Pulpitis in primary teeth, a condition caused by presence of bacteria, is highly prevalent worldwide. The use of biocompatibility materials with anti-inflammatory, anti-bacterial, and regenerative properties is critical for prognosis of this endodontic disease. This study aimed to identify expression of human β defensin 4 (HBD4) in stem cells derived from human exfoliated deciduous teeth (SHED) and characterize the effects of HBD4 on SHED. Quantitative polymerase chain reaction (qPCR) was used to detect HBD4 expression in SHED and the effect of HBD4 on inflammatory factors in lipopolysaccharide (LPS)-stimulated SHED. Affinity measurement was made by the Fortebio Octet System to explore the potential interaction between LPS and HBD4. Western blot analysis was used to explore the effect of HBD4 on mitogen-activated protein kinase (MAPK) pathway. Colony-forming unit methods and scanning electron microscopy were applied to study antimicrobial effect of HBD4 on Fusobacterium nucleatum and Porphyromonas gingivalis. Alkaline phosphatase staining, alizarin red staining, qPCR and western blot were taken to detect effects of HBD4 on osteoblast/odontoblast differentiation of SHED. RT2 Profiler PCR Array was used to explore the potential signaling pathways involved in the osteogenic/odontogenic differentiation. HBD4 was highly expressed in SHED stimulated by TNF-α and IL-1α. HBD4 could bind to LPS directly and down-regulate IL-1α, IL-1β, IL-6, TNF-α in LPS-stimulated SHED, thus the activation of MAPK pathway decreased. HBD4 was sensitive to P. gingivalis and enhanced osteoblast/odontoblast differentiation potential of SHED by modulating Notch pathway. HBD4 was highly expressed in SHED stimulated by proinflammatory cytokines, and possessed anti-inflammatory, anti-bacterial activity. HBD4 promoted osteogenic/odontogenic differentiation of SHED. HBD4 may thus represent a suitable agent for vital pulp therapy in future clinic application.

No abstract

Objective To evaluate the therapeutic potential of stem cells from human exfoliated deciduous teeth (SHED) for diabetic peripheral neuropathy. Methods The biological characteristics of SHED were identified by flow cytometric study and evaluation of differentiation potential. Using high-fat feeding, diabetes was induced in GK rats, and SHED were transplanted into the caudal veins of these rats. Immunohistochemical analysis was used to compare the capillary to muscle fiber ratio and intra-epidermal nerve fiber density between SHED- and saline-treated diabetic rats. Further, the expressions of angiogenesis-related and neurotrophic factors were quantified by real-time PCR and western blot. Results SHED had a capacity of multiple differentiation and shared typical characteristics of mesenchymal stem cells. SHED transplantation relieved diabetic neuropathic pain, enabled functional recovery of the peripheral nerves, and increased the capillary to muscle fiber ratio and intra-epidermal nerve fiber density compared to the saline group and normal controls. Real-time PCR results showed that the expressions of CD31, vWF, bFGF, NGF, and NT-3 in the skeletal muscles were higher in the SHED group than in the saline groups. Western blot results indicated that the levels of the CD31 and NGF proteins were higher in the SHED transplantation group than the saline group. Conclusion SHED transplantation ameliorated diabetic peripheral neuropathy in diabetic GK rats. Thus, systemic application of SHED could be a novel strategy for the treatment of diabetic peripheral neuropathy.

Background Treatments based on stem cell-derived small extracellular vesicles (sEVs) have been explored as an alternative to stem cell transplantation-based therapies in periodontal regeneration. Dental follicle stem cells (DFSCs) have shown great potential for regenerative medicine applications. However, it is unclear whether sEVs derived from DFSCs (DFSCs-sEVs) could be used in periodontal regeneration. This study investigates whether DFSCs-sEVs could regenerate damaged periodontal tissue and the potential underlying mechanism. Methods DFSCs-sEVs were isolated and identified, and periodontal ligament stem cells (PDLSCs) were cocultured with the isolated sEVs. The effect of DFSCs-sEVs on the biological behaviour of PDLSCs was examined using EdU assay, CCK-8 assay, cell cycle analysis, wound healing, alizarin red staining, qRT-PCR, and western blot analysis. RNA sequencing and functional enrichment analysis were used to detect the signal pathway involved in the effect of DFSCs-sEVs on PDLSCs. PDLSCs were pretreated with ERK1/2 or p38 MAPK inhibitors to investigate the possible involvement of the ERK1/2 and p38 MAPK pathways. Additionally, DFSCs-sEVs were combined with collagen sponges and transplanted into the periodontal defects in SD rats, and then, pathological changes in periodontal tissue were examined using haematoxylin and eosin (HE) staining and micro-CT. Results PDLSCs could internalize DFSCs-sEVs, thereby enhancing the proliferation assessed using EdU assay, CCK-8 assay and cell cycle analysis. DFSCs-sEVs significantly enhanced the migration of PDLSCs. DFSCs-sEVs promoted osteogenic differentiation of PDLSCs, showing deep Alizarin red staining, upregulated osteogenic genes (RUNX2, BSP, COL1), and upregulated protein expression (RUNX2, BSP, COL1, ALP). We found that p38 MAPK signalling was activated via phosphorylation. Inhibition of this signalling pathway with a specific inhibitor (SB202190) partially weakened the enhanced proliferation. After DFSCs-sEVs transplantation, new periodontal ligament-like structures and bone formation were observed in the damaged periodontal area in rats. Labelled DFSCs-sEVs were observed in the newly formed periodontal ligament and soft tissue of the defect area. Conclusions Our study demonstrated that DFSCs-sEVs promoted periodontal tissue regeneration by promoting the proliferation, migration, and osteogenic differentiation of PDLSCs. The effect of DFSCs-sEVs in promoting PDLSCs proliferation may be partially attributed to the activation of p38 MAPK signalling pathway. DFSCs-sEVs provide us with a novel strategy for periodontal regeneration in the future.