Effect of Nanoparticles on the Survival and Development of Vitrified Porcine GV Oocytes

BACKGROUND: Some mammalian oocytes have been successfully cryopreserved by vitrification. However, the survival and developmental rate of vitrified oocytes is still low. The incorporation of nanoparticles into cryoprotectant (CPA) may improve the efficiency of vitrification by changing the properties of solutions.

MATERIALS AND METHODS

The toxicity of different concentrations of hydroxy apatite (HA), silica dioxide (SO₂), aluminum oxide (Al₂O₃) and titanium dioxide (TiO₂) nanoparticles (20 nm in diameter) to oocytes was tested and the toxicity threshold value of each nanoparticle was determined. Porcine GV oocytes were vitrified in optimized nano-CPA, and effects of diameter and concentration of nanoparticles on the survival rate and developmental rate of porcine GV oocytes were compared.

RESULTS

HA nanoparticles have demonstrated the least toxicity among four nanoparticles and the developmental rate of GV-stage porcine oocytes was 100% when its concentration was lower than 0.5%. By adding 0.1% HA into VS, the developmental rate of GV-stage porcine oocytes (22%) was significantly higher than other groups. The effect of vitrification in nano-CPA on oocytes was related to the concentration of HA nanoparticles rather than their size. By adding 0.05% HA nanoparticles (60nm in diameter), the developmental rate increased dramatically from 14.7% to 30.4%.

CONCLUSION

Nano-cryopreservation offers a new way to improve the effect of survival and development of oocytes, but the limitation of this technology shall not be ignored.

Loss of ATF3 promotes hormone-induced prostate carcinogenesis and the emergence of CK5(+)CK8(+) epithelial cells

Steroid sex hormones can induce prostate carcinogenesis, and are thought to contribute to the development of prostate cancer during aging. However, the mechanism for hormone-induced prostate carcinogenesis remains elusive. Here we report that activating transcription factor 3 (ATF3) – a broad stress sensor – suppressed hormone-induced prostate carcinogenesis in mice. While implantation of testosterone and estradiol (T+E₂) pellets for 2 months in wild-type mice rarely induced prostatic intraepithelial neoplasia (PIN) in dorsal prostates (1 out of 8 mice), loss of ATF3 led to the appearance of not only PIN but also invasive lesions in almost all examined animals. The enhanced carcinogenic effects of hormones on ATF3-deficient prostates did not appear to be caused by a change in estrogen signaling, but were more likely a consequence of elevated androgen signaling that stimulated differentiation of prostatic basal cells into transformation-preferable luminal cells. Indeed, we found that hormone-induced lesions in ATF3-knockout mice often contained cells with both basal and luminal characteristics, such as p63⁺ cells (a basal cell marker) showing luminal-like morphology, or cells double-stained with basal (CK5⁺) and luminal (CK8⁺) markers. Consistent with these findings, low ATF3 expression was found to be a poor prognostic marker for prostate cancer in a cohort of 245 patients. Our results thus support that ATF3 is a tumor suppressor in prostate cancer.

G-quadruplex enhanced fluorescence of DNA-silver nanoclusters and their application in bioimaging

Guanine proximity based fluorescence enhanced DNA-templated silver nanoclusters (AgNCs) have been reported and applied for bioanalysis. Herein, we studied the G-quadruplex enhanced fluorescence of DNA-AgNCs and gained several significant conclusions, which will be helpful for the design of future probes. Our results demonstrate that a G-quadruplex can also effectively stimulate the fluorescence potential of AgNCs. The major contribution of the G-quadruplex is to provide guanine bases, and its special structure has no measurable impact. The DNA-templated AgNCs were further analysed by native polyacrylamide gel electrophoresis and the guanine proximity enhancement mechanism could be visually verified by this method. Moreover, the fluorescence emission of C3A (CCCA)4 stabilized AgNCs was found to be easily and effectively enhanced by G-quadruplexes, such as T30695, AS1411 and TBA, especially AS1411. Benefiting from the high brightness of AS1411 enhanced DNA-AgNCs and the specific binding affinity of AS1411 for nucleolin, the AS1411 enhanced AgNCs can stain cancer cells for bioimaging.

Infected hematopoietic stem cells and with integrated HBV DNA generate defective T cells in chronic HBV infection patients

A weak T-cell response plays a key role in the persistence of hepatitis B virus (HBV) infection. We aimed to confirm that T-cell defects in patients with chronic HBV infection are associated with HBV DNA infection of bone marrow (BM) hematopoietic stem cells (HSCs). Using reverse transcription polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH), we observed the transcription of HBsAg coding genes and confirmed the integration of HBV DNA in CD34(+) BM HSCs from chronic HBV infection patients. T cells were generated by coculturing the HSCs with delta-like ligand 1-expressing OP9 (OP9-DL1) cells. The phenotypes of the T cells were then evaluated by flow cytometric (FACS) analysis on days 14 and 25. The results demonstrated that fewer CD3(+) TCRaβ(+) CD3(+) CD4(+) and CD4(+) CD8(+) T cells were generated from the HSCs of the patients than from the healthy controls, (P < 0.01) but the frequency of CD3(+) D8(+) T cells was not significantly different between the two group (P > 0.05). In contrast, CD4(+) CD25(+) T cells were more in the patient group than in healthy controls (P < 0.01) on both days 14 and 25. There were fewer CD3(+) CD4(+) /CD3(+) CD8(+) cells in the patient group than in the healthy control group on day 25 (P < 0.05). Less proliferation and lower levels of IL-2 and IFN- γ were also observed in the patient group compared with the control group (P < 0.05).These data suggest that HBV DNA infected and integrated into the BM HSCs from patients with chronic HBV infection and that these BM HSCs generated defective T cells.

Attentional tradeoffs in the pigeon

We deployed the Multiple Necessary Cues (MNC) discrimination task to see if pigeons can simultaneously attend to four different dimensions of complex visual stimuli. Specifically, we trained nine pigeons (Columba livia) on a go/no go discrimination to peck only 1 of 16 compound stimuli created from all possible combinations of two stimulus values from four separable visual dimensions: shape (circle/square), size (large/small), line orientation (horizontal/vertical), and brightness (dark/light). Some of the pigeons had CLHD (circle, large, horizontal, dark) as the positive stimulus (S+), whereas others had SSVL (square, small, vertical, light) as the S+. We recorded touchscreen pecking during the first 15 s that each stimulus was presented on each training trial. Discrimination training continued until pigeons' rates of responding to all 15 negative stimuli (S-s) fell to less than 15% of their response rates to the S+. All pigeons acquired the MNC discrimination, suggesting that they attended to all four dimensions of the multidimensional stimuli. Learning rate was similar for all four dimensions, indicating equivalent salience of the discriminative stimuli. The more dimensions along which the S-s differed from the S+, the faster was discrimination learning, suggesting an added benefit from increasing perceptual disparities of the S-s from the S+. Finally, evidence of attentional tradeoffs among the four dimensions was seen during discrimination learning, raising interesting questions concerning the possible control of behavior by elemental and configural stimuli.

Inhibition of eIF2α dephosphorylation enhances TRAIL-induced apoptosis in hepatoma cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an inducer of cancer cell death that holds promise in cancer therapy. Cancer cells are more susceptible than normal cells to the cell-death-inducing effects of TRAIL. However, a variety of cancer cells are resistant to TRAIL through complex mechanisms. Here, we investigate the effects of inhibition of eukaryotic initiation factor 2 subunit α (eIF2α) dephosphorylation on TRAIL-induced apoptosis in hepatoma cells. Treatment of hepatoma cells with salubrinal, an inhibitor of eIF2α dephosphorylation, enhances TRAIL-induced eIF2α phosphorylation, CCAAT/enhancer-binding protein homologous protein (CHOP) expression and caspase activation. Salubrinal enhances TRAIL-induced apoptosis, which could be abrogated by caspase inhibitor. Overexpression of phosphomimetic eIF2α (S51D) enhances TRAIL-induced CHOP expression, caspase 7 and PARP cleavage and apoptosis. By contrast, overexpression of phosphodeficient eIF2α (S51A) abrogates the stimulation of TRAIL-induced apoptosis by salubrinal. Moreover, knockdown of growth arrest and DNA damage-inducible protein 34 (GADD34), which recruits protein phosphatase 1 to dephosphorylate eIF2α, enhances TRAIL-induced eIF2α phosphorylation, CHOP expression, caspase activation and apoptosis. Furthermore, the sensitization of hepatoma cells to TRAIL by salubrinal is dependent on CHOP. Knockdown of CHOP abrogates the stimulation of TRAIL-induced caspase activation and apoptosis by salubrinal. Combination of salubrinal and TRAIL leads to increased expression of Bim, a CHOP-regulated proapoptotic protein. Bim knockdown blunts the stimulatory effect of salubrinal on TRAIL-induced apoptosis. Collectively, these findings suggest that inhibition of eIF2α dephosphorylation may lead to synthetic lethality in TRAIL-treated hepatoma cells.

Tobacco smoking associated with the increases of the bronchoalveolar levels of interleukin-5 and interleukin-1 receptor antagonist in acute eosinophilic pneumonia

BACKGROUND

There is a strong association between tobacco smoking and acute eosinophilic pneumonia (AEP) and tobacco smoking has been related to onset of AEP, but the mechanisms for causing AEP are largely unknown. AEP is characterized by locally high levels of interleukin-5 (IL-5) and interleukin-1 receptor antagonist (IL-1RA). Thus, tobacco smoking may relate to the high levels of IL-5 and IL-1RA in AEP.

AIM

We aimed to determine whether the rate of tobacco smoking positively related to the high levels of IL-5 and IL-1RA.

PATIENTS AND METHODS

In the study, 155 AEP patients and 135 control healthy subjects were recruited by the Clinical Research Center at General Hospital of Shenyang Military Area Command (Shenyang, China). All the subjects were interviewed regarding for the tobacco smoking rate. The number of eosinophils was counted in all subjects. The relative expressive levels of IL-5 and IL-1RA were measured with ELISA in Bronchoalveolar lavage (BAL) and serum.

RESULTS

The BAL levels of IL-5, IL-1ra, eosinophils and lymphocytes positively correlates with the rate of tobacco smoking in AEP patients (p < 0.005) comparing with those in healthy control groups. No significant association was observed between the serum levels IL-5 and IL-1ra and the rate of tobacco smoking in AEP patients (p > 0.05) comparing with those in healthy control groups.

CONCLUSIONS

Smoking increases the BAL levels of IL-5 and IL-1RA, which is associated with the onset of AEP.

The relationship between DNA sequences and oligonucleotide-templated silver nanoclusters and their fluorescence properties

A novel approach was developed to study the relationship between DNA sequences and DNA-templated silver nanoclusters (DNA-Ag NCs) in detail by using an ordinary DNA strand as an example. Three kinds of Ag NCs are formed by using the DNA strand as a scaffold. By dividing the DNA template into several parts according to their different affinities to Ag(+) , it was found that the fluorescence properties of DNA-Ag NCs are related to not only the sequences but also to the position of different parts in the template, which provides a more efficient approach to obtain DNA-Ag NCs with required photoluminescence properties and may ultimately contribute to the targeted synthesis of DNA-Ag NCs.

Synergistic function of Kras mutation and HBx in initiation and progression of hepatocellular carcinoma in mice

Although the activation of Ras pathway is frequently observed in human hepatocellular carcinoma (HCC), the in vivo role of Ras activation in HCC initiation and progression is underdetermined. To test the consequence of Kras activation in hepatocyte, we generated a hepatocyte-specific Kras(G12D) transgenic mouse strain and observed spontaneous development of HCC in these mice. Remarkably, HBV X protein (HBx) expression significantly promotes the formation and malignant progression of Kras(G12D)-driven HCC as shown with the accelerated tumor onset, the increased tumor burden and the more poorly differentiated lesions. At the cellular level, concomitant expression of Kras(G12D) and HBx results in a robust increase in hepatocellular proliferation. We reveal that the Akt, MAPK, p53 and TGF-β pathways are deregulated in the Kras(G12D)-driven HCCs. Also, the dysregulation is more pronounced in the HCCs developed in Kras(G12D) and HBx double transgenic mice. In addition, the altered expressions of β-catenin, CD44 and E-cadherin are only observed in the Kras(G12D) and HBx double transgenic mice. These results demonstrate a crucial role of Ras activation in hepatocellular carcinogenesis and the functional synergy between Kras(G12D) and HBx in HCC initiation and progression. The novel genetic mouse models that closely recapitulate the histopathologic progression and molecular alterations of human HCC may potentially facilitate the future therapeutic studies.

Rescue from dominant follicle atresia by follicle-stimulating hormone in mice

We investigated the effects of follicle-stimulating hormone (FSH) on atresia of the dominant follicle and changes in relevant apoptosis genes in granulosa cells of dominant follicles regulated by FSH in vivo. Four-week-old mice were administered FSH by intraperitoneal injection to induce follicular maturation. Granulosa cells of dominant follicles were collected at 48, 72, and 96 h after the first FSH injection. Phosphate-buffered saline was injected as a control. The mRNA levels of relevant granulosa cell apoptosis genes were examined by real-time quantitative polymerase chain reaction, and apoptosis of granulosa cells in dominant ovarian follicles was determined by the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Apoptosis in granulosa cells of dominant follicles was almost TUNEL-negative at 48, 72-66, 72, and 96-90 h after the first FSH injection, but granulosa cell apoptosis in dominant follicles was clearly detected at 96, 102, and 102-96 h by TUNEL. The BIM, caspase-3, and caspase-9 mRNA expression levels were significantly lower after FSH treatment at 72-66 and 96-90 h, compared with that at 72 and 96 h (P < 0.05). Caspase-8 and FasL mRNA expressions did not respond to FSH. FSH rescued granulosa cells from apoptosis when the relevant apoptosis genes were upregulated in early atretic follicles. FSH did not rescue granulosa cells from apoptosis if the DNA was cut into fragments by endonucleases. Thus, the rescue by FSH of granulosa cells from apoptosis and dominant follicle atresia may be accomplished by inhibition of apoptosis in mitochondria.

WASF3 regulates miR-200 inactivation by ZEB1 through suppression of KISS1 leading to increased invasiveness in breast cancer cells

The WASF3 gene promotes invasion and metastasis in breast cancer cells which have undergone epithelial-to-mesenchyme transition (EMT). Overexpression of WASF3 in cells that do not show EMT increases their invasion potential as a result of increased ZEB1/2 levels which specifically suppress the anti-invasion chromosome 1 miR-200a/ 200b/429 cluster. ZEB1/2 upregulation by WASF3 results from downregulation of KISS1, leading to release of inhibition of NFκB by IκBα. We further show that ZEB1 expression is regulated by the NFκB transcription factor. Knockdown of WASF3 in breast cancer cells leads to reduced ZEB1 levels and increased miR-200 and E-cadherin levels, resulting in loss of invasion potential. The central regulation of this interactive pathway by WASF3 accounts for the increased invasion associated with increased WASF3 expression seen in aggressive breast cancer cells. WASF3, therefore, is a potential target to suppress invasion and metastasis in breast cancer cells.

Characterization of the carbonic anhydrases 15b expressed in PGCs during early zebrafish development

The main function of carbonic anhydrases is to regulate acid-base balance. In the present study, the zebrafish CA15b sequence was identified from the National Center for Biotechnology Information database (accession No. NM_213182). The 1716 base pair full-length cDNA of CA15b was obtained by 3' and 5'-rapid amplification of cDNA ends analysis. It was expressed (reverse transcription polymerase chain reaction and Western blot analysis) in the ovary, heart, brain, and muscle, but not in testis or liver. Based on in situ hybridization, CA15b mRNA was transcribed in the ooplasm of stage I to stage II oocytes, in the cortex of stage III oocytes, and along the periphery of stage IV oocytes. Furthermore, this protein was localized (immunohistochemistry) in the plasma membrane of oocytes. Based on whole-mount in situ hybridization, CA15b mRNA was present in every blastomere of embryos from one-cell to blastula stages. Strong signals of the transcripts were present along cleavage furrows of two- and eight-cell stage embryos, which subsequently condensed into four clusters of cells during the blastula stage. During subsequent stages, the four groups of CA15b-expressing cells appeared to move toward the dorsal side of the embryos, clustered into two groups on either side of the midline, and remained visible as they migrated toward the region of the gonad in embryos at 24 hours postfertilization. Expression patterns of CA15b were similar to those of vasa, a marker of primordial germ cells. Thus, we hypothesized that CA15b might be necessary for development of primordial germ cells and female germ cells in zebrafish.