Seeing the trees in the forest: selective electroporation of adipocytes within adipose tissue

Electroporation has been recently adapted for the transfer of macromolecules into cells of tissues in vivo. Although mature adipocytes constitute 99% selectivity over other cells in the tissue. Further experiments used the 'adiporation' technique to image the subcellular targeting of fluorescent bioreporter molecules to the nucleus, mitochondria, and lipid droplets of adipocytes within intact adipose tissue. Finally, we utilized fluorescent bioreporters to examine the effects of constitutive activation of the [beta]-adrenergic signaling pathway in adipocytes. These results demonstrate that overexpression of rat [[beta].sub.1]wadrenergic receptors alters the cellular morphology of white adipocytes in a fashion that mimics the effects of systemic infusion of [[beta].sub.3]-adrenergic receptor agonists. Hallmarks of the altered morphology include pronounced fragmentation of the single lipid droplet, repositioning of the nucleus, and induction of mitochondrial biogenesis. These results indicate that activation of [beta]-adrenergic signaling within adipocytes is sufficient to induce a phenotype that resembles typical brown adipocytes and suggest that in vivo electroporation will allow molecular dissection of the mechanisms involved. lipid droplet; morphology; perilipin; subcellular targeting; plasticity; mitochondrial biogenesis; gene transfer; biological imaging