Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles

Abstract

The follicle destiny towards ovulation or atresia is multi-factorial in nature and involves outcries, paracrine and endocrine factors that promote cell proliferation and survival (development) or unchain apoptosis as part of the atresia process. In several types of cells, sphingosine-1-phospate (S1P) promotes cellular proliferation and survival, whereas ceramide (CER) triggers cell death, and the S1P/CER ratio may determine the fate of the cell. The aim of present study was to quantify S1P and CER concentrations and their ratio in bovine antral follicles of 8 to 17 mm classified as healthy and atretic antral follicles. Follicles were dissected from cow ovaries collected from a local abattoir. The theca cell layer, the granulosa cells and follicular fluid were separated, and 17β-estradiol (E2) and progesterone (P4) concentrations were measured in the follicular fluid by radioimmunoassay. Based on the E2/P4 ratio, the follicles were classified as healthy (2.2 ± 0.3) or atretic (0.2 ± 0.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 µm, 3.0 × 150 mm column). Results showed that in both follicular compartments, S1P concentrations were higher in healthy antral follicles than in atretic antral follicles (P < 0.05). The concentration of CER in the granulosa cells was higher in atretic antral follicles than in healthy antral follicles, but no differences were observed in the theca cell layer. The S1P/CER ratio in both follicular compartments was also higher in healthy antral follicles. Interestingly, in these follicles, there was a 45-fold greater concentration of S1P than CER in the granulosa cells (P < 0.05), whereas in the theca cell layer, S1P had only a 14-fold greater concentration than CER when compared with atretic antral follicles. These results suggest that S1P plays a role in follicle health, increasing cellular proliferation and survival. In contrast, reduction of S1P and the S1P/CER in the antral follicle could trigger cellular death and atresia.Keywords: bovine, antral follicle, atresia, ceramide, sphingosine-1-phospohate Implications Follicular development involves selection of a follicle apt to grow in response to stimuli (FSH and LH) that induce proliferation and survival of follicular cells so that it reaches ovulation. However, if follicles do not receive these stimuli (reduction in FSH and LH or their receptors), cellular death signals are triggered and the follicle fate will be atresia. Sphingosine-1-phospohate (S1P) induces survival and proliferation of cells, whereas ceramide (CER) is involved in cellular death. The present study reveals that S1P and CER concentrations differ within follicular status suggesting these sphingolipids may participate in follicular health or atresia.Knowledge of signals that control follicular development and atresia may help us to improve follicular development and thus reproductive performance. IntroductionThe development of bovine ovarian follic...

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“…The degeneration of anovulatory subordinate follicles also called follicular atresia, in which apoptosis of granulosa cell is the main mechanism [1,2]. miRNAs which are -22 nt in length non-coding endogenous RNA molecules regulate gene expression in a sequence-dependent manner at posttranscriptional level Ambros [3].…”

miR-183-96-182 Cluster may not Work together in Bovine Ovarian Granulosa Cell Apoptosis

“…Follicle development in cattle undergoes two important precesses, one is ovulation of the preovulatory dominant follicle, and the other is degeneration of anovulatory subordinate follicles Fortune et al 1 The degeneration of anovulatory subordinate follicles also called follicular atresia, in which apoptosis of granulosa cell is the main mechanism. 1,2 miRNAs which are -22nt in length non-coding endogenous RNA molecules regulate gene expression in a sequence-dependent manner at posttranscriptional level Ambros. 3 How these small molecules posttranscriptionally regulate apoptosis process and finally the follicles…”

La esfingosina 1-fosfato (S1P) como mediador de los efectos biológicos de la hormona folículo-estimulante (FSH) en células de la granulosa de bovino

“…La S1P es una molécula bioactiva que regula la proliferación, sobrevivencia y esteroidogénesis de manera intracelular y extracelular en diversos tejidos como células endoteliales, pulmonares, ováricas entre otras (Obinata & Hla, 2019). Estudios recientes en nuestro laboratorio mostraron que las CG de folículos sanos de bovino contienen tres veces más S1P que los folículos atrésicos (Hernandez-Coronado et al, 2015).…”

“…Se colocó la mezcla sobre una cámara de Neubauer, se contó el número de células no teñidas sobre 5 cuadrantes en cada una de las cámaras. Finalmente, el número de células totales viables se obtuvieron utilizando la siguiente fórmula: Promedio de ambas cámaras x 10,000 x 5 cuadrantes x dilución de la mezcla (Hernandez-Coronado et al, 2015),…”

“…Dentro de los principales efectos que desencadena FSH en CG se encuentran la proliferación, sobrevivencia y síntesis de hormonas esteroideas (Hunzicker-Dunn et al, 2012). Además de las gonadotropinas, otras hormonas y factores de crecimiento, los esfingolípidos han emergido como moléculas señalizadoras durante el desarrollo de folículos antrales (Hernandez-Coronado et al, 2015, 2016.…”