Activation of M1 muscarinic acetylcholine receptors by proline-rich oligopeptide 7a (

Background: The bioactive peptides derived from snake venoms of the Viperidae family species have been promising as therapeutic candidates for neuroprotection due to their ability to prevent neuronal cell loss, injury, and death. Therefore, this study aimed to evaluate the cytoprotective effects of a synthetic proline-rich oligopeptide 7a (PRO-7a; <EDGPIPP) from Bothrops jararaca snake, on oxidative stress-induced toxicity in neuronal PC12 cells and astrocyte-like C6 cells. Methods: Both cells were pre-treated for four hours with different concentrations of PRO-7a, submitted to H2O2-induced damage for 20 h, and then the oxidative stress markers were analyzed. Also, two independent neuroprotective mechanisms were investigated: a) L-arginine metabolite generation via argininosuccinate synthetase (AsS) activity regulation to produce agmatine or polyamines with neuroprotective properties; b) M1 mAChR receptor subtype activation pathway to reduce oxidative stress and neuron injury. Results: PRO-7a was not cytoprotective in C6 cells, but potentiated the H2O2-induced damage to cell integrity at a concentration lower than 0.38 μM. However, PRO-7a at 1.56 µM, on the other hand, modified H2O2-induced toxicity in PC12 cells by restoring cell integrity, mitochondrial metabolism, ROS generation, and arginase indirect activity. The α-Methyl-DL-aspartic acid (MDLA) and L-NΩ-Nitroarginine methyl ester (L-Name), specific inhibitors of AsS and nitric oxide synthase (NOS), which catalyzes the synthesis of polyamines and NO from L-arginine, did not suppress PRO-7a-mediated cytoprotection against oxidative stress. It suggested that its mechanism is independent of the production of L-arginine metabolites with neuroprotective properties by increased AsS activity. On the other hand, the neuroprotective effect of PRO-7a was blocked in the presence of dicyclomine hydrochloride (DCH), an M1 mAChR antagonist. Conclusions: For the first time, this work provides evidence that PRO-7a-induced neuroprotection seems to be mediated through M1 mAChR activation in PC12 cells, which reduces oxidative stress independently of AsS activity and L-arginine bioavailability.(AU)

Enzyme-instructed hybrid nanogel/nanofiber oligopeptide hydrogel for localized protein delivery

Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery, which has merits of biocompatibility, biodegradability and mild gelation conditions. However, its application for protein delivery is greatly limited by inevitable degradation of enzyme on the encapsulated proteins leading to loss of protein activity. Moreover, for the intracellularly acted proteins, cell membrane as a primary barrier hinders the transmembrane delivery of proteins. The internalized proteins also suffer from acidic and enzymatic degradation in endosomes and lysosomes. We herein develop a protease-manipulated hybrid nanogel/nanofiber hydrogel for localized delivery of intracellularly acted proteins. The embedded polymeric nanogels (CytoC/aNGs) preserve activity of cytochrome

Antiviral mechanism study of sulfated polysaccharidesf / Монголын Анагаах Ухаан

Background@#Sulfated polysaccharides have specific antiviral activities, which biological mechanism is assumed to the electrostatic interaction between (+)-charged virus surface glycoproteins and (-)-charged sulfate groups. @*Objective@#For the elucidation of the mechanism, several oligopeptides referenced by the sequence of Human Immunodeficiency Virus glycoprotein 120 (HIV gp120) and hemagglutinin (HA) of influenza A and B were synthesized by a peptide synthesizer and the interaction with structurally distinct sulfated polysaccharides such as curdlan sulfate and dextran sulfate was analyzed by SPR. @*Method@#In this study, six oligopeptides were synthesized from the sequence of the V3 loop, C-terminus, and CD4 binding domain in the HIV gp120. Oligopeptide A from the V3 loop comprises 20 amino acids with seven positively charged lysine and arginine in the sequence. The basic amino acids were relatively dispersed along the sequence compared with that of oligopeptide B. Likewise, oligopeptide B from the C–terminus comprises seven lysine and arginine, also oligopeptide of Influenza A/Yamagata HA and Influenza A/Brisbane HA comprises 23 amino acids with eight positively charged lysine and arginine in the sequence. Oligopeptide C from the CD4 binding domain and Influenza B /Hong Kong from the HA comprises one lysine and next to the biotin. The biotinylated peptides were synthesized by a microwave assisted solid phase peptide synthesizer using Fmoc protected amino acids. The peptides were purified by RP-HPLC and identified the structure by using MALDI TOF MS.@*Result@#Peptides A and B from HIV gp120 were found to have interacted strongly with dextran and curdlan sulfates, however, the peptide C without positively charged amino acids showed no interaction. These results suggest that the interaction was due to the electrostatic interaction between negatively charged sulfate groups and positively charged amino groups of the peptides. The results of influenza HAs, influenza A (Yamagata and Brisbane) and B (Hong Kong) viruses, are also presented.@*Conclusion@#Curdlan and dextran sulfates were found to increase the interaction with increasing the molecular weights and degree of sulfation (DS), which were found to be important factors for the antiviral activity of sulfated polysaccharides. Based on the above, suggesting the antivirus mechanism of sulfated polysaccharides to be the electrostatic interaction of negatively charged sulfated polysaccharides and virus surface glycoprotein at the positively charged amino acid regions.

Protective Effect of Oligopeptide FLPNF on Dexamethasone-Induced Apoptosis of Islet Cells / 中国医科大学学报

Objective To investigate the protective effect of FLPNF and the improvement of glucose-stimulated insulin secretion against dexamethasone-induced apoptosis of islet cells. Methods INS-1 cells were treated with oligopeptide FLPNF and dexamethasone, either separately or in combination. Proliferation of INS-1 cells in each group was assessed with CCK-8 assay and the insulin secretion stimulated by glucose was detected by ELISA. The apoptotic condition of the cells was observed and assessed with TUNEL and the apoptosis rate of each group was detected using flow cytometry. The expression of major target protein molecules related to apoptosis and Glut2 was detected by Western blotting analysis. Results Dexamethasone inhibited the growth of INS-1 cells in the group treated with dexamethasone. Cell damage was obvious with observable nuclear shrinkage and nuclear rupture. In addition, apoptosis rate was found to be 40.6％±2.4％. The expression of the apoptosis-related protein Bcl-2 and Glut2 was significantly reduced, whereas that of Bax and caspase-3 was significantly increased. After the combined treatment of oligopeptide FLPNF and dexamethasone, the results were reversed, and the apoptosis rate declined to 27.2％±2.0％ (P ＜ 0.001), cell morphology was improved, and the expression of apoptosis-related protein molecules of islet cells and protein Glut2 was significantly improved. Conclusion FLPNF has the ability of protecting islet cells from dexamethasone-induced apoptosis and improving the glucose-stimulated insulin secretion of islet cells.

Chinese materia medica-A natural bioactive oligopeptides bank / 中草药

Oligopeptides are simple in composition, high in safety index and good in drug preparation, which are important components of biomedicine. However, due to the limitation of oligopeptide drug design theory and discovery pathways which are far less than other structural drugs, obtaining new bioactive oligopeptides is a hot and difficult topic in this field. As a natural oligopeptide library, Chinese materia medica (CMM) contains a large number of active oligopeptides. Oligopeptides of CMM have vital biological activities such as neuroprotection activity, liver protection activity, antitumor, anticoagulation, anti-oxidation, immunity enhancement, etc. In this paper, the sequence and biological activity of active oligopeptides discovered by scholars at home and abroad in the past 10 years were reviewed, and the relationship between active oligopeptides and classification of CMM was explored. It is preliminarily suggested that CMM such as tonifying deficiency drugs and promoting blood circulation and removing blood stasis are the sources of natural oligopeptides. There are many research results easy to be successful in the research and development of new oligopeptide drugs, which provides directions and ideas for the development of new active oligopeptide drugs.

Fermentation of sheep bone enzymatic hydrolysates by Lactobacillus plantarum / 生物工程学报

In order to improve the nutritional value and bio-availability of sheep bone enzymatic hydrolysates, we tried to ferment the hydrolysates with lactic acid bacteria (LAB) to enhance free Ca²⁺, to generate oligopeptide and antioxidative activity. First, we isolated 7 LAB strains from commercial starters and selected Lactobacillus plantarum as the starter for its highest protease-producing ability. The content of released Ca²⁺ was evaluated when the fermenting conditions were optimized by the method of responsive surface design. When supplemented with 1% maltose and inoculated 4% L. plantarum, at initial pH 5.5 and 37 ℃ for 14 h, Ca²⁺ content in the hydrolysates increased significantly (P<0.05), as well as the generation oligopeptide (P<0.01), and the content of hydroxyproline (P<0.01). The count of L. plantarum in the fermented hydrolysates reached to 94.6×10⁸ CFU/mL. L. plantarum fermentation significantly enhanced the ability to scavenge free radicals DPPH, ·OH and O₂⁻· (P<0.01, P<0.05). Therefore, fermenting sheep bone hydrolysates by L. plantarum can increase free Ca²⁺, oligopeptide and antioxidative ability.

Cyclized Oligopeptide Targeting LRP5/6-DKK1 Interaction Reduces the Growth of Tumor Burden in a Multiple Myeloma Mouse Model

PURPOSE: Dickkopf 1 (DKK1) has been extensively investigated in mouse models of multiple myeloma, which results in osteolytic bone lesions. Elevated DKK1 levels in bone marrow plasma and serum inhibit the differentiation of osteoblast precursors. Present pharmaceutical approaches to target bone lesions are limited to antiresorptive agents. In this study, we developed a cyclized oligopeptide against DKK1-low density lipoprotein receptor-related protein (LRP) 5/6 interaction and tested the effects of the oligopeptide on tumor burden. MATERIALS AND METHODS: A cyclized oligopeptide based on DKK1-LRP5/6 interactions was synthesized chemically, and its nuclear magnetic resonance structure was assessed. Luciferase reporter assay and mRNA expressions of osteoblast markers were evaluated after oligopeptide treatment. MOPC315.BM.Luc cells were injected into the tail vein of mice, after which cyclized oligopeptide was delivered subcutaneously 6 days a week for 4 weeks. RESULTS: The cyclized oligopeptide containing NXI motif bound to the E1 domain of LRP5/6 effectively on surface plasmon resonance analysis. It abrogated the Wnt-β-catenin signaling inhibited by DKK1, but not by sclerostin, dose dependently. RT-PCR and alkaline phosphatase staining showed increased expressions of osteoblast markers according to the treatment concentrations. Bioluminescence images showed that the treatment of cyclized oligopeptide reduced tumor burden more in oligopeptide treated group than in the vehicle group. CONCLUSION: The cyclized oligopeptide reported here may be another option for the treatment of tumor burden in multiple myeloma.

Vital role of oligopeptide transporters in physiology and drug transport and their clinical relevance / 药物评价研究

The oligopeptide transporters (PEPTs),including PEPT1 and PEPT2,belong to the SLC family and are driven by H+ gradient.PEPT1,the low-affinity and high-capacity transporter,is mainly expressed in small intestine,whereas PEPT2,the high-affinity and low-capacity transporter,is mainly expressed in kidney,brain and lung and has a broader distribution in the organism.The PEPTs are responsible for the absorption and conservation of dietary protein digestion products in intestine and kidney,respectively,and in maintaining homeostasis of neuropeptides in brain.They are also responsible for the absorption and disposition of a number of pharmacologically important compounds including some aminocephalosporins,angiotensin-converting enzyme inhibitors,antiviral prodrugs and others.And PEPTs are also associated with some intestinal diseases and cancer.Therefore,this article summarizes the important role of PEPTs in physiology and drug transport and their clinical relevance.

Design, Synthesis and Antiviral Activity of Novel EV71 3C Protease Inhibitors / 中国药师

Objective:To explore novel compounds with anti-EV71 activity. Methods: A series of oligopeptides were designed based on the active groove of the EV71 3C protease using molecular simulation technology. Furthermore, some oligopeptides were syn-thesized and tested for the inhibition ability against EV71 in vitro. Results:Pentapeptides had higher binding affinity to the EV71 3C protease than the other oligopeptides, such as compounds 25 and 16. Therefore, compounds 25 and 16 were synthesized and tested in vitro for the anti-EV71 activity, and compound 25 exhibited potent anti-EV71 activity(EC50 =1. 36 μmol·L-1, CC50 =211. 94 μmol ·L-1, SI=155. 84), while compound 16 had no evident effect on EV71. Conclusion: It is worthy of further investigation on com-pound 25 as a novel scaffold of anti-EV71inhibitor.

Effects of Oligo-peptide I-C-F-6 in Carapax Trionycis on Rats with Liver Fibrosis Induced by CCl4 / 中国中医药信息杂志

Objective To study effects of oligo-peptide I-C-F-6 in carapax trionycis on rats with liver fibrosis induced by CCl4;To discuss its anti-liver fibrosis effects and possible mechanisms. Methods Forty-eight SD male rats were randomly divided into normal control group, model group, bifendate group, and oligo-peptide I-C-F-6 group, 12 in each group.CCl4 was injected intraperitoneally to build rat liver fibrosis model.Oligo-peptide I-C-F-6 group and bifendate group were given subcutaneous injection of oligo-peptide I-C-F-6 (0.12μg/g) or bifendate (0.12μg/g). At the same time, normal control group and model group were giventhe same volume of saline for seven weeks. The levels ofALT, AST,MDA, SOD, IL-4, IL-10 and TNF-α were tested.The histomorphology changes were observed under optical microscopeby HE, and the expressions of transforming growth TGF-β1 were determined by immunohistochemistry.Results Compared with model group, serum levels of ALT and AST were reduced evidently in oligo-peptide I-C-F-6 group. Hepatic content of MDA, IL-4 and TNF-α decreased, while SOD activity and IL-10 were found significantly increased. Liver fibrosis was ameliorated significantly. Hepatic expressions of TGF-β1 were weakly positive.Conclusion Oligo-peptide I-C-F-6 can ameliorate hepatocyte damage of model rats, thus it has anti-oxidative and anti-liver fibrosis effects on liver fibrosis in rats.

Functional expression of oligopeptide transporter PepT1 in the gastrointestinal tract and its regulatory factors / 中华临床营养杂志

Many peptide transporters have been identified in mammals, among which PepT1 has been widely studied. PepT1, a member of proton-coupled oligopeptide transporter (POT) superfamily, is a peptide transporter of low affinity and high capacity and is mainly expressed in the brush border membrane of intestinal epithelial cells. PepT1 plays an important role in the absorption of di/tri-peptide (the degradation products of protein in intestinal tract). Meanwhile, it mediates the transport of peptide-like drugs and the bacterial products. Therefore,the changes of the functional expression of PepT1 in the gastrointestinal tract may dramatically affect the internal and external environmental stability and drug absorption. This paper reviews the structural features and function,distribution, transport mechanisms, and regulatory factors of PepT1.

Distribution and biological role of the oligopeptide-binding protein (OppA) in Xanthomonas species

In this study we investigated the prevalence of the oppA gene, encoding the oligopeptide binding protein (OppA) of the major bacterial oligopeptide uptake system (Opp), in different species of the genus Xanthomonas. The oppA gene was detected in two Xanthomonas axonopodis strains among eight tested Xanthomonas species. The generation of an isogenic oppA-knockout derivative of the Xac 306 strain, showed that the OppA protein neither plays a relevant role in oligopeptide uptake nor contributes to the infectivity and multiplication of the bacterial strain in leaves of sweet orange (Citrus sinensis) and Rangpur lime (Citrus limonia). Taken together these results suggest that the oppA gene has a recent evolutionary history in the genus and does not contribute in the physiology or pathogenesis of X. axonopodis.

Tissue Reaction to Synthetic Oligopeptide Derived from Enamel Matrix Derivative in Rats / Oral Science International

<i>Background:</i> Enamel matrix derivative placed in the backs of rats induces numerous eosinophilic round bodies (ERBs) and hard tissue. ERBs were analyzed by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and by database analysis. Subsequently, a seven-amino-acid sequence was identified, and an artificial oligopeptide was synthesized with its sequence. The present experiment was carried out to clarify whether or not the peptide induces hard tissue formation <i>in vivo</i>.<i>Methods:</i> Synthetic oligopeptide was injected into the backs of 15 rats. After injection, the tissues were excised at various times and prepared for light and immune-light microscopy.<i>Results:</i> A white lump was macroscopically observed in each rat back 14 days after injection of 7.5 and 15 mg/mL synthetic oligopeptide, and endochondral ossification and bone formation were microscopically observed in one rat back 14 days after injection of 15 mg/mL synthetic oligopeptide.<i>Conclusions:</i> The synthetic oligopeptide is pure, 1,118 dalton, and apparently low-toxicity. It seems to produce hard tissues, such as cartilage and bone tissue.

Repair of Rabbit Femoral Defects with a Novel BMP2-derived Oligopeptide P24 / 华中科技大学学报（医学）（英德文版）

In this study, the bioactivity of a novel BMP2-derived oligopeptide P24 was investigated by using the model of rabbit femoral defect after loaded in the biodegradable poly (lactic acid / glycolic acid / asparagic acid-co-polyethylene glycol) (PLGA-[ASP-PEG]). A 1.5-cm unilateral segmental bone defect was created in the left femoral diaphysis in each of the 30 new zealand white rabbits.The defects of 18 legs filled with BMP2-derived peptide P24 combined with PLGA-[ASP-PEG]scaffold serves as the experimental group, and the defects in the rest 12 rabbits filled with(PLGA-[ASP-PEG]) without P24 as control group. The bone-repairing capability in the target region of the two group was grossly, radiologically, histopathologically and biomechanically evaluated 4, 8and 12 weeks after the operation. Our results showed that in each group, primary healing of incision was achieved in the two groups. Radiographically, in experimental group, defects were filled with induced callus within 8 weeks, and a cortical bone-like structure was observed in some animals at the12th week. According to the standardized stage of bone defect repair, 9 (64.28%) achieved grade-4healing. In contrast, little bone formation was seen in the defects even 12 weeks after the operation,and 5 (62.50%) had grade 0 healing in this group. Histologically, tissue engineering material was mostly absorbed and cartilage was found around implants in the experimental group at the 4th week;8 weeks after operation, the engineering material was completely absorbed, and formation of woven bone was observed and typical trabecular bone structure could be seen. In control group, 8 weeks after operation, the defect was filled with fibrous tissues, and no bone-like structure was observed. Statistical analysis showed very significant difference in biomechanical indicators between the two groups (P＜0.05). It is concluded that new oligopeptide P24 can induce excellent bone regeneration and promote bone repair.

Determination of affinities of oligopeptides binding with p65 and identification of their inhibiting effect on DNA binding activity of NF-?B / 第三军医大学学报

Objective To determine the affinities of five oligopeptides specifically binding with DNA binding domain of NF-?B p65 subunit and identify their inhibiting effect on DNA binding activity of NF-?B. Methods By using biosensor the affinities were measured by means of kinetic analysis, and the inhibiting effects were determined by competitive ELISA. Results The results of biosensor showed that all of five oligopeptides really possessed the capability of specific interacting with NF-?B p65 subunit. The affinity constants of these oligopeptides were 2.67?10~ -7 mol/L, 9.02?10~ -6 mol/L, 1.07?10~ -6 mol/L, 8.03?10~ -6 mol/L, 9.83?10~ -7 mol/L respectively. The results of competitive ELISA indicated that five oligopeptides could inhibit NF-?B from binding with ?B motif, and their inhibiting effect depended on their concentration. Conclusion Five oligopeptides that were screened by yeast two-hybrid system method can really interact with p65, and possess the inhibiting effect on DNA binding activity of NF-?B. So it will be possible that these oligopeptides are regarded as model to design and develop novel anti-inflammatory peptide drug targeting NF-?B.

Synthesis of oligopeptide of HDV antigen and its application in diagnosis / 第三军医大学学报

A 27-peptide,a fragment of hepatitis delta antigen(HDAg),was synthesized and used to develop an ELISA method for ihe detection of anti-HD.It was found that positive anti-HD reaction occurred between the coated 27-peptide and a stored sample of serum which was known anti-HD positive.Absorption test revealed that the synthetic peptide competed with natural HDAg for anti-HD,suggesting that the peptide possessed the antigenicity similar to that of natural HDAg.The antigenicity of the synthetic peptide was quite specific wihtout cross reaction with normal human and mouse sera and with anti-HA.anti-HB and anti-HC sera.Among 300 blood donors,there was only 1 case(0.33%)anti-HD positive with an ALT level 2 times higher than normal.In 41 cases of non-B hepatitis and 52 cases of HAV hepatitis,none was anti-HD positive.In 211 cases of various types of HBV hepatitis,21 were(9.95%)anti-HD positive,among whom 2/82(2.5%)werehealthy HBV carriers,6/43(13.95%)were patients with a-cute icteric hepatitis,6/60(10.00%)were patients of chronic active hepatitis,4/18(22.20%)were patients of severe hepatitis,and 3/8(37.50%)were those with liver cirrhosis.These results were consistent with those in our previous reports.