Immortalized mouse inner ear cell lines demonstrate a role for chemokines in promoting the growth of developing statoacoustic ganglion neurons.
The target-derived factors necessary for promoting initial outgrowth from the statoacoustic ganglion (SAG) to the inner ear have not been fully characterized. In the present study, conditioned medium from embryonic Immortomouse inner ear cell lines that maintain many characteristics of developing inner ear sensory epithelia were screened for neurite-promoting activity. Conditioned medium found to be positive for promoting SAG neurite outgrowth and neuronal survival was then tested for the presence of chemokines, molecules that have not previously been investigated for promoting SAG outgrowth. One candidate molecule, monocyte chemotactic protein 1 (MCP-1), was detected in the conditioned medium and subsequently localized to mouse hair cells by immunocytochemistry. In vitro studies demonstrated that function-blocking MCP-1 antibodies decreased the amount of SAG neurite outgrowth induced by the conditioned medium and that subsequent addition of MCP-1 protein was able to promote outgrowth when added to the antibody-treated conditioned medium. The use of the Immortomouse cell lines proved valuable in identifying this candidate cofactor that promotes outgrowth of early-stage SAG nerve fibers and is expressed in embryonic hair cells.
Bianchi
Lynne M
LM
Neuroscience Department, Oberlin College, Oberlin, OH 44074, USA. lynne.bianchi@oberlin.edu
Daruwalla
Zeeba
Z
Roth
Therese M
TM
Attia
Naweah P
NP
Lukacs
Nicholas W
NW
Richards
Ayo-Lynn
AL
White
Ian O
IO
Allen
Susan J
SJ
Barald
Kate F
KF
D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D018932:Chemokine CCL2 / Q000032:analysis / Q000502:physiology; D018946:Chemokine CCL5 / Q000032:analysis / Q000502:physiology; D018925:Chemokines / Q000502:physiology*; D002634:Chemotaxis, Leukocyte; D002642:Chick Embryo; D017077:Culture Media, Conditioned; D007758:Ear, Inner / Q000166:cytology*; D005724:Ganglia / Q000166:cytology*; D051379:Mice; D009000:Monocytes / Q000276:immunology; D016501:Neurites / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000502:physiology
D018932:Chemokine CCL2; D018946:Chemokine CCL5; D018925:Chemokines; D017077:Culture Media, Conditioned; D014409:Tumor Necrosis Factor-alpha