Human P2Y11 Expression Level Affects Human P2X7 Receptor-Mediated Cell Death
Karin Dreisig1, Louise Sund1, Maja Wallentin Dommer1
1Molecular Sleep Laboratory, Department of Clinical Biochemistry, Rigshospitalet, Glostrup Hospital, Glostrup, Denmark.
Abstract:
Adenosine triphosphate (ATP) is known to induce cell death in T lymphocytes at high extracellular concentrations. CD4+ and CD8+ T lymphocytes have a differential response to ATP, which in mice is due to differences in the P2X7 receptor expression levels. By contrast, we observed that the difference in human CD4+ and CD8+ T lymphocyte response toward the synthetic ATP-analog BzATP is not explained by a difference in human P2X7 receptor expression. Rather, the BzATP-induced human P2X7 receptor response in naïve and immune-activated lymphocyte subtypes correlated with the expression of another ATP-binding receptor: the human P2Y11 receptor. In a recombinant expression system, the coexpression of the human P2Y11 receptor counteracted BzATP-induced human P2X7 receptor-driven lactate dehydrogenase release (a marker of cell death) and pore formation independent of calcium signaling. A mutated non-signaling human P2Y11 receptor had a similar human P2X7 receptor-inhibitory effect on pore formation, thus demonstrating that the human P2X7 receptor interference was not caused by human P2Y11 receptor signaling. In conclusion, we demonstrate an important species difference in the ATP-mediated cell death between mice and human cells and show that in human T lymphocytes, the expression of the human P2Y11 receptor correlates with human P2X7 receptor-driven cell death following BzATP stimulation.
Insights
High extracellular adenosine triphosphate (ATP) causes T lymphocyte cell death. In humans, the P2Y11 receptor, not P2X7 receptor expression, influences this ATP-induced cell death, revealing a species-specific mechanism.
Area of Science:
- Immunology
- Cell Biology
- Pharmacology
Background:
- Extracellular adenosine triphosphate (ATP) at high concentrations induces T lymphocyte cell death.
- In mice, differential P2X7 receptor expression explains the varied response of CD4+ and CD8+ T lymphocytes to ATP.
- The mechanism underlying differential T lymphocyte responses to ATP analogs in humans is not fully understood.
Purpose of the Study:
- To investigate the differential response of human CD4+ and CD8+ T lymphocytes to the synthetic ATP analog, BzATP.
- To elucidate the role of P2X7 and P2Y11 receptors in BzATP-induced T lymphocyte cell death in humans.
- To identify species-specific differences in ATP-mediated T lymphocyte cell death mechanisms.
Main Methods:
- Compared human CD4+ and CD8+ T lymphocyte responses to BzATP.
- Assessed P2X7 and P2Y11 receptor expression levels in human lymphocytes.
- Utilized a recombinant expression system to study receptor interactions and BzATP-induced cell death markers (lactate dehydrogenase release, pore formation).
Main Results:
- Human T lymphocyte response to BzATP was not solely dependent on P2X7 receptor expression levels.
- BzATP-induced P2X7 receptor response correlated with P2Y11 receptor expression in human lymphocyte subtypes.
- Co-expression of P2Y11 receptor counteracted BzATP-induced P2X7 receptor-mediated cell death and pore formation, independent of calcium signaling.
Conclusions:
- Significant species differences exist in ATP-mediated T lymphocyte cell death between mice and humans.
- In human T lymphocytes, P2Y11 receptor expression is a key factor correlating with P2X7 receptor-driven cell death following BzATP stimulation.
- P2Y11 receptor's inhibitory effect on P2X7 receptor function is independent of its signaling pathway.
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