Sequence-Specific Modifications Enhance the Broad-Spectrum Antiviral Response Activated by RIG-I Agonists.

Unlabelled: The cytosolic RIG-I (retinoic acid-inducible gene I) receptor plays a pivotal role in the initiation of the immune response against RNA virus infection by recognizing short 5'-triphosphate (5'ppp)-containing viral RNA and activating the host antiviral innate response. In the present study, we generated novel 5'ppp RIG-I agonists of varieous lengths, structures, and sequences and evaluated the generation of the antiviral and inflammatory responses in human epithelial A549 cells, human innate immune primary cells, and murine models of influenza and chikungunya viral pathogenesis. A 99-nucleotide, uridine-rich hairpin 5'pppRNA termed M8 stimulated an extensive and robust interferon response compared to other modified 5'pppRNA structures, RIG-I aptamers, or poly(I·C).

Nucleotide receptors control IL-8/CXCL8 and MCP-1/CCL2 secretions as well as proliferation in human glioma cells.

Glioma cells release cytokines to stimulate inflammation that facilitates cell proliferation. Here, we show that Lipopolysaccharide (LPS) treatment could induce glioma cells to proliferate and this process was dependent on nucleotide receptor activation as well as interleukin-8 (IL-8/CXCL8) secretion. We observed that extracellular nucleotides controlled IL-8/CXCL8 and monocyte chemoattractant protein 1 (MCP-1/CCL2) release by U251MG and U87MG human glioma cell lines via P2X7 and P2Y6 receptor activation.

Triptolide-mediated inhibition of interferon signaling enhances vesicular stomatitis virus-based oncolysis.

Preclinical and clinical trials demonstrated that use of oncolytic viruses (OVs) is a promising new therapeutic approach to treat multiple types of cancer. To further improve their viral oncolysis, experimental strategies are now combining OVs with different cytotoxic compounds. In this study, we investigated the capacity of triptolide - a natural anticancer molecule - to enhance vesicular stomatitis virus (VSV) oncolysis in OV-resistant cancer cells.

BCL-2 inhibitors sensitize therapy-resistant chronic lymphocytic leukemia cells to VSV oncolysis.

Many primary cancers including chronic lymphocytic leukemia (CLL) are resistant to vesicular stomatitis virus (VSV)-induced oncolysis due to overexpression of the antiapoptotic and antiautophagic members of the B-cell lymphoma-2 (BCL-2) family. In the present study, we investigated the mechanisms of CLL cell death induced as a consequence of VSV infection in the presence of BCL-2 inhibitors, obatoclax, and ABT-737 in primary ex vivo CLL patient samples. Microarray analysis of primary CD19⁺ CD5⁺ CLL cells treated with obatoclax and VSV revealed changes in expression of genes regulating apoptosis, the mechanistic target of rapamycin (mTOR) pathway, and cellular metabolism.

NTPDase1 controls IL-8 production by human neutrophils.

The ectonucleotidase NTPDase1 (CD39) terminates P2 receptor activation by the hydrolysis of extracellular nucleotides (i.e., the P2 receptor ligands).

Endothelial P2Y2 receptor regulates LPS-induced neutrophil transendothelial migration in vitro.

Previous studies showed that P2 receptors are involved in neutrophil migration via stimulation of chemokine release and by facilitating chemoattractant gradient sensing. Here, we have investigated whether these receptors are involved in LPS-induced neutrophil transendothelial migration (TEM) using a Boyden chamber where neutrophils migrated through a layer of lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs). In line with a role of P2 receptors, neutrophil TEM was inhibited by the P2 receptor antagonists suramin and reactive blue 2 (RB-2) acting on the basolateral, but not luminal, HUVECs' P2 receptors.

The P2 receptor antagonist PPADS abrogates LPS-induced neutrophil migration in the murine air pouch via inhibition of MIP-2 and KC production.

In this work, we show that P2 nucleotide receptors control lipopolysaccharide (LPS)-induced neutrophil migration in the mouse air pouch model. Neutrophil infiltration in LPS-treated air pouches was reduced by the intravenous (iv) administration of the non-selective P2 receptor antagonist PPADS but not by suramin and RB-2. In addition, the iv administration of a P2 receptor ligand, UTP, enhanced LPS-induced neutrophil migration.

Concomitant activation of P2Y(2) and P2Y(6) receptors on monocytes is required for TLR1/2-induced neutrophil migration by regulating IL-8 secretion.

Extracellular nucleotides regulate a variety of cellular responses involved in inflammation via the activation of P2 receptors. Here, we show that nucleotides regulate TLR2-induced neutrophil migration both in vivo and in vitro. The nucleotide scavenger apyrase inhibited neutrophil recruitment in murine air pouches injected with the TLR2 agonist Pam(3)CSK(4).

Extracellular ATP and P2 receptors are required for IL-8 to induce neutrophil migration.

The chemokine interleukin 8 (IL-8) is a major chemoattractant for human neutrophils. Here, we demonstrate novel evidence that IL-8-induced neutrophil chemotaxis requires a concurrent activation of P2 receptors, most likely the P2Y(2) which is dominantly expressed in these cells. Indeed, the migration of human neutrophils towards IL-8 was significantly inhibited by the P2Y receptor antagonists, suramin and reactive blue 2 (RB-2) and potentiated by a P2Y(2) ligand, ATP, but insensitive to specific antagonists of P2Y(1), P2Y(6) and P2Y(11) receptors.

Extracellular nucleotides mediate LPS-induced neutrophil migration in vitro and in vivo.

Extracellular nucleotides are emerging as important inflammatory mediators. Here, we demonstrate that these molecules mediate LPS-induced neutrophil migration in vitro and in vivo. Apyrase, a nucleotide scavenger, reduced the ability of LPS-stimulated monocytes to recruit neutrophils, as assayed using a modified Boyden chamber.

Humoral immune response elicited by plasmid DNA containing HGV E2 gene fragment.

In order to study the feasibility of E2 gene fragment of hepatitis virus G(HGV) as a component of DNA vaccine against the hepatitis virus G infection, a 559bp DNA fragment encoding HGV E2 was cloned into plasmid pCMV-S from pThioHis-E2 in the same reading frame with HBsAg gene to form a recombinant plasmid named pCMV-S-E2. BALB/c mice of Kunming strain were immunized with purified plasmid DNA of pCMV-S-E2 by intra-muscularly inoculation. The immunizations were boosted twice at an interval of 14 days.