IADR Abstract Archives
Hypoxia and the hypoxia mimetic agent L-mimosine can increase the production of angiopoietin-like 4 in oral cells
Objectives: Angiopoietin-like 4 can modulate angiogenesis and resorption of hard tissue. However, the role of Angiopoietin-like 4 in oral tissues such as the dentin-pulp complex and the periodontium is unclear. We hypothesized that hypoxia and the hypoxia mimetic agents can induce angiopoietin-like 4 production in the oral tissues such as the dental pulp, the gingiva, and the periodontal ligament.
Methods: We treated monolayer and spheroid cultures of primary human cells derived from dental pulp, gingiva, and periodontal ligament with hypoxia or the hypoxia mimetic agent L-mimosine (L-MIM). Furthermore, tooth slice cultures in the presence of hypoxia or L-MIM were done. Cultures under normoxia served as control. Angiopoietin-like 4 mRNA levels were assessed with reverse transcription qPCR. Angiopoietin-like 4 protein levels in the supernatants were measured with ELISA. Echinomycin was used to reveal the involvement of hypoxia inducible factor-1 alpha (HIF-1alpha).
Results: Our data show that angiopoietin-like 4 mRNA and protein levels were increased upon treatment with hypoxia and L-MIM in monolayer cultures of cells derived from dental pulp, gingiva, periodontal ligament. Echinomycin prevented the impact on angiopoietin-like 4 production. Also in spheroid cultures an increase in angiopoietin-like 4 mRNA and protein was measurable. In tooth slice cultures the dental pulp tissue produced and released angiopoietin-like 4 under normoxia, hypoxia, and in the presence of L-MIM. However, the results of monolayer and spheroid cultures do not directly translate into the situation in the dental pulp complex. We observed a trend for an increase of angiopoietin-like 4 mRNA levels but a trend for a decrease in the protein levels of the culture supernatants. Both did not reach the level of significance.
Conclusions: Our results show that hypoxia and the hypoxia mimetic agent L-MIM can stimulate angiopoietin-like 4 production in cells derived from dental pulp, gingiva, and periodontal ligament. This cellular response involves HIF-1alpha signaling. Interestingly the response of oral cells depends on the culture model. Preclinical studies will reveal the role of angiopoietin-like 4 in oral tissues.
Methods: We treated monolayer and spheroid cultures of primary human cells derived from dental pulp, gingiva, and periodontal ligament with hypoxia or the hypoxia mimetic agent L-mimosine (L-MIM). Furthermore, tooth slice cultures in the presence of hypoxia or L-MIM were done. Cultures under normoxia served as control. Angiopoietin-like 4 mRNA levels were assessed with reverse transcription qPCR. Angiopoietin-like 4 protein levels in the supernatants were measured with ELISA. Echinomycin was used to reveal the involvement of hypoxia inducible factor-1 alpha (HIF-1alpha).
Results: Our data show that angiopoietin-like 4 mRNA and protein levels were increased upon treatment with hypoxia and L-MIM in monolayer cultures of cells derived from dental pulp, gingiva, periodontal ligament. Echinomycin prevented the impact on angiopoietin-like 4 production. Also in spheroid cultures an increase in angiopoietin-like 4 mRNA and protein was measurable. In tooth slice cultures the dental pulp tissue produced and released angiopoietin-like 4 under normoxia, hypoxia, and in the presence of L-MIM. However, the results of monolayer and spheroid cultures do not directly translate into the situation in the dental pulp complex. We observed a trend for an increase of angiopoietin-like 4 mRNA levels but a trend for a decrease in the protein levels of the culture supernatants. Both did not reach the level of significance.
Conclusions: Our results show that hypoxia and the hypoxia mimetic agent L-MIM can stimulate angiopoietin-like 4 production in cells derived from dental pulp, gingiva, and periodontal ligament. This cellular response involves HIF-1alpha signaling. Interestingly the response of oral cells depends on the culture model. Preclinical studies will reveal the role of angiopoietin-like 4 in oral tissues.