Effects of hedgehog signalling on pancreas development

摘要

During vertebrate embryogenesis, tissues and signalling pathways interact to regulate cell differentiation and morphogenesis of complex organ structures. Communication between mesoderm and endoderm-derived tissues is required for development of the pancreas, a vital organ involved in food digestion and glucose homeostasis. Cells in the exocrine pancreas secrete enzymes into the gut lumen while endocrine cells produce hormones, including insulin and glucagon, that participate in blood glucose regulation. Pancreas organogenesis can be divided into three main phases: initiation, morphogenesis and maturation. During initiation the endodermal sheet that will give rise to the mature endocrine and exocrine pancreatic cell types is in close contact with the meso-dermally derived notochord, a known source of inducing molecules. The first morphogenetic sign of pancreas development is a dorsal evagination of the foregut endoderm posterior to the stomach anlage. Shortly afterwards ventral buds form on the opposite site close to the liver diverticulum. When gut and stomach rotate the ventral bud moves around to the dorsal side where it comes in close contact with the dorsal anlage to form the mature organ. By studying pancreas development we seek to understand the general principles of organogenesis to explain and prevent formation of pancreatic diseases, including pancreatic cancer and diabetes mellitus.