Biology subjects

Salvesen, G.

Publications and source records attributed to Salvesen, G..

3 recordsLinked to original sources

bioRxiv2020

Evolutionary loss of inflammasomes in carnivores to facilitate carriage of zoonotic infections

Zoonotic infections, such as COVID-19, reside in animal hosts before jumping species to humans. The Carnivora, like mink, carry many zoonoses yet how diversity in host immune genes across species impact upon pathogen carriage are poorly understood. Here we describe a progressive evolutionary downregulation of pathogen sensing inflammasome pathways in Carnivora. This includes the loss of nucleotide-oligomerisation domain leucine rich repeat receptors (NLRs), acquisition of a unique caspase-1/-4 effector fusion protein that processes gasdermin D pore formation without inducing lytic cell death and the formation of an NLRP3-caspase-8 containing inflammasome that inefficiently processes interleukin-1{beta} (IL-1{beta}). Inflammasomes regulate gut immunity, but the carnivorous diet is antimicrobial suggesting a tolerance to the loss of these immune pathways. The consequences of systemic inflammasome downregulation, however, can reduce the host sensing of specific pathogens such that they can reside undetected in the Carnivora.

immunology↗

bioRxiv2019

Noninvasive optical detection of Granzyme B from natural killer cells using enzyme-activated fluorogenic probes

Despite many studies on the cytotoxic protease granzyme B, key aspects of its function remain unexplored due to the lack of selective probes for its activity. In this study, we fully mapped the substrate preferences of GrB using a set of unnatural amino acids, demonstrating previously unknown GrB substrate preferences that we then used to design novel substrate-based inhibitors and a GrB-activatable activity-based probe. We showed that our GrB probes react poorly with caspases, making them ideal for the in-depth analysis of GrB localization and function in cells. With our quenched fluorescence substrate, we determined GrB within the cytotoxic granules of human YT cells. When used as cytotoxic effectors, YT cells loaded with the GrB attack MDA-MB-231 target cells, and active GrB influences its target cell killing efficiency.

biochemistry↗

bioRxiv2019

Detection of active Granzyme A in NK92 cells with fluorescent activity-based probe

Cytotoxic T-lymphocytes (CTLs) and natural killer cells (NKs) kill compromised cells to defend against tumor and viral infections. Both effector cell types use multiple strategies to induce target cell death including Fas/CD95 activation; and the release of perforin and a group of lymphocyte granule serine proteases called granzymes. Granzymes have relatively broad and overlapping substrate specificities and may hydrolyze a wide range of peptidic epitopes; it is therefore challenging to identify their natural and synthetic substrates and to distinguish their localization and functions. Here, we present a specific and potent substrate, an inhibitor, and an activity-based probe of Granzyme A (GrA) that can be used to follow functional GrA in cells.

biochemistry↗