Publications by authors named "Julia Strangmann"

6 Publications

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Anti-inflammatory chemoprevention attenuates the phenotype in a mouse model of esophageal adenocarcinoma.

Carcinogenesis 2021 Apr 20. Epub 2021 Apr 20.

Department of Medicine II, Klinikum rechts der Isar, Technical University Munich (TUM), Ismaninger Str, München, Germany.

Barrett´s Esophagus (BE) is the main known precursor condition of Esophageal Adenocarcinoma (EAC). BE is defined by the presence of metaplasia above the normal squamous columnar junction and has mainly been attributed to gastroesophageal reflux disease (GERD) and chronic reflux esophagitis. Thus, the rising incidence of EAC in the Western world is likely mediated by chronic esophageal inflammation, secondary to GERD in combination with environmental risk factors such as a Western diet and obesity. However, (at present) risk prediction tools and endoscopic surveillance have shown limited effectiveness. Chemoprevention as an adjunctive approach remains an attractive option to reduce the incidence of neoplastic disease. Here, we investigate the feasibility of chemopreventive approaches in BE and EAC via inhibition of inflammatory signaling in a transgenic mouse model of BE and EAC (L2-IL1B mice), with accelerated tumor formation on a high fat diet (HFD). L2-IL1B mice were treated with the IL-1 receptor antagonist Anakinra and the nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin or Sulindac. Interleukin-1b antagonism reduced tumor progression in L2-IL1B mice with or without a HFD, while both NSAIDs were effective chemoprevention agents in the accelerated HFD fed L2-IL1B mouse model. Sulindac treatment also resulted in a marked change in the immune profile of L2-IL-1B mice. In summary, anti-inflammatory treatment of HFD-treated L2-IL1B mice acted protectively on disease progression. These results from a mouse model of BE support results from clinical trials that suggest that anti-inflammatory medication may be effective in the chemoprevention of EAC.
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http://dx.doi.org/10.1093/carcin/bgab032DOI Listing
April 2021

Notch signaling drives development of Barrett's metaplasia from Dclk1-positive epithelial tuft cells in the murine gastric mucosa.

Sci Rep 2021 Feb 24;11(1):4509. Epub 2021 Feb 24.

Klinik und Poliklinik für Innere Medizin II, Technical University of Munich, Munich, Germany.

Barrett's esophagus (BE) is a precursor to esophageal adenocarcinoma (EAC), but its cellular origin and mechanism of neoplastic progression remain unresolved. Notch signaling, which plays a key role in regulating intestinal stem cell maintenance, has been implicated in a number of cancers. The kinase Dclk1 labels epithelial post-mitotic tuft cells at the squamo-columnar junction (SCJ), and has also been proposed to contribute to epithelial tumor growth. Here, we find that genetic activation of intracellular Notch signaling in epithelial Dclk1-positive tuft cells resulted in the accelerated development of metaplasia and dysplasia in a mouse model of BE (pL2.Dclk1.N2IC mice). In contrast, genetic ablation of Notch receptor 2 in Dclk1-positive cells delayed BE progression (pL2.Dclk1.N2fl mice), and led to increased secretory cell differentiation. The accelerated BE progression in pL2.Dclk1.N2IC mice correlated with changes to the transcriptomic landscape, most notably for the activation of oncogenic, proliferative pathways in BE tissues, in contrast to upregulated Wnt signalling in pL2.Dclk1.N2fl mice. Collectively, our data show that Notch activation in Dclk1-positive tuft cells in the gastric cardia can contribute to BE development.
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http://dx.doi.org/10.1038/s41598-021-84011-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904766PMC
February 2021

Elimination of NF-κB signaling in Vimentin+ stromal cells attenuates tumorigenesis in a mouse model of Barrett's Esophagus.

Carcinogenesis 2021 04;42(3):405-413

Department of Medicine II, Klinikum rechts der Isar, Technical University Munich (TUM), München, Germany.

Chronic inflammation induces Barrett's Esophagus (BE) which can advance to esophageal adenocarcinoma. Elevated levels of interleukin (IL)-1b, IL-6 and IL-8 together with activated nuclear factor-kappaB (NF-κB), have been identified as important mediators of tumorigenesis. The inflammatory milieu apart from cancer cells and infiltrating immune cells contains myofibroblasts (MFs) that express aSMA and Vimentin. As we observed that increased NF-κB activation and inflammation correlates with increased MF recruitment and an accelerated phenotype we here analyze the role of NF-κB in MF during esophageal carcinogenesis in our L2-IL-1B mouse model. To analyze the effect of NF-κB signaling in MFs, we crossed L2-IL-1B mice to tamoxifen inducible Vim-Cre (Vim-CreTm) mice and floxed RelA (p65fl/fl) mice to specifically eliminate NF-κB signaling in MF (IL-1b.Vim-CreTm.p65fl/fl). The interaction of epithelial cells and stromal cells was further analyzed in mouse BE organoids and patient-derived human organoids. Histological scoring of IL-1b.Vim-CreTm.p65fl/fl mice showed a significantly attenuated phenotype compared with L2-IL-1B mice, with mild inflammation, decreased metaplasia and no dysplasia. This correlated with decreased proliferation and increased differentiation in cardia tissue of IL-1b.Vim-CreTm.p65fl/fl compared with L2-IL-1B mice. Distinct changes of cytokines and chemokines within the local microenvironment in IL-1b.Vim-CreTm.p65fl/fl mice reflected the histopathological abrogated phenotype. Co-cultured NF-κB inhibitor treated MF with mouse BE organoids demonstrated NF-κB-dependent growth and migration. MFs are essential to form an inflammatory and procarcinogenic microenvironment and NF-κB signaling in stromal cells emerges as an important driver of esophageal carcinogenesis. Our data suggest anti-inflammatory approaches as preventive strategies during surveillance of BE patients.
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http://dx.doi.org/10.1093/carcin/bgaa109DOI Listing
April 2021

Characterizing caspase-1 involvement during esophageal disease progression.

Cancer Immunol Immunother 2020 Dec 1;69(12):2635-2649. Epub 2020 Jul 1.

School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.

Barrett's esophagus (BE) is an inflammatory condition and a neoplastic precursor to esophageal adenocarcinoma (EAC). Inflammasome signaling, which contributes to acute and chronic inflammation, results in caspase-1 activation leading to the secretion of IL-1β and IL-18, and inflammatory cell death (pyroptosis). This study aimed to characterize caspase-1 expression, and its functional importance, during disease progression to BE and EAC. Three models of disease progression (Normal-BE-EAC) were employed to profile caspase-1 expression: (1) a human esophageal cell line model; (2) a murine model of BE; and (3) resected tissue from BE-associated EAC patients. BE patient biopsies and murine BE organoids were cultured ex vivo in the presence of a caspase-1 inhibitor, to determine the importance of caspase-1 for inflammatory cytokine and chemokine secretion.Epithelial caspase-1 expression levels were significantly enhanced in BE (p < 0.01). In contrast, stromal caspase-1 levels correlated with histological inflammation scores during disease progression (p < 0.05). Elevated secretion of IL-1β from BE explanted tissue, compared to adjacent normal tissue (p < 0.01), confirmed enhanced activity of caspase-1 in BE tissue. Caspase-1 inhibition in LPS-stimulated murine BE organoids caused a significant reduction in IL-1β (p < 0.01) and CXCL1 (p < 0.05) secretion, confirming the importance of caspase-1 in the production of cytokines and chemokines associated with disease progression from BE to EAC. Targeting caspase-1 activity in BE patients should therefore be tested as a novel strategy to prevent inflammatory complications associated with disease progression.
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http://dx.doi.org/10.1007/s00262-020-02650-4DOI Listing
December 2020

Notch Signaling Mediates Differentiation in Barrett's Esophagus and Promotes Progression to Adenocarcinoma.

Gastroenterology 2020 08 20;159(2):575-590. Epub 2020 Apr 20.

Department of Medicine, Columbia University Irving Medical Center, New York, New York; Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York.

Background & Aims: Studies are needed to determine the mechanism by which Barrett's esophagus (BE) progresses to esophageal adenocarcinoma (EAC). Notch signaling maintains stem cells in the gastrointestinal tract and is dysregulated during carcinogenesis. We explored the relationship between Notch signaling and goblet cell maturation, a feature of BE, during EAC pathogenesis.

Methods: We measured goblet cell density and levels of Notch messenger RNAs in BE tissues from 164 patients, with and without dysplasia or EAC, enrolled in a multicenter study. We analyzed the effects of conditional expression of an activated form of NOTCH2 (pL2.Lgr5.N2IC), conditional deletion of NOTCH2 (pL2.Lgr5.N2fl/fl), or loss of nuclear factor κB (NF-κB) (pL2.Lgr5.p65fl/fl), in Lgr5 (progenitor) cells in L2-IL1B mice (which overexpress interleukin 1 beta in esophagus and squamous forestomach and are used as a model of BE). We collected esophageal and stomach tissues and performed histology, immunohistochemistry, flow cytometry, transcriptome, and real-time polymerase chain reaction analyses. Cardia and forestomach tissues from mice were cultured as organoids and incubated with inhibitors of Notch or NF-kB.

Results: Progression of BE to EAC was associated with a significant reduction in goblet cell density comparing nondysplastic regions of tissues from patients; there was an inverse correlation between goblet cell density and levels of NOTCH3 and JAG2 messenger RNA. In mice, expression of the activated intracellular form of NOTCH2 in Lgr5 cells reduced goblet-like cell maturation, increased crypt fission, and accelerated the development of tumors in the squamocolumnar junction. Mice with deletion of NOTCH2 from Lgr5 cells had increased maturation of goblet-like cells, reduced crypt fission, and developed fewer tumors. Esophageal tissues from in pL2.Lgr5.N2IC mice had increased levels of RelA (which encodes the p65 unit of NF-κB) compared to tissues from L2-IL1B mice, and we found evidence of increased NF-κB activity in Lgr5 cells. Esophageal tissues from pL2.Lgr5.p65fl/fl mice had lower inflammation and metaplasia scores than pL2.Lgr5.N2IC mice. In organoids derived from pL2-IL1B mice, the NF-κB inhibitor JSH-23 reduced cell survival and proliferation.

Conclusions: Notch signaling contributes to activation of NF-κB and regulates differentiation of gastric cardia progenitor cells in a mouse model of BE. In human esophageal tissues, progression of BE to EAC was associated with reduced goblet cell density and increased levels of Notch expression. Strategies to block this pathway might be developed to prevent EAC in patients with BE.
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http://dx.doi.org/10.1053/j.gastro.2020.04.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484392PMC
August 2020

The brain proteome profile is highly conserved between Prnp-/- and Prnp+/+ mice.

Neuroreport 2008 Jul;19(10):1027-31

Laboratory of Molecular Neuropathology, Centre of Neuropathology and Prion Research, LAFUGA, Gene Centre, LMU, Munich, Germany.

The aim of this study is to compare the proteome of Prnp-/- (Zürich I) gene-ablated mouse brains with wild-type mouse brains. Fluorescence two-dimensional-difference gel electrophoresis (DIGE) and isotope-coded protein labeling (ICPL) were applied for brain homogenates. Similar quantitative protein profiles (
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http://dx.doi.org/10.1097/WNR.0b013e3283046157DOI Listing
July 2008