In situ hydrogelation of forky peptides in prostate tissue for drug delivery.

Herein, we have designed and synthesized a novel forky peptide D3F3 that transforms into a hydrogel through crosslinking induced by ZIs stimuli. We have employed D3F3 as a suitable drug carrier that is conjugated with DOX. Since the concentration of zinc ions necessary for triggering gelation falls into the physiological range present in prostate tissue, while other cationic ions fail to trigger at physiological concentrations, the peptide-based drug delivery system (DDS) is injectable and would achieve prostate tissue-specific self-assembly in situ. The D3F3 hydrogels exhibited an optimal gelation time, satisfactory mechanical strength (can be enhanced after incorporation of DOX) as well as excellent thixotropic properties. The DDS reserved some DOX in the prostate 24 h after the injection, making local sustained release possible. In addition, the peptide materials demonstrated no cytotoxicity against normal fibroblast cells and no damage was observed to the prostate tissue of rats. The drug release followed a non-Fickian diffusion model, with no burst release observed. Importantly, the DOX-hydrogel system exhibited good anti-cancer efficacy when incubated with prostate cancer cells DU-145. Therefore, this study lays the groundwork for the future design of tissue-specific DDSs that are triggered by cationic ions (e.g. zinc ions), and the platform could be further developed to incorporate other potent drugs utilized in the field of prostate cancer therapy, thereby increasing their potency and reducing their side effects.

Supramolecular self-assembly of fluorescent peptide amphiphiles for accurate and reversible pH measurement.

We report the synthesis and self-assembly of fluorescent peptide amphiphiles (NBD-PA) composed of a fluorescent NBD probe and a peptide derivative VVAADD with a C12-alkyl-chain as the linker (NBD-C12-VVAADD). The self-assembly of NBD-PA formed beta-sheet structures at neutral pH in aqueous solution, contributed to an ∼10-fold increase in the fluorescence and quantum yield of NBD molecules, and conferred a supramolecular hydrogel with excellent viscoelastic properties, while gel-to-sol transition of NBD-PA occurred rapidly when the pH value was adjusted to strongly alkaline (e.g. pH 11). Through the pH-responsive self-assembly behavior, we further explored the relationship between fluorescence of NBD-PA and pH values. Interestingly, the fluorescence of the NBD-PA system exhibited an excellent sigmoidal function relationship (R2 = 0.9999) with the alkaline pH values, which enabled accurate pH measurement regardless of salt types and ionic strength of solvents. Furthermore, the fluorescence of NBD-PA was fully reversible upon cycles of pH shifts, with the chemical structure of NBD-PA well-maintained throughout the process. These features of NBD-PA would facilitate the design of in situ pH detection systems as well as pH-responsive actuators for various applications in future.

Doxorubicin-reinforced supramolecular hydrogels of RGD-derived peptide conjugates for pH-responsive drug delivery.

Drug incorporation in hydrogels often brings undesirable effects on the stability or mechanical properties of the system. To address this problem, we report the design and synthesis of a RGD-derived peptide conjugate (1-RGDH) for its co-assembly with a commonly used chemotherapeutic drug, doxorubicin (DOX), that formed electrostatic interactions with the 1-RGDH peptide and reinforced the supramolecular network of nanofibers within the matrix of the hydrogel. The hybrid hydrogel demonstrated excellent viscoelastic and shear-thinning properties that greatly facilitated the development of injectable drug delivery systems. Furthermore, it demonstrated a unique pH responsive release of DOX under weakly acidic conditions, paving ways for the controlled release of drug cargos in a typical tumor microenvironment with mild acidity. Finally, the DOX-incorporated hydrogel exhibited a superior anti-tumor efficacy in non-small-cell lung cancer cells A549 compared to the aqueous solution of free DOX, with an integrin receptor-mediated endocytosis pathway revealed for the cellular uptake of DOX-incorporated nanofibers.

Size-Dependent Grain-Boundary Structure with Improved Conductive and Mechanical Stabilities in Sub-10-nm Gold Crystals.

Low-angle grain boundaries generally exist in the form of dislocation arrays, while high-angle grain boundaries (misorientation angle >15°) exist in the form of structural units in bulk metals. Here, through in situ atomic resolution aberration corrected electron microscopy observations, we report size-dependent grain-boundary structures improving both stabilities of electrical conductivity and mechanical properties in sub-10-nm-sized gold crystals. With the diameter of a nanocrystal decreasing below 10 nm, the high-angle grain boundary in the crystal exists as an array of dislocations. This size effect may be of importance to a new generation of interconnects applications.

Acupuncture promotes white adipose tissue browning by inducing UCP1 expression on DIO mice.

BACKGROUND: To study the influence of acupuncture and its possible mechanism on white adipose tissue of high fat diet-induced obese. METHODS: Four-week-old C57BL/6 J mice were randomly divided into a normal diet group and a high-fat diet (HFD) group. After 8 weeks, the HFD mice were randomly divided into Electro-acupuncture (EA) group and control group. Mice in the EA group were electro-acupunctured, under physical restraint, on Zusanli (ST36) and Neiting (ST44) acupoints, while the mice in the control group were under physical restraint only. Body weight and food intake were monitored, and serum leptin, cholesterol and triglyceride levels were measured by using biochemistrical methods. The effect of EA on white adipose tissues (WAT) was assessed by qPCR, immunoblotting, immunohistochemistry (IHC), immunoprecipitation and cold endurance experiment. RESULTS: The WAT/body weight ratio decreased (P < 0.05) in the EA group, albeit no significant difference on food consumption between EA and control groups. The difference in the darkness of Epi-WAT between EA and control groups could be distinguished visually. HE staining indicated that the EA mice had an increased number of UCP1-immunoreactive paucilocular adipocytes in their WAT. The expressions of brown adipose tissue (BAT) markers, including UCP1, COX4il and Nrtf1 were increased in the WAT of EA mice, acetylation of Pparγ was decreased by electro-acupuncture. CONCLUSION: EA can remodel WAT to BAT through inducing UCP1 expression, and this may be one of the mechanisms by which acupuncture affects weight loss.

Electro-acupuncture at Neiguan pretreatment alters genome-wide gene expressions and protects rat myocardium against ischemia-reperfusion.

This study investigated genome-wide gene expressions and the cardioprotective effects of electro-acupuncture pretreatment at the PC6 Neiguan acupoint on myocardial ischemia reperfusion (I/R) injury. Male SD rats were randomly divided into four groups: sham operation (SO), I/R, electro-acupuncture at the PC6 Neiguan acupoint pretreatment (EA) and electro-acupuncture at non-acupoint pretreatment (NA). Compared with the I/R group, the survival rate of the EA group was significantly increased, the arrhythmia score, infarction area, serum concentrations of CK, LDH and CK-Mb and plasma level of cTnT were significantly decreased. RNA-seq results showed that 725 genes were up-regulated and 861 genes were down-regulated under I/R conditions compared to the SO group; both EA and NA reversed some of these gene expression levels (592 in EA and 238 in NA group). KEGG pathway analysis indicated that these genes were involved in multiple pathways, including ECM, MAPK signaling, apoptosis, cytokine and leukocyte pathways. In addition, some pathways were uniquely regulated by EA, but not NA pretreatment, such as oxidative stress, cardiac muscle contraction, gap junction, vascular smooth muscle contraction, hypertrophic, NOD-like receptor, and P53 and B-cell receptor pathways. This study was first to reveal the gene expression signatures of acute myocardial I/R injury and electro-acupuncture pretreatment in rats.

High Reversible Strain in Nanotwinned Metals.

Development of bulk metals exhibiting large reversible strain is of great interest, owing to their potential applications in flexible electronic devices. Bulk metals with nanometer-scale twins have demonstrated high strength, good ductility, and promising electrical conductivity. Here, ultrahigh reversible strain as high as ∼7.8% was observed in bent twin lamellae with 1-2 nm thickness in nanotwinned metals, where the maximum reversible strain increases with the reduction in twin lamella thickness. This high reversible strain is attributed to the suppression of dislocation nucleation, including both hard mode dislocations in the bent twin lamellae, while soft mode dislocations along twin boundaries have insignificant contribution. In situ transmission electron microscopy experiments show that higher recoverability was achieved in twinned Au nanorods compared with twin-free ones with similar aspect ratios and diameters during bending deformation, which demonstrates that the introduction of thin twin lamellae also significantly improves the shape recoverability of Au nanorods. This result introduces a novel pathway for developing bulk metals with the capability for large reversible strain.

In situ observation of twin-assisted grain growth in nanometer-scaled metal.

For nanometer-scaled materials, grain boundary behaviors, such as grain coalescence and grain boundary migration, contribute significantly to the plasticity of materials. While mechanically driven grain growth has been observed in nanometer-scaled metals, its underlying mechanisms are still poorly understood especially for those correlated with twins. By using in situ aberration-corrected transmission electron microscopy and precession electron diffraction, we have directly revealed nanotwin assisted grain growth for low angle grain boundaries. The grains with low angle grain boundaries coalesce by firstly forming twin pairs, whose coherent twin boundaries then serve as fast lanes for dislocations, and thus dissolving the low angle grain boundaries. During this process, the constitute dislocations of the low angle grain boundaries decompose into Shockley partial dislocations, which subsequently move along the coherent twin boundaries. After all the constitute dislocations dissociate and move out, two grains will coalesce and twin pairs merge into complete twin lamellae. For high angle grain boundaries, portions of grain boundaries intersected with nanotwins show higher mobility for migration under external stress. This investigation provides insight to twin related grain boundary behaviors in nanometer-scaled metals.

Instant Self-Assembly Peptide Hydrogel Encapsulation with Fibrous Alginate by Microfluidics for Infected Wound Healing.

Infected wounds caused by persistent inflammation exhibit poor vascularization and cellular infiltration. In order to rapidly control the inflammatory effect and accelerate wound healing, it is necessary to develop a novel drug vehicle addressing the need for infected wounds. Herein, we developed a novel dual-drug delivery system with micrometer-scale alginate fibers encapsulated in instant self-assembly peptide hydrogel. Short peptides with the sequence of Nap-Gly-Phe-Phe-Lys-His (Nap-GFFKH) could self-assemble outside the microfluidic-based alginate microfibers in weak acidic solution (pH ≈ 6.0) within 5 s. The gelation condition is close to the pH environment of the human skin. We further constructed recombinant bovine basic fibroblast growth factor (FGF-2) in fibrous alginate, which was encapsulated in antibiotic-loaded peptide hydrogel. The dual-drug delivery system exhibited good mechanical property and sustained release profiles, where antibiotic could be rapidly released from the peptide hydrogel, while the growth factor could be gradually released within 7 days. Both in vitro antibacterial experiments and in vivo animal experiments confirmed that such a dual-drug delivery system has good antibacterial activity and enhances wound healing property. We suggested that the dual-drug delivery system could be potentially applied for controlled drug release in infected wound healing, drug combination for melanoma therapy, and tissue engineering.

Co-assembled supramolecular hydrogels of doxorubicin and indomethacin-derived peptide conjugates for synergistic inhibition of cancer cell growth.

Conjugation of indomethacin with a self-assembling peptide moiety affords co-assembled supramolecular nanostructures of doxorubicin and peptide derivatives for tunable release of two drugs and synergistic effects against cancer cells, which illustrates a simple and effective approach to utilize co-assembled nanostructures for co-delivery of self-complementary drug pairs.

In situ hydrogelation of bicalutamide-peptide conjugates at prostate tissue for smart drug release based on pH and enzymatic activity.

Tissue-specific self-assemblies of supramolecular hydrogels have attracted great interest in material design and biomedical applications, for in situ-formed hydrogels serve as an excellent local depot with tunable release of drug therapeutics. Here we report the design and syntheses of a novel class of histidine-containing hexapeptide derivatives (Nap-1 and ID-1) for in situ hydrogelation at the zinc ion-rich prostate tissue. Thanks to the efficient co-ordination between zinc and histidine, both Nap-1 and ID-1 displayed excellent self-assembly capability with a high sensitivity to zinc ions at ∼0.1 equivalency. To foster a prostate-specific drug delivery system (DDS), ID-1 was chosen for further conjugation with bicalutamide (BLT), a clinically used drug for prostate cancer. The as-synthesized ID-1-BLT retained the self-assembly capability with zinc ions, and conferred supramoelcular hydrogels at the prostate site. Interestingly, ID-1-BLT hydrogels demonstrated tunable drug release profiles in a typical tumor microenvironment, with acidic pH and esterase activity regulating the drug release in a dose dependent manner. Consequently, the hydrogel-based DDS demonstrated enhanced potency and selective cytotoxicity against prostate cancer cell DU145 over normal fibroblast cell NIH3T3, plausibly due to differential cellular uptake of drugs as well as the elevated esterase activities in cancer cells. Finally, the biocompatible hydrogel system demonstrated sustained delivery of drugs at the prostate gland of rats, with a superior in situ drug distribution profile compared to that of aqueous solution of BLT alone.

The conjugates of forky peptides and nonsteroidal anti-inflammatory drugs (NSAID) self-assemble into supramolecular hydrogels for prostate cancer-specific drug delivery.

Herein, we report supramolecular hydrogelators made of forky peptides and nonsteroidal anti-inflammatory drugs (NSAID). Two zinc ions (ZIs)-responsive short peptide dendrons (E3FID and E3FNP) modified by NSAID (indometacinand naproxen) were designed and synthesized successfully. These novel small molecule hydrogelators can self-assemble in water to form stable supramolecular nanofibers/hydrogels. The formation of these supramolecular hydrogels can be triggered by zinc ions, which are highly concentrated in prostate tissue. The anticancer drug docetaxel (DTX) was employed as chemotherapeutic and loaded into the hydrogels to construct a novel drug delivery system for prostate cancer therapy. This approach is anticipated realizing the sustained release of antitumour drugs into the prostate and cancer associated pain relief, simultaneously. The E3FID hydrogel and E3FNP hydrogel have excellent biocompatibility and viscoelastic properties as a promising drug delivery materials. The result of drugs release in vitro indicated that DTX was released slowly following a non-Fickian diffusion mechanism. In addition, the results of the in vitro cytotoxicity assay demonstrated that these DTX-loaded hydrogels exhibited dose-dependent cytotoxicity to both DU-145 cells and PC-3 cells, in particular, the drug-loaded hydrogel of E3FID had better anticancer efficacy. As a drug delivery strategy, the system realizes better anticancer efficacy, excellent sustained-release and relief of cancer pain, simultaneously, the most important being that the DDS facilitates local delivery of drug to the prostate.

Zinc-ion-mediated self-assembly of forky peptides for prostate cancer-specific drug delivery.

A novel forky peptide was designed and synthesized. The peptide self-assembled into supramolecular hydrogels triggered by zinc ions (ZIs). The hydrogels were designed for a drug delivery system (DDS), loaded with docetaxel and applied for the therapy of prostate cancer. In this research, we have discussed the response mechanism and evaluated the anticancer effect of the DDS.

[Progress of researches on mechanisms of acupuncture therapy underlying improving myocardial ischemia and the future approach for in-depth study on its mechanisms from epigenetics].

As an important content of alternative and complementary medicine, acupuncture therapy has been proved to be effective in relieving myocardial ischemia (MI). Authors of the present paper review recent progress of researches on acupuncture therapy in resisting MI from 1) improving cardiovascular function and promoting angiogenesis, and 2) protecting myocardial cells from further injury and reducing cellular apoptosis at different pathological stages of MI. Moreover, the authors discuss the characteristics of epigenetic regulation in the process of MI and cardiac repair including the methylating of DNA, modification of histone, remodeling of the chromatin, and micro-RNA expression, mediating cellular apoptosis, regeneration of myocardial blood vessels, etc. The authors hold that future studies on the underlying mechanisms of acupuncture therapy in the prevention and treatment of MI from epigenetics may be a new approach and a new direction.

Acupuncture promotes angiogenesis after myocardial ischemia through H3K9 acetylation regulation at VEGF gene.

BACKGROUND: Acupuncture exerts cardioprotective effects on several types of cardiac injuries, especially myocardial ischemia (MI), but the mechanisms have not yet been well elucidated. Angiogenesis mediated by VEGF gene expression and its modification through histone acetylation has been considered a target in treating myocardial ischemia. This study aims to exam whether modulation of angiogenesis through H3K9 acetylation regulation at VEGF gene is one possible cardioprotective mechanism of acupuncture. RESULTS: We generated rat MI models by ligating the left anterior descending coronary artery and applied electroacupuncture (EA) treatment at the Neiguan (PC6) acupoint. Our results showed that acupuncture reversed the S-T segment change, reduced Q-wave area, decreased CK, CK-MB, LDH levels, mitigated myocardial remodeling, and promoted microvessel formation in the MI heart. RNA-seq analysis showed that VEGF-induced angiogenesis signaling was involved in the modulation of EA. Western blot results verified that the protein expressions of VEGF, Ras, phospho-p44/42 MAPK, phospho-p38 MAPK, phospho-SAPK/JNK and Akt, were all elevated significantly by EA treatment in the MI heart. Furthermore, increased H3K9 acetylation was also observed according with the VEGF. ChIP assay confirmed that EA treatment could notably stimulate the recruitment of H3K9ace at the VEGF promoter. CONCLUSIONS: Our study demonstrates for the first time that acupuncture can effectively up-regulate VEGF expression through H3K9 acetylation modification directly at the VEGF promoter and hence activate VEGF-induced angiogenesis in rat MI models. We employed high throughput sequencing in this study and, for the first time, generated genome-wide gene expression profiles both in the rat MI model and in acupuncture treatment.