Connexin 43 delimits functional domains of neurogenic precursors in the spinal cord.
The cells lining the central canal (CC) of the spinal cord derive from the ventral part of the neural tube and, in some vertebrates, are responsible for the functional recovery after spinal cord injury. The region that surrounds the CC in the turtle contains proliferating cells that seem to generate both glia and neurons. Understanding the biology of spinal progenitors with the potential to generate new neurons "in situ" is important for cell replacement therapies. Here, we aimed to identify and characterize precursor cells in the spinal cord of Trachemys dorbignyi. To evaluate the population of proliferating cells, 5-bromo-2'-deoxyuridine (BrdU) was injected every 4 h (50 microg/g, i.p.) during 24 h. We found BrdU(+) nuclei around the CC with a higher density in the lateral quadrants, in which whole-cell patch-clamp recordings showed extensive dye coupling of cells. Carbenoxolone (100 microM) increased the input resistance, suggesting strong gap junction coupling among precursors. The expression of brain lipid binding protein (a marker of a subtype of radial glia) and Pax6 matched the location of clusters, suggesting these cells belonged to a domain of neurogenic precursors. These domains were delimited by a high density of connexin 43 (Cx43) located on the endfeet of CC contacting cells. Our findings indicate that spinal precursors share basic properties with those in the embryo and neurogenic niches of the adult brain, and support a key role of functional clustering via Cx43 in spinal cord neurogenesis.
Russo
Raúl E
RE
Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, CP 11600 Montevideo, Uruguay. rrusso@iibce.edu.uy
Reali
Cecilia
C
Radmilovich
Milka
M
Fernández
Anabel
A
Trujillo-Cenóz
Omar
O
D000818:Animals; D002352:Carrier Proteins; D002454:Cell Differentiation / Q000502:physiology; D018031:Connexin 43 / Q000378:metabolism*; D004558:Electric Stimulation / Q000379:methods; D004625:Embryo, Nonmammalian; D005136:Eye Proteins / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology / Q000528:radiation effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism; D018408:Patch-Clamp Techniques; D012097:Repressor Proteins / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology*; D013234:Stem Cells / Q000502:physiology*; D013997:Time Factors; D014426:Turtles
D002352:Carrier Proteins; D018031:Connexin 43; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins