Stephanie Haase and Xue Xiao Will Present Their Research on Wednesday, 1/14/2015
Exploring Clock Neuron Activity using the ArcLight fluorescent voltage sensor
Molecular clocks control rhythmic fluctuations in behavior, transcription, and physiology on approximately 24 hour cycles. These circadian rhythms persist in the absence of external light cues and are driven by special clock neurons in both Drosophila and mammals. The interactions of these clock neurons as a network are not fully understood. Previously, changes in clock neuron function that affected circadian rhythmicity were studied primarily through behavioral assays. ArcLight is a powerful tool that will allow characterization of changes to clock neuron function at the cellular level. ArcLight, a fluorescent voltage sensing protein, has allowed the use of optical electrophysiology on clock neurons that traditional electrophysiology cannot access. By expressing ArcLight protein in these neurons, we are able to identify a putative daily rhythm of activity for a subset of these neurons. We are currently working on identifying daily rhythms of other clock neurons using ArcLight and plan to characterize behavioral mutants at the cellular level in the future.
Rescuing the Renal Phenotype in Murine Model of C3 Glomerulonephritis by Delivering Soluble CR1Using the PiggyBac Transposon System
C3 glomerulopathy (C3G) encompasses two prototypical diseases, dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). Both diseases are characterized by fluid-phase dysregulation of the alternative pathway (AP) of complement that leads to C3 deposition in the renal glomerulus. Because disease triggers are unknown and specific treatments are lacking, progress to end-stage renal failure is the common final outcome in 50% of patients. Soluble complement receptor 1 (sCR1) is a potent regulator of complement. In short-term studies it is capable of rescuing the renal phenotype in a murine model of C3GN, the Cfh-/-/huCR1-Tg. To determine whether long-term expression of sCR1 could affect renal outcome, we used hydrodynamic tail vein injection and the PiggyBac transposon system to introduce a sCR1 construct into the same mouse model. Injected mice expressed sCR1 (LHR A-C), had elevated circulating C3 and showed arrested glomerular deposition of C3. These data suggest that long-term expression of sCR1 corrects the C3GN phenotype in these animals and may be a viable treatment solution for patients with this disease.