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Updated: Feb 11, 2026
Screening Assays to Characterize Novel Endothelial Regulators Involved in the Inflammatory Response
Published on: September 15, 2017
RIP kinase 1-dependent endothelial necroptosis underlies systemic inflammatory response syndrome
Matija Zelic1, Justine E Roderick1, Joanne A O'Donnell1
1Department of Molecular, Cell and Cancer Biology, and.
Abstract:
Receptor interacting protein kinase 1 (RIPK1) has important kinase-dependent and kinase-independent scaffolding functions that activate or prevent apoptosis or necroptosis in a cell context-dependent manner. The kinase activity of RIPK1 mediates hypothermia and lethality in a mouse model of TNF-induced shock, reflecting the hyperinflammatory state of systemic inflammatory response syndrome (SIRS), where the proinflammatory "cytokine storm" has long been viewed as detrimental. Here, we demonstrate that cytokine and chemokine levels did not predict survival and, importantly, that kinase-inactive Ripk1D138N/D138N hematopoietic cells afforded little protection from TNF- or TNF/zVAD-induced shock in reconstituted mice. Unexpectedly, RIPK1 kinase-inactive mice transplanted with WT hematopoietic cells remained resistant to TNF-induced shock, revealing that a nonhematopoietic lineage mediated protection. TNF-treated Ripk1D138N/D138N mice exhibited no significant increases in intestinal or vascular permeability, nor did they activate the clotting cascade. We show that TNF administration damaged the liver vascular endothelium and induced phosphorylated mixed lineage kinase domain-like (phospho-MLKL) reactivity in endothelial cells isolated from TNF/zVAD-treated WT, but not Ripk1D138N/D138N, mice. These data reveal that the tissue damage present in this SIRS model is reflected, in part, by breaks in the vasculature due to endothelial cell necroptosis and thereby predict that RIPK1 kinase inhibitors may provide clinical benefit to shock and/or sepsis patients.
Insights
Receptor interacting protein kinase 1 (RIPK1) kinase activity drives shock and lethality. Nonhematopoietic cells, not cytokines, mediate protection, suggesting RIPK1 inhibitors could treat sepsis.
Area of Science:
- Cellular signaling pathways
- Immunology
- Vascular biology
Background:
- Receptor interacting protein kinase 1 (RIPK1) has dual kinase-dependent and -independent roles in cell death pathways like apoptosis and necroptosis.
- TNF-induced shock models systemic inflammatory response syndrome (SIRS), characterized by a detrimental cytokine storm.
- The role of RIPK1 kinase activity in SIRS pathogenesis and potential therapeutic targets remains incompletely understood.
Purpose of the Study:
- To investigate the role of RIPK1 kinase activity in TNF-induced shock.
- To determine whether hematopoietic or nonhematopoietic cells mediate protection from shock.
- To identify the cellular mechanisms underlying tissue damage in this SIRS model.
Main Methods:
- Utilized kinase-inactive Ripk1D138N/D138N mice and wild-type (WT) mice in bone marrow chimeric models.
- Administered TNF or TNF/zVAD to induce shock and assessed survival, cytokine levels, vascular permeability, and clotting cascade activation.
- Examined liver vascular endothelium and endothelial cell necroptosis marker (phospho-MLKL) in response to TNF treatment.
Main Results:
- Kinase-inactive Ripk1D138N/D138N hematopoietic cells provided minimal protection from shock.
- Mice with kinase-inactive Ripk1D138N/D138N nonhematopoietic cells were resistant to TNF-induced shock, indicating a nonhematopoietic protective role.
- TNF-induced shock did not correlate with increased cytokine levels or predict survival.
- Endothelial cell necroptosis in the liver vasculature was observed in WT but not Ripk1D138N/D138N mice, contributing to vascular leakage.
Conclusions:
- RIPK1 kinase activity, rather than cytokine storm, is critical for TNF-induced shock lethality.
- Nonhematopoietic cells, specifically the vascular endothelium, play a key role in mediating resistance to shock.
- Endothelial cell necroptosis contributes to vascular damage in SIRS, positioning RIPK1 kinase inhibitors as potential therapeutics for shock and sepsis.
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