Multiple target-specific molecular imaging agents detect liver cancer in a preclinical model

Liver cancer is the fifth most common cause of cancer deaths worldwide. Noninvasive diagnosis is difficult and the disease heterogeneity reduces the accuracy of pathological assays. Improvement in diagnostic imaging of specific molecular disease markers has provided hope for accurate and early noninvasive detection of liver cancer. However, all current imaging technologies, including ultrasonography, computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging, are not specific targets for detection of liver cancer. The aim of this study was to test the feasibility of injecting a cocktail of specific molecular imaging agents to noninvasively image liver cancer. The target-specific cocktail contained agents for imaging the neovasculature (RGD peptide), matrix metalloproteinase (MMP), and glucose transport (¹⁸F-fluorodeoxyglucose [¹⁸F-FDG]). Imaging studies were performed in liver cancer cells and xenograft models. The distribution of MMP at the intracellular level was imaged by confocal microscopy. RGD, MMP, and ¹⁸F-FDG were imaged on tumor-bearing mice using PET, CT, X-ray, and multi-wavelength optical imaging modalities. Image data demonstrated that each agent bound to a specific disease target component. The same liver cancer xenograft contained multiple disease markers. Those disease markers were heterogenetically distributed in the same tumor nodule. The molecular imaging agents had different distributions in the whole body and inside the tumor nodule. All target-specific agents yielded high tumor-to-background ratios after injection. In conclusion, target-specific molecular imaging agents can be used to study liver cancer in vitro and in vivo. Noninvasive multimodal/multi-target-specific molecular imaging agents could provide tools to simultaneously study multiple liver cancer components.

siRNA silencing of gene expression in trabecular meshwork: RhoA siRNA reduces IOP in mice

Few reports described efficient transfection in the trabecular meshwork (TM) in vivo. In the present study, we investigated the distribution of cy3-labeled siRNAs after giving injection into the anterior chamber (AC) and explored the use of RhoA siRNA (siRhoA) to modulate intraocular pressure (IOP) through downregulation of RhoA gene and protein expression. Cy3-labeled siRNAs were injected into the AC to investigate the distribution. In addition, siRhoA was applied to normal and DEX-induced elevated IOP mice. The RhoA gene was detected at 1d post-injection (PI) using real-time RT-PCR. Proteins were examined using immunofluorescence staining at 1, 2, and 3 day PI. IOP was measured pre- and post-injection using a TONOPEN. Toxicity was preliminarily assessed using clinical observation and hematoxylin-eosin staining. The study demonstrated that cy3-labeled siRNAs accumulated in mouse TM in a dose-dependent manner, with a peak at 24h PI. There was no visible siRNA fluorescence in the corneal endothelium, and little in the iris. siRhoA caused large decreases in RhoA mRNA and protein expression in mouse TM (p < 0.01). In normal mice, injections of siRhoA induced decreases in IOP, by 2d, with recovery to baseline by 3d PI. For DEX-treated animals, IOP significantly decreased from 2d to 5d PI (p < 0.05). There was no obvious toxicity after the siRhoA application. These results suggest that (1) siRNA injection into the AC leads to transient gene transfection in TM; (2) inhibiting RhoA expression in TM with siRNA is effective in suppressing elevated IOP in mice, suggesting that siRhoA is a potential pharmaceutical intervention for glaucoma.

From understanding the development landscape of the canonical fate-switch pair to constructing a dynamic landscape for two-step neural differentiation

Recent progress in stem cell biology, notably cell fate conversion, calls for novel theoretical understanding for cell differentiation. The existing qualitative concept of Waddington’s “epigenetic landscape” has attracted particular attention because it captures subsequent fate decision points, thus manifesting the hierarchical (“tree-like”) nature of cell fate diversification. Here, we generalized a recent work and explored such a developmental landscape for a two-gene fate decision circuit by integrating the underlying probability landscapes with different parameters (corresponding to distinct developmental stages). The change of entropy production rate along the parameter changes indicates which parameter changes can represent a normal developmental process while other parameters’ change can not. The transdifferentiation paths over the landscape under certain conditions reveal the possibility of a direct and reversible phenotypic conversion. As the intensity of noise increases, we found that the landscape becomes flatter and the dominant paths more straight, implying the importance of biological noise processing mechanism in development and reprogramming. We further extended the landscape of the one-step fate decision to that for two-step decisions in central nervous system (CNS) differentiation. A minimal network and dynamic model for CNS differentiation was firstly constructed where two three-gene motifs are coupled. We then implemented the SDEs (Stochastic Differentiation Equations) simulation for the validity of the network and model. By integrating the two landscapes for the two switch gene pairs, we constructed the two-step development landscape for CNS differentiation. Our work provides new insights into cellular differentiation and important clues for better reprogramming strategies.

Effects of dietary arginine levels and carbohydrate-to-lipid ratios on mRNA expression of growth-related hormones in largemouth bass, Micropterus salmoides

Utilizing the tissue samples and growth data collected from our two preceding researches in largemouth bass (LMB), we have investigated effects of dietary arginine (Arg) levels and carbohydrate-to-lipid (CHO/LIP) ratios on the GH, IGF-I and insulin expression in related tissues to find possible relationships between the nutrient intake, growth performance and transcript level. Hepatic IGF-I and pituitary GH mRNA levels were significantly up-regulated by lower dietary Arg levels from 1.94% to 3.01% and by higher levels from 2.76% to 3.01%, respectively, while Brockmann body (BB)-containing tissue insulin mRNA expression was not affected. Dietary CHO/LIP ratios ranging from 0.32 to 5.17 (w/w) affected pituitary GH, liver IGF-I and BB-containing tissue insulin mRNA expression in a ratio-specific pattern. The lower ratios from 0.32 to 2.36 significantly up-regulated GH and insulin transcript levels, but significantly down-regulated IGF-I transcript levels; the higher ratios did no longer exert any further effects on them. Meanwhile, two strong positive correlations (r=0.892, r=0.885) between hepatic IGF-I transcript levels and specific growth rates of tested fish were observed with varying dietary Arg levels and CHO/LIP ratios, respectively. These findings indicate that in LMB dietary Arg levels and CHO/LIP ratios regulate differentially the endocrine system of GH, IGF-I and insulin at transcription level; this system, in turn, plays a fundamental role in the regulation of the nutrient metabolism and somatic growth; and that hepatic IGF-I mRNA abundance should be a more reliable index to assess growth and nutritional fitness than the others, at least in LMB.

Identification of Wnt pathway, uPA, PAI-1, MT1-MMP, S100A4 and CXCR4 associated with enhanced metastasis of human large cell lung cancer by DNA microarray

AIM

The aim of this paper was to investigate the differentially expressed genes in large cell lung cancer cell lines with different metastatic potential, and to screen out new candidate genes related to metastasis of lung cancer.

METHODS

The total RNAs of low and high metastatic large cell lung cancer cell lines (NL9980 and L9981) were extracted and processed, then hybridized to Affymetrix HG U133 Plus 2.0 array. The hybridization signals were scanned and compared to find out the differentially expressed genes. Chosen genes were verified by Western Blot. Bioinformatics were used to analyze the functions and related pathways of the genes.

RESULTS

There were 933 differentially expressed genes between NL9980 and L9981 cell lines. In the high metastatic cell line L9981, 672 genes were up-regulated and 260 genes were down-regulated compared with the low metastatic cell line NL9980. The differentially expressed genes were mainly associated with binding, catalytic activity, signal transducer activity and transporter activity, and mainly involved in pathways including, pathways in cancer, focal adhesion, regulation of actin cytoskeleton, ECM-receptor interaction.

CONCLUSION

Differentially expressed genes with the functions including binding, catalytic activity, signal transducer activity and transporter activity may promote metastasis of lung cancer cells through complicated networks including Wnt pathway and metastasis-related genes such as uPA, PAI-1, MT1-MMP, S100A4 and CXCR4.

Improved measurement of muon antineutrino disappearance in MINOS

We report an improved measurement of ν(μ) disappearance over a distance of 735 km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a ν(μ)-enhanced configuration. From a total exposure of 2.95×10(20) protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of Δm2=[2.62(-0.28)(+0.31)(stat)±0.09(syst)]×10(-3)  eV2 and constrain the ν(μ) mixing angle sin2(2θ)>0.75 (90% C.L.). These values are in agreement with Δm2 and sin2(2θ) measured for ν(μ), removing the tension reported in [P. Adamson et al. (MINOS), Phys. Rev. Lett. 107, 021801 (2011).].

MTSS1, a novel target of DNA methyltransferase 3B, functions as a tumor suppressor in hepatocellular carcinoma

DNA methyltransferase 3B (DNMT3B) mediates gene silencing via epigenetic mechanisms during hepatocellular carcinoma (HCC) progression. We aimed to identify novel targets of DNMT3B and their potential regulatory mechanisms in HCC. Metastasis suppressor 1 (MTSS1) was one of the DNMT3B targets and selected for further study. DNMT3B overexpression was detected in 81.25% of clinical HCC specimens and was negatively associated with MTSS1 in HCC cells and clinical samples. The underlying mechanism by which DNMT3B silences MTSS1 was studied using a combination of methylation-specific polymerase chain reaction (PCR) and bisulfite genome sequencing, chromatin immunoprecipitation-PCR and luciferase reporter assays. We found that the MTSS1 promoter region was sparsely methylated, and the methylation inhibitors failed to abolish DNMT3B-mediated MTSS1 silencing. DNMT3B protein bound directly to the 5'-flanking region (-865/-645) of the MTSS1 gene to inhibit its transcription. The functional role of MTSS1 was investigated using in vitro and in vivo tumorigenicity assays. As a result, MTSS1 exerted tumor suppressor effects and arrested cells in the G2/M phase, but not the G1/S phase of the cell cycle when it was depleted or overexpressed in HCC cells. Taken together, MTSS1, a novel target of DNMT3B, is repressed by DNMT3B via a DNA methylation-independent mechanism. MTSS1 was further characterized as a novel tumor suppressor gene in HCC. These findings highlight how DNMT3B regulates MTSS1, and such data may be useful for the development of new treatment options for HCC.

Neurotrophic effect of bone marrow mesenchymal stem cells for erectile dysfunction in diabetic rats

It has been demonstrated that intracavernous injection of bone marrow-derived mesenchymal stem cells (BM-MSCs) had beneficial effects on improving erectile function in type-1 diabetic rats. This study was designed to investigate the neurotrophic effect of BM-MSCs for type-1 diabetic rats. Streptozocin-induced type-1 diabetic rats were randomly divided into three groups: diabetic group, BM-MSCs-treated group and BM-MSCs-conditioned medium-treated group. At the 3d, 1 and 2w time points after BM-MSCs injection, three randomly selected rats in MSCs group were sacrificed and penile samples were harvested to detect BM-MSCs in penile tissue. Four weeks after intracavernous injection of BM-MSCs or BM-MSCs-conditioned medium, intracavernous pressure (ICP) was assessed to evaluate the erectile function. Immunohistochemistry was used to track labelled BM-MSCs in penile tissue and to detect neuronal nitric oxide synthase (nNOS) and neurofilament (NF) positive fibres in penile dorsal nerve. Enzyme lined immunosorbent assay (ELISA) was used to measure the concentrations of vascular endothelial growth factor (VEGF), nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in BM-MSCs-conditioned medium. BM- MSCs secreted detectable levels of VEGF, BDNF and NGF. Intracavernous injection of BM-MSCs improved erectile function in diabetic rats. The functional improvement was accompanied by promoted nNOS and NF positive nerve fibres within penile dorsal nerve in type-1 diabetic rats. Histological data revealed a time-dependent decrease in the number of BM-MSCs in the corpus cavernosum following injection. Furthermore, the beneficial effect of BM-MSCs was partially repeated by BM-MSCs-conditioned medium. Intracavernous injection of BM-MSCs is effective in improving nerve regeneration in diabetic rats. Paracrine effects of BM-MSCs are probably involved in the improvement.

Recent developments of peptidomimetic HIV-1 protease inhibitors

HIV protease plays a crucial role in the viral life cycle by processing the viral Gag and Gag-Pol polyproteins into structural and functional proteins essential for viral maturation. Inhibition of HIV-1 protease leads to the production of noninfectious virus particles and hence is an important therapeutic target for antiviral therapy in AIDS patients. Among many strategies to combat this disease, highly active antiretroviral therapy (HAART) with HIV protease inhibitors (PIs) in combination with reverse transcriptase inhibitors and fusion inhibitor continues to be the first line treatment for control of HIV infection. However, the rapid emergence of drug-resistant HIV-1 strains and the appearance of cross-resistance are severely limiting the long-term treatment options. Thus, numerous efforts have been made in the design and synthesis of novel protease inhibitors with broad-spectrum activity against multidrug-resistant HIV-1 variants by medicinal chemists. This review will focus on the substrate-based drug design of novel peptidomimetic PIs in recent years since 2006.

A transcriptional dynamic network during Arabidopsis thaliana pollen development

Background

To understand transcriptional regulatory networks (TRNs), especially the coordinated dynamic regulation between transcription factors (TFs) and their corresponding target genes during development, computational approaches would represent significant advances in the genome-wide expression analysis. The major challenges for the experiments include monitoring the time-specific TFs' activities and identifying the dynamic regulatory relationships between TFs and their target genes, both of which are currently not yet available at the large scale. However, various methods have been proposed to computationally estimate those activities and regulations. During the past decade, significant progresses have been made towards understanding pollen development at each development stage under the molecular level, yet the regulatory mechanisms that control the dynamic pollen development processes remain largely unknown. Here, we adopt Networks Component Analysis (NCA) to identify TF activities over time couse, and infer their regulatory relationships based on the coexpression of TFs and their target genes during pollen development.

Results

We carried out meta-analysis by integrating several sets of gene expression data related to Arabidopsis thaliana pollen development (stages range from UNM, BCP, TCP, HP to 0.5 hr pollen tube and 4 hr pollen tube). We constructed a regulatory network, including 19 TFs, 101 target genes and 319 regulatory interactions. The computationally estimated TF activities were well correlated to their coordinated genes' expressions during the development process. We clustered the expression of their target genes in the context of regulatory influences, and inferred new regulatory relationships between those TFs and their target genes, such as transcription factor WRKY34, which was identified that specifically expressed in pollen, and regulated several new target genes. Our finding facilitates the interpretation of the expression patterns with more biological relevancy, since the clusters corresponding to the activity of specific TF or the combination of TFs suggest the coordinated regulation of TFs to their target genes.

Conclusions

Through integrating different resources, we constructed a dynamic regulatory network of Arabidopsis thaliana during pollen development with gene coexpression and NCA. The network illustrated the relationships between the TFs' activities and their target genes' expression, as well as the interactions between TFs, which provide new insight into the molecular mechanisms that control the pollen development.

Point-of-care oral-based diagnostics

Many of the target molecules that reside in blood are also present in oral fluids, albeit at lower concentrations. Oral fluids are, however, relatively easy and safe to collect without the need for specialized equipment and training. Thus, oral fluids provide convenient samples for medical diagnostics. Recent advances in lab-on-a-chip technologies have made minute, fully integrated diagnostic systems practical for an assortment of point-of-care tests. Such systems can perform either immunoassays or molecular diagnostics outside centralized laboratories within time periods ranging from minutes to an hour. The article briefly reviews recent advances in devices for point-of-care testing with a focus on work that has been carried out by the authors as part of a NIH program.

Improved search for Muon-neutrino to electron-neutrino oscillations in MINOS

We report the results of a search for ν(e) appearance in a ν(μ) beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 × 10(20) protons on the NuMI target at Fermilab, we find that 2 sin(2) (θ(23))sin(2)(2θ(13))<0.12(0.20) at 90% confidence level for δ = 0 and the normal (inverted) neutrino mass hierarchy, with a best-fit of 2sin(2) (θ(23))sin(2)(2θ(13)) = 0.041(-0.031)(+0.047) (0.079(-0.053) (+0.071)). The θ(13) = 0 hypothesis is disfavored by the MINOS data at the 89% confidence level.

Histone modifications and methyl-CpG-binding domain protein levels at the TNFSF7 (CD70) promoter in SLE CD4+ T cells

Abstract: In systemic lupus erythematosus (SLE), T lymphocytes overexpress CD70 ( TNFSF7 gene), leading to the synthesis of autoreactive IgGs. CD70 upregulation in SLE CD4+ T cells is associated with hypomethylation of TNFSF7 promoter. In this study, we explored histone modifications in the TNFSF7 promoter region in SLE CD4+ T cells, and characterized the effects of a DNA methyltransferase inhibitor (5-azaC) and a histone deacetylase inhibitor (TSA) on CD70 expression. We found that CD70 mRNA was significantly increased in active lupus CD4+ T cells, and in control cells treated with 5-azaC, TSA, or both. Histone H3 acetylation and dimethylated H3 lysine 4 (H3K4me2) levels were significantly elevated in patients with lupus, and both factors correlated positively with disease activity. MeCP2 protein levels within the TNFSF7 promoter decreased in patients with active lupus. Treatment of CD4+ T cells with 5-azaC alone significantly raised H3K4 dimethyl levels at the TNFSF7 locus. TSA treatment significantly increased H3 and H4 acetylation levels, as well as levels of H3K4 dimethylation at the TNFSF7 locus. Treatment with 5-azaC plus TSA enhanced H3 acetylation levels. These findings indicate that aberrant histone modifications within the TNFSF7 promoter may contribute to the development of lupus by increasing CD70 expression in CD4+ T cells.

Tracking intracavernously injected adipose-derived stem cells to bone marrow

Intracavernous (IC) injection of stem cells (SCs) has been shown to improve erectile function in various erectile dysfunction (ED) animal models. However, the tissue distribution of the injected cells remains unknown. In this study we tracked IC injected adipose-derived stem cells (ADSCs) in various tissues. Rat paratesticular fat was processed for ADSC isolation and culture. The animals were then subject to cavernous nerve (CN) crush injury or sham operation, followed by IC injection of one million autologous or allogeneic ADSCs that were labeled with 5-ethynyl-2-deoxyuridine (EdU). Another group of rats received IC injection of EdU-labeled allogeneic penile smooth muscle cells (PSMCs). At 2 and 7 days post-injection, penises and femoral bone marrow were processed for histological analyses. Whole femoral bone marrows were also analyzed for EdU-positive cells by flow cytometry. The results show that ADSCs exited the penis within days of IC injection and migrated preferentially to bone marrow. Allogenicity did not affect ADSC's bone marrow appearance either at 2 or 7 days, while CN injury reduced the number of ADSCs in bone marrow significantly at 7 but not 2 days. The significance of these results in relation to SC therapy for ED is discussed.

First direct observation of muon antineutrino disappearance

This Letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for ν(μ) production, accumulating an exposure of 1.71 × 10²⁰ protons on target. In the Far Detector, 97 charged current ν(μ) events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3σ. The best fit to oscillation yields |Δm²| = [3.36(-0.40)(+0.46)(stat) ± 0.06(syst)] × 10⁻³ eV², sin²(2θ) = 0.86(-0.12)(+0.11)(stat) ± 0.01(syst). The MINOS ν(μ) and ν(μ) measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters.

Active to sterile neutrino mixing limits from neutral-current interactions in MINOS

Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07×10(20) protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754 ± 28(stat) ± 37(syst) for oscillations among three active flavors. The fraction f(s) of disappearing ν(μ) that may transition to ν(s) is found to be less than 22% at the 90% C.L.

Measurement of the neutrino mass splitting and flavor mixing by MINOS

Measurements of neutrino oscillations using the disappearance of muon neutrinos from the Fermilab NuMI neutrino beam as observed by the two MINOS detectors are reported. New analysis methods have been applied to an enlarged data sample from an exposure of 7.25×10(20) protons on target. A fit to neutrino oscillations yields values of |Δm(2)|=(2.32(-0.08)(+0.12))×10(-3) eV(2) for the atmospheric mass splitting and sin(2)(2θ)>0.90 (90% C.L.) for the mixing angle. Pure neutrino decay and quantum decoherence hypotheses are excluded at 7 and 9 standard deviations, respectively.

Results from a low-energy analysis of the CDMS II germanium data

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10  GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9  GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

Persistence of psychosine in brain lipid rafts is a limiting factor in the therapeutic recovery of a mouse model for Krabbe disease

Sphingolipids are intrinsic components of membrane lipid rafts. The abnormal accumulation of these molecules may introduce architectural and functional changes in these domains, leading to cellular dysfunction. Galactosylsphingosine (psychosine) is a pathogenic lipid raft-associated molecule whose accumulation leads to brain deterioration and irreversible neurological handicap in the incurable leukodystrophy Krabbe disease (KD). The relevance of clearing excessive levels of pathogenic psychosine from lipid rafts in therapy for KD has not been investigated. The work presented here demonstrates that psychosine inhibits raft-mediated endocytosis in neural cells. In addition, although in vitro enzyme reconstitution is sufficient for the reversal of related endocytic defects in affected neural cells, traditional in vivo enzyme therapies in the mouse model of KD appear to be insufficient for complete removal of pathogenic levels of raft-associated psychosine. This work describes a mechanism that may contribute to limiting the in vivo efficacy of traditional therapies for KD.