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The transforming growth factor, TGF-beta(1), has been found to be increased in the central nervous system of Alzheimer's disease (AD) patients, elevates amyloid precursor protein (APP) mRNA levels in rat primary astrocytes, and may initiate or promote the deposition of amyloid-beta (Abeta) peptide in AD. Excess APP production in AD, which potentially leads to amyloidogenesis, is in part due to over expression of APP mRNA. The production of APP in a normal human cell line in contrast to transformed or animal cells provides a meaningful model to study the regulation of APP gene expression by cytokines that promotes amyloidogenesis. Here, we report that TGF-beta(1) treatment of human astrocytes markedly elevated APP mRNA levels, and also increased the half-life of APP message by at least five-fold. Under this condition, as detected by mobility shift and UV cross-linking analysis, a novel 68 kDa RNA-protein complex was formed, involving an 81 nucleotide (nt) fragment within the 3'-untranslated region (UTR), but not the 5'-UTR and coding region of APP mRNA. Insertion of the 3'-UTR onto the chloramphenicol acetyl transferase (CAT) mRNA conferred TGF-beta(1) mediated mRNA stability in transfected human astrocytes. On the other hand, the same insert carrying a deletion of the APP mRNA cis-element fragment had no effect on CAT mRNA stability. A model of APP mRNA regulation is presented in which TGF-beta(1) induced stabilization of APP message involves the binding activity of a 68 kDa RNA-protein complex within the 3'-UTR, which is likely linked to a reduction in the rate of APP mRNA decay.

Osteopontin (OPN) is a secreted phosphoprotein involved in cellular proliferation and associated with tumor progression. Although an intracellular form of OPN has been described, its function remains unknown. In this study, a novel nuclear location for intracellular OPN and a correlation with cell division were demonstrated. OPN distinctly localized to the nucleus in a subset of transiently transfected human embryonic kidney 293 cells. Immunoblotting confirmed the nuclear location of native OPN, and results from immunofluorescence studies suggested an association between nuclear OPN and cell cycle progression. Flow cytometry revealed that nuclear and cellular OPN content rose significantly during the S and G2/M phases, respectively. Treatment of cells with the DNA polymerase inhibitor aphidicolin prevented cell cycling and greatly reduced cellular OPN content. The intracellular location of OPN coincided with polo-like kinase-1 (Plk-1), a member of the polo-like kinase family, which, in part through their regulation of centrosome-related events, are integral to successful cellular mitosis. OPN and Plk-1 were coimmunoprecipitated from nuclear, but not cystoslic, extracts, demonstrating an interaction that is limited to the nucleus, presumably during mitosis. Deletion of the COOH terminus of OPN militated against nuclear localization and Plk-1 interaction. Elevated expression of OPN was also associated with an increase in the number of multinucleate 293 cells, whereas transfection of the COOH-terminal-deleted OPN decreased the percentage of multinucleate cells below basal levels. These findings implicate intranuclear OPN as a participant in the process of cell duplication.

This Consensus Conference has been supported by the Canadian Cardiovascular Society. The process is dynamic, with intentional structure that requires peer review and feedback from cardiovascular specialists across Canada. The writing and review panel encompassed a broad range of specialists caring for the patient with peripheral arterial disease (PAD). PAD is an often asymptomatic, underdiagnosed, under-recognized and undertreated condition. It is associated with significant morbidity and cardiac mortality. Until recently, little attention has focused on the evaluation and treatment of the disease process itself. The goal of the present paper is to ensure better treatment, to reduce both morbidity and mortality in the patient with vascular disease and, importantly, to serve as a guide to the busy clinician. Although the focus is PAD, there are chapters on thoracic and abdominal aortic disease, renal arterial disease and the evidence supporting management. Screening and diagnostic techniques including history and physical examination as well as noninvasive imaging techniques are reviewed. Medical management for patients with vascular disease including prevention and risk reduction is graded based on evidence, including both pharmacological and nonpharmacological management strategies, followed by an introduction to newer percutaneous techniques. Finally, surgical treatment for claudication including new concepts on the perioperative risk assessment for patients undergoing major vascular surgery is discussed.