A 78 kDa host cell invasion protein of Neospora caninum as a potential vaccine candidate.

Neosporosis is an intracellular protozoan disease caused by Neospora caninum. Until now, there is no effective vaccine to prevent neosporosis. The host cell binding protein has the potential as neosporosis vaccine. In the present study, a T7 phage display library was constructed and screened using Vero cells to obtain host cell binding protein of N. caninum. Two host cell binding proteins, a hypothetical protein of 78 kDa (named as NcP78) homologous to the acylglycerol lipase of Toxoplasma gondii ME49 (XP_002370319.1) and NcGRA7 (known as a dense granules protein that is involved in the invasion of N. caninum to the host cells), were identified. Immune responses induced by recombinant NcP78 and NcGRA7 proteins and their protective efficacies against homologous challenge in BALB/c mice were evaluated respectively. Results showed that recombinant NcP78 and NcGRA7 could elicit both Th1 and Th2 immune responses (with the elevated levels of IgG1 and IgG2a antibody), but predominately a Th2 immune response with a high level of IgG1. The ani-NcP78 and anti-NcGRA7 serum also had inhibitory effects on N. caninum invasion to Vero cells in vitro, which indicated that both NcP78 and NcGRA7 proteins were involved in host cell invasion. Recombinant NcP78 and NcGRA7 could not prolong the survival times and improve the survival rates of dams, but could prolong the survival times and improve the survival rates of offspring significantly. Moreover, the recombinant NcP78 and NcGRA7 could reduce the brain parasite load of dams and offspring. Though these protein vaccines could not effectively alleviate the symptom of abortion, they could increase the number of born offspring significantly, indicating that Nc78 and NcGRA7 recombinant proteins could provide a partial protection against N. caninum infection in mice.

MicroRNAs in the immune organs of chickens and ducks indicate divergence of immunity against H5N1 avian influenza.

Chickens are susceptible to the highly pathogenic H5N1 strain of avian influenza virus (HPAIV), whereas ducks are not. Here, we used high-throughput sequencing to analyse the microRNA expression in the spleen, thymus and bursa of Fabricius of H5N1-HPAIV-infected and non-infected chickens and ducks. We annotated the genomic positions of duck microRNAs and we compared the microRNA repertoires of chickens and ducks. Our results showed that the microRNA expression patterns in the homologous immune organs of specific-pathogen-free (SPF) chickens and ducks diverge substantially. Moreover, there was larger divergence between the microRNA expression patterns in immune organs of HPAIV-infected chickens than HPAIV-infected ducks. Together, our results might help to elucidate the roles of microRNAs in the divergent immunity of chickens and ducks against H5N1 HPAIV.

The effect of leader peptide mutations on the biological function of bovine myostatin gene.

The growth of muscle fibers can be negatively regulated by bovine myostatin. The first two exons of myostatin gene code for the N-propeptide and its third exon codes for the C-polypeptide. Myostatin is secreted as a latent configuration formed by dimerization of two matured C peptides non-covalently linked with the N terminal pro-peptide. Pro-peptide has two distinct functions in guiding protein folding and regulating biological activity of myostatin. When the structure of the leader peptide is altered via mutations resulting in more tight binding with the mature peptide, myostatin function is inhibited, resulting in the changes of P21 and CDK2 expression levels which are related to the regulation of cell cycle. In the present study, the coding region of bMSTN (bovine myostatin) gene was amplified and mutated (A224C and G938A) through fusion PCR, and the mutated bMSTN gene (bMSTN-mut) was inserted in frame into the pEF1a-IRES-DsRed-Express2 vector and transfected into bovine fibroblast cells. The expression levels of bMSTN-mut, P21 and CDK2 (cyclin dependent kinase 2) were examined with qPCR and Western-blotting. Changes in cell cycle after transfection were also analyzed with flow cytometry. The results indicated that leader peptide mutation resulted in down-regulation of P21 expression levels and up-regulation of CDK2 expression levels. The flow cytometry results showed that the proportion of cells in the G0/G1-phase was lower and that of cells in the S-phase was higher in bMSTN-mut transfected group than that in the control group. The proliferation rate of bMSTN-mut transfected cells was also significantly higher than that of the control cells. In conclusion, the studies have shown that the pEF1a-IRES-DsRed-Express2-bMSTN-mut recombinant plasmid could effectively promote the proliferation of bovine fibroblast cells. The site-directed mutagenesis of bMSTN gene leader peptide and in vitro expression in bovine fibroblast cells could be helpful to further the studies of bMSTN in regulating bovine muscle cell growth and development.

Overexpression of Aldo-keto reductase family 1 B10 protein in ductal carcinoma in situ of the breast correlates with HER2 positivity.

BACKGROUND: Ductal carcinoma in situ of the breast constitutes the early stage of breast cancer when cancer cells are confined by the intact myoepithelial cell layer. Transition from DCIS to invasive carcinoma is a process yet poorly understood. MATERIALS AND METHODS: By liquid chromatography (LC) and mass spectrometry (MS/MS) methods, we analyzed this early event using paired samples of micro-dissected cells overlaid with focally disrupted myoepithelial layers and their adjacent counterparts within the intact duct from formalin-fixed paraffin-embedded blocks. RESULTS: AKR1B10, a member of Aldo-keto reductase family, was shown to be abundantly located in the filtering cells among a catalog of proteins. Moreover, strong correlation between AKR1B10 and HER2 positivity was found in an independent cohort of DCIS samples. CONCLUSION: AKR1B10 could become a potential diagnosis and therapeutic marker for early breast cancers with HER2 overexpression and poor prognosis.

Altered expression levels of IDH2 are involved in the development of colon cancer.

IDH2 encodes a mitochondrial metabolic enzyme that converts isocitrate to α-ketoglutarate (α-KG) by reducing nicotinamide adenine dinucleotide phosphate (NADP(+)) to NADPH and participates in the citric acid cycle for energy production. Notably, this gene has been shown to be critical for cell proliferation. The abnormal expression of IDH2 has been reported in several types of cancer, and mutations in IDH2 have been identified in gliomas and acute myelogenous leukemia. The overexpression of IDH2 has been reported in endometrial, prostate and testicular cancer as well as in Kashin-Beck disease. In this study, we observed that IDH2 expression was significantly downregulated in early phase but was upregulated in advanced phase colon carcinoma compared to peritumoral tissues. In addition, we demonstrated that the growth of a colon carcinoma cell line was inhibited by IDH2-siRNA and increased following transfection with an IDH2-overexpressing plasmid. These results indicate that IDH2 may play a unique role in the development of colon carcinoma.

Neospora caninum: in vitro culture of tachyzoites in MCF-7 human breast carcinoma cells.

The development of Neospora caninum tachyzoites, an apicomplexan protozoan parasite, was studied in vitro using the human breast carcinoma cell 7 (MCF-7) as the host cell line. The extracellular NC-1 tachyzoites in MCF-7 cells were observed and counted daily for 6 consecutive days post-infection to establish the growth curve. The intracellular parasites were observed by acridine orange staining using Laser scanning confocal microscope. The results indicated that NC-1 tachyzoites invaded MCF-7 cells and multiplied intracellularly. The number of extracellular NC-1 tachyzoites started to increase rapidly around day 3 and reached the maximum number around day 4. Results from the present study suggested that MCF-7 cells were susceptible to NC-1 tachyzoites and could be used as an alternative cell line for in vitro studies.