Biomedical subjects
Tong Zhou
Publications and source records attributed to Tong Zhou.
Effect of tetramethylpyrazine on P-selectin and hepatic/renal ischemia and reperfusion injury in rats.
AIM: To investigate the effect of tetramethylpyrazine on hepatic/renal ischemia and reperfusion injury in rats. METHODS: Hepatic/renal function, histopathological changes, and hepatic/renal P-selectin expression were studied with biochemical measurement and immunohistochemistry in hepatic/renal ischemia and reperfusion injury in rat models. RESULTS: Hepatic/renal insufficiency and histopathological damage were much less in the tetramethylpyrazine-treated group than those in the saline-treated groups. Hepatic/renal P-selectin expression was down regulated in the tetramethylpyrazine-treated group. CONCLUSION: P-selectin might mediate neutrophil infiltration and contribute to hepatic/renal ischemia and reperfusion injury. Tetramethylpyrazine might prevent hepatic/renal damage induced by ischemia and reperfusion injury through inhibition of P-selectin.
Effect of P-selectin monoclonal antibody on metastasis of gastric cancer and immune function.
AIM: To investigate the effect of cell adhesion molecule P-selectin monoclonal antibody (Mab) on metastasis and immune function of mice orthototopically implanted with human gastric cancer tissue. METHODS: SCID mice were implanted orthotopically with SGC-7901 human gastric carcinoma tissue. Starting from day 3 after operation, animals were given intravenously PBS or P-selectin Mab (100 microg/injection) (for both normal mice and tumor-implanted mice with tumors), twice weekly for 3 weeks. Two animals in each group were sacrificed randomly at the 1st, 2nd, 4th week and 6th week. While T cell and B cell transformation indices were determined with the (3)H TdR infiltration method, the NK cell activity was detected by the LDH release method. RESULTS: The metastatic rate in the P-selectin Mab treated group was lower than that in the PBS treated group (with tumors). The NK activity of normal mice increased over time. The immune functions (T, B cell function, NK activity) of the tumor group in the 6th week were significantly lower than those in the 4th week, but the change was attenuated by P-selectin Mab. CONCLUSION: P-selectin Mab could suppress the metastasis of gastric cancer with no adverse effect on host immune function.
[Cloning, expression of the lectin-EGF domain of P-selectin, and preparation of its monoclonal antibody].
To prepare monoclonal antibody specific to P-selectin lectin-EGF domain, the gene for lectin-EGF domain of P-selectin L-EGF was amplified from normal human platelets by RT-PCR, then was cloned into prokaryotic vector pET42b(+). The recombinant plasmid was transformed into E. coli DH5 alpha strain for further screening and characterization, and was expressed in E. coli BL21 strain. Expressed protein was purified by chromatography on a Ni(2+)-NTA superflow agarose column and eluted with pH 8.0-4.5 urea gradient. Then the mAb anti-lectin-EGF was prepared with classical hybridoma technique, and 3 hybridoma cell lines (B10, F3 and H5) were obtained with Ig subclasses of these mAbs were IgG(2), IgG(1), and IgG(3) respectively, and their light chains were all kappa chain. Immuofluorescence and FACS assays demonstrated that mAbs could specifically recognize P-selectin expressed on ECV (endothelial cell line) stimulated by LPS. Meanwhile, the role of mAbs to P-selectin lectin-EGF domain was studied, and it was proved that the mAbs markedly inhibited adhesion between platelets and neutrophils in vitro. These monoclonal antibodies can specifically recognize the natural P-selectin and markedly inhibit adhesion between platelets and neutrophils in vitro.
[Localization and role of dendritic cells in rat kidney with renal ischemia/ reperfusion injury].
OBJECTIVE: To investigate the localization and the role of dendritic cells (DCs) in rat kidney with renal ischemia/reperfusion injury, and to explore the effect of anti-P-selectin Lectin-epidermal growth factor (EGF) domain monoclonal antibody (PsL-EGFmAb) on DCs. METHODS: (1)Rat model of renal ischemia/reperfusion was established and rats were divided into treated group with PsL-EGFmAb (n=20) and untreated group (n=20), which included four sub-groups respectively according to reperfusion time (1-hour,3-hour, 6-hour, 24-hour), sham group (n=5) severed as control. CD1a(+)CD80(+)DC was observed with microscopy images method and P-selectin was analysed with immunohistochemistry. RESULTS: (1)In renal tissues of untreated group, CD1a(+)CD80(+)DC was found in renal tubules, interstitium and vessels, especially in renal tubules and interstitium, but DCs were hardly observed in sham group (P<0.001). The number of CD1a(+)CD80(+)DC in 24-hour group was greater than those in other groups (P<0.01). The number of DCs was positively associated with blood urea nitrogen and serum creatinine (both P<0.05). (2)P-selectin content was increased significantly after ischemia/reperfusion 1 hour. (3)The contents of DC and P-selectin were decreased after treated (P<0.05 and P<0.01) in rat renal tissues. CONCLUSION: DCs play an important role in immune pathogenesis after renal ischemia/reperfusion injury, which is related to renal immigration of DCs mediated by P-selectin. PsL-EGFmAb may inhibit local DCs immigration and accumulation in kidney.
Bisindolylmaleimide VIII enhances DR5-mediated apoptosis through the MKK4/JNK/p38 kinase and the mitochondrial pathways.
Bisindolylmaleimide VIII (Bis VIII) has been previously shown to enhance Fas-mediated apoptosis through a protein kinase C-independent mechanism. In the present study, we examined the effect of Bis VIII on apoptosis induced by DR5 (TRAIL-R2), using an agonistic anti-human DR5 monoclonal antibody, TRA-8. Our results demonstrated that Bis VIII was able to enhance the apoptosis-inducing activity of TRA-8 both in vitro and in vivo. The combination of TRA-8 and Bis VIII led to a synergistic and sustained activation of the c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase, which was mediated by MAPK kinase 4 and was caspase-8-dependent. The mitochondrial pathway is involved in the synergistic induction of apoptosis by Bis VIII and TRA-8. Bis VIII alone induced the loss of mitochondrial membrane potential in a caspase-independent fashion without subsequent release of cytochrome c. However, in the presence of Bis VIII, TRA-8 induced more profound loss of mitochondrial membrane potential and release of cytochrome c. These results suggest that the enhanced and persistent activation of the JNK/p38 and the decreased mitochondrial membrane potential play a crucial role in synergistic induction of the death receptor-mediated apoptosis by Bis VIII. The unique ability of Bis VIII to enhance DR5-mediated apoptosis signal transduction discloses a potential utility of this compound in combination with anti-DR5 antibody in cancer therapy.
Conversion of phosphoglycolate to phosphate termini on 3' overhangs of DNA double strand breaks by the human tyrosyl-DNA phosphodiesterase hTdp1.
Mammalian cells contain potent activity for removal of 3'-phosphoglycolates from single-stranded oligomers and from 3' overhangs of DNA double strand breaks, but no specific enzyme has been implicated in such removal. Fractionated human whole-cell extracts contained an activity, which in the presence of EDTA, catalyzed removal of glycolate from phosphoglycolate at a single-stranded 3' terminus to leave a 3'-phosphate, reminiscent of the human tyrosyl-DNA phosphodiesterase hTdp1. Recombinant hTdp1, as well as Saccharomyces cerevisiae Tdp1, catalyzed similar removal of glycolate, although less efficiently than removal of tyrosine. Moreover, glycolate-removing activity could be immunodepleted from the fractionated extracts by antiserum to hTdp1. When a plasmid containing a double strand break with a 3'-phosphoglycolate on a 3-base 3' overhang was incubated in human cell extracts, phosphoglycolate processing proceeded rapidly for the first few minutes but then slowed dramatically, suggesting that the single-stranded overhangs gradually became sequestered and inaccessible to hTdp1. The results suggest a role for hTdp1 in repair of free radical-mediated DNA double strand breaks bearing terminally blocked 3' overhangs.
Depletion of collagen II-reactive T cells and blocking of B cell activation prevents collagen II-induced arthritis in DBA/1j mice.
Collagen II (CII)-induced arthritis in DBA/1j mice is mediated by both CII-reactive T cells and anti-CII Ab-producing B cells. To determine the relative role of these processes in the development of arthritis, we specifically eliminated CII-reactive T cells by treating the mice with CII-pulsed syngeneic macrophages that had been transfected with a binary adenovirus system. These macrophages express murine Fas ligand in a doxycycline-inducible manner with autocrine suicide inhibited by concomitant expression of p35. The mice were treated i.v. with four doses of CII-APC-AdFasLp35Tet or a single dose of AdCMVsTACI (5 x 10(9) PFU), or both simultaneously, beginning 2 wk after priming with CII in CFA. Treatment with CII-APC-AdFasLp35Tet alone or in combination with a single dose of AdCMVsTACI prevented the development of CII-induced arthritis and T cell infiltration in the joint. The elimination of T cells was specific in that a normal T cell response was observed on stimulation with OVA after treatment with CII-APC-AdFasLp35Tet. Treatment with AdCMVsTACI alone prevented production of detectable levels of circulating anti-CII autoantibodies and reduced the severity of arthritis but did not prevent its development. These results indicate that the CII-reactive T cells play a crucial role in the development of CII-induced arthritis and that the anti-CII Abs act to enhance the development of CII-induced arthritis.
Mutation, specialization, and hypersensitivity in highly optimized tolerance.
We introduce a model of evolution in which competing organisms are represented by percolation lattice models. Fitness is based on the number of occupied sites remaining after removing a cluster connected to a randomly selected site. High-fitness individuals arising through mutation and selection must trade off density versus robustness to loss, and are characterized by cellular barrier patterns that prevent large cascading losses to common disturbances. This model shows that Highly Optimized Tolerance (HOT), which links complexity to robustness in designed systems, arises naturally through Darwinian mechanisms. Although the model is a severe abstraction of biology, it produces a surprisingly wide variety of micro- and macroevolutionary features strikingly similar to real biological evolution.
Blood dendritic cells interact with splenic marginal zone B cells to initiate T-independent immune responses.
Marginal zone (MZ) and B1 B lymphocytes participate jointly in the early immune response against T-independent (TI) particulate antigens. Here we show that blood-derived neutrophil granulocytes and CD11c(lo) immature dendritic cells (DC) are the primary cells that efficiently capture and transport particulate bacteria to the spleen. In a systemic infection, CD11c(lo) DC, but not neutrophils, provide critical survival signals, which can be inhibited by TACI-Fc, to antigen-specific MZ B cells and promote their differentiation into IgM-secreting plasmablasts. In a local TI response, peritoneal cavity macrophages provide similar support to B1 B-derived Ag-specific blasts. In the absence of soluble TACI ligands, Ag-activated MZ- and B1-derived blasts lack survival signals and undergo apoptosis, resulting in severely impaired antibody responses.
Developmental exposure to brominated diphenyl ethers results in thyroid hormone disruption.
The objective of the current study was to characterize the effects of DE-71 (a commercial polybrominated diphenyl ether mixture containing mostly tetra- and penta-bromodiphenyl ethers) on thyroid hormones and hepatic enzyme activity in offspring, following perinatal maternal exposure. Primiparous Long-Evans rats were orally administered DE-71 (0, 1, 10, and 30 mg/kg/day) in corn oil from gestation day (GD) 6 to postnatal day (PND) 21. Serum and liver samples obtained from dams (GD 20 and PND 22), fetuses (GD 20), and offspring (PNDs 4, 14, 36, and 90) were analyzed for circulating total serum thyroxine (T(4)) and triiodothyronine (T(3)), or hepatic microsomal ethoxy- and pentoxy-resorufin-O-deethylase (EROD and PROD), and uridine diphosphoglucuronosyl transferase (UDPGT) activity. There were no significant effects of treatment on maternal body weight gain, litter size, or sex ratio, nor were there any effects on any measures of offspring viability or growth. Serum T(4) was reduced in a dose-dependent manner in fetuses on GD 20 (at least 15%) and offspring on PND 4 and PND 14 (50 and 64% maximal in the 10 and 30 mg/kg/day groups, respectively), but recovered to control levels by PND 36. Reduction in serum T(4) was also noted in GD 20 dams (48% at highest dose), as well as PND 22 dams (44% at highest dose). There was no significant effect of DE 71 on T(3) concentrations at any time in the dams or the offspring. Increased liver to body weight ratios in offspring were consistent with induction of EROD (maximal 95-fold), PROD (maximal 26-fold) or UDPGT (maximal 4.7-fold). Induction of PROD was similar in both dams and offspring; however, EROD and UDPGT induction were much greater in offspring compared to dams (EROD = 3.8-fold; UDPGT = 0.5-fold). These data support the conclusion that DE-71 is an endocrine disrupter in rats during development.
Tumor necrosis factor-related apoptosis-inducing ligand induces caspase-dependent interleukin-8 expression and apoptosis in human astroglioma cells.
Among the tumor necrosis factor (TNF) family of cytokines, FasL and TNF-related apoptosis-inducing ligand (TRAIL) are known to induce cell death via caspase activation. Recently, other biological functions of these death ligands have been postulated in vitro and in vivo. It was previously shown that Fas ligation induces chemokine expression in human glioma cells. In this study, we investigated whether the TRAIL-DR5 system transduces signals similar to those induced by other TNF family ligands and receptors. To address this issue, two human glioma cell lines, CRT-MG and U87-MG, were used, and an agonistic antibody against DR5 (TRA-8) and human recombinant TRAIL were used to ligate DR5. We demonstrate that DR5 ligation by either TRAIL or TRA-8 induces two functional outcomes, apoptosis and expression of the chemokine interleukin-8 (IL-8); the nonspecific caspase inhibitor Boc-D-Fmk blocks both TRAIL-mediated cell death and IL-8 production; the caspase 3-specific inhibitor z-DEVD-Fmk suppresses TRAIL-mediated apoptosis but not IL-8 induction; caspase 1- and 8-specific inhibitors block both TRAIL-mediated cell death and IL-8 production; and DR5 ligation by TRAIL mediates AP-1 and NF-kappaB activation, which can be inhibited by caspase 1- and 8-specific inhibitors. These findings collectively indicate that DR5 ligation on human glioma cells leads to apoptosis and that the activation of AP-1 and NF-kappaB leads to the induction of IL-8 expression; these responses are dependent on caspase activation. Therefore, the TRAIL-DR5 system has a role not only as an inducer of apoptotic cell death but also as a transducer for proinflammatory and angiogenic signals in human brain tumors.
Specific deletion of autoreactive T cells by adenovirus-transfected, Fas ligand-producing antigen-presenting cells.
Immune privilege is a unique strategy developed in several internal organs that can prevent the development of immune attack against these vital organs. One critical mechanism of immune privilege is utilization of Fas/FasL-mediated apoptosis to delete the invading T cells at the immune privilege sites. In this article, we describe the development and application of a unique cell-gene therapy to correct defective FasL-mediated apoptosis and autoimmune disease in autoimmune mice. This cell-gene therapy strategy using antigen-presenting cells (APCs) to express FasL is not only a therapeutic tool, but also has allowed us to understand the complexity of T cell regulation and the concept of eliminating T cells in the spleen, lymph node, or elsewhere in vivo to regulate the homeostasis of the peripheral T cell response. In this regard, the FasL-expressing APCs can be considered as circulating and regulatable immune privilege sites. Our studies provide substantial evidence that FasL-expressing APCs can be introduced exogenously without liver toxicity to eliminate infiltrating T cells and prevent the development of immune attack in lung, liver, kidney, joint, and salivary gland. Therefore, given the hazardous potential of persistent T cell invasion at the local inflammatory site, it is tempting to speculate that such an endogenous control mechanism occurs normally in vivo to limit a chronic T cell inflammatory response.
Immunobiology of tumor necrosis factor receptor superfamily.
The proteins of the tumor necrosis factor (TNF) receptor superfamily are a group of cell-surface receptors critically involved in the maintenance of homeostasis of the immune system. By interacting with their corresponding ligands, these receptors either induce cell death or promote cell survival of immune cells. The number of recognized members of the TNF receptor and ligand superfamily has expanded substantially in the last several years. More important, the biologic function of this group of proteins has been closely associated with the regulation of the immune response and the pathogenesis of autoimmune disease. Thus, the direct targeting of these receptors by either inducing apoptosis or blocking survival of autoimmune T and B cells may be an important therapeutic strategy in the treatment of autoimmune disease. This review summarizes the recent progress in immunobiology of the TNF receptor superfamily and focuses on our studies of three critical family members-FasL/Fas, TNF-related apoptosis-inducing ligand (TRAIL)/TRAIL-Rs, and B lymphocyte stimulator(BLyS)/BLyS-Rs--to demonstrate the therapeutic potential of targeting these receptors for the treatment of autoimmune disease.
Effect of N-desulfated heparin on hepatic/renal ischemia reperfusion injury in rats.
AIM: To investigate the effect of N-desulfated heparin on hepatic/renal ischemia and reperfusion injury in rats. METHODS: Using rat models of 60 minutes hepatic or renal ischemia followed by 1 h,3 h,6 h and 24 h reperfusion,animals were randomly divided into following groups,the sham operated controls,ischemic group receiving only normal saline,and treated group receiving N-desulfated heparin at a dose of 12 mg/kg at 5 minutes before reperfusion. P-selectin expression was detected in hepatic/renal tissues with immunohistochemistry method. RESULTS: P-selectin expression, serum ALT, AST, BUN and Cr levels were significantly increased during 60 minute ischemia and 1 h, 3 h, 6 h and 24 h reperfusion,while the increment was significantly inhibited,and hepatic/renal pathology observed by light microscopy was remarkably improved by treatment with the N-desulfated heparin. Furthermore,the heparin was found no effects on PT and KPTT. CONCLUSION: P-selectin might mediate neutrophil infiltration and contribute to hepatic/renal ischemia and reperfusion. The N-desulfated heparin might prevent hepatic/renal damage induced by ischemia and reperfusion injury without significant anticoagulant activity.
Role of P-selectin and anti-P-selectin monoclonal antibody in apoptosis during hepatic/renal ischemia reperfusion injury.
AIM:To evaluale the potential role of P-selectin and anti-P-selectin monoclonal antibody (mAb) in apoptosis during hepatic/renal ischemia-reperfusion injury.METHODS:Plasma P-selectin level, hepatic/renal P-selectin expression and cell apoptosis were detected in rat model of hepatic/renal ischemia-reperfusion injury.ELISA,immunohist ochemistry and TUNEL were used. Some ischemia-reperfusion rats were treated with anti-P-selectin mAb.RESULTS:Hepatic/renal function insuffic-iency, up-regulated expression of P-selectin in plasma and hepatic/renal tissue, hepatic/renal histopathological damages and cell apoptosis were found in rats with hepatic/renal ischemia-reperfusion injury, while these changes became less conspi-cuous in animals treated with anti-P-selectin mAb.CONCLUSION:P-selectin might mediate neutrophil infiltration and cell apoptosis and contribute to hepatic/renal ischemia-reperfusion injury, anti-P-selectin mAb might be an efficient approa-ch for the prevention and treatment of hepatic/renal ischemia reperfusion injury.
Cluster analysis of the codon use frequency of MHC genes from different species.
The relative synonymous codon use frequency of 135 MHC genes from four mammal species (Homo sapiens, Pan troglodyte, Macaca mulanta and Rattus norvegicus) is analyzed using a hierarchical cluster method. The result suggests that gene function is the dominant factor that determines codon usage bias, while species is a minor factor that determines further difference in codon usage bias for genes with similar functions. The conclusion may be useful in gene classification and gene function prediction.