Regulation of insulin signaling and its developmental and functional roles on peptidergic neurons in the Drosophila central nervous system
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
In Drosophila, eight insulin-like peptides (DILP1-8) are produced and secreted in different locations. They regulate many aspects of development and physiology, such as organism growth, metabolic homeostasis, reproduction, stress resistance and life span. DILP2, 3 and 5 are mainly produced by a cluster of median neurosecretory cells in the brain known as insulin producing cells (IPCs). Here we showed that IPCs are under tight regulation of two G-protein coupled receptors (GPCRs), serotonin receptor 5-HT1A and octopamine receptor OAMB. Genetic manipulations of these two receptors in IPCs affected transcription levels of DILPs, hence altered feeding, carbohydrate levels, and resistance to stress (Paper I and II). Moreover, we showed that the insulin receptor (dInR) is strongly expressed in leucokininergic neurons (LK neurons), and selectively regulates growth of around 300 neuropeptidergic neurons expressing the bHLH transcription factor DIMMED. Overexpression of dInR in DIMM-positive neurons led to substantial neuronal growth, including cell body size, golgi apparatus and nuclear size, while knockdown of dInR had the opposite effect (Paper III). Manipulations of components in the insulin signaling pathway in LK neurons resulted in the similar cell size phenotypes. Furthermore, dInR regulated size scaling of DIMM-postive neurons is nutrient-dependent and partially requires the presence of DIMM (Paper III). Finally, we investigated the roles of DILPs (2, 3, 5 and 7) and LK neurons in regulation of feeding and diuresis at the adult stage (Paper IV). In summary, we have identified two more regulators for IPC activity and demonstrated developmental roles of DILPs and dInR in regulating neuronal size. Moreover, DILPs regulate water homeostasis together with a diuretic hormone leucokinin and as a consequence affects feeding behavior.
Place, publisher, year, edition, pages
Stockholm: Department of Zoology, Stockholm University , 2013. , 40 p.
Insulin, serotonin, octopamine, insulin receptor, Dimm, neuropeptide
Research subject Functional Zoomorphology
IdentifiersURN: urn:nbn:se:su:diva-96050ISBN: 978-91-7447-817-4OAI: oai:DiVA.org:su-96050DiVA: diva2:662924
2013-12-13, William-Olssonsalen, Geovetenskapens hus, Svante Arrheniusvägen 14, Stockholm, 13:00 (English)
Broughton, Susan, Lecturer Dr.
Nässel, Dick, Professor
FunderSwedish Research Council
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: In press. Paper 4: Manuscript.2013-11-212013-11-082016-01-04Bibliographically approved
List of papers