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Selective adenosine release from human B but not T lymphoid cell line
J Barankiewicz1, G Ronlov, R Jimenez
1Gensia Pharmaceuticals, Inc., San Diego, California 92121.
The Journal of Biological Chemistry
|September 15, 1990
Summary
B lymphoblasts release significant adenosine when ATP is degraded, unlike T lymphoblasts. This difference in adenosine release is due to distinct enzyme activities in B and T cells.
Area of Science:
- Cell Biology
- Biochemistry
- Immunology
Background:
- Adenosine plays a crucial role in cellular signaling and metabolism.
- Understanding adenosine formation and release is vital for studying cellular stress responses.
- Lymphoblasts, as immune cells, have unique metabolic pathways that warrant investigation.
Purpose of the Study:
- To investigate and compare intracellular adenosine formation and extracellular release in B lymphoblasts (WI-L2-B) and T lymphoblasts (SupT1-T).
- To elucidate the enzymatic basis for differential adenosine release between B and T lymphoblasts under conditions of ATP catabolism.
- To determine the role of specific enzymes, including adenosine deaminase and adenosine kinase, in regulating adenosine levels.
Main Methods:
- Studied adenosine metabolism in WI-L2-B and SupT1-T lymphoblasts under induced and non-induced ATP catabolism.
- Assessed the impact of adenosine deaminase and adenosine kinase inhibitors on adenosine release.
- Compared the activities of key enzymes involved in adenosine metabolism (AMP deaminase, AMP-5'-nucleotidase, adenosine kinase, adenosine deaminase) between B and T lymphoblasts.
Main Results:
- B lymphoblasts released significant adenosine under induced ATP catabolism, which was further elevated by adenosine deaminase inhibitors.
- T lymphoblasts released minimal adenosine, even with combined inhibition of adenosine deaminase and adenosine kinase.
- Differential enzyme activities were observed: B lymphoblasts have high AMP-5'-nucleotidase and low adenosine kinase/deaminase, favoring adenosine release.
- T lymphoblasts possess low AMP-5'-nucleotidase and high adenosine kinase/deaminase, efficiently utilizing or degrading adenosine, thus limiting release.
Conclusions:
- B lymphoblasts are identified as significant adenosine producers due to a specific enzyme profile favoring adenosine release.
- T lymphoblasts exhibit an enzyme combination that prevents substantial adenosine production and release, even under stress.
- Cellular adenosine production capacity is cell-type specific, influenced by the balance of enzymes regulating its synthesis and utilization.