Abstract-Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), encoded by the OLR1 gene, is a scavenger receptor that plays a fundamental role in the pathogenesis of atherosclerosis. LOX-1 activation is associated with apoptosis of endothelial cells, smooth muscle cells (SMCs), and macrophages. This process is an important underlying mechanism that contributes to plaque instability and subsequent development of acute coronary syndromes. Independent association genetic studies have implicated OLR1 gene variants in myocardial infarction (MI) susceptibility. Because single nucleotide polymorphisms (SNPs) linked to MI are located in intronic sequences of the gene, it remains unclear as to how they determine their biological effects. Using quantitative real-time PCR and minigene approach, we show that intronic SNPs, linked to MI, regulate the expression of a new functional splicing isoform of the OLR1 gene, LOXIN, which lacks exon 5. Macrophages from subjects carrying the "non-risk" disease haplotype at OLR1 gene have an increased expression of LOXIN at mRNA and protein level, which results in a significant reduction of apoptosis in response to oxLDL. Expression of LOXIN in different cell types results in loss of surface staining, indicating that truncation of the C-terminal portion of the protein has a profound effect on its cellular trafficking. Furthermore, the proapoptotic effect of LOX-1 receptor in cell culture is specifically rescued by the coexpression of LOXIN in a dose-dependent manner. The demonstration that increasing levels of LOXIN protect cells from LOX-1 induced apoptosis sets a groundwork for developing therapeutic approaches for prevention of plaque instability.
Systemic signs of inflammation, similar to those found in atherosclerosis, are present in patients with degenerative aortic valve stenosis. They do not seem to be linked to C. pneumoniae or H. pylori infection.
The role of p16(INK4A) as a marker of HR-HPV and in the diagnosis of CIN has been well established, but its predictive value in the clearance of the virus after CIN treatment and its use as a prognostic marker of cervical cancer has not been studied. A series of 302 archival samples, including 150 squamous cell carcinomas (SCCs) and 152 CIN lesions, were subjected to immunohistochemical staining for p16(INK4A) and HPV testing using PCR with three primer sets (MY09/11, GP5/GP6, SPF). Follow-up data were available of 88 SCC patients, and 67 of the CIN lesions had been followed-up with serial PCR after conization. HR-HPV types were closely associated with CIN (OR 19.12; 95%CI 2.31-157.81) and SCC (OR 27.25; 95%CI 3.28-226.09). There was a significant linear relationship between the lesion grade and intensity of p16(INK4A) staining (p = 0.0001). The expression of p16(INK4A) was also closely related to HR-HPV (p = 0.0001). p16(INK4A) staining was a 100% specific indicator of CIN, with 100% PPV, and showed 83.5% sensitivity and 80.1% PPV in detecting HR-HPV. However, p16(INK4A) staining did not predict clearance/persistence of HR-HPV after treatment of CIN. Similarly, despite a slightly more favorable survival in women with strong/intense p16(INK4A) staining in univariate analysis, p16(INK4A) expression was not an independent prognostic predictor in multivariate survival (Cox) analysis. After adjustment for p16(INK4A) staining, HR-HPV, histological grade, International Federation of Gynecology and Obstetrics (FIGO) stage, and age, only the last two were significant prognostic predictors (p = 0.0001 and p = 0.003, respectively). The present data confirm the role of p16(INK4A) as a highly specific marker of CIN and HR-HPV type, but expression of this protein does not seem to be of any prognostic value in cervical cancer or in predicting the clearance of HR-HPV after treatment of CIN. We speculate that different subgroups of cervical cancer are characterized by aberrant p16(INK4A)/cyclin D/Rb pathways that are due to different mechanisms that can be mutually exclusive.
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