Aerophobin-1 from the Marine Sponge Aplysina  aerophoba Modulates Osteogenesis in Zebrafish Larvae

Abstract

Longer life expectancy has led to an increase in efforts directed to the discovery of new healing agents for disorders related to aging, such as bone diseases. Harboring an incredible variety of bioactive metabolites, marine organisms are standing out as fruitful sources also in this therapeutic field. On the other hand, the in vivo zebrafish model has proven to be an excellent low-cost screening platform for the fast identification of molecules able to regulate bone development. By using zebrafish larvae as a mineralization model, we have thus evaluated the effects of the crude acetonic extract from the marine sponge Aplysina aerophoba and its bromotyrosine components on bone development. Obtained results led to the selection of aerophobin-1 (1) as a promising candidate for applications in regenerative medicine, paving the way for the development of a novel therapeutic option in osteoporosis treatment.

Keywords: bromotyrosine; drug discovery; marine natural products; osteogenesis; zebrafish.

Figure 1

Effect of different dilutions of A. aerophoba crude extract on (A) zebrafish embryos/larvae viability and (B) mineralization rate of the vertebral bodies. (C) Mineralized vertebrae visualized by alizarine red staining (purple) together with unmodified cartilage structures (blue) in control (0 concentration) and treated (30 µg/L sponge extract) larvae. Significant differences were evaluated by using the Student’s t-test (α = 0.05; * p ≤ 0.05, ** p ≤ 0.01).

Figure 2

Chemical structures of bromotyrosine alkaloids isolated from A. aerophoba.

Figure 3

Viability of embryos treated with different concentrations (from 1 pM to 100 µM) of the eight compounds (1–8) isolated from A. aerophoba. Bars indicate the number of live embryos at 5 dpf. Significant differences were evaluated by using the Student’s t-test (α = 0.05; * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001).

Figure 4

Mineralization rate in embryos exposed to compounds 1–5 and 7, evaluated as number of mineralized vertebrae at 5 dpf normalized for embryo length (NV/L). Significant differences were evaluated by using the Student’s t-test (α = 0.05; * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001).