Related Experiment Videos
TNF receptors TR60 and TR80 can mediate apoptosis via induction of distinct signal pathways
M Grell1, G Zimmermann, D Hülser
1Institute of Cell Biology and Immunology, University of Stuttgart, Germany.
Abstract:
TNF membrane receptors are usually co-expressed in many tissues but their relative contribution to cellular TNF responses is for most situations unknown. In a TNF cytotoxicity model of KYM-1, a human rhabdomyosarcoma cell line, we recently demonstrated that each of the two TNFRs is on its own capable of inducing cell death. Here we show that both receptors are able to induce apoptosis, as revealed from a similar onset of DNA fragmentation and typical morphologic criteria. To obtain additional information about the signaling pathways involved in TR60- and TR80-induced programmed cell death, we have used a series of selective inhibitors of intracellular signaling molecules. The overall pattern emerging from these experiments provides strong evidence for distinct signal pathway usage of TR60 and TR80, indicating protein kinase(s)-mediated control of TR60 signaling and a tight linkage of TR80 to arachidonate metabolism. The subsequent establishment of KYM-1-derived cell lines that display TNFR selective resistance further supports a segregation of TR60 and TR80 signaling pathways for induction of apoptotic cell death. Moreover, these results demonstrate an independent control of the distinct signaling cascades used by TR60 and TR80. This allows a highly flexible regulation of a cellular TNF response in those cases in which both receptors contribute to overall TNF responsiveness.
Insights
Tumor Necrosis Factor (TNF) receptors TR60 and TR80 independently trigger apoptosis through distinct signaling pathways. This research clarifies how these TNF membrane receptors regulate cellular responses and programmed cell death.
Area of Science:
- Cellular Biology
- Immunology
- Molecular Biology
Background:
- Tumor Necrosis Factor (TNF) membrane receptors are often co-expressed, but their individual roles in cellular responses are not fully understood.
- Previous studies showed that both TNF receptor types (TNFRs) can induce cell death individually in a human rhabdomyosarcoma cell line (KYM-1).
Purpose of the Study:
- To investigate the distinct intracellular signaling pathways utilized by TR60 and TR80 in mediating TNF-induced apoptosis.
- To understand the independent regulation of these signaling cascades for flexible control of cellular TNF responses.
Main Methods:
- Utilized a TNF cytotoxicity model with KYM-1 cells.
- Employed selective inhibitors targeting intracellular signaling molecules to dissect pathway usage.
- Established KYM-1-derived cell lines with selective resistance to TNFRs to confirm pathway segregation.
Main Results:
- Both TR60 and TR80 were confirmed to induce apoptosis, evidenced by DNA fragmentation and morphological changes.
- Distinct signaling pathways were identified: TR60 signaling is mediated by protein kinases, while TR80 signaling is linked to arachidonate metabolism.
- KYM-1 cell lines with TNFR-selective resistance supported the segregation of TR60 and TR80 signaling pathways for apoptosis induction.
Conclusions:
- TR60 and TR80 activate distinct and independently controlled signaling cascades to induce programmed cell death.
- This independent signaling allows for flexible regulation of cellular TNF responses when both receptors contribute to the overall responsiveness.