Jun Dong

University of Nebraska Medical Center, Omaha, Nebraska, United States

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Publications (10)16.69 Total impact

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    ABSTRACT: Curcumin is a molecule found in turmeric root that has anti-inflammatory, antioxidant, and anti-tumor properties and has been widely used as both an herbal drug and a food additive to treat or prevent neurodegenerative diseases. To explore whether curcumin is able to ameliorate HIV-1-associated neurotoxicity, we treated a murine microglial cell line (N9) and primary rat cortical neurons with curcumin in the presence or absence of neurotoxic HIV-1 gp120 (V3 loop) protein. We found that HIV-1 gp120 profoundly induced N9 cells to produce reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1). HIV-1 gp120 also induced apoptosis of primary rat cortical neurons. Curcumin exerted a powerful inhibitory effect against HIV-1 gp120-induced neuronal damage, reducing the production of ROS, TNF-α and MCP-1 by N9 cells and inhibiting apoptosis of primary rat cortical neurons. Curcumin may exert its biological activities through inhibition of the delayed rectification and transient outward potassium (K(+)) current, as curcumin effectively reduced HIV-1 gp120-mediated elevation of the delayed rectification and transient outward K(+) channel current in neurons. We conclude that HIV-1 gp120 increases ROS, TNF-α and MCP-1 production in microglia, and induces cortical neuron apoptosis by affecting the delayed rectification and transient outward K(+) channel current. Curcumin reduces production of ROS and inflammatory mediators in HIV-1-gp120-stimulated microglia, and protects cortical neurons against HIV-1-mediated apoptosis, most likely through inhibition of HIV-1 gp120-induced elevation of the delayed rectification and transient outward K(+) current.
    PLoS ONE 01/2013; 8(8):e70565. · 3.73 Impact Factor
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    ABSTRACT: To investigate the protective effect and mechanism of curcumin against ActD/TNF-α-induced synergistically apoptosis in PC12 cells. MTT assay was used to evaluate the optimal concentration of drugs; Hoechst 33258 fluorescent staining to observe apoptosis of PC12 cells, JC-1 was used to detect the mitochondrial membrane potential (MMP), real-time PCR was used to detect the expression of two apoptotic genes: Bcl-1 and Bax. RESUITS: ActD/TNF-α can synergistically reduce viability of PC12 cells(P<0.05), increase the number of cells with pyknosis and karyorrhexis, increase apoptotic rate of cells (P<0.05), decrease MMP in cells, and downregulate expression of Bcl-2(P<0.05). After treating with curcumin(5 μmol/L), survival of PC12 cells was increased(P<0.05), the number of cells with pyknosis and karyorrhexis was reduced, MMP and expression of Bcl-2 were increased(P<0.05). Curcumin can resist the ActD/TNF-α-induced synergistically apoptosis in PC12 cells, the mechanisms of which may be related to an increase in MMP and Bcl-2 expression.
    Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 05/2012; 28(5):484-7.
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    ABSTRACT: In addition to its well-characterized effects in immune system, chemokine CC motif ligand 2 (CCL2, formerly known as monocyte chemoattractant protein-1) is believed to play an important role in brain physiological and pathological processes. It has been shown that CCL2 and its cognate receptor chemokine CC motif receptor 2 are constitutively expressed in several brain regions including the hippocampus, and the expression is up-regulated under pathological conditions. Whereas most investigations have so far focused on its involvement in CNS pathology, few studies have examined the effects of CCL2 on neuronal and synaptic physiology. In this study, we tested the effects of CCL2 on neuronal excitability and excitatory synaptic transmission in the CA1 region of rat hippocampal slices using whole-cell patch clamp techniques. Bath application of CCL2 depolarized membrane potential and increased spike firing in CA1 neuronal cells. Bath application of CCL2 also produced an increase of excitatory post-synaptic currents recorded in Schaffer-collateral fibers to CA1 synapses. Quantal analysis revealed that CCL2 increased the frequency of spontaneous excitatory post-synaptic current occurrence and mean quantal content. Taken together, our data indicate that CCL2 enhances neuronal excitability and synaptic transmission via pre-synaptic mechanisms. These results support the emerging concept that chemokines function as neuromodulators in the CNS.
    Journal of Neurochemistry 02/2011; 116(3):406-14. · 3.97 Impact Factor
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    ABSTRACT: Human immunodeficiency virus-1 (HIV-1)-associated dementia (HAD) is a significant consequence of HIV infection. Although highly active antiretroviral therapy (HAART) has dramatically decreased HIV-1 load in acquired immune deficiency syndrome (AIDS) patients, HAART does not completely protect against the development of HAD, therefore novel strategies for the prevention and treatment are urgently needed. In this study, we chose curcumin which has a neuroprotective role and tested the effect against neuron damage induced by HIV-1gp120 V3 loop peptide. Rats were given 150 ng gp120 V3 peptide by intracerebroventricular (ICV) infusion for 3 days to establish the cognitive dysfunction model. After recovery from the surgery, the rats in treatment groups were given curcumin by intragastric infusion for 2 weeks. Subsequently, we used the Morris water maze test, long-term potentiation (LTP) recording, biochemical measurement of oxidative damage, Nissl staining, and BDNF immunostaining to evaluate the neuropathological changes and the effect of curcumin on rats. Our results documented that the gp120 V3 peptide induced impairment of spatial learning and memory, inhibited LTP in the CA1 region of the hippocampus, and mediated oxidative stress and neuronal injury. These impairments were ameliorated by intragastric infusion of curcumin. These results suggested that dietary supplementation of curcumin may be a potential therapeutic strategy for the treatment and/or prevention of HAD.
    Life sciences 05/2009; 85(1-2):1-10. · 2.56 Impact Factor
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    ABSTRACT: Increasing evidence suggests that many neurons may die through apoptosis in Alzheimer's disease (AD). Mitochondrial dysfunction has been implicated in this process of neuronal cell death. One promising approach for preventing AD is based upon anti-apoptosis to decrease death of nerve cells. In this study, we observed the memory improving properties of curcumin in mice and investigated the neuroprotective effect of curcumin in vitro and in vivo. The mice were given AlCl(3) orally and injections of D-galactose intraperitoneally for 90 days to establish the AD animal model. From day 45, the curcumin group was treated with curcumin for 45 days. Subsequently, the step-through test, neuropathological changes in the hippocampus and the expression of Bax and Bcl-2 were carried out to evaluate the effect of curcumin on the AD model mice. In cultured PC12 cells, AlCl(3) exposure induced apoptosis. The MTT assay was used to measure cell viabilities; flow cytometric analysis to survey the rate of cell apoptosis; DNA-binding fluorochrome Hoechst 33258 to observe nuclei changes in apoptotic cells and Western blot analysis of Bax, Bcl-2 to investigate the mechanisms by which curcumin protects cells from toxicity. Curcumin significantly improved the memory ability of AD mice in the step-through test, as indicated by the reduced number of step-through errors (P < 0.05) and prolonged step-through latency (P < 0.05). Curcumin also attenuated the neuropathological changes in the hippocampus and inhibited apoptosis accompanied by an increase in Bcl-2 level (P < 0.05), but the activity of Bax did not change (P > 0.05). AlCl(3) significantly reduced the viability of PC12 cells (P < 0.01). Curcumin increased cell viability in the presence of AlCl(3) (P < 0.01). The rate of apoptosis decreased significantly in the curcumin group (P < 0.05) when measured by flow cytometric analysis. Curcumin protected cells by increasing Bcl-2 level (P < 0.05), but the level of Bax did not change (P > 0.05). This study demonstrates that curcumin improves the memory ability of AD mice and inhibits apoptosis in cultured PC12 cells induced by AlCl(3). Its mechanism may involve enhancing the level of Bcl-2.
    Chinese medical journal 06/2008; 121(9):832-9. · 0.90 Impact Factor
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    ABSTRACT: To explore the effect and mechanisms of curcumin on learning and memory dysfunction induced by HIV-1 enveloped protein gp120. The SD rats were treated with gp120 by intracerebroventricular (ICV) infusion imitating the HIV-1 associated dementia (HAD) animal model. Subsequently, we applied the water maze test to evaluate the effect of gp120 on the learning and memory dysfunction in rats. The SD rats were divided into six groups: control group, sham group, model group, low dose curcumin group, middle dose curcumin group and high dose curcumin group. Except control and sham group, the others four groups received slowly 5 microL/d gp120 which dissolved in artificial cerebrospinal fluid (ACSF) for 3 days. Since the fourth day, the rats of low, middle, high dose curcumin groups were treated with 50 mg/(kg.d), 100 mg/(kg.d), 200 mg/(kg.d) curcumin, respectively. The others groups were treated with redistilled water. The treatment lasted for 14 days. Subsequently, the water maze test and NMDA2BR immunohistochemical staining were applied to evaluate the effect of curcumin on the rats. The rats were treated with gp120 50 ng/d by ICV infusion for 3 days can imitate the HAD animal model. The Morris water maze (MWM) test showed that the rats in model group had longer escape latencies compared with those in control group (P<0.05) and that rats in low, middle, high dose curcumin groups had shorter escape latencies compared with those in model group (P<0.05), and low dose curcumin group was better than the other two groups (P<0.05). Immunohistochemical staining showed that the expressions of NMDA2BR in model group decreased compared with the control groups (P<0.01), while the expressions of NMDA2BR in low, middle and high dose curcumin groups increased compared with the model groups. The SD rats were treated with gp120 by ICV infusion imitating the HAD animal model. The curcumin can improve the learning and memory dysfunction induced by gp120, the mechanism may be related to against the downregulation the expression of NMDA2BR.
    Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 04/2008; 24(4):328-31.
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    ABSTRACT: Although there is considerable evidence supporting that fever evolved as a host defense response, it is important that the rise in body temperature would not be too high. Many endogenous cryogens or antipyretics that limit the rise in body temperature have been identified. Endogenous antipyretics attenuate fever by influencing the thermoregulatory neurons in the preoptic anterior hypothalamus (POAH) and in adjacent septal areas including ventral septal area (VSA). Our previous study showed that intracerebroventricular (I.C.V.) injection of interleukin-1beta (IL-1beta) affected electrophysiological activities of thermosensitive neurons in VSA regions, and electrical stimulation of POAH reversed the effect of IL-1beta. To further investigate the functional electrophysiological connection between POAH and VSA and its mechanisms in thermoregulation, the firing rates of thermosensitive neurons in POAH of forty-seven unit discharge were recorded by using extracellular microelectrode technique in New Zealand white rabbits. Our results show that the firing rates of the warm-sensitive neurons decreased significantly and those of the cold-sensitive neurons increased in POAH when the pyrogen (IL-1beta) was injected I.C.V. The effects of IL-1beta on firing rates in thermosensitive neurons of POAH were reversed by electrical stimulation of VSA. An arginine vasopressin (AVP) V1 antagonist abolished the regulatory effects of VSA on the firing rates in thermosensitive neurons of POAH evoked by IL-1beta. However, an AVP V2 antagonist had no effects. These data indicated that VSA regulates the activities of the thermosensitive neurons of POAH through AVP V1 but not AVP V2 receptor.
    Life Sciences 02/2007; 80(5):408-13. · 2.56 Impact Factor
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    ABSTRACT: To study the antipyretic effect and mechanism of Daqingye injection (DQYI). The IL-1beta-induced febrile New Zealand rabbits were chosen as experimental models and the antipyretic effect of DQYI was observed. The expression of EP3 mRNA was investigated by using in situ hybridization (ISH) in POAH. First, the colonic temperature went up gradually after intravenous(i.v) IL-1beta. The peak value of temperature(deltaT) and thermal response index (TRI(1)) in IL-1beta-treated group were higher than those in control group (P<0.01). The DeltaT and TRI(1) of in DQYI and IL-1beta- treated group were lower than those in IL-1beta-treated group (P<0.05). The temperature of DQYI-treated group showed no distinguished difference compared with that in control group (P>0.05). Second, the expression of EP3 mRNA in the POAH of IL- 1beta-treated group increased markedly compared with that in control group (P<0.01). The expression of EP3 mRNA treated by IL-1beta+DQYI in the POAH decreased strikingly compared with that in IL-1beta group(P<0.05). DQYI has distinct antipyretic effect on IL-1beta-induced fever. The mechanism might be the inhibition of EP3 mRNA expression in POAH from rabbits.
    Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 02/2007; 23(1):42-5.
  • Jun Dong, Huangui Xiong
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    ABSTRACT: Human immunodeficiency virus type 1 (HIV-1) infection in its human host often results in progressive dementia and encephalopathy in adults and children, respectively. The mechanisms underlying virus-induced neurocognitive dysfunction are not fully understood. However, several studies strongly suggest that secretory viral and immune products from infected brain macrophages and microglia affect the onset and tempo of disease. One critical neurotoxin among these secretory products is the HIV-1 envelope glycoprotein gp120. To better understand how HIV-1 gp120 may affect cognitive function, we studied its effects on long-term potentiation (LTP) in the CA1 region of rat hippocampus, the brain region best linked to learning and memory. Although no effects were observed on basal synaptic transmission, HIV-1 gp120 inhibited LTP in a concentration-dependent manner in the presence of gamma-aminobutyric acid type A (GABAA) receptor antagonist. Heat-inactivated gp120 failed to block LTP. The HIV-1 gp120-mediated LTP inhibition was blocked by T140, a chemokine receptor CXCR4 antagonist, demonstrating gp120 inhibition of LTP via CXCR4. HIV-1 gp120 V3 loop peptides mimicked the inhibitory effects of HIV-1 gp120 protein on LTP. Monoclonal antibodies against the V3 loop epitope KRIHI eliminated the HIV-1 gp120 effects on LTP. These results further underscore the importance of HIV-1 gp120 in the pathogenesis of HIV-1-associated cognitive impairments seen during progressive viral infection.
    Journal of Neuroscience Research 03/2006; 83(3):489-96. · 2.97 Impact Factor
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    ABSTRACT: To explore the effect of platelet-activating factor on long-term potentiation in the CA1 region of rat hippocampal slices. We recorded the excitatory postsynaptic potentials (EPSPs) and investigated effect of long-term potentiation by PAF in rat hippocampus in vitro. Low doses (1 micromol/L ) of PAF could induce LTP, while higher doses (10-50 micromol/L) of PAF could inhibit induction of LTP. But it couldn't inhibit the LTP induced by subsequent high frequency stimulation and the EPSP of basal. GB of PAF receptor antagonists could prevent the LTP induced by low doses of PAF, and could't inhibit the LTP induced by HFS. Higher doses of PAF is an HIV-1-induced neurotoxin, it may contribute to the HAD pathogenesis by inhibition of LTP.
    Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 05/2005; 21(2):133-6.

Publication Stats

87 Citations
16.69 Total Impact Points

Institutions

  • 2006–2011
    • University of Nebraska Medical Center
      • Department of Pharmacology and Experimental Neuroscience
      Omaha, Nebraska, United States
    • University of Nebraska at Omaha
      • Department of Pharmacology and Experimental Neuroscience
      Omaha, NE, United States
  • 2008
    • University of Jinan (Jinan, China)
      Chi-nan-shih, Shandong Sheng, China
  • 2005–2008
    • Jinan University (Guangzhou, China)
      Shengcheng, Guangdong, China