|
Comment |
Sphingosine-1-phosphate and its mimetic FTY720 do not protect against radiation-induced ovarian fibrosis in the nonhuman primate. Amargant F et al. (2021) Oocytes are highly radiosensitive, so agents that prevent radiation-induced ovarian follicle destruction are important fertility preservation strategies. A previous study in rhesus macaques demonstrated that ovarian treatment with anti-apoptotic agents, sphingosine-1-phosphate (S1P) and FTY720, its long-acting mimetic, preserved follicles following a single dose of 15 Gy X-ray radiation, and live offspring were obtained from FTY720-treated animals. However, it is unknown whether these anti-apoptotic agents also protected the ovarian stroma from late effects of radiation, including vascular damage and fibrosis. Using ovarian histological sections from this study, we evaluated the vasculature and extracellular matrix in the following cohorts: vehicle + sham irradiation, vehicle + irradiation (OXI), S1P + irradiation (S1P), and FTY720 + irradiation (FTY720). One ovary from each animal was harvested prior to radiation whereas the contralateral ovary was harvested 10 months post-treatment. We assessed vasculature by immunohistochemistry with a PECAM1 antibody, hyaluronan by a hyaluronan binding protein assay, and collagen by picrosirius red and Masson's trichrome staining. Disorganized vessels were observed in the medulla in the OXI and S1P cohorts relative to the sham, but the vasculature in the FTY720 cohort appeared intact, which may partially explain fertoprotection. There were no differences in the hyaluronan matrix among the cohorts, but there was thickening of the tunica albuginea and fibrosis in the OXI cohort relative to the sham, which was not mitigated by either S1P or FTY720 treatment. Thus, the fertoprotective properties of S1P and FTY720 may be limited given their inability to protect the ovarian stroma against the late effects of radiation-induced fibrosis.//////////////////
|
|
Comment |
Effect of sphingosine-1-phosphate on activation of dormant follicles in murine and human ovarian tissue. Pors SE et al. (2020) 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 hours for quantitative PCR analysis, and 12 hours 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 (5x5x1 mm; n = 30; 3 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.//////////////////
Sphingosine-1-phosphate induces COX-2 expression and PGE2 production in human granulosa cells through a S1P1/3-mediated YAP signaling. Cheng JC et al. (2016) Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that can regulate various physiological and pathological processes. The expression of S1P has been detected in human follicular fluid. In addition, two S1P receptors, S1P1 and S1P3, are expressed at a high level in human granulosa cells. Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) production plays a critical role in the regulation of ovulation. However, thus far, the effect of S1P on COX-2 expression and PGE2 production in human granulosa cells remains unknown. In the present study, our results demonstrated that treatment with S1P significantly induced COX-2, but not COX-1, expression and increased PGE2 production in human granulosa cells. The stimulatory effects of S1P on COX-2 expression and PGE2 production were attenuated by treatment with specific antagonist of S1P1 or S1P3 and siRNA-mediated knockdown of S1P1 or S1P3. In addition, the COX-2 expression was induced by S1P1 or S1P3 agonist treatment. Interestingly, treatment with S1P activated YAP signaling via S1P1 and S1P3. Moreover, knockdown of YAP partially attenuated S1P-induced COX-2 expression and PGE2 production. These results provide evidence that S1P induces COX-2 expression and PGE2 production in human granulosa cells through a S1P1/3-mediated YAP signaling pathway.//////////////////
Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles. Hernndez-Coronado CG 2014 et al.
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 17-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 (2.20.3) or atretic (0.20.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 m, 3.0150 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.
/////////////////////////
Targeted anti-apoptosis activity for ovarian protection against chemotherapy-induced ovarian gonadotoxicity. Tan SJ 2014 et al.
Chemotherapy damages the reproductive system by enhancing apoptosis, and evidence suggests that targeted anti-apoptotic therapy may preserve fertility in patients receiving chemotherapy. To investigate the protective effect of sphingosine-1-phosphate (S1P) on chemotherapeutic agent-induced ovarian gonadotoxicity, busulfan-treated female mice were pre-treated with low (0.5?mM) and high (2.0?mM) doses of S1P or vehicle 1?h before busulfan injection. In the S1P groups, each mouse was injected with low-dose S1P in one ovary and high-dose S1P in the contralateral ovary. Four weeks later, the ovaries were removed for histological and biochemical examinations. Caspase 3 immunoreactivity was greater in mice treated with busulfan compared with mice pre-treated with S1P, in which more primordial follicles were observed (P < 0.05). The mRNA level of anti-M?an hormone was higher in mice pre-treated with S1P than those that received busulfan only, indicating a better ovarian function in mice pre-treated with S1P. No difference was observed in the levels of growth differentiation factor-9 among all groups. In conclusion, S1P protects primordial follicles from chemotherapy-induced gonadotoxicity, and may partially preserve ovarian function.
/////////////////////////
Sphinogosine-1-phosphate prevents chemotherapy-induced human primordial follicle death. Li F 2013 et al.
STUDY QUESTION
Can Sphingosine-1-phosphate (S1P), a ceramide-induced death pathway inhibitor, prevent cyclophosphamide (Cy) or doxorubicin (Doxo) induced apoptotic follicle death in human ovarian xenografts?
SUMMARY ANSWER
S1P can block human apoptotic follicle death induced by both drugs, which have differing mechanisms of cytotoxicity.
WHAT IS KNOWN ALREADY
S1P has been shown to decrease the impact of chemotherapy and radiation on germinal vesicle oocytes in animal studies but no human translational data exist.
STUDY DESIGN, SIZE, DURATION
Experimental human ovarian xenografting to test the in vivo protective effect of S1P on primordial follicle survival in the chemotherapy setting. The data were validated by assessing the same protective effect in the ovaries of xenografted mice in parallel.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Xenografted mice were treated with Cy (75 mg/kg), Cy+S1P (200 ?M), Doxo (10 mg/kg), Doxo+S1P or vehicle only (Control). S1P was administered via continuous infusion using a mini-osmotic pump beginning 24 h prior to and ending 72 h post-chemotherapy. Grafts were then recovered and stained with anti-caspase 3 antibody for the detection of apoptosis in primordial follicles. The percentage of apoptotic to total primordial follicles was calculated in each group.
MAIN RESULTS AND THE ROLE OF CHANCE
Both Cy and Doxo resulted in a significant increase in apoptotic follicle death in human ovarian xenografts compared with controls (62.0 ? 3.9% versus 25.7 ? 7.4%, P < 0.01 and 76.7 ? 7.4% versus 25.7 ? 7.4%, P < 0.01, respectively). This chemotherapy-induced apoptotic death was reduced both in the Cy+S1P (32.7 ? 4.4%, P < 0.01) and the Doxo+S1P group (27.1 ? 7.6%, P < 0.01) compared with Cy and Doxo groups, respectively. In the Doxo+S1P and Cy+S1P groups, the percentages of apoptotic follicles were similar to those of vehicle-treated controls (P > 0.05). The findings from the ovaries of the severe combined immunodeficient mice mirrored the findings with human tissue.
LIMITATIONS, REASONS FOR CAUTION
The functionality of the rescued human ovarian follicles needs to be evaluated in future studies though the studies in rodents showed that rescued oocytes can result in healthy offspring. In addition, the impact of S1P on cancer cells should be further studied.
WIDER IMPLICATIONS OF THE FINDINGS
S1P and its future analogs hold promise for preserving fertility by pharmacological means for patients undergoing chemotherapy.
STUDY FUNDING/COMPETING INTEREST(S)
This research is supported by NIH's NICHD and NCI (5R01HD053112-06 and 5R21HD061259-02) and the Flemish Foundation for Scientific Research (FWO-Vlaanderen, grant number FWO G0.065.11N10). The authors have no conflicts of interest to disclose.
/////////////////////////
Sphingosine-1-phosphate inhibits H(2)O(2)-induced granulosa cell apoptosis via the PI3K/Akt signaling pathway. Nakahara T et al. OBJECTIVE: To investigate the protective effect of sphingosine-1-phosphate (S1P) against H(2)O(2)-induced apoptosis in human granulosa cell cultures with freshly harvested granulosa cells. DESIGN: Experimental study. SETTING: Academic medical center for reproductive medicine. PATIENT(S): Cultures of primary granulosa cells isolated from women undergoing in?vitro fertilization (IVF). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Cell apoptosis and Western blot analysis of signaling pathway proteins. RESULT(S): We found that S1P (1 and 10 mM) statistically significantly decreased granulosa cell apoptosis after H(2)O(2) treatment. The decreased cell apoptosis induced by S1P was abolished after treatment with VPC23019, an inhibitor of S1P1 and S1P3 receptors, W146, an inhibitor of S1P1 receptors, and CAY10444, an inhibitor of S1P3 receptors. A Western blot analysis revealed that the level of phospho-Akt increased and peaked at 10 minutes after 10 mM S1P exposure. CONCLUSION(S): Treatment with S1P can inhibit the apoptosis of granulosa cells in response to oxidative stress induced by H(2)O(2). The protective effect of S1P is mediated by activating the PI3K/Akt pathway, and the antiapoptotic effect of S1P is mainly mediated through the S1P1 and S1P3 receptor.
Dose-dependent effect of sphingosine-1-phosphate in mouse oocyte maturation medium on subsequent embryo development. Jee BC 2011 et al.
AIM
To investigate the dose-dependent effect of sphingosine-1-phosphate (S1P) supplementation on meiotic maturation, apoptosis and developmental competence of immature mouse oocytes.
METHODS
Immature oocytes from 5- to 6-week-old BDF1 mice were incubated in maturation medium containing S1P with six different doses (10 nM, 50 nM, 100 nM, 500 nM, 1 ?M, and 2 ?M) for 18-19 h. Fertilization and blastocyst formation was assessed. All blastocysts were stained by anti-caspase antibody.
RESULTS
Treatment with 100 nM, 500 nM and 1 ?M S1P showed significantly higher blastulation rate (66.0, 62.1 and 66.2%, respectively, p < 0.05 when compared with control (40.0%). Blastomere count was similar across six treatment groups, but the percentage of apoptotic blastomere was significantly lower in the 100 nM, 500 nM, and 2 uM S1P-treated groups (5.4, 6.5, and 3.7%, respectively, p < 0.05 when compared with control (10.6%).
CONCLUSION
Considering the blastulation rate together with the apoptotic event in the blastocysts, adding 100 and 500 nM S1P within oocyte maturation medium could be beneficial in the development of immature mouse oocytes.
/////////////////////////
FTY720 and cyclosporin protect ovarian tissue grafted into rabbits. Ying Y 2013 et al.
OBJECTIVE
To determine whether FTY720 combined with CsA has immunomodulatory effects on human ovarian tissue transplanted to the back muscle of rabbits for an 8-week period.
STUDY DESIGN
We selected rabbits as recipients of ovarian xenografts with and without treatment by CsA and FTY720. Ovarian fragments from twelve patients were cut into 2mm?mm, 1-2mm thick pieces and randomly distributed into four groups: Group 1 (FTY720 2mg/kg/d+CsA 3mg/kg/d), Group 2 (FTY720 1mg/kg/d+CsA 3mg/kg/d), Group 3 (FTY720 0.5mg/kg/d+CsA 3mg/kg/d) and Group 4 for control (CsA 3mg/kg/d). FTY720 was started three days before transplantation and was given daily after transplantation. CsA was administrated post-transplantation. All the animals were killed 8 weeks post- transplantation. Levels of serum estrogen (E2), interferon-? (IFN-?) and interleukin-4 (IL-4) were detected by radioimmunoassay and ELISA. Anti-CD31 and anti-Ki-67 antibodies were used to evaluate neo-vascularization in xenografts and proliferation activity of ovarian follicles. Peripheral CD4+/CD8+ T cells were analyzed by flow cytometry.
RESULTS
Combined treatment with cyclosporin A and FTY720 improved graft survival and reduced peripheral CD4+ and CD8+ T cell counts compared to treatment with cyclosporin A alone. Neovascularization took place in the peripheral zone of the xenograft while granulosa cells, positively stained by Ki-67, were found in early-stage follicles and stromal cells in the combined treatment groups.
CONCLUSION
FTY720 in combination with cyclosporin A maintains human ovarian xenografts in these rabbit models.
/////////////////////////
Addition of sphingosine-1-phosphate to human oocyte culture medium decreases embryo fragmentation. Hannoun A 2010 et al.
Apoptosis is implicated in the fragmentation of preimplantation mammalian embryos, yet the extent of this association remains controversial. The aim of this study was to assess the ability of sphingosine-1-phosphate (S1P), a known anti-apoptotic substance, to reduce the fragmentation rate of human preimplantation embryos when added to their culture microenvironment. Mature human oocytes were inseminated using intracytoplasmic sperm injection, incubated for 3 days and evaluated for embryo quality and fragmentation by the same embryologist. Oocytes in the study group were manipulated and cultured in culture medium supplemented with S1P to a 20 micromol/l concentration. A total of 46 patients donated 177 mature oocytes for the study group and 546 oocytes for the control group. The fertilization rate was significantly lower in the S1P-supplemented group (52.4% versus 67.3%; P=0.002) and the proportion of grade I embryos with less than 15% fragmentation was significantly higher in the same group (79.5% versus 53.9%; P<0.0001). Sphingosine-1-phosphate added to the culture medium of human preimplantation embryos is associated with a significantly lower fragmentation rate and hence better quality embryos. The clinical significance of these findings on reproductive outcome remains highly speculative awaiting further studies to translate this improvement in embryo quality into better pregnancy rates.
/////////////////////////
|