Abstract
BackgroundCritical tissues that undergo regeneration in periodontal tissue are of mesenchymal origin; thus, investigating the regulatory mechanisms underlying the fate of periodontal ligament stem cells could be beneficial for application in periodontal tissue regeneration. Nitric oxide (NO) regulates many biological processes in developing embryos and adult stem cells. The present study was designed to investigate the effects of NO on the function of human periodontal ligament stem cells (PDLSCs) as well as to elucidate the underlying molecular mechanisms.MethodsImmunofluorescent staining and flow cytometry were used for stem cell identification. Western blot, reverse transcription polymerase chain reaction (RT-PCR), immunofluorescent staining, and flow cytometry were used to examine the expression of NO-synthesizing enzymes. The proliferative capacity of PDLSCs was determined by EdU assays. The osteogenic potential of PDLSCs was tested using alkaline phosphatase (ALP) staining, Alizarin Red staining, and calcium concentration detection. Oil Red O staining was used to analyze the adipogenic ability. Western blot, RT-PCR, and staining were used to examine the signaling pathway.ResultsHuman PDLSCs expressed both inducible NO synthase (iNOS) and endothelial NO synthase (eNOS) and produced NO. Blocking the generation of NO with the NOS inhibitor l-NG-monomethyl arginine (l-NMMA) had no influence on PDLSC proliferation and apoptosis but significantly attenuated the osteogenic differentiation capacity and stimulated the adipogenic differentiation capacity of PDLSCs. Increasing the physiological level of NO with NO donor sodium nitroprusside (SNP) significantly promoted the osteogenic differentiation capacity but reduced the adipogenic differentiation capacity of PDLSCs. NO balances the osteoblast and adipocyte lineage differentiation in periodontal ligament stem cells via the c-Jun N-terminal kinase (JNK)/mitogen-activated protein kinase (MAPK) signaling pathway.ConclusionsNO is essential for maintaining the balance between osteoblasts and adipocytes in PDLSCs via the JNK/MAPK signaling pathway.Graphical NO balances osteoblast and adipocyte lineage differentiation via JNK/MAPK signaling pathway
Highlights
Critical tissues that undergo regeneration in periodontal tissue are of mesenchymal origin; investigating the regulatory mechanisms underlying the fate of periodontal ligament stem cells could be beneficial for application in periodontal tissue regeneration
Since both inducible NO synthase (NOS) (iNOS) and endothelial NOS (eNOS) have been reported to be expressed in human umbilical vein endothelial cells (HUVECs) [13] and neuronal NOS (nNOS) is expressed in glioma cell (U251) [14], we used HUVECs and U251 as a positive control
We found that periodontal ligament stem cells (PDLSCs) highly expressed iNOS and eNOS but very little nNOS, as shown by Western blot, immunofluorescent staining, and flow cytometry (Fig. 1c–e)
Summary
Critical tissues that undergo regeneration in periodontal tissue are of mesenchymal origin; investigating the regulatory mechanisms underlying the fate of periodontal ligament stem cells could be beneficial for application in periodontal tissue regeneration. Nitric oxide (NO) regulates many biological processes in developing embryos and adult stem cells. Many signaling pathways and molecules have been identified that regulate the differentiation of mesenchymal stem cells (MSCs), the precise mechanisms determining the fate of stem cells are unclear [3]. This results in limited clinical translation of stem cell therapy. Moderate levels (100 μM) of NO donor can enhance the survival rate of MSCs via protection from renal ischemic injury after kidney damage [8] These results highlight the importance of NO as a potential modulator of stem cell therapies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
