[Caspase1 Inhibitor Ac-YVAD-CMK Prevents and Treats the Acute Graft Versus Host Disease in Mice].

OBJECTIVE: To explore the effect of Caspase 1 inhibitor Ac-YVAD-CMK on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation(allo-HSCT) and its mechanism. METHODS: Experiments were divided randomly into 3 groups: allogeneic hematopoietic stem cell transplantation combined with splenic cell infusion group (TS group, n=12), allogeneic hematopoietic stem cell transplantation combined with splenic cell infusion plus injection of low dose Caspase 1 inhibitor group (TS+low dose of C group, n=16) and plus high dose Caspase1 inhibitor (TS+high dose of C group, n=19). The body weight of mice in each group was dynamically detected, and the clinical manifestation of GVHD and score of aGVHD were determined, and the chimerism rate of mice was detected after transplantation for 14 days. Th1, Th2 and Th17 cells in peripheral blood were examined by flow cytometry. Peripheral proinflammatory cytokines IL-1ß, IFN-γ, IL-1α and IL-18 were examined by enzyme-linked immunosorbent assay(ELISA). The tissues sections of GVHD target organs (liver, lung, colon and skin) were stained with HE for histopathologic examination and histopathologic score. RESULTS: Ac-YVAD-CMK could alleviate murine aGVHD and pathological injury, decreare the incidence and severity of aGVHD in recipient mice. The detection of Th cell subsets in peripheral blood by flow cytometry showed that compared with TS group, the Th1 cell ratio in TS+low dose of C and TS+high dose of C groups was significantly reduced (P<0.05), while the Th2 and Th17 cell ratio was significantly enhanced (P<0.05) in TS+low dose of high dose of C groups. The detection of peripheral inflamematory cytokines by ELISA demonstrated that the inflammatory cytokines including IL-1ß,IFN-γ,IL-18 and IL-1α were reduced significantly (P<0.05). CONCLUSION: Ac-YVAD-CMK can improve aGVHD by inhibiting Caspase 1 and reducing the release of some inflammatory cytokines, thereby alleviated the aGVHD pathological damage.

Effects of bone marrow mesenchymal stem cells on hematopoietic recovery and acute graft-versus-host disease in murine allogeneic umbilical cord blood transplantation model.

To investigate the effect of bone marrow mesenchymal stem cells (MSC) on hematopoietic recovery and acute graft-versus-host disease (GVHD) in a murine allogeneic umbilical cord blood transplantation (allo-UCBT) model. MSCs were obtained from C57/BL mouse bone marrow. The MSC phenotypes were identified by flow cytometry (FCM), and their ability to differentiate into osteoblasts and adipocytes was tested. Once murine allo-UCBT and aGVHD models were established, mice were divided into five groups: (1) total body irradiation (TBI) group, each mouse receiving 0.3 ml sterile saline infusion after TBI and used as control; (2) UCB group, receiving 2 × 10(6) umbilical cord blood mononuclear cells (UCB-MNC) after TBI; (3) UCB+MSC group, receiving 2 × 10(6) UCB-MNC and 2 × 10(7) MSC after TBI; (4) UCB+SC group, receiving 2 × 10(6) UCB-MNC and 2 × 10(6) spleen cells after TBI; and (5) UCB+SC+MSC group, receiving 2 × 10(6) UCB-MNC, 2 × 10(7) MSC and 2 × 10(6) spleen cells after TBI. To evaluate the engraftment of HSC, the white blood cells, red blood cells, and platelets counts were tested at different time points after transplantation, and the ratio of chimerism was identified by FCM. The acute GVHD clinical scores, recipient mice survival, and the histopathological analyses were used to evaluate the effect of MSC on acute GVHD. MSCs were successfully obtained in vitro and FCM analysis showed that these cells are highly positive for CD90.2, CD44, and negative for CD34, CD45, and they are capable to differentiate into osteoblasts and adipocytes after being induced. Compared to UCB group, the UCB+MSC mice had shorter duration of myelosuppression and higher percentage of donor-derived cells which was up to 22.87 ± 4.3 % and the white blood cell (WBC), red blood cell (RBC), and platelet counts started to increase by day 6 after transplantation. Moreover, the average survival time for UCB+MSC mice was 25.0 ± 10.55 days, while for the UCB group it was 15.5 ± 12.50 days. The UCB+SC mice showed fatigue, loss of appetite, weight loss, arched back, and hair ruffling on day 13 post transplantation. Approximately 50 % of mice showed skin ulcers, had diarrhea and other manifestations of acute GVHD, and all mice were died within 20 days. Histopathological analysis confirmed grade II-IV GVHD manifestation. In addition to transient weight loss, some UCB+SC+MSC mice developed arched back, hair ruffling, diarrhea and other manifestations of acute GVHD. The clinical scores in UCB+SC+MSC mice with acute GVHD (grade I-II or without GVHD) were lower than UCB+SC group (P < 0.05). Bone marrow MSCs can promote hematopoietic recovery and decrease the incidence of acute GVHD in murine allo-UCBT model.

[Effect of interfering the ß-catenin by lentiviral vector-mediated RNAi on the biological behavior of mouse bone marrow mesenchymal stem cells].

This study was aimed to investigate the effect of Wnt/ß-catenin signaling pathway on the biologic behavior of mouse bone marrow mesenchymal stem cells (mBM-MSC) by constructing a RNAi lentiviral vector specific to ß-catenin. Three pairs of shRNA coding sequences directed against different sites of ß-catenin mRNA were designed and were linked into lentiviral vector plasmid PLB for constructing the PLB-ß-catenin/shRNA1, PLB-ß-catenin/shRNA2 and PLB-ß-catenin/ shRNA3. Those plasmids and lentiviral packaging plasmids were co-transfected into the packaging cells 293FT, then the virus particles were collected and the viral titer was assayed after concentration, and these viral particles were infected to MSC. The flow cytometry was used to sort GFP (+) cells, Western blot and RT-PCR were used to verify the inhibitory effect of those cells on expression of ß-catenin gene in cells, CCK-8 method was used to detect the cell proliferation level, Annexin-V/7-AAD was used to determine the cell apoptosis after interference, the cell scratch and transwell tests were used to detect the migration capability of MSC. The results showed that the efficient inhibition of ß-catenin mRNA and protein expression, and the suppression of MSC proliferation were observed in group of PLB-ß-catenin/shRNA2 (interference group), while there was no significant changes of MSC proliferation between negative group (PLB group) and the normal group (control group). The flow cytometric detection indicated that after induced by serum starvation for 72 h, the apoptosis of MSC increased in interference group, but there was no difference between PLB and control groups (P > 0.05). The cell scratch and transwell tests demonstrated that the migration capability of MSC in interference group decreased significantly, while the migration capability of MSC in control group was not changed obviously. It is concluded that the constructed specific RNAi lentivirus can effectively inhibit the expression of ß-catenin gene, decrease expression level of ß-catenin mRNA and protein. The Wnt/ß-catenin signaling pathway plays an important role in biological behavior of BM-MSC.

[Effects of immature dendritic cells to express CCR7 on graft-versus-host disease in allogeneic bone marrow transplant mouse model].

OBJECTIVE: To investigate the effects of immature dendritic cells (imDC) expressing chemokine receptor-7 (CCR7) on acute graft-versus-host disease (aGVHD) in allogeneic bone marrow transposed (allo-BMT) mouse model. METHODS: We constructed the lentiviral vectors carrying mouse CCR7 gene and infect imDC effectively in vitro. GVHD model was established with C57BL/6(H-2b) donor mice and BALB/c (H-2d) recipient mice. After irradiation, recipients were injected with donor bone marrow and spleen cells along with CCR7-modified dendritic cells. Mice were randomized into irradiation, transplant control, pXZ9-imDC (empty vector control) and CCR7-imDC groups. Survival, GVHD score, histopathological analysis and plasma levels of inflammatory cytokines were observed. RESULTS: The mean survival in irradiation, transplantation, pXZ9-imDC and CCR7-imDC groups were (8.20±1.48)d, (12.20±2.78)d, (20.70±6.01)d and (27.5±7.55)d respectively. The survival in CCR7- imDC group was significantly improved compared with other groups (P<0.05). GVHD scores in transplantation, pXZ9-imDC and CCR7-imDC groups were (6.90±1.66), (5.60±0.97) and (4.10±1.79) respectively. CCR7-imDC group had significantly lower GVHD score and minor tissue damages shown by histopathological analysis than the other groups. Plasma IFN-γ level increased and reached the peak at +10 day in transplant group, while it gradually decreased in pXZ9-imDC and CCR7-imDC groups, and then reached the nadir at +20 day post-allo-BMT, with the lowest level in CCR7-imDC group (P<0.01). Plasma IL-4 decreased in transplant group, while it gradually increased in pXZ9-imDC and CCR7-imDC groups and reached the highest level at + 10 day in CCR7- imDC group (P<0.01). The 95%-100% of H-2b positive cells in recipient mice on + 30 day post-allo-BMT demonstrated the complete donor- type implantation. CONCLUSION: Genetically modified immature DC by CCR7 gene could alleviate damages by GVHD and prolong survival of recipient mice after allo-BMT.

[Construction of shRNA expression vector targeting AATF and establishment of stably transfected U937 cells].

This study was aimed to construct the targeting AATF shRNA eukaryotic expression vector and establish the stably transfected U937 cell lines. The sequence of AATF mRNA was obtained from GenBank. After excluding homology, three plasmid expression vectors coding shRNA targeting 228 ∼ 249, 303 ∼ 324 and 443 ∼ 464 of AATF gene sequence were synthesized. Two terminals of shRNA carried BamHI and HindIII restriction sites. The selected nucleotides were cloned into the plasmid pSilencer 3.1-H1 neo respectively, and the resultant recombinant plasmids were named as pSA-1, pSA-2, pSA-3. The sequences of the recombinant plasmids were identified by DNA sequencing. The recombinant plasmids were transfected into the cell line U937 by electroporation with Neon(TM) Transfection System. The transfected cells were persistently screened under G418 (500 mg/L), and isolated with a limited dilution for 8 weeks. The inhibition of AATF mRNA and protein expression was respectively detected by RT-PCR and Western blot. The results indicated that RNAi eukaryotic expression vectors targeting AATF had correct reading frame and nucleotide sequence. Real-time PCR revealed that AATF shRNA effectively silenced mRNA expression of AATF. Western blot analysis found that AATF shRNA obviously suppressed protein expression of AATF (P < 0.05). It is concluded that the shRNA eukaryotic expression vector has been successfully constructed which can inhibit the expression of AATF, and the establishment of stably transfected U937 cell lines provide a original route for exploring the mechanism of AATF in human Leukemia further.

[Effect of different therapeutic regimens on regulatory T cells in patients of primary immune thrombocytopenia].

OBJECTIVE: To investigate the change of CD4⁺CD25(high)CD127(low) regulatory T cells (Tregs) percentage in patients with primary immune thrombocytopenia (ITP) treated by different methods. METHODS: One hundred and thirty-eight newly diagnosed adult ITP patients (57 male, median age 40 years, range 18-70 years) were enrolled in this study, who were randomly separated into three regiment groups, namely prednisolone (PSL, 1.5 mg/kg for 2-4 weeks and subsequently stepwise reduction) group enrolled 49 patients, dexamethasone [(one course of high-dose dexamethasone (HDD) 40 mg/day, d1-4] 45 patients, and rituximab plus HDD (rituximab 100 mg on days 7, 14, 21, 28 and HDD) group 44 patients. Peripheral blood was taken in ITP patients of each group before treatment, 14 d and 28 d after treatment. The percentages of CD4⁺CD25(high)CD127(low) Tregs in 30 healthy controls and 138 patients were analyzed by flow cytometry. RESULTS: Overall response (OR) rates of PSL, HDD and R+HDD groups at day 28 were 69.4%, 66.7% and 79.5% respectively with no difference. After the following 12 months, sustained response (SR) was more pronounced in R+HDD group compared to the other two groups (R+HDD vs PSL: 66.7% vs 37.8%, P<0.05; R+HDD vs HDD: 66.7% vs 22.7%, P<0.05). The percentage of CD4⁺CD25(high)CD127(low) Tregs in peripheral blood of ITP patients [(1.67±0.70)%] was significantly lower than in healthy control group; After treatment, the percentages of Tregs in peripheral blood of patients both at day 14 and 28 in R+HDD group remarkably decreased compared with before treatment [(4.28±1.09)% vs (1.68±0.68)%, P<0.05; (4.44±0.63)% vs (1.68±0.68)%]. The percentages of Tregs at day 14 in both other two groups decreased notably compared with before treatment. But the Tregs levels measured at day 28 in PSL and HDD groups were similar with before treatment. CONCLUSION: The percentage of CD4⁺CD25(high)CD127(low) Tregs in peripheral blood of ITP patients was lower than healthy individual. The higher SR of patients treated by R+HDD was related to its ability to up-regulate the percentage of CD4⁺CD25(high)CD127(low) Tregs.

[Efficacy and safety of low-dose rituximab combined with different dosage of glucocorticoids for immune thrombocytopenia].

OBJECTIVE: To compare the efficacy and safety of low-dose rituximab combined with different dosage of glucocorticoids for immune thrombocytopenia (ITP). METHODS: Seventy-four patients (35 male, median age 34 years, range 18-70 years) including 60 newly-diagnosed, 6 persistent, 5 chronic and 3 refractory patients were enrolled in this study, and separated into control (36 cases) and experimental (38 cases) groups according to the dosage of glucocorticoids. Patients in both groups received dexamethasone 40 mg/day on days 1-4, followed by rituximab 100 mg on days 7, 14, 21, 28. The patients in experimental group also received decrements of prednisone 60, 30, 20, 10 mg/day on days 5-7, 8-14, 15-21, 22-28. The initial, long-term efficacy and safety were evaluated. RESULTS: Platelet counts of all patients at day 4 remarkably increased, with the median platelet count from 11(1-26) × 109/L to 84(23-132) × 109/L in control group, and 10(2-20) × 109/L to 80(22-115) × 109/L in experimental group; the platelet counts of patients at day 14 in experimental group [163(19-262) × 109/L] was higher than that of control group [98(18-238) × 109/L] (P<0.05). The overall response (OR) rates at day 28 in experimental group (84.21%) was significantly higher than that of control group (66.67%, P = 0.03). There was no significant difference of sustained response (SR) rates in two groups (63.89%vs 65.79%, 58.33%vs 60.53%, P > 0.05) at six and twelve months follow-up points. Both groups showed similar incidence of adverse events, and no patients discontinued the treatment due to side effects. CONCLUSION: Low-dose rituximab and glucocorticoids was an effective method for ITP patients, and maintenance treatment with decrements of prednisone contributed to improving earlier CR rate.

HOXA9 gene expression in acute myeloid leukemia.

Homeobox genes encode the class of transcription factors in vertebrates and are found in clusters called A, B, C, and D on four separate chromosomes. HOXA9 gene is part of the cluster A on chromosome 7 and encodes a DNA-binding transcription factor which may regulate gene expression, morphogenesis, and differentiation. The objective of this study was to determine the HOXA9 gene expression in acute myeloid leukemia (AML). For this purpose, semi-quantitative reverse transcriptase-polymerase chain reaction was used to measure HOXA9 gene expression in human erythroleukemia (HEL) cell line and bone marrow mononuclear cells from 54 AML patients and 20 healthy individuals. The data show that HOXA9 mRNA expression was negative in 20 healthy individuals but was positive in HEL cells and in 22 out of 54 (40.74%) AML patients. The complete remission rate (45.45%) of the patients who expressed the gene was significantly lower than that (71.86%) in patients who did not express the gene after chemotherapy. Therefore, it was concluded that HOXA9 gene might be involved in the pathogenesis of AML and played as a worse prognostic factor in AML.

[Expression of interleukin-22 and relative CD4(+) T cell subsets in patients with immune thrombocytopenia].

The aim of this study was to detect the expression of interleukin-22 (IL-22) and relative CD4(+) T cell subsets in untreated adult patients with immune thrombocytopenia (ITP), and to explore their roles in the pathogenesis of ITP. Fourty adult active ITP patients were enrolled in this study and 40 healthy subjects were taken as control. Plasma IL-22 level was quantified by ELISA. The percentages of Th1, Th17 and Th22 cells in peripheral blood were determined by flow cytometry. The Pearson correlation test was used to evaluate correlations between IL-22 level and Th1 cells, Th17 cells and Th22 cell percentages. The results showed that the plasma IL-22 levels in untreated ITP patients [(364.12 ± 94.22) pg/ml] were significantly higher than that in healthy controls (P < 0.001). The percentages of both Th1 [(18.92 ± 6.03)%] and Th22 [(2.28 ± 0.51)%] cells in ITP patients were elevated as compared to healthy controls (P < 0.05). Elevated plasma concentration of IL-22 positively correlated to the percentages of Th1 (r = 0.42, P = 0.022) and Th22 (r = 0.40, P = 0.030) cells in untreated ITP patients. The percentage of Th17 cells was not significantly different between untreated patients and normal controls, and there was no statistical correlation between the IL-22 level and the percentage of Th17 cells in active ITP patients. It is concluded that elevated IL-22 level correlates to Th1 and Th22 cells percentage, which may play a synergistic effect in the immunopathogenesis of ITP, while Thl7 cells may not be associated with the occurrence of active ITP.

[Propagation of prdm1 gene knockout mouse and its genotype identification].

This study was aimed to propagate and identify the prdm1 gene-knockout mice, so as to lay the foundation for studying Blimp-1 protein. Two kinds of transgenic homozygous mice with B6.prdm1(flox/flox) and B6.Lck-Cre were feed and propagated; after successful propagating, the first passage mice were obtained; after the first passage mice were copulated once again, the genotypes were obtained as follows: B6. prdm1(wild/wild). Lck-Cre, B6. prdm1(wild/wild), B6.prdm1(flox/flox). Lck-Cre, B6.prdm1(flox/wild). Lck-Cre, B6.prdm1(flox/flox), B6. prdm1(flox/wild). The genomic DNA of second passage mice was extracted, the Cre and loxp gene fragments were amplified by PCR, then the size of Cre and loxp genomic DNA were detected by agarose gel electrophoresis. The mice with B6.prdm1(flow/flox). Lek-Cre were used as conditionally prdm1-knockout mice, B6.prdm1(flox/wild). Lck-Cre mice, B6.prdm1(flox/flox) and B6 mice were used as controls. The spleen T lymphocytes and B lymphocytes were sorted by using magnetic beads, the blimp-1 target protein was identified by Western blot. The results showed that the two transgenic homozygous mice had the ability to reproduce, and the separation ratio of second passage mice generated from propagation of their offspring cach other meet Mendelian laws, and the prdm1 gene-knockout mice also could successfully obtained. It is concluded that the application of Cre-loxp system may successfully obtain plentiful prdm1 gene-knockout mice.

[Effects of immature dendritic cells genetically modified to express sTNFR I on graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) in allogeneic bone marrow transplantation mice].

OBJECTIVE: To investigate the effect of immature dendritic cells (inDC) genetically modified to express sTNFR I on acute graft-versus-host disease (aGVHD) and the graft-versus-leukemia (GVL) effect ofter allogeneic bone marrow transplantation (allo-BMT) in leukemic mice and its mechanism. METHODS: An EL4 leukemia allo-BMT model was established with the BALB/c (H-2d) donor mice (DM)and C57BL/6 (H-2b) recipient mice (RM). The RM received DM bone marrow (BM) cells at a 1:1 ratio with spleen cells intravenously via tail vein at 4 h after TBI. Fifty DM were separated randomly into five groups: (1) Group A: total body irradiation (TBI) group, (2) Group B: lymphoma cell leukemia group, (3) Group C: allo-BMT group, (4) Group D: pXZ9-DC group, (5) Group E: sTNFR I-DC group. Acute GVHD scores, incidence of leukemic cell infiltration, histopathological analysis, survival rate, and survival rate of the recipients were estimated after allo-BMT. Enzyme-linked immunosorbent assay (ELISA) method was used to detect cytokines (INF-gamma and IL-4 ) production. Flow cytometry (FCM) analysis was used to detect allogeneic chimerism. RESULTS: (1) The mice in group A and group B all died of the BM failure and lymphoma cell leukemia, respectively. The mice in group C developed typical clinical signs of a GVHD after BMT with an average survival time(AST) of (11.50 +/- 3.50) d. The signs of aGVHD were less evident in the group D and E, and their AST (21.70 +/- 5.80 and 25.80 +/- 5.20 days, respectively) were all longer than that in group C (P < 0.05). AST of group E was the longest (P < 0.05). The mice in group B all died of leukemia within 18 days after engraftment of EL4 cells. There was was no significant difference in groups C, D and E in the incidence of leukemia (P > 0.05). (2) Serum IFN-gamma level reached peak value. At + 12 d, then decreased gradually in group C, D, and E, and then reached the nadir at +18 d post-BMT, with the lowest in group E (P < 0.05), and the level was significantly lower in group D than in group C (P < 0.05). After BMT, serum IL-4 level slightly decreased in group C, but gradually elevated in group D and E and reached their peak at +12 d, and even more significantly increased in group E (P < 0.05). There was no statistical significance in the pair wise comparison among three group (P < 0.05). (3) The average proportion of H-2d positive cells in RM was 95%-100% on day 30 post-BMT, with complete donor-type implantation. CONCLUSION: Immature DC can induce immuno tolerance. Immature DC genetically modified to express sTNFR I has been shown to prevent acute GVHD in lethally irradiated mice reconstituted with allogeneic bone marrow grafts while maintaining the GVL response.

[In vitro effects of Wnt3a gene modification on mitigating damage of mouse bone marrow mesenchymal stem cells induced by Ara-C].

This study was aimed to investigate the protective effect of Wit3a gene modification on mouse bone marrow mesenchymal stem cells against the injury induced by Ara-C. The gene-modified MSC steadily expressing Wnt3a were established by adenovirus system. The acute direct damage effects of different concentrations of Ara-C on the unmodified MSC and the gene-modified MSC were assessed by using an in vitro culture system, and the corresponding controls were set. The proliferation and apoptosis of MSC exposed to Ara-C were detected by cell count kit-8 (CCK-8) and flow cytometry. The expression of BCL-2 protein related with cell apoptosis was assayed by Western blot. The results indicated that as compared with unmodified MSC, Ara-C exhibited a less inhibitory effect on the proliferation of gene-modified MSC. There was obvious difference between unmodified MSC and gene-modified MSC (p < 0.05). The proliferation of gene-modified MSC began to recover at 72 hours after removal of Ara-C. However, unmodified MSC showed sustained suppression of proliferation after withdrawal of Ara-C. In apoptosis, the apoptosis rate of gene-modified MSC induced by Ara-C was significantly lower than those of unmodified MSC (p < 0.05). In addition, the expression levels of BCL-2 protein in gene-modified MSC were up-regulated compared with unmodified MSC (p < 0.05). It is concluded that Wnt3a gene modification can significantly mitigate the damage of mouse bone marrow MSC induced by Ara-C.

[Influence of mouse genetic engineering regulatory T cells infusion on post-allogeneic bone marrow transplantation acute graft-versus-host disease in mice].

OBJECTIVE: To explore the influence of the lentiviral vector mediated mouse genetic engineering regulatory T cells (Treg) infusion on post-allogeneic bone marrow transplantation (allo-BMT) acute graft-versus-host disease (GVHD) in mice. METHODS: Lentivirus-mediated Forkhead box P3 (Foxp3) gene was transduced into BALB/c mice CD4(+)CD25(-) T cells (Treg) to construct engineered Tregs in vitro. An allo-BMT model of BALB/c to C57BL/6 mice was established. After irradiation, the recipients were injected with donor cells plus the genetic engineering Tregs. Survival time, clinical GVHD score, histopathological findings, activation of donor T cells or serum levels of inflammatory cytokines were observed after allo-BMT. RESULTS: The mean survival times for radiation alone group (Gp I), transplantation control group (Gp II), engineering Treg infusion group (Gp III) and empty vector control group (Gp IV) were (8.8 ± 0.6) d, (36.7 ± 2.5) d, (51.6 ± 4.0) d and (34.1 ± 2.3) d, respectively. The survival time was significantly longer in Gp III than in other groups (P < 0.05). Histopathological finding in several target organs (skin, liver and small intestine) confirmed the presence of severe GVHD in Gp II and Gp IV, while no histological signs of GVHD were observed in long survival recipients in Gp III, and clinical GVHD scores in Gp III were significantly lower than that in Gps II and IV. The numbers of donor T cells and the percentage of IFN-producing donor T cells in the spleen of recipients in Gp III were significant lower than those in Gps II and IV at days 3 and 4, and at day 3 after transplantation, respectively (P < 0.05). The serum levels of IFN-γ, IL-2 and TNF-α were increased at day 21 to 28 after transplantation in all groups. The peak concentrations of IFN-γ, IL-2 and TNF-α in Gp III were significantly lower than those in Gps II and IV control groups at day 21 (P < 0.05). CONCLUSION: Co-injection of genetic engineering Treg can efficiently prevent recipients from lethal GVHD after allo-BMT in mice by inhibiting the early activation and expansion of donor T cells and reducing the serum levels of inflammatory cytokines.

[Effect of Wnt3a-transduced bone marrow mesenchymal stem cells on the proliferation of T lymphocytes].

OBJECTIVE: To observe the effect of Wnt3a-transduced mouse bone marrow mesenchymal stem cells (MSC) on the proliferation of T lymphocytes. METHODS: MSC were isolated from C57BL/6 mouse bone marrow and expanded in vitro, then identified by flow cytometry and their differentiation capacity into osteocytes and adipocytes were determined. Recombinant plasmids containing Wnt3a gene, were transfected with lipofectamine into HEK293 cells by the AdEasy system. Viral particles were collected to infect MSC and adenovirus vector expressing GFP (Ad-GFP) was used as control. The expression of GFP in MSC was observed using fluorescence microscopy and the protein levels of Wnt3a and ß-catenin were determined by Western blot. Wnt3a-transduced and Ad-GFP transduced MSC were separately cocultured with spleen lymphocytes stimulated by ConA, at the ratio of 1:100, 1:50 or 1:10 respectively. The proliferation rate of T lymphocytes was estimated by Cell Cout Kit-8 (CCK-8) and the level of cytokine by ELISA. RESULTS: FCM analysis showed that the MSC were highly positive for CD90.2, CD44 and negative for CD34, CD45, they could differentiate into osteoblasts and adipocytes after induction; The titer of recombinant adenoviruses was up to 1 × 10(10) pfu/ml. After infected with the adenoviruses, MSC had the strongest GFP expression at 72 h and the efficiency of infection was 50%-60%. The expressions of Wnt3a and ß-catenin protein in the Wnt3a-transduced MSC were significantly increased. MSC could suppress the proliferation of T lymphocytes in a dose-dependent manner. When MSC cocultured with spleen lymphocytes at 1:10 ratio, T lymphocyte proliferation rate and the level of IFN-γ were (55.41 ± 1.75)% and (326.70 ± 14.41) pg/ml respectively in Ad-GFP transduced MSC group, while in Wnt3a-transduced MSC group, they were (37.27 ± 2.66)% and (218.80 ± 12.93) pg/ml respectively. There was no effect on the production of IL-2. CONCLUSION: Compared to Ad-GFP transduced MSC, Wnt3a-transduced MSC exhibit a more potent inhibitory effect on the proliferation of T lymphocytes.

[Inhibition of evi1 expression by siRNA in HEL cell line].

The aim of study was to investigate the inhibitory effect of small interfering RNA on evi1 gene expression and biological characteristics in HEL cells and its mechanism. 3 siRNA (siRNA-1, siRNA-2, siRNA-3) specific for evi1 gene were synthesized and transfected into HEL cells in vitro. Experiments were divided into test and control groups. MTT method was used to assay the inhibitory effect of siRNA on cell proliferation; semiquantitative RT-PCR was used to detect the expression of evi1 gene mRNA; the cell viability was determined by trypan blue dye test; the change of cell cycle and apoptosis of cells were analyzed by flow cytometry. The results showed that siRNA-1 had strongest effect, and inhibitory effect was most obvious at 48 hours after transfection. When the concentration of siRNA raised to 120 nmol/L, the inhibitory rate reached to the peak. The inhibitory rate of siRNA-1 on proliferation of HEL cells, relative expression level of evi1 mRNA and cell viability at 48 hours after transfection were 72.22 ± 2.80%, 27.31 ± 1.11% and 26.05 ± 2.49%, which had significant difference from other groups (p < 0.001). The siRNA resulted in arrest of cell cycle at G(0)/G(1) phase, the cell amount at S phase obviously decreased, the apoptotic rate of HEL cells obviously increased (p < 0.01). It is concluded that the siRNA specific for evi1 gene can suppress the proliferation of HEL cells, reduce the expression of evi1 mRNA, decrease the cell viability, arrest the cell cycle at G(0)/G(1) phase, suppress cell mitosis, and promote cell apoptosis.

[Establishment and identification of mouse lymphoma cell line EL4 expressing red fluorescent protein].

This study was purposed to construct a lentiviral vector encoding red fluorescent protein (DsRed) and transfect DsRed into EL4 cells for establishing mouse leukemia/lymphoma model expressing DsRed. The bicistronic SIN lentiviral transfer plasmid containing the genes encoding neo and internal ribosomal entry site-red fluorescent protein (IRES-DsRed) was constructed. Human embryonic kidney 293FT cells were co-transfected with the three plasmids by liposome method. The viral particles were collected and used to transfect EL4 cells, then the cells were selected by G418. The results showed that the plasmid pXZ208-neo-IRES-DsRed was constructed successfully, and the viral titer reached to 10(6) U/ml. EL4 cells were transfected by the viral solution efficiently. The transfected EL4 cells expressing DsRed survived in the final concentration 600 microg/ml of G418. The expression of DsRed in the transfected EL4 cells was demonstrated by fluorescence microscopy and flow cytometry. In conclusion, the EL4/DsRed cell line was established successfully.

[Influence of donor Treg cells on GVHD and GVL effects after allogeneic bone marrow transplantation in mice].

In order to explore the influence of purified donor regulatory T cells (Treg) infused after allogeneic bone marrow transplantation (allo-BMT) on GVHD and GVL effect in mice, an EL4 leukemia allo-BMT model of BALB/c-->C57BL/6 mice was established. The CD4(+)CD25(+)T cells were purified by positive selection using MACS. The recipients were injected with CD4(+)CD25(+)T cells or CD4(+)CD25(-)T cells within 4 hours respectively along with allo-BMT. Survival time, clinical GVHD score or histopathological features were observed after allo-BMT. The results showed that the mean survival time in leukemia control group was (17.9 +/- 0.7) days and all mice died of leukemia. The mean survival times in transplantation control group and CD4(+)CD25(-)T group were (23.2 +/- 1.6) and (22.3 +/- 1.9) days. Histopathological analysis in several target organs (skin, liver and small intestine) confirmed the presence of severe GVHD. The mean survival time in Treg group was (47.3 +/- 6.5) days. 70% of recipients were alive until day 60 without features of GVHD or tumor progression. Clinical GVHD scores in Treg group significantly decreased as compared to transplantation control group and CD4(+)CD25(-)T group (p < 0.05). It is concluded that allo-BMT combined with injection of donor CD4(+)CD25(+)Treg cells can efficiently prevent recipients from lethal GVHD with preserving GVL effect during allo-BMT.

[Effects of shRNA mediated BTLA silence on proliferation of mouse splenic lymphocytes].

OBJECTIVE: To investigate the proliferation of mouse splenic lymphocytes after shRNA mediated BTLA gene silence. METHODS: Three specific shRNAs and one nonspecific shRNA (scrambled) were ligated to pSilencer3.1-H1-neo plasmid and then subcloned into lentiviral vector pLB. Recombinant viral particles were harvested post-transduction to 293T cells. Mouse lymphocytes were infected with viral supernatant after 24 h incubation and continuously cultured till 4 days. Expression of eGFP was detected by fluorescence microscopy, efficiency of infection and expression of BTLA on lymphocyte cell by FCM. CCK-8 assay was used to detect the proliferation of lymphocytes. RESULTS: Lentiviral expression vectors pLB-shRNA/BTLA were successfully generated. The lentiviral particles were correctly packaged. Expression of BTLA protein in specific shRNA group was significantly decreased comparing to those in control group. O.D. value at A(450) of lymphocytes stimulated by anti-CD3 antibody showed significant difference compared with normal BTLA group (P < 0.05), while there was no difference between ConA stimulated group and control (P > 0.05). CONCLUSION: Gene-specific shRNA can knockdown the expression of BTLA. The proliferation of lymphocytes stimulated by anti-CD3 antibody after RNAi demonstrates significant enhancement as compared to the unstimulated lymphocytes, while stimulated by ConA showed no difference compared to normal lymphocytes.

[Effect of bortezomib on acute graft-versus-host disease in mice model and its mechanism].

OBJECTIVE: To investigate the effect of bortezomib on prophylaxis of acute graft-versus-host disease (aGVHD) after mouse allogeneic-bone marrow transplantation (allo-BMT) and its mechanism. METHODS: C57BL/6 (H-2(b)) mice were used as donors and BALB/c (H-2d+) mice as recipients. After allo-BMT, the BALB/c mice were divided into 3 groups, ie. group A:BMT control, group B: BMT + early infusion of bortezomib (1 mg kg(-1) d(-1), day 0-3), group C: BMT + late infusion of bortezomib (1 mg kg(-1) d(-1), day 5-7). Clinical manifestations of aGVHD, pathohistological changes, survival rate and levels of recipients H-2(b) cells detected by flow cytometry in the recipient mice were observed. Monodirectional mixed lymphocyte culture (MLC) system was established ex vivo and different concentrations of bortezomib (0, 2, 4, 8 nmol/L) were added to the system. The viability of the cells was detected by CCK-8 assay and cells apoptosis by flow cytometry. The concentrations of IL-2, IFN-gamma, TNF-alpha in the supernatant were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: The mice in group A developed typical aGVHD and all died of aGVHD within 3 weeks after transplantation, with a median survival time of (16.1 +/- 2.5) d. The symptoms of aGVHD was milder in group B than in group A, and the median survival time was significantly longer. The 60-day survival rate in group B was 70%, being significantly higher than that in other two groups(P<0.05). The mean value of donor-derived cell (H-2(b) cells) in group B was (98.1 +/- 1.1)% at 60 days. The symptoms of aGVHD was significantly severer in group C than in group A, and the median survival time was shorter. Bortezomib inhibited the cells viability in MLC system in a dose-dependent manner. After treated with 8 nmol/L bortezomib for 24 h, the inhibition ratio of cells viability was (41.4 +/- 6.0)%. The cell apoptosis rate increased gradually with bortezomib treatment for 12 h, 24 h and 36 h. After treated with 8 nmol/L bortezomib for 36 h, the apoptosis rate was (62.8 +/- 7.0)%. After treated for 24 h, the levels of IL-2, IFN-gamma and TNF-alpha in the supernatant were decreased. CONCLUSIONS: Bortezomib administered immediately after allogeneic BMT can prevent aGVHD, improve the survival rate and have no influence of engraftment in the recipient mice. Delayed administration of bortezomib results in acceleration of aGVHD-induced mortality. Its mechanism maybe inhibition of the lymphocyte viability, increase of the cells apoptosis rate, and inhibition of secretion of IL-2, IFN-gamma, and TNF-alpha.

[Development of genetic engineering regulatory T cells mediated by the self-inactivating lentiviral vectors].

OBJECTIVE: To prepare the genetic engineering regulatory T cells (Treg) via the self-inactivating (SIN) lentiviral vectors carrying Foxp3 gene, and assay the phenotype and abilities of its proliferation and immunosuppression. METHODS: The bicistronic SIN lentiviral transfer plasmid containing Foxp3 gene and internal ribosomal entry site-green fluorescent protein gene (IRES-GFP) was constructed. Human embryonic kidney 293T cells were co-transfected using liposome by lentiviral packing system, which included the packaging plasmid Delta NRF, the transfer plasmid and the envelope plasmid VSVG. The efficiency of gene transduction and the expressions of Foxp3, CD25, GITR, CTLA-4 of CD4(+)CD25(-) T cells, which were isolated by magnetic beads from the spleen, and then co-cultured with 293T cells, were detected by flow cytometry (FCM). The proliferative and suppressive capacities of transduced T cells were estimated by Cell Count Kit-8 (CCK-8) and the cytokine production was performed by ELISA. RESULTS: The lentiviral transfer plasmid pXZ208-Foxp3-IRES-GFP was successfully constructed, the virus titers were above 10(6) IU/ml in the supernatant. pXZ208-IRES-GFP was used as control group. After cocultured, the CD4(+)CD25(-) T cells expressed significantly higher Foxp3, CD25, GITR and CTLA-4 in experimental group than in control group. Upon stimulation with anti-CD3 epsilon and APCs, the proliferative capacity of Foxp3-transduced T cells and the production of IL-2, IL-4, IL-10, IFN-gamma were significantly lower than those in control group (P < 0.01); Foxp3-transduced T cells also significantly inhibited the proliferation of CD4(+)CD25(-) T cells. CONCLUSIONS: The genetic engineering Treg mediated by SIN lentiviral vectors are successfully constructed and their phenotype and function are similar to natural CD4(+)CD25(+) Treg.