Aberrant Sphingolipid Metabolism in the Human Fallopian Tube with Ectopic Pregnancy

Exosomal microRNAs in tubal fluid may be involved in damage to tubal reproductive function associated with tubal endometriosis

RESEARCH QUESTION

What is the effect of tubal endometriosis on tubal epithelial ultrastructure and is there a differential expression of exosomal microRNAs (miRNAs) in tubal fluid which may affect tubal infertility?

DESIGN

Human fallopian tube epithelium and tubal fluid samples were obtained from patients with and without tubal endometriosis. Scanning electron microscopy and transmission electron microscopy were used to assess ultrastructural changes. Exosomal miRNAs in tubal fluid were extracted for microarray.

RESULTS

Epithelial damage was visualized in the tubal endometriosis group using electron microscopy. The number of organelles decreased (P = 0.0314), and organelle structure was destroyed. A total of 14 differentially expressed exosomal miRNAs were detected in tubal fluid (fold change >2 and P < 0.05). Four miRNAs (miR-1273f, miR-5699-5p, miR-6087 and miR-6747-5p) were validated by quantitative real-time polymerase chain reaction. Bioinformatic analysis showed that most of the target genes participated in embryo transport, regulation of cell communication, anatomical structure morphogenesis and immune system processes.

CONCLUSIONS

Tubal endometriosis results in damage to the tubal epithelial ultrastructure in human specimens and the presence of differentially expressed exosomal miRNAs in tubal liquid. These findings help to clarify the pathogenesis of tubal endometriosis-associated infertility and the mechanisms driving tubal epithelial ultrastructure damage in tubal endometriosis.

Sphingosine 1-Phosphate Activates S1PR3 to Induce a Proinflammatory Phenotype in Human Myometrial Cells

One of the common mechanisms responsible for obstetric complications, affecting millions of women every year, is abnormal uterine contractility. Despite the critical importance of this process for women's health, the mechanisms of uterine contraction regulation remain poorly understood. The initiation of uterine smooth muscle (myometrial) contraction is an inflammatory process, accompanied by upregulation of proinflammatory genes and cytokine release. In this study, we show that sphingolipid metabolism is activated during human labor and that sphingosine 1-phosphate (S1P), the main bioactive sphingolipid, may modify the myometrial proinflammatory phenotype. Our data in both primary and immortalized human myometrial cells show that exogenous S1P induces a proinflammatory gene signature and upregulates the expression of known inflammatory markers of parturition, such as IL8 and COX2. Using expression of IL8 as a readout for S1P activity in myometrial cells, we established that these S1P effects are mediated through the activation of S1P receptor 3 (S1PR3) and downstream activation of ERK1/2 pathways. Inhibition of S1PR3 in human myometrial cells attenuates upregulation of IL8, COX2, and JUNB both at the mRNA and protein levels. Furthermore, activation of S1PR3 with a receptor-specific agonist recapitulated the effects seen after treatment with exogenous S1P. Collectively, these results suggest a signaling pathway activated by S1P in human myometrium during parturition and propose new targets for development of novel therapeutics to alter uterine contractility during management of preterm labor or labor dystocia.

High-throughput quantitation of serological ceramides/dihydroceramides by LC/MS/MS: Pregnancy baseline biomarkers and potential metabolic messengers

Ceramides and dihydroceramides are sphingolipids that present in abundance at the cellular membrane of eukaryotes. Although their metabolic dysregulation has been implicated in many diseases, our knowledge about circulating ceramide changes during the pregnancy remains limited. In this study, we present the development and validation of a high-throughput liquid chromatography-tandem mass spectrometric method for simultaneous quantification of 16 ceramides and 10 dihydroceramides in human serum within 5 min. by using stable isotope-labeled ceramides as internal standards. This method employs a protein precipitation method for high throughput sample preparation, reverse phase isocratic elusion for chromatographic separation, and Multiple Reaction Monitoring for mass spectrometric detection. To qualify for clinical applications, our assay has been validated against the FDA guidelines for Lower Limit of Quantitation (1 nM), linearity (R²>0.99), precision (imprecision<15 %), accuracy (inaccuracy<15 %), extraction recovery (>90 %), stability (>85 %), and carryover (<0.01 %). With enhanced sensitivity and specificity from this method, we have, for the first time, determined the serological levels of ceramides and dihydroceramides to reveal unique temporal gestational patterns. Our approach could have value in providing insights into disorders of pregnancy.

Hypothyroidism modifies differentially the content of lipids and glycogen, lipid receptors, and intraepithelial lymphocytes among oviductal regions of rabbits

Hypothyroidism affects the content of triacylglycerol (TAG), total cholesterol (TC), oxidized lipids, glycogen, and infiltration of immune cells into the ovary and uterus. This study aimed to analyze the impact of hypothyroidism on the lipid content of different regions of the oviduct. Control (n = 6) and hypothyroid (n = 6; 10 mg/kg/day of methimazole in the drinking water for 30 days) adult rabbits were used. In the fimbriae/infundibulum (FIM/INF), ampulla, (AMP), isthmus (IST), and utero-tubal junction (UTJ), the TAG and TC concentrations, presence of oxidized lipid, relative expressions of perilipin A (PLIN A), peroxisome proliferator-activated receptor γ (PPARγ), CAAT/enhancer-binding protein α (C/EBPα), and farnesoid X receptor (FXRα) were analyzed. The content of glycogen and glycans, as well as the infiltration of lymphocytes, were also quantified. In the FIM/INF, hypothyroidism reduced the content of TC, expression of C/EBPα, and presence of glycans while increased the number of intraepithelial lymphocytes. In the AMP and IST-UTJ regions, hypothyroidism increased the content of TAG, oxidized lipids, expression of PPARγ, and glycogen content but decreased the expression of PLIN-A. The FXRα expression in secretory cells of IST-UTJ was higher in the hypothyroid rabbits compared to controls. Additionally, hypothyroidism reduced the C/EBPα expression and the number of intraepithelial lymphocytes in the AMP and IST-UTJ regions, respectively. We demonstrated that the effect of hypothyroidism depends on the oviductal region, possibly associated with different physiological functions specific to each region. These alterations may be related to infertility, tubal disturbances, and ectopic pregnancy observed in hypothyroid women.