T follicular helper 17 (Tfh17) cells are superior for immunological memory maintenance.

A defining feature of successful vaccination is the ability to induce long-lived antigen-specific memory cells. T follicular helper (Tfh) cells specialize in providing help to B cells in mounting protective humoral immunity in infection and after vaccination. Memory Tfh cells that retain the CXCR5 expression can confer protection through enhancing humoral response upon antigen re-exposure but how they are maintained is poorly understood. CXCR5+ memory Tfh cells in human blood are divided into Tfh1, Tfh2, and Tfh17 cells by the expression of chemokine receptors CXCR3 and CCR6 associated with Th1 and Th17, respectively. Here, we developed a new method to induce Tfh1, Tfh2, and Tfh17-like (iTfh1, iTfh2, and iTfh17) mouse cells in vitro. Although all three iTfh subsets efficiently support antibody responses in recipient mice with immediate immunization, iTfh17 cells are superior to iTfh1 and iTfh2 cells in supporting antibody response to a later immunization after extended resting in vivo to mimic memory maintenance. Notably, the counterpart human Tfh17 cells are selectively enriched in CCR7+ central memory Tfh cells with survival and proliferative advantages. Furthermore, the analysis of multiple human cohorts that received different vaccines for HBV, influenza virus, tetanus toxin or measles revealed that vaccine-specific Tfh17 cells outcompete Tfh1 or Tfh2 cells for the persistence in memory phase. Therefore, the complementary mouse and human results showing the advantage of Tfh17 cells in maintenance and memory function supports the notion that Tfh17-induced immunization might be preferable in vaccine development to confer long-term protection.

The risk of intrauterine exposure to SARS-CoV-2 in female COVID-19 patients: A comprehensive review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new type of coronavirus that has caused fatal infectious diseases and global spread. This novel coronavirus attacks target cells through the interaction of spike protein and angiotensin-converting enzyme II (ACE2), leading to different clinical symptoms. However, for a successful pregnancy, a well-established in-uterine environment includes a specific immune environment, and multi-interactions between specific cell types are prerequisites. The immune-related changes in patients infected with novel coronavirus could interfere with the immune microenvironment in the uterus, leading to fetal loss. We first reviewed the intrauterine environment in the normal development process and the possible pregnancy outcome in the infection state. Then, we summarized the immune response induced by SARS-CoV-2 in patients and analyzed the changes in ACE2 expression in the female reproductive system. Finally, the present observational evidence of infection in pregnant women was also reviewed.

RhoB Promotes Endometrial Stromal Cells Decidualization Via Semaphorin3A/PlexinA4 Signaling in Early Pregnancy.

Endometrial decidualization refers to a series of morphological changes and functional remodeling of the uterine endometrium to accept the embryo under the effect of estrogen and progesterone secreted by ovaries after ovulation. During decidualization, endometrial stromal cells (ESCs) proliferate and differentiate into decidual stromal cells, undergoing cytoskeletal rearrangement-mediated morphological changes and expressing decidualization markers, such as insulin-like growth factor-binding protein-1 and prolactin. Ras homology (Rho) proteins, a family of small G proteins, are well known as regulators of cellular morphology and involved in multiple other cellular processes. In this study, we found ras homolog family member B (RHOB) was the most significantly upregulated gene in the Rho protein family after the in vitro decidualization of human primary ESCs. RhoB expression was induced mainly by 3',5'-cyclic adenosine 5'-monophosphate (cAMP) / protein kinase A (PKA) / cyclic adenosine monophosphate-response element binding protein signaling and partly by progesterone signaling. Knockdown of RhoB in ESCs greatly inhibited actin cytoskeletal rearrangement, cell morphological transformation, and upregulation of insulin-like growth factor-binding protein-1, suggesting an indispensable role of RhoB in decidualization. Mechanistically, the downstream target of RhoB was semaphorin3A (Sema3A), which mediated its signaling via interacting with the receptor, plexinA4. More importantly, decreased expression of RhoB, Sema3A, and plexinA4 were detected in deciduas from patients with unexplained spontaneous miscarriage. Collectively, our results indicate that RhoB/Sema3A/plexinA4 signaling plays a positive role in endometrial decidualization and relates to unexplained spontaneous miscarriage, which is worthy of further exploration so as to provide new insights into therapeutic strategies for pregnancy diseases associated with poor decidualization.

SCM-198 Prevents Endometriosis by Reversing Low Autophagy of Endometrial Stromal Cell via Balancing ERα and PR Signals.

Background: Endometriosis (EMS), an endocrine-related inflammatory disease, is characterized by estrogen and progesterone imbalance in ectopic lesions. However, its pathogenic mechanism has not been fully elucidated. While SCM-198 is the synthetic form of leonurine and has multiple pharmacological activities such as antioxidation and anti-inflammation, it remains unknown whether it could inhibit the progress of EMS by regulating estrogen signaling and inflammation. Methods: The therapeutic effects of SCM-198 on EMS and its potential mechanism were analyzed by establishing EMS mouse models and performing an RNA sequencing (RNA-seq) assay. ELISA was performed to detect estrogen and tumor necrosis factor (TNF) -α concentrations in normal endometrial stromal cells (nESCs) and ectopic endometrial stromal cells (eESCs) with or without SCM-198 treatment. Western blotting, RNA silencing, and plasmid overexpression were used to analyze the relationship between inflammation, endocrine factors, and autophagy and the regulatory activity of SCM-198 on the inflammation-endocrine-autophagy axis. Results: Increased estrogen-estrogen receptor (ER) α signaling and decreased progesterone receptor isoform B (PRB) expression synergistically led to a hypo-autophagy state in eESCs, which further inhibited the apoptosis of eESCs. The high expression of TNF-α in eESCs enhanced the antiapoptotic effect mediated by low autophagy through the activation of the aromatase-estrogen-ERα signaling pathway. SCM-198 inhibited the growth of ectopic lesions in EMS mice and promoted the apoptosis of eESCs both in vivo and in vitro. The apoptotic effect of SCM-198 on eESCs was attained by upregulating the autophagy level via the inhibition of the TNF-α-activated aromatase-estrogen-ERα signal and the increase in PRB expression. Conclusion: Inflammation facilitated the progress of EMS by disrupting the estrogen regulatory axis. SCM-198 inhibited EMS progression by regulating the inflammation-endocrine-autophagy axis.

Evaluation of inactivated COVID-19 vaccine on semen parameters in reproductive-age males: a retrospective cohort study.

During the coronavirus disease (COVID-19) epidemic, there have been concerns about the impact of vaccines on people's fertility, including the fertility of those who are currently preparing for pregnancy and those who might become pregnant in future. However, there is still a lack of research on the effect of the COVID-19 vaccine on male fertility, and it is not surprising that couples and donors have concerns regarding vaccination. In this study, a retrospective cohort study was conducted to examine semen quality before and after receipt of the inactivated COVID-19 vaccine. There were no statistically significant changes in semen parameters (volume, sperm concentration, progressive motility, and total progressive motile count) after two doses of vaccine (all P > 0.05). In summary, our study updates the most recent studies on the effects of the COVID-19 vaccine on male fertility, and the information from this study could be used to guide fertility recommendations for assisted reproductive technology (ART) patients and donors.

MicroRNA let-7i inhibits granulosa-luteal cell proliferation and oestradiol biosynthesis by directly targeting IMP2.

RESEARCH QUESTION: Increased granulosa cell division is associated with abnormal folliculogenesis in polycystic ovary syndrome (PCOS). Lethal-7i microRNA (let-7i) may play an important role in the follicular development and granulosa cell growth; therefore is let-7i involved in PCOS pathogenesis? DESIGN: The expression of let-7i was measured in granulosa-luteal cells (GLC) from women with or without PCOS. A human granulosa cell line, KGN, was used for the functional study. Mimics and inhibitors of let-7i, lentiviruses expressing insulin-like growth factor 2 mRNA binding protein (IMP2), and small-interfering RNAs were transfected into KGN cells. KGN cell proliferation was determined by 5-ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. The cell cycle and apoptosis were assessed by propidium iodide-annexin V (PI-A) staining and fluorescence-activated cell sorting. Oestradiol concentration was determined by enzyme-linked immunoassay. Bioinformatics analysis and luciferase reporter assay were applied to confirm the let-7i target genes. RESULTS: The study showed that let-7i was down-regulated in PCOS GLC (P = 0.001). Mimics of let-7i inhibited KGN proliferation (P = 0.001), and decreased aromatase expression (P = 0.030) and oestradiol production (P = 0.029), whereas let-7i inhibitors had the opposite effect. Bioinformatics analysis and quantitative real-time (qRT) PCR identified IMP2 as a target of let-7i (P = 0.021). qRT-PCR and western blot analysis indicated that IMP2 was up-regulated in GLC in women with PCOS (P = 0.001 and P = 0.044), and IMP2 expression was suppressed by let-7i in KGN cells (P < 0.001). Luciferase reporter assay results (P = 0.002), combined with the rescue assay, confirmed that let-7i inhibited KGN cell proliferation and reduced oestradiol concentration by directly targeting IMP2. CONCLUSIONS: let-7i was down-regulated in PCOS GLC. Overexpression of let-7i inhibited KGN cell proliferation and decreased oestradiol production in an IMP2-dependent manner, providing a new molecular mechanism for PCOS.

SCM-198 Alleviates Endometriosis by Suppressing Estrogen-ERα mediated Differentiation and Function of CD4+CD25+ Regulatory T Cells.

Background: Endometriosis (EMS), a typical endocrine immune disorder, associates with dramatically increased estrogen production and disorganized immune response in ectopic focus. Peritoneal regulatory T cells (Tregs) expansion in women with EMS and their pathogenic role attributable to endometriotic immunotolerance has been reported. Whether local high estrogen promotes EMS by discipling Tregs needs to be further explored. Up to date, there is no effective medicine for the treatment of EMS. SCM-198 is a synthetic leonurine with multiple physiological activities. Whether SCM-198 could regulate Tregs via estrogen and facilitate the radical cure of EMS has not yet been reported. Methods: Proportion of Tregs in peritoneal fluid of patients with EMS was firstly analyzed via flow cytometry. Peritoneal estrogen concentration and the mRNA levels of estrogen receptor α (ERα) and estrogen receptor ß (ERß) of Tregs were detected by ELISA and RT-PCR, respectively. Grouped in vitro induction assays were performed to explore the effects of SCM-198 and estrogen signaling on Tregs. Cell invasion and viability assays were utilized to detect the crosstalk between Tregs and ectopic endometrial stromal cells (eESCs), with or without SCM-198 treatment. Furthermore, EMS mice models were established to verify the therapeutic effects of SCM-198. Results: Increased Tregs were found in peritoneal fluid of EMS patients, accompanied with estrogen-ERα overactivation. Estrogen-ERα triggered the expansion of Tregs and their cytokine production (IL-10 and TGF-ß1), which could be reversed by SCM-198 treatment. Moreover, SCM-198 abated the invasion and viability of eESCs enhanced by Tregs. In vivo experiments confirmed that SCM-198 obviously retarded the growth of ectopic lesions and downregulated the functions of Tregs via estrogen-ERα inactivation. Conclusions: These data suggest that SCM-198 attenuates Tregs expansion via the inhibition of estrogen-ERα signaling in EMS and offer a promising therapy for such a refractory disease.

Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal-foetal immune tolerance to alleviate early pregnancy failure.

Natural killer (NK) cells preferentially accumulate at maternal-foetal interface and are believed to play vital immune-modulatory roles during early pregnancy and related immunological dysfunction may result in pregnant failure such as recurrent miscarriage (RM). However, the mechanisms underlying the establishment of maternal-foetal immunotolerance are complex but clarifying the roles of decidual NK (dNK) cells offers the potential to design immunotherapeutic strategies to assist RM patients. In this report, we analysed RNA sequencing on peripheral NK (pNK) and decidual NK cells during early pregnancy; we identified an immunomodulatory dNK subset CXCR4+ CD56bright dNK and investigated its origin and phenotypic and functional characteristics. CXCR4+ CD56bright dNK displayed a less activated and cytotoxic phenotype but an enhanced immunomodulatory potential relative to the CXCR4 negative subset. CXCR4+ CD56bright dNK promote Th2 shift in an IL-4-dependent manner and can be recruited from peripheral blood and reprogramed by trophoblasts, as an active participant in the establishment of immune-tolerance during early pregnancy. Diminished CXCR4+ dNK cells and their impaired ability to induce Th2 differentiation were found in RM patients and mouse models of spontaneous abortion. Moreover, adoptive transfer of CXCR4+ dNK cells to NK-deficient (Nfil3-/-) mice showed great therapeutic potential of CXCR4+ dNK via recovering the Th2/Th1 bias and reducing embryo resorption rates. The identification of this new dNK cell subset may lay the foundation for understanding NK cell mechanisms in early pregnancy and provide potential prognostic factors for the diagnosis and therapy of RM.

[Research advances on adrenergic receptor signaling involved in disease microenvironment through regulation of macrophages].

Adrenergic receptor (AR), one of the key receptors for nervous system, plays an important role in the immune microenvironment and the progression of many diseases. In recent years, the regulation of ARs and its signal on macrophages has become a research hotspot. Researchers found that ARs could exert different regulatory functions on macrophages in different microenvironments, which in turn affects occurrence and development of diseases such as tumor, heart failure, obesity, acute injury, infection and pregnancy-related diseases. This review summarizes the expression and functional regulation of ARs on macrophages, and the role of ARs in microenvironment of related diseases, which might provide new ideas for the treatments.

[Research advances in the function of T cells at the maternal-fetal interface].

Immune tolerance at maternal-fetal interface is the basis for establishment and maintenance of successful pregnancy. T cells are pivotal compositions of uterine decidual immune cells, which are required to mediate anti-infection immunity and protect embryos from external antigens attack. T cells also participate in the complex immune regulation process of maternal acceptance of semi-allogeneic embryos, and play an important role in regulating embryo implantation and maintaining pregnancy. Its dysfunction may lead to early pregnancy failures or mid-late pregnancy complications. This review summarizes the compositions, phenotypic characteristics and functions of decidual T cells at the maternal-fetal interface in recent years, and further describes the regulation of decidual CD4+ and CD8+ T cells in maternal-fetal immune tolerance as well as the molecular mechanisms of abnormal regulation leading to early pregnancy failures. Through the in-depth understanding the mechanism of maternal-fetal immune regulation, it supplies a novel concept on maternal-fetal immune tolerance and new clues for the immunotherapy of pregnancy-related diseases.

Leonurine: From Gynecologic Medicine to Pleiotropic Agent.

Leonurus japonicus Houtt, a Chinese traditional herbal medicine, has been widely used to cure gynecological diseases, such as incomplete abortion and menoxenia. Leonurine, a major active alkaloid compound only be found in Leonurus japonicus Houtt, has been successfully extracted and purified. Recent evidence has shown that leonurine can regulate a variety of pathologic processes including oxidative stress, inflammation, fibrosis, apoptosis, and multiple metabolic disorders. Here, we have reviewed the pharmacological actions and biological functions of leonurine, with a focus on the role of leonurine in the amelioration of various pathological processes. Insights into the related signaling pathways and molecular mechanisms have strengthened our understanding on the function of leonurine in the alleviation of multiple pathological states. Our summary of the existing researches should help direct future research into the basic science and clinical applications in related diseases.

Different roles of E proteins in t(8;21) leukemia: E2-2 compromises the function of AETFC and negatively regulates leukemogenesis.

The AML1-ETO fusion protein, generated by the t(8;21) chromosomal translocation, is causally involved in nearly 20% of acute myeloid leukemia (AML) cases. In leukemic cells, AML1-ETO resides in and functions through a stable protein complex, AML1-ETO-containing transcription factor complex (AETFC), that contains multiple transcription (co)factors. Among these AETFC components, HEB and E2A, two members of the ubiquitously expressed E proteins, directly interact with AML1-ETO, confer new DNA-binding capacity to AETFC, and are essential for leukemogenesis. However, the third E protein, E2-2, is specifically silenced in AML1-ETO-expressing leukemic cells, suggesting E2-2 as a negative factor of leukemogenesis. Indeed, ectopic expression of E2-2 selectively inhibits the growth of AML1-ETO-expressing leukemic cells, and this inhibition requires the bHLH DNA-binding domain. RNA-seq and ChIP-seq analyses reveal that, despite some overlap, the three E proteins differentially regulate many target genes. In particular, studies show that E2-2 both redistributes AETFC to, and activates, some genes associated with dendritic cell differentiation and represses MYC target genes. In AML patients, the expression of E2-2 is relatively lower in the t(8;21) subtype, and an E2-2 target gene, THPO, is identified as a potential predictor of relapse. In a mouse model of human t(8;21) leukemia, E2-2 suppression accelerates leukemogenesis. Taken together, these results reveal that, in contrast to HEB and E2A, which facilitate AML1-ETO-mediated leukemogenesis, E2-2 compromises the function of AETFC and negatively regulates leukemogenesis. The three E proteins thus define a heterogeneity of AETFC, which improves our understanding of the precise mechanism of leukemogenesis and assists development of diagnostic/therapeutic strategies.

Asymmetric dimethylarginine contributes to retinal neovascularization of diabetic retinopathy through EphrinB2 pathway.

Diabetic retinopathy (DR) is a leading cause of vision loss with retinal neovascularization. This study aims to investigate whether Asymmetric dimethylarginine (ADMA) impacts the pathogenesis of DR via focusing on promoting retinal neovascularization and its underlying molecular mechanisms. Diabetic rats were induced by a single intraperitoneal injection of streptozotocin (STZ) for 20 weeks. ADMA levels in aqueous and the influence of hypoxia on ADMA and angiogenesis in RF/6A cells were examined. The effects and underlying molecular mechanisms of ADMA on neovascularization of RF/6A cells were further evaluated by administration of ADMA, DDAH siRNA or ephrinB2 siRNA. Results showed that ADMA levels were elevated in both aqueous from diabetic rats and culture medium in RF/6A cells pretreated with hypoxia. Administration of ADMA directly promoted proliferation, migration, adhesion and tube formation of RF/6A cells, which was further confirmed by DDAH1 siRNA or DDAH2 siRNA. In addition, ephrinB2 expression was increased under diabetic conditions, and the angiogenic effects of ADMA were blocked by ephrinB2 siRNA. In conclusion, ADMA contributes to the neovascularization of retina in diabetic mellitus, which is regulated by ephrinB2.

Three macrophage subsets are identified in the uterus during early human pregnancy.

Macrophages are crucial for a successful pregnancy, and malfunctions of decidual macrophages correlate with adverse pregnancy outcomes, such as spontaneous abortion and preeclampsia. Previously, decidual macrophages were often thought to be a single population. In the present study, we identified three decidual macrophage subsets, CCR2-CD11cLO (CD11clow, ~80%), CCR2-CD11cHI (CD11chigh, ~5%), and CCR2+CD11cHI (CD11chigh, 10-15%), during the first trimester of human pregnancy by flow cytometry analysis. CCR2-CD11cLO macrophages are widely distributed in the decidua, while CCR2-CD11cHI and CCR2+CD11cHI macrophages are primarily detected close to extravillous trophoblast cells according to immunofluorescence staining. According to RNA sequencing bioinformatics analysis and in vitro functional studies, these three subsets of macrophages have different phagocytic capacities. CCR2+CD11cHI macrophages have pro-inflammatory characteristics, while the CCR2-CD11cHI population is suggested to be anti-oxidative and anti-inflammatory due to its high expression of critical heme metabolism-related genes, suggesting that these two subsets of macrophages maintain an inflammatory balance at the leading edge of trophoblast invasion to facilitate the clearance of pathogen infection as well as maintain the homeostasis of the maternal-fetal interface. The present study physiologically identifies three decidual macrophage subsets. Further clarification of the functions of these subsets will improve our understanding of maternal-fetal crosstalk in the maintenance of a healthy pregnancy.

Relationship between receipt of substitutable for-fee vaccines and completion of the expanded programme on immunisation: a cross-sectional study in Fujian, China.

OBJECTIVE: The aim of this study was to evaluate the relationship between receipt of the substitutable-for-fee vaccines (SFV) and completion of the expanded programme on immunisation (EPI). DESIGN AND SETTINGS: A cross-sectional study was conducted in Fujian province, China. PARTICIPANTS: Children who were born from 1 September 2009 to 31 August 2011, and who had been residing in the township for at least 3 months, were randomly recruited from 34 townships. MAIN OUTCOMES MEASURES: Outcomes were completion rate of the EPI and coverage rate of the SFV. RESULTS: The study included 1428 children, of whom 1350 (94.5%) finished the EPI and 282 (19.7%) received at least one dose of the SFV. Administration of the SFV was associated with an increased likelihood of completing the EPI (OR=3.2, 95% CI 1.3 to 7.6 in the total sample and OR=4.0, 95% CI 1.7 to 9.6 in the subsample of children in regions with the SFV accessibility). The impact of the SFV administration on completion of the EPI was larger among children whose parents have junior school education or less (97.8% and 97.9% vs 92.5% and 91.9%, both p<0.001) and among those with a timely hepatitis B vaccine first dose (98.5% vs 94.0%, p<0.001). CONCLUSIONS: Receipt of SFV is associated with increased likelihood of completion of the EPI in Fujian, China.

dNK cells facilitate the interaction between trophoblastic and endothelial cells via VEGF-C and HGF.

Decidual NK (dNK) cells, identified as CD56brightCD16-CD3-, account for ~70% of lymphocytes within the uterine wall during early pregnancy. Accumulating evidence suggests that tight interactions between placental trophoblasts and dNK cells are critical for trophoblast cell differentiation. However, the underlying mechanism remains to be explored in detail. In the present study, conditioned medium (CM) was collected from cultured primary human dNK cells. Primary cytotrophoblasts (CTBs) or the human trophoblast cell line HTR8/SVneo was treated with dNK-CM and co-cultured with human umbilical vein endothelial cells (HUVECs) in a three-dimensional Matrigel scaffold, and the formation of tube structures was dynamically monitored with live cell imaging. Trophoblast invasion was analyzed with a transwell invasion assay. The data demonstrated that the treatment of HTR8/SVneo cells or CTBs with dNK-CM remarkably promoted trophoblast invasion and tube formation in the presence of HUVECs. The epithelial marker E-cadherin was reduced, while the expression of endothelial markers NCAM, VE-cadherin and integrin ß1 was significantly promoted in the HTR8/SVneo cells upon treatment with dNK-CM. Antibody blocking experiments revealed that the dNK cells promoted trophoblast invasion through the production of IL-8 and HGF, and they induced trophoblast differentiation toward endothelial phenotype by producing VEGF-C and HGF. These results provide new evidence to clarify the finely tuned interactions between trophoblasts and dNK cells at the maternal-fetal interface.

Tim-3 and PD-1 regulate CD8+ T cell function to maintain early pregnancy in mice.

During pregnancy, CD8+ T cells are important regulators in the balance of fetal tolerance and antiviral immunity. T-cell immunoglobulin mucin-3 (Tim-3) and programmed cell death-1 (PD-1) are well-recognized negative co-stimulatory molecules involved in viral persistence and tumor metastasis. Here, we demonstrate that CD8+ T cells co-expressing Tim-3 and PD-1 were down-regulated in the deciduae of female mice in abortion-prone matings compared with normal pregnant mice. In addition to their reduced numbers, the Tim-3+PD-1+CD8+ T cells produced lower levels of the anti-inflammatory cytokines interleukin (IL)-4 and IL-10, as well as a higher level of the pro-inflammatory cytokine interferon (IFN)-γ, relative to those from normal pregnancy. Furthermore, normal pregnant CBA/J females challenged with Tim-3- and/or PD-1-blocking antibodies were more susceptible to fetal resorption. These findings indicate that Tim-3 and PD-1 pathways play critical roles in regulating CD8+ T cell function and maintaining normal pregnancy.

Co-Signaling Molecules in Maternal-Fetal Immunity.

Physiologically, a successful pregnancy requires the maternal immune system to recognize and tolerate the semiallogeneic fetus, and allow for normal invasion of trophoblasts. Thus, pregnancy complications are considered to be associated with dysfunctional maternal-fetal crosstalk. Co-signaling molecules are a group of cell surface molecules that positively or negatively modulate the immune response. Well studied in the fields of oncology and transplantation, they are also suggested to be involved in maternal-fetal crosstalk. Here, we review the latest knowledge on the expression and function of such co-signaling molecules, highlighting their immunoregulatory roles in maternal-fetal tolerance and decidual vascular remodeling, and their involvement in pathological pregnancies. This review may instruct future basic research on, and clinical applications for, maternal-fetal immunity.