Our results demonstrate the existence of an endometrial microbiota that is highly stable during the acquisition of endometrial receptivity. However, pathological modification of its profile is associated with poor reproductive outcomes for in vitro fertilization patients. This finding adds a novel microbiological dimension to the reproductive process.

The monthly remodeling, shedding, and regeneration of the endometrium defining the human menstrual cycle is driven by gene expression changes in the underlying tissue hierarchy. Significant heterogeneity exists among cell types in the endometrium, such that multiple cell types vary dramatically in state through a monthly cycle and undergo various forms of differentiation at rapid rates. Histologic analysis and whole-tissue transcriptomic profiling have defined a specific molecular state as the optimal timing of the window of implantation (WOI) for in vitro fertilization transfer.This single-cell transcriptomic analysis aimed to characterize the transcriptomic transformation of human endometrium at single-cell resolution across the menstrual cycle, including at the WOI. Endometrial biopsies were collected from 19 healthy ovum donors between 4 and 27 days following menses, and single cells were captured and complementary DNA was generated using Fluidigm C1 medium chips. Six cell types were identified across the menstrual cycle: stromal fibroblast, endothelium, macrophage, lymphocyte, ciliated epithelium, and unciliated epithelium.Endometrial transformation was analyzed by within-cell type t-SNE using whole-transcriptome data from unciliated epithelia and stromal fibroblasts, the 2 major contributing cell types to endometrial transformation. This revealed 4 major, time-associated phases of both cell types. Among unciliated epithelia, single-cell gene dynamics were relatively continuous across phases 1 to 3 until an abrupt activation of genes consistently reported in whole-tissue transcriptomic data sets as overexpressed in the WOI marked entrance into phase 4. Among stromal fibroblasts, the WOI was characterized by widespread decidualization that became gradually upregulated through phase progression. Likewise, the WOI closed with more gradual transition dynamics in both cell types.The traditional definition of endometrial phases, consisting of the proliferative and secretory phases, correlated with the 4 phases identified here through single-cell analysis. Cell-cycling was elevated in phases 1 and 2 and ceased in later phases, suggesting the transition from proliferative to secretory occurred between phase 2 and 3. At the transcriptomic level, proliferative endometrium can be divided into 2 distinct phases with unique transcriptomic signatures.This study involved the systematic characterization of the human endometrium across the menstrual cycle through dynamic gene expression mapping. The results demonstrate that ciliated epithelium are a transcriptomically distinct endometrial cell type that are highly prevalent in the human endometrium and constantly changing in abundance across the cycle. This study likewise demonstrated an abrupt and strong transcriptomic activation in unciliated epithelia and a gradual activation in stromal fibroblasts to define the opening of the WOI, indicating a potential diagnostic target for more precise in vitro fertilization and embryo transfer.

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During embryo implantation, the blastocyst interacts with and regulates the endometrium, and endometrial fluid secreted by the endometrial epithelium nurtures the embryo. Here, we propose that maternal microRNAs (miRNAs) might act as transcriptomic modifier of the pre-implantation embryo. Microarray profiling revealed that six of 27 specific, maternal miRNAs were differentially expressed in the human endometrial epithelium during the window of implantation -a brief phase of endometrial receptivity to the blastocyst -and were released into the endometrial fluid. Further investigation revealed that hsa-miR-30d, the expression levels of which were most significantly upregulated, was secreted as an exosome-associated molecule. Exosome-associated and free hsa-miR-30d was internalized by mouse embryos via the trophectoderm, resulting in an indirect overexpression of genes encoding for certain molecules involved in the murine embryonic adhesion phenomenon -Itgb3, Itga7 and Cdh5. Indeed, this finding was supported by evidence in vitro: treating murine embryos with miR-30d resulted in a notable increase in embryo adhesion. Our results suggest a model in which maternal endometrial miRNAs act as transcriptomic modifiers of the preimplantation embryo.

The molecular microbiology method describe herein is a fast and inexpensive diagnostic tool that allows for the identification of culturable and nonculturable endometrial pathogens associated with chronic endometritis. The results obtained were similar to all 3 classic diagnostic methods together with a degree of concordance of 76.92% providing an opportunity to improve the clinical management of infertile patients with a risk of experiencing this ghost endometrial pathology.

DNA double-strand breaks (DSB) can arise during DNA replication, or after exposure to DNA-damaging agents, and their correct repair is fundamental for cell survival and genomic stability. Here, we show that the Smc5-Smc6 complex is recruited to DSBs de novo to support their repair by homologous recombination between sister chromatids. In addition, we demonstrate that Smc5-Smc6 is necessary to suppress gross chromosomal rearrangements. Our findings show that the Smc5-Smc6 complex is essential for genome stability as it promotes repair of DSBs by error-free sister-chromatid recombination (SCR), thereby suppressing inappropriate non-sister recombination events.

(Abstracted from Am J Obstet Gynecol 2016;215(6):684–703) In 2002, the vaginal microbiota was first identified using molecular methods that allowed detection of nonculturable bacteria. Alterations in vaginal microbiota could have clinical implications for reproductive and obstetric processes.

In this study we analyze the participation of the PKC1-MAPK cell integrity pathway in cellular responses to oxidative stress in Saccharomyces cerevisiae. Evidence is presented demonstrating that only Pkc1 and the upstream elements of the cell integrity pathway are essential for cell survival upon treatment with two oxidizing agents, diamide and hydrogen peroxide. Mtl1 is characterized for the first time as a cell-wall sensor of oxidative stress. We also show that the actin cytoskeleton is a cellular target for oxidative stress. Both diamide and hydrogen peroxide provoke a marked depolarization of the actin cytoskeleton, being Mtl1, Rom2 and Pkc1 functions all required to restore the correct actin organization. Diamide induces the formation of disulfide bonds in newly secreted cell-wall proteins. This mainly provokes structural changes in the cell outer layer, which activate the PKC1-MAPK pathway and hence the protein kinase Slt2. Our results led us to the conclusion that Pkc1 activity is required to overcome the effects of oxidative stress by: (i) enhancing the machinery required to repair the altered cell wall and (ii) restoring actin cytoskeleton polarity by promoting actin cable formation.