Typical 2-Cys Peroxiredoxins as a Defense Mechanism against Metal-Induced Oxidative Stress in the Solitary Ascidian Ciona robusta

Abstract

Typical 2-Cys peroxiredoxins (2-Cys Prdxs) are proteins with antioxidant properties belonging to the thioredoxin peroxidase family. With their peroxidase activity, they contribute to the homeostatic control of reactive oxygen species (ROS) and, therefore, participate in various physiological functions, such as cell proliferation, differentiation, and apoptosis. Although Prdxs have been shown to be potential biomarkers for monitoring aquatic environments, minimal scientific attention has been devoted to describing their molecular architecture and function in marine invertebrates. Our study aims to clarify the protective role against stress induced by exposure to metals (Cu, Zn, and Cd) of three Prdxs (Prdx2, Prdx3, and Prdx4) in the solitary ascidian Ciona robusta, an invertebrate chordate. Here, we report a detailed pre- and post-translational regulation of the three Prdx isoforms. Data on intestinal mRNA expression, provided by qRT-PCR analyses, show a generalized increase for Prdx2, -3, and -4, which is correlated to metal accumulation. Furthermore, the increase in tissue enzyme activity observed after Zn exposure is slower than that observed with Cu and Cd. The obtained results increase our knowledge of the evolution of anti-stress proteins in invertebrates and emphasize the importance of the synthesis of Prdxs as an efficient way to face adverse environmental conditions.

Metallothionein Expression as a Physiological Response against Metal Toxicity in the Striped Rockcod Trematomus hansoni

“…[ 46 ]. We have frequently emphasized this characteristic in species that are exposed to stressogenic environments but that are not experiencing acute stress [ 47 , 48 ], such as Antarctic fish [ 49 , 50 , 51 ], which enables the tissues to react to acute stress very quickly when it suddenly arises. The occurrence of stress granulates in the liver of T. hansoni experimentally exposed to metals is a possible explanation for our results.…”

Metallothionein Expression as Physiological Response Against Metal Toxicity in the Striped Rockcod <em>Trematomus hansoni</em>

“…This control seems to be based on the formation of stress granules (SGs), cytoplasmic foci in which the messengers can be stored, undergoing future translation [34]. This condition is a common feature in organisms that live in stressogenic conditions, but without acute stress [35][36][37][38][39], allowing an extremely rapid response by the tissues toward the sudden onset of acute stress. This can easily occur in liver of T. hansoni experimentally exposed to metals.…”

Metallothionein Expression as Physiological Response Against Metal Toxicity in the Striped Rockcod <em>Trematomus hansoni</em>

“…This control seems to be based on the formation of stress granules (SGs), cytoplasmic foci in which the messengers can be stored, undergoing future translation [37]. This condition is a common feature in organisms that live in stressogenic conditions, but without acute stress [38][39][40][41][42], allowing an extremely rapid response by the tissues toward the sudden onset of acute stress. This can easily occur in the liver of T. hansoni experimentally exposed to metals.…”