title: Endogenous neurotrophic factors enhance neurite growth by bag cell neurons of Aplysia.
abstract: Mechanisms that regulate neurite outgrowth are phylogenetically conserved, including the signaling molecules involved. Here, we describe neurotrophic effects on isolated bag cell neurons (BCNs) of substrate-bound growth factors endogenous to the sea slug Aplysia californica. Sheath cells dissociated from the pleural-visceral connectives of the Aplysia CNS and arterial cells dissociated from the anterior aorta enhance neurite outgrowth when compared to controls, i.e., BCNs grown in defined medium alone. In addition, the substrate remaining after sheath cells or arterial cells are killed significantly enhances growth, relative to all other conditions tested. For instance, primary neurites are more numerous and greater in length for BCNs cultured on substrate produced by arterial cells. These results suggest that sheath and arterial cells produce growth-promoting factors, some of which are found in the substrates produced by these cell types. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), we found that Aplysia collagen-like peptides are produced by dissociated arterial cells, and therefore likely contribute to the observed growth effects. Collagen-like peptides and other factors produced by sheath and arterial cells likely influence neurite growth in the Aplysia CNS during development, learning and memory, and regeneration after injury.
authors.affiliation: Division of Biological Sciences, University of Missouri-Columbia, 101 Lefevre Hall, Columbia, Missouri 65211, USA.
authors.forename: Binaben H
authors.initials: BH
authors.lastname: Vanmali
authors.forename: Elena V
authors.initials: EV
authors.lastname: Romanova
authors.forename: Maria C
authors.initials: MC
authors.lastname: Messner
authors.forename: Mona
authors.initials: M
authors.lastname: Singh
authors.forename: Joel
authors.initials: J
authors.lastname: Maruniak
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sweedler
authors.forename: Mark D
authors.initials: MD
authors.lastname: Kirk
mesh_terms: D000818:Animals; D001011:Aorta / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D001048:Aplysia / Q000166:cytology / Q000502:physiology*; D002352:Carrier Proteins; D002478:Cells, Cultured; D002490:Central Nervous System / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D018920:Coculture Techniques; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D009414:Nerve Growth Factors / Q000502:physiology*; D016501:Neurites / Q000502:physiology* / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism; D010455:Peptides / Q000032:analysis; D011506:Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D002352:Carrier Proteins; D009414:Nerve Growth Factors; D009479:Neuropeptides; D010455:Peptides; D011506:Proteins; C007105:c1q-binding proteins; C052709:histidine rich basic peptide (Aplysia)