Abstract
PurposeCav1.4 is a voltage-gated calcium channel clustered at the presynaptic active zones of photoreceptors. Cav1.4 functions in communication by mediating the Ca2+ influx that triggers neurotransmitter release. It also aids in development since rod ribbon synapses do not form in Cav1.4 knock-out mice. Here we used a rescue strategy to investigate the ability of Cav1.4 to trigger synaptogenesis in both immature and mature mouse rods.MethodsIn vivo electroporation was used to transiently express Cav α1F or tamoxifen-inducible Cav α1F in a subset of Cav1.4 knock-out mouse rods. Synaptogenesis was assayed using morphologic markers and a vision-guided water maze.ResultsWe found that introduction of Cav α1F to knock-out terminals rescued synaptic development as indicated by PSD-95 expression and elongated ribbons. When expression of Cav α1F was induced in mature animals, we again found restoration of PSD-95 and elongated ribbons. However, the induced expression of Cav α1F led to diffuse distribution of Cav α1F in the terminal instead of being clustered beneath the ribbon. Approximately a quarter of treated animals passed the water maze test, suggesting the rescue of retinal signaling in these mice.ConclusionsThese data confirm that Cav α1F expression is necessary for rod synaptic terminal development and demonstrate that rescue is robust even in adult animals with late stages of synaptic disease. The degree of rod synaptic plasticity seen here should be sufficient to support future vision-restoring treatments such as gene or cell replacement that will require photoreceptor synaptic rewiring.
Highlights
Cav1.4 is a voltage-gated calcium channel clustered at the presynaptic active zones of photoreceptors
These data confirm that Cav a1F expression is necessary for rod synaptic terminal development and demonstrate that rescue is robust even in adult animals with late stages of synaptic disease
Gene therapy will not be the cure for all forms of I nherited retinal diseases (IRDs); for example, those that cause very rapid and early onset neurodegeneration may not have sufficient living cells remaining by the time a gene therapy vector is available
Summary
In vivo electroporation was used to transiently express Cav a1F or tamoxifeninducible Cav a1F in a subset of Cav1.4 knock-out mouse rods. Synaptogenesis was assayed using morphologic markers and a vision-guided water maze. C57BL/6J (RRID:IMSR_JAX:000664) were used as wildtype (WT) controls, and the Cav1.4 KO mice (RRID:IMSR_JAX:017761) have been previously described.[34]. Mice of both sexes, up to the age of 6 months were used. Mice were housed in a central vivarium, maintained on a standard 12/12-hour light/dark cycle, with food and water provided ad libitum in accordance with the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All procedures adhered to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research and were approved by the University of Iowa IACUC committee.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
