Establishment of leukemia cell model with inducible AML1-ETO expression and its effect on fatty acid metabolism in leukemia cells / 中华血液学杂志

Objective: To investigate the effect of the AML1-ETO (AE) fusion gene on the biological function of U937 leukemia cells by establishing a leukemia cell model that induces AE fusion gene expression. Methods: The doxycycline (Dox) -dependent expression of the AE fusion gene in the U937 cell line (U937-AE) were established using a lentivirus vector system. The Cell Counting Kit 8 methods, including the PI and sidanilide induction, were used to detect cell proliferation, cell cycle-induced differentiation assays, respectively. The effect of the AE fusion gene on the biological function of U937-AE cells was preliminarily explored using transcriptome sequencing and metabonomic sequencing. Results: ①The Dox-dependent Tet-on regulatory system was successfully constructed to regulate the stable AE fusion gene expression in U937-AE cells. ②Cell proliferation slowed down and the cell proliferation rate with AE expression (3.47±0.07) was lower than AE non-expression (3.86 ± 0.05) after inducing the AE fusion gene expression for 24 h (P<0.05). The proportion of cells in the G(0)/G(1) phase in the cell cycle increased, with AE expression [ (63.45±3.10) %) ] was higher than AE non-expression [ (41.36± 9.56) %] (P<0.05). The proportion of cells expressing CD13 and CD14 decreased with the expression of AE. The AE negative group is significantly higher than the AE positive group (P<0.05). ③The enrichment analysis of the transcriptome sequencing gene set revealed significantly enriched quiescence, nuclear factor kappa-light-chain-enhancer of activated B cells, interferon-α/γ, and other inflammatory response and immune regulation signals after AE expression. ④Disorder of fatty acid metabolism of U937-AE cells occurred under the influence of AE. The concentration of the medium and short-chain fatty acid acylcarnitine metabolites decreased in cells with AE expressing, propionyl L-carnitine, wherein those with AE expression (0.46±0.13) were lower than those with AE non-expression (1.00±0.27) (P<0.05). The metabolite concentration of some long-chain fatty acid acylcarnitine increased in cells with AE expressing tetradecanoyl carnitine, wherein those with AE expression (1.26±0.01) were higher than those with AE non-expression (1.00±0.05) (P<0.05) . Conclusion: This study successfully established a leukemia cell model that can induce AE expression. The AE expression blocked the cell cycle and inhibited cell differentiation. The gene sets related to the inflammatory reactions was significantly enriched in U937-AE cells that express AE, and fatty acid metabolism was disordered.

Preparation of CD52-targeted chimeric antigen receptor-modified T cells and their anti-leukemia effects / 中华血液学杂志

Objective: To construct chimeric antigen receptor (CAR) T cells targeting CD52 (CD52 CAR-T) and validate the effect of CD52 CAR-T cells on CD52-positive leukemia. Methods: A second-generation CD52-targeting CAR bearing 4-1BB costimulatory domain was ligated into a lentiviral vector through molecular cloning. Lentivirus was prepared and packaged by 293 T cells with a four-plasmid system. Fluorescein was used to label cell surface antigens to evaluate the phenotype of CD52 CAR-T cells after infection. Flow cytometry and ELISA were used to evaluate the specific cytotoxicity of CD52 CAR-T cells to CD52-positive cell lines in vitro. Results: ①A pCDH-CD52scFv-CD8α-4-1BB-CD3ζ-GFP expressing plasmid was successfully constructed and used to transduce T cells expressing a novel CD52-targeting CAR. ②On day 6, CD52-positive T cells were almost killed by CD52-targeted CAR-T post lentivirus transduction [CD52 CAR-T (4.48 ± 4.99) %, vs Vector-T (56.58±19.8) %, P=0.011]. ③T cells transduced with the CAR targeting CD52 showed low levels of apoptosis and could be expanded long-term ex vivo. ④The CD52 CAR could promote T cell differentiation into central and effector memory T cells, whereas the proportion of T cells with a CD45RA(+) effector memory phenotype were reduced. ⑤CD52 CAR-T cells could specifically kill CD52-positive HuT78-19t cells but had no killing effect on CD52-negative MOLT4-19t cells. For CD52 CAR-T cells, the percentage of residual of HuT78-19t cells was (2.66±1.60) % at an the E:T ratio of 1∶1 for 24 h, while (56.66±5.74) % of MOLT4-19t cells survived (P<0.001) . ⑥The results of a degranulation experiment confirmed that HuT78-19t cells significantly activated CD52 CAR-T cells but not MOLT4-19t cells[ (57.34±11.25) % vs (13.06± 4.23) %, P<0.001]. ⑦CD52 CAR-T cells released more cytokines when co-cultured with HuT78-19t cells than that of vector-T cells [IFN-γ: (3706±226) pg/ml, P<0.001; TNF-α: (1732±560) pg/ml, P<0.01]. Conclusions: We successfully prepared CD52 CAR-T cells with anti-leukemia effects, which might provide the foundation for further immunotherapy.

Preparation of CD33 targeted bispecific- and trispecific-T cell engagers and their cytotoxicity on leukemia cells / 中华血液学杂志

Objective: To investigate the effect of CD33-targeted bi-specific and tri-specific T-cell engagers on T-cell proliferation and explore their cytotoxicity on leukemia cells. Methods: The CD33-targeted bi-specific T-cell engager (CD33-BiTE) and tri-specific T-cell engager (CD33-TriTE) expression vectors were successfully constructed and expressed through a eukaryotic cell expression system. CD33-BiTE and CD33-TriTE were purified by affinity chromatography. The effects of CD33-BiTE and CD33-TriTE on T cells were analyzed through in vitro experiments. Results: ① CD33-BiTE and CD33-TriTE were successfully constructed and purified and could compete with flow cytometry antibodies for binding to the target cells. ② After 12 days of co-culture with CD33-BiTE and CD33-TriTE, the number of human T cells were expanded to 33.89±19.46 and 81.56±23.62 folds, respectively. CD33-TriTE induced a stronger proliferation of T cells than CD33-BiTE (P<0.05) . ③ Both CD33-BiTE and CD33-TriTE induced specific dose-dependent cytotoxicity on CD33(+) leukemia cells. ④ Compared to CD33-TriTE, leukemia cells were prone to express PD-L1 when co-cultured with T cells and CD33-BiTE. CD33-TriTE induced powerful cytotoxicity on leukemia cells with high PD-L1 expression. Conclusion: CD33-BiTE and CD33-TriTE expression vectors were constructed, and fusion proteins were expressed in eukaryotic cells. Our results support the proliferative and activating effects of BiTE and TriTE on T cells. Compared to that of CD33-BiTE, CD33-TriTE induced a stronger proliferative effect on T cells and a more powerful cytotoxicity on leukemia cells with high PD-L1 expression.

Effects of interferon regulatory factor 9 on the biological phenotypes in PML-RARα-induced promyelocytic leukemia / 中华血液学杂志

Objective: To investigate the prognostic significance of interferon regulatory factor 9 (IRF9) expression and identify its role as a potential therapeutic target in acute promyelocytic leukemia (APL) . Methods: The gene expression profile and survival data applied in the bioinformatic analysis were obtained from The Cancer Genome Atlas and Beat acute myeloid leukemia (AML) cohorts. A dox-induced lentiviral system was used to induce the expression of PML-RARα (PR) in U937 cells, and the expression level of IRF9 in U937 cells treated with or without ATRA was examined. We then induced the expression of IRF9 in NB4, a promyelocytic leukemia cell line. In vitro studies focused on leukemic phenotypes triggered by IRF9 expression. Results: ①Bioinformatic analysis of the public database demonstrated the lowest expression of IRF9 in APL among all subtypes of AML, with lower expression associated with worse prognosis. ②We successfully established a PR-expression-inducible U937 cell line and found that IRF9 was downregulated by the PR fusion gene in APL, with undetectable expression in NB4 promyelocytic cells. ③An IRF9-inducible NB4 cell line was successfully established. The inducible expression of IRF9 promoted the differentiation of NB4 cells and had a synergistic effect with lower doses of ATRA. In addition, the inducible expression of IRF9 significantly reduced the colony formation capacity of NB4 cells. Conclusion: In this study, we found that the inducible expression of PR downregulates IRF9 and can be reversed by ATRA, suggesting a specific regulatory relationship between IRF9 and the PR fusion gene. The induction of IRF9 expression in NB4 cells can promote cell differentiation as well as reduce the colony forming ability of leukemia cells, implying an anti-leukemia effect for IRF9, which lays a biological foundation for IRF9 as a potential target for the treatment of APL.

Functional investigation of chimeric antigen receptor T cells targeting LMP1 antigen / 中华血液学杂志

Objective: This study aimed to create a type of CAR-T cells that targets LMP1 antigen and study its immunotherapeutic effect on LMP1-positive hematological malignancies. Methods: To generate LMP1 CAR-T cells, a plasmid expressing LMP1 CAR was created using molecular cloning technology, and T cells were infected with LMP1 CAR lentivirus. The effects of LMP1 CAR-T cells on specific cytotoxicity against LMP1-positive tumor cell lines infected with the EB virus had been confirmed. Results: ① LMP1 protein expressing on EB virus-positive lymphoma cells surface was verified. ② The LMP1 CAR-expressing plasmid was created, and LMP1 CAR-T cells were obtained by infecting T cells with a lentivirus packaging system, with an infection efficiency of more than 80% . ③LMP1 CAR-T cells have a 4∶1 effect-to-target ratio in killing LMP1-positive lymphoma cells. The killing effect of LMP1 CAR-T cells on Raji cells was enhanced after 48 h of coculture, but there was no significant killing effect on Ramos, which are LMP1-negative lymphoma cells. ④After coculture with LMP1-positive lymphoma cells at a ratio of 1∶1 for 5 h, the degranulation effect was enhanced. The proportion of CD107a(+) T cells in the LMP1 CAR-T cell treatment group was significantly higher than that in the vector-T cell group [ (13.25±2.94) % vs (1.55±0.05) % , t=3.972, P=0.017]. ⑤After coculture with LMP1-positive lymphoma cells, the proportion of CD69(+) and CD25(+) T cells in the LMP1 CAR-T cell group was significantly higher than that in vector-T cell group [ (7.40±0.41) % vs (3.48±0.47) % , t=6.268, P=0.003; (73.00±4.73) % vs (57.67±2.60) % , t=2.842, P=0.047]. ⑥After coculture with LMP1-positive lymphoma cells, cytokine secretion in the LMP1 CAR-T cell group was higher than that in the vector-T cell group [interferon-gamma: (703±73) ng/L vs (422±87) ng/L, t=2.478, P=0.068; tumor necrosis factor-alpha: (215±35) ng/L vs (125±2) ng/L, t=2.536, P=0.064]. Conclusion: In this study, we found that the LMP1 protein is only found on the surface of the EBV-positive tumor cell. Simultaneously, we created an LMP1 CAR-expressing plasmid and obtained LMP1 CAR-T cells by infecting T cells with a lentivirus packaging system. Furthermore, we demonstrated that LMP1 CAR-T cells could specifically kill LMP1-positive tumor cells in vitro. The degranulation and activation effects of LMP1 CAR-T cells were enhanced after coculture with LMP1-positive tumor cells, indicating a potential clinical application.

Effect of Chemotherapeutic Drug-Induced Damage of Bone Marrow Stroma Cells on Normal Hematopoietic Cells / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of damage of bone marrow stroma cells induced by chemotherapeutic drug on the function of normal hematopoitic cells.@*METHODS@#Senescence cells were detected by flow cytometry after SA-β-gal staining; real-time PCR was used to detect the expression of a serial molecules in bone marrow stromal cell line OP9 cells; the expression of γ-H2AX was determined by flow cytometry after histone γ-H2AX staining; the colony forming ability of hematopoietic cells was tested by colony formation assay.@*RESULTS@#The percentage of senescence cells in OP9 cells after DNR treatment was 2.24 times as much as that in untreated OP9 cells (P<0.05). Compared with normal OP9 cells, the expression levels of IL-6 and TNF-alpha in DNR-treated OP9 cells increased by 2.73 times (P<0.01) and 0.56 times (P<0.01), and the expression levels of N-cadherin, alpha smooth muscle actin (alpha-SMA), angiopoietin1 (Angpt1) and osteopontin (OPN) decreased by 69.54%（P<0.01），63.90%（P<0.01），87.41%（P<0.01）and 42.78%（P<0.01）respectively. After the co-culture with DNR-treated OP9 cells, the colony formation of normal hematopoietic cells decreased by 47.10% than that co-cultured with untreated OP9 cells (P< 0.05), meanwhile, the percentage of γ-H2AX+ cells in normal hematopoietic cells increased by 2.19 times (P<0.05).@*CONCLUSION@#After treatment with DNR, the senescence cell number of OP9 cells sgnificantly increases; the expression of TNF-α and IL-6 is up-regulated, while the expression of α-SMA, Angpt-1 and OPN is down-regulated as compared with normal OP9 cells. In addition, after co-culture of DNR-treated OP9 cells with normal hematopoietic cells, the colony formation ability of hematopoietic cells decreases and the genome instability of hematopoietic cells increases as compared with normal hematopoietic cells.

Oxidative Damage of Bone Marrow Stromal Cells Caused by Chemotherapy Drugs / 中国实验血液学杂志

OBJECTIVE@#To explore the oxidative damage of OP9 cells induced by daunorubicin (DNR) treatment.@*METHODS@#The TMRM probe was used to detect mitochondrial membrane potential by flow cytometry; the reactive oxygen species (ROS) was determined by flow cytometry DCFDA probe; the real-time PCR was used to detect the molecular expression of antioxidant enzyme，glutathione peroxidase (GPX) in OP9 cells; the expression of γ-H2AX was determined by flow cytometry.@*RESULTS@#Compared with normal OP9 cells, the positive rate of TMRM in DNR-treated OP9 cells decreased by 56.7% (P＜0.05); the positive rate of DCFDA in DNR-treated OP9 cells increased by 3.52 times (P＜0.01). Compared with normal OP9 cells, DNR-treated OP9 cells showed a decrease in the expression of GPX4 by 44.22% (P＜0.001); the expression of GPX7 decreased by 65.7% (P＜0.001); the expression of GPX8 decreased by 24.7% (P＜0.001); the positive rate of γ-H2AX in DNR-treated OP9 cells increased (P＜0.05).@*CONCLUSION@#After DNR treatment, mitochondrial membrane potential of OP9 cells decreases; the level of reactive oxygen species increases; the expression of glutathione peroxidase (GPX) molecules decreases significantly; genomic instability increases obviously; the oxidative damage of cells increased.

Exploration of Mechanism for Meisoindigo-Inducing K562 Cell Apoptosis by Using Quantitative Proteomic Analysis / 中国实验血液学杂志

OBJECTIVE@#To screen the differentially expressed proteins at the early stage of K562 cells treated with meisoindigo by using tandem mass tags (TMT)-based proteomics technology, and to explore the mechanism for meisoindigo-inducing apoptosis.@*METHODS@#The half inhibitory concentration (IC) of mesoindigo on K562 cells was determined by CCK8. The flow cytometry was used to assay the apoptosis of K562 cells treated by meisoindigo or DMSO. Total proteins were extracted from the cells treated with 0.2% DMSO (control) or 20 μmol/L meisoindigo (Test) for 2 hours. Then, the TMT-labeling HPLC-MS/MS was used to identify and quantify the peptides and their abundance, all the tests were repeated for 3 times. The Mascot software was used to identify the proteins; the GO annotations, enrichment and cluster analysis were used to analyze the differentially expressed proteins.@*RESULTS@#Meisoindigo-induced K562 cell apoptosis in a dose-dependent manner (r=0.98), 5 544 proteins were identified, 4792 of which were quantified. The protein with expression difference>1.5-folds in Test group accoanted for 8, out of which the expression of 4 proteins were up-regulated and 4 were down-regulated. The differentially expressed proteins mainly associated with reactive oxygen species (ROS).@*CONCLUSION@#Several proteins including DDIT4 were found to have dramatic changes in the early stage of K562 cells treated with meisoindigo by using quantitative proteomics technology. The ROS metabolic process may play important roles in meisoindigo-inducing apoptosis of K562 cells.

Expression of IFN-γ,IL-4 and IL-17A in asthmatic mice vaccinated with BCG and HepB in neonatal period / 中国病理生理杂志

AIM:To investigate the expression of IFN-γ,IL-4 and IL-17A in asthmatic mice vaccinated with bacillus Calmette-Guérin(BCG)and hepatitis B(HepB)in the neonatal period.METHODS: BALB/c mice were ran-domly divided into BGG+HepB+ovalbumin(OVA)group(B/H/O group),B/O group,H/O group,B/H group,OVA group,BCG group,HepB group and normal saline(NS)group(n=6).The mice in B/H/O group and B/H group at 0, 7 and 14 d received subcutaneous injection of 1×105CFU BCG for 3 times,while at 0 and 28 d received intramuscular in-jection of 1.5 μg HepB on the hindlimb twice.The mice in other groups were individually vaccinated with BCG or HepB. OVA sensitization and aerosol inhalation were performed to establish the asthma model.The lung tissues were collected for HE staining.Bronchoalveolar lavage fluid(BALF)and peripheral blood(PB)were collected,and the number of eosino-phils(EOS)in BALF was counted.The serum levels of IFN-γand IL-4,and the level of IL-17A in lung tissue homoge-nate were measured by ELISA.RESULTS: The pathological changes of the lung in OVA group, B/O group, B/H/O group and H/O group were observed.There were extensive inflammatory cell infiltration around the bronchus,and epithe-lial cell hypertrophy.Those in B/H/O group and H/O group were worse than those in OVA group, while those in B/O group was better than those in OVA group.Total BALF cell counts in B/H/O group,B/O group and H/O group were de-creased(P<0.05)as compared with OVA group.The BALF EOS count in B/H/O group was higher than that in B/H group,that in B/O group was higher than that in BCG group,and that in H/O group was higher than that in HepB groups (P<0.05).Compared with H/O group, OVA group and NS group, the serum IFN-γ/IL-4 ratio in HepB group was in-creased(P<0.05),and compared with B/H/O group,B/O group,OVA group and NS group,that in B/H group was al-so increased(P<0.05).Compared with OVA group, the level of IL-17A in the lung tissues of B/H/O group and B/O group was decreased(P <0.05), and compared with B/O group, that in B/H/O group was further decreased(P <0.05).CONCLUSION:Combined vaccination of BCG and HepB reduces the inflammotory responses in the lung tissues of asthmatic mice.The mechanism may be related with the decrease in the release of IL-4, the increase in IFN-γ/IL-4, and the inhibition of IL-17A expression.

Expression and Asymmetric Division of Numb in Leukemia Cell K562 Line / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the role of asymmetric division in leukemia cells through detection of expression and asymmetric division of Numb in differentiated and undifferentiated K562 cells.</p><p><b>METHODS</b>Firstly, Hemin was used to induce K562 cell differentiation, and the expression of Numb was detected by the real-time quantitative RT-PCR and flow cytometry. After K562 cells were synchronized by nocodazole, the Numb protein was labeled by immunohistochemical staining, followed by the determination of the terminally differentiated cells through confocal microscopy. The fluorescence intensity was calculated by Image J software, and the cell division pattern was analyzed on the basis of the fluorescence intensities of Numb in 2 divided daughter cells.</p><p><b>RESULTS</b>Compared with the undifferentiated K562 cells, the level of Numb mRNA expression increased 2.3 times (P<0.001). The ratio of Numb positive cells was(67.37±5.01)% in differentiated K562 cells, while that was (43.97±5.72)% in undifferentiated K562 cells (P<0.01). Compared with undifferentiated K562 cells, the ratio of cells with asymmetric division in differentiated K562 cells increased 18.3%, the percentage of cells with symmetry self-renewal reduced 49.7%(P<0.001) and that with symmetry differentiation increased 32%(P<0.001).</p><p><b>CONCLUSION</b>In differentiated K562 cells, expression of Numb and proportion of cells with asymmetric division were higher than that in undifferentiated cells. With the differentiation of leukemia cells, the proportion of cells with asymmetrical division increases, and the proportion of cells with symmetrical self-renewal decreases. The stemness of leukemia cells is maintained mainly through the symmetrical self-renewal.</p>

Functional Variant of C-689T in the Peroxisome Proliferator-Activated Receptor-γ2 Promoter is Associated with Coronary Heart Disease in Chinese Nondiabetic Han People / 中国医学科学杂志(英文版)

Objective To investigate the association between the polymorphism of C-689T in the peroxisome proliferator-activated receptor-γ2 (PPARγ2) promoter and coronary heart disease (CHD). Methods This case-controlled study was conducted in nondiabetic Chinese Han people, which enrolled 455 patients with CHD (cases) and 693 subjects without CHD (controls). Data of clinical indexes were collected, including height, body weight, waist circumstance, systolic blood pressure (SBP), diastolic blood pressure (DBP), smoking, drinking, physical activity, as well as body mass index (BMI). Fasting blood glucose (FBG), plasma total cholesterol (TC) and triglyceride (TG) levels were measured. Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) was used to determine the PPARγ2 promoter C-689→T substitution. The genotype distribution of PPARγ2 promoter C-689T, allelic frequency, clinical indexes, and laboratorial measurements were compared between the two groups. The effect of genotype on the risk of CHD was assessed using univariate and multivariate regression model. Results The genotype frequencies of CC, CT and TT in PPARγ2 promoter C-689T were 89.7%, 9.9% and 0.4% in the case group, and 93.1%, 6.6% and 0.3% in the control group, respectively (CC vs. CT+TT, χ= 6.243, P=0.041). Carriers of -689T allele (n=95) had significantly higher TC level than non-carriers (n=1053) (5.12±1.26 vs. 4.76±1.22 mmol/L, P=0.001). Male carriers of -689T allele (n=51) were significantly higher in waist circumference, body weight, TC and TG than male non-carriers (n=656) (all P<0.05). In subjects whose BMI was over 25 kg/m, carriers of -689T allele (n=82) had significantly higher levels of waist circumference, BMI, SBP and TC than non-carriers (n=231) (all p<0.05). The -689T allele was an independent risk factor for CHD (OR=1.668, 95%CI: 1.031-2.705, P=0.037) after adjusting for age, gender, waist circumference, body weight, BMI, smoking, physical activities, SBP, DBP, FBG, TC and TG level. Conclusion These data support the hypothesis that the -689T allele is associated with an increased risk of CHD, in Chinese Han people and correlates significantly with the profiles of CHD-related risk factors.

Relationship between High Expression of c-FLIP and Drug Resistance of Leukemia Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effect of c-FLIP expression on drug resistance of Kasumi-1 leukemia cells and its mechanisms.</p><p><b>METHODS</b>Tet-on inducible system was used to construct the conditional expression vector of c-FLIP by cloning the c-FLIP gene into lentivirus vector pLVX-Tight-Puro, then the Kasumi-1 cells were transfected with lentivirus pLVX-Tight-Puro-c-FLIP. The expression of c-FLIP was induced by doxycycline(Dox) for different time and doses, and verified by qRT-PCR and Western blot. On the basis of the overexpression of c-FLIP, the Kasumi-1-c-FLIP cells were treated with CH11 and PB in order to induce apoptosis, and the Giemsa staining was used to show the apoptotic cell morphology.</p><p><b>RESULTS</b>qRT-PCR and Western blot showed the overexpression of c-FLIP, the CH11 and PB can induce Kasumi-1 cell apoptosis, while the c-FLIP overexpression weakened this effects. Western blot showed that the c-FLIP blocked the caspase-8 activation.</p><p><b>CONCLUSION</b>The overexpression of c-FLIP inhibits the apoptosis caused by CH11 and PB, and leads to drug resistance in leukemia cells.</p>

Reconstruction of Humanized Bone Marrow Niche in Immunodeficiency Mouse / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To reconstruct a human bone marrow niche in immunodeficiency mouse (NOD/SCID) so as to provide a model for observing the effect of abnormal BM niche on the occurence and development of leukemia.</p><p><b>METHODS</b>Human platelet lysate(HPL) was obtained by repeated freezing and thawing of concentrated platelet. Bone marrow-derived mesenchymal stem cells were cultured in α-minimal essential medium (α-MEM) containing 10% HPL or 10% FBS. The morphology, cell phenotype, multilineage differentiation potential in vitro and proliferation capacity between the mesenchymal stem cells cultured with HPL or FBS were compared. The human bone marrow formation capacity of HPL-cultured MSC was observed. The MSC was seeded on β-TCP scaffolds for 12h, then the MSC-coated scaffold were implanted in a subcutaneous pocket on the dorsum of NOD/SCID mice. After 8-12 week, the scaffolds were harvested from the mice, then fixed, paraffin-embedded and stained for HE.</p><p><b>RESULTS</b>Whether cultured in the presence of HPL or FBS, the MSC all displayed a spindle-shaped fibroblast-like morphology; the flow cytometry analysis revealed no obvious differences in cell immunophenotype in this 2 groups; they all have the ability to differentiate towards osteoblasts, adipocytes, and chondrocytes in vitro. However, the mesenchymal stem cells cultivated with HPL-contained medium showed stronger proliferation capacity and higher activity to differentiate towards osteoblasts. Mesenchymal stem cells cultivated with HPL still have in vivo bone-forming capacity.</p><p><b>CONCLUSION</b>HPL cultured MSC have stronger proliferation capacity and potential of differentiate towards osteoblasts, HPL-cultured MSC also can reconstruct humanized bone marrow niche in murine host.</p>

Effect of TBLR1-RARα Fusion Gene on Erythroid Differentiation of K562 Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of TBLR1-RARα on the differentiation induction of leukemia cell line K562 cells into erythroid lineage and to investigate its related mechanisms.</p><p><b>METHODS</b>Tet-Off inducible system was used to construct the conditional expression vector of TBLR1-RARα fusion gene by cloning the TBLR1-RARα fragment into lentivirus vector pLVX-Tight-Puro, the expression of TBLR1-RARα fusion gene was induced by doxycycline (Dox). Then, K562 cells were transfected with lentivirus pLVX-Tight-Puro-TBLR1-RARα-flag, and the expression of fusion proteins was verified by Western blot. After treatment of K562 with all-trans retinoid acid (ATRA), real time RT-PCR was performed to test the expression of erythroid differentiation-related CD71 and α, ε, γ-globins gene. Flow cytometry was used also to analyze the expression of erythroid differentiation markers CD71 and CD235a. Benzidine staining was used to detect the production of hemoglobin in K562 cells.</p><p><b>RESULTS</b>qRT-RCR showed that ATRA could increase the expression level of CD71 and α, ε, γ-globin genes when TBLR1-RARα was expressed. After treatment of ATRA, the proportion of CD71(+) cells detected by the flow cytometry also increased. Benzidine staining showed that ATRA could induce hemoglobin production in K562 cells with TBLR1-RARα fusion gene expression.</p><p><b>CONCLUSION</b>The expression of TBLR1-RARα fusion gene contribute to ATRA-inducing differentiation of K562 cells into erythroid lineage.</p>

Determination of Th9 cells and IL-9 in children with Mycoplasma pneumoniae infection / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the clinical significance of T helper type 9 (Th9) cells and interleukin-9 (IL-9) in children suffering from Mycoplasma pneumoniae (MP) infection.</p><p><b>METHODS</b>A total of 86 children who were diagnosed with MP infection between January 2013 and June 2014 were classified into upper respiratory infection (URI) group (n=29), mild MP pneumonia (MPP) group (n=32) and severe MPP group (n=25). Twenty-eight healthy children were used as the control group. Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation, and the percentage of Th9 cells in peripheral blood was measured by flow cytometry. Serum IL-9 level was determined using ELISA.</p><p><b>RESULTS</b>The URI, mild MPP, and severe MPP groups had significantly higher percentages of Th9 cells and IL-9 levels than the control group (P<0.05); the mild MPP and severe MPP groups had significantly higher percentages of Th9 cells and IL-9 levels than the URI group (P<0.05), and the two indices were significantly higher in the severe MPP group than in the mild MPP group (P<0.01).</p><p><b>CONCLUSIONS</b>Children with MP infection have an elevated percentage of Th9 cells and IL-9 expression, both of which are positively correlated with the severity of the disease. It can be predicted that Th9 cells and IL-9 can be used as evaluation indicators for the progression and outcome of children with MP infection.</p>

Role of IFN-γ in the regulation of murine hemopoiesis / 中国实验血液学杂志

This study was aimed to explore the role and mechanism of IFN-γ in the regulation of hemopoiesis in mice. Murine IFN-γ fragment was amplified from murine splenic cells with RT-PCR and plasmid pCDH1-mIFN-γ-EF1-copGFP (pCDH-mIFN-γ-GFP) was constructed. Plasmids pCDH-mIFN-γ-GFP and pCDH1-EF1-copGFP (pCDH-GFP) together with packaging plasmids pPACK-A, pPACK-B and pPACK-C were respectively transfected into 293T cells by using a method of calcium phosphate precipitation to produce lentivirus. Bone marrow mononuclear cells (BMMNC) from male C57BL/6J mice were transfected with the lentiviral vector pCDH expressing mIFN-γ and green fluorescent protein (GFP). The cells were cultured in M3434 semi-solid medium for colony formation assay and transplanted into lethally-irradiated mice through caudal vein injection, and the peripheral blood cell counts and GFP were monitored regularly after transplantation. The results showed that lentiviral vector pCDH-mIFN-γ-GFP was constructed successfully and 293T cells transfected with mIFN-γ secreted mIFN-γ. Transfection of mIFN-γ into BMMNC decreased colony formation, colony number of the mIFN-γ group was significantly less than that of the control group. The recovering of circulating blood cell parameters in mIFN-γ transplantation group was significantly later than control group. GFP positive cells could be detected in the peripheral blood at 8 weeks after transplantation. It is concluded that mIFN-γ may inhibit the colony-forming capacity of transduced BMMNC and delay the hematopoietic reconstitution.

Dexamethasone and vorinostat cooperatively promote differentiation and apoptosis in Kasumi-1 leukemia cells through ubiquitination and degradation of AML1-ETO / 中华血液学杂志

<p><b>OBJECTIVE</b>To probe the effects of dexamethasone (DEX) combined with histone deacetylase (HDAC) inhibitor vorinostat on inhibiting proliferation and inducing differentiation and apoptosis in Kasumi-1 leukemia cells, and its possible mechanisms in order to provide a theoretical basis for the treatment of AML1-ETO positive AML.</p><p><b>METHODS</b>The cell survival, differentiation and apoptosis rates were tested by MTT or flow cytometry analysis after Kasumi-1 cells were treated by DMSO, DEX (20 nmol/L), vorinostat (1 μmol/L) or DEX (20 nmol/L) in combination with vorinostat (1 μmol/L). WB and IP-WB were performed to detect AML1-ETO and its ubiquitination.</p><p><b>RESULTS</b>Treatment with the combination of DEX and vorinostat for 48 h led to statistically significant differences of inhibited proliferation [(42.06±8.20)%], increased differentiation [(52.83±8.97)%] and apoptosis [(52.92±2.53)%] of Kasumi-1 cells when compared with vorinostat [(33.82±9.41)%, (43.93±9.04)% and (42.98±3.01)%, respectively], DEX [(17.30±3.49)%, (22.53±4.51)% and (19.57±2.17)%, respectively] or control [(6.96±0.39)%, (21.73±2.03)% and (6.96±0.39)%, respectively]. Also significant ubiquitination and decreased AML1-ETO protein in Kasumi-1 cells after the combination treatment over single agent or control were observed.</p><p><b>CONCLUSION</b>The results indicated that DEX and vorinostat could synergistically inhibit the Kasumi-1 cells proliferation, induce Kasumi-1 cells differentiation and apoptosis through ubiquitination and degradation of AML1-ETO.</p>

Effects of transcription factor GATA-2 on transcriptive regulation of iASPP gene / 中国实验血液学杂志

iASPP can prompt the cell proliferation and inhibit the apoptosis of many cells. There are putative binding sites of transcription factor GATA-2 upstream of iASPP transcription start site. GATA-2 plays an important role in the proliferation and differentiation of hematopoietic stem cells (HSC) and progenitors. This study was aimed to explore the role of GATA-2 protein in iASPP gene transcription. Firstly, the expression of iASPP and GATA-2 protein in some leukemia cell lines was detected by Western blot. Second, The expressive vector of pCMV5-GATA2 and the luciferase reporter vectors containing possible binding sites of GATA-2 were constructed and co-transfected into HEK293 and CV-1 cells. Then the luciferase activity was assayed by luminometer. Also, ChIP assays were performed to further confirm the specific binding of GATA-2 to iASPP promoter. The results showed that GATA-2 was overexpressed in most cell lines with high level of iASPP. GATA-2 exhibited a significant effect on luciferase activity of reporter gene iASPP and in a dose-dependant manner. The relative luciferase activity was up-regulated to about two-fold of the empty vector control when the transfection dose of pCMV5-GATA2 plasmid was increased to 100 ng. While the effect was more significant in CV-1 cells and showed a 6.7-fold increase. The ChIP assay demonstrated the in vivo specific binding of GATA-2 to iASPP. The binding sites of GATA2 were located between nt -361 ∼ -334 in upstream of iASPP gene transcription start site. It is concluded that transcription factor GATA-2 can bind with the cis-regulatory region of the iASPP promoter and up-regulate iASPP expression.

Expression of c-MPL in leukemic stem cells from acute myeloid leukemia patients / 中国实验血液学杂志

This study was aimed to investigate the expression of c-MPL in acute myeloid leukemia (AML) and the correlation of the c-MPL expression with CD34 and CD38, so as to define the expression of c-MPL in leukemic stem cells. The expression levels of CD34, CD38 and c-MPL were detected by flow cytometry in bone marrow cells from 29 newly diagnosed AML patients. The relationship of c-MPL positive cell ratio with clinical parameters and correlation of c-MPL with CD34 and CD38 expression in AML patients were analyzed. The results showed that expression level of c-MPL in AML patients was significantly higher than that of normal controls (P < 0.05), and the expression level of c-MPL did not correlate with age, sex, white blood cell count, AML1-ETO fusion gene and remission after chemotherapy, but the expression of c-MPL in M2 and M5 patients was higher than that of normal control (P < 0.05). Expression of c-MPL in CD34 positive AML patients was obviously higher than that in CD34 negative AML patients (P < 0.01). c-MPL was significantly higher expressed in CD34(+) cells than that in CD34(-) cells (P < 0.001), while c-MPL expression was not significantly different between CD34(+)CD38(-) and CD34(+)CD38(-) cell groups. Positive correlation between c-MPL and CD34 expression was observed (r = 0.380, P = 0.042). It is concluded that expression of c-MPL is higher in AML patients, and positively correlates with the expression level of CD34. The c-MPL expresses in leukemic stem cells.

Effect of cyclophosphamide on murine bone marrow hematopoietic cells and its possible mechanism / 中国实验血液学杂志

This study was purposed to investigate the effect of chemotherapeutic drug cyclophosphamide (CTX) on normal murine bone marrow hematopoietic cells, especially on the self-renewal, proliferation and differentiation of bone marrow hematopoietic cells, and possible mechanisms. The CTX-treated mouse model was established by CTX 200 mg/kg, ip. The exact time of complete recovery of hematopoiesis was determined by monitoring the recovery level of differential blood counts and the proportion of LKS(+) cells in bone marrow cells. The function of bone marrow hematopoietic cells such as self-renewal, proliferation and differentiation were assessed by non-competitive and competitive bone marrow transplantation. The potential effect of CTX on senescence of bone marrow hematopoietic cells was analyzed by detecting p16(Ink4a) mRNA relative expression and SA-β-galactosidase (gal) staining. The results showed that the CTX could induce long-term but latent damage to bone marrow hematopoietic cell function and lead to the decrease in competency of bone marrow hematopoietic cells to reconstitute while seemingly permitting a complete recovery. Furthermore, the serial-transplantation model showed that these mice received transplantation of bone marrow hematopoietic cells from CTX-treated mice exhibited a high expression of p16(Ink4a) mRNA and SA-β-gal staining. It is concluded that CTX-induced bone marrow cellular senescence may play an important role in CTX-induced long-term injury to bone marrow hematopoietic cells.