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Supplementary methods and figure legends

Supplementary tables 1 and 2

Supplementary figures S1-S6

Anti-VEGF therapies benefit several cancer types, but drug resistance that limits therapeutic response can emerge. We generated cell lines from anti-VEGF–resistant tumor xenografts to investigate the mechanisms by which resistance develops. Of all tumor cells tested, only A431 (A431-V) epidermoid carcinoma cells developed partial resistance to the VEGF inhibitor aflibercept. Compared with the parental tumors, A431-V tumors secreted greater amounts of IL6 and exhibited higher levels of phospho-STAT3. Notably, combined blockade of IL6 receptor (IL6R) and VEGF resulted in enhanced activity against A431-V tumors. Similarly, inhibition of IL6R enhanced the antitumor effects of aflibercept in DU145 prostate tumor cells that displays high endogenous IL6R activity. In addition, post hoc stratification of data obtained from a clinical trial investigating aflibercept efficacy in ovarian cancer showed poorer survival in patients with high levels of circulating IL6. These results suggest that the activation of the IL6/STAT3 pathway in tumor cells may provide a survival advantage during anti-VEGF treatment, suggesting its utility as a source of response biomarkers and as a therapeutic target to heighten efficacious results. Cancer Res; 76(8); 2327–39. ©2016 AACR.

Mg2+ induced peptide hydrogels exhibit tunable stiffness, nanostructures and self-assembly of hMSC into multicellular spheroids.

Hydrogels are a class of biomaterials used in the field of tissue engineering and drug delivery. Many tissue engineering applications depend on the material properties of hydrogel scaffolds, such as mechanical stiffness, pore size, and interconnectivity. In this work, we describe the synthesis of peptide/polymer hybrid double-network (DN) hydrogels composed of supramolecular and covalent polymers. The DN hydrogels were prepared by combining the self-assembled pentafluorobenzyl diphenylalanyl aspartic acid (PFB-FFD) tripeptide for the first network and the polymeric PNIPAM-PEGDA copolymer for the second network. During this process, self-assembled peptide nanostructures are cross-linked to the polyacrylamide group in the polymer network through non-covalent interactions. The PNIPAM-PEGDA:PFB-FFD hydrogel exhibited higher mechanical stiffness (

Background CTLA4Ig is a dimeric fusion protein of the extracellular domain of cytotoxic T-lymphocyte protein 4 (CTLA4) and an Fc (Ig) fragment of human IgG1 that is approved for treating rheumatoid arthritis. However, CTLA4Ig may induce adverse effects. Developing a lesion-selective variant of CTLA4Ig may improve safety while maintaining the efficacy of the treatment. Methods We linked albumin to the N-terminus of CTLA4Ig (termed Alb-CTLA4Ig) via a substrate sequence of matrix metalloproteinase (MMP). The binding activities and the biological activities of Alb-CTLA4Ig before and after MMP digestion were analyzed by a cell-based ELISA and an in vitro Jurkat T cell activation assay. The efficacy and safety of Alb-CTLA4Ig in treating joint inflammation were tested in mouse collagen-induced arthritis. Results Alb-CTLA4Ig is stable and inactive under physiological conditions but can be fully activated by MMPs. The binding activity of nondigested Alb-CTLA4Ig was at least 10,000-fold weaker than that of MMP-digested Alb-CTLA4Ig. Nondigested Alb-CTLA4Ig was unable to inhibit Jurkat T cell activation, whereas MMP-digested Alb-CTLA4Ig was as potent as conventional CTLA4Ig in inhibiting the T cells. Alb-CTLA4Ig was converted to CTLA4Ig in the inflamed joints to treat mouse collagen-induced arthritis, showing similar efficacy to that of conventional CTLA4Ig. In contrast to conventional CTLA4Ig, Alb-CTLA4Ig did not inhibit the antimicrobial responses in the spleens of the treated mice. Conclusions Our study indicates that Alb-CTLA4Ig can be activated by MMPs to suppress tissue inflammation in situ. Thus, Alb-CTLA4Ig is a safe and effective treatment for collagen-induced arthritis in mice.

Background The antiviral resistance of cytomegalovirus (CMV) infections is associated with mutations in the CMV UL54 and UL97 gene regions and is a serious problem in immunocompromised patients. However, the molecular epidemiology of UL54 and UL97 in Taiwan is unclear. Methods We conducted a retrospective study of patients with CMV infections between January and December 2016 in two tertiary hospitals, one regional hospital in Taiwan. CMV DNAemia was confirmed by elevated CMV DNA titers. Then the regions of the UL54 and UL97 mutations were amplified by PCR and sequenced. Results Of 729 patients with CMV syndrome, 112 CMV DNAemia patients were enrolled. Twelve novel variants in UL54 (P342S, S384F, K434R, S673F, T754M, R778H, C814S, M827I, G878E, S880L, E888K, and S976N) and one novel variant in UL97 (M615T) were discovered. UL97 antiviral resistance mutations (L595S, M460I, and M460V) were found in four patients (3.6%). In the drug resistance strains, the mutation events occurred after 83–150 days of therapy, and drug resistance was also observed in these patients. The following high frequency variants were observed: D605E in UL97 and A885T, N898D, V355A, N685S, and A688V in UL54. Conclusion The results demonstrate that the positive rate of CMV DNAemia was 15.3% (112/729) among the patients with clinical CMV infection symptoms. The proportion of antiviral resistance CMV strains within CMV DNAemia patients was 3.6%. With the information of polymorphism incidence in the UL54 and UL97 patients from our study, determination of the genetic profile of UL54 and UL97 among immunocompromised populations with refractory CMV infection is recommended.

N-Cadherin is a transmembrane glycoprotein that plays a crucial role in the condensation of mesenchymal cells by enhancing cell-cell interactions during the process of chondrogenesis. The biophysical and biochemical signals can incite enhanced cell-cell contact which ultimately determines the fate of stem cells. The role of cadherin mimetic peptides on the differentiation of mesenchymal stem cells is obscure and must be explored in greater detail. In this study, we designed and synthesized a series of bioactive peptide sequences that mimic the EC-1 domain of the cadherin peptide sequence His-Ala-Val (HAV) motif. These peptide hydrogelators can self-assemble into stable supramolecular nanofibrous hydrogels at physiological pH in the presence of Fmoc-diphenylalanine (2) with tunable mechanical stiffness. Human mesenchymal stem cells (3A6) were encapsulated in N-cadherin mimetic peptide hydrogels to evaluate their role in stem cell differentiation and chondrogenesis. The results suggested that these peptide hydrogels are nontoxic to 3A6 cells and promoted chondrogenesis. Interestingly, 3A6 cells exposed to Fmoc-GGHAVDI (1d) peptide solution showed an enhanced expression level of chondrogenic specific marker collagen-II (Col-II) in comparison with other peptide sequences. In contrast, when 3A6 cells were encapsulated in the hydrogel blend (2/1c), the peptide sequence with flanking amino acid serine exhibited greater material stiffness with enhanced glycosaminoglycan (GAG) distribution and high expression levels of chondrogenic specific markers for the cartilage-specific matrix. This suggests that substrate stiffness and peptide sequences can influence stem cell differentiation. The hydrogel with the HAV motif with greater substrate stiffness (2/1c) can promote the chondrogenic differentiation of human mesenchymal stem cells which can be a promising candidate for 3D cell culture and stem cell-based cartilage regeneration therapies.

Synthetic bioactive aromatic peptide amphiphiles have been recognized as key elements of emerging biomedical strategies due to their biocompatibility, design flexibility, and functionality. Inspired by natural proteins, we synthesized two supramolecular materials of phenyl-capped Ile-Lys-Val-Ala-Val (Ben-IKVAV) and perfluorophenyl-capped Ile-Lys-Val-Ala-Val (PFB-IKVAV). We employed UV-vis absorption, fluorescence, circular dichroism, and Fourier-transform infrared spectroscopy to examine the driving force in the self-assembly of the newly discovered materials. It was found that both compounds exhibited ordered π-π interactions and secondary structures, especially PFB-IKVAV. The cytotoxicity of human mesenchymal stem cells (hMSCs) and cell differentiation studies was also performed. In addition, the immunofluorescent staining for neuronal-specific markers of MAP2 was 4.6 times (neural induction medium in the presence of PFB-IKVAV) that of the neural induction medium (control) on day 7. From analyzing the expression of neuronal-specific markers in hMSCs, it can be concluded that PFB-IKVAV may be a potential supramolecular biomaterial for biomedical applications.

The discovery of crown ethers and their unique interactions with ions make them play a key role in supramolecular chemistry. In this study, we have developed a new type of amphiphilic crown ether (DB18C6, DB24C8)-conjugated phenylalanine dipeptides for the gelation of water at physiological pH. We report here for the first time that the size of the crown ether controlled the morphology of the self-assembled nanostructures of the hydrogels, as well as their interactions with human mesenchymal stem cells (hMSCs; 3A6-RFP) and mouse fibroblasts (L929). For example, relative to its d-form and other crown sizes, DB18C6LFLF exhibited greater cell adhesion and was nontoxic towards hMSCs after culturing for 72 h. We hypothesize that the steric effect of the crown ether moiety in the assemblies has substantial influences on the morphology of the nanostructures and the cell-material response. Such distinct cell responses should be beneficial for the development of supramolecular biomaterials.

This work reports the synthesis of Au@Cu2O core@shell nanocrystals with controllable shell thicknesses and demonstrates their use as the dual-functional catalyst that can continuously operate under illumination and darkness conditions for efficient E. coli inactivation. On account of the peroxidase mimics of the Au core and Fenton reactivity of the Cu2O shell, the Au@Cu2O nanocrystals exhibit intrinsic peroxidase-like property with the reaction kinetics in accordance with the typical Michaelis–Menten mechanism. On the other hand, time-resolved photoluminescence spectra suggest the prevalence of pronounced charge separation for Au@Cu2O nanocrystals, an important advantage that is favourable for photocatalysis. By combining the photocatalytic capability with the peroxidase mimics features, Au@Cu2O nanocrystals can perform practical photocatalytic decomposition of E. coli under visible light illumination but still show vital activity towards E. coli inactivation after light illumination was turned off. The current study delivers a new catalyst configuration by exploiting the multiple functionalities of nanosized Au and Cu2O for advanced environmental and energy conversion applications.

Postsynaptic development requires the Frizzled nuclear import (FNI) pathway entailing the internalization and subsequent cleavage of Frizzled-2. Kim et al. show that Drosophila ALS2 regulates postsynaptic development by directing Frizzled-2 trafficking to late endosomes, where the Frizzled-2 C terminus is cleaved, and also promotes neuronal survival independently of the FNI pathway., Mutations in the human ALS2 gene cause recessive juvenile-onset amyotrophic lateral sclerosis and related motor neuron diseases. Although the ALS2 protein has been identified as a guanine-nucleotide exchange factor for the small GTPase Rab5, its physiological roles remain largely unknown. Here, we demonstrate that the Drosophila homologue of ALS2 (dALS2) promotes postsynaptic development by activating the Frizzled nuclear import (FNI) pathway. dALS2 loss causes structural defects in the postsynaptic subsynaptic reticulum (SSR), recapitulating the phenotypes observed in FNI pathway mutants. Consistently, these developmental phenotypes are rescued by postsynaptic expression of the signaling-competent C-terminal fragment of Drosophila Frizzled-2 (dFz2). We further demonstrate that dALS2 directs early to late endosome trafficking and that the dFz2 C terminus is cleaved in late endosomes. Finally, dALS2 loss causes age-dependent progressive defects resembling ALS, including locomotor impairment and brain neurodegeneration, independently of the FNI pathway. These findings establish novel regulatory roles for dALS2 in endosomal trafficking, synaptic development, and neuronal survival.

Synaptic vesicle (SV) endocytosis is coupled to exocytosis to maintain SV pool size and thus neurotransmitter release. Intense stimulation induces activity-dependent bulk endocytosis (ADBE) to recapture large quantities of SV constituents in large endosomes from which SVs reform. How these consecutive processes are spatiotemporally coordinated remains unknown. Here, we show that Flower Ca2+channel-dependent phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) compartmentalization governs control of these processes inDrosophila. Strong stimuli trigger PI(4,5)P2microdomain formation at periactive zones. Upon exocytosis, Flower translocates from SVs to periactive zones, where it increases PI(4,5)P2levels via Ca2+influxes. Remarkably, PI(4,5)P2directly enhances Flower channel activity, thereby establishing a positive feedback loop for PI(4,5)P2microdomain compartmentalization. PI(4,5)P2microdomains drive ADBE and SV reformation from bulk endosomes. PI(4,5)P2further retrieves Flower to bulk endosomes, terminating endocytosis. We propose that the interplay between Flower and PI(4,5)P2is the crucial spatiotemporal cue that couples exocytosis to ADBE and subsequent SV reformation.

A series of FFK tripeptides capped with phenylacetic acid of various fluoro-substitutions at the N-terminus has been synthesized and examined for self-assembly under aqueous conditions. The material properties of the FFK tripeptides dramatically changed from precipitate to hydrogel phase upon increasing the number of fluorine atoms. Peptides linked with benzyl (B-FFK) or monofluoro-benzyl (MFB-FFK) groups rapidly form solid precipitates under physiological pH conditions. The trifluoro-decorated compound (TFB-FFK) self-assembled into a metastable hydrogel which slowly transformed into a solid precipitate upon standing. A stable hydrogel formation was noticed in the case of the pentafluorobenzyl-diphenylalanyllysine (PFB-FFK) compound. TEM analysis indicates that the PFB-FFK peptide assembled into twisted nanofibril structures, which are predominantly stabilized by strong quadrupole π-stacking interactions and electrostatic interactions of amino acid side chains. Furthermore, the combination of PFB-FFK and PFB-FFD peptides was also investigated for hydrogelation and the self-assembly of such systems resulted in the formation of untwisted 1D nanofibril structures. Supramolecular coassembled hydrogels of variable stiffness have also been achieved by modulating the concentration of the peptide components, which was evident from the rheological analysis. Such low molecular weight (LMW) peptide materials with tuneable mechanical properties might be a potential material for a wide range of applications in nanotechnology and biotechnology.

Supramolecular fluorescent materials with aggregation-induced emission (AIE) characteristics have promising applications as fluorescent probes for bio and chemosensors. In this study, a versatile low molecular weight tetraphenylethylene dipeptide hydrogelator (TPE-YY) with efficient AIE characteristics was developed, which was able to form hydrogels in a broad pH range from 3.7 to 10.2. The self-assembly of this hydrogel is completely pH-dependent, with significant structural transitions from high to low pH. At a relatively high pH value (10.2), a weak transparent hydrogel with an entangled network of nanofibers was obtained, while upon neutralization (pH 7.2) with dilute HCl, a stable semi-transparent gel with twisted nanobelts was formed. When the pH of the hydrogel was reduced to below 5.7, a turbid viscous gel and precipitation appeared with the thickening of the nanobelts. Surprisingly, the hydrogel resulting from the glucono-δ-lactone triggered gel showed only nanofibers independent of pH. The nature of the hydrogels and the nanostructures at different pH values were thoroughly examined and discussed via oscillatory rheology, electron microscopy and various spectroscopic techniques {1HNMR, 2D-NMR, Fourier transform infrared (FTIR) and Circular dichroism (CD)}. Interestingly, the self-assembled hydrogel exhibited excellent biocompatibility over 95% using hydrogel leachables on two different cell lines, 3A6 (human MSCs) and L929 (mouse fibroblast cells). Moreover, the self-assembled nanobelts formed at neutral pH showed excellent cell adhesion and proliferation of 3A6 cells, whereas the nanofibers showed poor cell adhesion and proliferation. Overall, we demonstrate the importance of chemical design for the formation of self-assembled nanobelts and supramolecular hydrogels at physiological pH with selective cell adhesion and proliferation, presenting a promising applications in tissue engineering and regenerative medicine.

Neuromuscular junctions (NMJs) govern rapid and efficient neuronal communication with muscle cells, which relies on the proper architecture of specialized postsynaptic compartments. However, the intrinsic mechanism in muscle cells contributing to elaborate NMJ development has been unclear. In this study, we reveal that the GTPase dynamin-2 (Dyn2), best-known for catalyzing synaptic vesicle endocytosis at the presynaptic membrane, is also involved in postsynaptic morphogenesis. We demonstrate that Dyn2 is enriched in the postsynaptic membrane of muscle cells and is involved in the maturation of neurotransmitter receptor clusters via its actin bundling ability. Dyn2 functions as a molecular girdle to regulate synaptic podosome turnover and promote morphogenesis of the postsynaptic apparatus. In Drosophila NMJs, Dyn2 is required to organize the postsynaptic actin cytoskeleton and to mediate its electrophysiological activities. Mechanistically, the actin binding, self-assembly, GTP hydrolysis ability, and Y597 phosphorylation of Dyn2 all regulate its actin bundling activity. Together, our study uncovers a role for Dyn2 in cytoskeleton remodeling and organization at the postsynaptic membrane of NMJs.

Understanding the structure-morphology relationships of self-assembled nanostructures is crucial for developing materials with the desired chemical and biological functions. Here, phosphate-based naphthalimide (NI) derivatives have been developed for the first time to study the enzyme-instructed self-assembly process. Self-assembly of simple amino acid derivative NI-Yp resulted in non-specific amorphous aggregates in the presence of alkaline phosphatase enzyme. On the other hand, NI-FYp dipeptide forms spherical nanoparticles under aqueous conditions which slowly transformed into partially unzipped nanotubular structures during the enzymatic catalytic process through multiple stages which subsequently resulted in hydrogelation. The self-assembly is driven by the formation of β-sheet type structures stabilized by offset aromatic stacking of NI core and hydrogen bonding interactions which is confirmed with PXRD, Congo-red staining and molecular mechanical calculations. We propose a mechanism for the self-assembly process based on TEM and spectroscopic data. The nanotubular structures of NI-FYp precursor exhibited higher cytotoxicity to human breast cancer cells and human cervical cancer cells when compared to the nanofiber structures of the similar Fmoc-derivative. Overall this study provides a new understanding of the supramolecular self-assembly of small-molecular-weight hydrogelators.

We report a novel fluorescent bioprobe, tetraphenylethylene-Phe-Asp-Gly-Glu-Ala (TPE-FDGEA), and its self-assembly behavior, photophysical properties, and biocompatibility. The hydrogelator TPE-FDGEA exhibited aggregation-induced emission characteristics, which facilitated imaging of PC-3 human prostate cancer cells, thereby demonstrating the utility of such fluorescent probes for specific labeling of target cells in vitro.

Neuromuscular junctions (NMJs) govern efficient neuronal communication with muscle cells, relying on proper architecture of specialized postsynaptic compartments. However, the intrinsic mechanism in muscle cells contributing to NMJ development remains unclear. In this study, we reveal that dynamin-2 (Dyn2) is involved in postsynaptic development of NMJs. Mutations of Dyn2 have been linked to human muscular disorder and centronuclear myopathy (CNM), as well as featured with muscle atrophy and defective NMJs, yet the function of Dyn2 at the postsynaptic membrane is largely unknown. We demonstrate that Dyn2 is enriched at the postsynaptic membrane and regulates NMJ development via actin remodeling. Dyn2 functions as an actin-bundling GTPase to regulate podosome turnover and cytoskeletal organization of the postsynaptic apparatus, and CNM-Dyn2 mutations display abnormal actin remodeling and electrophysiological activity of fly NMJs. Altogether, Dyn2 primarily regulates actin cytoskeleton remodeling and NMJ morphogenesis at the postsynaptic membrane, which is distinct from its endocytosis regulatory role at the presynaptic membrane.

Herein, we demonstrate an example of glucosamine-based supramolecular hydrogels that can be used for human mesenchymal cell therapy. We designed and synthesized a series of amino acid derivatives based on a strategy of capping d-glucosamine moiety at the C-terminus and fluorinated benzyl group at the N-terminus. From a systematic study on chemical structures, we discovered that the glucosamine-based supramolecular hydrogel [pentafluorobenzyl (PFB)-F-Glu] self-assembled with one-dimensional nanotubular structures at physiological pH. The self-assembly of a newly discovered PFB-F-Glu motif is attributed to the synergistic effect of π-π stacking and extensive intermolecular hydrogen bonding network in aqueous medium. Notably, PFB-F-Glu nanotubes are proven to be nontoxic to human mesenchymal stem cells (hMSCs) and have been shown to enhance hMSC proliferation while maintaining their pluripotency. Retaining of pluripotency capabilities provides potentially unlimited source of undifferentiated cells for the treatment of future cell therapies. Furthermore, hMSCs cultured on PFB-F-Glu are able to secrete paracrine factors that downregulate profibrotic gene expression in lipopolysaccharide-treated human skin fibroblasts, which demonstrates that PFB-F-Glu nanotubes have the potential to be used for wound healing applications. Overall, this article addresses the importance of chemical design to generate supramolecular biomaterials for stem cell therapy.

Central and peripheral nerve injuries can lead to permanent paralysis and organ dysfunction. In recent years, many cell and exosome implantation techniques have been developed in an attempt to restore function after nerve injury with promising but generally unsatisfactory clinical results. Clinical outcome may be enhanced by bio-scaffolds specifically fabricated to provide the appropriate three-dimensional (3D) conduit, growth-permissive substrate, and trophic factor support required for cell survival and regeneration. In rodents, these scaffolds have been shown to promote axonal regrowth and restore limb motor function following experimental spinal cord or sciatic nerve injury. Combining the appropriate cell/exosome and scaffold type may thus achieve tissue repair and regeneration with safety and efficacy sufficient for routine clinical application. In this review, we describe the efficacies of bio-scaffolds composed of various natural polysaccharides (alginate, chitin, chitosan, and hyaluronic acid), protein polymers (gelatin, collagen, silk fibroin, fibrin, and keratin), and self-assembling peptides for repair of nerve injury. In addition, we review the capacities of these constructs for supporting in vitro cell-adhesion, mechano-transduction, proliferation, and differentiation as well as the in vivo properties critical for a successful clinical outcome, including controlled degradation and re-absorption. Finally, we describe recent advances in 3D bio-printing for nerve regeneration.

Herein, the influence of an amino acid side chain on the structural and functional properties of hydrogels has been described. In this study, four new hydrogelators based on the conjugates of dipeptides and naphthalimide (NI) have been designed, synthesized, and examined. Homopeptide 1 (NI-FF) of the phenylalanine residue forms a weak hydrogel or a viscous solution of worm-like micelles under basic conditions. On the other hand, dipeptide conjugates of 2 (NI-FY), 3 (NI-YF), and 4 (NI-YY), containing additional hydroxyl groups as tyrosine residues, can self-assemble into supramolecular hydrogels under physiological pH conditions. UV-vis, IR, and rheological studies clearly indicate the formation and stability of these dipeptide hydrogels. The TEM results revealed that the hydrogels (1–4) self-assembled into a nanofibrous morphology. Furthermore, the cell culture results show that NI-YF has better cell compatibility as compared to NI-FY and NI-YY and thus shows potential to be used as a hydrogel biomaterial. Overall, this study highlights the importance of the structure–hydrogelation relationship and provides new insights into the design of self-assembled peptide amphiphiles.

This report describes the two component self-assembly of π-capped amino acid hydrogelators (serine (S), aspartic acid (D), glutamic acid (E) or lysine (K)) prepared from pyrene (Py) based donor and naphthalenediimide (NDI) based acceptor molecules. The co-assembly can be triggered to form hydrogels by varying the pH conditions and the major driving forces behind the hydrogelation were found to be the formation of a strong charge-transfer (CT) complex and hydrogen bonding interactions at suitable pH conditions. The NDI-Py blends with matched donor/acceptor amino acid pairs undergo self-assembly under acidic pH conditions, whereas the blend (NDI-S + Py-K) with a mismatched amino acid pair forms a stable hydrogel under physiological pH conditions. UV-Vis, FTIR and rheological studies clearly indicate the formation and the stability of these CT-induced hydrogels. These hydrogels are of nanofibrous morphology with an average diameter of about 6-9 nm as evidenced by TEM analysis. In addition, this novel NDI-Py mixed component system exhibited good biocompatibility towards PC3 cells. Overall, since hydrogels based on CT-mediated two-component assemblies are very rare, our newly discovered NDI-Py hydrogels provide chemical insights into the design of a CT-induced hydrogelator and might facilitate various applications in biomedical engineering.

Herein, we report the synthesis of simple TPE/single amino acid conjugates, TPE-Ser and TPE-Asp with side-chains featuring functional groups that may provide an additional hydrogen bonding network for hydrogelation in aqueous medium. TPE-Ser, which has the lowest molecular weight, containing hydroxyl groups undergoes self-assembly into supramolecular hydrogels under physiological pH conditions. TPE-Asp with a carboxylic group side chain undergoes the self-assembly and hydrogelation processes under slightly acidic conditions (pH = 6.0). UV-vis, IR, PL and rheological studies clearly indicate the formation, stability and fluorescence properties of TPE-amino acid hydrogels. TEM micrographs of the hydrogels indicate that the compounds are self-assembled into a nanosheet morphology with random size and shape. Further, in vitro analysis of TPE-Ser and TPE-Asp with 3A6 cells shows that the compounds exhibit unique fluorescence signals in microcellular environments thus making them suitable candidates for bioimaging applications. Overall, these findings highlight the importance of the structure-hydrogelation relationship and provide new insights into the design of single amino-acid-based supramolecular hydrogels.

A composite molecule (CM) model is used to investigate the nature of intermolecular interactions in the excited states of π-conjugated oligomers of poly-(p-phenylene) (PPP). The dependence of the charge-transfer (CT) interactions in low-lying excited states as a function of intermolecular distance, conjugation length, and the translation shifts is examined. We demonstrate how the amplitude of CT mixing in two low-lying excited states of PPP dimer is sensitive to various aspects of molecular packing. The largest CT mixing in the two excited states is consistently obtained for cofacial packing. However, from a detailed examination of molecular orbital shapes and interactions, it is seen that specific arrangements promote the CT mixing in two low-lying transitions. With cofacial arrangements, it shows a larger percentage of CT in the first excited states than the corresponding second excited states for phenyl rings on the top of Csp2─Csp2 single bonds. This work illustrates the importance of molecular packing–CT mixing relationship of functional π-conjugated materials.

The neuromuscular junction (NMJ) governs rapid and efficient neuronal communication with muscle cells, which relies on the proper activity of postsynaptic compartment specialized with unique membrane and actin-dependent cytoskeleton organization. However, the intrinsic mechanism in muscle cells that contributes to the development and maintenance of the elaborate NMJ morphology is unclear. In this study, we discover that the large GTPase, dynamin, best-known for catalyzing synaptic vesicle endocytosis at the presynaptic membrane, is also involved in postsynaptic morphogenesis. By using cultured mouse myotube, Drosophila, and in vitro reconstitution assay, we demonstrate that dynamin-2 (Dyn2) is enriched in the postsynaptic membrane of muscle cells and is involved in the maturation of neurotransmitter receptor clusters and the functional integrity of NMJ. During the early stage of NMJ development, Dyn2 functions as a molecular girdle to regulate synaptic podosome turnover and promote the maturation of postsynaptic apparatus. After the maturation, Dyn2 remains enriched at NMJ to maintain proper actin cytoskeleton organization and its electrophysiological function. The self-assembly, GTP hydrolysis ability and Y597 phosphorylation of Dyn2 determine its localization at podosome and the actin bundling activity. Together, our results uncover a new function of Dyn2 on cytoskeleton remodeling and organization at the postsynaptic membrane of NMJ.

The neuroimaging techniques such as dopaminergic imaging using Single Photon Emission Computed Tomography (SPECT) with 99mTc-TRODAT-1 have been employed to detect the stages of Parkinson’s disease (PD). In this retrospective study, a total of 202 99mTc-TRODAT-1 SPECT imaging were collected. All of the PD patient cases were separated into mild (HYS Stage 1 to Stage 3) and severe (HYS Stage 4 and Stage 5) PD, according to the Hoehn and Yahr Scale (HYS) standard. A three-dimensional method was used to estimate six features of activity distribution and striatal activity volume in the images. These features were skewness, kurtosis, Cyhelsky’s skewness coefficient, Pearson’s median skewness, dopamine transporter activity volume, and dopamine transporter activity maximum. Finally, the data were modeled using logistic regression (LR) and support vector machine (SVM) for PD classification. The results showed that SVM classifier method produced a higher accuracy than LR. The sensitivity, specificity, PPV, NPV, accuracy, and AUC with SVM method were 0.82, 1.00, 0.84, 0.67, 0.83, and 0.85, respectively. Additionally, the Kappa value was shown to reach 0.68. This claimed that the SVM-based model could provide further reference for PD stage classification in medical diagnosis. In the future, more healthy cases will be expected to clarify the false positive rate in this classification model.

Herein, we report the synthesis and optimization of an aqueous phase two-component co-assembled nanofibrous hydrogel based on charge-transfer (CT) between pyrenebutyric acid and naphthalene diimide-capped groups. This donor–acceptor CT interaction is a powerful driving force that can induce self-assembly in the aqueous phase even if the molecule contains only a single amino acid. The intermolecular CT interactions for mixed components can also be visualized in the quantum-chemical approach. This two-component supramolecular co-assembly provides a new path for the design of self-assembled nanomaterials.

Gelatin is an important hydrocolloid which has widespread applications in the pharmaceutical industry and biomedical science. However, despite its significance, clinical applications of gelatin are largely limited because of its gel-to-solution transition around human body temperature. In this work, we developed a series of F127–gelatin composite hydrogels with reverse thermo-responsive properties. The stiffness of F127–gelatin hydrogels can be adjusted by varying the types and contents of gelatin (type A, GA and type B, GB). The results of rheological data showed that F127–GA gels have higher gel strengths than those of F127–GB, which might be due to different isoelectric points between GA and GB. In addition, F127–gelatin gels showed significant cell viability and biocompatibility for human mesenchymal stem cells, indicating that these discovered hydrogels can serve as potential biomaterials and implantable scaffolds for applications in tissue engineering and regenerative medicine.

• Anthropophilic and zoophilic strain of T. interdigitale are morphologically identical.

Realizing facial expression is likely to be one of the earliest facilitators of social engagement, and it is a core deficit for individuals with autism spectrum disorder (ASD) to build social relationship. Mobile learning creates the possibility of a learning environment and visual stimuli that can adapt its informal learning contexts to improve recognizing emotions for people with ASD. This study adopted features of mobile learning to help the realization of facial expression for the ASD. The proposed 3D Complex Facial Expression Recognition (3CFER) system was developed to help the deficit in facial expressions for this population. This study therefore, explored how children with ASD performed realizing facial expression using the 3CFER system; and how the phenomena of using the learning system for people with ASD performs. Participants (n = 24, 16 males and 8 females, m = 11.3 years old) were randomly assigned to either a control or an experimental group, and were involved with the pre-and post-test sessions. The control was not engaged in the system-treatment; and the experimental undertook the system-operation. The result showed that the experimental had great improvement in realizing facial expression compared with control, and surprise and shyness were mostly easy to be identified for them. The performance of using mobile learning system was promising well. However, the informal experience of recognizing facial expression in different social contexts was meaningful learning for this population.

A new bottom-up strategy based on aromatic peptide amphiphile is developed for a high-contrast visualization of 3D live cell-material imaging-something that has been difficult to achieve previously because of the problems associated with the diffraction of light by the nanosized peptide materials and the aggregation-caused quenching of aggregated π-conjugated fluorophores in the nanostructures. This study reports an example of a novel supramolecular hydrogelator, naphthaleneimide-phenylalanine (NI-Phe), which forms a self-supporting hydrogel displaying a unique microfibrous network and promising aggregation-induced emission characteristics at pH 7.4. The storage modulus of the NI-Phe gel supports the mass of a cell for 3D cell culturing. This work illustrates a new dopant-free supramolecular approach, complementary to well-established doping procedures that should facilitate the development of live cell imaging in 3D scaffolding materials.

Anti-VEGF therapies benefit several cancer types, but drug resistance that limits therapeutic response can emerge. We generated cell lines from anti-VEGF–resistant tumor xenografts to investigate the mechanisms by which resistance develops. Of all tumor cells tested, only A431 (A431-V) epidermoid carcinoma cells developed partial resistance to the VEGF inhibitor aflibercept. Compared with the parental tumors, A431-V tumors secreted greater amounts of IL6 and exhibited higher levels of phospho-STAT3. Notably, combined blockade of IL6 receptor (IL6R) and VEGF resulted in enhanced activity against A431-V tumors. Similarly, inhibition of IL6R enhanced the antitumor effects of aflibercept in DU145 prostate tumor cells that displays high endogenous IL6R activity. In addition, post hoc stratification of data obtained from a clinical trial investigating aflibercept efficacy in ovarian cancer showed poorer survival in patients with high levels of circulating IL6. These results suggest that the activation of the IL6/STAT3 pathway in tumor cells may provide a survival advantage during anti-VEGF treatment, suggesting its utility as a source of response biomarkers and as a therapeutic target to heighten efficacious results. Cancer Res; 76(8); 2327–39. ©2016 AACR.

Glycopeptide-based hydrogelators with well-defined molecular structures and varied contents of sugar moieties were prepared via in vitro peptide glycosylation reactions. With systematic glucose modification, these glycopeptide hydrogelators exhibited diverse self-assembling behaviors in water and formed supramolecular hydrogels with enhanced thermostability and biostability, in comparison with their peptide analogue. Moreover, because of high water content and similar structural morphology and composition to extracellular matrixes (ECM) in tissues, these self-assembled hydrogels also exhibited great potential to act as new biomimetic scaffolds for mammalian cell growth. Therefore, peptide glycosylation proved to be an effective means for peptide modification and generation of novel supramolecular hydrogelators/hydrogels with improved biophysical properties (e.g., high biostability, increased thermostability, and cell adhesion) which could promise potential applications in regenerative medicine.

Here we report the generation of a novel gelator from a glycosylated amino acid derivative, which contained three structural units, an aromatic residue, a carbohydrate moiety and a tert-butyl group in a single molecule. These structural units can promote the supramolecular self-assembly of this gelator in both aprotic and protic solvents via coordinated π-π stacking, multiple hydrogen binding and van der Waals interactions. More importantly, due to their non-equilibrium natures, the organogels formed in DCM, chloroform and ethanol can undergo gel to crystal transition in storage, driven by unbalanced gelator-gelator and solvent-gelator interactions. In this process, the gelators were firstly trapped in a kinetically favorable gel state, and then transferred into a more thermodynamically stable crystal state upon ageing, with the generation of microcrystals in different morphologies.

Herein, we report a tetraphenylethylene-diglycine (TPE-GG) hydrogelator from a systematic study of TPE-capped dipeptides with various amphiphilic properties. From a chemical design, we found that the hydrogelation of TPE-GG molecules can be utilized to generate supramolecular nanostructures with a large TPE-based nanobelt width (∼300 nm) and lateral dimension ratio (>30 fold). In addition, TPE-GG has the lowest molecular weight and minimum number of atoms compared to any TPE-capped peptide hydrogelator reported to date. This minimal self-assembled hydrogelator can fundamentally achieve the gel features compared with other TPE-capped peptides. A combined experimental and computational study indicates the π-π interactions, electrostatic interactions and hydrogen-bonding interactions are the major driving forces behind the formation of self-assembled nanobelts. This study demonstrates the importance of structure-property relationships and provides new insights into the design of supramolecular nanomaterials.

Arteriovenous graft (AVG) failure continues to be a life-threatening problem in haemodialysis. Graft failure can occur if the implanted graft is not well-matched to the vasculature of the patient. Likewise, stenosis often develops at the vein-graft anastomosis, contributing to thrombosis and early graft failure. To address this clinical need, a novel ink formulation comprised of ACMO/TMPTA/TMETA for 3D printing a AVG was developed (ACMO-AVG), in which the printed AVG was biocompatible and did not induce cytotoxicity. The ease of customizing the ACMO-AVG according to different requirements was demonstrated. Furthermore, the AVG displayed similar mechanical properties to the commercially available arteriovenous ePTFE graft (ePTFE-AVG). Unlike ePTFE-AVG, the ACMO-AVG displayed excellent anti-fouling characteristics because no plasma protein adsorption and platelet adhesion were detected on the luminal surfaces after 2 h of incubation. Similarly, exposure to human endothelial cells and human vascular smooth muscle cells did not result in any cell detection on the surfaces of the ACMO-AVG. Thus, the present study demonstrates a newly developed 3D printing ink formulation that can be successfully 3D printed into a clinically applicable vascular access used for haemodialysis.

To screen the possibility of forming self-assembled hydrogels under physiological pH, various molar ratios of the hydrogelators based on pentafluorobenzyl-phenylalanine (PFB-F) and pentafluorobenzyl-diphenylalanine (PFB-FF) were studied. The equimolar ratio of PFB-F and PFB-FF formed coassembled nanofibers and a self-supporting hydrogel at the physiological pH of 7.4. The spectroscopic characterization of the blend gel indicates that π–π interactions and hydrogen-bonding interactions are the major driving forces behind the coassembly. In addition, we also prove that the blend hydrogel is biocompatible, thus making it a scaffolding material for biomedical applications. In this work, the utility of two distinct hydrogelators to promote coassembly under physiological condition expands the repertoire of noncovalent interactions that can be used in the development of sophisticated noncovalent biomaterials.

The influence of aliphatic chain lengths on supramolecular hydrogelation of naphthalene diimide-capped dipeptides is described. The dependence of the gelation pH as a function of chain lengths reveals an inverse linear relationship and the gelation pH values cover a broad range from pH 2 to pH 9. In addition, the presence of a n-octyl tail in the hydrogelator could enhance the ability of self-assembly in dilute solution.

The combination of a naphthalene diimide (NDI) group and a single amino-acid of serine (Ser) or lysine (Lys) can be used to promote the formation of a supramolecular hydrogel, which indicates the aromatic amino acid is not necessary to be used in the structural design of NDI-capped small molecule hydrogelators. An equimolar ratio of NDI-Ser and NDI-Lys can form a stable hydrogel under neutral conditions and its gel-to-sol transition temperature is higher than 37 °C. This work, as the first example of NDI-containing hydrogelators without aromatic rings in the side chains of amino acids, illustrates a new approach to design NDI-capped supramolecular hydrogels.

We report a new aromatic-capped peptide amphiphile which is able to form a supramolecular hydrogel under neutral pH. This hydrogel can also be obtained by enzymatic transformation from the hydrogelator precursor. The newly discovered hydrogel has excellent biocompatibility for four different cell lines, thus making it a potentially useful scaffolding material for biomedical applications.

With the replacement of only one hydrogen atom by fluorine, 4-fluorobenzyl-diphenylalanine was able to form a transparent hydrogel, while benzyl-diphenylalanine did not under similar conditions, indicating the remarkable effect of fluorine on supramolecular hydrogelation.

This article describes the self-assembly of π-conjugated building blocks composed of single amino acid and pyrene (Py) moieties. In aqueous conditions, the Py-capped amino acids undergo self-assembly through various non-covalent interactions such as hydrogen-bonding, π–π stacking as well as electrostatic interactions to form supramolecular nanostructures in acidic and basic conditions. Interestingly, we found that the blend of different Py-gelators with oppositely charged amino acids (Py–Glu and Py–Lys) displays unique nano-structural morphologies and gelation properties of the resulting hydrogels at physiological pH when compared with single Py conjugates, which was attributed to additional electrostatic interactions. Overall, this report illustrates the importance of two-component supramolecular co-assembled hydrogels and their structure–morphology relationship, improved mechanical properties, and biocompatibility and thus provides a new insight into the design of self-assembled nanomaterials.

In this study, we examined the self-assembly of four dipeptides conjugated with the electroactive dye naphthalenediimide (NDI). The presence of the NDI group at the N-terminus of Phe-Phe and Phe-Gly promoted the formation of one-dimensional (1-D) nanostructures and three-dimensional (3-D) colored hydrogels under both acidic and physiological conditions. The 1-D nanostructures of these gels were stabilized through intermolecular π-π interactions of the conjugated systems and extended hydrogen bonding of the dipeptide units.

A new system for the incorporation of a phenyl/perfluorophenyl pair in the structure of a peptide hydrogelator was developed. The strategy is based on the idea that the integration of an end-capped perfluorophenyl group and a phenylalanine with a phenyl moiety in the side chain forms an intramolecular phenyl/perfluorophenyl pair, which can be used to promote the formation of the supramolecular nanofibers and hydrogels. This work illustrates the importance of structure-hydrogelation relationship and provides new insights into the design of self-assembly nanobiomaterials.