Laboratory of Molecular Gastroenterology

Kiel, Germany

Laboratory of Molecular Gastroenterology

Kiel, Germany
SEARCH FILTERS
Time filter
Source Type

Gianelli U.,Hematopathology Service | Celesti G.,Laboratory of Molecular Gastroenterology | Anselmo A.,Laboratory of Molecular Gastroenterology | Laghi L.,Laboratory of Molecular Gastroenterology | And 6 more authors.
Stem Cells | Year: 2016

Abstract: Extracellular matrix (ECM) components initiate crucial biochemical and biomechanical cues that are required for bone marrow homeostasis. In our research, we prove that a peri-cellular matrix composed primarily of type III and type IV collagens, and fibronectin surrounds human megakaryocytes in the bone marrow. The data we collected support the hypothesis that bone marrow megakaryocytes possess a complete mechanism to synthesize the ECM components, and that thrombopoietin is a pivotal regulator of this new function inducing transforming growth factor-β1 (TGF-β1) release and consequent activation of the downstream pathways, both in vitro and in vivo. This activation results in a dose dependent increase of ECM component synthesis by megakaryocytes, which is reverted upon incubation with JAK and TGF-β1 receptor specific inhibitors. These data are pivotal for understanding the central role of megakaryocytes in creating their own regulatory niche within the bone marrow environment. © 2016 AlphaMed Press.


Arfmann-Knubel S.,Laboratory of Molecular Gastroenterology | Struck B.,Laboratory of Molecular Gastroenterology | Genrich G.,Institute of Experimental Medicine | Helm O.,Institute of Experimental Medicine | And 3 more authors.
PLoS ONE | Year: 2015

Nrf2 and TGF-β1 both affect tumorigenesis in a dual fashion, either by preventing carcinogen induced carcinogenesis and suppressing tumor growth, respectively, or by conferring cytoprotection and invasiveness to tumor cells during malignant transformation. Given the involvement of Nrf2 and TGF-β1 in the adaptation of epithelial cells to persistent inflammatory stress, e. g. of the pancreatic duct epithelium during chronic pancreatitis, a crosstalk between Nrf2 and TGF-β1 can be envisaged. By using premalignant human pancreatic duct cells (HPDE) and the pancreatic ductal adenocarcinoma cell line Colo357, we could show that Nrf2 and TGF-β1 independently but additively conferred an invasive phenotype to HPDE cells, whereas acting synergistically in Colo357 cells. This was accompanied by differential regulation of EMT markers like vimentin, Slug, L1CAM and E-cadherin. Nrf2 activation suppressed E-cadherin expression through an as yet unidentified ARE related site in the E-cadherin promoter, attenuated TGF-β1 induced Smad2/3-Activity and enhanced JNK-signaling. In Colo357 cells, TGF-β1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-β1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ. In Colo357, but not in HPDE cells, the effects of TGF-β1 on invasion were sensitive to Nrf2 knock-down. In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2. Thus, the increased invasion of both cell lines relates to the Nrf2-dependent downregulation of E-cadherin expression. In line, immunohistochemistry analysis of human pancreatic intraepithelial neoplasias in pancreatic tissues from chronic pancreatitis patients revealed strong Nrf2 activity already in premalignant epithelial duct cells, accompanied by partial loss of E-cadherin expression. Our findings indicate that Nrf2 and TGF-β1 both contribute to malignant transformation through distinct EMT related mechanisms accounting for an invasive phenotype. Provided a crosstalk between both pathways, Nrf2 and TGF-β1 mutually promote their tumorigenic potential, a condition manifesting already at an early stage during inflammation induced carcinogenesis of the pancreas. Copyright: © 2015 Arfmann-Knubel et al.


PubMed | Institute of Experimental Medicine, University of Tübingen and Laboratory of Molecular Gastroenterology
Type: Journal Article | Journal: PloS one | Year: 2015

Nrf2 and TGF-1 both affect tumorigenesis in a dual fashion, either by preventing carcinogen induced carcinogenesis and suppressing tumor growth, respectively, or by conferring cytoprotection and invasiveness to tumor cells during malignant transformation. Given the involvement of Nrf2 and TGF-1 in the adaptation of epithelial cells to persistent inflammatory stress, e.g. of the pancreatic duct epithelium during chronic pancreatitis, a crosstalk between Nrf2 and TGF-1 can be envisaged. By using premalignant human pancreatic duct cells (HPDE) and the pancreatic ductal adenocarcinoma cell line Colo357, we could show that Nrf2 and TGF-1 independently but additively conferred an invasive phenotype to HPDE cells, whereas acting synergistically in Colo357 cells. This was accompanied by differential regulation of EMT markers like vimentin, Slug, L1CAM and E-cadherin. Nrf2 activation suppressed E-cadherin expression through an as yet unidentified ARE related site in the E-cadherin promoter, attenuated TGF-1 induced Smad2/3-activity and enhanced JNK-signaling. In Colo357 cells, TGF-1 itself was capable of inducing Nrf2 whereas in HPDE cells TGF-1 per-se did not affect Nrf2 activity, but enhanced Nrf2 induction by tBHQ. In Colo357, but not in HPDE cells, the effects of TGF-1 on invasion were sensitive to Nrf2 knock-down. In both cell lines, E-cadherin re-expression inhibited the proinvasive effect of Nrf2. Thus, the increased invasion of both cell lines relates to the Nrf2-dependent downregulation of E-cadherin expression. In line, immunohistochemistry analysis of human pancreatic intraepithelial neoplasias in pancreatic tissues from chronic pancreatitis patients revealed strong Nrf2 activity already in premalignant epithelial duct cells, accompanied by partial loss of E-cadherin expression. Our findings indicate that Nrf2 and TGF-1 both contribute to malignant transformation through distinct EMT related mechanisms accounting for an invasive phenotype. Provided a crosstalk between both pathways, Nrf2 and TGF-1 mutually promote their tumorigenic potential, a condition manifesting already at an early stage during inflammation induced carcinogenesis of the pancreas.


Kruse M.-L.,Laboratory of Molecular Gastroenterology | Friedrich M.,Laboratory of Molecular Gastroenterology | Arlt A.,Laboratory of Molecular Gastroenterology | Rocken C.,University of Kiel | And 4 more authors.
Inflammatory Bowel Diseases | Year: 2016

Background: The antioxidant transcription factor Nrf2 confers broad cytoprotection and has a dual role in tumorigenesis. Enhancing proteasome activity is one mechanism by which Nrf2 can promote cancer development, e.g., colorectal cancer. This study investigated whether this potential oncogenic effect of Nrf2 emerges already from the epithelial adaptation to persistent oxidative stress during inflammatory bowel disease (IBD). Methods: Reactive oxygen species (ROS)-producing inflammatory myeloid cells (IMCs) from colon tissue of patients with IBD were cocultured with human NCM460 colonocytes. ARE-luciferase-, c-H 2 DCF-DA-assays, Western blotting, and quantitative polymerase chain reaction were performed for assessing Nrf2-activity, intracellular ROS-level, and Nrf2-target gene expression. Proteasome activity was quantified by Suc-LLVY-amido-4-methylcumarin-assay, and apoptosis by caspase-3/-7 assay and PARP1-Western blots. Nrf2, proteasome proteins, and IMCs were analyzed in IBD-tissues by immunohistochemistry. Results: IMC-coculture caused a temporary increase of ROS in NCM460, followed by Nrf2 activation and elevated expression of ROS-protecting enzymes (NQO1, GCLC). This was accompanied by Nrf2-dependent expression of proteasome proteins (PSMD4, PSMA5) and an enhanced proteasome activity in IMC-cocultured NCM460. Nrf2-siRNA or the ROS-scavenger Tiron blocked these alterations. Depending on Nrf2-induced proteasome activity, IMC-cocultured NCM460 or Colo320 cancer cells were less sensitive to apoptosis (TRAIL-/etoposide induced). Immunostaining of IBD-tissues confirmed Nrf2 activation in the colonic epithelium within inflamed areas, along with greater proteasome protein expression. Conclusions: IMC/NCM460-coculture experiments and immunohistochemistry of colonic tissues from patients with IBD reveal a Nrf2-dependent adaptation of colon epithelial cells to oxidative stress caused by inflammatory cells. This involves increased proteasome activity and apoptosis resistance that protect from tissue damage due to colitis on one hand, but on the other hand, may favor carcinogenesis. Copyright © 2016 Crohn's & Colitis Foundation of America, Inc.

Loading Laboratory of Molecular Gastroenterology collaborators
Loading Laboratory of Molecular Gastroenterology collaborators