Injectable and biodegradable piezoelectric hydrogel for osteoarthritis treatment.

Osteoarthritis affects millions of people worldwide but current treatments using analgesics or anti-inflammatory drugs only alleviate symptoms of this disease. Here, we present an injectable, biodegradable piezoelectric hydrogel, made of short electrospun poly-L-lactic acid nanofibers embedded inside a collagen matrix, which can be injected into the joints and self-produce localized electrical cues under ultrasound activation to drive cartilage healing. In vitro, data shows that the piezoelectric hydrogel with ultrasound can enhance cell migration and induce stem cells to secrete TGF-ß1, which promotes chondrogenesis. In vivo, the rabbits with osteochondral critical-size defects receiving the ultrasound-activated piezoelectric hydrogel show increased subchondral bone formation, improved hyaline-cartilage structure, and good mechanical properties, close to healthy native cartilage. This piezoelectric hydrogel is not only useful for cartilage healing but also potentially applicable to other tissue regeneration, offering a significant impact on the field of regenerative tissue engineering.

Annulation of O-silyl N,O-ketene acetals with alkynes for the synthesis of dihydropyridinones and its application in concise total synthesis of phenanthroindolizidine alkaloids.

The formation of N-heterocycles with multiple substituents is important in organic synthesis. Herein, we report a novel method for the construction of functionalized dihydropyridinone rings through the annulation of an amide α-carbon with a tethered alkyne moiety. The reaction of the amide with the alkyne was achieved via O-silyl N,O-ketene acetal formation and silver-mediated addition. Furthermore, the developed method was applied for the total synthesis of phenanthroindolizidine and phenanthroquinolizidine alkaloids. By varying the coupling partners, a concise and collective total synthesis of these alkaloids was achieved.

IL-31RA and TRPV1 Expression in Atopic Dermatitis Induced with Trinitrochlorobenzene in Nc/Nga Mice.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Interleukin 31 (IL-31), a novel cytokine in AD, causes pruritus, typically characteristic of AD patients. The transient receptor potential vanilloid type 1 (TRPV1) is a cation channel activated by diverse noxious stimuli that has been studied in a variety of pruritic skin diseases. In this study, the AD animal model was generated by administering the hapten, trinitrochlorobenzene (TNCB), to Nc/Nga mice, and the degree of expression of the IL-31 receptor alpha (IL-31RA) and TRPV1 in the skin of these atopic models was evaluated. The Nc/Nga mice were divided into 3 groups: control, TNCB 2-weeks treated, and TNCB 8-weeks treated. After inducing AD, the skin lesions in each group were scored and compared, and the histology of the skin lesions and the IL-31RA and TRPV1 expression for each group were evaluated by analyzing immunohistochemistry. The results show a significant difference in the skin lesion scores between the groups. The immunohistochemistry evaluation highlighted the remarkable expression of IL-31RA and TRPV1 in the nerve fibers of the TNCB 8-weeks-treated group. We thus confirmed that the long-term application of TNCB induced chronic atopic-like dermatitis and that IL-31RA and TRPV1 were overexpressed in the peripheral nerve fibers in this AD model.

Sialic acid-decorated liposomes enhance the anti-cancer efficacy of docetaxel in tumor-associated macrophages.

Tumor-associated macrophages (TAMs) in the tumor microenvironment potentially enhance tumor growth and invasion through various mechanisms and are thus an essential factor in tumor immunity. The highly expressed siglec-1 receptors on the surfaces of TAMs are potential targets for cancer drug delivery systems. Sialic acid (SA) is a specific ligand for siglec-1. In this study, the sialic acid-polyethylene glycol conjugate (DSPE-PEG2000-SA) was synthesized to modify the surface of liposomes and target TAMs by interacting with the siglec-1 receptor. Three docetaxel (DTX)-loaded liposomes, conventional (DTX-CL), DSPE-PEG2000-coated (DTX-PL), and DSPE-PEG2000-SA-coated (DTX-SAPL) liposomes, were prepared, with a particle size of <100 nm, uniform polydispersity index (PDI) values, negative zeta potential, and % encapsulation efficiency (EE) exceeding 95 %. Liposomes showed high stability after 3 months of storage at 4 °C without significant changes in particle size, PDI, zeta potential, or % EE. DTX was released from liposomes according to the Weibull model, and DTX-SAPL exhibited more rapid drug release than other liposomes. In vitro studies demonstrated that DTX-SAPL liposome exhibited a higher uptake and cytotoxicity on RAW 264.7 cells (TAM model) and lower toxicity on NIH3T3 cells (normal cell model) than other formulations. The high cell uptake ability was demonstrated by the role of the SA-SA receptor. Biodistribution studies indicated a high tumor accumulation of surface-modified liposomal formulations, particularly SA-modified liposomes, showing high signal accumulation at the tumor periphery, where TAMs were highly concentrated. Ex vivo imaging showed a significantly higher accumulation of SA-modified liposomes in the tumor, kidney, and heart than conventional liposomes. In the anti-cancer efficacy study, DTX-SAPL liposomes showed effective inhibition of tumor growth and relatively low systemic toxicity, as evidenced by the tumor volume, tumor weight, body weight values, and histopathological analysis. Therefore, DSPE-PEG2000-SA-coated liposomes could be promising carriers for DTX delivery targeting TAMs in cancer therapy.

Prediction of Cancer Metastasis Using Correlations Between miRNAs and Competing Endogenous RNAs.

Cancer metastasis is a complex process which involves the spread of tumor cells from the primary site to other parts of the body. Metastasis is the major cause of cancer mortality, accounting for about 90% of cancer deaths. Metastasis is primarily diagnosed by clinical examinations and imaging techniques, but such a diagnosis is made after metastasis has occurred. Prediction or early detection of metastasis is important for treatment planning since it has an impact on the survival of patients. Recently a few methods have been developed to predict lymph node metastasis, but few methods are available for predicting distant metastasis. Motivated by a gene regulation mechanism involving miRNAs, we have developed a new method for predicting both lymph node metastasis and distant metastasis. We have derived differential correlations of miRNAs and their target RNAs in cancer, and built prediction models using the differential correlations. Testing the method on several types of cancer showed that differential correlations of miRNAs and target RNAs are much more powerful and stable than expressions of known metastasis predictive genes in predicting distant metastasis as well as lymph node metastasis. The method developed in this study will be useful in predicting metastasis and thereby in determining treatment options for cancer patients.

Doxorubicin covalently conjugated heparin displays anti-cancer activity as a self-assembled nanoparticle with a low-anticoagulant effect.

Heparin is a glycosaminoglycans (GAGs) member and well-known FDA-approved anticoagulant that has been widely used in the clinic for 100 years. It has also been evaluated in various fields for further clinical applications, such as in anti-cancer or anti-inflammatory therapy beyond its anticoagulant effect. Here, we sought to utilize heparin molecules as drug carriers by directly conjugating the anticancer drug doxorubicin to the carboxyl group of unfractionated heparin. Given the molecular action of doxorubicin in intercalating DNA, it is expected to be less effective when structurally combined with other molecules. However, by utilizing doxorubicin molecules to produce reactive oxygen species (ROS), we found that the heparin-doxorubicin conjugates have significant cytotoxic ability to kill CT26 tumor cells with low anticoagulant activity. Several doxorubicin molecules were bound to heparin to provide sufficient cytotoxic capability and self-assembly ability due to their amphiphilic properties. The self-assembled formation of these nanoparticles was demonstrated through DLS, SEM and TEM. The cytotoxic ROS-generating doxorubicin-conjugated heparins could inhibit tumor growth and metastasis in CT26-bearing Balb/c animal models. Our results demonstrate that this cytotoxic doxorubicin-based heparin conjugate can significantly inhibit tumor growth and metastasis, thus showing promise as a potential new anti-cancer therapeutic.

Finding miRNA-RNA Network Biomarkers for Predicting Metastasis and Prognosis in Cancer.

Despite remarkable progress in cancer research and treatment over the past decades, cancer ranks as a leading cause of death worldwide. In particular, metastasis is the major cause of cancer deaths. After an extensive analysis of miRNAs and RNAs in tumor tissue samples, we derived miRNA-RNA pairs with substantially different correlations from those in normal tissue samples. Using the differential miRNA-RNA correlations, we constructed models for predicting metastasis. A comparison of our model to other models with the same data sets of solid cancer showed that our model is much better than the others in both lymph node metastasis and distant metastasis. The miRNA-RNA correlations were also used in finding prognostic network biomarkers in cancer patients. The results of our study showed that miRNA-RNA correlations and networks consisting of miRNA-RNA pairs were more powerful in predicting prognosis as well as metastasis. Our method and the biomarkers obtained using the method will be useful for predicting metastasis and prognosis, which in turn will help select treatment options for cancer patients and targets of anti-cancer drug discovery.

Lysosomal lipid peroxidation regulates tumor immunity.

Lysosomal inhibition elicited by palmitoyl-protein thioesterase 1 (PPT1) inhibitors such as DC661 can produce cell death, but the mechanism for this is not completely understood. Programmed cell death pathways (autophagy, apoptosis, necroptosis, ferroptosis, and pyroptosis) were not required to achieve the cytotoxic effect of DC661. Inhibition of cathepsins, or iron or calcium chelation, did not rescue DC661-induced cytotoxicity. PPT1 inhibition induced lysosomal lipid peroxidation (LLP), which led to lysosomal membrane permeabilization and cell death that could be reversed by the antioxidant N-acetylcysteine (NAC) but not by other lipid peroxidation antioxidants. The lysosomal cysteine transporter MFSD12 was required for intralysosomal transport of NAC and rescue of LLP. PPT1 inhibition produced cell-intrinsic immunogenicity with surface expression of calreticulin that could only be reversed with NAC. DC661-treated cells primed naive T cells and enhanced T cell-mediated toxicity. Mice vaccinated with DC661-treated cells engendered adaptive immunity and tumor rejection in "immune hot" tumors but not in "immune cold" tumors. These findings demonstrate that LLP drives lysosomal cell death, a unique immunogenic form of cell death, pointing the way to rational combinations of immunotherapy and lysosomal inhibition that can be tested in clinical trials.

Design and Evaluation of a Carrier-Free Prodrug-Based Palmitic-DEVD-Doxorubicin Conjugate for Targeted Cancer Therapy.

In the development of new drugs, typical polymer- or macromolecule-based nanocarriers suffer from manufacturing process complexity, unwanted systematic toxicity, and low loading capacity. However, carrier-free nanomedicines have made outstanding progress in drug delivery and pharmacokinetics, demonstrating most of the advantages associated with nanoparticles when applied in targeted anticancer therapy. Here, to overcome the problems of nanocarriers and conventional cytotoxic drugs, we developed a novel, carrier-free, self-assembled prodrug consisting of a hydrophobic palmitic (16-carbon chain n-hexadecane chain) moiety and hydrophilic group (or moiety) which is included in a caspase-3-specific cleavable peptide (Asp-Glu-Val-Asp, DEVD) and a cytotoxic drug (doxorubicin, DOX). The amphiphilic conjugate, the palmitic-DEVD-DOX, has the ability to self-assemble into nanoparticles in saline without the need for any carriers or nanoformulations. Additionally, the inclusion of doxorubicin is in its prodrug form and the apoptosis-specific DEVD peptide lead to the reduced side effects of doxorubicin in normal tissue. Furthermore, the carrier-free palmitic-DEVD-DOX nanoparticles could passively accumulate in the tumor tissues of tumor-bearing mice due to an enhanced permeation and retention (EPR) effect. As a result, the palmitic-DEVD-DOX conjugate showed an enhanced therapeutic effect compared with the unmodified DEVD-DOX conjugate. Therefore, this carrier-free palmitic-DEVD-DOX prodrug has great therapeutic potential to treat solid tumors, overcoming the problems of conventional chemotherapy and nanoparticles.

Facile One-Pot Synthesis of Polysubstituted Pyridinium Salts by Annulation of Enamines with Alkynes.

An efficient and facile synthesis of highly substituted pyridinium salts through the annulation of enamines with alkynes is reported herein. A Ag2 CO3 /HNTf2 synergistically acting catalyst system was developed and used in a condensation reaction between carbonyl substrates and propargylamine to afford structurally diverse pyridinium salts. A mechanistic investigation shows that this one-pot transformation proceeded via selective 6-endo-dig cyclization of the in situ generated propargylenamine and protonolysis of the resulting vinyl-silver intermediate. The reaction conditions are mild, and the substrate scope is broad. During the cyclization, an unusual inversion of the normal reactivity of α,ß-unsaturated carbonyl systems was observed.

Constructing Integrative ceRNA Networks and Finding Prognostic Biomarkers in Renal Cell Carcinoma.

Inspired by a newly discovered gene regulation mechanism known as competing endogenous RNA (ceRNA) interactions, several computational methods have been proposed to generate ceRNA networks. However, most of these methods have focused on deriving restricted types of ceRNA interactions such as lncRNA-miRNA-mRNA interactions. Competition for miRNA-binding occurs not only between lncRNAs and mRNAs but also between lncRNAs or between mRNAs. Furthermore, a large number of pseudogenes also act as ceRNAs, thereby regulate other genes. In this study, we developed a general method for constructing integrative networks of all possible interactions of ceRNAs in renal cell carcinoma (RCC). From the ceRNA networks we derived potential prognostic biomarkers, each of which is a triplet of two ceRNAs and miRNA (i.e., ceRNA-miRNA-ceRNA). Interestingly, some prognostic ceRNA triplets do not include mRNA at all, and consist of two non-coding RNAs and miRNA, which have been rarely known so far. Comparison of the prognostic ceRNA triplets to known prognostic genes in RCC showed that the triplets have a better predictive power of survival rates than the known prognostic genes. Our approach will help us construct integrative networks of ceRNAs of all types and find new potential prognostic biomarkers in cancer.

Constructing a Cancer Patient-Specific Network Based on Second-Order Partial Correlations of Gene Expression and DNA Methylation.

Typically patient-specific gene networks are constructed with gene expression data only. Such networks cannot distinguish direct gene interactions from indirect interactions via others such as the effect of epigenetic events to gene activity. There is an increasing evidence of inter-individual variations not only in gene expression but also in epigenetic events such as DNA methylation. In this paper we propose a new method for constructing a cancer patient-specific gene correlation network using both gene expression and DNA methylation data. We derive a patient-specific network from differential second-order partial correlations of gene expression and DNA methylation between normal samples and the patient sample. The network represents direct interactions between genes by controlling the effect of DNA methylation. Using this method, we constructed 4,000 patient-specific networks for 10 types of cancer. The networks are highly effective in classifying different types of cancer and in deriving potential prognostic gene pairs. In particular, potential prognostic gene pairs derived from the networks were powerful in predicting the survival time of cancer patients. This approach will help identify patient-specific gene correlations and predict prognosis of cancer patients.

Evolution of a Strategy for Concise Enantioselective Total Synthesis of the Salinosporamide Family of Natural Products.

Our first strategy for rapidly accessing pyrrolidinone cores of salinosporamides involved combined use of memory of chirality and dynamic kinetic resolution principles in aldol reactions of the serine-derived 5-oxazolidinone substrate, which was ultimately unsuccessful with respect to enantioselectivity. This failure led us to the revised strategy. The influence of the stereocenter in 5-oxazolidinone enabled selective installation of the C-2 stereocenter. The intramolecular aldol reaction of the C-2 stereodefined aldol substrate was successful. An unexpected hydrolytic dynamic kinetic resolution was observed in hydrolyses of the bicyclic aldol products. This unprecedented substrate-driven hydrolytic dynamic kinetic resolution was utilized in preparing the pyrrolidinone core with excellent efficiency. Through this strategy, the concise total syntheses of salinosporamides A and B as well as cinnabaramides A, E, and F were achieved with high selectivity.

Association between oral health and frailty: results from the Korea National Health and Nutrition Examination Survey.

BACKGROUND: Previous research has suggested that poor oral health is positively associated with frailty. The objective of this study was to explore associations of key oral diseases (periodontal disease, tooth loss), and oral hygiene and management behaviors with the level of frailty in community-dwelling older Korean adults using national representative survey data. METHODS: This study used cross-sectional, 6th and 7th Korea National Health and Nutrition Examination Survey (KNHANES VI, VII) data. Adults aged 50+ years were included. Frailty was measured using frailty phenotype (FP) and frailty index (FI). FP was determined using five frailty criteria, i.e., weight loss, weakness, exhaustion, slowness, or low physical activity, and the level of frailty was classified with the number of criteria present (robust, none; pre-frail, 1-2; frail, 3+). FI was determined using a 44-item FI constructed according to a standard protocol, and the level of frailty was classified as robust (FI: ≤ 0.08), pre-frail (FI: 0.08-0.25), and frail (FI: ≥ 0.25). Multiple ordinal regression analyses were conducted with each type of frailty as the outcome variable. Independent variables of interest were the periodontal status, number of teeth, and practices on oral hygiene and management. Analyses were additionally adjusted for participants' socioeconomic, diet, and behavioral characteristics. RESULTS: The prevalence of frailty was 4.38% according to the FP classification (n = 4156), 10.74% according to the FI classification (n = 15,073). In the final adjusted model, having more teeth and brushing after all three meals were significantly associated with lower odds of being more frail (in both frailty models); no significant association was observed between periodontal disease and frailty. CONCLUSIONS: Findings from this study show having more teeth and practicing adequate brushing are significantly associated with frailty. Due to limitations of the study design, well-designed longitudinal studies are needed to confirm these findings.

Exercise-induced piezoelectric stimulation for cartilage regeneration in rabbits.

More than 32.5 million American adults suffer from osteoarthritis, and current treatments including pain medicines and anti-inflammatory drugs only alleviate symptoms but do not cure the disease. Here, we have demonstrated that a biodegradable piezoelectric poly(L-lactic acid) (PLLA) nanofiber scaffold under applied force or joint load could act as a battery-less electrical stimulator to promote chondrogenesis and cartilage regeneration. The PLLA scaffold under applied force or joint load generated a controllable piezoelectric charge, which promoted extracellular protein adsorption, facilitated cell migration or recruitment, induced endogenous TGF-ß via calcium signaling pathway, and improved chondrogenesis and cartilage regeneration both in vitro and in vivo. Rabbits with critical-sized osteochondral defects receiving the piezoelectric scaffold and exercise treatment experienced hyaline-cartilage regeneration and completely healed cartilage with abundant chondrocytes and type II collagen after 1 to 2 months of exercise (2 to 3 months after surgery including 1 month of recovery before exercise), whereas rabbits treated with nonpiezoelectric scaffold and exercise treatment had unfilled defect and limited healing. The approach of combining biodegradable piezoelectric tissue scaffolds with controlled mechanical activation (via physical exercise) may therefore be useful for the treatment of osteoarthritis and is potentially applicable to regenerating other injured tissues.

Cation Composition-Dependent Device Performance and Positive Bias Instability of Self-Aligned Oxide Semiconductor Thin-Film Transistors: Including Oxygen and Hydrogen Effect.

Amorphous oxide semiconductor transistors control the illuminance of pixels in an ecosystem of displays from large-screen TVs to wearable devices. To satisfy application-specific requirements, oxide semiconductor transistors of various cation compositions have been explored. However, a comprehensive study has not been carried out where the influence of cation composition, oxygen, and hydrogen on device characteristics and stability is systematically quantified, using commercial-grade process technology. In this study, we fabricate self-aligned top-gate structure thin-film transistors with three oxide semiconductor materials, InGaZnO (In/Ga/Zn = 1:1:1), In-rich InGaZnO, and InZnO, having mobility values of 10, 27, and 40 cm2/V·s, respectively. Combinations of varied amounts of oxygen and hydrogen are incorporated into each transistor by controlling the fabrication process to study the effect of these gaseous elements on the physical nature of the channel material. Electrons can be captured by peroxy linkage (O22-) or undercoordinated In (In* to become In+), which are manifested in the extracted subgap density-of-states profile and first-principles calculations. Energy difference between electron-trapped In+ and O22- σ* is the smallest for IGZO, and In+-O22- annihilation occurs by electron excitation from the subgap In+ state to the O22- σ*. Furthermore, characteristic time constants during positive bias stress and recovery reveal the various microscopic physical phenomena within the transistor structure between different cation compositions.

Synthesis of Bridged Oxabicycles via Cascade Reactions involving O-Acyloxocarbenium Ion Intermediates.

Compared to related electrophilic species, O-acyloxocarbenium ions (AOIs) have been much less utilized in organic synthesis due to the lack of an efficient formation method. Here, we present a facile and simple approach for the generation of AOI from ester and acetal groups. Based on our AOI system with a pendant nucleophile, we obtained a unique bridged bicyclic system via an epoxonium-like transition state. The proposed mechanism is based on experimental and computational studies.

Pseudoelasticity of SrNi2P2 Micropillar via Double Lattice Collapse and Expansion.

The maximum recoverable strain of most crystalline solids is less than 1% because plastic deformation or fracture usually occurs at a small strain. In this work, we show that a SrNi2P2 micropillar exhibits pseudoelasticity with a large maximum recoverable strain of ∼14% under uniaxial compression via unique reversible structural transformation, double lattice collapse-expansion that is repeatable under cyclic loading. Its high yield strength (∼3.8 ± 0.5 GPa) and large maximum recoverable strain bring out the ultrahigh modulus of resilience (∼146 ± 19 MJ/m3), a few orders of magnitude higher than that of most engineering materials. The double lattice collapse-expansion mechanism shows stress-strain behaviors similar to that of conventional shape-memory alloys, such as hysteresis and thermo-mechanical actuation, even though the structural changes involved are completely different. Our work suggests that the discovery of a new class of high-performance ThCr2Si2-structured materials will open new research opportunities in the field of pseudoelasticity.

Targeted delivery of mPGES-1 inhibitors to macrophages via the folate receptor-ß for inflammatory pain.

Activated macrophages overexpress the folate receptor ß (FR-ß) that can be used for targeted delivery of drugs conjugated to folic acid. FR-expressing macrophages contribute to arthritis progression by secreting prostaglandin E2 (PGE2). Non-steroidal anti-inflammatory drugs (NSAIDs) block PGs and thromboxane by inhibiting the cyclooxygenase (COX) enzymes and are used for chronic pain and inflammation despite their well-known toxicity. New NSAIDs target an enzyme downstream of COXs, microsomal prostaglandin E synthase-1 (mPGES-1). Inhibition of mPGES-1 in inflammatory macrophages promises to retain NSAID efficacy while limiting toxicity. We conjugated a potent mPGES-1 inhibitor, MK-7285, to folate, but the construct released the drug inefficiently. Folate conjugation to the primary alcohol of MK-7285 improved the construct's stability and the release of free drug. Surprisingly, the drug-folate conjugate potentiated PGE2 in FR-positive KB cells, and reduced PGE2 in macrophages independently of the FR. Folate conjugation of NSAIDs is not an optimal strategy for targeting of macrophages.

Memory of Chirality in the Asymmetric Synthesis of Piperidines with Vicinal Stereocenters by Intramolecular Sn2' Reaction.

Intramolecular Sn2' cyclization of α-amino ester enolates provided piperidine derivatives with vicinal quaternary-tertiary stereocenters with excellent diastereo- and enantioselectivity via memory of chirality and the Thorpe-Ingold effect. DFT calculations provided a mechanistic rationale for the increase in chirality preservation via the Thorpe-Ingold effect. This new method has the potential to be integrated into concise asymmetric synthesis of bioactive molecules containing multisubstituted piperidine moieties.