Fucosylation and galactosylation in N-glycans of bovine intestinal alkaline phosphatase and their role in its enzymatic activity.

Bovine intestinal alkaline phosphatase (biALP), a membrane-bound plasma metalloenzyme, maintains intestinal homeostasis, regulates duodenal surface pH, and protects against infections caused by pathogenic bacteria. The N-glycans of biALP regulate its enzymatic activity, protein folding, and thermostability, but their structures are not fully reported. In this study, the structures and quantities of the N-glycans of biALP were analyzed by liquid chromatography-electrospray ionization-high energy collision dissociation-tandem mass spectrometry. In total, 48 N-glycans were identified and quantified, comprising high-mannose [6 N-glycans, 33.1 % (sum of relative quantities of each N-glycan)], hybrid (6, 11.9 %), and complex (36, 55.0 %) structures [bi- (13, 26.1 %), tri- (16, 21.5 %), and tetra-antennary (7, 7.4 %)]. These included bisecting N-acetylglucosamine (33, 56.6 %), mono-to tri-fucosylation (32, 53.3 %), mono-to tri-α-galactosylation (16, 20.7 %), and mono-to tetra-ß-galactosylation (36, 58.5 %). No sialylation was identified. N-glycans with non-bisecting GlcNAc (9, 10.3 %), non-fucosylation (10, 13.6 %), non-α-galactosylation (26, 46.2 %), and non-ß-galactosylation (6, 8.4 %) were also identified. The activity (100 %) of biALP was reduced to 37.3 ± 0.2 % (by de-fucosylation), 32.7 ± 2.9 % (by de-α-galactosylation), and 0.2 ± 0.2 % (by de-ß-galactosylation), comparable to inhibition by 10-4 to 101 mM EDTA, a biALP inhibitor. These results indicate that fucosylated and galactosylated N-glycans, especially ß-galactosylation, affected the activity of biALP. This study is the first to identify 48 diverse N-glycan structures and quantities of bovine as well as human intestinal ALP and to demonstrate the importance of the role of fucosylation and galactosylation for maintaining the activity of biALP.

Low-Voltage Hydrogen Production via Hydrogen Peroxide Oxidation Facilitated by Oxo Ligand Axially Coordinated to Cobalt in Phthalocyanine Moiety.

A cobalt phthalocyanine having an electron-poor CoN4 (+δ) in its phthalocyanine moiety was presented as an electrocatalyst for hydrogen peroxide oxidation reaction (HPOR). We suggested that hydrogen peroxide as an electrolysis medium for hydrogen production and therefore as a hydrogen carrier, demonstrating that the electrocatalyst guaranteed high hydrogen production rate by hydrogen peroxide splitting. The electron deficiency of cobalt allows CoN4 to have the highly HPOR-active monovalent oxidation state and facilitates HPOR at small overpotentials range around the onset potential. The strong interaction between the electron-deficient cobalt and oxygen of peroxide adsorbates in Co─OOH- encourages an axially coordinated cobalt oxo complex (O═CoN4 ) to form, the O═CoN4 facilitating the HPOR efficiently at high overpotentials. Low-voltage oxygen evolution reaction guaranteeing low-voltage hydrogen production is successfully demonstrated in the presence of the metal-oxo complex having electron-deficient CoN4 . Hydrogen production by 391 mA cm-2 at 1 V and 870 mA cm-2 at 1.5 V is obtained. Also, the techno-economic benefit of hydrogen peroxide as a hydrogen carrier is evaluated by comparing hydrogen peroxide with other hydrogen carriers such as ammonia and liquid organic hydrogen carriers.

Fragmentation stability and retention time-shift obtained by LC-MS/MS to distinguish sialylated N-glycan linkage isomers in therapeutic glycoproteins.

Sialylated N-glycan isomers with α2-3 or α2-6 linkage(s) have distinctive roles in glycoproteins, but are difficult to distinguish. Wild-type (WT) and glycoengineered (mutant) therapeutic glycoproteins, cytotoxic T lymphocyte-associated antigen-4-immunoglobulin (CTLA4-Ig), were produced in Chinese hamster ovary cell lines; however, their linkage isomers have not been reported. In this study, N-glycans of CTLA4-Igs were released, labeled with procainamide, and analyzed by liquid chromatography-tandem mass spectrometry (MS/MS) to identify and quantify sialylated N-glycan linkage isomers. The linkage isomers were distinguished by comparison of 1) intensity of the N-acetylglucosamine ion to the sialic acid ion (Ln/Nn) using different fragmentation stability in MS/MS spectra and 2) retention time-shift for a selective m/z value in the extracted ion chromatogram. Each isomer was distinctively identified, and each quantity (>0.1%) was obtained relative to the total N-glycans (100%) for all observed ionization states. Twenty sialylated N-glycan isomers with only α2-3 linkage(s) in WT were identified, and each isomer's sum of quantities was 50.4%. Furthermore, 39 sialylated N-glycan isomers (58.8%) in mono- (3 N-glycans; 0.9%), bi- (18; 48.3%), tri- (14; 8.9%), and tetra- (4; 0.7%) antennary structures of mutant were obtained, which comprised mono- (15 N-glycans; 25.4%), di- (15; 28.4%), tri- (8; 4.8%), and tetra- (1; 0.2%) sialylation, respectively, with only α2-3 (10 N-glycans; 4.8%), both α2-3 and α2-6 (14; 18.4%), and only α2-6 (15; 35.6%) linkage(s). These results are consistent with those for α2-3 neuraminidase-treated N-glycans. This study generated a novel plot of Ln/Nn versus retention time to distinguish sialylated N-glycan linkage isomers in glycoprotein.

Establishment of TUBB3-mCherry knock-in human pluripotent stem cell line using CRISPR/Cas9 (SNUe003-A-4).

TUBB3 is a structural neuronal protein important for multiple neuronal functions including axonal guidance and maturation. This study aimed to generate a human pluripotent stem cell (hPSC) line with a TUBB3-mCherry reporter using CRISPR/SpCas9 nuclease. The stop codon in the last exon of TUBB3 was replaced with a T2A-mCherry cassette using CRISPR/SpCas9-mediated homologous recombination. The established TUBB3-mCherry knock-in cell line exhibited typical pluripotent characteristics. The mCherry reporter faithfully replicated the endogenous level of TUBB3 upon induction of neuronal differentiation. The reporter cell line could contribute to the investigation of neuronal differentiation, neuronal toxicity, and neuronal tracing.

Peptide-N-glycosidase F or A treatment and procainamide-labeling for identification and quantification of N-glycans in two types of mammalian glycoproteins using UPLC and LC-MS/MS.

BACKGROUND: N-glycans in glycoproteins can affect physicochemical properties of proteins; however, some reported N-glycan structures are inconsistent depending on the type of glycoprotein or the preparation methods. OBJECTIVE: To obtain consistent results for qualitative and quantitative analyses of N-glycans, N-glycans obtained by different preparation methods were compared for two types of mammalian glycoproteins. METHODS: N-glycans are released by peptide-N-glycosidase F (PF) or A (PA) from two model mammalian glycoproteins, bovine fetuin (with three glycosylation sites) and human IgG (with a single glycosylation site), and labeled with a fluorescent tag [2-aminobenzamide (AB) or procainamide (ProA)]. The structure and quantity of each N-glycan were determined using UPLC and LC-MS/MS. RESULTS: The 21 N-glycans in fetuin and another 21 N-glycans in IgG by either PF-ProA or PA-ProA were identified using LC-MS/MS. The N-glycans in fetuin (8-13 N-glycans were previously reported) and in IgG (19 N-glycans were previously reported), which could not be identified by using the widely used PF-AB, were all identified by using PF-ProA or PA-ProA. The quantities (%) of the N-glycans (>0.1 %) relative to the total amount of N-glycans (100 %) obtained by AB- and ProA-labeling using LC-MS/MS had a similar tendency. However, the absolute quantities (pmol) of the N-glycans estimated using UPLC and LC-MS/MS were more efficiently determined with ProA-labeling than with AB-labeling. Thus, PF-ProA or PA-ProA allows for more effective identification and quantification of N-glycans than PF-AB in glycoprotein, particularly bovine fetuin. This study is the first comparative analysis for the identification and relative and absolute quantification of N-glycans in glycoproteins with PF-ProA and PA-ProA using UPLC and LC-MS/MS.

Generation of αMHC-EGFP knock-in in human pluripotent stem cell line, SNUe003-A-3 using CRISPR/Cas9-based gene targeting.

The cardiac muscle-specific protein, α-myosin heavy chain (αMHC), is a major component of cardiac muscle filaments involved in cardiac muscle contraction. Here, we established an αMHC-enhanced fluorescent protein (EGFP) knock-in human pluripotent stem cell (hPSC) line by linking the EGFP gene to the C-terminal region of αMHC via a 2A non-joining peptide using CRISPR/Cas9 nuclease. The EGFP reporter precisely reflected the endogenous level of αMHC upon the induction of cardiac differentiation. This reporter cell line will be a valuable platform for cardiotoxicity tests, drug screening, and investigating the pathological mechanisms of cardiomyocytes.

Identification and quantification of sialylated and core-fucosylated N-glycans in human transferrin by UPLC and LC-MS/MS.

Sialylated and core-fucosylated N-glycans in human transferrin (HTF) are used as glycan biomarkers due to their increased or decreased characteristics in certain diseases. However, their absolute quantities remain unclear. In this study, N-glycans of HTF were identified by UPLC and LC-MS/MS using fluorescence tags [2-aminobenzamide (AB) and procainamide (ProA)] and columns [HILIC and anion exchange chromatography-HILIC (AXH)]. The structures of 14 (including five core-fucosylated) N-glycans in total comprising two non-, six mono-, four di-, and two tri-sialylated N-glycans were identified. The quantities (%) of each N-glycan relative to the total N-glycans (100%) were obtained. HILIC and AXH were better for peak identification and separability except for desialylation, respectively. Specifically, sialylated (in ProA-HILIC and ProA-AXH by UPLC or LC-MS/MS) and core-fucosylated (in AB-HILIC and ProA-AXH by UPLC) N-glycans were efficiently identified. Seven neuraminidase-treated (including three core-fucosylated) N-glycans were efficiently identified in ProA-AXH, even their poor separation. Additionally, ProA-AXH was more efficient for the estimation of the absolute quantities of N-glycans from the results of fluorescence intensity (by UPLC) and relative quantity (by LC-MS/MS). These results first demonstrate that ProA is useful for identifying and quantifying sialylated, core-fucosylated, and neuraminidase-treated desialylated N-glycans in HTF using AXH by UPLC and LC/MS.

Unidentified N-glycans by N-glycosidase A were Identified by Nglycosidase F under Denaturing Conditions in Plant Glycoprotein.

BACKGROUND: The identification of N-glycans in plant glycoproteins or plant-made pharmaceuticals is essential for understanding their structure, function, properties, immunogenicity, and allergenicity (induced by plant-specific core-fucosylation or xylosylation) in the applications of plant food, agriculture, and plant biotechnology. N-glycosidase A is widely used to release the Nglycans of plant glycoproteins because the core-fucosylated N-glycans of plant glycoproteins are hydrolyzed by N-glycosidase A but not by N-glycosidase F. However, the efficiency of Nglycosidase A activity in plant glycoproteins remains unclear. OBJECTIVE: The aim of the study was to elucidate the efficient use of N-glycosidases to identify and quantify the N-glycans of plant glycoproteins; it aimed at identification of released N-glycans by Nglycosidase F and assessment of their relative quantities with a focus on unidentified N-glycans by N-glycosidase A in plant glycoproteins, Phaseolus vulgaris lectin (PHA) and horseradish peroxidase (HRP). METHODS: Liquid chromatography-tandem mass spectrometry was used to analyze and compare the N-glycans of PHA and HRP treated with either N-glycosidase A or F under denaturing conditions. The relative quantities (%) of each N-glycan (>0.1%) to the total N-glycans (100%) were determined. RESULTS: N-glycosidase A and F released 9 identical N-glycans of PHA, but two additional corefucosylated N-glycans were released by only N-glycosidase A, as expected. By contrast, in HRP, 8 N-glycans comprising 6 core-fucosylated N-glycans, 1 xylosylated N-glycan, and 1 mannosylated N-glycan were released by N-glycosidase A. Moreover, 8 unexpected N-glycans comprising 1 corefucosylated N-glycan, 4 xylosylated N-glycans, and 3 mannosylated N-glycans were released by Nglycosidase F. Of these, 3 xylosylated and 2 mannosylated N-glycans were released by only Nglycansodase F. CONCLUSION: These results demonstrate that N-glycosidase A alone is insufficient to release the Nglycans of all plant glycoproteins, suggesting that to identify and quantify the released N-glycans of the plant glycoprotein HRP, both N-glycosidase A and F treatments are required.

Natural Products for Pancreatic Cancer Treatment: From Traditional Medicine to Modern Drug Discovery.

Pancreatic cancer, the seventh most lethal cancer around the world, is considered complicated cancer due to poor prognosis and difficulty in treatment. Despite all the conventional treatments, including surgical therapy and chemotherapy, the mortality rate is still high. Therefore, the possibility of using natural products for pancreatic cancer is increasing. In this study, 68 natural products that have anti-pancreatic cancer effects reported within five years were reviewed. The mechanisms of anti-cancer effects were divided into four types: apoptosis, anti-metastasis, anti-angiogenesis, and anti-resistance. Most of the studies were conducted for natural products that induce apoptosis in pancreatic cancer. Among them, plant extracts such as Eucalyptus microcorys account for the major portion. Some natural products, including Moringa, Coix seed, etc., showed multi-functional properties. Natural products could be beneficial candidates for treating pancreatic cancer.

Generation of Brachyury-mCherry knock-in reporter human pluripotent stem cell line (SNUe003-A-2) using CRISPR/CAS9 nuclease.

Brachyury is an embryonic nuclear transcription factor required for mesoderm formation and differentiation. Here, we introduced an mCherry reporter into the C-terminus of Brachyury in the human pluripotent stem cell line SNUhES3 using the CRISPR/Cas9 nuclease approach. Successful gene editing was verified by DNA sequencing. SNUhES3-Brachyury-mCherry cells expressed pluripotent stem cell markers, exhibited a normal karyotype, and could generate all three germ layers. This cell line expressed the red fluorescence protein mCherry upon the induction of mesoderm differentiation. This reporter cell line could be used to monitor mesodermal population enrichment during mesodermal differentiation.

My Privacy and Control Matter: Understanding Motivations for Using Untact Services.

This study's aim was to uncover psychological and social motives for using untact services and to explore the relationships between identified motivations and attitudinal and continuous behavioral intention variables. We conducted a survey with 328 untact service users, and used exploratory and confirmatory factor analysis to find underlying motivations. The findings suggest that users of untact services have four primary motives. Individuals use untact services to protect their personal information (privacy), to increase their control over business transactions (control), to enjoy the process itself (fun), and to avoid uncomfortable interactions with employees (interaction avoidance). In addition, identified motivations and attitudes toward as well as continuing intention to use the services were all positively related. Among the motivations, control showed the strongest relationship with both attitude and continuance intention.

Addition of an N-Terminal Poly-Glutamate Fusion Tag Improves Solubility and Production of Recombinant TAT-Cre Recombinase in Escherichia coli.

Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TATCre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TATCre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TATCre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.

Effects of Gender and Relationship Type on the Response to Artificial Intelligence.

Artificial intelligence (AI) has had a huge impact on our lives. In this study, we suggest that when people interact with AI, they regard the AI as a social actor and apply interpersonal relationship norms. This study employed a 2 × 2 between-subjects design to identify the effects of an AI's relationship type and gender on a human's response to an AI speaker (relationship type: friend vs. servant; gender: male vs. female). Findings show that the relationship type has a significant effect on warmth and pleasure but not on competence. The gender of the AI showed no significant effects on competence, warmth, or pleasure when controlling for the participants' gender. In addition, the results indicate that anthropomorphism fully mediated the relationship between both warmth and pleasure and the type of relationship with AI. Our findings suggest that AI is regarded as a social actor, and the characteristics of AI should be considered as they influence the response to AI.

Water Extract of Acori Graminei Rhizoma Attenuates Features of Rheumatoid Arthritis in DBA/1 Mice.

The dry rhizome of Acorus gramineus Solander, known as Acori Graminei Rhizoma, is used to treat dementia, stroke, eczema, and indigestion in traditional Chinese medicine, traditional Korean medicine, and traditional Japanese Kampo medicine. Previous studies have reported that Acori Graminei Rhizoma extract ameliorated cognitive impairment in Aß1-42 injected mice. However, the effect of Acori Graminei Rhizoma on type II collagen induced arthritis (CIA) has not been elucidated. Thus, we evaluated the water extract of Acori Graminei Rhizoma (WAG) in CIA mice models. Male DBA/1 mice were separated into five groups (NOR; n=10, CON; n=10, CIA + methotrexate (MTX); n=10, CIA + 100 mg/kg WAG; n=10, CIA + 500 mg/kg WAG; n=10). CIA was induced by injecting the mice with bovine type II collagen, after which the mice were treated with WAG and/or MTX. Hematological parameters and liver and kidney serum toxicity markers were analyzed. Further, serum levels of interleukin (IL)-6, TNF-α, and type II collagen IgG were analyzed via enzyme-linked immunosorbent assay (ELISA). Treatment with 500 mg/kg WAG decreased serum levels of IL-6, TNF-α, and collagen IgG in a CIA model. Moreover, WAG treatment decreased CIA-induced swelling of mouse hind legs, infiltration of inflammatory cells into the synovial membrane, and blood neutrophil levels. WAG administration did not influence hematological parameters or kidneys and liver toxicity markers. WAG may be used to treat arthritis by reducing the inflammation indicators. However, further experiments are required to determine how WAG affects inflammation mechanisms in vitro and in vivo.

Effect of Saururus chinensis leaves extract on type II collagen-induced arthritis mouse model.

BACKGROUND: Saururus chinensis leaves have been used as traditional medicine in Korea for pain, intoxication, edema, and furuncle. According to previous reports, these leaves exert renoprotective, neuroprotective, and antioxidant effects by attenuating inflammatory responses. However, the beneficial effect of Saururus chinensis leaves on arthritis has not been elucidated. Thus, we evaluated the water extract of Saururus chinensis leaves (SHW) using type II collagen-induced arthritis (CIA) mice models. METHODS: Quantitative analysis of major components from SHW was performed by HPLC. Arthritis was induced by injection of type II collagen. Each group was orally administered SHW (100 mg/kg and 500 mg/kg). Methotrexate (MTX) was used as a positive control. Serum levels of interleukin-6, TNF-alpha, and type II collagen IgG in the animal models were measured using ELISA. Histological features were observed by H&E staining. RESULTS: Quantitative analysis of SHW showed the contents as 56.4 ± 0.52 mg/g of miquelianin, 7.75 ± 0.08 mg/g of quercetin 3-O-(2"-O-ß -glucopyranosyl)-α-rhamnopyranoside, and 3.17 ± 0.02 mg/g of quercitrin. Treatment with 500 mg/kg SHW decreased the serum level of Interleukin-6 (IL-6), TNF-alpha, and collagen IgG in the CIA model. Moreover, SHW treatment diminished the swelling of hind limbs and monocyte infiltration in blood vessels in CIA animal models. The results indicate that SHW could decrease CIA-induced arthritis in vivo. CONCLUSIONS: The results indicate that SHW could be used to improving arthritis by reducing inflammatory factors (IL-6 and TNF-alpha). However, further experiments are required to determine how SHW influences signal transduction in animal models.

Inhibition of lactate dehydrogenase A suppresses inflammatory response in RAW 264.7 macrophages.

Lactate is an important metabolite in cellular metabolism and fluctuates in certain disease conditions including cancer and immune diseases. It was hypothesized that a decrease in lactate would modulate the inflammatory response elicited by lipopolysaccharides (LPS) in macrophages. When RAW 264.7 macrophages were treated with FX11, a specific lactate dehydrogenase (LDHA) inhibitor, the expression of the cytokines, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX­2) was downregulated due to reduced cellular lactate levels. Genetic suppression of LDHA by small interfering RNA (siRNA) downregulated the LPS­activated expression of interleukin (IL)­6, iNOS, and COX­2, and reduced the production of IL­6 and nitrites. Pharmacological and genetic suppression of LDHA inhibited the phosphorylation of p38 mitogen­activated protein kinase. Microarray gene expression profile demonstrated that the genes involved in cell proliferation and inflammation were mainly altered by siRNA­mediated LDHA suppression. Collectively, the present observations suggest that lactate may be an important metabolite and implicated in regulation of inflammatory response.

Differential regulation of MyD88- and TRIF-dependent signaling pathways of Toll-like receptors by cardamonin.

Toll-like receptors (TLRs) play a crucial role in the induction of innate immune response against bacterial and viral infections. TLRs induce downstream signaling via MyD88- and TRIF-dependent pathways. Cardamonin is a naturally occurring chalcone from Alpinia species exhibiting anti-inflammatory effects. However, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the role of cardamonin in TLR signaling pathways. Cardamonin inhibited NF-κB activation as well as COX-2 expression induced by TLR agonists. Cardamonin inhibited the activation of IRF3 and the expression of interferon-inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. Cardamonin also inhibited ligand-independent NF-κB activation overexpressed by MyD88, IKKß, or p65 and IRF3 activation overexpressed by TRIF, TBK1, or IRF3. However, cardamonin had no effect on TBK1 kinase activity in vitro. These results suggest that cardamonin modulates both the MyD88- and TRIF-dependent pathways of TLRs and represents a potentially new anti-inflammatory candidate.

Andrographolide suppresses TRIF-dependent signaling of toll-like receptors by targeting TBK1.

Toll-like receptors (TLRs) play a crucial role in danger recognition and induction of innate immune response against bacterial and viral infections. The TLR adaptor molecule, toll-interleukin-1 receptor domain-containing adapter inducing interferon-ß (TRIF), facilitates TLR3 and TLR4 signaling, leading to the activation of the transcription factor, NF-κB and interferon regulatory factor 3 (IRF3). Andrographolide, the active component of Andrographis paniculata, exerts anti-inflammatory effects; however, the principal molecular mechanisms remain unclear. The objective of this study was to investigate the role of andrographolide in TLR signaling pathways. Andrographolide suppressed NF-κB activation as well as COX-2 expression induced by TLR3 or TLR4 agonists. Andrographolide also suppressed the activation of IRF3 and the expression of interferon inducible protein-10 (IP-10) induced by TLR3 or TLR4 agonists. Andrographolide attenuated ligand-independent activation of IRF3 following overexpression of TRIF, TBK1, or IRF3. Furthermore, andrographolide inhibited TBK1 kinase activity in vitro. These results indicate that andrographolide modulates the TRIF-dependent pathway of TLRs by targeting TBK1 and represents a potential new anti-inflammatory candidate.

Suppression of Toll-Like Receptor 4 Dimerization by 1-[5-Methoxy-2-(2-nitrovinyl)phenyl]pyrrolidine.

Toll-like receptor 4 (TLR4) recognizes lipopolysaccharide (LPS) and triggers the activation of myeloid differention factor 88 (MyD88) and the Toll/interleukin-1 receptor domain-containing adapter, inducing interferon-ß (TRIF)-dependent major downstream signaling pathways. To evaluate the therapeutic potential of 1-[5-methoxy-2-(2-nitrovinyl)phenyl]pyrrolidine (MNP), previously synthesized in our laboratory, its effect on signal transduction via the TLR signaling pathways was examined. Here, we investigated whether MNP modulates the TLR4 signaling pathways and which anti-inflammatory target in TLR4 signaling is regulated by MNP. MNP inhibited the activation of nuclear factor-κB (NF-κB) induced by LPS (TLR4 agonist), and it also inhibited the expression of cyclooxygenase-2 and inducible nitric oxide synthase. MNP inhibited LPS-induced NF-κB activation by targeting TLR4 dimerization in addition to IKKß. These results suggest that MNP can modulate the TLR4 signaling pathway at the receptor level to decrease inflammatory gene expression.

Suppression of TLRs signaling pathways by 1-[5-methoxy-2-(2-nitrovinyl)phenyl]pyrrolidine.

Toll-like receptors (TLRs) play significant roles in recognizing the pathogen-associated molecular patterns that induce innate immunity, and subsequently, acquired immunity. In general, TLRs have two downstream signaling pathways, the myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter-inducing interferon-ß (TRIF)-dependent pathways, which lead to the activation of nuclear factor-kappa B (NF-κB) and interferon regulatory factor 3 (IRF3). 1-[5-methoxy-2-(2-nitrovinyl)phenyl]pyrrolidine (MNP) has been previously synthesized in our laboratory. To evaluate the therapeutic potential of MNP, its effect on signal transduction via the TLR signaling pathways was examined. MNP was shown to inhibit the activation of NF-κB and IRF3 induced by TLR agonists, as well as to inhibit the expression of cyclooxygenase-2, inducible nitric oxide synthase, and interferon inducible protein-10. MNP also inhibited the activation of NF-κB and IRF3 induced by the overexpression of downstream signaling components of the MyD88- or TRIF-dependent signaling pathways. These results suggest that MNP can modulate MyD88- and TRIF-dependent signaling pathways of TLRs, leading to decreased inflammatory gene expression.