Superoxide dismutase 2 scavenges ROS to promote osteogenic differentiation of human periodontal ligament stem cells by regulating Smad3 in alveolar bone‐defective rats

Abstract

BackgroundOsteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) is an essential event in alveolar bone regeneration. Oxidative stress may be the main inhibiting factor of hPDLSC osteogenesis. Superoxide dismutase 2 (SOD2) is a key antioxidant enzyme, but its effect on hPDLSC osteogenic differentiation is unclear.MethodsSeveral surface markers were detected by flow cytometry, and the differentiation potential of hPDLSCs was validated by alkaline phosphatase (ALP), Alizarin Red S, and Oil Red O staining. Osteogenic indicators of hPDLSCs were detected by real‐time quantitative polymerase chain reaction (RT‐qPCR), Western blotting, and ALP staining. Furthermore, alveolar bone defect rat models were analyzed through micro‐CT, hematoxylin and eosin, and Masson staining. The intracellular reactive oxygen species (ROS) level was evaluated by a ROS assay kit. Finally, the expression of SOD2, Smad3, and p‐Smad3 in hPDLSCs was detected by RT‐qPCR and Western blotting (WB).ResultsSOD2 positively regulated the gene and protein expressions of ALP, BMP6, and RUNX2 in hPDLSCs (p < 0.05). Ideal bone formation and continuous cortical bone were obtained by transplanting LV‐SOD2 hPDLSCs (lentivirus vector for overexpressing SOD2 in hPDLSCs) in vivo. Exogenous H2O2 downregulated osteogenic indicators (ALP, BMP6, RUNX2) in hPDLSCs (p < 0.05); this was reversed by overexpression of SOD2. WB results showed that the Smad3 and p‐Smad3 signaling pathways participated in the osteogenic process of SOD2 in hPDLSCs.ConclusionSOD2 positively regulated hPDLSC osteogenic differentiation in vitro and in vivo. Mechanistically, SOD2 promotes hPDLSC osteogenic differentiation by regulating the phosphorylation of Smad3 to scavenge ROS. This work provides a theoretical basis for the treatment of alveolar bone regeneration.

Loss of Slc39a12 in hippocampal neurons is responsible for anxiety-like behavior caused by temporomandibular joint osteoarthritis

“…Nox4 is a member of NADPH oxidase family, widely expressed in all brain regions, functioning as a major source of endogenous ROS production [ 36 ]. As one of the major antioxidant enzymes that scavenge ROS, SOD2 plays an important role in protecting cells from oxygen-free radical poisoning [ 37 ]. Compared with the NC group, the reduced GSH content in hippocampus of the MIA group decreased, the MDA content increased, Nox4 expression increased, and SOD2 expression decreased, suggesting that TMJ-OA may induce increased oxidative stress levels.…”

The Genetic Aspects of Periodontitis Pathogenesis and the Regenerative Properties of Stem Cells

“…For instance, the overexpression of superoxide dismutase 2 in PDLSCs stimulated the expression of osteogenic markers. Importantly, the use of transfected cells was associated with a greater bone volume in rats with alveolar bone defects [169].…”

“…The generation of reactive oxygen species (ROS) is correlated with both physiological and pathological properties, as these molecules can kill microorganisms as well as host cells [167]. Scavenging ROS using antioxidant agents or platforms could enhance the osteogenic features of PDLSCs [168,169]. For instance, the overexpression of superoxide dismutase 2 in PDLSCs stimulated the expression of osteogenic markers.…”