title: In vivocharacterization of genetic expression of virus-transduced calcium indicators in retinal ganglion cells using a low-cost funduscope.
abstract: Virus-transduced calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. To track the level ofin vivoexpression of genetically encoded calcium indicators (GECIs) in rodent retina, we developed a noninvasive imaging approach based on a custom-modified low-cost and simple fundus system that enabled us to monitor and characterizein vivobright-field and fluorescence retinal image. The system clearly resolves individual retinal ganglion cells (RGCs) and axons. RGC fluorescence intensity and number of observable fluorescent cells show a consistent rising trend from week 1 to week 3 after viral injection, indicating a uniform increase of GCaMP6f expression. At defined time points, we prepared wholemount retina mounted on a transparent multielectrode array (MEA) and used calcium imaging to identify the optimal time for studying the responsiveness of RGCs to external electrical stimulation. The results show that the fluorescence-endoscopy fundus system is a powerful and widely accessible tool for evaluatingin vivofluorescence reporter expression.
authors.affiliation: University of Southern California, Los Angeles, ca 90033, USA.
authors.forename: Yao-Chuan
authors.initials: YC
authors.lastname: Chang
authors.affiliation: University of Southern California, Los Angeles, ca 90033, USA.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Walston
authors.affiliation: University of Southern California, Los Angeles, ca 90033, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Chow
authors.affiliation: University of Southern California, Los Angeles, ca 90033, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Weiland
mesh_terms: D001369:Axons; D002118:Calcium; D019721:Ophthalmoscopes; D012160:Retina; D012165:Retinal Ganglion Cells
chemical_list: D002118:Calcium