Abstract
Periodontitis is a complex dental condition that has a number of different etiologies. Lin-28 homolog A (LIN28A) has been previously reported to regulate inflammation, where its expression levels have been indicated to be lower in periodontal tissues following periodontitis. However, there is a lack of evidence to indicate the precise role of LIN28A in periodontitis. In the present study, LIN28A and Runt-related transcription factor 2 (RUNX2) expression were measured in human periodontal biopsy tissues using reverse transcription-quantitative PCR (RT-qPCR). RT-qPCR and western blot analyses were also used to measure LIN28A and RUNX2 expression in human periodontal ligament stem cells (hPDLSCs) following lipopolysaccharide (LPS) induction. Following construction of the LIN28A overexpression plasmid, the expression of LIN28A, RUNX2, osteopontin, osterix and osteocalcin were detected using RT-qPCR and western blotting. Additionally, RT-qPCR was used for the detection of proinflammatory biomarkers (IL-8, IL-1β and IL-6) and alkaline phosphatase (ALP) expression. Protein expression of intranuclear and cytoplasmic NF-κB p65 and NF-κB p65 phosphorylation were assessed using western blot analysis. The expression of antioxidant factors including SOD and GSH were determined using corresponding commercial assay kits. ALP and the mineralization capacity of hPDLSCs were detected by ALP activity assay and Alizarin red staining. The expression of LIN28A was found to be decreased in periodontal biopsy tissues from periodontitis patients compared with normal tissues and LPS-induced hPDLSCs compared with untreated hPDLSCs, which was positively correlated with RUNX2 expression. LIN28A overexpression was revealed to attenuate inflammatory damage and oxidative stress whilst improving ALP active damage, restoring RUNX2 expression and osteoblastic mineralization in LPS-induced hPDLSCs. In conclusion, the present study suggests that LIN28A serves a key role as a mediator of osteoblast differentiation and mineralization. In addition, LIN28A was able to alleviate inflammatory injury and oxidative stress in LPS-induced hPDLSCs.