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| February 28,2006 | Smad transcription factors | ||||||||
| Smad transcription factors lie at the core of one of the most versatile cytokine signaling pathways in metazoan biology—the transforming growth factor-β(TGFβ) pathway. Recent progress has shed light into the processes of Smad activation and deactivation, nucleocytoplasmic dynamics, and assembly of transcriptional complexes. A rich repertoire of regulatory devices exerts control over each step of the Smad pathway. This knowledge is enabling work on more complex questions about the organization, integration, and modulation of Smad-dependent transcriptional programs. We are beginning to uncover self-enabled gene response cascades, graded Smad response mechanisms, and Smad-dependent synexpression groups. Our growing understanding of TGFβ signaling through the Smad pathway provides general principles for how animal cells translate complex inputs into concrete behavior. | |||||||||
| February 27,2006 | Sudden cardiac death: mechanisms, therapies and challenges | ||||||||
| Sudden cardiac death (SCD) is the leading cause of cardiac death in the US. In the past few years, intensive efforts have been made to expand public awareness of SCD and to increase our understanding of its pathophysiology, medical treatment options and device therapy. Significant advances have been made in our ability to prevent SCD in both primary and secondary health care. Two critical issues remain, however: the identification of patients who would benefit from such therapies, and how to achieve even greater prevention, especially primary prevention. The goal of this article is to provide a review of the topic of SCD in the setting of abnormal myocardial substrate, to outline the techniques that are useful in identifying patients at risk, and available treatment options. | |||||||||
| February 26,2006 | Activation of the mammalian immune system by siRNAs | ||||||||
| Inhibition of gene expression through RNA interference(RNAi)is emerging as a powerful experimental tool for geng function and target validation studies.The potential uses of this technology seem unlimited,extending to the prevention and therapy of human diseaes.However,recent work demonstrating that are unanticipated,different nonspecific effects associated with the use of small interfering RNAs in mammals has raised concerns about the safe use of RNAs in vivo.These nonspecific effects include activation of the immune system,potentially harming the individual. The application of screening assays for nonspecific activation of both innate and acquired immunity will be necessary for further development of RNAi an a therapeutic tool. | |||||||||
| February 25,2006 | Cerebrovascular gene linked to Alzheimer’s disease pathology | ||||||||
| There is already considerable evidence from epidemiological, pathological and clinical reports that vascular factors are crucial in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion has been shown to be a preclinical condition and a most accurate indicator for predicting whether people will develop AD. Now, a new study by Zlokovic and colleagues reveals that the vascular gene MEOX2 has a low expression in cultured brain endothelial cells from AD patients. This, together with evidence linking a dysfunctional cerebrovasculature to the pathogenesis of AD, suggests that the homeobox gene MEOX2 downregulation provides a therapeutic target to AD and a better understanding of this disorder. | |||||||||
| February 24,2006 | Helper T cells and atherosclerosis | ||||||||
| There is growing evidence regarding the importance of inflammation in the pathogenesis of atherosclerosis and its ultimate progression to the clinical syndromes. Recently there has been an increasing interest in the role of helper T (Th) cells in atherosclerosis. The Th cells act with the macrophages and the dendritic cells via the various cytokines in bringing about a variety of changes thus leading to the progression of atherosclerosis. Atherosclerotic lesions have been seen to have increased expression of type 1 helper T (TH1) cells together with increased levels of the Th1 related cytokines. It is mainly the cytokines involved with Th1 functioning that seem to show a prominent effect, with the whole process centred around interferon gamma, making it seem like every pathway and the cytokines involved lead to a final common pathway of interferon gamma secretion; the increase or decrease of which dictates the progression of atherosclerosis and its final manifestation as the clinical syndromes. | |||||||||
| February 23,2006 | Surrogate markers for atherosclerotic disease | ||||||||
| Novel treatment modalities for cardiovascular prevention are emerging rapidly. Since it is virtually impossible to evaluate all these new compounds in long-term trials using clinical end points, there is an urgent need for validated surrogate markers of atherosclerosis to save both time and costs. Over the last decade, the use of imaging markers has been widely introduced into drug-development strategies. Here we will discuss the most commonly used techniques. | |||||||||
| February 22,2006 | Drug-conjugated monoclonal antibodies for the treatment of cancer | ||||||||
| Early clinical development in the field of targeted delivery of cytotoxic drugs to tumors was not successful because the limitations imposed by the pharmacokinetic and pharmacodynamic properties of monoclonal antibodies were not fully appreciated. Recently, development of this concept has been reinvigorated by the approval of gemtuzumab ozogamicin for treatment of acute myeloid leukemia. Other conjugates of calicheamicin and conjugates of potent tubulin poisons (maytansinoids auristatins and taxoids) are undergoing clinical evaluation or are in preclinical development. What all of these drugs have in common is that their cytotoxic potencies are in the picomolar range. Thirty years after the discovery of monoclonal antibodies, this new generation of highly potent compounds could yield targeted cytotoxic agents that are effective treatments for many cancers. | |||||||||
| February 21,2006 | A candidate gene approach to searching for low-penetrance breast and prostate cancer genes | ||||||||
| Most cases of breast and prostate cancer are not associated with mutations in known high-penetrance genes, indicating the involvement of multiple lowpenetrance risk alleles. Studies that have attempted to identify these genes have met with limited success. The National Cancer Institute Breast and Prostate Cancer Cohort Consortium — a pooled analysis of multiple large cohort studies with a total of more than 5,000 cases of breast cancer and 8,000 cases of prostate cancer — was therefore initiated. The goal of this consortium is to characterize variations in approximately 50 genes that mediate two pathways that are associated with these cancers — the steroid-hormone metabolism pathway and the insulin-like growth factor signalling pathway — and to associate these variations with cancer risk. | |||||||||
| February 20,2006 | Quest for Novel Cardiovascular Biomarkers by Proteomic Analysis | ||||||||
| Atherosclerosis, and the resulting coronary heart disease and stroke, is the most common cause of death in developed countries. Atherosclerosis is an inflammatory process that results in the development of complex lesions or plaques that protrude into the arterial lumen. Plaque rupture and thrombosis result in the acute clinical complications of myocardial infarction (MI) and stroke. Although certain risk factors (dyslipidemias, diabetes, hypertension) and humoral markers of plaque vulnerability (C-reactive protein, interleukin-6, 10 and 18, CD40L) have been identified, a highly sensitive and specific biomarker or protein profile, which could provide information on the stability/vulnerability of atherosclerotic lesions, remains to be identified. | |||||||||
| February 19,2006 | Chronic heart failure | ||||||||
| Chronic heart failure (CHF) is a leading cause of hospitalization and is associated with a poor prognosis, although in the past decade substantial progress has been made in understanding the pathophysiology and therapy of CHF with reduced left ventricular (LV) ejection fraction. Use of angiotensinconverting- enzyme inhibitors and angiotensin-receptor antagonists either individually or in combination, certain β-receptor blockers, and judicious use of aldosterone antagonists, has reduced hospital admission rates and mortality from CHF with reduced LV ejection fraction. More clinical trials are needed, however, particularly in patients with CHF and preserved LV ejection fraction. | |||||||||
| February 18,2006 | macrophage-derived foam cells emerging as therapeutic targets in atherosclerosis | ||||||||
| The limited efficacy of current treatment strategies for targeting atherosclerosis and its complications requires new therapeutic options to be explored. From early fatty-streak lesions to advanced plaques, macrophage-derived foam cells are integral to the development and progression of atherosclerosis. Elucidation of molecular and cellular processes involving macrophages has led to numerous therapeutic targets being suggested. Potential sites of intervention range from monocyte recruitment, through cholesterol uptake and esterification, to cholesterol evacuation and macrophage egress from plaque. In addition, complex patterns of transcriptional regulation of genes involved in macrophage lipid homeostasis and in the regulation of inflammation have been partly unraveled. | |||||||||
| February 17,2006 | The molecular pathogenesis of acute myeloid leukemia | ||||||||
| The description of the molecular pathogenesis of acute myeloid leukemias (AML) has seen dramatic progress over the last years. Two major types of genetic events have been described that are crucial for leukemic transformation: alterations in myeloid transcription factors governing hematopoietic differentiation and activating mutations of signal transduction intermediates. These processes are highly interdependent, since the molecular events changing the transcriptional control in hematopoietic progenitor cells modify the composition of signal transduction molecules available for growth factor receptors, while the activating mutations in signal transduction molecules induce alterations in the activity and expression of several transcription factors that are crucial for normal myeloid differentiation. The purpose of this article is to review the current literature describing these genetic events, their biological consequences and their clinical implications. | |||||||||
| February 16,2006 | Immunomodulation of atherosclerosis with a vaccine | ||||||||
| Experimental observations have established that the innate and adaptive immune mechanisms both have roles in the modulation of atherosclerosis. The complex function that the immune system has in the pathophysiology of atherosclerosis is highlighted by the fact that both proatherogenic and atheroprotective effects of immune activation can be demonstrated. An immune response to the protein and lipid components of oxidized LDL cholesterol has been observed in experimental models, and immunization with these antigens has generally reduced atherosclerosis. The findings suggest the tantalizing possibility that an atheroprotective vaccine can be developed. | |||||||||
| February 15,2006 | Reconstruction of genetic circuits | ||||||||
| The complex genetic circuits found in cells are ordinarily studied by analysis of genetic and biochemical perturbations. The inherent modularity of biological components like genes and proteins enables a complementary approach: one can construct and analyse synthetic genetic circuits based on their natural counterparts. Such synthetic circuits can be used as simple in vivo models to explore the relation between the structure and function of a genetic circuit. Here we describe recent progress in this area of synthetic biology, highlighting newly developed genetic components and biological lessons learned from this approach. | |||||||||
| February 14,2006 | Nanotechnology for drug and gene therapy | ||||||||
| Nanotechnology, although not a new concept, has gained significant momentum in recent years. This stems partly from the realization that nanosystems have significantly different biological properties from large-sized systems (e.g. implants or microparticles) that could be used effectively to overcome problems in drug and gene therapy. In drug therapy, we face the problems of inefficacy or nonspecific effects; hence, nanosystems are being developed for targeted drug therapy. In gene therapy using non-viral systems, the main issues are relatively transient gene expression and lower efficiency than viral vectors. Research efforts have focused on understanding the barriers in gene delivery so that non-viral systems can be developed that are as effective as viral systems in gene transfection. | |||||||||
| February 13,2006 | macrophage-derived foam cells emerging as therapeutic targets in atherosclerosis | ||||||||
| The limited efficacy of current treatment strategies for targeting atherosclerosis and its complications requires new therapeutic options to be explored. From early fatty-streak lesions to advanced plaques, macrophage-derived foam cells are integral to the development and progression of atherosclerosis. Elucidation of molecular and cellular processes involving macrophages has led to numerous therapeutic targets being suggested. Potential sites of intervention range from monocyte recruitment, through cholesterol uptake and esterification, to cholesterol evacuation and macrophage egress from plaque. In addition, complex patterns of transcriptional regulation of genes involved in macrophage lipid homeostasis and in the regulation of inflammation have been partly unraveled. | |||||||||
| February 12,2006 | Mechanisms of Disease: inflammation and the origins of cancer | ||||||||
| Many common cancers develop as a consequence of years of chronic inflammation. Increasing evidence indicates that the inflammation may result from persistent mucosal or epithelial cell colonization by microorganisms; including hepatitis B virus and hepatitis C virus, which can cause hepatocellular cancer; human papilloma virus subtypes, which cause cervical cancer, and the bacterium Helicobacter pylori, which can cause gastric cancer. At present, the cause of other chronic inflammatory conditions associated with increased cancer risk, such as ulcerative colitis, is obscure. Particular microbial characteristics as well as the type of the inflammatory response contribute to clinical outcomes via influence on epithelial cell and immune responses. | |||||||||
| February 11,2006 | Crosstalk in G protein-coupled receptors | ||||||||
| Functional crosstalk between G protein-coupled receptors in a homo- or heterodimeric assembly likely involves conformational changes at the dimer interface, but the nature of this interface is not yet established, and the dynamic changes have not yet been identified. We have mapped the homodimer interface in the dopamine D2 receptor over the entire length of the fourth transmembrane segment (TM4) by crosslinking of substituted cysteines. Their susceptibilities to crosslinking are differentially altered by the presence of agonists and inverse agonists. The TM4 dimer interface in the inverse agonist-bound conformation is consistent with the dimer of the inactive form of rhodopsin modeled with constraints from atomic force microscopy. | |||||||||
| February 10,2006 | Preserving cardiac function in the hypertensive patient | ||||||||
| The relationship between cardiovascular and renal pathologies is well recognized in advanced nephropathy and heart failure, but in early disease it has received less attention. Consequently, microalbuminuria screening and interventions that treat early nephropathy remain under-utilized cardioprotective strategies in the hypertensive patient. Agents that delay the progression of renal disease are likely to be cardioprotective by lessening the systemic consequences of renal dysfunction and may have additional cardioprotective effects by exerting beneficial effects on endothelia elsewhere in the body and within the heart. A critical driving factor within both renal and wider cardiovascular pathologies is overactivation of the renin–angiotensin–aldosterone system (RAAS). | |||||||||
| February 9,2006 | Genetic polymorphisms and multifactorial diseases: facts and fallacies revealed by the glucocorticoid receptor gene | ||||||||
| In recent years enormous progress in determining the sequence of the human genome has led to a rapid development of research into polymorphisms in genes involved in complex diseases. It is clear, however, that there are important limitations in many of these association studies. Problems with reliable and reproducable phenotyping, the number of individuals studied, racial heterogeneity, population stratification (founder effect), functionality and multiple testing often mean that studies are not reproducible. In this review we describe a number of the limitations related to this type of research; from both our own experience with studies on polymorphisms in the glucocorticoid receptor gene, and shortcomings and solutions from the literature. | |||||||||
| February 8,2006 | Adeno-associated virus vectors: potential applications for cancer gene therapy | ||||||||
| Augmenting cancer treatment by protein and gene delivery continues to gain momentum based on success in animal models. The primary hurdle of fully exploiting the arsenal of molecular targets and therapeutic transgenes continues to be efficient delivery. Vectors based on adeno-associated virus (AAV) are of particular interest as they are capable of inducing transgene expression in a broad range of tissues for a relatively long time without stimulation of a cell-mediated immune response. Perhaps the most important attribute of AAV vectors is their safety profile in phase I clinical trials ranging from CF to Parkinson’s disease. The utility of AAV vectors as a gene delivery agent in cancer therapy is showing promise in preclinical studies. In this review, we will focus on the basic biology of AAV as well as recent progress in the use of this vector in cancer gene therapy. | |||||||||
| February 7,2006 | Epicardial adipose tissue: anatomic, biomolecular and clinical relationships with the heart | ||||||||
| A growing amount of evidence suggests that regional fat distribution plays an important part in the development of an unfavorable metabolic and cardiovascular risk profile. Epicardial fat is a metabolically active organ that generates various bioactive molecules, which might significantly affect cardiac function. This small, visceral fat depot is now recognized as a rich source of free fatty acids and a number of bioactive molecules, such as adiponectin, resistin and inflammatory cytokines, which could affect the coronary artery response. The observed increases in concentrations of inflammatory factors in patients who have undergone coronary artery bypass grafting remain to be confirmed in healthy individuals. Furthermore, epicardial adipose mass might reflect intra-abdominal visceral fat. Therefore, we propose that echocardiographic assessment of this tissue could serve as a reliable marker of visceral adiposity. Epicardial adipose tissue is also clinically related to left ventricular mass and other features f the metabolic syndrome, such as concentrations of LDL cholesterol, fasting insulin and adiponectin, and arterial blood pressure. Echocardiographic assessment of epicardial fat could be a simple and practical tool for cardiovascular risk stratification in clinical practice and research. In this paper, we briefly review the rapidly emerging evidence pointing to a specific role of epicardial adipose tissue both as a cardiac risk marker and as a potentially active player in the development of cardiac pathology. | |||||||||
| February 6,2006 | Silence of the transcripts: RNA interference in medicine | ||||||||
| Silencing of gene expression by ribonucleic acid (RNA), known as RNA interference (RNAi), is now recognized as a major means of gene regulation in biology. In this mechanism, small noncoding double-stranded RNA molecules knock down gene expression through a variety of mechanisms that include messenger RNA (mRNA) degradation, inhibition of mRNA translation, or chromatin remodeling. The posttranscriptional mechanism of RNAi has been embraced by researchers as a powerful tool for generating deficient phenotypes without mutating the gene. In parallel, exciting recent results have promised its application in disease therapy. This review aims to summarize the current knowledge in this area and provide a roadmap that may eventually launch RNAi from the research bench to the medicine chest. | |||||||||
| February 5,2006 | THE CELL BIOLOGY OF NEUROGENESIS | ||||||||
| During the development of the mammalian central nervous system, neural stem cells and their derivative progenitor cells generate neurons by asymmetric and symmetric divisions. The proliferation versus differentiation of these cells and the type of division are closely linked to their epithelial characteristics, notably, their apical–basal polarity and cell-cycle length. Here, we discuss how these features change during development from neuroepithelial to radial glial cells, and how this transition affects cell fate and neurogenesis. | |||||||||
| February 4,2006 | THERAPEUTICS DEVELOPMENT FOR TRIPLET REPEAT EXPANSION DISEASES | ||||||||
| The underlying genetic mutations for many inherited neurodegenerative disorders have been identified in recent years. One frequent type of mutation is trinucleotide repeat expansion. Depending on the location of the repeat expansion, the mutation might result in a loss of function of the disease gene, a toxic gain of function or both. Disease gene identification has led to the development of model systems for investigating disease mechanisms and evaluating treatments. Examination of experimental findings reveals similarities in disease mechanisms as well as possibilities for treatment. | |||||||||
| February 3,2006 | Investigation of the Mouse Serum Proteome | ||||||||
| With the rapid assimilation of genomic information and the equally impressive developments in the field of proteomics, there is an unprecedented interest in biomarker discovery. Although human biofluids represent increasingly attractive samples from which new and more accurate disease biomarkers may be found, the intrinsic person-to-person variability in these samples complicates their discovery. One of the most extensively used animal models for studying human disease is mouse because, unlike humans, they represent a highly controllable experimental model system. Unfortunately, very little is known about the proteomic composition of mouse serum. In this study, a multidimensional fractionation approach on both the protein and the peptide level that does not require depletion of highly abundant serum proteins was combined with tandem mass spectrometry to characterize proteins within mouse serum. Over 12 300 unique peptides that originate from 4567 unique proteinssapproximately 16% of all known mouse proteinssw e identified. The results presented here represent the broadest proteome coverage in mouse serum and provide a foundation from which quantitative comparisons can be made in this important animal model. | |||||||||
| February 2,2006 | The Akt of translational control | ||||||||
| The oncogene AKT (also called protein kinase B (PKB)) signals to the translational machinery, and activation of protein synthesis by Akt is associated with cancer formation. Akt directly stimulates the activity of translation initiation factors and upregulates ribosome biogenesis. Activation of protein synthesis by Akt is phylogenetically conserved from Drosophila to humans, and is important for regulating cell growth, proliferation and cell survival. Consequently, translation defects due to aberrant Akt activation may be a crucial mechanism leading to tumorigenesis. However, few in vivo studies have established a causative role for aberrant protein synthesis control in cancer. A major challenge in the future will be to identify the speci?c mRNAs regulated at the level of translation control directly relevant for cellular transformation. In this review, we highlight and discuss the emerging molecular and genetic evidence that support a model by which deregulation of speci?c or global protein synthesis contributes to cancer. | |||||||||
| February 1,2006 | EXPLOITING THE PI3K/AKT PATHWAY FOR CANCER DRUG DISCOVERY | ||||||||
| Evolving studies with several different targeted therapeutic agents are demonstrating that patients with genomic alterations of the target, including amplification, translocation and mutation, are more likely to respond to the therapy. Recent studies indicate that numerous components of the phosphatidylinositol-3-kinase (PI3K)/AKT pathway are targeted by amplification, mutation and translocation more frequently than any other pathway in cancer patients, with resultant activation of the pathway. This warrants exploiting the PI3K/AKT pathway for cancer drug discovery. |
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