Abstract
SOCS3 is the main inhibitor of the JAK/STAT3 pathway. This pathway is activated by interleukin 6 (IL-6), a major mediator of the cytokine storm during shock. To determine its role in the vascular response to shock, we challenged mice lacking SOCS3 in the adult endothelium (SOCS3iEKO) with a nonlethal dose of lipopolysaccharide (LPS). SOCS3iEKO mice died 16–24 hours postinjection after severe kidney failure. Loss of SOCS3 led to an LPS-induced type I IFN–like program and high expression of prothrombotic and proadhesive genes. Consistently, we observed intraluminal leukocyte adhesion and neutrophil extracellular trap–osis (NETosis), as well as retinal venular leukoembolization. Notably, heterozygous mice displayed an intermediate phenotype, suggesting a gene dose effect. In vitro studies were performed to study the role of SOCS3 protein levels in the regulation of the inflammatory response. In human umbilical vein endothelial cells, pulse-chase experiments showed that SOCS3 protein had a half-life less than 20 minutes. Inhibition of SOCS3 ubiquitination and proteasomal degradation led to protein accumulation and a stronger inhibition of IL-6 signaling and barrier function loss. Together, our data demonstrate that the regulation of SOCS3 protein levels is critical to inhibit IL-6–mediated endotheliopathy during shock and provide a promising therapeutic avenue to prevent multiorgan dysfunction through stabilization of endothelial SOCS3.
Highlights
Systemic inflammatory response syndrome [1] often leads to multiorgan dysfunction (MODS) through an acute release of cytokines, in a process often called cytokine storm [2]
interleukin 6 (IL-6) binds to a heterodimeric receptor consisting of a transmembrane glycoprotein 130 subunit that is responsible for signal transduction and a smaller IL-6 receptor α (IL-6Rα), or gp80 subunit, that presents the cytokine to gp130 [9, 15]
Quantitative reverse-transcription PCR (RT-qPCR) of CD45+ cells obtained from spleen (Supplemental Figure 1; supplemental material available online with this article; https://doi.org/10.1172/ jci.insight.147280DS1) demonstrates a lack of SOCS3 excision in these cells (Figure 1C), suggesting a low activity of this Cre driver in hematopoietic cells, a finding that is consistent with other reports [31]
Summary
Systemic inflammatory response syndrome [1] often leads to multiorgan dysfunction (MODS) through an acute release of cytokines, in a process often called cytokine storm [2]. Surviving SOCS3iEKO mice 16 hours postchallenge showed severe kidney failure, accumulation of intraluminal leukocytes in multiple organs, vascular leakage, and a prothrombotic and an adhesive transcriptional response that was associated with a strong induction of type I IFN–regulated genes.
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