Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the proliferation and osteogenic differentiation of human PDL (hPDL) cells. Cultured hPDL cells were irradiated (660 nm) daily with doses of 0, 1, 2 or 4 J⋅cm(-2). Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase (ALP) activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Our data showed that LPLI at a dose of 2 J⋅cm(-2) significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J⋅cm(-2) showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate (cAMP) is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.
Adenine ; analogs & derivatives ; pharmacology ; Adenylyl Cyclase Inhibitors ; Alkaline Phosphatase ; analysis ; genetics ; radiation effects ; Anthraquinones ; Bone Morphogenetic Protein 2 ; genetics ; Calcium ; metabolism ; radiation effects ; Cell Culture Techniques ; Cell Differentiation ; radiation effects ; Cell Line ; Cell Proliferation ; radiation effects ; Coloring Agents ; Core Binding Factor Alpha 1 Subunit ; genetics ; Cyclic AMP ; antagonists & inhibitors ; radiation effects ; Gene Expression ; radiation effects ; Humans ; L-Lactate Dehydrogenase ; analysis ; Lasers, Semiconductor ; Low-Level Light Therapy ; instrumentation ; Osteocalcin ; genetics ; Osteogenesis ; genetics ; radiation effects ; Periodontal Ligament ; cytology ; radiation effects ; Radiation Dosage ; Real-Time Polymerase Chain Reaction ; Reverse Transcriptase Polymerase Chain Reaction ; Tetrazolium Salts ; Thiazoles

S-phase kinase-associated protein 2 (Skp2) belongs to the F-box protein family. It is a component of the SCF E3 ubiquitin ligase complex. Skp2 has been shown to regulate cellular proliferation by targeting several cell cycle-regulated proteins for ubiquitination and degradation, including cyclin-dependent kinase inhibitor p27. Skp2 has also been demonstrated to display an oncogenic function since its overexpression has been observed in many human cancers. This review discusses the recent discoveries on the novel roles of Skp2 in regulating cellular senescence, cancer progression, and metastasis, as well as the therapeutic potential of targeting Skp2 for human cancer treatment.
Animals ; Cell Movement ; Cellular Senescence ; Cyclopentanes ; pharmacology ; Disease Progression ; Drug Delivery Systems ; methods ; Gene Expression Regulation, Neoplastic ; Humans ; Neoplasms ; metabolism ; pathology ; therapy ; Pyrimidines ; pharmacology ; S-Phase Kinase-Associated Proteins ; antagonists & inhibitors ; metabolism ; physiology ; Ubiquitination