Activation of multidrug efflux transporter activity at fertilization in sea urchin embryos (Strongylocentrotus purpuratus).

Hopkins Marine Station, Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA.
Developmental Biology (Impact Factor: 3.64). 01/2005; 276(2):452-62. DOI: 10.1016/j.ydbio.2004.09.013
Source: PubMed

ABSTRACT This study presents functional and molecular evidence for acquisition of multidrug transporter-mediated efflux activity as a consequence of fertilization in the sea urchin. Sea urchin eggs and embryos express low levels of efflux transporter genes with homology to the multidrug resistance associated protein (mrp) and permeability glycoprotein (p-gp) families of ABC transporters. The corresponding efflux activity is low in unfertilized eggs but is dramatically upregulated within 25 min of fertilization; the expression of this activity does not involve de novo gene expression and is insensitive to inhibitors of transcription and translation indicating activation of pre-existing transporter protein. Our study, using specific inhibitors of efflux transporters, indicates that the major activity is from one or more mrp-like transporters. The expression of activity at fertilization requires microfilaments, suggesting that the transporters are in vesicles and moved to the surface after fertilization. Pharmacological inhibition of mrp-mediated efflux activity with MK571 sensitizes embryos to the toxic compound vinblastine, confirming that one role for the efflux transport activity is embryo protection from xenobiotics. In addition, inhibition of mrp activity with MK571 alone retards mitosis indicating that mrp-like activity may also be required for early cell divisions.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: One quarter of eukaryotic genes encode membrane proteins. These include nearly 1,000 transporters that translocate nutrients, signaling molecules, and xenobiotics across membranes. While it is well appreciated that membrane transport is critical for development, the specific roles of many transporters have remained cryptic, in part because of their abundance and the diversity of their substrates. Multidrug resistance ATP-binding cassette (ABC) efflux transporters are one example of cryptic mem-brane proteins. Although most organisms utilize these ABC transporters during embryonic development, many of these transporters have broad substrate specificity, and their developmental functions remain incompletely understood. Here, we review advances in our understanding of ABC transporters in sea urchin embryos, and methods developed to spatially and temporally map these proteins. These studies reveal that multifunctional transporters are required for signaling, homeostasis, and protection of the embryo, and shed light on how they are integrated into ancestral developmental pathways recapitulated in disease. ''[Multidrug resistance transporters] can be thought of as being more like Swiss army knives than vegetable peelers, with functions dictated by the cellular context in which they are expressed.''
    Molecular Reproduction and Development 08/2014; 81(9). · 2.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Usage of bisphenol A (BPA) in production of polycarbonate plastics has resulted in global distribution of BPA in the environment. These high concentrations cause numerous negative effects to the aquatic biota, among which the most known is the induction of endocrine disruption. The focus of this research was to determine the effects of two experimentally determined concentrations of BPA (100 nM and 4 μM) on cellular detoxification mechanisms during the embryonic development (2-cell, pluteus) of the rocky sea urchin (Paracentrotus lividus), primarily the potential involvement of multidrug efflux transport in the BPA intercellular efflux. The results of transport assay, measurements of the intracellular BPA and gene expression surveys, for the first time indicate the importance of P-glycoprotein (P-gp/ABCB1) in defense against BPA. Cytotoxic effects of BPA, validated by the immunohistochemistry (IHC) and the transmission electron microscopy (TEM), induced the aberrant karyokinesis, and consequently, the impairment of embryo development through the first cell division and retardation.
    Aquatic Toxicology 11/2014; 156:21–29. · 3.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nanoplastic debris, resulted from run-off and weathering breakdown of macro and microplastics, represent an emerging concern for marine ecosystems. The aim of the present study was to investigate disposition and toxicity of polystyrene nanoparticles (PS NPs) in early development of sea urchin embryos Paracentrotus lividus. NPs with two different surface charges where chosen, carboxylated (PS-COOH) and amine (PS-NH2) polystyrene, the latter being a less common variant, known to induce cell death in several in vitro cell systems. NPs stability in natural seawater (NSW) was measured while disposition and embryotoxicity were monitored within 48 h post-fertilization (hpf). Modulation of genes involved in cellular stress response (cas8, 14-3-3ε, p-38 MAPK, Abcb1, Abcc5) was investigated. PS-COOH form micro-aggregates (PDI > 0.4) in NSW, while PS-NH2 result better dispersed (89 nm ± 2 nm) initially, though they also aggregated partially with time. Their respectively anionic and cationic nature was confirmed by zeta potential measurements. No embryotoxicity was observed for PS-COOH up to 50 µg mL-1 while PS-NH2 caused severe developmental defects (EC50 3.85 µg mL-1 -24 hpf and EC50 2.61 µg mL-1 -48 hpf). PS-COOH accumulated inside embryo's digestive trait while PS-NH2 were more dispersed. Abcb1 gene resulted up-regulated at 48 hpf by PS-COOH while PS-NH2 induced cas8 gene at 24 hpf, suggesting an apoptotic pathway. In line with the results obtained with the same PS NPs in several human cell lines, also in sea urchin embryos, differences in surface charges and aggregation in sea water strongly affect their embryotoxicity.
    Environmental Science and Technology 09/2014; · 5.48 Impact Factor

Full-text (2 Sources)

Available from
May 21, 2014