bims-reprim Biomed News
on Reproductive immunology
Issue of 2021‒03‒14
eight papers selected by
Iva Filipovic
Karolinska Institutet

  1. J Reprod Immunol. 2021 Feb 23. pii: S0165-0378(21)00024-3. [Epub ahead of print]145 103294
      In the search for a reliable biomarker able to diagnose immunological causes of infertility, uterine immune cells have been widely investigated. As a result, heterogeneous methods and cutoff values of what constitutes an aberrant number of immune cells have been reported, and a standardized method for quantification is needed. The objective of this study was to compare methods for quantification of immune cells visualized with immunohistochemistry in the endometrium of women in fertility treatment. Evaluation of the density of CD56+, CD16+ and CD163+ cells by conventional microscopy on a semiquantitative scale (low, medium and high) was compared to a continuous count using digital image analysis (DIA) reported as percentage positive cells out of the total number of stromal cells and number of positive cells per mm2, respectively. We previously reported the CD56/CD16 ratio as a possible prognostic marker, and therefore the ratios of CD56/CD16 were compared using two different methods for selecting fields for counting with DIA: one method using principles of systematic random sampling, where glands were excluded, and one method analyzing large parts of the tissue including glands. A significant association between conventional microscopy and DIA was found when the semiquantitative scale was compared to medians of positive cells in CD56, CD16 and CD163, respectively, p < 0.001. A systematic significant difference in the ratios of CD56/CD16 was found when comparing the two methods for field selection, p < 0.001. To determine the possible use of these methods, more knowledge of the correlation to clinical outcome is warranted.
    Keywords:  Digital Image Analysis; Endometrium; Macrophages; Recurrent implantation failure; Uterine NK cells
  2. Lupus Sci Med. 2021 03;pii: e000463. [Epub ahead of print]8(1):
      OBJECTIVE: Women with SLE face an increased risk of adverse pregnancy outcomes compared with healthy women, but the underlying immunological mechanisms are unknown. Given the recognised association of neutrophil activation with SLE pathogenesis, we examined whether there is increased neutrophil activation and inflammation in blood and placenta in SLE relative to healthy pregnancy.METHODS: At delivery, peripheral blood, maternal-derived intervillous blood and placentas were collected from 12 SLE and 10 healthy control pregnancies. The proportion of low-density granulocytes (LDGs) and the activation status of LDG and normal-density granulocytes were examined with flow cytometry. The chemokines CXCL8 and CXCL1 were quantified with a cytometric bead-based assay and interferon alpha (IFNα) protein levels with a Simoa method. IFNα-stimulated maternal-derived decidual stromal cells were examined for CXCL8 gene expression with qPCR. A pathologist, blinded to the patient background, examined all placentas.
    RESULTS: Women with SLE had significantly higher proportions of LDG in peripheral blood compared with controls (p=0.02), and LDG in both peripheral and intervillous blood were more activated in SLE relative to healthy pregnancies (peripheral blood: p=0.002 and intervillous blood: p=0.05). There were higher levels of CXCL8 and CXCL1 in intervillous compared with peripheral blood in women with SLE (p=0.004 and p=<0.0001, respectively) but not in controls. In SLE pregnancy, IFNα was detectable in 6 out of 10 intervillous blood samples but only in one control. Stimulation with IFNα upregulated CXCL8 gene expression in decidual stromal cells from both SLE and healthy pregnancy. Histological chorioamnionitis was present in 6 out of 12 placentas from women with SLE and in 1 out of 10 controls.
    CONCLUSIONS: In women with SLE, locally produced chemokines in the placenta are increased and may attract and activate neutrophils. This in turn could contribute to placental inflammation and dysfunction and increased risk of placenta-related pregnancy complications.
    Keywords:  chemokines; fibroblasts; lupus erythematosus; systemic
  3. Endocrinology. 2021 Mar 10. pii: bqab054. [Epub ahead of print]
      The molecular interactions between the maternal environment and the developing embryo that are key for early pregnancy success and are influenced by factors such as maternal metabolic status. Our understanding of the mechanism(s) through which these individual nutritional stressors alter endometrial function and the in utero environment for early pregnancy success is, however, limited. Here we report, for the first time, the use of an endometrium-on-a-chip microfluidics approach to produce a multi-cellular endometrium in vitro. Isolated endometrial cells (epithelial and stromal) from the uteri of non-pregnant cows in the early-luteal phase (Day 4-7), were seeded in the upper chamber of the device (epithelial cells; 4-6 10 4 cells/mL) and stromal cells seeded in the lower chamber (1.5-2 10 4 cells/mL). Exposure of cells to different concentrations of glucose (0.5, 5.0 or 50 mM) or insulin (Vehicle, 1 or 10 ng/mL) were performed at a flow rate of 1µL/min for 72 hr. Quantitative differences in the cellular transcriptome and the secreted proteome of in vitro-derived uterine luminal fluid (ULF) were determined by RNA-sequencing and Tandem Mass Tagging Mass Spectrometry (TMT-MS), respectively. High glucose concentrations altered 21 and 191 protein-coding genes in epithelial and stromal cells, respectively (p<0.05), with a dose-dependent quantitative change in the protein secretome (1 and 23 proteins). Altering insulin concentrations resulted in limited transcriptional changes including transcripts for insulin-like binding proteins that were cell specific but altered the quantitative secretion of 196 proteins. These findings highlight one potential mechanism by which changes to maternal glucose and insulin alter uterine function.
    Keywords:  Endometrium-on-a-chip; bovine; cattle; microfluidics; uterine luminal fluid; uterus
  4. Elife. 2021 Mar 09. pii: e67169. [Epub ahead of print]10
      Comparing the genes expressed at the maternal-fetal interface in different species helps to pinpoint those that contribute to a healthy pregnancy by regulating the activity of the immune system.
    Keywords:  endometrium; eutheria; human; marsupial; monotreme; placenta; pregnancy
  5. Front Immunol. 2021 ;12 646596
    Keywords:  complement; infection; innate immunity; innate lymphoid cells; pregnancy
  6. FASEB J. 2021 Apr;35(4): e21285
      The endometrium is a dynamic tissue that exhibits remarkable resilience to repeated episodes of differentiation, breakdown, regeneration, and remodeling. Endometrial physiology relies on a complex interplay between the stromal and epithelial compartments with the former containing a mixture of fibroblasts, vascular, and immune cells. There is evidence for rare populations of putative mesenchymal progenitor cells located in the perivascular niche of human endometrium, but the existence of an equivalent cell population in mouse is unclear. We used the Pdgfrb-BAC-eGFP transgenic reporter mouse in combination with bulk and single-cell RNA sequencing to redefine the endometrial mesenchyme. In contrast to previous reports we show that CD146 is expressed in both PDGFRβ + perivascular cells and CD31 + endothelial cells. Bulk RNAseq revealed cells in the perivascular niche which express the high levels of Pdgfrb as well as genes previously identified in pericytes and/or vascular smooth muscle cells (Acta2, Myh11, Olfr78, Cspg4, Rgs4, Rgs5, Kcnj8, and Abcc9). scRNA-seq identified five subpopulations of cells including closely related pericytes/vascular smooth muscle cells and three subpopulations of fibroblasts. All three fibroblast populations were PDGFRα+/CD34 + but were distinct in their expression of Ngfr/Spon2/Angptl7 (F1), Cxcl14/Smoc2/Rgs2 (F2), and Clec3b/Col14a1/Mmp3 (F3), with potential functions in the regulation of immune responses, response to wounding, and organization of extracellular matrix, respectively. Immunohistochemistry was used to investigate the spatial distribution of these populations revealing F1/NGFR + cells in most abundance beside epithelial cells. We provide the first definitive analysis of mesenchymal cells in the adult mouse endometrium identifying five subpopulations providing a platform for comparisons between mesenchymal cells in endometrium and other adult tissues which are prone to fibrosis.
    Keywords:  CD146; chondroitin sulfate proteoglycan 4; endometrium; fibroblast; pericyte; platelet-derived growth factor beta
  7. J Allergy Clin Immunol. 2021 Mar 05. pii: S0091-6749(21)00360-2. [Epub ahead of print]
      BACKGROUND: Prenatal exposure to infections can modify immune development. These environmental disturbances during early life potentially alter the incidence of inflammatory disorders as well as priming of immune responses. Infection with the helminth Schistosoma mansoni is widely studied for its ability to alter immune responsiveness, and associated with variations in co-infection, allergy, and vaccine efficacy in endemic populations.OBJECTIVE: Exposure to maternal schistosomiasis during early life, even without transmission of infection, can result in priming effects on offspring immune responses to bystander antigenic challenges as relate to allergic responsiveness and vaccination, with this work seeking to clarify further effects and underlying immunological imprinting.
    METHODS: Here, we combine a chronic maternal schistosomiasis infection model with a thorough analysis of subsequent offspring immune responses to allergy and vaccination models, including viral challenge and steady state changes to immune cell compartments.
    RESULTS: We demonstrate that maternal schistosomiasis alters CD4+ responses during allergic sensitization and challenge, in a skewed IL-4/B-cell-dominant response to antigenic challenge associated with limited inflammatory response. Beyond that, we uncover previously unidentified alterations to CD8+ T cell responses during immunization, dependent upon vaccine formulation, that have functional impact upon the efficacy of vaccination against viral infection in a murine Hepatitis B virus model.
    CONCLUSION: Alongside steady-state modifications to CD4+ T cell polarization and B cell priming, we trace these modified CD8+ responses to an altered dendritic cell phenotype sustained into adulthood, providing evidence for complex priming effects imparted by infection via fetomaternal crosstalk.
    Keywords:  dendritic cells; early life determinants of allergy and immune disease; fetomaternal crosstalk; immune priming; immunoregulation; innate memory; schistosomiasis