A novel LncRNA SPIRE1/miR-181a-5p/PRLR axis in mandibular bone marrow-derived mesenchymal stem cells regulates the Th17/Treg immune balance through the JAK/STAT3 pathway in periodontitis.

Periodontitis is a microbial-related chronic inflammatory disease associated with imbalanced differentiation of Th17 cells and Treg cells. Bone marrow-derived mesenchymal stem cells (BM-MSCs) possess wide immunoregulatory properties. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) contribute to the immunomodulation in the pathological mechanisms of inflammatory diseases. However, critical lncRNAs/miRNAs involved in immunomodulation of mandibular BM-MSCs largely remain to be identified. Here, we explored the molecular mechanisms behind the defective immunomodulatory ability of mandibular BM-MSCs under the periodontitis settings. We found that mandibular BM-MSCs from P. gingivalis-induced periodontitis mice had significantly reduced expression of LncRNA SPIRE1 than that from normal control mice. LncRNA SPIRE1 knockdown in normal BM-MSCs caused Th17/Treg cell differentiation imbalance during the coculturing of BM-MSCs and CD4 T cells. In addition, LncRNA SPIRE1 was identified as a competitive endogenous RNA that sponges miR-181a-5p in BM-MSCs. Moreover, miR-181a-5p inhibition attenuated the impact of LncRNA SPIRE1 knockdown on the ability of BM-MSCs in modulating Th17/Treg balance. Prolactin receptor (PRLR) was validated as a downstream target of miR-181a-5p. Notably, targeted knockdown of LncRNA SPIRE1 or PRLR or transfection of miR-181a-5p mimics activated the JAK/STAT3 signaling in normal BM-MSCs, while treatment with STAT3 inhibitor C188-9 restored the immunomodulatory properties of periodontitis-associated BM-MSCs. Furthermore, BM-MSCs with miR-181a-5p inhibition or PRLR-overexpression showed enhanced in vivo immunosuppressive properties in the periodontitis mouse model. Our results indicate that the JAK/STAT3 pathway is involved in the immunoregulation of BM-MSCs, and provide critical insights into the development of novel targeted therapies against periodontitis.

Taxifolin Protects Dental Pulp Stem Cells under Hypoxia and Inflammation Conditions.

BACKGROUND: Dental pulp stem cells (DPSCs) are a unique source for future clinical application in dentistry such as periodontology or endodontics. However, DPSCs are prone to apoptosis under abnormal conditions. Taxifolin is a natural flavonoid and possesses many pharmacological activities including anti-hypoxic and anti-inflammatory. We aimed to elucidate the mechanisms of taxifolin protects DPSC under hypoxia and inflammatory conditions. METHODS: DPSCs from human dental pulp tissue was purchased from Lonza (cat. no. PT-5025. Basel, Switzerland)) and identified by DPSC's biomarkers. DPSC differentiation in vitro following the manufacturers' instructions. ARS staining and Oil red staining verify the efficiency of differentiation in vitro after 2 weeks. The changes of various genes and proteins were identified by Q-PCR and western-blot, respectively. Cell viability was determined by the CCK-8 method, while apoptosis was determined by Annexin V/PI staining. RESULTS: DPSC differentiation in vitro shows that hypoxia and TNF-α synergistically inhibit the survival and osteogenesis of DPSCs. A final concentration of 10 µM Taxifolin can significantly reduce the apoptosis of DPSCs under inflammation and hypoxia conditions. Taxifolin substantially increases carbonic anhydrase IX (CA9) expression but not HIF1a, and inhibitions of CA9 expression nullify the protective role of taxifolin under hypoxia and inflammatory condition. CONCLUSION: Taxifolin significantly increased the expression of CA9 when it inhibits DPSC apoptosis and taxifolin synergistically to protect DPSCs against apoptosis with CA9 under hypoxia and inflammatory conditions. Taxifolin can be used as a potential drug for clinical treatment of DPSC-related diseases.