Enhancing innate antiviral immune responses in rainbow trout by double stranded RNA delivered with cationic phytoglycogen nanoparticles

Abstract

Innate immunity is induced when pathogen-associated molecular patterns (PAMPs) bind host pattern recognition receptors (PRRs). Polyinosinic:polycytidylic acid [poly(I:C)] is a synthetic analogue of viral dsRNA that acts as a PAMP, inducing type I interferons (IFNs) in vertebrates. In the present study, the immunostimulatory effects of high molecular weight (HMW) poly(I:C) in rainbow trout cells were measured when bound to a cationic phytoglycogen nanoparticle (Nano-HMW). The physical characteristics of the nanoparticle itself, when bound to different lengths of dsRNA and when cell associated was evaluated. Optimal concentration and timing for innate immune stimulation was measured using the RTG-P1 reporter cell line. The immunostimulatory effects of HMW poly (I:C) was compared to Nano-HMW in vitro using the RTgutGC cell line cultured in a conventional monolayer or a transwell culture system. The ability of an activated intestinal epithelium to transmit an antiviral signal to macrophages was evaluated using a co-culture of RTgutGC cells and RTSll (a monocyte/macrophage cell). In all culture conditions, Nano-HMW was a more effective inducer of IFN-related antiviral immune responses compared to HMW poly (I:C) alone. This study introduces the use of cationic phytoglycogen nanoparticles as a novel delivery system for immunomodulatory molecules to enhance immune responses in aquatic vertebrates.

Phytoglycogen Nanoparticle Delivery System for Inorganic Selenium Reduces Cytotoxicity without Impairing Selenium Bioavailability

“…Cationic PhG NPs prepared as previously described were used to bind inorganic selenium derivatives. 29 To form SeNP-Ionic, 2.5 g Na Sel (Na 2 SeO 3 ; Sigma Aldrich) and 2.5 g cationic PhG NPs were mixed in 50 mL deionized water, stirred overnight, dialyzed, and lyophilized. To form SeNP-Covalent, 15 mg LiCl and 1.5 mL N,N-dimethylacetamide (DMAc) were added to 84.3 mg PhG NPs in a conical Wheaton vial equipped with a triangular stir bar.…”

“… 31 The prepared SeNP (SeNP-Ionic or SeNP-Covalent) were further characterized for particle size using previously described methods. 29

Figure 1 Illustration of the synthesis of the two selenium formulations. Na 2 SeO 3 was bound by electrostatic interaction to PhG NPs (ionic formulation).

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“…31 The prepared SeNP (SeNP-Ionic or SeNP-Covalent) were further characterized for particle size using previously described methods. 29…”

“… 27 PhG NPs have been used in a previous study for efficient delivery of RNA molecules into fish cells. 29 The present study tested whether this biodegradable nanoparticle delivery method for inorganic selenium reduced selenium-mediated cytotoxicity without impairing bioavailability, thus allowing a higher tolerable intake level of selenium; a desirable feature when supplementing diets. Thus, the effects of SeNPs (SeNP-Ionic or SeNP-Covalent) were evaluated in intestinal cells of economically important farmed animals like rainbow trout and in cells derived from bovine species.…”

Ultrasound-Responsive Materials for Drug/Gene Delivery

“…Advanced drug delivery systems (DDS) require a demand of dosage, spatial, and temporal control strategy (Liu et al, 2016b). Several studies have shown that microspheres and nanoparticles can protect drugs or genes and further improve therapeutic outcomes (Nakamura and Harashima, 2017;Alkie et al, 2019;Holley et al, 2019;Yu et al, 2019). However, the uncontrolled release of drugs and genes at the disease site is the main limitation of microspheres and nanoparticles.…”