Exosomal miR-205-5p derived from periodontal ligament stem cells attenuates the inflammation of chronic periodontitis via targeting XBP1.

INTRODUCTION: Chronic periodontitis (CP) is an inflammatory periodontal disease with high incidence and complex pathology. This research is aimed to investigate the function of exosomal miR-205-5p (Exo-miR-205-5p) in CP and the underlying molecular mechanisms. METHOD: Exo-miR-205-5p was isolated from miR-205-5p mimics-transfected periodontal ligament stem cells (PDLSCs), and subsequently cocultured with lipopolysaccharide (LPS)-induced cells or injected into LPS-treated rats. The mRNA expression of inflammatory factors and Th17/Treg-related factors were measured by quantitative real-time PCR. The contents of inflammatory factors and the percentages of Th17/Treg cells were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively. Besides, the target relation between miR-205-5p and X-box binding protein 1 (XBP1) was explored. RESULTS: MiR-205-5p was downregulated in LPS-induced PDLSCs and corresponding exosomes. Exo-miR-205-5p inhibited inflammatory cell infiltration, decreased the production of TNF-α, IL-1ß, and IL-6, and decreased the percentage of Th17 cells in LPS-treated rats. In addition, XBP1 was a target of miR-205-5p. Overexpression of XBP1 weakened the effects of Exo-miR-205-5p on inhibiting inflammation and regulating Treg/Th17 balance in LPS-induced cells. CONCLUSIONS: Exo-miR-205-5p derived from PDLSCs relieves the inflammation and balances the Th17/Treg cells in CP through targeting XBP1.

Corrigendum: Injecting Immunosuppressive M2 Macrophages Alleviates the Symptoms of Periodontitis in Mice.

[This corrects the article DOI: 10.3389/fmolb.2020.603817.].

Injecting Immunosuppressive M2 Macrophages Alleviates the Symptoms of Periodontitis in Mice.

Periodontitis is the second most common oral disease affecting tooth-supporting structures. The tissue damage is mainly initiated by the excessive secretion of proinflammatory cytokines by immune cells. Macrophages are a type of antigen-presenting cells that influence the adaptive immunity function. We used a unique set of cytokines, i.e., a combination of IL-4, IL-13, and IL-10, to stimulate macrophages into a subset of M2 polarization cells that express much higher levels of ARG-1, CD206, and PDL-2 genes. The cells' anti-inflammatory potential was tested with mixed-lymphocyte reaction assay, which showed that this subset of macrophages could increase IL-2 secretion and suppress IL-17, IL-6, and TNF-α secretion by splenocytes. The gram-negative bacterial species Porphyromonas gingivalis was used to initiate an inflammatory process in murine periodontal tissues. In the meantime, cell injection therapy was used to dampen the excessive immune reaction and suppress osteoclast differentiation during periodontitis. Maxilla was collected and analyzed for osteoclast formation. The results indicated that mice in the cell injection group exhibited less osteoclast activity within the periodontal ligament region than in the periodontitis group. Moreover, the injection of M2 macrophages sustained the regulatory population ratio. Therefore, the M2 macrophages induced under the stimulation of IL-4, IL-13, and IL-10 combined had tremendous immune modulation ability. Injecting these cells into local periodontal tissue could effectively alleviate the symptom of periodontitis.

IL-10 secreting B cells regulate periodontal immune response during periodontitis.

Periodontitis is a disease caused by periodontopathogens and is characterized by periodontal inflammation and alveolar bone resorption. As has been proven, host immune responses incite the development and progression of periodontitis. The present study sought to establish B10 cell functions and mechanisms in regulating host immunity during periodontitis. Periodontopathogen-specific B10 cells were purified and then injected into recipients to create the adoptive transfer models. We compared inflammatory cytokines and regulatory T (Treg)/Th17 cell expression in a healthy, normal model, an experimental periodontitis model, and experimental periodontitis model adoptively transferred with B10 cells. Compared with experimental periodontitis animals, our results showed that transfer of B10 cells alleviated alveolar bone resorption (P < 0.05) by reducing periodontal osteoclastogenesis (P < 0.05). Additionally, we found that B10 cell transfer into the experimental periodontitis ones resulted in increased IL-10 (P < 0.05), but decreased IL-17 (P < 0.05) and receptor activator for nuclear factor κB ligand (RANKL) (P < 0.05) gene and protein expression in local lesions. Moreover, adoptive transfer of B10 cells reduced the proportion of Th17 cells (P < 0.05) in the gingiva. The results of our study confirmed that B10 cells can modulate local host immune responses and prevent inflammatory damage of alveolar bone by reducing pro-inflammatory cytokine expression and decreasing local proliferation of Th17 cells.

Improved RANKL expression and osteoclastogenesis induction of CD27+CD38- memory B cells: A link between B cells and alveolar bone damage in periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a bacteria-induced disease that often leads to alveolar bone damage. Its mechanisms were considered to be complicated, involving an imbalance of the formation and resorption of bone. We sought to disclose the antibody-independent function of B cells during periodontitis. MATERIAL AND METHODS: Production of receptor activator for nuclear factor-κB ligand (RANKL) by total lymphocytes or sorted B-cell subsets in gingiva from healthy or experimental periodontitis animals was examined by flow cytometry, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay. To define the effects of lymphocytes or B-cell subsets on osteoclastogenesis induction, bone marrow mononuclear cells were culture in culture medium of lymphocytes or cocultured with B-cell subsets. Osteoclasts were enumerated by tartrate-resistant acid phosphatase staining. Constituent ratio of B-cell subsets in healthy or experimental periodontitis was also detected by flow cytometry. RESULT: Gingiva B cells produce more RANKL and support more osteoclastogenesis than T and other lymphocytes, and this potential improved in periodontitis. Memory B cells (CD27+CD38-) decreased their percentage in periodontitis. Memory B cells have the highest propensity for RANKL production. Remarkably, memory B cells from periodontitis animals expressed significantly more RANKL compared to healthy controls. Memory B cells supported osteoclast differentiation in vitro in a RANKL-dependent manner, and the number of osteoclasts was higher in cultures with memory B cells from periodontitis animals than in those derived from healthy ones. Other B-cell subsets have limited impact on osteoclast formation. CONCLUSION: Findings of this study further disclose the roles of B cells engaged in periodontal immunomodulation and reveal the considerable importance of memory B cells in alveolar bone homeostasis and their likely contribution to alveolar bone destruction in periodontitis.

Switched memory B cells promote alveolar bone damage during periodontitis: An adoptive transfer experiment.

Periodontitis is a bacteria-induced disease that often leads to alveolar bone damage. We sought to determine the role and mechanism of switched memory B cells in alveolar bone destruction during periodontitis. Sensitized B cells were sorted and cultured, then their expression of receptor activator for nuclear factor-κB ligand (RANKL), interleukin-6 (IL-6), and interleukin-12 (IL-12) was detected. Using these cells, we prepared adoptive transfer models in which we induced periodontitis. We found that switched memory B cells produced more RANKL in terms of both protein and mRNA levels than other subpopulations. Switched memory B cells expressed more IL-6 and IL-12 mRNA than other subpopulations, but differences in respective protein levels were not significant. Moreover, we found that switched memory B cell transfer resulted in increased alveolar bone loss and periodontal osteoclastogenesis. Moreover, switched memory B cell transfer increased the proportion of Th1 and Th17 cells as well as the expression of RANKL, osteoprotegerin (OPG), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-1ß, IL-6, IL-17A in gingiva, and cervical lymph nodes (CLNs). The outcomes of the present study indicate that switched memory B cells regulate alveolar bone homeostasis via enhancing cytokine expression and increasing proliferation of Th1 and Th17 cells.

[Mechanism of lipolytic and smooth effects of D980-nm laser treatment on skin tissue in rats].

Objective: To determine the efficacy of D980-nm laser in dissolving fat and renewing skin, and to explore the clinical application of D980-nm laser in reconstruction of photodamaged skin. Methods: Eighteen 12-14 month-old male Sprague-Dawley rats, weighing 400-450 g, were randomly divided into 3 groups ( n=6). The rat skin at the left side was exposed to D980-nm laser irradiation at a density of 20 J/cm 2, a power of 8 W, a pulse width of 20 ms, and a pulse frequency of 40 Hz for 1 time (group A), 2 times of 5-minute interval (group B), and 3 times of 5-minute interval (group C) as a treatment course, for 4 treatment courses with an interval of 1 week; the other side of the skin was not treated as the control groups (groups A1, B1, and C1, respectively). After 8 weeks, the skin was harvested for HE staining and immunohistochemical staining to observe the structure changes of skin, to measure the dermal thickness, to count the number of fibroblasts, and detect the expressions of transforming growth factor ß 1 (TGF-ß 1) and basic fibroblast growth factor (bFGF). Results: Compared with groups A1, B1, and C1, the skin structure was significantly improved in groups A, B, and C. After D980-nm laser irradiation, the number of fat cells decreased; local angiogenesis was observed; the total number of fibroblasts and fibers increased; the collagen fiber had large diameter, and arranged closely and regularly; the dermal thickness and the number of the fibroblasts increased; and the expressions of TGF-ß 1 and bFGF were significantly enhanced, showing significant differences ( P<0.05). With increased D980-nm laser irradiation times, the above indexes increased, showing significant differences between group C and groups A, B ( P<0.05). Conclusion: D980-nm laser treatment has lipolytic and tender effect on the skin, and the frequency of the treatment is an important factor in skin renewal.