Fibulin2: a negative regulator of BMSC osteogenic differentiation in infected bone fracture healing.

Bone fracture remains a common occurrence, with a population-weighted incidence of approximately 3.21 per 1000. In addition, approximately 2% to 50% of patients with skeletal fractures will develop an infection, one of the causes of disordered bone healing. Dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays a key role in disordered bone repair. However, the specific mechanisms underlying BMSC dysfunction caused by bone infection are largely unknown. In this study, we discovered that Fibulin2 expression was upregulated in infected bone tissues and that BMSCs were the source of infection-induced Fibulin2. Importantly, Fibulin2 knockout accelerated mineralized bone formation during skeletal development and inhibited inflammatory bone resorption. We demonstrated that Fibulin2 suppressed BMSC osteogenic differentiation by binding to Notch2 and inactivating the Notch2 signaling pathway. Moreover, Fibulin2 knockdown restored Notch2 pathway activation and promoted BMSC osteogenesis; these outcomes were abolished by DAPT, a Notch inhibitor. Furthermore, transplanted Fibulin2 knockdown BMSCs displayed better bone repair potential in vivo. Altogether, Fibulin2 is a negative regulator of BMSC osteogenic differentiation that inhibits osteogenesis by inactivating the Notch2 signaling pathway in infected bone.

Matrix metalloproteinase-9 was involved in the immuno-modulatory defect of mesenchymal stem cell from chronic myeloid leukemia patients.

BACKGROUND: Overwhelming evidences on chronic myeloid leukemia (CML) indicate that patients harbor quiescent CML stem cells that are responsible for blast crisis. While the hematopoietic stem cell (HSC) origin of CML was first suggested over 30 years ago, recently CML-initiating cells beyond HSCs are also being investigated. METHODS: We have previously isolated fetal liver kinase-1-positive (Flk1(+)) cells carrying the BCR/ABL fusion gene from the bone marrow of Ph(+) patients with hemangioblast property. In this study, we isolated CML patient-derived Flk1(+)CD31(-)CD34(-) mesenchymal stem cells (MSCs) and detected their biological characteristics and immunological regulation using fluorescence in situ hybridization (FISH) analysis, fluorescence activated cell sorting (FACS), enzyme-linked immunoadsorbent assay, mixed lymphocyte reaction assays; then we compared these characters with those of the healthy donors. RESULTS: CML patient-derived Flk1(+)CD31(-)CD34(-) MSCs had normal morphology, phenotype and karyotype while appeared impaired in immuno-modulatory function. The capacity of patient Flk1(+)CD31(-)CD34(-) MSCs to inhibit T lymphocyte activation and proliferation was impaired in vitro. CONCLUSIONS: CML patient-derived MSCs have impaired immuno-modulatory functions, suggesting that the dysregulation of hematopoiesis and immune response may originate from MSCs rather than hematopoietic stem cells (HSCs). MSCs might be a potential target for developing efficacious treatment for CML.

Caudatin-2,6-dideoxy-3-O-methy-ß-D-cymaropyranoside 1 induced apoptosis through caspase 3-dependent pathway in human hepatoma cell line SMMC7721.

Caudatin-2,6-dideoxy-3-O-methy-ß-D-cymaropyranoside (CDMC), the C-21 steroidal glycoside recently extracted from the traditional Chinese medicinal plant, the root of Cynanchum auriculatum Royle ex Wight (Asclepiadaceae), has been shown to possess potent antitumor properties. However, the bioactivities of CDMC are still largely unknown, especially the antitumor effect and its mechanism. This study investigated the CDMC antitumor effects on human hepatoma cell line SMMC7721 cells by analysis of cell viability, cell cycle phases and apoptosis. The results showed that CDMC inhibited the growth of SMMC7721 cells in a time- and dose-dependent manner and resulted in cell cycle arrest in G(0)/G(1) phase. Furthermore, CDMC induced SMMC7721 cell apoptosis rather than necrosis through caspase 3 activation, and a caspase 3 inhibitor, Ac-DEVD-CHO, could attenuate the apoptosis induced by CDMC. The results suggested that the anticancer activity of CDMC could be attributed partially to its inhibition of cell proliferation and induction of apoptosis associated with caspase 3 activation.

Antitumor activity of C-21 steroidal glycosides from Cynanchum auriculatum Royle ex Wight.

The antitumor activities of six C-21 steroidal glycosides isolated from the root tuber of Cynanchum auriculatum Royle ex Wight were performed according to a microculture tetrazolium (MTT) method on human tumor cell lines SMMC-7721, MCF-7 and Hela. Of these compounds, caudatin-2,6-dideoxy-3-O-methy-ß-D-cymaropyranoside and caudatin were found to be of the highest effects against human tumor cell line SMMC-7721 with IC(50) values of 13.49 and 24.95 µM, respectively. Then the in vivo assay further showed that caudatin-2,6-dideoxy-3-O-methy-ß-D-cymaropyranoside and caudatin significantly inhibited the growth of transplantable H(22) tumors in mice.