@phdthesis{Mahmood2015,
  author    = {Mahmood, Zafar},
  title     = {Effect of cytokine inhibition on peripheral memory B cells in patients with Rheumatoid arthtritis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117334},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Objective: Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory autoimmune disease. Enhanced B cell activity has been proposed in the pathogenesis of RA along with different pro-inflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α), critically involved in chronic inflammation. Biological agents targeting these cytokines IL-6 and TNF-α have considerably advanced treatment of autoimmunity. Enhanced B cell activity, particularly memory B cells gained particularly interest in evaluating response during therapies from biologics. Human peripheral memory B cells can be distinguished by the phenotypic expression of CD27 and IgD defining three major B cell subpopulations: CD27+IgD+ pre-switch, CD27+IgD- post-switch and CD27-IgD- double negative (DN) memory B cells. Therefore, we analyzed different memory populations during cytokine inhibition by using tocilizumab (anti-IL-6R, TCZ) and adalimumab (anti-TNF-α, ADA), with focus on DN B cells Suspended. DN B cells lacking the conventional memory marker CD27, but due to their mutational Ig repertoire (IgR) considered in the memory compartment. However, only scare data are available for this DN subpopulation in RA. Methods: Phenotype analysis of activation markers (CD95 and ki-67) of B cell and their subsets were compared in RA patients (median age ~56 years) and in HD. DN memory B cells were phenotypically analyzed from RA patients during IL-6R or TNF-α inhibition at baseline week 12, week 24 and 1 year. Single B cell PCR approach was used to study Ig- receptors VH genes and isotype specific genes. Nonparametric Wilcoxon matched pair test and Mann-Whitney U test was used for statistical analysis by using GraphPadPrism 5. Univariate logistic regression was used to calculate odd ratios and correlation using Pearson r using SPSS statistics 22. Results: Surface and intracellular staining of B cells showed a significantly higher percentage of CD95 and ki-67 expressions in RA, which was highest in post-switch memory B cells followed by pre-switch and DN memory B cells. During cytokines (IL-6R \& TNF-α) inhibition, both CD95 and ki-67 expression were significantly reduced at week 12 and 24 along with reduction in their clinical parameters like DAS28, CRP, ESR. Furthermore, the phenotypic analysis in 107 RA patients and 49 healthy donors (HD) showed a significantly expanded population of DN B cells in RA which contain a heterogeneous mixture of IgA, IgG and IgM expressing cells with a clear dominance of IgG+ cells. Pre-therapy analysis of rearranged IgR sequences from patients (n=9) revealed that DN B cells carry rearranged heavy chain gene sequences with a diversified mutational pattern consistent with memory B cells. In contrast to tumor necrosis factor alpha (TNF-alpha) inhibition, a significant reduction in mutational frequency of BCR gene rearrangements at week 12, 24 and 1 year (p < 0.0001) was observed by in vivo IL-6R inhibition. These changes were observed for all BCR isotypes IgG, IgA and IgM at week 12, 24 and 1 year (p < 0.0001). IgA-RF, IgA serum level and IgA+ DN B cells decreased significantly (p < 0.05) at week 12 and week 24 during TCZ. Patients with a good European league against rheumatism (EULAR) response to TCZ had less DN B cells at baseline as compared to moderate responders (p = 0.006). Univariate logistic regression analysis revealed that the frequency of DN B cells at baseline is inversely correlated to a subsequent good EULAR response (p = 0.024) with an odds ratio of 1.48 (95\% confidence interval as 1.05-2.06). Conclusion: Both anti-TNF-α and anti-IL-6R could reduce higher B cell activity and improve disease activity tremendously in RA patients. The heterogeneous DN B cell compartment is expanded in RA and dominated by IgG isotype. TCZ can modulate the mutational status of DN Ig isotype receptors over 1 year. Interestingly, the frequency of DN B cells in RA may serve as a baseline predictor of subsequent EULAR response to TCZ.},
  subject      = {Arthrosis deformans},
  language  = {en}
}
@phdthesis{Zoelch2019,
  author    = {Z{\"o}lch, Michael Ludwig},
  title     = {Effekt der Interleukin-1 Rezeptor-assoziierten Kinase 2 (IRAK2)-Mutation N333D auf den Signalweg von TLR4},
  doi       = {10.25972/OPUS-18067},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180678},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {IRAK2 besitzt eine Schl{\"u}sselrolle im Signalweg des TLR4. Fehlregulationen dieses Signalwegs f{\"u}hren zu fehlgeleiteten Immunreaktionen, die auch die Entstehung und Progression von Krebserkrankungen f{\"o}rdern. Bevor IRAK2 als therapeutisches Ziel in Frage kommen kann, muss erst noch weitere Klarheit {\"u}ber die grunds{\"a}tzliche Funktionsweise dieses Proteins bestehen. So ist f{\"u}r IRAK2 aufgrund der Substitution einer Aminos{\"a}ure in der Kinase-Dom{\"a}ne im Vergleich zu IRAK1 noch nicht abschließend gekl{\"a}rt, ob es sich um eine aktive Kinase oder eine Pseudokinase handelt und ob diese Ver{\"a}nderung eine Erh{\"o}hung oder eine Erniedrigung der Funktion im TLR4-Signalweg nach sich zieht. Um diese Fragen anzugehen, wurde in dieser Arbeit Asparagin im vermeintlich aktiven Zentrum (Aminos{\"a}ure 333) wieder zur Asparagins{\"a}ure [N333D] revertiert und damit versucht die Phosphorylierungsaktivit{\"a}t zu steigern bzw. vergleichbar zu IRAK1 wiederherzustellen. Das Einbringen der Mutation in IRAK2 erfolgte mittels ortsspezifischer Mutagenese. Mit dieser und anderen Mutanten und mit wildtypischem IRAK2 wurden durch die CRISPR/Cas9-Methode generierte IRAK2-defiziente 264.7 Makrophagen rekonstituiert und damit ein System etabliert, mit dem der Einfluss der Mutation auf den Signalweg des TLR4 nach Stimulation mit LPS quantitativ analysiert werden konnte. Sowohl die indirekte NF-κB-Messung {\"u}ber CD40-Expression als auch die direkte NF-κB-Messung {\"u}ber die NF-κB-getriebene Expression eines Reportergens (cyan fluorescent protein) ergab, dass IRAK2[N333D] die LPS-abh{\"a}ngige NF-κB-Aktivierung {\"u}ber den TLR4 Signalweg schlechter erm{\"o}glicht als IRAK2. Insgesamt deuten die Ergebnisse darauf hin, dass die in der Entwicklungsgeschichte aufgetretene Ver{\"a}nderung des aktiven Zentrums von IRAK2 im Vergleich zu IRAK1 zu einer besseren Aktivierung der MyD88-abh{\"a}ngigen NF-κB-Aktivit{\"a}t f{\"u}hrte und somit eine erh{\"o}hte und l{\"a}nger anhaltende Signalleitung erm{\"o}glichte. Diese Erkenntnis kann als weiterer Schritt hin zu einem besseren Verst{\"a}ndnis der Funktion des IRAK2-Proteins und zu einer m{\"o}glichen zuk{\"u}nftigen Verwendung von IRAK2 als Ziel therapeutischer Behandlungen gesehen werden.},
  subject      = {Toll-like-Rezeptoren},
  language  = {de}
}
@phdthesis{Klingler2023,
  author    = {Klingler, Philipp},
  title     = {Exploration of proteasome interactions with human platelet function},
  doi       = {10.25972/OPUS-32108},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-321089},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Platelets are anucleated cell fragments derived from megakaryocytes. They play a fundamental role in hemostasis, but there is rising evidence that they are also involved in immunological processes. Despite absence of a nucleus, human platelets are capable of de novo protein synthesis and contain a fully functional proteasome system, which is, in nucleated cells, involved in processes like cell cycle progression or apoptosis by its ability of protein degradation. The physiological significance of the proteasome system in human platelets is not yet fully understood and subject of ongoing research. Therefore, this study was conducted with the intention to outline the role of the proteasome system for functional characteristics of human platelets. For experimentation, citrated whole blood from healthy donors was obtained and preincubated with proteasome inhibitors. In addition to the commonly used bortezomib, the potent and selective proteasome inhibitor carfilzomib was selected as a second inhibitor to rule out agent-specific effects and to confirm that observed changes are related to proteasome inhibition. Irreversibly induced platelet activation and aggregation were not affected by proteasome blockade with bortezomib up to 24 hours. Conversely, proteasome inhibition led to enhanced threshold aggregation and agglutination up to 25 \%, accompanied by partial alleviation of induced VASP phosphorylation of approximately 10-15 \%. Expression of different receptors were almost unaffected. Instead, a significant increase of PP2A activity was observable in platelets after proteasome blockade, accompanied by facilitated platelet adhesion to coated surfaces in static experiments or flow chamber experiments. Carfilzomib, used for the first time in functional experimentation with human platelets in vitro, led to a dose-dependent decrease of proteasome activity with accumulation of poly ubiquitylated proteins. Like bortezomib, carfilzomib treatment resulted in enhanced threshold aggregation with attenuated VASP phosphorylation. As the main conclusion of this thesis, proteasome inhibition enhances the responsiveness of human platelets, provided by an alleviation of platelet inhibitory pathways and by an additional increase of PP2A activity, resulting in facilitated platelet adhesion under static and flow conditions. The proteasome system appears to be involved in the promotion of inhibitory counterregulation in platelets. The potential of proteasome inhibitors for triggering thromboembolic adverse events in patients must be clarified in further studies, in addition to their possible use for targeting platelet function to improve the hemostatic reactivity of platelets.},
  subject      = {Thrombozyt},
  language  = {en}
}
@phdthesis{Joshi2021,
  author    = {Joshi, Hemant Kumar},
  title     = {Function of IRAK2 in macrophages and HECTD1 in B cells},
  doi       = {10.25972/OPUS-15084},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150846},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {The Immune system exerts its response against invading pathogens via a cumulative, sequential cooperation of immune cells coordinated by their secreted products. Immune cells, such as macrophages and dendritic cells (DCs), express toll-like receptors (TLRs) to sense the presence of pathogens through pathogen-associated molecular patterns (PAMPs). The interaction of PAMPs with TLRs elicits a cytosolic signaling cascade that enhances the expression of genes to stimulate inflammation. Interleukin 1 receptor-associated kinase 2 (IRAK2) is a component of the TLR signaling pathway. IRAK2 transduces the TLR signal via a direct interaction with TNF receptor-associated factor 6 (TRAF6) and subsequent enhancement of its ubiquitination. During my PhD thesis, I determined that a 55-amino acid long stretch at the C-terminal end of IRAK2 is important for TLR signaling. Overexpression of C-terminal truncated IRAK2 (IRAK2Δ55) in the murine macrophage cell line RAW 264.7 led to impaired CD40 expression after TLR4 stimulation by Lipopolysaccharide (LPS). I observed attenuated competency of IRAK2Δ55 in restoring a full TLR signaling response i.e. IL-6 secretion, NO production and CD40 expression in IRAK2-deficient RAW cells generated via CRISPR-Cas9 approach. Additionally, diminished TLR4 induced activation of nuclear factor κB (NF-κB) and extracellular signal related kinase (ERK) was observed with IRAK2Δ55 reconstituted RAW cells as compared to cell reconstituted with wildtype IRAK2. IRAK2Δ55 reconstituted RAW cells also exhibited reduced TLR4-induced cell death and phosphorylation of receptor interacting protein kinase 3 (RIP3). Co-immunoprecipitation experiments in HEK 293T cells showed that IRAK2Δ55 was still able to bind to TRAF6 alike IRAK2 but failed to induce ubiquitination of TRAF6. In conclusion, the results suggest that the IRAK2 TRAF6 interaction is not sufficient to sustain full TLR signaling. An C-terminus-dependent unknown molecular mechanism is also involved. Through my PhD work, I also analyzed a B cell lineage-specific HECTD1 knock-out mice. HECTD1 is an E3 ubiquitin ligase for various substrate proteins, such as heat shock protein 90 (HSP90), adenomatous polyposis coli and phosphatidylinositol phosphate kinase type 1 γ. Hsp90 regulates a variety of signaling molecules in NF-κB activation pathways which are essential for an optimal B cell response. HECTD1-deficient pro-B cells developed normally into mature B cells. However, TLR4 stimulated HECTD1-deficient B cells displayed reduced immunoglobulin (Ig) production in in vitro cultures. In addition, mice with HECTD1-deficient B cells showed a diminished Ig response after nitrophenylacetyl-keyhole limpet hemocyanin immunization. Thus, HECTD1 is necessary for efficient Ig secretion.},
  subject      = {Toll-like-Rezeptoren},
  language  = {en}
}
@phdthesis{Weirather2014,
  author    = {Weirather, Johannes},
  title     = {Role of CD4+ T lymphocytes in cardiac wound healing and remodeling after experimental myocardial infarction in mice},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-107225},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2014},
  abstract  = {Cardiac healing after myocardial infarction (MI) represents the cardinal prerequisite for proper replacement of the irreversibly injured myocardium. In contrast to innate immunity, the functional role of adaptive immunity in postinfarction healing has not been systematically addressed. The present study focused on the influence of CD4+ T lymphocytes on wound healing and cardiac remodeling after experimental myocardial infarction in mice. Both conventional and Foxp3+ regulatory CD4+ T cells (Treg cells) became activated in heart draining lymph nodes after MI and accumulated in the infarcted myocardium. T cell activation was strictly antigen-dependant as T cell receptor-transgenic OT-II mice in which CD4+ T cells exhibit a highly limited T cell receptor repertoire did not expand in heart-draining lymph nodes post-MI. Both OT-II and major histocompatibility complex class II-deficient mice lacking a CD4+ T cell compartment showed a fatal clinical postinfarction outcome characterized by disturbed scar tissue construction that resulted in impaired survival due to a prevalence of left-ventricular ruptures. To assess the contribution of anti-inflammatory Treg cells on wound healing after MI, the Treg cell compartment was depleted using DEREG mice that specifically express the human diphtheria toxin receptor in Foxp3-positive cells, resulting in Treg cell ablation after diphtheria toxin administration. In a parallel line of experiments, a second model of anti-CD25 antibody-mediated Treg cell immuno-depletion was used. Treg cell ablation prior to MI resulted in adverse postinfarction left-ventricular dilatation associated with cardiac deterioration. Mechanistically, Treg cell depletion resulted in an increased recruitment of pro-inflammatory neutrophils and Ly-6Chigh monocytes into the healing myocardium. Furthermore, Treg cell-ablated mice exhibited an adverse activation of conventional non-regulatory CD4+ and CD8+ T cells that showed a reinforced infiltration into the infarct zone. Increased synthesis of TNFα and IFNγ by conventional CD4+ and CD8+ T cells in hearts of Treg cell-depleted mice provoked an M1-like macrophage polarization characterized by heightened expression of healing-compromising induced NO synthase, in line with a reduced synthesis of healing-promoting transglutaminase factor XIII (FXIII), osteopontin (OPN) and transforming growth factor beta 1 (TGFβ1). Therapeutic Treg cell activation by a superagonistic anti-CD28 monoclonal antibody stimulated Treg cell accumulation in the infarct zone and led to an increased expression of mediators inducing an M2-like macrophage polarization state, i.e. interleukin-10, interleukin-13 and TGFβ1. M2-like macrophage differentiation in the healing infarct was associated with heightened expression of scar-forming procollagens as well as scar-stabilizing FXIII and OPN, resulting in improved survival due to a reduced incidence of left-ventricular ruptures. Therapeutic Treg cell activation and the induction of a beneficial M2-like macrophage polarization was further achieved by employing a treatment modality of high clinical potential, i.e. by therapeutic administration of IL-2/ anti-IL-2 monoclonal antibody complexes. The findings of the present study suggest that therapeutic Treg cell activation and the resulting improvement of healing may represent a suitable strategy to attenuate adverse infarct expansion, left-ventricular remodeling, or infarct ruptures in patients with MI.},
  subject      = {Antigen CD4},
  language  = {en}
}