LINEAGE CONVERSION OF BLOOD-DERIVED ENDOTHELIAL PROGENITOR CELLS TO AN ADRENOCORTICAL PHENOYPE: A NEW TECHNOLOGY TO STUDY THE ADRENAL GLAND.

点击翻译按钮获取中文摘要

The adrenal glands are part of the endocrine system, which releases hormones into the blood system. Each adrenal gland is anatomically and functionally composed of two distinct parts, an outer cortex and inner medulla. The adrenal cortex is essential for life: it produces glucocorticoids that regulate body metabolism, and mineralocorticoids that affect blood pressure. Adrenal cortex disorders can cause your adrenal glands to produce too much or not enough hormones; some disorders can be determined by genetic mutations. Adrenal studies are usually carried out by using cell lines established from tumors or cell lines transfected with a gene of interest: both systems have several drawbacks such as the inability to produce a full steroid profile or the inherent difficulty to extrapolate physiologically relevant data from an over-expression system. Animal models are also frequently used to investigate the development, function and pathology of adrenal glands, as well as for testing new treatments and for toxicology studies. However some animal models obtained through knockout technology fail to generate the human disease (Triple-A syndrome and NNT dependent-Familial Glucocorticoid Deficiency are two examples in the adrenal field). Cell reprogramming techniques are becoming powerful tools for replacing animal models and procedures as well as for studying the cause of a particular disease and for drug testing. Cellular reprogramming describes the process where a fully differentiated, specialized cell type is induced to transform into a different cell type that it would not otherwise become under normal physiological conditions. Cellular reprogramming has been achieved using a variety of methods, including somatic cell nuclear transfer, cell-cell fusion and, most recently, through the introduction of transcription factors. Two scientists, Sir John Gordon of Britain and Shinya Yamanaka of Japan were awarded the Nobel Prize for the category Physiology and Medicine in 2012 for their groundbreaking discoveries in the field. Gordon's research was conducted in 1962 and showed that it was possible to reverse the specialization of cells. By transferring a nucleus from a frog's intestinal cell into a frog's egg cell that had its nucleus removed, he was able to obtain a tadpole. Building on Gordon's work, Yamanaka published a paper in 2006 demonstrating that mature murine cells can become immature stem cells (called inducible pluripotent stem cells, IPSCs) by expressing genes encoding four transcription factors. IPSCs can be differentiated to several tissues using specific protocols. Yamanaka's breakthrough opened the door to studying disease and developing diagnosis and treatments. Recently, the generation of a cell type from an unrelated cell type without the need of an IPSCs intermediate has been described by using specific cell fate-transcription factors. This process has been named lineage conversion. Regardless of the method used, skin fibroblasts have been a predominant source material so far but an invasive surgical procedure (skin biopsy) is required to establish primary cells, and not always possible. A blood draw would be an ideal starting point to obtain donor-specific cells because it is minimally invasive and established procedures are already in place for acquisition and handling. In fact, scientists have recently employed this patient-friendly way to establish long-term in vitro culture of blood-derived cells, and importantly, they have been able to reprogram efficiently these cells into IPSCs. One of these cell types are late-outgrowth endothelial progenitor cells (L-EPCs).With this proposal, I aim at developing a technology whereby L-EPCs are reprogrammed to acquire an adrenocortical phenotype using lineage conversion, by forcing the expression of single cell fate regulator, Steroidogenic Factor 1.