ABSTRACT
In the field of chiral amine synthesis, ω-amine transaminase (ω-ATA) is one of the most established enzymes capable of asymmetric amination under optimal conditions. However, the applicability of ω-ATA toward more non-natural complex molecules remains limited due to its low transamination activity, thermostability, and narrow substrate scope. Here, by employing a combined approach of computational virtual screening strategy and combinatorial active-site saturation test/iterative saturation mutagenesis strategy, we have constructed the best variant M14C3-V5 (M14C3-V62A-V116S-E117I-L118I-V147F) with improved ω-ATA from Aspergillus terreus (AtATA) activity and thermostability toward non-natural substrate 1-acetylnaphthalene, which is the ketone precursor for producing the intermediate (R)-(+)-1-(1-naphthyl)ethylamine [(R)-NEA] of cinacalcet hydrochloride, showing activity enhancement of up to 3.4-fold compared to parent enzyme M14C3 (AtATA-F115L-M150C-H210N-M280C-V149A-L182F-L187F). The computational tools YASARA, Discovery Studio, Amber, and FoldX were applied for predicting mutation hotspots based on substrate-enzyme binding free energies and to show the possible mechanism with features related to AtATA structure, catalytic activity, and stability in silico analyses. M14C3-V5 achieved 71.8% conversion toward 50 mM 1-acetylnaphthalene in a 50 mL preparative-scale reaction for preparing (R)-NEA. Moreover, M14C3-V5 expanded the substrate scope toward aromatic ketone compounds. The generated virtual screening strategy based on the changes in binding free energies has successfully predicted the AtATA activity toward 1-acetylnaphthalene and related substrates. Together with experimental data, these approaches can serve as a gateway to explore desirable performances, expand enzyme-substrate scope, and accelerate biocatalysis.IMPORTANCEChiral amine is a crucial compound with many valuable applications. Their asymmetric synthesis employing ω-amine transaminases (ω-ATAs) is considered an attractive method. However, most ω-ATAs exhibit low activity and stability toward various non-natural substrates, which limits their industrial application. In this work, protein engineering strategy and computer-aided design are performed to evolve the activity and stability of ω-ATA from Aspergillus terreus toward non-natural substrates. After five rounds of mutations, the best variant, M14C3-V5, is obtained, showing better catalytic efficiency toward 1-acetylnaphthalene and higher thermostability than the original enzyme, M14C3. The robust combinational variant acquired displayed significant application value for pushing the asymmetric synthesis of aromatic chiral amines to a higher level.
Subject(s)
Aspergillus , Enzyme Stability , Transaminases , Transaminases/metabolism , Transaminases/genetics , Transaminases/chemistry , Aspergillus/enzymology , Aspergillus/genetics , Substrate Specificity , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Amines/metabolism , Amines/chemistry , Catalytic DomainABSTRACT
OBJECTIVE: In this study we aimed to determine the impact of human urine derived stem cells (USC) and genetically modified USC that were designed to overexpress myogenic growth factor IGF1 (USCIGF), on the regenerative capacity of cardiotoxin (CTX)-injured murine skeletal muscle. METHODS: We overexpressed IGF1 in USC and investigated the alterations in myogenic capacity and regenerative function in cardiotoxin-injured muscle tissues. RESULTS: Compared with USC alone, USCIGF1 activated the IGF1-Akt-mTOR signaling pathway, significantly improved myogenic differentiation capacity in vitro, and enhanced the secretion of myogenic growth factors and cytokines. In addition, IGF1 overexpression increased the ability of USC to fuse with skeletal myocytes to form myotubes, regulated the pro-regenerative immune response and inflammatory cytokines, and increased myogenesis in an in vivo model of skeletal muscle injury. CONCLUSION: Overall, USC genetically modified to overexpress IGF1 significantly enhanced skeletal muscle regeneration by regulating myogenic differentiation, paracrine effects, and cell fusion, as well as by modulating immune responses in injured skeletal muscles in vivo. This study provides a novel perspective for evaluating the myogenic function of USC as a nonmyogenic cell source in skeletal myogenesis. The combination of USC and IGF1 expression has the potential to provide a novel efficient therapy for skeletal muscle injury and associated muscular defects in patients with urinary incontinence.
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Boron-Nitrogen-embedded polycyclic aromatic hydrocarbons (BN-PAHs) as novel π-conjugated systems have attracted immense attention owing to their superior optoelectronic properties. However, constructing long-range ordered supramolecular assemblies based on BN-PAHs remains conspicuously scarce, primarily attributed to the constraints arising from coordinating multiple noncovalent interactions and the intrinsic characteristics of BN-PAHs, which hinder precise control over delicate self-assembly processes. Herein, we achieve the successful formation of BN-PAH-based controllable hierarchical assemblies through synergistically leveraged cation-π and C-H···π interactions. By carefully adjusting the solvent conditions in two progressive assembly hierarchies, the one-dimensional (1D) supramolecular assemblies with "rigid yet flexible" assembled units are first formed by cation-π interactions, and then they can be gradually fused into two-dimensional (2D) structures under specific C-H···π interactions, thus realizing the precise control of the transformation process from BN-PAH-based 1D primary structures to 2D higher-order assemblies. The resulting 2D-BNSA, characterized by enhanced electrical conductivity and ordered 2D layered structure, provides anchoring and dispersion sites for loading two appropriate nanocatalysts, thus facilitating the efficient photocatalytic CO2 reduction (with a remarkable CH4 evolution rate of 938.7 µmol g-1 h-1) and electrocatalytic acetylene semihydrogenation (reaching a Faradaic efficiency for ethylene up to 98.5%).
ABSTRACT
Molecules with nonplanar architectures are highly desirable due to their unique topological structures and functions. We report here the synthesis of two molecular containers (1 â 3Br- and 1 â 3Cl-), which utilize intramolecular cation-π interactions to enforce macrocylic arrangements and exhibit high binding affinity and luminescent properties. Remarkably, the geometry of the cation-π interaction can be flexibly tailored to achieve a precise ring arrangement, irrespective of the angle of the noncovalent bonds. Additionally, the C-Hâ â â Br- hydrogen bonds within the container are also conducive to stabilizing the bowl-shaped conformation. These bowl-shaped conformations were confirmed both in solution through NMR spectroscopy and in the solid state by X-ray studies. 1 â 3Br- shows high binding affinity and selectivity: F->Cl-, through C-Hâ â â X- (X=F, Cl) hydrogen bonds. Additionally, these containers exhibited blue fluorescence in solution and yellow room-temperature phosphorescence (RTP) in the solid state. Our findings illustrate the utility of cation-π interactions in designing functional molecules.
ABSTRACT
Clinical deployment of oligonucleotides requires delivery technologies that improve stability, target tissue accumulation and cellular internalization. Exosomes show potential as ideal delivery vehicles. However, an affordable generalizable system for efficient loading of oligonucleotides on exosomes remain lacking. Here, we identified an Exosomal Anchor DNA Aptamer (EAA) via SELEX against exosomes immobilized with our proprietary CP05 peptides. EAA shows high binding affinity to different exosomes and enables efficient loading of nucleic acid drugs on exosomes. Serum stability of thrombin inhibitor NU172 was prolonged by exosome-loading, resulting in increased blood flow after injury in vivo. Importantly, Duchenne Muscular Dystrophy PMO can be readily loaded on exosomes via EAA (EXOEAA-PMO). EXOEAA-PMO elicited significantly greater muscle cell uptake, tissue accumulation and dystrophin expression than PMO in vitro and in vivo. Systemic administration of EXOEAA-PMO elicited therapeutic levels of dystrophin restoration and functional improvements in mdx mice. Altogether, our study demonstrates that EAA enables efficient loading of different nucleic acid drugs on exosomes, thus providing an easy and generalizable strategy for loading nucleic acid therapeutics on exosomes.
Subject(s)
Exosomes , Muscular Dystrophy, Duchenne , Animals , Mice , Dystrophin/genetics , Mice, Inbred mdx , Exosomes/metabolism , Morpholinos/metabolism , Morpholinos/pharmacology , Morpholinos/therapeutic use , Muscular Dystrophy, Duchenne/drug therapy , Muscular Dystrophy, Duchenne/genetics , Oligonucleotides/metabolism , Oligonucleotides/therapeutic useABSTRACT
Following 3R (reduction, refinement, and replacement) principles, we employed the rat liver S9 fraction to mimic liver metabolism of curcumol having high in vitro IC50 on cancer cells. In HCT116 and HT29 colon cancer cells, the metabolites of curcumol by S9 fraction exerted more enhanced activity in inducing cell cycle arrest and apoptosis via regulating the expression of cyclin D1, CDK1, p21, PARP and Bcl-2 than curcumol. In addition, oral administration of curcumol at 4 mg/kg BW significantly suppressed the development of colon tumor induced by azoxymethane/dextran sulfate sodium, and induced cell cycle arrest and apoptosis in tumor tissues. In mass analysis, curcumenol and curzerene were identified as the metabolites of curcumol by S9 fraction metabolism. Taken together, curcumol metabolites showed the enhanced suppressive effect on colon cancer, suggesting that S9 fraction can be considered as simple, fast, and bio-mimicking platform for the screening of chemical libraries on different chronic diseases.
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Helicenes with persistent luminescence have received relatively little attention, despite their demonstrated highly efficient intersystem crossing (ISC) from the excited singlet to the triplet state. Herein, we designed a series of ortho-fused aromatics by combining dithieno[2,3-b:3',2'-d]thiophene (DTT) with annulated benzene fragments, denoted as TB[n]H (n = 3-8), to achieve persistent luminescence. Wherein, thia[n]helicenes (n = 5-8) exhibited intense phosphorescence with millisecond-range lifetimes (τp) at 77 K. Particularly interesting was the observation that the odd-numbered ring helicenes displayed longer τp values than their neighboring even-numbered counterparts. Notably, TB[7]H showcased the longest τp of 628 ms. This phenomenon can be attributed to the more favorable ISC channels and stronger spin-orbital coupling (SOC) of old-numbered helicenes than even-numbered ones. Furthermore, both conformers of TB[7]H exhibited significant circularly polarized phosphorescent (CPP) responses, with luminescence dissymmetry factors (glum) of 0.015 and -0.014. These discoveries suggest that thiahelicenes may be a specific class of organic phosphorescent and CPP materials.
ABSTRACT
Immobilized enzymes exhibit favorable advantages in biocatalysis, such as high operation stability, feasible reusability, and improved organic solvents tolerance. Herein, an immobilized ω-amine transaminase AtATA@MWCNTs-NH2 is successfully prepared using amino modified multi-walled carbon nanotubes as carrier and glutaraldehyde as crosslinker. Under the optimum immobilization conditions, the activity recovery is 78.7%. Compared with purified enzyme AtATA, AtATA@MWCNTs-NH2 possesses superior stability, even in harsh conditions (e.g., high temperature, acidic or alkali environment, and different kind of organic solvents). To simplify the separation and extraction of products, we choose methanol (10%, v/v) as the cosolvent, replacing DMSO (20%, v/v) in our previous work, for the catalytic reaction of AtATA@MWCNTs-NH2. AtATA@MWCNTs-NH2 can be used for stereoselective synthesis (R)-(+)- 1(1-naphthyl)ethylamine ((R)-NEA) for 15 cycles, with the e.e.p (enantiomeric excess) > 99.5%. The catalytic process of AtATA@MWCNTs-NH2 achieves cycle production of (R)-NEA using methanol as cosolvent.
Subject(s)
Nanotubes, Carbon , Naphthalenes , Amines , Transaminases , Methanol , Enzymes, Immobilized , Ethylamines , SolventsABSTRACT
[This corrects the article DOI: 10.1007/s10068-022-01068-1.].
ABSTRACT
[This corrects the article DOI: 10.1007/s10068-022-01130-y.].
ABSTRACT
Chitosan/Hydroxyapatite composites, enriched with relatively active -NH2 and -OH groups, have emerged as promising adsorbents for heavy metal removal. In this study, we harnessed the potential of CS/HAP composites by developing monolithic PLA@CS/HAP filters utilizing 3D printing and freeze-drying techniques. These filters possess both macroscopic and microscopic porous structures, endowing them with exceptional capabilities for removing heavy metals from water. The adsorption properties of CS/HAP composites were explored by varying the dosage, duration, and initial concentrations of copper ions. The maximum adsorption capacity for Cu2+ was determined to be approximately 119+/-1 mg/g at the natural pH and 298 K. Notably, the monolithic PLA@CS/HAP filters demonstrated remarkable efficiency in the removal of copper ions, with 90% of copper ions effectively removed within a mere 2-h period in a cyclic adsorption experiment. Furthermore, the PLA@CS/HAP filters exhibited a robust dynamic Cu2+ removal capacity (80.8% or even better in less than 35 min) in a dynamic adsorption experiment. Importantly, all materials employed in this study were environmentally friendly. In summary, the PLA@CS/HAP filter offers advantages such as ease of preparation, eco-friendliness, versatility, and broad applicability in diverse wastewater treatment scenarios, thereby presenting a significant potential for practical implementation.
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Three S/Se-hetero[9]helicenes were synthesized by an assembly strategy of two building blocks, phenanthrene and ternary fused S/Se-heteroaromatic ring, and characterized by single-crystal X-ray diffraction analysis. Their phosphorescence emission gave a long-lived lifetime at the millisecond level. In addition, the high configurational stability of enantiomer (+)-[9]BH-1a was observed without change under both the conditions of 300 °C in the solid state for 18 h and 200 °C in solution of 1,2-dichlorobenzene for 10 h.
ABSTRACT
Poly(ethylene terephthalate) (PET) is one of the most widely used synthetic polyesters, however, its extensive use creates a long-term environmental burden. Unlike traditional recycling methods, biodegradation is a sustainable strategy. The emergence of PETase from Ideonella sakaiensis 201-F6 (IsPETase) has brought great potential for the industrialization of degradable PET. In this work, models of enzyme-substrate complexes with different degrees of polymerization were established to study the binding mode using molecular dynamics simulation. We found that the whole binding site can be further subdivided into three parts, including head, middle and tail binding regions. Most importantly, the presence of the middle region formed by both ends of Ser93 and Ser236 provides a potential possibility for the binding of substrates with different chain lengths, and exerts the self-regulation ability of enzymes to accommodate substrates. Meanwhile, the 'pocket bottom' Arg280 in the tail region echoes the 'pocket mouth' Trp185 in the head region, defining the substrate binding region. This work reveals the self-regulation of IsPETase, as well as the key residues for the substrate binding. The solution to these problems enables us to better understand the function of enzymes and design high-performance degradation enzymes, which is of great significance for industrial application research.
Subject(s)
Hydrolases , Self-Control , Hydrolases/chemistry , Polymerization , Protein Domains , Biodegradation, Environmental , Polyethylene Terephthalates/chemistryABSTRACT
ω-transaminase (ω-TA) is a natural biocatalyst that has good application potential in the synthesis of chiral amines. However, the poor stability and low activity of ω-TA in the process of catalyzing unnatural substrates greatly hampers its application. To overcome these shortcomings, the thermostability of (R)-ω-TA (AtTA) from Aspergillus terreus was engineered by combining molecular dynamics simulation assisted computer-aided design with random and combinatorial mutation. An optimal mutant AtTA-E104D/A246V/R266Q (M3) with synchronously enhanced thermostability and activity was obtained. Compared with the wild- type (WT) enzyme, the half-life t1/2 (35 â) of M3 was prolonged by 4.8-time (from 17.8 min to 102.7 min), and the half deactivation temperature (T1050) was increased from 38.1 â to 40.3 â. The catalytic efficiencies toward pyruvate and 1-(R)-phenylethylamine of M3 were 1.59- and 1.56-fold that of WT. Molecular dynamics simulation and molecular docking showed that the reinforced stability of α-helix caused by the increase of hydrogen bond and hydrophobic interaction in molecules was the main reason for the improvement of enzyme thermostability. The enhanced hydrogen bond of substrate with surrounding amino acid residues and the enlarged substrate binding pocket contributed to the increased catalytic efficiency of M3. Substrate spectrum analysis revealed that the catalytic performance of M3 on 11 aromatic ketones were higher than that of WT, which further showed the application potential of M3 in the synthesis of chiral amines.
Subject(s)
Amines , Transaminases , Transaminases/genetics , Transaminases/chemistry , Molecular Docking Simulation , Amines/chemistry , Pyruvic Acid/metabolism , Enzyme StabilityABSTRACT
BACKGROUND: Biocatalysis in high-concentration organic solvents has been applied to produce various industrial products with many advantages. However, using enzymes in organic solvents often suffers from inactivation or decreased catalytic activity and stability. An R-selective ω-amine transaminase from Aspergillus terreus (AtATA) exhibited activity toward 1-acetylnaphthalene. However, AtATA displayed unsatisfactory organic solvent resistance, which is required to enhance the solubility of the hydrophobic substrate 1-acetylnaphthalene. So, improving the tolerance of enzymes in organic solvents is essential. MAIN METHODS AND RESULTS: The method of regional random mutation combined with combinatorial mutation was used to improve the resistance of AtATA in organic solvents. Enzyme surface areas are structural elements that undergo reversible conformational transitions, thus affecting the stability of the enzyme in organic solvents. Herein, three surface areas containing three loops were selected as potential mutation regions. And the "best" mutant T23I/T200K/P260S (M3) was acquired. In different concentrations of dimethyl sulfoxide (DMSO), the catalytic efficiency (kcat /Km ) toward 1-acetylnaphthalene and the stability (half-life t1/2 ) were higher than the wild-type (WT) of AtATA. The results of decreased Root Mean Square Fluctuation (RMSF) values via 20-ns molecular dynamics (MD) simulations under 15%, 25%, 35%, and 45% DMSO revealed that mutant M3 had lower flexibility, acquiring a more stable protein structure and contributing to its organic solvents stability than WT. Furthermore, M3 was applied to convert 1-acetylnaphthalene for synthesizing (R)-(+)-1(1-naphthyl)-ethylamine ((R)-NEA), which was an intermediate of Cinacalcet Hydrochloride for the treatment of secondary hyperthyroidism and hypercalcemia. Moreover, in a 20-mL scale-up experiment, 10 mM 1-acetylnaphthalene can be converted to (R)-NEA with 85.2% yield and a strict R-stereoselectivity (enantiomeric excess (e.e.) value >99.5%) within 10 h under 25% DMSO. CONCLUSION: The beneficial mutation sites were identified to tailor AtATA's organic solvents stability via regional random mutation. The "best" mutant T23I/T200K/P260S (M3) holds great potential application for the synthesis of (R)-NEA.
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Perilla frutescens is an annual herbaceous plant widely cultivated for oil production in China, Japan, and Korea. In this study, we investigated the effect of perilla oil (PO) on thrombosis induced by collagen and epinephrine (CE) in rats. The oral administration of PO significantly increased prothrombin time (PT) and activated partial thromboplastin time (aPTT) in the blood plasma and inhibited the expression of cells adhesion markers (CAMs) such as intercellular CAM-1 (ICAM-1), vascular CAM (VCAM-1), E-selectin and P-selectin in the aorta tissue. Furthermore, pulmonary occlusion induced by CE in rats was suppressed by PO. α-Linolenic acid (ALA) was quantified at 60.14 ± 2.50 g/100 g of PO, and its oral administration at the same concentration with that in PO exerted the similar effect on PT, aPTT, ICAM-1, VCAM-1, E-selectin and P-selectin in CE-induced thrombosis rats. Taken together, PO and ALA significantly ameliorated thrombosis by regulating CAMs.
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BACKGROUND: The capacity of self-renewal and multipotent differentiation makes mesenchymal stem cells (MSC) one of the most widely investigated cell lines in preclinical studies as cell-based therapies. However, the low survival rate and poor homing efficiency of MSCs after transplantation hinder the therapeutic application. Exosomes derived from MSCs have shown promising therapeutic potential in many diseases. However, the heterogeneity of MSCs may lead to differences in the function of secreting exosomes. In this study, the therapeutic effects of hUC-Exos and hFP-Exos on the DSS-induced colitis mouse model were investigated. METHODS: The colitis mouse models were randomly divided into four groups: (1) DSS administered for 7 days and euthanasia (DSS7D), (2) DSS administered for 7 days and kept for another 7 days without any treatment (DSS14D), (3) DSS administered for 7 days and followed with hUC-EVs infusion for 7 days (hUC-EVs) and (4) DSS administered for 7 days and followed with hFP-EVs infusion for 7 days (hFP-EVs). We analyzed colon length, histopathology, Treg cells, cytokines and gut microbiota composition in each group. RESULTS: A large amount of IL-6, IL-17 and IFN-γ were produced along with the decrease in the number of CD4 + Foxp3 + and CD8 + Foxp3 + cells in DSS7D group, which indicated that Th17 cells were activated and Treg cells were suppressed. We found that the number of CD4 + Foxp3 + and CD8 + Foxp3 + cells increased in order to suppress inflammation, but the length of colon did not recover and the symotoms were worsened of the colonic tissue in DSS14D group. The subsequent infusion of either hUC-Exos or hFP-Exos mediated the transformation of Treg and Th17 cells in colitis mice to maintain immune balance. The infusion of hUC-Exos and hFP-Exos also both reduced the abundance of pro-inflammatory intestinal bacterial such as Verrucomicrobia and Akkermansia muciniphila to improve colitis. CONCLUSIONS: We found that Foxp3 + Treg cells can inhibit the inflammatory response, and the over-activated Treg cells can still further damage the intestinal mucosa. hUC-Exos and hFP-Exos can control inflammation by regulating the balance between Th17 cells and Treg cells. Decreased inflammatory response improved the structure of colon wall in mice and reduced the abundance of pro-inflammatory bacteria in the intestine. The improvement of intestinal wall structure provides conditions for the reproduction of beneficial bacteria, which further contributes to the reduction of colitis.
Subject(s)
Colitis , Exosomes , Gastrointestinal Microbiome , Mice , Animals , T-Lymphocytes, Regulatory , Exosomes/pathology , Colitis/chemically induced , Colitis/therapy , Inflammation , Disease Models, Animal , Mice, Inbred C57BL , Dextran Sulfate/adverse effects , Th17 Cells , Forkhead Transcription Factors/geneticsABSTRACT
Hypoxia-inducible factor-1 (HIF-1) is an [Formula: see text]/[Formula: see text] heterodimeric transcription factor. In normal mammalian cells, HIF-1[Formula: see text] is hydroxylated and degraded upon biosynthesis. However, HIF-1[Formula: see text] is frequently expressed in cancer and adds to cancer malignancy. In this study, we investigated whether green tea-derived epigallocatechin-3-gallate (EGCG) decreased HIF-1[Formula: see text] in pancreatic cancer cells. After MiaPaCa-2 and PANC-1 pancreatic cancer cells were exposed to EGCG in vitro, we performed a Western blot to determine native and hydroxylated HIF-1[Formula: see text], which was in turn used to assess HIF-1[Formula: see text] production. In order to assess HIF-1[Formula: see text] stability, we determined the HIF-1[Formula: see text] after MiaPaCa-2 and PANC-1 cells were switched from hypoxia to normoxia. We found that EGCG decreased both production and stability of HIF-1[Formula: see text]. Further, the EGCG-induced decrease in HIF-1[Formula: see text] reduced intracellular glucose transporter-1 and glycolytic enzymes and attenuated glycolysis, ATP production, and cell growth. Because EGCG is known to inhibit cancer-induced insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R), we created three MiaPaCa-2 sublines whose IR, IGF1R, and HIF-1[Formula: see text] were decreased using RNA interference. From wild-type MiaPaCa-2 cells and these sublines, we found evidence that suggested that the EGCG-induced inhibition of HIF-1[Formula: see text] was both dependent on and independent of IR and IGF1R. In vivo, we transplanted wild-type MiaPaCa-2 cells in athymic mice and treated the mice with EGCG or vehicle. When the resulting tumors were analyzed, we found that EGCG decreased tumor-induced HIF-1[Formula: see text] and tumor growth. In conclusion, EGCG decreased HIF-1[Formula: see text] in pancreatic cancer cells and sabotaged the cells. The anticancer effects of EGCG were both dependent on and independent of IR and IGF1R.
Subject(s)
Hypoxia-Inducible Factor 1 , Pancreatic Neoplasms , Animals , Mice , Hypoxia-Inducible Factor 1/genetics , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Hypoxia , Mammals , Pancreatic NeoplasmsABSTRACT
Biological proton channels play important roles in the delicate metabolism process, and have led to great interest in mimicking selective proton transport. Herein, we designed a bioinspired proton transport membrane by incorporating flexible 14-crown-4 (14C4) units into rigid frameworks of polyimine films by an interfacial Schiff base reaction. The Young's modulus of the membrane reaches about 8.2â GPa. The 14C4 units could grab water, thereby forming hydrogen bond-water networks and acting as jumping sites to lower the energy barrier of proton transport. The molecular chains present a vertical orientation to the membrane, and the ions travel between the quasi-planar molecular sheets. Furthermore, the 14C4 moieties could bond alkali ions through host-guest interactions. Thus, the ion conductance follows H+ â«K+ >Na+ >Li+ , and an ultrahigh selectivity of H+ /Li+ (ca. 215) is obtained. This study provides an effective avenue for developing ion-selective membranes by embedding macrocycle motifs with inherent cavities.
ABSTRACT
Nonhuman primates (NHPs) have been considered as the best models for biomedical research due to their high similarities in genomic, metabolomic, physiological and pathological features to humans. However, generation of genetically modified NHPs through traditional methods, such as microinjection into the pronuclei of one-cell embryos, is prohibitive due to the targeting efficiency and the number of NHPs needed as oocyte/zygote donors. Using spermatogonial stem cells (SSCs) as the target of gene editing, producing gene-edited sperm for fertilization, is proven to be an effective way to establish gene editing animal disease models. In this experiment, we used ultrasound to guide the echo dense injection needle into the rete testis space, allowing the EGFP lentivirus to be slowly injected at positive pressure from the rete testis into seminiferous tubules. We found Thy1 can be used as a surface marker of cynomolgus monkey SSCs, confirming that SSCs carry the GFP gene. Finally, we successfully obtained transgenic sperm, with a similar freezing and recovery rate to that of WT animals.