal redox status and the consequence of this phenomenon on MCF-7 cell motility. METHODS: We analysed in a co-culture system, the effect of RMF-EG mammary stromal cells on the migratory capacity of MCF-7 cell line. To test whether the NOX-dependent stromal redox environment influences the epithelial migratory behaviour, we knocked down the expression of NOX4 using siRNA strategy. The effect of TGF-ß1 on NOX4 expression and activity was analysed by qPCR, and intracellular ROS production was measured by a fluorescent method. RESULTS: Migration of MCF-7 breast epithelial cells was stimulated when co-cultured with RMF-EG cells. This effect depends on stromal NOX4 expression that, in turn, is enhanced by epithelial soluble factors. Pre-treatment of stromal cells with TGF-ß1 enhanced this migratory stimulus by elevating NOX4 expression and intracellular ROS production. TGF-ß1 seems to be a major component of the epithelial soluble factors that stimulate NOX4 expression. CONCLUSIONS: Our results have identified that an increased stromal oxidative status, mainly provided by an elevated NOX4 expression, is a permissive element in the acquisition of epithelial migratory properties. The capacity of stromal cells to modify their intracellular ROS production, and accordingly, to increase epithelial motility, seems to depend on epithelial soluble factors among which TGF-ß1 have a decisive role.

Tumor necrosis factor-alpha-stimulated membrane type 1-matrix metalloproteinase production is modulated by epidermal growth factor receptor signaling in human gingival fibroblasts.

BACKGROUND AND OBJECTIVES: Membrane type 1-matrix metalloproteinase (MT1-MMP) is a collagenolytic enzyme involved in connective tissue remodeling. In periodontal tissues, either cytokines or growth factors regulate the production of proteolytic enzymes. Mice deficient in epidermal growth factor receptor (EGFR) show a reduced expression of MT1-MMP, suggesting that this receptor may play an important role in MT1-MMP production. The present study evaluated the role of the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and EGFR in the production of MT1-MMP in gingival fibroblasts. MATERIAL AND METHODS: Primary cultures of human gingival fibroblasts were cultured over plastic or a type I collagen matrix and stimulated with TNF-alpha and EGF. A selective EGFR inhibitor (AG1478) was used to interfere with this signaling pathway. Production of MT1-MMP and activation of proMMP-2 were studied using Western blot and gelatin zymography, respectively. Activation of EGFR signaling was assessed through immunoprecipitation and Western blot. Expression of EGFR ligands was determined through reverse transcriptase-polymerase chain reaction. RESULTS: Treatment of gingival fibroblasts cultured over a collagen matrix with TNF-alpha stimulated proMMP-2 activation and MT1-MMP production. However, after using AG1478, both responses were inhibited. Tumor necrosis factor-alpha induced EGFR transactivation and stimulated the expression of the mRNA for the EGFR ligands heparin binding-epidermal growth factor (HB-EGF) and transforming growth factor-alpha (TGF-alpha). CONCLUSIONS: The present study shows that TNF-alpha may stimulate MT1-MMP production through transactivation of EGFR. Tumor necrosis factor-alpha may also modulate the expression of the EGFR ligands TGF-alpha and HB-EGF. Production of MT1-MMP by TNF-alpha requires interaction with EGFR, suggesting that tissue remodeling is controlled by cross-communication between diverse signaling pathways in gingival fibroblasts.