Myeloid CCR2 Promotes Atherosclerosis after AKI

Abstract

Visual Abstract

Background 

The risk of cardiovascular events rises after AKI. Leukocytes promote atherosclerotic plaque growth and instability. We established a model of enhanced remote atherosclerosis after renal ischemia-reperfusion (IR) injury and investigated the underlying inflammatory mechanisms.

Methods 

Atherosclerotic lesions and inflammation were investigated in native and bone marrow–transplanted LDL receptor–deficient (LDLr^−/−) mice after unilateral renal IR injury using histology, flow cytometry, and gene expression analysis.

Results 

Aortic root atherosclerotic lesions were significantly larger after renal IR injury than in controls. A gene expression screen revealed enrichment for chemokines and their cognate receptors in aortas of IR-injured mice in early atherosclerosis, and of T cell–associated genes in advanced disease. Confocal microscopy revealed increased aortic macrophage proximity to T cells. Differential aortic inflammatory gene regulation in IR-injured mice largely paralleled the pattern in the injured kidney. Single-cell analysis identified renal cell types that produced soluble mediators upregulated in the atherosclerotic aorta. The analysis revealed a marked early increase in Ccl2, which CCR2⁺ myeloid cells mainly expressed. CCR2 mediated myeloid cell homing to the post-ischemic kidney in a cell-individual manner. Reconstitution with Ccr2^−/− bone marrow dampened renal post-ischemic inflammation, reduced aortic Ccl2 and inflammatory macrophage marker CD11c, and abrogated excess aortic atherosclerotic plaque formation after renal IR.

Conclusions 

Our data introduce an experimental model of remote proatherogenic effects of renal IR and delineate myeloid CCR2 signaling as a mechanistic requirement. Monocytes should be considered as mobile mediators when addressing systemic vascular sequelae of kidney injury.