Project description:The liver exhibits a unique capacity for regeneration in response to injury. Lymphotoxin β Receptor (LTβR), a core member of the Tumor Necrosis Factor (TNF)/TNF Receptor (TNFR) superfamily is known to play an important role in this process. However, LTβR functions in the pathophysiological alterations and molecular mechanisms of liver regeneration are so far ill-characterized. Interestingly, LTβR / mice suffered from increased and prolonged liver tissue damage after 70 % hepatectomy (PHx), a finding accompanied by elevated alkaline phosphatase levels and deregulated bile acid (BA) homeostasis. Pronounced differences in the expression patterns of genes relevant for BA synthesis and recirculation were observed. Transcriptome analysis revealed a marked disparity in gene expression programs in LTβR / vs. WT liver tissue, where gene ontology (GO) terms related to transcription, gene expression and metabolic pathways were over-represented in the latter. In addition, murinoglobulin 2 (Mug2), a gene product to date not implicated in liver regeneration, was identified as one of the most differentially regulated genes after PHx in WT compared to LTβR / and TNFRp55-/- livers. LTβR and TNFRp55 share downstream signaling elements. TNFRp55 is known to also play an important role in liver regeneration after PHx. Therefore, LTβR / mice were treated with Etanercept to create mice functionally deficient in both signaling pathways. Strikingly, the combined blockade of TNFR and LTβR signaling leads to complete failure of liver regeneration resulting in death within 24 to 48 hours after PHx. LTβR is essential for efficient liver regeneration and cooperates with TNFRp55 in this process. Differences in survival kinetics strongly suggest distinct functions for these two cytokine receptors in liver regeneration. Failure of TNFR and LTβR signaling renders liver regeneration impossible.
Project description:The liver exhibits a unique capacity for regeneration in response to injury. Lymphotoxin β Receptor (LTβR), a core member of the Tumor Necrosis Factor (TNF)/TNF Receptor (TNFR) superfamily is known to play an important role in this process. However, LTβR functions in the pathophysiological alterations and molecular mechanisms of liver regeneration are so far ill-characterized. Interestingly, LTβR / mice suffered from increased and prolonged liver tissue damage after 70 % hepatectomy (PHx), a finding accompanied by elevated alkaline phosphatase levels and deregulated bile acid (BA) homeostasis. Pronounced differences in the expression patterns of genes relevant for BA synthesis and recirculation were observed. Transcriptome analysis revealed a marked disparity in gene expression programs in LTβR / vs. WT liver tissue, where gene ontology (GO) terms related to transcription, gene expression and metabolic pathways were over-represented in the latter. In addition, murinoglobulin 2 (Mug2), a gene product to date not implicated in liver regeneration, was identified as one of the most differentially regulated genes after PHx in WT compared to LTβR / and TNFRp55-/- livers. LTβR and TNFRp55 share downstream signaling elements. TNFRp55 is known to also play an important role in liver regeneration after PHx. Therefore, LTβR / mice were treated with Etanercept to create mice functionally deficient in both signaling pathways. Strikingly, the combined blockade of TNFR and LTβR signaling leads to complete failure of liver regeneration resulting in death within 24 to 48 hours after PHx. LTβR is essential for efficient liver regeneration and cooperates with TNFRp55 in this process. Differences in survival kinetics strongly suggest distinct functions for these two cytokine receptors in liver regeneration. Failure of TNFR and LTβR signaling renders liver regeneration impossible.
Project description:In human chronic lymphocytic leukemia (CLL) pathogenesis B cell antigen receptor signaling seems important for leukemia B cell ontogeny, whereas the microenvironment influences B cell activation, tumor cell lodging and provision of antigenic stimuli. Using the murine Eμ-Tcl1 CLL model, we demonstrate that CXCR5-controlled access to follicular dendritic cells (FDCs) confers proliferative stimuli to leukemia B cells. Intravital imaging revealed a marginal zone B cell-like leukemia cell trafficking route. Murine and human CLL cells reciprocally stimulated resident mesenchymal stromal cells through lymphotoxin-β-receptor activation, resulting in CXCL13 secretion and stromal compartment remodeling. Inhibition of lymphotoxin/lymphotoxin-β-receptor signaling or of CXCR5 signaling retards leukemia progression. Thus, CXCR5 activity links tumor cell homing, shaping a survival niche, and access to localized proliferation stimuli.
Project description:Purpose: We aim to identify changes in the miRNA-ome upon lymphotoxin beta receptor activation Methods: miRNAs were analyzed by sequencing after 2 and 4 days of treatment Results: We could identify different clusters with distinct time-dependent expression after treatment Conclusion: The miRNA-ome is responding on lymphotoxin beta receptor activation
Project description:The liver has a remarkable ability to regenerate, with the best experimental model for regeneration being partial hepatectomy (PHx), in which up to two-thirds of the liver may be removed, and the residual lobes enlarge to make up for the missing mass in a few days’ time. Liver regeneration has been extensively studied, mainly in rodent models, and characterized in terms of transcriptional regulation of gene expression. However, little is known regarding regulation of gene expression in a human model of regeneration following PHx. We used microarrays to follow gene expression changes shortly following PHx. Experiment Overall Design: Liver tissues were collected from patients undergoing a PHx surgery (1.5, 42 and 81 years) under an IRB approval, at the onset (T0) and shortly after PHx (0.5hr, 1hr and 1.5hrs) for RNA extraction and hybridization on Affymetrix microarrays.