Xiaozhou Ying

Piperine inhibits IL-β induced expression of inflammatory mediators in human osteoarthritis chondrocyte

Black pepper (Piper nigrum) is a common remedy in Traditional Chinese Medicine and possesses diverse biological activities including anti-inflammatory properties. Osteoarthritis (OA) is a degenerative joint disease with an inflammatory component that drives the degradation of cartilage extracellular matrix. The present study aimed to assess the effects of piperine, the active phenolic component in black pepper extract, on human OA chondrocytes. In this study, human OA chondrocytes were pretreated with piperine at 10, 50 or 100μg/ml and subsequently stimulated with IL-1β (5ng/ml) for 24h. Production of PGE2 and NO was evaluated by the Griess reaction and an ELISA. Gene expression of MMP-3, MMP-13, iNOS and COX-2 was measured by real-time PCR. MMP-3 and MMP-13 proteins in culture medium were determined using cytokine-specific ELISA. Western immunoblotting was used to analyze the iNOS and COX-2 protein production in the culture medium. The regulation of NF-kB activity and the degradation of IkB were explored using luciferase and Western immunoblotting, respectively. We found that piperine inhibited the production of PGE2 and NO induced by IL-1β. Piperine significantly decreased the IL-1β-stimulated gene expression and production of MMP-3, MMP-13, iNOS and COX-2 in human OA chondrocytes. Piperine inhibited the IL-1β-mediated activation of NF-κB by suppressing the degradation of its inhibitory protein IκBα in the cytoplasm. The present report is first to demonstrate the anti-inflammatory activity of piperine in human OA chondrocytes. Piperine can effectively abrogate the IL-1β-induced over-expression of inflammatory mediators; suggesting that piperine may be a potential agent in the treatment of OA.

Antitumor and anti-angiogenesis effects of thymoquinone on osteosarcoma through the NF-κB pathway

Thymoquinone (TQ), the predominant bioactive constituent derived from the medicinal spice Nigella sativa (also known as black cumin), has been applied for medical purposes for more than 2,000 years. Recent studies reported that thymoquinone exhibited inhibitory effects on the cell proliferation of several cancer cell lines. This study was performed to investigate the antitumor and anti-angiogenic effects of thymoquinone on osteosarcoma in vitro and in vivo. Our results showed that thymoquinone induced a higher percentage of growth inhibition and apoptosis in the human osteosarcoma cell line SaOS-2 compared to that of control, and thymoquinone significantly blocked human umbilical vein endothelial cell (HUVEC) tube formation in a dose-dependent manner. To investigate the possible mechanisms involved in these events, we performed electrophoretic mobility shift assay (EMSA) and western blot analysis, and found that thymoquinone significantly downregulated NF-κB DNA-binding activity, XIAP, survivin and VEGF in SaOS-2 cells. Moreover, the expression of cleaved caspase-3 and Smac were upregulated in SaOS-2 cells after treatment with thymoquinone. In addition to these in vitro results, we also found that thymoquinone inhibits tumor angiogenesis and tumor growth through suppressing NF-κB and its regulated molecules. Collectively, our results demonstrate that thymoquinone effectively inhibits tumor growth and angiogenesis both in vitro and in vivo. Moreover, inhibition of NF-κB and downstream effector molecules is a possible underlying mechanism of the antitumor and anti-angiogenic activity of thymoquinone in osteosarcoma.

Piperine inhibits LPS induced expression of inflammatory mediators in RAW 264.7 cells

The aim of the present study was to investigate the effects of piperine on the inflammatory responses to lipopolysaccharide (LPS) in RAW264.7 cells and the signal transduction pathways involved. RAW264.7 cells were pretreated with piperine at 10, 50 or 100 μg/ml and subsequently stimulated with LPS (1 μg/ml) for 24 h. We found that piperine inhibited the production of prostaglandin E2 (PGE2) and nitric oxide (NO) induced by LPS. Piperine significantly decreased LPS-stimulated gene expression and production of tumor necrosis factor-alpha (TNF), inducible NO synthase (iNOS) and COX-2 in RAW264.7 cells. Piperine inhibited the LPS-mediated activation of nuclear factor-kappa B (NF-kappaB) by suppressing the degradation of inhibitor-κB proteins (IκB) and the translocations of p65 subunit of NF-kB from the cytosol to the nucleus. Our results demonstrate the anti-inflammatory activity of piperine in RAW264.7 cells; suggesting that piperine may be a potential agent in the treatment of inflammation.

Silibinin promotes osteoblast differentiation of human bone marrow stromal cells via bone morphogenetic protein signaling

Silibinin is the major active constituent of the natural compound silymarin; several studies suggest that silibinin possesses antihepatotoxic properties and anticancer effects against carcinoma cells. However, no study has yet investigated the effect of silibinin on osteogenic differentiation of human bone marrow stem cells (hBMSCs). The aim of this study was to evaluate the effect of silibinin on osteogenic differentiation of hBMSCs. In this study, the hBMSCs were cultured in an osteogenic medium with 0, 1, 10 or 20 μmol/l silibinin respectively. hBMSCs viability was analyzed by cell number quantification assay and cells osteogenic differentiation was evaluated by alkaline phosphatas (ALP) activity assay, Von Kossa staining and real time-polymerase chain reaction (RT-PCR). We found that silibinin promoted ALP activity in hBMSCs without affecting their proliferation. The mineralization of hBMSCs was enhanced by treatment with silibinin. Silibinin also increased the mRNA expressions of Collagen type I (COL-I), ALP, Osteocalcin (OCN), Osterix, bone morphogenetic protein-2 (BMP-2) and Runt-related transcription factor 2 (RUNX2). The BMP antagonist noggin and its receptor kinase inhibitors dorsomorphin and LDN-193189 attenuated silibinin-promoted ALP activity. Furthermore, BMP-responsive and Runx2-responsive reporters were activated by silibinin treatment. These results indicate that silibinin enhances osteoblast differentiation probably by inducing the expressions of BMPs and activating BMP and RUNX2 pathways. Thus, silibinin may play an important therapeutic role in osteoporosis patients by improving osteogenic differentiation of BMSCs.

Engineering scaffolds integrated with calcium sulfate and oyster shell for enhanced bone tissue regeneration.

Engineering scaffolds combinging natural biomineral and artificially synthesized material hold promising potential for bone tissue regeneration. In this study, novel bioactive calcium sulfate/oyster shell (CS/OS) composites were prepared. Comparing to CS scaffold, the CS/OS composites with a controllable degradation rate displayed enhanced mineral nodule formation, higher alkaline phosphate (ALP) activity and increased proliferation rate while treated osteocytes. In CS/OS composites group, elevated mRNA levels of key osteogenic genes including bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osterix (Osx), and osteocalcin (OCN) were observed. Furthermore, The up-regulation of BMP-2 and type I collagen (COL-I) was observed for CS/OS composites relative to a CS group. Scaffolds were implanted into critical-sized femur cavity defects in rabbits to investigate the osteogenic capacity of the composites in vivo. The CS/OS scaffolds with proper suitable times and mechanical strength strongly promoted osteogenic tissue regeneration relative to the regeneration capacity of CS scaffolds, as indicated by the results of histological staining. These results suggest that the OS-modified CS engineering scaffolds with improved mechanical properties and bioactivity would facilitate the development of a new strategy for clinic bone defect regeneration.

Myricetin enhances osteogenic differentiation through the activation of canonical Wnt/β-catenin signaling in human bone marrow stromal cells.

Myricetina flavonoid compound, has been reported to possess antioxidative, antiproliferative and anti-inflammatory effects. However, no study has yet investigated the effect of myricetin on osteogenic differentiation of human bone marrow stem cells (hBMSCs). This study was designed to investigate the effects of myricetin on osteogenic differentiation of hBMSCs in vitro. Cell viability was analyzed by MTT and osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity assay, Alizarin red S dye, real time-polymerase chain reaction (RT-PCR) and Western blot analysis. We found that the ALP activity and the mineralization of hBMSCs were enhanced by treatment with myricetin. Myricetin increased the mRNA expressions of Osteocalcin (OCN), Collagen type I (COL-I), ALP and Runt-related transcription factor 2 (RUNX2). Additionally, we found that myricetin activated the Wnt/β-catenin pathway and increased the expression of several downstream genes including T-cell factor-1(TCF-1) and lymphoid enhancer factor-1 (LEF-1). Depletion of β-catenin almost completely blocked the positive role of myricetin on osteogenic differentiation. Taken together, our findings suggest that myricetin enhanced osteogenic differentiation of hBMSCs by activating the Wnt/β-catenin signaling. The study may aid in the development of a therapeutic approach utilizing myricetin for the enhancement of bone health and prevention of osteoporosis.

The hepatoprotective effect of fraxetin on carbon tetrachloride induced hepatic fibrosis by antioxidative activities in rats

The aim of the study was to investigate the potentially protective effects of fraxetin on carbon tetrachloride (CCl4) induced oxidative stress and hepatic fibrosis in Sprague-Dawley rats. In this study, rats were divided into five groups, including normal controls, model, silymarin as the positive control, fraxetin 20 mg/kg and fraxetin 50 mg/kg. After 8 weeks, activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBIL) were checked. The levels of protein carbonyls, thiobarbituric acid-reactive substances (TBARS) and antioxidant enzymes such as catalase, SOD and glutathione peroxidase (GSH-Px) were determined after fraxetin administration. The hydroxyproline levels and histopathologic examinations of hepatocyte fibrosis were also determined. We found that fraxetin at doses of 20 and 50 mg/kg for 8 weeks significantly reduced the levels of TBARS and protein carbonyls compared with CCl4 group. Fraxetin significantly increased the activities of catalase, SOD and GSH-Px in the liver. We also found that fraxetin prevented CCl4 induced hepatic fibrosis by histological observations. These results indicate that fraxetin exhibits potent protective effects against CCl4 induced oxidative stress and hepatic fibrosis.

Silibinin alleviates high glucose-suppressed osteogenic differentiation of human bone marrow stromal cells via antioxidant effect and PI3K/Akt signaling.

High glucose is one of the possible causes for osteoporosis and fracture in diabetes mellitus. Our previous study showed that silibinin can increase osteogenic effect by stimulating osteogenic genes expression in human bone marrow stem cells (hBMSCs). However, no study has yet investigated the effect of silibinin on osteogenic differentiation of hBMSCs cultured with high glucose. The aim of this study was to evaluate the influence of high glucose on osteogenic differentiation of hBMSCs and to determine if silibinin can alleviate those effects. In this study, the hBMSCs were cultured in an osteogenic medium with physiological (normal glucose, NG, 5.5mM) or diabetic (high glucose, HG, 30mM). The effects of silibinin on HG-induced osteogenic differentiation were evaluated by alkaline phosphatas (ALP) activity assay, Von Kossa staining and real time-polymerase chain reaction. HG-induced oxidative damage was also assessed. Western blot were performed to examine the role of PI3K/Akt pathway. We demonstrated that HG suppressed osteogenic differentiation of hBMSCs, manifested by a decrease in expression of osteogenic markers and an increase of oxidative damage markers including reactive oxygen species and lipid peroxide (MDA). Remarkably, all of the observed oxidative damage and osteogenic dysfunction induced by HG were inhibited by silibinin. Furthermore, the PI3K/Akt pathway was activated by silibinin. These results demonstrate that silibinin may attenuate HG-mediated hBMSCs dysfunction through antioxidant effect and modulation of PI3K/Akt pathway, suggesting that silibinin may be a superior drug candidate for the treatment of diabetes related bone diseases.

Dose-dependent effects of nicotine on proliferation and differentiation of human bone marrow stromal cells and the antagonistic action of vitamin C.

A range of biological and molecular effects caused by nicotine are considered to effect bone metabolism. Vitamin C functions as a biological antioxidant. This study was to evaluate the in vitro effects of nicotine on human bone marrow stromal cells and whether Vitamin C supplementation show the antagonism action to high concentration nicotine. We used CCK‐8, alkaline phosphatase (ALP) activity assay, Von Kossa staining, real‐time polymerase chain reaction and Western Blot to evaluate the proliferation and osteogenic differentiation. The results indicated that the proliferation of BMSCs increased at the concentration of 50, 100 ng/ml, got inhibited at 1,000 ng/ml. When Vitamin C was added, the OD for proliferation increased. For ALP staining, we found that BMSCs treated with 50 and 100 ng/ml nicotine showed a higher activity compared with the control, and decreased at the 1,000 ng/ml. Bone morphogenetic protein‐2 (BMP‐2) expression and the calcium depositions decreased at 100 and 1,000 ng/ml nicotine, while the addition of Vitamin C reversed the down regulation. By real‐time PCR, we detected that the mRNA expression of collagen type I (COL‐I) and ALP were also increased in 50 and 100 ng/ml nicotine groups (P < 0.05), while reduced at 1,000 ng/ml (P < 0.05). When it came to osteocalcin (OCN), the changes were similar. Taken all together, it is found that nicotine has a two‐phase effect on human BMSCs, showing that low level of nicotine could promote the proliferation and osteogenic differentiation while the high level display the opposite effect. Vitamin C could antagonize the inhibitory effect of higher concentration of nicotine partly. J. Cell. Biochem. 114: 1720–1728, 2013.

The protective effects of silibinin in the treatment of streptozotocin-induced diabetic osteoporosis in rats

Diabetic osteoporosis (DO) is a complication of diabetes mellitus. Our previous study showed that silibinin can attenuate high glucose mediated human bone marrow stem cells dysfunction through antioxidant effect. However, no study has yet investigated the effect of silibinin in diabetic rats. Therefore, we assessed the effects of silibinin on bone characteristics in streptozotocin-induced diabetic rats. The aim of our study was to determine whether providing silibinin in the different supplementation could prevent bone loss in diabetic rats or not. Rats were randomly divided into four groups: (1) control group (CG) (n=10); (2) diabetic group (DG) (n=10); (3) diabetic group with 50mgkg-1day-1 of silibinin orally (DG-50) (n=10); and (4) diabetic group with 100mgkg-1day-1 of silibinin orally (DG-100) (n=10). 12 weeks after streptozotocin (STZ) injection, the femora from all rats were assessed and oxidative stress was evaluated. Bone mineral density was significantly decreased in diabetic rats; these effects were prevented by treatment with silibinin (100mgkg-1day-1 orally). Similarly, in the DG and DG-50 groups, changes in microarchitecture of femoral metaphysis assessed by microcomputed tomography demonstrated simultaneous existence of diabetic osteoporosis; these impairments were prevented by silibinin (100mgkg-1day-1 orally). In conclusion, silibinin supplementation may have potential use as a possible therapy for maintaining skeletal health and these results can enhance the understanding of diabetic osteoporosis induced by diabetes.