bims-reprim Biomed News
on Reproductive immunology
Issue of 2020‒10‒18
five papers selected by
Iva Filipovic
Karolinska Institutet

  1. Am J Reprod Immunol. 2020 Oct 16. e13358
    Enninga EAL, Jang JS, Hur B, Johnson EL, Wick MJ, Sung J, Chakraborty R.
      PROBLEM: Prenatal exposure to metabolic dysregulation arising from maternal obesity can have negative health consequences in postnatal life. To date, the specific effects of maternal obesity on fetal immunity at a cellular level have not been well characterized.METHOD OF STUDY: Using cord blood mononuclear cells (CBMCs) and cord plasma (n=9/group) isolated from infants born to women with a high BMI (>25kg/m2 ) compared to women with a normal BMI (18-25kg/m2 ), we evaluated differences in immune cell populations using single-cell mass cytometry (CyTOF). CBMCs were matched according to potentially confounding variables, such as maternal and gestational age, ethnicity, smoking status, and gravidity. Statistical results were adjusted for fetal sex. Data was analyzed by viSNE and FlowSOM softwares in CytobankTM .
    RESULTS: In newborn CBMCs from women with high BMI, we observed changes in frequency and phenotype of immune cell populations, including significant increases in CD4+ T cells and decreases in myeloid cell populations. IL-12p40 and MDC concentrations were significantly elevated in the high BMI group compared to control.
    CONCLUSION: This study demonstrates an association between maternal obesity and fetal immunity. Our results warrant following long-term immunologic outcomes and associated clinical risks in children born to women with a high pre-pregnancy BMI.
    Keywords:  Body mass index (BMI); cord blood; immunity; mass cytometry
  2. Hum Reprod. 2020 Oct 15. pii: deaa217. [Epub ahead of print]
    Li C, Chen C, Kang X, Zhang X, Sun S, Guo F, Wang Q, Kou X, Bai W, Zhao A.
      STUDY QUESTION: Do decidua-derived factors stimulate the conversion of circulating neutrophils to polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in early human pregnancy?SUMMARY ANSWER: Circulating neutrophils can acquire PMN-MDSC-like phenotypes and function via phosphorylated signal transducer and activator of transcription 5/programmed death ligand 2 (pSTAT5/PD-L2) signalling after stimulation with decidua-derived granulocyte macrophage colony-stimulating factor (GM-CSF).
    WHAT IS KNOWN ALREADY: PMN-MDSCs are an important immunoregulatory cell type in early pregnancy. Neutrophils are of high heterogeneity and plasticity and can polarize to immunosuppressive PMN-MDSCs upon stimulation.
    STUDY DESIGN, SIZE, DURATION: For analysis of myeloid-derived suppressor cell (MDSC) subset proportions, 12 endometrium tissues and 12 peripheral blood samples were collected from non-pregnant women, and 40 decidua tissues and 16 peripheral blood samples were obtained from women with normal early pregnancy undergoing elective surgical pregnancy termination for nonmedical reasons with gestation age of 6-10 weeks. Twenty-nine decidua tissues were collected for isolation of CD15+ PMN-MDSCs. Twenty endometrium tissues and 30 decidua tissues were collected for cytokine analysis, immunohistochemistry or neutrophil stimulation. Peripheral blood samples were obtained from 36 healthy donors for isolation of CD3+ T cells and CD15+ neutrophils.
    PARTICIPANTS/MATERIALS, SETTING, METHODS: The proportion of MDSC subsets in the decidua and peripheral blood of normal early pregnancy, endometrium and peripheral blood of non-pregnant women was analysed by flow cytometry. The phenotypes and function of decidual PMN-MDSCs and circulating neutrophils were compared by flow cytometry. Circulating neutrophils were stimulated with decidual explant supernatant (DES) and the phenotypes were measured by flow cytometry and immunofluorescence. The suppressive capacity of decidual PMN-MDSCs and DES-conditioned neutrophils was analysed by flow cytometry with or without anti-programmed cell death-1 (PD-1) antibody. Cytokines from DES and endometrial explant supernatant (EES) were detected by a Luminex assay. GM-CSF expression was determined by ELISA and immunohistochemistry. Neutrophils were stimulated with DES, EES, DES with anti-GM-CSF antibody or EES with GM-CSF. CD11b, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), PD-L2 and pSTAT5 expression were measured by flow cytometry.
    MAIN RESULTS AND THE ROLE OF CHANCE: The frequency of PMN-MDSCs was significantly increased in the decidua of early pregnancy compared with peripheral blood of non-pregnant women, the endometrium of non-pregnant women or peripheral blood during early pregnancy. Decidual PMN-MDSCs suppressed T-cell proliferation and cytokine production. Phenotypes of decidual PMN-MDSCs were similar to mature activated neutrophils. DES-induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils. The PD-L2 expression in neutrophils was dependent on STAT5 phosphorylation. Both decidual PMN-MDSCs and DES-conditioned neutrophils suppressed T-cell proliferation via PD-1 signalling. GM-CSF was up-regulated in the decidua and induced CD11b, LOX-1 and PD-L2 expression on neutrophils. DES significantly induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation. Anti-GM-CSF antibody remarkably blocked such stimulation in neutrophils. EES did not induce CD11b, LOX-1, PD-L2 expression or STAT5 phosphorylation, while GM-CSF treatment sufficiently stimulated CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils.
    LIMITATIONS, REASONS FOR CAUTION: The study was based on in vitro experiments and we were not able to evaluate neutrophils differentiation to PMN-MDSCs in other sites before entering the maternal-foetal interface due to the limited availability of human samples. This needs to be explored using murine models.
    WIDER IMPLICATIONS OF THE FINDINGS: This is the first study demonstrating that decidual PMN-MDSCs are a group of immunoregulatory cells with mature status, and that neutrophils can be induced to a PMN-MDSC-like phenotype with decidua-derived GM-CSF via pSTAT5/PD-L2 signalling. This study indicates that GM-CSF can facilitate immune tolerance of early pregnancy through regulating PMN-MDSCs and further provides a potential role of GM-CSF in prevention and treatment for pregnancy complications.
    STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (81671481) and National Natural Science Foundation of China (81871179). All authors have no competing interests to declare.
    Keywords:  GM-CSF; PMN-MDSCs; decidua; early pregnancy; endometrium; immune tolerance; neutrophils
  3. J Mol Med (Berl). 2020 Oct 13.
    Paravati R, De Mello N, Onyido EK, Francis LW, Brüsehafer K, Younas K, Spencer-Harty S, Conlan RS, Gonzalez D, Margarit L.
      Endometrial receptivity is mediated by adhesion molecules at the endometrium-trophoblast interface where osteopontin (OPN) and CD44 form a protein complex that plays an important role in embryo recognition. Here, we undertook a prospective study investigating the expression and regulation of OPN and CD44 in 50 fertile and 31 infertile ovulatory polycystic ovarian syndrome (PCOS) patients in the proliferative and secretory phases of the natural menstrual cycle and in 12 infertile anovulatory PCOS patients. Endometrial biopsies and blood samples were evaluated for expression of OPN and CD44 using RT-PCR, immunohistochemistry and ELISA analysis to determine circulating levels of OPN, CD44, TNF-α, IFN-γ and OPN and CD44 levels in biopsy media. Our findings highlighted an increased level of circulating OPN and CD44 in serum from infertile patients that inversely correlated with expression levels in endometrial tissue and positively correlated with levels secreted into biopsy media. OPN and CD44 levels positively correlated to each other in serum and media from fertile and PCOS patients, as well as to circulating TNF-α and IFN-γ. In vitro analysis revealed that hormone treatment induced recruitment of ERα to the OPN and CD44 promoters with a concomitant increase in the expression of these genes. In infertile patients, inflammatory cytokines led to recruitment of NF-κB and STAT1 proteins to the OPN and CD44 promoters, resulting in their overexpression. These observations suggest that the endometrial epithelial OPN-CD44 adhesion complex is deficient in ovulatory PCOS patients and displays an altered stoichiometry in anovulatory patients, which in both cases may perturb apposition. This, together with elevated circulating and local secreted levels of these proteins, may hinder endometrium-trophoblast interactions by saturating OPN and CD44 receptors on the surface of the blastocyst, thereby contributing to the infertility associated with ovulating PCOS patients. KEY MESSAGES: • Endometrial epithelial OPN-CD44 adhesion complex levels are deficient in ovulatory PCOS patients contributing to the endometrial infertility associated with ovulating PCOS patients. • Circulating levels of OPN, CD44 and inflammatory cytokines TNF-α and IFN-γ are altered in infertile PCOS patients. • Increased levels of both OPN and CD44 in biopsy media and serum inversely correlate with endometrial expression of these markers in endometrial tissue. • In infertile PCOS patients, high levels of oestrogens and inflammatory cytokines stimulate the recruitment of transcription factors to the OPN and CD44 promoters to enhance gene transcription. • Our study identifies a novel crosstalk between the CD44-OPN adhesion complex, ERα, STAT1 and NF-κB pathways modulating endometrial receptivity.
    Keywords:  CD44; Cytokines; Endometrium; Infertility; OPN
  4. Nat Commun. 2020 10 12. 11(1): 5128
    Fenizia C, Biasin M, Cetin I, Vergani P, Mileto D, Spinillo A, Gismondo MR, Perotti F, Callegari C, Mancon A, Cammarata S, Beretta I, Nebuloni M, Trabattoni D, Clerici M, Savasi V.
      The impact of SARS-CoV-2 infection during gestation remains unclear. Here, we analyse the viral genome on maternal and newborns nasopharyngeal swabs, vaginal swabs, maternal and umbilical cord plasma, placenta and umbilical cord biopsies, amniotic fluids and milk from 31 mothers with SARS-CoV-2 infection. In addition, we also test specific anti-SARS-CoV-2 antibodies and expression of genes involved in inflammatory responses in placentas, and in maternal and umbilical cord plasma. We detect SARS-CoV-2 genome in one umbilical cord blood and in two at-term placentas, in one vaginal mucosa and in one milk specimen. Furthermore, we report the presence of specific anti-SARS-CoV-2 IgM and IgG antibodies in one umbilical cord blood and in one milk specimen. Finally, in the three documented cases of vertical transmission, SARS-CoV-2 infection was accompanied by a strong inflammatory response. Together, these data support the hypothesis that in utero SARS-CoV-2 vertical transmission, while low, is possible. These results might help defining proper obstetric management of COVID-19 pregnant women, or putative indications for mode and timing of delivery.
  5. Fetal Pediatr Pathol. 2020 Oct 12. 1-10
    He M, Skaria P, Kreutz K, Chen L, Hagemann IS, Carter EB, Mysorekar IU, Nelson DM, Pfeifer J, Dehner LP.
      BACKGROUND: This study aims to investigate whether maternal SARS-CoV-2 status affects placental pathology. Methods: A retrospective case-control study was conducted by reviewing charts and slides of placentas delivered between April 1 to July 24, 2020. Clinical history of "COVID-19" was searched in Pathology Database (CoPath). Controls were matched with SARS-CoV-2-negative women with singleton deliveries in the 3rd-trimester. Pathological features were extracted from placental pathology reports. Results: Twenty-one 3rd trimester placentas from SARS-CoV-2-positive women were identified and compared to 20 placentas from SARS-CoV-2-negative women. There were no significant differences in individual or group gross or microscopic pathological features. Within the SARS-CoV-2+ group, there are no differences between symptomatic and asymptomatic women. Conclusion: Placentas from SARS-CoV-2-positive women do not demonstrate a specific pathological pattern. Pregnancy complicated with COVID-19 during the 3rd trimester does not have a demonstrable effect on placental structure and pathology.
    Keywords:  COVID-19; pathology; placenta; third trimester