Nrf2 protects human lens epithelial cells against H2O2-induced oxidative and ER stress: The ATF4 may be involved.

Our previous study has shown heme oxygenase-1 (HO-1) protects human lens epithelial cells (LECs) against H2O2-induced oxidative stress and apoptosis. Nrf2, the major regulator of HO-1, is triggered during the mutual induction of oxidative stress and ER stress. In response to ER stress, unfolded protein response (UPR) serves as a program of transcriptional and translational regulation mechanism with PERK involved. Both Nrf2 and ATF4 are activated as the downstream effect of PERK signaling coordinating the convergence of dual stresses. However, the ways in which Nrf2 interacting with ATF4 regulates deteriorated redox state have not yet been fully explored. Here, the transfected LECs with Nrf2 overexpression illustrated enhanced resistance in morphology and viability upon H2O2 treatment condition. Intracellular ROS accumulation arouses ER stress, initiating PERK dependent UPR and inducing the downstream signal Nrf2 and ATF4 auto-phosphorylation. Further, converging at target promoters, ATF4 facilitates Nrf2 with the expression of ARE-dependent phase II antioxidant and detoxification enzymes. According to either Nrf2 or ATF4 gene modification, our data suggests a novel interaction between Nrf2 and ATF4 under oxidative and ER stress, thus drives specific enzymatic and non-enzymatic reactions of antioxidant mechanisms maintaining redox homeostasis. Therapies that restoring Nrf2 or ATF4 expression might help to postpone LECs aging and age-related cataract formation.

[Effects of interleukin 21 on anti-leukemia activity of cytotoxic T lymphocytes induced by dendritic cells].

This study was aimed to explore the effects of interleukin 21 (IL-21) on the anti-leukemia activity of cytotoxic T lymphocytes (CTL) induced by dendritic cells (DCs) in vitro. The peripheral mononuclear cells from leukemia patients in complete remission were cultured with the specific cytokines to induce the production of DCs. The DCs loaded with RNA from autologous leukemic cells as antigen, and co-cultured with autologous T lymphocytes to get leukemia specific CTL. The cytotoxic activity of CTL against autologous leukemic cells was measured by LDH release method. The concentration of IFN-gamma and TNF-alpha in the culture supernatant was measured by enzyme immunoassay. The effects of IL-21 on the mature DCs were also studied by the measurement of the phenotype of DC and the allogenic mixed lymphocytic reactions induced by DCs. Experiments were divided into 2 groups: test group in which IL-21 (200 ng/ml) was added in coculture of DC/CTL and control group in which no IL-21 (200 ng/ml) was added. The results showed that when cultured with IL-21, the quantity of CTL increased from (56.73 +/- 10.21)% (control group) to (73.43 +/- 18.01)% (p < 0.01); The concentration of IFN-gamma and TNF-alpha in the culture supernatant increased from (154.91 +/- 67.20) ng/L (control group) to (310.62 +/- 141.15) ng/L (p < 0.01) and from (8.77 +/- 5.09) microg/L (control group) to (15.25 +/- 6.56) microg/L (p < 0.01) respectively. At the effector: target ratio of 20:1, the cytotoxic activity against autologous leukemic cells by CTL increased from (50.22 +/- 5.07)% (control group) to (75.38 +/- 9.47)% (p < 0.01). IL-21 had neither effect on the phenotype (CD1a, CD83, CD86, CD80 and HLA-DR) of mature DCs nor the allogeneic mixed lymphocytic reactions induced by DCs. It is concluded that IL-21 can strengthen the proliferation of CTL, and improve the production of IFN-gamma and TNF-alpha, thus enhance the anti-leukemia activity of CTL. Nevertheless, there is no effect of IL-21 on the function of mature DCs. These data indicate that IL-21 has a potential clinical value in the enhancement of anti-leukemia immunotherapy.

[Wilms' tumor-1 gene expression in myelodysplastic syndrome and its changes in the process of myelodysplastic syndrome transforming into acute leukemia].

OBJECTIVE: To observe expression of Wilms' tumor-1 (WT1) gene in the different subtypes of myelodysplastic syndrome (MDS), and to explore the regularity of expression of WT1 gene in the process of MDS transforming into acute leukemia (AL). METHODS: The method of reverse transcriptase-polymerase chain reaction (RT-PCR) was used, the levels of WT1 gene's presentation in different types of montagers of MDS were analyzed, and the relationship between the level and the clinical characteristic was analyzed. At the same time, the expression of WT1 gene in AL patients, post-MDS-AL patients and normal controls were examined. RESULTS: The positive rate of WT1 gene expression in 49 patients with MDS was 22.4 percent (11/49), refractory anemia (RA) was 0(0/13), RA with excess of blast (RAEB) was 25.0 percent (6/24); RAEB in transformation (RAEB-t) was 41.7 percent (5/12). The positive rates of WT1 expression were gradually increased in three types of MDS (P<0.05 and P<0.01). The positive rates of WT1 expression were higher in AL and post-MDS-AL patients (48.5 percent, 32/66 and 50.0 percent, 4/8) than that in MDS patients (P<0.01). There was no expression of WT1 gene in normal control. CONCLUSION: There is a relatively high expression rate of WT1 gene in RAEB, RAEB-t of MDS, but relatively low expression rate in RA. The method of RT-PCR, is high sensitiveness and specificity, can trustful be used in the progression of monitoring MDS' progression and its transformation into AL.