minocycline and Encephalitis--Japanese

Japanese encephalitis (JE) is prevalent throughout eastern and southern Asia and the Pacific Rim. It is caused by the JE virus (JEV), which belongs to the family Flaviviridae. Despite the importance of JE, little is known about its pathogenesis. The role of oxidative stress in the pathogenesis of viral infections has led to increased interest in its role in JEV infections. This review focuses mainly on the role of oxidative stress in the pathogenesis of JEV infection and the antiviral effect of antioxidant agents in inhibiting JEV production. First, this review summarizes the pathogenesis of JE. The pathological changes include neuronal death, astrocyte activation, and microglial proliferation. Second, the relationship between oxidative stress and JEV infection is explored. JEV infection induces the generation of oxidants and exhausts the supply of antioxidants, which activates specific signaling pathways. Finally, the therapeutic efficacy of a variety of antioxidants as antiviral agents, including minocycline, arctigenin, fenofibrate, and curcumin, was studied. In conclusion, antioxidants are likely to be developed into antiviral agents for the treatment of JE.

Topics: Animals; Antioxidants; Antiviral Agents; Astrocytes; Cell Death; Curcumin; Encephalitis Virus, Japanese; Encephalitis, Japanese; Fenofibrate; Furans; Humans; Lignans; Microglia; Minocycline; Neurons; Oxidative Stress

Acute encephalitis syndrome (AES) is a public health problem in India. Neuroinfections are believed to be the most important etiology. Minocycline is a semisythetic tetracycline having excellent penetration into cerebrospinal fluid, established neuroprotective and antiviral properties besides action on nonviral causes of AES. It has been shown to be effective in animal model of Japanese encephalitis (JE). A randomized, controlled trial of nasogastric/oral minocycline in JE and AES at a single centre in Uttar Pradesh, northern India, was therefore conducted.. Patients beyond 3 years of age - but excluding women aged 16-44 years - hospitalized with AES of < =7 days duration were enrolled and block randomized to receive nasogastric/oral minocycline or placebo suspension and followed up. Patients, study personnel and those entering data were blinded as to drug or placebo received. Primary outcome was cumulative mortality at 3 months from hospitalization. Analysis was by intention to treat.. 281 patients were enrolled, 140 received drug and 141 placebo. While there was no overall statistically significant difference in 3 month mortality between drug and placebo groups [RR = 0 · 83 (0 · 6-1 · 1)], there were encouraging trends in patients older than 12 years [RR = 0.70 (0.41-1.18)] and in Glasgow Outcome Score (GOS) at 3 months (χ(2) = 7 · 44, p = 0 · 059). These trends were further accentuated if patients dying within one day of reaching hospital were excluded [OR for 3 month mortality =0 · 70 (0 · 46-1 · 07), p = 0.090; 3 month GOS p = 0 · 028].. A trend towards better outcomes was observed with minocycline, especially in those patients who survived the initial day in hospital. These findings should form the basis for planning a larger study and possibly including minocycline in the initial management of AES as seen here.. The trial was registered with Clinical Trials Registry of India (CTRI) - CTRI/2010/091/006143.

Topics: Acute Disease; Administration, Oral; Adolescent; Child; Child, Preschool; Encephalitis; Encephalitis, Japanese; Female; Hospital Mortality; Hospitals; Humans; India; Male; Minocycline; Syndrome

1. Minocycline, memantine,and glycoconjugate were assessed for their ability to protect cultured primary cortical neurons against double-stranded RNA-induced neurotoxicity. 2. Minocycline but not memantine or glycoconjugate protected cultured cells and warrants further investigation.

Topics: Analysis of Variance; Anti-Bacterial Agents; Apoptosis; Caspase 3; Cell Line, Tumor; Encephalitis, Japanese; Excitatory Amino Acid Antagonists; Glycoconjugates; Humans; L-Lactate Dehydrogenase; Memantine; Minocycline; Neurons; Neuroprotective Agents; Neurotoxicity Syndromes; RNA, Double-Stranded

Japanese encephalitis virus (JEV) induces neuroinflammation with typical features of viral encephalitis, including inflammatory cell infiltration, activation of microglia, and neuronal degeneration. The detrimental effects of inflammation on neurogenesis have been reported in various models of acute and chronic inflammation. We investigated whether JEV-induced inflammation has similar adverse effects on neurogenesis and whether those effects can be reversed using an anti-inflammatory compound minocycline.. Here, using in vitro studies and mouse models, we observed that an acute inflammatory milieu is created in the subventricular neurogenic niche following Japanese encephalitis (JE) and a resultant impairment in neurogenesis occurs, which can be reversed with minocycline treatment. Immunohistological studies showed that proliferating cells were replenished and the population of migrating neuroblasts was restored in the niche following minocycline treatment. In vitro, we checked for the efficacy of minocycline as an anti-inflammatory compound and cytokine bead array showed that production of cyto/chemokines decreased in JEV-activated BV2 cells. Furthermore, mouse neurospheres grown in the conditioned media from JEV-activated microglia exhibit arrest in both proliferation and differentiation of the spheres compared to conditioned media from control microglia. These effects were completely reversed when conditioned media from JEV-activated and minocycline treated microglia was used.. This study provides conclusive evidence that JEV-activated microglia and the resultant inflammatory molecules are anti-proliferative and anti-neurogenic for NSPCs growth and development, and therefore contribute to the viral neuropathogenesis. The role of minocycline in restoring neurogenesis may implicate enhanced neuronal repair and attenuation of the neuropsychiatric sequelae in JE survivors.

Topics: Animals; Brain; Cell Differentiation; Cell Lineage; Cell Movement; Cell Proliferation; Chemokines; Disease Models, Animal; Encephalitis Virus, Japanese; Encephalitis, Japanese; Inflammation; Inflammation Mediators; Mice; Microglia; Minocycline; Neural Stem Cells; Neurogenesis; Neurons; Solubility; Virion

Japanese encephalitis virus (JEV) is a neurotropic flavivirus that is the causative agent of a major mosquito-borne encephalitis in the world. Evasion of peripheral immune system facilitates the entry of the virus into the central nervous system (CNS) where it causes extensive neuronal inflammatory damage that leads to death or severe neuropschychiatric sequel in survivors. It has been proposed that after entry into the body, the virus is carried into the CNS by peripheral immune cells that act as Trojan horses. In this study we investigate whether macrophages can be considered as such a Trojan horse. We also investigate the role of minocycline, a synthetic tetracycline, in such processes. Minocycline has been found to be broadly protective in neurological disease models featuring inflammation and cell death but there has been no report of it having any modulatory role in peripheral macrophage-mediated immune response against viral infection. Persistence of internalized virus within macrophages was visualized by immunofluorescent staining. Cytotoxicity assay revealed that there was no significant cell death after 24 h and 72 h infection with JEV. Proinflammatory cytokine levels were elevated in cells that were infected with JEV but it was abrogated following minocycline treatment. Reactive oxygen species level was also increased after JEV infection. Nitric oxide level was found to increase after 72 h post infection but remained unchanged after 24h. The cellular levels of signaling molecules such as PI3 kinase, phophoAkt and phospho p38MAP kinase were found to be altered after JEV infection and minocycline treatment. JEV infection also affected the VEGF-MMP pathway. Increased activity of MMP-9 was detected from JEV-infected macrophage culture supernatants after 72 h; minocycline treatment resulted in reduced activity. Thus it seems that minocycline dampens peripheral immune reactions by decreasing proinflammatory cytokine release from infected macrophages and the virus survives within macrophages long enough to be carried into the CNS, even though minocycline inhibits cell survival.

Topics: Animals; Cells, Cultured; Cytokines; Encephalitis Virus, Japanese; Encephalitis, Japanese; Female; Immunologic Factors; Macrophages; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Minocycline; Nitric Oxide; Vascular Endothelial Growth Factor A; Virulence; Virus Internalization

Japanese encephalitis (JE) is caused by a neurotropic flavivirus that causes CNS damage that leads to death in acute cases or permanent neuropsychiatric sequel in survivors. The course of infection of this virus is not well defined though it is clear that it evades the host's innate immune response in the periphery. The current study was designed to investigate the time-dependent changes in the spleen and lymph node, apart from the CNS that are infected by the Japanese encephalitis virus (JEV). Our previous studies have led to the identification of minocycline, a semi-synthetic antibiotic, as a protective drug in JE. In this study we have also investigated the role of minocycline on the peripheral organs that are infected by JEV. Levels of IL-12 and MCP-1 in the organs were estimated by cytometric bead array, and immunohistochemical studies were performed on cryosections of tissue to detect CD3- or CD11b-positive cells as well as JEV antigen. We found that the levels of T cell-activating cytokine IL-12 and MCP-1 levels were significantly elevated in JEV-infected tissue samples in a time-dependent manner. Corresponding to this increase was the increase in the number of CD3- and CD11b-positive cells in the tissues of infected animals. Minocycline treatment abrogated these changes. Minocycline treatment also resulted in the gradual decrease in the number of CD11b (but not CD3) positive cells in the lymph node and spleen, even though the virus persisted in these organs. We also observed structural changes in the spleen following minocycline treatment.

Topics: Animals; Anti-Bacterial Agents; Brain; Chemokine CCL2; Disease Models, Animal; Encephalitis, Japanese; Immunohistochemistry; Interleukin-12; Lymph Nodes; Macrophages; Mice; Mice, Inbred BALB C; Minocycline; Spleen; T-Lymphocytes

Minocycline is neuroprotective in animal models of a number of acute CNS injuries, neurodegenerative diseases and CNS infection. While anti-inflammatory and anti-apoptotic effects of Minocycline have been characterized, the molecular basis for the neuroprotective effects of Minocycline remains unclear. We report here that Minocycline and two classical antioxidant compounds inhibit the Japanese Encephalitis Virus (JEV)-induced free radical generation in mouse neuroblastoma. In cultures of Neuro2a (N2a) cells infected with JEV for up to 24h, the number of cells undergoing cell death was also reduced by Minocycline (20 microM). JEV infection resulted in increased oxidative stress, as revealed by an increase in the fluorescence intensity for 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA), a reactive oxygen species (ROS) indicator. Minocycline at 20 microM inhibited this ROS production. Cells were moderately protected from JEV-induced death by diphenyleneiodonium (DPI), an inhibitor of flavon-containing enzyme inhibitor, whereas common antioxidants such as N-acetyl-cysteine (NAC) turned out to be ineffective. Direct antioxidant property of Minocycline and reference antioxidant compounds is evaluated by LDH assay, ROS measurement and mitochondrial membrane potential measurement. Our findings suggest that Minocycline reduces the neuronal damage seen in JEV infection in neuronal cell culture models at least in part through inhibition of oxidative stress.

Topics: Acetylcysteine; Animals; Anisotropy; Anti-Bacterial Agents; Antioxidants; Blotting, Western; Brain Neoplasms; Cell Death; Cell Line, Tumor; Encephalitis, Japanese; Enzyme Inhibitors; Free Radicals; In Situ Nick-End Labeling; L-Lactate Dehydrogenase; Membrane Fluidity; Membrane Potentials; Mice; Mice, Inbred BALB C; Minocycline; Mitochondrial Membranes; Neuroblastoma; Onium Compounds; Reactive Oxygen Species

The blood-brain barrier (BBB) serves to protect the central nervous system (CNS) from damage by exogenous molecules. Japanese encephalitis (JE), caused by a neurotropic flavivirus, leads to inflammation in the CNS, neuronal death and also compromises the structural and functional integrity of the BBB. Minocycline, a semisynthetic tetracycline, has been found to be broadly protective in neurological disease models featuring inflammation and cell death and at present, is being evaluated in clinical trials. In the present study, we propose that the neuroprotective role of minocycline in experimental models of JE extends also to the protection of the BBB. Damage to the BBB was assessed by Evan's blue dye exclusion test after minocycline treatment following Japanese encephalitis virus (JEV) infection. A breakdown of the BBB occurred in mice inoculated intravenously with JEV. This resulted in leakage of protein-bound Evan's blue dye into the brain tissue. Semi-quantitative RT-PCR revealed an up-regulation of chemokine receptors and adhesion molecules following JEV infection. Immunostaining showed leukocyte and neutrophil infiltration following JEV infection. Intraperitoneal injection of minocycline, beginning 24h post-JEV infection, abrogated the effects by reducing BBB damage, decreasing expression of iNOS, Cox-2, VEGF and also by reducing the elevated level of transcript of chemokine receptors and adhesion molecules in the brain. Matrix metalloproteinases (MMPs) are known to disrupt the BBB and minocycline was found to significantly decrease the activity of MMP-9 in brain tissue homogenates. Thus, minocycline, administered at a clinically relevant time, appears to maintain blood-brain barrier integrity following JEV infection.

Topics: Animals; Anti-Bacterial Agents; Blood-Brain Barrier; Cell Adhesion Molecules; Chemotaxis, Leukocyte; Coloring Agents; Cyclooxygenase 2; Disease Models, Animal; Encephalitis Virus, Japanese; Encephalitis, Japanese; Evans Blue; Female; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Minocycline; Neuroprotective Agents; Nitric Oxide Synthase Type II; Receptors, Chemokine; RNA, Messenger; Vascular Endothelial Growth Factor A

Minocycline is broadly protective in neurological disease models featuring inflammation and cell death and is being evaluated in clinical trials. Japanese encephalitis virus (JEV) is one of the most important causes of viral encephalitis worldwide. There is no specific treatment for Japanese encephalitis (JE) and no effective antiviral drugs have been discovered. Studies indicate that JE involves profound neuronal loss as well as secondary inflammation caused because of cell death. Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory and antiapoptotic effects that are completely separate from its antimicrobial action. Because tetracycline treatment is clinically well tolerated, we investigated whether minocycline protects against experimental model of JE. Intravenous inoculation of GP78 strain of JEV in adult mice results in lethal encephalitis and caused primarily because of neuronal death and secondary inflammation caused because of cell death. Minocycline confers complete protection in mice following JEV infection (p < 0.0001). Neuronal apoptosis, microglial activation, active caspase activity, proinflammatory mediators, and viral titer were markedly decreased in minocycline-treated JEV infected mice on ninth day post-infection. Treatment with minocycline may act directly on brain cells, because neuronal cell line Neuro2a were also salvaged from JEV-induced death. Our data suggest that minocycline may be a candidate to consider in human clinical trials for JE patients.

Topics: Animals; Antiviral Agents; Caspase 3; Caspase Inhibitors; Cell Line, Tumor; Cells, Cultured; Encephalitis Virus, Japanese; Encephalitis, Japanese; Enzyme Induction; Female; Male; Mice; Mice, Inbred BALB C; Microglia; Minocycline; Neuroprotective Agents; Protease Inhibitors; Swine; Virus Replication