MicroRNAs (miRNAs) are single-stranded small RNA molecules that regulate various cellular processes. miRNA 155 (miR-155) regulates various aspects of innate and adaptive immune responses and plays a key role in various viral infections and the resulting neuroinflammation. The present study evaluated the involvement of miR-155 in modulating Japanese encephalitis virus (JEV)-induced neuroinflammation. We observed that miR-155 expression was upregulated during JEV infection of mouse primary microglia, the BV-2 microglia cell line, and in both mouse and human brains. In vitro and in vivo knockdown of miR-155 minimized JEV-induced inflammatory responses. In the present study, we confirmed targeting of the Src homology 2-containing inositol phosphatase 1 (SHIP1) 3= untranslated region (UTR) by miR-155 in the context of JEV infection. Inhibition of SHIP1 by miR-155 resulted in higher beta interferon (IFN-␤) and proinflammatory cytokine production through activation of TANKbinding kinase 1 (TBK-1). Based on these observations, we conclude that miR-155 modulates the neuroinflammatory response during JEV infection via negative regulation of SHIP1 expression. Thus, modulation of miR-155 could be a novel strategy to regulate JEV-induced neuroinflammation. IMPORTANCE Japanese encephalitis virus (JEV), a member of the family Flaviviridae that causes Japanese encephalitis (JE), is the most common mosquito-borne encephalitis virus in the Japanese encephalitis virus (JEV), a member of the family Flaviviridae, is a single-stranded, positive-sense RNA virus that causes Japanese encephalitis (JE) (1, 2). JE is endemic in most Southeast Asian countries (3, 4). The availability of an effective vaccine and an active immunization program have resulted in a reduced number of JE cases in a few countries (5). The early clinical features of JE include fever, headache, and vomiting. Two weeks after JEV infection, patients develop neurological symptoms, like seizure, tremor, photophobia, and movement disorder (6). These clinical features are not exclusive to JEV infection, and hence, laboratory diagnosis is needed to differentiate it from other neurological disorders. Detection of anti-JEV IgM antibodies in the cerebrospinal fluid (CSF) and serum is frequently used to diagnose JE (7). The fatality rate of JEV infection is ϳ25%. A majority of survivors (ϳ50%) have neuropsychiatric sequelae; only ϳ25% recover completely (8). Hence, JEV poses major health concerns and economic burdens in the Asia-Pacific region. During the last decade, we and others have made significant progress in the understanding molecular mechanisms involved in JEV infection.MicroRNAs (miRNAs) are small, noncoding RNAs ϳ19 to 22 nucleotides in length that regulate various cellular processes by binding to the 3= untranslated region (UTR) of target proteins, resulting in either degradation of RNA or translational suppression (9, 10). Our knowledge of the role of miRNAs in various diseases is expanding rapidly. Various reports support the role of miRNAs in neuroviral...

Japanese encephalitis virus (JEV), a single-stranded RNA (ssRNA) virus, is the leading cause of encephalitis in Asia. Microglial activation is one of the key events in JEV-induced neuroinflammation. Although the various microRNAs (miRNAs) has been shown to regulate microglia activation during pathological conditions including neuroviral infections, till date, the involvement of miRNAs in JEV infection has not been evaluated. Hence, we sought to evaluate the possible role of miRNAs in mediating JEV-induced microglia activation. Initial screening revealed significant up-regulation of miR-29b in JEV-infected mouse microglial cell line (BV-2) and primary microglial cells. Furthermore, using bioinformatics tools, we identified tumor necrosis factor alpha-induced protein 3, a negative regulator of nuclear factor-kappa B signaling as a potential target of miR-29b. Interestingly, in vitro knockdown of miR-29b resulted in significant overexpression of tumor necrosis factor alpha-induced protein 3, and subsequent decrease in nuclear translocation of pNFjB. JEV infection in BV-2 cell line elevated inducible nitric oxide synthase, cyclooxygenase-2, and pro-inflammatory cytokine expression levels, which diminished after miR-29b knockdown. Collectively, our study demonstrates involvement of miR-29b in regulating JEV-induced microglial activation.

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Nuclear factor-erythroid 2 related factor 2 (Nrf2)-mediated signaling plays a central role in maintaining cellular redox homeostasis of hepatic cells. Carbon monoxide releasing molecule-A1 (CORM-A1) has been reported to stimulate up-regulation and nuclear translocation of Nrf2 in hepatocytes. However, the role of CORM-A1 in improving lipid metabolism, antioxidant signaling and mitochondrial functions in nonalcoholic steatohepatitis (NASH) is unknown. In this study, we report that CORM-A1 prevents hepatic steatosis in high fat high fructose (HFHF) diet fed C57BL/6J mice, used as model of NASH. The beneficial effects of CORM-A1 in HFHF fed mice was associated with improved lipid homeostasis, Nrf2 activation, upregulation of antioxidant responsive (ARE) genes and increased ATP production. As, mitochondria are intracellular source of reactive oxygen species (ROS) and important sites of lipid metabolism, we further investigated the mechanisms of action of CORM-A1-mediated improvement in mitochondrial function in palmitic acid (PA) treated HepG2 cells. Cellular oxidative stress and cell viability were found to be improved in PA + CORM-A1 treated cells via Nrf2 translocation and activation of cytoprotective genes. Furthermore, in PA treated cells, CORM-A1 improved mitochondrial oxidative stress, membrane potential and rescued mitochondrial biogenesis thru upregulation of Drp1, TFAM, PGC-1α and NRF-1 genes. CORM-A1 treatment improved cellular status by lowering glycolytic respiration and maximizing OCR. Improvement in mitochondrial respiration and increment in ATP production in PA + CORM-A1 treated cells further corroborate our findings. In summary, our data demonstrate for the first time that CORM-A1 ameliorates tissue damage in steatotic liver via Nrf2 activation and improved mitochondrial function, thus, suggesting the anti-NASH potential of CORM-A1.

MicroRNAs (miRNAs) are single-stranded noncoding regions of approximately 21 nucleotides that regulate protein synthesis by targeting mRNAs for translational repression or degradation at the post-transcriptional level. These classes of RNAs are highly conserved across species and are known to regulate several protein-coding genes in humans. Therefore, their dysregulation is synonymous with inflammation, autoimmunity, neurodegeneration, viral infections, heart diseases, and cancer, among other conditions. Recent years have witnessed considerable amount of research interest in studies on miRNA-mediated modulation of gene function during neuroinflammation. This review is a meticulous compilation of information on biogenesis of miRNAs and their role in neuroinflammatory diseases. Further, their potential as markers of inflammatory diseases or novel therapeutic agents against neuroinflammation has also been discussed in detail.

The immunosuppressive tumor microenvironment usurps host antitumor immunity by multiple mechanisms including interference with the Notch system, which is important for various metazoan cell fate decisions and hematopoietic cell differentiation and function. We observed that treatment with the proteasome inhibitor bortezomib in mice bearing various solid tumors resulted in an upregulated expression of various Notch signaling components in lymphoid tissues, thereby increasing CD8+T-lymphocyte IFNγ secretion and expression of effector molecules, perforin and granzyme B, as well as the T-box transcription factor eomesodermin. Bortezomib also neutralized TGFβ-mediated suppression of IFNγ and granzyme B expression in activated CD8+T-cells. Of note, bortezomib reversed tumor-induced downregulation of Notch receptors, Notch1 and Notch2, as well as increased the levels of cleaved Notch intracellular domain (NICD) and downstream targets Hes1 and Hey1 in tumor-draining CD8+T-cells. Moreover, bortezomib promoted CD8+T-cell nuclear factor-κB (NFκB) activity by increasing the total and phosphorylated levels of the IκB kinase and IκBα as well as the cytoplasmic and nuclear levels of phosphorylated p65. Even when we blocked NFκB activity by Bay-11-7082, or NICD cleavage by γ-secretase inhibitor, bortezomib significantly increased expression of Notch Hes1 and Hey1 genes as well as perforin, granzyme B and eomesodermin in activated CD8+T-cells. Data suggest that bortezomib can rescue tumor-induced dysfunction of CD8+T-cells by its intrinsic stimulatory effects promoting NICD-NFκB crosstalk. These findings provide novel insights on using bortezomib not only as an agent to sensitize tumors to cell death but also to provide lymphocyte-stimulatory effects, thereby overcoming immunosuppressive actions of tumor on anti-tumor T-cell functions.

Bortezomib is an inhibitor of the ubiquitin-proteasome proteolytic pathway responsible for intracellular protein turnover. Cellular proteins controlled by this pathway represent a diverse group of potential therapeutic targets, particularly in cancer cells, which exploit this proteasomal pathway to promote their growth and diminish apoptosis. Along with inhibiting the proteasome and thus sensitizing tumor cells to apoptosis, bortezomib may also have multiple effects on the host immune responses. This review summarizes the effects that bortezomib may play on immune cell subsets in various disease states in modifying lymphocyte receptors, ligands, the expression of various cytokines and chemokines and their downstream signaling. We also propose steps that can be taken to refine combinatorial strategies that include bortezomib to improve current immunotherapeutic approaches.