Prokaryotic Expression and Purification of the Notch Ligand and Its Effect on Hematopoiesis after Carbon Tetrachloride Damage / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To express and purify the mouse endothelial cell-targeted recombinant Notch ligand protein mD1R, and to investigate its effect on hematopoiesis after carbon tetrachloride damage.</p><p><b>METHODS</b>PCR was performed to clone and construct the expression vector pET22b(+)-mD1R. The mD1R successfully transformed into E. coli was induced by IPTG, and purified with Ni-beads affinity chromatography. The target protein was detected by SDS-PAGE. The fluorescence-activated cell sorting analysis (FACS), cell adhesion test, immunofluorescence staining and quantitative real-time PCR were employed to detect the endothelial cell-targeted and Notch signaling-activated biological characteristics of mD1R. The carbon tetrachloride mouse model was established to observe the effects of mD1R on the hematopoietic stem cell (HSC), myeloid cells and lymphoid cells by flow cytometry. The LinScal-1c-Kit cells were sorted by magnetic bead, FACS was performed to analyze the cell cycle, and RT-PCR was employed to observe the expression of interleukin (IL)-10.</p><p><b>RESULTS</b>The prokaryotic expression vector was successfully cloned and constructed. The purity and the activity were confirmed in mD1R recombinant protein. The purified mD1R activated the Notch signaling pathway of hematopoietic stem cells in carbon tetrachloride damaged mouse, and internally elevated the number of HSC and long-term HSC to 2.96-fold and 6.18-fold. In addition, mD1R improved the amplification of the myeloid progenitor cells and the myeloid-derived suppressor cells, particularly the granulocyte/monocyte into blood. Mechanistically, the further analyses suggested that Notch pathway could increase the proliferation of HSC and enhance expression of IL-10 after stress injury.</p><p><b>CONCLUSIONS</b>A new and activated recombinant Notch ligand protein has been obtained successfully to communicate hematopoietic stem cells and hematopoietic microenvironment. The Notch- mediated intrinsic hematopoiesis has been regulated by the anti-inflammatory factor after stress injury.</p>

Detection of ABL kinase domain point mutations in chronic myeloid leukemia patients receiving imatinib treatment / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the frequency and clinical significance of ABL tyrosine kinase point mutations in chronic myeloid leukemia (CML) patients receiving imatinib treatment.</p><p><b>METHODS</b>Nested reverse transcriptase-polymerase chain reaction (RT-PCR) was performed on 40 bone marrow samples from 23 patients to amplify the ABL kinase domain, followed by direct sequencing and sequence homologous analysis.</p><p><b>RESULTS</b>In the 23 patients analyzed, the ABL domain point mutations was detected in 7 patients who presented with 5 types of nucleotide changes, namely T315I(n=3), Y253H, E255K, F317L and G321W. The incidence of mutations in chronic phase (CP), accelerated phase (AP) and blast phase (BP) was 25.00%, 40.00% and 30.00%, respectively. For 6 of the 7 patients with mutations who were resistant to imatinib before sequencing, the daily drug dose had been increased to 600-800 mg daily for poor response to 400 mg/day imatinib. During the follow-up for 3-6 months, only the patient with F317L achieved major cytogenetic response (MCR), and the patient with Y253H and 1 of the 3 with T315I progressed to BP. The newly diagnosed patient with G321W IN cp achieved a complete hematologic remission and had a significant decrease of the proportion of BCR-ABL-positive cells.</p><p><b>CONCLUSIONS</b>ABL kinase point mutation is an important mechanism of imatinib resistance. The type of mutations is associated with the level of resistance to imatinib, and detection of ABL kinase point mutations by direct sequencing may help estimate the prognosis and plan for therapeutic strategy adjustment.</p>