Deletion of Tsc2 in Nociceptors Reduces Target Innervation, Ion Channel Expression, and Sensitivity to Heat

Dan Carlin, Judith P. Golden, Amit Mogha, Vijay K. Samineni, Kelly Monk, Robert W. Gereau, Valeria Cavalli

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The mechanistic target of rapamycin complex 1 (mTORC1) is known to regulate cellular growth pathways, and its genetic activation is sufficient to enhance regenerative axon growth following injury to the central or peripheral nervous systems. However, excess mTORC1 activation may promote innervation defects, and mTORC1 activity mediates injury-induced hypersensitivity, reducing enthusiasm for the pathway as a therapeutic target. While mTORC1 activity is required for full expression of some pain modalities, the effects of pathway activation on nociceptor phenotypes and sensory behaviors are currently unknown. To address this, we genetically activated mTORC1 in mouse peripheral sensory neurons by conditional deletion of its negative regulator Tuberous Sclerosis Complex 2 (Tsc2). Consistent with the well-known role of mTORC1 in regulating cell size, soma size and axon diameter of C-nociceptors were increased in Tsc2-deleted mice. Glabrous skin and spinal cord innervation by C-fiber neurons were also disrupted. Transcriptional profiling of nociceptors enriched by fluorescence-associated cell sorting (FACS) revealed downregulation of multiple classes of ion channels as well as reduced expression of markers for peptidergic nociceptors in Tsc2-deleted mice. In addition to these changes in innervation and gene expression, Tsc2-deleted mice exhibited reduced noxious heat sensitivity and decreased injury-induced cold hypersensitivity, but normal baseline sensitivity to cold and mechanical stimuli. Together, these data show that excess mTORC1 activity in sensory neurons produces changes in gene expression, neuron morphology and sensory behavior.

Original languageEnglish (US)
JournaleNeuro
Volume5
Issue number2
DOIs
StatePublished - Mar 1 2018

Fingerprint

Nociceptors
Tuberous Sclerosis
Ion Channels
Hot Temperature
Sensory Receptor Cells
Axons
Wounds and Injuries
Gene Expression
Unmyelinated Nerve Fibers
Peripheral Nervous System
Carisoprodol
Growth
Tuberous Sclerosis 2
mechanistic target of rapamycin complex 1
Cell Size
Spinal Cord
Hypersensitivity
Down-Regulation
Central Nervous System
Fluorescence

Keywords

  • CGRP
  • DRG
  • mTOR
  • nociceptor
  • pain
  • Tsc2

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Deletion of Tsc2 in Nociceptors Reduces Target Innervation, Ion Channel Expression, and Sensitivity to Heat. / Carlin, Dan; Golden, Judith P.; Mogha, Amit; Samineni, Vijay K.; Monk, Kelly; Gereau, Robert W.; Cavalli, Valeria.

In: eNeuro, Vol. 5, No. 2, 01.03.2018.

Research output: Contribution to journalArticle

Carlin, Dan ; Golden, Judith P. ; Mogha, Amit ; Samineni, Vijay K. ; Monk, Kelly ; Gereau, Robert W. ; Cavalli, Valeria. / Deletion of Tsc2 in Nociceptors Reduces Target Innervation, Ion Channel Expression, and Sensitivity to Heat. In: eNeuro. 2018 ; Vol. 5, No. 2.
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