Fig. 4
From: Shared regulatory function of non-genomic thyroid hormone signaling in echinoderm skeletogenesis
Inhibitors of MAPK phosphorylation and integrin binding inhibit the effect of thyroid hormones on skeletogenesis in sea urchin, brittle star, and sea star gastrulae and larvae. Larvae were exposed to the thyroid hormones, rT3, T3, and T4 (10–7 M), RGD peptide (RGD; 10–7 M) or PD98059 (PD; 5 × 10–7 M). A Sea urchin gastrulae. Thyroid hormones, including T4 and T3, accelerate initiation of skeletogenesis in sea urchin gastrulae relative to the control (n = 20, F (7152) = 9.20; Tukey’s HSD, p < 0.00001, T4: 95% CI [2.06-fold, 4.16-fold], T3: 95% CI [1.57-fold, 2.62-fold]). RGD peptide and PD98059 inhibit the effects of T4 on skeletogenesis (Tukey’s HSD, p < 0.00001). Data reproduced from [106]. B Sea star gastrulae. THs were not found to induce skeletogenesis in sea star gastrulae (n = 20, ANOVA not possible, all groups identical; p = 1.00). Sea star gastrulae do not contain the cell type necessary for skeletogenesis. C Brittle star gastrulae. Thyroid hormones, including T4 and T3, accelerate initiation of skeletogenesis in Brittle star gastrulae (n = 20, F (7152) = 12.45; p < 0.00001; Tukey’s HSD, T4: 95% CI [1.75-fold, 2.69-fold], T3: 95% CI [1.08-fold, 2.03-fold]). RGD peptide (RGD) and PD98059 (PD) partially inhibit the effects of THs on skeletogenesis (Tukey’s HSD, p < 0.0001). D Sea urchin pluteus larva. Thyroid hormones accelerate juvenile skeletogenesis (n = 12, F (10,121) = 20.88, p < 0.00001), even in the presence of RGD peptide, or PD98059 (p = 0.0023, 0.019). A higher dosage of RGD peptide/PD98059 was previously found to inhibit skeletogenesis (Taylor 2021). Data reproduced from [106]. E Sea star bipinnaria larva. Thyroid hormones accelerate, including T4 and T3, juvenile skeletogenesis (n = 6, F (7,40) = 36.25, p < 0.00001). The effect of thyroid hormones is inhibited by PD9809 and RGD peptide (Tukey’s HSD, p < 0.00001). F Ophiopluteus larva. Thyroid hormones (T4) accelerate juvenile skeletogenesis (n = 12, F (3,44) = 24.22; Tukey’s HSD p < 0.00001). This effect is partially inhibited by PD98059 (p = 0.0163). The effect of RGD peptide on skeletogenesis was not tested in late-stage O. aculeata. Asterisk indicates significant difference from the control