SDF-1/CXCL12 enhances survival and chemotaxis of murine embryonic stem cells and production of primitive and definitive hematopoietic progenitor cells

Understanding embryonic stem cell (ESC) regulation is important for realizing how best to control their growth and differentiation ex vivo for potential therapeutic benefit. Stromal cell-derived factor-1 (SDF-1/CXCL12) and its receptor, CXCR4, have been implicated as important regulators of a number of fetal and adult cell functions, including survival/antiapoptosis and migration/homing of hematopoietic stem and progenitor cells. We hypothesized that the SDF-1/CXCL12-CXCR4 axis would also be important for regulation of murine ESC functions. ESCs secreted low levels of SDF-1/CXCL12 and expressed low levels of CXCR4; however, both increased with differentiation of ESCs. Endogenously produced/released SDF-1/CXCL12 enhanced survival/antiapoptosis of ESCs in the presence of leukemia inhibitory factor but absence of serum, and survival/antiapoptosis was further enhanced by exogenous administration of SDF-1/CXCL12. Furthermore, SDF-1/CXCL12 induced chemotaxis of ESCs, and chemotaxis could be enhanced by diprotin A inhibition of CD26/dipeptidylpeptidase IV. Endogenous and exogenous SDF-1/CXCL12 enhanced embryoid body production of primitive and definitive erythroid, granulocyte-macrophage, and multipotential progenitors. SDF-1/CXCL12 did not noticeably affect production of hemangioblasts. These results demonstrate functional activities of SDF-1/CXCL12 on survival, chemotaxis, and hematopoietic differentiation of murine ESCs that may be relevant for their ex vivo manipulation.

Adenovirus binding to cultured synoviocytes triggers signaling through MAPK pathways and induces expression of cyclooxygenase-2

BACKGROUND

Recombinant adenovirus can be administered in vivo to achieve transduction of a number of cell types including human synoviocytes. Immunogenicity of adenoviruses has limited their utility as vectors for gene delivery; however, specific mechanisms underlying the acute inflammatory response to adenovirus are not well understood. Activation of a number of signal transduction pathways occurs rapidly upon adenovirus binding to cell-surface receptors. We investigated stimulated expression of mitogen-activated protein kinases (MAPKs), cyclooxygenase-2 (COX-2) and prostaglandin E(2) (PGE(2)) in human primary synovial fibroblasts to adenovirus expressing the E. coli beta-galactosidase gene.

METHODS

Cultured rheumatoid synoviocytes were exposed to transduction-competent Ad/RSVlacZ recombinant adenovirus or transduction-incompetent (psoralen/UV-irradiated) Ad/RSVlacZ. The effects on COX-2 expression, PGE(2) levels and MAPK signaling in synoviocytes were assessed using a combination of reverse-transcription polymerase chain reaction amplification and immunoblotting.

RESULTS

Adenovirus treatment of synoviocytes increased levels of COX-2 mRNA and protein as well as PGE(2). Psoralen-treated transcriptionally inactive adenovirus was equivalent to untreated adenovirus for early COX-2 induction suggesting that viral genes were not required. Adenovirus treatment stimulated phosphorylation of ERK-1/-2, p38 MAPK, and JNK. Inhibition of the ERK and p38 MAPK pathways inhibited COX-2 expression and PGE(2) production.

CONCLUSIONS

Taken together, these data demonstrate that a MAPK-dependent increase in COX-2 results in local prostaglandin production. These findings have clinical implications for use of adenovirus as vectors for in vivo gene delivery.

The CXCR4 agonist peptide, CTCE-0021, rapidly mobilizes polymorphonuclear neutrophils and hematopoietic progenitor cells into peripheral blood and synergizes with granulocyte colony-stimulating factor

OBJECTIVE

Mobilization of hematopoietic stem and progenitor cells (HSPC) by stromal cell-derived factor-1 (SDF-1) has been described; however, sustained adenoviral delivery or N-terminal modification was required for effect and could not be demonstrated with native protein. The aim of this study was to further investigate the SDF-1alpha/CXCR4 axis in HSPC mobilization using CTCE-0021, a cyclized CXCR4 agonist peptide, with comparable bioactivity and improved stability relative to SDF-1alpha.

METHODS

Peripheral blood cells and hematopoietic progenitor cells (HPC) were quantitated in mice administered single or multiple doses of CTCE-0021 or SDF-1alpha, or mobilized by granulocyte colony-stimulating factor (G-CSF) in combination with CTCE-0021. Proteases, cytokines, and receptors implicated in HSPC mobilization were evaluated to determine mechanism of action.

RESULTS

CTCE-0021 dose-dependently elevated blood neutrophils polymorphonuclear neutrophil [PMN] within 5 minutes that peaked after 1 hour and persisted for 24 hours. PMN mobilization could be maintained by daily dosing. CTCE-0021 mobilized colony-forming unit granulocyte macrophage (CFU-GM), burst-forming unit erythroid (BFU-E), and CFU-granulocyte-erythrocyte-monocyte-megakaryocyte (CFU-GEMM) that peaked within 1 hour after administration, and synergistically enhanced both PMN and HSPC mobilization when combined with G-CSF. Mobilization induced by CTCE-0021 was associated with rapid downregulation of CXCR4 expression on HPC. No appreciable changes in proteases implicated in HPC mobilization were observed. Significantly elevated plasma SDF-1 was detected in mobilized mice, which likely represents CTCE-0021.

CONCLUSION

These studies indicate that CTCE-0021 is an efficient and rapid mobilizer of PMN and HPC when used alone and shows synergistic activity when used in combination with G-CSF. The mobilizing effect of this peptide appears to be mediated by downregulation of the CXCR4 receptor on HPC and altered chemokine gradient.

Neutrophil-derived MMP-9 mediates synergistic mobilization of hematopoietic stem and progenitor cells by the combination of G-CSF and the chemokines GRObeta/CXCL2 and GRObetaT/CXCL2delta4

Mobilized peripheral blood stem cells (PBSCs) are widely used for transplantation, but mechanisms mediating their release from marrow are poorly understood. We previously demonstrated that the chemokines GRObeta/CXCL2 and GRObetaT/CXCL2Delta4 rapidly mobilize PBSC equivalent to granulocyte colony-stimulating factor (G-CSF) and are synergistic with G-CSF. We now show that mobilization by GRObeta/GRObetaT and G-CSF, alone or in combination, requires polymorphonuclear neutrophil (PMN)-derived proteases. Mobilization induced by GRObeta/GRObetaT is associated with elevated levels of plasma and marrow matrix metalloproteinase 9 (MMP-9) and mobilization and MMP-9 are absent in neutrophil-depleted mice. G-CSF mobilization correlates with elevated neutrophil elastase (NE), cathepsin G (CG), and MMP-9 levels within marrow and is partially blocked by either anti-MMP-9 or the NE inhibitor MeOSuc-Ala-Ala-Pro-Val-CMK. Mobilization and protease accumulation are absent in neutrophil-depleted mice. Synergistic PBSC mobilization observed when G-CSF and GRObeta/GRObetaT are combined correlates with a synergistic rise in the level of plasma MMP-9, reduction in marrow NE, CG, and MMP-9 levels, and a coincident increase in peripheral blood PMNs but decrease in marrow PMNs compared to G-CSF. Synergistic mobilization is completely blocked by anti-MMP-9 but not MeOSuc-Ala-Ala-Pro-Val-CMK and absent in MMP-9-deficient or PMN-depleted mice. Our results indicate that PMNs are a common target for G-CSF and GRObeta/GRObetaT-mediated PBSC mobilization and, importantly, that synergistic mobilization by G-CSF plus GRObeta/GRObetaT is mediated by PMN-derived plasma MMP-9.

Highly efficient genetic transduction of primary human synoviocytes with concentrated retroviral supernatant

We are developing retroviral-mediated gene transfer to human fibroblast-like synovial cells (FLS) as one approach to characterizing genetic pathways involved in synoviocyte pathophysiology. Prior work has suggested that FLS are relatively refractory to infection by Moloney murine leukemia virus based vectors. To determine if viral titer influenced the transduction efficiency of FLS, we optimized a rapid, efficient, and inexpensive centrifugation method to concentrate recombinant retroviral supernatant. The technique was evaluated by measurement of the expression of a viral enhanced green fluorescent protein transgene in transduced cells, and by analysis of viral RNA in retroviral supernatant. Concentration (100-fold) was achieved by centrifugation of viral supernatant for four hours, with 100% recovery of viral particles. The transduction of FLS increased from approximately 15% with unconcentrated supernatant, to nearly 50% using concentrated supernatant. This protocol will be useful for investigators with applications that require efficient, stable, high level transgene expression in primary FLS.

[Summarization of studies on Chinese marine medicinal animal Syngnthus acus]

Syngnthus acus L. is a kind of very important traditional Chinese-medicine from sea. It has plentiful amino acid, protein, trace element, poly-carbon non-saturation fat acid, etc. Syngnthus acus has sexual-hormones-like, anti-cancer and resisting fatigue effects; It can resist fatigue. It can also improve organism immunity and enhance the systolic strength of heart muscle. It can be widely used in many fields such as food field, medical field and aquatic products industry. Its classification, resources, chemical composition and its medical value have been summarized in this article.

Microsomal prostaglandin E synthase is regulated by proinflammatory cytokines and glucocorticoids in primary rheumatoid synovial cells

The selective induction of PGE(2) synthesis in inflammation suggests that a PGE synthase may be linked to an inducible pathway for PG synthesis. We examined the expression of the recently cloned inducible microsomal PGE synthase (mPGES) in synoviocytes from patients with rheumatoid arthritis, its modulation by cytokines and dexamethasone, and its linkage to the inducible cyclooxygenase-2. Northern blot analysis showed that IL-1beta or TNF-alpha treatment induces mPGES mRNA from very low levels at baseline to maximum levels at 24 h. IL-1beta-induced mPGES mRNA was inhibited by dexamethasone in a dose-dependent fashion. Western blot analysis demonstrated that mPGES protein was induced by IL-1beta, and maximum expression was sustained for up to 72 h. There was a coordinated up-regulation of cyclooxygenase-2 protein, although peak expression was earlier. Differential Western blot analysis of the microsomal and the cytosolic fractions revealed that the induced expression of mPGES protein was limited to the microsomal fraction. The detected mPGES protein was catalytically functional as indicated by a 3-fold increase of PGES activity in synoviocytes following treatment with IL-1beta; this increased synthase activity was limited to the microsomal fraction. In summary, these data demonstrate an induction of mPGES in rheumatoid synoviocytes by proinflammatory cytokines. This novel pathway may be a target for therapeutic intervention for patients with arthritis.

[The sonochemical-degradation mechanism of toluene in aqueous solution]

The sonochemical degradation of toluene in the airproof aqueous solution was studied, and the mechanism and course of degradation was explored. It was found that the sonication time had great effect on the removal rate of toluene, and the degradation followed a pseudo-first-order kinetic law, and 90%-95% of toluene was removed only after being irradiated for 40 min, types of dissolved gas and pH also had some effects. After aqueous solution was analyzed pH and scanned UV-wavelength and identified components with SMPE-GC-MS, results confirmed that radical-oxidation controlled the sonochemical-oxidation of toluene, and main middle-products included benzaldehyde, bibenzyl, dibutyl phthalate, et al., final products were carbon dioxide and water.

[The clinical importance of persistent elevation of electrocardiographic ST segment in acute myocardial infarction patients after reperfusion therapy]

OBJECTIVE

To observe the clinical importance of persistent elevation of electrocardiographic ST segment in acute myocardial infarction (AMI) patients receiving direct percutaneous transluminal coronary angioplasty (PTCA).

METHODS

Thirty patients with a first AMI successfully treated with direct coronary angioplasty were selected. The extent of the ST segment elevation and resolution in electrocardiograms on admission and one hour after direct PTCA was analyzed. All the patients were divided into two groups according to the extent of ST segment elevation and resolution. Group A: resolution of ST segment elevation >or=50%, n = 19; Group B: resolution of ST segments elevation < 50%, n = 11. Low-dose dobutamine stress echocardiogram was taken at (7 +/- 2) days after AMI and echocardiogram checked at 1, 2 and 3 months after AMI.

RESULTS

Left ventricular ejection fraction (LVEF) in group A was higher than that in group B at the first week and the first, second and third month after AMI. Aortic blood peak acceleration, cardiac output and cardiac output index of group A were all significantly higher than those in group B at stress. Global wall motion score index (GWMSI) and infarct-zone wall motion score index (IWMSI) in group A were smaller than those in group B at baseline and stress. GWMSI in group A was smaller than that in group B at 1, 2 and 3 months after AMI. There was no significant difference of IWMSI between group A and group B at 1 and 2 months after AMI. IWMSI in group A was smaller than that in group B at the third month after AMI.

CONCLUSIONS

The patients in group B had lower left ventricular contractile function and contractile reserve function and less recovery of infarct-zone wall motion than that in group A.

Critical role of C/EBPdelta and C/EBPbeta factors in the stimulation of the cyclooxygenase-2 gene transcription by interleukin-1beta in articular chondrocytes

The activity of the [-831; +103] promoter of the human cyclooxygenase-2 gene in cultured rabbit chondrocytes is stimulated 2.9 +/- 0.3-fold by interleukin-1beta and this stimulation depends on [-132; -124] C/EBP binding-and [-223; -214] NF-kappaB binding-sites. The C/EBPbeta and C/EBPdelta factors bind to the [-132; -124] sequence. The [-61; -53] sequence is also recognized by C/EBPbeta and C/EBPdelta as well as USF. Mutation of the whole [-61; -53] sequence abolished the stimulation of transcription but single mutations of the C/EBP or USF site did not alter the activity of the promoter, suggesting that the factors bound to the proximal [-61; -53] sequence interact with different members of the general transcription machinery. The [-223; -214] site binds only the p50/p50 homodimer and a non-rel-related protein, but not the transcriptionally active heterodimer p50/p65. The p50/p50 homodimer could interact with the C/EBP family members bound to the [-132; -124] sequence for full stimulation of the COX-2 transcription by interleukin-1beta in chondrocytes. By contrast, the [-448; -449] sequence binds with a low affinity both the p50/p50 homodimeric and p50/p65 heterodimeric forms of NF-kappaB but has no role in the regulation of the human COX-2 promoter in chondrocytes.

Alloantibody-mediated class I signal transduction in endothelial cells and smooth muscle cells: enhancement by IFN-gamma and TNF-alpha

Chronic rejection is the major limiting factor to long term survival of solid organ allografts. The hallmark of chronic rejection is transplant atherosclerosis, which is characterized by the intimal proliferation of smooth muscle cells, endothelial cells, and fibroblasts, leading to vessel obstruction, fibrosis, and eventual graft loss. The mechanism of chronic rejection is poorly understood, but it is suspected that the associated vascular changes are a result of anti-HLA Ab-mediated injury to the endothelium and smooth muscle of the graft. In this study we have investigated whether anti-HLA Abs, developed by transplant recipients following transplantation, are capable of transducing signals via HLA class I molecules, which stimulate cell proliferation. In this report we show that ligation of class I molecules with Abs to distinct HLA-A locus and HLA-B locus molecules results in increased tyrosine phosphorylation of intracellular proteins and induction of fibroblast growth factor receptor expression on endothelial and smooth muscle cells. Treatment of cells with IFN-gamma and TNF-alpha up-regulated MHC class I expression and potentiated anti-HLA Ab-induced fibroblast growth factor receptor expression. Engagement of class I molecules also stimulated enhanced proliferative responses to basic fibroblast growth factor, which augmented endothelial cell proliferation. These findings support a role for anti-HLA Abs and cytokines in the transduction of proliferative signals, which stimulate the development of myointimal hyperplasia associated with chronic rejection of human allografts.

HLA class I-mediated induction of cell proliferation involves cyclin E-mediated inactivation of Rb function and induction of E2F activity

Chronic rejection of transplanted organs is manifested as atherosclerosis of the blood vessels of the allograft. HLA class I Ags have been implicated to play a major role in this process, since signaling via HLA class I molecules can induce the proliferation of aortic endothelial as well as smooth muscle cells. In this study, we show that HLA class I-mediated induction of cell proliferation correlates with inactivation of the Rb protein in the T cell line Jurkat as well as human aortic endothelial cells. HLA class I-mediated inactivation of Rb can be inhibited specifically by neutralizing Abs to basic fibroblast growth factor (bFGF), suggesting a role for FGF receptors in the signaling process. Signaling through HLA class I molecules induced cyclin E-associated kinase activity within 4 h in quiescent endothelial cells, and appeared to mediate the inactivation of Rb. A cdk2 inhibitor, Olomoucine, as well as a dominant-negative cdk2 construct prevented HLA class I-mediated inactivation of Rb; in contrast, dominant-negative cdk4 and cdk6 constructs had no effect. Furthermore, there was no increase in cyclin D-associated kinase activity upon HLA class I ligation, suggesting that cyclin E-dependent kinase activity mediates Rb inactivation, leading to E2F activation and cell proliferation.

Ligation of HLA class I molecules on smooth muscle cells with anti-HLA antibodies induces tyrosine phosphorylation, fibroblast growth factor receptor expression and cell proliferation

The development of transplant atherosclerosis, a manifestation of chronic rejection, is the major obstacle to long-term survival of cardiac and renal allografts. The incidence of transplant atherosclerosis is increased in transplant recipients producing antidonor HLA antibodies following transplantation, suggesting that anti-HLA antibodies play a role in the pathogenesis of the disease. We have postulated that anti-HLA antibodies mediate the development of transplant atherosclerosis by binding to class I molecules on the endothelium and smooth muscle of the graft and transducing signals which stimulate cell proliferation. In this report we demonstrate that anti-HLA class I antibodies transduce signals in smooth muscle cells stimulating increased tyrosine phosphorylation of intracellular proteins and up-regulation of fibroblast growth factor (FGF) receptors. Antibody binding to class I molecules on smooth muscle cells is also accompanied by increased responsiveness to basic FGF and augmented cell proliferation. These findings may explain the increased occurrence of transplant atherosclerosis in recipients producing anti-donor HLA antibodies.

Induction of high affinity fibroblast growth factor receptor expression and proliferation in human endothelial cells by anti-HLA antibodies: a possible mechanism for transplant atherosclerosis

The major limitation to long term survival of organ allografts is chronic rejection, which is manifested as atherosclerosis of the vessels of the transplanted organ. There is a significant association between transplant atherosclerosis and the development of Abs to the disparate HLA Ags present on the graft vasculature. We have investigated the effect of anti-HLA Abs on endothelial cells (EC) and smooth muscle cells cultured in vitro. Ab ligation of class I molecules on ECs results in increased high affinity fibroblast growth factor receptor mRNA expression, and enhanced basic fibroblast growth factor ligand binding. Ab binding to class I molecules on EC and smooth muscle cells is also accompanied by augmented cell proliferation. These results suggest that the intimal thickening observed in transplant atherosclerosis is the result of the proliferative effects of anti-HLA Abs.

Induction of high affinity fibroblast growth factor receptor expression and proliferation in human endothelial cells by anti-HLA antibodies: a possible mechanism for transplant atherosclerosis

The major limitation to long term survival of organ allografts is chronic rejection, which is manifested as atherosclerosis of the vessels of the transplanted organ. There is a significant association between transplant atherosclerosis and the development of Abs to the disparate HLA Ags present on the graft vasculature. We have investigated the effect of anti-HLA Abs on endothelial cells (EC) and smooth muscle cells cultured in vitro. Ab ligation of class I molecules on ECs results in increased high affinity fibroblast growth factor receptor mRNA expression, and enhanced basic fibroblast growth factor ligand binding. Ab binding to class I molecules on EC and smooth muscle cells is also accompanied by augmented cell proliferation. These results suggest that the intimal thickening observed in transplant atherosclerosis is the result of the proliferative effects of anti-HLA Abs.

Anti-HLA antibody ligation to HLA class I molecules expressed by endothelial cells stimulates tyrosine phosphorylation, inositol phosphate generation, and proliferation

The major threat to long-term survival of solid organ allografts is chronic rejection. Progressive narrowing and ultimate luminal occlusion of the arteries and arterioles of the transplanted organ are the hallmarks of the disease. The mechanism of chronic rejection is poorly understood, but it is suspected that the associated vascular changes are a result of anti-HLA antibody-mediated injury to the endothelium. We have postulated that anti-HLA antibodies initiate chronic rejection by binding to class I molecules on the endothelium and transducing signals that result in endothelial cell activation and proliferation. Our data demonstrate that anti-HLA class I antibodies transduce signals in endothelial cells stimulating increased tyrosine phosphorylation of intracellular proteins. Antibody binding to class I antigens also leads to the generation of inositol phosphate and endothelial cell proliferation. These results indicate that anti-HLA antibodies can deliver functionally important signals to endothelial cells, a finding that may be fundamental to an understanding of the mechanisms of chronic rejection.

[Effects of buyang huan wu decoction on rat hyperlipemia model]

Buyang Huan Wu Decoction can obviously lower the blood-lipid in rat hyperlipemia model, as well as drop the cholesterol in the aortic wall. Moreover, the decoction can drop the rising specific viscosity of blood and plasma, raise SOD and lower LPO in the blood.

Transient cold shock induces the heat shock response upon recovery at 37 degrees C in human cells

We evaluated the effects of a transient cold shock followed by recovery and incubation at 37 degrees C on the regulation of heat shock gene expression in the IMR-90 human diploid fibroblasts and HeLa cells in tissue culture. We showed that preincubation of cells at 4 degrees C induced the synthesis and accumulation of the heat shock proteins (HSPs) upon recovery at 37 degrees C, and the degree of this induction was directly related to the time that the cells spent at 4 degrees C. Assays on the abundance of the hsp 70 transcript, the hsp 70 gene promoter activity, and the trimerization and activation of heat shock factor (HSF) to bind to its consensus heat shock element (HSE) provided evidence that this induction of the heat shock response in cells recovering from a transient cold shock is attributable to a transcriptional event mediated by the activation of HSF. Further, the induction was a response to the temperature upshift from 4 to 37 degrees C as opposed to the 4 degrees C treatment itself; quantitation of the HSE-binding activity of cells incubated at 4 degrees C without recovery and incubation at 37 degrees C gave no evidence of an activated response. Analysis of the effects of protein synthesis inhibitors demonstrated that neither cycloheximide nor puromycin was effective in blocking the induction of HSE-binding activity in cells recovering from a transient cold shock. Experiments on the time course and temperature dependence of this induction of HSE-binding activity showed that the onset, magnitude, and duration of this induction were directly proportional to the severity of the cold stress (measured by time and temperature). We discuss the possible mechanism(s) involved in this induction of the heat shock genes at 37 degrees C by a transient cold shock and the biological implications of this observation.