The synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid-imidazolide alters transforming growth factor beta-dependent signaling and cell migration by affecting the cytoskeleton and the polarity complex

The anti-tumor synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO)-imidazolide (CDDO-Im) ectopically activates the transforming growth factor beta (TGFbeta)-Smad pathway and extends the duration of signaling by an undefined mechanism. Here we show that CDDO-Imdependent persistence of Smad2 phosphorylation is independent of Smad2 phosphatase activity and correlates with delayed TGFbeta receptor degradation and trafficking. Altered TGFbeta trafficking parallels the dispersal of EEA1-positive endosomes from the perinuclear region of CDDO-Im-treated cells. The effect of CDDO-Im on the EEA1 compartment led to an analysis of the cytoskeleton, and we observed that CDDO-Im alters microtubule dynamics by disrupting the microtubule-capping protein, Clip-170. Interestingly, biotinylated triterpenoid was found to localize to the polarity complex at the leading edge of migrating cells. Furthermore, CDDO-Im disrupted the localization of IQGAP1, PKCzeta, Par6, and TGFbeta receptors from the leading edge of migrating cells and inhibited TGFbeta-dependent cell migration. Thus, the synthetic triterpenoid CDDO-Im interferes with TGFbeta receptor trafficking and turnover and disrupts cell migration by severing the link between members of the polarity complex and the microtubule network.     

Potent memapsin 2 (beta-secretase) inhibitors: design, synthesis, protein-ligand X-ray structure, and in vivo evaluation

Structure-based design, synthesis, and biological evaluation of a series of peptidomimetic beta-secretase inhibitors incorporating hydroxyethylamine isosteres are described. We have identified inhibitor 24 which has shown exceedingly potent activity in memapsin 2 enzyme inhibitory (K(i) 1.8 nM) and cellular (IC(50)=1 nM in Chinese hamster ovary cells) assays. Inhibitor 24 has also shown very impressive in vivo properties (up to 65% reduction of plasma A beta) in transgenic mice. The X-ray structure of protein-ligand complex of memapsin 2 revealed critical interactions in the memapsin 2 active site.     

Semi-synthetic analogs of pinitol as potential inhibitors of TNF-α cytokine expression in human neutrophils

Semi-synthetic analogs of pinitol were subjected to screening by determining TNF-α expression in human neutrophils using flowcytometry. Among the tested compounds, three derivatives displayed more than 50% inhibition of TNF-α cytokine secretion in LPS induced stimulated neutrophils and can be considered as potent anti-inflammatory moieties.     

Clinical grade mesenchymal stem cells transdifferentiated under xenofree conditions alleviates motor deficiencies in a rat model of Parkinson's disease

Bone marrow derived mesenchymal stem cells (BMMSCs) is a valid, definitive candidate for repair of damaged tissues in degenerative disorders in general and neurological diseases in particular. We have standardized the processing conditions for proliferation of BMMSCs using xenofree medium and checked their in vitro and in vivo neurogenic potential.

Method

The proliferative potential of BMMSCs was analyzed using xenofree media and functionality checked by transplantation into Parkinson's disease (PD) animal models. In vitro neuronal differentiation was investigated by neuronal induction media supplemented with growth factors. Differentiated cells were characterized at cellular and molecular levels. In vitro functionality estimated by dopamine secretion.

Results

A pure population of BMMSCs showing an 8–10 fold expansion was obtained using xenofree media. On differentiation to neuronal lineage, they exhibited neuronal morphology. Detectable levels of dopamine (1.93 ng/ml) were secreted into the culture media of differentiated cells. There was a significant behavioural improvement in PD models 3 months post transplantation.

Conclusion

Our study demonstrates that BMMSCs can be transdifferentiated efficiently into functional dopaminergic neurons both in vitro and in vivo. This holds immense clinical potential as a replacement therapy for PD and other neurodegenerative diseases.     

Modulation of Th1/Th2 cytokines and inflammatory mediators by hydroxychavicol in adjuvant induced arthritic tissues

The present study was undertaken to investigate the anti-arthritic activity of hydroxychavicol (HC) a major phenolic compound isolated from the aqueous extract leaves of plant Piper betle (Piperaceae). The compound showed significant lowering of pro-inflammatory (Th1) cytokine levels in arthritic paw tissue homogenate supernatant viz. IL-2, IFN-γ, and TNF-α with maximum inhibition at higher dose levels of 2 and 4 mg/kg p.o. and enhanced the production of anti-inflammatory (Th2) cytokines IL-4 and IL-5 estimated by cytometric bead array immunoassay. Cytometric bead array uses the sensitivity of amplified fluorescence detection by flowcytometer to measure soluble analytes in a particle based immune assay. This assay can accurately quantitate five cytokines in a 50-μl sample volume. The T-helper (Th1) deviated cells produce detectable level of tumor necrosis factor (TNF-α), interleukin-2 (IL-2), and interferon-gamma (IFN-γ), while the Th2 deviated cells produce significant amount of interleukin-4 (IL-4) and interleukin-5 (IL-5). HC at graded doses also significantly decreased the expression of IL-1β, PGE₂, LTB₄, and nitric oxide levels showing significant inhibition of these parameters. Elevated levels of CD4⁺ T cell specific interferon-gamma (IFN-γ) in splenocytes of arthritic animals was also inhibited in treated animals. The oral LD₀ in both mice and rats was more than 1000 mg/kg.     

A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies

Over the last decade, gene expression microarrays have had a profound impact on biomedical research. The diversity of platforms and analytical methods available to researchers have made the comparison of data from multiple platforms challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and 'in-house' platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by quantitative real-time (QRT)-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent preprocessing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.     

Deletion of exon I of SMAD7 in mice results in altered B cell responses

The members of the TGF-beta superfamily, i.e., TGF-beta isoforms, activins, and bone morphogenetic proteins, regulate growth, differentiation, and apoptosis, both during embryonic development and during postnatal life. Smad7 is induced by the TGF-beta superfamily members and negatively modulates their signaling, thus acting in a negative, autocrine feedback manner. In addition, Smad7 is induced by other stimuli. Thus, it can fine-tune and integrate TGF-beta signaling with other signaling pathways. To investigate the functional role(s) of Smad7 in vivo, we generated mice deficient in exon I of Smad7, leading to a partial loss of Smad7 function. Mutant animals are viable, but significantly smaller on the outbred CD-1 mouse strain background. Mutant B cells showed an overactive TGF-beta signaling measured as increase of phosphorylated Smad2-positive B cells compared with B cells from wild-type mice. In agreement with this expected increase in TGF-beta signaling, several changes in B cell responses were observed. Mutant B cells exhibited increased Ig class switch recombination to IgA, significantly enhanced spontaneous apoptosis in B cells, and a markedly reduced proliferative response to LPS stimulation. Interestingly, LPS treatment reverted the apoptotic phenotype in the mutant cells. Taken together, the observed phenotype highlights a prominent role for Smad7 in development and in regulating the immune system's response to TGF-beta.