Micro/nano topological modification of TiO2 nanotubes activates Thy-1 signaling to control osteogenic differentiation of stem cells.

Micro/nano topological modification is critical for improving the in vivo behaviors of bone implants, regulating multiple cellular functions. Titania (TiO2) nanotubes show the capacity of promoting osteoblast-related cell differentiation and induce effective osseointegration, serving as a model material for studying the effects of micro/nano-topological modifications on cells. However, the intracellular signaling pathways by which TiO2 nanotubes regulate the osteogenic differentiation of stem cells are not fully defined. Thy-1 (CD90), a cell surface glycoprotein anchored by glycosylphosphatidylinositol, has been considered a key molecule in osteoblast differentiation in recent years. Nevertheless, whether the micro/nano topology of the implant surface leads to changes in Thy-1 is unknown, as well as whether these changes promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Here, TiO2 nanotubes of various diameters were prepared by adjusting the anodizing voltage. qPCR and immunoblot were carried out to assess the mechanism by which TiO2 nanotubes regulate Thy-1. The results revealed Ti plates harboring TiO2 nanotubes ∼100-nm diameter (TNT-100) markedly upregulated Thy-1. Subsequently, upregulated Thy-1 promoted the activation of Fyn/RhoA/MLC Ⅱ/F-actin axis, which enhanced the nuclear translocation of YAP. After Thy-1 knockdown by siRNA, the Fyn/RhoA/MLC Ⅱ/F-actin axis was significantly inhibited and TiO2 nanotubes showed decreased effects on osteogenic differentiation. Therefore, Thy-1 upregulation might be a major mechanism by which micro/nano-topological modification of TiO2 nanotubes promotes osteogenic differentiation in BMSCs. This study provides novel insights into the molecular mechanism of TiO2 nanotubes, which may help design improved bone implants for clinical application.

Study on Different Components of Rhei Radix Et Rhizoma from 3 Different Origins Based on HPLC Fingerprint and UPLC- Q-TOF-MS / 中国药房

OBJECTIVE： To establish HPLC fingerprints of Rhei Radix Et Rhizoma from different origins， and identify the differential components qualitatively. METHODS： HPLC fingerprints of 30 batches of Rhei Radix Et Rhizoma （20 batches of Rheum palmatum， 5 batches of Rheum tanguticum and 5 batches of Rheum officinale） were established and similarity evaluation was performed by using Similarity Evaluation System for Chromatographic Fingerprint of TCM （2012 edition）. Qualitative identification of differential components of Rhei Radix Et Rhizoma from 3 different origins were performed by using PLS-DA combined with UPLC-Q-TOF-MS. RESULTS：The fingerprint similarities of 30 batches of samples were between 0.609 and 0.960. According to PLS-DA analysis， Rhei Radix Et Rhizoma were significantly aggregated into 3 groups according to the origin. There were 18 different components among 3 groups， which were identified by UPLC-Q-TOF-MS as resveratrol-4′-O-β-D-（6″-O-gallacyl）-glucoside， lindleyin， rhein-8-O-glucoside， epicatechin gallate， 4-（4′-hydroxyphenyl）-2-butanone-4′-O-β-D-（2″-O-cinnamyl-6″-O-gallacyl）-glucoside. CONCLUSIONS： Established method can effectively identify Rhei Radix Et Rhizoma from 3 different origins， and the differential components can be distinguished， which provides a reference for the identification and quality evaluation of multi-source medicinal materials.