Investigating the role of the basic helix-loop-helix transcription factor MIST1 in pancreatic diseases

Acinar cells of the exocrine pancreas are dedicated to synthesize, package and secrete immense quantities of pro-digestive enzymes to maintain proper metabolic homeostasis for the organism. Dysregulation of enzyme secretion in acinar cells can give rise to exocrine diseases including acute pancreatitis (AP), a disease that targets acinar cells, leading to acinar-ductal metaplasia (ADM), inflammation and fibrosis—events that can transition into the earliest stages of pancreatic ductal adenocarcinoma (PDAC). The focus of this thesis is to interrogate transcriptional regulatory networks that are susceptible to AP and the role that these networks play in acinar cell and exocrine pancreas responses. The overall goal is to determine the importance of the acinar-specific maturation transcription factor MIST1 to AP damage and organ recovery and its role in AP induced PDAC upon oncogenic transformation. Analysis of wild-type and Mist1 conditional null mice revealed that Mist1 gene transcription and protein accumulation are dramatically reduced as acinar cells undergo ADM alterations during AP episodes. To test if loss of MIST1 function is primarily responsible for the damaged status of the organ, mice harboring a Cre-inducible Mist1transgene (iMist1) were utilized to determine if sustained MIST1 activity could alleviate AP damage responses. Surprisingly, constitutive iMist1 expression during AP produced a dramatic increase in organ damage followed by acinar cell death. This result suggests that the transient silencing of Mist1 expression is critical for acinar cells to survive an AP episode, providing cells an opportunity to suppress their secretory function and regenerate damaged cells. In order to further define the role of MIST1 in pancreatic neoplasia lesion formation (a precursor of PDAC), Mist1 conditional null mice were generated that contained a mutated oncogenic KrasG12D allele. Direct comparison between embryonic Mist1 null mice with conditional Mist1 null mice in the context of KRASG12D activity demonstrated that embryonic Mist1 null mice are more susceptible to PanIN formation. The importance of MIST1 to these events suggests that modulating key pancreas transcription networks could ease clinical symptoms in patients diagnosed with pancreatitis and pancreatic cancer

Silencing Mist1 gene expression is essential for recovery from acute pancreatitis

Acinar cells of the exocrine pancreas are tasked with synthesizing, packaging and secreting vast quantities of pro-digestive enzymes to maintain proper metabolic homeostasis for the organism. Because the synthesis of high levels of hydrolases is potentially dangerous, the pancreas is prone to acute pancreatitis (AP), a disease that targets acinar cells, leading to acinar-ductal metaplasia (ADM), inflammation and fibrosis-events that can transition into the earliest stages of pancreatic ductal adenocarcinoma. Despite a wealth of information concerning the broad phenotype associated with pancreatitis, little is understood regarding specific transcriptional regulatory networks that are susceptible to AP and the role these networks play in acinar cell and exocrine pancreas responses. In this study, we examined the importance of the acinar-specific maturation transcription factor MIST1 to AP damage and organ recovery. Analysis of wild-type and Mist1 conditional null mice revealed that Mist1 gene transcription and protein accumulation were dramatically reduced as acinar cells underwent ADM alterations during AP episodes. To test if loss of MIST1 function was primarily responsible for the damaged status of the organ, mice harboring a Cre-inducible Mist1 transgene (iMist1) were utilized to determine if sustained MIST1 activity could alleviate AP damage responses. Unexpectedly, constitutive iMist1 expression during AP led to a dramatic increase in organ damage followed by acinar cell death. We conclude that the transient silencing of Mist1 expression is critical for acinar cells to survive an AP episode, providing cells an opportunity to suppress their secretory function and regenerate damaged cells. The importance of MIST1 to these events suggests that modulating key pancreas transcription networks could ease clinical symptoms in patients diagnosed with pancreatitis and pancreatic cancer. © 2015 Karki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

A single transcription factor is sufficient to induce and maintain secretory cell architecture

We hypothesized that basic helix–loop–helix (bHLH) MIST1 (BHLHA15) is a “scaling factor” that universally establishes secretory morphology in cells that perform regulated secretion. Here, we show that targeted deletion of MIST1 caused dismantling of the secretory apparatus of diverse exocrine cells. Parietal cells (PCs), whose function is to pump acid into the stomach, normally lack MIST1 and do not perform regulated secretion. Forced expression of MIST1 in PCs caused them to expand their apical cytoplasm, rearrange mitochondrial/lysosome trafficking, and generate large secretory granules. Mist1 induced a cohort of genes regulated by MIST1 in multiple organs but did not affect PC function. MIST1 bound CATATG/CAGCTG E boxes in the first intron of genes that regulate autophagosome/lysosomal degradation, mitochondrial trafficking, and amino acid metabolism. Similar alterations in cell architecture and gene expression were also caused by ectopically inducing MIST1 in vivo in hepatocytes. Thus, MIST1 is a scaling factor necessary and sufficient by itself to induce and maintain secretory cell architecture. Our results indicate that, whereas mature cell types in each organ may have unique developmental origins, cells performing similar physiological functions throughout the body share similar transcription factor-mediated architectural “blueprints.

Bark Extract of Lantana camara in 1M HCl as Green Corrosion Inhibitor for Mild Steel

Lantana camara, an invasive species that adversely affects habitant, bioregions and environment has been studied as corrosion inhibitor. Methanolic extract of barks of Lantana camara in 1 M hydrochloric acid was tested as corrosion inhibitor on mild steel using potentiodynamic polarization technique. The corrosion inhibition efficiency of extract varied with concentration of extract and immersion of time. The inhibition was found to increase with increase in concentration of the extract. The polarization behavior of mild steel revealed that maximum inhibition efficiency is 97.33 % and 89.93 % respectively in the 1000 and 200 ppm concentration of the inhibitor respectively. The results showed that the extract of the barks of Lantana camara served as a mixed type inhibitor

Selection of study sites and participants for research into Nepal’s federal health system

Introduction: This article offers insights into the process of selecting representative study sites and participants in a longitudinal study in Nepal. As part of the research design process, the selection of representative areas in a large-scale study requires both intellectual and practical considerations. Methods: We briefly introduce our study into the impact of federalization on Nepal’s health system before outlining the criteria considered for the identification of fieldwork sites and the most appropriate study participants for the qualitative interviews and participatory components of this research. Findings: The selected areas are presented with an overview of the areas selected and their justification. The study sites and participants should consider a broader coverage with diverse participants’ backgrounds. Several factors can influence the identification and recruitment of the right participants, including the use of appropriate gatekeepers, gaining access to recruit participants, logistical challenges, and participant follow-up. Conclusion: We conclude that longitudinal qualitative research requires a carefully selected diverse set of study sites and participants to assess the complexities and dynamics of the health system and service provision to ensure that longitudinal research is representative and effective in addressing the research question(s) being investigated

Selection of study sites and participants for research into Nepal’s Federal Health System

Introduction: This article offers insights into the process of selecting representative study sites and participants in a longitudinal study in Nepal. As part of the research design process, the selection of representative areas in a large-scale study requires both intellectual and practical considerations. Methods: We briefly introduce our study into the impact of federalization on Nepal’s health system before outlining the criteria considered for the identification of fieldwork sites and the most appropriate study participants for the qualitative interviews and participatory components of this research. Findings: The selected areas are presented with an overview of the areas selected and their justification. The study sites and participants should consider a broader coverage with diverse participants’ backgrounds. Several factors can influence the identification and recruitment of the right participants, including the use of appropriate gatekeepers, gaining access to recruit participants, logistical challenges, and participant follow-up. Conclusion: We conclude that longitudinal qualitative research requires a carefully selected diverse set of study sites and participants to assess the complexities and dynamics of the health system and service provision to ensure that longitudinal research is representative and effective in addressing the research question(s) being investigated

Investigating the role of the basic helix-loop-helix transcription factor MIST1 in pancreatic diseases

Acinar cells of the exocrine pancreas are dedicated to synthesize, package and secrete immense quantities of pro-digestive enzymes to maintain proper metabolic homeostasis for the organism. Dysregulation of enzyme secretion in acinar cells can give rise to exocrine diseases including acute pancreatitis (AP), a disease that targets acinar cells, leading to acinar-ductal metaplasia (ADM), inflammation and fibrosis—events that can transition into the earliest stages of pancreatic ductal adenocarcinoma (PDAC). The focus of this thesis is to interrogate transcriptional regulatory networks that are susceptible to AP and the role that these networks play in acinar cell and exocrine pancreas responses. The overall goal is to determine the importance of the acinar-specific maturation transcription factor MIST1 to AP damage and organ recovery and its role in AP induced PDAC upon oncogenic transformation. Analysis of wild-type and Mist1 conditional null mice revealed that Mist1 gene transcription and protein accumulation are dramatically reduced as acinar cells undergo ADM alterations during AP episodes. To test if loss of MIST1 function is primarily responsible for the damaged status of the organ, mice harboring a Cre-inducible Mist1 transgene (iMist1) were utilized to determine if sustained MIST1 activity could alleviate AP damage responses. Surprisingly, constitutive iMist1 expression during AP produced a dramatic increase in organ damage followed by acinar cell death. This result suggests that the transient silencing of Mist1 expression is critical for acinar cells to survive an AP episode, providing cells an opportunity to suppress their secretory function and regenerate damaged cells. In order to further define the role of MIST1 in pancreatic neoplasia lesion formation (a precursor of PDAC), Mist1 conditional null mice were generated that contained a mutated oncogenic KrasG12D allele. Direct comparison between embryonic Mist1 null mice with conditional Mist1 null mice in the context of KRASG12D activity demonstrated that embryonic Mist1 null mice are more susceptible to PanIN formation. The importance of MIST1 to these events suggests that modulating key pancreas transcription networks could ease clinical symptoms in patients diagnosed with pancreatitis and pancreatic cancer

If You'll Be a Soldier I'll Be a Red Cross Nurse

First Line: She is the village beauty the little country prideFirst Line of Chorus: If you'll be a soldier then I'll follow youTitle of Larger Work: What Next?Key: E Flat Majo