Osteoimmunology in orthodontic tooth movement

The skeletal and immune systems share a multitude of regulatory molecules, including cytokines, receptors, signaling molecules, and signaling transducers, thereby mutually influencing each other. In recent years, several novel insights have been attained that have enhanced our current understanding of the detailed mechanisms of osteoimmunology. In orthodontic tooth movement, immune responses mediated by periodontal tissue under mechanical force induce the generation of inflammatory responses with consequent alveolar bone resorption, and many regulators are involved in this process. In this review, we take a closer look at the cellular/molecular mechanisms and signaling involved in osteoimmunology and at relevant research progress in the context of the field of orthodontic tooth movement.     

Thrombopoietin stimulates megakaryocytopoiesis, myelopoiesis, and expansion of CD34+ progenitor cells from single CD34+Thy-1+Lin- primitive progenitor cells

Thrombopoietin (TPO) or MpI ligand is known to stimulate megakaryocyte (MK) proliferation and differentiation. To identify the earliest human hematopoietic cells on which TPO acts, we cultured single CD34+Thy- 1+Lin- adult bone marrow cells in the presence of TPO alone, with TPO and interleukin-3 (IL-3), or with TPO and c-kit ligand (KL) in the presence of a murine stromal cell line (Sys1). Two distinct growth morphologies were observed: expansion of up to 200 blast cells with subsequent differentiation to large refractile CD41b+ MKs within 3 weeks or expansion to 200-10,000 blast cells, up to 25% of which expressed CD34. The latter blast cell expansions occurred over a 3- to 6-week period without obvious MK differentiation. Morphological staining, analysis of surface marker expression, and colony formation analysis revealed that these populations consisted predominantly of cells committed to the myelomonocytic lineage. The addition of IL-3 to TPO-containing cultures increased the extent of proliferation of single cells, whereas addition of KL increased the percentage of CD34+ cells among the expanding cell populations. Production of multiple colony- forming unit-MK from single CD34+Thy-1+Lin- cells in the presence of TPO was also demonstrated. In limiting dilution assays of CD34+Lin- cells, TPO was found to increase the size and frequency of cobblestone areas at 4 weeks in stromal cultures in the presence of leukemia inhibitory factor and IL-6. In stroma-free cultures, TPO activated a quiescent CD34+Lin-Rhodamine 123lo subset of primitive hematopoietic progenitor cells into cycle, without loss of CD34 expression. These data demonstrate that TPO acts directly on and supports division of cells more primitive than those committed to the MK lineage.     

shRNA慢病毒对人口腔鳞状细胞癌细胞端粒酶卡侯体蛋白1基因的沉默效应

目的：探讨shRNA慢病毒对人口腔鳞状细胞癌Cal27细胞系端粒酶新蛋白,即端粒酶卡侯体蛋白1（TCAB1）基因的沉默效应,以期探索肿瘤基因治疗的新途径。方法：根据TCAB1基因,构建慢病毒shTCAB1-A~D,测定病毒滴度;用重组慢病毒体外感染Cal27细胞,荧光显微镜观察绿色荧光蛋白表达推断感染效率;半定量逆转录聚合酶链反应（RT-PCR）检测TCAB1 mRNA水平;Western blot检测TCAB1蛋白质的表达水平;四甲基偶氮唑盐比色（MTT）法检测细胞体外增殖能力;Transwell小室法检测细胞体外侵袭能力改变。结果：经PCR与测序鉴定证实成功构建靶向TCAB1的慢病毒RNAi载体,病毒滴度为1.5×108~3×108 U·mL-1。荧光显微镜观察显示,绝大部分细胞表达绿色荧光。与空白细胞对照组相比,4种不同的shTCAB1-A~D慢病毒感染组TCAB1 mRNA表达下调48.7%~62.0%;蛋白抑制率达45.6%~77.5%,shTCAB1-C组最明显。shTCAB1-C慢病毒能明显抑制Cal27细胞增殖能力,也能降低其侵袭能力,穿过人工基底膜的平均细胞数明显低于空白对照组及非特异性对照组,侵袭抑制率高达67.5%（P〈0.05）。结论：成功构建并包装了端粒酶新蛋白TCAB1靶向的RNAi慢病毒,该病毒可高效感染人口腔鳞状细胞癌细胞,产生特异性的基因沉默效应。