Biology subjects

Saunders, P.

Publications and source records attributed to Saunders, P..

3 recordsLinked to original sources

bioRxiv2020

Peritoneal macrophage phenotype correlates with pain scores in women with suspected endometriosis

ObjectiveTo characterise peritoneal macrophage populations in women with suspected endometriosis and assess if they are correlated with severity of pelvic pain symptoms. DesignFlow cytometry analysis of peritoneal fluid samples and clinical data. SettingUniversity Research Institute. PatientsClinical questionnaires, surgical data and peritoneal fluid were collected with informed consent from women undergoing diagnostic laparoscopy for suspected endometriosis (n=54). Intervention(s)None Main Outcome Measure(s)Severity of pelvic pain symptoms was assessed by the EHP-30 questionnaire. Immune cells recovered from peritoneal fluid were analysed by flow cytometry. ResultsPain scores (pain domain of EHP30) did not differ according to endometriosis diagnosis, stage of endometriosis or whether or not women were receiving hormone treatment. Analysis of immune cells in peritoneal fluid revealed two populations of peritoneal macrophages: CD14high and CD14low which were not altered by menstrual cycle phase or hormone treatment. CD14high peritoneal macrophages were increased in women with endometriosis compared to those without but were not altered by coincident reproductive health issues such as infertility or heavy menstrual bleeding. Peritoneal macrophage phenotype correlated with pelvic pain symptoms in women with suspected endometriosis. Notably, CD14high peritoneal macrophages negatively correlated with pain scores whereas CD14low peritoneal macrophages were positively correlated. This association was independent of endometriosis diagnosis. ConclusionPeritoneal macrophage phenotypes correlate with pelvic pain symptoms in women with suspected endometriosis and are altered by presence of disease. These results provide new insight into the association between endometriosis pathophysiology and pelvic pain symptoms.

immunology↗

bioRxiv2020

Meiosis reveals the early steps in the evolution of a neo-XY sex chromosome pair in the African pygmy mouse Mus minutoides

Sex chromosomes of eutherian mammals are highly different in size and gene content, and share only a small region of homology (pseudoautosomal region, PAR). They are thought to have evolved through an addition-attrition cycle involving the addition of autosomal segments to sex chromosomes and their subsequent differentiation. The events that drive this process are difficult to investigate because sex chromosomes in most mammals are at a very advanced stage of differentiation. Here, we have taken advantage of a recent translocation of an autosome to both sex chromosomes in the African pygmy mouse Mus minutoides, which has restored a large segment of homology (neo-PAR). By studying meiotic sex chromosome behavior and identifying fully sex-linked genetic markers in the neo-PAR, we demonstrate that this region shows unequivocal signs of early sex-differentiation. First, synapsis and resolution of DNA damage intermediates are delayed in the neo-PAR during meiosis. Second, recombination is suppressed in a large portion of the neo-PAR. However, the inactivation process that characterizes sex chromosomes during meiosis does not extend to this region. Finally, the sex chromosomes show a dual mechanism of association at metaphase-I that involves the formation of a chiasma in the neo-PAR and the preservation of an ancestral achiasmate mode of association in the non-homologous segments. We show that the study of meiosis is crucial to apprehend the onset of sex chromosome differentiation, as it introduces structural and functional constrains to sex chromosome evolution. Synapsis and DNA repair dynamics are the first processes affected in the incipient differentiation of X and Y chromosomes, and they may be involved in accelerating their evolution. This provides one of the very first reports of early steps in neo-sex chromosome differentiation in mammals, and for the first time a cellular framework for the addition-attrition model of sex chromosome evolution. AUTHOR SUMMARYThe early steps in the evolution of sex chromosomes are particularly difficult to study. Cessation of recombination around the sex-determining locus is thought to initiate the differentiation of sex chromosomes. Several studies have investigated this process from a genetic point of view. However, the cellular context in which recombination arrest occurs has not been considered as an important factor. In this report, we show that meiosis, the cellular division in which pairing and recombination between chromosomes takes place, can affect the incipient differentiation of X and Y chromosomes. Combining cytogenetic and genomic approaches, we found that in the African pygmy mouse Mus minutoides, which has recently undergone a sex chromosome-autosome fusion, synapsis and DNA repair dynamics are altered along the newly added region of the sex chromosomes, likely interfering with recombination and thus contributing to the genetic isolation of a large segment of the Y chromosome. Therefore, the cellular events that occur during meiosis are crucial to understand the very early stages of sex chromosome differentiation. This can help to explain why sex chromosomes evolve very fast in some organisms while in others they have barely changed for million years.

genetics↗

bioRxiv2019

Profiling the expression and function of ER46 in human endometrial tissues and uterine NK cells

Study questionDoes the oestrogen receptor isoform, ER46, contribute to regulation of endometrial function?\n\nSummary answerER46 is expressed in endometrial tissues during the proliferative and secretory phases and is the predominant ER isoform in first trimester decidua. ER46 is abundantly expressed in uterine NK (uNK) cells and localised to the cell membrane. Activation of ER46 regulates the function of human uNK cells by increasing cell motility.\n\nWhat is known alreadyOestrogens acting via their cognate receptors are essential regulators of endometrial function and play key roles in establishment of pregnancy. ER46 is a 46kDa truncated isoform of full length ER (ER66, encoded by ESR1) that contains both ligand and DNA binding domains. Expression of ER46 in human endometrium has not been investigated previously. ER46 is located at the cell membrane of peripheral blood leukocytes and mediates rapid responses to oestrogens. UNK cells are a phenotypically distinct (CD56brightCD16-) population of tissue-resident immune cells that regulate vascular remodelling within the endometrium and decidua. We have shown that oestrogens stimulate rapid increases in uNK cell motility. Previous characterisation of uNK cells suggests they are ER66-negative but expression of ER46 has not been characterised. We hypothesise that uNK cells express ER46 and that rapid responses to oestrogens are mediated via this receptor.\n\nStudy design, size, durationThis laboratory-based study used primary human endometrial (n=24) and decidual tissue biopsies (n=30) as well as uNK cells which were freshly isolated from first trimester human decidua (n=18).\n\nParticipants/materials, setting, methodsPrimary human endometrial and first trimester decidual tissue biopsies were collected using methods approved by the local institutional ethics committee (LREC/05/51104/12 and LREC/10/51402/59). The expression of oestrogen receptors (ER66, ER46 and ER{beta}) was assessed by qPCR, western blot and immunohistochemistry. Uterine Natural Killer (uNK) cells were isolated from first trimester human decidua by magnetic bead sorting. Cell motility of uNK cells was measured by live cell imaging: cells were treated with oestradiol (E2)-BSA (10nM equivalent), the ER{beta}-selective agonist 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; 10nM) or vehicle control (DMSO).\n\nMain results and the role of chanceER46 was detected in proliferative and secretory phase tissues and was the predominant ER isoform in first trimester decidua samples. Immunohistochemistry revealed ER46 was co-localised with ER66 in cell nuclei during the proliferative phase but detected in both the cytoplasm and cell membrane of stromal cells in the secretory phase and in decidua. Triple immunofluorescence staining of decidua tissues identified expression of ER46 in the cell membrane of CD56-positive uNK cells which were otherwise ER66-negative. Profiling of isolated uNK cells confirmed expression ER46 and localised ER46 protein to the cell membrane. Functional analysis of isolated uNK cells using live cell imaging demonstrated that activation of ER46 with E2-BSA significantly increased uNK cell motility.\n\nLimitations, reasons for cautionExpression patterns in endometrial tissue was only determined using samples from proliferative and secretory phases. Assessment of first trimester decidua samples was from a range of gestational ages which may have precluded insights into gestation specific changes in these tissues. Our results are based on in vitro responses of primary human cells and we cannot be certain that similar mechanisms occur in situ.\n\nWider implications of the findingsE2 is an essential regulator of reproductive competence. This study provides the first evidence for expression of ER46 in human endometrium and decidua of early pregnancy. We describe a mechanism for regulating the function of human uNK cells via expression of ER46 and demonstrate that selective targeting with E2-BSA regulates uNK cell motility. These novel findings identify a role for ER46 in human endometrium and provide unique insight into the importance of membrane-initiated signalling in modulating the impact of E2 on uNK cell function in women.\n\nStudy funding/competing interest(s)These studies were supported by MRC Programme Grants G1100356/1 and MR/N024524/1 to PTKS. HODC was supported by MRC grant G1002033.

physiology↗