Controllable and Reversible Assembly of Nanofiber from Natural Macromolecules via Protonation and Deprotonation.

Nanofiber is the critical building block for many biological systems to perform various functions. Artificial assembly of molecules into nanofibers in a controllable and reversible manner will create "smart" functions to mimic those of their natural analogues and fabricate new functional materials, but remains an open challenge especially for nature macromolecules. Herein, the controllable and reversible assembly of nanofiber (CSNF) from natural macromolecules with oppositely charged groups are successfully realized by protonation and deprotonation of charged groups. By controlling the electrostatic interaction via protonation and deprotonation, the size and morphology of the assembled nanostructures can be precisely controlled. A strong electrostatic interaction contributes to large nanofiber with high strength, while poor electrostatic interaction produces finer nanofiber or nanoparticle. And especially, the assembly, disassembly, and reassembly of the nanofiber occurs reversibly through protonation and deprotonation, thereby paving a new way for precisely controlling the assembly process and structure of nanofiber. The reversible assembly allows the nanostructure to dynamically reorganize in response to subtle perturbation of environment. The as-prepared CSNF is mechanical strong and can be used as a nano building block to fabricate high-strength film, wire, and straw. This study offers many opportunities for the biomimetic synthesis of new functional materials.

Stabilizing *CO2 Intermediates at the Acidic Interface using Molecularly Dispersed Cobalt Phthalocyanine as Catalysts for CO2 Reduction.

CO2 electroreduction (CO2 R) operating in acidic media circumvents the problems of carbonate formation and CO2 crossover in neutral/alkaline electrolyzers. Alkali cations have been universally recognized as indispensable components for acidic CO2 R, while they cause the inevitable issue of salt precipitation. It is therefore desirable to realize alkali-cation-free CO2 R in pure acid. However, without alkali cations, stabilizing *CO2 intermediates by catalyst itself at the acidic interface poses as a challenge. Herein, we first demonstrate that a carbon nanotube-supported molecularly dispersed cobalt phthalocyanine (CoPc@CNT) catalyst provides the Co single-atom active site with energetically localized d states to strengthen the adsorbate-surface interactions, which stabilizes *CO2 intermediates at the acidic interface (pH=1). As a result, we realize CO2 conversion to CO in pure acid with a faradaic efficiency of 60 % at pH=2 in flow cell. Furthermore, CO2 is successfully converted in cation exchanged membrane-based electrode assembly with a faradaic efficiency of 73 %. For CoPc@CNT, acidic conditions also promote the intrinsic activity of CO2 R compared to alkaline conditions, since the potential-limiting step, *CO2 to *COOH, is pH-dependent. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts and devices for acidic CO2 R.

Dispersed Nickel Phthalocyanine Molecules on Carbon Nanotubes as Cathode Catalysts for Li-CO2 Batteries.

The Li-CO2 battery has great potential for both CO2 utilization and energy storage, but its practical application is limited by low energy efficiency and short cycle life. Efficient cathode catalysts are needed to address this issue. Herein, this work reports on molecularly dispersed electrocatalysts (MDEs) of nickel phthalocyanine (NiPc) anchored on carbon nanotubes (CNTs) as the cathode catalyst for Li-CO2 batteries. The dispersed NiPc molecules efficiently catalyze CO2 reduction, while the conductive and porous CNTs networks facilitate CO2 evolution reaction, leading to enhanced discharging and charging performance compared to the NiPc and CNTs mixture. Octa-cyano substitution on NiPc (NiPc-CN) further enhances the interaction between the molecule and CNTs, resulting in better cycling stability. The Li-CO2 battery with the NiPc-CN MDE cathode shows a high discharge voltage of 2.72 V and a small discharging-charging potential gap of 1.4 V, and can work stably for over 120 cycles. The reversibility of the cathode is confirmed by experimental characterizations. This work lays a foundation for the development of molecular catalysts for Li-CO2 battery cathodes.

Synergistic Chemical Synthesis and Self-Assembly Lead to Three-Dimensional b-Oriented MFI Superstructures with Selective Adsorption and Luminescence Properties.

Higher-order organization of inorganic nanoparticles with hierarchical architectures and tailored functionality is crucial in the nanofabrication of advanced materials. Here we demonstrate that three-dimensional b-oriented MFI superstructures can be organized by synergistic chemical synthesis and self-assembly. The organization is accomplished by vapor treatment of tetrapropylammonium hydroxide (TPAOH)-coated inorganic/bacterial cellulose scaffolds. TPA+ acts to direct nucleation and to mediate crystal morphology leading to oriented assembly of MFI crystals along crystallographic b-axis, whereas bacterial cellulose holds the oriented assembly together forming three-dimensional superstructures with macroporosity. Self-supporting monoliths of the macroporous MFI show outstanding selective adsorption for para-xylene and high adsorption capacity for volatile organic compounds. Incorporating luminescent molecules imparts the macroporous monoliths the new property of adsorption tunable luminescence that may act as an optical sensor indicating the level of adsorption. The current work opens a novel space for rational organization of hierarchical materials with tailored architectures and multifunctionality.

Effect of Tetrodotoxin Pellets in a Rat Model of Postherpetic Neuralgia.

Postherpetic neuralgia (PHN) is nerve pain caused by a reactivation of the varicella zoster virus. Medications are used to reduce PHN but their use is limited by serious side effects. Tetrodotoxin (TTX) is a latent neurotoxin that can block neuropathic pain, but its therapeutic index is only 3⁻5 times with intravenous or intramuscular injection. Therefore, we prepared oral TTX pellets and examined their effect in a rat model of PHN induced by resiniferatoxin (RTX). Oral TTX pellets were significantly effective at preventing RTX-induced mechanical and thermal allodynia, and similar to pregabalin. Moreover, oral administration of TTX pellets dose-dependently inhibited RTX-induced PHN compared with intramuscular administration of TTX injection. We also studied the pharmacokinetic profile of TTX pellets. Our results showed that the blood concentration of TTX reached a maximum plasma concentration (Cmax) at around 2 h, with an elimination half-life time (t1/2) of 3.23 ± 1.74 h after intragastric administration. The median lethal dose (LD50) of TTX pellets was 517.43 µg/kg via oral administration to rats, while the median effective dose (ED50) was approximately 5.85 µg/kg, and the therapeutic index was 88.45. Altogether, this has indicated that oral TTX pellets greatly enhance safety when compared with TTX injection.

The role of nuclear factor E2-Related factor 2 and uncoupling protein 2 in glutathione metabolism: Evidence from an in vivo gene knockout study.

Nuclear factor E2-related factor 2 (NRF2) and uncoupling protein 2 (UCP2) are indicated to protect from oxidative stress. They also play roles in the homeostasis of glutathione. However, the detailed mechanisms are not well understood. In the present study, we found Nrf2-knockout (Nrf2-KO) mice exhibited altered glutathione homeostasis and reduced expression of various genes involved in GSH biosynthesis, regeneration, utilization and transport in the liver. Ucp2-knockout (Ucp2-KO) mice exhibited altered glutathione homeostasis in the liver, spleen and blood, as well as increased transcript of cystic fibrosis transmembrane conductance regulator in the liver, a protein capable of mediating glutathione efflux. Nrf2-Ucp2-double knockout (DKO) mice showed characteristics of both Nrf2-KO and Ucp2-KO mice. But no significant difference was observed in DKO mice when compared with Nrf2-KO or Ucp2-KO mice, except in blood glutathione levels. These data suggest that ablation of Nrf2 and Ucp2 leads to disrupted GSH balance, which could result from altered expression of genes involved in GSH metabolism. DKO may not evoke more severe oxidative stress than the single gene knockout.

Increased differentiation of Th22 cells in Hashimoto's thyroiditis.

As Th22 subsets are identified, their involvement in the pathogenesis of numerous autoimmune diseases has become apparent. In this study, we investigated differentiation of Th22 cells in the autoimmune thyroid diseases including Hashimoto's thyroiditis (HT) and Graves' disease (GD). Besides, we also explored the involvement of Th22 cells in an iodine-induced autoimmune thyroiditis (AIT) model (i.e., NOD.H-2(h4) mice). In HT patients, we showed the level of circulating Th22 cells correlated with the level of serum IL-22, and was significantly higher than in GD patients and healthy control subjects. Levels of serum IL-6, a major Th22 cell differentiation effector, were also higher in HT, and correlated with Th22 cells concentration. Peripheral blood mononuclear cells isolated from HT patients produced larger amounts of IL-6 in vitro than did those isolated from other groups. Furthermore, unlike those from GD patients, T lymphocytes from HT patients showed an enhanced differentiation in vitro into Th22 cells in the presence of recombinant IL-6 and TNF-α. In addition, levels of circulating Th22 cells and titers of thyroid peroxidase antibody were positively correlated in HT patients. In NOD.H-2(h4) mice, higher numbers of Th22 cells were observed in the spleens of the AIT group, while splenocytes of this group also produced larger amounts of IL-6 and IL-22 in vitro compared with the control. Intra-thyroid infiltrating IL-22+ lymphocytes were significantly increased in mice of the AIT group compared with the control. Our results indicate that Th22 cells may contribute to the pathogenesis of HT.

Halogenated retinoid derivatives as dual RARα and RXRα modulators for treating acute promyelocytic leukemia cells.

Acute promyelocytic leukemia (APL), a distinctive subtype of acute myeloid leukemia (AML), is characterized by the t(15; 17) translocation forming the PML-RARα fusion protein. Recent studies have revealed a crucial role of retinoid X receptor α (RXRα) in PML-RARα's tumorigenesis. This necessitates the development of dual RARα and RXRα targeting compounds for treating APL. Here, we developed a pair of brominated retinoid isomers, 5a and 5b, exhibiting RARα agonistic selectivity among the RAR subtypes and RXRα partial agonistic activities. In the treatment of APL cells, low doses (RARα activation range) of 5a and 5b degrade PML-RARα and strongly induce differentiation, while higher doses (RXRα activation range) induce G2/M arrest and apoptosis in both all-trans retinoic acid (ATRA)-sensitive and resistant cells. We replaced the bromine in 5a with chlorine or iodine to obtain compounds 7 or 8a. Interestingly, the chlorinated compound 7 tends to activate RXRα and induce G2/M arrest and apoptosis, while the iodinated compound 8a tends to activate RARα and induce differentiation. Together, our work underscores several advantages and characteristics of halogens in the rational design of RARα and RXRα ligands, offering three promising drug candidates for treating both ATRA-sensitive and resistant APL.

Isoniazid suppresses antioxidant response element activities and impairs adipogenesis in mouse and human preadipocytes.

Transcriptional signaling through the antioxidant response element (ARE), orchestrated by the Nuclear factor E2-related factor 2 (Nrf2), is a major cellular defense mechanism against oxidative or electrophilic stress. Here, we reported that isoniazid (INH), a widely used antitubercular drug, displays a substantial inhibitory property against ARE activities in diverse mouse and human cells. In 3T3-L1 preadipocytes, INH concentration-dependently suppressed the ARE-luciferase reporter activity and mRNA expression of various ARE-dependent antioxidant genes under basal and oxidative stressed conditions. In keeping with our previous findings that Nrf2-ARE plays a critical role in adipogenesis by regulating expression of CCAAT/enhancer-binding protein ß (C/EBPß) and peroxisome proliferator-activated receptor γ (PPARγ), suppression of ARE signaling by INH hampered adipogenic differentiation of 3T3-L1 cells and human adipose-derived stem cells (ADSCs). Following adipogenesis induced by hormonal cocktails, INH-treated 3T3-L1 cells and ADSCs displayed significantly reduced levels of lipid accumulation and attenuated expression of C/EBPα and PPARγ. Time-course studies in 3T3-L1 cells revealed that inhibition of adipogenesis by INH occurred in the early stage of terminal adipogenic differentiation, where reduced expression of C/EBPß and C/EBPδ was observed. To our knowledge, the present study is the first to demonstrate that INH suppresses ARE signaling and interrupts with the transcriptional network of adipogenesis, leading to impaired adipogenic differentiation. The inhibition of ARE signaling may be a potential underlying mechanism by which INH attenuates cellular antioxidant response contributing to various complications.

Divergent effects of sulforaphane on basal and glucose-stimulated insulin secretion in ß-cells: role of reactive oxygen species and induction of endogenous antioxidants.

PURPOSE: Oxidative stress is implicated in pancreatic ß-cell dysfunction, yet clinical outcomes of antioxidant therapies on diabetes are inconclusive. Since reactive oxygen species (ROS) can function as signaling intermediates for glucose-stimulated insulin secretion (GSIS), we hypothesize that exogenously boosting cellular antioxidant capacity dampens signaling ROS and GSIS. METHODS: To test the hypothesis, we formulated a mathematical model of redox homeostatic control circuit comprising known feedback and feedforward loops and validated model predictions with plant-derived antioxidant sulforaphane (SFN). RESULTS: SFN acutely (30-min treatment) stimulated basal insulin secretion in INS-1(832/13) cells and cultured mouse islets, which could be attributed to SFN-elicited ROS as N-acetylcysteine or glutathione ethyl ester suppressed SFN-stimulated insulin secretion. The mathematical model predicted an adapted redox state characteristic of strong induction of endogenous antioxidants but marginally increased ROS under prolonged SFN exposure, a state that attenuates rather than facilitates glucose-stimulated ROS and GSIS. We validated the prediction by demonstrating that although 24-h treatment of INS-1(832/13) cells with low, non-cytotoxic concentrations of SFN (2-10 µM) protected the cells from cytotoxicity by oxidative insult, it markedly suppressed insulin secretion stimulated by 20 mM glucose. CONCLUSIONS: Our study indicates that adaptive induction of endogenous antioxidants by exogenous antioxidants, albeit cytoprotective, inhibits GSIS in ß-cells.