Acinar ATP8b1/LPC pathway promotes macrophage efferocytosis and clearance of inflammation during chronic pancreatitis development.

Noninflammatory clearance of dying cells by professional phagocytes, termed efferocytosis, is fundamental in both homeostasis and inflammatory fibrosis disease but has not been confirmed to occur in chronic pancreatitis (CP). Here, we investigated whether efferocytosis constitutes a novel regulatory target in CP and its mechanisms. PRSS1 transgenic (PRSS1Tg) mice were treated with caerulein to mimic CP development. Phospholipid metabolite profiling and epigenetic assays were performed with PRSS1Tg CP models. The potential functions of Atp8b1 in CP model were clarified using Atp8b1-overexpressing adeno-associated virus, immunofluorescence, enzyme-linked immunosorbent assay(ELISA), and lipid metabolomic approaches. ATAC-seq combined with RNA-seq was then used to identify transcription factors binding to the Atp8b1 promoter, and ChIP-qPCR and luciferase assays were used to confirm that the identified transcription factor bound to the Atp8b1 promoter, and to identify the specific binding site. Flow cytometry was performed to analyze the proportion of pancreatic macrophages. Decreased efferocytosis with aggravated inflammation was identified in CP. The lysophosphatidylcholine (LPC) pathway was the most obviously dysregulated phospholipid pathway, and LPC and Atp8b1 expression gradually decreased during CP development. H3K27me3 ChIP-seq showed that increased Atp8b1 promoter methylation led to transcriptional inhibition. Atp8b1 complementation substantially increased the LPC concentration and improved CP outcomes. Bhlha15 was identified as a transcription factor that binds to the Atp8b1 promoter and regulates phospholipid metabolism. Our study indicates that the acinar Atp8b1/LPC pathway acts as an important "find-me" signal for macrophages and plays a protective role in CP, with Atp8b1 transcription promoted by the acinar cell-specific transcription factor Bhlha15. Bhlha15, Atp8b1, and LPC could be clinically translated into valuable therapeutic targets to overcome the limitations of current CP therapies.

St13 protects against disordered acinar cell arachidonic acid pathway in chronic pancreatitis.

BACKGROUND: Early diagnosis and treatment of chronic pancreatitis (CP) are limited. In this study, St13, a co-chaperone protein, was investigated whether it constituted a novel regulatory target in CP. Meanwhile, we evaluated the value of micro-PET/CT in the early diagnosis of CP. METHODS: Data from healthy control individuals and patients with alcoholic CP (ACP) or non-ACP (nACP) were analysed. PRSS1 transgenic mice (PRSS1Tg) were treated with ethanol or caerulein to mimic the development of ACP or nACP, respectively. Pancreatic lipid metabolite profiling was performed in human and PRSS1Tg model mice. The potential functions of St13 were investigated by crossing PRSS1Tg mice with St13-/- mice via immunoprecipitation and lipid metabolomics. Micro-PET/CT was performed to evaluate pancreatic morphology and fibrosis in CP model. RESULTS: The arachidonic acid (AA) pathway ranked the most commonly dysregulated lipid pathway in ACP and nACP in human and mice. Knockout of St13 exacerbated fatty replacement and fibrosis in CP model. Sdf2l1 was identified as a binding partner of St13 as it stabilizes the IRE1α-XBP1s signalling pathway, which regulates COX-2, an important component in AA metabolism. Micro-PET/CT with 68Ga-FAPI-04 was useful for evaluating pancreatic morphology and fibrosis in CP model mice 2 weeks after modelling. CONCLUSION: St13 is functionally activated in acinar cells and protects against the cellular characteristics of CP by binding Sdf2l1, regulating AA pathway. 68Ga-FAPI-04 PET/CT may be a very valuable approach for the early diagnosis of CP. These findings thus provide novel insights into both diagnosis and treatment of CP.

Roles and Clinical Significances of ATF6, EMC6, and APAF1 in Prognosis of Pancreatic Cancer.

Background: Pancreatic cancer (PC) is prevalent among malignant tumors with poor prognosis and lacks efficient therapeutic strategies. Endoplasmic reticulum (ER) stress and apoptosis are associated with chronic inflammation and cancer progression. However, the prognostic value of ER stress-related, and apoptosis-related genes in PC remains to be further elucidated. Our study aimed at confirming the prognostic values of the ER stress-related genes, ATF6, EMC6, XBP1, and CHOP, and the apoptosis-related gene, APAF1, in PC patients. Methods: Gene Expression Profiling Interactive Analysis 2 (GEPIA2) was used to evaluate prognosis value of ATF6, EMC6, XBP1, CHOP, and APAF1 in PC. Clinical data from 69 PC patients were retrospectively analyzed. Immunohistochemistry, Western blotting, and qRT-PCR were used for the assessment of gene or protein expression. The cell counting kit-8 (CCK-8) and the Transwell invasion assays were, respectively, used for the assessment of the proliferative and invasive abilities of PC cells. The prognostic values of ATF6, XBP1, CHOP, EMC6, and APAF1 in PC patients were evaluated using Kaplan-Meier and Cox regression analyses. Results: XBP1 and CHOP expressions were not associated with PC recurrence-free survival (RFS), overall survival (OS) and disease-specific survival (DSS). ATF6 upregulation and EMC6 and APAF1 downregulations significantly correlated with the poor RFS, OS, and DSS of PC patients. ATF6 promoted PC cell proliferation and invasion, while EMC6 and APAF1 inhibited these events. Conclusion: ATF6 upregulation and EMC6 and APAF1 downregulations may be valid indicators of poor prognosis of PC patients. Moreover, ATF6, EMC6, and APAF1 may constitute potential therapeutic targets in PC patients.

EMC6 regulates acinar apoptosis via APAF1 in acute and chronic pancreatitis.

Treatment of acute pancreatitis (AP) and chronic pancreatitis (CP) remains problematic due to a lack of knowledge about disease-specific regulatory targets and mechanisms. The purpose of this study was to screen proteins related to endoplasmic reticulum (ER) stress and apoptosis pathways that may play a role in pancreatitis. Human pancreatic tissues including AP, CP, and healthy volunteers were collected during surgery. Humanized PRSS1 (protease serine 1) transgenic (PRSS1Tg) mice were constructed and treated with caerulein to mimic the development of human AP and CP. Potential regulatory proteins in pancreatitis were identified by proteomic screen using pancreatic tissues of PRSS1Tg AP mice. Adenoviral shRNA-mediated knockdown of identified proteins, followed by functional assays was performed to validate their roles. Functional analyses included transmission electron microscopy for ultrastructural analysis; qRT-PCR, western blotting, co-immunoprecipitation, immunohistochemistry, and immunofluorescence for assessment of gene or protein expression, and TUNEL assays for assessment of acinar cell apoptosis. Humanized PRSS1Tg mice could mimic the development of human pancreatic inflammatory diseases. EMC6 and APAF1 were identified as potential regulatory molecules in AP and CP models by proteomic analysis. Both EMC6 and APAF1 regulated apoptosis and inflammatory injury in pancreatic inflammatory diseases. Moreover, APAF1 was regulated by EMC6, induced apoptosis to injure acinar cells and promoted inflammation. In the progression of pancreatitis, EMC6 was activated and then upregulated APAF1 to induce acinar cell apoptosis and inflammatory injury. These findings suggest that EMC6 may be a new therapeutic target for the treatment of pancreatic inflammatory diseases.

ATF6 aggravates acinar cell apoptosis and injury by regulating p53/AIFM2 transcription in Severe Acute Pancreatitis.

Background: There is no curative therapy for severe acute pancreatitis (SAP) due to poor understanding of its molecular mechanisms. Endoplasmic reticulum (ER) stress is involved in SAP and increased expression of ATF6 has been detected in SAP patients. Here, we aimed to investigate the role of ATF6 in a preclinical SAP mouse model and characterize its regulatory mechanism. Methods: Pancreatic tissues of healthy and SAP patients were collected during surgery. Humanized PRSS1 transgenic mice were treated with caerulein to mimic the SAP development, which was crossed to an ATF6 knockout mouse line, and pancreatic tissues from the resulting pups were screened by proteomics. Adenovirus-mediated delivery to the pancreas of SAP mice was used for shRNA-based knockdown or overexpression. The potential functions and mechanisms of ATF6 were clarified by immunofluorescence, immunoelectron microscopy, Western blotting, qRT-PCR, ChIP-qPCR and luciferase reporter assay. Results: Increased expression of ATF6 was associated with elevated apoptosis, ER and mitochondrial disorder in pancreatic tissues from SAP patients and PRSS1 mice. Knockout of ATF6 in SAP mice attenuated acinar injury, apoptosis and ER disorder. AIFM2, known as a p53 target gene, was identified as a downstream regulatory partner of ATF6, whose expression was increased in SAP. Functionally, AIFM2 could reestablish the pathological disorder in SAP tissues in the absence of ATF6. p53 expression was also increased in SAP mice, which was downregulated by ATF6 knockout. p53 knockout significantly suppressed acinar apoptosis and injury in SAP model. Mechanistically, ATF6 promoted AIFM2 transcription by binding to p53 and AIFM2 promoters. Conclusion: These results reveal that ATF6/p53/AIFM2 pathway plays a critical role in acinar apoptosis during SAP progression, highlighting novel therapeutic target molecules for SAP.

Viral hepatitis B and C infections increase the risks of intrahepatic and extrahepatic cholangiocarcinoma: Evidence from a systematic review and meta-analysis.

BACKGROUND/AIMS: Previous study has shown a positive relationship between the hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and cholangiocarcinoma (CCA); however, their correlation with different anatomical sites of CCA (i.e. ICC and ECC) has not been revealed. This study aims to evaluate the association of HBV or HCV infection with CCA, including the intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC), and to determine the roles of α-1 fetoprotein (AFP), CA19-9, and lymph node involvement in CCA with HBV infection. MATERIALS AND METHODS: Relevant studies published between 2004 and 2016 were systematically searched and retrieved from PubMed, SpringerLink, and Science Direct using key terms such as "cholangiocarcinoma", "bile duct cancer", "extrahepatic cholangiocarcinoma", and "intrahepatic cholangiocarcinoma". The demographic, clinical, and laboratory data were extracted from the included studies, and the meta-analysis was performed using RevMan and STATA 11.0 software. RESULTS: A total of 13 studies with CCA matched the inclusion criteria in this meta-analysis, including 7,113 CCA patients and 24,763 controls. This meta-analysis showed that the HBV or HCV infections can significantly increase the risk of CCA, including ICC and ECC. In addition, the higher levels of AFP, lower levels of CA19-9, and lymph node involvement were detected in the CCA patients with HBV infection as compared to those without. CONCLUSION: The HBV and HCV infections significantly increased the risk of CCA, as well as ICC and ECC. The involvement of AFP, CA19-9, and lymph nodes may play an important role in the diagnosis of CCA.

Risk factors for the concomitant occurrence of alcoholic chronic pancreatitis and alcoholic liver cirrhosis: a 10-years cohort study at a tertiary hospital in China.

OBJECTIVE: Concomitant occurrence of alcoholic chronic pancreatitis (ACP) and alcoholic liver cirrhosis (ALC) is rare with few reported cases. The present study aimed to identify the potential risk factors of chronic pancreatitis (CP) and liver cirrhosis (LC) in ALC patients and ACP patients, respectively. METHODS: A retrospective analysis was performed on 536 patients with CP and 647 ALC patients without CP (Group A). Among the 536 CP patients, 213 ACP cases were divided into two groups: ACP with LC (Group B, n = 52) and ACP without LC (Group C, n = 161). A comparison between Group A and B was carried out to identify the potential risk factors of CP in ALC patients, while Group B and C were compared to determine the independent risk factors of LC in ACP patients. RESULTS: Concomitant occurrence of ACP and ALC accounted for 24.4% (52/213) in this cohort. Significant risk factors for CP in ALC patients included smoking [odds ratio (OR), 2.557; 95% confidence interval (CI): 1.531-5.489; P = 0.003] and multiple bouts of acute pancreatitis (OR, 4.813; 95% CI: 3.625-12.971; P < 0.001). Hepatitis B virus (HBV) infection (OR, 4.237; 95% CI: 1.742-7.629; P = 0.012) was the only independent risk factor associated with LC in ACP patients. CONCLUSION: HBV infection exacerbated liver damage in ACP patients. Alcoholic patients who smoked and suffered from ongoing bouts of acute pancreatitis are prone to develop CP.

ATF6 regulates the development of chronic pancreatitis by inducing p53-mediated apoptosis.

Chronic pancreatitis (CP) is a progressive, recurrent inflammatory disorder of the pancreas. Initiation and progression of CP can result from serine protease 1 (PRSS1) overaccumulation and the ensuing endoplasmic reticulum (ER) stress. However, how ER stress pathways regulate the development and progression of CP remains poorly understood. In the present study we aimed to elucidate the ER stress pathway involved in CP. We found high expression of the ER stress marker genes ATF6, XBP1, and CHOP in human clinical specimens. A humanized PRSS1 transgenic mouse was established and treated with caerulein to mimic the development of CP, as evidenced by pathogenic alterations, collagen deposition, and increased expression of the inflammatory factors IL-6, IL-1ß, and TNF-α. ATF6, XBP1, and CHOP expression levels were also increased during CP development in this model. Acinar cell apoptosis was also significantly increased, accompanied by upregulated p53 expression. Inhibition of ATF6 or p53 suppressed the expression of inflammatory factors and progression of CP in the mouse model. Finally, we showed that p53 expression could be regulated by the ATF6/XBP1/CHOP axis to promote the development of CP. We therefore conclude that ATF6 signalling regulates CP progression by modulating pancreatic acinar cell apoptosis, which provides a target for ER stress-based diagnosis and treatment of CP.

Identification of risk factors for pancreatic pseudocysts formation, intervention and recurrence: a 15-year retrospective analysis in a tertiary hospital in China.

BACKGROUND: Pancreatic pseudocyst (PPC) is a common complication of acute and chronic pancreatitis. To our knowledge no study has systematically reported the risk factors for the formation, intervention and recurrence of PPC. Therefore, the present study aimed to investigate the potential risk factors for PPC, with regards to its formation, intervention and recurrence. METHODS: A database containing 5106 pancreatitis patients was retrospectively analyzed. As a result, a total of 4379 eligible patients were identified and divided into 2 groups: PPC group (group A, n = 759) and non-PPC group (group B, n = 3620). The PPC group was subdivided into 2 groups: intervention PPC (group C, n = 347) and resolution PPC (group D, n = 412). The differences in surgical complication and recurrence rates were compared among 347 PPC patients receiving different interventions, including surgical, endoscopic and percutaneous drainages. Furthermore, group C was subdivided into 2 groups: recurrent PPC (group E, n = 34) and non-recurrent PPC (group F, n = 313). All possible risk factors for PPC formation, intervention and recurrence were determined by multivariate regression analysis. RESULTS: In this study, PPC was developed in 17.3% (759/4379) of pancreatitis patients. The significant risk factors for PPC formation included alcoholic pancreatitis (OR, 6.332; 95% CI, 2.164-11.628; p = 0.031), chronic pancreatitis (CP) (OR, 5.822; 95% CI, 1.921-10.723; p = 0.006) and infected pancreatic necrosis (OR, 4.253; 95% CI, 3.574-7.339; p = 0.021). Meanwhile, the significant risk factors of PPC patients who received intervention were alcoholic pancreatitis (OR, 7.634; 95% CI, 2.125-13.558; p = 0.016), size over 6 cm (OR, 8.834; 95% CI, 2.017-16.649; p = 0.002) and CP (OR, 4.782; 95% CI, 1.897-10.173; p = 0.038). In addition, the recurrence rate in PPC patients treated with percutaneous drainage was found to be the highest (16.3%) among the three intervention groups. Furthermore, percutaneous drainage was the only risk factor of PPC recurrence (OR, 7.812; 95% CI, 3.109-23.072; p = 0.013) identified from this retrospective cohort study. CONCLUSIONS: Alcoholic pancreatitis and CP are the main risk factors for PPC formation and intervention, but not PPC recurrence. A higher recurrence rate is found in PPC patients treated with percutaneous drainage, as compared to endoscopic and surgical interventions.