Oral Administration of Resveratrol-Selenium-Peptide Nanocomposites Alleviates Alzheimer's Disease-like Pathogenesis by Inhibiting Aß Aggregation and Regulating Gut Microbiota.

Alzheimer's disease (AD) is a neurodegenerative disease associated with amyloid-ß (Aß) deposition, leading to neurotoxicity (oxidative stress and neuroinflammation) and gut microbiota imbalance. Resveratrol (Res) has neuroprotective properties, but its bioavailability in vivo is very low. Herein, we developed a small Res-selenium-peptide nanocomposite to enable the application of Res for eliminating Aß aggregate-induced neurotoxicity and mitigating gut microbiota disorder in aluminum chloride (AlCl3) and d-galactose(d-gal)-induced AD model mice. Res functional selenium nanoparticles (Res@SeNPs) (8 ± 0.34 nm) were prepared first, after which the surface of Res@SeNPs was decorated with a blood-brain barrier transport peptide (TGN peptide) to generate Res-selenium-peptide nanocomposites (TGN-Res@SeNPs) (14 ± 0.12 nm). Oral administration of TGN-Res@SeNPs improves cognitive disorder through (1) interacting with Aß and decreasing Aß aggregation, effectively inhibiting Aß deposition in the hippocampus; (2) decreasing Aß-induced reactive oxygen species (ROS) and increasing activity of antioxidation enzymes in PC12 cells and in vivo; (3) down-regulating Aß-induced neuroinflammation via the nuclear factor kappa B/mitogen-activated protein kinase/Akt signal pathway in BV-2 cells and in vivo; and (4) alleviating gut microbiota disorder, particularly with respect to oxidative stress and inflammatory-related bacteria such as Alistipes, Helicobacter, Rikenella, Desulfovibrio, and Faecalibaculum. Thus, we anticipate that Res-selenium-peptide nanocomposites will offer a new potential strategy for the treatment of AD.

Smart Design of a pH-Responsive System Based on pHLIP-Modified Magnetite Nanoparticles for Tumor MRI.

Magnetic Fe3O4 nanoparticles (MNPs) are often used to design agents enhancing contrast in magnetic resonance imaging (MRI) that can be considered as one of the efficient methods for cancer diagnostics. At present, increasing the specificity of the MRI contrast agent accumulation in tumor tissues remains an open question and attracts the attention of a wide range of researchers. One of the modern methods for enhancing the efficiency of contrast agents is the use of molecules for tumor acidic microenvironment targeting, for example, pH-low insertion peptide (pHLIP). We designed novel organosilicon MNPs covered with poly(ethylene glycol) (PEG) and covalently modified by pHLIP. To study the specific features of the binding of pHLIP-modified MNPs to cells, we also obtained nanoconjugates with Cy5 fluorescent dye embedded in the SiO2 shell. The nanoconjugates obtained were characterized by transmission electron microscopy (TEM), attenuated total reflection (ATR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), dynamic light scattering (DLS), UV and fluorescence spectrometry, thermogravimetric analysis (TGA), CHN elemental analyses, and vibrating sample magnetometry. Low cytotoxicity and high specificity of cellular uptake of pHLIP-modified MNPs at pH 6.4 versus 7.4 (up to 23-fold) were demonstrated in vitro. The dynamics of the nanoconjugate accumulation in the 4T1 breast cancer orthotopically grown in BALB/c mice and MDA-MB231 xenografts was evaluated in MRI experiments. Biodistribution and biocompatibility studies of the obtained nanoconjugate showed no pathological change in organs and in the blood biochemical parameters of mice after MNP administration. A high accumulation rate of pHLIP-modified MNPs in tumor compared with PEGylated MNPs after their intravenous administration was demonstrated. Thus, we propose a promising approach to design an MRI agent with the tumor acidic microenvironment targeting ability.

Self-assembled chitosan polymer intercalating peptide functionalized gold nanoparticles as nanoprobe for efficient imaging of urokinase plasminogen activator receptor in cancer diagnostics.

Targeting cell surface receptors for specific drug delivery in cancer has garnered lot of attention. Urokinase plasminogen activator receptor (uPAR), a surface biomarker, is overexpressed on many tumours including breast, colorectal, prostate, and ovarian cancers. Binding of growth factor domain (GFD) of urokinase plasminogen activator (uPA) with uPAR lead to its close conformation, and allow somatomedin B domain (SMB) of vitronectin binding by allosteric modulation. In-silico docking of uPAR with GFD and SMB peptides was performed to identify potential binding affinity. Herein, we report fluorescently labeled peptide functionalized AuNPs with a mixed self-assembled monolayer of intercalating chitosan polymer for efficient targeting and imaging of uPAR-positive cells. The biophysical characterization of nanoconjugates and uPAR-specific targeting was assessed by FACS, cell adhesion, and fluorescence imaging. AuNPs/chitosan/GFD+SMB peptides showed higher uptake as compared to AuNPs/chitosan/GFD, and AuNPs/chitosan/SMB that can be utilized as a tool for molecular targeting and imaging in metastasis.

A Cell Microarray Format: A Peptide Release System Using a Photo-Cleavable Linker for Cell Toxicity and Cell Uptake Analysis.

There has been increasing interest in the potential use of microarray technologies to perform systematic and high-throughput cell-based assays. We are currently focused on developing more practical array formats and detection methods that will enable researchers to conduct more detailed analyses in cell microarray studies. In this chapter, we describe the construction of a novel peptide-array format system for analyzing cellular toxicity and cellular uptake. In this system, a peptide is immobilized at the bottom of a conventional 96-well plate using a photo-cleavable linker. The peptide can then be released from the bottom by irradiating the desired wells with UV light, thus allowing the cytotoxicity or cellular uptake of the peptide to be monitored. This system will facilitate the realization of high-throughput cell arrays for cellomics analyses and cell-based phenotypic drug screens.