Homosalate and ERK Knockdown in the Modulation of Aurelia coerulea Metamorphosis by Regulating the PI3K Pathway and ERK Pathway

Abstract

Metamorphosis control is pivotal in preventing the outbreak of jellyfish, and it is often studied using common model organisms. The widespread use of the ultraviolet blocking agent homosalate in cosmetics poses a threat to marine ecosystems. Although the impact of homosalate on marine organisms has been extensively examined, there is a notable absence of research on its effects on jellyfish metamorphosis and the underlying mechanisms, warranting further investigation. In this study, we first established a study model by using 5-methoxy-2-methylindole to induce Aurelia coerulea metamorphosis, and selected homosalate as a PI3K agonist and an ERK agonist, while we used YS-49 as a specific PI3K agonist, as well as ERK knockdown, to observe their effect on the metamorphosis of Aurelia coerulea. The results showed that an Aurelia coerulea metamorphosis model was established successfully, and the PI3K agonist homosalate, YS-49, and the knockdown of ERK molecules could significantly delay the metamorphosis development of Aurelia coerulea. We propose that activating PI3K/Akt and inhibiting the ERK pathway are involved in the delayed development of Aurelia coerulea, which provides a new strategy for the prevention and control of jellyfish blooms.

Keywords: Aurelia coerulea; ERK pathway; PI3K pathway; homosalate; metamorphosis.

Figure 1

Metamorphosis of Aurelia coerulea polyps induced by 5–methoxy–2–methylindole and low temperature.

Figure 2

Homosalate inhibits the metamorphosis of Aurelia coerulea polyps. (A) The whole process of metamorphosis of Aurelia coerulea polyps under the somatotype microscope (scale bar: 1 mm). (B–E) The effect of 1 μM and 100 nM homosalate on the process of Aurelia coerulea metamorphosis in polyps, early strobila, late strobila and ephyra, respectively (n = 30, ^ns no significance, * p < 0.05, ** p < 0.01, *** p < 0.001).

Figure 3

YS-49 inhibits the metamorphosis of Aurelia coerulea polyps. (A–D) The effect of 1 μM, 3 μM, 10 μM, 30 μM, and 50 μM YS-49 solution on the process of Aurelia coerulea metamorphosis in polyps, early strobila, late strobila, and ephyra, respectively (n = 30, ^ns no significance* p < 0.05, ** p < 0.01, *** p < 0.001).

Figure 4

Knocking down ERK inhibits the metamorphosis process of Aurelia coerulea polyps. (A–C) RT-qPCR verification result of ERK knockdown. (D–F) The effect of knocking down ERK (evm.model.CTG_2.65) on the process of Aurelia coerulea metamorphosis in early strobila, late strobila, and ephyra, respectively (n = 30, ^ns no significance, * p < 0.05, *** p < 0.001).

Figure 5

Signal pathway map of metamorphosis of Aurelia coerulea polyps (scale bar: 1 mm. → means function, + means activate, − means prohibit).