Dina Aggad

The Two Groups of Zebrafish Virus-Induced Interferons Signal via Distinct Receptors with Specific and Shared Chains

Because the availability of fish genomic data, the number of reported sequences for fish type II helical cytokines is rapidly growing, featuring different IFNs including virus-induced IFNs (IFNφ) and IFN-γ, and IL-10 with its related cytokines (IL-20, IL-22, and IL-26). Many candidate receptors exist for these cytokines and various authors have postulated which receptor chain would be involved in which functional receptor in fish. To date, only the receptor for zebrafish IFNφ1 has been identified functionally. Three genes encoding virus-induced IFNφs have been reported in zebrafish. In addition to these genes clustered on chromosome 3, we have identified a fourth IFNφ gene on chromosome 12. All these genes possess the intron-exon organization of mammalian λ IFNs. In the zebrafish larva, all induce the expression of reporter antiviral genes; protection in a viral challenge assay was observed for IFNφ1 and IFNφ2. Using a combination of gain- and loss-of-function experiments, we also show that all zebrafish IFNφs do not bind to the same receptor. Two subgroups of fish virus-induced IFNs have been defined based on conserved cysteines, and we find that this subdivision correlates with receptor usage. Both receptor complexes include a common short chain receptor (CRFB5) and a specific long chain receptor (CRFB1 or CRFB2).

In Vivo Analysis of Ifn-γ1 and Ifn-γ2 Signaling in Zebrafish

The zebrafish genome contains a large number of genes encoding potential cytokine receptor genes as judged by homology to mammalian receptors. The sequences are too divergent to allow unambiguous assignments of all receptors to specific cytokines, and only a few have been assigned functions by functional studies. Among receptors for class II helical cytokines—i.e., IFNs that include virus-induced Ifns (Ifn-ϕ) and type II Ifns (Ifn-γ), together with Il-10 and its related cytokines (Il-20, Il-22, and Il-26)—only the Ifn-ϕ–specific complexes have been functionally identified, whereas the receptors for the two Ifn-γ (Ifn-γ1 and Ifn-γ2) are unknown. In this work, we identify conditions in which Ifn-γ1 and Ifn-γ2 (also called IFNG or IFN-γ and IFN-gammarel) are induced in fish larvae and adults. We use morpholino-mediated loss-of-function analysis to screen candidate receptors and identify the components of their receptor complexes. We find that Ifn-γ1 and Ifn-γ2 bind to different receptor complexes. The receptor complex for Ifn-γ2 includes cytokine receptor family B (Crfb)6 together with Crfb13 and Crfb17, whereas the receptor complex for Ifn-γ1 does not include Crfb6 or Crfb13 but includes Crfb17. We also show that of the two Jak2 paralogues present in the zebrafish Jak2a but not Jak2b is involved in the intracellular transmission of the Ifn-γ signal. These results shed new light on the evolution of the Ifn-γ signaling in fish and tetrapods and contribute toward an integrated view of the innate immune regulation in vertebrates.

Nanodiamond–PMO for two-photon PDT and drug delivery

In this article, we highlight the properties of nanodiamonds (ND), which were encapsulated in periodic mesoporous organosilica nanoparticles (PMO) and were able to generate reactive oxygen species for photodynamic applications upon two-photon excitation (TPE). The ND@PMO nanoparticles were characterized by various techniques and were then loaded with the anti-cancer drug doxorubicin. The release of the drug was pH sensitive and a synergistic cancer cell killing effect was observed when cancer cells were incubated with doxorubicin-loaded ND@PMO and irradiated with two-photon excitation at 800 nm.

Mesoporous silicon nanoparticles for targeted two-photon theranostics of prostate cancer

A novel non-toxic porous silicon nanoparticle grafted with a mannose-6-phosphate analogue and applicable in 2-photon imaging and photodynamic therapy was specifically designed for targeting prostate cancer cells.

Fluorescent periodic mesoporous organosilica nanoparticles dual-functionalized via click chemistry for two-photon photodynamic therapy in cells

The synthesis of ethenylene-based periodic mesoporous organosilica nanoparticles for two-photon imaging and photodynamic therapy of breast cancer cells is described. A dedicated two-photon absorbing fluorophore possessing four triethoxysilyl groups and having large two-photon absorption in the near IR region, and azidopropyltriethoxysilane were incorporated into the structure. The mesoporous nanoparticles of 100 nm diameter were further functionalized by means of click chemistry with a propargylated fluorescent bromo-quinoline photosensitizer able to generate singlet oxygen. The photophysical properties and two-photon absorption properties of the nanoparticles were investigated evidencing complementary contribution of the two dyes. Both dyes contribute to the two-photon absorption response of the mesoporous nanoparticles while efficient FRET from the two-photon fluorophore to the quinoline sensitizer is observed. The dual-functionalized nanoparticles were incubated with MCF-7 breast cancer cells. Two-photon confocal imaging demonstrated the endocytosis of the nanoparticles within cancer cells. Moreover, brief two-photon irradiation (3 scans of 1.57 s) at 760 nm at high laser power (3 W) was shown to induce 40% of cancer cell death demonstrating the potential of the dual-functionalized mesoporous organosilica nanoparticles for two-photon photodynamic therapy.

PEGylation rate influences peptide-based nanoparticles mediated siRNA delivery in vitro and in vivo

Abstract Small interfering RNAs (siRNAs) present a strong therapeutic potential because of their ability to inhibit the expression of any desired protein. Recently, we developed the retro‐inverso amphipathic RICK peptide as novel non‐covalent siRNA carrier. This peptide is able to form nanoparticles (NPs) by self‐assembling with the siRNA resulting in the fully siRNA protection based on its protease resistant peptide sequence. With regard to an in vivo application, we investigated here the influence of the polyethylene glycol (PEG) grafting to RICK NPs on their in vitro and in vivo siRNA delivery properties. A detailed structural study shows that PEGylation did not alter the NP formation (only decrease in zeta potential) regardless of the used PEGylation rates. Compared to the native RICK:siRNA NPs, low PEGylation rates (≤ 20%) of the NPs did not influence their cellular internalization capacity as well as their knock‐down specificity (over‐expressed or endogenous system) in vitro. Because the behavior of PEGylated NPs could differ in their in vivo application, we analyzed the repartition of fluorescent labeled NPs injected at the one‐cell stage in zebrafish embryos as well as their pharmacokinetic (PK) profile after administration to mice. After an intra‐cardiac injection of the PEGylated NPs, we could clearly determine that 20% PEG‐RICK NPs reduce significantly liver and kidney accumulation. NPs with 20% PEGylation constitutes a modular, easy‐to‐handle drug delivery system which could be adapted to other types of functional moieties to develop safe and biocompatible delivery systems for the clinical application of RNAi‐based cancer therapeutics. Graphical abstract Figure. No Caption available.

Porphyrins Conjugated with Peripheral Thiolato Gold(I) Complexes for Enhanced Photodynamic Therapy

Porphyrins fused to imidazolium salts across two neighboring β-pyrrolic positions were used as N-heterocyclic carbene (NHC) precursors to anchor AuI -Cl complexes at their periphery. Synthesis of several thiolato-AuI complexes was then achieved by substituting chloride for thiolates. Photodynamic properties of these complexes were investigated: the data obtained show that the Au-S bonds could be cleaved upon irradiation. The proposed mechanism to explain the release of thiolate moiety involves the S atom oxidation by singlet oxygen generated in the course of irradiation. In view of photodynamic therapy (PDT) applications, these porphyrins fused to NHC-AuI complexes were tested as photosensitizers to kill MCF-7 breast cancer cells. Results show the important role played by the ancillary ligands (chloride versus thiolates) on the photodynamic effect.

Degradable gold core–mesoporous organosilica shell nanoparticles for two-photon imaging and gemcitabine monophosphate delivery

The synthesis of degradable gold core–mesoporous organosilica shell nanoparticles is described. The nanoparticles were very efficient for two-photon luminescence imaging of cancer cells and for in vitro gemcitabine monophosphate delivery, allowing promising theranostic applications in the nanomedicine field.

Biocompatible Periodic Mesoporous Ionosilica Nanoparticles with Ammonium Walls: Application to Drug Delivery

Periodic mesoporous ionosilica nanoparticles with ammonium walls were synthesized exclusively from a trisilylated ammonium precursor. The nanoparticles display a uniform particle size, together with a high specific surface area and an ordered hexagonal pore architecture. Completely biocompatible in vitro and in vivo, the nanoparticles are efficiently endocytosed by RAW 264.7 macrophages and used as carrier vehicles for anionic drugs. Diclofenac-loaded ionosilica nanoparticles are very efficient in inhibiting lipopolysaccharides-induced inflammation.