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The neuropeptides α-MSH and NPY modulate phagocytosis and phagolysosome activation in RAW 264.7 cells

Toan A Phan1, Andrew W Taylor

  • 1Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA.

Journal of Neuroimmunology
|May 22, 2013
PubMed

Insights

Neuropeptides alpha-melanocyte stimulating hormone (α-MSH) and neuropeptide Y (NPY) suppress macrophage phagocytosis of unopsonized bacteria. This immune modulation in the eye prevents inflammatory responses.

Area of Science:

  • Immunology
  • Ophthalmology
  • Neuroendocrinology

Background:

  • The ocular microenvironment is immunosuppressive.
  • Immunomodulating neuropeptides, alpha-melanocyte stimulating hormone (α-MSH) and neuropeptide Y (NPY), are present in the eye.
  • These neuropeptides promote suppressor functionality in macrophages.

Purpose of the Study:

  • To investigate the effect of α-MSH and NPY on macrophage phagocytic activity.
  • To determine if these neuropeptides modulate the uptake of bacteria by macrophages.

Main Methods:

  • Macrophages were treated with α-MSH and NPY.
  • Phagocytosis assays were performed using unopsonized and antibody-opsonized Escherichia coli and Staphylococcus aureus bioparticles.
  • Phagolysosome activation and FcR-associated reactive oxidative species generation were measured.

Main Results:

  • α-MSH and NPY significantly suppressed the phagocytosis of unopsonized bacteria.
  • Phagocytosis of antibody-opsonized bioparticles was not affected.
  • Neuropeptide treatment suppressed phagolysosome activation and FcR-associated reactive oxidative species generation.

Conclusions:

  • α-MSH and NPY modulate macrophage phagocytic activity in the ocular microenvironment.
  • This suppression contributes to the regulation of immune responses within the eye.
  • Neuropeptides play a role in preventing immunogenic inflammation in the eye.

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