[Show abstract][Hide abstract] ABSTRACT: Aplastic anemia (AA) is generally considered as an immune-mediated bone marrow failure syndrome with defective hematopoietic stem cells (HSCs) and marrow microenvironment. Previous studies have demonstrated the defective HSCs and aberrant T cellular-immunity in AA using a microarray approach. However, little is known about the overall specialty of bone marrow mesenchymal stem cells (BM-MSCs). In the present study, we comprehensively compared the biological features and gene expression profile of BM-MSCs between AA patients and healthy volunteers. In comparison with healthy controls, BM-MSCs from AA patients showed aberrant morphology, decreased proliferation and clonogenic potential and increased apoptosis. BM-MSCs from AA patients were susceptible to be induced to differentiate into adipocytes but more difficult to differentiate into osteoblasts. Consistent with abnormal biological features, a large number of genes implicated in cell cycle, cell division, proliferation, chemotaxis and hematopoietic cell lineage showed markedly decreased expression in BM-MSCs from AA patients. Conversely, more related genes with apoptosis, adipogenesis and immune response showed increased expression in BM-MSCs from AA patients. The gene expression profile of BM-MSCs further confirmed the abnormal biological properties and provided significant evidence for the possible mechanism of the destruction of the bone marrow microenvironment in AA.
PLoS ONE 01/2012; 7(11):e47764. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Genome-wide hypomethylation has been confirmed in patients with primary immune thrombocytopenia (ITP). Proteins containing methylcytosine-binding domain (MBD) are involved in promoter methylation as transcriptional repressors and promote the gene-silencing effect of DNA methylation. The purpose of this study was to investigate the methylation pattern of T cells and the relationship between genomic methylation and the expression of MBD2 and MBD4 in ITP patients. DNA deoxymethylcytosine content of CD4(+) cells from peripheral blood mononuclear cells was measured by enzyme-linked immunoassay. Real-time polymerase chain reaction was performed to quantify the transcription levels of MBD2 and MBD4 in peripheral blood mononuclear cells and CD4(+) cells. DNA dmC content in CD4(+) cells of ITP patients was significantly lower than in the controls (p = 0.001). The mRNA level of MBD2 and MBD4 in CD4(+) cells of ITP patients was statistically lower than those of the controls (p < 0.001). Positive correlations between methylation indexes and expression of each enzyme were observed in the control group (r(2) = 0.718, p = 0.004 for MBD2; r(2) = 0.608, p = 0.015 for MBD4). However, inverse correlations were found in ITP patients (r(2) = 0.604, p = 0.008 for MBD2; r(2) = 0.498, p = 0.027 for MBD4). Our results indicate that decreased expression of MBD2 and MBD4 might involve in the pathogenesis of ITP.
Human immunology 03/2011; 72(6):486-91. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was aimed to investigate whether mesenchymal stem cells (MSC) can be isolated from bone marrow filters which have always been discarded. The bone marrow (BM) particles from BM filters of 2 healthy donors were cultivated by primary explant culture. After expansion, the number of MSC was counted and their immunophenotype and differentiation potential were detected. The results indicated that many MSC were found in bone marrow particles from filters, and nearly 10(7) MSC were obtained at 3 passages of expansion. They not only possessed the characteristics of morphology and immunophenotype of MSC, but also could differentiate into osteoblasts, chondrocytes and adipocytes. In conclusion, a large amount of MSC can be obtained from BM filters if the BM particles were cultivated by primary explant culture.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 03/2011; 19(2):459-63.
[Show abstract][Hide abstract] ABSTRACT: This study was aimed to investigate the enhancement of all-trans retinoic acid-induced HL-60 leukemia cell differentiation by human umbilical cord mesenchymal stem cells (hucMSC). The HL-60 cells were divided into 4 groups: control group (HL-60 cells treated without ATRA), hucMSC group (HL-60 cells co-cultured with hucMSCs), ATRA group (HL-60 cells treated with ATRA) and ATRA + hucMSC group (HL-60 cells treated with ATRA and co-cultured with hucMSCs). The proliferations of control group and hucMSC group were compared by Cell Counting Kit-8 (CCK8). The morphology of HL-60 cells and NBT positive rate in 4 groups were observed and compared by means of microscopy, the c-myc expression of HL-60 cells in different groups was evaluated by real-time PCR, and the CD11b expression on HL-60 cells in different groups were detected by flow cytometry. The results showed that in the co-culturing system, hucMSCs could inhibit the proliferation of HL-60 (hucMSC:HL-60 is 1:1, 48 hours p < 0.05, 72 hours p < 0.01; hucMSC:HL-60 is 1:5, 72 hours p < 0.05). In condition of stimulation with 2 micromol/L ATRA, the neutrophil like HL-60 cells and NBT positive rate in ATRA + hucMSC group were higher than those in ATRA group (p < 0.05). The c-myc expression of HL-60 cells in ATRA + hucMSC group was lower than that in ATRA group (p < 0.05). Furthermore, HL-60 cells in ATRA + hucMSC group had stronger CD11b expression than ATRA group (48 hours p < 0.05, 72 hours p < 0.01). It is concluded that hucMSC not only can inhibit the proliferation of HL-60 cells, but also can enhance the differentiation effect of HL-60 cells induced by ATRA.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 08/2010; 18(4):877-81.
[Show abstract][Hide abstract] ABSTRACT: To investigate the biological function of hepatocyte-like cells derived from mesenchymal stem cells that isolated from human umbilical cord UC-MSCs in vitro, and to detect the changes in the immunogenicity of the differentiated hepatocyte-like cells (DHC).
Transdifferentiation of UC-MSCs into hepatic lineage in vitro was induced in modified two-step induction medium. The expressions of hepatic specific markers were detected by RT-PCR analysis and immunofluorescence staining at different time points after induction. The levels of albumin and urea in the supernatants of cultures were measured by enzyme-linked immunosorbent assay. Furthermore, the immunosuppressive property of DHC was detected by one-way mixed lymphocyte culture.
The mRNA and proteins of alpha fetoprotein (AFP), albumin (ALB),and cytokeratin-19 (CK-19) were expressed in naive UC-MSCs at low levels. DHC highly expressed hepatic markers AFP, ALB, CK-19, and tryptophan 2, 3-dioxygenase 14 and 28 days after hepatic differentiation and were accompanied by an increased production of ALB and urea in supernatant in a time-dependent manner. DHC did not express human leukocyte antigen DR antigen and significantly decreased the lymphocyte proliferation.
UC-MSCs are able to differentiate into functional hepatocyte-like cells in vitro, while the immunogenicity of DHC remains low.
Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae 04/2010; 32(2):190-4.
[Show abstract][Hide abstract] ABSTRACT: The present study was aimed to investigate the pathways, by which IL-27 regulates the expression of adherent molecule Mac-1, chemotactic factor receptor fMLP-R and pro-inflammatory cytokine IL-1beta in human neutrophils. Highly purified human neutrophils were isolated from peripheral blood using Ficoll-Hypaque gradients centrifugation and erythrocyte lysis. The mRNA expression of IL-27 receptor components (WSX-1/TCCR and gp130) in human neutrophils was detected by reverse transcription polymerase chain reaction (RT-PCR). After incubation with IL-27 and specific inhibitors (p38 MAPK inhibitor SB203580, PI3K inhibitor LY294002 and ERK inhibitor U0126), the mRNA levels of fMLP-R and IL-1beta were determined by real time RT-PCR, and the adherent molecule Mac-1 expression in human neutrophils was determined by flow cytometry. The IL-1beta level in culture supernatant of human neutrophils was assayed by radioimmunoassay. The results showed that IL-27 receptor components (WSX-1/TCCR and gp130) were constitutively expressed in human neutrophils. IL-27 down-regulated Mac-1 expression in human neutrophils (p<0.05). After incubation with specific inhibitors, SB203580, not LY294002 and U0126, inhibited the down-regulation of Mac-1 expression by IL-27. However, IL-27 up-regulated the mRNA expression of fMLP-R and IL-1beta, and increased the release of IL-1beta (p<0.05). Interestingly, LY294002, not SB203580 and U0126, inhibited the up-regulation of fMLP-R and IL-1beta by IL-27. It is concluded that the IL-27 may regulate the expression of Mac-1, fMLP-R and IL-1beta in human neutrophils through p38 MAPK and PI3K signal pathways.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 04/2010; 18(2):391-5.
[Show abstract][Hide abstract] ABSTRACT: The acceleration of capillarization and venularization of hepatic sinusoids after cell therapy would not be beneficial to restoration after liver disease. The goal was to observe the effects of umbilical cord (UC)-derived mesenchymal stromal cells (MSC) on liver microcirculation and their therapeutic potential in liver fibrosis.
Human UC MSC labeled with or without CM-DIL were transplanted into NOD/SCID mice with carbon tetrachloride (CCl4)-induced chronic liver fibrosis models. Because of the high autofluorescence on the injured liver sections, we used immunohistochemistry, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR), but not immunofluorescence, in order to avoid false images under a confocal fluorescence microscope.
Human-specific alpha-fetoprotein and albumin mRNA and proteins were detected in CCl4-treated mouse livers receiving human UC MSC transplants. We only observed the gene expression of human-specific endothelial-like cells markers CD31 and KDR by RT-PCR, but not protein expression by immunohistochemistry, in UC MSC-transplanted mouse livers. Vascular endothelial growth factor (VEGF) expression in injured livers 4 weeks after UC MSC transplantation was higher than in normal livers. However, UC MSC injection did not increase significantly the vascular density labeled by CD31 and (vWF) in the injured livers of UC MSC-transplanted mice compared with non-transplanted mice after CCl4 treatment. In addition, liver function was partly improved after UC MSC transplantation.
Human UC MSC can differentiate into hepatocyte-like cells but do not accelerate the capillarization and venularization of hepatic sinusoids, finally leading to the partial improvement of liver function in mice with CCl4-mediated chronic liver fibrosis.
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) have been implicated in antitumor therapy for hematopoietic and non-hematopoietic tumors. Cell-contact and soluble factors are demonstrated to play a role in the growth inhibition of tumor cells mediated by MSCs in vitro, while there is little clue about signaling pathways involved in the process. P38 MAPK has been implicated as a suppressor of cell proliferation and tumorigenesis. We here investigate whether p38 MAPK is involved in MSC-induced growth inhibition of leukemic tumor cells. Methods: We characterized the effect of human umbilical cord mesenchymal stem cells (UC-MSCs) on proliferation, cell cycle and phosphorylation pattern of p38 MAPK in HL60 and K562 cells. SB203580, a specific inhibitor of p38 MAPK, or p38 MAPK-small interfering RNA (siRNA), were used to identify the role of p38 in growth suppression by UC-MSCs. We also investigated the expression of cell cycle regulators.
Treatment with UC-MSCs led to potent proliferation-inhibition of HL60 and K562 cells without inducing apoptosis. Growth inhibition by UC-MSCs was due to G0/G1 arrest. UC-MSCs increased phosphorylation of p38 MAPK in HL60 and K562 cells. Pharmacological inhibition or genetic silencing (through siRNA) of p38 MAPK partially abrogated the proliferation-suppression and cell cycle arrest caused by UC-MSCs. UC-MSCs also modulated the expression of cell cycle regulatory proteins in HL60 and K562 cells while SB203580 reversed the effect.
Taken together, our findings indicate that p38 MAPK is critical for the growth inhibitory effect of UC-MSCs on leukemic tumor cells.
Cellular Physiology and Biochemistry 01/2010; 26(6):799-808. · 3.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The regulation of growth and apoptosis in K562 cells by human bone marrow mesenchymal stem cells (MSCs) from leukemia patients was investigated.
K562 cells were cocultured with leukemic MSCs under serum deprivation. Cell Counting Kit-8 (CCK-8), PI staining, Annexin V/PI binding and FACS assays were used to investigate cell proliferation, cell cycle status, and apoptosis of K562 cells cultures in the presence or absence of 10% serum. Western blotting was used to determine the levels of Akt, phosphorylated Akt (p-Akt), the BCL-2 family member Bad, and phosphorylated Bad (p-Bad) proteins in K562 cells after coculturing with MSCs. The effects of LY294002 (a specific inhibitor of PI3K) on protein expression were also determined.
K562 cell proliferation was inhibited by coculture with MSCs and the dominant cell cycle was the G0-G1 phase. The proportion of apoptotic K562 cells was decreased and the levels of p-Akt and p-Bad were upregulated after exposing K562 cells to MSCs. However, when LY294002 was used, p-Akt and p-Bad proteins inK562 cells showed a significant reduction, while no distinct variation was seen in the nonphosphorylated Akt and Bad protein levels.
Leukemic MSCs can inhibit K562 cell expansion and modulate the cell cycle to a state of relative quiescence. This allows the K562 cells to endure adverse conditions such as serum starvation. The PI3K-Akt-Bad signaling pathway may be involved in this antiapoptotic process via phosphorylation of the Akt and Bad proteins. Blocking MSC-induced transduction of the PI3K-Akt-Bad pathway may be a potential strategy for a targeted therapy to combat leukemia.
Journal of Experimental & Clinical Cancer Research 11/2009; 28:141. · 3.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The ATP-binding cassette efflux transporter, ABCG2, is widely expressed in a variety of normal tissues, stem cells, as well as cancer cells. Existing data suggest that ABCG2 plays an important role in the maintenance of the stem cell phenotype and multidrug resistance of cancer cells. However, the potential role of ABCG2 in other cellular processes remains speculative and poorly understood. Here, we demonstrated that ABCG2 is involved in the proliferation of cancer cells. We used RNA interference approach to efficiently and specifically down-regulate ABCG2 protein levels in MCF-7/MX and A549 cells. We showed that knockdown of ABCG2 significantly inhibited the proliferation of these cells. Suppression of ABCG2 reduced the percentage of cells in the S phase of the cell cycle and enhanced G0/G1 accumulation. The G0/G1 growth arrest was associated with down-regulation of cyclin D3 and up-regulation of p21. Furthermore, blocking of ABCG2 function by chemical inhibitor fumitremorgin C also inhibited cell proliferation via the prolonged G0/G1 interval. Taken together, these findings suggest that ABCG2 correlates with cell cycle progression, highlighting a novel function of ABCG2 in cancer cell proliferation.
International Journal of Cancer 08/2009; 126(4):841-51. · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was aimed to examine the expression and promoter CpG island methylation of homeobox B4 (HOXB4) gene in CD34(+) cells from cord blood and peripheral blood mononuclear cells (PBMNCs) from health adult, and to investigate the expression level of HOXB4 in these two cells and its relationship with the promoter methylation. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to examine the expression of HOXB4 in CD34(+) cells and PBMNCs, and bisulfite sequencing technique was used to detect the methylation status of the promoter CpG sites of HOXB4 gene in CD34(+) cells and PBMNCs. The results indicated that highly expressed HOXB4 and unmethylation of HOXB4 promoter CpG island occurred in CD34(+) cells. However, loss of HOXB4 expression and the methylated CpG island of HOXB4 were observed in PBMNCs, and the methylated C residue was positioned at -129 bp in the upstream of ATG. It is concluded that the methylation status of HOXB4 gene promoter may be one negative regulatory mechanism for HOXB4 gene expression. The unmethylation of CpG island in the promoter region of HOXB4 gene may be correlated with the high expression of HOXB4 gene in CD34(+) cells, while the promoter methylation of HOXB4 gene may be associated with HOXB4 gene silencing in PBMNCs. The preliminary identification of HOXB4 promoter methylation site would provide a basis for further study and a novel approach to expand hematopoietic progenitor cells.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 07/2009; 17(3):674-8.
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to investigate whether lovastatin restores the survival and function of endothelial progenitor cells (EPCs) damaged by oxLDL.
EPCs were preincubated with different concentrations of lovastatin (2, 10, and 50 micromol/L) with or without the Akt inhibitor triciribine for 24 h and were then exposed to 50 microg/mL oxLDL for 48 h. The survival of EPCs, as well as the cellular migration, adhesion, and tube formation of these cells, was examined. To explore the mechanisms of lovastatin's effects on EPCs, the levels of phosphorylated Akt and eNOS and of total eNOS protein and mRNA were assayed.
Incubation of EPCs with oxLDL resulted in significant apoptosis and impaired cellular migration, adhesion and tube structure formation. The detrimental effects of oxLDL on EPC survival and function were attenuated by pretreatment of EPCs with lovastatin. However, when EPCs were pretreated with lovastatin and triciribine at the same time, the beneficial effects of lovastatin were abolished by triciribine. Furthermore, oxLDL caused a significant downregulation of eNOS mRNA and protein expression, as well as a suppression of Akt and eNOS phosphorylation. However, the effects of oxLDL on Akt/eNOS activity and eNOS expression were reversed by lovastatin.
Lovastatin reverses the survival and function of EPCs by regulating the Akt/eNOS signaling pathway and the gene transcription of eNOS.
[Show abstract][Hide abstract] ABSTRACT: Bmi-1 is a transcriptional repressor, which belongs to the polycomb group family. It has been demon- started that over-expression of Bmi-1 occurs in a variety of cancers, including several types of leukemia. Bmi-1 gene plays a key role in regulation of self-renewal in normal and leukemic stem cells. Acute myeloid leukemic cells lacking Bmi-1 undergo proliferation arrest and show signs of differentiation and apoptosis, which leads to the proposal of Bmi-1 as a potential target for therapeutic intervention in leukemia. The purpose of this study was to investigate the effect of short hairpin RNA (shRNA) targeting Bmi-1 on functions of K562 cell line. The shRNA eukaryotic expression vector targeting Bmi-1 was constructed and transfected into K562 cells through lipofectamine 2000. The mRNA and protein levels of Bmi-1 were detected by PCR and Western blot respectively. The proliferation of K562 after Bmi-1 silencing was measured by using MTT assay and clone formation assay. The cell cycle was detected by flow cytometry. The results indicated that among the four shRNA designed, there was a shRNA which efficiently interfered with the expression of Bmi-1. The results of PCR and Western blot validated that the Bmi-1 gene of K562 cells transfected with such a Bmi-1 shRNA was suppressed successfully. Although levels of Bmi-1 mRNA and protein were significantly reduced, delivery of this siRNAs had no effect on cell viability or growth. Flow cytometry analysis suggested that Bmi-1 inhibition did not affect the cell cycle. It is concluded that the suppression of Bmi-1 expression is not able to reduce proliferation of K562 cells, suggesting existence of some other parallel signaling pathways, which are fundamental for leukemic transformation and are independent of Bmi-1 over-expression. Bmi-1 over-expression may play a secondary role in chronic myeloid leukemia transformation.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 05/2009; 17(2):266-70.
[Show abstract][Hide abstract] ABSTRACT: PI3K signaling pathway plays a significant role in embryonic stem cells (ES cells) self-renewal. Overexpression of Nanog maintains mouse ES cells pluripotency independent of leukemia inhibitory factor (LIF). However, little is known about the effect of PI3K signaling pathway on ES cells with Nanog overexpression. Our experiments aimed to explore the relationship between PI3K signaling pathway and Nanog expression in ES cells. We observed the effect of LY294002, a specific inhibitor of PI3K pathway, on wild-type J1 cells and Nanog overexpressing (Ex-Nanog) J1 cells in the presence or absence of LIF. With LY294002 treatment, both of them lost their ES features even in the presence of LIF. But the differentiation induced by LY294002 on Ex-Nanog J1 cells was slighter lower than that on wild-type J1 cells. These results indicate that inhibition of PI3K pathway induces mouse ES cells differentiation. Exogenous Nanog sustains mouse ES cells pluripotency independent of LIF, and alleviates the differentiation induced by LY294002. But it is insufficient to totally reverse the differentiation.
Journal of Cellular Biochemistry 03/2009; 106(6):1041-7. · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to investigate the expression of human Factor IX (hFIX) in retrovirus-transfected human umbilical cord tissue derived mesenchymal stem cells (hUCT-MSCs). The pLEGFP-N1-hFIX vector was generated by cloning a 3.0 kb Bgl II-BamH I fragment from the pIRES2-EGFP-hFIX plasmid containing the hFIX cDNA and part of intron 1 of hFIX in pLEGFP-N1 vector. The retroviral supernatants were produced from the Phoenix packaging cell line and then infected the hUCT-MSCs. After selection with G418 for 10 day, the expression of FIX was detected by ELISA and Western blot. The biological activity of FIX was determined by the clotting assay employing human Factor IX-deficient plasma. The results showed that compared with the activity of pooled human normal plasma (100%), transduced cells produced biologically active hFIX with 100-130% activity in two-day culture supernatant and expressed hFIX at levels of 2.68 +/- 0.36 microg/10(6) cells/24 hours after G418 selection for 10 days. The secretion of hFIX into culture supernatant was also confirmed by Western blot analysis. It is concluded that genetically modified hUCT-MSCs can express biologically active hFIX and thus serve as an efficient drug delivery vehicle carrying hFIX used as a way of somatic gene therapy for hemophilia B.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 03/2009; 17(1):184-7.
[Show abstract][Hide abstract] ABSTRACT: BAFF (B-cell activating factor belonging to the TNF family) is an essential component of B-cell homeostasis, and is required for the normal survival and development of B cells. To further explore the role of this cytokine in the pathogenesis of idiopathic thrombocytopenic purpura (ITP), BAFF/BAFF-R (one of receptors of BAFF) expression levels were determined and the correlation between the clinical parameters and the BAFF expression levels was analyzed. A total of 57 patients with ITP were enrolled and 25 age and sex-matched healthy volunteers served as controls. Serum was obtained from 41 patients with ITP and 22 healthy volunteers and was analyzed with a commercial human soluble BAFF (sBAFF) ELISA kit. BAFF and BAFF-R mRNA expression of peripheral blood (PB) (n = 42) and splenocytes (SP) (n = 8) mononuclear cells (MNC) were determined by real-time quantitative PCR. The SPMNC of normal controls came from three hereditary spherocytosis patients who underwent splenectomy. The untreated patients with ITP had higher serum BAFF levels (Median 1430 pg/ml, Range: 534-5787 pg/ml) than those of normal controls (Median 1120 pg/ml, Range: 640-2376 pg/ml, p = 0.006) and treated ITP group (Median 662 pg/ml, Range 267-1265 pg/ml, p = 0.000). On the other hand, serum BAFF levels of treated patients with ITP were lower than those of normal controls (p = 0.001). There was a weak correlation (the Pearson correlation coefficient is - 0.242) between platelet count and BAFF (p = 0.064). However, BAFF levels did not correlate with platelet associated immunoglobulin or immunoglobulin levels. Moreover, the serum BAFF levels were not statistically different between acute and chronic ITP (p = 0.841). PBMNC of ITP had higher BAFF but not BAFF-R mRNA expression than that of normal controls. BAFF mRNA expression of SPMNC had a positive correlation with BAFF-R in ITP patients but not in PBMNC of normal controls and untreated ITP patients. The BAFF-R mRNA expression of SPMNC was shown to be 15.29 times higher than that of PBMNC in ITP. BAFF might contribute to autoimmunity and disease development in ITP. However, BAFF serum level must be carefully considered as a surrogate marker of disease activity in ITP.
[Show abstract][Hide abstract] ABSTRACT: DNA methylation is known to play an important role in gene transcription and alterations of methylation contribute to the development of certain disorders such as cancer and immunodeficiency. Recent years have found an increasing interest in the role of epigenetic modifications in the etiology of human autoimmune diseases, such as systemic lupus erythromatosus (SLE) and rheumatoid arthritis (RA). DNA methyltransferases (DNMTs) are involved in the epigenetic control of DNA methylation processes. S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), as the substrate and product of essential cellular methyltransferase reactions, have important indicator action of cellular methylation status. The aim of this study is to explore if DNA methylation plays a role in the pathogenesis of idiopathic thrombocytopenic purpura (ITP).
DNMT1, DNMT3A, and DNMT3B mRNA expression in peripheral blood mononuclear cells (PBMCs) of adult ITP patients were analyzed by real-time quantitative polymerase chain reaction. Plasma SAM and SAH levels were assayed with reversed-phase high performance liquid chromatography (HPLC).
DNMT3A and DNMT3B mRNA expressions were significantly lower in ITP patients than in healthy controls (p < 0.001), while DNMT1 mRNA expression was not significantly different between the two groups (p = 0.774). Plasma SAH concentration was significantly elevated in ITP patients than in healthy controls (p < 0.05), while the plasma SAM and SAM/SAH were not significantly different between the two groups (p = 0.133, p = 0.624 respectively).
Our observations suggest that aberrant DNA methylation status reflected by increased plasma SAH concentration and decreased mRNA expression levels of DNMT3A and 3B are possibly involved in the pathogenesis of ITP although the precise mechanisms need further study.
Journal of Clinical Immunology 10/2008; 28(5):432-9. · 3.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epigenetic changes in gene expression, including DNA methylation and histone modifications, might contribute to autoimmunity. DNA methylation is mediated by a family of DNA methyltransferases. Polymorphisms of the DNA methyltransferase 3B (DNMT3B) gene may influence DNMT3B activity on DNA methylation, thereby modulating the susceptibility to some diseases. The purpose of this study was to investigate the association between the single nucleotide polymorphism (SNP) in promoter of the DNMT3B gene and the risk for development of idiopathic thrombocytopenic purpura (ITP).
In this hospital-based case-control study, the DNMT3B SNP was genotyped in 201 patients with ITP and 136 healthy controls by polymerase chain reaction-restriction fragment length polymorphism.
The C/C genotype was not detected in both the patients with ITP and the controls. In the controls, the frequencies of T/T and C/T genotypes and T and C alleles were 97.8%, 2.2%, 98.9%, and 1.1%, respectively. There was no significant difference in genotype and allele distribution between the patients with ITP and the controls (P = 0.745 and 0.747, respectively). No significant difference was observed in genotype and allele distribution between the two groups when stratified by the age. The similar results were shown among the four groups of patients with ITP: acute childhood, chronic childhood, acute adult, and chronic adult.
This polymorphism was distributed similarly between the patients with ITP and the controls. It demonstrated that it may not be used as a stratification marker to predict the susceptibility to ITP, at least in the population of North China.
Journal of Clinical Immunology 05/2008; 28(5):399-404. · 3.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Interleukin-27 (IL-27) is an IL-12-related cytokine that can promote both anti- and pro-inflammatory immune responses. In this study, we used the promonocytic cell line THP-1, an established model for monocytes to investigate if the immunoregulatory role of IL-27 is in part due to effects on major histocompatibility complex (MHC) Ag presentation. We find that IL-27 induces mRNA and surface expression of class II MHC in THP-1 cells. IL-27 also increases class I MHC heavy chain, beta2m, and TAP-1 transcripts, leading to an increased surface expression of class I MHC. In addition, IL-27 enhances expression of costimulatory molecules CD80 and CD86 and adhesion molecule CD54. Expression of the class II transactivator (CIITA) isoforms III and IV, but not I, transcripts increases in response to IL-27. Our data suggest that the pro-inflammatory role of IL-27 is mediated in part through increased expression of key molecules involved in the class II and class I MHC pathways.
Biochemical and Biophysical Research Communications 04/2008; 367(3):553-9. · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hemangiopoietin (HAPO) is a novel human growth factor acting on the primitive cells of both hematopoietic and endothelial cell lineages. Our previous study has shown that HAPO exerts a proliferative effect on endothelial cells. However, the mechanism of this action remains unclear. Thus, we studied the signal transduction pathway whereby HAPO promotes cell proliferation in human umbilical vein endothelial cells (HUVECs). In this study, recombinant human HAPO (rhHAPO) stimulated the proliferation of HUVECs in a dose-dependent manner. The transient phosphorylation of Akt occurred after addition of rhHAPO to HUVECs. LY294002, a specific inhibitor of PI-3K, significantly inhibited Akt phosphorylation and completely abrogated HAPO-stimulated proliferation of HUVECs. rhHAPO enhanced the expression of cyclin D1, where as LY294002 inhibited the up-regulation of cyclin D1. Moreover, rhHAPO is able to selectively enhance the mitogenic activity of VEGF for vascular endothelial cells. Overall, these findings demonstrate that HAPO induces endothelial cell proliferation through the PI-3K/Akt pathway.
Cellular Physiology and Biochemistry 02/2008; 22(1-4):307-14. · 3.42 Impact Factor