Search

Summary: The recent development of single-cell and single-nucleus RNA sequencing has highlighted the extraordinary diversity of dorsal root ganglia neurons. However, the few available genetic tools limit our understanding of the functional significance of this heterogeneity. We generated a new mouse line expressing the flippase recombinase from the scn10a locus. By crossing Nav1.8Ires−FLPo mice with the AdvillinCre and RC::FL-hM3Dq mouse lines in an intersectional genetics approach, we were able to obtain somatodendritic expression of hM3Dq-mCherry selectively in the Nav1.8 lineage. The bath application of clozapine N-oxide triggered strong calcium responses selectively in mCherry+ neurons. The intraplantar injection of CNO caused robust flinching, shaking, and biting responses accompanied by strong cFos activation in the ipsilateral lumbar spinal cord. The Nav1.8Ires−FLPo mouse model will be a valuable tool for extending our understanding of the in vivo functional specialization of neuronal subsets of the Nav1.8 lineage for which inducible Cre lines are available.

Primary aldosteronism (PA) is the most common form of secondary hypertension. Mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D are found in aldosterone producing adenoma (APA) and familial hyperaldosteronism (FH). A recurrent mutation in CACNA1H (coding for Cav3.2) was identified in a familial form of early onset PA. Here we performed whole exome sequencing (WES) in patients with different types of PA to identify new susceptibility genes. Four different heterozygous germline CACNA1H variants were identified. A de novo Cav3.2 p.Met1549Ile variant was found in early onset PA and multiplex developmental disorder. Cav3.2 p.Ser196Leu and p.Pro2083Leu were found in two patients with FH, and p.Val1951Glu was identified in one patient with APA. Electrophysiological analysis of mutant Cav3.2 channels revealed significant changes in the Ca2+ current properties for all mutants, suggesting a gain of function phenotype. Transfections of mutant Cav3.2 in H295R-S2 cells led to increased aldosterone production and/or expression of genes coding for steroidogenic enzymes after K+ stimulation. Identification of CACNA1H mutations associated with early onset PA, FH, and APA suggests that CACNA1H might be a susceptibility gene predisposing to PA with different phenotypic presentations, opening new perspectives for genetic diagnosis and management of patients with PA.