Neuroprotective Effects of Sinomenine on Experimental Autoimmune Encephalomyelitis via Anti-Inflammatory and Nrf2-Dependent Anti-Oxidative Stress Activity.

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS). Sinomenine (SIN), a bioactive alkaloid extracted from the Chinese medicinal plant Sinomenium acutum, has powerful anti-inflammatory and immunosuppressive therapeutic benefits. In our previous research, we found that SIN increased resistance to oxidative stress via the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in PC12 neuronal cells. However, whether SIN can improve the symptoms and pathological features of experimental autoimmune encephalomyelitis (EAE), a murine model of MS, via the Nrf2 signaling pathway remains unclear. EAE was immunized followed by SIN treatment. Then we evaluated the effects of SIN in EAE. Subsequently, primary microglia were cultured to explore the effect of SIN on microglia activation. Further, the levels of Nrf2 and its downstream molecules were detected to assess the molecular mechanisms of SIN. We demonstrated that SIN effectively ameliorated the severity of EAE, accompanied by a reduction in the demyelination, axonal damage and inhibition of inflammatory cell infiltration. Mechanistically, SIN decreased the inflammatory cytokines expression, and suppressed microglia and astrocytes activation in EAE mice. Furthermore, SIN suppressed lipopolysaccharide (LPS)-induced microglial activation and the production of pro-inflammatory factors in vitro. Moreover, SIN inhibited oxidative stress via the activation of the Nrf2 signaling pathway. Our work proves that SIN exerts its neuroprotective effects by the Nrf2-dependent anti-oxidative stress and diminishing neuroinflammation, suggesting that the "antioxiflammation" effect of SIN is expected to be an ideal treatment strategy for MS/EAE.

The key roles of reactive oxygen species in microglial inflammatory activation: Regulation by endogenous antioxidant system and exogenous sulfur-containing compounds.

Aberrant innate immunity in the brain has been implicated in the pathogenesis of several central nervous system (CNS) disorders, including Alzheimer's disease, Huntington's disease, Parkinson's disease, stroke, amyotrophic lateral sclerosis, and depression. Except for extraparenchymal CNS-associated macrophages, which predominantly afford protection against peripheral invading pathogens, it has been reported that microglia, a population of macrophage-like cells governing CNS immune defense in nearly all neurological diseases, are the main CNS resident immune cells. Although microglia have been recognized as the most important source of reactive oxygen species (ROS) in the CNS, ROS also may underlie microglial functions, especially M1 polarization, by modulating redox-sensitive signaling pathways. Recently, endogenous antioxidant systems, including glutathione, hydrogen sulfide, superoxide dismutase, and methionine sulfoxide reductase A, were found to be involved in regulating microglia-mediated neuroinflammation. A series of natural sulfur-containing compounds, including S-adenosyl methionine, S-methyl-L-cysteine, sulforaphane, DMS, and S-alk(enyl)-l-cysteine sulfoxide, modulating endogenous antioxidant systems have been discovered. We have summarized the current knowledge on the involvement of endogenous antioxidant systems in regulating microglial inflammatory activation and the effects of sulfur-containing compounds on endogenous antioxidant systems. Finally, we discuss the possibilities associated with compounds targeting the endogenous antioxidant system to treat neuroinflammation-associated diseases.

Self-therapeutic metal-based nanoparticles for treating inflammatory diseases.

Inflammatory diseases are key contributors to high mortality globally and adversely affect the quality of life. Current treatments include corticosteroids or nonsteroidal anti-inflammatories that may cause systemic toxicity and biologics that may increase the risk of infection. Composite nanoparticles that bear not only the drug payload but also targeting ligands for delivery to inflammation sites at lowered systemic toxicity are established in the nanomedicine field, but their relatively large size often leads to systemic clearance. Metal-based nanoparticles with intrinsic anti-inflammatory properties represent attractive alternatives. They are not only designed to be compact for crossing biological barriers (with the nanoparticle serving as a dual carrier and drug), but also support label-free tracking of their interactions with cells. The review commences with an outline of the common inflammatory diseases, inflammatory pathways involved, and conventional drug-loaded nanoparticles for anti-inflammation. Next, the review features the emerging applications of self-therapeutic metal-based nanoparticles (e.g., gold, coper oxide, platinum, ceria, and zinc oxide) for managing inflammatory diseases in animals over the past three years, focusing on therapeutic outcomes and anti-inflammatory mechanisms. The review concludes with an outlook on the biodistribution, long-term toxicity, and clinical translation of self-therapeutic metal-based nanoparticles.

Scavenger receptor-targeted plaque delivery of microRNA-coated nanoparticles for alleviating atherosclerosis.

Atherosclerosis treatments by gene regulation are garnering attention, yet delivery of gene cargoes to atherosclerotic plaques remains inefficient. Here, we demonstrate that assembly of therapeutic oligonucleotides into a three-dimensional spherical nucleic acid nanostructure improves their systemic delivery to the plaque and the treatment of atherosclerosis. This noncationic nanoparticle contains a shell of microRNA-146a oligonucleotides, which regulate the NF-κB pathway, for achieving transfection-free cellular entry. Upon an intravenous injection into apolipoprotein E knockout mice fed with a high-cholesterol diet, this nanoparticle naturally targets class A scavenger receptor on plaque macrophages and endothelial cells, contributing to elevated delivery to the plaques (∼1.2% of the injected dose). Repeated injections of the nanoparticle modulate genes related to immune response and vascular inflammation, leading to reduced and stabilized plaques but without inducing severe toxicity. Our nanoparticle offers a safe and effective treatment of atherosclerosis and reveals the promise of nucleic acid nanotechnology for cardiovascular disease.

Alkyl-Terminated Gold Nanoparticles as a Self-Therapeutic Treatment for Psoriasis.

We present a self-therapeutic nanoparticle for topical delivery to epidermal keratinocytes to prevent and treat psoriasis. Devoid of known chemical or biological antipsoriatic drugs, this sub-15 nm nanoparticle contains a 3 nm gold core and a shell of 1000 Da polyethylene glycol strands modified with 30% octadecyl chains. When it is applied to imiquimod-induced psoriasis mice without an excipient, the nanoparticle can cross the stratum corneum and preferentially enter keratinocytes. Applying the nanoparticles concurrently with imiquimod prevents psoriasis and downregulates genes that are enriched in the downstream of the interleukin-17 signaling pathway and linked to epidermis hyperproliferation and inflammation. Applying the nanoparticles after psoriasis is established treats the psoriatic skin as effectively as standard steroid and vitamin D analog-based therapy but without hair loss and skin wrinkling. The nanoparticles do not accumulate in major organs or induce long-term toxicity. Our nanoparticle offers a simple, safe, and effective alternative for treating psoriasis.

Immobilising hairpin DNA-conjugated distyryl boron dipyrromethene on gold@polydopamine core-shell nanorods for microRNA detection and microRNA-mediated photodynamic therapy.

A novel nanosystem of polydopamine-coated gold nanorods (AuNR@PDA) immobilised with molecules of hairpin DNA-conjugated distyryl boron dipyrromethene (DSBDP) was designed and fabricated for detection of microRNA-21 (miR-21). By using this oncogenic stimulus, the photodynamic effect of the DSBDP-based photosensitiser was also activated. In the presence of miR-21, the fluorescence intensity of the nanosystem was increased due to the dissociation of the conjugate from AuNR@PDA upon hybridisation. The intracellular fluorescence intensity triggered by intracellular miR-21 was in the order: MCF-7 > HeLa > HEK-293, which was in accordance with their miR-21 expression levels. The specificity was demonstrated by comparing the results with those of an analogue with a scrambled DNA sequence. The nanosystem could also result in miR-21-mediated photodynamic eradication of miR-21-overexpressed MCF-7 cells. After intravenous injection of the nanosystem into HeLa tumour-bearing nude mice, the fluorescence intensity of the tumour was increased over 24 h and was about 3-fold stronger than that of the scrambled analogue. Upon irradiation, the nanosystem could also greatly reduce the size of the tumour without causing significant tissue damage in the major organs. The overall results showed that this nanoplatform can serve as a specific and potent theranostic agent for simultaneous miR-21 detection and miR-21-mediated photodynamic therapy.

Oscillating Magnetic Field Regulates Cell Adherence and Endothelialization Based on Magnetic Nanoparticle-Modified Bacterial Cellulose.

Despite the widely explored biomaterial scaffolds in vascular tissue engineering applications lately, no ideal platform has been provided for small diameter synthetic vascular grafts mainly due to the thrombosis issue. Endothelium is the only known completely non-thrombogenic material; so, functional endothelialization onto vascular biomaterials is critical in maintaining the patency of vascular networks. Bacterial cellulose (BC) is a natural biomaterial with superior biocompatibility and appropriate hydrophilicity as potential vascular grafts. In previous studies, surface modification of active peptides such as Arg-Gly-Asp (RGD) sequences onto biomaterials has been proven to achieve accelerated and selective endothelial cell (EC) adhesion. In our study, we demonstrated a new strategy to remotely regulate the adhesion of endothelial cells based on an oscillating magnetic field and achieve successful endothelialization on the modified BC membranes. In details, we synthesized bacterial cellulose (BC), magnetic BC (MBC), and RGD peptide-grafted magnetic BC (RMBC), modified with the HOOC-PEG-COOH-coated iron oxide nanoparticles (PEG-IONs). The endothelial cells were cultured on the three materials under different frequencies of an oscillating magnetic field, including "stationary" (0 Hz), "slow" (0.1 Hz), and "fast" (2 Hz) groups. Compared to BC and MBC membranes, the cells on RMBC membranes generally show better adhesion and proliferation. Meanwhile, the "slow" frequency of a magnetic field promotes this phenomenon on RMBC and achieves endothelialization after culture for 4 days, whereas "fast" inhibits the cellular attachment. Overall, we demonstrate a non-invasive and convenient method to regulate the endothelialization process, with promising applications in vascular tissue engineering.

Nano-Cell Interactions of Non-Cationic Bionanomaterials.

Advances in nanotechnology have empowered the design of bionanomaterials by assembling different types of natural biomolecules (e.g., nucleic acids, proteins, and lipids) as building blocks into nanoparticles (NPs) of 1-100 nm in diameter. Such bionanomaterials form the basis of useful nanomedicine applications, such as targeted delivery, gene regulation, molecular diagnostics, and immunomodulation. To achieve optimal performance in these applications, it is imperative that the NPs be delivered effectively to the organs, tissues, and cells of interest. A rational approach to facilitating the delivery of NPs is to develop a detailed and comprehensive understanding in their fundamental interactions with the biological system (or nano-bio interactions). Rigorous nano-bio research can provide mechanistic insights for circumventing the bottlenecks associated with inefficient and nonspecific delivery of NPs, catalyzing the clinical translation of nanomedicines. Cationic liposomes and lipid NPs are conventional carriers of therapeutic cargoes into cells due to their high ability to penetrate the cell membrane, a barrier comprised by an anionic phospholipid bilayer. Yet, cationic NPs tend to cause cytotoxicity and immune responses that may hamper their clinical translation. Contrary to cationic NPs, non-cationic NPs (be they near-neutral or anionic in surface charge) generally exhibit higher biocompatibility but enter mammalian cells in much less pronounced amounts. Intriguingly, some types of non-cationic NPs exhibit high biocompatibility and cellular uptake properties, all attractive features for intracellular delivery. In this Account, we present our studies of the interactions of non-cationic bionanomaterials with cells (or nano-cell interactions). To start with, we introduce the use of near-neutral poly(ethylene glycol)-coated NPs for probing the roles of two rarely explored physicochemical parameters on cellular uptake, namely, extracellular compression and alkylation. We next present the nano-cell interactions of two representative types of anionic bionanomaterials that effectively enter mammalian cells and have found widespread applications in the past decade, including DNA-coated NPs and polydopamine (PDA)-coated NPs. In our cell-based studies, we dissect the route of intracellular trafficking, pathway proteins that dictate cellular uptake, and trafficking of NPs. We further touch on our recent quantitative analysis of the cellular-level distribution of NPs in various organs and tissues of diseased animal models. Our results offer important design rules of NPs for achieving effective intracellular delivery and may even guide us to explore nanomedicine applications that we did not conceive before, such as using DNA-coated NPs for targeting atherosclerotic plaques and PDA-coated plasmonic nanoworms for photothermal killing of cancer cells. We conclude with our perspectives in elucidating nano-bio interactions via a reductionist approach, calling for closer attention to the role of functional groups and more refined studies on the organelle-level distribution of NPs and the genetic basis of in vivo distribution of NPs.

Promoting the Delivery of Nanoparticles to Atherosclerotic Plaques by DNA Coating.

Many nanoparticle-based carriers to atherosclerotic plaques contain peptides, lipoproteins, and sugars, yet the application of DNA-based nanostructures for targeting plaques remains infrequent. In this work, we demonstrate that DNA-coated superparamagnetic iron oxide nanoparticles (DNA-SPIONs), prepared by attaching DNA oligonucleotides to poly(ethylene glycol)-coated SPIONs (PEG-SPIONs), effectively accumulate in the macrophages of atherosclerotic plaques following an intravenous injection into apolipoprotein E knockout (ApoE-/-) mice. DNA-SPIONs enter RAW 264.7 macrophages faster and more abundantly than PEG-SPIONs. DNA-SPIONs mostly enter RAW 264.7 cells by engaging Class A scavenger receptors (SR-A) and lipid rafts and traffic inside the cell along the endolysosomal pathway. ABS-SPIONs, nanoparticles with a similarly polyanionic surface charge as DNA-SPIONs but bearing abasic oligonucleotides also effectively bind to SR-A and enter RAW 264.7 cells. Near-infrared fluorescence imaging reveals evident localization of DNA-SPIONs in the heart and aorta 30 min post-injection. Aortic iron content for DNA-SPIONs climbs to the peak (∼60% ID/g) 2 h post-injection (accompanied by profuse accumulation in the aortic root), but it takes 8 h for PEG-SPIONs to reach the peak aortic amount (∼44% ID/g). ABS-SPIONs do not appreciably accumulate in the aorta or aortic root, suggesting that the DNA coating (not the surface charge) dictates in vivo plaque accumulation. Flow cytometry analysis reveals more pronounced uptake of DNA-SPIONs by hepatic endothelial cells, splenic macrophages and dendritic cells, and aortic M2 macrophages (the cell type with the highest uptake in the aorta) than PEG-SPIONs. In summary, coating nanoparticles with DNA is an effective strategy of promoting their systemic delivery to atherosclerotic plaques.

TaMIR1139: a wheat miRNA responsive to Pi-starvation, acts a critical mediator in modulating plant tolerance to Pi deprivation.

KEY MESSAGE: Wheat miRNA member TaMIR1139 targets genes functional in various families and plays crucial roles in regulating plant Pi starvation tolerance. Through regulating target genes at posttranscriptional or translational level, plant miRNAs are involved in mediating diverse biological processes associated with growth, development, and responses to adverse stresses. In this study, we characterized the expression pattern and function of TaMIR1139, a miRNA member of wheat (T. aestivum) under Pi deprivation. TaMIR1139 precursor is also present in N. tabucum, suggesting the conserved nature of miR1139 across monocots and eudicots. TaMIR1139 targets seven genes within different families. The transcripts abundance of TaMIR1139 was induced upon Pi deprivation and the upregulated expression under Pi starvation was downregulated by the Pi recovery treatment, In contrast, the genes targeted by TaMIR1139 exhibited reduced transcripts upon Pi starvation and their downregulated expression was recovered by Pi-recovery condition, suggesting the regulation of them under TaMIR1139 through a cleavage mechanism. TaMIR1139 overexpression conferred the Pi-deprived plants improved phenotype, biomass, photosynthesis, and Pi acquisition. Transcriptome analysis identified numerous genes involving biological process, cellular components, and molecular function were differentially expressed in the TaMIR1139 overexpression lines, which suggests the TaMIR1139-mediated plant Pi starvation tolerance to be associated with the role of miRNA in extensively modulating the transcript profiling. A phosphate transporter (PT) gene NtPT showed significantly upregulated expression in TaMIR1139 overexpression lines; overexpression of it conferred plants improved Pi acquisition upon Pi starvation, suggesting its contribution to the TaMIR1139-mediated plant low-Pi stress resistance. Our investigation indicates that TaMIR1139 is critical in plant Pi starvation tolerance through transcriptionally regulating the target genes and modulating the Pi stress-defensiveness processes.

Wheat miRNA TaemiR408 Acts as an Essential Mediator in Plant Tolerance to Pi Deprivation and Salt Stress via Modulating Stress-Associated Physiological Processes.

MicroRNAs (miRNA) families act as critical regulators for plant growth, development, and responses to abiotic stresses. In this study, we characterized TaemiR408, a miRNA family member of wheat (Triticum aestivum), for the role in mediating plant responses to Pi starvation and salt stress. TaemiR408 targets six genes that encode proteins involving biochemical metabolism, microtubule organization, and signaling transduction. 5'- and 3'-RACE analyses confirmed the mRNA cleavage of target genes mediated by this wheat miRNA. TaemiR408 showed induced expression patterns upon Pi starvation and salt stress and whose upregulated expression was gradually repressed by the normal recovery treatments. The target genes of TaemiR408 exhibited reverse expression patterns to this miRNA, whose transcripts were downregulated under Pi starvation and salt stress and the reduced expression was recovered by the followed normal condition. These results suggest the regulation of the target genes under TaemiR408 through a cleavage mechanism. Tobacco lines with TaemiR408 overexpression exhibited enhanced stress tolerance, showing improved phenotype, biomass, and photosynthesis behavior compared with wild type under both Pi starvation and salt treatments, which closely associate increased P accumulation upon Pi deprivation and elevated osmolytes under salt stress, respectively. Phosphate transporter (PT) gene NtPT2 displays upregulated transcripts in the Pi-deprived TaemiR408 overexpressors; knockdown of this PT gene reduces Pi acquisition under low-Pi stress, confirming its role in improving plant Pi taken up. Likewise, NtPYL2 and NtSAPK3, genes encoding abscisic acid (ABA) receptor and SnRK2 protein, respectively, exhibited upregulated transcripts in salt-challenged TaemiR408 overexpressors; knockdown of them caused deteriorated growth and lowered osmolytes amounts of plants upon salt treatment. Thus, TaemiR408 is crucial for plant adaptations to Pi starvation and salt stress through regulating Pi acquisition under low-Pi stress and remodel ABA signaling pathway and osmoprotects biosynthesis under salt stress.

Core-extended terrylene diimide on the bay region: synthesis and optical and electrochemical properties.

Two novel core-extended terrylene diimides on the bay region (CETDIs) were synthesized via annulation of the four additional ethylene units or benzene units on the bay region of the terrylene diimide core. The optical and electrochemical properties of the two compounds were investigated. These CETDIs exhibited broad absorption spectra with high extinction coefficients, which span a wide range in the ultraviolet and visible spectrum from 300 to 700 nm. Furthermore, the redox process of the CETDIs increased from two waves to four waves, and the lowest unoccupied molecular orbital (LUMO) levels were enhanced from -4.00 to -3.59 eV.

Water-soluble and fluorescent dendritic perylene bisimides for live-cell imaging.

We prepared dendritic perylene bisimide probes with triblock structures: perylene bisimides fluorescence cores, branched oligo(glutamic acid)s and polyethylene glycol chains. These probes showed good water solubility, low cytotoxicity and strong fluorescence in live cells.