Date of Award

2010

Degree Type

Dissertation

Department

Biological, Geological and Environmental Sciences

First Advisor

Fox, Paul L.

Subject Headings

Ceruloplasmin, Colitis, Ceruloplasmin, DSS-induced colitis, Aceruloplasminemia

Abstract

Ceruloplasmin (Cp) is an acute phase, plasma protein with multiple enzymatic activities consistent with both pro- and anti-inflammatory functions. Our laboratory has recently reported the presence of Cp in intestinal epithelial cells. To determine the potential role of Cp in intestinal inflammation, we induced colitis in Cp-deficient mice by continuous administration of dextran sodium sulfate (DSS) ad libitum in the drinking water. The Cp-null mice rapidly lost weight and all were moribund by day 14, while about 90 of the wild-type (WT) mice survived at least 20 days. Higher amounts of TNF-alpha, and neutrophil (KC) and macrophage (MCP-1) chemokines, were detected in colon culture supernatants in Cp-null mice compared to WT controls. Cp-null mice also exhibited excessive colonic bleeding after 5 days, which correlated with elevated white blood cells, neutrophils, and lymphocytes in the blood, and higher histopathology. Depletion of commensal microflora by antibiotic treatment demonstrated that excessive inflammation in Cp-null animals is microbiota-independent. Interestingly, microbiota-depleted Cp-null animals appear to have higher epithelial damage caused by DSS since they become moribund about 10 days earlier than WT controls. We have investigated the protective mechanism of Cp by injection of Cp into knockout mice. Unexpectedly, mimicking Cp secretion by liver and restoring blood Cp did not lessen the severity of inflammation. This finding was supported by the transplantation of Cp-null bone marrow (BM) into WT controls and vice versa 90 of WT animals with Cp-null BM became moribund by day 14, whereas most of the KO mice with WT BM survived until day 20 of DSS administration. Since macrophages are the only source known to express Cp, we transferred WT macrophages to Cp-null animals all of which survived continuous DSS challenge. Our results demonstrate that Cp derived from macrophages contributes to the protection against DSS-induced damage and colonic inflammation

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