Intracerebroventricular antisense knockdown of G alpha i2 results in ciliary stasis and ventricular dilatation in the rat.
BACKGROUND
In the CNS, the heterotrimeric G protein Galphai2 is a minor Galpha subunit with restricted localization in the ventricular regions including the ependymal cilia. The localization of Galphai2 is conserved in cilia of different tissues, suggesting a particular role in ciliary function. Although studies with Galphai2-knockout mice have provided information on the role of this Galpha subunit in peripheral tissues, its role in the CNS is largely unknown. We used intracerebroventricular (icv) antisense administration to clarify the physiological role of Galphai2 in the ventricular system.


RESULTS
High resolution MRI studies revealed that continuous icv-infusion of Galphai2-specific antisense oligonucleotide caused unilateral ventricular dilatation that was restricted to the antisense-receiving ventricle. Microscopic analysis demonstrated ependymal cell damage and loss of ependymal cilia. Attenuation of Galphai2 in ependymal cells was confirmed by immunohistochemistry. Ciliary beat frequency measurements on cultured ependymal cells indicated that antisense administration resulted in ciliary stasis.


CONCLUSIONS
Our results establish that Galphai2 has an essential regulatory role in ciliary function and CSF homeostasis.
Mönkkönen
Kati S
KS
Department of Pharmacology & Toxicology, University of Kuopio, Kuopio, Finland. kati.monkkonen@uku.fi
Hakumäki
Juhana M
JM
Hirst
Robert A
RA
Miettinen
Riitta A
RA
O'Callaghan
Christopher
C
Männistö
Pekka T
PT
Laitinen
Jarmo T
JT
D000818:Animals; D001683:Biological Clocks / Q000235:genetics; D002478:Cells, Cultured; D002552:Cerebral Ventricles / Q000473:pathology / Q000502:physiology*; D002555:Cerebrospinal Fluid / Q000502:physiology; D002923:Cilia / Q000473:pathology / Q000502:physiology*; D004108:Dilatation, Pathologic / Q000235:genetics / Q000473:pathology; D004805:Ependyma / Q000473:pathology / Q000502:physiology; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000096:biosynthesis / Q000235:genetics*; D006706:Homeostasis / Q000235:genetics; D007276:Injections, Intraventricular; D008297:Male; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar
D016376:Oligonucleotides, Antisense; D051960:GTP-Binding Protein alpha Subunit, Gi2