zG CreERT2 Uncovers Migration and Sex-Dependent NPC1 in Aldosterone Synthesis

BACKGROUND: The adrenal zona glomerulosa (zG) is the primary site of aldosterone synthesis. Inducible genetic tools are important for investigating zG cell function and fate in adult mice. This study aimed to generate and validate a tamoxifen-inducible, zG-specific aldosterone synthase–CreERT2 mouse model and investigate the zG-specific role of NPC1 (Niemann-Pick type C1) in aldosterone synthesis. METHODS: Aldosterone synthase-CreERT2 mice were generated by clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat–associated 9 knock-in of P2A (porcine teschovirus-1 2A peptide)-CreERT2 into the Cyp11b2 locus. Cre specificity and efficiency were validated by quantitative polymerase chain reaction, immunofluorescence, and lineage tracing. The model was then used to conditionally delete Npc1 in the zG. RESULTS: Cre expression and activity were confined to the zG. Heterozygous aldosterone synthase–CreERT2 mice showed normal adrenal morphology and hormone levels despite reduced Cyp11b2 expression. Homozygosity of the CreERT2 allele significantly reduced Cyp11b2 expression and aldosterone levels and increased renin in both sexes, indicating a gene-dosage effect. Lineage tracing confirmed the centripetal migration of zG cells to the zona fasciculata, which was faster in female mice. Strikingly, zG-specific Npc1 deletion reduced aldosterone in female mice under a normal-sodium diet, whereas increased renin and decreased aldosterone-to-renin ratio were observed in male mice under a high-sodium diet, indicating a sex-dependent effect. CONCLUSIONS: The aldosterone synthase–CreERT2 mouse provides a powerful and specific platform for spatiotemporally controlled dissection of zG biology, with the heterozygous line recommended for use to avoid Cre-associated dosage effects. Using this model, we identify a sex-dependent effect of zG-specific Npc1 deletion on aldosterone regulation, providing new insight into sex differences in adrenal physiology and aldosterone-related disorders.