Triphenyltin alters lipid homeostasis in females of the ramshorn snail Marisa cornuarietis

Abstract

Molluscs are sensitive species to the toxic effects of organotin compounds, particularly to masculinisation. Both tributyltin (TBT) and triphenyltin (TPT) have been recently shown to bind to mollusc retinoid X receptor (RXR). If RXR is involved in lipid homeostasis, exposure to TPT would have an immediate effect on endogenous lipids. To test this hypothesis, the ramshorn snail Marisa cornuarietis was exposed to environmentally relevant concentrations of TPT (30, 125, 500 ng/L as Sn) in a semi-static water regime for 7 days. Percentage of lipids and total fatty acid content decreased significantly in TPT-exposed females while the activity of peroxisomal acyl-CoA oxidase, involved in fatty acid catabolism, increased. In addition, fatty acid profiles (carbon chain length and unsaturation degree) were significantly altered in exposed females but not in males. This work highlights the ability of TPT to disrupt lipid metabolism in M. cornuarietis at environmentally realistic concentrations and the higher susceptibility of females in comparison to males.

Structural and functional changes in gill mitochondrial membranes from the Mediterranean mussel Mytilus galloprovincialis exposed to tri‐n‐butyltin

“…In the rock shell Thais clavigera, TBT has been reported to bind with high affinity to RXR [33]; in longterm TBT-exposed Marisa cornuarietis, changes in the fatty acid profile and especially the PUFA drop were suggested as RXR or RXR-PPARg-mediated [34]. Accordingly, the observed decrease in 22:6 n-3 in gill mitochondria, consistent with the total and n-3 PUFA decrease in TBT-exposed mussels compared to control ones, is in good agreement with findings in M. cornuarietis exposed for one week to similar doses of triphenyltin and related to RXR involvement in lipid homeostasis [35]. However, on considering the PUFA signaling role in PPARg activation, feedback mechanisms involving PUFA as potential regulators of lipid metabolism in mussels cannot be discarded.…”

Obesogens

“…In addition, organotin exposure results in broad disruptions of lipid homeostasis. Short-term exposure to environmental levels of TPT (30-500 ng/l as Sn) led to transcriptional induction of lipid catabolic enzymes, changes in lipid profiles and a significant decrease in total fatty acids in the digestive/gonadal complex of female ramshorn snails [48]. In contrast, long-term exposure studies with TBT induced an obesogenic effect with percentage of lipid and total fatty acid content being 2-3-fold greater in treated than control females [49].…”

Esterification of vertebrate like steroids in molluscs: A target of endocrine disruptors?

“…516 Another study showed that ATAT activity in microsomal fractions isolat-517 ed from digestive gland/gonad complex of M. cornuarietis was signifi-518 cantly increased in males following exposure to 500 ng/L TBT during 519 50 days . (Lyssimachou et al, 2008(Lyssimachou et al, , 2009a. In 535 this species, the percentage of lipids, total fatty acid content, carbon 536 chain length and unsaturation degree decreased in digestive gland/ 537 gonad complexes of females exposed to TPT for 7 days while no 538 differences were observed in males (Lyssimachou et al, 2009a).…”

“…(Lyssimachou et al, 2008(Lyssimachou et al, , 2009a. In 535 this species, the percentage of lipids, total fatty acid content, carbon 536 chain length and unsaturation degree decreased in digestive gland/ 537 gonad complexes of females exposed to TPT for 7 days while no 538 differences were observed in males (Lyssimachou et al, 2009a). 539 An increase in activity of palmitoyl-CoA oxidase, an enzyme 540 responsible for the breakdown of C14-C18 and C N 20 fatty acids, 541 was also observed in males exposed to TPT at 30 ng Sn/L and in fe-542 males exposed to 30 and 500 ng Sn/L as TPT (Lyssimachou et al,543 2009a), which could explain the decrease in fatty acid concentra-544 tions.…”