Brendan Browne

Uterine natural killer cells (uNK) play an important role in promoting successful pregnancy by regulating trophoblast invasion and spiral artery remodelling in the first trimester. Recently, single-cell RNA sequencing (scRNAseq) on first-trimester decidua showed that uNK can be divided into three subsets, which may have different roles in pregnancy. Here we present an integration of previously published scRNAseq datasets, together with novel flow cytometry data to interrogate the frequency, phenotype, and function of uNK1-3 in seven stages of the reproductive cycle (menstrual, proliferative, secretory phases of the menstrual cycle; first, second, and third trimester; and postpartum). We found that uNK1 and uNK2 peak in the first trimester, but by the third trimester, the majority of uNK are uNK3. All three subsets are most able to degranulate and produce cytokines during the secretory phase of the menstrual cycle and express KIR2D molecules, which allow them to interact with HLA-C expressed by placental extravillous trophoblast cells, at the highest frequency during the first trimester. Taken together, our findings suggest that uNK are particularly active and able to interact with placental cells at the time of implantation and that uNK1 and uNK2 may be particularly involved in these processes. Our findings are the first to establish how uNK frequency and function change dynamically across the healthy reproductive cycle. This serves as a platform from which the relationship between uNK function and impaired implantation and placentation can be investigated. This will have important implications for the study of subfertility, recurrent miscarriage, pre-eclampsia, and pre-term labour.

PURPOSE: We evaluated the pathophysiology of lichen sclerosus and nonlichen sclerosus urethral stricture disease by comparing protein expression related to inflammation, cell cycle disruption, oxidative stress, hormone receptor status and infection. MATERIALS AND METHODS: Tissue samples were collected from the urethral strictures of 81 patients undergoing urethroplasty. Clinical and demographic data were obtained by chart review. After identifying areas pathognomonic for lichen sclerosus a tissue microarray was created with cores from each sample and immunohistochemistry was performed. RESULTS: Patients had similar baseline demographics and comorbidities. Of the 81 strictures 58 were and 23 were not due to lichen sclerosus. Lichen sclerosus strictures were significantly longer and showed higher levels of inflammation. The proportion of T cells which stained positive for CD8 was significantly higher in strictures due to lichen sclerosus (50% vs 13%, p = 0.004). CCL-4 was expressed significantly more in strictures due to lichen sclerosus (76% vs 42%, p = 0.01). Several other inflammatory markers were only found in strictures due to lichen sclerosus. Block-like p16, a surrogate for high risk human papillomavirus infection, and varicella zoster virus were found only in lichen sclerosus urethral stricture disease samples, although both were rare. Epstein-Barr virus RNA was found in significantly more lichen sclerosus samples (37% vs 10%, p = 0.024). CONCLUSIONS: To our knowledge this is the first study to evaluate protein expression in lichen sclerosus urethral stricture disease. These strictures demonstrate increased inflammation compared to nonlichen sclerosus urethral strictures. Markers of oxidative stress, cell cycle dysregulation and the androgen receptor do not appear to be uniquely associated with lichen sclerosus urethral stricture disease. Positive staining for several viruses in samples of lichen sclerosus urethral stricture disease suggests a possible infectious etiology.