title: The high molecular weight neurofilament subunit plays an essential role in axonal outgrowth and stabilization.
abstract: Neurofilaments (NFs) are thought to provide structural support to mature axons via crosslinking of cytoskeletal elements mediated by the C-terminal region of the high molecular weight NF subunit (NF-H). Herein, we inhibited NF-H expression in differentiating mouse NB2a/d1 cells with shRNA directed against murine NF-H without affecting other NF subunits, microtubules or actin. shRNA-mediated NF-H knockdown not only in compromised of late-stage axonal neurite stabilization but also compromised early stages of axonal neurite elongation. Expression of exogenous rat NF-H was able to compensate for knockdown of endogenous NF-H and restored the development and stabilization of axonal neurites. This rescue was prevented by simultaneous treatment with shRNA that inhibited both rat and murine NF-H, or by expression of exogenous rat NF-H lacking the C-terminal sidearm during knockdown of endogenous NF-H. Demonstration of a role for NF-H in the early stages of axonal elaboration suggests that axonal stabilization is not delayed until synaptogenesis, but rather that the developing axon undergoes sequential NF-H-mediated stabilization along its length in a proximal-distal manner, which supports continued pathfinding in distal, unstabilized regions.
authors.affiliation: Center for Cellular Neurobiology and Neurodegeneration Research, Department of Biological Sciences, University of Massachusetts at Lowell, Lowell, MA 01854, USA.
authors.forename: Sangmook
authors.initials: S
authors.lastname: Lee
authors.affiliation: Center for Cellular Neurobiology and Neurodegeneration Research, Department of Biological Sciences, University of Massachusetts at Lowell, Lowell, MA 01854, USA.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Shea
keywords: Axonal outgrowth; Axonal stability; Cytoskeleton; Nervous system development; Neurofilament