Distribution of TGF-beta, the TGF-beta type I receptor and the R-II receptor in peripheral nerves and mechanoreceptors; observations on changes after traumatic injury.
The mechanisms governing the regeneration of denervated peripheral mechanoreceptors are similar to those of peripheral nerves. The ability to regenerate depends partly on changes of the Schwann cell phenotype. The transforming growth factor beta (TGF-beta) family have been implicated in induction of Schwann cell proliferation, production of extracellular matrix and neurotrophin synthesis as well as synthesis or repression of cell adhesion molecules. Hence, they may prove to be of importance for regenerative mechanisms in peripheral mechanoreceptors. The distribution of TGF-beta, the receptors I and II and intra-cellular second messengers, Smad 2/3 and 4 was assessed in sensory neurones, peripheral nerves and mechanoreceptors by immuno-histochemistry, immuno-electron microscopy and in situ hybridisation. TGF-beta2 mRNA and TGF-beta2-like immunoreactivity (IR) were expressed in injured small and medium sized rat sensory neurones of dorsal root ganglia. TGF-beta and receptor II mRNA and immunoreactivities (IR) were present in satellite cells. Intact and injured sensory neurones expressed receptor I mRNA and Smad 2 mRNA. TGF-beta2 mRNA was found in transected nerve stumps and in sensory mechanoreceptors. TGF-beta1, 2 and Smad 4 were also observed in inner core lamellar cells of intact and denervated cat Pacinian corpuscles. Lamellar cells of intact and denervated Meissner corpuscles were TGF-beta immunoreactive. Merkel cells were receptors I and II immunoreactive. In conclusion, cutaneous and subcutaneous mechanoreceptors differ with regard to the expression of TGF-beta isoforms and receptors.
Stark
B
B
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden. birgit.stark@neuro.ki.se
Carlstedt
T
T
Risling
M
M
D030201:Activin Receptors, Type I / Q000378:metabolism*; D000818:Animals; D002415:Cats; D048429:Cell Size / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D005727:Ganglia, Spinal / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D008465:Mechanoreceptors / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D008854:Microscopy, Electron; D009413:Nerve Fibers, Myelinated / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D009416:Nerve Regeneration / Q000502:physiology*; D009475:Neurons, Afferent / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D015388:Organelles / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D027161:Satellite Cells, Perineuronal / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D012584:Sciatic Nerve / Q000293:injuries / Q000503:physiopathology / Q000601:surgery; D012867:Skin / Q000294:innervation / Q000378:metabolism; D051899:Smad2 Protein; D051901:Smad4 Protein; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3
D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D051901:Smad4 Protein; C490811:Smad4 protein, rat; C508962:Tgfb1 protein, rat; C509046:Tgfb3 protein, rat; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; C000625843:Tgfbr1 protein, rat