Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells.

BACKGROUND: The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years, which also may lead to some complications such as alveolar bone resorption or tooth root resorption. Low-intensity pulsed ultrasound (LIPUS), a noninvasive physical therapy, has been shown to promote bone fracture healing. It is also reported that LIPUS could reduce the duration of orthodontic treatment; however, how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear. AIM: To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement (OTM) model and explore the underlying mechanisms. METHODS: A rat model of OTM was established, and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction, Western blot, alkaline phosphatase (ALP) staining, and Alizarin red staining. The expression of Yes-associated protein (YAP1), the actin cytoskeleton, and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA (siRNA) application via immunofluorescence. RESULTS: The force treatment inhibited the osteogenic differentiation potential of hBMSCs; moreover, the expression of osteogenesis markers, such as type 1 collagen (COL1), runt-related transcription factor 2, ALP, and osteocalcin (OCN), decreased. LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force. Mechanically, the expression of LaminA/C, F-actin, and YAP1 was downregulated after force treatment, which could be rescued by LIPUS. Moreover, the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment. Consistently, LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo. The decreased expression of COL1, OCN, and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS. CONCLUSION: LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis, which may be a promising strategy to reduce the orthodontic treatment process.

PDRG1 gene silencing contributes to inhibit the growth and induce apoptosis of gastric cancer cells.

OBJECTIVE: This paper aims to provide some experimental basis for unveiling the role of PDRG1 (P53 And DNA Damage-Regulated Gene 1) gene silencing in the growth and development of gastric cancer. METHODS: PDRG1 levels in gastric cancer tissues and cell lines were measured by Western blotting. Then, gastric cancer BGC-823 cells, divided into Control, PDRG1 siRNA, NC siRNA and PDRG1 siRNA + KU55933 (ATM inhibitor) groups, were used to conduct a series of in vitro experiments including MTT, Flow cytometry, Wound-healing and Transwell assays. Expression of PDRG1 and ATM/p53 pathway-related proteins were determined by Western blot. Eventually, experiment in vivo was carried out to verify the control of PDRG1 on gastric cancer cells after establishing the tumor xenograft model in nude mice. RESULTS: PDRG1 was significantly elevated in gastric cancer tissues and was associated with lower cell differentiation degree, more severe lymph node metastasis and higher tumor stage of gastric cancer patients. The growth of BGC-823 cells were significantly retarded and the cell apoptosis was increased in the PDRG1 siRNA group; besides, cell cycle was arrested in G2/M phase, and the expressions of p-ATM, p53, p21, p-cdc2 and cleaved caspase-3 were up-regulated with the reduced PDRG1. However, KU55933 could reverse the anti-tumor effect of PDRG1 siRNA on BGC-823 cells. The in-vivo experiment confirmed PDRG1 siRNA can inhibit tumor xenograft growth in nude mice. CONCLUSION: Specific PDRG1 gene silencing may inhibit the growth and metastasis of gastric cancer cells through the activation of ATM/p53 pathway.

[Analysis of structure changes of microbial community in medium biofilm by ERIC-PCR fingerprinting].

A new technique, with medium biofilms and hydrophytes as main components, with microbes, plankton, hydrophytes and aquatic animals as basic ecological elements, was adopted to deal with eutrophication water in Shanghai. A pilot-scale test was carried on, with influent as 6 m(3)/d, 7 ponds parallelly connected, and with continuous influent and effluent. Water qualities were analyzed and ERIC-PCR fingerprinting method was used to study the natures of biofilm microbes. The results show that, the device has obvious affection on eutrophication water pollution removal, COD, TN, NH4+-N and TP removal efficiencies are respectively 20.7% - 48.5%, 20.1% - 49.7%, 39.8% - 66.2 % and 60.0% - 73.9% higher than those of control experiment. Water plants contribute for N and P absorption and removal, the three ponds with plants have higher TN and TP removal efficiency than the tree ones without hydrophytes, the enhanced TN removal efficiencies are 30.1%, 24.9% and 17.6% respectively. ERIC-PCR fingerprinting indicate that the three ponds with water plants have more similar microbial community structure to each other than no hydrophyte ponds, and that mean pairwise similarity coefficient value are 71.8% , 86.9% and 91.0% respectively on 2nd, 15th and 30th day, and at the same time the population diversity indexes rang from 1.89 to 2.22, 2.17 to 2.43 and 2.28 to 2.68, respectively. The above discussions conclude that the systemic population diversity indexes and structure similarity increase, biofilm microbes have gradually abundant population and stable structure, which are in accord with pollution removal efficiencies.