The role of the carboxyl ester lipase (CEL) gene in pancreatic disease

High-density generation of spatial transcriptomics with STAGE

Spatial transcriptome technologies have enabled the measurement of gene expression while maintaining spatial location information for deciphering the spatial heterogeneity of biological tissues. However, they were heavily limited by the sparse spatial resolution and low data quality. To this end, we develop a spatial location-supervised auto-encoder generator STAGE for generating high-density spatial transcriptomics (ST). STAGE takes advantage of the customized supervised auto-encoder to learn continuous patterns of gene expression in space and generate high-resolution expressions for given spatial coordinates. STAGE can improve the low quality of spatial transcriptome data and smooth the generated manifold of gene expression through the de-noising function on the latent codes of the auto-encoder. Applications to four ST datasets, STAGE has shown better recovery performance for down-sampled data than existing methods, revealed significant tissue structure specificity, and enabled robust identification of spatially informative genes and patterns. In addition, STAGE can be extended to three-dimensional (3D) stacked ST data for generating gene expression at any position between consecutive sections for shaping high-density 3D ST configuration.

Common single-base insertions in the VNTR of the carboxyl ester lipase (CEL) gene are benign and also likely to arise somatically in the exocrine pancreas

The CEL gene encodes carboxyl ester lipase, a pancreatic digestive enzyme. CEL is extremely polymorphic due to a variable number tandem repeat (VNTR) located in the last exon. Single-base deletions within this VNTR cause the inherited disorder MODY8, whereas little is known about VNTR single-base insertions in pancreatic disease. We therefore mapped CEL insertion variants (CEL-INS) in 200 Norwegian patients with pancreatic neoplastic disorders. Twenty-eight samples (14.0%) carried CEL-INS alleles. Most common were insertions in repeat 9 (9.5%), which always associated with a VNTR length of 13 repeats. The combined INS allele frequency (0.078) was similar to that observed in a control material of 416 subjects (0.075). We performed functional testing in HEK293T cells of a set of CEL-INS variants, in which the insertion site varied from the first to the 12th VNTR repeat. Lipase activity showed little difference among the variants. However, CEL-INS variants with insertions occurring in the most proximal repeats led to protein aggregation and endoplasmic reticulum stress, which upregulated the unfolded protein response. Moreover, by using a CEL-INS-specific antibody, we observed patchy signals in pancreatic tissue from humans without any CEL-INS variant in the germline. Similar pancreatic staining was seen in knock-in mice expressing the most common human CEL VNTR with 16 repeats. CEL-INS proteins may therefore be constantly produced from somatic events in the normal pancreatic parenchyma. This observation along with the high population frequency of CEL-INS alleles strongly suggests that these variants are benign, with a possible exception for insertions in VNTR repeats 1-4.

Construction and Analysis of a Mitochondrial Metabolism-Related Prognostic Model for Breast Cancer to Evaluate Survival and Immunotherapy

As one of the most prevalent malignancies among women, breast cancer (BC) is tightly linked to metabolic dysfunction. However, the correlation between mitochondrial metabolism-related genes (MMRGs) and BC remains unclear. The training and validation datasets for BC were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases, respectively. MMRG-related data were obtained from the Molecular Signatures Database. A risk score prognostic model incorporating MMRGs was established based on univariate, LASSO, and multivariate Cox regression analyses. Independent factors affecting BC prognosis were identified through regression analysis and presented in a nomogram. Single-sample gene set enrichment analysis was employed to assess the immune levels of high-risk (HR) and low-risk (LR) groups. The sensitivity of BC patients in the two groups to common anti-tumor drugs was evaluated by utilizing the Genomics of Drug Sensitivity in Cancer database. 12 MMRGs significantly associated with survival were selected from 1234 MMRGs. A 12-gene risk score prognostic model was built. In the multivariate regression analysis incorporating classical clinical factors, the MMRG-related risk score remained an independent prognostic factor. As revealed by tumor immune microenvironment analysis, the LR group with higher survival rates had elevated immune levels. The drug sensitivity results unmasked that the LR group demonstrated higher sensitivity to Irinotecan, Nilotinib, and Oxaliplatin, while the HR group demonstrated higher sensitivity to Lapatinib. The development of MMRG characteristics provides a comprehensive understanding of mitochondrial metabolism in BC, aiding in the prediction of prognosis and tumor microenvironment, and offering promising therapeutic choices for BC patients with different MMRG risk scores.

Clinical and genetic characteristics of CEL-MODY (MODY8): a literature review and screening in Chinese individuals diagnosed with early-onset type 2 diabetes

OBJECTIVE

CEL-related maturity-onset diabetes of the young (CEL-MODY, MODY8) is a special type of monogenetic diabetes caused by mutations in the carboxyl-ester lipase (CEL) gene. This study aimed to summarize the genetic and clinical characteristics of CEL-MODY patients and to determine the prevalence of the disease among Chinese patients with early-onset type 2 diabetes (EOD).

METHODS

We systematically reviewed the literature associated with CEL-MODY in PubMed, Embase, Web of Science, China National Knowledge Infrastructure and Wanfang Data to analyze the features of patients with CEL-MODY. We screened and evaluated rare variants of the CEL gene in a cohort of 679 Chinese patients with EOD to estimate the prevalence of CEL-MODY in China.

RESULTS

In total, 21 individuals reported in previous studies were diagnosed with CEL-MODY based on the combination of diabetes and pancreatic exocrine dysfunction as well as frameshift mutations in exon 11 of the CEL gene. CEL-MODY patients were nonobese and presented with exocrine pancreatic affection (e.g., chronic pancreatitis, low fecal elastase levels, pancreas atrophy and lipomatosis) followed by insulin-dependent diabetes. No carriers of CEL missense mutations were reported with exocrine pancreatic dysfunction. Sequencing of CEL in Chinese EOD patients led to the identification of the variant p.Val736Cysfs*22 in two patients. However, these patients could not be diagnosed with CEL-MODY because there were no signs that the exocrine pancreas was afflicted.

CONCLUSION

CEL-MODY is a very rare disease caused by frameshift mutations affecting the proximal VNTR segments of the CEL gene. Signs of exocrine pancreatic dysfunction provide diagnostic clues for CEL-MODY, and genetic testing is vital for proper diagnosis. Further research in larger cohorts is needed to investigate the characteristics and prevalence of CEL-MODY in the Chinese population.

Enzymatically Activatable Polymers for Disease Diagnosis and Treatment

The irregular expression or activity of enzymes in the human body leads to various pathological disorders and can therefore be used as an intrinsic trigger for more precise identification of disease foci and controlled release of diagnostics and therapeutics, leading to improved diagnostic accuracy, sensitivity, and therapeutic efficacy while reducing systemic toxicity. Advanced synthesis strategies enable the preparation of polymers with enzymatically activatable skeletons or side chains, while understanding enzymatically responsive mechanisms promotes rational incorporation of activatable units and predictions of the release profile of diagnostics and therapeutics, ultimately leading to promising applications in disease diagnosis and treatment with superior biocompatibility and efficiency. By overcoming the challenges, new opportunities will emerge to inspire researchers to develop more efficient, safer, and clinically reliable enzymatically activatable polymeric carriers as well as prodrugs.

Intrauterine growth restriction in piglets modulates postnatal immune function and hepatic transcriptional responses independently of energy intake

Introduction: Insufficient prenatal nutrition can affect fetal development and lead to intrauterine growth restriction (IUGR). The aim of this study was to investigate hepatic transcriptional responses and innate immune function in piglets suffering from IUGR compared to normal-sized piglets at 3 days of age and explore whether the provision of an energy-rich supplement at birth could modulate these parameters. Methods: A total of 68 piglets were included in the study. Peripheral blood mononuclear cells were harvested for LPS stimulation, and organs were harvested post-mortem to quantify relative weights. Liver tissue was utilized for RNA sequencing coupled with gene-set enrichment analysis. Results: IUGR resulted in increased expression of genes such as PDK4 and substantial alterations in transcriptional pathways related to metabolic activity (e.g., citric acid and Krebs cycles), but these changes were equivalent in piglets given an energy-rich supplement or not. Transcriptomic analysis and serum biochemistry suggested altered glucose metabolism and a shift toward oxidation of fatty acids. IUGR piglets also exhibited suppression of genes related to innate immune function (e.g., CXCL12) and pathways related to cell proliferation (e.g., WNT and PDGF signaling). Moreover, they produced less IL-1β in response to LPS stimulation and had lower levels of blood eosinophils than normal-sized piglets. Discussion: Taken together, our results indicate that IUGR results in early-life alterations in metabolism and immunity that may not be easily restored by the provision of exogenous energy supplementation.

Exploring the key genetic association between chronic pancreatitis and pancreatic ductal adenocarcinoma through integrated bioinformatics

Background: Pancreatic ductal adenocarcinoma (PDAC) develops rapidly and has a poor prognosis. It has been demonstrated that pancreatic ductal adenocarcinoma and chronic pancreatitis (CP) have a close connection. However, the underlying mechanisms for chronic pancreatitis transforming into pancreatic ductal adenocarcinoma are still unclear. The purpose of this study was to identify real hub genes in the development of chronic pancreatitis and pancreatic ductal adenocarcinoma. Methods: RNA-seq data of chronic pancreatitis and pancreatic ductal adenocarcinoma were downloaded from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was performed to construct a gene co-expression network between chronic pancreatitis and pancreatic ductal adenocarcinoma. GEO2R and a Venn diagram were used to identify differentially expressed genes. Then visualized networks were constructed with ClueGO, and modules of PPI network were calculated by MCODE plugin. Further validation of the results was carried out in two additional cohorts. Analyses of CEL-coexpressed genes and regulators including miRNAs and transcription factors were performed by using the corresponding online web tool. Finally, the influence of CEL in the tumor immune microenvironment (TIME) was assessed by immune contextual analysis. Results: With the help of WGCNA and GEO2R, four co-expression modules and six hub genes were identified, respectively. ClueGO enrichment analysis and MCODE cluster analysis revealed that the dysfunctional transport of nutrients and trace elements might contribute to chronic pancreatitis and pancreatic ductal adenocarcinoma development. The real hub gene CEL was identified with a markedly low expression in pancreatic ductal adenocarcinoma in external validation sets. According to the miRNA-gene network construction, hsa-miR-198 may be the key miRNA. A strong correlation exists between CEL and TIME after an evaluation of the influence of CEL in TIME. Conclusion: Our study revealed the dysfunctional transport of nutrients and trace elements may be common pathogenesis of pancreatic ductal adenocarcinoma and chronic pancreatitis. Examination on these common pathways and real hub genes may shed light on the underlying mechanism.

LncRNA Regulation Mechanism in Hepatic Alveolar Echinococcosis with Nanosecond Pulse

BACKGROUND

The mortality of patients infected with hepatic alveolar echinococcosis (HAE) was higher. The aim of this study was to investigate the therapeutic effect of nanosecond pulsed electric fields (nsPEFs) on HAE in rats and explore the related molecular mechanisms.

METHODS

Establishment of HAE rat model and the lesions were treated with nsPEFs. The RNA of lesions in the high voltage nsPEFs treatment group and model group were extracted, and lncRNA and mRNA sequence analyses was performed. After obtaining the differentially expressed lncRNAs and mRNAs between the two groups, enrichment analysis was performed for mRNAs. The target genes of lncRNAs were predicted through co-location and co-expression. The expression of important lncRNAs and target genes in lesions was detected by qPCR.

RESULTS

The HAE rat model was successfully established. After nsPEFs treatment, the size of lesions was improved significantly. Then, we identified 270 differentially expressed lncRNAs and 1659 differentially expressed mRNAs between the high voltage nsPEFs treatment group and model group. Enrichment analysis showed that the differentially expressed mRNAs were mainly enriched in metabolism and inflammation. Five important lncRNAs regulatory networks were identified, then Cpa1, Cpb1, Cel, Cela2a, and Cela3b were identified as key target genes. Importantly, the expression of 5 lncRNAs and 5 target genes was verified in the lesions.

CONCLUSIONS

Preliminary results had shown that HAE treatment with nsPEFs can inhibit the growth of lesions. NsPEFs treatment altered gene expression in the lesions, and some genes were regulated by lncRNAs. The therapeutic mechanism may involve metabolism and inflammation.

Cell differentiation modifies the p53 transcriptional program through a combination of gene silencing and constitutive transactivation

The p53 transcription factor is a master regulator of cellular responses to stress that is commonly inactivated in diverse cancer types. Despite decades of research, the mechanisms by which p53 impedes tumorigenesis across vastly different cellular contexts requires further investigation. The bulk of research has been completed using in vitro studies of cancer cell lines or in vivo studies in mouse models, but much less is known about p53 action in diverse non-transformed human tissues. Here, we investigated how different cellular states modify the p53 transcriptional program in human cells through a combination of computational analyses of publicly available large-scale datasets and in vitro studies using an isogenic system consisting of induced pluripotent stem cells (iPSCs) and two derived lineages. Analysis of publicly available mRNA expression and genetic dependency data demonstrated wide variation in terms of expression and function of a core p53 transcriptional program across various tissues and lineages. To monitor the impact of cell differentiation on the p53 transcriptome within an isogenic cell culture system, we activated p53 by pharmacological inhibition of its negative regulator MDM2. Using cell phenotyping assays and genome wide transcriptome analyses, we demonstrated that cell differentiation confines and modifies the p53 transcriptional network in a lineage-specific fashion. Although hundreds of p53 target genes are transactivated in iPSCs, only a small fraction is transactivated in each of the differentiated lineages. Mechanistic studies using small molecule inhibitors and genetic knockdowns revealed the presence of two major regulatory mechanisms contributing to this massive heterogeneity across cellular states: gene silencing by epigenetic regulatory complexes and constitutive transactivation by lineage-specific transcription factors. Altogether, these results illuminate the impact of cell differentiation on the p53 program, thus advancing our understanding of how this tumor suppressor functions in different contexts.

Monogenic diabetes

Monogenic diabetes includes several clinical conditions generally characterized by early-onset diabetes, such as neonatal diabetes, maturity-onset diabetes of the young (MODY) and various diabetes-associated syndromes. However, patients with apparent type 2 diabetes mellitus may actually have monogenic diabetes. Indeed, the same monogenic diabetes gene can contribute to different forms of diabetes with early or late onset, depending on the functional impact of the variant, and the same pathogenic variant can produce variable diabetes phenotypes, even in the same family. Monogenic diabetes is mostly caused by impaired function or development of pancreatic islets, with defective insulin secretion in the absence of obesity. The most prevalent form of monogenic diabetes is MODY, which may account for 0.5-5% of patients diagnosed with non-autoimmune diabetes but is probably underdiagnosed owing to insufficient genetic testing. Most patients with neonatal diabetes or MODY have autosomal dominant diabetes. More than 40 subtypes of monogenic diabetes have been identified to date, the most prevalent being deficiencies of GCK and HNF1A. Precision medicine approaches (including specific treatments for hyperglycaemia, monitoring associated extra-pancreatic phenotypes and/or following up clinical trajectories, especially during pregnancy) are available for some forms of monogenic diabetes (including GCK- and HNF1A-diabetes) and increase patients' quality of life. Next-generation sequencing has made genetic diagnosis affordable, enabling effective genomic medicine in monogenic diabetes.

Identification and characterization of novel carboxyl ester lipase gene variants in patients with different subtypes of diabetes

INTRODUCTION

Mutations of CEL gene were first reported to cause a new type of maturity-onset diabetes of the young (MODY) denoted as MODY8 and then were also found in patients with type 1 (T1D) and type 2 diabetes (T2D). However, its genotype-phenotype relationship has not been fully determined and how carboxyl ester lipase (CEL) variants result in diabetes remains unclear. The aim of our study was to identify pathogenic variants of CEL in patients with diabetes and confirm their pathogenicity.

RESEARCH DESIGN AND METHODS

All five patients enrolled in our study were admitted to Shandong Provincial Hospital and diagnosed with diabetes in the past year. Whole-exome sequencing was performed to identify pathogenic variants in three patients with MODY-like diabetes, one newborn baby with T1D and one patient with atypical T2D, as well as their immediate family members. Then the consequences of the identified variants were predicted by bioinformatic analysis. Furthermore, pathogenic effects of two novel CEL variants were evaluated in HEK293 cells transfected with wild-type and mutant plasmids. Finally, we summarized all CEL gene variants recorded in Human Gene Mutation Database and analyzed the mutation distribution of CEL.

RESULTS

Five novel heterozygous variants were identified in CEL gene and they were predicted to be pathogenic by bioinformatic analysis. Moreover, in vitro studies indicated that the expression of CEL^R540C was remarkably increased, while p.G729_T739del variant did not significantly affect the expression of CEL. Both novel variants obviously abrogated the secretion of CEL. Furthermore, we summarized all reported CEL variants and found that 74.3% of missense mutations were located in exons 1, 3, 4, 10 and 11 and most missense variants clustered near catalytic triad, Arg-83 and Arg-443.

CONCLUSION

Our study identified five novel CEL variants in patients with different subtypes of diabetes, expanding the gene mutation spectrum of CEL and confirmed the pathogenicity of several novel variants.

The genetic risk factor CEL-HYB1 causes proteotoxicity and chronic pancreatitis in mice

BACKGROUND & AIMS

The CEL gene encodes the digestive enzyme carboxyl ester lipase. CEL-HYB1, a hybrid allele of CEL and its adjacent pseudogene CELP, is a genetic variant suggested to increase the risk of chronic pancreatitis (CP). Our aim was to develop a mouse model for CEL-HYB1 that enables studies of pancreatic disease mechanisms.

METHODS

We established a knock-in mouse strain where the variable number of tandem repeat (VNTR) region of the endogenous mouse Cel gene was substituted with the mutated VNTR of the human CEL-HYB1 allele. Heterozygous and homozygous Cel-HYB1 mice and littermate wildtype controls were characterized with respect to pancreatic pathology and function.

RESULTS

We successfully constructed a mouse model with pancreatic expression of a humanized CEL-HYB1 protein. The Cel-HYB1 mice spontaneously developed features of CP including inflammation, acinar atrophy and fatty replacement, and the phenotype became more pronounced as the animals aged. Moreover, Cel-HYB1 mice were normoglycemic at age 6 months, whereas at 12 months they exhibited impaired glucose tolerance. Immunostaining of pancreatic tissue indicated the formation of CEL protein aggregates, and electron microscopy showed dilated endoplasmic reticulum. Upregulation of the stress marker BiP/GRP78 was seen in pancreatic parenchyma obtained both from Cel-HYB1 animals and from a human CEL-HYB1 carrier.

CONCLUSIONS

We have developed a new mouse model for CP that confirms the pathogenicity of the human CEL-HYB1 variant. Our findings place CEL-HYB1 in the group of genes that increase CP risk through protein misfolding-dependent pathways.

Disrupted microbiota-barrier-immune interaction in phthalates-mediated barrier defect in the duodenum

As one of the most used phthalates, Di (2-ethylhexyl) phthalate (DEHP) is a widespread environmental contaminant. Extremely persistent plastic can enter the food chain of animals through the aquatic environment, affect metabolic pathways and cause damage to the digestive system. But the molecular mechanism of its toxic effects on the duodenum in birds has not been elucidated. To investigate the toxicity of phthalates in the duodenum, quails were gavaged with 250, 500, and 750 mg/kg doses of DEHP for 45 days, and water and oil control groups were retained. This study revealed that subchronic exposure to DEHP could lead to duodenal barrier defect in quail. The damage to duodenum was reflected in a reduction in V/C and tight junction proteins. Moreover, DEHP also led to a breakdown of antimicrobial defenses through the flora derangement, which acted as a biological barrier. The massive presence of Lipopolysaccharide (LPS) led to the activation of TLR4 receptors. In addition, DEHP activated oxidative stress, which synergized the inflammatory response induced by the TLR4-NFκB pathway, and further promoted duodenum damage. This study provides a base for the further effect of phthalates on the microbiota-barrier-immune interaction.

Endoplasmic stress-inducing variants in carboxyl ester lipase and pancreatic cancer risk

BACKGROUND

Endoplasmic reticulum (ER) stress-inducing variants in several pancreatic secretory enzymes have been associated with pancreatic disease. Multiple variants in CEL, encoding carboxyl ester lipase, are known to cause maturity-onset diabetes of the young (MODY8) but have not been implicated in pancreatic cancer risk.

METHODS

The prevalence of ER stress-inducing variants in the CEL gene was compared among pancreatic cancer cases vs. controls. Variants were identified by next-generation sequencing and confirmed by Sanger sequencing. Variants of uncertain significance (VUS) were assessed for their effect on the secretion of CEL protein and variants with reduced protein secretion were evaluated to determine if they induced endoplasmic reticulum stress.

RESULTS

ER stress-inducing CEL variants were found in 34 of 986 cases with sporadic pancreatic ductal adenocarcinoma, and 21 of 1045 controls (P = 0.055). Most of the variants were either the CEL-HYB1 variant, the I488T variant, or the combined CEL-HYB1/I488T variant; one case had a MODY8 variant.

CONCLUSION

This case/control analysis finds ER stress-inducing CEL variants are not associated with an increased likelihood of having pancreatic cancer.

Maturity-Onset Diabetes of the Young: Mutations, Physiological Consequences, and Treatment Options

Maturity-Onset Diabetes of the Young (MODY) is a rare form of diabetes which affects between 1% and 5% of diagnosed diabetes cases. Clinical characterizations of MODY include onset of diabetes at an early age (before the age of 30), autosomal dominant inheritance pattern, impaired glucose-induced secretion of insulin, and hyperglycemia. Presently, 14 MODY subtypes have been identified. Within these subtypes are several mutations which contribute to the different MODY phenotypes. Despite the identification of these 14 subtypes, MODY is often misdiagnosed as type 1 or type 2 diabetes mellitus due to an overlap in clinical features, high cost and limited availability of genetic testing, and unfamiliarity with MODY outside of the medical profession. The primary aim of this review is to investigate the genetic characterization of the MODY subtypes. Additionally, this review will elucidate the link between the genetics, function, and clinical manifestations of MODY in each of the 14 subtypes. In providing this knowledge, we hope to assist in the accurate diagnosis of MODY patients and, subsequently, in ensuring they receive appropriate treatment.

Machine learning based identification of hub genes in renal clear cell carcinoma using multi-omics data

Renal cell carcinoma is one of the most universal urinary system cancers in the world. The most common renal cell carcinoma subtype is renal clear cell carcinoma. It is usually associated with high rates of metastasis and mortality. Therefore, finding effective therapeutic targets and prognostic molecular markers is of great significance to improve the early diagnosis rate and prognostic accuracy of renal clear cell carcinoma. In this work, we successfully identified six hub genes that are closely related to the occurrence, development and prognosis of renal clear cell carcinoma and proposed three new potential prognostic markers, namely ATP4B, AC144831.1 and Tfcp2l1 through differentially expressed genes (DEGs) analysis, GO functional enrichment and KEGG pathway analysis, WGCNA analysis, and survival analysis. In addition, we established machine learning models to predict the occurrence of tumors through the gene expression data of patients. It is expected that the results of this study can provide reference value for the treatment of renal clear cell carcinoma.

3D chromatin maps of the human pancreas reveal lineage-specific regulatory architecture of T2D risk

Three-dimensional (3D) chromatin organization maps help dissect cell-type-specific gene regulatory programs. Furthermore, 3D chromatin maps contribute to elucidating the pathogenesis of complex genetic diseases by connecting distal regulatory regions and genetic risk variants to their respective target genes. To understand the cell-type-specific regulatory architecture of diabetes risk, we generated transcriptomic and 3D epigenomic profiles of human pancreatic acinar, alpha, and beta cells using single-cell RNA-seq, single-cell ATAC-seq, and high-resolution Hi-C of sorted cells. Comparisons of these profiles revealed differential A/B (open/closed) chromatin compartmentalization, chromatin looping, and transcriptional factor-mediated control of cell-type-specific gene regulatory programs. We identified a total of 4,750 putative causal-variant-to-target-gene pairs at 194 type 2 diabetes GWAS signals using pancreatic 3D chromatin maps. We found that the connections between candidate causal variants and their putative target effector genes are cell-type stratified and emphasize previously underappreciated roles for alpha and acinar cells in diabetes pathogenesis.

Misaligned feeding schedule elicits divergent circadian reorganizations in endo- and exocrine pancreas clocks

Misaligned feeding may lead to pancreatic insufficiency, however, whether and how it affects circadian clock in the exocrine pancreas is not known. We exposed rats to a reversed restricted feeding regimen (rRF) for 10 or 20 days and analyzed locomotor activity, daily profiles of hormone levels (insulin, glucagon, and corticosterone) in plasma, and clock gene expression in the liver and endocrine and exocrine pancreas. In addition, we monitored responses of the exocrine pancreatic clock in organotypic explants of mPer2Luc mice in real time to acetylcholine, insulin, and glucocorticoids. rRF phase-reversed the clock in the endocrine pancreas, similar to the clock in the liver, but completely abolished clock gene rhythmicity and significantly downregulated the expression of Cpb1 and Cel in the exocrine pancreas. rRF desynchronized the rhythms of plasma insulin and corticosterone. Daily profiles of their receptor expression differed in the two parts of the pancreas and responded differently to rRF. Additionally, the pancreatic exocrine clock responded differently to treatments with insulin and the glucocorticoid analog dexamethasone in vitro. Mathematical simulation confirmed that the long-term misalignment between these two hormonal signals, as occurred under rRF, may lead to dampening of the exocrine pancreatic clock. In summary, our data suggest that misaligned meals impair the clock in the exocrine part of the pancreas by uncoupling insulin and corticosterone rhythms. These findings suggest a new mechanism by which adverse dietary habits, often associated with shift work in humans, may impair the clock in the exocrine pancreas and potentially contribute to exocrine pancreatic insufficiency.

The CEL-HYB1 Hybrid Allele Promotes Digestive Enzyme Misfolding and Pancreatitis in Mice

BACKGROUND & AIMS

A hybrid allele that originated from homologous recombination between CEL and its pseudogene (CELP), CEL-HYB1 increases the risk of chronic pancreatitis (CP). Although suggested to cause digestive enzyme misfolding, definitive in vivo evidence for this postulate has been lacking.

METHODS

CRISPR-Cas9 was used to generate humanized mice harboring the CEL-HYB1 allele on a C57BL/6J background. Humanized CEL mice and C57BL/6J mice were used as controls. Pancreata were collected and analyzed by histology, immunohistochemistry, immunoblotting, and transcriptomics. Isolated pancreatic acini were cultured in vitro to measure the secretion and aggregation of CEL-HYB1 protein. Mice were given caerulein injections to induce acute pancreatitis (AP) and CP.

RESULTS

Pancreata from mice expressing CEL-HYB1 developed pathological features characteristic of focal pancreatitis that included acinar atrophy and vacuolization, inflammatory infiltrates, and fibrosis in a time-dependent manner. CEL-HYB1 expression in pancreatic acini led to decreased secretion and increased intracellular aggregation and triggered endoplasmic reticulum stress compared with CEL. The autophagy levels of pancreata from mice expressing CEL-HYB1 changed at different developmental stages; some aged CEL-HYB1 mice exhibited an accumulation of large autophagic vesicles and impaired autophagy in acinar cells. Administration of caerulein increased the severity of AP/CP in mice expressing CEL-HYB1 compared with control mice, accompanied by higher levels of endoplasmic reticulum stress.

CONCLUSIONS

Expression of a humanized form of CEL-HYB1 in mice promotes endoplasmic reticulum stress and pancreatitis through a misfolding-dependent pathway. Impaired autophagy appears to be involved in the pancreatic injury in aged CEL-HYB1 mice. These mice have the potential to be used as a model to identify therapeutic targets for CP.

Two New Mutations in the CEL Gene Causing Diabetes and Hereditary Pancreatitis: How to Correctly Identify MODY8 Cases

CONTEXT

Maturity onset diabetes of the young, type 8 (MODY8) is associated with mutations in the CEL gene, which encodes the digestive enzyme carboxyl ester lipase. Several diabetes cases and families have in recent years been attributed to mutations in CEL without any functional or clinical evidence provided.

OBJECTIVE

To facilitate correct MODY8 diagnostics, we screened 2 cohorts of diabetes patients and delineated the phenotype.

METHODS

Young, lean Swedish and Finnish patients with a diagnosis of type 2 diabetes (352 cases, 406 controls) were screened for mutations in the CEL gene. We also screened 58 Czech MODY cases who had tested negative for common MODY genes. For CEL mutation-positive subjects, family history was recorded, and clinical investigations and pancreatic imaging performed.

RESULTS

Two cases (1 Swedish and 1 Czech) with germline mutation in CEL were identified. Clinical and radiological investigations of these 2 probands and their families revealed dominantly inherited insulin-dependent diabetes, pancreatic exocrine dysfunction, and atrophic pancreas with lipomatosis and cysts. Notably, hereditary pancreatitis was the predominant phenotype in 1 pedigree. Both families carried single-base pair deletions in the proximal part of the CEL variable number of tandem repeat (VNTR) region in exon 11. The mutations are predicted to lead to aberrant protein tails that make the CEL protein susceptible to aggregation.

CONCLUSION

The diagnosis of MODY8 requires a pancreatic exocrine phenotype and a deletion in the CEL VNTR in addition to dominantly inherited diabetes. CEL screening may be warranted also in families with hereditary pancreatitis of unknown genetic etiology.

Prenatal inflammation causes obesity and abnormal lipid metabolism via impaired energy expenditure in male offspring

INTRODUCTION

Obesity has becoming a global health issue. Fetus exposed to adversity in the uterine are susceptible to unhealth stimulus in adulthood. Prenatal inflammation is related to poor neonatal outcomes like neurodevelopmental impairments and respiratory complications. Recent studies suggested prenatal lipopolysaccharide (LPS) exposure could result in metabolic disorders. Thus, we hypothesized that offspring exposed to prenatal inflammation could develop into metabolic disorder.

METHODS

The pregnant C57BL/6J mice were intraperitoneally injected with 50 μg/kg LPS or saline only once at GD15. The male offspring were weighted weekly until sacrificed. Indirect calorimetry and body composition were both performed at 9 and 18 weeks old. At 20 weeks old, mice were fasted overnight before collecting blood samples and liver for metabolomics analysis and RNA sequencing, respectively. Differentially expressed genes were further verified by RT-qPCR and western blotting.

RESULTS

Prenatal inflammation resulted in obesity with increased fat percentage and decreased energy expenditure in middle-age male offspring. Abnormal lipid accumulation, changes of gene expression profile and upregulation of multi-component mechanistic target of rapamycin complex 1 (mTOR)/Peroxisome proliferator-activated receptor-γ pathway was observed in liver, accompanied with decreased bile acids level, unsaturated fatty acids androgens and prostaglandins in serum. Indirect calorimetry showed increased respiratory exchange rate and deceased spontaneous activity at 9 weeks in LPS group. Impaired energy expenditure was also observed at 18 weeks in LPS group.

CONCLUSION

Prenatal LPS exposure led to obesity and abnormal lipid metabolism through impaired energy expenditure.

Development of the human pancreas and its exocrine function

The pancreas has both endocrine and exocrine function and plays an important role in digestion and glucose control. Understanding the development of the pancreas, grossly and microscopically, and the genetic factors regulating it provides further insight into clinical problems that arise when these processes fail. Animal models of development are known to have inherent issues when understanding human development. Therefore, in this review, we focus on human studies that have reported gross and microscopic development including acinar-, ductal-, and endocrine cells and the neural network. We review the genes and transcription factors involved in organ formation using data from animal models to bridge current understanding where necessary. We describe the development of exocrine function in the fetus and postnatally. A deeper review of the genes involved in pancreatic formation allows us to describe the development of the different groups (proteases, lipids, and amylase) of enzymes during fetal life and postnatally and describe the genetic defects. We discuss the constellation of gross anatomical, as well as microscopic defects that with genetic mutations lead to pancreatic insufficiency and disease states.

Transcriptome analysis provides insights into the anti-diabetic mechanism of theaflavins in high-fat diet and streptozotocin-induced mice

Black tea exhibits potential to improve hyperglycemia and insulin resistance, and theaflavins (TFs) are one of its characteristic components. The aim of this study was to explore the anti-diabetic mechanism...

Exocrine-Endocrine Crosstalk: The Influence of Pancreatic Cellular Communications on Organ Growth, Function and Disease

Diabetes mellitus, a disease that affects nearly 536.6 million people worldwide, is characterized by the death or dysfunction of insulin-producing beta cells of the pancreas. The beta cells are found within the islets of Langerhans, which are composed of multiple hormone-producing endocrine cells including the alpha (glucagon), delta (somatostatin), PP (pancreatic polypeptide), and epsilon (ghrelin) cells. There is direct evidence that physical and paracrine interactions between the cells in the islet facilitate and support beta cell function. However, communication between endocrine and exocrine cells in the pancreas may also directly impact beta cell growth and function. Herein we review literature that contributes to the view that "crosstalk" between neighboring cells within the pancreas influences beta cell growth and function and the maintenance of beta cell health.

Abnormal exocrine-endocrine cell cross-talk promotes β-cell dysfunction and loss in MODY8

MODY8 (maturity-onset diabetes of the young, type 8) is a dominantly inherited monogenic form of diabetes associated with mutations in the carboxyl ester lipase (CEL) gene expressed by pancreatic acinar cells. MODY8 patients develop childhood-onset exocrine pancreas dysfunction followed by diabetes during adulthood. However, it is unclear how CEL mutations cause diabetes. In the present study, we report the transfer of CEL proteins from acinar cells to β-cells as a form of cross-talk between exocrine and endocrine cells. Human β-cells show a relatively higher propensity for internalizing the mutant versus the wild-type CEL protein. After internalization, the mutant protein forms stable intracellular aggregates leading to β-cell secretory dysfunction. Analysis of pancreas sections from a MODY8 patient reveals the presence of CEL protein in the few extant β-cells. The present study provides compelling evidence for the mechanism by which a mutant gene expressed specifically in acinar cells promotes dysfunction and loss of β-cells to cause diabetes.

KRAS mutation analysis by droplet digital PCR of duodenal juice from patients with MODY8 and other pancreatic diseases

BACKGROUND

Maturity-onset diabetes of the young type 8 (MODY8 or CEL-MODY) is an inherited pancreatic disease characterized by chronic inflammation of the pancreas and diabetes. It is not known whether MODY8 patients have increased risk for developing pancreatic cancer. We investigated KRAS mutation load in duodenal juice from MODY8 patients, comparing with other groups of pancreatic disease.

METHODS

Droplet digital PCR (ddPCR) was used to detect KRAS codon 12/13/61 mutations in duodenal juice sampled from 11 MODY8 patients, nine healthy subjects and 100 patients clinically investigated due to suspected pancreatic disease.

RESULTS

KRAS mutations were detected in 4/11 patients with MODY8 (36%), 1/9 healthy subjects (11%), 15/44 patients with chronic pancreatitis (CP, 34%), 3/5 patients with pancreatic ductal adenocarcinoma (PDAC, 60%), 3/20 patients with acute pancreatitis (15%), 0/13 patients with other pancreatic disorders and 2/18 patients with nonpancreatic gastrointestinal disease (11%). Of the 28 positive juice samples, 25 (89%) had low-abundance mutations in codons 12/13, with a variant allele frequency (VAF) less than 1%. KRAS-positive patients with MODY8 or CP had significantly lower VAFs than patients with PDAC (Mann-Whitney U test; p = 0.041). Although the overall mutation detection rate was higher for subjects ≥50 years old (26%) than for younger subjects (15%), the difference was not statistically significant.

CONCLUSIONS

KRAS mutations were detectable in duodenal juice from MODY8 patients, but with low abundance and at the same frequency as in CP patients. The discriminative value of the analysis with regard to other pancreatic disease was limited.

Homozygosity of short VNTR lengths in the CEL gene may confer susceptibility to idiopathic chronic pancreatitis

OBJECTIVE

The carboxyl-ester lipase (CEL) gene contains a variable number of tandem repeats (VNTR) region. It remains unclear whether the number of repeats in the CEL VNTR is related to the risk of pancreatic diseases. The aim of this study was to investigate whether CEL VNTR length is associated with idiopathic chronic pancreatitis (ICP), alcoholic chronic pancreatitis (ACP), or pancreatic cancer in a cohort of Chinese patients.

METHODS

CEL VNTRs were genotyped in patients diagnosed with ICP (n = 771), ACP (n = 222), or pancreatic cancer (n = 263), and in healthy controls (n = 927). CEL VNTR lengths were determined using a screening method combining PCR and DNA fragment analysis.

RESULTS

Overall, the CEL VNTR lengths ranged from 5 to 22 repeats, with the 16-repeat allele ('normal' size, N) accounting for 73.82% of all observed alleles. The VNTR allele frequencies and genotype distributions were not significantly different between healthy controls and patients with ACP or pancreatic cancer. For the ICP group, allele frequencies did not differ significantly from the controls, while the frequency of the SS genotype (homozygosity for 5-15 repeats) was significantly higher in the patients (4.67%) than in the controls (1.94%) (p = 0.0014; OR = 2.47; 95% CI = 1.39-4.39).

CONCLUSIONS

There were no associations between the CEL VNTR length and ACP or pancreatic cancer. However, homozygosity for short VNTR lengths may confer susceptibility to ICP.

Interpreting type 1 diabetes risk with genetics and single-cell epigenomics

Genetic risk variants that have been identified in genome-wide association studies of complex diseases are primarily non-coding1. Translating these risk variants into mechanistic insights requires detailed maps of gene regulation in disease-relevant cell types2. Here we combined two approaches: a genome-wide association study of type 1 diabetes (T1D) using 520,580 samples, and the identification of candidate cis-regulatory elements (cCREs) in pancreas and peripheral blood mononuclear cells using single-nucleus assay for transposase-accessible chromatin with sequencing (snATAC-seq) of 131,554 nuclei. Risk variants for T1D were enriched in cCREs that were active in T cells and other cell types, including acinar and ductal cells of the exocrine pancreas. Risk variants at multiple T1D signals overlapped with exocrine-specific cCREs that were linked to genes with exocrine-specific expression. At the CFTR locus, the T1D risk variant rs7795896 mapped to a ductal-specific cCRE that regulated CFTR; the risk allele reduced transcription factor binding, enhancer activity and CFTR expression in ductal cells. These findings support a role for the exocrine pancreas in the pathogenesis of T1D and highlight the power of large-scale genome-wide association studies and single-cell epigenomics for understanding the cellular origins of complex disease.

Genetic Risk Factors in Early-Onset Nonalcoholic Chronic Pancreatitis: An Update

Chronic pancreatitis (CP) is a progressive, irreversible inflammatory disorder of the pancreas, which results from interrelations between different genetic and environmental factors. Genetic variants are the primary cause of the disease in early-onset nonalcoholic CP patients. Novel CP-associated genes are continuously emerging from genetic studies on CP cohorts, providing important clues for distinct mechanisms involved in CP development. On the basis of functional studies, the genetic alterations have been sub-grouped into CP-driving pathological pathways. This review focuses on the concept of CP as a complex disease driven by multiple genetic factors. We will discuss only well-defined genetic risk factors and distinct functional pathways involved in CP development, especially in the context of the early-onset nonalcoholic CP group. The diagnostic implications of the genetic testing will be addressed as well.

Molecular phyloecology suggests a trophic shift concurrent with the evolution of the first birds

Birds are characterized by evolutionary specializations of both locomotion (e.g., flapping flight) and digestive system (toothless, crop, and gizzard), while the potential selection pressures responsible for these evolutionary specializations remain unclear. Here we used a recently developed molecular phyloecological method to reconstruct the diets of the ancestral archosaur and of the common ancestor of living birds (CALB). Our results suggest a trophic shift from carnivory to herbivory (fruit, seed, and/or nut eater) at the archosaur-to-bird transition. The evolutionary shift of the CALB to herbivory may have essentially made them become a low-level consumer and, consequently, subject to relatively high predation risk from potential predators such as gliding non-avian maniraptorans, from which birds descended. Under the relatively high predation pressure, ancestral birds with gliding capability may have then evolved not only flapping flight as a possible anti-predator strategy against gliding predatory non-avian maniraptorans but also the specialized digestive system as an evolutionary tradeoff of maximizing foraging efficiency and minimizing predation risk. Our results suggest that the powered flight and specialized digestive system of birds may have evolved as a result of their tropic shift-associated predation pressure.

Generation of β Cells from iPSC of a MODY8 Patient with a Novel Mutation in the Carboxyl Ester Lipase (CEL) Gene

CONTEXT

Maturity-onset diabetes of the young (MODY) 8 is a rare form of monogenic diabetes characterized by a mutation in CEL (carboxyl ester lipase) gene, which leads to exocrine pancreas dysfunction, followed by β cell failure. Induced pluripotent stem cells can differentiate into functional β cells. Thus, β cells from MODY8 patients can be generated in vitro and used for disease modelling and cell replacement therapy.

METHODS

A genetic study was performed in a patient suspected of monogenic diabetes.

RESULTS

A novel heterozygous pathogenic variant in CEL (c.1818delC) was identified in the proband, allowing diagnosis of MODY8. Three MODY8-iPSC (induced pluripotent stem cell) clones were reprogrammed from skin fibroblasts of the patient, and their pluripotency and genomic stability confirmed. All 3 MODY8-iPSC differentiated into β cells following developmental stages. MODY8-iPSC-derived β cells were able to secrete insulin upon glucose dynamic perifusion. The CEL gene was not expressed in iPSCs nor during any steps of endocrine differentiation.

CONCLUSION

iPSC lines from a MODY8 patient with a novel pathogenic variant in the CEL gene were generated; they are capable of differentiation into endocrine cells, and β cell function is preserved in mutated cells. These results set the basis for in vitro modelling of the disease and potentially for autologous β cell replacement.

The position of single-base deletions in the VNTR sequence of the carboxyl ester lipase (CEL) gene determines proteotoxicity

Variable number of tandem repeat (VNTR) sequences in the genome can have functional consequences that contribute to human disease. This is the case for the CEL gene, which is specifically expressed in pancreatic acinar cells and encodes the digestive enzyme carboxyl ester lipase. Rare single-base deletions (DELs) within the first (DEL1) or fourth (DEL4) VNTR segment of CEL cause maturity-onset diabetes of the young, type 8 (MODY8), an inherited disorder characterized by exocrine pancreatic dysfunction and diabetes. Studies on the DEL1 variant have suggested that MODY8 is initiated by CEL protein misfolding and aggregation. However, it is unclear how the position of single-base deletions within the CEL VNTR affects pathogenic properties of the protein. Here, we investigated four naturally occurring CEL variants, arising from single-base deletions in different VNTR segments (DEL1, DEL4, DEL9, and DEL13). When the four variants were expressed in human embryonic kidney 293 cells, only DEL1 and DEL4 led to significantly reduced secretion, increased intracellular aggregation, and increased endoplasmic reticulum stress compared with normal CEL protein. The level of O-glycosylation was affected in all DEL variants. Moreover, all variants had enzymatic activity comparable with that of normal CEL. We conclude that the longest aberrant protein tails, resulting from single-base deletions in the proximal VNTR segments, have highest pathogenic potential, explaining why DEL1 and DEL4 but not DEL9 and DEL13 have been observed in patients with MODY8. These findings further support the view that CEL mutations cause pancreatic disease through protein misfolding and proteotoxicity, leading to endoplasmic reticulum stress and activation of the unfolded protein response.

Functional Genomics in Pancreatic β Cells: Recent Advances in Gene Deletion and Genome Editing Technologies for Diabetes Research

The inheritance of variants that lead to coding changes in, or the mis-expression of, genes critical to pancreatic beta cell function can lead to alterations in insulin secretion and increase the risk of both type 1 and type 2 diabetes. Recently developed clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene editing tools provide a powerful means of understanding the impact of identified variants on cell function, growth, and survival and might ultimately provide a means, most likely after the transplantation of genetically "corrected" cells, of treating the disease. Here, we review some of the disease-associated genes and variants whose roles have been probed up to now. Next, we survey recent exciting developments in CRISPR/Cas9 technology and their possible exploitation for β cell functional genomics. Finally, we will provide a perspective as to how CRISPR/Cas9 technology may find clinical application in patients with diabetes.

A tale of two pancreases: exocrine pathology and endocrine dysfunction

The islets of Langerhans are well embedded within the exocrine pancreas (the latter comprised of ducts and acini), but the nature of interactions between these pancreatic compartments and their role in determining normal islet function and survival are poorly understood. However, these interactions appear to be critical, as when pancreatic exocrine disease occurs, islet function and insulin secretion frequently decline to the point that diabetes ensues, termed pancreatogenic diabetes. The most common forms of pancreatogenic diabetes involve sustained exocrine disease leading to ductal obstruction, acinar inflammation, and fibro-fatty replacement of the exocrine pancreas that predates the development of dysfunction of the endocrine pancreas, as seen in chronic pancreatitis-associated diabetes and cystic fibrosis-related diabetes and, more rarely, MODY type 8. Intriguingly, a form of tumour-induced diabetes has been described that is associated with pancreatic ductal adenocarcinoma. Here, we review the similarities and differences among these forms of pancreatogenic diabetes, with the goal of highlighting the importance of exocrine/ductal homeostasis for the maintenance of pancreatic islet function and survival and to highlight the need for a better understanding of the mechanisms underlying these diverse conditions. Graphical abstract.

Single nucleotide polymorphisms in CEL-HYB1 increase risk for chronic pancreatitis through proteotoxic misfolding

Genetic variants contribute to the risk of chronic pancreatitis (CP) in adults and children. The risk variant CEL-HYB1, a recombinant hybrid allele of CEL and its neighboring pseudogene (CELP), encodes a pathogenic variant of the pancreatic digestive enzyme carboxyl ester lipase (CEL). We previously identified combinations of two non-synonymous SNPs, c.1463T>C (p. Ile488Thr) and c.1643C>T (p. Thr548Ile), in the break point region of CEL-HYB1. Herein, we tested whether these missense variants alter CP risk and their impact on functional properties of the CEL-HYB1 protein. Examination of CEL-HYB1 haplotypes in European patients and controls revealed that the combinationThr488-Ile548 was present only in cases (p ≤ .001). The lipase activity of purified recombinant CEL-HYB1 variants showed normal or near normal activity. CEL-HYB variants expressed in HEK293T cells all had decreased secretion compared with CEL, formed intracellular protein aggregates, and triggered endoplasmic reticulum stress. Thus, we propose that the presence of missense variants in CEL-HYB increases the pathogenicity of CEL-HYB1 through misfolding and gain-of-function proteotoxicity. Interestingly, Thr488-Ile548 and Thr488-Thr548 were equally pathogenic in the functional assays even though only the Thr488-Ile548 haplotype was significantly enriched in cases. The explanation for the mismatch between genetic and functional data requires further investigation.

Molecular Genetic Study in a Cohort of Iranian Families Suspected to Maturity-Onset Diabetes of the Young, Reveals a Recurrent Mutation and a High-Risk Variant in the CEL Gene

Background

Diabetes mellitus (DM) is a group of metabolic disorders in the body, accompanied with increasing blood sugar levels. Diabetes is classified into three groups: Type 1 DM (T1DM), Type 2 DM (T2DM), and monogenic diabetes. Maturity-onset diabetes of the young (MODY) is a monogenic diabetes that is frequently mistaken for T1D or T2D. The aim of this study was to diagnose MODY and its subtype frequency in a diabetic population in Iran.

Materials and Methods

In this study among ten diabetic families that were highly suspected to MODY by nongenetic biomarkers and without any pathogenic mutation in GCK and HNF1A genes, two patients from two unrelated families were examined via whole-exome sequencing (WES) in order to detect the causative gene of diabetes. Co-segregation analysis of the identified variant was performed using Sanger sequencing.

Results

In this study, no pathogenic variant was found in GCK and HNF1A genes (MODY2 and MODY3), while these two types of MODY were introduced as the most frequent in other studies. By using WES, a pathogenic variant (p.I488T) was found in one of the patients in CEL gene causing MODY8 that its frequency is very rare in other studied populations. A high-risk variant associated with diabetes was found in another patient.

Conclusion

WES was applied in this study to reveal the cause of MODY in 1 family. This pathogenic mutation was previously reported as a disease causing mutation.

International Consensus Guidelines for Risk Factors in Chronic Pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club

BACKGROUND

Chronic pancreatitis (CP) is a complex inflammatory disease with remarkably impaired quality of life and permanent damage of the pancreas. This paper is part of the international consensus guidelines on CP and presents the consensus on factors elevating the risk for CP.

METHODS

An international working group with 20 experts on CP from the major pancreas societies (IAP, APA, JPS, and EPC) evaluated 14 statements generated from evidence on four questions deemed to be the most clinically relevant in CP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available per statement. To determine the level of agreement, the working group voted on the 14 statements for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient.

RESULTS

Strong consensus and agreement were obtained for the following statements: Alcohol, smoking, and certain genetic alterations are risk factors for CP. Past history, family history, onset of symptoms, and life-style factors including alcohol intake and smoking history should be determined. Alcohol consumption dose-dependently elevates the risk of CP up to 4-fold. Ever smokers, even smoking less than a pack of cigarettes per day, have an increased risk for CP, as compared to never smokers.

CONCLUSIONS

Both genetic and environmental factors can markedly elevate the risk for CP. Therefore, health-promoting lifestyle education and in certain cases genetic counselling should be employed to reduce the incidence of CP.

Characterization of CEL-DUP2: Complete duplication of the carboxyl ester lipase gene is unlikely to influence risk of chronic pancreatitis

BACKGROUND/OBJECTIVES

Carboxyl ester lipase is a pancreatic enzyme encoded by CEL, an extremely polymorphic human gene. Pathogenic variants of CEL either increases the risk for chronic pancreatitis (CP) or cause MODY8, a syndrome of pancreatic exocrine and endocrine dysfunction. Here, we aimed to characterize a novel duplication allele of CEL (CEL-DUP2) and to investigate whether it associates with CP or pancreatic cancer.

METHODS

The structure of CEL-DUP2 was determined by a combination of Sanger sequencing, DNA fragment analysis, multiplex ligation-dependent probe amplification and whole-genome sequencing. We developed assays for screening of CEL-DUP2 and analyzed cohorts of idiopathic CP, alcoholic CP and pancreatic cancer. CEL protein expression was analyzed by immunohistochemistry.

RESULTS

CEL-DUP2 consists of an extra copy of the complete CEL gene. The allele has probably arisen from non-allelic, homologous recombination involving the adjacent pseudogene of CEL. We found no association between CEL-DUP2 carrier frequency and CP in cohorts from France (cases/controls: 2.5%/2.4%; P = 1.0), China (10.3%/8.1%; P = 0.08) or Germany (1.6%/2.3%; P = 0.62). Similarly, no association with disease was observed in alcohol-induced pancreatitis (Germany: 3.2%/2.3%; P = 0.51) or pancreatic cancer (Norway; 2.5%/3.2%; P = 0.77). Notably, the carrier frequency of CEL-DUP2 was more than three-fold higher in Chinese compared with Europeans. CEL protein expression was similar in tissues from CEL-DUP2 carriers and controls.

CONCLUSIONS

Our results support the contention that the number of CEL alleles does not influence the risk of pancreatic exocrine disease. Rather, the pathogenic CEL variants identified so far involve exon 11 sequence changes that substantially alter the protein's tail region.

Pathogenic Carboxyl Ester Lipase (CEL) Variants Interact with the Normal CEL Protein in Pancreatic Cells

Mutations in the gene encoding the digestive enzyme carboxyl ester lipase (CEL) are linked to pancreatic disease. The CEL variant denoted CEL-HYB predisposes to chronic pancreatitis, whereas the CEL-MODY variant causes MODY8, an inherited disorder of endocrine and exocrine pancreatic dysfunction. Both pathogenic variants exhibit altered biochemical and cellular properties compared with the normal CEL protein (CEL-WT, wild type). We here aimed to investigate effects of CEL variants on pancreatic acinar and ductal cell lines. Following extracellular exposure, CEL-HYB, CEL-MODY, and CEL-WT were endocytosed. The two pathogenic CEL proteins significantly reduced cell viability compared with CEL-WT. We also found evidence of CEL uptake in primary human pancreatic acinar cells and in native ductal tissue. Moreover, coexpression of CEL-HYB or CEL-MODY with CEL-WT affected secretion of the latter, as CEL-WT was observed to accumulate intracellularly to a higher degree in the presence of either pathogenic variant. Notably, in coendocytosis experiments, both pathogenic variants displayed a modest effect on cell viability when CEL-WT was present, indicating that the normal protein might diminish toxic effects conferred by CEL-HYB and CEL-MODY. Taken together, our findings provide valuable insight into how the pathogenic CEL variants predispose to pancreatic disease and why these disorders develop slowly over time.

Natural history of SPINK1 germline mutation related-pancreatitis

BACKGROUND

The aim was to describe genetic, clinical and morphological features in a large, multicentre European cohort of patients with SPINK1 related pancreatitis, in comparison with patients with idiopathic pancreatitis (IP).

METHODS

All SPINK1 mutation carriers with pancreatic symptoms from two French and one English centers were included. Patients with IP were included in a control group. Genetic, clinical, radiological and biochemical data were collected.

FINDINGS

209 and 302 patients were included in the SPINK1 and control groups (median follow-up: 8.3 years (3.7-17.4) vs 5.3 (2.5-8.8)). The median age at onset of symptoms was 20.1 years (17.5-22.8) in the SPINK1 group versus 41.2 (35.2-45.2). The age of exocrine pancreatic insufficiency (EPI) onset in the SPINK1 group was 49.5 (44.5-54.6) years vs. 65.2 (62.1-68.3), p < 0.001. SPINK1 patients with EPI were 5.3%, 14.7%, 28.3% and 52.4% at 20, 30, 40 and 50 years. Diabetes occurred 37.7 (33.3-42.1) years following the onset of symptoms in the SPINK1 group vs. 30.6 (17.3-43.8) (p = 0.002). SPINK1 patients with diabetes were 7.8%, 13.4%, 26.3% and 43.4% at 30, 40, 50 and 60 years. Seven patients (3.3%) developed pancreatic cancer in the SPINK1 group (versus 3 (0.99%), p = 0.1), at a median age of 60 vs 66 years. The cancer risk was 0.8% before 50 years, 11.9%, 27.7%, 51.8% at 60, 70 and 80 years and was 12 times higher than in controls (Cox HR 12.0 (3.0-47.8), p < 0.001).

INTERPRETATION

SPINK1 related pancreatitis is associated with earlier onset and pancreatic insufficiencies. p.N34S SPINK1 may well be associated with cancer.

A new prognostic factor of breast cancer: High carboxyl ester lipase expression related to poor survival

OBJECTIVE

The enzyme carboxyl ester lipase (CEL), known as bile salt-dependent lipase (BSDL) or bile salt-stimulated lipase (BSSL), is mainly expressed in pancreatic acinar cells and lactating mammary glands. To investigate the link between CEL expression of breast cancer (BC) tissues and the survival of BC patients by analyzing The Cancer Genome Atlas Breast Carcinoma (TCGA-BRCA) level 3 data.

METHODS

The clinical information and RNA-sequencing (RNA-Seq) expression data were downloaded from TCGA. Patients were divided into a high CEL expression group and a low CEL expression group using the optimal cutoff value (5.611) identified from the ROC curve. Chi-square test and Fisher exact test were used to find the correlation between the expression of CEL and clinicopathologic features. To assess the diagnostic capability, the receiver operating characteristic (ROC) curve of CEL was drawn. The survival differences between high and low CEL expression groups were compared by Cox regression analysis. Log-rank test was applied to the calculation of p values and the comparison of the Kaplan-Meier curves. Furthermore, Gene Expression Omnibus (GEO) datasets were used for external data validation.

RESULTS

Analysis of 1104 cases of tumor data showed that CEL was over-expressed in breast cancer. There were relationships between high CEL expression and clinicopathologic features. The high CEL expression group had a lower survival. By analyzing the area under the ROC curve (AUC) of CEL, it was found to have a limited diagnostic capability. CEL expression may be an independent prognostic factor for breast cancer survival through the multivariate analysis. The validation in GEO datasets also showed that CEL expression was higher in breast tumor tissues than in normal breast tissues. High CEL expression was associated with the poor overall survival of breast cancer.

CONCLUSIONS

High CEL expression may be an independent prognostic factor for the poor survival of breast cancer.

Protease-Sensitive Pancreatic Lipase Variants Are Associated With Early Onset Chronic Pancreatitis

OBJECTIVES

Premature activation of the digestive protease trypsin within the pancreatic parenchyma is a critical factor in the pathogenesis of pancreatitis. Alterations in genes that affect intrapancreatic trypsin activity are associated with chronic pancreatitis (CP). Recently, carboxyl ester lipase emerged as a trypsin-independent risk gene. Here, we evaluated pancreatic lipase (PNLIP) as a potential novel susceptibility gene for CP.

METHODS

We analyzed all 13 PNLIP exons in 429 nonalcoholic patients with CP and 600 control subjects from Germany, in 632 patients and 957 controls from France, and in 223 patients and 1,070 controls from Japan by DNA sequencing. Additionally, we analyzed selected exons in further 545 patients with CP and 1,849 controls originating from Germany, United States, and India. We assessed the cellular secretion, lipase activity, and proteolytic stability of recombinant PNLIP variants.

RESULTS

In the German discovery cohort, 8/429 (1.9%) patients and 2/600 (0.3%) controls carried a PNLIP missense variant (P = 0.02, odds ratio [OR] = 5.7, 95% confidence interval [CI] = 1.1-38.9). Variants detected in patients were prone to proteolytic degradation by trypsin and chymotrypsin. In the French replication cohort, protease-sensitive variants were also enriched in patients with early-onset CP (5/632 [0.8%]) vs controls (1/957 [0.1%]) (P = 0.04, OR = 7.6, 95% CI = 0.9-172.9). In contrast, we detected no protease-sensitive variants in the non-European populations. In the combined European data, protease-sensitive variants were found in 13/1,163 cases (1.1%) and in 3/3,000 controls (0.1%) (OR = 11.3, 95% CI = 3.0-49.9, P < 0.0001).

CONCLUSIONS

Our data indicate that protease-sensitive PNLIP variants are novel genetic risk factors for the development of CP.

The hybrid allele 1 of carboxyl-ester lipase (CEL-HYB1) in Polish pediatric patients with chronic pancreatitis

OBJECTIVES

It has previously been reported in a European case-control study with patients from Germany and France that CEL-HYB1, a hybrid allele of the carboxyl ester lipase (CEL) gene and its pseudogene CELP, increases susceptibility to chronic pancreatitis (CP). Here, we aimed to replicate this finding in Polish pediatric patients with CP.

METHOD

The distribution of the CEL-HYB1 allele in a CP pediatric cohort (n = 147, median age at CP onset 7.6 years) with no history of alcohol/smoking abuse was compared with ethnically matched healthy controls (n = 500, median age 46 years). Screening was performed using long-range PCR followed by agarose gel-electrophoresis.

RESULTS

We observed no significant difference in the carrier frequency of the CEL-HYB1 allele between CP patients (7/147, 4.8%) and controls (12/500, 2.4%; P = 0.16).

CONCLUSIONS

This study found no statistically significant association between CEL-HYB1 and chronic pancreatitis in a cohort of Polish pediatric CP patients.

Precision medicine in type 2 diabetes

The Precision Medicine Initiative defines precision medicine as 'an emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment and lifestyle for each person'. This approach will facilitate more accurate treatment and prevention strategies in contrast to a one-size-fits-all approach, in which disease treatment and prevention strategies are developed for generalized usage. Diabetes is clearly more heterogeneous than the conventional subclassification into type 1 and type 2 diabetes. Monogenic forms of diabetes like MODY and neonatal diabetes have paved the way for precision medicine in diabetes, as carriers of unique mutations require unique treatment. Diagnosis of diabetes in the past has been dependent upon measuring one metabolite, glucose. By instead including six variables in a clustering analysis, we could break down diabetes into five distinct subgroups, with better prediction of disease progression and outcome. The severe insulin-resistant diabetes (SIRD) cluster showed the highest risk of kidney disease and highest prevalence of nonalcoholic fatty liver disease, whereas patients in the insulin-deficient cluster 2 (SIDD) had the highest risk of retinopathy. In the future, this will certainly be improved and expanded by including genetic, epigenetic and other biomarker to allow better prediction of outcome and choice of more precise treatment.

The mucinous domain of pancreatic carboxyl-ester lipase (CEL) contains core 1/core 2 O-glycans that can be modified by ABO blood group determinants

Carboxyl-ester lipase (CEL) is a pancreatic fat-digesting enzyme associated with human disease. Rare mutations in the CEL gene cause a syndrome of pancreatic exocrine and endocrine dysfunction denoted MODY8, whereas a recombined CEL allele increases the risk for chronic pancreatitis. Moreover, CEL has been linked to pancreatic ductal adenocarcinoma (PDAC) through a postulated oncofetal CEL variant termed feto-acinar pancreatic protein (FAPP). The monoclonal antibody mAb16D10 was previously reported to detect a glycotope in the highly O-glycosylated, mucin-like C terminus of CEL/FAPP. We here assessed the expression of human CEL in malignant pancreatic lesions and cell lines. CEL was not detectably expressed in neoplastic cells, implying that FAPP is unlikely to be a glycoisoform of CEL in pancreatic cancer. Testing of the mAb16D10 antibody in glycan microarrays then demonstrated that it recognized structures containing terminal GalNAc-α1,3(Fuc-α1,2)Gal (blood group A antigen) and also repeated protein sequences containing GalNAc residues linked to Ser/Thr (Tn antigen), findings that were supported by immunostainings of human pancreatic tissue. To examine whether the CEL glycoprotein might be modified by blood group antigens, we used high-sensitivity MALDI-TOF MS to characterize the released O-glycan pool of CEL immunoprecipitated from human pancreatic juice. We found that the O-glycome of CEL consisted mainly of core 1/core 2 structures with a composition depending on the subject's FUT2 and ABO gene polymorphisms. Thus, among digestive enzymes secreted by the pancreas, CEL is a glycoprotein with some unique characteristics, supporting the view that it could serve additional biological functions to its cholesteryl esterase activity in the duodenum.