Regulation of early neurite morphogenesis by the Na+/H+ exchanger NHE1.
The ubiquitously expressed Na(+)/H(+) exchanger NHE1 plays an important role in regulating polarized membrane protrusion and directional motility in non-neuronal cells. Using NGF-differentiated PC12 cells and murine neocortical neurons in vitro, we now show that NHE1 plays a role in regulating early neurite morphogenesis. NHE1 was expressed in growth cones in which it gave rise to an elevated intracellular pH in actively extending neurites. The NHE1 inhibitor cariporide reversibly reduced growth cone filopodia number and the formation and elongation of neurites, especially branches, whereas the transient overexpression of full-length NHE1, but not NHE1 mutants deficient in either ion translocation activity or actin cytoskeletal anchoring, elicited opposite effects. In addition, compared with neocortical neurons obtained from wild-type littermates, neurons isolated from NHE1-null mice exhibited reductions in early neurite outgrowth, an effect that was rescued by overexpression of full-length NHE1 but not NHE1 mutants. Finally, the growth-promoting effects of netrin-1, but not BDNF or IGF-1, were markedly reduced by cariporide in wild-type neocortical neurons and were not observed in NHE1-null neurons. Although netrin-1 failed to increase growth cone intracellular pH or Na(+)/H(+) exchange activity, netrin-1-induced increases in early neurite outgrowth were restored in NHE1-null neurons transfected with full-length NHE1 but not an ion translocation-deficient mutant. Collectively, the results indicate that NHE1 participates in the regulation of early neurite morphogenesis and identify a novel role for NHE1 in the promotion of early neurite outgrowth by netrin-1.
Sin
Wun-Chey
WC
Department of Cellular and Physiological Sciences, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
Moniz
David M
DM
Ozog
Mark A
MA
Tyler
Jessica E
JE
Numata
Masayuki
M
Church
John
J
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport / Q000187:drug effects / Q000235:genetics; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D020439:Growth Cones / Q000187:drug effects / Q000502:physiology; D006146:Guanidines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism; D008565:Membrane Proteins / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation / Q000502:physiology; D019579:Neocortex / Q000166:cytology*; D020932:Nerve Growth Factor / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology; D000075388:Netrin-1; D016501:Neurites / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D016716:PC12 Cells / Q000166:cytology / Q000187:drug effects; D018408:Patch-Clamp Techniques / Q000379:methods; D011554:Pseudopodia / Q000235:genetics / Q000378:metabolism; D051381:Rats; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013450:Sulfones / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection / Q000379:methods; D025521:Tumor Suppressor Proteins / Q000494:pharmacology
D027682:Cation Transport Proteins; D006146:Guanidines; D008565:Membrane Proteins; D009414:Nerve Growth Factors; C000617353:Ntn1 protein, mouse; C000617354:Ntn1 protein, rat; C490997:Slc9a1 protein, mouse; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; D013450:Sulfones; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1; C093373:cariporide; D020932:Nerve Growth Factor; D007501:Iron