Aims/Introduction: Electronegative low-density lipoprotein (L5) is the most atherogenic fraction of low-density lipoprotein and is elevated in people with metabolic syndrome (MetS), whereas the retinol-binding protein 4 receptor (stimulated by retinoic acid 6 [STRA6]) cascade is disrupted in various organs of patients with obesity-related diseases. Our objective was to investigate whether L5 from MetS patients capably induces pathogenesis of aorta through disrupting the STRA6 cascade. Material and Methods: We examined the in vivo and in vitro effects of L5 on the STRA6 cascade and aortic atherogenic markers. To investigate the role of this cascade on atherosclerotic formation, crbp1 transfection was carried out in vitro.Results: This study shows that L5 activates atherogenic markers (p38 mitogen-activated protein kinases, pSmad2 and matrix metallopeptidase 9) and simultaneously suppresses STRA6 signals (STRA6, cellular retinol-binding protein 1, lecithin-retinol acyltransferase, retinoic acid receptor-a and retinoid X receptor-a) in aortas of L5-injected mice and L5-treated human aortic endothelial cell lines and human aortic smooth muscle cell lines. These L5-induced changes of the STRA6 cascade and atherogenic markers were reversed in aortas of LOX1 -/mice and in LOX1 ribonucleic acid-silenced human aortic endothelial cell lines and human aortic smooth muscle cell lines. Furthermore, crbp1 gene transfection reversed the disruption of the STRA6 cascade, the phosphorylation of p38 mitogen-activated protein kinases and Smad2, and the elevation of matrix metallopeptidase 9 in L5treated human aortic endothelial cell lines. Conclusions: This study shows that L5 from MetS patients induces atherogenic markers by disrupting STRA6 signaling. Suppression of STRA6 might be one novel pathogenesis of aorta in patients with MetS.

In this paper, an alternative algorithm based on subspace rotation invariance techniques is presented for estimating the directions-of-arrival (DOAs) of uncorrelated narrow-band plane waves in noise using the data pencil compressed by the Karhunen–Loève transform (KLT). It is shown that the compressed data pencil preserves the rotation invariance property, and therefore it can be employed by subspace rotation invariance algorithms, e.g., the original ESPRIT, the TLS-ESPRIT, and PRO-ESPRIT, to estimate the DOAs. Due to the reduced-dimension compressed data pencil, the proposed algorithm has a much faster speed in computation than the above ESPRIT algorithms. In addition, computer simulations illustrate that the proposed algorithm exhibits better statistical characteristics than the original ESPRIT and comparable to the PRO-ESPRIT and the TLS-ESPRIT, respectively.

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