Selma Boulenouar

Paternal MHC expression on mouse trophoblast affects uterine vascularization and fetal growth

The mammalian fetus represents a semiallograft within the maternal uterus yet is not rejected. This situation is particularly pronounced in species with a hemochorial type of placentation, such as humans and rodents, where maternal tissues and blood are in direct contact with fetal trophoblast and thus potentially with paternal antigens. The main polymorphic antigens responsible for graft rejection are MHC antigens. In humans the trophoblast cells invading into the decidua have a unique pattern of MHC class I expression characterized by both classical (HLA-C) and nonclassical (HLA-G and HLA-E) molecules. Whether such an unusual MHC repertoire on the surface of trophoblast is a conserved feature between species with hemochorial placentation has not been resolved. Here we demonstrate, using a range of methods, that C57BL/6 mouse trophoblast predominantly expresses only one MHC class I antigen, H2-K, at the cell surface of giant cells but lacks expression of nonclassical MHC molecules. Antigenic disparity between parental MHCs affects trophoblast-induced transformation of the uterine vasculature and, consequently, placental and fetal gowth. Maternal uterine blood vessels were more dilated, allowing for increased blood supply, in certain combinations of maternal and paternal MHC haplotypes, and these allogeneic fetuses and placentas were heavier at term compared with syngeneic controls. Thus, maternal–fetal immune interactions are instrumental to optimize reproductive success. This cross-talk has important implications for human disorders of pregnancy, such as preeclampsia and fetal growth restriction.

Effects of HPV-16 E5, E6 and E7 proteins on survival, adhesion, migration and invasion of trophoblastic cells

Among high-risk human papillomaviruses (HPV), HPV-16 infection is the most prevalent causative factor for cervical cancer. Beside other mucosal targets, HPV-16 was reported to infect the placenta and to replicate in trophoblastic cells. Since these cells share invasive properties of tumoral cells, they represent an ideal model to investigate several oncogenic processes. In the present work, we analyzed the impacts of HPV-16 E5, E6 and E7 oncoproteins on the trophoblastic model. Our results showed that E5 impaired the viability of trophoblastic and cervical cell lines but E6 and E7, favoring cell growth, neutralized the E5 cytotoxic effect. In addition, E5 decreased the adhesiveness of trophoblastic cells to the tissue culture plastic and to endometrial cells similarly as described previously for E6 and E7. E5 and E6 plus E7 increased also their migration and their invasive properties. Cells expressing HPV-16 early proteins under the control of the long control region endogenous promoter displayed growth advantage and were also more motile and invasive compared with control cells. Interestingly, the E-cadherin was downregulated in trophoblastic cells expressing E5, E6 and E7. Nuclear factor-kappaB and activator protein-1 activities were also enhanced. In conclusion, HPV-16 early proteins enhanced trophoblastic growth and intensify the malignant phenotype by impairing cell adhesion leading to increased cellular motile and invasive properties. HPV-16 E5 participated, with E6 and E7, in these changes by impairing E-cadherin expression, a hallmark of malignant progression.

Composition, Development, and Function of Uterine Innate Lymphoid Cells

Innate lymphoid cells (ILCs), including NK cells, contribute to barrier immunity and tissue homeostasis. In addition to the role of uterine NK cells in placentation and fetal growth, other uterine ILCs (uILCs) are likely to play roles in uterine physiology and pathology. In this article, we report on the composition of uILCs in the endometrium during the luteal phase and in the decidua during early pregnancy. Whereas nonkiller uILC1s and uILC2s are barely detectable in mouse and not detected in humans, a sizeable population of uILC3s is found in human endometrium and decidua, which are mostly NCR+ and partially overlap with previously described IL-22–producing uterine NK cells. Development of mouse uILC3 is Nfil3 independent, suggesting unique features of uILCs. Indeed, although the cytokine production profile of mouse uILCs recapitulates that described in other tissues, IL-5, IL-17, and IL-22 are constitutively produced by uILC2s and uILC3s. This study lays the foundation to understand how ILCs function in the specialized uterine mucosa, both in tissue homeostasis and barrier immunity and during pregnancy.

How does variability of immune system genes affect placentation

Formation of the placenta is a crucial step in mammalian pregnancy. Apart from its function in ensuring an optimal supply of nutrients and oxygen to the fetus, the placenta is also the interface at which allo-recognition of invading trophoblast cells by the maternal immune system can potentially occur. We summarise here the “state of the art” on how variability of immune system genes that code for major histocompatibility complex (MHC) molecules and natural killer receptors (NKR) may impact on human placentation. MHC and NKR are the most polymorphic human genes. Our recent reports point out that specific combinations of fetal MHC and maternal NKR genes in humans correlate with the risk of pre-eclampsia, recurrent miscarriage (RM) and fetal growth restriction (FGR). Research in this field is still at an early stage and future studies in mouse and humans will be needed before the results can be translated to clinical applications. We discuss our recent work, as well as the opportunities offered by mouse genetics, to understand the cellular and molecular mechanisms underlying immune interactions at the maternal-fetal interface.

Airway structural cells regulate TLR5-mediated mucosal adjuvant activity

Antigen-presenting cell (APC) activation is enhanced by vaccine adjuvants. Most vaccines are based on the assumption that adjuvant activity of Toll-like receptor (TLR) agonists depends on direct, functional activation of APCs. Here, we sought to establish whether TLR stimulation in non-hematopoietic cells contributes to flagellin’s mucosal adjuvant activity. Nasal administration of flagellin enhanced T-cell-mediated immunity, and systemic and secretory antibody responses to coadministered antigens in a TLR5-dependent manner. Mucosal adjuvant activity was not affected by either abrogation of TLR5 signaling in hematopoietic cells or the presence of flagellin-specific, circulating neutralizing antibodies. We found that flagellin is rapidly degraded in conducting airways, does not translocate into lung parenchyma and stimulates an early immune response, suggesting that TLR5 signaling is regionalized. The flagellin-specific early response of lung was regulated by radioresistant cells expressing TLR5 (particularly the airway epithelial cells). Flagellin stimulated the epithelial production of a small set of mediators that included the chemokine CCL20, which is known to promote APC recruitment in mucosal tissues. Our data suggest that (i) the adjuvant activity of TLR agonists in mucosal vaccination may require TLR stimulation of structural cells and (ii) harnessing the effect of adjuvants on epithelial cells can improve mucosal vaccines.

Adipose Type One Innate Lymphoid Cells Regulate Macrophage Homeostasis through Targeted Cytotoxicity

SUMMARY Adipose tissue has a dynamic immune system that adapts to changes in diet and maintains homeostatic tissue remodeling. Adipose type 1 innate lymphoid cells (AT1‐ILCs) promote pro‐inflammatory macrophages in obesity, but little is known about their functions at steady state. Here we found that human and murine adipose tissue harbor heterogeneous populations of AT1‐ILCs. Experiments using parabiotic mice fed a high‐fat diet (HFD) showed differential trafficking of AT1‐ILCs, particularly in response to short‐ and long‐term HFD and diet restriction. At steady state, AT1‐ILCs displayed cytotoxic activity toward adipose tissue macrophages (ATMs). Depletion of AT1‐ILCs and perforin deficiency resulted in alterations in the ratio of inflammatory to anti‐inflammatory ATMs, and adoptive transfer of AT1‐ILCs exacerbated metabolic disorder. Diet‐induced obesity impaired AT1‐ILC killing ability. Our findings reveal a role for AT1‐ILCs in regulating ATM homeostasis through cytotoxicity and suggest that this function is relevant in both homeostasis and metabolic disease. Graphical Abstract Figure. No Caption available. HighlightsAT1‐ILCs are enriched in mouse and human adipose tissue and are predominantly tissue residentAT1‐ILCs kill adipose tissue macrophages (ATMs) and maintain ATM homeostasisSubsets of AT1‐ILCs infiltrate adipose tissue during the onset of obesityIn obesity, AT1‐ILCs are reduced and lose their ability to kill &NA; Boulenouar et al. define different subsets of type 1 innate lymphoid cells (AT1‐ILCs) in human and murine adipose tissues and show that at steady state, AT1‐ILCs kill adipose tissue macrophages (ATMs). In obesity, cytotoxicity is impaired. Interference with AT1‐ILC cytotoxicity impacted ATM homeostasis and systemic metabolism, pointing to its importance in homeostasis and disease.

The Residual Innate Lymphoid Cells in NFIL3-Deficient Mice Support Suboptimal Maternal Adaptations to Pregnancy

Uterine NK cells are innate lymphoid cells (ILC) that populate the uterus and expand during pregnancy, regulating placental development and fetal growth in humans and mice. We have recently characterized the composition of uterine ILCs (uILCs), some of which require the transcription factor NFIL3, but the extent to which NFIL3-dependent cells support successful reproduction in mice is unknown. By mating Nfil3−/− females with wild-type males, here we show the effects of NFIL3 deficiency in maternal cells on both the changes in uILCs during pregnancy and the downstream consequences on reproduction. Despite the presence of CD49a+Eomes− uILC1s and the considerable expansion of residual CD49a+Eomes+ tissue-resident NK cells and uILC3s in pregnant Nfil3−/− mice, we found incomplete remodeling of uterine arteries and decidua, placental defects, and fetal growth restriction in litters of normal size. These results show that maternal NFIL3 mediates non-redundant functions in mouse reproduction.

Evaluation of quantitative polymerase chain reaction markers for the detection of breast cancer cells in ovarian tissue stored for fertility preservation

OBJECTIVE To develop molecular tools increasing the sensitivity of breast cancer micrometastases detection within ovarian tissue cryopreserved for fertility preservation. DESIGN Expression of breast markers was evaluated by quantitative polymerase chain reaction in ovarian tissue from patients with benign or cancerous diseases. Suspected tissues were long-term xenografted into mice. SETTING Academic research institute. PATIENT(S) Patients undergoing a fertility preservation procedure. INTERVENTION(S) Ovarian tissue was processed for RNA extraction and quantitative polymerase chain reaction analysis. Cryopreserved ovarian cortex from patients with breast cancer or benign disease was grafted for 6 months into severe combined immunodeficiency mice. MAIN OUTCOMES MEASURE(S) Predictive values of mammaglobin 1 (MGB-1), gross cystic disease fluid protein-15 (GCDFP-15), small breast epithelial mucine (SBEM), and mammaglobin 2 (MGB-2) to detect breast cancer cells in ovarian tissue, and the potential development of cancerous disease after xenograft of ovarian cortex from breast cancer patients. RESULT(S) MGB-1 and GCDFP-15 presented the highest predictive values to detect breast cancer micrometastases in the ovarian cortex, with an efficiency reaching 100% and 77%, respectively. The MGB-2 assay resulted in a high false-positive rate (47%) in the ovarian cortex but could be used to detect breast cancer cells in ovarian medulla. MGB-1 was detected in three of five ovarian cortex samples from early-stage breast cancer patients but not in the ovarian tissue from advanced breast cancer patients (none of 10). None of the mice grafted with ovarian tissue expressing these markers developed cancerous disease. CONCLUSION(S) MGB-1, GCDFP-15, and MGB-2 can serve as molecular markers for the detection of breast cancer micrometastases within the ovarian tissue of breast cancer patients. However, the clinical relevance of such a highly sensitive assay must be further investigated.

The trophoblast: a model to study HPV transcription, replication and host cell interactions

Background Hallmarks of HPV infection include a restricted tropism for human epithelial cells and a viral life cycle tightly linked to the differentiation program of the host cells. This has hampered the study of the HPV vegetative life cycle. Previous studies reported that the tissue and differentiation dependence seemed to be dictated by viral transcription rather than viral DNA replication.