Effects of glial cell line-derived neurotrophic factor on microRNA expression in a 6-hydroxydopamine-injured dopaminergic cell line

Parkinson's disease (PD) is the second most prevalent, progressive neurodegenerative disease and is characterized by the irreversible and selective loss of nigrostriatal dopaminergic (DA) neurons. Glial cell line-derived neurotrophic factor (GDNF), which is a potent protective factor for DA neurons, is considered a promising neuroprotective candidate for PD. microRNAs (miRNAs) have been shown to be involved in a number of neurodegenerative diseases. Both miRNAs and GDNF affect DA neuronal processes, but the molecular crosstalk between these molecules remains unclear. The present study aimed to evaluate whether GDNF modulates miRNA expression. We used microarray analysis and real-time polymerase chain reaction (RT-PCR) to investigate miRNAs expression in 6-hydroxydopamine (6-OHDA)-injured MN9D cells treated with GDNF for 30 min, 1 h, or 3 h. Our results showed that GDNF treatment led to differential expression of 143 miRNAs. To further identify mechanisms by which GDNF exerts its effects, we compared miRNAs and mRNAs microarray data at the 1-h time point. We found that various biological processes and pathways were regulated at the miRNA level following GDNF treatment. Collectively, these results provide evidence of the capacity of GDNF to influence miRNAs expression, suggesting a new mechanism of GDNF action.

Role of calbindin-D28K in estrogen treatment for Parkinson's disease

Studies have shown that estrogen has neuroprotective effects on the nigrostriatal system. The present study established a Parkinson's disease model in C57BL/6 mice by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrapyridine. The mice were subjected to 17β estradiol injection into the lateral ventricle. Immunofluorescence double staining showed that estrogen increased tyrosine hydroxylase and calbindin-D28K expression and co-expression in dopaminergic neurons of midbrain substantia nigra pars compacta of model mice. Behavior experiments showed that estrogen improved swimming and hanging behaviors in this mouse model of Parkinson's disease.

Rapid extraction and preservation of genomic DNA from human samples

Simple and rapid extraction of human genomic DNA remains a bottleneck for genome analysis and disease diagnosis. Current methods using microfilters require cumbersome, multiple handling steps in part because salt conditions must be controlled for attraction and elution of DNA in porous silica. We report a novel extraction method of human genomic DNA from buccal swab and saliva samples. DNA is attracted onto a gold-coated microchip by an electric field and capillary action while the captured DNA is eluted by thermal heating at 70 °C. A prototype device was designed to handle four microchips, and a compatible protocol was developed. The extracted DNA using microchips was characterized by qPCR for different sample volumes, using different lengths of PCR amplicon, and nuclear and mitochondrial genes. In comparison with a commercial kit, an equivalent yield of DNA extraction was achieved with fewer steps. Room-temperature preservation for 1 month was demonstrated for captured DNA, facilitating straightforward collection, delivery, and handling of genomic DNA in an environment-friendly protocol.

Involvement of N-cadherin in the protective effect of glial cell line-derived neurotrophic factor on dopaminergic neuron damage

The aim of this study was to further confirm that glial cell line-derived neurotrophic factor (GDNF) exerts a neuro-protective effect on dopaminergic neurons (DAs) and to investigate the protective mechanism. Cadherins are calcium-dependent adhesion proteins, and N-cadherins are found in neurons. Our study attempted to ascertain whether GDNF activates the PI3K/Akt signaling pathway through the mediation of N-cadherin to confer a protective effect on DAs. Flow cytometry and Hoechst 33258 staining results indicated that the apoptosis rate of damaged neurocytes increased following interference of N-cadherin expression. Immunoblotting results demonstrated that the amount of phosphorylated Akt (p-Akt) in the cytoplasm decreased, while the total Akt quantity remained unchanged following interference of N-cadherin expression. The immunohistochemical staining results demonstrated that the levels of total N-cadherin, phosphorylated N-cadherin (Tyr860) and p-Akt decreased; however, the amount of total Akt remained unchanged. In addition, we also demonstrated that Tyr860 and p-Akt levels were reduced in a GDNF dose-dependent manner with the phosphorylation level peaking at GDNF dose of 50 ng/ml (in vitro) and 50 ng/4 µl (in vivo), and also in a time-dependent manner with the phosphorylation level peaking at 15 min (in vitro) and 30 min (in vivo). Statistical analysis also showed that changes in the phosphorylation levels of Tyr860 and p-Akt demonstrated a positive correlation. Collectively, GDNF activates the PI3K/Akt pathway via N-cadherin to protect DAs.

First Report of Botryosphaeria dothidea Causing Canker and Dieback Disease of Helwingia chinensis in China

Helwingia chinensis Batal is distributed in the western and southern regions of China. The aerial part of this plant has long been used to treat dysentery, hematochezia, and swelling. An outbreak of cankers and dieback was observed for the first time on H. chinensis in China during June of 2010. Disease symptoms included dieback of shoots and branches, lesions, and canker formation on the stems. In order to identify the causal agent(s) of this canker disease, samples composed of inner bark and woody tissues were collected from the junction of healthy and diseased tissues of declining trees from Kunming and Wenshan districts of China during July to October of 2010. Pieces of surface-sterilized tissue samples were plated on potato dextrose agar (PDA) and incubated at 26°C. Fungal colonies developed copious, white, aerial mycelium that became dark green with age. Pycnidia started to develop after 20 days. Macroconidia, which were 20 to 29 × 4 to 6 μm, were hyaline, aseptate, and fusiform. No fungus was isolated from water-inoculated tissues of control plants and healthy trees. Identity was confirmed by analysis of the rDNA internal transcribed spacer region (ITS1-5.8S-ITS2) with primers ITS1 and ITS4. BLAST searches showed 99% identity with Botryosphaeria dothidea isolates from GenBank (Accession Nos. HQ660454 and FJ790846). Representative sequences of B. dothidea from H. chinensis from China have been deposited in GenBank (Accession No. JQ766122). On the basis of morphological and molecular results, the fungus isolated from diseased H. chinensis was confirmed to be B. dothidea. Pathogenicity tests were conducted by stem inoculation of 1-year-old H. chinensis seedlings. Mycelial plugs (3 to 4 mm in diameter) of B. dothidea from actively growing colonies were applied to same-sized bark wounds on the middle point of the stems. Control seedlings were inoculated with sterile PDA plugs. Inoculated and control seedlings (three each) were kept in a greenhouse and watered as needed. After 4 weeks, all H. chinensis seedlings developed vascular tissue discoloration and leaf wilting; no such symptoms were manifested by seedlings in the control treatment. B. dothidea was reisolated from all B. dothidea-inoculated, symptomatic tissues, fulfilling Koch's postulates. In China, B. dothidea has previously been reported to cause canker and dieback disease of Eucalyptus grandis (2) and gummosis of peach (1); however, to our knowledge, this is the first report of B. dothidea causing canker and dieback on H. chinensis. References: (1) Y. Ko et al. Plant Pathol. Bull. 1:70, 1992. (2) L. Yu et al. Plant Dis. 93:764, 2009.

Toxicodynamics of rigid polystyrene microparticles on pulmonary gas exchange in mice: implications for microemboli-based drug delivery systems

The toxicodynamic relationship between the number and size of pulmonary microemboli resulting from uniformly sized, rigid polystyrene microparticles (MPs) administered intravenously and their potential effects on pulmonary gas exchange were investigated. CD-1 male mice (6-8 weeks) were intravenously administered 10, 25 and 45 μm diameter MPs. Oxygen hemoglobin saturation in the blood (SpO(2)) was measured non-invasively using a pulse oximeter while varying inhaled oxygen concentration (F(I)O(2)). The resulting data were fit to a physiologically based non-linear mathematical model that estimates 2 parameters: ventilation-perfusion ratio (V(A)/Q) and shunt (percentage of deoxygenated blood returning to systemic circulation). The number of MPs administered prior to a statistically significant reduction in normalized V(A)/Q was dependent on particle size. MP doses that resulted in a significant reduction in normalized V(A)/Q one day post-treatment were 4000, 40,000 and 550,000 MPs/g for 45, 25 and 10 μm MPs, respectively. The model estimated V(A)/Q and shunt returned to baseline levels 7 days post-treatment. Measuring SpO(2) alone was not sufficient to observe changes in gas exchange; however, when combined with model-derived V(A)/Q and shunt early reversible toxicity from pulmonary microemboli was detected suggesting that the model and physical measurements are both required for assessing toxicity. Moreover, it appears that the MP load required to alter gas exchange in a mouse prior to lethality is significantly higher than the anticipated required MP dose for effective drug delivery. Overall, the current results indicate that the microemboli-based approach for targeted pulmonary drug delivery is potentially safe and should be further explored.

C60:LiF nanocomposite for high power efficiency fluorescent organic light-emitting diodes

To reduce the driving voltage, and hence enhance the power efficiency of OLEDs, the mobility of the various carrier transport layers needs to be increased. Buckminsterfullerene (C(60)) has been proposed to be one possible alternative conductive electron transport layer (ETL) to enhance the power efficiency in OLEDs, due to its high conductivity and the formation of an ohmic contact with the LiF/Al cathode. The optical properties of a nanocomposite of C(60) with LiF (C(60):LiF) and its potential as an efficient ETL in OLEDs was studied. With proper optimization of the device structure, a more than 50% improvement in the power efficiency, without sacrificing the high EQE, in optimized fluorescent OLEDs with the use of C(60):LiF nanocomposite ETL was achieved.

Characterization of the phenotype of high collagen-producing fibroblast clones in systemic sclerosis, using a new modified limiting-dilution method

BACKGROUND

Overproduction of type I collagen in fibroblasts of systemic sclerosis (SSc) is the hallmark of fibrosis. Establishment and characterization of the phenotype of SSc fibroblasts has been hindered by the heterogeneity between fibroblasts and the lack of adequate cloning methods.

AIM

To establish and investigate the characteristics of the SSc high collagen-producing fibroblast phenotype.

METHODS

Primary cultured fibroblasts from skin biopsies of patients with SSc and normal controls were cloned by a new modified limiting-dilution method. All clones were divided into different subpopulations based on their α1(I) procollagen (COL1A1) mRNA level detected by real-time reverse transcriptase PCR assay. In the different subpopulations, cell growth and cycle distribution were analysed by MTT and flow cytometry, COL1A1 promoter activity was examined by transient transfection, and the binding activity of Sp1 to the COL1A1 proximal promoter was investigated by quantitative chromatin immunoprecipitation.

RESULTS

The clonogenicities of SSc and normal control fibroblasts were similar, but the mean COL1A1 mRNA level of clones and the percentage of the subpopulation with a high COL1A1 mRNA level were significantly higher in SSc fibroblasts than in controls. There was no significant difference on cell growth and cycle between different subpopulations of SSc and control fibroblasts. The COL1A1 proximal promoter activity and its binding activity to Sp1 in the clones were strongly correlated with their COL1A1 mRNA level.

CONCLUSION

Overproduction of collagen in an SSc fibroblast subpopulation seems to result mainly from the abnormally activated transcription of COL1A1 rather than from overproliferation of fibroblasts. The new modified limiting-dilution method provides a useful means for characterizing cells with heterogeneous phenotypes.

Multidose pharmacokinetics of orally administered florfenicol in the channel catfish (Ictalurus punctatus)

Plasma disposition of florfenicol in channel catfish was investigated after an oral multidose (10 mg/kg for 10 days) administration in freshwater at water temperatures ranging from 24.7 to 25.9 °C. Florfenicol concentrations in plasma were analyzed by means of liquid chromatography with MS/MS detection. After the administration of florfenicol, the mean terminal half-life (t(1/2)), maximum concentration at steady-state (Css (max)), time of Css (max) (T(max)), minimal concentration at steady-state (Css (min)), and Vc /F were 9.0 h, 9.72 μg/mL, 8 h, 2.53 μg/mL, and 0.653 L/kg, respectively. These results suggest that florfenicol administered orally at 10 mg/kg body weight for 10 days could be expected to control catfish bacterial pathogens inhibited in vitro by a minimal inhibitory concentration value of <2.5 μg/mL.

Intermediate-conductance Ca(2+) -activated potassium and volume-sensitive chloride channels in endothelial progenitor cells from rat bone marrow mononuclear cells

AIM

Bone marrow endothelial progenitor cells (BMEPCs) are believed to be a promising cell source for regenerative medicine; however, their electrophysiology properties have not been fully clarified, which is important to the clinical application of BMEPCs. The current study was designed to determine the transmembrane ion currents and mRNA expression levels of related ion channel subunits in rat BMEPCs.

METHODS

Bone marrow mononuclear cells were isolated by density gradient separation and cultured in EPC medium. The transmembrane ion currents were determined using whole-cell patch-voltage clamp technique, and the levels of mRNA and protein expressions of functional ionic channels were measured using RT-PCR and western immunoblot analysis.

RESULTS

We observed two types of ionic currents in undifferentiated rat BMEPCs. One was Ca(2+) -activated potassium current (I(kca) ), which was seen in approx. 90% of cells when 1 μm Ca(2+) was employed in pipette solution, and it was predominantly inhibited by intermediate-conductance I(kca) inhibitor clotrimazole. The other one was volume-sensitive chloride current (I(cl) ), which was detected in 85.7% of cells when BMEPCs were subjected to K(+) -free hypotonic extracellular solution, whose currents could be inhibited by 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). The corresponding ion channel genes and proteins, KCNN4 for I(kca) and Clcn3 for I(cl) , were confirmed by RT-PCR and western immunoblot analysis of BMEPCs.

CONCLUSION

Our results demonstrated for the first time that rat BMEPCs expressed intermediate-conductance Ca(2+) -activated potassium currents and volume-sensitive chloride currents, and corresponding genes and proteins of these two channels are KCNN4 and Clcn3 respectively.

Integrated genomic analyses identify WEE1 as a critical mediator of cell fate and a novel therapeutic target in acute myeloid leukemia

Acute myeloid leukemia (AML) remains a therapeutic challenge despite increasing knowledge about the molecular origins of the disease, as the mechanisms of AML cell escape from chemotherapy remain poorly defined. We hypothesized that AML cells are addicted to molecular pathways in the context of chemotherapy and used complementary approaches to identify these addictions. Using novel molecular and computational approaches, we performed genome-wide shRNA screens to identify proteins that mediate AML cell fate after cytarabine exposure, gene expression profiling of AML cells exposed to cytarabine to identify genes with induced expression in this context, and examination of existing gene expression data from primary patient samples. The integration of these independent analyses strongly implicates cell cycle checkpoint proteins, particularly WEE1, as critical mediators of AML cell survival after cytarabine exposure. Knockdown of WEE1 in a secondary screen confirmed its role in AML cell survival. Pharmacologic inhibition of WEE1 in AML cell lines and primary cells is synergistic with cytarabine. Further experiments demonstrate that inhibition of WEE1 prevents S-phase arrest induced by cytarabine, broadening the functions of WEE1 that may be exploited therapeutically. These data highlight the power of integrating functional and descriptive genomics, and identify WEE1 as potential therapeutic target in AML.

Aliskiren vs. angiotensin receptor blockers in hypertension: meta-analysis of randomized controlled trials

BACKGROUND

Aliskiren, a newly discovered renin inhibitor, blocks the renin-angiotensin system (RAS) from the top of the enzyme cascade and therefore, might provide comparable or even superior clinical efficacy of blood pressure (BP) control than angiotensin receptor blockers (ARBs). With this meta-analysis, we aimed to compare the efficacy and tolerability of aliskiren and ARBs in the treatment of hypertension in the short-term treatment period.

METHODS

Reports of randomized controlled trials (RCTs) comparing aliskiren and ARBs in patients with hypertension were selected by a search of the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. The main outcome measures were reduction in diastolic BP (DBP) and systolic BP (SBP) and rates of therapeutic response and BP control. We also compared the tolerability of aliskiren and ARBs. Revman v5.0 was used to obtain the pooled estimates.

RESULTS

We analyzed data from 10 reports of trials involving 3,732 participants. DBP and SBP reduction did not differ between aliskiren and ARBs (weighted mean difference (WMD), -0.18; 95% confidence interval (CI), -1.07 to 0.71, and WMD, 0.15; 95% CI, -1.38 to 1.69, respectively). Aliskiren and ARB treatment did not differ in rates of BP control or therapeutic response. Moreover, aliskiren and ARB treatment led to a similar number of adverse events, severe adverse events, and withdrawal due to adverse events.

CONCLUSION

Aliskiren is as effective as ARBs (losartan, valsartan, and irbesartan) in controlling BP and does not differ from ARBs in risk of adverse events.

Enhanced ZAG production by subcutaneous adipose tissue is linked to weight loss in gastrointestinal cancer patients

Background:

Profound loss of adipose tissue is a hallmark of cancer cachexia. Zinc-α2-glycoprotein (ZAG), a recently identified adipokine, is suggested as a candidate in lipid catabolism.

Methods:

In the first study, eight weight-stable and 17 cachectic cancer patients (weight loss ⩾5% in previous 6 months) were recruited. Zinc-α2-glycoprotein mRNA and protein expression were assessed in subcutaneous adipose tissue (SAT), subcutaneous adipose tissue morphology was examined and serum ZAG concentrations were quantified. In the second cohort, ZAG release by SAT was determined in 18 weight-stable and 15 cachectic cancer patients. The effect of ZAG on lipolysis was evaluated in vitro.

Results:

Subcutaneous adipose tissue remodelling in cancer cachexia was evident through shrunken adipocytes with increased fibrosis. In cachectic cancer patients, ZAG mRNA was upregulated (2.7-fold, P=0.028) while leptin mRNA decreased (2.2-fold, P=0.018); serum ZAG levels were found to be unaffected. Zinc-α2-glycoprotein mRNA correlated positively with weight loss (r=0.51, P=0.01) and serum glycerol levels (r=0.57, P=0.003). Zinc-α2-glycoprotein release by SAT was also elevated in cachectic patients (1.5-fold, P=0.024) and correlated with weight loss (r=0.50, P=0.003). Recombinant ZAG stimulated lipolysis in human adipocytes.

Conclusions:

Zinc-α2-glycoprotein expression and secretion by adipose tissue is enhanced in cachectic cancer patients. Given its lipid-mobilising effect, ZAG may contribute to adipose atrophy associated with cancer cachexia in human beings.

Macrophage-secreted factors inhibit ZAG expression and secretion by human adipocytes

Zinc-alpha2-glycoprotein (ZAG), a novel adipokine, is downregulated in adipose tissue in obesity, a state characterized by increased adipose tissue macrophage infiltration and chronic low-grade inflammation. This study investigated whether macrophage-secreted factors and TNF-alpha, a major product of macrophages, modulate ZAG expression and secretion by human adipocytes. ZAG was produced primarily by adipocytes, and not by preadipocytes and macrophages. Incubation of preadipocytes with macrophage-conditioned medium for up to 12 days decreased ZAG mRNA and protein release, and the expression of adipogenic markers (PPARgamma and C/EBPalpha). Adipocytes treated with macrophage-conditioned medium for 24h displayed significant reductions in ZAG mRNA and release. Chronic TNF-alpha treatment let to significant decreases in ZAG expression and secretion, but marked upregulation of pro-inflammatory cytokines and chemokines (IL-6, leptin, IL-8, MCP-1 and RANTES) in adipocytes. These findings suggest that macrophage-associated inflammation may play a significant role in the downregulation of ZAG in adipose tissue in obesity.

Downregulation of zinc-{alpha}2-glycoprotein in adipose tissue and liver of obese ob/ob mice and by tumour necrosis factor-alpha in adipocytes

Zinc-alpha2-glycoprotein (ZAG, also listed as AZGP1 in the MGI Database), a lipid-mobilising factor, has recently been suggested as a potential candidate in the modulation of body weight. We investigated the effect of increased adiposity on ZAG expression in adipose tissue and the liver and on plasma levels in obese (ob/ob) mice compared with lean siblings. The study also examined the effect of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNFalpha) on ZAG expression in adipocytes. Zag mRNA levels were significantly reduced in subcutaneous (fourfold) and epididymal (eightfold) fat of ob/ob mice. Consistently, ZAG protein content was decreased in both fat depots of ob/ob mice. In the liver of obese animals, steatosis was accompanied by the fall of both Zag mRNA (twofold) and ZAG protein content (2.5-fold). Plasma ZAG levels were also decreased in obese mice. In addition, Zag mRNA was reduced in epididymal (fivefold) and retroperitoneal (fivefold) adipose tissue of obese (fa/fa) Zucker rats. In contrast to Zag expression, Tnfalpha mRNA levels were elevated in adipose tissue (twofold) and the liver (2.5-fold) of ob/ob mice. Treatment with TNFalpha reduced Zag gene expression in differentiated adipocytes, and this inhibition was chronic, occurring at 24 and 48 h following TNFalpha treatment. It is concluded that ZAG synthesis in adipose tissue and the liver is downregulated, as are its circulating levels, in ob/ob mice. The reduced ZAG production may advance the susceptibility to lipid accumulation in these tissues in obesity, and this could be at least in part attributable to the inhibitory effect of TNFalpha.