Multiomic analysis of the Arabian camel (Camelus dromedarius) kidney reveals a role for cholesterol in water conservation

Abstract

The Arabian camel (Camelus dromedarius) is the most important livestock animal in arid and semi-arid regions and provides basic necessities to millions of people. In the current context of climate change, there is renewed interest in the mechanisms that enable camelids to survive in arid conditions. Recent investigations described genomic signatures revealing evolutionary adaptations to desert environments. We now present a comprehensive catalogue of the transcriptomes and proteomes of the dromedary kidney and describe how gene expression is modulated as a consequence of chronic dehydration and acute rehydration. Our analyses suggested an enrichment of the cholesterol biosynthetic process and an overrepresentation of categories related to ion transport. Thus, we further validated differentially expressed genes with known roles in water conservation which are affected by changes in cholesterol levels. Our datasets suggest that suppression of cholesterol biosynthesis may facilitate water retention in the kidney by indirectly facilitating the AQP2-mediated water reabsorption.

Comparative physiological, morphological, histological, and AQP2 immunohistochemical analysis of the Arabian camels (Camelus dromedarius) and oxen kidney: Effects of adaptation to arid environments

“…The immune expression in the case of dromedaries showed strong expression of the lining epithelium of collecting tubules and the moderate reaction of the loop of Henle (Khafaga et al, 2021). Altogether, these data strongly suggest that dromedaries can produce highly concentrated urine, which was ensured by Alvira-Iraizoz et al (2021) who revealed that water retention in the kidney indirectly facilitated by the AQP2-mediated water reabsorption. However, the specific function and underlying mechanisms of this observation are not clear and should further be investigated.…”

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

“…We looked to one of nature’s water conserving wonders, the camel, to provide answers and molecular insights into the specialisations that ensure survival in these environments. Having recently reported transcriptomic and proteomic adaptations to WD in the camel kidney 40 , we turned our attention to the hypothalamic neuroendocrine mechanisms responsible for orchestrating the response to WD. This is the first time that the camel brain has been so extensively studied in terms of its adaptations to the desert environment.…”

Structural and functional genomics in Old World camels—where do we stand and where to go

“…In Old World camels, de novo whole-genome sequencing including shot-gun, long reads, and structural Hi-C mapping was used to build high-quality reference genomes on chromosome levels ( Elbers et al , 2019 ; Ming et al , 2020 and references therein). Multiomic, i.e., transcriptomic and proteomic analyses of dromedary ( Alvira-Iraizoz et al , 2021 ) and Bactrian camel ( Wu et al , 2014 ) kidney tissues complemented and advanced these important first steps towards understanding the structure and function of camelid genomes. Building on these newly available high-quality reference genomes, polymorphism and structural and functional analyses of targeted regions were performed, and initial genome-wide association studies were launched.…”