Yanghong Wu

University of Iowa, Iowa City, IA, USA

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Publications (11)33.14 Total impact

  • Article: Enhanced Expression of Glia Maturation Factor Correlates with Glial Activation in the Brain of Triple Transgenic Alzheimer's Disease Mice.
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    ABSTRACT: We previously demonstrated that glia maturation factor (GMF), a brain specific protein, isolated, sequenced and cloned in our laboratory, induce expression of proinflammatory cytokines and chemokines in the central nervous system. We also reported that the up-regulation of GMF in astrocytes leads to the destruction of neurons suggesting a novel pathway of GMF-mediated cytotoxicity of brain cells, and implicated its involvement in the pathogenesis of inflammatory neurodegenerative diseases. In the present study, we examined the expressions of GMF in triple-transgenic Alzheimer's disease (3xTg-AD) mice. Our results show a 13-fold up-regulation of GMF and 8-12-fold up-regulation of proinflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1β, interferon gamma (IFN-γ), and chemokine (C-C motif) ligand 2 (CCL2) and C-X-C motif chemokine 10 (CXCL10/IP-10) mRNA as determined by quantitative real-time RT-PCR in the brain of 3xTg-AD mice as compared to non-transgenic (Non-Tg) mice. In conclusion, the increase in GMF and cytokine/chemokine expression was correlated with reactive glial fibrillary acidic protein positive astrocytes and ionized calcium binding adaptor molecule 1 (Iba-1)-positive microglia in 3xTg-AD mice.
    Neurochemical Research 10/2012; · 2.24 Impact Factor
  • Article: Efficient down-regulation of glia maturation factor expression in mouse brain and spinal cord.
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    ABSTRACT: Long-lasting siRNA-based down-regulation of gene of interest can be achieved by lentiviral-based expression vectors driving the production of short hairpin RNA (shRNA). We investigated an attractive therapeutic approach to target the expression of proinflammatory GMF by using lentiviral vector encoding GMF-specific shRNA to reduce GMF levels in the spinal cord and brain of mice. To determine the effect of GMF-shRNA on GMF protein levels, we performed quantitative ELISA analysis in brain and in thoracic, cervical and lumbar regions of spinal cord from mice followed by GMF-shRNA (G-shRNA) or control shRNA (C-shRNA) treatments. Our results show a marked reduction of GMF protein levels in brain and spinal cord of mice treated with GMF-shRNA compared to control shRNA treatment. Consistent with the GMF protein analysis, the immunohistochemical examination of the spinal cord sections of EAE mice treated with GMF-shRNA showed significantly reduced GMF-immunoreactivity. Thus, the down-regulation of GMF by GMF-shRNA was efficient and wide spread in CNS as evident by the significantly reduced levels of GMF protein in the brain and spinal cord of mice.
    Neurochemical Research 03/2012; 37(7):1578-83. · 2.24 Impact Factor
  • Article: Clinical course of myelin oligodendrocyte glycoprotein 35-55 induced experimental autoimmune encephalomyelitis is aggravated by glia maturation factor.
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    ABSTRACT: The role of glia maturation factor (GMF) in myelin oligodendrocyte glycoprotein (MOG) 35-55 peptide-induced experimental autoimmune encephalomyelitis (EAE) was investigated using GMF-deficient (GMF-KO) mice. We demonstrate that GMF-KO mice were resistant to the MOG 35-55 peptide-induced EAE as compared to wild type (Wt) mice (two in eight versus 10 in 10). Next, we examined the effect of administration of recombinant human GMF (rGMF) on MOG 35-55 peptide-induced EAE in mice. Daily administration of rGMF, staring days 1-14, resulted in significant exacerbation of clinical symptoms. Following rGMF injections, both GMF-KO (six in eight) and Wt mice (eight in eight) developed severe EAE (maximal clinical score of 3.5-4.0) with high frequency. The histological examination revealed severe infiltration of inflammatory cells in the spinal cord of MOG-immunized Wt mice while the resistance to EAE in GMF-KO mice was characterized by the absence of inflammatory cells. Administration of rGMF in Wt mice and GMF-KO mice resulted in a significant increase in infiltrating cells in the spinal cord following MOG-immunizations. We also evaluated cytokines and chemokines production as parameters of severity of inflammation in the spinal cord of Wt versus GMF-KO mice with and without GMF-reconstitution following MOG-immunizations. Cytokines (TNF-α, IFN-γ, IL-1β, IL-6) and chemokines (CCL2, CCL3, CXCL10, GM-CSF) production were significantly greater in Wt mice than in GMF-KO mice following MOG-immunization. Furthermore, the reconstitution experiment with rGMF showed that the administration of rGMF in both, Wt mice and GMF-KO mice produced significant increase in the GMF-mediated cytokine/chemokine production.
    Neurochemistry International 02/2012; 60(3):215-9. · 2.86 Impact Factor
  • Article: Suppression of neuro inflammation in experimental autoimmune encephalomyelitis by glia maturation factor antibody.
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    ABSTRACT: Glia maturation factor (GMF), a protein primarily localized in the central nervous system (CNS) was isolated, sequenced and cloned in our laboratory. We previously demonstrated that GMF mediates the experimental autoimmune encephalomyelitis (EAE)-induced production of pro-inflammatory cytokines and chemokines in the central nervous system of mice. In the present study we show that immunization with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55) caused an early onset (days 7-9 post immunization) and severe EAE with a mean peak score of 3.5 ± 0.5 in mice. Neutralization of GMF with four injections of anti-GMF antibody 5 to 11 days post immunization delayed the time of onset (days 12-14 post immunization) and significantly reduced the severity of EAE (mean peak score of 1.5 ± 0.4). Consistent with these clinical scores, histological examination of the CNS of these mice revealed profound differences between GMF-antibody treated mice and isotype matched control-antibody treated mice. Histological analysis of the spinal cord and brain showed severe inflammation and demyelination in the control antibody-treated mice whereas significantly reduced inflammation and demyelination was detected in GMF-antibody-treated mice at days 8, 16, and 24 post immunization. The decreased incidence and reduced severity of EAE in GMF-antibody-treated mice was consistent with the significantly reduced expressions of pro-inflammatory cytokines and chemokines. Our overall results demonstrate that neutralization of endogenous GMF with an affinity purified GMF antibody significantly decreased the inflammation, severity and progression of immunization induced active, passive and relapsing-remitting EAE. Treatment of mice with isotype-matched control antibody did not have any effect on EAE. Taken together, these results demonstrate the critical role of GMF in EAE, and GMF antibody as a potent anti-inflammatory therapeutic agent for effectively suppressing EAE in mouse models of major types of multiple sclerosis (MS).
    Brain research 02/2011; 1373:230-9. · 2.46 Impact Factor
  • Article: Overexpression of glia maturation factor reinstates susceptibility to myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis in glia maturation factor deficient mice.
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    ABSTRACT: Glia maturation factor (GMF), a primarily CNS localized protein was discovered and characterized in our laboratory. We previously demonstrated that GMF is the upstream regulator for excessive production and release of proinflammatory cytokines/chemokines in brain cells leading to the destruction of oligodendrocytes, the myelin forming cells, and neurons. We also reported that mice lacking endogenous GMF (GMF-deficient, GMF-KO) were resistant to myelin oligodendrocyte glycoprotein peptide 35-55 (MOG(35-55)) induced EAE, since immunization induced only delayed EAE with diminished severity. In the present study we show that a replication-defective adenovirus-GMF construct caused expression of GMF in CNS of GMF-KO mice and reinstated MOG(35-55) induced early and severe EAE. Our results show that MOG(35-55) immunization caused only a muted EAE and inflammation/demyelination in mice lacking endogenous GMF. The diminished incidence of EAE in GMF-KO mice was consistent with the significantly reduced expressions of cytokines/chemokines. The muted severity of EAE in GMF-KO mice was restored to full blown levels upon reintroduction of GMF using an adeno-GMF-virus (Adv-GMF) vector. Consistent with the clinical findings, histological examination of the CNS of mice with EAE revealed profound differences between wild type (Wt), GMF-KO, and GMF-KO mice with re-introduced GMF (GMF-KO+Adv-GMF). Spinal cord sections from mice with EAE were analyzed for the infiltration of mononuclear cells (inflammation) and myelin loss (demyelination). In Wt mice, 40% of spinal cord quadrants were positive for demyelination and 45% of spinal cord quadrants were positive for inflammation at the peak of EAE. Drastically reduced infiltrates (15%) and demyelination (10%) were found in GMF-KO mice that developed reduced severity of EAE. Upon GMF reintroduction in GMF-KO mice, MOG(35-55) immunization caused extensive monocytes infiltration (48%) and demyelination (46%), similar to that observed in the immunized Wt mice. The levels of cytokine/chemokine in the spinal cords of mice at three time points, corresponding to the onset, peak severity and recovery period of EAE, show a distinct pattern of very large increases in IFN-γ, TNF-α, GM-CSF and MCP-1 in Wt and GMF-KO+Adv-GMF mice compared to GMF-KO and GMF-KO+Adv-LacZ mice.
    Neurobiology of Disease 12/2010; 40(3):593-8. · 5.40 Impact Factor
  • Article: Glia maturation factor modulates beta-amyloid-induced glial activation, inflammatory cytokine/chemokine production and neuronal damage.
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    ABSTRACT: Glia maturation factor (GMF), discovered and characterized in our laboratory, is a highly conserved protein primarily localized in mammalian central nervous system. Previously we demonstrated that GMF is required in the induced production of proinflammatory cytokines and chemokines in brain cells. We now report that ventricular infusion of human amyloid beta peptide1-42 (Abeta1-42) in mouse brain caused glial activation and large increases in the levels of GMF as well as induction of inflammatory cytokine/chemokine known for launching the neuro inflammatory cascade in Alzheimer's disease (AD). To test the hypothesis that GMF is involved in the pathogenesis of AD, we infused Abeta1-42 in the brain of GMF-deficient (GMF-KO) mice, recently prepared in our laboratory. GMF-deficient mice showed reduced glial activation and significantly suppressed proinflammatory cytokine/chemokine production following Abeta infusion compared to wild type (Wt) mice. The decrease in glial activation in the GMF-KO mice is also associated with significant reduction in Abeta induced loss of pre-synaptic marker, synaptophysin, and post-synaptic density protein-95 (PSD 95). We also examined the potential relationship between GMF or lack of it with learning and memory using the T-maze, Y-maze, and water maze, hippocampal-dependent spatial memory tasks. Our results show that memory retention was improved in GMF-KO mice compared to Wt controls following Abeta infusion. Diminution of these Abeta1-42 effects in primary cultures of GMF-KO astrocyte and microglia were reversed by reconstituted expression of GMF. Taken together, our results indicate a novel mediatory role of GMF in the neuro-inflammatory pathway of Abeta and its pro-inflammatory functions.
    Brain Research 06/2008; 1208:192-203. · 2.73 Impact Factor
  • Article: Glia maturation factor regulation of STAT expression: a novel mechanism in experimental autoimmune encephalomyelitis.
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    ABSTRACT: Inflammatory cytokines are implemented in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. We previously demonstrated that glia maturation factor (GMF), a brain protein, isolated, sequenced and cloned in our laboratory, induce expression of proinflammatory cytokine/chemokine in the central nervous system (CNS). We found GMF-deficient (knockout) mice relatively resistant to EAE development after immunization with encephalitogenic MOG peptide 35-55. Consistent with these findings, the expression of proinflammatory cytokines in CNS of mice with EAE differed profoundly between wild type and GMF-knockout mice. In the present study we examined the expressions of six murine signal transducers and activators of transcription (STATs) genes, which are known to regulate the cytokine-dependent signal transduction pathways in autoimmune inflammation. The expressions of STATs genes were evaluated in the brains and spinal cords of wild type and GMF-knockout mice at the peak of EAE by quantitative real-time RT-PCR. Compared to GMF-knockout mice, the expressions of STAT1, STAT2, STAT3, STAT4, STAT5, and STAT6 genes were significantly (P < 0.001) upregulated in the wild type mice exhibiting EAE symptoms. The results are consistent with the diminished development of EAE in the GMF-knockout mice. A significant suppression of STATs expression in GMF-knockout mice suggests GMF as an upstream effector of JAK/STAT signaling.
    Neurochemical Research 12/2007; 32(12):2123-31. · 2.24 Impact Factor
  • Article: Diminished degradation of myelin basic protein by anti-sulfatide antibody and interferon-gamma in myelin from glia maturation factor-deficient mice.
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    ABSTRACT: In this study we show the effect of anti-sulfatide (RmAb) antibodies and inflammatory cytokines, TNF-alpha and IFN-gamma in inducing myelin basic protein (MBP) degradation in myelin isolated from control wild type (WT) and glia maturation factor (GMF)-deficient (GMF-KO) mice. GMF was not detected in isolated myelin from WT and GMF-KO mice although it is present in brains of WT mice. Our results show that calcium-dependent neutral protease activity caused significantly elevated degradation of 18.5 and/or 17.5kDa isoforms of MBP in WT myelin treated with RmAb or IFN-gamma. In contrast, MBP degradation in isolated myelin from GMF-KO mice remained unaffected following treatment with RmAb, IFN-gamma, or GM-CSF. Neither the 14kDa isoform of MBP nor proteolipid protein (PLP) showed an elevated degradation compared to controls. A virtual absence of GM-CSF, TNF-alpha and IFN-gamma in GMF-KO brain compared to WT was also evident when the animals were challenged with MOG 35-55. Additionally, the myelin from GMF-KO mice showed difference in distribution of myelin oligodendrocyte glycoprotein (MOG) and beta-tubulin in a sucrose density gradient myelin-axolemmal fractions compared to WT. Taken together, our data suggests a role for GMF in the biochemical organization of myelin and thereby its effect on MBP degradation induced by RmAb and IFN-gamma.
    Neuroscience Research 07/2007; 58(2):156-63. · 2.25 Impact Factor
  • Article: Diminished cytokine and chemokine expression in the central nervous system of GMF-deficient mice with experimental autoimmune encephalomyelitis.
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    ABSTRACT: Pro-inflammatory cytokines/chemokines are implemented in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model with clinical and pathological similarities to multiple sclerosis. We have previously shown that over-expression of glia maturation factor (GMF) in glial cells cause excessive production and secretion of pro-inflammatory cytokines/chemokines sufficient to destroy the myelin-forming oligodendroglial cell in vitro. In this present investigation, we evaluate the expression of pro-inflammatory mediators in the central nervous system (CNS) of GMF+/+ (wild type) mice and GMF-/- (GMF-knockout) mice at the peak of EAE induced by immunization with MOG 35-55 peptide. GMF+/+ (Wt) mice developed severe EAE with a maximal mean clinical score of 3.6+/-0.5 by day 16 post-immunization, whereas GMF-KO mice showed significantly delayed EAE with an average onset on day 26 pi with reduced mean clinical score of 1.3+/-0.3. Three of fifteen Wt mice as compared to none of GMF-KO mice died of EAE. Encephalitogenic cells from Wt mice transferred to recipient GMF-KO mice caused very mild and with low incidence of EAE. We determined the differences in the expression of cytokines, IFN-gamma, TNF-alpha, IL-1 beta, IL-6, IL-4, IL-10, and chemokines, MIP-1, MIP-2, IP-10, MCP-1, GM-CSF mRNA by quantitative real-time RT-PCR in brain and spinal cord. Our results demonstrate significantly low levels of pro-inflammatory cytokines/chemokines in the CNS of GMF-KO mice and increased expression in Wt mice with EAE. Our data suggest that GMF play a critical role in CNS inflammation.
    Brain Research 06/2007; 1144:239-47. · 2.73 Impact Factor
  • Article: Chronic Pseudomonas aeruginosa infection reduces surfactant levels by inhibiting its biosynthesis.
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    ABSTRACT: Chronic Pseudomonas aeruginosa infection, as occurs in cystic fibrosis, is associated with decreased surfactant phospholipid levels. To investigate mechanisms, we measured synthesis of dipalmitoylphosphatidylcholine (DPPC), the major surfactant phospholipid. Mice received an agarose bead slurry alone, or were infected with beads containing a clinical mucoid isolate of P. aeruginosa. Bacterial infection after 3 days resulted in a approximately 50% reduction in surfactant DPPC content versus control. These changes in surfactant were associated with co-ordinate reductions in mRNAs and immunoreactive levels for CTP: phosphocholine cytidylyltransferase (CCTalpha), the rate-regulatory enzyme required for DPPC synthesis. P. aeruginosa infection of murine lung epithelia decreased CCTalpha gene transcription without altering mRNA stability and by a mechanism other than release of a soluble extracellular inhibitor. Promoter deletional analysis revealed that P. aeruginosa activates a negative response element from -1019 to -799 bp of the CCTalpha proximal 5'-flanking region. Exposure of cells to a P. aeruginosa mutant strain producing alginate reduced CCTalpha promoter activity, whereas these effects were not observed in strains defective in alginate synthesis. Murine type II cells isolated from P. aeruginosa-infected CCTalpha promoter-beta-galactosidase transgenic mice exhibited significantly reduced CCT and beta-galactosidase enzyme activities versus control. Thus, a mucoid P. aeruginosa strain reduces mRNA synthesis of a key biosynthetic enzyme thereby decreasing levels of surfactant.
    Cellular Microbiology 05/2007; 9(4):1062-72. · 5.46 Impact Factor
  • Article: Transferrin microheterogeneity in pregnancies with preeclampsia.
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    ABSTRACT: It has been reported that concentrations of serum transferrin (Tf) and its highly sialylated subfraction increase in normal pregnancy. This study investigated changes in the concentrations of serum transferrin and its subfractions in preeclampsia. The serum concentration of transferrin was determined by a standard turbidimetric assay and microheterogeneous transferrin subgroups (low sialylated, 4-sialo and highly sialylated transferrins) were assessed by crossed immuno-isoelectric focusing. Compared to normal pregnancy, the concentrations of total, 4-sialo and highly sialylated transferrins decreased by 27%, 16% and 38%, respectively, in severe preeclampsia, while these values did not significantly decrease in mild preeclampsia. The concentration of low sialylated transferrin involving 2-sialo- and 3-sialo-transferrins significantly decreased both in mild and severe preeclampsia, the value in severe preeclampsia was even significantly lower than that in nonpregnant women. The serum concentrations of total and highly sialylated transferrins in preeclampsia were correlated positively with infant birth weights (r=0.587 and r=0.645, respectively). The serum concentrations of total and highly sialylated transferrins in severe preeclampsia decrease significantly. This might have a negative impact on intrauterine growth. Additionally, the serum low sialylated transferrin decreases more sensitively in preeclampsia, although the concentration is low even in normal pregnancy.
    Clinica Chimica Acta 07/2003; 332(1-2):103-10. · 2.54 Impact Factor