[Chimeric Ad5F35 adenoviral vector-mediated expression of mutant IκBα induces apoptosis of leukemia cells].

Constitutive activation of nuclear transcription factor-κB (NF-κB) exists in a variety of leukemia, and induction of apoptosis through blocking NF-κB activation may be an alternative strategy for leukemia treatment. The aim of this study was to investigate the inducing effect of modified adenovirus 5-based adenovirus vector (i.e. chimeric Ad5F35 Vec)-mediated expression of mutant IκBα (IκBαDN) on apoptosis of HL-60 cells. The recombinant Ad5F35-IκBαDN Vec carrying IκBαDN cDNA which deleted the first 1-70 amino acids coding sequences at 5' terminal of human IκBα was transfected into HL-60 cells. The apoptosis, NF-κB DNA binding activity, the expressions of IκBα, cIAP-2 and xIAP in HL-60 cells were detected by DNA binding assay, flow cytometry, real-time quantitative polymerase chain reaction and Western blot respectively. The results showed that apoptosis rates were 22.53 ± 2.999%, 6.08 ± 2.464% and 4.86 ± 1.366% for Ad5F35-IκBαDN Vec-infected or blank vector of Ad5F35-EGFP Vec-transfected and untransfected HL-60 cells respectively, which showed a significant difference between Ad5F35-IκBαDN Vec-transfected and untransfected cells (p < 0.001) and between Ad5F35-IκBαDN Vec-transfected and Ad5F35-EGFP Vec-transfected cells (p < 0.001, p < 0.002), while NF-κB DNA binding activity was decreased, the truncated IκBα was expressed, and IκBα mRNA expression was up-regulated, but the expression of cIAP-2 and xIAP mRNA was down-regulated after transduction for 48 hours. It is concluded that the chimeric Ad5F35 Vec can effectively mediate the expression of IκBαDN cDNA in HL-60 cells, leading to the inhibition of NF-κB DNA binding activity and inducing apoptosis of HL-60 cells.

Asymmetric dimethylarginine induces tissue factor expression in monocytes via NF-kappaB-dependent pathway: Role in acute coronary syndromes.

Asymmetric dimethylarginine (ADMA), a major endogenous inhibitor of nitric oxide synthase, is recently defined as an independent cardiovascular risk factor. Tissue factor (TF) expression and procoagulant activity (PCA) of peripheral monocytes are increased in patients with acute coronary syndromes (ACS), which resulted in blood procoagulant state tending to thrombus formation. In the present study, we tested the hypothesis that ADMA contribute to TF expression of peripheral monocytes in ACS. Twenty patients with unstable angina (UA), 20 patients with stable angina (SA) and 20 control subjects were recruited. Monocytic cell line THP-1 was incubated with different concentrations of ADMA (1-10microM) for various periods (6-24h). Our results showed that plasma level of ADMA in patients with UA was significantly higher than those in patients with SA or in the control group, and positively correlated with TF antigen level and PCA of circulating monocytes. Adjusting for all patient characteristics, we confirmed these findings in multivariate regression analyses. In cultured THP-1 cells, ADMA transcriptionally upregulated both TF antigen expression and PCA in a concentration-dependent manner. The experiments using nuclear factor-kappaB (NF-kappaB) inhibitor and transient transfection with wild-type and mutated TF promotor constructs showed that the NF-kappaB is an important transcriptional regulator of ADMA-induced TF expression. Our results suggest that elevated plasma level of ADMA induces TF expression in monocytes via NF-kappaB-dependent pathway, which contributes to procoagulant phenotype of circulating monocytes in ACS.

Calcitonin gene-related peptide-mediated antihypertensive and anti-platelet effects by rutaecarpine in spontaneously hypertensive rats.

We have previously reported that Chinese traditional medicine rutaecarpine (Rut) produced a sustained hypotensive effect in phenol-induced and two-kidney, one-clip hypertensive rats. The aims of this study are to determine whether Rut could exert antihypertensive and anti-platelet effects in spontaneously hypertensive rats (SHR) and the underlying mechanisms. In vivo, SHR were given Rut and the blood pressure was monitored. Blood was collected for the measurements of calcitonin gene-related peptide (CGRP), tissue factor (TF) concentration and activity, and platelet aggregation, and the dorsal root ganglia were saved for examining CGRP expression. In vitro, the effects of Rut and CGRP on platelet aggregation were measured, and the effect of CGRP on platelet-derived TF release was also determined. Rut exerted a sustained hypotensive effect in SHR concomitantly with the increased synthesis and release of CGRP. The treatment of Rut also showed an inhibitory effect on platelet aggregation concomitantly with the decreased TF activity and TF antigen level in plasma. Study in vitro showed an inhibitory effect of Rut on platelet aggregation in the presence of thoracic aorta, which was abolished by capsazepine or CGRP(8-37), an antagonist of vanilloid receptor or CGRP receptor. Exogenous CGRP was able to inhibit both platelet aggregation and the release of platelet-derived TF, which were abolished by CGRP(8-37). The results suggest that Rut exerts both antihypertensive and anti-platelet effects through stimulating the synthesis and release of CGRP in SHR, and CGRP-mediated anti-platelet effect is related to inhibiting the release of platelet-derived TF.

Regulation by DDAH/ADMA pathway of lipopolysaccharide-induced tissue factor expression in endothelial cells.

Previous studies have shown the regulatory effect of nitric oxide (NO) on endotoxin-induced tissue factor (TF) in endothelial cells. Asymmetric dimethylarginine (ADMA), a major endogenous NO synthase (NOS) inhibitor, could inhibit NO production in vivo and in vitro. ADMA and its major hydrolase dimethylarginine dimethylaminohydrolase (DDAH) have recently been thought of as a novel regulatory system of endogenous NO production. The aim of the present study was to determine whether the DDAH/ADMA pathway is involved in the effect of lipopolysaccharide (LPS) on TF expression in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were treated with LPS (1 microg/ml) to induce TF expression. Exogenous ADMA significantly enhanced the increase in both TF mRNA level and activity induced by LPS, whereas L-arginine, the NOS substrate, markedly attenuated the LPS-induced TF increment. LPS markedly increased the level of ADMA in cultured medium and decreased DDAH activity in endothelial cells, and over-expression of DDAH2 could significantly suppress LPS-induced TF increment in endothelial cells. LPS could increase intracellular reactive oxygen species (ROS) production and activate nuclear factor-kappaB, which were enhanced by exogenous ADMA and attenuated by either L-arginine or overexpression of DDAH2. Therefore, our present results for the first time suggest that the DDAH/ADMA pathway can regulate LPS-induced TF expression via ROS-nuclear factor-kappaB-dependent pathway in endothelial cells.

Role of asymmetric dimethylarginine in homocysteine-induced apoptosis of vascular smooth muscle cells.

Homocysteine (Hcy) could induce apoptosis of vascular smooth muscle cells (VSMC). Asymmetric dimethylarginine (ADMA) has been thought as a novel risk factor for cardiovascular diseases. We hypothesized that ADMA mediates homocysteine-induced apoptosis of VSMC. In this experiment the level of ADMA in the medium measured by high-performance liquid chromatography (HPLC) was elevated when the apoptosis of T/G HA-VSMC was induced by Hcy which was detected by Hoechst33342 staining or flow cytometry (FCM) with Annecin V+Propidium Iodide (PI). Exogenous ADMA induced the apoptosis of VSMC. At the same time, ADMA elevated the level of intracellular reactive oxidative species (ROS) determined by fluorescent ROS detection kit. The activation of JNK and p38MAPK contributed to ADMA-induced apoptosis of VSMC. The present results suggest that endogenous ADMA is involved in apoptosis of VSMC induced by Hcy, and the effects of ADMA is related to elevation of intracellular ROS and activation of JNK/p38MAPK signaling pathways.

[CD34(+)/CD123(+) cell sorting from the patients with leukemia by Midi MACS method].

The aim of this study was to sort the CD34(+)/CD123(+) cells from the bone marrow cells of patients with acute myeloid leukemia (AML) by Midi MACS method. Firstly, the bone marrow mononuclear cells (BMMNC) were isolated from the patients with AML with Ficoll Paque, CD34(+) cells were then isolated by Midi MACS method followed by the isolation of CD34(+)/CD123(+) cells from the fraction of CD34(+) cells. The enrichment and recovery of CD34(+) and CD34(+)/CD123(+) cells were assayed by FACS technique. The results showed that the enrichment of CD34(+) cells was up to 98.73%, its average enrichment was 95.6%, and the recovery of CD34(+) was 84.6%, its average recovery was 51% after the first round sorting, by the second round sorting, the enrichment of CD34(+)/CD123(+) cells was up to 99.23%, its average enrichment was 83%. With regard to BMMNCs before sorting, the recovery of CD34(+)/CD123(+) was 34%. But, on the CD34(+) cells obtained by the first round sorting, its recovery was 56%. In conclusion, these results confirmed that the method of Midi MACS sorting can be applied to sort CD34(+)/CD123(+) cells from the bone marrow cells of AML patients, which give rise to the similar enrichment and recovery of the sorted cells with that of literature reported by the method of FACS.

[Expression of coagulation factor IX in human CD34 + hematopoietic stem cells by adeno-associated virus 2].

OBJECTIVE: To investigate the expression of human coagulation factor IX (hFIX) gene in human umbilical cord blood (CB) CD34+ cells which was transfected with recombinant adeno-associated virus 2 (rAAV-2). METHOD: The CD34+ cells were transfected with rAAV-2/hFIX and cultured for 21 days for inducing differentiation into myeloid, erythroid and megakaryocytes, respectively. The expression of hFIX was studied at mRNA, protein and biological activity levels. The cytotoxicity of rAAV-2 to CD34+ cells was evaluated by cell proliferation, cell vitality, CD antigen expressions and CFU yields. RESULTS: The hFIX mRNA was expressed in the cultured cells which was verified by RT-PCR and DNA sequencing. An elevated level of hFIX expression and biological activities were detected with a maximum amount of 14.10 ng/10(6) cell x 24 h. During the period of 21 day culture, the cell vitality, cell proliferation, CD antigen expression and CFU yields between the transfected and un-transfected groups had no difference(P > 0.05). CONCLUSION: The human CB CD34+ cells are able to produce functional hFIX after transduction by rAAV-2/hFIX. The cell proliferation and differentiation capacities of the host CD34+ cells were not affected by rAAV-2.