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Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

SIGN-R1, a C-type lectin, enhances apoptotic cell clearance through the complement deposition pathway by interacting

M G Prabagar1, Y Do, S Ryu

  • 1Department of Biomedical Science and Technology, SMART Institute of Advanced Biomedical Science, Institute of Functional Genomics, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.

Cell Death and Differentiation
|December 15, 2012
PubMed

Insights

SIGN-R1 initiates apoptotic cell clearance by binding to C1q and mediating C3 deposition in the spleen. This process is crucial for systemic immune tolerance and preventing autoimmunity.

Area of Science:

  • Immunology
  • Cell Biology

Background:

  • Marginal zone macrophages (MZMs) and complement proteins (C1q, C3) are vital for clearing apoptotic cells.
  • SIGN-R1, a C-type lectin on MZMs, interacts with C1q to combat Streptococcus pneumoniae.

Purpose of the Study:

  • To investigate the role of the SIGN-R1-mediated classical complement pathway in apoptotic cell clearance and immune tolerance.

Main Methods:

  • Studied the binding of SIGN-R1 to apoptotic cells with and without C1q.
  • Analyzed C3 deposition on apoptotic cells in wild-type and SIGN-R1 knockout mice.
  • Assessed cytokine secretion and autoantibody levels in response to SIGN-R1 deficiency.

Main Results:

  • SIGN-R1 directly binds apoptotic cells, enhanced by C1q, leading to C3 deposition and clearance.
  • SIGN-R1 deficiency abolished splenic C3 deposition and delayed apoptotic cell clearance.
  • SIGN-R1 deficiency resulted in aberrant cytokine secretion and increased anti-DNA antibody levels.

Conclusions:

  • SIGN-R1 initiates a novel mechanism for systemic apoptotic cell clearance via complement activation.
  • SIGN-R1 integrates apoptotic cell recognition, complement opsonization, and immune tolerance induction.

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