Osteoclastogenesis in periodontal diseases: Possible mediators and mechanisms

BackgroundPeriodontitis is the inflammation of the tooth-supporting structures and is one of the most common diseases of the oral cavity. The outcome of periodontal infections is tooth loss due to a lack of alveolar bone support. Osteoclasts are giant, multi-nucleated, and bone-resorbing cells that are central for many osteolytic diseases, including periodontitis. Receptor activator of nuclear factor-kB ligand (RANKL) is the principal factor involved in osteoclast differentiation, activation, and survival. However, under pathological conditions, a variety of pro-inflammatory cytokines secreted by activated immune cells also contribute to osteoclast differentiation and activity. Lipopolysaccharide (LPS) is a vital component of the outer membrane of the Gram-negative bacteria. It binds to the Toll-like receptors (TLRs) expressed in many cells and elicits an immune response.HighlightsThe presence of bacterial LPS in the periodontal area stimulates the secretion of RANKL as well as other inflammatory mediators, activating the process of osteoclastogenesis. RANKL, either independently or synergistically with LPS, can regulate osteoclastogenesis, while LPS alone cannot. MicroRNA, IL-22, M1/M2 macrophages, and memory B cells have recently been shown to modulate osteoclastogenesis in periodontal diseases.ConclusionIn this review, we summarize the mechanism of osteoclastogenesis accompanying periodontal diseases at the cellular level. We discuss a) the effects of LPS/TLR signaling and other cytokines on RANKL-dependent and -independent mechanisms involved in osteoclastogenesis; b) the recently identified role of several endogenous factors such as miRNA, IL-22, M1/M2 macrophages, and memory B cells in regulating osteoclastogenesis during periodontal pathogenesis.     

COPD患者血清 Cav-1及 CXCL12水平检测与并发肺动脉高压的相关性研究

目的　探讨血清小窝蛋白 -1(caveolave-1,Cav-1)及趋化因子 C-X-C基元配体 12(chemokine C-X-C ligand 12,CXCL12)水平与慢性阻塞性肺疾病 (chronic obstructive pulmonary disease,COPD)并发肺动脉高压 (pulmonary hypertension,PH)的相关性。方法　收集 2019年 3月～ 2020年 3月期间在咸阳市第一人民医院和商洛市中心医院就诊的 115例 COPD 患者作为研究对象 ,依据患者是否并发 PH分为非 PH组 (NPH组 ,70例 )和 PH组 (45例 )。另选取 43例同期体检健康者作为对照组,采用酶联免疫吸附法测定血清 Cav-1和 CXCL12水平,所有患者均接受肺功能检测 ,用肺功能检测仪检测患者治疗前的 1s 用力呼气容积占预计值的百分比 (forced expiratory volume/predicted value,FEV1/Pre), FEV1占用力肺活量 (Forced vital capacity,FVC)的百分比 (FEV1/FVC)。通过彩色多普勒超声检查获得所有 COPD患者的肺动脉收缩压 (pulmonary artery systolic pressure,PASP)。收集患者的临床资料 ,包括二氧化碳分压 (PCO2)、氧分压 (PO2)、B型脑利钠肽 (brain natriuretic peptide,BNP)以及白介素 -6(interleukin- 6,IL-6)等,比较分析以上指标的变化与 COPD并发 PH的相关性。结果　在对照组 ,NPH组和 PH组中 ,血清 Cav-1和 CXCL12水平分别为 10.37±2.28,7.23±1 .72,4.81±0.90μg/L和 65.74±12.27, 175.36±26.19, 270.33±43.79pg/ml,与对照组比较 ,NPH组和 PH组的 CXCL12水平明显增高 ,且 PH组增高更显著 ;与对照组比较 ,NPH组和 PH组的 Cav-1水平则明显降低 ,且 PH组降低更显著,差异均有统计学意义 (F=103.71～ 130.67,均 P=0.000)。相关性分析显示 ,NPH组和 PH组的血清 Cav-1及 CXCL12水平分别呈负相关性 (r=-0.813,-0.827, 均 P <0.01),NPH组的 CXCL12水平分别与 PCO2,PASP,IL-6及 BNP水平呈正相关性 ,而与 FEV1/Pre,FEV1/FVC及 PO2呈负相关性。 NPH组的 Cav-1分别与 PCO2,PASP,IL-6及 BNP水平呈负相关性 ,而与 FEV1/Pre,FEV1/FVC及 PO2呈正相关性（ rCXCL12=0.845,0.810,0.807,0.783,-0.799,-0.775和 -0.793,均 P<0.01;rCav-1=-0.853,-0.828,-0.816,-0.792,0.763,0.803,0.822,均 P <0.01）。PH组的 CXCL12水平分别与 PCO2,PASP,IL-6及 BNP水平呈正相关性 ,而与 FEV1/Pre,FEV1/FVC及 PO2呈负相关性。 PH组的 Cav-1水平分别与 PCO2,PASP,IL-6及 BNP水平呈负相关性,而与 FEV1/Pre,FEV1/FVC及 PO2呈正相关性（ rCXCL12=0.839,0.816, 0.817,0.806,-0.782,-0.785,-0.809,均 P<0.01;rCav-1=-0.862,-0.821,-0.819,-0.797,0.782,0.811,0.829,均 P <0.01）。结论　血清 Cav-1及 CXCL12水平的差异性变化可能与 COPD患者 PH的形成有关,调节 Cav-1及 CXCL12水平能抑制炎症因子释放 ,缓解 COPD病情进展 ,改善患者的临床症状。     

Intracellular Fas ligand is elevated in T lymphocytes in severe aplastic anaemia

Increased expression of Fas receptor by haemopoietic progenitors in aplastic anaemia (AA) suggests that excessive apoptosis contributes to multilineage bone marrow (BM) failure. To investigate the role of Fas ligand (FasL) in triggering progenitor cell death, we examined FasL levels in T lymphocytes of patients with severe untreated AA (n = 8). Expression of FasL on the surface of CD3+ cells was not detectable. However, flow cytometric analysis of saponin-permeabilized cells demonstrated higher levels of intracellular FasL in AA than in normal T cells (P < 0.005), both prior to and following activation with phytohaemagglutinin. Confocal microscopy revealed that FasL-specific signals overlapped with cathepsin D staining, indicating that intracellular FasL is stored in lysosomal granules. Levels of intracellular FasL in patients examined 1 month after immunosuppression with antilymphocyte globulin and cyclosporin A were lower than prior to treatment. The caspase inhibitors, DEVD and zVAD, enhanced colony formation and prolonged survival of AA BM cells in liquid cultures by about 10-fold (P < 0.05). Taken together, these data provide further evidence that apoptosis by the Fas/FasL system plays a role in the depletion of stem cells in AA.     

In situ expression of Granzyme B and Fas‐ligand in the liver of viral hepatitis

Abstract: Background/Aims: The molecular mechanism involved in hepatocellular injury in viral hepatitis remains to be clarified. Methods: We investigated the in situ expression of effector molecules of cytotoxic T lymphocytes such as Fas‐ligand (Fas‐L), perforin and Granzyme B (Gr‐B) immunohistochemically in liver tissues from 20 patients with chronic hepatitis B (CHB) and C (CHC). The degree of cell infiltration was analysed semi‐quantitatively and compared with the histological activity index (HAI). Fas‐L was expressed in both CD4 and CD8 T‐cells in the portal tract as well as in the parenchyma. Results: Immunostaining of serial sections demonstrated that mononuclear cells at interface hepatitis and focal necrosis were mainly Fas‐L positive CD8 T‐cells. On the other hand, the expression of perforin or Gr‐B was limited to a few mononuclear cells in the portal tract and parenchyma. Semi‐quantitative analysis showed a positive correlation between HAI and the grade of infiltration of CD8 T‐cells or Fas‐L‐positive cells, while the correlation was not apparent between HAI and the number of Gr‐B positive cells. The expression of these molecules was not different between types of viruses. Conclusions: These results suggest that Fas‐L‐positive CD8 T‐cells play a major role in the pathogenesis of liver cell injury in chronic hepatitis.     

Integrated nanotechnology platform for tumor-targeted multimodal imaging and therapeutic cargo release

A major challenge of targeted molecular imaging and drug delivery in cancer is establishing a functional combination of ligand-directed cargo with a triggered release system. Here we develop a hydrogel-based nanotechnology platform that integrates tumor targeting, photon-to-heat conversion, and triggered drug delivery within a single nanostructure to enable multimodal imaging and controlled release of therapeutic cargo. In proof-of-concept experiments, we show a broad range of ligand peptide-based applications with phage particles, heat-sensitive liposomes, or mesoporous silica nanoparticles that self-assemble into a hydrogel for tumor-targeted drug delivery. Because nanoparticles pack densely within the nanocarrier, their surface plasmon resonance shifts to near-infrared, thereby enabling a laser-mediated photothermal mechanism of cargo release. We demonstrate both noninvasive imaging and targeted drug delivery in preclinical mouse models of breast and prostate cancer. Finally, we applied mathematical modeling to predict and confirm tumor targeting and drug delivery. These results are meaningful steps toward the design and initial translation of an enabling nanotechnology platform with potential for broad clinical applications.A long-term goal in contemporary cancer nanomedicine has been to design and generate drug delivery systems that improve the narrow therapeutic window associated with conventional chemotherapeutics (1, 2). Conceptually, several nanotechnology-based entity candidates, including protocells (3), biosynthetic nanoparticles (NPs), viruses, and liposome-based nanoparticles, could be targeted for active delivery through a defined cell surface ligand receptor system and/or physically triggered for finely tuned cargo release (2, 4, 5).Numerous efforts have been made to functionalize NPs by combining them with antibodies, aptamers, peptides, vitamins, or carbohydrates (6–8), but the majority of studies involve untargeted nanoplatforms (4, 9). In practice, targeting NPs is far from trivial, and ongoing challenges include synthesis and purification, selection of an appropriate ligand receptor, and specific composition for NP conjugation. Even the conjugation reaction itself may alter the binding of the tumor-targeting moiety to its receptor through conformational changes, steric freedom restriction, or orientation distortion (10, 11). Unfortunately, the cost-to-benefit ratio of these modifications often elevate the complexity of the NP synthesis, complicating regulatory hurdles because of formulations that are heterogeneous or difficult to reproduce (10, 12, 13).To minimize such drawbacks, NPs can be functionalized via virus-based nanoplatforms as an alternative for targeted cargo delivery (14–16). In particular, filamentous bacteriophage (phage)—a prokaryotic virus—is an attractive candidate to develop a bionanomedicine for cancer therapeutics because phage particles are cost-effectively produced with biological uniformity, as well as being physically robust and stable under harsh conditions (17). Notably, phage-based nanoplatforms are biocompatible and nonpathogenic with eukaryotic organisms and are able to preserve the desired cell targeting and internalization (18). Moreover, phage particles are ideal for incorporating other NPs, which can be released after reaching the tumor site. An admixture of colloidal gold NP (AuNP) with phage particles spontaneously organizes into hydrogel network-like fractal structures (19, 20). These hydrogel networks offer convenient multifunctional integration within a single entity for tumor targeting, enhanced fluorescence and dark-field microscopy, near-infrared (NIR) photon-to-heat conversion, and surface-enhanced Raman scattering (SERS)-based detection (20, 21).In the present work, we developed a tumor targeting theranostic (meaning a combination of therapeutics and diagnostics) hydrogel-based nanoplatform that enables ligand-directed tumor targeting, multimodal imaging capability, and triggered therapeutic cargo release. Our data suggest that targeted hydrogel photothermal therapy represents a functional theranostic approach (fostering “see and treat, treat and see”) in the diagnosis and management of tumors.     

Analysis of serum soluble CD40 ligand (sCD40L) in the patients undergoing allogeneic stem cell transplantation: platelet is a major source of serum sCD40L

CD40 ligand (CD40L) is expressed not only on activated T cells but also on activated platelets. A soluble CD40 ligand (sCD40L) is released from the activated T cells and platelets by ill-defined proteolytic process in vitro. It has been reported that sCD40L is elevated in the serum of patients with systemic lupus erythematosus, unstable angina, essential thrombocythemia, and autoimmune thrombocytopenic purupura. However, source of sCD40L in vivo remains to be elucidated. We investigated the serial sCD40L in the serum in patients undergoing allogeneic stem cell transplantation and compared with the platelets number and soluble IL2R, which is a marker of activated T cells. The value of sCD40L was well correlated with platelet number or thrombopoiesis. In cases of severe graft vs. host disease with markedly increased sIL2R, sCD40L was not increased in vivo. These results indicate that sCD40L in vivo is released mainly from the platelets or in the process of platelet production but not from the activated T cells.     

Effect of sumac extract on serum oxidative status,RANKL/OPG system and alveolar bone loss in experimental periodontitis in rats

Objectives

Sumac (Rhus coriaria L.) is widely used spice which has several properties such as antioxidant, anti-inflammatory and antimicrobial. The purpose of this animal study was to evaluate the effects of sumac extract on levels of receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG) expression, serum oxidative status, and alveolar bone loss in experimental periodontitis.

Material and Methods

Twenty-four Wistar rats were separated into three groups: non-ligated (NL, n=8), ligature only (LO, n=8), and ligature and treated with sumac extract (S, n=8) (20 mg/kg per day for 11 days). A 4/0 silk suture was placed around the mandibular right first molars subgingivally; after 11 days, the rats were sacrificed, and alveolar bone loss was histometrically measured. The detection of RANKL and OPG were immunohistochemically performed. Levels of serum total antioxidant status (TAS)/total oxidant status (TOS), and oxidative stress index (OSI) were also analyzed.

Results

Alveolar bone loss was significantly greater in the LO group compared to the S and NL groups (p<0.05). The number of inflammatory cell infiltrate (ICI) and osteoclasts in the LO group was significantly higher than that of the NL and S groups (p<0.05). The number of osteoblasts in the LO and S groups was significantly higher than that of the NL group (p<0.05). There were significantly more RANKL-positive cells in the LO group than in the S and NL groups (p<0.05). OPG-positive cells were higher in S group than in LO and NL groups (p<0.05). TOS and OSI levels were significantly reduced in S group compared to LO group (P<0.05) and TAS levels were similar in S and NL group (p>0.05).

Conclusions

The present study showed that systemic administration of sumac extract may reduce alveolar bone loss by affecting RANKL/OPG balance, TOS and OSI levels in periodontal disease in rats.