Biotechnology Institute Thurgau

Abstract Adverse environmental conditions in water bodies, such as currents and waves, can be very stressful for net cage structures of fish farms. This work aims to develop a simulation model that can qualitatively estimate the mechanical loads in the wires of net cage segments of specific fish farms due to current influences. To set up the model, flow measurements were carried out in a wind tunnel on net cage surfaces with different wire diameters and mesh sizes. Different flow angles were tested. These measurements were validated by flow simulations in Ansys CFX. In order to minimize the simulation time, the net cage surfaces of the aquaculture systems were replaced by porous media. Functions for drag and lift coefficients as well as velocity reduction factors were derived from the flow simulations in dependence on porosity and angle of attack. A fluid-structure interaction was performed by transferring these functions to a beam-node model created with Ansys APDL representing the entire aquaculture facility. The simulation model makes it possible to qualitatively determine the mechanical stresses in the individual wires of the net cage surfaces. The findings on the most stressed areas can be used to optimize the design of the aquaculture systems in detail using the submodel technology.

Selective erythroid atypical chemokine receptor 1 deficiency exacerbated disease activity in experimental GN via changes of the myeloid lineage. Activated monocytes and profibrogenic phenotypes of macrophages underlaid the kidney phenotype observed in erythroid-silent individuals. Genetically modified mouse models showed pathomechanisms of kidney diseases in patients of West African ancestry with erythroid atypical chemokine receptor 1 deficiency. Single-nucleotide polymorphisms of the atypical chemokine receptor 1 ( ACKR1 ) gene encode human Duffy antigen blood groups. Most individuals of West African ancestry carry a single-nucleotide polymorphism in the promoter region of the ACKR1 gene that disrupts its transcription in erythroid cells but not in venular endothelial cells, leading to an erythroid-silent, FyBES Duffy phenotype. We used two mouse models of erythroid-selective ACKR1 deficiency to delineate the fundamental role of this receptor in the erythroid compartment in regulating the development of experimental immune-mediated kidney disease. Humanized transgenic Duffy erythroid-silent Duffy-negative transgene mice and chimeric wild-type mice transplanted with ACKR1-deficient bone marrow, both selectively lacking erythroid ACKR1, showed increased disease activity and fibrosis after induction of nephrotoxic serum nephritis, as compared with their respective controls. Mice lacking erythroid ACKR1 exhibited altered serum chemokine levels and bone marrow monocytes displaying activated and promigratory phenotypes. Moreover, they showed an increase in kidney-infiltrating macrophages that were characterized by a profibrotic transcriptome signature. No changes in ACKR1 expression in kidney vascular endothelial cells were seen in erythroid ACKR1-deficient mice with or without nephrotoxic serum nephritis. Our data demonstrates that erythroid-specific ACKR1 deficiency led to an increased infiltration of the kidney by macrophages with an altered profibrotic phenotype in nephrotoxic serum nephritis, resulting in aggravated kidney disease.

Autoimmune and inflammatory diseases are characterized by aberrant immune responses. The immunoproteasome was proposed as a target for such Th cell-mediated diseases due to its role in the activation, differentiation and function of T cells. Even though many studies demonstrated reductions in Th17 cells upon immunoproteasome inhibition, it is still unclear if the differentiation or survival of these cells is affected. Therefore, this study used DSS-induced colitis and house dust mite airway inflammation mouse models to investigate the effect of immunoproteasome inhibition on Th17 cells and Tregs at different time points. Th17 cells were almost abolished when immunoproteasome inhibition was applied continuously in DSS-induced colitis. In contrast, immunoproteasome inhibition did not decrease levels of already differentiated Th17 cells and did not enhance Treg induction. Dendritic cells were barely affected by immunoproteasome inhibition. Moreover, immunoproteasome inhibition reduced T cell activation in vitro and in vivo, suggesting impaired activation as the underlying mechanism for reduced Th17 differentiation. In conclusion, immunoproteasome inhibition reduces Th17 differentiation by impairing the activation of naïve T cells, but it does not affect the survival of already-differentiated Th17 cells and Tregs.

The ubiquitin-like modifier FAT10 is strongly expressed in dendritic cells (DCs) and upregulated during inflammation. Interleukin (IL)-12 plays a critical role in promoting CD4+ T cell differentiation into Th1 cells and in IFN-γ induction in T cells. Previously, it was shown that FAT10 is required for IFN-γ expression of activated T cells. In this study, we investigated whether FAT10 influences IL-12 expression or IL-12 induced signaling and thereby contributes to the reduced IFN-γ expression. Presence or absence of FAT10 did not alter IL-12 expression in DC2.4 cells and in bone marrow derived DCs. Furthermore, FAT10 had no influence on the differentiation of naïve T helper cells to Th1 cells under Th1 polarizing conditions. Additionally, FAT10 did not alter STAT4 phosphorylation in IL-12 receptor stimulated T cells. Taken together, FAT10 neither influences IL-12 expression in DCs nor affects IL-12 receptor signaling in T cells. Hence, the previously observed influence of FAT10 on IFN-γ secretion is not mediated by IL-12.

BackgroundHow to select muscle-invasive bladder cancer (MIBC) patients who are sensitive to immunotherapy is an unmet medical need. This study aimed to explore the role of immunoproteasome subunits as a novel signature for predicting efficacy of immunotherapy in MIBC.MethodsThe expression profile of immunoproteasome subunits of MIBC and normal tissues was evaluated from data of The Cancer Genome Atlas (TCGA) and of the Chongqing University Cancer Hospital (CQUCH) cohort. Survival analysis and response to immunotherapy was further explored and compared between immunoproteasome subunitshigh and immunoproteasome subunitslow MIBC patients in the TCGA, the CQUCH and the IMvigor210 cohort. The association of the expression of immunoproteasome subunits with immune checkpoint molecules and the tumor immune microenvironment was explored by immunohistochemistry staining and bioinformatic analysis in MIBC of these three cohorts.ResultsThe expression of the immunoproteasome subunits PSMB8, PSMB9 and PSMB10 was significantly upregulated in MIBC. MIBC patients with high expression of immunoproteasome subunits, especially high expression of PSMB9, showed a trend of prolonged overall and progression free survival, which was further significantly improved in response to immunotherapy. Bioinformatics and immunohistochemistry staining revealed a positive correlation of the expression of immunoproteasome subunits with the expression of immune checkpoint molecules, with T cell activation and with T cell-mediated cytotoxicity.ConclusionsImmunoproteasome subunits, in particular PSMB9, are immune microenvironment-related molecules of MIBC and are promising signatures for survival prediction in response to immunotherapy of MIBC.Graphical

BackgroundAtypical chemokine receptors (ACKRs) play an important role in regulating the availability of chemokines and are responsible for the formation of chemokine gradients required for the directed migration of immune cells in health and disease. ACKR4 shapes gradients of the chemokines CCL19 and CCL21, which are essential for guiding leukocyte homing to lymphoid organs where they initiate an adaptive immune response against invading pathogens. How ACKRs internalize and scavenge chemokines on the molecular level remains poorly understood. Current state-of the art methods to study βarrestin recruitment, signaling and trafficking of ACKRs - and G-protein-coupled receptors in general - rely heavily on C-terminally tagged receptors with unknown consequences for receptor functions.MethodsFluorescently labelled CCL19 was used to quantify chemokine internalization by native and tagged receptors as assessed by flow cytometry and live cell confocal microscopy. Steady-state interaction and chemokine-driven recruitment of βarrestins was determined by NanoBiT bystander assays. βarrestin-dependency for CCL19 internalization was determined in wild-type versus βarrestin1/2-double deficient cell lines. Statistical significance was determined by unpaired t-test or one-way ANOVA with Dunnett’s or Tukey’s multiple comparison tests.ResultsAddition of a C-terminal tag selectively affected the function of ACKR4, but not other ACKRs. Fusing a short peptide tag or a fluorescent protein to ACKR4 significantly augmented its ability to internalize its cognate ligand CCL19. In comparison to native ACKR4, its C-terminal tagging provoked an elevated pre-association of βarrestins with the plasma membrane, yet a reduction in chemokine-driven βarrestin recruitment. Furthermore, the addition of a C-terminal tag led to a shift from a βarrestin-dependent towards a βarrestin-independent endocytosis pathway. Similar results on chemokine uptake and on βarrestin-dependency were obtained with ACKR4 variants, in which a putative class II PDZ-binding domain located at the C-terminal tip of the receptor was mutated.ConclusionThis study identifies that the integrity of the C-terminus of ACKR4 is critical for receptor function. The addition of a C-terminal tag to ACKR4 enhances chemokine uptake and alters the involvement of βarrestins in receptor trafficking.

Abstract GPR182/ACKR5, the most recently deorphanized chemokine receptor, is mainly expressed on endothelial cells and was proposed to act as a scavenger regulating the availability of a large set of chemokines. In this study, we first established the exact profiles and ranking of the chemokines binding to the human and mouse GPR182. We confirmed the high promiscuity of GPR182 towards XC, CC and CXC chemokines and a clear difference in the chemokine repertoires of the human and mouse orthologues. We next demonstrated that, beyond classical chemokines, GPR182 exhibits potent binding to the chemoattractant protein GPR15L/C10orf99, the atypical chemokine CXCL17 and various endogenous peptides, mainly from the opioid, apelin, and PACAP families. We also showed that these newly identified ligands engage GPR182 through varied binding modes. While GPR15L, just like classical chemokines, predominantly engages GPR182 via its N terminus, conversely to the C terminus-dependent binding to its cognate receptor GPR15, CXCL17 exhibits a more complex interaction, relying on both the N and C terminus. The binding mode of the newly identified peptide ligands also differ from the interactions with their cognate receptors. Our findings establish the first scavenger receptor for CXCL17 and GPR15L and advance the understanding of GPR182 ligand interactions, suggesting a regulatory role beyond chemokines.

IFN-I secretion provides a rapid host defense against infection with RNA viruses. Within the host cell, viral RNA triggers the activation of the RIG-I signaling pathway, leading to the production of IFN-I. Because an exaggerated IFN-I response causes severe tissue damage, RIG-I signaling is tightly regulated. One of the factors that control the IFN-I response is the ubiquitin-like modifier FAT10, which is induced by TNF and IFNγ and targets covalently FAT10-linked proteins for proteasomal degradation. However, the mechanism of how FAT10 modulates IFN-I secretion remains to be fully elucidated. Here, we provide strong evidence that FAT10 is phosphorylated by IκB kinase β (IKKβ) upon TNF stimulation and during influenza A virus infection on several serine and threonine residues. FAT10 phosphorylation increases the binding of FAT10 to the TRAF3-deubiquitylase OTUB1 and its FAT10-mediated activation. Consequently, FAT10 phosphorylation results in a low ubiquitylation state of TRAF3, which is unable to maintain interferon regulatory factor 3 phosphorylation and downstream induction of IFN-I. Taken together, we reveal a mechanism of how phosphorylation of FAT10 limits the production of tissue-destructive IFN-I in inflammation.

T cell activation requires engagement of a cognate antigen by the T cell receptor (TCR) and the co-stimulatory signal of CD28. Both TCR and CD28 aggregate into clusters at the plasma membrane of activated T cells. While the role of TCR clustering in T cell activation has been extensively investigated, little is known about how CD28 clustering contributes to CD28 signalling. Here, we report that upon CD28 triggering, the BAR-domain protein sorting nexin 9 (SNX9) is recruited to CD28 clusters at the immunological synapse. Using three-dimensional correlative light and electron microscopy, we show that SNX9 generates membrane tubulation out of CD28 clusters. Our data further reveal that CD28 clusters are in fact dynamic structures and that SNX9 regulates their stability as well as CD28 phosphorylation and the resulting production of the cytokine IL-2. In summary, our work suggests a model in which SNX9-mediated tubulation generates a membrane environment that promotes CD28 triggering and downstream signalling events.

Abstract A novel implant system for bone elongation will be presented. With this technique, the body's own bone material, so-called callus, can be formed by gradual distraction of the tubular bones, thus achieving an extension of femur and tibia bones. The driving principle of this fully implantable bone lengthening system is based on a shape memory element. During the surgical treatment, the intramedullary nail serves to stabilize the severed bone and enables the formation of new, endogenous bone material to lengthen the limbs or to bridge bone defects. The intramedullary nail is implanted into the medullary cavity and fixed at both ends with locking bolts. A receiver coil implanted under the skin receives the necessary energy twice a day through high-frequency energy transport to activate the thermal phase transformation of the shape memory element. This gradually increases the bone gap by 0.5 mm each time and stimulates callus formation. Consequently, osteoblasts or osteocytes are formed in the area of the desired bone extension and load-bearing bone material is formed. Three nail prototypes have already been tested for their functionality in a cadaver study in a German clinic. Currently a redesign of this intelligent implant system is underway, focusing on a novel coil geometry, a monitoring sensor system and control technology and a novel connection technology for the drive components. With this intelligent implant system, it will be possible for the first time to lengthen the bones in a patient-friendly manner and to continuously monitor, document and evaluate the entire lengthening process.KeywordsBone elongationLimb lengtheningNiTiShape memoryJoining technologyMonitoring sensor system