Human jaw bone marrow mesenchymal stem cells (h-JBMMSCs) are multipotent progenitor cells with osteogenic differentiation potential. The relationship between adiponectin (APN) and the metabolism of h-JBMMSCs has not been fully elucidated, and the underlying mechanism remains unclear. The aim of the study was to investigate the effect and mechanism of APN on h-JBMMSC metabolism. h-JBMMSCs were obtained from the primary culture of human jaw bones and treated with or without APN (1 µg/mL). Osteogenesis-related gene expression was evaluated by real-time polymerase chain reaction (PCR), alkaline phosphatase (ALP) activity assay, and enzyme-linked immunosorbent assay (ELISA). To further investigate the signaling pathway, mechanistic studies were performed using Western blotting, immunofluorescence, lentiviral transduction, and SB202190 (a specific p38 inhibitor). Alizarin Red staining showed that APN promoted h-JBMMSC osteogenesis. Real-time PCR, ALP assay, and ELISA showed that ALP, osteocalcin (OCN), osteopontin, and integrin-binding sialoprotein were up-regulated in APN-treated cells compared to untreated controls. Immunofluorescence revealed that adaptor protein containing a pleckstrin homology domain, phosphotyrosine domain, and leucine zipper motif (APPL1) translocated from the nucleus to the cytoplasm with APN treatment. Additionally, the phosphorylation of p38 mitogen-activated protein kinase (MAPK) increased over time with APN treatment. Moreover, knockdown of APPL1 or p38 MAPK inhibition blocked the expression of APN-induced calcification-related genes including ALP, Runt-related transcription factor 2 (RUNX2), and OCN. Furthermore, Alizarin Red staining of calcium nodes was not increased by the knockdown of APPL1 or p38 inhibition. Our data suggest that this regulation is mediated through the APPL1–p38 MAPK signaling pathway. These findings collectively provide evidence that APN induces the osteogenesis of h-JBMMSCs through APPL1-mediated p38 MAPK activation.

Adiponectin (APN) is known to promote the osteogenic differentiation of human jaw bone marrow mesenchymal stem cells (h‐JBMMSCs). However, the underlying mechanism has not been fully elucidated. Previously, we showed that APN could promote h‐JBMMSC osteogenesis via APPL1‐p38 by up‐regulating osteogenesis‐related genes. Here, we aimed to determine whether APN could promote h‐JBMMSC chemotaxis through CXCL1/CXCL8. The CCK‐8, wound healing and transwell assays were used to evaluate the proliferation, migration and chemotaxis of h‐JBMMSCs with or without APN treatment. Chemotaxis‐related genes were screened using RNA‐seq, and the results were validated using real‐time PCR and ELISA. We also performed Western blot using the AMPK inhibitor, WZ4003, and the p38 MAPK inhibitor, SB203580, to identify the signalling pathway involved. We found that APN could promote h‐JBMMSC chemotaxis in the co‐culture transwell system. CXCL1 and CXCL8 were screened and confirmed as the up‐regulated target genes. The APN‐induced CXCL1/8 up‐regulation to promote chemotaxis could be blocked by CXCR2 inhibitor SB225002. Western blot revealed that the phosphorylation of AMPK and p38 MAPK increased in a time‐dependent manner with APN treatment. Additionally, WZ4003 and SB203580 could suppress the APN‐induced overexpression of CXCL1 and CXCL8. The results of the transwell chemotaxis assay also supported the above results. Our data suggest that APN can promote h‐JBMMSC chemotaxis by up‐regulating CXCL1 and CXCL8.

Objective: Refractory infection is an important factor affecting the progression of medication-related osteonecrosis of the jaw (MRONJ) from clinical stage I to stage II/III. The aim of this study was to explore the distribution of bacteria and their association with the inflammatory pathway of stage II/III MRONJ. Materials and Methods: Nine specimens of fresh inflammation tissue, located next to the necrotic bone or sequestrum, were collected from MRONJ patients. Nine specimens from normal oral mucosa were collected from healthy patients. The 16S rRNA gene sequencing method was used to determine the distribution characteristics of the bacterial colony. The protein microarray analysis was used to detect the expression of inflammatory cytokines. Results: The average relative abundance of Bacteroidetes, Spirochaetes, Synergistetes, and Tenericutes was higher, while Proteobacteria and Actinobacteria were lower in the MRONJ group. Most pro-inflammatory cytokines were up-regulated in the MRONJ group; yet, only IFNγ, TNFα, and IL8 showed statistical differences (P < 0.05). Porphyromonas and Treponema were positively correlated with IL8, and Mogibacterium was positively correlated with IFNγ and TNFα. Conclusions: IL8/IFNγ/TNFα pro-inflammatory effect caused by Porphyromonas, Treponema, and Mogibacterium may be the leading cause of advancing MRONJ and thus may be used as a new target for infection control.

The aim of the present study was to examine the clinical significance of lymph node metastatic (LNM) foci in predicting the overall survival of oral squamous cell carcinoma (OSCC) patients with LNM. MMP-21 was screened based on the LNM animal model of OSCC. Then four proteins, matrix metalloproteinase (MMP)-2, MMP-21, vascular endothelial growth factor (VEGF)-C and VEGF receptor (VEGFR)-3 were examined by immunohistochemistry in 63 OSCC specimens, including the primary tumors (PTs) and the corresponding LNM foci. The expression levels between the PTs and LNM foci were compared by Wilcoxon paired test. Relationships between expression of the four proteins and patient overall survival were assessed by Kaplan-Meier based on the median of the labeling index. The Cox proportional hazards model was used to assess the relative hazard factors. MMP-21 and VEGF-C expression levels were higher in the LNM foci than levels in the PTs. Results showed that MMP-2 and VEGF-C expression levels in the PTs and MMP-2, MMP-21 and VEGF-C expression in the LNM foci correlated with the overall survival of the OSCC patients with lymphatic metastasis. MMP-21 expression level in the LNM foci was the most reliable predictor among all the tested factors. These results suggest that high MMP-21 expression in LNM foci can be used to predict survival in OSCC patients with LNM. Characteristics of LNM foci may be more reliable than PT characteristics in predicting the overall survival of OSCC patients with lymphatic metastasis.

A plastic and biodegradable bone substitute consists of poly (l-lactic-co-glycolic) acid and 30 wt % β-tricalcium phosphate has been previously fabricated, but its osteogenic capability required further improvement. We investigated the use of globular adiponectin (gAPN) as an anabolic agent for tissue-engineered bone using this scaffold. A qualitative analysis of the bone regeneration process was carried out using μCT and histological analysis 12 weeks after implantation. CBCT (Cone Beam Computed Tomography) superimposition was used to characterise the effect of the different treatments on bone formation. In this study, we also explored adiponectin’s (APN) influence on primary cultured human jaw bone marrow mesenchymal stem cells gene expressions involved in the osteogenesis. We found that composite scaffolds loaded with gAPN or bone morphogenetic protein 2 (BMP2) exhibited significantly increased bone formation and mineralisation following 12 weeks in the extraction sockets of beagle dogs, as well as enhanced expression of osteogenic markers. In vitro investigation revealed that APN also promoted osteoblast differentiation of primary cultured human jaw bone marrow mesenchymal stem cells (h-JBMMSCs), accompanied by increased activity of alkaline phosphatase, greater mineralisation, and production of the osteoblast-differentiated genes osteocalcin, bone sialoprotein and collagen type I, which was reversed by APPL1 siRNA. Therefore, the composite scaffold loaded with APN exhibited superior activity for guided bone regeneration compared with blank control or Bio-Oss® (a commercially available product). The composite scaffold with APN has significant potential for clinical applications in bone tissue engineering.