Regulation of glucocorticoid receptor gamma (GRgamma) by glucocorticoid receptor haplotype and glucocorticoid

Ex-vivo expansion of red blood cells: how real for transfusion in humans?

Blood transfusion is indispensable for modern medicine. In developed countries, the blood supply is adequate and safe but blood for alloimmunized patients is often unavailable. Concerns are increasing that donations may become inadequate in the future as the population ages prompting a search for alternative transfusion products. Improvements in culture conditions and proof-of-principle studies in animal models have suggested that ex-vivo expanded red cells may represent such a product. Compared to other cell therapies transfusion poses the unique challenge of requiring great cell doses (2.5×10(12) cells vs 10(7) cells). Although production of such cell numbers is theoretically possible, current technologies generate red cells in numbers sufficient only for safety studies. It is conceived that by the time these studies will be completed, technical barriers to mass cell production will have been eliminated making transfusion with ex-vivo generated red cells a reality.

Glucocorticoids: exemplars of multi-tasking

Well over 80 years ago Philip Smith described the beneficial clinical effects of adrenocortical extracts in animal models of adrenal insufficiency. In the ensuing years, scientists across the globe have sought to understand the mechanisms by which adrenal hormones and their synthetic analogues produce their complex and varied actions. Particular attention has focused on the glucocorticoids, partly because they have a vital place in the treatment of inflammatory and autoimmune disorders but also because dysregulation of the secretion and/or activity of endogenous glucocorticoids is increasingly implicated in a number of common disorders that pose a growing clinical burden, such as obesity, type II diabetes, the metabolic syndrome, hypertension and depression. This review considers some of the key advances that have been made in our understanding of the physiology, pathology and pharmacology of the glucocorticoids. Emphasis is placed on the molecular mechanisms of glucocorticoid signalling and the complex mechanisms that regulate the access of steroids in the systemic circulation to their receptors in their various target cells and tissues. In addition, consideration is given to the irreversible 'organisational' actions of glucocorticoids in perinatal life and to the potential role of the steroids in the aetiology of disease.

Use of gene expression profiling to identify a novel glucocorticoid sensitivity determining gene, BMPRII

Wide variation in glucocorticoid (Gc) sensitivity exists between individuals which may influence susceptibility to, and treatment response of, inflammatory diseases. To determine a genetic fingerprint of Gc sensitivity 100 healthy human volunteers were polarized into the 10% most Gc-sensitive and 10% most Gc-resistant following a low dose dexamethasone (0.25 mg) suppression test. Gene expression profiling of primary lymphocytes identified the 98 most significantly Gc regulated genes. These genes were used to build a subnetwork of Gc signaling, with 54 genes mapping as nodes, and 6 non-Gc regulated genes inferred as signaling nodes. Twenty four of the 98 genes showed a difference in Gc response in vitro dependent on the Gc sensitivity of their donor individuals in vivo. A predictive model was built using both partial least squares discriminate analysis and support vector machines that predicted donor glucocorticoid sensitivity with 87% accuracy. Discriminating genes included bone morphogenetic protein receptor, type II (BMPRII). Transfection studies showed that BMPRII modulated Gc action. These studies reveal a broad base of gene expression that predicts Gc sensitivity and determine a Gc signaling network in human primary T lymphocytes. Furthermore, this combined gene profiling, and functional analysis approach has identified BMPRII as a modulator of Gc signaling.

Glucocorticoid sensitivity: pathology, mutations and clinical implications

Glucocorticoids exert diverse effects on virtually all cell types and tissues. Subtle changes in sensitivity may be generalized and congenital or acquired in a tissue-specific manner. Such changes may lead to altered susceptibility to metabolic diseases, such as ischemic heart disease, or to insensitivity to the therapeutic actions of synthetic glucocorticoids such as in inflammatory disease. This review will cover current theories of how glucocorticoids exert genetic and other congenital effects on glucocorticoid sensitivity, and acquired changes in glucocorticoid sensitivity seen principally in inflammatory and malignant disease. Recent important developments in the field include the impact of genetic variation within the glucocorticoid receptor gene, the effects of early life experience on long-term glucocorticoid sensitivity, studies identifying the role of nuclear factor κB in modulating glucocorticoid sensitivity in vitro and in vivo, and the action of macrophage migration inhibitory factor in modulating the anti-inflammatory effects of glucocorticoids. The role of chromatin organization in regulating glucocorticoid action on proinflammatory genes is discussed, as is the regulation of glucocorticoid sensitivity in human malignancy in the context of pathogenesis and treatment response.