Humanin delays apoptosis in K562 cells by downregulation of P38 MAP kinase

Humanin (HN) is a newly identified neuroprotective peptide. In this study, we investigated its antiapoptotic effect and the potential mechanisms in K562 cells. Upon serum deprivation, expression of HN in K562 cells decreased and its intracellular distribution changed from cytoplasm to cell membrane. In HN stably transfected K562 cells, apoptosis was delayed compared with control vector transfected cells as measured by flow cytometry. Furthermore, analysis of different mitogen-activated protein (MAP) kinases activity revealed that extracellular signal-regulated kinase (ERK) pathway was inhibited while p38 signaling was activated following serum deprivation in K562 cells. And in HN transfected K562 cells, ERK downregulation was not affected, but p38 activation was suppressed, which may responsible for the delayed apoptosis in these cells. Activation of the ERK signaling pathway by phorbol myristate 13-acetate (PMA) and sorbitol protected K562 cells from serum deprivation induced apoptosis. Additionally, overexpression of HN reduced megakaryocytic differentiation of K562 cells. The present data outline the role of ERK and p38 MAP kinases in serum deprivation induced apoptosis in K562 cells and figure out p38 signaling pathway as molecular target for HN delaying apoptosis in K562 cells.

SU proteins from virulent and avirulent EIAV demonstrate distinct biological properties

Biologic activity of equine infectious anemia virus (EIAV) surface (SU) glycoprotein was assayed in a mouse model. Recombinant SU from virulent EIAV17 (SU17), administered intraperitoneally to mouse pups, induced dose-dependent diarrheal responses similar to those reported for SIV SU (Virology 277 (2000) 250). SU17 caused fluid accumulation without histological lesions in mouse intestinal loops, induced chloride secretory currents in Ussing chambers and increased inositol 1,4,5 triphosphate (IP3) levels in HT29 cells. An SU17 peptide, SU17(299-330), provoked a dose-dependent diarrheal response akin to enterotoxic peptides from SIV. In contrast, SU from an avirulent EIAV strain failed to induce a dose response in mouse pups and produced lower levels of activity than SU17 in Ussing chambers and IP3 assays. These results demonstrate that a mouse pup model is useful to monitor EIAV SU biologic activity, showing clear differences between the activities of SU derived from virulent and avirulent viruses, and may provide a useful screen of EIAV virulence.

Noise-induced impulse pattern modifications at different dynamical period-one situations in a computer model of temperature encoding

We used a minimal Hodgkin-Huxley type model of cold receptor discharges to examine how noise interferes with the non-linear dynamics of the ionic mechanisms of neuronal stimulus encoding. The model is based on the assumption that spike-generation depends on subthreshold oscillations. With physiologically plausible temperature scaling, it passes through different impulse patterns which, with addition of noise, are in excellent agreement with real experimental data. The interval distributions of purely deterministic simulations, however, exhibit considerable differences compared to the noisy simulations especially at the bifurcations of deterministically period-one discharges. We, therefore, analyzed the effects of noise in different situations of deterministically regular period-one discharges: (1) at high-temperatures near the transition to subthreshold oscillations and to burst discharges, and (2) at low-temperatures close to and more far away from the bifurcations to chaotic dynamics. The data suggest that addition of noise can considerably extend the dynamical behavior of the system with coexistence of different dynamical situations at deterministically fixed parameter constellations. Apart from well-described coexistence of spike-generating and subthreshold oscillations also mixtures of tonic and bursting patterns can be seen and even transitions to unstable period-one orbits seem to appear. The data indicate that cooperative effects between low- and high-dimensional dynamics have to be considered as qualitatively important factors in neuronal encoding.

[The study of beta-2 adrenergic receptors gene transferred into cardiomyocytes by adenovirus vectors contain different promoter]

OBJECTIVE

To observe human beta(2) adrenergic receptors (beta(2)-AR) gene expression in cardiomyocytes transfected by adenoviral vector contain cmv or mlc-2v promoter.

METHODS

Two adenoviral vectors (Adcmv beta(2) AR, Admlc beta(2) AR) were constructed, in which beta(2)-AR gene is under control of either the ventricle-specific myosin light chain-2 (mlc-2v) or the cmv promoter. The cultured neonate rat ventricular myocytes were infected by two adenoviral vectors, and the beta(2)-AR expression of on cultured neonate rat ventricular myocytes and their ability to potentiate beta-adrenergic signaling were assessed.

RESULTS

The presence of beta(2)-AR mRNA was detected by RT-PCR, and the expression of the beta(2)-AR gene was demonstrated by protein immunoblots. According to a ligand binding assay, the density of beta-AR in the cardiomyocytes infected by Admlc beta(2) AR and Adcmv beta(2) AR was greater than that in the control. Moreover, the latter was higher than the former (234 +/- 6.4 fmol/mg protein vs 153 +/- 5.2 fmol/mg protein) (P < 0.01). It was demonstrated that beta(2)-AR gene significantly increased isoproterenol stimulated cAMP in cardiomyocytes.

CONCLUSION

The results above demonstrated that human beta(2)-AR gene was expressed in the cardiomyocytes infected by recombinant adenovirus contain cmv or mlc-2v promoter, but both is different.

[Expression of recombinant human Flt3 ligand in Escherichia coli and its purification and characterization]

OBJECTIVE

To establish a highly efficient expression system of recombinant human Flt3 ligand (rhFL) in E. coli and a suitable purification method of the expressed products.

METHOD

Human FL encoding cDNA was introduced into pProEXHT plasmid to express a 6 x His-FL fusion protein in E. coli. The fusion protein expressed in inclusion body was isolated, solubilized and refolded, and then purified by chromatography on a metal-chelating affinity column (MCAC). Its activity was detected by stimulating the proliferation of CD(34)(+) cells.

RESULT

The amount of rhFL expressed was about 15% of total bacterial proteins and the purity of rhFL was 90% after MCAC. The combination of rhFL, granulocyte colony-stimulating factor and erythropoietin could stimulate CD(34)(+) cells to a 400 fold expansion.

CONCLUSION

The purified rhFL had a potent activity to stimulate hematopoietic stem cells to expanse in vitro.

Paddlefish strike at artificial dipoles simulating the weak electric fields of planktonic prey

The freshwater paddlefish Polyodon spathula (Polyodontidae) feeds primarily on the water flea (Daphnia sp.), and previous studies suggest that these fish detect their planktonic prey using their rostral electrosensory system. Zooplankton produce direct-current and oscillating alternating-current electric fields containing multiple frequencies and amplitudes. We asked whether an inanimate electric field is sufficient to elicit paddlefish strikes equivalent to their feeding behavior. Juvenile paddlefish respond to artificial dipole stimuli by investigating the electric field and striking at the dipole electrode tips. These behavioral responses, scored as strikes, exhibit a bandpass characteristic with a maximum response between 5 and 15 Hz. Responses were less frequent at higher (20, 30, 40, 50 Hz) and lower (0.1, 0.5, 1 Hz) test frequencies, with a steep drop-off below 5 Hz. Strike rates also varied with stimulus intensity. Response frequency was greatest at 0.25 microA peak-to-peak amplitude, with reduced responses at lower and higher amplitudes (0.125 and 1.25 microA). Striking behavior was also influenced by water conductivity: strike rate was reduced at higher water conductivity. Dipole-elicited strikes exhibit behavioral plasticity. Fish habituate to repetitive dipole stimuli that are not reinforced by prey capture, and they dishabituate after food reinforcement. These experiments characterize paddlefish feeding strikes towards dipole electrodes at signal frequencies and intensities simulating the electric fields of zooplankton, their natural prey, and demonstrate that electric fields are sufficient to elicit feeding behavior. The results support the conclusion that paddlefish use their passive electrosensory system for planktivorous feeding.

[Expression of lipofect AMINE mediated human GM-CSF eukaryotic expressing vector in HFCL cells]

OBJECTIVE

To construct an eukaryotic expressing vector-pIRES1neo/hGM-CSF and express it in human bone marrow stromal cell line HFCL.

METHODS

Human granulocyte/macrophage colony-stimulating factor cDNA (hGM-CSF cDNA, 751 bp) was inserted into an effective eukaryotic expressing vector-pIRES1neo which contains the human cytomegalovirus (CMV) major immediate early promoter/enhancer and the internal ribosome entry site (IRES) of the encephalomyocarditis virus (ECMV). HFCL cells were transfected with the recombinant vector pIRES1neo/hGM-CSF by liposome-mediated gene transfer method. Integration of hGM-CSF in the genome, transcription of its mRNA and expression of its protein in the transfected HFCL cells were assayed by Southern blot, Northern blot, ELISA and hGM-CSF dependent cell line TF-1.

RESULTS

hGM-CSF cDNA was integrated into HFCL genome successfully, hGM-CSF mRNA was transcripted and hGM-CSF protein was expressed of (56.9 +/- 0.7) ng/10(6) cells by ELISA and (6.56 +/- 0.16) x 10(3) U/10(6) cells per day by TF-1 cell assay in the supernatant.

CONCLUSION

The recombinant vector is proved to be stably expressed in HFCL cells and the biological activity of hGM-CSF was detectable in the supernatant of the transfected cells.

[Experimental studies on the characteristics of suicide gene system HSV-tk/GCV and its effect on dendritic cells]

OBJECTIVE

To study the characteristics of suicide gene system of the herpes simplex virus thymidine kinase (HSV-tk) gene in tumor cells and explore the apoptosis phenomena in this system and its effect on dendritic cells (DC).

METHOD

HSV-tk was transduced into the breast cancer cell line MCF-7 cells with a retrovirus vector. Apoptosis was examined by electro-microscopy and FACS. DCs were induced from cord blood CD(34)(+) cells with a combination of cytokines (GM-CSF, TNF-alpha, SCF and FL) and (3)H-TdR was adopted to determine the proliferation of T cells.

RESULTS

In vitro experiment showed a dose-dependent cell killing of the HSV-tk gene transducted cells on ganciclovir (GCV) treatment. The apoptosis rate increased to 31.3% from the control group of 19.3%. Apoptosis is the important mechanism in bystander effect of HSV-tk/GCV system. The CD(1a)(+) and HLA-DR(+) cells in the induced DC were of (27.18 +/-1.56)% and (93.7 +/- 1.0)%, respectively. Co-incubation of DC with apoptotic cells further stimulated the proliferation of T cells.

CONCLUSION

It suggested that HSV-tk/GCV system, alone or combined with radiotherapy, be a promising suicide gene therapy for cancer patient and an approach to enhancing DC function.

[Epidemiological studies on the relationship between body weight and the prevalence rate of impaired glucose tolerance (IGT) in the population of urban areas of Tianjin city]

OBJECTIVE

In order to explore the relationship between body weight and the prevalence rate of IGT in a community - based population and to provide scientific informations of IGT for prevention and control.

METHODS

Cluster sampling was carried out in prevalence survey, together with clinical examination and test of blood plasma glucose.

RESULTS

A sample of 62,577 people was performed by cluster random sampling. Results showed that the crude prevalence rate of IGT in the whole population of three communities was 13.13 per thousand in males, 19.18 per thousand in females, and 16.23 per thousand in both sexes respectively. The IGT prevalence rate of different body weight group in community population had a marked difference. There was a trand that the IGT prevalence rate increased markedly with the increase of body weight.

CONCLUSION

The incidence of IGT is related to body weight and obesity.

Old age support in China: the role of the state and the family

This study investigates the relationship between some support factors and the well-being of the elderly in China. The analytical models identify and compare the effects of each type of factor on the sense of well-being of elderly Chinese across rural and urban settings. Pension, health care, size of family, and living arrangements are the factors found to be significantly related to the perception of happiness among aged people in general. The strength of the effects of children and living arrangements varies depending on places of residency. The findings indicate the continuous role of the family support, and the increasingly important role of state support in promoting a sense of well-being among elderly Chinese.

[Effect of WT1 antisense oligonucleotide on proliferation and apoptosis of human leukemia cells]

OBJECTIVE

To elucidate the effect of WT1 antisense oligonucleotide on and the role of WT1 gene in proliferation and apoptosis of leukemia cells.

METHODS

K562, U937, HL-60 cell lines, leukemic blast from 8 acute myeloid leukemia patients and normal bone marrow cells from 8 healthy subjects were treated in vitro with WT1 antisense oligonucleotide (WT1 ASO) targeting to the translation site of WT1 mRNA. The inhibitory effect on growth of leukemia cells was measured by Trypan blue exclusion and colony-forming unit assay. Apoptosis was measured by flow cytometric analysis and DNA fragmentation assay.

RESULTS

WT1 ASO significantly inhibited the proliferation of K562 cells expressing WT1 and leukemic blast of 4 in 8 acute myeloid leukemia patients, but didn't inhibit the growth of U937 cells which had no WT1 expression and CFU-GM of normal marrow cells from 8 healthy subjects. Whereas WT1 sense oligonucleotide (WT1 SO) had no effect on the proliferation of K562 cells, U937 cells and the CFU-GM of normal marrow cells. WT1 ASO could induce apoptosis of K562 cells and the level of apoptosis was increased markedly when combined with Vp16; WT1 ASO alone couldn't induce apoptosis of HL-60 cells, but could increase the apoptosis when combined with Vp16.

CONCLUSION

WT1 ASO specifically inhibit the growth of leukemic cells, induce apoptosis of K562 cells and increase the apoptosis susceptibility of leukemia cells to Vp16. WT1 plays an important role in proliferation and apoptosis of leukemic cells.

[Studies on hematopoietic reconstitution by ex vivo expanded human cord blood hematopoietic stem/progenitor cells in SCID mice]

OBJECTIVE

To elucidate the effect of the combination of cytokines on ex vivo expansion and self-renewal potential of human umbilical cord blood hematopoietic stem/progenitor cells.

METHODS

CD34+ cells from cord blood were expanded for 14 days in the culture containing FL + Tpo + SCF + IL-6 + IL-3 + G-CSF and the expanded cells were transplanted into sublethally irradiated SCID mice.

RESULTS

The expanded cells were engrafted smoothly in the SCID recipients and reconstituted their hematopoiesis. Furthermore, human hematopoietic cells could be detected in the marrow of the recipients 6 weeks after transplantation.

CONCLUSION

It is possible to expand hematopoietic cells ex vivo efficiently and maintain concomitantly their self-renewal and hematopoietic reconstitution capacities by the combination of FL + Tpo + SCF + IL-6 + IL-3 + G-CSF.

Who is hematopoietic stem cell: CD34+ or CD34-?

Hematopoietic stem cells (HSC) possess multipotentiality, enabling them to self-renew and also to produce mature blood cells, such as erythrocytes, leukocytes, platelets, and lymphocytes. CD34 is a marker of human HSC, and all colony-forming activity of human bone marrow (BM) cells is found in the CD34+ fraction. Clinical transplantation studies that used enriched CD34+ BM cells indicated the presence of HSC with long-term BM reconstitutional ability within this fraction. But recent studies in NOD/SCID mice, rhesus monkeys, and human/sheep competitive engraftment models have provided evidence for the presence of a rare cell population that contains progenitors capable of producing CD34+ cells in vitro. These progenitors are highly enriched in HSC and have competitive long-term in vivo repopulating potential devoid of both CD34 and lineage-marker expression. These new findings add to the growing evidence that some stem cells in the BM do not express the CD34 marker, which is currently used to select stem cells for transplantation.

[Studies on the properties of dendritic cells from cord blood CD34+ cells and peripheral blood monocytes]

OBJECTIVE

Ex vivo expansion and purification of dendritic cells(DC) with typical phenotype, morphology and function are critical to the further studies on DC and their clinical application.

METHODS

CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and peripheral blood mononuclear cells (PBMC) were depleted of T and B cells by mixing them with T/CD2 and B/CD19 magnetic beads. DC were induced and expanded with different combinations of cytokines. They were identified for their properties by FACS, electronic microscopy, microscopy, and mixed lymphocyte reaction (MLR).

RESULTS

Cultures of cord blood CD34+ cells with the combination of GM-CSF + TNF-alpha + SCF + FL yielded (27.18 +/- 1.56)% CD1a+ cells, much higher than that (0.65 +/- 0.38)% with GM-CSF alone. The combination of GM-CSF and high dose IL-4(1,000 U/ml) was the most potential for expanding CD1a+ cells [(21.8 +/- 0.32)%] for PBMC. Both of the DC from different sources were similar in phenotype and morphology, and had the capacity to stimulate proliferation of allogeneic T lymphocytes.

CONCLUSION

Both of cord blood and peripheral blood are the source for generation of a large number of typical DC, and can be adopted for the application according to different purposes. These results lay foundation for the immunotherapy with DC.

The in vitro antiapoptotic effect of dehydroepiandrosterone sulfate in mouse thymocytes and its relation to caspase-3/caspase-6

The effects of dehydroepiandrosterone sulfate (DHEAS) on thymocyte apoptosis induced by dexamethasone (DEX) were investigated. Apoptosis was measured by using agarose gel electrophoresis of DNA, the terminal deoxynucleotidyltransferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry. Our results showed that preincubation with 1 x 10(-4) M DHEAS protected thymocytes from DEX-induced apoptosis in vitro. Moreover, we found no blocking effect on the DEX-induced activation of caspase-3 and caspase-6 by the preincubation of thymocytes with DHEAS. This may be interpreted to mean that the antagonism of DHEAS to DEX-induced apoptosis is not related to the activation of these down-stream caspases which play a critical role in the execution of apoptosis.

[One-time operation in infant cleft lip and palate plus alveolar process]

OBJECTIVE

To improve safety and viability of one-time operation in the therapy of cleft lip and palate and cleft alveolar process.

METHODS

Under the air-vein anesthesia, one-time operations were performed in 42 patients with complete cleft lip and palate plus cleft alveolar process. After rehabilitation in ICU, all patients were put into wards, and left hospital 4-7 days after operation.

RESULTS

The situation during anesthesia and operation was good. There were no statistically significant changes in blood pressure, oxygen saturation of blood, heart rate and cardiac rhythm before, during and after operation. No anesthetic accident and no complication happened. The loss of blood was about 42.7 +/- 6.5 ml and the duration of operation was about 139.2 +/- 18.6 minutes. The rehabilitation was successful after operations. First intention took place in almost all patients' incisions, and palatal fistulas appeared in only 2 cases.

CONCLUSION

Under the control of provisioned pediatric anesthesia and rehabilitation, one-time complete cleft lip and palate plus cleft alveolar process closure is safe and viable.

[Retroviral-mediated transfer of a hygromycin phosphotransferase-thymidine kinase fusion gene into human bladder carcinoma cell]

OBJECTIVE

To evaluate the therapeutic efficacy of retroviral-mediated hygromycin phosphotransferase-thymidine kinase fusion gene (HyTK)/GCV on human bladder carcinoma cell.

METHODS

A retroviral expression vector pL (HyTK) SN was constructed. By using FuGENE 6-mediated transfection and "ping-pong effect" technique, high-titer of retroviral supernatant was obtained and HyTK gene was transferred into EJ cells. A retroviral vector encoding, enhanced green fluorescent protein, EGFP was used to rapidly detect the transduction efficiency. Antitumor effects were observed after GCV treatment.

RESULTS

In vitro experiments demonstrated the EJ cells transferred by HyTK gene were killed in the GCV treatment. Non-transduced parental cells were not sensitive to GCV, but they were dead by the bystander killing of neighboring cells when mixed with EJ/HyTK cells at various ratios. In addition, this not only affect wild-type EJ cells but also cells from different bladder carcinoma cell lines.

CONCLUSIONS

Retroviral-mediated HyTK/GCV systems were a promising suicide gene therapy for bladder carcinoma. EGFP may act as a convenient and rapid reporter to monitor retroviral-mediated gene transfer and expression in bladder carcinoma cells.

[Engineering of hematopoietic cells and the hematopoietic reconstitution of expanded cells in SCID mice]

OBJECTIVE

To elucidate the roles of cytokines for ex vivo expansion and orderly differentiation of hematopoietic progenitor cells, and the capacity of hematopoietic reconstitution of the expanded cells.

METHODS

CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and expanded with the different combinations of cytokines in a liquid culture system. The expanded cells were then transplanted into sublethally irradiated SCID mice.

RESULTS

The combination of cytokines including FL, SCF, TPO, etc. increased total cells, progenitor cells(CFU-GM and CFU-MK), and CD34+ CD38- early progenitor cells by (2,130 +/- 57), (70 +/- 7), (118 +/- 11) and (46 +/- 5) folds, respectively. The percentage of dendritic cells (24.3 +/- 2.1)% was also much higher than the control(0.4 +/- 0.3)%. The CD34+ CD38- subsets and the combination of FL and TPO were identified as the most potential for expanding early progenitor cells. The expanded cells could smoothly engraft SCID recipients and reconstitute their hematopoiesis. Furthermore, human hematopoietic cells and could be detected in marrow cells from SCID mice transplanted 6 weeks late.

CONCLUSIONS

It is possible to expand hematopoietic cells ex vivo efficiently and maintain the hematopoietic reconstitution capacities of hematopoietic stem/early progenitor cells by an appropriate combination of cytokines. The engineering of hematopoietic cells--the new generation of cellular therapeutics are now underway in the applications of stem cell transplantation, immunotherapy of cancers, and gene therapy.

Low-dimensional dynamics in sensory biology 2: facial cold receptors of the rat

We report the results of a search for evidence of unstable periodic orbits in the sensory afferents of the facial cold receptors of the rat. Cold receptors are unique in that they exhibit a diversity of action potential firing patterns as well as pronounced transients in firing rate following rapid temperature changes. These characteristics are the result of an internal oscillator operating at the level of the membrane potential. If such oscillators have three or more degree of freedom, and at least one of which also exhibits a nonlinearity, they are potentially capable of complex activity. By detecting the existence of unstable periodic orbits, we demonstrate low-dimensional dynamical behavior whose characteristics depend on the temperature range, impulse pattern, and temperature transients.

Implications for function and therapy of a 2.9 A structure of binary-complexed antithrombin

The crystal structure of a binary complex of human antithrombin with a peptide of the same sequence as its reactive loop (P14-P3) has been determined at 2.9 A. The peptide binds as the middle strand s4A in the A beta-sheet, homologously to that of the reactive loop in the latent and cleaved forms of antithrombin. Peptide binding results in the complete expulsion of the hinge region of the loop from the A beta-sheet although the conformation differs from that of heparin-activated antithrombin. The 36-fold increase in the rate of reaction of the binary complex with factor Xa indicates that full loop expulsion alone is not sufficient for complete heparin activation of antithrombin but that this is also dependent on the overall conformation of the molecule. Previous studies have demonstrated that reactive loop peptides can block or reverse the polymerisation of serpins associated with cirrhosis and thrombosis. The antithrombin binary complex structure defines the precise localisation of the blocking peptide in a serpin and provides the basis for rational drug design for mimetics that will prevent polymerisation in vivo and so ameliorate the associated disease.