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Efferocytosis and Genomic Polymorphism in Autoimmune Diseases

NCT00364728 · Status: UNKNOWN · Type: OBSERVATIONAL · Enrollment: 450

Last updated 2010-05-21

No results posted yet for this study

Summary

Over the past few years, growing evidences revealed that clearance of apoptotic cells by phagocytosis can result in powerful anti-inflammatory and immunosuppressive effects. In vivo, apoptotic cells are cleared rapidly by neighboring cells, macrophages and related scavengers. Defective clearance of apoptotic cells has been linked closely to autoimmunity and persistent inflammatory disease. Several phagocytic receptors, bridging molecules produced by phagocytes and 'eat-me' signals on apoptotic cells are coordinately involved in mediating clearance of apoptotic cells. Complement receptors (CR3, CR4), collection, CD14, CD36 (Class B scavenger receptor), class A scavenger receptor, asialoprotein receptor, Mer receptor kinase were reported to recognize apoptotic cells. The best characterized system for clearance of apoptotic cells is the recognition of phosphatidylserine (PS) on apoptotic cells by phosphatidylserine receptor (PSR). Milk fat globule- epidermal growth factor 8 (MFG-E8) is an opsonin that bridges phagocytes (by interacting with α vβ3, αvβ5 integrins via RGD motif) and apoptotic cells (by binding PS through Factor V/VIII-C domain). Activated macrophages produce and secret MFG-E8. MFG-E8 is a critical component in PSR-mediated phagocytosis of apoptotic cells. The dominant negative mutant MFG-E8, D89E, that carried a mutated RGD motif inhibited phagocytosis of apoptotic cells in vitro. Injection of D89E into wild type mice induced autoantibodies and IgG deposition on glomeruli. Macrophages from MFG-E8 deficiency (MFG-E8-/-) mice were impaired in engulfment of apoptotic cells, which can be restored by adding recombinant MFG-E8. The female MFG-E8-/- mice spontaneously produced high titer of autoantibodies and developed lupus-like glomerulonephritis at the age of week 40. Defective clearance of apoptotic cells is closely related to development of autoimmunity. In the past 4 years, a growing number of molecules were recognized as receptors for the PS exposed on the apoptotic cells. These molecules were capable of mediating phagocytic clearance, rendering anti-inflammatory cytokines in the phagocytes, and modulating T cell responses.

The specific aim of this proposal is to study genetic polymorphism in MFG-E8, PSR and other factors implicated in phagocytic clearance of apoptotic cells among Taiwanese. By comparing the polymorphism between patients with autoimmune disease (SLE or RA) and healthy control subjects, we will investigate if genetic variations among individuals of genes encoding proteins involved in clearance of apoptotic cells contribute to the pathogenesis of systemic autoimmune diseases SLE and RA.

Conditions

Sponsors & Collaborators

  • National Taiwan University Hospital

    lead OTHER

Principal Investigators

  • Chung-Yi Hu, PhD · Department of Clinical Laboratory Sciences and Medical Biotechnology

Eligibility

Min Age
20 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2006-01-31
Primary Completion
2012-07-31
Completion
2012-07-31

Countries

  • Taiwan

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00364728 on ClinicalTrials.gov