The discovery of precursor cells and neurogenesis in postnatal dorsal root sensory ganglia
Notice bibliographique
Résumé
Neurogenesis is known to continue in various regions of the central nervous system (CNS) throughout life. However, it is currently unknown whether the same can be said for the dorsal root ganglia (DRG) of the peripheral nervous system (PNS). The mitogen, basic fibroblast growth factor (bFGF) has been previously demonstrated to induce proliferation of CNS neuronal precursors in culture. Since it has also been shown that bFGF is up-regulated within DRG following axotomy, it is quite possible t at the DRG also contains bFGF-responsive neuronal precursors. As a result, 'in vitro' and 'in vivo' experiments were undertaken in order to explore this possibility. The addition of bFGF to cell cultures of early postnatal DRG induced a proliferative response that became evident by the formation of spherical aggregates that stained for the CNS stem cell marker nestin. The replacement of bFGF with trophic factors induced similar cell clusters to differentiate into cells that morphologically resembled DRG neurons, stained for neuronal markers, and generated action potentials. Furthermore, bromodeoxyuridine (BrdU), used as a marker of cytogenesis, was detected in neurofilament-160 + (NF-160+) and/or microtubule associated protein + (MAP-2)+ cells that morphologically resembled neurons. Nerve growth factor (NGF) and sonic hedgehog (Shh) were also capable of producing spherical, process bearing, cell aggregates that stained for neuronal markers. Thus, the DRG appears to contain neuronal precursors that can proliferate in response to several mitogens. Sciatic nerve lesion experiments in juvenile rats were employed to demonstrate that neurogenesis occurs normally following nerve injury. These studies demonstrated a consistent ~40% relative increase in proliferating cells (BrdU +) on the lesioned side compared to the contralateral unlesioned DRG. This observed proliferative response appeared to be greater at 1 week than 2 weeks postaxotomy. Many BrdU+ cells also appeared to stain for the neuronal marker neuron-specific enolase (NSE) suggesting the presence of neuronal precursors. These double-labeled cells were preferentially upregulated in the ipsilateral ganglia, reaching maximal numbers within the first 48 hour after nerve transection. However, this upregulation was transient, lasting for only 1 week. Similar cells (BrdU+/NSE+) were also identified in adult DRG post-axotomy. In addition, BrdU+ labeling in neurons previously anterogradely labeled with Flouro-Gold suggest that pre-existing neurons within adult DRG can become mitotic. These results support the hypothesis that DRG contain neural precursors throughout life that can proliferate and subsequently differentiate into neurons in response to injury. These findings may indicate a greater range of plasticity that is available to somatosensory systems during maturation and following injury, perhaps to replace ineffectual or dying neurons.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».