Arginine methyltransferases PRMT2 and PRMT3 are essential for biosynthesis of plant-polysaccharide-degrading enzymes in Penicillium oxalicum.

Many filamentous fungi produce plant-polysaccharide-degrading enzymes (PPDE); however, the regulatory mechanism of this process is poorly understood. A Gal4-like transcription factor, CxrA, is essential for mycelial growth and PPDE production in Penicillium oxalicum. Its N-terminal region, CxrAΔ207-733 is required for the regulatory functions of whole CxrA, and contains a DNA-binding domain (CxrAΔ1-16&Δ59-733) and a methylated arginine (R) 94. Methylation of R94 is mediated by an arginine N-methyltransferase, PRMT2 and appears to induce dimerization of CxrAΔ1-60. Overexpression of prmt2 in P. oxalicum increases PPDE production by 41.4-95.1% during growth on Avicel, compared with the background strain Δku70;hphR+. Another arginine N-methyltransferase, PRMT3, appears to assist entry of CxrA into the nucleus, and interacts with CxrAΔ1-60 in vitro under Avicel induction. Deletion of prmt3 resulted in 67.0-149.7% enhanced PPDE production by P. oxalicum. These findings provide novel insights into the regulatory mechanism of fungal PPDE production.

Regulatory function of the novel transcription factor CxrC in Penicillium oxalicum.

Numerous transcription factors (TFs) in ascomycete fungi play crucial roles in cellular processes; however, how most of them function is poorly understood. Here, we identified and characterized a novel TF, CxrC (POX01387), acting downstream of the key TF CxrA, which is essential for plant-biomass-degrading-enzyme (PBDE) production in Penicillium oxalicum. Deletion of cxrC in P. oxalicum significantly affected the production of PBDEs, as well as mycelial growth and conidiospore production. CxrA directly repressed the expression of cxrC after about 12 hr following switch to Avicel culture. CxrC bound the promoters of major PBDE genes and genes involved in conidiospore development. CxrC was found to bind the TSSGTYR core sequence (S: C and G; Y: T and C; R: G and A) of the important cellulase genes cbh1 and eg1. Both N- and C-terminal peptides of CxrC and the CxrC phosphorylation were found to mediate its homodimerization. The conserved motif LPSVRSLLTP (65-74) in CxrC was found to be required for regulating cellulase production. This study reveals novel mechanisms of TF-mediated regulation of the expression of PBDE genes and genes involved in cellular processes in an ascomycete fungus.

[Effects of hypoxia on the proliferation of human bone marrow mesenchymal stem cells].

OBJECTIVE: To study the effect of hypoxia on the proliferation of human bone marrow mesenchymal stem cells (hBMSCs). METHODS: The method of density gradient centrifugation was employed to isolate and culture hBMSCs. And flow cytometry (FCM) was employed to detect the cell surface marker. After establishing the experimental model of CoCl2-chemical hypoxia, MTT method and flow cytometry were applied to evaluate the proliferation and the proliferation index of hBMSCs at different time points with various CoCl2 concentrations. RESULTS: The proliferations of hBMSCs was inhibited within the first 12 hours under chemical hypoxia condition. Compared with the normal group, the hBMSCs of each CoCl2 group were remarkably proliferated 1, 2, 4 days after chemical hypoxia with CoCl2, but 300 µmol/L CoCl2 group showed no significant difference (P > 0.05). 100 µmol/L CoCl2 group (0.139 ± 0.003, 0.178 ± 0.005, 0.224 ± 0.005) and 150 µmol/L CoCl2 group (0.202 ± 0.020, 0.224 ± 0.019, 0.263 ± 0.004) proliferation was significantly higher than that of the control group (0.134 ± 0.005, 0.167 ± 0.004, 0.206 ± 0.005). Compared with the normal group, the hBMSCs were remarkably proliferated 24 hours after chemical hypoxia with CoCl2 concentration of 150 µmol/L (all P < 0.05). At Day 6, the 100, 150 µmol/L CoCl2 group (0.258 ± 0.020, 0.264 ± 0.008) cells was still higher than that of normal group (0.248 ± 0.004), but the advantage gradually diminished (P < 0.05). At Day 7, the proliferative effects of hypoxia disappeared. CONCLUSION: CoCl2-induced chemical hypoxia may promote the proliferation of hBMSCs.

[Autologous bone marrow-derived mesenchymal stem cells and peripheral blood stem cells cotransplantation in treatment of hematological malignant diseases].

OBJECTIVE: To explore the feasibility and safety of cotransplantation of autologous bone marrow-derived mesenchymal stem cells (MSCs) and peripheral blood stem cells in hematological malignant diseases and to observe its effect on hematopoietic reconstruction after cotransplantation. METHODS: Adult human MSCs were isolated from the healthy bone marrow of the patient himself with Percoll (1.073 g/ml) and cultured in Dulbecco's modified Eagle's medium with low glucose containing 10% AB type human serum. After conditioning regimen of high-dose chemotherapy and radiotherapy, cotransplantation of autologous bone marrow-derived MSCs and peripheral blood stem cells was done in five patients with hematological malignant diseases. RESULTS: The process of the infusion was safe and there were no adverse reactions or other toxicities related to the infusion of MSCs. The median time to achieve neutrophil counts greater than 0.5x10(9)/L was 9.4 days (ranging from 8 to 11 days) after cotransplantation and platelet counts greater than 20x10(9)/L 12.2 days (ranging from 10 to 14 days). CONCLUSION: Cotransplantation of autologous bone marrow-derived MSCs and peripheral blood stem cells in hematological malignant diseases is feasible and safe. The rapid hematopoietic reconstruction after cotransplantation shows that MSCs have an effect on hematopoiesis, but the mechanism is still to be investigated.

[Relationship between Gene Polymorphism of HLA-A(*)/-B(*)-DRB1(*) and Aplastic Anemia in Chinese Han Population of Northwestern Plateau].

OBJECTIVE: To investigate the correlation between the HLA genes and pathogenesis of aplastic anemia (AA), so as to find the susceptible AA genes. METHODS: Polymerase chain reaction with specific sequence primers (PCR-SSP) method was used to detect the HLA typing of 50 AA patients and 183 normal healthy individuals as controls in Chinese Han population of northwestern plateau. RESULTS: The frequency of HLA-A* 0201 (45.0%), B* 1501 (11.0%), B* 5501 (9.0%) and DRB1* 0901 (19.0%) gene frequences in AA patients were significantly higher than those in controls (Odds Ratio: OR=1.657, 2.138, 2.314 and 1.932, x2=4.882, 3.876, 3.863 and 4.473 (P<0.05). In contrast, A* 0301 gene frequency (4.0%) in AA was significantly lower than that in controls, OR=0.349, x2=4.154 (P<0.05). The male HLA-A* 0201 gene frequency was lower than that in female (38.2% vs 59.4%), and the difference was statistically significant (P<0.05). Concludsion: The HLA-A* 0201, B* 1501, B* 5501 and DRB1* 0901 genes may be considered as the risk markers while A* 0301 gene as a protective marker of AA, the HLA-A* 0201 also shows the sex differences.

[Application of Chimeric Antigen Receptor-Modified CAR-T/NK Cells to Treatment of Multiple Myeloma].

Chimeric antigen receptor(CAR) is a synthesized transmembrane protein, which redirects the modified cells through specific or associated antigen on tumor cells. CAR-modified T/NK cells, especially CAR-T cells, are a new tool of rapidly developing of adoptive immunotherapy of tumor in recent years, they give T/NK cells the targeting cytotoxic activity and can overcome the tumor immunosuppressive microenvironment and break the state of the host immune tolerance. CAR combines the single-chain antibody to tumor-associated antigen with T/NK cells' activated motifs, giving T/NK cells' tumor targeting activity, so enhancing their cytotoxic activity and lasting the vitality by gene transduction. In this article the CAR development, comparison of CAR-T and CAR-NK cells, surface markers on MM cells and use of CAR in MM, and CAR perspectives are summarized.

[Apoptosis and regulation of expressions of apoptosis-related gene Bcl-2 and p53 induced by selenium dioxide in three leukemia cell lines].

OBJECTIVE: To investigate the mechanisms underlying the effect of selenium dioxide (SeO(2)) on the proliferation, apoptosis, and apoptosis-related gene expressions of Bcl-2 and p53 in 3 leukemia cell lines NB4, K562 and HL-60. METHODS: The three leukemia cell lines were treated with 3, 10 and 30 mmol/L SeO(2) and apoptosis detected by flow cytometry and analysis of p53 and Bcl-2 expressions. RESULTS: SeO(2) at 10 and 30 mmol/L could inhibit the proliferation of three leukemia cell lines. SeO(2) treatment at 30 mmol/L for 48 h induced an apoptosis rate of 54.0 %, 46.5 %, 49.6 % in NB4, K562, and HL-60 cells respectively, and down-regulated Bcl-2 expression in NB4 and K562 but not in HL-60 cells. CONCLUSION: SeO(2) can induce apoptosis in NB4, K562 and HL-60 leukemia cells, involving the down-regulation of Bcl-2 and up-regulation of p53.

[Effects of interferon-γ on expression of adhesion molecules in human umbilical cord mesenchymal stromal cells].

This study was purposed to investigate the effects of interferon (IFN)-γ on expression of adhesion molecules in mesenchymal stromal cells derived from human umbilical cord tissue (UC-MSC). The UC-MSC were isolated from human umbilical cord by tissue culture. The expressions of specific markers on UC-MSC were detected by flow cytometry in the physiological condition. The adipogenic and osteogenic induction of UC-MSC was detected by alizarin and Oil red O staining. UC-MSC were exposed to IFN-γ (100, 1 000, 10 000 U/ml) for 24 h, the expressions of CD54, CD58, CD44, CD49d, CD62p, CD62L, CD102 and CD106 on cell surface were detected using flow cytometry. The results showed that in physiological condition, UC-MSC extremely low expressed CD102, CD106, CD62P, CD62L, while the expression of CD54 was relatively high (41.58 ± 0.83)%. When stimulated by IFN-γ, the expression of CD102, CD106, CD62P, CD62L increased slightly, but still low (< 5%), while CD54 and CD58 upregulated concentration-dependently up to (59.66 ± 1.36)% and (43.96 ± 0.62)% respectively. The expression of CD49d upregulated to (51.33 ± 0.74)% when UC-MSC exposed to IFN-γ 100 U/ml. CD44 increased to (73.22 ± 1.93)% when UC-MSC exposed to IFN-γ 1 000 U/ml. It is concluded that IFN-γ can elevate significantly the expression of CD54, CD49d, CD44 and CD58, but has no significant effect on CD102, CD106, CD62P and CD62L expression on the surface of UC-MSC.

[Expression characteristics of SDF-1 receptor CXCR4 in mesenchymal stem cells derived from human umbilical cord tissue].

The purpose of this study was to explore the expression characteristics of SDF-1 receptor, CXCR4, in mesenchymal stem cells (MSC) of different passages derived from human umbilical cord (hucMSC). The hucMSC were isolated from Wharton's jelly tissue of human umbilical cord by tissue culture. The expressions of specific marker in hucMSC were detected by flow cytometry. The adipogenic and osteogenic induction of hucMSC were detected by alizarin bordeaux and Oil red O staining. The expressions of CXCR4 protein in hucMSC of 2nd-5th passages were detected by flow cytometry, and cxcr4 mRNA levels in hucMSC of 2nd-5th passages were evaluated by real-time quantitative PCR. The results showed that the expression of CD44, CD13, CD71 were positive while CD38, CD117, HLA-DR were negative. After induced by osteogenic and adipogenic inductors, the lipid droplets and calcium nodals appeared in hucMSC, hucMSC stained with oil red O and alizarin red were shown to be positive. The cxcr4 was found in hucMSC of 2nd-5th passages, and their expressions were (89.82 ± 0.62)%, (86.87 ± 1.32)%, (80.50 ± 4.46)%, (70.10 ± 0.68)% respectively. The cxcr4 mRNA was found in hucMSC of 2nd-5th passages, and expression of cxcr4 of 3rd-5th passages were 0.5585 ± 00875, 0.6205 ± 0.1377, 0.4634 ± 0.0447 times of expression of 2nd passage respectively. It is concluded that the cxcr4 mRNA expresses in hucMSC of 2nd-5th passages, and declines when the number of passages increases. Compared with 2nd passage, cxcr4 mRNA levels in hucMSC of 3rd-5th passages decline, but the expression level of cxcr4 mRNA between hucMSC of 3rd-5th passages is stable.

[Effects of peptidoglycan on proliferation and cell cycle of human bone marrow-derived mesenchymal stem cells].

This study was aimed to explore the effects of peptidoglycan (PGN) on proliferation and cell cycle of human bone marrow mesenchymal stem cells (MSCs). MSCs were isolated from human bone marrow by density gradient centrifugation. The purity of MSCs with the spindle fibroblastic morphology was identified by microphotography and the phenotypes were detected by flow cytometry (FCM). MSCs incubated with different doses of PGN (1, 10, 20 µg/ml) were used as test groups, and those incubated without PGN were regarded as control group. The isolated and cultured MSCs were inoculated into 96-well plates according to a certain concentration. Cell cycle was measured by flow cytometry after incubated with PGN for 72 hours. The results showed that the cell proliferation index was significantly increased in dose and time dependent manners after MSCs was incubated with PGN. Its effects on the proliferation of MSCs were highest in 10 µg/ml group. Compared with the control group, PGN could significantly decrease proportion of MSCs in G0/G1 phase and increase them in S and G2/M phases (p < 0.05). It is concluded that PGN can promote more MSCs to enter the DNA synthesis phase and proliferate many much MSCs in dose and time dependent manners.

Allogeneic peripheral blood hematopoietic stem cell transplantation in malignant hematopoietic diseases.

To evaluate the use of allogeneic peripheral blood stem cell transplantation (allo-PBSCT) for treatment of acute and chronic leukemia, from March 1997 to January 2003, 21 adult patients with malignant hematopoietic diseases underwent allo-PBSCT from HLA-identical siblings (19 patients) and haplo-identical mother (one) and one B point site mismatched sibling (one). All donors were mobilized with G-CSF for 4 days and peripheral blood stem cells were collected by CS-3000 separator. The conditioning regimen included the high dose combination chemotherapy and TBI. Cyclosporine-A (CsA) plus a short course of MTX was used for GVHD prophylaxis in all patients. The results showed that after trans plantation, median time for the recovery of granuocyte > or = 0.5 x 10(9)/L and platelets > or = 20 x 10(9)/L were 12 (10 - 20) and 15 (11 - 35) days, respectively. Acute GVHD was observed in 8/17 patients (47%), of which one transplanted from HLA-haploidentical mother. Chronic GVHD occurred in 12/17 patients (70%). All of four female survivals did not show acute and chronic GVHD. Day 100 transplantation-related mortality was 14% (3/21). Relapse occurred in two patients (9.5%) who underwent allo-PBSCT in stage of non-remission at one and six months. After follow-up of 40 (15 - 70) months, 11 patients (52.4%) are still disease-free survival. These results suggested that peripheral blood stem cells produce a faster hematopoietic recovery and a lower relapse of leukemia. The rate of aGVHD is not increased when using the peripheral blood as source of stem cells; however, cGVHD continues to be a significant problem. Donors tolerated the procurement procedure without complications.