Arecoline induces activation of human oral fibroblasts by promoting macrophage secretion of exosomes containing miR-155-5p / 南方医科大学学报

OBJECTIVE@#To investigate the mechanism by which arecoline regulates the level of miR-155-5p in macrophage-secreted exosomes to induce the transformation of human oral mucosal fibroblasts (HOMFs) into fibroblast phenotype.@*METHODS@#Exosomes were harvested from human monocytic cell line THP-1 with or without arecoline treatment. The effects of arecoline-treated THP-1 cell culture supernatant (CS), THP-1-derived exosomes (EXO), exosome-depleted THP-1 cell supernatant (NES), miR-155-5p overexpression, and miR-155-5p inhibitor on migration ability of arecoline-treated HOMF cells were examined using Transwell migration assay. The polarization of THP-1 cells was detected using flow cytometry. DCFH-DA was used to detect the level of oxidative stress in the cells with different treatments. The mRNA and protein expressions of α- SMA, type I collagen and SOCS1 in the cells were detected with qRT-PCR and Western blotting.@*RESULTS@#Flow cytometry showed that arecoline-treated THP-1 cells exhibited obvious polarization from M0 to M1. Both the supernatant and exosomes from arecoline-treated THP-1 cells significantly enhanced the migration ability of HOMF cells, increased intracellular oxidative stress, up-regulated the expressions of miR-155- 5p and the mRNA and protein levels of α-SMA and type I collagen, and lowered the mRNA and protein expressions of SOCS1. In HOMF cells treated with exosomes from arecoline- treated THP-1 cells, overexpression of miR-155-5p significantly enhanced cell migration ability and increased cellular expressions of α-SMA and type I collagen, and miR-155-5p inhibitor caused the opposite changes.@*CONCLUSION@#Arecoline can up-regulate miR-155-5p expression in THP-1 cells and inhibit the expression of SOCS1 protein in HOMF cells via the exosome pathway, thus promoting the fibrotic phenotype transformation of HOMF cells.

Expression of anti-fungal peptide, β-defensin 118 in oral fibroblasts induced by C. albicans β-glucan-containing particles

Abstract Objective: Although oral fibroblasts are thought to have the potential to enhance host defenses against Candida albicans , it is unknown whether they are able to recognize Candida cell components to increase the expression of antifungal peptides, such as defensin factors, against Candida infection. Methodology: We performed expression profiles of defensin genes induced by heat-killed C. albicans in oral immortalized fibroblasts (GT1) using cDNA microarray analysis. From those results, quantitative RT-PCR was used to examine the effects of Candida β-glucan-containing particles (β-GPs) on β-Defensin 118 (DEFB 118) expression in oral mucosal cells. Furthermore, the antifungal activities of recombinant DEFB 118 against C. albicans and C. glabrata were investigated using fungicidal assays. Results: Microarray analysis showed that DEFB118, β-Defensin 129 (DEFB129), and α-Defensin 1 (DEFA1) genes were induced by heat-killed C. albicans and that their mRNA expressions were also significantly increased by live as well as heat-killed C. albicans . Next, we focused on DEFB118, and found that GT1, primary fibroblasts, and RT7 (oral immortalized keratinocytes) constitutively expressed DEFB118 mRNA expression in RT-PCR. Furthermore, C. albicans β-GPs significantly increased the expression of DEFB118 mRNA in GT1 and primary fibroblasts. Although DEFB118 mRNA expression in RT7 was significantly induced by both live and heat-killed C. albicans, C. albicans β-GPs failed to have an effect on that expression. Finally, recombinant DEFB118 significantly decreased the survival of both strains of C. albicans in a dose-dependent manner, whereas no effects were seen for both C. glabrata strains. Conclusion: DEFB118, induced by C. albicans β-GPs from oral fibroblasts, may play an important role in oral immune responses against C. albicans infection.

Single exposure of human oral mucosa fibroblasts to ultraviolet B radiation reduces proliferation and induces COX-2 expression and activation

The lip vermillion constitutes a transition tissue, between oral mucosa and skin, where oral mucosal cells from epithelial and connective tissue compartments are exposed to ultraviolet (UV) sunlight. Fibroblasts are abundant resident cells of the connective tissue which are key regulators of extracellular matrix composition, as well as, epithelial and endothelial cell function. UVB light, an inherent component of sunlight, causes several alterations in skin fibroblasts, including premature senescence and increased cyclooxygenase (COX)-2 expression. To assess if UVB irradiation had similar effects on fibroblasts derived from human oral mucosa (HOM), primary cultures of HOM fibroblasts were irradiated with a single dose of 30 or 60 mJ/cm²of UVB light or sham-irradiated. Fibroblast proliferation was assessed from 3 to 48 hrs after UVB-irradiation utilizing [³H]-thymidine incorporation and MTT assays. In addition, COX-2 mRNA expression was detected by RT-PCR, and PGE2 production was assessed using enzyme immunoassay from 0.5 to 24 hrs after UVB-irradiation. The results showed a significant decrease in proliferation of UVB-irradiated HOM fibroblasts as compared to controls as measured by both [³H]-thymidine incorporation and MTT assays (p<0.001). HOM fibroblasts had increased COX-2 mRNA expression at 0.5 and 12 hrs after irradiation, and PGE2 production was elevated at 12 and 24 hrs post-irradiation as compared to controls (p<0.05). The results showed an inhibitory effect of a single dose of UVB irradiation on HOM fibroblast proliferation with an increase in COX-2 expression and activation. Therefore, photodamaged fibroblasts may play and important role in the pathogenesis of UV-induced lesions of the lip.