Indiana University-Purdue University Indianapolis (IUPUI) / Traditionally, the exocrine and endocrine cellular compartments of the pancreas have been considered distinct functional systems. However, recent studies suggest a more intricate relationship between the exocrine and endocrine, which may impact pancreatic growth and health. Additionally, translational control mechanisms have been linked to organ development. Our lab has shown that the mRNA translation factor eukaryotic initiation factor 5A (eIF5A), when in its post-translationally modified “hypusinated” form, plays a role in pancreas development. The hypusination of eIF5A requires the rate-limiting enzyme deoxyhypusine synthase (Dhps) to post- translationally modify a critical lysine residue which in turn produces the active form of eIF5A that functions in mRNA translation. When we generated animals with a deletion of Dhps in the pancreatic progenitor cells, there was no alteration in islet mass but significant exocrine insufficiency at embryonic (E) day 18.5 concomitant with downregulation of proteins required for exocrine pancreas development and function. Resultantly these animals died by 6 weeks-of-age. These observations prompted the question, is the phenotype caused by the absence of hypusinated eIF5A or the increase of unhypusinated eIF5A? To address this, we generated a mouse model wherein Eif5a is deleted in the pancreas (eIF5A∆PANC) and these mutant animals also display exocrine insufficiency. Interestingly, beta cell mass is increased at E18.5, and the mutant animals maintain euglycemia and survive up to 2 years. Ongoing analyses are interrogating the differences between these animal models with the goal to determine if mRNA translation facilitates cellular communication between the exocrine and endocrine pancreas.

Pancreatic cancer is an abhorrent malignancy with limited diagnostics and response to drug therapy. It is believed that noncoding RNAs (ncRNAs) will further the understanding behind the mechanisms of pancreatic cancer development and progression, providing a novel approach for drug development and biomarker discovery. Therefore, a database of pancreatic cancer ncRNAs was established using bioinformatics and text mining approaches. These ncRNAs were characterized for RNA expression, copy number variation, disease association, single nucleotide polymorphisms, secretome analysis, and identification of protein targets. Exosomal proteins and ncRNA identified through this study provide the basis for noninvasive diagnostic potential. Additionally, a secreted microRNA, MIR3620, emerged from this study as a potential prognostic and diagnostic biomarker for pancreatic cancer. By analyzing MIR3620 and its protein targets, a mechanism of regulation for these genes in contributing to the progression and development of pancreatic cancer was established. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Diss. (sammanfattning)--Umeå : Umeå universitet, 2009. / Härtill 3 uppsatser.

Thesis (doctoral)--Rijksuniversiteit te Utrecht.

Orientador: César Tadeu Spadella / Resumo: Nas ressecções pancreáticas por pancreatite crônica, o pâncreas remanescente poderá sofrer novos surtos de pancreatite, em gravidade variável. Nas ressecções por tumores ou pancreatite, a mais comum complicação é a fístula pancreática, com suas conseqüentes morbidade e mortalidade. Nos transplantes pancreáticos, a drenagem da parte exócrina do enxerto para o intestino ou para a bexiga, além das peculiaridades técnicas da execução, não é isenta de diversas complicações. Visando evitar ou atenuar tais conseqüências e simplificar a técnica cirúrgica, têm sido usadas outras abordagens para o tratamento do coto/enxerto pancreático: drenagem livre das secreções com o ducto pancreático aberto, ligadura ductal e oclusão do ducto com polímeros. O propósito de nossa investigação foi estudar os efeitos clínicos, laboratoriais e histopatológicos destes procedimentos sobre os componentes endócrino e exócrino do pâncreas em coelhos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: After pancreatic ressections due to chronic pancreatitis the remnant pancreas can lead to new outbreaks of pancreatitis in variable degrees of severity. After the resections by tumors or pancreatitis, the most common complication are the pancreatic fistulas with their resultant morbidity and mortality. In the pancreas transplantation the bowel or bladder drainage of the exocrine part of the graft, beyond the technical peculiarities of the execution, is not exempt of several complications. In order to avoid or reduce such consequences and trying to simplify the surgical technique, there have been used other approaches for the treatment of the pancreatic stump/graft: free drainage of the secretions with the duct left open, ductal ligature and duct occlusion with polymers. The proposal of our investigation was to study the clinical, laboratorial and histopathological effects of these procedures in the endocrine and exocrine compounds of the rabbit pancreas... (Complete abstract, click electronic address below) / Doutor

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published_or_final_version / Medicine / Master / Doctor of Medicine

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Pancreatic ductal adenocarcinoma (PDAC) is a disease with very poor prognosis amongst all pancreatico-biliary cancers. PDAC is characterised by a pronounced desmoplastic stroma which upon depletion has been associated with immune cell mediated tumour clearance. In situ analyses of various immune cell markers in the stromal compartments may provide a lucid picture of immune cell migration to the tumour epithelia. Automated, unbiased, high throughput imaging and analysis of specifically designed tissue microarrays, from surgically resected tissue samples of PDAC, advanced PDAC, and other pancreatico-biliary diseases; stained for distinct immune cell markers was carried out in the juxtatumoural stroma and the panstromal compartments. Prognostic significance was determined with X-Tile software. In vitro and in vivo assays were undertaken to outline the possible mechanisms. Immune cell infiltration to PDAC was higher than infiltration to other pancreatico-biliary diseases with the exception of CD8+ T cells. While CD4+, CD68+ and myeloperoxidase+ cells could infiltrate the juxtatumoural stroma of PDAC; CD3+, CD8+, Foxp3+ and CD20+ cells could not in the early stage PDAC patients tissue analysed and also in an independent validation cohort of advanced stage PDAC patients. Survival analyses demonstrated pro-survival effects of having high CD8+ densities. CD8+ T cells could only infiltrate the juxtatumoural compartment of KPC mice after stromal collapse resulting from targeting stellate cells with All-trans Retinoic Acid. 17 In vitro migration assays demonstrated increased CD8+ T cell migration towards activated pancreatic stellate cells compared to quiescent pancreatic stellate cells and appeared to be dependent on CXCL12. T cells are hindered from migrating to the juxtatumoural compartment by activated pancreatic stellate cells as a result of an increase in CXCL12 secretion. Rendering activated pancreatic stellate cells quiescent results in a reduction of CXCL12 secretion which may allow CD8+ T cells to migrate to the tumours and perform cytotoxic functions.