R-type calcium channels are crucial for semaphorin 3A-induced DRG axon growth cone collapse

PLoS One. 2014 Jul 17;9(7):e102357. doi: 10.1371/journal.pone.0102357. eCollection 2014.

Abstract

Semaphorin 3A (Sema3A) is a secreted protein involved in axon path-finding during nervous system development. Calcium signaling plays an important role during axonal growth in response to different guidance cues; however it remains unclear whether this is also the case for Sema3A. In this study we used intracellular calcium imaging to figure out whether Sema3A-induced growth cone collapse is a Ca2+ dependent process. Intracellular Ca2+ imaging results using Fura-2 AM showed Ca2+ increase in E15 mice dorsal root ganglia neurons upon Sema3A treatment. Consequently we analyzed Sema3A effect on growth cones after blocking or modifying intracellular and extracellular Ca2+ channels that are expressed in E15 mouse embryos. Our results demonstrate that Sema3A increased growth cone collapse rate is blocked by the non-selective R- and T- type Ca2+ channel blocker NiCl2 and by the selective R-type Ca2+ channel blocker SNX482. These Ca2+ channel blockers consistently decreased the Sema3A-induced intracellular Ca2+ concentration elevation. Overall, our results demonstrate that Sema3A-induced growth cone collapses are intimately related with increase in intracellular calcium concentration mediated by R-type calcium channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism*
  • Calcium / metabolism
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels, R-Type / metabolism*
  • Calcium Channels, T-Type / metabolism
  • Calcium Signaling / drug effects
  • Cell Line
  • Ganglia, Spinal / growth & development
  • Ganglia, Spinal / metabolism*
  • Gene Expression Profiling
  • Growth Cones / metabolism*
  • Growth Cones / pathology
  • HEK293 Cells
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Nickel / pharmacology
  • Semaphorin-3A / pharmacology*

Substances

  • Calcium Channel Blockers
  • Calcium Channels, R-Type
  • Calcium Channels, T-Type
  • SEMA3A protein, human
  • Semaphorin-3A
  • nickel chloride
  • Nickel
  • Calcium

Grants and funding

This work has been supported by Research Council of Lithuania (Grants MOS-7 and T40) and Student Research Fellowship Award for A. Kaselis (SDS-2012-014). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.