Biological Sciences Seminars
Neural and endocrine regulation of nutrient and energy homeostasis
by Dr. Jishy Varghese (nstitute of Molecular and Cell Biology, Singapore)
Monday, October 29, 2012
from
to
(Asia/Kolkata)
at Colaba Campus ( B-333 )
at Colaba Campus ( B-333 )
Description |
Living organisms need energy for functions like growth, locomotion, defense and reproduction. In multi-cellular animals built-in homeostatic mechanisms control nutrient intake according to energy needs and regulate energy requiring processes according to nutrient availability. Break down of energy and nutrient balance is responsible for metabolic disorders like diabetes and obesity which affects ~0.5 billion people globally according to current estimates. However, exact reasons of why the homeostatic mechanisms fail leading to these diseases are still not clear. Past few decades of research show that neural and endocrine centers play a key role in maintaining nutrient and energy homeostasis. But intricate nature and complex distribution of these regulatory centers has precluded a complete understanding of the mechanisms involved. To investigate the regulatory mechanisms of energy homeostasis I use genetic model organism Drosophila with less complex neural and endocrine systems. The conserved insulin-signaling pathway maintains nutrient homeostasis by sensing and regulating nutrient levels available for energy production. Over the past few years evidence has begun to accumulate that insulin production and secretion as well as cellular responsiveness to insulin are subject to regulation by microRNAs. I will present evidence from my recent paper that Drosophila microRNA miR-14 acts in the insulin producing neurosecretory cells in the adult brain to control fat metabolism. miR-14 allows the fly to manage resource mobilization in a nutritionally variable environment by regulating insulin gene expression. I will also present on going work on a novel mechanism of nutrient sensing and homeostatic maintenance that involves the highly conserved hypoxia-signaling pathway. I will show evidence that metabolic intermediates play a direct role in this process. Further, I will discuss my future plans to investigate mechanisms of nutrient sensing and maintenance of energy homeostasis by the neural and endocrine centers using Drosophila and mammalian model systems. |