Disruption of the gut epithelial barrier occurs commonly in various critical surgical conditions such as trauma, burns, hemorrhage, sepsis, and massive surgical operations, leading to the translocation of luminal toxic substances and bacteria to the blood stream. Since the exact mechanism underlying the acute epithelial barrier dysfunction remains obscure, effective therapies to preserve the integrity of the barrier are limited, contributing to death in critically surgical patients with leaky gut. During previous funding period, we have established that decreased expression of occludin and ZO-1 in the tight junction (TJ) and E-cadherin in the adherens junction (AJ) plays an important role in increased intestinal epithelial paracellular permeability, and have identified a novel mechanism through which cellular polyamines regulate transcription of the genes encoding these intercellular junctional proteins. However, the exact mechanism underlying posttranscriptional regulation of TJs and AJs in critical surgical conditions remains largely unknown and is the focus of this competitively renewal application. Our preliminary results indicate a) RNA-binding protein (RBP) HuR binds to the occludin mRNA, while HuR silencing represses occludin translation;b) HuR- binding affinity decreases significantly in critical surgical stress;and c) decreasing cellular polyamines not only inhibits HuR-binding to occludin mRNA but also induces cytoplasmic levels of the translational repressor TIAR. Based on these observations, we HYPOTHESIZE that 1) RBPs HuR and TIAR play an important role in the regulation of the intestinal epithelial barrier function by modulating the stability and translation of TJ mRNAs in critical surgical conditions and 2) cellular polyamines regulate occludin translation by altering HuR and TIAR activities.
Three specific aims are proposed to test the hypotheses: 1) to determine the roles of HuR and TIAR in TJ expression and barrier dysfunction during critical surgical stress by using tissue-specific genetic modification strategy;2) to define the exact roles of HuR and TIAR in the posttranscriptional regulation of TJ protein expression;and 3) to investigate the mechanism by which polyamines regulate occludin translation during surgical stress. Completion of these specific aims will provide novel information regarding the posttranscriptional regulation of TJs and also yield a novel model in which occludin translation is regulated by polyamines during surgical stress. It is hoped that our findings will identify factors and mechanisms that can be used to protect the epithelial barrier in patients with critical surgical illnesses.

Public Health Relevance

Increased gut permeability occurs commonly during various critical surgical disorders such as trauma, thermal injury, shock, sepsis, and massive surgical operations, leading to the translocation of luminal toxic substances and bacteria to the blood stream. Since the exact mechanism underlying this acute epithelial barrier dysfunction remains obscure, effective therapies to preserve the integrity of the barrier are limited, contributing to death in critically surgical patients with leaky gut. Completion of this project will identify the pathogenesis of the barrier dysfunction in critical surgical conditions and provide a fundamental base for development of new therapies to protect the gut barrier in patients with critical surgical illnesses.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK068491-09
Application #
8519986
Study Section
Special Emphasis Panel (ZRG1-SBIB-E (02))
Program Officer
Grey, Michael J
Project Start
2004-08-25
Project End
2014-07-31
Budget Start
2013-08-01
Budget End
2014-07-31
Support Year
9
Fiscal Year
2013
Total Cost
$264,991
Indirect Cost
$49,679
Name
University of Maryland Baltimore
Department
Surgery
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Zou, Tongtong; Jaladanki, Suraj K; Liu, Lan et al. (2016) H19 Long Noncoding RNA Regulates Intestinal Epithelial Barrier Function via MicroRNA 675 by Interacting with RNA-Binding Protein HuR. Mol Cell Biol 36:1332-41
Hansraj, Natasha Z; Xiao, Lan; Wu, Jing et al. (2016) Posttranscriptional regulation of 14-3-3ζ by RNA-binding protein HuR modulating intestinal epithelial restitution after wounding. Physiol Rep 4:
Wang, Jun-Yao; Xiao, Lan; Wang, Jian-Ying (2016) Posttranscriptional regulation of intestinal epithelial integrity by noncoding RNAs. Wiley Interdiscip Rev RNA :
Gu, Hui; Yu, Jingwen; Dong, Daoyin et al. (2016) High Glucose-Repressed CITED2 Expression Through miR-200b Triggers the Unfolded Protein Response and Endoplasmic Reticulum Stress. Diabetes 65:149-63
Byrnes, Kimberly A; Phatak, Pornima; Mansour, Daniel et al. (2016) Overexpression of miR-199a-5p decreases esophageal cancer cell proliferation through repression of mitogen-activated protein kinase kinase kinase-11 (MAP3K11). Oncotarget 7:8756-70
Xiao, Lan; Rao, Jaladanki N; Cao, Shan et al. (2016) Long noncoding RNA SPRY4-IT1 regulates intestinal epithelial barrier function by modulating the expression levels of tight junction proteins. Mol Biol Cell 27:617-26
Li, Yanwu; Chen, Gang; Wang, Jun-Yao et al. (2016) Post-transcriptional regulation of Wnt co-receptor LRP6 and RNA-binding protein HuR by miR-29b in intestinal epithelial cells. Biochem J 473:1641-9
Phatak, P; Byrnes, K A; Mansour, D et al. (2016) Overexpression of miR-214-3p in esophageal squamous cancer cells enhances sensitivity to cisplatin by targeting survivin directly and indirectly through CUG-BP1. Oncogene 35:2087-97
Chung, Hee Kyoung; Chen, Yu; Rao, Jaladanki N et al. (2015) Transgenic Expression of miR-222 Disrupts Intestinal Epithelial Regeneration by Targeting Multiple Genes Including Frizzled-7. Mol Med :
Ouyang, Miao; Su, Weijie; Xiao, Lan et al. (2015) Modulation by miR-29b of intestinal epithelium homoeostasis through the repression of menin translation. Biochem J 465:315-23

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