An acute injection of Porphyromonas gingivalis lipopolysaccharide modulates the OPG/RANKL system and interleukin-6 in an ovariectomized mouse model

Background/aims:  In the present study, we attempted to develop a simulated model to explore the causal effects of periodontal pathogens on skeletal homeostasis in postmenopausal osteoporosis.
Methods:  Fifty-three female adult ICR mice were randomly assigned to an experimental group (ovariectomized) or a control group. A single injection of Porphyromonas gingivalis lipopolysaccharide ( P. gingivalis -LPS, ATCC 33277) or Escherichia coli lipopolysaccharide ( E. coli -LPS) was administered intraperitoneally 4 weeks after an ovariectomy. Concentrations of interleukin-6 (IL-6), osteoprotegerin (OPG), and the receptor activator of nuclear factor-κB ligand (RANKL) in serum were subsequently analyzed using an enzyme-linked immunosorbent assay (ELISA).
Results:  Under stimulation with P. gingivalis -LPS or E. coli -LPS, the concentration of OPG rose in both groups. The serum level of RANKL showed a decreasing trend 24 h after the injection in both groups. After injection of P. gingivalis -LPS in both the experimental and control animals, the OPG : RANKL ratio increased 24 h after the booster (22.26–620.99, P  < 0.05). The serum level of IL-6 in the experimental group significantly increased 1–6 h after administration of E. coli -LPS and 1–3 h after administration of P. gingivalis -LPS ( P  < 0.05).
Conclusions:  A single booster injection of P. gingivalis -LPS induced short-term changes in OPG, RANKL, and IL-6 serum levels in this ovariectomized mouse model.     

An acute injection of Porphyromonas gingivalis lipopolysaccharide modulates the OPG/RANKL system and interleukin‐6 in an ovariectomized mouse model

Background/aims: In the present study, we attempted to develop a simulated model to explore the causal effects of periodontal pathogens on skeletal homeostasis in postmenopausal osteoporosis. Methods: Fifty‐three female adult ICR mice were randomly assigned to an experimental group (ovariectomized) or a control group. A single injection of Porphyromonas gingivalis lipopolysaccharide (P. gingivalis‐LPS, ATCC 33277) or Escherichia coli lipopolysaccharide (E. coli‐LPS) was administered intraperitoneally 4 weeks after an ovariectomy. Concentrations of interleukin‐6 (IL‐6), osteoprotegerin (OPG), and the receptor activator of nuclear factor‐κB ligand (RANKL) in serum were subsequently analyzed using an enzyme‐linked immunosorbent assay (ELISA). Results: Under stimulation with P. gingivalis‐LPS or E. coli‐LPS, the concentration of OPG rose in both groups. The serum level of RANKL showed a decreasing trend 24 h after the injection in both groups. After injection of P. gingivalis‐LPS in both the experimental and control animals, the OPG : RANKL ratio increased 24 h after the booster (22.26–620.99, P < 0.05). The serum level of IL‐6 in the experimental group significantly increased 1–6 h after administration of E. coli‐LPS and 1–3 h after administration of P. gingivalis‐LPS (P < 0.05). Conclusions: A single booster injection of P. gingivalis‐LPS induced short‐term changes in OPG, RANKL, and IL‐6 serum levels in this ovariectomized mouse model.     

慢性牙周炎患者龈沟液OPG和RANKL的变化及意义

目的:探讨慢性牙周炎患者龈沟液中核因子-κB受体活化子配体(receptor activator for NF-κB ligand.RANKL)和骨保护素(osteoprotegerin,OPG)的变化及意义.方法:采用滤纸条法收集23例正常对照者和34例慢性牙周炎患者龈沟液(gingival crevicular fluid,GCF)标本,ELISA法测定上清液RANKL和OPG含量,利用Optimas 5.0图像分析软件对检测牙的根尖片进行灰度分析.结果:对照组和慢性牙周炎组临床指标(PD、AL、PLI和SBI)之间存在显著性统计学差异(P<0.01).2组GCF中RANKL、OPG和RANKL/OPG比值之间存在显著性统计学差异(P<0.01).慢性牙周炎组GCF中OPG浓度与PD和AL之间存在负相关关系(分别为P<0.01和P<0.05),RANKL浓度及RANKL/OPG比值与根尖片灰度值之间存在负相关关系(P<0.05).GCF中RANKL和OPG浓度及RANKL/OPG比值与PLI和SBI之间无相关关系(P>0.05).结论:RANKL和OPG在慢性牙周炎患者的牙槽骨组织破坏过程中发挥作用.     

Effect of tension-force on plasminogen activator activity from human periodontal ligament cells

The plasminogen activator (PA)-plasmin proteolytic system has recently received considerable attention because of its participation in a wide variety of biological activities and in pathological conditions involving tissue destruction. Excessive mechanical stress such as occlusal trauma is associated with alveolar bone loss in severe periodontitis. Therefore, mechanical stress may involve degradation of the extracellular matrix by occlusal trauma through activation of the PA-plasmin proteolytic system. We examined the effects of mechanical stress on PA activity, gene expressions of tissue type (t) PA, urokinase type (u) PA and PA inhibitor-1 (PAI-1) in human PDL cells. Human PDL cells were cultured on flexible-bottomed culture plates and placed on a Flexercell Strain Unit. The cells were flexed at 6 cycles (5 s strain, 5 s relaxation) at 9% and 18% elongation for 5 d. Application of tension-force induced significantly higher PA activity in stressed PDL cells than in non-stressed controls, and did so in a time- and magnitude-dependent manner (p<0.001, ANOVA). Western-blot analysis revealed that the high level of activity was due to tPA and not uPA. Gene expression of tPA mRNA in stressed PDL cells, as examined by RT-PCR, increased on d 5. These findings suggest that tPA may be involved in periodontal metabolism in response to mechanical stress.     

Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by Porphyromonas endodontalis in human pulp cells

AIM: To investigate the tissue type plasminogen activator (t-PA) activity in human pulp cells stimulated with Porphyromonas endodontalis (P. endodontalis) in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002. METHODOLOGY: The supernatants of P. endodontalis were used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search for possible signal transduction pathways, SB203580, U0126 and LY294002 were added to test how they modulated the t-PA activity. RESULTS: The main casein secreted by human pulp cells migrated at 70 kDa and represented t-PA. Secretion of t-PA was found to be stimulated with P. endodontalis during 2-day cultured period (P < 0.05). From the results of casein zymography and ELISA, SB203580 and U0126 significantly reduced the P. endodontalis stimulated t-PA production respectively (P < 0.05). However, LY294002 lacked the ability to change the P. endodontalis stimulated t-PA production (P > 0.05). CONCLUSIONS: Porphyromonas endodontalis enhances t-PA production in human pulp cells, and the signal transduction pathways p38 and MEK are involved in the inhibition of t-PA.     

可溶性凝集素样氧化型低密度脂蛋白受体 -1在急性缺血性脑卒中表达及与静脉溶栓预后和静脉溶栓后脑出血转化的关系

目的探讨可溶性凝集素样氧化型低密度脂蛋白受体 -1(sLOX-1)在急性缺血性脑卒中( AIS)表达及与静脉溶栓预后和静脉溶栓后脑出血转化的关系。方法选取 2017年 3月至 2020年 6月南京市高淳人民医院 AIS病人 104例,酶联免疫吸附法(ELISA)法测定血清 sLOX-1水平,比较 sLOX-1表达高低与病人临床资料的关系,分析 sLOX-1与 AIS病人静脉溶栓预后和静脉溶栓后脑出血转化的关系。结果相比于低 sLOX-1表达组,高 sLOX-1表达组病症更加严重,美国国立卫生院卒中量表(NHISS)评分显著增大,白细胞显著升高,肾小球滤过率估算值( eGFR)尿酸(UA)显著降低(均 P<0.05);行重组组织型纤溶酶原( rt-PA)静脉溶栓治疗预后不良组 sLOX-1表达显著高于预后良好组［(2、.18±0.71)比( 1.67±0.53)］;多因素 logistic回归模型结果发现经过年龄、溶栓时间、 NHISS评分、 eGFR等校正过后, sLOX-1［OR=3.83,95%CI:(1.77,5.12)P=0.007］仍然是行 rt-PA静脉溶栓 AIS病人预后的独立危险因素,经过年龄、 NHISS评分、溶栓时间等校正过后, sLOX-1［OR=1.84,9,5%CI:(1.12,2.54)P= 0.020］也仍然是 AIS病人发生脑出血性转化( HT)的独立危险因素。结论血清 sLOX-1是行 rt-PA静脉溶栓 AIS病人预后立危险因素,也是 AIS病人发生脑 HT的独立危险因素。     

Chemistry-led investigations into the mode of action of NAMPT activators,resulting in the discovery of non-pyridyl class NAMPT activators

The cofactor nicotinamide adenine dinucleotide (NAD⁺) plays a key role in a wide range of physiological processes and maintaining or enhancing NAD⁺ levels is an established approach to enhancing healthy aging. Recently, several classes of nicotinamide phosphoribosyl transferase (NAMPT) activators have been shown to increase NAD⁺ levels in vitro and in vivo and to demonstrate beneficial effects in animal models. The best validated of these compounds are structurally related to known urea-type NAMPT inhibitors, however the basis for the switch from inhibitory activity to activation is not well understood. Here we report an evaluation of the structure activity relationships of NAMPT activators by designing, synthesising and testing compounds from other NAMPT ligand chemotypes and mimetics of putative phosphoribosylated adducts of known activators. The results of these studies led us to hypothesise that these activators act via a through-water interaction in the NAMPT active site, resulting in the design of the first known urea-class NAMPT activator that does not utilise a pyridine-like warhead, which shows similar or greater activity as a NAMPT activator in biochemical and cellular assays relative to known analogues.