A positive ReceptivaDx result for BCL6 does not correlate with abnormal ERA results or decreased expression of receptivity-associated markers: two sides of the endometrial receptivity coin in fertility evaluation and treatment.

OBJECTIVE: To investigate if a positive result on ReceptivaDx for evaluation of B-cell lymphoma 6 (BCL6), a proposed marker of progesterone resistance associated with impaired uterine receptivity, correlates with a suboptimal profile of receptivity-associated markers in the window of implantation using the endometrial receptivity array and single-nucleus transcriptomic analysis DESIGN: Retrospective clinical cohort study; pilot study of single-nucleus RNA sequencing of prospectively collected window of implantation endometrium undergoing ReceptivaDx BCL6 evaluation SETTING: Academic center SUBJECTS: Patients with infertility who underwent endometrial biopsy for concurrent endometrial receptivity array analysis (ERA®; Igenomix) and BCL6 immunostaining (ReceptivaDx™; Cicero Diagnostics, Inc.) EXPOSURE: Positive BCL6 result on ReceptivaDx™ (histologic score 'HSCORE' >1.4) MAIN OUTCOME MEASURES: Pre-receptive ERA result; relative expression levels of endometrial receptivity-associated epithelial genes by single-nucleus sequencing RESULTS: One hundred and seventy-two patients with concurrent ERA and ReceptivaDx evaluation were included in the analysis: 40 were BCL6-positive and 132 were BCL6-negative. One patient (2.5%) in the BCL6-positive group had a pre-receptive ERA result, compared to 29 patients (22.0%) in the BCL6-negative group (p<0.01). BCL6 positivity was associated with decreased odds of a pre-receptive ERA result (OR 0.09 95%CI [0.01-0.69], p=0.02). Single-nucleus transcriptomic analysis of 5,718 epithelial cell nuclei from four individuals showed significant cell type-specific transcriptomic changes associated with a positive ReceptivaDx BCL6 result in both natural cycle (NC) and programmed cycle (PC) endometrium: there were 2,801 significantly differentially expressed genes (DEGs) comparing NC BCL6-positive to -negative, and 1,062 DEGs comparing PC BCL6-positive to -negative. Of the 34 receptivity-associated epithelial markers evaluated, 16 were significantly upregulated in NC BCL6-positive versus -negative endometrium epithelial nuclei. In PC epithelial nuclei, 12 of the 34 receptivity-associated genes were significantly upregulated, while only 1 was significantly downregulated in BCL6-positive versus -negative endometrium. CONCLUSIONS: A positive ReceptivaDx BCL6 result does not correlate with a pre-receptive ERA. Epithelial cells from BCL6-positive endometrium did not show significantly decreased expression in most of the receptivity markers evaluated. These findings demonstrate discordance between the interpretation of "endometrial receptivity" by ReceptivaDx and ERA, and highlight the need for further validation of endometrial evaluation methods in fertility treatment.

Single-Cell Multiomics.

Single-cell RNA sequencing methods have led to improved understanding of the heterogeneity and transcriptomic states present in complex biological systems. Recently, the development of novel single-cell technologies for assaying additional modalities, specifically genomic, epigenomic, proteomic, and spatial data, allows for unprecedented insight into cellular biology. While certain technologies collect multiple measurements from the same cells simultaneously, even when modalities are separately assayed in different cells, we can apply novel computational methods to integrate these data. The application of computational integration methods to multimodal paired and unpaired data results in rich information about the identities of the cells present and the interactions between different levels of biology, such as between genetic variation and transcription. In this review, we both discuss the single-cell technologies for measuring these modalities and describe and characterize a variety of computational integration methods for combining the resulting data to leverage multimodal information toward greater biological insight.

Epigenetic remodeling by vitamin C potentiates plasma cell differentiation.

Ascorbate (vitamin C) is an essential micronutrient in humans. The severe chronic deficiency of ascorbate, termed scurvy, has long been associated with increased susceptibility to infections. How ascorbate affects the immune system at the cellular and molecular levels remained unclear. From a micronutrient analysis, we identified ascorbate as a potent enhancer for antibody response by facilitating the IL-21/STAT3-dependent plasma cell differentiation in mouse and human B cells. The effect of ascorbate is unique as other antioxidants failed to promote plasma cell differentiation. Ascorbate is especially critical during early B cell activation by poising the cells to plasma cell lineage without affecting the proximal IL-21/STAT3 signaling and the overall transcriptome. As a cofactor for epigenetic enzymes, ascorbate facilitates TET2/3-mediated DNA modification and demethylation of multiple elements at the Prdm1 locus. DNA demethylation augments STAT3 association at the Prdm1 promoter and a downstream enhancer, thus ensuring efficient gene expression and plasma cell differentiation. The results suggest that an adequate level of ascorbate is required for antibody response and highlight how micronutrients may regulate the activity of epigenetic enzymes to regulate gene expression. Our findings imply that epigenetic enzymes can function as sensors to gauge the availability of metabolites and influence cell fate decisions.