Fbs α mem

All experiments were performed with the approval of the Ethics Committee of Stomatology College of Fourth Military Medical University (FMMU), and each participants sign a written content (Approval Number: 2016051). Healthy teeth of 18–25 year old orthodontic patients were extracted (n = 3) at the Department of Maxillofacial Surgery, Qindu Stomatology Hospital, Xian, China. All the cells used in this study were at passages 2–4. PDLSCs were isolated and cultured as described preciously [6 (link), 7 (link)]. Briefly, periodontal ligament (PDL) was carefully scraped and digested in 3mg/ml collagenase type I (Worthington Biochem) for 15 min at 37°C with 5% CO₂, Single-cell suspensions were obtained by passing the cells through a 70μm strainer (BD Labware) and then was cultured at 37°C in 5% CO₂ using 10% fetal bovine serum (FBS) α-MEM (Invitrogen) supplemented with penicillin/streptomycin (Invitrogen). Cell culture medium was changed every three days. 1×10⁶ PDLSCs were harvested. Then the single-cell suspension was re-suspended and stained with mesenchymal stem cell surface markers, including Stro-1 (PE), CD146 (PE), CD34 (PE) and CD45 (APC) (e Bioscience) at 4°C and identified with flow cytomerty (Beckman Coulter, Fullerton, CA, USA). The experiment was repeated 3 times.

Human nasopharyngeal epithelial Detroit 562 cells (American Type Culture Collection, Manassas, VA, USA), bronchial epithelial Calu-3 cells (American Type Culture Collection), and cervical epithelial HeLa cells (RIKEN Bioresource Center) were cultured in Eagle’s minimum essential medium alpha (α-MEM; Invitrogen, Carlsbad, CA, USA) supplemented with 10% fetal bovine serum (FBS) (Invitrogen) (10% FBS α-MEM), penicillin (100 U/ml), and streptomycin (100 µg/ml) at 37°C in a 5% CO₂ atmosphere.