Logo image
Loss of interleukin-21 receptor activation in hypoxic endothelial cells impairs perfusion recovery after hindlimb ischemia
Journal article   Open access   Peer reviewed

Loss of interleukin-21 receptor activation in hypoxic endothelial cells impairs perfusion recovery after hindlimb ischemia

Tao Wang, Alexis Cunningham, Ayotunde O Dokun, Surovi Hazarika, Kevin Houston, Lingdan Chen, R John Lye, Rosanne Spolski, Warren J Leonard and Brian H Annex
Arteriosclerosis, thrombosis, and vascular biology, Vol.35(5), pp.1218-1225
05/2015
DOI: 10.1161/ATVBAHA.115.305476
PMCID: PMC4865891
PMID: 25838422
url
https://doi.org/10.1161/ATVBAHA.115.305476View
Published (Version of record) Open Access

Abstract

Surgical hindlimb ischemia (HLI) in mice has become a valuable preclinical model to study peripheral arterial disease. We previously identified that the different phenotypic outcomes after HLI across inbred mouse strains is related to a region on the short arm of mouse chromosome 7. The gene coding the interleukin-21 receptor (IL-21R) lies at the peak of association in this region. With quantitative real-time polymerase chain reaction, we found that a mouse strain with a greater ability to upregulate IL-21R after HLI had better perfusion recovery than a strain with no upregulation after HLI. Immunofluorescent staining of ischemic hindlimb tissue showed IL-21R expression on endothelial cells (ECs) from C57BL/6 mice. An EC-enriched fraction isolated from ischemic hindlimb muscle showed higher Il-21R levels than an EC-enriched fraction from nonischemic limbs. In vitro, human umbilical vein ECs showed elevated IL-21R expression after hypoxia and serum starvation. Under these conditions, IL-21 treatment increased cell viability, decreased cell apoptosis, and augmented tube formation. In vivo, either knockout Il21r or blocking IL-21 signaling by treating with IL-21R-Fc (fusion protein that blocks IL-21 binding to its receptor) in C57BL/6 mice resulted in less perfusion recovery after HLI. Both in vitro and in vivo modulation of the IL-21/IL-21R axis under hypoxic conditions resulted in increased signal transducer and activator of transcription 3 phosphorylation and a subsequent increase in the B-cell lymphoma leukemia-2/BCL-2-associated X protein ratio. Our data indicate that IL-21R upregulation and ligand activation in hypoxic ECs may help perfusion recovery by limiting/preventing apoptosis and favoring cell survival and angiogenesis through the signal transducer and activator of transcription 3 pathway.
Signal Transduction Animals Apoptosis - genetics Cell Hypoxia - physiology Cell Survival - genetics Cells, Cultured Disease Models, Animal Endothelial Cells - cytology Endothelial Cells - metabolism Gene Expression Regulation Hindlimb - blood supply Ischemia - genetics Ischemia - pathology Ischemia - physiopathology Mice Mice, Inbred BALB C Mice, Inbred C57BL Random Allocation Real-Time Polymerase Chain Reaction - methods Receptors, Interleukin-21 - genetics Recovery of Function Reperfusion RNA, Messenger - analysis Up-Regulation

Details

Logo image