Transcriptomic plasticity of the hypothalamic osmoregulatory control centre of the Arabian dromedary camel

Abstract Water conservation is vital for life in the desert. The dromedary camel (Camelus dromedarius) produces low volumes of highly concentrated urine, more so when water is scarce, to conserve body water. Two hormones, arginine vasopressin (AVP) and oxytocin (OXT), both produced in the supraoptic nucleus (SON), the core hypothalamic osmoregulatory control centre, are vital for this adaptive process, but the mechanisms that enable the camel SON to cope with osmotic stress are not known. To investigate the central control of water homeostasis in the camel, we first built three dimensional models of the camel SON based on the expression of the AVP and OXT mRNAs in order to facilitate sampling. We then compared the transcriptomes of the SON under control and WD conditions and identified genes that change in expression due to hyperosmotic stress. By comparing camel and rat datasets, we have identified common elements of the WD transcriptomic response network, as well as elements, such as extracellular matrix remodelling and upregulation of angiotensinogen expression, that appear to be unique to the dromedary camel and that may be essential adaptations necessary for life in the desert.