scholarly journals Synthesis, Formulation, and Adjuvanticity of Monodesmosidic Saponins with Olenanolic Acid, Hederagenin and Gypsogenin Aglycones, and some C-28 Ester Derivatives

2020 ◽  
Author(s):  
BW Greatrex ◽  
Alison Daines ◽  
S Hook ◽  
DH Lenz ◽  
W McBurney ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Self Assembly ◽  
Vaccine Adjuvant ◽  
Choline Ester ◽  
Activation Markers ◽  
Murine Bone Marrow ◽  
Transmission Electron ◽  
High Concentrations ◽  
Sugar Stereochemistry

© 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. In an attempt to discover a new synthetic vaccine adjuvant, the glycosylation of hederagenin, gypsogenin, and oleanolic acid acceptors with di- and trisaccharide donors to generate a range of mimics of natural product QS-21 was carried out. The saponins were formulated with phosphatidylcholine and cholesterol, and the structures analyzed by transmission electron microscopy. 3-O-(Manp(1→3)Glcp)hederagenin was found to produce numerous ring-like micelles when formulated, while C-28 choline ester derivatives preferred self-assembly and did not interact with the liposomes. When alone and in the presence of cholesterol and phospholipid, the choline ester derivatives produced nanocrystalline rods or helical micelles. The effects of modifying sugar stereochemistry and the aglycone on the immunostimulatory effects of the saponins was then evaluated using the activation markers MHC class II and CD86 in murine bone marrow dendritic cells. The most active saponin, 3-O-(Manp(1→3)Glcp)hederagenin, was stimulatory at high concentrations in cell culture, but this did not translate to strong responses in vivo.

scholarly journals Synthesis, Formulation, and Adjuvanticity of Monodesmosidic Saponins with Olenanolic Acid, Hederagenin and Gypsogenin Aglycones, and some C-28 Ester Derivatives

2020 ◽  
Author(s):  
BW Greatrex ◽  
Alison Daines ◽  
S Hook ◽  
DH Lenz ◽  
W McBurney ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Self Assembly ◽  
Vaccine Adjuvant ◽  
Choline Ester ◽  
Activation Markers ◽  
Murine Bone Marrow ◽  
Transmission Electron ◽  
High Concentrations ◽  
Sugar Stereochemistry

© 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. In an attempt to discover a new synthetic vaccine adjuvant, the glycosylation of hederagenin, gypsogenin, and oleanolic acid acceptors with di- and trisaccharide donors to generate a range of mimics of natural product QS-21 was carried out. The saponins were formulated with phosphatidylcholine and cholesterol, and the structures analyzed by transmission electron microscopy. 3-O-(Manp(1→3)Glcp)hederagenin was found to produce numerous ring-like micelles when formulated, while C-28 choline ester derivatives preferred self-assembly and did not interact with the liposomes. When alone and in the presence of cholesterol and phospholipid, the choline ester derivatives produced nanocrystalline rods or helical micelles. The effects of modifying sugar stereochemistry and the aglycone on the immunostimulatory effects of the saponins was then evaluated using the activation markers MHC class II and CD86 in murine bone marrow dendritic cells. The most active saponin, 3-O-(Manp(1→3)Glcp)hederagenin, was stimulatory at high concentrations in cell culture, but this did not translate to strong responses in vivo.

scholarly journals Targeting Toll-Like Receptor 2: Polarization of Porcine Macrophages by a Mycoplasma-Derived Pam2cys Lipopeptide

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 692
Author(s):  
Giulia Franzoni ◽  
Antonio Anfossi ◽  
Chiara Grazia De Ciucis ◽  
Samanta Mecocci ◽  
Tania Carta ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Macrophage Polarization ◽  
Surface Protein ◽  
Antimicrobial Activities ◽  
Toll Like Receptor ◽  
Activation Markers ◽  
Class I Mhc ◽  
Toll Like Receptor 2

Toll-like receptor 2 (TLR2) ligands are attracting increasing attention as prophylactic and immunotherapeutic agents against pathogens and tumors. We previously observed that a synthetic diacylated lipopeptide based on a surface protein of Mycoplasma agalactiae (Mag-Pam2Cys) strongly activated innate immune cells, including porcine monocyte-derived macrophages (moMΦ). In this study, we utilized confocal microscopy, flow cytometry, multiplex cytokine ELISA, and RT-qPCR to conduct a comprehensive analysis of the effects of scalar doses of Mag-Pam2Cys on porcine moMΦ. We observed enhanced expression of activation markers (MHC class I, MHC class II DR, CD25), increased phagocytotic activity, and release of IL-12 and proinflammatory cytokines. Mag-Pam2Cys also upregulated the gene expression of several IFN-α subtypes, p65, NOS2, and molecules with antimicrobial activities (CD14, beta defensin 1). Overall, our data showed that Mag-Pam2Cys polarized porcine macrophages towards a proinflammatory antimicrobial phenotype. However, Mag-Pam2Cys downregulated the expression of IFN-α3, six TLRs (TLR3, -4, -5, -7, -8, -9), and did not interfere with macrophage polarization induced by the immunosuppressive IL-10, suggesting that the inflammatory activity evoked by Mag-Pam2Cys could be regulated to avoid potentially harmful consequences. We hope that our in vitro results will lay the foundation for the further evaluation of this diacylated lipopeptide as an immunopotentiator in vivo.

Hollow Microcapsules Through Layer-by-Layer Self-Assembly of Chitosan/Alginate on E. coli

MRS Advances ◽  
2020 ◽  
Vol 5 (46-47) ◽  
pp. 2401-2407
Author(s):  
Michael Y. Yitayew ◽  
Maryam Tabrizian
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Layer By Layer ◽  
E Coli ◽  
Fluorescence Measurements ◽  
Transmission Electron ◽  
Imaging Probes ◽  
Delivery Platform ◽  
20 Nm

AbstractHollow microcapsules prepared via layer-by-layer (LbL) self-assembled polyelectrolytes are prevalent biomaterials in the synthesis of biocompatible delivery systems for drugs, imaging probes, and other macromolecules to control biodistribution and lower toxicity in vivo. The use of LbL self-assembly for the synthesis of these capsules provides several benefits including ease of fabrication, abundance in choice of substrates and coating material, as well as application-specific tunability. This study explores the development of hollow microcapsules by LbL assembly of chitosan and alginate onto live E. coli cells, and also provides a proof-of-concept of this capsule as a delivery platform through the encapsulation of quantum dots as a cargo. The study found that robust bilayers of chitosan/alginate can be formed onto the core substrate (E. coli) containing quantum dots as demonstrated with zeta potential analysis. Confocal microscopy was used to verify cell viability and the internalization of quantum dots into the cells as well as confirmation of the coating using fluorescein-labelled chitosan. Furthermore, transmission electron microscopy (TEM) was used to analyse cells coated with four-bilayers and showed a uniform coating morphology with a capsule thickness of 10-20 nm, which increased to 20-50 nm for hollow capsules after cell lysis. Quantum dot retention in the capsules was demonstrated using fluorescence measurements. Overall, the study shows promising results of a novel fabrication method for hollow microcapsules that uses biocompatible polymers and mild core dissolution conditions using cell templates with applications in sustained release of therapeutics and imaging probes.

scholarly journals Anatomy of a selectively coassembled β-sheet peptide nanofiber

2020 ◽  
Vol 117 (9) ◽  
pp. 4710-4717 ◽  
Author(s):  
Qing Shao ◽  
Kong M. Wong ◽  
Dillon T. Seroski ◽  
Yiming Wang ◽  
Renjie Liu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Molecular Level ◽  
Form And Function ◽  
Transmission Electron ◽  
Peptide Pair ◽  
High Concentrations ◽  
Dynamics Simulations ◽  
And Function ◽  
20 Nm ◽  
Β Sheet

Peptide self-assembly, wherein molecule A associates with other A molecules to form fibrillar β-sheet structures, is common in nature and widely used to fabricate synthetic biomaterials. Selective coassembly of peptide pairs A and B with complementary partial charges is gaining interest due to its potential for expanding the form and function of biomaterials that can be realized. It has been hypothesized that charge-complementary peptides organize into alternating ABAB-type arrangements within assembled β-sheets, but no direct molecular-level evidence exists to support this interpretation. We report a computational and experimental approach to characterize molecular-level organization of the established peptide pair, CATCH. Discontinuous molecular dynamics simulations predict that CATCH(+) and CATCH(−) peptides coassemble but do not self-assemble. Two-layer β-sheet amyloid structures predominate, but off-pathway β-barrel oligomers are also predicted. At low concentration, transmission electron microscopy and dynamic light scattering identified nonfibrillar ∼20-nm oligomers, while at high concentrations elongated fibers predominated. Thioflavin T fluorimetry estimates rapid and near-stoichiometric coassembly of CATCH(+) and CATCH(−) at concentrations ≥100 μM. Natural abundance13C NMR and isotope-edited Fourier transform infrared spectroscopy indicate that CATCH(+) and CATCH(−) coassemble into two-component nanofibers instead of self-sorting. However,13C–13C dipolar recoupling solid-state NMR measurements also identify nonnegligible AA and BB interactions among a majority of AB pairs. Collectively, these results demonstrate that strictly alternating arrangements of β-strands predominate in coassembled CATCH structures, but deviations from perfect alternation occur. Off-pathway β-barrel oligomers are also suggested to occur in coassembled β-strand peptide systems.

scholarly journals Self-assembly of spectrin oligomers in vitro: a basis for a dynamic cytoskeleton.

1981 ◽  
Vol 88 (2) ◽  
pp. 463-468 ◽  
Author(s):  
J S Morrow ◽  
V T Marchesi
Keyword(s):  
Self Assembly ◽  
Erythrocyte Membranes ◽  
Membrane Structure And Function ◽  
High Concentrations ◽  
The Stability ◽  
And Function ◽  
Low Ionic Strength ◽  
Affinity Interaction

Purified human erythrocyte spectrin is able to form large oligomeric species without the collaboration of any other proteins. This reversible self-assembly process is both temperature and concentration dependent and seems to be mediated by the same kinds of low affinity noncovalent associations between spectrin monomers that promote tetramer formation. Low ionic strength extracts of erythrocyte membranes also contain these oligomeric species. These results support the idea that spectrin oligomers and the factors that regulate their formation may be responsible for both the stability and the versatility of the erythrocyte membrane cytoskeleton. It is postulated that the high concentrations of spectrin necessary for oligomerization are maintained in vivo by a high-affinity interaction with ankyrin. Such a coupling of high and low affinity interactions in multifunctional proteins may have significant implications for membrane structure and function.

scholarly journals Relief from Zmp1-Mediated Arrest of Phagosome Maturation Is Associated with Facilitated Presentation and Enhanced Immunogenicity of Mycobacterial Antigens

2011 ◽  
Vol 18 (6) ◽  
pp. 907-913 ◽  
Author(s):  
Pål Johansen ◽  
Antonia Fettelschoss ◽  
Beat Amstutz ◽  
Petra Selchow ◽  
Ying Waeckerle-Men ◽  
...  
Keyword(s):  
T Cell ◽  
Mhc Class Ii ◽  
Delayed Type Hypersensitivity ◽  
Mycobacterial Antigen ◽  
Phagosome Maturation ◽  
Content Type ◽  
Murine Bone Marrow ◽  
Zinc Metalloprotease ◽  
Mycobacterial Antigens

ABSTRACTPathogenic mycobacteria escape host innate immune responses by blocking phagosome-lysosome fusion. Avoiding lysosomal delivery may also be involved in the capacity of mycobacteria to evade major histocompatibility complex (MHC) class I- or II-dependent T-cell responses. In this study, we used a genetic mutant ofMycobacterium bovisBCG that is unable to escape lysosomal transfer and show that presentation of mycobacterial antigens is affected by the site of intracellular residence. Compared to infection with wild-type BCG, infection of murine bone marrow-derived dendritic cells with a mycobacterial mutant deficient in zinc metalloprotease 1 (Zmp1) resulted in increased presentation of MHC class II-restricted antigens, as assessed by activation of mycobacterial Ag85A-specific T-cell hybridomas. Thezmp1deletion mutant was more immunogenicin vivo, as measured by delayed-type hypersensitivity (DTH), antigen-specific lymphocyte proliferation, and the frequency of antigen-specific gamma interferon (IFN-γ)-producing lymphocytes of both CD4 and CD8 subsets. In conclusion, our results suggest that phagosome maturation and lysosomal delivery of BCG facilitate mycobacterial antigen presentation and enhance immunogenicity.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Hair cell changes after cationic stimulation of corti's organ

1989 ◽  
Vol 47 ◽  
pp. 798-799
Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner
Keyword(s):  
Organ Of Corti ◽  
Cross Sectional ◽  
Surface Areas ◽  
High K ◽  
Anatomical Arrangement ◽  
Cell Cytosol ◽  
High Concentrations ◽  
K Concentration ◽  
Cell Changes

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.

STEROID METABOLISM IN THE PERFUSED HUMAN PLACENTA

1978 ◽  
Vol 87 (1) ◽  
pp. 181-191 ◽  
Author(s):  
Alfred S. Wolf ◽  
Klaus A. Musch ◽  
Werner Speidel ◽  
Jürgen R. Strecker ◽  
Christian Lauritzen
Keyword(s):  
Venous Blood ◽  
Placental Lactogen ◽  
Dehydroepiandrosterone Sulphate ◽  
Metabolic Capacity ◽  
Loading Test ◽  
Lower Range ◽  
Group I ◽  
High Concentrations ◽  
Steroid Precursor

ABSTRACT A new model for the perfusion of human term-placentas has been developed for studies on the placental biogenesis of C-18 and C-19 steroids. For viability criteria, the glucose- and oxygen-consumption, regional perfusion control by dye-infusions or scanning after injection of 99Tc-labelled macroparticles, and the histological qualification were chosen. The recycled perfusate was investigated for the steroids oestrone (Oe1), oestradiol-17β (Oe2), oestriol (Oe3), 4-androstene-3,17-dione (A), testosterone (T), and human placental lactogen (HPL) by radioimmunoassay in controls and perfusions with the foetal steroid precursor dehydroepiandrosterone sulphate (DHA-S). In control perfusions, steroid hormones were found in constant ratios (Oe1:Oe2:Oe3:T:A = 30:1.5:100:0.35:1). Following the administration of 10 mg DHA-S for testing the metabolic capacity of the organ, high concentrations of Oe1 (90–720 ng/ml = 250–3970 % as compared to 100% pre-injection values) were found, shortly preceded by a rapid increase of A (66–1000 ng/ml = 100–16 000 %). A typical surge of T (5.3–147 ng/ml = 265–4640 %) preceded the normally slower increment of Oe2 (22–220 ng/ml = 1570–4330 %). The concentrations of Oe3 and HPL remained nearly unchanged. From different steroid patterns after DHA-S-load, two distinct responses of term-placentas could be differentiated: Group I (n=12) showed high concentrations of Oe1 (3200 ± 940 %), a small increase of T (1020 ± 500%), as well as low and delayed values of Oe2 (1660 ± 450%). In Group II (n = 5), values were high for T (3160 ± 1020%) and Oe2 (3300 ± 1110%), whereas Oe1 was found in a lower range (508 ± 302%). In contrast to in vivo findings in maternal venous blood after DHS-S injection to the mother, oestrone was found in perfusions as the main oestrogen fraction from DHA-S. Thus, the analysis of such metabolic differences might be of help in the interpretation of complex results from the DHA-S-loading test.

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