@article{MuellerSienerthDietzHoltzetal.2011,
  author    = {M{\"u}ller-Sienerth, Nicole and Dietz, Lena and Holtz, Philipp and Kapp, Markus and Grigoleit, G{\"o}tz Ulrich and Schmuck, Carsten and Wajant, Harald and Siegmund, Siegmund},
  title     = {SMAC Mimetic BV6 Induces Cell Death in Monocytes and Maturation of Monocyte-Derived Dendritic Cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76106},
  year      = {2011},
  abstract  = {Background: Compounds mimicking the inhibitory effect of SMAC / DIABLO on X-linked inhibitor of apoptosis (XIAP) have been developed with the aim to achieve sensitization for apoptosis of tumor cells resistant due to deregulated XIAP expression. It turned out that SMAC mimetics also have complex effects on the NFkB system and TNF signaling. In view of the overwhelming importance of the NFkB transcription factors in the immune system, we analyzed here the effects of the SMAC mimetic BV6 on immune cells. Principal Findings: BV6 induced apoptotic and necrotic cell death in monocytes while T-cells, dendritic cells and macrophages were largely protected against BV6-induced cell death. In immature dendritic cells BV6 treatment resulted in moderate activation of the classical NFkB pathway, but it also diminished the stronger NFkB-inducing effect of TNF and CD40L. Despite its inhibitory effect on TNF- and CD40L signaling, BV6 was able to trigger maturation of immature DCs as indicated by upregulation of CD83, CD86 and IL12. Significance: The demonstrated effects of SMAC mimetics on immune cells may complicate the development of tumor therapeutic concepts based on these compounds but also arise the possibility to exploit them for the development of immune stimulatory therapies.},
  subject      = {Medizin},
  language  = {en}
}
@phdthesis{Siegmund2018,
  author    = {Siegmund, Constanze},
  title     = {Klinische Bedeutung der Regulation von L-Arginin sowie deren Derivate SDMA und ADMA im Akuten Nierenversagen - eine prospektive monozentrische Kohortenstudie (CASA-AKI Studie)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164300},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {Zusammenfassung Die vorliegende Arbeit untersucht die Regulation von SDMA/ADMA sowie L-Arginin im akuten Nierenversagen beim Menschen. Da SDMA ausschließlich renal eliminiert wird, ist der Fragestellung nachgegangen worden, ob SDMA als Marker der renalen Funktion herangezogen werden k{\"o}nnte. Des Weiteren wurde gepr{\"u}ft ob ein Zusammenhang von SDMA/ ADMA und L-Arginin mit der Mortalit{\"a}t besteht. Die Derivate von L-Arginin, Symmetrisches und asymmetrischen Dimethylarginin (SDMA/ ADMA) vermindern die NO Verf{\"u}gbarkeit, außerdem ist NO an der Gef{\"a}ßrelaxation beteiligt, dessen Abwesenheit f{\"o}rdert die Pl{\"a}ttchenaggregation und Inflammation. So k{\"o}nnte ein NO-Mangel {\"u}ber einen Anstieg von ADMA und SDMA eine endotheliale Dysfunktion bewirken und somit im akuten Nierenversagen das Mortalit{\"a}tsrisiko steigern. Die Hypothese war, dass SDMA analog zum chronischen Nierenversagen ein endogener Marker der renalen Funktion ist und gegebenenfalls Risikomarker f{\"u}r eine erh{\"o}hte Mortalit{\"a}t sein k{\"o}nnte. Hierf{\"u}r wurden Patienten mit der Diagnose „Akutes Nierenversagen" rekrutiert. Bei diesen wurde zu zwei Zeitpunkten Blutproben gewonnen. Die erste Blutentnahme erfolgte im akuten Nierenversagen. Eine zweite Blutentnahme zur Re-evaluation erfolgte wenn sich laborchemisch eine Besserung des Nierenversagens zeigte (Abfall des Serum-Creatinins >0.3mg/dl). Zudem wurden die Patienten 6 Monate nach Entlassung nochmals kontaktiert um das Gesamt{\"u}berleben zu ermitteln. L-Arginin und die Dimethylarginine wurden mit Nierenfunktionsparametern sowie weiteren Laborwerten, demographischen Daten sowie der Mortalit{\"a}t assoziiert. 120 Patienten (Durchschnittsalter 65±18 Jahre) mit der Diagnose eines akuten Nieren-versagens wurden in die Studie eingeschlossen. Definitionsgem{\"a}ß waren zum Zeitpunkt der ersten Messung s{\"a}mtliche Nierenretentionsparameter erh{\"o}ht: Serum-Creatinin lag bei 3.1 mg/dl (2.13-4.18). Der mediane L-Arginin-Serumwert lag mit 71.85 (53-104) μmol/l leicht unter dem Referenzwert, der f{\"u}r eine nierengesunde Population definiert ist (77.4 (59.2 - 95.6) μmol/l). Der durchschnittliche ADMA-Serumwert lag mit 0.65±0.19 μmol/l leicht {\"u}ber dem Referenzwert (0.53±0.12 (0.41-0.65) μmol/l). SDMA-Serumwerte waren mit 1.8 (1.34-2.29) μmol/l deutlich erh{\"o}ht (Normalwerte: 0.225-0.533 μmol/l). Bei Studieneinschluss korrelierte Serum SDMA deutlich mit den Nierenfunktionsparametern Creatinin, Harnstoff und Harns{\"a}ure. Dies unterst{\"u}tzt die Hypothese, dass SDMA auch im akuten Nierenversagen ein Marker der renalen Funktion ist. Die positive Korrelation mit CRP, LDH und inversem Albumin mit SDMA zeigt dessen zus{\"a}tzliche Funktion als Indikator f{\"u}r den Schweregrad einer septischen Erkrankung. Außerdem korrelierte SDMA positiv mit der Mortalit{\"a}t. 70 Personen erf{\"u}llten die Kriterien einer Erholung der Nierenfunktion und konnten f{\"u}r eine Zweitmessung (t2) eingeschlossen werden. Im Vergleich zu t1 sank Serum-Creatinin bei t2 um mehr als die H{\"a}lfte (3.7 mg/dl (Zeitpunkt t1) auf 1.7 mg/dl (Zeitpunkt t2)). L-Arginin-Werte blieben unver{\"a}ndert, w{\"a}hrend SDMA deutlich (35\%) und ADMA-Spiegel leicht (10\%) signifikant fielen. Analog zum Zeitpunkt t1, zeigte sich auch in der Zweitmessung eine ausgepr{\"a}gte positive Korrelation von SDMA (t2) und Creatinin (t2). Außerdem zeigte SDMA 2 eine signifikante Korrelation mit dem Alter, mit anderen Vorerkrankungen (Hypertonie, chronische Niereninsuffizienz) sowie mit der Mortalit{\"a}t. Letzteres deutet auf eine potentielle prognostische Relevanz hin und wurde eingehender untersucht. Hierf{\"u}r wurden die Studienteilnehmer in die Untergruppen der {\"U}berlebenden und Nicht-{\"U}berlebenden eingeteilt. Follow-up Informationen konnten von 118 Patienten erhoben werden. Von diesen waren insgesamt 17\% (n=20) innerhalb des Beobachtungszeitraumes verstorben. Die verstorbenen Patienten waren im Durchschnitt mit 76.8 Jahren signifikant {\"a}lter als die {\"u}brigen Patienten (63.7 Jahre) und h{\"a}ufiger an Hypertonus, CKD und Diabetes mellitus erkrankt. Zudem zeigte sich bei diesen Patienten SDMA zum Zeitpunkt t2 mit 1.84 μmol/l um ein Drittel signifikant h{\"o}her, als bei den {\"U}berlebenden (1.21 μmol/l). L-Arginin war mit 66.7 μmol/l um ca. 30\% niedriger, als bei Patienten, die das ANV {\"u}berlebten (92.4 μmol/l). Somit war auch die L-Arginin/ SDMA Ratio (t2) signifikant erniedrigt, was durch das inhibitorische Potential von SDMA eine geringere intrazellul{\"a}re L-Arginin Verf{\"u}gbarkeit und damit eine verminderte Produktion von NO bedingen k{\"o}nnte. Dies k{\"o}nnte einen pathophysiologischen Mechanismus darstellen. In univariaten Cox-Regressionsanalysen zeigte sich, dass SDMA (t1), SDMA (t2) und L-Arginin/SDMA Ratio (t2) sowie das Alter und die L{\"a}nge der Hospitalisationsdauer mit einer erh{\"o}hten Mortalit{\"a}t assoziiert waren. Außerdem korrelierten Begleiterkrankungen, wie Hypertonus, Diabetes mellitus und chronische Niereninsuffizienz (CKD) mit der Mortalit{\"a}t. Weiterhin zeigte sich, dass SDMA 1 ein unabh{\"a}ngiger mit der Mortalit{\"a}t korrelierender Parameter war, f{\"u}r den ein prognostischer Grenzwert existiert. Bei Patienten mit einem Serum-SDMA-Spiegel (t1) {\"u}ber 2.26 μmol/l war das kumulative {\"U}berleben signifikant vermindert im Vergleich zu Patienten mit einem Serumspiegel unter diesem SDMA cut-off-Wert. Die vorliegende Arbeit zeigt erstmals einen Zusammenhang zwischen der H{\"o}he des Serum-SDMA-Spiegels und dem Ausmaß der renaler Funktionseinschr{\"a}nkung sowie der {\"U}berlebenswahrscheinlichkeit bei Patienten mit akutem Nierenversagen. Aufgrund der guten Korrelation mit den Creatinin-Serum-Spiegeln scheint Serum-SDMA auch im akuten Nierenversagen ein ad{\"a}quater endogener Marker der renalen Funktion zu sein. Zus{\"a}tzlich durch die unabh{\"a}ngige Assoziation mit der Mortalit{\"a}t im follow-up sowie seiner Assoziation mit prognostisch relevanten nicht-renalen Laborparametern, wie Albumin und CRP k{\"o}nnte Serum-SDMA in Zukunft im klinischen Alltag zur Risikostratifizierung von Patienten im akuten Nierenversagen beitragen.},
  subject      = {Arginin},
  language  = {de}
}
@article{MuellerSienerthDietzHoltzetal.2011,
  author    = {M{\"u}ller-Sienerth, Nicole and Dietz, Lena and Holtz, Philipp and Kapp, Markus and Grigoleit, G{\"o}tz Ulrich and Schmuck, Carsten and Wajant, Harald and Siegmund, Daniela},
  title     = {SMAC Mimetic BV6 Induces Cell Death in Monocytes and Maturation of Monocyte-Derived Dendritic Cells},
  series = {PLoS ONE},
  volume    = {6},
  journal   = {PLoS ONE},
  number    = {6},
  doi       = {10.1371/journal.pone.0021556},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-142415},
  pages     = {e21556},
  year      = {2011},
  abstract  = {Background: Compounds mimicking the inhibitory effect of SMAC / DIABLO on X-linked inhibitor of apoptosis (XIAP) have been developed with the aim to achieve sensitization for apoptosis of tumor cells resistant due to deregulated XIAP expression. It turned out that SMAC mimetics also have complex effects on the NF kappa B system and TNF signaling. In view of the overwhelming importance of the NF kappa B transcription factors in the immune system, we analyzed here the effects of the SMAC mimetic BV6 on immune cells. Principal Findings: BV6 induced apoptotic and necrotic cell death in monocytes while T-cells, dendritic cells and macrophages were largely protected against BV6-induced cell death. In immature dendritic cells BV6 treatment resulted in moderate activation of the classical NF kappa B pathway, but it also diminished the stronger NF kappa B-inducing effect of TNF and CD40L. Despite its inhibitory effect on TNF- and CD40L signaling, BV6 was able to trigger maturation of immature DCs as indicated by upregulation of CD83, CD86 and IL12. Significance: The demonstrated effects of SMAC mimetics on immune cells may complicate the development of tumor therapeutic concepts based on these compounds but also arise the possibility to exploit them for the development of immune stimulatory therapies.},
  language  = {en}
}
@article{RauertStuehmerBargouetal.2011,
  author    = {Rauert, H. and St{\"u}hmer, T. and Bargou, R. and Wajant, H. and Siegmund, D.},
  title     = {TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76092},
  year      = {2011},
  abstract  = {The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival.},
  subject      = {Medizin},
  language  = {en}
}
@article{CarmonaAranaSeherNeumannetal.2014,
  author    = {Carmona Arana, Jos{\´e} Antonio and Seher, Axel and Neumann, Manfred and Lang, Isabell and Siegmund, Daniela and Wajant, Harald},
  title     = {TNF Receptor-Associated Factor 1 is a Major Target of Soluble TWEAK},
  series = {Frontiers in Immunology},
  volume    = {5},
  journal   = {Frontiers in Immunology},
  number    = {63},
  issn      = {1664-3224},
  doi       = {10.3389/fimmu.2014.00063},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120620},
  year      = {2014},
  abstract  = {Soluble tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), in contrast to membrane TWEAK and TNF, is only a weak activator of the classical NFκB pathway. We observed that soluble TWEAK was regularly more potent than TNF with respect to the induction of TNF receptor-associated factor 1 (TRAF1), a NFκB-controlled signaling protein involved in the regulation of inflammatory signaling pathways. TNF-induced TRAF1 expression was efficiently blocked by inhibition of the classical NFκB pathway using the IKK2 inhibitor, TPCA1. In contrast, in some cell lines, TWEAK-induced TRAF1 production was only partly inhibited by TPCA1. The NEDD8-activating enzyme inhibitor MLN4924, however, which inhibits classical and alternative NFκB signaling, blocked TNF- and TWEAK-induced TRAF1 expression. This suggests that TRAF1 induction by soluble TWEAK is based on the cooperative activity of the two NFκB signaling pathways. We have previously shown that oligomerization of soluble TWEAK results in ligand complexes with membrane TWEAK-like activity. Oligomerization of soluble TWEAK showed no effect on the dose response of TRAF1 induction, but potentiated the ability of soluble TWEAK to trigger production of the classical NFκB-regulated cytokine IL8. Transfectants expressing soluble TWEAK and membrane TWEAK showed similar induction of TRAF1 while only the membrane TWEAK expressing cells robustly stimulated IL8 production. These data indicate that soluble TWEAK may efficiently induce a distinct subset of the membrane TWEAK-targeted genes and argue again for a crucial role of classical NFκB pathway-independent signaling in TWEAK-induced TRAF1 expression. Other TWEAK targets, which can be equally well induced by soluble and membrane TWEAK, remain to be identified and the relevance of the ability of soluble TWEAK to induce such a distinct subset of membrane TWEAK-targeted genes for TWEAK biology will have to be clarified in future studies.},
  language  = {en}
}
@article{TrebingElMeserySchaeferetal.2014,
  author    = {Trebing, J. and El-Mesery, M. and Sch{\"a}fer, V. and Weisenberger, D. and Siegmund, D. and Silence, K. and Wajant, H.},
  title     = {CD70-restricted specific activation of TRAILR1 or TRAILR2 using scFv-targeted TRAIL mutants},
  series = {Cell Death \& Disease},
  volume    = {5},
  journal   = {Cell Death \& Disease},
  doi       = {10.1038/cddis.2013.555},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120078},
  pages     = {e1035},
  year      = {2014},
  abstract  = {To combine the CD27 stimulation inhibitory effect of blocking CD70 antibodies with an antibody-dependent cellular cytotoxicity (ADCC)-independent, cell death-inducing activity for targeting of CD70-expressing tumors, we evaluated here fusion proteins of the apoptosis-inducing TNF family member TRAIL and a single-chain variable fragment (scFv) derived from a high-affinity llama-derived anti-human CD70 antibody (lαhCD70). A fusion protein of scFv:lαhCD70 with TNC-TRAIL, a stabilized form of TRAIL, showed strongly enhanced apoptosis induction upon CD70 binding and furthermore efficiently interfered with CD70-CD27 interaction. Noteworthy, introduction of recently identified mutations that discriminate between TRAILR1 and TRAILR2 binding into the TRAIL part of scFv:lαhCD70-TNC-TRAIL resulted in TRAIL death receptor-specific fusion proteins with CD70-restricted activity.},
  language  = {en}
}
@article{HoyerSchatzschneiderSchulzSiegmundetal.2012,
  author    = {Hoyer, Jan and Schatzschneider, Ulrich and Schulz-Siegmund, Michaela and Neundorf, Ines},
  title     = {Dimerization of a cell-penetrating peptide leads to enhanced cellular uptake and drug delivery},
  series = {Beilstein Journal of Organic Chemistry},
  volume    = {8},
  journal   = {Beilstein Journal of Organic Chemistry},
  doi       = {10.3762/bjoc.8.204},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133933},
  pages     = {1788-1797},
  year      = {2012},
  abstract  = {Over the past 20 years, cell-penetrating peptides (CPPs) have gained tremendous interest due to their ability to deliver a variety of therapeutically active molecules that would otherwise be unable to cross the cellular membrane due to their size or hydrophilicity. Recently, we reported on the identification of a novel CPP, sC18, which is derived from the C-terminus of the 18 kDa cationic antimicrobial protein. Furthermore, we demonstrated successful application of sC18 for the delivery of functionalized cyclopentadienyl manganese tricarbonyl (cymantrene) complexes to tumor cell lines, inducing high cellular toxicity. In order to increase the potential of the organometallic complexes to kill tumor cells, we were looking for a way to enhance cellular uptake. Therefore, we designed a branched dimeric variant of sC18, (sC18)\(_2\), which was shown to have a dramatically improved capacity to internalize into various cell lines, even primary cells, using flow cytometry and fluorescence microscopy. Cell viability assays indicated increased cytotoxicity of the dimer presumably caused by membrane leakage; however, this effect turned out to be dependent on the specific cell type. Finally, we could show that conjugation of a functionalized cymantrene with (sC18)\(_2\) leads to significant reduction of its IC\(_{50}\) value in tumor cells compared to the respective sC18 conjugate, proving that dimerization is a useful method to increase the drug-delivery potential of a cell-penetrating peptide.},
  language  = {en}
}
@article{RauertStuehmerBargouetal.2011,
  author    = {Rauert, H. and St{\"u}hmer, T. and Bargou, R. and Wajant, H. and Siegmund, D.},
  title     = {TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms},
  series = {Cell Death and Disease},
  volume    = {2},
  journal   = {Cell Death and Disease},
  doi       = {10.1038/cddis.2011.78},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133486},
  pages     = {e194},
  year      = {2011},
  abstract  = {The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival},
  language  = {en}
}
@article{RauertWunderlichSiegmundMaieretal.2013,
  author    = {Rauert-Wunderlich, Hilka and Siegmund, Daniela and Maier, Eduard and Giner, Tina and Bargou, Ralf C. and Wajant, Harald and St{\"u}hmer, Thorsten},
  title     = {The IKK Inhibitor Bay 11-7082 Induces Cell Death Independent from Inhibition of Activation of NF kappa B Transcription Factors},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {3},
  doi       = {10.1371/journal.pone.0059292},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130140},
  pages     = {e59292},
  year      = {2013},
  abstract  = {Multiple myeloma (MM) displays an NFκB activity-related gene expression signature and about 20\% of primary MM samples harbor genetic alterations conducive to intrinsic NFκB signaling activation. The relevance of blocking the classical versus the alternative NFκB signaling pathway and the molecular execution mechanisms involved, however, are still poorly understood. Here, we comparatively tested NFκB activity abrogation through TPCA-1 (an IKK2 inhibitor), BAY 11-7082 (an IKK inhibitor poorly selective for IKK1 and IKK2), and MLN4924 (an NEDD8 activating enzyme (NAE)-inhibitor), and analyzed their anti-MM activity. Whereas TPCA-1 interfered selectively with activation of the classical NFκB pathway, the other two compounds inhibited classical and alternative NFκB signaling without significant discrimination. Noteworthy, whereas TPCA-1 and MLN4924 elicited rather mild anti-MM effects with slight to moderate cell death induction after 1 day BAY 11-7082 was uniformly highly toxic to MM cell lines and primary MM cells. Treatment with BAY 11-7082 induced rapid cell swelling and its initial effects were blocked by necrostatin-1 or the ROS scavenger BHA, but a lasting protective effect was not achieved even with additional blockade of caspases. Because MLN4924 inhibits the alternative NFκB pathway downstream of IKK1 at the level of p100 processing, the quite discordant effects between MLN4924 and BAY 11-7082 must thus be due to blockade of IKK1-mediated NFκB-independent necrosis-inhibitory functions or represent an off-target effect of BAY 11-7082. In accordance with the latter, we further observed that concomitant knockdown of IKK1 and IKK2 did not have any major short-term adverse effect on the viability of MM cells.},
  language  = {en}
}
@article{ElMeseryTrebingSchaferetal.2013,
  author    = {El-Mesery, M. and Trebing, J. and Schafer, V. and Weisenberger, D. and Siegmund, D. and Wajant, H.},
  title     = {CD40-directed scFv-TRAIL fusion proteins induce CD40-restricted tumor cell death and activate dendritic cells},
  series = {Cell Death \& Disease},
  volume    = {4},
  journal   = {Cell Death \& Disease},
  number    = {e916},
  doi       = {10.1038/cddis.2013.402},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128777},
  year      = {2013},
  abstract  = {Targeted cancer therapy concepts often aim at the induction of adjuvant antitumor immunity or stimulation of tumor cell apoptosis. There is further evidence that combined application of immune stimulating and tumor apoptosis-inducing compounds elicits a synergistic antitumor effect. Here, we describe the development and characterization of bifunctional fusion proteins consisting of a single-chain variable fragment (scFv) domain derived from the CD40-specific monoclonal antibody G28-5 that is fused to the N-terminus of stabilized trimeric soluble variants of the death ligand TNF-related apoptosis-inducing ligand (TRAIL). As shown before by us and others for other cell surface antigen-targeted scFv-TRAIL fusion proteins, scFv:G28-TRAIL displayed an enhanced capacity to induce apoptosis upon CD40 binding. Studies with scFv:G28 fusion proteins of TRAIL mutants that discriminate between the two TRAIL death receptors, TRAILR1 and TRAILR2, further revealed that the CD40 binding-dependent mode of apoptosis induction of scFv:G28-TRAIL is operable with each of the two TRAIL death receptors. Binding of scFv:G28-TRAIL fusion proteins to CD40 not only result in enhanced TRAIL death receptor signaling but also in activation of the targeted CD40 molecule. In accordance with the latter, the scFv:G28-TRAIL fusion proteins triggered strong CD40-mediated maturation of dendritic cells. The CD40-targeted TRAIL fusion proteins described in this study therefore represent a novel type of bifunctional fusion proteins that couple stimulation of antigen presenting cells and apoptosis induction.},
  language  = {en}
}
@article{BrunekreeftStrohmGoodenetal.2014,
  author    = {Brunekreeft, Kim L. and Strohm, Corinna and Gooden, Marloes J. and Rybczynska, Anna A. and Nijman, Hans W. and Grigoleit, G{\"o}tz U. and Helfrich, Wijnand and Bremer, Edwin and Siegmund, Daniela and Wajant, Harald and de Bruyn, Marco},
  title     = {Targeted delivery of CD40L promotes restricted activation of antigen-presenting cells and induction of cancer cell death},
  series = {Molecular Cancer},
  volume    = {13},
  journal   = {Molecular Cancer},
  number    = {85},
  issn      = {1476-4598},
  doi       = {10.1186/1476-4598-13-85},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116682},
  year      = {2014},
  abstract  = {Background: Stimulation of CD40 can augment anti-cancer T cell immune responses by triggering effective activation and maturation of antigen-presenting cells (APCs). Although CD40 agonists have clinical activity in humans, the associated systemic activation of the immune system triggers dose-limiting side-effects. Methods: To increase the tumor selectivity of CD40 agonist-based therapies, we developed an approach in which soluble trimeric CD40L (sCD40L) is genetically fused to tumor targeting antibody fragments, yielding scFv: CD40L fusion proteins. We hypothesized that scFv: CD40L fusion proteins would have reduced CD40 agonist activity similar to sCD40L but will be converted to a highly agonistic membrane CD40L-like form of CD40L upon anchoring to cell surface exposed antigen via the scFv domain. Results: Targeted delivery of CD40L to the carcinoma marker EpCAM on carcinoma cells induced dose-dependent paracrine maturation of DCs similar to 20-fold more effective than a non-targeted control scFv: CD40L fusion protein. Similarly, targeted delivery of CD40L to the B cell leukemia marker CD20 induced effective paracrine maturation of DCs. Of note, the CD20-selective delivery of CD40L also triggered loss of cell viability in certain B cell leukemic cell lines as a result of CD20-induced apoptosis. Conclusions: Targeted delivery of CD40L to cancer cells is a promising strategy that may help to trigger cancer-localized activation of CD40 and can be modified to exert additional anti-cancer activity via the targeting domain.},
  language  = {en}
}
@phdthesis{Siegmund2004,
  author    = {Siegmund, Inken},
  title     = {Anatomischer Vergleich von Ratte und Meerschweinchen zur Eignung f{\"u}r die experimentelle Kehlkopftransplantation},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9688},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Auf der Suche nach dem am besten geeigneten und praktikabelsten Tiermodell zur Erforschung unbeantworteter Fragen der Kehlkopftransplantation beim Menschen werden in der vorliegenden Arbeit verschiedene Tiermodelle der letzten 40 Jahre anhand der publizierten Daten mit ihren Vor- und Nachteilen vorgestellt und insbesondere die Frage behandelt, ob das Meerschweinchen in der Verwendung f{\"u}r die experimentelle Kehlkopftransplantation Vorteile gegen{\"u}ber der im Tiermodell bereits umfangreich erprobten Ratte bietet. Es wurden bei jeweils 10 Ratten und 10 Meerschweinchen Strukturen im kehlkopfnahen Halsbereich im Gr{\"o}ßenvergleich und unter Ber{\"u}cksichtigung topographischer Besonderheiten anatomisch untersucht, sowie die Vor- und Nachteile bez{\"u}glich ihrer Eignung f{\"u}r ein Tiermodell gegen{\"u}bergestellt. Im Ergebnisvergleich erweist sich das Rattenmodell einem Meerschweinchenmodell {\"u}berlegen. Den deutlichen Vorteilen der Ratte hinsichtlich Beschaffungskosten, g{\"u}nstigeren Zuchtbedingungen und geringerem postoperativem Pflegeaufwand, stehen die nur geringen k{\"o}rpervolumenbedingten Vorteile des Meerschweinchens bez{\"u}glich der Strukturgr{\"o}ßen gegen{\"u}ber, ohne dass dadurch ein Nutzen im Tiermodell gezogen werden kann. Die Ratte bleibt unter Ber{\"u}cksichtigung aller Untersuchungsergebnisse das Versuchstier erster Wahl f{\"u}r die experimentelle Kehlkopftransplantation und mikrogef{\"a}ßchirurgische {\"U}bungen.},
  language  = {de}
}
@article{RitterZimmermannJoehrensetal.2018,
  author    = {Ritter, Julia and Zimmermann, Karin and J{\"o}hrens, Korinna and Mende, Stefanie and Seegebarth, Anke and Siegmund, Britta and Hennig, Steffen and Todorova, Kremena and Rosenwald, Andreas and Daum, Severin and Hummel, Michael and Schumann, Michael},
  title     = {T-cell repertoires in refractory coeliac disease},
  series = {Gut},
  volume    = {67},
  journal   = {Gut},
  number    = {4},
  doi       = {10.1136/gutjnl-2016-311816},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226350},
  pages     = {644-653},
  year      = {2018},
  abstract  = {Objective Refractory coeliac disease (RCD) is a potentially hazardous complication of coeliac disease (CD). In contrast to RCD type I, RCD type II is a precursor entity of enteropathy-associated T-cell lymphoma (EATL), which is associated with clonally expanding T-cells that are also found in the sequentially developing EATL. Using high-throughput sequencing (HTS), we aimed to establish the small-intestinal T-cell repertoire (TCR) in CD and RCD to unravel the role of distinct T-cell clonotypes in RCD pathogenesis. Design DNA extracted from duodenal mucosa specimens of controls (n=9), active coeliacs (n=10), coeliacs on a gluten-free diet (n=9), RCD type I (n= 8), RCD type II (n= 8) and unclassified Marsh I cases (n= 3) collected from 2002 to 2013 was examined by TCR beta-complementarity- determining regions 3 (CDR3) multiplex PCR followed by HTS of the amplicons. Results On average, 106 sequence reads per sample were generated consisting of up to 900 individual TCR beta rearrangements. In RCD type II, the most frequent clonotypes (ie, sequence reads with identical CDR3) represent in average 42.6\% of all TCR beta rearrangements, which was significantly higher than in controls (6.8\%; p<0.01) or RCD type I (6.7\%; p<0.01). Repeat endoscopies in individual patients revealed stability of clonotypes for up to several years without clinical symptoms of EATL. Dominant clonotypes identified in individual patients with RCD type II were unique and not related between patients. CD-associated, gliad-independent CDR3 motifs were only detectable at low frequencies. Conclusions TCR beta-HTS analysis unravels the TCR in CD and allows detailed analysis of individual TCR beta rearrangements. Dominant TCR beta sequences identified in patients with RCD type II are unique and not homologous to known gliadin-specific TCR sequences, supporting the assumption that these clonal T-cells expand independent of gluten stimulation.},
  language  = {en}
}
@article{WuReimannSiddiquietal.2019,
  author    = {Wu, Hao and Reimann, Sabine and Siddiqui, Sophiya and Haag, Rainer and Siegmund, Britta and Dernedde, Jens and Glauben, Rainer},
  title     = {dPGS Regulates the Phenotype of Macrophages via Metabolic Switching},
  series = {Macromolecular Bioscience},
  volume    = {19},
  journal   = {Macromolecular Bioscience},
  number    = {12},
  doi       = {10.1002/mabi.201900184},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212711},
  year      = {2019},
  abstract  = {The synthetic compound dendritic polyglycerol sulfate (dPGS) is a pleiotropic acting molecule but shows a high binding affinity to immunological active molecules as L-/P-selectin or complement proteins leading to well described anti-inflammatory properties in various mouse models. In order to make a comprehensive evaluation of the direct effect on the innate immune system, macrophage polarization is analyzed in the presence of dPGS on a phenotypic but also metabolic level. dPGS administered macrophages show a significant increase of MCP1 production paralleled by a reduction of IL-10 secretion. Metabolic analysis reveals that dPGS could potently enhance the glycolysis and mitochondrial respiration in M0 macrophages as well as decrease the mitochondrial respiration of M2 macrophages. In summary the data indicate that dPGS polarizes macrophages into a pro-inflammatory phenotype in a metabolic pathway-dependent manner.},
  language  = {en}
}
@article{HerrmannHildebrandMenzeletal.2019,
  author    = {Herrmann, Marietta and Hildebrand, Maria and Menzel, Ursula and Fahy, Niamh and Alini, Mauro and Lang, Siegmund and Benneker, Lorin and Verrier, Sophie and Stoddart, Martin J. and Bara, Jennifer J.},
  title     = {Phenotypic characterization of bone marrow mononuclear cells and derived stromal cell populations from human iliac crest, vertebral body and femoral head},
  series = {International Journal of Molecular Sciences},
  volume    = {20},
  journal   = {International Journal of Molecular Sciences},
  number    = {14},
  issn      = {1422-0067},
  doi       = {10.3390/ijms20143454},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285054},
  year      = {2019},
  abstract  = {(1) In vitro, bone marrow-derived stromal cells (BMSCs) demonstrate inter-donor phenotypic variability, which presents challenges for the development of regenerative therapies. Here, we investigated whether the frequency of putative BMSC sub-populations within the freshly isolated mononuclear cell fraction of bone marrow is phenotypically predictive for the in vitro derived stromal cell culture. (2) Vertebral body, iliac crest, and femoral head bone marrow were acquired from 33 patients (10 female and 23 male, age range 14-91). BMSC sub-populations were identified within freshly isolated mononuclear cell fractions based on cell-surface marker profiles. Stromal cells were expanded in monolayer on tissue culture plastic. Phenotypic assessment of in vitro derived cell cultures was performed by examining growth kinetics, chondrogenic, osteogenic, and adipogenic differentiation. (3) Gender, donor age, and anatomical site were neither predictive for the total yield nor the population doubling time of in vitro derived BMSC cultures. The abundance of freshly isolated progenitor sub-populations (CD45-CD34-CD73+, CD45-CD34-CD146+, NG2+CD146+) was not phenotypically predictive of derived stromal cell cultures in terms of growth kinetics nor plasticity. BMSCs derived from iliac crest and vertebral body bone marrow were more responsive to chondrogenic induction, forming superior cartilaginous tissue in vitro, compared to those isolated from femoral head. (4) The identification of discrete progenitor populations in bone marrow by current cell-surface marker profiling is not predictive for subsequently derived in vitro BMSC cultures. Overall, the iliac crest and the vertebral body offer a more reliable tissue source of stromal progenitor cells for cartilage repair strategies compared to femoral head.},
  language  = {en}
}
@article{PradaMaagSiegmundetal.2022,
  author    = {Prada, Juan Pablo and Maag, Luca Estelle and Siegmund, Laura and Bencurova, Elena and Liang, Chunguang and Koutsilieri, Eleni and Dandekar, Thomas and Scheller, Carsten},
  title     = {Estimation of R0 for the spread of SARS-CoV-2 in Germany from excess mortality},
  series = {Scientific Reports},
  volume    = {12},
  journal   = {Scientific Reports},
  number    = {1},
  doi       = {10.1038/s41598-022-22101-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301415},
  year      = {2022},
  abstract  = {For SARS-CoV-2, R0 calculations in the range of 2-3 dominate the literature, but much higher estimates have also been published. Because capacity for RT-PCR testing increased greatly in the early phase of the Covid-19 pandemic, R0 determinations based on these incidence values are subject to strong bias. We propose to use Covid-19-induced excess mortality to determine R0 regardless of RT-PCR testing capacity. We used data from the Robert Koch Institute (RKI) on the incidence of Covid cases, Covid-related deaths, number of RT-PCR tests performed, and excess mortality calculated from data from the Federal Statistical Office in Germany. We determined R0 using exponential growth estimates with a serial interval of 4.7 days. We used only datasets that were not yet under the influence of policy measures (e.g., lockdowns or school closures). The uncorrected R0 value for the spread of SARS-CoV-2 based on RT-PCR incidence data was 2.56 (95\% CI 2.52-2.60) for Covid-19 cases and 2.03 (95\% CI 1.96-2.10) for Covid-19-related deaths. However, because the number of RT-PCR tests increased by a growth factor of 1.381 during the same period, these R0 values must be corrected accordingly (R0corrected = R0uncorrected/1.381), yielding 1.86 for Covid-19 cases and 1.47 for Covid-19 deaths. The R0 value based on excess deaths was calculated to be 1.34 (95\% CI 1.32-1.37). A sine-function-based adjustment for seasonal effects of 40\% corresponds to a maximum value of R0January = 1.68 and a minimum value of R0July = 1.01. Our calculations show an R0 that is much lower than previously thought. This relatively low range of R0 fits very well with the observed seasonal pattern of infection across Europe in 2020 and 2021, including the emergence of more contagious escape variants such as delta or omicron. In general, our study shows that excess mortality can be used as a reliable surrogate to determine the R0 in pandemic situations.},
  language  = {en}
}
@article{SiegmundKumsEhrenschwenderetal.2016,
  author    = {Siegmund, Daniela and Kums, Juliane and Ehrenschwender, Martin and Wajant, Harald},
  title     = {Activation of TNFR2 sensitizes macrophages for TNFR1-mediated necroptosis},
  series = {Cell Death \& Disease},
  volume    = {7},
  journal   = {Cell Death \& Disease},
  doi       = {10.1038/cddis.2016.285},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162317},
  pages     = {e2375},
  year      = {2016},
  abstract  = {Macrophages express TNFR1 as well as TNFR2 and are also major producers of tumor necrosis factor (TNF), especially upon contact with pathogen-associated molecular patterns. Consequently, TNF not only acts as a macrophage-derived effector molecule but also regulates the activity and viability of macrophages. Here, we investigated the individual contribution of TNFR1 and TNFR2 to TNF-induced cell death in macrophages. Exclusive stimulation of TNFR1 showed no cytotoxic effect whereas selective stimulation of TNFR2 displayed mild cytotoxicity. Intriguingly, the latter was strongly enhanced by the caspase inhibitor zVAD-fmk. The strong cytotoxic activity of TNFR2 in the presence of zVAD-fmk was reversed by necrostatin-1, indicating necroptotic cell death. TNFR1- and TNF-deficient macrophages turned out to be resistant against TNFR2-induced cell death. In addition, the cIAP-depleting SMAC mimetic BV6 also enforced TNF/TNFR1-mediated necroptotic cell death in the presence of zVAD-fmk. In sum, our data suggest a model in which TNFR2 sensitizes macrophages for endogenous TNF-induced TNFR1-mediated necroptosis by the known ability of TNFR2 to interfere with the survival activity of TRAF2-cIAP1/2 complexes.},
  language  = {en}
}
@article{KreckelAnanySiegmundetal.2019,
  author    = {Kreckel, Jennifer and Anany, Mohammed A. and Siegmund, Daniela and Wajant, Harald},
  title     = {TRAF2 controls death receptor-induced caspase-8 processing and facilitates proinflammatory signaling},
  series = {Frontiers in Immunology},
  volume    = {10},
  journal   = {Frontiers in Immunology},
  number    = {2024},
  doi       = {10.3389/fimmu.2019.02024},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201822},
  year      = {2019},
  abstract  = {Tumor necrosis factor (TNF) receptor associated factor-2 (TRAF2) knockout (KO) cells were generated to investigate the role of TRAF2 in signaling by TNFR1 and the CD95-type death receptors (DRs) TRAILR1/2 and CD95. To prevent negative selection effects arising from the increased cell death sensitivity of TRAF2-deficient cells, cell lines were used for the generation of the TRAF2 KO variants that were protected from DR-induced apoptosis downstream of caspase-8 activation. As already described in the literature, TRAF2 KO cells displayed enhanced constitutive alternative NFκB signaling and reduced TNFR1-induced activation of the classical NFκB pathway. There was furthermore a significant but only partial reduction in CD95-type DR-induced upregulation of the proinflammatory NFκB-regulated cytokine interleukin-8 (IL8), which could be reversed by reexpression of TRAF2. In contrast, expression of the TRAF2-related TRAF1 protein failed to functionally restore TRAF2 deficiency. TRAF2 deficiency resulted furthermore in enhanced procaspase-8 processing by DRs, but this surprisingly came along with a reduction in net caspase-8 activity. In sum, our data argue for (i) a non-obligate promoting function of TRAF2 in proinflammatory DR signaling and (ii) a yet unrecognized stabilizing effect of TRAF2 on caspase-8 activity.},
  language  = {en}
}
@article{KuckaLangZhangetal.2021,
  author    = {Kucka, Kirstin and Lang, Isabell and Zhang, Tengyu and Siegmund, Daniela and Medler, Juliane and Wajant, Harald},
  title     = {Membrane lymphotoxin-α\(_2\)β is a novel tumor necrosis factor (TNF) receptor 2 (TNFR2) agonist},
  series = {Cell Death \& Disease},
  volume    = {12},
  journal   = {Cell Death \& Disease},
  number    = {4},
  doi       = {10.1038/s41419-021-03633-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260077},
  pages     = {360},
  year      = {2021},
  abstract  = {In the early 1990s, it has been described that LTα and LTβ form LTα\(_2\)β and LTαβ\(_2\) heterotrimers, which bind to TNFR1 and LTβR, respectively. Afterwards, the LTαβ\(_2\)-LTβR system has been intensively studied while the LTα\(_2\)β-TNFR1 interaction has been ignored to date, presumably due to the fact that at the time of identification of the LTα\(_2\)β-TNFR1 interaction one knew already two ligands for TNFR1, namely TNF and LTα. Here, we show that LTα\(_2\)β interacts not only with TNFR1 but also with TNFR2. We furthermore demonstrate that membrane-bound LTα\(_2\)β (memLTα\(_2\)β), despite its asymmetric structure, stimulates TNFR1 and TNFR2 signaling. Not surprising in view of its ability to interact with TNFR2, LTα\(_2\)β is inhibited by Etanercept, which is approved for the treatment of rheumatoid arthritis and also inhibits TNF and LTα.},
  language  = {en}
}
@article{WajantSiegmund2019,
  author    = {Wajant, Harald and Siegmund, Daniela},
  title     = {TNFR1 and TNFR2 in the control of the life and death balance of macrophages},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {7},
  journal   = {Frontiers in Cell and Developmental Biology},
  number    = {91},
  doi       = {10.3389/fcell.2019.00091},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201551},
  year      = {2019},
  abstract  = {Macrophages stand in the first line of defense against a variety of pathogens but are also involved in the maintenance of tissue homeostasis. To fulfill their functions macrophages sense a broad range of pathogen- and damage-associated molecular patterns (PAMPs/DAMPs) by plasma membrane and intracellular pattern recognition receptors (PRRs). Intriguingly, the overwhelming majority of PPRs trigger the production of the pleiotropic cytokine tumor necrosis factor-alpha (TNF). TNF affects almost any type of cell including macrophages themselves. TNF promotes the inflammatory activity of macrophages but also controls macrophage survival and death. TNF exerts its activities by stimulation of two different types of receptors, TNF receptor-1 (TNFR1) and TNFR2, which are both expressed by macrophages. The two TNF receptor types trigger distinct and common signaling pathways that can work in an interconnected manner. Based on a brief general description of major TNF receptor-associated signaling pathways, we focus in this review on research of recent years that revealed insights into the molecular mechanisms how the TNFR1-TNFR2 signaling network controls the life and death balance of macrophages. In particular, we discuss how the TNFR1-TNFR2 signaling network is integrated into PRR signaling.},
  language  = {en}
}