ROS-responsive charge reversal mesoporous silica nanoparticles as promising drug delivery system for neovascular retinal diseases.

Intravitreal injection of biodegradable implant drug carriers shows promise in reducing the injection frequency for neovascular retinal diseases. However, current intravitreal ocular devices have limitations in adjusting drug release rates for individual patients, thereby affecting treatment effectiveness. Accordingly, we developed mesoporous silica nanoparticles (MSNs) featuring a surface that reverse its charge in response to reactive oxygen species (ROS) for efficient delivery of humanin peptide (HN) to retinal epithelial cells (ARPE-19).

Autophagosome-lysosome fusion is facilitated by plectin-stabilized actin and keratin 8 during macroautophagic process.

Autophagy is a lysosome-mediated degradative process that removes damaged proteins and organelles, during which autophagosome-lysosome fusion is a key step of the autophagic flux. Based on our observation that intermediate cytofilament keratin 8 (KRT8) enhances autophagic clearance in cells under oxidative stress condition, we investigated whether KRT8 supports the cytoplasmic architectural networks to facilitate the vesicular fusion entailing trafficking onto filamentous tracks. We found that KRT8 interacts with actin filaments via the cytolinker, plectin (PLEC) during trafficking of autophagosome.

Recent Advances in Surface-Enhanced Raman Scattering Magnetic Plasmonic Particles for Bioapplications.

The surface-enhanced Raman scattering (SERS) technique, that uses magnetic plasmonic particles (MPPs), is an advanced SERS detection platform owing to the synergetic effects of the particles' magnetic and plasmonic properties. As well as being an ultrasensitive and reliable SERS material, MPPs perform various functions, such as aiding in separation, drug delivery, and acting as a therapeutic material. This literature discusses the structure and multifunctionality of MPPs, which has enabled the novel application of MPPs to various biological fields.

KRT8 (keratin 8) attenuates necrotic cell death by facilitating mitochondrial fission-mediated mitophagy through interaction with PLEC (plectin).

Dysregulation of mitochondrial homeostasis and accumulation of damaged mitochondria cause degenerative diseases such as age-related macular degeneration (AMD). We studied the effects of the intermediate cytofilament KRT8 (keratin 8) on mitochondrial homeostasis in relation to the morphology and function of mitochondria in retinal pigment epithelial cells under oxidative stress. When the mitochondria were damaged owing to oxidative stress, the damaged mitochondria were readily disposed of via mitophagy following mitochondrial fission.

Autophagy down-regulates NLRP3-dependent inflammatory response of intestinal epithelial cells under nutrient deprivation.

Dysregulation of inflammation induced by noninfectious stress conditions, such as nutrient deprivation, causes tissue damage and intestinal permeability, resulting in the development of inflammatory bowel diseases. We studied the effect of autophagy on cytokine secretion related to intestinal permeability under nutrient deprivation. Autophagy removes NLRP3 inflammasomes via ubiquitin-mediated degradation under starvation.

LMP2 Inhibitors as a Potential Treatment for Alzheimer's Disease.

The immunoproteasome (iP), an inducible proteasome variant harboring three immunosubunits, low molecular mass polypeptide-2 (LMP2), multicatalytic endopeptidase complex subunit-1, and low molecular mass polypeptide-7 (LMP7), is involved in multiple facets of inflammatory responses. We recently reported that YU102, a dual inhibitor of the iP subunit LMP2 and the constitutive proteasome catalytic subunit β1, ameliorates cognitive impairments in mouse models of Alzheimer's disease (AD) independently of amyloid deposits. To investigate whether inhibition of LMP2 is sufficient to improve the cognitive functions of AD mice, here we prepared 37 YU102 analogues and identified a potent LMP2 inhibitor DB-310 () (IC: 80.

A dual inhibitor of the proteasome catalytic subunits LMP2 and Y attenuates disease progression in mouse models of Alzheimer's disease.

The immunoproteasome (iP) is a variant of the constitutive proteasome (cP) that is abundantly expressed in immune cells which can also be induced in somatic cells by cytokines such as TNF-α or IFN-γ. Accumulating evidence support that the iP is closely linked to multiple facets of inflammatory response, eventually leading to the development of several iP inhibitors as potential therapeutic agents for autoimmune diseases. Recent studies also found that the iP is upregulated in reactive glial cells surrounding amyloid β (Aβ) deposits in brains of Alzheimer's disease (AD) patients, but the role it plays in the pathogenesis of AD remains unclear.

The bacterial endoribonuclease RNase E can cleave RNA in the absence of the RNA chaperone Hfq.

RNase E is a component of the RNA degradosome complex and plays a key role in RNA degradation and maturation in RNase E-mediated target RNA degradation typically involves the RNA chaperone Hfq and requires small guide RNAs (sRNAs) acting as a seed by binding to short (7-12-bp) complementary regions in target RNA sequences. Here, using recombinantly expressed and purified proteins, site-directed mutagenesis, and RNA cleavage and protein cross-linking assays, we investigated Hfq-independent RNA decay by RNase E. Exploring its RNA substrate preferences in the absence of Hfq, we observed that RNase E preferentially cleaves AU-rich sites of single-stranded regions of RNA substrates that are annealed to an sRNA that contains a monophosphate at its 5'-end.

Oxidative stress causes Alu RNA accumulation via PIWIL4 sequestration into stress granules.

The Alu element, the most abundant transposable element, is transcribed to Alu RNA. We hypothesized that the PIWI protein regulates the expression of Alu RNA in retinal pigment epithelial (RPE) cells, where accumulated Alu RNA leads to macular degeneration. Alu transcription was induced in RPE cells treated with H2O2.

Polyethylene Glycol-Engrafted Graphene Oxide as Biocompatible Materials for Peptide Nucleic Acid Delivery into Cells.

Graphene oxide (GO) is known to strongly bind single-stranded nucleic acids with fluorescence quenching near the GO surface. However, GO exhibits weak biocompatibility characteristics, such as low dispersibility in cell culture media and significant cytotoxicity. To improve dispersibility in cell culture media and cell viability of GO, we prepared nanosized GO (nGO) constructs and modified the nGO surface using polyethylene glycol (PEG-nGO).

Graphene Oxide Conjugated Magnetic Beads for RNA Extraction.

A magnetic material that consists of silica-coated magnetic beads conjugated with graphene oxide (GO) was successfully prepared for facile ribonucleic acid (RNA) extraction. When the GO-modified magnetic beads were applied to separate the RNA from the lysed cell, the cellular RNAs were readily adsorbed to and readily desorbed from the surface of the GO-modified magnetic beads by urea. The amount of RNA extracted by the GO-modified magnetic beads was ≈170 % as much as those of the control extracted by a conventional phenol-based chaotropic solution.

Autophagy and KRT8/keratin 8 protect degeneration of retinal pigment epithelium under oxidative stress.

Contribution of autophagy and regulation of related proteins to the degeneration of retinal pigment epithelium (RPE) in age-related macular degeneration (AMD) remain unknown. We report that upregulation of KRT8 (keratin 8) as well as its phosphorylation are accompanied with autophagy and attenuated with the inhibition of autophagy in RPE cells under oxidative stress. KRT8 appears to have a dual role in RPE pathophysiology.

Facilitation of Polymerase Chain Reaction with Poly(ethylene glycol)-Engrafted Graphene Oxide Analogous to a Single-Stranded-DNA Binding Protein.

Polymerase chain reaction (PCR), a versatile DNA amplification method, is a fundamental technology in modern life sciences and molecular diagnostics. After multiple rounds of PCR, however, nonspecific DNA fragments are often produced and the amplification efficiency and fidelity decrease. Here, we demonstrated that poly(ethylene glycol)-engrafted nanosized graphene oxide (PEG-nGO) can significantly improve the PCR specificity and efficiency.

Fluorometric Detection of MicroRNA Using Isothermal Gene Amplification and Graphene Oxide.

We have developed a facile fluorometric system for the detection of microRNA (miRNA), using rolling circle amplification (RCA), graphene oxide (GO), and fluorescently labeled peptide nucleic acid (F-PNA). The padlock probe DNA complementary to a target miRNA was selectively ligated to form circular DNA that was then used as the template for RCA. F-PNAs complementary to the target miRNA were annealed to multiple sites of the isothermally amplified single-stranded RCA product (RCAP) containing multiple target miRNA sequences.

Fluorescence-based detection of single-nucleotide changes in RNA using graphene oxide and DNAzyme.

We report a simple fluorometric method for detection of single-nucleotide changes in RNA using graphene oxide (GO) and RNA-cleaving DNAzyme. The fluorescent DNA probe (F-DNA) was annealed to RNA fragments generated by RNA cleavage with DNAzyme specific to mutant RNA. The F-DNA-RNA duplex attenuated the quenching of F-DNA fluorescence by GO.

A graphene oxide-based platform for the assay of RNA synthesis by RNA polymerase using a fluorescent peptide nucleic acid probe.

We report a simple, direct fluorometric assay based on graphene oxide (GO) for RNA polymerase-mediated RNA synthesis. In principle, fluorescent peptide nucleic acid (PNA) probes were designed, and annealed with RNA products and the resultant RNA-PNA hybrids induced the recovery of fluorescence intensity of the PNA probes adsorbed onto the GO surface.