Role of aspartyl-(asparaginyl)-β-hydroxylase mediated notch signaling in cerebellar development and function.
BACKGROUND
Aspartyl-(Asparaginyl)-β-Hydroxylase (AAH) is a hydroxylating enzyme that promotes cell motility by enhancing Notch-Jagged-HES-1 signaling. Ethanol impaired cerebellar neuron migration during development is associated with reduced expression of AAH.


METHODS
To further characterize the role of AAH in relation to cerebellar development, structure, and function, we utilized an in vivo model of early postnatal (P2) intracerebro-ventricular gene delivery to silence AAH with small interfering RNA (siAAH), or over-express it with recombinant plasmid DNA (pAAH). On P20, we assessed cerebellar motor function by rotarod testing. Cerebella harvested on P21 were used to measure AAH, genes/proteins that mediate AAH's downstream signaling, i.e. Notch-1, Jagged-1, and HES-1, and immunoreactivity corresponding to neuronal and glial elements.


RESULTS
The findings demonstrated that: 1) siAAH transfection impaired motor performance and blunted cerebellar foliation, and decreased expression of neuronal and glial specific genes; 2) pAAH transfection enhanced motor performance and increased expression of neuronal and glial cytoskeletal proteins; and 3) alterations in AAH expression produced similar shifts in Notch-1, Jagged-1, and HES-1 protein or gene expression.


CONCLUSIONS
The results support our hypothesis that AAH is an important mediator of cerebellar development and function, and link AAH expression to Notch signaling pathways in the developing brain.
Warren Alpert Medical School of Brown University, Providence, RI, USA.
Elizabeth
E
Silbermann
Peter
P
Moskal
Nathaniel
N
Bowling
Ming
M
Tong
Suzanne M
SM
de la Monte
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002531:Cerebellum / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D018014:Gene Transfer Techniques; D018398:Homeodomain Proteins / Q000378:metabolism; D007276:Injections, Intraventricular; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000502:physiology*; D010957:Plasmids / Q000235:genetics; D011597:Psychomotor Performance / Q000502:physiology; D034741:RNA, Small Interfering / Q000008:administration & dosage; D051381:Rats; D020318:Rats, Long-Evans; D051881:Receptor, Notch1 / Q000378:metabolism*; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction / Q000502:physiology*; D000072056:Transcription Factor HES-1
D051792:Basic Helix-Loop-Helix Proteins; D002135:Calcium-Binding Proteins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D006899:Mixed Function Oxygenases; D034741:RNA, Small Interfering; D051881:Receptor, Notch1; D000072099:Serrate-Jagged Proteins; D000072056:Transcription Factor HES-1; C489735:Hes1 protein, rat; C000606275:Jag1 protein, rat; C058291:aspartic acid 2-oxoglutarate-dependent dioxygenase