Human African trypanosomiasis or sleeping sickness, caused by the protozoan parasite Trypanosoma brucei, is characterized by the manipulation of the host's immune response to ensure parasite invasion and persistence. Uncovering key molecules that support parasite establishment is a prerequisite to interfere with this process. We identified Q586B2 as a T.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2022
Nanobodies and chemical cross-linking were used to gain information on the identity and positions of flexible domains of PI3Kα. The application of chemical cross-linking mass spectrometry (CXMS) facilitated the identification of the p85 domains BH, cSH2, and SH3 as well as their docking positions on the PI3Kα catalytic core. Binding of individual nanobodies to PI3Kα induced activation or inhibition of enzyme activity and caused conformational changes that could be correlated with enzyme function.
View Article and Find Full Text PDFMatrix metalloproteinase-2 (MMP-2) is an endopeptidase involved in cardiovascular disease and cancer. To date, no highly selective MMP-2 inhibitors have been identified for potential use in humans. Aim of our work was to apply the nanobody technology to the generation of highly selective inhibitors of human MMP-2 and to assess their effects on platelet function and their applicability as conjugated nanobodies.
View Article and Find Full Text PDFHuman toxocariasis is a zoonosis resulting from the migration of larval stages of the dog parasite Toxocara canis into the human paratenic host. Despite its well-known limitations, serology remains the most important tool to diagnose the disease. Our objective was to employ camelid single domain antibody fragments also known as nanobodies (Nbs) for a specific and sensitive detection of Toxocara canis excretory/secretory (TES) antigens.
View Article and Find Full Text PDFCampylobacteriosis is a widespread infectious disease, leading to a major health and economic burden. Chickens are considered as the most common infection source for humans. Campylobacter mainly multiplies in the mucus layer of their caeca.
View Article and Find Full Text PDFCampylobacter infections are among the most prevalent foodborne infections in humans, resulting in a massive disease burden worldwide. Broilers have been identified as the major source of campylobacteriosis and reducing Campylobacter loads in the broiler caeca has been proposed as an effective measure to decrease the number of infections in humans. Failure of current methods to control Campylobacter in broilers stresses the urgency to develop novel mitigation measures.
View Article and Find Full Text PDFAlthough trypsin-like serine proteases have flexible surface-exposed loops and are known to adopt higher and lower activity conformations, structural determinants for the different conformations have remained largely obscure. The trypsin-like serine protease, urokinase-type plasminogen activator (uPA), is central in tissue remodeling processes and also strongly implicated in tumor metastasis. We solved five X-ray crystal structures of murine uPA (muPA) in the absence and presence of allosteric molecules and/or substrate-like molecules.
View Article and Find Full Text PDFThe ephrin receptor A4 (EphA4) is one of the receptors in the ephrin system that plays a pivotal role in a variety of cell-cell interactions, mostly studied during development. In addition, EphA4 has been found to play a role in cancer biology as well as in the pathogenesis of several neurological disorders such as stroke, spinal cord injury, multiple sclerosis, amyotrophic lateral sclerosis (ALS), and Alzheimer's disease. Pharmacological blocking of EphA4 has been suggested to be a therapeutic strategy for these disorders.
View Article and Find Full Text PDFPlacental growth factor (PlGF), a member of vascular endothelial growth factors (VEGF) family, is considered as an important antigen associated with pathological conditions such as cancer cell growth, and metastasis. PlGF-targeting via nanobody (Nb) therefore could be beneficial to modulate these pathologies. In this work, phage-display and computational approach was employed to develop a high affinity PlGF-specific Nb.
View Article and Find Full Text PDFPlasminogen activator inhibitor 1 (PAI-1) is the principal physiological inhibitor of tissue-type plasminogen activator (t-PA) and has been identified as a risk factor in cardiovascular diseases. In order to generate nanobodies against PAI-1 to interfere with its functional properties, we constructed three nanobody libraries upon immunisation of three alpacas with three different PAI-1 variants. Three panels of nanobodies were selected against these PAI-1 variants.
View Article and Find Full Text PDFMalignant gliomas are among the rarest brain tumours, and they have the worst prognosis. Grade IV astrocytoma, known as glioblastoma multiforme (GBM), is a highly lethal disease where the standard therapies of surgery, followed by radiation and chemotherapy, cannot significantly prolong the life expectancy of the patients. Tumour recurrence shows more aggressive form compared to the primary tumour, and results in patient survival from 12 to 15 months only.
View Article and Find Full Text PDFThe p53 transcription factor plays an important role in genome integrity. To perform this task, p53 regulates the transcription of genes promoting various cellular outcomes including cell cycle arrest, apoptosis or senescence. The precise regulation of this activity remains elusive as numerous mechanisms, e.
View Article and Find Full Text PDFThe biologically and clinically important membrane transporters are challenging proteins to study because of their low level of expression, multidomain structure, and complex molecular dynamics that underlies their activity. ATP7B is a copper transporter that traffics between the intracellular compartments in response to copper elevation. The N-terminal domain of ATP7B (N-ATP7B) is involved in binding copper, but the role of this domain in trafficking is controversial.
View Article and Find Full Text PDFHemiscorpius lepturus scorpionism poses one of the most dangerous health problems in many parts of the world. The common therapy consists of using antivenom antibody fragments derived from a polyclonal immune response raised in horses. However, this immunotherapy creates serious side effects, including anaphylactic shock sometimes even leading to death.
View Article and Find Full Text PDFInvadopodia are actin-rich protrusions arising through the orchestrated regulation of precursor assembly, stabilization, and maturation, endowing cancer cells with invasive properties. Using nanobodies (antigen-binding domains of Camelid heavy-chain antibodies) as perturbators of intracellular functions and/or protein domains at the level of the endogenous protein, we examined the specific contribution of fascin and cortactin during invadopodium formation in MDA-MB-231 breast and PC-3 prostate cancer cells. A nanobody (K(d)~35 nM, 1:1 stoichiometry) that disrupts fascin F-actin bundling emphasizes the importance of stable actin bundles in invadopodium array organization and turnover, matrix degradation, and cancer cell invasion.
View Article and Find Full Text PDFOne of the main disadvantages of current t-PA thrombolytic treatment is the increased bleeding risk. Upon activation, thrombin activatable fibrinolysis inhibitor (TAFI) is a very powerful antifibrinolytic enzyme. Therefore, co-administration of a TAFI inhibitor during thrombolysis could reduce the required t-PA dose without compromising the thrombolytic efficacy.
View Article and Find Full Text PDFIntroduction: Aberrant turnover of the actin cytoskeleton is intimately associated with cancer cell migration and invasion. Frequently however, evidence is circumstantial, and a reliable assessment of the therapeutic significance of a gene product is offset by lack of inhibitors that target biologic properties of a protein, as most conventional drugs do, instead of the corresponding gene. Proteomic studies have demonstrated overexpression of CapG, a constituent of the actin cytoskeleton, in breast cancer.
View Article and Find Full Text PDFBackground: Gene regulatory processes are largely resulting from binding of transcription factors to specific genomic targets. Leucine-responsive Regulatory Protein (Lrp) is a prevalent transcription factor family in prokaryotes, however, little information is available on biological functions of these proteins in archaea. Here, we study genome-wide binding of the Lrp-like transcription factor Ss-LrpB from Sulfolobus solfataricus.
View Article and Find Full Text PDFNanobodies are recombinant, antigen-specific, single-domain, variable fragments of camelid heavy chain-only antibodies. The innate supremacy of nanobodies as a renewable source of affinity reagents, together with their high production yield in a broad variety of expression systems, minimal size, great stability, reversible refolding and outstanding solubility in aqueous solutions, and ability to specifically recognize unique epitopes with subnanomolar affinity, have combined to make them a useful class of biomolecules for research and various medical diagnostic and therapeutic applications. This article speculates on a number of technological innovations that might be introduced in the nanobody identification platform to streamline the generation of more potent nanobodies and to expand their application range.
View Article and Find Full Text PDFThe preparation of a V(H)H (nanobody) named IH4 that recognizes human glycophorin A (GPA) is described. IH4 was isolated by screening a library prepared from the lymphocytes of a dromedary immunized by human blood transfusion. Phage display and panning against GPA as the immobilized antigen allowed isolating this V(H)H.
View Article and Find Full Text PDFNanobodies® are single-domain antibody fragments derived from camelid heavy-chain antibodies. Because of their small size, straightforward production in Escherichia coli, easy tailoring, high affinity, specificity, stability and solubility, nanobodies® have been exploited in various biotechnological applications. A major challenge in the post-genomics and post-proteomics era is the identification of regulatory networks involving nucleic acid-protein and protein-protein interactions.
View Article and Find Full Text PDFAngiogenesis targeting is an attractive approach for cancer treatment. Vascular endothelial growth factor receptor 2 (VEGFR2) is such an important target that is overexpressed in tumor vasculature compared to the endothelium cells of resting blood vessels and blocking of its signaling inhibits neovascularization and tumor metastasis. Immunotoxins represent a promising group of targeted therapeutics to combat tumors.
View Article and Find Full Text PDFImmunizing a camelid (camels and llamas) with soluble, properly folded proteins raises an affinity-matured immune response in the unique camelid heavy-chain only antibodies (HCAbs). The peripheral blood lymphocytes of the immunized animal are used to clone the antigen-binding antibody fragment from the HCAbs in a phage display vector. A representative aliquot of the library of these antigen-binding fragments is used to retrieve single domain antigen-specific binders by successive rounds of panning.
View Article and Find Full Text PDFChromatin immunoprecipitation (ChIP), followed by microarray hybridization (ChIP-chip) or high-throughput sequencing (ChIP-seq), is becoming a widely used powerful method for the analysis of the in vivo DNA-protein interactions at genomic scale.The success of ChIP largely depends on the quality of antibodies. Although polyclonal antibodies have been successfully used for ChIP, their production requires regular immunization and they exhibit high aspecificity and batch to batch variability.
View Article and Find Full Text PDFVascular endothelial growth factor receptor-2 (VEGFR2) is an important tumor-associated receptor and blockade of the VEGF receptor signaling can lead to the inhibition of neovascularization and tumor metastasis. Nanobodies are the smallest intact antigen binding fragments derived from heavy chain-only antibodies occurring in camelids. Here, we describe the identification of a VEGFR2-specific Nanobody, named 3VGR19, from dromedaries immunized with a cell line expressing high levels of VEGFR2.
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