A Comparison of Serum Vanin-1 Concentrations in Aquatically Adapted Mammals and Terrestrial Mammals using Mass Spectrometry

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Boxall, Baylye Katelyn
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A proteomic study of bottlenose dolphin serum identified and measured the highest concentration of pantetheinase (Vanin-1) for any mammal. Vanin-1 catalyzes the formation of the antioxidant cysteamine, from the vitamin B5 precursor, pantetheine. Because aquatic mammals have a high antioxidant capacity in their tissues and blood to counter dive-induced oxidative stress, it was hypothesized that elevated levels of Vanin-1 may represent an adaptation or response to diving. To test this, serum Vanin-1 concentrations were measured across closely related taxonomic groups of terrestrial and aquatic mammals by parallel reaction monitoring using stable isotope peptide standards. In members of Paenungulata, including hyraxes and manatees, Vanin-1 levels were high in manatees (mean=24.21 ug/mL, ±8.46), but not detectable in hyraxes. In Euungulata, Vanin-1 levels were high in 9 out of 10 cetacean species (range=2.87-106.38 ug/mL). High serum Vanin-1 seems to be characteristic of nearly all other members of Euungulata, including hippos (15.75 ug/mL, n=1), ruminants (range=2.32-45.60 ug/mL), and horses (mean=45.02 ug/mL, ±18.38). In Carnivora, serum Vanin-1 was only detected in 4 out 8 pinniped species (range=0.00-80.92 ug/mL) and not detected in any terrestrial species monitored. In Euarchontoglires, including humans, rodents, and rabbits, Vanin-1 was only detected in guinea pigs (mean=29 ug/mL, ± 5.99). Strangely, Vanin-1 was not detected in pigs, members of Euungulata. High serum Vanin-1 appears unique to aquatic mammals in Carnivora and Paenungulata, but not in Euungulata. In Euungulata, high serum Vanin-1 appears to be an ancestral state that was retained in cetaceans. Because Vanin-1 has been implicated as a marker of PPARα activity in the liver, these data may reflect broad phylogenetic differences in PPARα activity across mammals.