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How complement molecules kill bacteria

Descrizione del progetto

La demolizione batterica: i meccanismi del sistema del complemento

Fra gli strumenti più importanti del sistema immunitario quando si tratta di sbarazzarsi delle minacce batteriche c’è il sistema del complemento, una complessa rete proteica composta da circa 60 proteine presenti nel plasma sanguigno. Con l’aiuto della convertasi C5, induce la formazione del complesso di attacco alla membrana che forma pori nell’involucro della cellula batterica, provocandone il rigonfiamento e lo scoppio. Finora mancavano gli strumenti per studiare l’attività degli enzimi e i meccanismi sono in gran parte sconosciuti. Il progetto ComBact, finanziato dal Consiglio europeo della ricerca, utilizzerà il test della convertasi C5 recentemente sviluppato e gli strumenti messi a punto nell’ambito del progetto per far luce sui meccanismi molecolari dell’uccisione dei batteri da parte del sistema del complemento.

Obiettivo

This proposal aims to provide insight into how bacteria are killed by the complement system, an important part of the host immune response against bacterial infections. Complement is a large protein network in plasma that labels bacteria for phagocytosis and directly kills them via the formation of a pore-forming complex (Membrane Attack Complex (MAC)). Currently we do not understand how complement activation results in bacterial killing. This knowledge gap is mainly caused by the lack of tools to study the enzymes that trigger MAC formation: the C5 convertases.

In my lab, we recently established a novel assay system for C5 convertases that allows us for the first time to study these enzymes under purified conditions. This model, combined with my expertise in microbiology, places my lab in a unique position to understand C5 convertase biology (Aim 1), determine the enzyme's role in MAC functioning (Aim 2) and elucidate how the MAC kills bacteria (Aim 3). Thus, I aim to provide insight into the molecular events necessary for bacterial killing by the complement system.

I will use biochemical, structural and microbiological approaches to elucidate the precise molecular arrangement of C5 convertases in vitro and on bacterial cells. I will generate unique tools to study how C5 convertases regulate MAC insertion into bacterial membranes. Finally, I will engineer fluorescent bacteria and labeled complement proteins to perform advanced microscopy analyses of how MAC kills bacteria.

These insights will lead to fundamental knowledge about the functioning of complement and will create new avenues for blocking the undesired complement activation during systemic infections and acute inflammatory processes. Furthermore this knowledge will improve desired complement activation by therapeutic antibodies and vaccination strategies in infectious diseases. Finally, this work opens up new possibilities to understand how both humans and bacteria regulate complement.

Meccanismo di finanziamento

ERC-STG - Starting Grant

Istituzione ospitante

UNIVERSITAIR MEDISCH CENTRUM UTRECHT
Contribution nette de l'UE
€ 1 497 290,00
Indirizzo
HEIDELBERGLAAN 100
3584 CX Utrecht
Paesi Bassi

Mostra sulla mappa

Regione
West-Nederland Utrecht Utrecht
Tipo di attività
Higher or Secondary Education Establishments
Collegamenti
Costo totale
€ 1 497 290,00

Beneficiari (1)