Search results for "molecular mimicry"

Molecular mimicry in the post-COVID-19 signs and symptoms of neurovegetative disorders?

2021

Many individuals who have severe forms of COVID-19 experience a suite of neurovegetative signs and symptoms (eg, tachycardia) after their recovery, suggesting that the imbalance of the sympathetic-parasympathetic activity of the autonomic nervous system1 could continue for many weeks or months after respiratory symptoms stop. Moreover, a reduction of the parasympathetic tone could have a role in restricting the cholinergic anti-inflammatory pathway, thus favouring hyperinflammation and cytokine storm in the most severe phases of the disease. As reported by Guglielmo Lucchese in The Lancet Microbe,2 SARS-CoV-2 can damage the nervous system via an indirect mechanism, resulting in a high preva…

Immune evasion, immunopathology and the regulation of the immune system.

2013

21 pages; International audience; Costs and benefits of the immune response have attracted considerable attention in the last years among evolutionary biologists. Given the cost of parasitism, natural selection should favor individuals with the most effective immune defenses. Nevertheless, there exists huge variation in the expression of immune effectors among individuals. To explain this apparent paradox, it has been suggested that an over-reactive immune system might be too costly, both in terms of metabolic resources and risks of immune-mediated diseases, setting a limit to the investment into immune defenses. Here, we argue that this view neglects one important aspect of the interaction…

Synthesis of enantiopure pyrrolidine-derived peptidomimetics and oligo-beta-peptides via nucleophilic ring-opening of beta-lactams.

2006

The synthesis of the two enantiomers of pyrrolidine-derived spiro beta-lactams by resolution with D- and L-Boc phenylalanine is described. The potential of these optically active spiro beta-lactams on the synthesis of peptidomimetics as analogues of melanostatin is evaluated. Theoretical studies of several models, at the Becke3LYP/6-31+G* level of theory, together with previous experimental evidences from our group, gathered by NMR, allow us to design structures that can efficiently mimic some biologically active peptide-type molecules. On the other hand, the spiro beta-lactams have shown their utility in the preparation of beta-peptides. As an example, a homo-tetra-beta-peptide was synthes…

The Molecular Anatomy of Human Hsp60 and its Similarity with that of Bacterial Orthologs and Acetylcholine Receptor Reveal a Potential Pathogenetic R…

2012

Heat-shock protein 60 (Hsp60) is ubiquitous and highly conserved being present in eukaryotes and prokaryotes, including pathogens. This chaperonin, although typically a mitochondrial protein, can also be found in other intracellular sites, extracellularly, and in circulation. Thus, it can signal the immune system and participate in the development of inflammation and immune reactions. Both phenomena can be elicited by human and foreign Hsp60 (e.g., bacterial GroEL), when released into the blood by infectious agents. Consequently, all these Hsp60 proteins become part of a complex autoimmune response characterized by multiple cross reactions because of their structural similarities. In this s…

Functional superoxide dismutase mimics. Structural characterization and magnetic exchange interactions of copper(II)-N-substituted sulfonamide dimer …

2004

Dinuclear copper(II) complexes with N-substituted sulfonamide ligands as superoxide dismutase (SOD) mimics have been investigated. The new N-(thiazol-2-yl)toluenesulfonamide (Htz-tol) and N-(thiazol-2-yl)naphthalenesulfonamide (Htz-naf) ligands have been prepared and structurally characterized. The complexes derived from these ligands, [Cu(2)(tz-tol)(4)] (1) and [Cu(2)(tz-naf)(4)] (2), have been synthesized, and their crystal structure, magnetic properties, and EPR spectra were studied in detail. In both compounds the metal centers are bridged by four nonlinear triatomic NCN groups. The coordination geometry of the coppers in the dinuclear entity of 1 and 2 is distorted square planar with t…

Toward very potent, non-covalent organophosphonate inhibitors of cathepsin C and related enzymes by 2-amino-1-hydroxy-alkanephosphonates dipeptides

2013

Cathepsins play an important role in several human disorders and therefore the design and synthesis of their inhibitors attracts considerable interest in current medicinal chemistry approaches. Due to the presence of a strong sulphydryl nucleophile in the active center of the cysteine type cathepsins, most strategies to date have yielded covalent inhibitors. Here we present a series of non-covalent β-amino-α-hydroxyalkanephosphonate dipeptidic inhibitors of cathepsin C, ranking amongst the best low-molecular weight inhibitors of this enzyme. Their binding modes determined by molecular modelling indicate that the hydroxymethyl fragment of the molecule, not the phosphonate moiety, acts as a t…

Human parvovirus B19 infection and antiphospholipid antibodies

2007

Erythema infectiosum is the main manifestation of human parvovirus B19 infections. Further B19-related diseases commonly associated with the acute infection are flue-like symptoms, transient aplastic crisis, transient arthralgias, leukopenia and thrombocytopenia, spontaneous abortion and hydrops fetalis in pregnant women. Hepatitis, myocarditis, meningitis, encephalitis as well as pure red cell anemia may occur occasionally. In addition parvovirus B19 infections have been frequently described as cause or trigger of various forms of autoimmune diseases affecting all blood cell lines, joints, connective tissue, uvea, large and small vessels. Molecular mimicry may be one major contribution to …

Application of 3-Quinolinoyl Picket Porphyrins to the Electroreduction of Dioxygen to Water: Mimicking the Active Site of Cytochromec Oxidase

2001

International audience

Coiled-Coil Lipopeptides Mimicking the Prehairpin Intermediate of Glycoprotein gp41

2009

T Cell Receptor Mimic Peptidesand Their Potential Application in T-Cell-Mediated Diseas e

2001

<i>Background:</i> A T cell receptor (TCR) peptide was designed that mimics the intramembranous amino acid sequence of the TCR chain. Prior studies had shown that this mimic peptide would inhibit TCR signaling. This study was designed to investigate the use of this mimic peptide for the treatment of T-cell-mediated skin diseases. <i>Methods:</i> Synthesized mimic peptides were first tested for their T-cell-inhibitory effect in proliferation assays. Afterwards, mimic peptides were applied to murine ear skin prior to application of a contact allergen and tested for their inhibitory effect in the model of murine allergic contact sensitivity. The effect of epicutaneous t…