Effect of Recombinant Protein in the Spacer Domain on ADAMTS13 Activity / 中国实验血液学杂志

OBJECTIVE@#To obtain the recombinant protein of spacer domain in von Willebrand factor cleaving protease (ADAMTS13), and further study its biological function in ADAMTS13.@*METHODS@#The prokaryotic expression vector was constructed by using the template of plasmid with full-length ADAMTS13, and then transfected into E coli., following the induction of IPTG with the low temperature (30 ℃). The recombinant protein was purified with Ni-NTA agarose column by gradient imidazole. The purity and immune activity of purified products were identified with SDS-PAGE and Western blot respectively. By Adding the recombinant protein to the plasma of immune-mediated thrombotic thrombocytopenic purpura (iTTP) patients, the activity of ADAMTS13 was tested.@*RESULTS@#The prokaryotic expression vector was successfully constructed and the protein of spacer domain with the high purity was obtained. Western blot showed that the recombinant fragment could both react with monoclonal antibody against 6×His and polyclonal sheep IgG against ADAMTS13 (Gln34-Trp688). The protein formed a main lane at the position of 15 kDa with SDS-PAGE. It was demonstrated that the recombinant protein could efficiently elevate the ADAMTS13 activity in plasma of iTTP patients to reach normal level by functional experiment.@*CONCLUSION@#The recombinant protein has high purity and immune activity, which provides the experimental basis for further research on mechanism of iTTP involved in spacer domain.

Development of Hybridoma Cell Lines Secreting Monoclonal Antibodies against ADAMTS13 / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To establish the hybridoma cell lines secreting anti-ADAMTS13-T7 monoclonal antibodies (MA6) and to construct the MAb directed against different domains of ADAMTS13-T7.</p><p><b>METHODS</b>The trucated type protein ADAMTS13 of eukaryote-expressed recombinant ADAMTS13-T7 was constructed and was purified by using Ni-NTA agarose. Then the purified ADAMTS13 was used to immunize the BALB/c mice; the antiserum titer of ADAMTS13 protein of immunized mice was deteceted by ELISA. The spleen was taken from mice for construcing the single cell suspension, then the single cell suspension was mixed with myeloma cells SP2/0 at 10:1 ratio for cell fusion, and the elution culture of hybridoma cells was carried out; after 2 weeks, the wells in which clones were well grown were selected for detection, then the positive clonal wells were expansively cultured and the detection again was performed.</p><p><b>RESULTS</b>The purified ADAMTS13-T7 protein was gained. The ELISA showed that the antiserum titer in mice immumized by ADAMTS13-T7 protein was 1:20000. The results of fusion culture by hybridoma techmique showed that 30 hyridoma cell lines secreting MAb against recombinant ADAMTS13 were established.</p><p><b>CONCLUSION</b>The hybridoma cell lines secreting MAb against recombinant ADAMTS13 have been successfully established by fusion culture, which provide more powerful tools for further screening the MAb with certain functional activity and studying the structure and function of ADAMTS13.</p>

Identification of Monoclonal Antibodies against von Willebrand Factor Cleaving Protease (ADAMTS13) and Their Function / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To construct and identify the monoclonal antibodies against von willebrand factor cleaving protease(ADAMTS13), and to study their biological function.</p><p><b>METHODS</b>BALB/c mice were immunized by purified recombinant ADAMTS13 truncated eukaryotic protein (ADAMTS13-T7). Murine anti-human ADAMTS13 monoclonal antibodies (McAbs) were constructed by standard hybridoma technology and identified by ELISA. The recognition of McAbs with full-length recombinant ADAMTS13 protein was identified by Western blot. In function assay, the influence of McAbs on the proteolysis of vWF by ADAMTS13 was observed.</p><p><b>RESULTS</b>A group of 6 murine anti-ADAMTS13 McAbs was obtained with the clone number 1G11, 2F11, 6G3, 9E1, 10A8 and 10B4. In ELISA, the highest titers of 1G11 and 2F11 were observed, both of which showed a higher affinity to ADAMTS13-T7 than full-length ADAMTS13. The Western blot demonstrated that the 6 McAbs all could recognize ADAMTS13, among which 1G11 and 2F11 showed stronger reaction with ADAMTS13. In addition, under the denatured conditions, 1G11 and 2F11 could inhibit hydrolysis of vWF by ADAMTS13, and that was stronger with the increasing of McAbs concentration.</p><p><b>CONCLUSION</b>McAbs against ADAMTS13 have been gained, two of which are inhibitory antibodies.</p>

Histopathological classification and location of consecutively operated meningiomas at a single institution in China from 2001 to 2010 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Meningioma is one of the most common primary tumors of the central nervous system, but there are not many detailed studies on the sex, age, subtypes and locations of large series. This study was a retrospective analysis of the characteristics of meningioma cases consecutively operated on at a single institution in China from 2001 to 2010.</p><p><b>METHODS</b>This study investigated the demographic background of 7084 meningioma cases, and the subtypes and locations of the tumors. Sex and age distributions were analyzed, and the pathological subtypes were classified according to the World Health Organization (WHO) classification. The location of the meningiomas was also categorized.</p><p><b>RESULTS</b>The female:male ratio of the 7084 cases was 2.34:1. The mean age was 51.4 years (range, 11 months-86 years). The mean age of cases of WHO grade I meningioma was significantly older than that of grade II or III meningiomas (P < 0.001, Fisher's Least Significant Digit test). There was a significantly higher female:male ratio in WHO grade I meningiomas than in grade II or grade III meningiomas (2.57, 1.03 and 0.76, respectively; P < 0.001, χ(2) test). Meningothelial (n = 2061) and fibrous meningiomas (n = 3556) were the most common subtypes, comprising 79.3% of all meningiomas. All meningioma cases were classified into 23 locations in this study, with the cerebral convexity the most common site (38.33%, n = 2722). Cases with uncommon locations such as extra-cranial and sylvian fissure meningiomas were also present in this series.</p><p><b>CONCLUSIONS</b>Female predominance was found for benign meningiomas, while malignant subtypes showed male predominance. The mean age of patients with WHO grade I meningiomas was older than that of patients with higher-grade tumors. Meningothelial and fibrous meningiomas were the most common subtypes. The cerebral convexity was the most common meningioma location.</p>

Reprogramming of adult human neural stem cells into induced pluripotent stem cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Since an effective method for generating induced pluripotent stem cells (iPSCs) from human neural stem cells (hNSCs) can offer us a promising tool for studying brain diseases, here we reported direct reprogramming of adult hNSCs into iPSCs by retroviral transduction of four defined factors.</p><p><b>METHODS</b>NSCs were successfully isolated and cultured from the hippocampus tissue of epilepsy patients. When combined with four factors (OCT3/4, SOX2, KLF4, and c-MYC), iPSCs colonies were successfully obtained.</p><p><b>RESULTS</b>Morphological characterization and specific genetic expression confirmed that these hNSCs-derived iPSCs showed embryonic stem cells-like properties, which include the ability to differentiate into all three germ layers both in vitro and in vivo.</p><p><b>CONCLUSION</b>Our method would be useful for generating human iPSCs from NSCs and provide an important tool for studying neurological diseases.</p>

Preoperative surgical planning for intracranial meningioma resection by virtual reality / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The Dextroscope system by Volume Interactions (Singapore) had been applied to minimally invasive neurosurgery in many units. This system enables the neurosurgeon to interact intuitively with the three-dimensional graphics in a direct manner resembling the way one communicates with the real objects. In the paper, we explored its values in pre-operation surgical planning for intracranial meningiomas resection.</p><p><b>METHODS</b>Brain computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance venography (MRV) were performed on 10 patients with parasagittal and falcine meningiomas located on central groove area; brain CT, MRI and magnetic resonance angiography (MRA) were performed on 10 patients with anterior skull base meningiomas and 10 patients with sphenoid ridge meningiomas. All these data were transferred to Dextroscope virtual reality system, and reconstructed. Then meningiomas, skull base, brain tissue, drainage vein and cerebral arteries were displayed within the system, and their anatomic relationships were evaluated. Also, the simulation operations were performed.</p><p><b>RESULTS</b>For parasagittal and falcine meningiomas, the relationships of tumor with drainage vein and superior sagittal sinus were clearly displayed in the Dextroscope system. For anterior skull base and sphenoid ridge meningiomas, the relationships of tumor with bilateral internal carotid arteries, anterior cerebral arteries, middle cerebral arteries and skull base were vividly displayed within the virtual reality system. Surgical planning and simulation operation of all cases were performed as well. The real operations of all patients were conducted according to the simulation with well outcomes.</p><p><b>CONCLUSIONS</b>According to the virtual reality planning, neurosurgeons could get more anatomic information about meningioma and its surrounding structures, especially important vessels, and choose the best approach for tumor resection, which would lead to better prognosis for patients.</p>

The effect of bortezomib on migration of endothelial cells and angiogenesis / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of bortezomib on the migration of endothelial cells and the expression of angiogenesis-related molecules, and explore the mechanism of its antiproliferation of tumor cells.</p><p><b>METHODS</b>Cell count kit CCK-8 was used to detect the relative proliferation activity of cells after treated by bortezomib at different concentrations for 12 h and 24 h, respectively. Transwell model was uesd to detect the migration rate of cells. Expression levels of VEGF and Annexin A2 genes were determined by real-time quantitative PCR. Annexin A2 protein was validated by Western blot.</p><p><b>RESULTS</b>After treated with bortezomib at concentrations of 2.5, 5.0 and 10 nmol/L for 12h, respectively, the HMEC-1 cell proliferation activity was 1.004 ± 0.002, 0.793 ± 0.021 and 0.874 ± 0.062, respectively, being no statistical difference from that of control group (1.000) P < 0.05); while the migration rates of them were 0.697 ± 0.060, 0.597 ± 0.090 and 0.874 ± 0.062, respectively, being significantly lower than that of control group (1.000) (P < 0.05) and so did for the expression of VEGF and Annexin A2 genes. After treated with 5 nmol/L bortezomib for 12 h, the Annexin A2 and VEGF gene relative expression level of HMEC-1 cells was 0.540 ± 0.001 and 0.793 ± 0.153, respectively, being of statistical difference from that of control group (1.000) P < 0.05). The conspicuous downregulation of Annexin A2 protein was also confirmed by Western Blot.</p><p><b>CONCLUSIONS</b>Bortezomib can inhibit migration of endothelial cell HMEC-1 by downregulating the expression of VEGF and Annexin A2, displaying a new mechanism of bortezomib for inhibition of tumor proliferation.</p>

Effect of bortezomib on VEGF gene expression of endothelial cell line HMEC-1 and its possible mechanisms / 中国实验血液学杂志

This study was aimed to investigate the effects of bortezomib on VEGF gene expression of endothelial cell line HMEC-1, and to determine the changes of the transcriptional regulation activity of hypoxia-inducible factor 1 (HIF-1alpha) and expression intensity of Annexin A2, so as to analyze the possible mechanisms of the above expression of VEGF gene. Expression intensity of VEGF gene was determined by real-time quantitative PCR; the relative proliferation activity of cells was assayed by cell count kit CCK-8; the expression intensity of carbonic anhydrase IX (CA IX) gene was detected by RT-PCR; expression of Annexin A2 at gene and protein levels were determined by real-time quantitative PCR and Western blot respectively. The results showed that after being treated by bortezomib with 2.5, 5.0, 10 nmol/L for 12 hours, the expression intensity of VEGF gene of endothelial cell line HMEC-1 was as follows: 0.730 +/- 0.106, 0.673 +/- 0.153, 0.767 +/- 0.090 (as 1.0 was made in 0 nmol/L) (p < 0.05); the proliferation activity of cells was not significantly suppressed by bortezomib in 2.5, 5.0 nmol/L (p > 0.05), while that was significantly suppressed by bortezomib of 10 nmol/L (p = 0.024), The results from RT-PCR showed that expression intensity of CA IX gene was conspicuously down-regulated by bortezomib in different concentrations, which suggested that the transcriptional regulation activity of HIF-1alpha was inhibited by bortezomib. And down-regulated expression of Annexin A2 protein by bortezomib in different concentrations was confirmed by real-time quantitative PCR and Western blot. It is concluded that low doses of bortezomib has no significant inhibition effect on the activity of proteasome. Bortezomib may down-regulate the expression of VEGF gene of endothelial cell through regulating the activity of HIF-1alpha and the expression of Annexin A2.

Effects of Annexin II gene silencing by siRNA on proliferation and invasive potential of Jurkat lymphoma cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of Annexin II (AnxA2) gene silencing by siRNA on proliferation and invasive potential of lymphoma cell line Jurkat cells.</p><p><b>METHODS</b>A synthesized siRNA duplex targeting to AnxA2 was transfected into Jurkat cells. Transfection efficiency was analyzed by real-time PCR and flow cytometry. MTT assay for cell proliferation and transwell plates for invasive potential were performed.</p><p><b>RESULTS</b>Compared with the negative controls, the cell proliferation inhibitory rate of the AnxA2 siRNA transfected Jurkat cells was significantly increased at 24 h, 48 h and 72 h [(17.4 +/- 2.3)%, (22.4 +/- 3.8)%, (37.6 +/- 1.5)% vs (-1.3 +/- 5.1)%, (-5.5 +/- 4.4)%, (-10.8 +/- 5.5)%, respectively, P<0.05]. The cell invasive potential of the transfected Jurkat cells was inhibited remarkably at 48 h (11.3 +/- 4.2 vs 54.3 +/- 8.7, P<0.01).</p><p><b>CONCLUSION</b>AnxA2 gene silenced by siRNA can inhibit the proliferation and the invasive potential of Jurkat cells remarkably.</p>

Characterization and functional studies of vWF A3 domain monoclonal antibodies that inhibit binding of vWF to collagen / 中华血液学杂志

<p><b>OBJECTIVE</b>To prepare anti-von Willebrand factor A3 (vWF-A3) domain monoclonal antibodies(mAbs) which block vWF-A3 binding to collagen, and characterize their biochemical properties and functions.</p><p><b>METHODS</b>BALB/c mice were immunized with purified recombinant vWF-A3 protein (rvWF-A3). Murine anti-human vWF-A3 mAbs were developed by standard hybridoma technology and identified with ELISA. The recognition of the mAbs with rvWF -A3 and reduced human vWF was identified by Western-blot. The effect of mAbs on binding of purified human vWF to human placenta or calf skin collagen III was studied with collagen binding inhibition test.</p><p><b>RESULTS</b>A group of 30 murine anti-human vWF-A3 mAbs was obtained, from which 2 clones were identified as inhibitory ones and designated as SZ-123 and SZ-125. SZ-123 and SZ-125 could react specifically with human vWF and rvWF-A3 respectively, while neither of them reacted with rvWF-A1 and rvWF-A2. Western-blot showed that SZ-123 and SZ-125 could recognize a 27 x 10(3) band of rvWF-A3 and 2 reduced human vWF bands at 250 x 10(3) and 170 x 10(3). SZ-123 and SZ-125 not only inhibited the binding of purified human vWF (1.5 and 3.0 microg/ml) to human type III collagen and to calf skin collagen III in a dose dependent manner, but also inhibited the binding of plasma vWF from human, rhesus monkeys or Beagle dogs to the two collagens.</p><p><b>CONCLUSION</b>SZ-123 and SZ-125 are neutralizing mAbs against vWF-A3 domain and may have therapeutic potential as an antithrombotic agent.</p>

Effect of Mer overexpression on HMEC-1 cell angiogenesis and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore anti-angiogenesis effect of Mer, a member of tyrosine kinase receptor family, and its mechanism.</p><p><b>METHODS</b>Human Mer full length plasmid was transfected into HMEC-1 cells through liposome. G418 was used to select positive clone. Expression of Mer at mRNA and protein level was detected by real-time PCR and Western-blot, respectively. Transwell and Matrigel were used to evaluate the effect of overexpressed Mer on migration and angiogenesis of HMEC-1 cells. Primary angiogenesis associated factor VEGF-A, VEGF-B, VEGF-C, VEGF-D and VEGFR-1, VEGFR-2 were screened by real-time PCR.</p><p><b>RESULTS</b>After G418 selection, the Mer expression in transfected HMEC-1 cells was increased 3.61- and 2.12 fold at mRNA and protein level, respectively. Compared with negative control, the migration of Mer-HMEC-1 was decreased (21 +/- 6 vs 36 +/- 11), and angiogenesis capability on Matrigel significantly decreased. By real-time PCR, the expression of VEGF-C and VEGFR-2 was down-regulated to 44.7% and 25.6% of the negative control.</p><p><b>CONCLUSION</b>Overexpressed Mer tyrosine kinase receptor can inhibit the migration and angiogenesis of HMEC-1 cells through VEGF-C/VEGFR-2 signal pathway.</p>