Regulation of Cytokine Production by Macrophages

Studies in Dr. Ignatowski’s laboratory are designed to investigate the bidirectional communication between the nervous and immune systems as it relates to the control of depressive behavior, chronic pain, and inflammation. She uses a combination of in vitro cell culture systems, in vivo electrical field stimulation of brain tissue, molecular methods, immunohistochemical and immunofluorescence staining, and behavioral models to address the question of how brain-derived tumor necrosis factor (TNF), a pro-inflammatory cytokine and neuromediator, functions as a modulator of brain-body interactions during neuropathic pain and in the mechanism of action of antidepressant drugs. Additionally, studies involve investigation of neurotransmitter (adrenergic and cholinergic) regulation of TNF production from the peripheral macrophage, a major source of TNF during inflammation.

Ongoing projects:

1. Study the effects of various neurotransmitters on the release of the cytokine TNF produced by macrophages, immune effector cells. Receptors on macrophages will be stimulated to assess regulation of TNF production during models of neuropathic pain and depression. Macrophage will be harvested from animals at the time of termination, and TNF production will be compared amongst the various animal groups.
2. Use immunohistochemical and immunofluorescence staining to determine whether there is a correlation between levels of TNF in rodents induced with neuropathy and the amount of neurogenesis (growth and development of neurons). We will also compare staining to samples taken from rats administered drugs that are known to alleviate pain behavior and improve depressive behavior in animals. The brains will be harvested and the hippocampi isolated. The brain tissue will be sectioned and specific antibodies will be used to stain for TNF and markers expressed by newly born immature neurons and newly dividing cells.
3. Assess inflammatory mediators, such as high-mobility group box chromosomal protein 1 (HMGB1) produced by macrophages and damaged neurons, from animals with neuropathic pain (diabetic neuropathy, chemotherapy-induced neuropathy) and control animals (rats/mice). We will determine whether animals receiving treatment for neuropathic pain have modified levels of inflammatory mediators.

It is anticipated that at the end of the project, students will have generated data for a poster presentation (at the minimum).

• Lab Safety Training
• Read papers from the lab
  • "Regulation of macrophage-derived tumor necrosis factor production by modification of adrenergic receptor sensitivity" in the Journal of Neuroimmunology
  • "The hippocampus and TNF: Common links between chronic pain and depression" in Neuroscience and Biobehavioral Reviews

Pathology and Anatomical Sciences