Project Summary Many pharmacotherapies capitalize on the powerful control of the autonomic nervous system (ANS) over peripheral organ functions, but unintended side effects of drugs are often an important issue. Therefore, more function-specific activation of autonomic outflow would be a welcome addition to the therapeutic repertoire for many conditions and diseases. Here we propose to apply the modern tool box of neuron-specific manipulation such as optogenetic and pharmacogenetic stimulation and inhibition to the ANS. This technology is based on neurotrophic viral vectors carrying instructions for transfecting excitatory or inhibitory ion channels or receptors into specific neuron populations and has been widely used in the CNS of rodents. Because the technology has not yet been used in the ANS, we will test the feasibility of different viruses and viral constructs to selectively transfect sympathetic (SNS) neurons innervating adipose tissue as a model system (Aim 1) and use genetically based technology to generate a gene profile of adipose tissue related SNS neurons that are verified in human tissue. This should result in i) viral constructs with proven ability to selectively and efficiently infect/transfect postganglionic SNS neurons, ii) maps of chemo-specific postganglionic SNS neurons innervating brown and white adipose tissue in the mouse, and iii) maps of detailed innervation patterns of adipose tissue pads for future selective denervation and electrical stimulation approaches, iv) genetic profile of adipose tissue related SNS neurons and their representation in human SNS neurons. In Aim 2, we will test the ability of acute and chronic optogenetic and pharmacogenetic stimulation of successfully transfected postganglionic SNS neurons innervating brown adipose tissue to induce thermogenesis, energy expenditure, and body weight loss and SNS neurons innervating subcutaneous white adipose tissue to induce lipolysis and browning. We will thus provide proof-of-principle for genetically-based functionally specific ANS manipulation that could be applied to any other postganglionic autonomic neuron, such as the noradrenergic innervation of hepatocytes and pancreatic islets, as well as cholinergic (vagal) innervation of myenteric plexus neurons throughout the gastrointestinal tract, pancreatic islets, the biliary system, and the liver. This will ultimately allow selective manipulation of other aspects of energy balance and glucose homeostasis as well as cardiovascular, respiratory, urogenital, and gastrointestinal functions in a modular fashion.