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Project 26
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Project 26

Hamid Kashkar

XIAP-mediated cell-autonomous immune reaction against Shigella flexneri

Institute for Medial Microbiology, Immunology and Hygiene, University of Cologne


Brief description in German
Dieses Projekt untersucht die Rolle von XIAP (X-linked inhibitor of apoptosis) in der zellautonomen Immunabwehr gegen Bakterien am Beispiel von Shigella flexneri. In den eigenen Vorarbeiten wurde gezeigt, dass die S. flexneri–induzierte zellautonome Immunreaktion (NF-κB-Aktivierung und Produktion von IL-8) durch XIAP vermittelt wrrd. Detaillierte Analysen, die die Regulation und Funktion von XIAP während einer S. flexneri-Infektion aufklären, werden wertvolle Erkenntnisse über die Physiologie intrazellulärer Infektionen liefern und zum besseren Verständnis von Immunität gegen infektiöse Erreger beitragen.

The X-linked inhibitor of apoptosis protein (XIAP) is a potent caspase inhibitor best known for its anti-apoptotic function in cancer. During apoptosis, XIAP is antagonized by SMAC, which is released from the mitochondria upon caspase-mediated activation of the BH3-only protein, BID.

Recent biochemical analyses showed that XIAP is also involved in immune inflammatory signaling. In line with these observations, XIAP-deficiency in humans is associated with X-linked lymphoproliferative disease (XLP) causing primary immunodeficiency and chronic hemorrhagic colitis.

In the last funding period we employed Shigella flexneri (S. flexneri), an invasive Gram-negative enteropathogenic bacterium, to analyze the impact of XIAP on cell-autonomous immune responses to enteroinvasive bacterial infection. Our data showed that XIAP is required for immune inflammatory signaling and immunity against S. flexneri both, in vitro and in vivo.

Many enteroinvasive bacterial pathogens including Shigella evolved strategies to actively down-regulate the cell-autonomous immediate immune responses that would be detrimental to the bacteria at early stages of infection. Our data show that in epithelial cells S. flexneri evades the XIAP-mediated immune response by usurping BID-mediated release of SMAC from mitochondria.

Unlike apoptotic stimuli, S. flexneri involves calpain-mediated cleavage of BID, which triggers the release of mitochondrial SMAC into the cytosol, where it antagonizes the inflammatory action of XIAP without inducing apoptosis. Our results demonstrate how cellular death machinery can be diverted by an enteroinvasive pathogen to ensure bacterial survival and replication in epithelial niche.

This project aims at three specific issues:

I) Recent data showed that XIAP interferes with inflammatory signaling based on its ubiquitin (Ub)-ligase activity. We will systematically investigate the role and the control of the ubiquitin conjugation by XIAP during the course of S. flexneri infection and immune reaction.

II) Our data showed that S. flexneri induces a non-apoptotic form of mitochondrial outer membrane permeabilization (MOMP), which triggers the release of mitochondrial SMAC, but not cytochrome c, and consequently antagonizes XIAP-mediated immune signaling but avoids caspase activity and cell death. We aim to identify the underlying molecular mechanism which is responsible for the non-apoptotic MOMP upon S. flexneri infection.

III) Unlike epithelial cells, macrophages die by Shigella infection representing an essential step in the pathogenesis of shigellosis. We will explore the role of XIAP and its antagonization by BID-mediated SMAC release in macrophage cell death and immune function in response to S. flexneri Infection.

A better understanding of these mechanisms could open novel therapeutic avenues against enteroinvasive bacterial infections.

List of relevant publications resulting from the project
Peer-reviewed publications:

Schüll S, Günther SD, Brodesser S, Seeger JM, Tosetti B, Wiegmann K, Pongratz C, Diaz F, Witt A, Andree M, Brinkmann K, Krönke M, Wiesner RJ, Kashkar H. Cytochrome c oxidase deficiency accelerates mitochondrial apoptosis by activating ceramide synthase 6. Cell Death Dis. 2015, 6:e1691

Witt A, Seeger JM, Coutelle O, Zigrino P, Broxtermann P, Andree M, Brinkmann K, Jüngst C, Schauss AC, Schüll S, Wohlleber D, Knolle P, Krönke M, Mauch C, Kashkar H. IAP antagonization induces inflammatory destruction of vascular endothelium. EMBO Rep. 2015, 16:719-727

Förster A, Grotha S, Seeger JM, Rabenhorst A, Gehring M, Raap U, Létard S, Dubreuil P, Kashkar H, Walczak H, Roers A, Hartmann K. Activation of KIT modulates the function of tumor necrosis factor-related apoptosis-inducing ligand receptor (TRAIL-R) in mast cells. Allergy 2015, 70:764-74

Andree M, Seeger JM, Schüll S, Coutelle O, Wagner-Stippich D, Wiegmann K, Wunderlich C, Brinkmann K, Broxtermann PN, Witt A., Fritsch M, Martinelli P, Bielig H, Lamkemeyer T, Rugarli EI, Kaufmann T, Sterner-Koch A, Wunderlich, FT, Villunger A, Martins LM, Krönke M, Kufer T, Utermöhlen O, Kashkar H. (2014) BID-mediated release of mitochondrial SMAC dampens XIAP-mediated immunity against Shigella. EMBO J. 2014, 33:2171-2187

Bielig H, Lautz K, Braun PR, Menning M, Machuy N, Brügmann C, Barisic S, Eisler SA, Andree M, Kashkar H, Zurek B, Hausser A, Sansonetti PJ, Meyer TF, Kufer TA. (2014) The cofilin phosphatase Slingshot Homolog 1 (SSH1) links NOD1 signalling to actin remodeling. PLoS pathogens, 10:e1004351

Coutelle O, Hornig-Do HT, Witt A, Andree M, Schiffmann LM, Liwschitz M, Seeger JM, Piekarek M, Brinkmann K, Hallek M, Krönke M, Trifunovic A, Eming SA, Wiesner RJ, Hacker UT and Kashkar H. (2014)  Embelin inhibits endothelial mitochondrial respiration and impairs neoangiogenesis during tumor growth and wound healing EMBO Mol. Med., 6:624-639

Förster A, Preussner LM, Seeger JM, Rabenhorst A, Kashkar H, Mrowietz U, Hartmann K. (2013) Dimethylfumarate induces apoptosis in human mast cells. Exp. Dermatol., 22:719-724

Förster A, Falcone FH, Gibbs BF, Preussner LM, Fiebig BS, Altunok H, Seeger JM, Cerny-Reiterer S, Rabenhors A, Papenfuss K, Valent P, Kashkar H, Hartmann K. (2013) Anti-Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) differentially regulate apoptosis in normal and neoplastic human basophils. Leuk Lymphoma, 54:835-42

Böcke A, Sieger D, Kashkar H, Krönke M. (2012) FAN mediates navigational capacity of macrophages responding to wounds and infection- live imaging studies in zebrafish larvae. J Immunol., 189:1559-66

Wohlleber D*, Kashkar H*, Gärtner K*, Frings MK, Odenthal M, Hegenbarth S, Börner C, Arnold B, Hämmerling G, Niesswandt B, van Rooijen N, Limmer A, Cederbrand K, Heikenwälder M, Pasparakis M, Protzer U, Dienes HP, Kurts C, Krönke M, and Knolle PA. (2012) TNF-Induced Target Cell Killing by CTL Activated through Cross-Presentation. Cell Rep., 2(3):478-487 *equal contribution

Hörnle M, Peters N, Thayaparasingham B, Vörsmann H, Kashkar H, and Kulms D. (2011) Caspase-3 cleaves XIAP in a positive feedback loop to sensitize melanoma cells to TRAIL-induced apoptosis. Oncogene, 30(5), 575–587.

Yazdanpanah, B., Wiegmann, K., Tchikov, V., Krut, O., Pongratz, C., Schramm, M., Kleinridders, A., Wunderlich, T., Kashkar, H., Utermöhlen, O., et al. (2009). Riboflavin kinase couples TNF receptor 1 to NADPH oxidase. Nature 460, 1159-1163.

Herz, J., Pardo, J., Kashkar, H., Schramm, M., Kuzmenkina, E., Bos, E., Wiegmann, K., Wallich, R., Peters, P.J., Herzig, S., et al. (2009). Acid sphingomyelinase is a key regulator of cytotoxic granule secretion by primary T lymphocytes. Nature Immunology 10, 761-768.

Meemboor, S., Mertens, J., Flenner, E., Groneck, L., Zingarelli, A., Gamstätter, T., Bessler, M., Seeger, J.M., Kashkar, H., Odenthal, M., Kalka-Moll, W.M. (2009). Interleukin 6 is essential for zwitterionic polysaccharide-mediated abscess formation. Innate Immunity, 16(5):310-21.

Mertens, J., Fabri, M., Zingarelli, A., Kubacki, T., Meemboor, S., Groneck, L., Seeger, J., Bessler, M., Hafke, H., Odenthal, M., Bieler, J.G., Kalka, C., Schneck, J.P., Kashkar, H., Kalka-Moll, W.M. (2009). Streptococcus pneumoniae serotype 1 capsular polysaccharide induces CD8CD28 regulatory T lymphocytes by TCR crosslinking. PLoS Pathogens 5, e1000596.

Schnaith, A., Kashkar, H., Leggio, S.A., Addicks, K., Krönke, M., and Krut, O. (2007). Staphylococcus aureus subvert autophagy for induction of caspase-independent host cell death. J Biol Chem 282, 2695-2706.

Abdullah, Z., Saric, T., Kashkar, H., Baschuk, N., Yazdanpanah, B., Fleischmann, B.K., Hescheler, J., Krönke, M., and Utermöhlen, O. (2007). Serpin-6 expression protects embryonic stem cells from lysis by antigen-specific CTL. J Immunol 178, 3390-3399.

Haubert, D., Gharib, N., Rivero, F., Wiegmann, K., Hösel, M., Krönke, M., and Kashkar, H. (2007). PtdIns(4,5)P-restricted plasma membrane localization of FAN is involved in TNF-induced actin reorganization. EMBO Journal 26, 3308-3321.

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