Project description:A frequently used experimental model of chronic pancreatitis (PC) recapitulating human disease is repeated injection of cerulein to mice. We found that two common substrains of C57BL/6 , C56BL/6J (Jackson) and C57BL/6NHsd (Harlan), exhibit different degree of CP with C57BL/6J beeing more susceptible to repetitive cerulein induced CP. The goal of this study was to identify genes associated with CP and also to identify genes differentially regulated between two substrains as candidates for the CP progression. RNAs were isolated from the pancreas of 8-week old Jackson and Harlan mice after the cerulein induction of chronic pancreatitis and hybridized on Affymetrix microarrays. Saline injected mice were used as controls. Three mice from each experimental and control groups were used in the experiment.
Project description:RNA expression from whole pancreatic tissue was assessed by RNA-seq following 4 hours into cerulein-induced pancreatitis in mice lacking the transcription factor ATF3 or congenic C57Bl6 mice. Three mice were used for each group and sequncing performed by Toronto Genomics Centre.
Project description:Background & Aims Pancreatitis is an inflammatory disease of the exocrine pancreas and a known risk factor for pancreatic ductal adenocarcinoma (PDAC). Previously, we identified HMG- box transcription factor 1 (HBP1) as a potential master transcription factor (TF) in the early progression of PDAC, with its expression associated with poor patient survival, underscoring its significance in pancreatic disease. However, the functional role of HBP1 in the onset and progression of acute pancreatitis (AP) remains unknown. Methods We examined HBP1 expression in human pancreatitis samples and a cerulein-induced AP mouse model. Pancreatic-specific conditional HBP1 knockout mice, with or without an oncogenic Kras mutation, were generated and compared to their littermate controls. Spatial transcriptomics and multiplexed protein assays, histological analysis, and immunostaining were utilized to characterize pathological changes. Findings from mouse models were validated using inducible HBP1-overexpressing human pancreatic ductal epithelial cells. Results HBP1 was upregulated in pancreatic exocrine cells in human chronic pancreatitis and mouse acute pancreatitis, with its expression in human chronic pancreatitis correlating with cancer presence. Pancreatic HBP1 ablation disrupted acinar homeostasis by impairing autophagic flux and exacerbating inflammation following injury. In the presence of oncogenic KRAS, HBP1 ablation delayed the formation of pancreatic intraepithelial neoplasia (PanIN), the precursor to PDAC, and slowed its progression to higher-grade lesions. Conclusions HBP1 upregulation in pancreatitis mitigates pancreatic inflammatory injury; however, in the presence of oncogenic KRAS, it facilitates PanIN progression. Thus, HBP1 serves as a critical regulator in both pancreatitis and early pancreatic neoplasia, representing a potential therapeutic target for intervening pancreatitis and PanIN progression.
Project description:A frequently used experimental model of chronic pancreatitis (PC) recapitulating human disease is repeated injection of cerulein to mice. We found that two common substrains of C57BL/6 , C56BL/6J (Jackson) and C57BL/6NHsd (Harlan), exhibit different degree of CP with C57BL/6J beeing more susceptible to repetitive cerulein induced CP. The goal of this study was to identify genes associated with CP and also to identify genes differentially regulated between two substrains as candidates for the CP progression.
Project description:We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genomic stability and its loss confers sensitivity to radio- and platinum-based therapies.
Project description:The canonical NF-κB pathway is active in 70% of all pancreatic cancer cases and NF-κB Essential Modulator (NEMO) is essential for the activation of this pathway. In our study, we used KC mice, which express the oncogenic KRAS and develop precancerous lesions termed Pancreatic Intraepithelial Neoplasias (PanINs), and KNeC mice, which express the oncogenic KRAS and have NEMO deleted in their pancreatic cells. These mice were injected with cerulein to promote the development of pancreatitis (cerulein dosage= 50μg/kg). Cerulein was injected at 8 hourly intervals for 2 days in total. The first injection day was when mice reached their sixth week of age and the second injection day was 3 days after the first injection day. Both KC and KNeC mice developed PanINs. At the age of 10 months, pancreata of KC and KNeC mice were analyzed. Using laser capture microdissection, PanINs from both groups were excised and their transcriptome was analyzed though RNA-seq.
Project description:To determine the molecular basis of gene regulation in pancreatic ductal epithelial cells, we developed methods for the isolation of this cell population during mouse development and normal adult homeostasis, as well as in conditions with ductal features (acinar-to-ductal metaplasia (ADM), pancreatic intraepithelial neoplasia (PanIN) and pancreatic ductal adenocarcinoma (PDAC)). Our technique utilizes the specificity of Dolichos biflorus Agglutinin (DBA) lectin marking the entire normal ductal tree, including terminal intercalated ducts (putative sites of stem or progenitor cells) and ductal structures in ADM and PanIN. We used ferromagnetic-labeled DBA lectin to isolate ductal structures. Ductal cells were isolated under the following conditions: (1) Embryonic Development in wild type mice: E14.5, E15.5, E16.5, and postnatal day 1 (P1); (2) Injury and regeneration (pancreatitis) 0, 1, 3, 5 days following cerulein-induced acute pancreatitis. Cerulein is a cholecystokinin analog which produces a self-limited pancreatitis with injury and subsequent regeneration and repair, completed five days after insult; and (3) Pdx1-Cre;LSL-KrasG12D/+ mice aged 10 and 20 weeks that harbor PanIN lesions and a subset develop PDAC. Ductal/PanIN cells were isolated from these mice and appropriate control mice (Pdx1-Cre;Kras+/+).
Project description:Pancreatitis is triggered by environmental or cellular stress and is the leading contributor to pancreatic ductal adenocarcinoma. Altered gene expression in response to acinar cell stress determines the severity and duration of pancreatitis. However, it is unclear what factors contribute to this phenomenon. Here, we define a novel role for Activating Transcription Factor 3 (ATF3) during pancreatic injury. ATF3, a key mediator in the unfolded protein response, is robustly expressed in acinar cells during pancreatitis. Targeted deletion of Atf3 altered the molecular response to injury, with Atf3-/- acinar cells maintaining cell organization in response to cerulein, a well-established inducer of pancreatitis. Characterization of the mechanism using chromatin immunoprecipitation followed by Next Generation sequencing (ChIP-seq) identified 11,771 enrichment spots for ATF3, with known transcriptional start sites for >3,000 genes within 5 kb of ATF3 enrichment. Gene ontology analysis revealed a significant representation of ATF3 enrichment to genes affecting cell organization, including Mist1, a molecule required for establishing acinar cell organization. We confirmed a direct interaction of ATF3 to the Mist1 promoter during pancreatitis, and showed that ATF3 is required for altered Mist1 expression in response to injury. Finally, we demonstrate that ATF3 repression of Mist1 involves HDAC5. These findings suggest that ATF3 is a key transcriptional regulator during pancreatitis and promotes loss of the mature acinar cell phenotype in response to pancreatic injury. Two samples were produced from male mice 4 hours after CIP initiation from intraparitoneal injections of cerulein, a ChIP sample using an ATF3 antibody and an IP control.
Project description:Pancreas tissue derived from mice with intraperitoneal injection of saline, cerulein or polyI:C plus cerulein, total RNA was extracted and deep sequenced to compare the gene expression profiles among control, acute pancreatitis and intervention of polyI:C on acute pancreatitis.