Functional profiles of SCN9A variants in dorsal root ganglion neurons and superior cervical ganglion neurons correlate with autonomic symptoms in small fibre neuropathy

Autor: Sulayman D. Dib-Hajj, Janneke G. J. Hoeijmakers, Shujun Liu, Chongyang Han, Giuseppe Lauria, Ingemar S. J. Merkies, Rene H. M. te Morsche, Catharina G. Faber, Monique M. Gerrits, Stephen G. Waxman, Joost P.H. Drenth
Přispěvatelé: Gastroenterology & Hepatology, Neurology, Promovendi MHN, Klinische Neurowetenschappen, MUMC+: DA KG Lab Centraal Lab (9), Genetica & Celbiologie, RS: CARIM School for Cardiovascular Diseases, RS: MHeNs School for Mental Health and Neuroscience, RS: GROW - School for Oncology and Reproduction
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Brain, 135, 2613-28
Brain, 135, Pt 9, pp. 2613-28
Brain, 135, 2613-2628. Oxford University Press
ISSN: 1460-2156
0006-8950
Popis: Item does not contain fulltext Patients with small fibre neuropathy typically manifest pain in distal extremities and severe autonomic dysfunction. However, occasionally patients present with minimal autonomic symptoms. The basis for this phenotypic difference is not understood. Sodium channel Na(v)1.7, encoded by the SCN9A gene, is preferentially expressed in the peripheral nervous system within sensory dorsal root ganglion and sympathetic ganglion neurons and their small diameter peripheral axons. We recently reported missense substitutions in SCN9A that encode functional Na(v)1.7 variants in 28% of patients with biopsy-confirmed small fibre neuropathy. Two patients with biopsy-confirmed small fibre neuropathy manifested minimal autonomic dysfunction unlike the other six patients in this series, and both of these patients carry the Na(v)1.7/R185H variant, presenting the opportunity to compare variants associated with extreme ends of a spectrum from minimal to severe autonomic dysfunction. Herein, we show by voltage-clamp that R185H variant channels enhance resurgent currents within dorsal root ganglion neurons and show by current-clamp that R185H renders dorsal root ganglion neurons hyperexcitable. We also show that in contrast, R185H variant channels do not produce detectable changes when studied by voltage-clamp within sympathetic neurons of the superior cervical ganglion, and have no effect on the excitability of these cells. As a comparator, we studied the Na(v)1.7 variant I739V, identified in three patients with small fibre neuropathy characterized by severe autonomic dysfunction as well as neuropathic pain, and show that this variant impairs channel slow inactivation within both dorsal root ganglion and superior cervical ganglion neurons, and renders dorsal root ganglion neurons hyperexcitable and superior cervical ganglion neurons hypoexcitable. Thus, we show that R185H, from patients with minimal autonomic dysfunction, does not produce detectable changes in the properties of sympathetic ganglion neurons, while I739V, from patients with severe autonomic dysfunction, has a profound effect on excitability of sympathetic ganglion neurons.
Databáze: OpenAIRE