Annexin III implicated in the microglial response to motor nerve injury.

Abstract

To identify proteins implicated in peripheral nerve regeneration, we performed two-dimensional polyacrylamide gel electrophoresis and subsequent mass spectrometry analysis using nerve-injured hypoglossal nuclei of rat. We have identified annexin III (ANX III/ANX A3) as an induced protein after rat hypoglossal nerve injury. ANX III is known as a Ca2+-dependent phospholipid-binding protein, but its physiological function is mostly unknown. By in situ hybridization and immunohistochemistry, we demonstrated that ANX III expression was induced specifically in activated (axotomy-stimulated) microglia after nerve injury. ANX III was the most prominent ANX expressed in microglia of the major ANX family members (ANX I-VI). Hybridization signals for other ANX mRNAs (II, IV, V, and VI) were mainly observed in neuronal cells, and no significant hybridization signal for ANX I mRNA was detected in hypoglossal nuclei. In cultured microglia, ATP treatment induced ANX III translocation to the ruffling membrane where F-actin was accumulated. Further in vitro studies revealed that ANX III was not secreted and had F-actin binding activity in a Ca2+-dependent manner. These results suggest that ANX III may be a Ca2+-dependent mediator between phospholipids and F-actin in microglia stimulated by peripheral nerve injury.

• Authors: Hiroyuki Konishi, Kazuhiko Namikawa, Hiroshi Kiyama
• Journal: Glia (Glia) Vol. 53 Issue 7 Pg. 723-32 (May 2006) ISSN: 0894-1491 [Print] United States
• PMID: 16506224 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2006 Wiley-Liss, Inc.

Chemical References

• Actins
• Phospholipids
• RNA, Messenger
• Annexin A3

Topics

• Actins (metabolism)
• Animals
• Animals, Newborn
• Annexin A3 (genetics, metabolism)
• Axons (metabolism)
• Calcium Signaling (physiology)
• Cell Membrane (metabolism)
• Cell Movement (physiology)
• Cells, Cultured
• Gliosis (genetics, metabolism, physiopathology)
• Hypoglossal Nerve (cytology, metabolism)
• Hypoglossal Nerve Diseases (metabolism, physiopathology)
• Hypoglossal Nerve Injuries
• Male
• Microglia (metabolism)
• Motor Neurons (metabolism)
• Nerve Regeneration (physiology)
• Peripheral Nerve Injuries
• Peripheral Nerves (cytology, metabolism)
• Phospholipids (metabolism)
• Protein Binding (physiology)
• Protein Transport (physiology)
• RNA, Messenger
• Rats
• Rats, Wistar
• Up-Regulation (physiology)