The effect of aging on the biological and immunological characteristics of periodontal ligament stem cells
Abstract Background: Periodontal ligament stem cells (PDLSCs) have many applications in the field of cytotherapy, tissue engineering, and regenerative medicine. However, the effect of age on the biological characteristics and immunoregulation of PDLSCs remains unclear.Methods: In this study, we compared PDLSCs isolated from young and elderly individuals. PDLSCs proliferation was analyzed by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) staining, and apoptosis level was detected by Annexin V-PE/7-ADD staining. PDLSCs osteogenic/adipogenic differentiation potentials were assessed by alkaline phosphatase (ALP), Alizarin Red, Oil Red O staining and related quantitative analysis. PDLSCs immunoregulatory capacity was determined by EdU and Annexin V-PE/7-ADD staining. To explore its underlying mechanism, microarray, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and western blot analyses were performed to detect differentially expressed genes and proteins in PDLSCs. Results: Our results demonstrated that with aging, the proliferation and osteogenic/adipogenic differentiation potential of PDLSCs decreased, whereas apoptosis of PDLSCs increased. Moreover, the immunosuppressive ability of PDLSCs decreased with aging. Compared with PDLSCs from young subjects, analysis of mRNA expression revealed an upregulation of CCND3 and RC3H2 , and a downregulation of Runx2, ALP, COL1A1, PPARγ2, CXCL12, FKBP1A, FKBP1B, NCSTN, P2RX7, PPP3CB, RIPK2, SLC11A1, and TP53 in those from elderly individuals. Furthermore, protein expression levels of Runx2, ALP, COL1A1, and PPARγ2 in the elderly group was decreased, whereas that of CCND3 increased. Conclusions: Taken together, aging influences biological and immunological characteristics of PDLSCs, and thus it is more appropriate to utilized PDLSCs from young individuals for tissue regeneration, post-aging treatment, and allotransplantation.