Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms

Axon pathfinding and neuronal migration are orchestrated by attractive and repulsive guidance cues. In the mouse spinal cord, repulsion from Slit proteins through Robo family receptors and attraction to Netrin-1, mediated by the receptor DCC, control many aspects of neural circuit formation. This in...

Full description

Saved in:
Bibliographic Details
Main Authors: Kelsey R. Nickerson, Ferass M. Sammoura, Yonghong Zhou, Alexander Jaworski
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Cell and Developmental Biology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fcell.2025.1563403/full
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850185043125731328
author Kelsey R. Nickerson
Kelsey R. Nickerson
Ferass M. Sammoura
Ferass M. Sammoura
Yonghong Zhou
Yonghong Zhou
Alexander Jaworski
Alexander Jaworski
author_facet Kelsey R. Nickerson
Kelsey R. Nickerson
Ferass M. Sammoura
Ferass M. Sammoura
Yonghong Zhou
Yonghong Zhou
Alexander Jaworski
Alexander Jaworski
author_sort Kelsey R. Nickerson
collection DOAJ
description Axon pathfinding and neuronal migration are orchestrated by attractive and repulsive guidance cues. In the mouse spinal cord, repulsion from Slit proteins through Robo family receptors and attraction to Netrin-1, mediated by the receptor DCC, control many aspects of neural circuit formation. This includes motor neuron wiring, where Robos help prevent both motor neuron cell bodies and axons from aberrantly crossing the spinal cord midline. These functions had been ascribed to Robo signaling being required to counter DCC-mediated attraction to Netrin-1 at the midline, either by mediating repulsion from midline-derived Slits or by silencing DCC signaling. However, the role of DCC in promoting motor neuron and axon midline crossing had not been directly tested. Here, we used in vivo mouse genetics and in vitro axon turning assays to further explore the interplay between Slit and Netrin signaling in motor neuron migration and axon guidance relative to the midline. We find that DCC is a major driver of midline crossing by motor axons, but not motor neuron cell bodies, when Robo1 and Robo2 are knocked out. Further, in vitro results indicate that Netrin-1 attracts motor axons and that Slits can modulate the chemotropic response to Netrin-1, converting it from attraction to repulsion. Our findings indicate that Robo signaling allows both motor neuron cell bodies and axons to avoid the midline, but that only motor axons require this pathway to antagonize DCC-dependent midline attraction, which likely involves a combination of mediating Slit repulsion and directly influencing Netrin-DCC signaling output.
format Article
id doaj-art-dfa28b0c008c43ee9a52791533ffd9ff
institution OA Journals
issn 2296-634X
language English
publishDate 2025-04-01
publisher Frontiers Media S.A.
record_format Article
series Frontiers in Cell and Developmental Biology
spelling doaj-art-dfa28b0c008c43ee9a52791533ffd9ff2025-08-20T02:16:50ZengFrontiers Media S.A.Frontiers in Cell and Developmental Biology2296-634X2025-04-011310.3389/fcell.2025.15634031563403Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanismsKelsey R. Nickerson0Kelsey R. Nickerson1Ferass M. Sammoura2Ferass M. Sammoura3Yonghong Zhou4Yonghong Zhou5Alexander Jaworski6Alexander Jaworski7Department of Neuroscience, Brown University, Providence, RI, United StatesRobert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, United StatesDepartment of Neuroscience, Brown University, Providence, RI, United StatesRobert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, United StatesDepartment of Neuroscience, Brown University, Providence, RI, United StatesRobert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, United StatesDepartment of Neuroscience, Brown University, Providence, RI, United StatesRobert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, United StatesAxon pathfinding and neuronal migration are orchestrated by attractive and repulsive guidance cues. In the mouse spinal cord, repulsion from Slit proteins through Robo family receptors and attraction to Netrin-1, mediated by the receptor DCC, control many aspects of neural circuit formation. This includes motor neuron wiring, where Robos help prevent both motor neuron cell bodies and axons from aberrantly crossing the spinal cord midline. These functions had been ascribed to Robo signaling being required to counter DCC-mediated attraction to Netrin-1 at the midline, either by mediating repulsion from midline-derived Slits or by silencing DCC signaling. However, the role of DCC in promoting motor neuron and axon midline crossing had not been directly tested. Here, we used in vivo mouse genetics and in vitro axon turning assays to further explore the interplay between Slit and Netrin signaling in motor neuron migration and axon guidance relative to the midline. We find that DCC is a major driver of midline crossing by motor axons, but not motor neuron cell bodies, when Robo1 and Robo2 are knocked out. Further, in vitro results indicate that Netrin-1 attracts motor axons and that Slits can modulate the chemotropic response to Netrin-1, converting it from attraction to repulsion. Our findings indicate that Robo signaling allows both motor neuron cell bodies and axons to avoid the midline, but that only motor axons require this pathway to antagonize DCC-dependent midline attraction, which likely involves a combination of mediating Slit repulsion and directly influencing Netrin-DCC signaling output.https://www.frontiersin.org/articles/10.3389/fcell.2025.1563403/fullaxon guidanceneuronal migrationspinal cordmotor neuronrobo signalingcrosstalk
spellingShingle Kelsey R. Nickerson
Kelsey R. Nickerson
Ferass M. Sammoura
Ferass M. Sammoura
Yonghong Zhou
Yonghong Zhou
Alexander Jaworski
Alexander Jaworski
Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
Frontiers in Cell and Developmental Biology
axon guidance
neuronal migration
spinal cord
motor neuron
robo signaling
crosstalk
title Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
title_full Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
title_fullStr Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
title_full_unstemmed Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
title_short Slit-Robo signaling supports motor neuron avoidance of the spinal cord midline through DCC antagonism and other mechanisms
title_sort slit robo signaling supports motor neuron avoidance of the spinal cord midline through dcc antagonism and other mechanisms
topic axon guidance
neuronal migration
spinal cord
motor neuron
robo signaling
crosstalk
url https://www.frontiersin.org/articles/10.3389/fcell.2025.1563403/full
work_keys_str_mv AT kelseyrnickerson slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT kelseyrnickerson slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT ferassmsammoura slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT ferassmsammoura slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT yonghongzhou slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT yonghongzhou slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT alexanderjaworski slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms
AT alexanderjaworski slitrobosignalingsupportsmotorneuronavoidanceofthespinalcordmidlinethroughdccantagonismandothermechanisms