Refine
Document Type
- Article (15)
- Doctoral Thesis (1)
Has Fulltext
- yes (16)
Is part of the Bibliography
- no (16)
Keywords
- - (8)
- acute pancreatitis (4)
- DNA repair (2)
- PDAC (2)
- Pancreatic cancer (2)
- bile acids (2)
- chronic pancreatitis (2)
- experimental pancreatitis (2)
- immune response (2)
- 6606PDA (1)
Institute
- Kliniken und Polikliniken für Innere Medizin (8)
- Klinik und Poliklinik für Innere Medizin Abt. Gastroenterologie, Endokrinologie und Ernährungsmedizin (5)
- Institut für Diagnostische Radiologie und Neuroradiologie (1)
- Institut für Pathologie (1)
- Klinik für Herz-, Thorax- und Gefäßchirurgie - Klinikum Karlsburg (1)
Publisher
- Frontiers Media S.A. (4)
- MDPI (3)
- S. Karger AG (3)
- Nature Publishing Group (2)
- BMJ Publishing Group (1)
- BioMed Central (BMC) (1)
- Elsevier (1)
Objective
Acute pancreatitis (AP) is an inflammatory disorder, the severe form of which is burdened with multi-organ dysfunction and high mortality. The pathogenesis of life –threatening organ complications, such as respiratory and renal failure, is unknown.
Design
Organ dysfunction was investigated in a mouse model of AP. The influence of monocytes and neutrophils on multi organ dysfunction syndrome (MODS) was investigated in vivo by antibody depletion. Using real-time-fluorescence and deformability-cytometry (RT-DC) analysis we determined the mechanical properties of neutrophils and monocytes during AP. Furthermore, blood samples of pancreatitis patients were used to characterize severity-dependent chemokine profiles according to the revised Atlanta classification.
Results
Similar to AP in humans, severe disease in the mouse model associates with organ dysfunction mainly of lung and kidney, which is triggered by a mobilisation of Ly6g-/CD11b+/Ly6c hi monocytes, but not of Ly6g+/CD11b+ neutrophils. Monocyte depletion by anti-CCR2 antibody treatment ameliorated lung function (oxygen consumption) without interfering with the systemic immune response. RT-DC analysis of circulation monocytes showed a significant increase in cell size during SAP, but without a compensatory increase in elasticity. Patient chemokine profiles show a correlation of AP severity with monocyte attracting chemokines like MCP-1 or MIG and with leukocyte mobilisation.
Conclusion
In AP, the physical properties of mobilized monocytes, especially their large size, result in an obstruction of the fine capillary systems of the lung and of the kidney glomeruli. A selective depletion of monocytes may represent a treatment strategy for pancreatitis as well as for other inflammation-related disorders.
Objective: In acute pancreatitis (AP), bacterial translocation and subsequent infection of pancreatic necrosis are the main risk factors for severe disease and late death. Understanding how immunological host defence mechanisms fail to protect the intestinal barrier is of great importance in reducing the mortality risk of the disease. Here, we studied the role of the Treg/Th17 balance for maintaining the intestinal barrier function in a mouse model of severe AP.
Design: AP was induced by partial duct ligation in C57Bl/6 or DEREG mice, in which regulatory T-cells (Treg) were depleted by intraperitoneal injection of diphtheria toxin. By flow cytometry, functional suppression assays and transcriptional profiling we analysed Treg activation and characterised T-cells of the lamina propria as well as intraepithelial lymphocytes (IELs) regarding their activation and differentiation. Microbiota composition was examined in intestinal samples as well as in murine and human pancreatic necrosis by 16S rRNA gene sequencing.
Results: The prophylactic Treg-depletion enhanced the proinflammatory response in an experimental mouse model of AP but stabilised the intestinal immunological barrier function of Th17 cells and CD8+/γδTCR+ IELs. Treg depleted animals developed less bacterial translocation to the pancreas. Duodenal overgrowth of the facultative pathogenic taxa Escherichia/Shigella which associates with severe disease and infected necrosis was diminished in Treg depleted animals.
Conclusion: Tregs play a crucial role in the counterbalance against systemic inflammatory response syndrome. In AP, Treg-activation disturbs the duodenal barrier function and permits translocation of commensal bacteria into pancreatic necrosis. Targeting Tregs in AP may help to ameliorate the disease course.
Background/Aims: To develop a clinically relevant immunocompetent murine model to study pancreatic cancer using two different syngeneic pancreatic cancer cell lines and to assess MRI for its applicability in this model. Methods: Two cell lines, 6606PDA and Panc02, were employed for the experiments. Cell proliferation and migration were monitored in vitro. Matrigel™ was tested for its role in tumor induction. Tumor cell growth was assessed after orthotopic injection of tumor cells into the pancreatic head of C57/BL6 mice by MRI and histology. Results: Proliferation and migration of Panc02 were significantly faster than those of 6606PDA. Matrigel did not affect tumor growth/migration but prevented tumor cell spread after injection thus avoiding undesired peritoneal tumor growth. MRI could reliably monitor longitudinal tumor growth in both cell lines: Panc02 had a more irregular finger-like growth, and 6606PDA grew more spherically. Both tumors showed local invasiveness. Histologically, Panc02 showed a sarcoma-like undifferentiated growth pattern, whereas 6606PDA displayed a moderately differentiated glandular tumor growth. Panc02 mice had a significantly shorter (28 days) survival than 6606PDA mice (50 days). Conclusion: This model closely mimics human pancreatic cancer. MRI was invaluable for longitudinal monitoring of tumor growth thus reducing the number of mice required. Employing two different cell lines, this model can be used for various treatment and imaging studies.
Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers. Acquired inherited and/or somaticmutations drive its development. In order to prevent the formation of these mutations, precise and immediaterepair of any DNA damage is indispensable. Non-homologous end-joining (NHEJ) is the key mechanism of DNAdouble-strand break repair. Here, we report that miR-502 targets two components in pancreatic cell lines, Ku70and XLF of the C-NHEJ. Interestingly, we also observed an attenuated cell cycle response to gamma ionizingradiation (γ-IR) via diminished phosphorylation of checkpoint kinase 1 (Chk1) on serine 345 in these cell lines.Altogether, pancreatic cells showed increased susceptibility toγ-IR via direct inhibition of DNA double-strandbreak repair and attenuation of the cell cycle response.
Plasma Metabolome Profiling Identifies Metabolic Subtypes of Pancreatic Ductal Adenocarcinoma
(2021)
Simple Summary
Pancreatic ductal adenocarcinoma (PDAC) is one of the most deadly cancers worldwide. The occurrence of oncogenic KRAS mutations is considered a signature event in PDAC, leading to genomic instability. The aim of our study was to evaluate the impact of the oncogenic KRAS G12D mutation on the activity of the error-prone alt-EJ repair mechanism, and to investigate the potential role of Polθ in the development of pancreatic cancer. We found that oncogenic KRAS increases the expression of key alt-EJ proteins in a mouse and human PDAC model. Using TLR assay, we also found increased alt-EJ activity in mouse and human cell lines upon the expression of KRAS D12D. The inactivation/impairment of alt-EJ by polymerase theta (Polθ) depletion delays the development of pancreatic cancer and prolongs the survival of experimental mice, though it does not prevent the PDAC development, which leads to full-blown PDAC with disseminated metastasis. Our studies provide a high-value target as a novel therapeutic candidate for the treatment of pancreatic and other cancers.
Abstract
Pancreatic ductal adenocarcinoma (PDAC), due to its genomic heterogeneity and lack of effective treatment, despite decades of intensive research, will become the second leading cause of cancer-related deaths by 2030. Step-wise acquisition of mutations, due to genomic instability, is considered to drive the development of PDAC; the KRAS mutation occurs in 95 to 100% of human PDAC, and is already detectable in early premalignant lesions designated as pancreatic intraepithelial neoplasia (PanIN). This mutation is possibly the key event leading to genomic instability and PDAC development. Our study aimed to investigate the role of the error-prone DNA double-strand breaks (DSBs) repair pathway, alt-EJ, in the presence of the KRAS G12D mutation in pancreatic cancer development. Our findings show that oncogenic KRAS contributes to increasing the expression of Polθ, Lig3, and Mre11, key components of alt-EJ in both mouse and human PDAC models. We further confirm increased catalytic activity of alt-EJ in a mouse and human model of PDAC bearing the KRAS G12D mutation. Subsequently, we focused on estimating the impact of alt-EJ inactivation by polymerase theta (Polθ) deletion on pancreatic cancer development, and survival in genetically engineered mouse models (GEMMs) and cancer patients. Here, we show that even though Polθ deficiency does not fully prevent the development of pancreatic cancer, it significantly delays the onset of PanIN formation, prolongs the overall survival of experimental mice, and correlates with the overall survival of pancreatic cancer patients in the TCGA database. Our study clearly demonstrates the role of alt-EJ in the development of PDAC, and alt-EJ may be an attractive therapeutic target for pancreatic cancer patients.
Die Rolle des Immunsystems im Verlauf der Pankreatitis ist ein Zusammenspiel verschiedener Faktoren. Generell ist festzustellen das infiltrierende Leukozyten im Verlauf der Pankreatitis einen direkten Einfluss sowohl auf den pankreatischen Schaden als auch auf den systemischen Schaden haben. Es konnte gezeigt werden, dass die Pankreatitis in CD18 defizienten Mäusen zeitlich einen anderen Verlauf nimmt im Vergleich zu den Kontrolltieren. Mit der Verschiebung der Infiltration der Leukozyten verschiebt sich auch die Proteaseaktivierung, bzw. die Entstehung des pankreatischen Schadens. Neutrophile als auch Makrophagen/ Monozyten transmigrieren beide CD18 abhängig in das Pankreas und sind in den späteren Zeitpunkten für die Proteaseaktivierung in gleichem Maße verantwortlich. Die Depletion der Neutrophilen Granulozyten als auch die Depletion von Makrophagen/Monozyten vor Induktion der Pankreatitis führt in gleicher Weise zu einer Verminderung des Schweregrades der Erkrankung in den Tieren. Nicht nur in vivo konnte ein Effekt von Leukozyten auf den Verlauf der Pankreatitis gezeigt werden, auch in vitro zeigen Leukozyten einen direkten Effekt auf den Azinuszellschaden sowie auf die intrazelluläre Proteaseaktivierung. Makrophagen als auch Neutrophile zeigen diesen direkten Effekt auf Azinuszellen. Die Depletion von CD4 positiven T-Zellen führt zu einer verminderten proinflamatorischen Antwort in den Tieren welche in einem milderen Verlauf der Pankreatitis resultiert, da weniger Zellen des angeborenen Immunsystems in den Pankreas transmigrieren. Ein von Leukozyten vermittelter Mechanismus der zu einem erhöhten Azinuszellschaden als auch zu einem Anstieg der Proteaseaktivierung führt ist die Freisetzung von TNFα. In isolierten Azinuszellen konnte gezeigt werden das TNFα einen direkten Effekt auf das Überleben der Zellen hat und zu einer Cathepsin B vermittelten Aktivierung von Trypsinogen führt. Cathepsin B knockout Tiere reagieren nicht auf eine Stimulation durch TNFα mit einer Aktivierung von Trypsinogen oder einer Azinuszellnekrose. Dies stellt eine therapeutische Möglichkeit in Aussicht. Durch den Einsatz eines TNFα spezifischen Antikörpers konnte der Azinuszellschaden der durch Leukozyten vermittelt wird als auch die Cathepsin B vermittelte Proteaseaktivierung signifikant gesenkt werden. Dies stellt eine neue Möglichkeit der Therapie der chronischen Pankreatitis dar, da sie in gleicher Weise wie der Morbus Crohn oder die rheumatoide Arthritis als chronische Entzündungsreaktion mit Hilfe von TNFα inhibierenden Antikörpern behandelt werden könnte.
Background: Abdominal surgery is frequently followed by immune dysfunction usually lasting for several days. This is especially important in cases with tumour diseases as an intact immune function is essential in this situation. Therefore, we analysed the outcome of tumour-bearing mice in a mouse model of surgically induced immune dysfunction (SID). Methods: In male C57BL/6 mice, a pancreatic tumour was implanted orthotopically. Following tumour implantation, the model of SID was applied. The control groups were either laparotomised or underwent no surgical procedure. The survival rate was determined by observation for >60 days. The tumour growth progress was imaged by a 7-tesla small animal MRI. Results: On day 60 after tumour implantation, the survival rate in SID mice was reduced to 41%. In the laparotomised group, 81% of mice survived, while the control group had a survival rate of 75%. These differences were significant (SID vs. control: p < 0.02, and SID vs. laparotomy: p < 0.002). The tumour volume was not influenced by the degree of surgical trauma. Conclusion: In pancreatic cancer, the SID model is ideally suited to investigate the influence of SID on this tumour entity.
Chronic pancreatitis (CP) is characterized by chronic inflammation and the progressive fibrotic replacement of exocrine and endocrine pancreatic tissue. We identify Treg cells as central regulators of the fibroinflammatory reaction by a selective depletion of FOXP3-positive cells in a transgenic mouse model (DEREG-mice) of experimental CP. In Treg-depleted DEREG-mice, the induction of CP results in a significantly increased stroma deposition, the development of exocrine insufficiency and significant weight loss starting from day 14 after disease onset. In CP, FOXP3+CD25+ Treg cells suppress the type-2 immune response by a repression of GATA3+ T helper cells (Th2), GATA3+ innate lymphoid cells type 2 (ILC2) and CD206+ M2-macrophages. A suspected pathomechanism behind the fibrotic tissue replacement may involve an observed dysbalance of Activin A expression in macrophages and of its counter regulator follistatin. Our study identified Treg cells as key regulators of the type-2 immune response and of organ remodeling during CP. The Treg/Th2 axis could be a therapeutic target to prevent fibrosis and preserve functional pancreatic tissue.
Acute pancreatitis (AP) is a major, globally increasing gastrointestinal disease and a biliary origin is the most common cause. However, the effects of bile acids (BAs), given systemically, on the pancreas and on disease severity remains elusive. In this study, we have investigated the roles of different circulating BAs in animal models for AP to elucidate their impact on disease severity and the underlying pathomechanisms. BAs were incubated on isolated acini and AP was induced through repetitive injections of caerulein or L-arginine; pancreatic duct ligation (PDL); or combined biliopancreatic duct ligation (BPDL). Disease severity was assessed using biochemical and histological parameters. Serum cholecystokinin (CCK) concentrations were determined via enzyme immunoassay. The binding of the CCK1 receptor was measured using fluorescence-labeled CCK. In isolated acini, hydrophobic BAs mitigated the damaging effects of CCK. The same BAs further enhanced pancreatitis in L-arginine- and PDL-based pancreatitis, whereas they ameliorated pancreatic damage in the caerulein and BPDL models. Mechanistically, the binding affinity of the CCK1 receptor was significantly reduced by hydrophobic BAs. The hydrophobicity of BAs and the involvement of CCK seem to be relevant in the course of AP. Systemic BAs may affect the severity of AP by interfering with the CCK1 receptor.