Hedgehog signaling pathway in the adrenal gland

—detection of Dhh—

Abstract

We identified a key signaling pathway associated with the adrenocortical autograft regeneration that has not been elucidated previously. Using the RNAscope technology, a novel in situ RNA hybridization assay, we found transient upregulation of Desert hedgehog (Dhh), a key signaling factor, and downregulation of Sonic hedgehog (Shh) in the process of graft regeneration. Interestingly, it had been reported that Dhh expression is localized to the gonadal tissues and its expression in the adrenal cortex has not been reported yet. Conversely, Shh-positive cells are known candidates for stem and progenitor cells in the adrenal cortex, but they exhibit little or no involvement in the process of adrenocortical graft regeneration. In addition to the previously known function of DHH in gonads, our findings suggest that it may further participate in the process of adrenocortical autograft regeneration. Our findings provide useful insights in the implementation of adrenal graft implantation and stem cell-derived adrenocortical cell generation. In this article, we will review our findings, the development of adrenal cortex, stem and progenitor cells, and other aspects.