Maleimide conjugated PEGylated liposomal antibiotic to combat multi-drug resistant Escherichia coli and Klebsiella pneumoniae with enhanced wound healing potential.

Antibiotic resistance is a significant threat, leaving us vulnerable to bacterial infections. Novel strategies are needed to combat bacterial resistance beyond discovering new antibiotics. This research focuses on using maleimide conjugated PEGylated liposomes (Mal-PL-Ab) to individually encapsulate a variety of antibiotics (ceftriaxone, cephalexin, doxycycline, piperacillin, ampicillin, and ceftazidime) and enhance their delivery against multi-drug resistant (MDR) bacteria like Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). Mal-PL-Ab, with an average size of 84.2 nm ± 4.32 nm, successfully encapsulated these antibiotics with an encapsulation efficiency of 37.73 ± 3.19%. Compared to non-PEGylated liposomes (L-Ab), Mal-PL-Ab exhibited reduced toxicity in human dermal cells, emphasizing the importance of PEGylation in minimizing adverse effects. Mal-PL-Ab significantly decreased the minimum inhibitory concentration (MIC) values against both E. coli and K. pneumoniae by 9.33-fold and eightfold reduction (compared to non-PEGylated liposomes with 2.33-fold and 2.33fold reduction), respectively, indicating enhanced efficacy against MDR strains. Furthermore, in vitro scratch assay and gene expression analysis of human dermal fibroblast revealed that Mal-PL-Ab promoted cell proliferation, migration, and wound healing through upregulation of cell cycle, DNA repair, and angiogenesis-related genes. Harnessing the power of encapsulation, Mal-PL-Ab presents a novel avenue for enhanced antibiotic delivery and wound healing, potentially transcending the limitations of traditional options.

Synthesis of 3,4-Disubstituted Maleimide Derivatives via Phosphine-Catalyzed Isomerization of α-Succinimide-Substituted Allenoates Cascade γ'-Addition with Aryl Imines.

3,4-disubstituted maleimides find wide applications in various pharmacologically active compounds. This study presents a highly effective approach for synthesizing derivatives of 3,4-disubstituted maleimides through the direct isomerization of α-succinimide-substituted allenoates, followed by a cascade γ'-addition and aryl imines using PR3 as a catalyst. The resulting series of 3,4-disubstituted maleimides exhibited excellent stereoselectivities, achieving yields of up to 86%. To our knowledge, the phosphine-mediated γ'-addition reaction of allenoates is seldom reported.

On-Demand Thio-Succinimide Hydrolysis for the Assembly of Stable Protein-Protein Conjugates.

Chemical post-translational protein-protein conjugation is an important technique with growing applications in biotechnology and pharmaceutical research. Maleimides represent one of the most widely employed bioconjugation reagents. However, challenges associated with the instability of first- and second-generation maleimide technologies are yet to be fully addressed. We report the development of a novel class of maleimide reagents that can undergo on-demand ring-opening hydrolysis of the resulting thio-succinimide. This strategy enables rapid post-translational assembly of protein-protein conjugates. Thio-succinimide hydrolysis, triggered upon application of chemical, photochemical, or enzymatic stimuli, allowed homobifunctional bis-maleimide reagents to be applied in the production of stable protein-protein conjugates, with complete temporal control. Bivalent and bispecific protein-protein dimers constructed from small binders targeting antigens of oncological importance, PD-L1 and HER2, were generated with high purity, stability, and improved functionality compared to monomeric building blocks. The modularity of the approach was demonstrated through elaboration of the linker moiety through a bioorthogonal propargyl handle to produce protein-protein-fluorophore conjugates. Furthermore, extending the functionality of the homobifunctional reagents by temporarily masking reactive thiols included in the linker allowed the assembly of higher order trimeric and tetrameric single-domain antibody conjugates. The potential for the approach to be extended to proteins of greater biochemical complexity was demonstrated in the production of immunoglobulin single-domain antibody conjugates. On-demand control of thio-succinimide hydrolysis combined with the facile assembly of chemically defined homo- and heterodimers constitutes an important expansion of the chemical methods available for generating stable protein-protein conjugates.

Structure-activity relationship of dual inhibitors containing maleimide and imidazole motifs against glutaminyl cyclase and glycogen synthase kinase-3ß.

Alzheimer's disease (AD) is a major cause of dementia and one of the most common chronic diseases affecting the aging population. Because AD is considered a public health priority, there is a critical need to discover novel and effective agents for the treatment of this condition. In view of the known contribution of up-regulated glutaminyl cyclase (QC) and glycogen synthase kinase-3ß (GSK-3ß) to the initiation of AD, we previously evaluated a series of dual inhibitors containing maleimide and imidazole motifs as potential anti-AD agents. Here, we assessed another series of hybrids containing maleimide and imidazole motifs to gain an in-depth understanding of the structure-activity relationship (SAR). Based on the primary screening, the introduction of 5-methyl imidazole at one side of the molecule did not enhance the QC-specific inhibitory activity of these hybrids (2, IC50 = 1.22 µM), although the potency was increased by 2' substitution on the maleimide motif at the other side of the molecule. Interestingly, compounds containing 5-methyl imidazole exhibited stronger GSK-3ß-specific inhibitory activity (2, IC50 = 0.0021 µM), and the electron-withdrawing group and 2' and 3' substitution were favorable. Further investigation of substitutions on the maleimide motif in compounds 14-35 revealed that QC-specific inhibition in the presence of piperidine was improved by introduction of a methoxy group (R2). Increasing the linker length and introduction of a methoxy group (R2) also increased the GSK-3ß-specific inhibitory potency. These findings were further confirmed by molecular docking analysis of 33 and 24 with QC and GSK-3ß. Overall, these hybrids exhibited enhanced inhibitory potency against both QC and GSK-3ß, highlighting an important strategy for improving the potency of hybrids as dual-targeting anti-AD agents.

Synthesis and evaluation of antibody-drug conjugates with high drug-to-antibody ratio using dimaleimide-DM1 as a linker- payload.

The notable characteristics of recently emerged Antibody-Drug Conjugates (ADCs) encompass the targeting of Human Epidermal growth factor Receptor 2 (HER2) through monoclonal antibodies (mAbs) and a high ratio of drug to antibody (DAR). The achievements of Kadcyla® (T-DM1) and Enhertu® (T-Dxd) have demonstrated that HER2-targeting antibodies, such as trastuzumab, have shown to be competitive in terms of efficacy and price for development. Furthermore, with the arrival of T-Dxd and Trodelvy®, high-DAR (7-8) ADCs, which differ from the moderate DAR (3-4) ADCs that were formerly regarded as conventional, are being acknowledged for their worth. Following this trend of drug development, we endeavored to develop a high-DAR ADC using a straightforward approach involving the utilization of DM1, a highly potent substance, in combination with the widely recognized trastuzumab. To achieve a high DAR, DM1 was conjugated to reduced cysteine through the simple design and synthesis of various dimaleimide linkers with differing lengths. Using LC and MS analysis, we have demonstrated that our synthesis methodology is uncomplicated and efficacious, yielding trastuzumab-based ADCs that exhibit a remarkable degree of uniformity. These ADCs have been experimentally substantiated to exert an inhibitory effect on cancer cells in vitro, thus affirming their value as noteworthy additions to the realm of ADCs.

Design, synthesis and biological evaluation of indoline-maleimide conjugates as potential antitumor agents for the treatment of colorectal cancer.

An efficient protocol for direct coupling of maleimides and indolines at the C7-position was achieved under Rh(III) catalysis. Thirty four novel indoline-maleimide conjugates were prepared in good to excellent yields using this method. All compounds were evaluated for their anti-proliferative effect against colorectal cell lines. Among them, compound 3ab showed the most potent anti-proliferative activity against the CRC cells, and displayed low toxicity in the normal cell. Further investigation indicated that 3ab could effectively suppress the proliferation and migration of CRC cells, along with inducing cell cycle arrest and apoptosis. Mechanistic studies revealed that compound 3ab inhibited the proliferation of CRC cells via suppressing the AKT/GSK-3ß pathway. In vivo evaluation demonstrated remarkable antitumor effect of 3ab (10 mg/kg) in the HCT116 xenograft model with no obvious toxicity, which is superior to that of 5-Fluorouracil (20 mg/kg). Therefore, conjugate 3ab could be considered as a potential CRC therapy agent for further development.

Promotion and Detection of Cell-Cell Interactions through a Bioorthogonal Approach.

Manipulation of cell-cell interactions via cell surface modification is crucial in tissue engineering and cell-based therapy. To be able to monitor intercellular interactions, it can also provide useful information for understanding how the cells interact and communicate. We report herein a facile bioorthogonal strategy to promote and monitor cell-cell interactions. It involves the use of a maleimide-appended tetrazine-caged boron dipyrromethene (BODIPY)-based fluorescent probe and a maleimide-substituted bicyclo[6.1.0]non-4-yne (BCN) to modify the membrane of macrophage (RAW 264.7) and cancer (HT29, HeLa, and A431) cells, respectively, via maleimide-thiol conjugation. After modification, the two kinds of cells interact strongly through inverse electron-demand Diels-Alder reaction of the surface tetrazine and BCN moieties. The coupling also disrupts the tetrazine quenching unit, restoring the fluorescence emission of the BODIPY core on the cell-cell interface, and promotes phagocytosis. Hence, this approach can promote and facilitate the detection of intercellular interactions, rendering it potentially useful for macrophage-based immunotherapy.

Apigenin alleviates doxorubicin-induced myocardial pyroptosis by inhibiting glycogen synthase kinase-3ß in vitro and in vivo.

Apigenin, a natural flavonoid compound found in chamomile (Matricaia chamomilla L.) from the Asteraceae family, has been shown in our previous study to possess antimyocardial hypertrophy and anti-cardiac fibrosis effects. However, its effects and mechanisms on the pyroptosis of cardiomyocytes induced by doxorubicin (DOX) are poorly understood. The objective of this study was to investigate the role of GSK-3ß and the effects of apigenin in DOX-induced cardiotoxicity. H9c2 cells stimulated with DOX were treated with SB216763 and apigenin. Additionally, a mouse model of DOX-induced cardiotoxicity was prepared and further treated with apigenin and SB216763 for 30 days. The findings revealed that treatment with SB216763 or apigenin resulted in a significant reduction in the levels of pyroptosis-related factors. Furthermore, the phosphorylation of GSK-3ß was enhanced while the phosphorylation of nuclear factor-kB (NF-κB) p65 was reduced following treatment with either SB216763 or apigenin. Conversely, the effects of apigenin treatment were nullified in siRNA-GSK-3ß-transfected cells. Results from computer simulation and molecular docking analysis supported that apigenin could directly target the regulation of GSK-3ß. Therefore, our study confirmed that the inhibition of GSK-3ß and treatment with apigenin effectively suppressed the pyroptosis of cardiomyocytes in both DOX-stimulated H9c2 cells and mice. These benefits may be attributed in part to the decrease in GSK-3ß expression and subsequent reduction in NF-κB p65 activation. Overall, our findings revealed that the pharmacological targeting of GSK-3ß may offer a promising therapeutic approach for alleviating DOX-induced cardiotoxicity.

In situ crosslinkable multi-functional and cell-responsive alginate 3D matrix via thiol-maleimide click chemistry.

In vivo, cells interact with the extracellular matrix (ECM), which provides a multitude of biophysical and biochemical signals that modulate cellular behavior. Inspired by this, we explored a new methodology to develop a more physiomimetic polysaccharide-based matrix for 3D cell culture. Maleimide-modified alginate (AlgM) derivatives were successfully synthesized using DMTMM to activate carboxylic groups. Thiol-terminated cell-adhesion peptides were tethered to the hydrogel network to promote integrin binding. Rapid and efficient in situ hydrogel formation was promoted by thiol-Michael addition "click" chemistry via maleimide reaction with thiol-flanked protease-sensitive peptides. Alginate derivatives were further ionically crosslinked by divalent ions present in the medium, which led to greater stability and allowed longer cell culture periods. By tailoring alginate's biofunctionality we improved cell-cell and cell-matrix interactions, providing an ECM-like 3D microenvironment. We were able to systematically and independently vary biochemical and biophysical parameters to elicit specific cell responses, creating custom-made 3D matrices. DMTMM-mediated maleimide incorporation is a promising approach to synthesizing AlgM derivatives that can be leveraged to produce ECM-like matrices for a broad range of applications, from in vitro tissue modeling to tissue regeneration.

Synthesis of Dendrimer-Like Molecules with Partial Carbon Chain via Iterative Single Unit Monomer Insertions.

Carbon-chain dendritic polymers hold unique properties and promising applications. However, synthesizing carbon-chain dendrimers, beyond conjugated ones, remains a challenge. Here, the use of the iterative single unit monomer insertion technique for synthesizing 2.5 generation partial-carbon-chain dendrimers (G2.5) is described, utilizing bismaleimide as the core, a maleimide-trithiocarbonate conjugate as the branching unit, and indene as the spacer unit, following a divergent growth strategy. The optimized conditions for synthesizing the maleimide-trithiocarbonate branching unit are a bismaleimide to trithiocarbonate ratio of 5:1 and a reaction time of 30 min. The structures are verified using 1H nuclear magnetic resonance, gel permeation chromatography, and matrix-assisted laser desorption/ionization-time of flight mass spectra. A four-arm star polymer is then synthesized using the G2.5 as the core. This synthesis of a partial-carbon-chain dendrimer establishes a foundational step toward creating all-carbon-chain ones and may open new application avenues in material science.

Development of a chromatographic method for optimizing the thiol-maleimide coupling of polyoxometalate-polymer hybrids.

The covalent attachment of polyoxometalates (POMs) to polymers has been developed as a strategic approach for the advancement of POM-based hybrid materials with versatile applications. In this study, we utilized thiol-maleimide Michael addition to investigate the kinetics and efficacy of the "one-to-one" conjugation between Keggin type POM and polystyrene. We explored the effects of solvent polarity, catalyst, molecular weight of PS and synthetic strategies on the reaction kinetics and efficiency, by means of reverse-phase high-performance liquid chromatography (RP-HPLC). A series of comparative analysis affirmed the superior efficiency of the one-pot method, particularly when facilitated by the addition of a high-polarity solvent and an excess of maleimide. These findings offer valuable insights into the intricate interplay between reaction conditions, kinetics, and selectivity in thiol-maleimide reactions of POMs and polymers. They hold profound implications for advancing the study of POM-based multifunctional materials and the synthesis of complex hybrid molecules.

Synthetic Lethality between Cohesin and WNT Signaling Pathways in Diverse Cancer Contexts.

Cohesin is a highly conserved ring-shaped complex involved in topologically embracing chromatids, gene expression regulation, genome compartmentalization, and genome stability maintenance. Genomic analyses have detected mutations in the cohesin complex in a wide array of human tumors. These findings have led to increased interest in cohesin as a potential target in cancer therapy. Synthetic lethality has been suggested as an approach to exploit genetic differences in cancer cells to influence their selective killing. In this study, we show that mutations in ESCO1, NIPBL, PDS5B, RAD21, SMC1A, SMC3, STAG2, and WAPL genes are synthetically lethal with stimulation of WNT signaling obtained following LY2090314 treatment, a GSK3 inhibitor, in several cancer cell lines. Moreover, treatment led to the stabilization of ß-catenin and affected the expression of c-MYC, probably due to the occupancy decrease in cohesin at the c-MYC promoter. Finally, LY2090314 caused gene expression dysregulation mainly involving pathways related to transcription regulation, cell proliferation, and chromatin remodeling. For the first time, our work provides the underlying molecular basis for synthetic lethality due to cohesin mutations and suggests that targeting the WNT may be a promising therapeutic approach for tumors carrying mutated cohesin.

A Golgi Apparatus-Targeted Photothermal Agent with Protein Anchoring for Enhanced Cancer Photothermal Therapy.

The Golgi apparatus (GA) is central in shuttling proteins from the endoplasmic reticulum to different cellular areas. Therefore, targeting the GA to precisely destroy its proteins through local heat could induce apoptosis, offering a potential avenue for effective cancer therapy. Herein, a GA-targeted photothermal agent based on protein anchoring is introduced for enhanced photothermal therapy of tumor through the modification of near-infrared molecular dye with maleimide derivative and benzene sulfonamide. The photothermal agent can actively target the GA and covalently anchor to its sulfhydryl proteins, thereby increasing its retention within the GA. Under laser irradiation, the heat generated by the photothermal agent efficiently disrupts sulfhydryl proteins in situ, leading to GA dysfunction and ultimately inducing cell apoptosis. In vivo experiments demonstrate that the photothermal agent can precisely treat tumors and significantly reduce side effects.

A monodispersed metal-complexing peptide-based polymer for mass cytometry enabling spectral applications.

We report the synthesis of a novel class of metal-complexing peptide-based polymers, which we name HyperMAPs (Hyper-loaded MetAl-complexed Polymers). The controlled solid-phase synthesis of HyperMAPs' scaffold peptide provides our polymer with a well-defined molecular structure that allows for an accurate on-design assembly of a wide variety of metals. The peptide-scaffold features a handle for direct conjugation to antibodies or any other biomolecules by means of a thiol-maleimide-click or aldehyde-oxime reaction, a fluorogenic moiety for biomolecule conjugation tracking, and a well-defined number of functional groups for direct incorporation of metal-chelator complexes. Since metal-chelator complexes are prepared in a separate reaction prior to incorporation to the peptide scaffold, polymers can be designed to contain specific ratios of metal isotopes, providing each polymer with a unique CyTOF spectral fingerprint. We demonstrate the complexing of 21 different metals using two different chelators and provide evidence of the application of HyperMAPs on a 13 parameter CyTOF panel and compare its performance to monoisotopic metal-conjugated antibodies.

ICLAMP: a novel technique to explore adenosine deamination via inosine chemical labeling and affinity molecular purification.

Recent developments in sequencing and bioinformatics have advanced our understanding of adenosine-to-inosine (A-to-I) RNA editing. Surprisingly, recent analyses have revealed the capability of adenosine deaminase acting on RNA (ADAR) to edit DNA:RNA hybrid strands. However, edited inosines in DNA remain largely unexplored. A precise biochemical method could help uncover these potentially rare DNA editing sites. We explore maleimide as a scaffold for inosine labeling. With fluorophore-conjugated maleimide, we were able to label inosine in RNA or DNA. Moreover, with biotin-conjugated maleimide, we purified RNA and DNA containing inosine. Our novel technique of inosine chemical labeling and affinity molecular purification offers substantial advantages and provides a versatile platform for further discovery of A-to-I editing sites in RNA and DNA.

Mucoadhesive Thiolated Hyaluronic Acid/Pluronic F127 Nanogel Formation via Thiol-Maleimide Click Reaction for Intravesical Drug Delivery.

The development of nanocarriers to prolong the residence time and enhance the permeability of chemotherapeutic drugs on bladder mucosa is important in the postsurgery treatment of superficial bladder cancers (BCs). Here, the mucoadhesive HA-SH/PF127 nanogels composed of a temperature-sensitive Pluronic F127 (PF127) core and thiolated hyaluronic acid (HA-SH) shell were prepared by the emulsification/solvent evaporation method. The nanogels were constructed through the thiol-maleimide click reaction in the HA-SH aqueous side of the oil-water interface and self-oxidized cross-linking thiols between HA-SH. The HA-SH/PF127 nanogels prepared at different thiol-to-maleimide group molar ratios, water-to-oil volume ratios, and cross-linking reaction times were characterized regarding hydrodynamic diameter (Dh) and zeta potential (ζ), and the optimal formulation was obtained. The excellent mucoadhesive properties of the HA-SH/PF127 nanogels were evaluated by using the mucin particle method. Doxorubicin (DOX) was encapsulated in the PF127 core of DOX@HA-SH/PF127 nanogels with a high loading efficiency (87.5%) and sustained release from the nanogels in artificial urine. Ex vivo studies on porcine bladder mucosa showed that the DOX@HA-SH/PF127 nanogels enhanced the penetration of the DOX into the bladder mucosa without disrupting the mucus structure or the bladder tissue. A significant dose-dependent cytotoxic effect of DOX@HA-SH/PF127 nanogels on both T24 and MB49 cells was observed. The present study demonstrates that the mucoadhesive HA-SH/PF127 nanogels are a promising intravesical drug delivery system for superficial BC therapy.

Synthesis, anticancer activity, and molecular docking of half-sandwich iron(II) cyclopentadienyl complexes with maleimide and phosphine or phosphite ligands.

In these studies, we designed and investigated the potential anticancer activity of five iron(II) cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All complexes were characterized with spectroscopic analysis viz. NMR, FT-IR, ESI-MS, UV-Vis, fluorescence, XRD (for four complexes) and elemental analyses. For biological studies, we used three types of cells-normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and non-small-cell lung cancer A549 cells. We evaluated cell viability and DNA damage after cell incubation with these complexes. We observed that all iron(II) complexes were more cytotoxic for HL-60 cells than for A549 cells. The complex CpFe(CO)(P(OPh)3)(η1-N-maleimidato) 3b was the most cytotoxic with IC50 = 9.09 µM in HL-60 cells, IC50 = 19.16 µM in A549 and IC50 = 5.80 µM in PBM cells. The complex CpFe(CO)(P(Fu)3)(η1-N-maleimidato) 2b was cytotoxic only for both cancer cell lines, with IC50 = 10.03 µM in HL-60 cells and IC50 = 73.54 µM in A549 cells. We also found the genotoxic potential of the complex 2b in both types of cancer cells. However, the complex CpFe(CO)2(η1-N-maleimidato) 1 which we studied previously, was much more genotoxic than complex 2b, especially for A549 cells. The plasmid relaxation assay showed that iron(II) complexes do not induce strand breaks in fully paired ds-DNA. The DNA titration experiment showed no intercalation of complex 2b into DNA. Molecular docking revealed however that complexes CpFe(CO)(PPh3) (η1-N-maleimidato) 2a, 2b, 3b and CpFe(CO)(P(OiPr)3)(η1-N-maleimidato) 3c have the greatest potential to bind to mismatched DNA. Our studies demonstrated that the iron(II) complex 1 and 2b are the most interesting compounds in terms of selective cytotoxic action against cancer cells. However, the cellular mechanism of their anticancer activity requires further research.

The Osteocyte with SB216763-Activated Canonical Wnt Signaling Constructs a Multifunctional 4D Intelligent Osteogenic Module.

The enhancement of bioactivity in materials has become an important focus within the field of bone tissue engineering. Four-dimensional intelligent osteogenic module, an innovative fusion of 3D printing with the time axis, shows immense potential in augmenting the bioactivity of these materials, thereby facilitating autologous bone regeneration efficiently. This study focuses on novel bone repair materials, particularly bioactive scaffolds with a developmental osteogenic microenvironment prepared through 3D bioprinting technology. This research mainly creates a developmental osteogenic microenvironment named "DOME". This is primed by the application of a small amount of the small molecule drug SB216763, which activates canonical Wnt signaling in osteocytes, promoting osteogenesis and mineralization nodule formation in bone marrow stromal cells and inhibiting the formation of adipocytes. Moreover, DOME enhances endothelial cell migration and angiogenesis, which is integral to bone repair. More importantly, the DOME-PCI3D system, a 4D intelligent osteogenic module constructed through 3D bioprinting, stably supports cell growth (91.2% survival rate after 7 days) and significantly increases the expression of osteogenic transcription factors in bone marrow stromal cells and induces osteogenic differentiation and mineralization for 28 days. This study presents a novel approach for bone repair, employing 3D bioprinting to create a multifunctional 4D intelligent osteogenic module. This innovative method not only resolves challenges related to shape-matching and biological activity but also demonstrates the vast potential for applications in bone repair.

Inhibition of protein kinase C increases Prdm14 level to promote self-renewal of embryonic stem cells through reducing Suv39h-induced H3K9 methylation.

Inhibition of protein kinase C (PKC) efficiently promoted the self-renewal of embryonic stem cells (ESCs). However, information about the function of PKC inhibition remains lacking. Here, RNA-sequencing showed that the addition of Go6983 significantly inhibited the expression of de novo methyltransferases (Dnmt3a and Dnmt3b) and their regulator Dnmt3l, resulting in global hypomethylation of DNA in mouse ESCs. Mechanistically, PR domain-containing 14 (Prdm14), a site-specific transcriptional activator, partially contributed to Go6983-mediated repression of Dnmt3 genes. Administration of Go6983 increased Prdm14 expression mainly through the inhibition of PKCδ. High constitutive expression of Prdm14 phenocopied the ability of Go6983 to maintain` mouse ESC stemness in the absence of self-renewal-promoting cytokines. In contrast, the knockdown of Prdm14 eliminated the response to PKC inhibition and substantially impaired the Go6983-induced resistance of mouse ESCs to differentiation. Furthermore, liquid chromatography-mass spectrometry profiling and Western blotting revealed low levels of Suv39h1 and Suv39h2 in Go6983-treated mouse ESCs. Suv39h enzymes are histone methyltransferases that recognize dimethylated and trimethylated histone H3K9 specifically and usually function as transcriptional repressors. Consistently, the inhibition of Suv39h1 by RNA interference or the addition of the selective inhibitor chaetocin increased Prdm14 expression. Moreover, chromatin immunoprecipitation assay showed that Go6983 treatment led to decreased enrichment of dimethylation and trimethylation of H3K9 at the Prdm14 promoter but increased RNA polymerase Ⅱ binding affinity. Together, our results provide novel insights into the pivotal association between PKC inhibition-mediated self-renewal and epigenetic changes, which will help us better understand the regulatory network of stem cell pluripotency.

Chiral acidic molecularly imprinted polymer for enantio-separation of norepinephrine racemate.

We are looking into how well a copolymeric material made of poly (maleic acid-co-4-vinylpyridine) cross-linked with divinylbenzene can separate L-norepinephrine (L-NEP) from (±)-NEP. The initial step in this direction was the synthesis and subsequent analysis of L-NEP-maleimide chiral derivative. A 4-vinylpyridine/divinylbenzene combination was copolymerized with the resultant chiral maleimide. After heating the polymer materials in a high-alkaline environment to breakdown the connecting imide bonds, they were acidified in an HCl solution to eliminate the incorporated L-NEP species. Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope were used to examine the imprinted L-NEP-imprinted materials. The manufactured L-NEP-imprinted materials exhibited selectivity characteristics that were over 11 times greater for L-NEP than D-norepinephrine. The highest capacity observed in Langmuir adsorption studies was 170 mg/g at a pH of 7. After optical separation using a column technique, it was determined that the enantiomeric excess levels of D-norepinephrine and L-NEP in the first feeding and subsequent recovery solutions were 95% and 81%, respectively.