Nestin+/CD31+ cells in the hypoxic perivascular niche regulate glioblastoma chemoresistance by upregulating JAG1 and DLL4.

BACKGROUND: Failure of glioblastoma (GBM) therapy is often ascribed to different types of glioblastoma stem-like cell (GSLC) niche; in particular, a hypoxic perivascular niche (HPVN) is involved in GBM progression. However, the cells responsible for HPVNs remain unclear. METHODS: Immunostaining was performed to determine the cells involved in HPVNs. A hypoxic chamber and 3-dimensional (3D) microfluidic chips were designed to simulate a HPVN based on the pathological features of GBM. The phenotype of GSLCs was evaluated by fluorescence scanning in real time and proliferation and apoptotic assays. The expression of JAG1, DLL4, and Hes1 was determined by immunostaining, ELISA, Western blotting, and quantitative PCR. Their clinical prognostic significance in GBM HPVNs and total tumor tissues were verified by clinical data and The Cancer Genome Atlas databases. RESULTS: Nestin+/CD31+ cells and pericytes constitute the major part of microvessels in the HPVN, and the high ratio of nestin+/CD31+ cells rather than pericytes are responsible for the poor prognosis of GBM. A more real HPVN was simulated by a hypoxic coculture system in vitro, which consisted of 3D microfluidic chips and a hypoxic chamber. Nestin+/CD31+ cells in the HPVN were derived from GSLC transdifferentiation and promoted GSLC chemoresistance by providing more JAG1 and DLL4 to induce downstream Hes1 overexpression. Poor GBM prognosis correlated with Hes1 expression of tumor cells in the GBM HPVN, and not with total Hes1 expression in GBM tissues. CONCLUSIONS: These results highlight the critical role of nestin+/CD31+ cells in HPVNs that acts in GBM chemoresistance and reveal the distinctive prognostic value of these molecular markers in HPVNs.

[Molecular and Genetic Mechanism of Three Cases of Para-Bombay Blood Group].

OBJECTIVE: To explore molecular and genetic mechanism of 3 cases of para-Bombay blood group. METHODS: The bood samples of proband and family members were selected to identify their blood groups with conventional serologic methods, and salivary components carrying the ABH antigens were detected. The coding regions of FUT1 as well as exon 6 and 7 of the ABO gene were amplified using polymerase chain reaction(PCR), and the FUT1 gene was directly sequenced. RESULTS: All the 3 cases of proband were confirmed as para-Bombay blood group. Direct sequencing revealed h new2 (nt328G→A) and h1(nt 547 ΔAG) in FUT1 gene of the proband 1, and FUT1 genotype was h1/h new2. However, the genotypes of his parents were H/h1 and H/h new2, which were non-Bombay individuals. The FUT1 genotypes of proband 2 and 3 were h1h2 (nt 547 ΔAG) and h1h2 (nt 880 ΔTT), respectively. CONCLUSION: The technology of molecular biology can be used to detect the base deletion mutations in FUT1 gene, which contributes to the analysis of molecular and genetic mechanism of para-Bombay blood group.

[Characterization of S gene of a strain of hantavirus isolated from Apodemus peninsulae in Heilongjiang Province].

In order to study the molecular characterization of the hantavirus isolated from Apodemus peninsulae in Heilongjiang Province, the S gene of a new strain NA33 was amplified, sequenced and analyzed. The results showed that the complete nucleotide sequence of the S gene of NA33 strain was composed of 1 693 nucleotides with TA-rich. The S gene contained one ORF, starting at position 37 and ending at position 1 326, encoding the N protein of 429 amino acid residues, and in line with HTN-based coding. Sequence comparison of the S genes between NA33 and reference hantavirus strains showed that NA33 was more homologous to Amur-like viruses than to the Hantaan (HTN) viruses or the other hantaviruses. Phylogenetic analysis of the amino acid sequence of N proteins showed that NA33 was clustered into the group of Amur-like viruses and was more similar to Far East Russia and Jilin strains isolated from Apodemus peninsulae. The phylogenetic tree indicated a certain degree of host-dependent characteristics and geographical aggregation characteristics of hantanviruses. Furthermore, the amino acid sequence of N protein of NA33 had the conserved amino acid sites of Amur-like viruses. In conclusion, Apodemus peninsulae carried Amur-like viruses in Heilongjiang province and was an important infectious source of hemorrhagic fever with renal syndrome (HFRS).

[Isolation and identification of A reovirus from masked civet cats (Paguma Larvata)].

192 samples of Masked Palm Civet (Paguma Larvata) from Guangdong Province were inoculated in Vero-E6 cells. One sample which came from masked palm Civet didn't cause cytopathic effects (CPE) until fourth-passage on Vero-E6 cells. Infected cells emerged granulating, shrinking, rounding and falling off. After three times freeze-thaw, cells and culture medium were harvested for electron microscopy. Virus particles were nonenveloped, double capsid and icosahedral symmetry. This virus was designated Masked Palm Civet/China/2004 (MPC/04). Hemagglutination test indicated that the virus could agglutinate healthy human type O red cells, but not the red cells of SPF chicken, experimental common bovine, rat and guinea pig. This virus was tolerant to chloroform treatment, pH 3.0 and water bath 50 degrees C 1 h. 1 M MgCl2 treatment could enhance resistance of virus to heat and increase infectivity. In order to classify the strain on the molecular level, specific primers according to mammalian reovirus were used for Reverse Transcription Polymerase Chain Reaction (RT-PCR). Appropriate specific products were amplified by RT-PCR. NCBI BLAST analysis indicated that this segment shared the highest identity to mammalian reovirus serotype 1 (T1L) virus. So we can deduce this virus is a member of the Reoviridae.

[Characteristic analysis of E protein genes of new strains of tick-borne encephalitis virus isolated from China].

In order to determine the characteristics and genotypes of E protein genes of tick-borne encephalitis (TBE) virus strains DXAL-5, 12,13,16,18, 21 isolated from Ixodes persulcatus in the Northeast of China, cDNA synthesis of E protein genes of the six DXAL strains was performed using RT-PCR, and the E protein genes were cloned and sequenced. The results showed that the nucleotide sequence of E protein gene of the six DXAL strains was 1488 bp in length respectively and the length of predicted protein was 496 aa respectively. Sequence comparison of E protein genes among the six DXAL strains and the reference TBE virus strains showed that the six DXAL strains were more homologous to Far Eastern subtype strains than to Siberian subtype strains or European subtype strains. And the majority of subtype-determining amino acid sites of the six DXAL strains belonged to TBE virus Far Eastern subtype. Phylogenetic analysis of protein E showed that the six DXAL strains were all within the clade containing Far Eastern subtype strains. The new strains had higher identities and closer phylogenetic relationships with Senzhang strain, so we speculate that this vaccine strain still have good protection against the new TBE virus isolates. In the A, B and C antigenic domains of protein E, the six DXAL strains had different degrees of amino acid changes. These mutations were likely to affect the function of E protein.