The mitogen-activated protein kinase kinase kinase kinase GCKR positively regulates canonical and noncanonical Wnt signaling in B lymphocytes

Wnt ligands bind receptors of the Frizzled (Fz) family to control cell fate, proliferation, and polarity. Canonical Wnt/Fz signaling stabilizes beta-catenin by inactivating GSK3beta, leading to the translocation of beta-catenin to the nucleus and the activation of Wnt target genes. Noncanonical Wnt/Fz signaling activates RhoA and Rac, and the latter triggers the activation of c-Jun N-terminal kinase (JNK). Here, we show that exposure of B-lymphocytes to Wnt3a-conditioned media activates JNK and raises cytosolic beta-catenin levels. Both the Rac guanine nucleotide exchange factor Asef and the mitogen-activated protein kinase kinase kinase kinase germinal center kinase-related enzyme (GCKR) are required for Wnt-mediated JNK activation in B cells. In addition, we show that GCKR positively affects the beta-catenin pathway in B cells. Reduction of GCKR expression inhibits Wnt3a-induced phosphorylation of GSK3beta at serine 9 and decreases the accumulation of cytosolic beta-catenin. Furthermore, Wnt signaling induces an interaction between GCKR and GSK3beta. Our findings demonstrate that GCKR facilitates both canonical and noncanonical Wnt signaling in B lymphocytes.     

Two structural genes on different chromosomes are required for encoding the major subunit of human red cell glucose-6-phosphate dehydrogenase

Structural analysis revealed the existence of two types of subunits in human red cell glucose-6-phosphate dehydrogenase. The two subunits have the same COOH region consisting of 479 amino acid residues, but their NH2-terminal regions are different in size and sequence. The minor subunit can be fully encoded by the X-linked G6PD cDNA, but the NH2-terminal region of the major subunit cannot. The cDNA and the gene for the NH2-terminal region of the major subunit were cloned and characterized. Southern blot hybridization indicated that the gene for the NH2-terminal region is on chromosome 6, not on the X chromosome. Northern blot hybridization demonstrated an existence of two separate mRNA components, one for the COOH-terminal region and the other for the NH2-terminal region. Two separate structural genes, the X-linked and chromosome 6-linked genes, must be coresponsible for encoding the single chain subunit. Either cross-translation of two mRNAs, or transpeptidation, or some other mechanism must be involved in the synthesis of human red cell G6PD.     

Aquaporin-2 expression in human endometrium correlates with serum ovarian steroid hormones

The aim of the present study was to examine the expression of aquaporin-2 (AQP2), a member of the water channel family aquaporins (AQPs), in human uterine endometrium and its modulation of ovarian steroid hormone at the proliferative and secretory phases. Western blot, immunohistochemistry, and RT-PCR were employed in the present study. Western blot revealed a 29-kDa band that represented AQP2 in human endometrium. The expression of AQP2 in endometrium was confirmed by RT-PCR and immunohistochemical results. The immunohistochemical analysis demonstrated that AQP2 was prominent in luminal and glandular epithelial cells of endometrium. The levels of endometrial AQP2 expression changed during the menstrual cycle and were higher in the secretory endometrium than in the proliferative endometrium. A significantly high level of AQP2 was detected at the mid-secretory phase. There was a positive correlation between the levels of the endometrial AQP2 expression and the concentrations of the serum 17beta-estradiol (E2) or/and progesterone (P4). These data for the first time corroborate that AQP2 is expressed in human endometrium and that the expression of AQP2 in human endometrium might be regulated by E2 or/and P4. The changed expression of AQP2 at different phases of the menstrual cycle may be essential to reproductive physiology in human. The high level of endometrial AQP2 expression was observed at the mid-secretory phase, the time of embryo implantation, suggesting that AQP2 might play physiological roles in the uterine receptivity.     

Thymosin beta4 and AcSDKP inhibit the proliferation of HL-60 cells and induce their differentiation and apoptosis

Our previous works have shown that bone marrow stromal cells secrete thymosin beta4 (Tbeta4) and AcSDKP. Tbeta4 and AcSDKP are existed in the conditioned medium of bone marrow endothelial cells. They exerted inhibitory effects on hematopoietic cells and then had protective effect on the early hematopoietic cells, which were cultured in the presence of hematopoietic stimulators. Thymosin beta4 consists of 43 peptides with a molecular weight of 4963. It contains at its N-terminal end the sequence of the acetylated tetrapeptide Ac-N-Ser-Asp-Lys-Pro (AcSDKP). This study was performed to evaluate the effect of Tbeta4 and AcSDKP on the growth of HL-60 cells. It was showed that Tbeta4 (10(-11)-10(-7)mol/L) and AcSDKP (10(-11)-10(-7)mol/L) had the dose-dependent inhibitory effect on the proliferation of HL-60 cells. Based on cell morphology and NBT reduction, Tbeta4 and AcSDKP induced differentiation of HL-60 cells. Morphologic and DNA fragment analysis proved that Tbeta4 and AcSDKP induced apoptosis of HL-60 cells. In order to analyze the mechanism of the effects of Tbeta4 and AcSDKP, intracellular free Ca(2+) concentration ([Ca(2+)](i)) of HL-60 leukemic cells was tested and Atlas cDNA Expression Array was performed. The results showed that Tbeta4 and AcSDKP could increased [Ca(2+)](i) by stimulating the release of Ca(2+) from intracellular Ca(2+) pool. Moreover, AcSDKP could also elicit a potent extracelluar calcium influx in HL-60 cells. Tbeta4 could also change apoptotic-related gene expression in leukemic cells, and resulted in the inhibition of proliferation and induction of differentiation and apoptosis of leukemic cells.     

FADD self-association is required for stable interaction with an activated death receptor

Receptor-mediated programmed cell death proceeds through an activated receptor to which the death adaptor FADD and the initiator procaspases 8 and/or 10 are recruited following receptor stimulation. The adaptor FADD is responsible for both receptor binding and recruitment of the procaspases into the death-inducing signaling complex. Biochemical dissection of the FADD death effector domain and functional replacement with a coiled-coil motif demonstrates that there is an obligatory FADD self-association via the DED during assembly of the death-inducing signaling complex. Using engineered oligomerization motifs with defined stoichiometries, the requirement for FADD self-association through the DED can be separated from the caspase-recruitment function of the domain. Disruption of FADD self-association precludes formation of a competent signaling complex. On this basis, we propose an alternative architecture for the FADD signaling complex in which FADD acts as a molecular bridge to stitch together an array of activated death receptors.     

Daily temperature profiles in and around Western Kenyan larval habitats of Anopheles gambiae as related to egg mortality

Background

Erythrocyte invasion by Plasmodium falciparum parasites represents a key mechanism during malaria pathogenesis. Erythrocyte binding antigen-181 (EBA-181) is an important invasion protein, which mediates a unique host cell entry pathway. A novel interaction between EBA-181 and human erythrocyte membrane protein 4.1 (4.1R) was recently demonstrated using phage display technology. In the current study, recombinant proteins were utilized to define and characterize the precise molecular interaction between the two proteins.

Methods

4.1R structural domains (30, 16, 10 and 22 kDa domain) and the 4.1R binding region in EBA-181 were synthesized in specific Escherichia coli strains as recombinant proteins and purified using magnetic bead technology. Recombinant proteins were subsequently used in blot-overlay and histidine pull-down assays to determine the binding domain in 4.1R.

Results

Blot overlay and histidine pull-down experiments revealed specific interaction between the 10 kDa domain of 4.1R and EBA-181. Binding was concentration dependent as well as saturable and was abolished by heat denaturation of 4.1R.

Conclusion

The interaction of EBA-181 with the highly conserved 10 kDa domain of 4.1R provides new insight into the molecular mechanisms utilized by P. falciparum during erythrocyte entry. The results highlight the potential multifunctional role of malaria invasion proteins, which may contribute to the success of the pathogenic stage of the parasite's life cycle.     

纤维素多孔微载体的制备及其用于动物细胞培养

将纤维素铜氨溶液喷洒至-40℃的硅油：正己烷=1：4的冷冻液中形成含冰晶的微球,用-30℃、40%的H₂SO₄再生纤维素,并用EDAE盐酸盐修饰其表面,制成适合动物细胞培养的纤维素多孔微载体。利用该微载体培养能分泌尿激酶原(Pro-UK)的重组CHO细胞,在100mL搅拌瓶中换液培养25d,细胞最高密度为6.3×10⁶/mL,尿激酶原最高活性为2325IU/mL,共获28.7mg产品。之后转入1000mL搅拌瓶中培养,可观察到细胞可从种子微载体中自动转移到新微载体中生长繁殖直至所有微载体中都长有细胞。在25d二级培养中,细胞最高密度为7.3×10⁶/mL,尿激酶原最高活性为3108IU/mL,共获含353mg尿激酶原的上清13.7L。在培养后期换用无血清培养基培养,细胞生长及蛋白表达水平正常。     

ToRCH系列酶标诊断试剂的研制

报道了用辣根过氧化物酶标记的抗人ＩｇＧ和抗人ＩｇＭ（ｕ链）单克隆抗体作第二抗体,用自己培养、纯化的弓形体（Ｔｏ）、风疹病毒（ＲｕＶ）、巨细胞病毒（ＣＭＶ）和单纯疱疹病毒（ＨＳＶ１２）的虫体和病毒抗原包被酶标板,研制出检测ＴｏＲＣＨ系列的特异性ＩｇＧ和ＩｇＭ的间接ＥＬＩＳＡ试剂。质量检定结果表明,该试剂特异性强、本底低,能有效消除ＲＦ因子等干扰因素的影响;灵敏度达１∶１６０～６４０;精密性好,变异系数（Ｃ．Ｖ）在１．４％～９．０％;试剂稳定,３７℃存放４ｄ,各项指标的变化率不超过１５％。     

Aldose reductase is a potent regulator of TGF-β1 induced expression of fibronectin in human mesangial cells

Glomerulosclerosis is considered to be the final pathway leading to the progressive loss of renal function in several kidney diseases, transforming growth factor β1 (TGF-β1) plays a critical role in glomerulosclerosis. However, the mechanisms of TGF-β1 stimulating glomerulosclerosis remain poorly understood. Here we report that TGF-β1-induced expression of fibronectin (FN) depends on the activity of aldose reductase (AR) in human mesangial cells (HMCs).The results show that TGF-β1 increased the expression of FN, which attenuated by pharmacological inhibition of AR or knockdown of the enzyme by small interfering RNA (siRNA). MAPKs (ERK, JNK and p38) signalling pathways were activated in HMCs after stimulated by TGF-β1, inhibition of AR blunted the activation ERK, p38 and JNK signalling pathways. These changes were associated with decreased TGF-β1-induced expression of FN. These results indicate that AR is a potent regulator of TGF-β1 induced expression of FN in human mesangial cells: it suggests that inhibition of this enzyme may be useful to prevented extracellular matrix (ECM) deposition in glomerulosclerosis.     

Population genetic analysis of 6 Y-STR loci in Chinese northwestern Qinchuan yellow cattle breed

Six Y-STR loci (UMN0929, UMN0108, UMN0920, INRA124, UMN2404 and UMN0103) were analyzed using 576 healthy and unrelated males and 10 females of the Qinchuan cattle population in Chinese Shaanxi Province. Allele frequency, gene diversity, the polymorphic information content, and the number of effective gene were calculated. All loci were in accordance with the Hardy–Weinberg equilibrium (P > 0.05). The population data were compared with published data of other cattle breeds, suggesting that Qinchuan cattle were originated primarily from Bos Taurus. Results are valuable for individual identification, paternity testing, and origin analysis of Qinchuan cattle breed.