Design,synthesis, and activity evaluation of novel erythropoietin mimetic peptides

The approval of the erythropoietin (EPO) mimetic peptide drug peginesatide in 2012 was a breakthrough for the treatment of secondary anemia. However, due to severe allergic reactions, peginesatide was recalled a year later. In this study, 12 novel peptides were designed and synthesized by substituting specific amino acids of the monomeric peptide in peginesatide, with the aim of obtaining new EPO mimetic peptides with higher activities and lower side effects than the parent compound. Their cell proliferation activities were evaluated, and the structure-activity relationships were analyzed. Five compounds had equal cell proliferation activity to the control peptide. Among them, one compound showed a higher in vivo activity than the control peptide, with no obvious side effects.     

Fibrinolytic and anticoagulative activities from the earthworm Eisenia foetida

Biologically active glycolipoprotein complex (G-90) isolated from whole earthworm tissue extract shows anticoagulative and fibrinolytic activities. We isolated two tyrosine like serine peptidases with molecular masses of 34 kDa (P I) and 23 kDa (P II), respectively. P I peptidase is autocatalytically degraded to P II. Both peptidases exhibit fibrinolytic and anticoagulative activities. The activity of P I is much higher. P I in concentration of 10⁵ ng ml⁻¹ of plasma shortened the physiological time of fibrin clot lysis by 54% and completely inhibited blood clotting at a concentration of 10³ ng ml⁻¹ of venous blood.     

The 1,2,4-triazole as a scaffold for the design of ghrelin receptor ligands: development of JMV 2959, a potent antagonist

Ghrelin is a 28-residue peptide acylated with an n-octanoyl group on the Ser 3 residue, predominantly produced by the stomach. Ghrelin displays strong growth hormone (GH) releasing activity, which is mediated by the activation of the so-called GH secretagogue receptor type 1a (GHS-R1a). Given the wide spectrum of biological activities of Ghrelin in neuroendocrine and metabolic pathways, many research groups, including our group, developed synthetic peptide, and nonpeptide GHS-R1a ligands, acting as agonists, partial agonists, antagonists, or inverse agonists. In this highlight article, we will focus on the discovery of a GHS-R1a antagonist compound, JMV 2959, which has been extensively studied in different in vitro and in vivo models. We will first describe the peptidomimetic approach that led us to discover this compound. Then we will review the results obtained with this compound in different studies in the fields of food intake and obesity, addictive behaviors, hyperactivity and retinopathy.     

Synthesis and some pharmacological properties of [I-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-8-lysine-vasopressin

The title compound, [1-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-8-lysine-vasopressin (X), was synthesized by condensation of Pro-Lys(Boc)-Gly-NH₂ with the cyclic peptide [1-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-pressinoic acid. X has no oxytocic, avian vasodepressor, pressor, or antipressor activities, but is a weak inhibitor of the responses to oxytocin in the oxytocic and avian vasodepressor assays. Its pharmacological properties are qualitatively identical to those of the corresponding analog of oxytocin, although it is a less potent antagonist than the latter compound.     

Acid and heat stability of the anticoagulative activity of an onion extract

An onion extract possessed anticoagulative activity apparently by inhibiting thrombin, and it was dependent upon the concentration of onion extract added. Boiling the onion extract at 100 degrees C for 30 min made no difference to its anticoagulative activity compared to that of fresh onion. The anticoagulative activity of the onion extract was also retained after an acid treatment by incubating at pH 2.0 for 4 hrs. However, dialyis of the extract substantially eliminated the anticoagulative activity. Therefore, the anticoagulant in the onion extract seems to have been a heat- and acid-stable substance of low molecular weight.     

Cardamonin protects septic mice from acute lung injury by preventing endothelial barrier dysfunction

Cardamonin, a flavone compound isolated from Alpinia katsumadai Heyata seeds, has been reported to possess anti-inflammatory and anticoagulative activities, and it might be beneficial for management of sepsis. This study was conducted to examine the protective effects of cardamonin on experimental sepsis and resultant acute lung injury (ALI). Cardamonin (30 and 100 mg/kg) significantly elevated the survival rate of septic mice, alleviated ALI and lung microvascular leak, and lowered the serum levels of proinflammatory cytokines TNF-α, IL-1β, and IL-6. In vitro, it (25 and 50 μM) concentration dependently inhibited endothelium permeability and downregulated phosphorylation of P38 in rat lung microvascular endothelial cells induced by lipopolysaccharide (LPS). P38 inhibitor inhibited the endothelium permeability. In RAW 264.7 macrophage cells, cardamonin also showed selective inhibition of P38 phosphorylation induced by LPS. These results indicate that cardamonin can protect septic mice from ALI by preventing endothelium barrier dysfunction via selectively inhibiting P38 activation.     

Synthesis and some pharmacological properties of [I-β-mercaptopropionic acid, 2-(3,5-dibromo- -tyrosine)]-8-lysine-vasopressin

The title compound, [1-β-mercaptopropionic acid, 2-(3,5-dibromo- -tyrosine)]-8-lysine-vasopressin (X), was synthesized by condensation of Pro-Lys(Boc)-Gly-NH₂ with the cyclic peptide [1-β-mercaptopropionic acid, 2-(3,5-dibromo- -tyrosine)]-pressinoic acid. X has no oxytocic, avian vasodepressor, pressor, or antipressor activities, but is a weak inhibitor of the responses to oxytocin in the oxytocic and avian vasodepressor assays. Its pharmacological properties are qualitatively identical to those of the corresponding analog of oxytocin, although it is a less potent antagonist than the latter compound.     

Design,synthesis, and biological evaluation of selective and potent Carbazole-based butyrylcholinesterase inhibitors

Alzheimer’s disease (AD) is the most common form of dementia. Inhibition of BChE might be a useful therapeutic target for AD. A new series of Carbazole-Benzyl Pyridine derivatives were designed synthesized and evaluated as butyrylcholinesterase (BChE) inhibitors. In vitro assay revealed that all of the derivatives had selective and potent anti- BChE activities. 3-((9H-Carbazol-9-yl)methyl)-1-(4-chlorobenzyl)pyridin-1-ium chloride (compound 8f) had the most potent anti-BChE activity (IC₅₀ value?=?0.073?μM), the highest BChE selectivity and mixed-type inhibition. Docking study revealed that 8f interacted with the peripheral site, the choline binding site, catalytic site and the acyl pocket of BChE. Physicochemical properties were accurate to Lipinski's rule. In addition, compound 8f demonstrated neuroprotective activity at 10?µM. This compound could also inhibit AChE-induced and self-induced Aβ peptide aggregation at concentration of 100?µM and 10?µM respectively. The in-vivo study showed that compound 8f in 10?mg/kg increased the time spent in target quadrant in the probe day and decreased mean training period scape latency in rats. All results suggest that new sets of potent selective inhibitors of BChE have a therapeutic potential for the treatment of AD.     

Design, synthesis, and studies of small molecule STAT3 inhibitors

A series of small molecule STAT3 inhibitors originally derived from our lead compound STA 21 were synthesized and evaluated. The most potent compound in this series, compound 1, exhibited the same anti-proliferative activities as STA 21 against prostate cancer cell lines that express constitutively active STAT3. Molecular docking showed compound 1 bound to the STAT3beta SH2 domain in a similar manner as STA 21.     

A novel bovine lactoferrin peptide, FKCRRWQWRM, suppresses Candida cell growth and activates neutrophils.

To identify potent new antifungal agents, the Candida cell growth inhibitory activities of six lactoferrin (Lf) peptides consisting of 6-25 amino acid residues (peptide 1, FKCRRWQWRMKKLGAPSITCVRRAF lactoferricin B; peptide 2, FKCRRWQWRM; peptide 2', FKARRWQWRM; peptide 3, GAPSITCVRRAF; peptide 4, RRWQWR; and peptide 5, RWQWRM) were examined. Of these, peptide 2 strongly suppressed the multiplication of Candida cells, but other peptides showed only weak activities. In two strains of C. albicans, the minimum inhibitory concentration 100 of peptide 2 (17.3+/-2.2 microM and 17.5+/-2.4 microM) was close to that of miconazole (13.0+/-1.7 microM and 13.1+/-1.6 microM) but markedly different from that of amphotericin B (0.52+/-0.09 microM and 0.56+/-0.11 microM). The suppression of Candida cell growth was additively increased by a combination of peptide 2 with amphotericin B and miconazole. Peptides 1, 3, 4 and 5 and Lf suppressed iron uptake by Candida cells, inversely correlated with their Candida cell growth inhibition activities. However, iron uptake was not inhibited by peptide 2. In addition, peptide 2 upregulated Candida cell killing activity of polymorphonuclear leukocytes (PMN) increasing their superoxide generation, protein kinase C activity, p38 MAPK activity and the expression of p47phox. These results indicated that the main antimicrobial activity of the Lf peptides is dependent on the N-terminal half of Lf and that the PMN upregulatory activity of peptide 2 and additive function of peptide 2 with antifungal drugs are useful for prophylaxis and control of candidiasis.     

New benzyl pyridinium derivatives bearing 2,4-dioxochroman moiety as potent agents for treatment of Alzheimer’s disease: Design,synthesis, biological evaluation,and docking study

A new series of benzyl pyridinium-2,4-dioxochroman derivatives 7a-o was synthesized and evaluated as new anti-Alzheimer agents. Among the synthesized compounds, the compounds 7f and 7i exhibited the most potent anti-AChE and anti-BuChE activities, respectively. The kinetic study of the compound 7f revealed that this compound inhibited AChE in a mixed-type inhibition mode. Furthermore, the docking study of the compounds 7f and 7i showed that these compounds bound to both the catalytic site (CS) and peripheral anionic site (PAS) of AChE and BuChE, respectively. The compound 7f also exhibited a greater self-induced Aβ peptide aggregation inhibitory activity in compare to donepezil. Furthermore, the neuroprotective activity of this compound at 20 μM was comparable to that of the standard neuroprotective agent (quercetin).     

Antimicrobial effects of H4-(86-100), histogranin and related compounds--possible involvement of DNA gyrase

Histone-derived antimicrobial peptides have been identified in various organisms from plants to humans. The rat histone H4 mRNA variants, H4-v.1 and rat histogranin (HNr) mRNAs, were recently reported to be involved in the synthesis of H4-(86-100) and its related peptide HNr, respectively. Herein, the two peptides were investigated for putative antimicrobial activity and found to inhibit growth of gram-negative (Escherichia coli, Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis, Staphylococcus aureus) bacteria. Their inhibitory potencies in E. coli (LD(50): 3.48 and 4.34 microg x mL(-1)) are comparable to that of the antimicrobial peptide LL-37 (LD(50): 4.10 microg x mL(-1)). The antimicrobial activities of H4-(86-100) and HNr depend upon the integrity of the molecules, as precursors [H4-(84-102), pro-HNr] and fragments [bovine histogranin (HNb)-(1-13), HNb-(3-13), H4-(89-102) or OGP] are at least five times less potent than the parent peptides. Among various HN-like compounds, cyclo-(-Gly-pCl-Phe-Tyr-D-Arg) (compound 3) and N-5-guanidino pentanamide-(2R)-yl-2-N-(p-hydroxyphenylacetyl)-4-(p-chlorobenzoyl)-phenylene diamine (compound 8) display antimicrobial activities comparable to that of HNr. Interestingly, the antimicrobial activities of H4-(86-100), HNr and compound 3, like those of quinolone antibiotics acting as DNA gyrase poisons, are potentiated by ATP (1 mM) and coumermycin A1 (a DNA gyrase-linked ATPase inhibitor) and blocked by 2,4-dinitrophenol (DNP, an uncoupler of oxidative phosphorylation) and fluoroacetic acid (a metabolic poison). Finally, in vitro experiments indicate that H4-(86-100), HNr, compound 3 and compound 8, but not HNb-(1-13) or HNb-(3-13), inhibit DNA gyrase-mediated supercoiling of pBR322 DNA. These data indicate that the naturally occurring H4-(86-100) and HNr display antimicrobial effects that involve a modulation of ATP-dependent DNA gyrase.     

Isolation and characterization of free radical scavenging activities peptides derived from casein

A peptide having the strong free radical scavenging activities was separated from casein protein hydrolysate by chromatographic analyses such as ion-exchange and gel filtration. SP-II fraction obtained by SP-Sephadex C-25 chromatography showed the most potent superoxide anion scavenging activity (SOSA), and it was further separated into a peptide using an octadecylsilano-high performance liquid chromatography. The amino acid sequence of the peptide was Tyr-Phe-Tyr-Pro-Glu-Leu (YFYPEL). The concentration of the test compound required to reduce the produced superoxide anion to one-half (IC(50)) value for SOSA was 79.2 microM using tetrazolium salt 3'-{1-[(phenylamino)-carbonyl]-3,4-tetrazolium}-bis(4-methoxy-6-nitro)benzenesulfonic acid hydrate method. The IC50 value for the 1,1-diphenyl-2-picrylhydrazyl radical and hydroxyl radical scavenging activities were 98 and 251 microM, respectively, based on the electron spin resonance method. We characterized SOSA of the C-terminal sequence using EL, PEL, YPEL, and FYPEL. The activities preferred sequences were EL>YFYPEL>FYPEL>YPEL>PEL, suggesting that the Glu-Leu sequence is important for the activity.     

Discovery and development of substituted tyrosine derivatives as Bcl-2/Mcl-1 inhibitors

Anti-apoptotic Bcl-2 family proteins are vital for cancer cells to escape apoptosis, which make them attractive targets for cancer therapy. Recently, a lead compound 1 was found to modestly inhibit the binding of BH3 peptide to Bcl-2 protein with a K_i value of 5.2?µM. Based on this, a series of substituted tyrosine derivatives were developed and tested for their binding affinities to Bcl-2 protein. Results indicated that these compounds exhibited potent binding affinities to Bcl-2 and Mcl-1 protein but not to Bcl-X_L protein. Promisingly, compound 6i inhibited the binding of BH3 peptide to Bcl-2 and Mcl-1 protein with a K_i value of 450 and 190?nM respectively, and showed obvious anti-proliferative activities against tested cancer cells.     

Synthesis and biological activity of nociceptin/orphanin FQ analogues substituted in position 7 or 11 with Calpha,alpha-dialkylated amino acids

Previous structure-activity and NMR studies on nociceptin/orphanin FQ (N/OFQ) demonstrated that Aib substitution of Ala(7) and/or Ala(11) increases the peptide potency through an alpha helix structure induction mechanism. On these bases we synthesised and evaluated pharmacologically in the mouse vas deferens assay a series of N/OFQ-NH(2) analogues substituted in position 7 and 11 with Calpha,alpha-disubstituted cyclic, linear and branched amino acids. None of the 20 novel N/OFQ analogues produced better results than [Aib(7)]N/OFQ-NH(2). Thus, this substitution was combined with other chemical modifications known to modulate peptide potency and/or efficacy generating compound 21 [Nphe(1)Aib(7)Arg(14)Lys(15)]N/OFQ-NH(2) (coded as UFP-111), compound 22 [(pF)Phe(4)Aib(7)Arg(14)Lys(15)]N/OFQ-NH(2) (UFP-112) and compound 23 [Phe(1)Psi(CH(2)-NH)Gly(2)(pF)Phe(4)Aib(7)Arg(14)Lys(15)]N/OFQ-NH(2) (UFP-113). These novel peptides behaved as highly potent NOP receptor ligands showing full (UFP-112) and partial (UFP-113) agonist and pure antagonist (UFP-111) activities in a series of in vitro functional assays performed on pharmacological preparations expressing native as well as recombinant NOP receptors.     

(3S)-N-(L-Aminoacyl)-1,2,3,4-tetrahydroisoquinolines, a class of novel antithrombotic agents: synthesis, bioassay, 3D QSAR, and ADME analysis

To increase antithrombotic activity, 3S-tetrahydroisoquinoline-3-carboxylic acid (1) was modified with natural amino acids to form 19 novel dipeptide analogs, 3S-tetrahydroisoquinoline-3-carboxyamino acids (5a-s), targeting the intestinal peptide transport system. In vitro assay of 5a-s indicated that their potencies for inhibiting adenosine diphosphate (ADP), arachidonic acid (AA), platelet-activating factor (PAF), and thrombin (TH)-induced platelet aggregations were higher than that of 1. Additionally, in vivo assay of 5a-s indicated that their potencies for inhibiting thrombogenesis in rats were also higher than that of 1. Among the candidates, 5h with Ser attachment showed the most impressive features for further development. According to molecular field analysis based Cerius(2) QSAR module, two equations (r, 0.961 and 0.988) correlating the structures with both in vitro and in vivo activities of 5a-s were established. ADMET calculations predict higher intestinal absorption for compounds 5a-s. Further investigation with 5h as a lead compound is underway.     

Synthesis, in vitro assay, and molecular modeling of new piperidine derivatives having dual inhibitory potency against acetylcholinesterase and Abeta1-42 aggregation for Alzheimer's disease therapeutics

With the goal of developing Alzheimer's disease therapeutics, we have designed and synthesized new piperidine derivatives having dual action of acetylcholinesterase (AChE) and beta-amyloid peptide (Abeta) aggregation inhibition. For binding with the catalytic site of AChE, an ester with aromatic group was designed, and for the peripheral site, another aromatic group was considered. And for intercalating amyloid-beta oligomerization, long and linear conformation with a lipophilic group was considered. The synthetic methods employed for the structure with dual action depended on alcohols with an aromatic ring and the substituted benzoic acids, which are esterificated in the last step of the synthetic pathway. We screened these new derivatives through inhibition tests of acetylcholinesterase, butyrylcholinesterase (BChE), and Abeta(1-42) peptide aggregation, AChE-induced Abeta(1-42) aggregation. Our results displayed that compound 12 showed the best inhibitory potency and selectivity of AChE, and 29 showed the highest selectivity of BChE inhibition. Compounds 15 and 12 had inhibitory activities against Abeta(1-42) aggregation and AChE-induced Abeta aggregation. In the docking model, we confirmed that 4-chlorobenzene of 12 plays the parallel pi-pi stacking against the indole ring of Trp84 in the bottom gorge of AChE. Because the benzyhydryl moiety of 12 covered the peripheral site of AChE in a funnel-like shape, 12 showed good inhibitory potency against AChE and could inhibit AChE-induced Abeta(1-42) peptide aggregation.     

Design,synthesis, and biological evaluation of novel aminopyrimidinylisoindolines as AXL kinase inhibitors

A novel series of aminopyrimidinylisoindoline derivatives 1a-w having an aminopyrimidine scaffold as a hinge region binding motif were designed and synthesized. Among them, six compounds showed potent inhibitory activities against AXL kinase with IC₅₀ values of submicromolar range. Especially, compound 1u possessing (4-acetylpiperazin-1-yl)phenyl moiety exhibited extremely excellent efficacy (IC₅₀?=?<0.00050?μM). Their in vitro antiproliferative activities were tested over five cancer cell lines. Most compounds showed good antiproliferative activities against HeLa cell line. The kinase panel profiling of 50 different kinases and the selected inhibitory activities for the representative compound 1u were carried out. The compound 1u exhibited excellent inhibitory activities (IC₅₀?=?<0.00050, 0.025, and 0.050?μM for AXL, MER, and TYRO3, respectively) against TAM family, together with potent antiproliferative activity against MV4-11 cell line (GI₅₀?=?0.10?μM) related to acute myeloid leukemia (AML).     

Solid phase synthesis and biological activities of [Arg8]-vasopressin methylenedithioether.

Solid phase synthesis of [Arg8]-vasopressin methylenedithioether, an analog of vasopressin which contains an extra methylene group between the two sulfur atoms of Cys1 and Cys6, is described. Methylene insertion occurred easily when the thiol free peptide on a solid support was treated with tetrabutylammonium fluoride in dichloromethane at room temperature for 3 h. The uterotonic in vitro, pressor, and antidiuretic activities of the compound were reduced in comparison to [Arg8]-vasopressin by one order of magnitude.