Biomedical subjects

Xueguang Zhang

Publications and source records attributed to Xueguang Zhang.

12 recordsLinked to original sources

PubMed2007

TIMP-1 transgenic mice recover from diabetes induced by multiple low-dose streptozotocin.

Type 1 diabetes results from autoimmune destruction of the insulin-producing beta-cells of pancreatic islets, of which the capacity for self-replication in the adult is too limited to restore following extensive tissue injury. Tissue inhibitor of metalloproteinase (TIMP)-1 inhibits matrix metalloproteinase activity and regulates proliferation and apoptosis of a variety of cells types, depending on the context. Here, we show that overexpression of human TIMP-1 in pancreatic beta-cells of transgenic mice counteracts the cytotoxicity and insulitis induced by multiple low-dose streptozotocin (MLDS). Nontransgenic mice developed severe hyperglycemia, hypoinsulinemia, and insulitis 2 weeks after streptozotocin administration and died within 17 weeks. However, MLDS-treated transgenic mice gradually normalized the metabolic parameters and survived. beta-Cell mass increased in parallel as a result of enhancement of beta-cell replication. Thus, our results have demonstrated for the first time that overexpression of TIMP-1 in beta-cells enhances the replication of pancreatic islets beta-cells and counteracts type 1 diabetes, indicating that the TIMP-1 gene may be a potential target to prevent, or even reverse, type 1 diabetes.

Animals↗

PubMed2006

Development of a sandwich ELISA for evaluating soluble OX40L (CD252) in human sera of different ages or with Graves' disease.

OX40 ligand (CD252), a molecule originally identified as human gp34, is an important costimulatory molecule during immune response. Here, we describe a sandwich ELISA for the detection and quantification of soluble OX40L using anti-OX40L monoclonal antibodies 1G1 and 4C12 as capture and detecting antibody, respectively. With this ELISA, the existence and concentration of soluble forms of OX40L (sOX40L) was demonstrated for the first time. It was found that soluble OX40L is detectable in the sera of elderly persons (above 60 years old) and patients with Graves' disease which has the highest mean serum concentration of sOX40L, suggesting the potential diagnostic significance of sOX40L in the disease. Surprisingly, the quantitation of sOX40L was correlated with the age and among these subjects, those of 70s and 80s have much higher sOX40L concentration than those of 60s.

Aged↗

PubMed2006

Isolation of mesenchymal stem cells from human placenta: comparison with human bone marrow mesenchymal stem cells.

The presence within bone marrow of a population of mesenchymal stem cells (MSCs) able to differentiate into a number of different mesenchymal tissues, including bone and cartilage, was first suggested by Friedenstein nearly 40 years ago. Since then MSCs have been demonstrated in a variety of fetal and adult tissues, including bone marrow, fetal blood and liver, cord blood, amniotic fluid and, in some circumstances, in adult peripheral blood. MSCs from all of these sources can be extensively expanded in vitro and when cultured under specific permissive conditions retain their ability to differentiate into multiple lineages including bone, cartilage, fat, muscle, nerve, glial and stromal cells. There has been great interest in these cells both because of their value as a model for studying the molecular basis of differentiation and because of their therapeutic potential for tissue repair and immune modulation. However, MSCs are a rare population in these tissues. Here we tried to identify cells with MSC-like potency in human placenta. We isolated adherent cells from trypsin-digested term placentas and examined these cells for morphology, surface markers, and differentiation potential and found that they expressed several stem cell markers. They also showed endothelial and neurogenic differentiation potentials under appropriate conditions. We suggest that placenta-derived cells have multilineage differentiation potential similar to MSCs in terms of morphology and cell-surface antigen expression. The placenta may prove to be a useful source of MSCs.

Adult↗

PubMed2006

TIMP-1 promotes age-related renal fibrosis through upregulating ICAM-1 in human TIMP-1 transgenic mice.

Imbalance of matrix metalloproteinases and tissue inhibitors of metalloproteinases (MMPs/TIMPs) takes part in age-related renal fibrosis; so does molecular inflammation. As several inflammatory mediators including intercellular adhesion molecule-1 (ICAM-1) are substrates of MMPs, we speculated that TIMP-1 might affect ICAM-1 through MMPs and subsequently promote age-related renal fibrosis. Then, we observed changes of kidney in human TIMP-1 transgenic mice and wild-type mice of different ages. It was found that the expressions and activities of gelatinases were downregulated; the expressions of ICAM-1, collagen III, collagen IV, and transforming growth factor (TGF)-beta1 were upregulated; and the number of infiltrating macrophages was increased in kidneys of 24-month-old TIMP-1 transgenic mice with high expressions of TIMP-1, compared with wild-type mice. Our results indicated that TIMP-1 could promote age-related renal fibrosis, which was partly attributed to enhancing inflammation through upregulation of ICAM-1.

Aging↗

PubMed2005

A new human acute monocytic leukemia cell line SHI-1 with t(6;11)(q27;q23), p53 gene alterations and high tumorigenicity in nude mice.

BACKGROUND AND OBJECTIVES: Human leukemia cell lines are of great value in leukemia research. Thus far 36 leukemia cell lines carrying the 11q23 translocation and MLL rearrangements, including two cell lines with t(6;11)(q27;q23) and an MLL-AF6 fusion gene have been described. We have established a new monocytic cell line with t(6;11), designated SHI-1, and herein describe its biological characteristics. DESIGN AND METHODS: Mononuclear cells isolated from the bone marrow of a patient with acute monocytic leukemia (AML-M5b) at relapse were inoculated and passaged by liquid culture. The biological features of the cell line were characterized by morphological assays, flow cytometry, cytogenetic analysis, reverse transcription polymerase chain reaction (RT-PCR), direct sequencing, fluorescence in situ hybridization (FISH), clonogenic culture, quantitative fluorescent PCR, zymography, short tandem repeating sequences-PCR (STR-PCR), multiplex-FISH (M-FISH), and tumorigenic capacity in nude mice. RESULTS: The SHI-1 cell line has been maintained in continuous culture without any external cytokines for three years. The morphology and immunoprofile of the cells show typical features of monocytic lineage. Karyotypic analysis demonstrated a t(6;11)(q27;q23) translocation accompanied by a deletion of 17p, which are the same abnormalities as were seen in the leukemia cells of this patient in relapse. The MLL-AF6 fusion transcript and the loss of one p53 allele were proven by chromosome painting, FISH and RT-PCR analysis in both SHI-1 cells and the primary leukemia cells. A point mutation of ATC-->ACC at codon 195 of exon 6 in another p53 allele was found by direct sequencing of DNA in SHI-1 cells as well as in the primary leukemia cells. Neither Epstein-Barr virus nor mycoplasma was detected in SHI-1 cells. Tumor masses were found in all sixteen mice 9-19 days after subcutaneous injection of SHI-1 cells. DNA fingerprinting confirmed the authenticity of the cell line. INTERPRETATION AND CONCLUSIONS: SHI-1 is a new monocytic leukemia cell line with the t(6;11) translocation, p53 gene alterations, and high tumorigenicity in nude mice. It could be a valuable tool in the study of leukemogenesis.

Adult↗

PubMed2005

Molecular analysis and identification of virulence gene on pR(ST98) from multi-drug resistant Salmonella typhi.

pR(ST98) is a large and conjugative resistant plasmid (R plasmid) of 98.6 mega-dalton from multi-drug resistant Salmonella typhi (S. typhi), which was classified to incompatibility group C (Inc C). It has been found that pRST98 made its host bacteria not only antibiotic resistant but also more virulent. In this study we explored the possibility of plasmid pRST98 in S. typhi carrying the Salmonella plasmid virulence gene - spv. The plasmid pRST98 was isolated, purified and then digested by nine restriction endonucleases to make the plasmid enzyme profile. Spv-specific PCR and Southern blot were applied to identify the virulence gene on pR(ST98). The amplified spv fragments spvR and spvB were cloned into pGEM-T EASY and then the DNA sequences were analysed. The fragments of pRST98 digested by endonucleases Bgl II, Pst I and Sac II were identified, which may be useful for molecular analysis and further epidemiological surveillance of pR(ST98). The results of PCR and Southern blot showed that spv homologous genetic sequence which had been found in all pathogenesis Salmonella spp. except S. typhi was also presented on pR(ST98). The ORF of spvR and spvB of pRST98 were 894 bp and 1,776 bp, respectively. They have more than 99% homology with that of spvR and spvB on virulence plasmid in S. typhmurium. The genotype research on pR(ST98) revealed that there is a plasmid carrying genes responsible for drug resistance and virulence in S. typhi. This is the first report for such kind chimerical plasmid in S. typhi.

Base Sequence↗

PubMed2005

B7-H3: another molecule marker for Mo-DCs?

Using a newly generated monoclonal antibody (2E6) against human B7-H3, we explored the expression of the molecule on dendritic cells derived from monocytes (Mo-DCs). Its expression was examined by means of immunostaining and flow cytometric (FCM) analysis. The results showed that B7-H3 was expressed in the course of Mo-DC maturation induced with interleukin 4 (IL-4) and granulocyte/macrophage colony-stimulating factor (GM-CSF). The expression could be detected at all the stages of Mo-DC differentiation, and remained at a quite stable level. Interestingly, B7-H3 was not expressed by T cells and B cells, even these cells were activated respectively by PHA or PWM. A weak expression could be detected on resting monocytes. These data showed that constitutive expression of B7-H3 at a high level was found on imDCs and mDCs derived from monocytes. Due to no expression on T cells and B cells, we speculate that B7-H3 might be another valuable molecule marker for Mo-DCs.

Animals↗

PubMed2004

Distinct overexpression of Fas ligand on T lymphocytes in aplastic anemia.

Increased expression of Fas by hematopoietic progenitors in aplastic anemia (AA) suggests that Fas/Fas ligand (FasL) system plays a key role in the formation of severe pancytopenia. To further confirm the above hypothesis, T cells from 8 patients with AA were systematically studied for their FasL's distribution pattern, releasing manner and proapoptotic activity, compared with normal resting T cells and artificially activated T cell blasts. The results demonstrated that AA T cells abnormally expressed low levels of membrane-bound FasL and contained high levels of intracellular FasL which could be triggered to release by high-dose phytohemagglutinin (PHA) pulse-stimulation. The supernatants from the PHA-stimulated AA T cells had apparent cytotoxicity against FasL-sensitive Jurkat cells, which could be significantly inhibited by monoclonal antibody against FasL in a dose-dependent manner, or nearly completely abrogated by ultracentrifugation. The above phenomena also appeared on artificially activated T cell blasts, but this was not the case on normal resting T cells. These results indicate that AA T cell is a type of "preactivated" T lymphocyte, characterized by overexpression of FasL, especially intracellular FasL which can be stimulated to release in bioactive exosomes-bound form. Taken together, our data provide further and direct evidence for the hypothesis that T cells might mediate the destruction of hematopoietic progenitor in AA through Fas/FasL system.

Adolescent↗

PubMed2003

Adriamycin increases podocyte permeability: evidence and molecular mechanism.

OBJECTIVE: To investigate the increased podocyte permeability by evidence of adriamycin (AD) and its molecular mechanism. METHODS: In this study, we explored the direct effects of AD on cultured mouse podocytes and the potential protection effects of Dexamethasome (Dex). RESULTS: After 24-hour AD (5 x 10(-7) mol/L) treatment, albumin passage through podocyte monolayers was increased by 2.27-fold (P < 0.01). AD caused a 62% decrease in Zonula Occluden-1 (ZO-1) protein (P < 0.05), suggesting that AD might increase podocyte permeability by disrupting tight junctions. Dex (1 x 10(-6) mol/L), co-administered with AD, protected podocytes from AD-induced increased albumin passage. This may be linked with an increased P-cadherin protein level to 1.93 fold of control (P < 0.01). CONCLUSIONS: AD has a direct, detrimental effect on podocyte permeability, probably through disrupting tight junctions; Dex could protect against AD-induced high podocyte permeability by upregulating adherent protein P-cadherin.

Albumins↗

PubMed2002

Recombinant human Flt3 ligand exerts both direct and indirect effects on hematopoiesis.

OBJECTIVE: To investigate the direct effects of the Flt3 ligand (FL) on hematopoiesis, such as the stimulation of the formation of hematopoietic colonies and the proliferation of dendritic cells, as well as the indirect stimulation of hematopoiesis, especially via the proliferation of endothelial cells. METHODS: Mononuclear cells from human cord blood were plated in methylcellulose medium containing different cytokines to induce hematopoietic colony formation. Dendritic cells (DCs) were induced from the mononuclear cells with a cytokine cocktail with or without recombinant human soluble FL (rhFL; 100 ng/ml). The Flt3 receptors on the surface of a human microvascular endothelial cell line (ECV) were analyzed by flow cytometry. The proliferation of ECV stimulated by rhFL was measured with the microculture tetrazolium assay. The levels of FL, IL-6, IL-8, G-CSF and GM-CSF in the supernatant of ECV cultures were measured by enzyme linked immunoabsorbent assay (ELISA). RESULTS: rhFL stimulates colony formation from cord blood when used as a sole stimulant. FL in combination with other cytokines increased colony formation significantly. The number of DCs was approximately 2.5 times higher when rhFL was used. rhFL stimulates the proliferation of ECV on which Flt3 receptors are expressed. Furthermore, ECV secretes FL, IL-6, IL-8, G-CSF and GM-CSF, which were augmented by tumor necrosis factor-alpha and rhFL. CONCLUSIONS: rhFL enhances hematopoietic colony formation and DC proliferation from human cord blood cells. FL not only stimulates the proliferation of ECV, but is also secreted by ECV. FL may exert direct and indirect effects on hematopoiesis.

Cell Division↗

PubMed2002

[Effect of CD(40) on the in vitro biological behavior of malignant B lymphocytes].

OBJECTIVE: To explore the effect of recombinant human soluble CD(40) ligand (rhsCD(40)L) and CD(40)L cDNA transfected cell (CD(40)L-TC) on the behavior of malignant B lymphocytes, and investigate the possibility of using rhsCD(40)L as a new bio-factor in tumor immunotherapy. METHOD: rhsCD(40)L and CD(40)L-TC were obtained by gene recombinant techniques. Multiple myeloma cell lines, XG2, XG7, U266 and 8226, B-lymphoma cell lines, Raji and Daudi were selected to detect responses to rhsCD(40)L and CD(40)L-TC stimulation. Cell growth curve, cell cycle, early apoptosis as well as membrane surface molecules on these cell lines were analyzed. RESULTS: (1) The expression levels of CD(40) molecule on malignant B lymphocytes showed heterogeneity. High level of CD(40) on XG2, moderate on 8266, Raji, and Daudi, and no expression on U266 and XG7 were detected. The rhsCD(40)L stimulation gave rise to a typical homo-type cell aggregation of XG2 and Daudi. Meanwhile, at least 10 to 20 of CD(40)(+) XG2 or CD(40)(+) Daudi cells were found adherent to one pre-treat ed CD(40)L-TC. (2) Co-incubation with rhsCD(40)L (5 micro g/ml), or CD(40)L-TC (tumor cell: CD(40) = 5:1) resulted in a significant inhibition of in vitro cell growth of XG2, Raji and Daudi, with G(1)-phase arrest for XG2 and G(2)-phase for Raji and Daudi. These two kinds of CD(40) stimulators induced XG2, Raji and Daudi cells to apoptosis in vitro. The apoptotic rate for XG2 was 23.3% (rhsCD(40)L) and 18.8% (CD(40)L-TC), for Daudi 14.2% and 15.9%, and for Raji 11.6% and 8.9% respectively. (3) Phenotype analysis showed that CD(95) expression levels were significantly up-regulated on XG2, Raji and Daudi after stimulation with rhsCD(40)L or CD(40)L-TC, and CD(80) and CD(18) expression levels on Raji were respectively enhanced and decreased. CONCLUSION: The abilities to directly inhibit XG2, Daudi and Raji cell proliferation, to induce themapoptosis, as well as to up-regulate immune co-stimulator molecule CD(80) expression on Raji cells would make rhsCD(40)L a potential bio-factor for tumor immuno-therapy.

B-Lymphocytes↗

PubMed2002

[CD40 ligandization promotes IL-6 and Flt3 ligand production of bone marrow stromal cells].

OBJECTIVE: To analyze the expression of the CD(40) and its ligand (CD(40)L) on bone marrow stromal cells (BMSC), and investigate interleukin-3 (IL-3), IL-6, Flt3 ligand (FL) and stem cell factor (SCF) production of BMSC after stimulated with CD(40) agonistic monoclonal antibody (5C11) and its role in the regulation of hematopoiesis. METHODS: BMSC were freshly isolated from adult bone marrow. The expression of CD(40) on these cells was determined with flow cytometry, the concentrations of IL-3, IL-6, FL and SCF in the supernatant at 24, 48 and 72 hours after BMSC cultured with 5C11 at a dose of 20 micro g/ml were determined by the ELISA assay. After BMSC incubated with 5C11 for 24 hours, the supernatant was collected and cultured with purified cord blood CD(34)(+) cells for 7 days under 37 degrees C in a fully humidified atmosphere supplement with 5% CO(2). Colony formation assay and Annexin V assay were employed to determine the proliferation and apoptosis of the CD(34)(+) cells. RESULTS: BMSC expressed CD(40) and the production of IL-6 and FL increased after stimulated with 5C11 while IL-3 and SCF had no change. The supernatant collected from the stimulated BMSC promoted proliferation of CD(34)(+) cells, increased the CFU-GM yields and had anti-apoptosis effects. CONCLUSION: CD(40) ligandization on BMSC increased the production of IL-6 and FL and promoted the proliferation of CD(34)(+) cells. The couple CD(40)/CD(40)L may be involved in the control of hematopoiesis via modulation of the cytokine network in the bone marrow.

Adult↗