Effect of sphingosine-1-phosphate on activation of dormant follicles in murine and human ovarian tissue

Abstract

In vitro activation of resting ovarian follicles, with the use of mechanical stress and/or pharmacological compounds, is an emerging and novel approach for infertility treatment. The aim of this study was to assess the sphingolipid, sphingosine-1-phosphate (S1P), as a potential in vitro activation agent in murine and human ovarian tissues and isolated follicles. Juvenile murine ovaries and donated human ovarian tissues, from 10 women undergoing ovarian tissue cryopreservation for fertility preservation, were incubated with or without 12 μM S1P for 3 h for quantitative PCR analysis, and 12 h for xenotransplantation or culture studies. Gene expression analyses were performed for genes downstream of the Hippo signaling pathway. Murine ovaries and isolated murine and human preantral follicles showed significantly increased mRNA expression levels of Ccn2/CCN2 following S1P treatment compared to controls. This increase was shown to be specific for the Hippo signaling pathway and for the S1P2 receptor, as co-treatment with Hippo-inhibitor, verteporfin and S1PR2 antagonist, JTE-013, reduced the S1P-induced Ccn2 gene expression in murine ovaries. Histological evaluation of human cortical tissues (5 × 5 × 1 mm; n = 30; three pieces per patient) xenografted for 6 weeks and juvenile murine ovaries cultured for 4 days (n = 9) or allografted for 2 weeks (n = 48) showed no differences in the distribution of resting or growing follicles in S1P-treated ovarian tissues compared to controls. Collectively, S1P increased Ccn2/CCN2 gene expression in isolated preantral follicles and ovarian tissue from mice and human, but it did not promote follicle activation or growth in vivo. Thus, S1P does not appear to be a potent in vitro activation agent under these experimental conditions.

Ovarian Fragmentation and AKT Stimulation for Expansion of Fertile Lifespan

“…In contrast, a recent study revealed that S1P treatment could neither activate the primordial follicle nor induce the follicle growth in both mice and human ovaries though the CCN2 gene expression was increased. However, the authors admitted that the longer renewal interval of S1P as compared to one in the study of Cheng et al (24 vs. 12 h, respectively) could affect the result because the half-life of S1P is as short as 15 min (51). Genetic studies illustrated the importance of Hippo signaling pathway in regulating folliculogenesis.…”

Ovarian tissue damage after grafting: systematic review of strategies to improve follicle outcomes

“…Two of the 3 studies in rodents showed higher follicle survival rates at 15 and 28 days post-transplantation. Investigations into the impact of NAC in human xenografts did not reveal any clear positive effect on follicle outcomes because, while suggesting a decrease in apoptosis, they did not result in a significant upturn in the follicle count after grafting (Olesen et al, 2020). The same was true of vitamin E. Indeed, althouh an increased follicle count was detected in a murine model (Nugent et al, 1998), experiments using non-human primate models (Scalercio et al, 2016) Melatonin was tested in rodents, either by administration to the host for a month, yielding an increase in follicle survival (Hemadi et al, 2011), or by in vitro ovarian tissue pretreatment, which made no difference to follicle outcomes (Hemadi et al, 2009).…”

“…When assessing oxidative stress modulation by use of NAC, 2 out of 3 studies detected a decrease in MDA levels (Mahamoodi et al, 2015; Tuncer et al, 2018), while one showed an increase in antioxidant activity by enhanced action of scavengers like CAT and SOD1 (Olesen et al, 2020). Looking at potential impacts on neovascularization, some investigations into NAC revealed findings to the contrary, namely a fall in VEGF expression (Tuncer et al, 2018) and drop in vessel density (Olesen et al, 2020).…”

“…When assessing oxidative stress modulation by use of NAC, 2 out of 3 studies detected a decrease in MDA levels (Mahamoodi et al, 2015; Tuncer et al, 2018), while one showed an increase in antioxidant activity by enhanced action of scavengers like CAT and SOD1 (Olesen et al, 2020). Looking at potential impacts on neovascularization, some investigations into NAC revealed findings to the contrary, namely a fall in VEGF expression (Tuncer et al, 2018) and drop in vessel density (Olesen et al, 2020). A possible explanation could be that the anti-inflammatory and antioxidant effects of NAC may diminish the tissue response to neoangiogenesis by decreasing expression of proangiogenic growth factors like VEGF (Licks et al, 2012;Moazzen et al, 2014).…”

New Insights into the Role of Sphingolipid Metabolism in Melanoma

“…This pathway has been shown to modulate Wnt and TGF-β signalling and confer pro-invasive properties in melanoma [ 116 ]. Strikingly, multiple studies have identified S1P as an activator of YAP through S1P2 signalling [ 117 , 118 , 119 ]. Similarly, a recent study demonstrated that inhibition of SphK1 using the PF-543 inhibitor could inhibit TGFβ-induced activation of YAP [ 120 ].…”