Targeted delivery of siRNA-generating DNA nanocassettes using multifunctional nanoparticles

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double-stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double-stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor-mediated internalization should enhance the therapeutic effect of the siRNA-mediated cancer therapy.

Trends of hypertension prevalence, awareness, treatment and control in rural areas of northern China during 1991-2011

This study aims to investigate the trends in prevalence, awareness, treatment and control of hypertension among rural residents aged 35-74 years in northern China during the country's rapid economic development from 1991 to 2011. Two surveys, conducted in 1991 and 2011, included 2196 and 1939 participants aged 35-74 years from same villages in Ji County, Tianjin of China, respectively. The prevalence of hypertension, adjusted by age and gender using the world standard population in 2000, increased 30% (39.9% vs 51.7%) between 1991 and 2011. The increase was greatest (68%) in women aged 35-44 years. Meanwhile, the prevalence of stage II hypertension increased by 75% overall, with a 4-fold increase in men aged 45-54 years. Although the awareness, treatment and control of hypertension increased significantly during the same period, they remained unacceptably poor. In conclusion, the community-based surveys showed that the prevalence of hypertension in rural residents of northern China aged 35-74 years increased rapidly over the past 20 years, and most dramatically in young women. Efforts in the primary prevention of hypertension, particularly for young women, and promoting education for hypertension awareness, treatment and control are of paramount importance in rural China.

Oxidative stress and DNA damage in utero and embryo implantation of mice exposed to carbon disulfide at peri-implantation

Carbon disulfide (CS2) has reproductive toxicity but the mechanism remains unclear. The aim of the present study was to investigate the effect of oxidative stress and DNA damage on embryo implantation of mice exposed to CS2 at peri-implantation. CS2 exposure was on gestational day 3 (GD3), GD4, GD5 and GD6, separately, and the number of embryonic day 9 (E9) mouse embryos was obtained. DNA damage of endometrial cells, oxidative stress and 8-hydroxy-2′-deoxyguanosine (8-OH-dG) level in uterus tissues were tested with time series at different end points after exposure. The number of E9 mouse embryos significantly decreased in all CS2 exposure groups, especially on GD4 exposure. The rates of embryo implantation decreased by 43.05%, 63.74%, 60.45% and 47.26% for CS2 exposure on GD3, GD4, GD5 and GD6, respectively. Oxidative stress significantly increased within 24 h and reached the top level at 18 h after exposure. The same time-dependent trend was observed no matter when the exposure happened at peri-implantation. 8-OH-dG significantly increased at 18 h and 24 h after exposure by 893.8% and 647.4%, respectively, when compared with the control. The indexes of DNA damage significantly increased at 6 h after exposure, which appeared earlier than the changes of oxidative stress and 8-OH-dG. Besides, both oxidative stress and DNA damage showed a strong negative correlation with the number of E9 mouse embryos. The present study illustrated that CS2 directly induced DNA damage in endometrial cells and enhanced the action through oxidative stress, both of which were responsible for CS2-induced embryo loss.

Response to dietary L-glutamine supplementation in weaned piglets: a serum metabolomic comparison and hepatic metabolic regulation analysis

A novel metabolomic method based on gas chromatography-mass spectrometry was applied to investigate serum metabolites in response to dietary Gln supplementation in piglets. Sixteen, 21-d-old pigs were weaned and assigned randomly to 2 isonitrogenous diets: 1) Gln diet, which contained 1% L-Gln (as-fed basis), and 2) control diet, which contained L-Ala to make this diet isonitrogenous with the Gln diet. Serum samples were collected to characterize metabolites after a 30-d treatment. in addition, 4 liver samples per treatment were collected to examine enzyme activity and gene expression involved in metabolic regulation. Results indicated that 12 metabolites were altered (P < 0.05) by Gln treatment, including carbohydrates, AA, and fatty acids. A leave-one-out cross validation of random forest analysis indicated that Pro was most important among the 12 metabolites. Thus, these data demonstrate that the control and Gln-supplemented pigs differed (P < 0.05) in terms of metabolism of carbohydrates, Pro, Tyr, and glycerophospholipids. Principal component analysis yielded separate clusters of profiles between the Gln and control groups. Metabolic enzyme activities of Ala aminotransferase and hexokinase increased by 26.8% (P = 0.026) and 26.2% (P = 0.004) in the liver of Gln-supplemented pigs vs. control, respectively, whereas pyruvate kinase (PK) activity decreased by 29.1% (P = 0.001). The gene expression of PK in the liver decreased by 66.1% (P = 0.034) by Gln treatment for 30 d. No differences were observed for the mRNA abundance of mammalian target of rapamycin and PPARγ. On the basis of these data, Gln treatment affected carbohydrate, lipid, and AA metabolism in the whole body of the early weaned piglets. These findings provide insight into specific metabolic pathways and lay the groundwork for the complex metabolic alteration in response to dietary Gln supplementation of pigs.

Epitaxial graphene on SiC(0001): functional electrical microscopy studies and effect of atmosphere

Surface potential distribution, V(CPD), and evolution of atmospheric adsorbates on few and multiple layers (FLG and MLG) of graphene grown on SiC(0001) substrate have been investigated by electrostatic and Kelvin force microscopy techniques at T = 20-120 °C. The change of the surface potential distribution, ΔV(CPD), between FLG and MLG is shown to be temperature dependent. The enhanced ΔV(CPD) value at 120 °C is associated with desorption of adsorbates at high temperatures and the corresponding change of the carrier balance. The nature of the adsorbates and their evolution with temperature are considered to be related to the process of adsorption and desorption of the atmospheric water on MLG domains. We demonstrate that both the nano- and microscale wettability of the material are strongly dependent on the number of graphene layers.

Local hemodynamic disturbance accelerates early thrombosis of small-caliber expanded polytetrafluoroethylene grafts

OBJECTIVE

Small-caliber expanded polytetrafluoroethylene (ePTFE) grafts cannot be used widely in the clinical situation because of early thrombosis and occlusion. This unsolved and under-recognized problem warrants further investigation.

METHODS

Grafts of uncoated ePTFE (n = 6) and anti-CD34-coated ePTFE (n = 6) were implanted unilaterally into the carotid artery in 12 domestic pigs. Ultrasonography was used to test the proximal and distal anastomotic stoma morphology, diameters and blood velocities. A thrombosis instrument was used to examine the blood coagulation state. After seven days, the pigs were sacrificed and the implanted grafts were excised for general and histological analysis. Computational fluid dynamics was used to investigate the blood flow fields of the implanted grafts and to calculate parameters that might be indicative of thrombosis.

RESULTS

Thrombosis was detected in 10 of 12 (83.3%) implanted ePTFE grafts, 5 in uncoated grafts and 5 in anti-CD34-coated grafts. Endothelial cell coverage was observed in both uncoated and anti-CD34-coated grafts. No obvious abnormalities in anastomotic stoma or blood coagulation state were observed. Computer-based local hemodynamic simulation showed the low flexibility of synthetic ePTFE grafts caused obvious coarctation. Local wall pressure, velocity and wall shear stress were much higher than in the contralateral normal vessel.

CONCLUSIONS

The patency of small-caliber ePTFE grafts for clinical use is impaired by early thrombosis due to mixed causes. Local hemodynamic disturbance was the most powerful predictor of early thrombosis. Decreasing local hemodynamic disturbance, improving the quality of anastomotic stoma, selecting reasonable anticoagulation strategies and promoting rapid endothelialization may increase the long-term patency of small-caliber vascular grafts.

Use of bronchoalveolar lavage enzyme-linked immunospot for diagnosis of smear-negative pulmonary tuberculosis

OBJECTIVE

To compare the diagnostic validity of blood enzyme-linked immunospot assay (ELISpot), broncho-alveolar lavage (BAL) ELISpot and the tuberculin skin test (TST) in patients with pulmonary smear-negative tuberculosis (TB) in a country with high TB prevalence.

DESIGN

In a prospective, hospital-based study, 107 patients with suspected TB were tested simultaneously using blood and BAL ELISpot and TST.

RESULTS

Of 102 patients with active pulmonary TB, 36 (35.3%) were diagnosed with TB, while 66/102 (64.7%) had a non-TB diagnosis. The sensitivity and specificity for ELISpot on mononuclear cells from BAL fluid was respectively 94.4% (95%CI 81.9-98.5) and 78.1% (95%CI 66.6-86.5). The specificity of BAL ELISpot was significantly higher than that of blood ELISpot (P = 0.011). Compared with blood ELISpot and TST, BAL ELISpot was not significantly influenced by previous history of TB (OR 2.05, P > 0.05) or household contact with a patient with active TB (OR 2.41, P > 0.05).

CONCLUSION

ELISpot on BAL appears to be a more rapid and sensitive supplementary test than on blood for the diagnosis of active TB patients with a negative sputum smear in a developing country setting with high TB prevalence and access to bronchoscopy and ELISpot assay. However, the test's utility was limited by its moderate specificity.

Functional analysis of DNA methylation in lung cancer

OBJECTIVES

We aimed to explore the DNA methylation difference between lung cancer samples and non-cancer lung samples, and to investigate the role of DNA methylation in the mechanism of lung cancer development. Besides, we analyzed the transcriptional regulation network of DNA methylation and the miRNAs regulated by DNA methylation. This study provides a framework for DNA methylation in other tumors or diseases.

MATERIALS AND METHODS

DNA methylation and gene expression profiles used were obtained from Gene Expression Omnibus. Firstly, we identified differentially methylated genes (DMGs) by Student's t-test. Then we detected the biological processes and pathways changed in lung cancer by Gene Ontology (GO) and KEGG pathway enrichment analysis. The transcriptional factors in differential genes were identified and the microRNAs regulated by them were also obtained in TransmiR.

RESULTS

We obtained 108 DMGs between lung cancer samples and non-cancer samples. Besides development related biological processes and pathways were dramatically disordered. For the DMGs, we identified 11 transcriptional factors regulating them. Moreover, we screened out 21 relationships between DMGs and their transcriptional targets. Five microRNAs are reported to be regulated by DNA methylation genes. Finally a regulation network of DNA methylation was constructed.

CONCLUSIONS

DNA methylation participates in carcinogenesis at the transcriptional and post-transcriptional level. Aberrant DNA methylation will prevent its binding with the upstream regulatory proteins, inhibit the function of downstream target genes and regulate the expression of downstream miRNA, and consequently affect cell development, immunoresponse and apoptosis.

Isoflurane and sevoflurane increase interleukin-6 levels through the nuclear factor-kappa B pathway in neuroglioma cells

BACKGROUND

Isoflurane can increase pro-inflammatory cytokine interleukin (IL)-6 levels. However, the up-stream mechanism remains unknown. Nuclear factor-kappa B (NF-κB) promotes the generation of pro-inflammatory cytokines. We examined the effects of isoflurane and sevoflurane on the NF-κB signalling pathway and its association with IL-6 levels in cultured cells.

METHODS

H4 human neuroglioma cells (H4 cells), and mouse primary neurones and microglia were treated with 2% isoflurane or 4.1% sevoflurane for 6 h, for analysis of IL-6 and NF-κB. Pyrrolidine dithiocarbamate (an NF-κB inhibitor) or 2-deoxy-d-glucose (2-DG) (an inhibitor of glucose glycolysis) was applied 1 h before anaesthetic treatment.

RESULTS

Isoflurane or sevoflurane treatment increased the levels of IL-6 [isoflurane: 410% (54); sevoflurane: 290% (24)], the nuclear levels of NF-κB [isoflurane: 170% (36); sevoflurane: 320% (30)], and the transcription activity of NF-κB in H4 cells. Moreover, isoflurane enhanced the transcription activity of NF-κB in mouse microglia, but not primary neurones. Finally, pyrrolidine dithiocarbamate and 2-DG attenuated isoflurane-induced increases in IL-6 and NF-κB, and the transcription activity of NF-κB.

CONCLUSIONS

These studies in H4 cells suggest that the NF-κB signalling pathway could contribute to isoflurane or sevoflurane-induced neuroinflammation. This could lead to the targeted intervention of anaesthetic-induced neuroinflammation.

Abstract 2622: TMEFF2 inhibits human prostate cancer cell migration through its G protein activating domain

The type I transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) is expressed mainly in brain and prostate. Expression of TMEFF2 is deregulated in a significant fraction of primary and metastatic prostate, suggesting a role in this disease. In fact, we have previously shown that TMEFF2 can function as a tumor suppressor in vitro, inhibiting monolayer and anchorage-independent cellular growth in HEK293T cells and sarcosine-induced cell migration and invasion in benign prostate epithelial RWPE-1 cells. However, the molecular mechanisms involved in the tumor suppressor phenotype of TMEFF2 are not clear. TMEFF2 has several biologically important features. The extracellular domain contains two follistatin domains and an epidermal growth factor-like (EGF) domain, while the transmembrane domain and short cytoplasmic tail have features resembling a G protein activating domain, suggesting that it may signal through a G protein. We hypothesize that the tumor suppressor activity of TMEFF2 is, at least in part, due to signaling mediated by the putative G protein activating domain. In order to test this hypothesis, here we investigate the role of TMEFF2 and a mutant lacking the cytoplasmic tail on cellular migration of prostate cancer cells, and begin analyzing the molecular mechanisms involved in this effect.

Our results demonstrate that overexpression of TMEFF2 in human prostate cancer cell line RWPE-2 causes about 60% decrease in cellular migration as assessed by wound-healing assays. Interestingly, we found that RWPE-2 cells overexpressing TMEFF2 have a defect in cell spreading on culture dishes (∼20% decrease) as well as on vitronectin-coated coverslips (∼30% decrease) and that this defect is accompanied by abolished focal adhesion and stress fiber formation. Moreover, the inhibition of TMEFF2 on cellular migration is dependent on its G protein activating domain as deletion of this domain rescues migration, spreading on vitronectin, and focal adhesion formation. The specific G protein pathway(s) involved in the anti-migratory effect of TMEFF2 is currently under investigation.

In summary, the data presented here indicate, for the first time, that the anti-migratory effect of TMEFF2 in human prostate cancer cells is mediated by its G protein activating domain. These results raise the possibility that TMEFF2 agonists may be used as therapeutic agents to mediate tumor suppression via this pathway.

Citation Format: Xiaofei Chen, C. Justus, L Yang, M.j. Ruiz-Echevarria. TMEFF2 inhibits human prostate cancer cell migration through its G protein activating domain. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2622. doi:10.1158/1538-7445.AM2013-2622

The association of vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D levels with generalized vitiligo

BACKGROUND

Vitiligo is an acquired depigmentation autoimmune disorder that has been described as being associated with lower levels of 25-hydroxyvitamin D [25(OH)D]. Genetic variations within the vitamin D receptor (VDR) gene could lead to significant receptor dysfunction, and could further affect the formation of the biologically active 25(OH)D. Therefore, we hypothesized that VDR polymorphisms might be involved in vitiligo by affecting the formation of 25(OH)D.

OBJECTIVES

To evaluate the potential association between VDR polymorphisms and vitiligo susceptibility and the serum levels of 25(OH)D.

METHODS

We performed a hospital-based study of 749 patients with vitiligo and 763 matched controls. We investigated four VDR polymorphisms (FokI, BsmI, ApaI and TaqI) to determine whether they are associated with vitiligo susceptibility in the Chinese population. In addition, the levels of 25(OH)D were measured to evaluate possible associations between the VDR polymorphic variants and clinical and laboratory findings of vitiligo.

RESULTS

A significantly decreased risk of developing vitiligo was found to be associated with the BsmI-B, ApaI-A and TaqI-t alleles. According to the genotype distribution, 25(OH)D concentrations were significantly higher in patients carrying the FokI ff or ApaI AA genotypes compared with those carrying the FF or aa genotypes. Logistic regression analysis also showed a dose-response relationship between decreased risk of vitiligo and increased 25(OH)D levels in ApaI-A variant genotype carriers.

CONCLUSIONS

Our findings suggest that these VDR polymorphisms are associated with 25(OH)D levels and that there exists a genetic predisposition for vitiligo in the Chinese population.

Phosphatidylinositol 3 kinase/protein kinase B is responsible for the protection of paeoniflorin upon H₂O₂-induced neural progenitor cell injury

Promoting neural stem/progenitor cell (NSC/NPC) survival in the pro-apoptotic environment is critical to stem cell replacement for neurodegenerative disease therapy. Paeoniflorin (PF), one of the principal bioactive components in Paeoniae Radix, has been used widely in central nervous system (CNS) diseases treatment and serves as an antioxidant to protect neurons against oxidative stress. The present study investigated the protective effects of PF on NPC injury induced by hydrogen peroxide (H₂O₂). After challenge with 200 μM H₂O₂ for 2h, loss of cell viability and excessive apoptotic cell death were observed in cultured NPC, PF treatment conferred protective effects against the loss of cellular viability in a concentration-dependent manner. PF pretreatment also inhibited NPC apoptosis induced by H₂O₂ by reversing the decreased level of Procaspase-3 and balancing Bcl-2 and Bax expression. Furthermore, PF-mediated NPC protection was associated with an increase in phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt-1) phosphorylation in a time- and concentration-dependent manner. Selective inhibition of PI3K using LY294002 abolished PF-mediated phosphorylation of Akt-1 and NPC protection upon oxidative stress. These data suggest that PF-mediated NPC protection on H₂O₂ injury is reliant on the activation of the PI3K/Akt-1 pathway, giving insight to an essential role of PF in NPC protection.

A novel HLA-A allele, A*31:65, was identified by sequence-based typing in a Chinese potential donor

A*31:65: one nucleotide change resulting in a new motif CAC at codon 84 in HLA-A.