Ameliorative effect of berberine on renal damage in rats with diabetes induced by high-fat diet and streptozotocin

Berberine (BBR) is one of the main constituents in Rhizoma coptidis and it has widely been used for the treatment of diabetic nephropathy. The aims of the study were to investigate the effects and mechanism of action of berberine on renal damage in diabetic rats. Diabetes and hyperglycaemia were induced in rats by a high-fat diet and intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Rats were randomly divided into 5 groups, such as i) control rats, ii) untreated diabetic rats iii) 250 mg/kg metformin-treated, iv and v) 100 and 200 mg/kg berberine-treated diabetic rats and treated separately for 8 weeks. The fasting blood glucose, insulin, total cholesterol, triglyceride, glycosylated hemoglobin were measured in rats. Kidneys were isolated at the end of the treatment for histology, Western blot analysis and estimation of malonaldehyde (MDA), superoxide dismutase (SOD) and renal advanced glycation endproducts (AGEs). The results revealed that berberine significantly decreased fasting blood glucose, insulin levels, total cholesterol, triglyceride levels, urinary protein excretion, serum creatinine (Scr) and blood urea nitrogen (BUN) in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with berberine. In addition, the protein expressions of nephrin and podocin were significantly increased. It seems likely that in rats berberine exerts an ameliorative effect on renal damage in diabetes induced by high-fat diet and streptozotocin. The possible mechanisms for the renoprotective effects of berberine may be related to inhibition of glycosylation and improvement of antioxidation that in turn upregulate the expressions of renal nephrin and podocin.     

Structural and functional insights into the heme-binding domain of the human soluble guanylate cyclase α2 subunit and heterodimeric α2β1

Soluble guanylate cyclase (sGC) mediates NO signaling for a wide range of physiological effects in the cardiovascular system and the central nervous system. The α1β1 isoform is ubiquitously distributed in cytosolic fractions of tissues, whereas α2β1 is mainly found in the brain. The major occurrence and the unique characteristic of human sGC α2β1 indicate a special role in the mediation of neuronal communication. We have efficiently purified and characterized the recombinant heme-binding domain of the human sGC α2 subunit (hsGC α2(H)) and heterodimeric α2β1 (hsGC β1(H)-α2(H)) by UV-vis spectroscopy, circular dichrosim spectroscopy, EPR spectroscopy, and homology modeling. The heme dissociation and related NO/CO binding/dissociation of both hsGC α2(H) and hsGC β1(H)-α2(H) were investigated. The two truncated proteins interact with heme noncovalently. The CO binding affinity of hsGC α2(H) is threefold greater than that of human sGC α1(H), whereas the dissociation constant k (1) for dissociation of NO from hsGC α2(H) is sevenfold larger than that for dissociation of NO from hsGC α1(H), although k (2) is almost identical. The results indicate that in comparison with the α1β1 isoform, the brain α2β1 isoform exhibits a distinctly different CO/NO affinity and binding rate in favor of NO signaling, and this is consistent with its physiological role in the activation and desensitization. Molecular modeling and sequence alignments are consistent with the hypothesis that His105 contributes to the different CO/NO binding properties of different isoforms. This valuable information is helpful to understand the molecular mechanism by which human sGC α2β1 mediates NO/CO signaling.     

A biofilm reactor-based approach for rapid on-line determination of biodegradable organic pollutants

A new analytical approach utilizing a biofilm reactor (BFR) for rapid online determination of biochemical oxygen demand (BOD) was proposed and experimentally validated. The BFR was fabricated via a cultivation process using naturally occurring microbial seeds from locally collected wastewaters. The resultant BFR displays a remarkable rate of biodegradation towards a wide spectrum of organic substrates, capable of degrading over 20% of biodegradable organic substrates within 100 s. More importantly, the BFR exhibits a superior indiscriminative biodegradation feature, enabling a precise prediction of BOD values of total biodegradable organics based on experimentally determined BOD values from partial degradation processes without a need for on-going calibration. The proposed approach was systematically validated using a range of individual organic substrates, their mixtures, synthetic samples and wastewaters. Highly significant linear correlations between the BFR and the standard BOD(5) methods were obtained from diversified synthetic samples (r=0.988, p=0.000, n=45) and wastewaters (r=0.983, p=0.000, n=40). Near unity slope values of the principal axis of the correlation ellipse were obtained from all tested samples, suggesting both methods were essentially measuring the same BOD value. The reported method could be a useful online monitoring tool for determination of biodegradable organic pollutants.     

Synthesis and biological evaluation of substituted pyrazoles as blockers of divalent metal transporter 1 (DMT1)

Three distinct series of substituted pyrazole blockers of divalent metal transporter 1 (DMT1) were elaborated from the high-throughput screening pyrazolone hit 1. Preliminary hit-to-lead efforts revealed a preference for electron-withdrawing substituents in the 4-amido-5-hydroxypyrazole series 6a-l. In turn, this preference was more pronounced in a series of 4-aryl-5-hydroxypyrazoles 8a-j. The representative analogs 6f and 12f were found to be efficacious in a rodent model of acute iron hyperabsorption. These three series represent promising starting points for lead optimization efforts aimed at the discovery of DMT1 blockers as iron overload therapeutics.     

An integrated approach to demonstrating the ANR pathway of proanthocyanidin biosynthesis in plants

Proanthocyanidins (PAs) are oligomers or polymers of plant flavan-3-ols and are important to plant adaptation in extreme environmental conditions. The characterization of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) has demonstrated the different biogenesis of four stereo-configurations of flavan-3-ols. It is important to understand whether ANR and the ANR pathway widely occur in the plant kingdom. Here, we report an integrated approach to demonstrate the ANR pathway in plants. This includes different methods to extract native ANR from different tissues of eight angiosperm plants (Lotus corniculatus, Desmodium uncinatum, Medicago sativa, Hordeum vulgare, Vitis vinifera, Vitis bellula, Parthenocissus heterophylla, and Cerasus serrulata) and one fern plant (Dryopteris pycnopteroides), a general enzymatic analysis approach to demonstrate the ANR activity, high-performance liquid chromatography-based fingerprinting to demonstrate (-)-epicatechin and other flavan-3-ol molecules, and phytochemical analysis of PAs. Results demonstrate that in addition to leaves of M. sativa, tissues of other eight plants contain an active ANR pathway. Particularly, the leaves, flowers and pods of D. uncinatum, which is a model plant to study LAR and the LAR pathways, are demonstrated to express an active ANR pathway. This finding suggests that the ANR pathway involves PA biosynthesis in D. uncinatum. In addition, a sequence BLAST analysis reveals that ANR homologs have been sequenced in plants from both gymnosperms and angiosperms. These data show that the ANR pathway to PA biosynthesis occurs in both seed and seedless vascular plants.     

Resveratrol inhibits inflammatory responses via the mammalian target of rapamycin signaling pathway in cultured LPS-stimulated microglial cells

Background

Resveratrol have been known to possess many pharmacological properties including antioxidant, cardioprotective and anticancer effects. Although current studies indicate that resveratrol produces neuroprotection against neurological disorders, the precise mechanisms for its beneficial effects are still not fully understood. We investigate the effect of anti-inflammatory and mechamisms of resveratrol by using lipopolysaccharide (LPS)-stimulated murine microglial BV-2 cells.

Methodology/Principal Findings

BV-2 cells were treated with resveratrol (25, 50, and 100 µM) and/or LPS (1 µg/ml). Nitric oxide (NO) and prostaglandin E2 (PGE2) were measured by Griess reagent and ELISA. The mRNA and protein levels of proinflammatory proteins and cytokines were analysed by RT-PCR and double immunofluorescence labeling, respectively. Phosphorylation levels of PTEN (phosphatase and tensin homolog deleted on chromosome 10), Akt, mammalian target of rapamycin (mTOR), mitogen-activated protein kinases (MAPKs) cascades, inhibitor κB-α (IκB-α) and cyclic AMP-responsive element-binding protein (CREB) were measured by western blot. Resveratrol significantly attenuated the LPS-induced expression of NO, PGE2, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nuclear factor-κB (NF-κB) in BV-2 cells. Resveratrol increased PTEN, Akt and mTOR phosphorylation in a dose-dependent manner or a time-dependent manner. Rapamycin (10 nM), a specific mTOR inhibitor, blocked the effects of resveratrol on LPS-induced microglial activation. In addition, mTOR inhibition partially abolished the inhibitory effect of resveratrol on the phosphorylation of IκB-α, CREB, extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK).

Conclusion and Implications

This study indicates that resveratrol inhibited LPS-induced proinflammatory enzymes and proinflammatory cytokines via down-regulation phosphorylation of NF-κB, CREB and MAPKs family in a mTOR-dependent manner. These findings reveal, in part, the molecular basis underlying the anti-inflammatory properties of resveratrol.     

Scientific publications on primary biliary cirrhosis from 2000 through 2010: an 11-year survey of the literature

Background

Primary biliary cirrhosis (PBC) is a chronic liver disease characterized by intrahepatic bile-duct destruction, cholestasis, and fibrosis. It can lead to cirrhosis and eventually liver failure. PBC also shows some regional differences with respect to incidence and prevalence that are becoming more pronounced each year. Recently, researchers have paid more attention to PBC. To evaluate the development of PBC research during the past 11 years, we determined the quantity and quality of articles on this subject. We also compared the contributions of scientists from the US, UK, Japan, Italy, Germany, and China.

Methods

The English-language papers covering PBC published in journals from 2000 through 2010 were retrieved from the PubMed database. We recorded the number of papers published each year, analyzed the publication type, and calculated the accumulated, average impact factors (IFs) and citations from every country. The quantity and quality of articles on PBC were compared by country. We also contrasted the level of PBC research in China and other countries.

Results

The total number of articles did not significantly increase during the past 11 years. The number of articles from the US exceeded those from any other country; the publications from the US also had the highest IFs and the most citations. Four other countries showed complex trends with respect to the quantity and quality of articles about PBC.

Conclusion

The researchers from the US have contributed the most to the development of PBC research. They currently represent the highest level of research. Some high-level studies, such as RCTs, meta-analyses, and in-depth basic studies should be launched. The gap between China and the advanced level is still enormous. Chinese investigators still have a long way to go.     

Reduction of mitoferrin results in abnormal development and extended lifespan in Caenorhabditis elegans

Iron is essential for organisms. It is mainly utilized in mitochondria for biosynthesis of iron-sulfur clusters, hemes and other cofactors. Mitoferrin 1 and mitoferrin 2, two homologues proteins belonging to the mitochondrial solute carrier family, are required for iron delivery into mitochondria. Mitoferrin 1 is highly expressed in developing erythrocytes which consume a large amount of iron during hemoglobinization. Mitoferrin 2 is ubiquitously expressed, whose functions are less known. Zebrafish with mitoferrin 1 mutation show profound hypochromic anaemia and erythroid maturation arrests, and yeast with defects in MRS3/4, the counterparts of mitoferrin 1/2, has low mitochondrial iron levels and grows poorly by iron depletion. Mitoferrin 1 expression is up-regulated in yeast and mouse models of Fiedreich's ataxia disease and in human cell culture models of Parkinson disease, suggesting its involvement in the pathogenesis of diseases with mitochondrial iron accumulation. In this study we found that reduced mitoferrin levels in C. elegans by RNAi treatment causes pleiotropic phenotypes such as small body size, reduced fecundity, slow movement and increased sensitivity to paraquat. Despite these abnormities, lifespan was increased by 50% to 80% in N2 wild type strain, and in further studies using the RNAi sensitive strain eri-1, more than doubled lifespan was observed. The pathways or mechanisms responsible for the lifespan extension and other phenotypes of mitoferrin RNAi worms are worth further study, which may contribute to our understanding of aging mechanisms and the pathogenesis of iron disorder related diseases.     

Novel potassium N-[(2S,3R,4R,5R)-2,3,4,5,6-pentahydroxylhex-1-yl]-L-amino acid dichloroplatinates(II) with high anti-tumor activity and low side reaction

To discover whether novel anti-tumor platinum agents are capable of selectively accumulating in tumor tissue, three novel potassium N-[(2S,3R,4R,5R)-2,3,4,5,6-pentahydroxylhex-1-yl]-L-amino acid dichloroplatinates(II) were prepared. At a dose of 1.67 μmol kg(-1) the in vivo anti-tumor potencies of two of the compounds were higher than that of oxaliplatin. The mortality analysis indicated that these compounds resulted in a 100% survival rate, whereas oxaliplatin lead to an 80% survival rate. The organ damage examination indicated that these compounds induced less damage than oxaliplatin. The platinum accumulation in the organs, blood and bone was significantly lower than that of oxaliplatin treated mice, while the platinum accumulation in the tumor tissue was significantly higher than that of the oxaliplatin treated mice.