Subclinical endometritis differentially affects the transcriptomic profiles of endometrial glandular, luminal, and stromal cells of postpartum dairy cows.

In postpartum dairy cows, subclinical endometritis (SCE) is characterized by persistent endometrial inflammation, which has profound detrimental effects on subsequent reproductive performance. To date, transcriptomic studies related to this condition were either based on biopsy-derived whole-endometrium tissue or endometrial swab or cytobrush samples, thus masking effects of disease on cell type-specific gene expression. This study tested the hypothesis that different endometrial health statuses are associated with distinct transcription profiles of endometrial stromal, glandular, and luminal epithelial cells. At 44 d postpartum (DPP), endometrial biopsies were taken from dairy cows (n = 24) classified as healthy, recovered from SCE, or affected by persistent SCE, according to endometrial cytology taken at 21 and 44 DPP. Stromal, glandular, and luminal epithelial cells were isolated from the whole-tissue biopsy by laser capture microdissection, and the cell-specific transcription profiles were determined by RNA sequencing. Differential gene expression was analyzed with DESeq2 (https://bioconductor.org/packages/release/bioc/html/DESeq2.html). Results demonstrated that global transcriptomic profiles and corresponding lists of differentially expressed genes between cows with different health statuses were distinct among cell types. Results also showed that although healthy and recovered cows presented similar endometrial clinically healthy phenotypes at 44 DPP, the prior presence of immune cells still affected the transcriptome of endometrial cells at this stage, delaying complete functional recovery. Recovery or persistence of inflammation was associated with gene expression patterns involved not only in immune function but also in tissue remodeling, cell adhesion, and uterine receptivity in a cell type-specific manner. Identifying these signatures may contribute to the development of novel diagnostic tools and therapeutic strategies. In addition, these results may help to define preventive measures or ways to stimulate recovery from endometrial inflammation, thus helping to restore the fertility of postpartum dairy cows.