1. Angiopoietin-like 4 production upon treatment with hypoxia and L-mimosine in periodontal fibroblasts.
- Author
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Janjić K, Schellner A, Engenhart A, Kernstock K, Schädl B, Moritz A, and Agis H
- Subjects
- Angiopoietins, Cells, Cultured, Fibroblasts, Humans, Hypoxia-Inducible Factor 1, alpha Subunit metabolism, Periodontal Ligament metabolism, Angiopoietin-Like Protein 4 metabolism, Escherichia coli, Hypoxia, Mimosine pharmacology
- Abstract
Background and Objective: A key factor in the modulation of angiogenesis as well as in bone resorption is angiopoietin-like 4. However, the role of angiopoietin-like 4 in periodontal tissue is unknown. Here, we hypothesized that hypoxia and the hypoxia mimetic agent L-mimosine can induce the production of angiopoietin-like 4 in periodontal fibroblasts., Methods: Human periodontal ligament fibroblasts (PDLF) were cultured in monolayer and spheroid cultures. The cultures were incubated in the presence of hypoxia or L-mimosine. Angiopoietin-like 4 mRNA and protein levels were measured by qPCR and ELISA, respectively. Also, the impact of Lipopolysaccharides of E. coli and P. gingivalis, interleukin (IL)-1β and tumor necrosis factor (TNF)α was evaluated. Furthermore, we tested dependency on hypoxia-inducible factor (HIF)-1 activity by Western blotting for HIF-1 and inhibitor studies with echinomycin. Potential autocrine effects were assessed by exposure of PDLF to recombinant angiopoietin-like 4 in full length, C-terminal and N-terminal fragments. The impact on viability, DNA synthesis, alkaline phosphatase, and matrix mineralization was evaluated., Results: Both hypoxia and L-mimosine elevated angiopoietin-like 4 mRNA and protein levels in monolayer cultures of PDLF. HIF-1 was elevated after both hypoxia and L-mimosine treatment. LPS, IL-1β, and TNFα did not modulate angiopoietin-like 4 levels significantly. Addition of echinomycin in the cultures inhibited the production of angiopoietin-like 4. In spheroid cultures of PDLF, the increase did not reach the level of significance at mRNA and protein levels. Angiopoietin-like 4 in full length, C-terminal, and N-terminal fragments did not modulate viability, DNA synthesis, alkaline phosphatase, and matrix mineralization., Conclusion: Overall, we found that hypoxia and the hypoxia mimetic agent L-mimosine can stimulate angiopoietin-like 4 production in monolayer cultures of PDLF. This increase depends on HIF-1 activity. Future studies will reveal how the modulation of angiopoietin-like 4 in the periodontium contributes to periodontal disease and regeneration., (© 2019 The Authors. Journal of Periodontal Research Published by John Wiley & Sons Ltd.)
- Published
- 2019
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