Antioxidant Responses Induced by Short-Term Activity–Estivation–Arousal Cycle in Pomacea canaliculata

Abstract

Long-term estivation (45 days) in the apple snail Pomacea canaliculata induces an increase of non-enzymatic antioxidants, such as uric acid and reduced glutathione (GSH), which constitutes an alternative to the adaptive physiological strategy of preparation for oxidative stress (POS). Here, we studied markers of oxidative stress damage, uric acid levels, and non-enzymatic antioxidant capacity, enzymatic antioxidant defenses, such as superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST), and transcription factors expression [forkhead box protein O (FOXO), hypoxia-inducible factor-1 alpha (HIF1α), and nuclear factor erythroid 2-related factor 2 (Nrf2)] in control active animals, 7-day estivating and aroused snails, in digestive gland, gill, and lung tissue samples. In the digestive gland, SOD and CAT activities significantly increased after estivation and decreased during arousal. Meanwhile, GST activity decreased significantly during the activity–estivation–arousal cycle. Gill CAT activity increased significantly at 7 days of estivation, and it decreased during arousal. In the lung, the CAT activity level increased significantly during the cycle. FOXO upregulation was observed in the studied tissues, decreasing its expression only in the gill of aroused animals during the cycle. HIF1α and Nrf2 transcription factors decreased their expression during estivation in the gill, while in the lung and the digestive gland, both transcription factors did not show significant changes. Our results showed that the short-term estivation induced oxidative stress in different tissues of P. canaliculata thereby increasing overall antioxidant enzymes activity and highlighting the role of FOXO regulation as a possible underlying mechanism of the POS strategy.

Short-Term Estivation and Hibernation Induce Changes in the Blood and Circulating Hemocytes of the Apple Snail Pomacea canaliculata

“…The apple snail P. canaliculata shows notable adaptations, such as the possibility of estivating and hibernating to tolerate seasonal activity–dormancy–arousal cycles [ 10 ]. In this way, the POS strategy is used by this species to avoid damage to vital cellular components by free radicals in tissues [ 13 , 15 ]. Until now, in those gastropods where the use of the POS strategy has been described (i.e., reported ten species, [ 11 , 12 , 13 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]), the experimental tests have been carried out on tissue extracts, not taking into account the changes occurring in compounds and cells from the blood.…”

“…Thus, animals comprised five groups: (1) control (active), (2) estivation (est), (3) arousal-est, (4) hibernation (hib), and (5) arousal-hib. Our laboratory has previously characterized the experimental inductions of activity–dormancy–arousal cycles [ 11 , 12 , 13 , 21 ].…”

“…Whatever the stressful condition that is going through, ampullariids may augment endogenous antioxidant defenses, anticipating the expected respiratory burst during reoxygenation upon reactivation [ 11 , 12 , 13 ]. The described pattern, namely “Preparation for Oxidative Stress (POS)”, occurs in more than 100 species distributed among nine phyla [ 14 ].…”

“…Previous laboratory studies have shown that estivating or hibernating apple snails adjust to the pattern of the POS strategy [ 11 , 12 , 13 , 21 ]. In experimentally induced estivation and hibernation periods of 45 days, tissue antioxidants such as uric acid and glutathione (GSH) increase and act as a protective mechanism [ 11 , 12 ].…”

“…Under short-term estivation (7 days), however, enzymatic antioxidant activities of catalase (CAT) and superoxide dismutase (SOD) augment in several tissues while that of glutathione S-transferase (GST) diminishes in the digestive gland. Moreover, the enzymatic response seems mediated by the REDOX-sensitive transcription factor forkhead box protein O 3 (FOXO3) because its expression increases in tissues exposed to an activity–estivation–arousal cycle, unlike hypoxia-inducible factor-1 alpha (HIF1α) and nuclear factor erythroid 2-related factor 2 (Nrf2), two other REDOX-sensitive transcription factors, which show decreased expression during the cycle [ 13 ]. Therefore, P. canaliculata apparently triggers an enzymatic defense response that may change to a non-enzymatic defense response.…”