Gastroenterology Commons^™

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …

Mutant Kras Alters Extracellular Vesicle Microrna Sorting In Pancreatic Cystic Neoplasms, Rachel L. Dittmar

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers by organ site with a 5-year survival rate of just 10.8%. This is largely because most patients do not experience symptoms until the disease has already metastasized. The best hope to cure PDAC is surgery, which can only be done with a curative intent at an early stage when the disease is localized. There are no reliable circulating, body-fluid-based biomarkers to detect early stage PDAC or its precursor lesions in a timely manner for effective surgical intervention. When potential PDAC precursor lesions, such as mucinous pancreatic cysts are found, there are …

Mucosal Genomics Implicate Lymphocyte Activation And Lipid Metabolism In Refractory Environmental Enteric Dysfunction, Najeeha Talat Iqbal, Najeeb Rahman, Kamran Sadiq, Zubair Ahmad, Romana Idress, Junaid Iqbal, Sheraz Ahmed, Aneeta Hotwani, Fayyaz Umrani, Sana Syed, Syed Asad Ali

Department of Paediatrics and Child Health

Background & aims: Environmental enteric dysfunction (EED) limits the Sustainable Development Goals of improved childhood growth and survival. We applied mucosal genomics to advance our understanding of EED.
Methods: The Study of Environmental Enteropathy and Malnutrition (SEEM) followed 416 children from birth to 24 months in a rural district in Pakistan. Biomarkers were measured at 9 months and tested for association with growth at 24 months. The duodenal methylome and transcriptome was determined in 52 undernourished SEEM participants and 42 North American controls and celiac disease patients.
Results: After accounting for growth at study entry, circulating IGF-1 and ferritin predicted …

Micom: Metagenome-Scale Modeling To Infer Metabolic Interactions In The Gut Microbiota., Christian Diener, Sean M Gibbons, Osbaldo Resendis-Antonio

Articles, Abstracts, and Reports

Compositional changes in the gut microbiota have been associated with a variety of medical conditions such as obesity, Crohn's disease, and diabetes. However, connecting microbial community composition to ecosystem function remains a challenge. Here, we introduce MICOM, a customizable metabolic model of the human gut microbiome. By using a heuristic optimization approach based on L2 regularization, we were able to obtain a unique set of realistic growth rates that corresponded well with observed replication rates. We integrated adjustable dietary and taxon abundance constraints to generate personalized metabolic models for individual metagenomic samples. We applied MICOM to a balanced cohort of …

Genetic Evolution And Prognostic Determinants Of Pancreatic Cancer On Longitudinal Liquid Biopsies, Vincent Bernard

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) has one of the lowest 5-year survival rates amongst solid tumors. As early detection of PDAC is unusual and typically incidental, most patients present with locally advanced and metastatic disease where effective therapeutic strategies remain a significant unmet need. Specifically, surrogate biomarkers for tumor monitoring of PDAC may lead to improved elucidation of clinical actionability and prognostic potential. On the other hand, tumor tissue is rarely sampled in patients presenting with de novo or recurrent metastatic PDAC, apart from a fine needle aspiration or a core needle biopsy performed for diagnosis. This precludes the opportunity for …

Spontaneous Dna Damage To The Nuclear Genome Promotes Senescence, T Redox Imbalance And Aging, Andria R. Robinson, Matthew J. Yousefzadeh, Tania A. Rozgaja, Jin Wang, Xuesen Li, Jeremy S. Tilstra, Chelsea H. Feldman, Siobhan Q. Gregg, Caroline H. Johnson, Erin M. Skoda, Marie-Celine Frantz, Harris Bell-Temin, Hannah Pope-Varsalona, Aditi U. Gurkar, Luigi A. Nasto, Rena A.S. Robinson, Heike Fuhrmann-Stroissnigg, Jolanta Czerwinska, Sara J. Mcgowan, Nadiezhda Cantu-Madellin, Jamie B. Harris, Salony Maniar, Mark A. Ross, Christy E. Trussoni, Nicholas F. Larusso, Eugenia Cifuentes-Pagano, Patrick J. Pagano, Barbara Tudek, Nam V. Vo, Lora H. Rigatti, Patricia L. Opresko, Donna B. Stolz, Simon C. Watkins, Christin E. Burd, Claudette M. St, Croix, Gary Siuzdak, Nathan A. Yates, Paul D. Robbins, Yinsheng Wang, Peter Wipf, Eric E. Kelley, Laura J. Neidernhofer

Faculty & Staff Scholarship

Accumulation of senescent cells over time contributes to aging and age-related diseases. However, what drives senescence in vivo is not clear. Here we used a genetic approach to determine if spontaneous nuclear DNA damage is sufficient to initiate senescence in mammals. Ercc1-/Δ mice with reduced expression of ERCC1-XPF endonuclease have impaired capacity to repair the nuclear genome. Ercc1-/Δ mice accumulated spontaneous, oxidative DNA damage more rapidly than wild-type (WT) mice. As a consequence, senescent cells accumulated more rapidly in Ercc1-/Δ mice compared to repair-competent animals. However, the levels of DNA damage and senescent cells in Ercc1-/Δ mice never exceeded that …

Screening Of Exosomal Micrornas From Colorectal Cancer Cells, Cillian Clancy, Sonja Khan, Claire L. Glynn, Emma Holian, Peter Dockery, Pierce Lalor, James A.L. Brown, Myles Joyce, Michael J. Kerin, Roisin M. Dwyer

Forensic Science Publications

BACKGROUND: Cells release extracellular membrane vesicles including microvesicles known as exosomes. Exosomes contain microRNAs (miRNAs) however the full range within colorectal cancer cell secreted exosomes is unknown. OBJECTIVE: To identify the full range of exosome encapsulated miRNAs secreted from 2 colorectal cancer cell lines and to investigate engineering of exosomes over-expressing miRNAs. METHODS: Exosomes were isolated from HCT-116 and HT-29 cell lines. RNA was extracted from exosomes and microRNA array performed. Cells were engineered to express miR-379 (HCT-116-379) or a non-targeting control (HCT-116-NTC) and functional effects were determined. Exosomes secreted by engineered cells were transferred to recipient cells and the …

Increased Number Of Circulating Exosomes And Their Microrna Cargos Are Potential Novel Biomarkers In Alcoholic Hepatitis, Fatemeh Momen-Heravi, Banishree Saha, Karen Kodys, Donna Catalano, Abhishek Satishchandran, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: It has been well documented that alcohol and its metabolites induce injury and inflammation in the liver. However, there is no potential biomarker to monitor the extent of liver injury in alcoholic hepatitis patients. MicroRNAs (miRNAs) are a class of non-coding RNAs that are involved in various physiologic and pathologic processes. In the circulation, a great proportion of miRNAs is associated with extracellular vesicles (EVs)/exosomes. Here, we hypothesized that the exosome-associated miRNAs can be used as potential biomarkers in alcoholic hepatitis (AH).

METHODS: Exosomes were isolated from sera of alcohol-fed mice or pair-fed mice, and plasma of alcoholic hepatitis …

The Genetics Of Hepatitis C Virus Underlie Its Ability To Escape Humoral Immunity, Jay Kolls, Gyongyi Szabo

Gyongyi Szabo

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, and efforts to develop therapeutic vaccine strategies have been limited by immune escape due to HCV variants that are resistant to current vaccines or HCV variants that rapidly acquire new resistance-conferring mutations. Recently, the crystal structure of the viral envelope protein E2 region was resolved as well as how E2 docks to the host CD81 protein; therefore, antibodies that block this interaction should prevent viral entry into host cells. In this issue of the JCI, Bailey and colleagues show that immune escape of HCV can occur by naturally …

Sting-Irf3 Pathway Links Endoplasmic Reticulum Stress With Hepatocyte Apoptosis In Early Alcoholic Liver Disease, Jan Petrasek, Arvin Iracheta-Vellve, Timea Csak, Abhishek Satishchandran, Karen Kodys, Evelyn A. Kurt-Jones, Katherine A. Fitzgerald, Gyongyi Szabo

Katherine A. Fitzgerald

Emerging evidence suggests that innate immunity drives alcoholic liver disease (ALD) and that the interferon regulatory factor 3 (IRF3),a transcription factor regulating innate immune responses, is indispensable for the development of ALD. Here we report that IRF3 mediates ALD via linking endoplasmic reticulum (ER) stress with apoptotic signaling in hepatocytes. We found that ethanol induced ER stress and triggered the association of IRF3 with the ER adaptor, stimulator of interferon genes (STING), as well as subsequent phosphorylation of IRF3. Activated IRF3 associated with the proapoptotic molecule Bax [B-cell lymphoma 2 (Bcl2)-associated X protein] and contributed to hepatocyte apoptosis. Deficiency of …

Microrna-122 Regulates Hypoxia-Inducible Factor-1 And Vimentin In Hepatocytes And Correlates With Fibrosis In Diet-Induced Steatohepatitis, Timea Csak, Shashi Bala, Dora Lippai, Abhishek Satishchandran, Donna Catalano, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: miR-122 is the most abundant miRNA in the liver particularly in hepatocytes where it targets cholesterol metabolism. Steatosis, a key component of non-alcoholic fatty liver disease, is regulated by hypoxia-inducible factor-1alpha (HIF-1alpha). Here, we hypothesized that reduced miR-122 has a pathogenic role in steatohepatitis. METHODS: miR-122 and its target genes were evaluated in mouse livers and/or isolated hepatocytes after methionine-choline-deficient (MCD) or methionine-choline-supplemented (MCS) diet. RESULTS: Liver and hepatocyte miR-122 expression was significantly decreased in steatohepatitis. A maximum reduction in miR-122 occurred at the fibrosis stage (8 weeks of MCD diet). MAP3K3, a miR-122 target gene, was …

Chronic Alcohol-Induced Microrna-155 Contributes To Neuroinflammation In A Tlr4-Dependent Manner In Mice, Dora Lippai, Shashi Bala, Timea Csak, Evelyn A. Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

INTRODUCTION: Alcohol-induced neuroinflammation is mediated by pro-inflammatory cytokines and chemokines including tumor necrosis factor-alpha (TNFalpha), monocyte chemotactic protein-1 (MCP1) and interleukin-1-beta (IL-1beta). Toll-like receptor-4 (TLR4) pathway induced nuclear factor-kappaB (NF-kappaB) activation is involved in the pathogenesis of alcohol-induced neuroinflammation. Inflammation is a highly regulated process. Recent studies suggest that microRNAs (miRNAs) play crucial role in fine tuning gene expression and miR-155 is a major regulator of inflammation in immune cells after TLR stimulation. AIM: To evaluate the role of miR-155 in the pathogenesis of alcohol-induced neuroinflammation. METHODS: Wild type (WT), miR-155- and TLR4-knockout (KO) mice received 5% ethanol-containing or isocaloric …

Human Ezrin-Moesin-Radixin Proteins Modulate Hepatitis C Virus Infection, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Host cytoskeletal proteins of the ezrin-moesin-radixin (EMR) family have been shown to modulate single-stranded RNA virus infection through regulating stable microtubule formation. Antibody engagement of CD81, a key receptor for hepatitis C virus (HCV) entry, induces ezrin phosphorylation. Here we tested the role of EMR proteins in regulating HCV infection and explored potential therapeutic targets. We show that HCV E2 protein induces rapid ezrin phosphorylation and its cellular redistribution with F-actin by way of spleen tyrosine kinase (SYK). Therapeutically blocking the functional roles of SYK or F-actin reorganization significantly reduced Huh7.5 cell susceptibility to HCV J6/JFH-1 infection. Using gene regulation, …

Micro-Rna-155 Deficiency Prevents Alcohol-Induced Serum Endotoxin Increase And Small Bowel Inflammation In Mice, Dora Lippai, Shashi Bala, Donna Catalano, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Chronic alcohol impairs gut barrier function and induces inflammatory cytokines. The effects of acute alcohol binge on the gut are partially understood. Micro-RNA-155 (miR-155), a modulator of cytokine and T-cell immune response in the gut, stabilizes tumor necrosis factor-alpha (TNFalpha) mRNA. Here, we investigated the role of the inflammation modulator miR-155 as well as the effects of acute binge and chronic alcohol feeding in the small bowel (SB) in mice. METHODS: For the acute alcohol binge, wild-type (WT) mice received 5 g/kg 50% alcohol/d or equal amount of water oral gavage for 3 days. WT and miR-155-deficient (miR-155-knockout [KO]) …

Both Bone Marrow-Derived And Non-Bone Marrow-Derived Cells Contribute To Aim2 And Nlrp3 Inflammasome Activation In A Myd88-Dependent Manner In Dietary Steatohepatitis, Timea Csak, Arun Pillai, Michal Ganz, Dora Lippai, Jan Petrasek, Jin-Kyu Park, Karen Kodys, Angela Dolganiuc, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: Inflammation promotes the progression of non-alcoholic steatohepatitis (NASH). Toll-like receptor 4 (TLR4) and TLR9 activation through myeloid differentiation primary response gene 88 (MyD88) and production of mature interleukin-1beta (IL-1beta) via inflammasome activation contribute to steatohepatitis. Here, we investigated the inter-relationship between TLR signalling and inflammasome activation in dietary steatohepatitis.

METHODS: Wild type (WT), TLR4- and MyD88-deficient (KO) mice received methionine-choline-deficient (MCD) or -supplemented (MCS) diets for 5 weeks and a subset was challenged with TLR9 ligand CpG-DNA.

RESULTS: TLR4, TLR9, AIM2 (absent in melanoma 2) and NLRP3 (NLR family pyrin domain containing 3) inflammasome mRNA, and mature …

Exosome-Mediated Delivery Of Functionally Active Mirna-155 Inhibitor To Macrophages, Fatemeh Momen-Heravi, Shashi Bala, Terence Bukong, Gyongyi Szabo

Gyongyi Szabo

Exosomes, membranous nanovesicles, naturally carry bio-macromolecules and play pivotal roles in both physiological intercellular crosstalk and disease pathogenesis. Here, we showed that B cell-derived exosomes can function as vehicles to deliver exogenous miRNA-155 mimic or inhibitor into hepatocytes or macrophages, respectively. Stimulation of B cells significantly increased exosome production. Unlike in parental cells, baseline level of miRNA-155 was very low in exosomes derived from stimulated B cells. Exosomes loaded with a miRNA-155 mimic significantly increased miRNA-155 levels in primary mouse hepatocytes and the liver of miRNA-155 knockout mice. Treatment of RAW macrophages with miRNA-155 inhibitor loaded exosomes resulted in statistically …

Sting-Irf3 Pathway Links Endoplasmic Reticulum Stress With Hepatocyte Apoptosis In Early Alcoholic Liver Disease, Jan Petrasek, Arvin Iracheta-Vellve, Timea Csak, Abhishek Satishchandran, Karen Kodys, Evelyn A. Kurt-Jones, Katherine A. Fitzgerald, Gyongyi Szabo

Gyongyi Szabo

Emerging evidence suggests that innate immunity drives alcoholic liver disease (ALD) and that the interferon regulatory factor 3 (IRF3),a transcription factor regulating innate immune responses, is indispensable for the development of ALD. Here we report that IRF3 mediates ALD via linking endoplasmic reticulum (ER) stress with apoptotic signaling in hepatocytes. We found that ethanol induced ER stress and triggered the association of IRF3 with the ER adaptor, stimulator of interferon genes (STING), as well as subsequent phosphorylation of IRF3. Activated IRF3 associated with the proapoptotic molecule Bax [B-cell lymphoma 2 (Bcl2)-associated X protein] and contributed to hepatocyte apoptosis. Deficiency of …

Micrornas In Liver Disease, Gyongyi Szabo, Shashi Bala

Gyongyi Szabo

Small, noncoding microRNAs (miRNAs) regulate diverse biological functions in the liver and increasing evidence suggests that they have a role in liver pathology. This Review summarizes advances in the field of miRNAs in liver diseases, inflammation and cirrhosis. MicroRNA-122, the most abundant miRNA in hepatocytes, has well-defined roles in HCV replication, and data indicate that it also serves as a viable therapeutic target. The role of miR-122 is also emerging in other liver diseases. Ample evidence exists for the important regulatory potential of other miRNAs in conditions associated with liver inflammation related to alcohol use, the metabolic syndrome or autoimmune …

Mismatch Repair Deficient Tumors Lacking Known Sporadic Causes: Are They All Due To Lynch Syndrome?, Katherine M. Dempsey

Dissertations & Theses (Open Access)

BACKGROUND: Mismatch repair deficient (MMRD) colorectal (CRC) or endometrial (EC) cancers in the absence of MLH1 promoter hypermethylation and BRAF mutations are suggestive of Lynch syndrome (LS). Positive germline genetic test results confirm LS. It is unclear if individuals with MMRD tumors but no identified germline mutation or sporadic cause (MMRD+/germline-) have LS.

HYPOTHESIS: Since LS is hereditary, individuals with LS should have a stronger family history of LS-related cancers than individuals with sporadic tumors. We hypothesized that MMRD+/germline- CRC and/or EC patients would have less suggestive family histories than LS CRC and/or EC patients.

METHODS: 253 individuals with an …

Increased Microrna-155 Expression In The Serum And Peripheral Monocytes In Chronic Hcv Infection, Shashi Bala, Yaphet Tilahun, Odette Taha, Hawau Alao, Karen Kodys, Donna Catalano, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Hepatitis C Virus (HCV), a single stranded RNA virus, affects millions of people worldwide and leads to chronic infection characterized by chronic inflammation in the liver and in peripheral immune cells. Chronic liver inflammation leads to progressive liver damage. MicroRNAs (miRNA) regulate inflammation (miR-155, -146a and -125b) as well as hepatocyte function (miR-122). METHODS: Here we hypothesized that microRNAs are dysregulated in chronic HCV infection. We examined miRNAs in the circulation and in peripheral monocytes of patients with chronic HCV infection to evaluate if specific miRNA expression correlated with HCV infection. RESULTS: We found that monocytes from chronic HCV …

Serum Microrna-122 And Mir-155 As Biomarkers Of Liver Injury And Inflammation In Models Of Acute And Chronic Liver Disease, Shashi Bala, Jan Petrasek, Shiv Mundkur, Donna Catalano, Jeanine Ward, Ivan Levin, Hawau Alao, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Background: MicroRNAs (miRs) are small non-coding molecules that regulate gene expression. MiRs expression levels change not only in diseased tissues but also in circulation. Further, miRs are stable in frozen samples that make them attractive for biomarker discovery. Recent reports suggest altered expression of circulating miRNAs in various diseases. MiR-122 is highly abundant in hepatocytes where it regulates different metabolic pathways while miR-155 is a central regulator of inflammation. The aim of this study was to evaluate circulating miRNAs as potential markers of hepatocyte damage and inflammation in liver diseases. Methods: Serum/plasma and liver samples were collected from C57/BL6 mice …

Association Between Chronic Liver And Colon Inflammation During The Development Of Murine Syngeneic Graft-Versus-Host Disease, Jason Anthony Brandon, Jacqueline Perez-Rodriguez, C. Darrell Jennings, Donald A. Cohen, Vishal J. Sindhava, Subbarao Bondada, Alan M. Kaplan, J. Scott Bryson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The murine model of cyclosporine A (CsA)-induced syngeneic graft-versus-host disease (SGVHD) is a bone marrow (BM) transplantation model that develops chronic colon inflammation identical to other murine models of CD4⁺ T cell-mediated colitis. Interestingly, SGVHD animals develop chronic liver lesions that are similar to the early peribiliary inflammatory stages of clinical chronic liver disease, which is frequently associated with inflammatory bowel disease (IBD). Therefore, studies were initiated to investigate the chronic liver inflammation that develops in the SGVHD model. To induce SGVHD, mice were lethally irradiated, reconstituted with syngeneic BM, and treated with CsA. All of the SGVHD animals …

Elevated Tumor Necrosis Factor Alpha Production Concomitant To Elevated Prostaglandin E2 Production By Trauma Patients' Monocytes, Thomas Takayama, Carol Miller-Graziano, Gyongyi Szabo

Gyongyi Szabo

The level of tumor necrosis factor alpha (TNF alpha), a monokine implicated in mediating septic shock, is elevated in the blood of some patients with sepsis. Monocytes from 11 trauma patients and 11 burn patients were suboptimally stimulated with interferon gamma and muramyl dipeptide, an analogue of bacterial wall products. The patients with sepsis showed significantly greater total TNF alpha levels (secreted in combination with cell-associated) 3 days before septic episodes, as compared with normal controls (32.38 to 2231.76 ng/10(6) monocytes per milliliter, median = 121.03 ng/10(6) monocytes per milliliter; normal control: 0.00 to 18.20 ng/10(6) monocytes per milliliter, median …

Hepatitis C Core And Nonstructural 3 Proteins Trigger Toll-Like Receptor 2-Mediated Pathways And Inflammatory Activation, Angela Dolganiuc, Shilpa Oak, Karen Kodys, Douglas Golenbock, Robert Finberg, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND AND AIMS: Recent evidence suggests that toll-like receptors (TLRs) recognize certain viruses. We reported that hepatitis C virus (HCV) core and nonstructural 3 (NS3) proteins activate inflammatory pathways in monocytes. The aim of this study was to investigate the role of TLRs in innate immune cell activation by core and NS3 proteins. METHODS: Human monocytes, human embryonic kidney cells transfected with TLR2, and peritoneal macrophages from TLR2, MyD88 knockout, and wild-type mice were studied to determine intracellular signaling and proinflammatory cytokine induction by HCV proteins. RESULTS: HCV core and NS3 proteins triggered inflammatory cell activation via the pattern recognition …