Weiting Du

Human umbilical cord mesenchymal stem cells ameliorate mice trinitrobenzene sulfonic acid (TNBS)-induced colitis.

Mesenchymal stem cells (MSCs), which are poorly immunogenic and have potent immunosuppressive activities, have emerged as a promising candidate for cellular therapeutics for the treatment of disorders caused by abnormal immune responses. In this study we investigated whether human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) could ameliorate colitis in a trinitrobenzene sulfonic acid (TNBS)-induced colitis model. TNBS-treated colitic mice were infused with hUC-MSCs or vehicle control. The mice were sacrificed on day 1, 3, and 5 after infusion, and their clinical and pathological conditions were evaluated by body weight, colon length, and histological analysis. The expression levels of proinflammatory cytokine proteins in colon were examined by ELISA. The homing of hUC-MSCs was studied by live in vivo imaging and immunofluorescent microscopy. hUC-MSCs were found to migrate to the inflamed colon and effectively treated the colitic mice with improved clinical and pathological signs. The levels of IL-17 and IL-23 as well as IFN-γ and IL-6 were significantly lower in the colon tissues of the hUC-MSC-treated mice in comparison with the vehicle-treated mice. Coculture experiments showed that hUC-MSCs not only could inhibit IFN-γ expression but also significantly inhibit IL-17 production by lamina propria mononuclear cells (LPMCs) or splenocytes of the colitic mice or by those isolated from normal animals and stimulated with IL-23. Systemically infused hUC-MSCs could home to the inflamed colon and effectively ameliorate colitis. In addition to the known suppressive effects on Th1-type immune responses, hUC-MSC-mediated modulation of IL-23/IL-17 regulated inflammatory reactions also plays an important role in the amelioration of colitis.

MicroRNA and leukemia: Tiny molecule, great function

MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their targeted messenger RNAs (mRNAs). It is known that aberrant microRNA expression can play a vital role in the pathology of leukemia, thus microRNAs have rapidly emerged as potential targets for therapeutics. This review focuses on recent researches on the important roles of microRNAs in the pathogenesis of leukemia, including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL).

Fetal BM-derived mesenchymal stem cells promote the expansion of human Th17 cells, but inhibit the production of Th1 cells

Th type 17 (Th17) cells have been identified as a proinflammatory T‐cell subset. Here, we investigated the regulation of human Th17 cells by fetal BM‐derived mesenchymal stem cells (FBM‐MSC). We cocultured FBM‐MSC with human PBMC or CD4+ T cells from healthy donors. FBM‐MSC significantly suppressed the proliferation of CD4+ T cells stimulated by PHA and recombinant IL‐2. Significantly higher levels of IL‐17 were observed in FBM‐MSC cocultured with either PBMC or CD4+ T cells than that in PBMC cultured alone or CD4+ T cells cultured alone. Flow cytometry analysis showed that the percentage of Th17 cells in coculture of FBM‐MSC and CD4+ T cells was significantly higher than that in CD4+ T‐cell cultured alone. FBM‐MSC did not express IL‐17 protein. Consistent with the augmentation of Th17 cells, significantly higher levels of IL‐6 and IL‐1 were observed in coculture of FBM‐MSC and CD4+ T cells than that in CD4+ T‐cell culture, while the levels of IL‐23 were similar between FBM‐MSC + PBMC coculture and PBMC alone, or FBM‐MSC + CD4+ T‐cell and CD4+ T‐cell alone. The presence of FBM‐MSC decreased the percentage of Th1 cells, but minimally affected the expansion of CD4+CD25+ T cells. In conclusion, our data demonstrate for the first time that FBM‐MSC promote the expansion of Th17 cells and decrease IFN‐γ‐producing Th1 cells. These data suggest that IL‐6 and IL‐1, instead of IL‐23, may be partly involved in the expansion of Th17 cells.

Neural ganglioside GD2 identifies a subpopulation of mesenchymal stem cells in umbilical cord.

In contrast to hematopoietic stem cells, there is still a lack of definitive cell markers for specific isolation and identification of mesenchymal stem cells (MSCs). Thus a homogenous population of MSCs is only obtained after several passages, when multilineage potential or other distinctive features of very early progenitors may be already somewhat compromised. Recently a novel surface marker the neural ganglioside GD2 has been reported to distinguish MSCs from all other cells within marrow. Here, we found that MSCs derived from umbilical cord (UC-MSCs) also expressed this marker at early-passages. More importantly, UC-MSCs were the only cells within umbilical cord expressing this marker. Compared to unsorted cells, GD2+-sorted cells not only possessed much higher clonogenicity and proliferation capacity but also had significantly stronger multi-differentiation potentials. Flow cytometric analysis revealed that GD2+-sorted cells showed increased expression of SSEA-4, Oct-4, Sox-2 and Nanog, the typical markers expressed in embryonic stem cells, in comparison to unsorted or GD2-negative MSCs. Take together, our data demonstrate that the cells selected by GD2 are a subpopulation of MSCs with feature of primitive precursor cells and provide evidence that GD2 can be a cell surface marker suitable for the isolation and purification of UC-MSCs in early-passage culture.

BAFF and BAFF-R of peripheral blood and spleen mononuclear cells in idiopathic thrombocytopenic purpura.

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.

Th1 (CXCL10) and Th2 (CCL2) chemokine expression in patients with immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired organ-specific autoimmune disease with a polarization of T(h)1. Both the T(h)1 chemokine CXCL10 and T(h)2 chemokine CCL2 have been studied in several autoimmune diseases, but the status of these chemokines in ITP is still unknown. The aims of this study were to determine the expression of CXCL10 and CCL2 and their receptors, CXCR3 and CCR2, in ITP patients, and to conduct a preliminary study of the pathogenic roles of these factors in ITP. Plasma samples from 49 patients with ITP and 24 normal healthy subjects were assayed for CXCL10 and CCL2 plasma concentration by enzyme-linked immunosorbent assay. Real-time quantitative polymerase chain reaction was performed to determine the mRNA expression of these chemokines and their receptors in the PBMNC of 24 normal controls and 28 active ITP patients as well as splenocytes of nine ITP patients. The CXCL10 levels in the plasma samples from patients with active ITP were significantly higher than those from healthy controls (p = 0.007) and decreased to normal levels in patients with remission ITP. In contrast, CCL2 levels were similar in patients with active disease, patients in remission, and control subjects. PBMNC of patients with active disease expressed more CXCL10 mRNA (p = 0.031) but less CCR2 mRNA (p = 0.005). Lower peripheral platelet count correlated with higher CXCL10 levels and CXCL10/CCL2 ratios. Our study demonstrated that plasma levels of CXCL10 and CXC10/CCL2 ratio were higher in patients with active ITP than in healthy donors, and had an association with platelet counts of the patients. CXCL10 might be a pathogenic factor of this disorder.

Factor VIII gene mutations profile in 148 Chinese hemophilia A subjects

Background:  Hemophilia A (HA) is a common X‐linked recessive bleeding disease caused by mutations in FVIII gene. The identification of mutation in HA subjects can lead to more accurate diagnosis and contribute to the genetic counseling/prenatal diagnosis.

Association of cytotoxic T-lymphocyte antigen 4 gene polymorphisms with idiopathic thrombocytopenic purpura in a Chinese population

Idiopathic thrombocytopenic purpura (ITP) is an acquired organ-specific autoimmune hemorrhagic disease with many immune dysfunctions. Cytotoxic T lymphocyte antigen 4 (CTLA-4) is a T-lymphocyte surface molecule that can down modulate and terminate immune responses. Recently, several studies have confirmed that some polymorphisms of this gene can influence its expression level, therefore speculating that they might be associated with autoimmune diseases. In order to investigate the role of the CTLA-4 gene in ITP, we investigated -318 and CT60 polymorphisms of the CTLA-4 gene in 186 ITP patients and 162 healthy controls through polymerase chain reaction (PCR)–restriction fragment length polymorphism. No significant differences were revealed in genotypes and allele distributions between the patients with ITP and the controls in both sites. Similar results were observed between the two groups when stratified by first onset age and disease course including acute childhood, chronic childhood, acute adult, and chronic adult. In the conclusion, these two single-nucleotide polymorphisms in CTLA-4 are not associated with susceptibility to ITP in a Chinese population.

Single Nucleotide Polymorphism in DNMT3B Promoter and the Risk for Idiopathic Thrombocytopenic Purpura in Chinese Population

ObjectiveEpigenetic 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).MethodsIn 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.ResultsThe 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.ConclusionThis 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.

The expression of IFN-γ, IL-4, Foxp3 and perforin genes are not correlated with DNA methylation status in patients with immune thrombocytopenic purpura

We investigated the relationship between the expression of IFN-γ, IL-4, Foxp3 and perforin gene and the methylation status of their promoters in immune thrombocytopenic purpura (ITP) patients. Gene expression and DNA methylation were determined by quantitative PCR and bisulfite genomic sequencing, respectively. The expression of IFN-γ was higher, while the expression of IL-4 was notably lower in ITP patients when compared with the controls. Most importantly, the Th1/Th2 (IFN-γ/IL-4) was remarkably higher in ITP patients, showing that the ITP patients were mainly in the Th1 polarization response. Although the methylation rate of CpGs located at −409 of perforin was higher (p = 0.0376) and that of IFN-γ were relatively higher (p = 0.0582) in ITP, we did not find the negative correlation between the expression of those genes and the methylation of their promoters.