Celastrol protects human neuroblastoma SH-SY5Y cells from rotenone-induced injury through induction of autophagy

Celastrol, an active component found in the Chinese herb tripterygium wilfordii has been identified as a neuroprotective agent for neurodegenerative diseases including Parkinson’s disease (PD) through unknown mechanism. Celastrol can induce autophagy, which plays a neuroprotective role in PD. We tested the protective effect of celastrol on rotenone-induced injury and investigated the underlying mechanism using human neuroblastoma SH-SY5Y cells. The SH-SY5Y cells were treated with celastrol before rotenone exposure. The cells survival, apoptosis, accumulation of α-synuclein, oxidative stress and mitochondrial function, and autophagy production were analyzed. We found celastrol (500 nM) pre-treatment enhanced cell viability (by 28.99%, P < 0.001), decreased cell apoptosis (by 54.38%, P < 0.001), increased SOD and GSH (by 120.53% and 90.46%, P < 0.01), reduced accumulation of α-synuclein (by 35.93%, P < 0.001) and ROS generation (by 33.99%, P < 0.001), preserved MMP (33.93 ± 3.62%, vs. 15.10 ± 0.71% of JC-1 monomer, P < 0.001) and reduced the level of cytochrome C in cytosol (by 45.57%, P < 0.001) in rotenone treated SH-SY5Y cells. Moreover, celastrol increased LC3-II/LC3 I ratio by 60.92% (P < 0.001), indicating that celastrol activated autophagic pathways. Inhibiting autophagy by 3-methyladenine (3-MA) abolished the protective effects of celastrol. Our results suggested that celastrol protects SH-SY5Y cells from rotenone induced injuries and autophagic pathway is involved in celastrol neuroprotective effects.     

Mononuclear and dinuclear peroxotungsten complexes with co-ordinated dipeptides as potent inhibitors of alkaline phosphatase activity

New molecular peroxotungstate(VI) complexes with dipeptides as ancillary ligands of the type, [WO(O₂)₂(dipeptide)(H₂O)].3H₂O, dipeptide = glycyl-glycine or glycyl-leucine, have been synthesized and characterized by elemental analysis, spectral and physico-chemical methods including thermal analysis. The complexes contain side-on bound peroxo groups and a peptide zwitterion bonded to the metal centre unidentately through an O(carboxylate) atom. Investigations on certain biologically important key properties of these compounds and a set of dimeric compounds in analogous co-ligand environment, Na₂[W₂O₃(O₂)₄(dipeptide)₂].3H₂O, dipeptide = glycyl-glycine and glycyl-leucine, reported previously by us revealed interesting features of the compounds. Each of the compounds despite having a 7 co-ordinated metal centre exerts a strong inhibitory effect on alkaline phosphatase activity with a potency higher than that of the free dipeptide, tungstate or peroxotungstate. The compounds exhibit remarkable stability in solutions of acidic as well as physiological pH and are weaker as substrate to the enzyme catalase, compared to H₂O₂. The mononuclear and dinuclear peroxotungsten compounds are efficient oxidants of reduced glutathione (GSH), a reaction in which only one of the peroxo groups of a diperoxotungsten moiety of the complexes was found to be active.     

Lactacystin, a proteasome inhibitor, enhances BMP-induced osteoblastic differentiation by increasing active Smads

Proteasome inhibitors enhance bone formation and osteoblastic differentiation in vivo and in vitro. In the present study, we examined whether the molecular mechanisms of lactacystin, one of many proteasome inhibitors, stimulated the osteoblastic differentiation of C2C12 cells that is induced by bone morphogenetic proteins (BMPs). Pretreatment with lactacystin enhanced the alkaline phosphatase (ALP) activity induced by BMP2, BMP4 or BMP7, but lactacystin did not induce ALP in the absence of BMPs. In addition, lactacystin-stimulated BMP2 induced mRNA expression of ALP, type I collagen, osteonectin, osteocalcin, Id1, Osterix, and Runx2. Lactacystin maintained BMP2-induced phosphorylation of Smad1/5/8 and increased the length of time that these Smads were bound to target DNA. Moreover, lactacystin prevented BMP receptor-induced Smad degradation. This enhancement of BMP2-induced ALP activity and Smad phosphorylation by lactacystin was also observed in primary osteoblasts. These findings suggest that pretreatment with lactacystin accelerates BMP-induced osteoblastic differentiation by increasing the levels of phosphorylated Smads, which are maintained because BMP receptor-induced degradation is inhibited. We propose that optimized stimulation by proteasome inhibitors in a clinical setting may facilitate autogenous or BMP-induced bone formation in areas of defective bone.     

Lung cancer-derived Dickkopf1 is associated with bone metastasis and the mechanism involves the inhibition of osteoblast differentiation

Wnt/β-catenin signaling and Dickkopf1 (DKK1) play important roles in the progression of lung cancer, which preferably metastasizes to skeleton. But the role of them in bone dissemination is poorly understood. This study aims to define the role of DKK1 in lung cancer bone metastases and investigate the underlying mechanism. Our results demonstrated that DKK1 over-expression was a frequent event in non-small-cell lung cancer (NSCLC) blood samples, and serous DKK1 level was much higher in bone metastatic NSCLC compared to non-bone metastatic NSCLC. We also found that conditioned medium from DKK1 over-expressing lung cancer cells inhibited the differentiation of osteoblast, determined by alkaline phosphatase activity and osteocalcin secretion, whereas the conditioned medium from DKK1 silencing lung cancer cells exhibited the opposite effects. Mechanistically, DKK1 reduced the level of β-catenin and RUNX2, as well as inhibiting the nuclear translocation of β-catenin. Taken together, these results suggested that lung cancer-produced DKK1 may be an important mechanistic link between NSCLC and bone metastases, and targeting DKK1 may be an effective method to treat bone metastase of NSCLC.     

Phosphatidylcholine metabolism and choline kinase in human osteoblasts

There is a paucity of information about phosphatidylcholine (PC) biosynthesis in bone formation. Thus, we characterized PC metabolism in both primary human osteoblasts (HOB) and human osteosarcoma MG-63 cells. Our results show that the CDP-choline pathway is the only de novo route for PC biosynthesis in both HOB and MG-63 cells. Both CK activity and CKα expression in MG-63 cells were significantly higher than those in HOB cells. Silencing of CKα in MG-63 cells had no significant effect on PC concentration but decreased the amount of phosphocholine by approximately 80%. The silencing of CKα also reduced cell proliferation. Moreover, pharmacological inhibition of CK activity impaired the mineralization capacity of MG-63 cells. Our data suggest that CK and its product phosphocholine are required for the normal growth and mineralization of MG-63 cells.     

AT2R − 1332 G:A polymorphism and its interaction with AT1R 1166 A:C,ACE I/D and MMP-9 − 1562 C:T polymorphisms: Risk factors for susceptibility to preeclampsia

The possible association of angiotensin type 2 receptor (AT2R) − 1332 G:A polymorphism with susceptibility to preeclampsia was studied in 252 women consisted of 155 women with preeclampsia and 97 healthy pregnant women. Also, the interaction of this polymorphism with angiotensin type 1 receptor (AT1R) 1166 A:C, angiotensin converting enzyme insertion/deletion (ACE I/D) and also with matrix metalloproteinase-9 (MMP-9) − 1562 C:T polymorphism was investigated. The AT2R − 1332 G:A polymorphism was detected using PCR–RFLP method. Significantly higher frequencies of GG+GA genotype and G allele of AT2R were observed in mild (80.2%, p = 0.003 and 47.5%, p = 0.012, respectively) and severe (77.8%, p = 0.034 and 48.1%, p = 0.026, respectively) preeclampsia compared to controls (60.8% and 35.1%, respectively). The presence of G allele was associated with 1.69-fold increased risk of preeclampsia (p = 0.005). In severe preeclamptic women, systolic and diastolic blood pressures in the presence of GG+GA genotype were significantly higher compared to those in the presence of AA genotype. The concomitant presence of both alleles of AT2R G and AT1R C was associated with 1.3 times increased risk of mild preeclampsia (p = 0.03). There was an interaction between AT2R G and ACE D alleles that significantly increased the risk of mild and severe preeclampsia by 1.38- and 1.3-fold, respectively. Also, interaction between MMP-9 T and AT2R G alleles increased the risk of severe preeclampsia 1.39-fold (p = 0.028). Our study demonstrated that the G allele of AT2R − 1332 G:A polymorphism is associated with an increased risk of preeclampsia. Also, epistatic interaction of G allele and each allele of the AT1R C, ACE D and MMP-9 T was associated with the risk of preeclampsia. Our findings suggest that the renin–angiotensin system (RAS) variants and gene–gene interactions affect the risk of preeclampsia.     

Phytotherapeutic efficacy of the medicinal plant Terminalia catappa L.

Diabetes is a chronic, lifelong condition due to inadequate production of insulin or the cells does not properly respond it. Recently, the significance and effectiveness of herbal drugs associated with diabetes has emerged. The aim of the present study was to determine the anti-diabetic effects of Terminalia catappa L. leaves on streptozotocin (STZ)-treated rats. Two different concentrations of ethanolic leaf extract (300 and 500 mg/kg) of T. catappa were used to treat diabetic rats, and biochemical parameters were analyzed in blood samples. The results of herbal treatments were compared with the standard drug, glibenclamide. The ethanol extract (500 mg/kg) had significant anti-diabetic activity by altering blood glucose, glycosylated hemoglobin, liver glycogen, glucose 6-phosphatase, fructose 1,6-bisphosphatase, glucokinase, aspartate transaminase, alanine transaminase, alkaline phosphatase, urea, uric acid and creatinine levels while increasing insulin levels. Thus, the present study suggests that the supplementation of the diabetic patients with T. catappa leaves can lead to recovery from diabetic effects.     

The Identification of Marker Genes for Predicting the Osteogenic Differentiation Potential of Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) have the potential to differentiate into a variety of mature cell types and are a promising source of regenerative medicine. The success of regenerative medicine using MSCs strongly depends on their differentiation potential. In this study, we sought to identify marker genes for predicting the osteogenic differentiation potential by comparing ilium MSC and fibroblast samples. We measured the mRNA levels of 95 candidate genes in nine ilium MSC and four fibroblast samples before osteogenic induction, and compared them with alkaline phosphatase (ALP) activity as a marker of osteogenic differentiation after induction. We identified 17 genes whose mRNA expression levels positively correlated with ALP activity. The chondrogenic and adipogenic differentiation potentials of jaw MSCs are much lower than those of ilium MSCs, although the osteogenic differentiation potential of jaw MSCs is comparable with that of ilium MSCs. To select markers suitable for predicting the osteogenic differentiation potential, we compared the mRNA levels of the 17 genes in ilium MSCs with those in jaw MSCs. The levels of 7 out of the 17 genes were not substantially different between the jaw and ilium MSCs, while the remaining 10 genes were expressed at significantly lower levels in jaw MSCs than in ilium MSCs. The mRNA levels of the seven similarly expressed genes were also compared with those in fibroblasts, which have little or no osteogenic differentiation potential. Among the seven genes, the mRNA levels of IGF1 and SRGN in all MSCs examined were higher than those in any of the fibroblasts. These results suggest that measuring the mRNA levels of IGF1 and SRGN before osteogenic induction will provide useful information for selecting competent MSCs for regenerative medicine, although the effectiveness of the markers is needed to be confirmed using a large number of MSCs, which have various levels of osteogenic differentiation potential.