Characterization of functional activity of ABCB1 and ABCC1 proteins in eggs and embryonic cells of the sea urchin Echinometra lucunter

Abstract

ABC transporter (ATP-binding-cassette transporter) proteins have been strongly associated with the phenomenon of multidrug resistance in cancer cells. Furthermore, their physiological expression has been studied in many organisms, including bacteria, fungi, plants and vertebrate or invertebrate animals. Their widespread expression through the evolution demonstrates their relevance to the survival of living things. In the present study, we characterized the functional activity of ABCB1 and ABCC1 proteins in gametes and embryonic cells of the sea urchin Echinometra lucunter. The ABC transporter proteins' functional activity was up-regulated post-fertilization. Eggs and spermatozoa of E. lucunter accumulated more C-AM (calcein acetoxymethyl ester), a fluorescent substrate of ABCB1 and ABCC1 proteins, than embryonic cells. Verapamil, reversin 205 and indomethacin were able to increase C-AM influx in eggs and embryos. However, verapamil and reversin 205 were more efficient than indomethacin, suggesting a predominance of ABCB1 protein over ABCC1 protein activity. Multidrug resistance modulating agents, at the concentration range that inhibited ABC transporter proteins, did not block the embryonic development until blastula stage. However, inhibition of ABCB1-mediated efflux by reversin 205 circumvented resistance of embryos to the antimitotic vinca alkaloid vinblastine. Embryonic development was more efficiently blocked when colchicine was previously added to eggs than to embryos 5 min after fertilization. This set of results suggests that these proteins act as a fundamental biochemical barrier conferring a protective physiological role against toxic xenobiotics in E. lucunter embryos.

ATP‐binding cassette transporters protect sea urchin gametes and embryonic cells against the harmful effects of ultraviolet light

“…). These findings are in agreement with our previous report that ABC‐transporter activity is highest in zygotes, followed by eggs, then spermatozoa (De Souza et al, ). Together, these data present a differential role of ABC transporters in establishing UVB resistance between sea urchin gametes and zygotes.…”

Extracellular Ca2+ influx is crucial for the early embryonic development of the sea urchin Echinometra lucunter

“…Like other Ca 2+ channel blockers, VP is an ABCB1 protein (also known as P‐glycoprotein) substrate. ABCB1 protein is fully active 20 min after fertilization in E. lucunter embryonic cells (De Souza et al, ). To investigate whether the loss of the inhibitory effect of VP on the embryonic development, 50 min postfertilization, was due to activity of ABCB1 protein, embryos were incubated with reversin 205 (REV, 5 µM) and treated or not with VP (100 µM) 20–50 min postfertilization.…”

Mitochondrial permeability transition pore (MPTP) desensitization increases sea urchin spermatozoa fertilization rate

“…The inconsistent results can be attributed to calcein self‐quenching, which may be related to several reasons since the presence of ABC transporters activity (Silva‐Neta et al, ) to the small cell size or the small amount of cytoplasm compared to the large mitochondrion in the spermatozoa. Calcein‐AM is an ABC transporters substrate and CsA blocks the activity of several ABC proteins, which increases calcein concentration inside the cell (Hait et al, ; Tiberghien and Loor, ; Marques‐Santos et al, ; Hamdoun et al, ; De Souza et al, ; Silva‐Neta et al, ). Additionally, Hamann et al () demonstrated that calcein exhibits a strong self‐quenching that is responsible for the reduction in the fluorescence level according to the cell size.…”