Targeted Delivery of Small Interfering RNA to Human Dendritic Cells To Suppress Dengue Virus Infection and Associated Proinflammatory Cytokine Production

Abstract

Dengue is a common arthropod-borne flaviviral infection in the tropics, for which there is no vaccine or specific antiviral drug. The infection is often associated with serious complications such as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), in which both viral and host factors have been implicated. RNA interference (RNAi) is a potent antiviral strategy and a potential therapeutic option for dengue if a feasible strategy can be developed for delivery of small interfering RNA (siRNA) to dendritic cells (DCs) and macrophages, the major in vivo targets of the virus and also the source of proinflammatory cytokines. Here we show that a dendritic cell-targeting 12-mer peptide ( Dengue is a mosquito-borne flavivirus infection that has emerged as a serious public health problem worldwide. Four serotypes of dengue virus (DEN-1 to DEN-4) are capable of causing human disease varying in severity from acute selflimiting febrile illness to life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The plasma leakage, hemorrhagic manifestations, and shock that characterize DHF/DSS are considered to have an immunological basis, as they are more common during secondary infection with a heterologous dengue virus strain (15,28,33). However, severe clinical manifestations can also occur during primary dengue infection, pointing to a contributory role of viral virulence factors. The WHO estimates that more than 20,000 people worldwide, mainly children, die each year from serious complications of dengue. No specific antiviral therapies are currently available for treating the infection, and efforts to develop a safe prophylactic vaccine have been hindered by the complex role of the immune system in disease pathogenesis (39,52,57). Thus, novel treatment strategies that block viral replication and/or to attenuate the exaggerated cytokine response associated with DHF/DSS complications are urgently needed.Potent and specific gene silencing mediated by RNA interference (RNAi) has generated a great deal of interest in development of RNAi as a therapeutic strategy against viral infections (50,54). Many studies have demonstrated the effectiveness of the RNAi approach to suppress flavivirus infection, including dengue virus replication in experimental cell lines (3,23,26,42,60). In addition, the versatility of RNAi could also be exploited to block important host mediators that contribute to dengue pathogenesis. However, the existence of * Corresponding author. Present address:

Special delivery: targeted therapy with small RNAs

“…These complexes also suppress TNF-a production induced by innate immune stimulation of dendritic cells in vivo. 55 Targeted nanoparticles. Nanoparticles carrying siRNAs have also been used to induce functional silencing in subcutaneously transplanted tumors in nude mice.…”

Functional RNA Delivery Targeted to Dendritic Cells By Synthetic Nanoparticles

“…The amphipathic peptide Endo-Porter forms stable complexes with siRNA and was also successfully delivered to macrophages in glucan shells [92]. A cationic nona-d-arginine construct was applied together with a DC-targeting ligand to deliver siRNA for knockdown of dengue virus replication in macrophages and DCs [93]. Lipid-based nanoparticles modified with an octa-arginine peptide and the pH-sensitive fusiogenic GALA peptide promoted cytosolic delivery of siRNA; this targeted mRNA encoding the SOCS1 protein, the synthesis of which was successfully knocked down in mouse DCs [94].…”

RNA Interference-Based Therapeutics: Harnessing the Powers of Nature

“…Sereval R&D programs are currently focusing their efforts on infection diseases, HIV is one of these examples. Introduction of synthetic siRNA into cells or its stable endogenous production using vector-driven shRNA have been shown to suppress HIV replication in vitro and, in some instances, in vivo (Subramanya et al, 2010). RNAi can specifically degrade the HIV-1 genome in infected T cells very early in the viral replication cycle.…”