Pde8b haploinsufficiency in mice is associated with modest adrenal defects, impaired steroidogenesis, and male infertility, unaltered by concurrent PKA or Wnt activation

PDE8B, PRKAR1A and the Wnt/beta-catenin signaling are involved in endocrine disorders. However, how PDEB8B interacts with both Wnt and protein kinase A (PKA) signaling in vivo remains unknown. We created a novel Pde8b knockout mouse line (Pde8b(-/)(-)); Pde8b haploinsufficient (Pde8b(+/-)) mice were then crossed with mice harboring: (1) constitutive beta-catenin activation (Pde8b(+/)(-);Delta Cat) and (2) Prkar1a haploinsufficieny (Pde8b(+/-);Prkar1a(+/)(-)). Adrenals and testes from mice (3-12-mo) were evaluated in addition to plasma corticosterone, aldosterone and Dkk3 concentrations, and the examination of expression of steroidogenesis-, Wnt- and cAMP/PKA-related genes. Pde8b(-/-) male mice were infertile with down-regulation of the Wnt/beta-catenin pathway which did not change significantly in the Pde8b(+/-);Delta Cat mice. Prkarla haploinsufficiency also did not change the phenotype significantly. In vitro studies showed that PDE8B knockdown upregulated the Wnt pathway and increased proliferation in CTNNB1-mutant cells, whereas it downregulated the Wnt pathway in PRKAR1Amutant cells. These data support an overall weak, if any, role for PDE8B in adrenocortical tumorigenesis, even when co-altered with Wnt signaling or PKA upregulation; on the other hand, PDE8B appears to play a significant role in male fertility.

Automated summary

The study found that PDE8B has a weak role in endocrine disorders involving the Wnt/beta-catenin signaling and PKA signaling; PDE8B appears to play a significant role in male fertility.