Whooping cough is a severe childhood disease, caused by the bacterium , which releases pertussis toxin (PT) as a major virulence factor. Previously, we identified the human antimicrobial peptides α-defensin-1 and -5 as inhibitors of PT and demonstrated their capacity to inhibit the activity of the PT enzyme subunit PTS1. Here, the underlying mechanism of toxin inhibition was investigated in more detail, which is essential for developing the therapeutic potential of these peptides. Flow cytometry and immunocytochemistry revealed that α-defensin-5 strongly reduced PT binding to, and uptake into cells, whereas α-defensin-1 caused only a mild reduction. Conversely, α-defensin-1, but not α-defensin-5 was taken up into different cell lines and interacted with PTS1 inside cells, based on proximity ligation assay. In-silico modeling revealed specific interaction interfaces for α-defensin-1 with PTS1 and vice versa, unlike α-defensin-5. Dot blot experiments showed that α-defensin-1 binds to PTS1 and even stronger to its substrate protein Gαi in vitro. NADase activity of PTS1 in vitro was not inhibited by α-defensin-1 in the absence of Gαi. Taken together, these results suggest that α-defensin-1 inhibits PT mainly by inhibiting enzyme activity of PTS1, whereas α-defensin-5 mainly inhibits cellular uptake of PT. These findings will pave the way for optimization of α-defensins as novel therapeutics against whooping cough.
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http://dx.doi.org/10.3390/ijms241310557 | DOI Listing |
Lancet Glob Health
January 2025
Centre for Neonatal and Paediatric Infection and Vaccine Institute, City St George's, University of London, London, UK; Makerere University-Johns Hopkins University Research Collaboration, Kampala, Uganda; UK Health Security Agency, Salisbury, UK.
Background: Immunisation in pregnancy against pertussis can reduce severe disease in infancy. There are few data on the safety and immunogenicity of vaccines given to pregnant women living with HIV and their infants. We aimed to describe the safety and immunogenicity of a tetanus-diphtheria-acellular pertussis (TdaP) vaccine containing genetically detoxified pertussis toxin given to pregnant women living with HIV and the effect of the vaccine on infant whole-cell pertussis vaccine responses.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Institute of Biomedicine, University of Turku, Turku, Finland.
Enzyme promiscuity is the ability of an enzyme to catalyze an unexpected side reaction in addition to its main reaction. Here, we describe a biocatalytic process to produce non-hydrolyzable NAD+ analogs based on the ADP-ribosyltransferase (ART) activity of pertussis toxin PtxS1 subunit. First, in identical manner to normal catalysis, PtxS1 activates NAD+ to form the reactive oxocarbenium cation.
View Article and Find Full Text PDFACS Pharmacol Transl Sci
December 2024
Synovo GmbH, Paul-Ehrlich-Straße 15, 72076 Tübingen, Germany.
Background: Myelin oligodendrocyte glycoprotein 35-55 (MOG)-peptide induced experimental autoimmune encephalomyelitis (EAE) is a model for inflammation of the brain and spinal cord. However, its severity and incidence vary within and between laboratories. Severe scores can lead to premature termination and are both unnecessary for readouts and detrimental to animal welfare.
View Article and Find Full Text PDFFASEB J
December 2024
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
G-protein-coupled receptor 41 (GPR41) is a Gα-coupled receptor activated by short-chain fatty acids (SCFAs). Here, we tested that GPR41 is also expressed in cardiomyocytes and exerts a direct negative inotropic effect when activated by SCFA butyrate. Primary cardiomyocytes were isolated from wild-type (WT) and GPR41 knockout (GPR41) adult mice and intracellular Ca concentration and cell shortening were measured using the IonOptix system.
View Article and Find Full Text PDFPediatr Infect Dis J
December 2024
From the Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
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