Abnormal High-Density Lipoprotein Induces Endothelial Dysfunction via Activation of Toll-like Receptor-2

SummaryEndothelial injury and dysfunction (ED) represent a link between cardiovascular risk factors promoting hypertension and atherosclerosis, the leading cause of death in Western populations. High-density lipoprotein (HDL) is considered antiatherogenic and known to prevent ED. Using HDL from children and adults with chronic kidney dysfunction (HDLCKD), a population with high cardiovascular risk, we have demonstrated that HDLCKD in contrast to HDLHealthy promoted endothelial superoxide production, substantially reduced nitric oxide (NO) bioavailability, and subsequently increased arterial blood pressure (ABP). We have identified symmetric dimethylarginine (SDMA) in HDLCKD that causes transformation from physiological HDL into an abnormal lipoprotein inducing ED. Furthermore, we report that HDLCKD reduced endothelial NO availability via toll-like receptor-2 (TLR-2), leading to impaired endothelial repair, increased proinflammatory activation, and ABP. These data demonstrate how SDMA can modify the HDL particle to mimic a damage-associated molecular pattern that activates TLR-2 via a TLR-1- or TLR-6-coreceptor-independent pathway, linking abnormal HDL to innate immunity, ED, and hypertension.

Graphical AbstractFigure optionsDownload high-quality image (608 K)Download as PowerPoint slideHighlights
► HDLCKD inhibits endothelial NO and increases oxidant stress and inflammation via TLR-2
► TLR-2 deficiency prevents increased arterial blood pressure in response to HDLCKD
► HDL-SDMA mediates adverse endothelial effects of HDLCKD by TLR-2 activation
► HDLCKD activates TLR2 via a TLR-1- or TLR-6-coreceptor-independent pathway