Tissue-specific expression of lipid metabolism genes in caiman

Abstract

Environmental contamination by chemical mixtures poses a growing threat to wildlife metabolic homeostasis, as many pollutants can disrupt lipid metabolism by acting on nuclear receptors, affecting energy balance, reproduction and immune response. However, little is known about these pathways in reptiles, especially crocodilians. This study aimed to identify and characterize the expression patterns of key genes of lipid metabolism homeostasis - glucose-6-phosphate dehydrogenase (g-6-pdh), fatty acid synthase (fas), malic enzyme (me), lipoprotein lipase (lpl), peroxisome proliferator-activated receptor alpha (pparα), peroxisome proliferator-activated receptor gamma (pparγ), and sterol regulatory element-binding protein 1c (srebp-1c) across different tissues (spleen, liver, intestine, gonads and peripheral blood) of Caiman latirostris, to assess their potential as biomarkers of the effect of xenobiotics exposure. Semi-quantitative PCR analyses revealed that while all target genes were expressed in every tissue, their relative expression levels differed significantly, with the liver showing the highest expression for most genes. Phylogenetic relationships with other sauropsids showed highly conserved functional domain similarities and regions for these genes. Importantly, peripheral blood exhibited detectable expression of all genes, supporting its use as a minimally invasive tissue for monitoring gene expression in wild populations. These findings provide foundational knowledge on lipid metabolism in crocodilians and propose candidate molecular biomarkers for future studies assessing metabolic disruption due to environmental contaminants.