Date on Master's Thesis/Doctoral Dissertation

8-2014

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Physiology and Biophysics

Committee Chair

Cheadle, William

Committee Member

Bhatnagar, Aruni

Committee Member

D’Souza, Stanley

Committee Member

Maldonado, Claudio

Committee Member

Polk, Hiram C.

Committee Member

Wead, William B.

Subject

Peritonitis; Small interfering RNA

Abstract

This project investigated the role of miRNA-21 in the macrophage response to peritonitis; with the goal of understanding whether the associated mechanism has potential benefits in the clinical treatment of peritonitis. A novel therapeutic intervention in the treatment of peritonitis could modulate the host immune response to decrease an exaggerated pro-inflammatory innate response and then prevent or ameliorate the development of sepsis and organ failure. We found the following: 1. MiRNA-21 expression increases in peritoneal macrophages after lipopolysaccharide (LPS) stimulation. 2. Over expression of miRNA-21 decreases TNF-a secretion from macrophages after LPS stimulation. Suppression of miRNA-21 expression results in increased TNF-a and IL-6, together with decreased IL-10 after LPS stimulation. 3. Protein targets of miRNA-21 after LPS stimulation were not significantly different following suppression of miRNA-21. 4. NF-?B and ERK signaling was unaffected by suppression of miRNA-21. 5. MiRNA-21 is beneficial in survival following induction of peritonitis with LPS. 6. MiRNA-21 does not affect survival following induction of peritonitis with cecal ligation and puncture. These findings demonstrate that although miRNA-21 is beneficial in modulating the macrophage response to LPS, the effect is buried in the multiple pathways activated after the clinically more relevant model of cecal ligation and puncture. The improved understanding of the anti-inflammatory effects of miRNA-21 in the macrophage response to peritonitis may result in a targeted therapy to intervene in clinical peritonitis.

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