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P2Z adenosine triphosphate receptor activity in cultured human monocyte-derived macrophages
S E Hickman1, J el Khoury, S Greenberg
1Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, New York, NY 10032.
Abstract:
The present study shows that human mononuclear phagocytes express a P2Z-like purinergic membrane receptor activity. Extracellular adenosine triphosphate (ATP) induces the formation of nonselective membrane pores in human mononuclear phagocytes that allow the entry of otherwise membrane impermeant fluorescent dyes (YO-PRO-1 or Lucifer yellow) into the cytoplasm of these cells. The percentage of mononuclear phagocytes that was permeabilized by ATP increased as monocytes matured into macrophages. Their response to ATP was inhibited by Mg2+ and oxidized ATP. Benzoylbenzoic-ATP (BzBzATP) was approximately 60% as effective as ATP and adenosine-5 -O-(thiophosphate) (ATP gamma S) was less than 20% as effective as ATP in permeabilizing human macrophages to YO-PRO-1 or Lucifer Yellow. Thus, the human P2Z-like receptor differs from its murine counterpart because BzBzATP, ATP, and ATP gamma S are equally efficacious in permeabilizing murine macrophage-like J774 cells to these dyes. UTP, GTP, and CTP were ineffective in permeabilizing human or murine macrophages to YO-PRO-1. Taken together, these data indicate that human monocyte-derived macrophages express a P2Z-like activity that is pharmacologically distinct from that expressed by their murine counterparts and that expression of these receptors is developmentally regulated in human mononuclear phagocytes.
Insights
Human mononuclear phagocytes have a P2Z-like receptor. Extracellular adenosine triphosphate (ATP) creates pores, allowing dye entry, with increased activity in macrophages and distinct properties from mouse cells.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Mononuclear phagocytes play crucial roles in immunity and inflammation.
- Purinergic signaling via P2 receptors is involved in various cellular processes.
- Understanding purinergic receptor subtypes and their functions is essential for therapeutic development.
Purpose of the Study:
- To investigate the presence and characteristics of P2Z-like purinergic receptor activity in human mononuclear phagocytes.
- To compare the pharmacological properties of human P2Z-like receptors with their murine counterparts.
- To examine the developmental regulation of P2Z-like receptor expression during monocyte-to-macrophage differentiation.
Main Methods:
- Human mononuclear phagocytes (monocytes and macrophages) were utilized.
- Extracellular adenosine triphosphate (ATP) was used to induce membrane permeabilization.
- Fluorescent dyes (YO-PRO-1, Lucifer yellow) were employed to assess membrane integrity.
- Pharmacological agents including Mg2+, oxidized ATP, Benzoylbenzoic-ATP (BzBzATP), and adenosine-5 -O-(thiophosphate) (ATPγS) were used to characterize receptor activity.
- Murine macrophage-like J774 cells were used for comparative studies.
Main Results:
- Human mononuclear phagocytes express a P2Z-like purinergic receptor activity.
- Extracellular ATP induced nonselective membrane pore formation, allowing dye entry.
- ATP-induced permeabilization increased with monocyte maturation into macrophages.
- Receptor activity was inhibited by Mg2+ and oxidized ATP.
- BzBzATP and ATPγS showed differential efficacy in human macrophages compared to ATP, unlike in murine J774 cells.
- UTP, GTP, and CTP were ineffective in permeabilizing either human or murine macrophages.
Conclusions:
- Human monocyte-derived macrophages express a P2Z-like purinergic receptor activity.
- This human receptor exhibits distinct pharmacological properties compared to the murine P2Z receptor.
- The expression of these P2Z-like receptors is developmentally regulated during human mononuclear phagocyte differentiation.