Sanglifehrin A mitigates multi-organ fibrosis by targeting the collagen chaperone cyclophilin B.

Pathological deposition and crosslinking of collagen type I by activated myofibroblasts drives progressive tissue fibrosis. Therapies that inhibit collagen synthesis have potential as anti-fibrotic agents. We identify the collagen chaperone cyclophilin B as a major cellular target of the natural product sanglifehrin A (SfA) using photo-affinity labeling and chemical proteomics. Mechanistically, SfA inhibits and induces the secretion of cyclophilin B from the endoplasmic reticulum (ER) and prevents TGF-ß1-activated myofibroblasts from synthesizing and secreting collagen type I in vitro, without inducing ER stress, affecting collagen type I mRNA transcription, myofibroblast migration, contractility, or TGF-ß1 signaling. In vivo, SfA induced cyclophilin B secretion in preclinical models of fibrosis, thereby inhibiting collagen synthesis from fibrotic fibroblasts and mitigating the development of lung and skin fibrosis in mice. Ex vivo, SfA induces cyclophilin B secretion and inhibits collagen type I secretion from fibrotic human lung fibroblasts and samples from patients with idiopathic pulmonary fibrosis (IPF). Taken together, we provide chemical, molecular, functional, and translational evidence for demonstrating direct anti-fibrotic activities of SfA in preclinical and human ex vivo fibrotic models. Our results identify the cellular target of SfA, the collagen chaperone cyclophilin B, as a mechanistic target for the treatment of organ fibrosis.

The cyclimids: Degron-inspired cereblon binders for targeted protein degradation.

Cereblon (CRBN) is an E3 ligase substrate adapter widely exploited for targeted protein degradation (TPD) strategies. However, achieving efficient and selective target degradation is a preeminent challenge with ligands that engage CRBN. Here, we report that the cyclimids, ligands derived from the C-terminal cyclic imide degrons of CRBN, exhibit distinct modes of interaction with CRBN and offer a facile approach for developing potent and selective bifunctional degraders. Quantitative TR-FRET-based characterization of 60 cyclimid degraders in binary and ternary complexes across different substrates revealed that ternary complex binding affinities correlated strongly with cellular degradation efficiency. Our studies establish the unique properties of the cyclimids as versatile warheads in TPD and a systematic biochemical approach for quantifying ternary complex formation to predict their cellular degradation activity, which together will accelerate the development of ligands that engage CRBN.

A Versatile Isocyanate-Mediated Strategy for Appending Chemical Tags onto Drug-Like Small Molecules.

Target identification studies are a major hurdle in probe and drug discovery pipelines due to the need to chemically modify small molecules of interest, which can be time intensive and have low throughput. Here, we describe a versatile and scalable method for attaching chemical moieties to a small molecule, isocyanate-mediated chemical tagging (IMCT). By preparation of a template resin with an isocyanate capture group and a cleavable linker, nucleophilic groups on small molecules can be modified with an enforced one-to-one stoichiometry. We demonstrate a small molecule substrate scope that includes primary and secondary amines, thiols, phenols, benzyl alcohols, and primary alcohols. Cheminformatic analyses predict that IMCT is reactive with more than 25% of lead-like compounds in publicly available databases. To demonstrate that the method can produce biologically active molecules, we generated FKBP12 photoaffinity labeling (PAL) compounds with a wide range of affinities and showed that purified and crude cleavage products can bind to and label FKBP12. This method could be used to rapidly modify small molecules for many applications, including the synthesis of PAL probes, fluorescence polarization probes, pull-down probes, and degraders.

Sanglifehrin A mitigates multi-organ fibrosis in vivo by inducing secretion of the collagen chaperone cyclophilin B.

Pathological deposition and crosslinking of collagen type I by activated myofibroblasts drives progressive tissue fibrosis. Therapies that inhibit collagen synthesis by myofibroblasts have clinical potential as anti-fibrotic agents. Lysine hydroxylation by the prolyl-3-hydroxylase complex, comprised of cartilage associated protein, prolyl 3-hydroxylase 1, and cyclophilin B, is essential for collagen type I crosslinking and formation of stable fibers. Here, we identify the collagen chaperone cyclophilin B as a major cellular target of the macrocyclic natural product sanglifehrin A (SfA) using photo-affinity labeling and chemical proteomics. Our studies reveal a unique mechanism of action in which SfA binding to cyclophilin B in the endoplasmic reticulum (ER) induces the secretion of cyclophilin B to the extracellular space, preventing TGF-ß1-activated myofibroblasts from synthesizing collagen type I in vitro without inhibiting collagen type I mRNA transcription or inducing ER stress. In addition, SfA prevents collagen type I secretion without affecting myofibroblast contractility or TGF-ß1 signaling. In vivo, we provide chemical, molecular, functional, and translational evidence that SfA mitigates the development of lung and skin fibrosis in mouse models by inducing cyclophilin B secretion, thereby inhibiting collagen synthesis from fibrotic fibroblasts in vivo . Consistent with these findings in preclinical models, SfA reduces collagen type I secretion from fibrotic human lung fibroblasts and precision cut lung slices from patients with idiopathic pulmonary fibrosis, a fatal fibrotic lung disease with limited therapeutic options. Our results identify the primary liganded target of SfA in cells, the collagen chaperone cyclophilin B, as a new mechanistic target for the treatment of organ fibrosis.

Enantioselective Synthesis and Biological Evaluation of Sanglifehrin†A and B and Analogs.

Sanglifehrin A and B are immunosuppressive macrocyclic natural products endowed with and differentiated by a unique spirocyclic lactam. Herein, we report an enantioselective total synthesis and biological evaluation of sanglifehrin A and B and analogs. Access to the spirocyclic lactam was achieved through convergent assembly of a key pyranone intermediate followed by a stereo-controlled spirocyclization. The 22-membered macrocyclic core was synthesized by ring-closing metathesis in the presence of 2,6-bis(trifluoromethyl) benzeneboronic acid (BFBB). The spirocyclic lactam and macrocycle fragments were united by a Stille coupling to furnish sanglifehrin A and B. Additional sanglifehrin B analogs with variation at the C40 position were additionally prepared. Biological evaluation revealed that the 2-CF3 analog of sanglifehrin B exhibited higher anti-proliferative activity than the natural products sanglifehrin A and B in Jurkat cells. Both natural products induced higher-order homodimerization of cyclophilin A (CypA), but only sanglifehrin A promoted CypA complexation with inosine-5'-monophosphate dehydrogenase 2 (IMPDH2). The synthesis reported herein will enable further evaluation of the spirolactam and its contribution to sanglifehrin-dependent immunosuppressive activity.

Enantioselective Total Synthesis of the Putative Biosynthetic Intermediate Ambruticin†J.

The family of anti-fungal natural products known as the ambruticins are structurally distinguished by a pair of pyran rings adorning a divinylcyclopropane core. Previous characterization of their biosynthesis, including the expression of a genetically modified producing organism, revealed that the polyketide synthase pathway proceeds via a diol intermediate, known as ambruticin J. Herein, we report the first enantioselective total synthesis of the putative PKS product, ambruticin J, according to a triply convergent synthetic route featuring a Suzuki-Miyaura cross-coupling and a Julia-Kocienski olefination for fragment assembly. This synthesis takes advantage of synthetic methodology previously developed by our laboratory for the stereoselective generation of the trisubstituted cyclopropyl linchpin.

The Effect of Positive Emotion and Interpersonal Relationships to Adaptation of School Life on High School Athletic Class Students.

BACKGROUND: Adaption for school life is important for all students. As for athletic students, since they need to cope with schoolwork and extensive training, adaption for school life could be very challenging. Taking this into consideration, the purpose of this study was to explore the factors which may help high school athletic students' adaption of school life. Owing to this, the study explored previous researches and proposed four hypotheses: the first two hypotheses proposed that athletes' positive emotion will have positive impacts on both their interpersonal relationships and adaption of school life; the third hypothesis suggests that athletes' interpersonal relationships will have positive impacts on their adaption of school life and the fourth hypothesis suggested that interpersonal relationships play a mediating role among the positive emotion's effect on adaption of school life. METHODS: A total of 800 structured questionnaires were distributed to eleven high schools with athletic class students for data collection with a valid return rate of 90.6%. Structural equation modelling was used to test the relationship among them. RESULTS: The result showed that positive emotion (ß = 0.72, p < 0.05) and interpersonal relationships (ß = 0.34, p < 0.05) had positive impacts on students' adaption of school life with a predictive power of 68%. In addition, positive emotion also affected students' school life adaption through interpersonal relationships. CONCLUSION: The study confirmed the positive emotion can have significant influences on student athletes' interpersonal relationships and school life adaption. IMPLICATIONS: According to our findings, we suggest to encourage and promote athletes' positive emotions so to help them have better interpersonal relationships and school life adaption.

A Binding Site Hotspot Map of the FKBP12-Rapamycin-FRB Ternary Complex by Photoaffinity Labeling and Mass Spectrometry-Based Proteomics.

Structural characterization of small molecule binding site hotspots within the global proteome is uniquely enabled by photoaffinity labeling (PAL) coupled with chemical enrichment and unbiased analysis by mass spectrometry (MS). MS-based binding site maps provide structural resolution of interaction sites in conjunction with identification of target proteins. However, binding site hotspot mapping has been confined to relatively simple small molecules to date; extension to more complex compounds would enable the structural definition of new binding modes in the proteome. Here, we extend PAL and MS methods to derive a binding site hotspot map for the immunosuppressant rapamycin, a complex macrocyclic natural product that forms a ternary complex with the proteins FKBP12 and FRB. Photo-rapamycin was developed as a diazirine-based PAL probe for rapamycin, and the FKBP12-photo-rapamycin-FRB ternary complex formed readily in vitro. Photoirradiation, digestion, and MS analysis of the ternary complex revealed a McLafferty rearrangement product of photo-rapamycin conjugated to specific surfaces on FKBP12 and FRB. Molecular modeling based on the binding site map revealed two distinct conformations of complex-bound photo-rapamycin, providing a 5.0 Å distance constraint between the conjugated residues and the diazirine carbon and a 9.0 Å labeling radius for the diazirine upon photoactivation. These measurements may be broadly useful in the interpretation of binding site measurements from PAL. Thus, in characterizing the ternary complex of photo-rapamycin by MS, we applied binding site hotspot mapping to a macrocyclic natural product and extracted precise structural measurements for interpretation of PAL products that may enable the discovery of new binding sites in the "undruggable" proteome.

Conformation-guided analogue design identifies potential antimalarial compounds through inhibition of mitochondrial respiration.

The synthesis of a 2-methyl-substituted analogue of the natural product, neopeltolide, is reported in an effort to analyze the importance of molecular conformation and ligand-target interactions in relation to biological activity. The methyl substitution was incorporated via highly diastereoselective ester enolate alkylation of a late-stage intermediate. Coupling of the oxazole sidechain provided 2-methyl-neopeltolide and synthetic neopeltolide via total synthesis. The substitution was shown to maintain the conformational preferences of its biologically active parent compound through computer modeling and NMR studies. Both compounds were shown to be potential antimalarial compounds through the inhibition of mitochondrial respiration in P. falciparum parasites.

In Situ Investigation of Defect-Free Copper Nanowire Growth.

The fabrication and placement of high purity nanometals, such as one-dimensional copper (Cu) nanowires, for interconnection in integrated devices have been among the most important technological developments in recent years. Structural stability and oxidation prevention have been the key issues, and the defect control in Cu nanowire growth has been found to be important. Here, we report the synthesis of defect-free single-crystalline Cu nanowires by controlling the surface-assisted heterogeneous nucleation of Cu atomic layering on the graphite-like loop of an amorphous carbon (a-C) lacey film surface. Without a metal-catalyst or induced defects, the high quality Cu nanowires formed with high aspect ratio and high growth rate of 578 nm/s. The dynamic study of the growth of heterogeneous nanowires was conducted in situ with a high-resolution transmission electron microscope. The study illuminates the new mechanism by heterogeneous nucleation control and laying the groundwork for better understanding of heterosurface-assisted nucleation of defect-free Cu nanowire on a-C lacey film.

Direct Observation of Dual-Filament Switching Behaviors in Ta2 O5 -Based Memristors.

The Forming phenomenon is observed via in situ transmission electron microscopy in the Ag/Ta2 O5 /Pt system. The device is switched to a low-resistance state as the dual filament is connected to the electrodes. The results of energy dispersive spectrometer and electron energy loss spectroscopy analyses demonstrate that the filament is composed by a stack of oxygen vacancies and Ag metal.

Nickel/Platinum Dual Silicide Axial Nanowire Heterostructures with Excellent Photosensor Applications.

Transition metal silicide nanowires (NWs) have attracted increasing attention as they possess advantages of both silicon NWs and transition metals. Over the past years, there have been reported with efforts on one silicide in a single silicon NW. However, the research on multicomponent silicides in a single silicon NW is still rare, leading to limited functionalities. In this work, we successfully fabricated ß-Pt2Si/Si/θ-Ni2Si, ß-Pt2Si/θ-Ni2Si, and Pt, Ni, and Si ternary phase axial NW heterostructures through solid state reactions at 650 °C. Using in situ transmission electron microscope (in situ TEM), the growth mechanism of silicide NW heterostructures and the diffusion behaviors of transition metals were systematically studied. Spherical aberration corrected scanning transmission electron microscope (Cs-corrected STEM) equipped with energy dispersive spectroscopy (EDS) was used to analyze the phase structure and composition of silicide NW heterostructures. Moreover, electrical and photon sensing properties for the silicide nanowire heterostructures demonstrated promising applications in nano-optoeletronic devices. We found that Ni, Pt, and Si ternary phase nanowire heterostructures have an excellent infrared light sensing property which is absent in bulk Ni2Si or Pt2Si. The above results would benefit the further understanding of heterostructured nano materials.

Total Synthesis and Structural Reassignment of Lyngbyaloside C Highlighted by Intermolecular Ketene Esterification.

Lyngbyaloside C, a classic macrolide, isolated from Lyngbya bouilloni, has shown moderate anticancer activity against several cancer cell lines. Here, we report the first total synthesis and stereochemical configuration reassignment of lyngbyaloside C. The synthesis highlights a one-pot intermolecular ketene esterification reaction to form the crucial tertiary ester and tetrahydropyran. In addition, a novel and concise synthetic pathway towards the 1,3-syn secondary, tertiary diol fragment is described using a regio- and stereospecific electrophilic ether transfer reaction.

Pharmacology and Clinical Effect of Platonin, a Cyanine Photosensitizing Dye: Potential Molecular Targets.

Platonin, a photosensitizing dye, is known to possess antioxidant and anti-inflammatory activity. Platonin has been used to treat trauma, ulcers and some acute inflammations and it also reported to improve blood circulation and reduce mortality in endotoxin-induced rat models. Our previous studies established that platonin suppresses the lipopolysaccharides (LPS)-induced inflammatory cytokines, including interleukin-1ß (IL-1ß-+), IL-6, tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS). Nuclear factor-kB (NF-kB) and activator protein-1 (AP-1) transcription factors are reported to be essential in mediating the endotoxin-induced production of inflammatory molecules. In vivo studies from our groups revealed that platonin has potential effects on inhibiting pyrogen release, tissue damage and ischemia during heatstroke, ischemia reperfusion injury in lungs and also improve the survival of skin allografts in rats. Clinically, this compound has been proven to cure juvenile rheumatoid arthritis (JRA) and polyarteritis nodosa (PN). In this review, we summarize the pharmacological and clinical effects of platonin via describing the potential molecular mechanism of regulation of inflammatory molecules of mitogen-activated protein kinases (MAPKs), including extracellular regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38 MAPK and also NF-kB activation. Moreover, this paper discusses the signaling pathways expedited by NF-kB, AP-1, MAPKs and NO/NOS, these all have been reflected in inflammatory processes, and could be the encouraging molecular targets for the design of pharmaceutical drugs targeting antiinflammatory therapy.

Improved performance of CuInS2 quantum dot-sensitized solar cells based on a multilayered architecture.

This article describes a CuInS2 quantum dot (QD)-sensitized solar cell (QDSSC) with a multilayered architecture and a cascaded energy-gap structure fabricated using a successive ionic-layer adsorption and reaction process. We initially used different metal chalcogenides as interfacial buffer layers to improve unmatched band alignments between the TiO2 and CuInS2 QD sensitizers. In this design, the photovoltaic performance, in terms of the short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and power conversion efficiency (PCE), was significantly improved. Both JSC and VOC were improved in CuInS2-based QDSSCs in the presence of interfacial buffer layers because of proper band alignment across the heterointerface and the negative band edge movement of TiO2. The PCE of CuInS2-based QDSSCs containing In2Se3 interfacial buffer layers was 1.35%, with JSC=5.83 mA/cm2, VOC=595 mV, and FF=39.0%. We also examined the use of alternative CdS and CdSe hybrid-sensitized layers, which were sequentially deposited onto the In2Se3/CuInS2 configuration for creating favorable cascaded energy-gap structures. Both JSC (11.3 mA cm(-2)) and FF (47.3%) for the CuInS2/CdSe hybrid-sensitized cells were higher than those for CuInS2-based cells (JSC=5.83 mA cm(-2) and FF=39.0%). In addition, the hybrid-sensitized cells had PCEs that were 1.3 times those of cells containing identically pretreated In2Se3 interfacial buffer layers. Additionally, we determined that ZnSe served as a good passivation layer on the surface of CuInS2/CdSe hybrid-sensitized QDs, prevented current leakage from the QDs to electrolytes, and lowered interfacial charge recombination. Under simulated illumination (AM 1.5, 100 mW cm(-2)), multilayered QDSSCs with distinct architectures delivered a maximum external quantum efficiency of 80% at 500 nm and a maximum PCE of 4.55%, approximately 9 times that of QDSSCs fabricated with pristine CuInS2.

Melatonin attenuates kainic acid-induced neurotoxicity in mouse hippocampus via inhibition of autophagy and α-synuclein aggregation.

In this study, the protective effect of melatonin on kainic acid (KA)-induced neurotoxicity involving autophagy and α-synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3-II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA-induced LC3-II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA-induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro-apoptotic role of autophagy in the KA-induced neurotoxicity. Nevertheless, KA-induced α-synuclein aggregation was not affected in the Atg7 siRNA-transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA-induced autophagy-lysosomal activation by reducing KA-induced increases in LC3-II, lysosomal-associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA-induced mitochondria loss was prevented in the melatonin-treated mice. At the same time, melatonin reduced KA-increased HO-1 levels and α-synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α-synuclein monomers and aggregates. The anti-apoptotic effect of melatonin was demonstrated by attenuating KA-induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA-induced neurotoxicity may be mediated by autophagy and α-synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA-induced autophagy and a subsequent mitochondrial loss as well as reducing α-synuclein aggregation by enhancing α-synuclein ubiquitination in the CNS.