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Functionally enhanced siRNA targeting TNF? attenuates DSS-induced colitis and TLR-mediated immunostimulation in mice.

ABSTRACT: Tumor necrosis factor (TNF?) is a proinflammatory cytokine involved in the pathogenesis of inflammatory bowel disease (IBD). Although TNF? has been extensively targeted using systemic drugs, the use of antisense and small interfering RNA (siRNA) to drive down its expression at the site of inflammation should provide important advantages. In this study, native and chemically modified siRNA against TNF? was developed and characterized using a murine model of IBD. siRNA with 2'-O-methyl and propanediol modifications (siTNF-OMe-P) were resistant to nuclease degradation and provided better silencing efficacy in vitro as compared to unmodified siRNA. Every modification reduced nonspecific Toll-like receptor (TLR)-mediated immunomodulation in human peripheral blood mononuclear cells (PBMC) cells. Intrarectal administration of siTNF-OMe-P significantly ameliorated the clinical endpoints and histopathological severity in 5% dextran sulphate sodium (DSS)-treated mice as compared to unmodified and other chemically modified siRNAs. Differential gene expression assessed in siTNF-OMe-P-treated animals correlated with improved colon integrity and reduced TLR activation as compared to all treatment groups. All in all, this study demonstrates that propanediol and 2'-O-methyl modifications have profound functional consequences for siRNA efficacy in vivo. Consequently, this strategy has potential implications for therapeutic intervention in IBD and other diseases.

SUBMITTER: Ocampo SM

PROVIDER: S-EPMC3277229 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Functionally enhanced siRNA targeting TNFα attenuates DSS-induced colitis and TLR-mediated immunostimulation in mice.

Ocampo Sandra M SM Romero Carolina C Aviñó Anna A Burgueño Joan J Gassull Miguel A MA Bermúdez Jordi J Eritja Ramon R Fernandez Ester E Perales Jose C JC

Molecular therapy : the journal of the American Society of Gene Therapy 20111101 2

Tumor necrosis factor (TNFα) is a proinflammatory cytokine involved in the pathogenesis of inflammatory bowel disease (IBD). Although TNFα has been extensively targeted using systemic drugs, the use of antisense and small interfering RNA (siRNA) to drive down its expression at the site of inflammation should provide important advantages. In this study, native and chemically modified siRNA against TNFα was developed and characterized using a murine model of IBD. siRNA with 2'-O-methyl and propane ...[more]

PMID: 22044934

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Project description:BackgroundColonic mucosal injuries are an important manifestation of ulcerative colitis (UC), which is related to hypoxia-induced glycolysis in colonic mucosal epithelial cells (cmECs). Panax notoginseng (PN) promotes the repair of colonic mucosal injuries by inhibiting hypoxia-induced glycolysis in cmECs; However, the mechanism by which this occurs is not completely clear. Here, we are to investigate the effects of PN on glucose metabolism in cmECs in colitis and the underlying mechanism.MethodsA model of dextran sulfate sodium-induced colitis rats was used in this research, and the severity of colitis was assessed by pathology, disease activity index (DAI), and weight changes. The content of intracellular pyruvate, intracellular lactate, adenosine triphosphate (ATP), reactive oxygen species (ROS), mitochondrial ROS (mtROS), myeloperoxidase (MPO) activity, superoxide dismutase (SOD) activity, and inflammatory cytokines was detected by assay kits. The expression levels of proteins were detected by western blotting. The expression levels of the ATP4a gene were detected by quantitative polymerase chain reaction (QT-PCR).ResultsThe colonic mucosal injuries of the colitis rats were significantly worse than those of the control group. Specifically, the hypoxia-induced glycolysis and potential of hydrogen (pH) in the colonic lumen were increased, and the expression of ATP4a was downregulated in the colitis rats. PN (1.0 g/kg) promoted the repair of colonic mucosal injuries, and reversed the pH in the colonic lumen. Further, PN increased the expression of ATP4a proteins, the content of ATP, and the SOD activity, and decreased the expression of pyruvate dehydrogenase lipoamide kinase isozyme and hypoxia-inducible factor 1-alpha proteins, the content of ROS, and MPO activity in cmECs in colitis. PN also increased the expression of ATP4a, cytochrome P450 family 21 subfamily a member 2, and hydroxy-delta-5-steroid dehydrogenase, 3 beta and steroid delta-isomerase 2 proteins in the mitochondria, and decreased the content of mtROS in cmECs.ConclusionsPN alleviated the pH in the colonic lumen and hypoxia-induced glycolysis in cmECs by reducing the hypoxia-induced glycolysis caused by the downregulation of ATP4a protein, thereby promoting the repair of colonic mucosal injuries in colitis.

Project description:Ulcerative colitis (UC) is a form of inflammatory bowel disease, which manifests as irritation or swelling and sores in the large intestine in a relapsing and remitting manner. In a dextran sulfate sodium sulfate (DSS)-induced UC model in female mice, we found that the levels of cyclic guanosine monophosphate (cGMP) are reduced, while the expression of phosphodiesterase 9A (PDE9A) is highest among all phosphodiesterase (PDEs). Since PDE9 has the highest affinity toward cGMP, we evaluated the selective PDE9 inhibitor PF-04447943 (PF) as a potential candidate for UC treatment. PF has been extensively studies in cognitive function and in sickle cell disease, but not in models for inflammatory bowel disease (IBD). Therefore, we used female C57BL/6 mice treated with 3% DSS alone or co-treated with PF or sulfasalazine (SASP) to study the body weight, colon length, histopathology, and measure superoxide dismutase (SOD), malondialdehyde (MDA), and cGMP level, as well as cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), interleukin-12/23 (IL-12/23), interleukin-10 (IL-10), and pathways including nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), and inflammasome activation. In addition, the number of dendritic cells (DC) and regulatory T cells (Treg cell) was assessed in the spleen, lymph node, and colon using flow cytometry. DSS reduced the number of goblet cells, decreased colon lengths and body weights, all of them were attenuated by PF treatment. It also suppressed the elevated level of inflammatory cytokines and increased level the anti-inflammatory cytokine, IL-10. PF treatment also reduced the DSS-induced inflammation by suppressing oxidative stress, NF-κB, STAT3, and inflammasome activation, by upregulating nuclear factor erythroid 2-related factor 2 (Nrf-2) and its downstream proteins via extracellular signal-regulated kinase (ERK) phosphorylation. Importantly, PF reversed imbalance in Treg/T helper 17 cells (Th17) cells ratio, possibly by regulating dendritic cells and Treg developmental process. In summary, this study shows the protective effect of a PDE9A inhibitor in ulcerative colitis by suppressing oxidative stress and inflammation as well as reversing the Treg/Th17 cells imbalance.

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Functionally enhanced siRNA targeting TNF? attenuates DSS-induced colitis and TLR-mediated immunostimulation in mice.

Publications

Functionally enhanced siRNA targeting TNFα attenuates DSS-induced colitis and TLR-mediated immunostimulation in mice.

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