Placental Galectins Are Key Players in Regulating the Maternal Adaptive Immune Response

A synthetic review: natural history of amniote reproductive modes in light of comparative evolutionary genomics

There is a current lack of consensus on whether the ancestral parity mode was oviparity (egg-laying) or viviparity (live-birth) in amniotes and particularly in squamates (snakes, lizards, and amphisbaenids). How transitions between parity modes occur at the genomic level has primary importance for how science conceptualises the origin of amniotes, and highly variable parity modes in Squamata. Synthesising literature from medicine, poultry science, reproductive biology, and evolutionary biology, I review the genomics and physiology of five broad processes (here termed the 'Main Five') expected to change during transitions between parity modes: eggshell formation, embryonic retention, placentation, calcium transport, and maternal-fetal immune dynamics. Throughout, I offer alternative perspectives and testable hypotheses regarding proximate causes of parity mode evolution in amniotes and squamates. If viviparity did evolve early in the history of lepidosaurs, I offer the nucleation site hypothesis as a proximate explanation. The framework of this hypothesis can be extended to amniotes to infer their ancestral state. I also provide a mechanism and hypothesis on how squamates may transition from viviparity to oviparity and make predictions about the directionality of transitions in three species. After considering evidence for differing perspectives on amniote origins, I offer a framework that unifies (i) the extended embryonic retention model and (ii) the traditional model which describes the amniote egg as an adaptation to the terrestrial environment. Additionally, this review contextualises the origin of amniotes and parity mode evolution within Medawar's paradigm. Medawar posited that pregnancy could be supported by immunosuppression, inertness, evasion, or immunological barriers. I demonstrate that this does not support gestation or gravidity across most amniotes but may be an adequate paradigm to explain how the first amniote tolerated internal fertilization and delayed egg deposition. In this context, the eggshell can be thought of as an immunological barrier. If serving as a barrier underpins the origin of the amniote eggshell, there should be evidence that oviparous gravidity can be met with a lack of immunological responses in utero. Rare examples of two species that differentially express very few genes during gravidity, suggestive of an absent immunological reaction to oviparous gravidity, are two skinks Lampropholis guichenoti and Lerista bougainvillii. These species may serve as good models for the original amniote egg. Overall, this review grounds itself in the historical literature while offering a modern perspective on the origin of amniotes. I encourage the scientific community to utilise this review as a resource in evolutionary and comparative genomics studies, embrace the complexity of the system, and thoughtfully consider the frameworks proposed.

Placental Protein 13: Vasomodulatory Effects on Human Uterine Arteries and Potential Implications for Preeclampsia

Placental protein 13 (PP13) exhibits a plasma concentration that increases gradually during normal gestation, a process that is disrupted in preeclampsia, which is characterized by elevated vascular resistance, reduced utero-placental blood flow, and intrauterine growth restriction. This study investigated PP13's role in vascular tone regulation and its molecular mechanisms. Uterine and subcutaneous arteries, isolated from both pregnant and non-pregnant women, were precontracted with the thromboxane analogue U46619 and exposed to PP13 using pressurized myography. The molecular mechanisms were further investigated, using specific inhibitors for nitric oxide synthase (L-NAME+LNNA at 10-4 M) and guanylate cyclase (ODQ at 10-5 M). The results showed that PP13 induced vasodilation in uterine arteries, but not in subcutaneous arteries. Additionally, PP13 counteracted U46619-induced vasoconstriction, which is particularly pronounced in pregnancy. Further investigation revealed that PP13's mechanism of action is dependent on the activation of the nitric oxide-cGMP pathway. This study provides novel insights into the vasomodulatory effects of PP13 on human uterine arteries, underscoring its potential role in regulating utero-placental blood flow. These findings suggest that PP13 may be a promising candidate for improving utero-placental blood flow in conditions such as preeclampsia. Further research and clinical studies are warranted to validate PP13's efficacy and safety as a therapeutic agent for managing preeclampsia.

Galectin-13 and Laeverin Levels Interfere with Human Fetoplacental Growth

Galectin-13 (Gal-13) is predominantly produced by the syncytiotrophoblast, while laeverin is expressed on the outgrowing extravillous trophoblast, and both are thought to be biomarkers of preeclampsia. The aim of this study was to assess the correlation between concentrations of Gal-13 and laeverin measured in maternal serum and amniotic fluid at 16-22 weeks of gestation and the sonographic assessment of the fetoplacental measurements. Fetal biometric data and placental volume and perfusion indices were measured in 62 singleton pregnancies. Serum and amniotic levels of Gal-13 and laeverin levels were measured using a sandwich ELISA. Both amniotic fluid and serum Gal-13 levels expressed a negative correlation to the plasma laeverin level in mid-pregnancy. Serum laeverin level correlated positively with the gestational length at delivery (β = 0.39, p < 0.05), while the amniotic laeverin level correlated well with the abdominal circumference of the fetus (β = 0.44, p < 0.05). Furthermore, laeverin level in the amnion correlated positively with the estimated fetal weight (β = 0.48, p < 0.05) and with the placental volume (β = 0.32, p < 0.05). Logistic regression analyses revealed that a higher circulating Gal-13 level represents a slightly significant risk factor (OR: 1.01) for hypertension-related diseases during pregnancy. It is a novelty that laeverin can be detected in the amniotic fluid, and amnion laeverin concentration represents a potential biomarker of fetoplacental growth.

Placental expression of inflammatory Galectin-12 is associated with gestational diabetes

OBJECTIVES

Gestational diabetes mellitus (GDM) is a growing health concern. Since members of the galectin-family are identified to play a role in the pathogenesis of GDM, we determined galectin-12 as an essential protein due to its influence in lipolysis and inflammation processes. This study investigates the expression of galectin-12 in the placentas of women with GDM.

STUDY DESIGN

The study population includes 40 expectant women suffering from GDM and 40 healthy controls. The expression of galectin-12 in the syncytiotrophoblast (SCT) and the extra villous trophoblast (EVT) of the placenta was analyzed by immunohistological staining and double immunofluorescence. Immunoreactivity Score (IRS) was used for evaluation.

RESULTS

The results demonstrate a significant overexpression of galectin-12 in the nucleus of the SCT and the EVT of placentas with GDM compared to the healthy control group. Additionally, double immunofluorescence visualizes corresponding results with an overexpression of galectin-12 in the extra villous trophoblast of GDM placentas representing maternal cells.

CONCLUSION

This study identifies galectin-12 to be associated with the process of gestational diabetes mellitus. These findings are in correspondence with the involvement of galectin-12 in inflammatory processes. Maternal BMI and male sex seem to be confounder for the expression of galectin-12 in the nuclear syncytiotrophoblast, but not in other parts of the investigated placental areas. Further investigations are necessary to verify the correlation between gestational diabetes mellitus and the expression of galectin-12 in the placenta and to further elucidate its distinct role.

Placenta: an old organ with new functions

The transition from oviparity to viviparity and the establishment of feto-maternal communications introduced the placenta as the major anatomical site to provide nutrients, gases, and hormones to the developing fetus. The placenta has endocrine functions, orchestrates maternal adaptations to pregnancy at different periods of pregnancy, and acts as a selective barrier to minimize exposure of developing fetus to xenobiotics, pathogens, and parasites. Despite the fact that this ancient organ is central for establishment of a normal pregnancy in eutherians, the placenta remains one of the least studied organs. The first step of pregnancy, embryo implantation, is finely regulated by the trophoectoderm, the precursor of all trophoblast cells. There is a bidirectional communication between placenta and endometrium leading to decidualization, a critical step for maintenance of pregnancy. There are three-direction interactions between the placenta, maternal immune cells, and the endometrium for adaptation of endometrial immune system to the allogeneic fetus. While 65% of all systemically expressed human proteins have been found in the placenta tissues, it expresses numerous placenta-specific proteins, whose expression are dramatically changed in gestational diseases and could serve as biomarkers for early detection of gestational diseases. Surprisingly, placentation and carcinogenesis exhibit numerous shared features in metabolism and cell behavior, proteins and molecular signatures, signaling pathways, and tissue microenvironment, which proposes the concept of "cancer as ectopic trophoblastic cells". By extensive researches in this novel field, a handful of cancer biomarkers has been discovered. This review paper, which has been inspired in part by our extensive experiences during the past couple of years, highlights new aspects of placental functions with emphasis on its immunomodulatory role in establishment of a successful pregnancy and on a potential link between placentation and carcinogenesis.

Decreased Expression of Placental Proteins in Recurrent Pregnancy Loss: Functional Relevance and Diagnostic Value

Miscarriages affect 50-70% of all conceptions and 15-20% of clinically recognized pregnancies. Recurrent pregnancy loss (RPL, ≥2 miscarriages) affects 1-5% of recognized pregnancies. Nevertheless, our knowledge about the etiologies and pathophysiology of RPL is incomplete, and thus, reliable diagnostic/preventive tools are not yet available. Here, we aimed to define the diagnostic value of three placental proteins for RPL: human chorionic gonadotropin free beta-subunit (free-β-hCG), pregnancy-associated plasma protein-A (PAPP-A), and placental growth factor (PlGF). Blood samples were collected from women with RPL (n = 14) and controls undergoing elective termination of pregnancy (n = 30) at the time of surgery. Maternal serum protein concentrations were measured by BRAHMS KRYPTOR Analyzer. Daily multiple of median (dMoM) values were calculated for gestational age-specific normalization. To obtain classifiers, logistic regression analysis was performed, and ROC curves were calculated. There were differences in changes of maternal serum protein concentrations with advancing healthy gestation. Between 6 and 13 weeks, women with RPL had lower concentrations and dMoMs of free β-hCG, PAPP-A, and PlGF than controls. PAPP-A dMoM had the best discriminative properties (AUC = 0.880). Between 9 and 13 weeks, discriminative properties of all protein dMoMs were excellent (free β-hCG: AUC = 0.975; PAPP-A: AUC = 0.998; PlGF: AUC = 0.924). In conclusion, free-β-hCG and PAPP-A are valuable biomarkers for RPL, especially between 9 and 13 weeks. Their decreased concentrations indicate the deterioration of placental functions, while lower PlGF levels indicate problems with placental angiogenesis after 9 weeks.

Placental galectins: a subfamily of galectins lose the ability to bind β-galactosides with new structural features†

Galectins are a phylogenetically conserved family of soluble β-galactoside binding proteins. There are 16 different of galectins, each with a specific function determined by its distinct distribution and spatial structure. Galectin-13, galectin-14, and galectin-16 are distinct from other galectin members in that they are primarily found in placental tissue. These galectins, also referred to as placental galectins, play critical roles in regulating pregnancy-associated processes, such as placenta formation and maternal immune tolerance to the embedded embryo. The unique structural characteristics and the inability to bind lactose of placental galectins have recently received significant attention. This review primarily examines the novel structural features of placental galectins, which distinguish them from the classic galectins. Furthermore, it explores the correlation between these structural features and the loss of β-galactoside binding ability. In addition, the newly discovered functions of placental galectins in recent years are also summarized in our review. A detailed understanding of the roles of placental galectins may contribute to the discovery of new mechanisms causing numerous pregnancy diseases and enable the development of new diagnostic and therapeutic strategies for the treatment of these diseases, ultimately benefiting the health of mothers and offspring.

A pattern recognition receptor C-type lectin TcCTL14 contributes to immune response and development in the red flour beetle, Tribolium castaneum

Evidence is accumulating that pattern recognition receptor (PRR) C-type lectins (CTL) play essential roles in recognition of pathogens. TcCTL14 (accession no. TC00871) contains the most domains among all CTL of Tribolium castaneum. Yet the biological function of TcCTL14 remains unclear. In this study, TcCTL14 exhibiting typical motif and domain of CTL was cloned from T. castaneum. The expression pattern analysis showed that TcCTL14 was highly expressed in late pupae and central nervous system, and was upregulated after treatment with Escherichia coli and Staphylococcus aureus, respectively. Analysis of binding affinity revealed that recombinant TcCTL14 not only could bind to lipopolysaccharide and peptidoglycan in a dose-dependent fashion, but possibly could bind to and agglutinate different bacteria in a Ca2+ -dependent fashion. Knockdown of TcCTL14 before injection with bacteria led to the downregulation of nuclear factor-κB transcription factors of Toll/IMD and 4 antimicrobial peptides. Knockdown of TcCTL14 also caused suppressed metamorphosis, reduced fecundity, and delayed embryogenesis of T. castaneum. Further observation discovered that knockdown of TcCTL14 inhibited the development of ovaries and embryos. The detection of signaling pathways revealed that TcCTL14 may be involved in metamorphosis and fecundity by impacting 20-hydroxyecdysone and vitellogenin, respectively. Overall, these results indicate that TcCTL14 may contribute to immune response by agglutination or regulating the expression of antimicrobial peptides by the Toll/IMD pathway, and is required for T. castaneum development including metamorphosis, fecundity, and embryogenesis. These findings will improve the functional cognition of PRR CTL in insects and provide the new strategy for pest control.

Intronic variants of LGALS13 gene encoding placental protein (PP13) are linked with increased risk of infection-associated spontaneous preterm birth

PROBLEM

Spontaneous preterm birth (sPTB) is a global health issue. Studies suggest infection and infection-based inflammatory responses are major risk factors for sPTB. Considering the important role of anti-inflammatory proteins in pregnancy, the study aimed to find the association between anti-inflammatory LGALS13 gene variants IVS2-22 A/G (rs2233706) and IVS3+72 T/A (rs2233708) and the risk of sPTB during Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum infection in Indian population.

METHOD OF STUDY

Placental samples of 160 sPTB and 160 term women were collected. Pathogens were detected by PCR. The genotyping of LGALS13 gene variants IVS2-22 A/G (rs2233706) and IVS3+72 T/A (rs2233708) was done by qualitative real-time PCR using allelic discrimination method (VIC- and FAM-labeled).

RESULTS

The frequency of AG or GG genotype of LGALS13 IVS2-22A/G polymorphism (rs2233706) was 75.5% in infected sPTB cases and 14.4% in uninfected sPTB cases and 7.3% in term birth controls (p < .0001), while the frequency of TA or AA genotype of LGALS13 IVS3+72T/A polymorphism (rs2233708) was 83.6% in infected sPTB cases and 18% in uninfected sPTB cases and 12.7% in term birth controls (p < .0001). The genotypic frequencies for both the variants of LGALS13 were statistically significant (p < .0001) in the infected sPTB versus uninfected sPTB and term birth controls.

CONCLUSIONS

Study reveals strong association between the presence of immunological gene variants LGALS13 IVS2-22 A/G (rs2233706) and LGALS13 IVS3+72 T/A (rs2233708) and risk of sPTB during C. trachomatis, M. hominis and U. urealyticum infection.

Genome-Wide Re-Sequencing Data Reveals the Population Structure and Selection Signatures of Tunchang Pigs in China

Tunchang pig is one population of Hainan pig in the Hainan Province of China, with the characteristics of delicious meat, strong adaptability, and high resistance to diseases. To explore the genetic diversity and population structure of Tunchang pigs and uncover their germplasm characteristics, 10 unrelated Tunchang pigs were re-sequenced using the Illumina NovaSeq 150 bp paired-end platform with an average depth of 10×. Sequencing data from 36 individuals of 7 other pig breeds (including 4 local Chinese pig breeds (5 Jinhua, 5 Meishan, 5 Rongchang, and 6 Wuzhishan), and 3 commonly used commercial pig breeds (5 Duorc, 5 Landrace, and 5 Large White)) were downloaded from the NCBI public database. After analysis of genetic diversity and population structure, it has been found that compared to commercial pigs, Tunchang pigs have higher genetic diversity and are genetically close to native Chinese breeds. Three methods, FST, θπ, and XP-EHH, were used to detect selection signals for three breeds of pigs: Tunchang, Duroc, and Landrace. A total of 2117 significantly selected regions and 201 candidate genes were screened. Gene enrichment analysis showed that candidate genes were mainly associated with good adaptability, disease resistance, and lipid metabolism traits. Finally, further screening was conducted to identify potential candidate genes related to phenotypic traits, including meat quality (SELENOV, CBR4, TNNT1, TNNT3, VPS13A, PLD3, SRFBP1, and SSPN), immune regulation (CD48, FBL, PTPRH, GNA14, LOX, SLAMF6, CALCOCO1, IRGC, and ZNF667), growth and development (SYT5, PRX, PPP1R12C, and SMG9), reproduction (LGALS13 and EPG5), vision (SLC9A8 and KCNV2), energy metabolism (ATP5G2), cell migration (EPS8L1), and olfaction (GRK3). In summary, our research results provide a genomic overview of the genetic variation, genetic diversity, and population structure of the Tunchang pig population, which will be valuable for breeding and conservation of Tunchang pigs in the future.

Chimera and Tandem-Repeat Type Galectins: The New Targets for Cancer Immunotherapy

In humans, a total of 12 galectins have been identified. Their intracellular and extracellular biological functions are explored and discussed in this review. These galectins play important roles in controlling immune responses within the tumour microenvironment (TME) and the infiltration of immune cells, including different subsets of T cells, macrophages, and neutrophils, to fight against cancer cells. However, these infiltrating cells also have repair roles and are hijacked by cancer cells for pro-tumorigenic activities. Upon a better understanding of the immunomodulating functions of galectin-3 and -9, their inhibitors, namely, GB1211 and LYT-200, have been selected as candidates for clinical trials. The use of these galectin inhibitors as combined treatments with current immune checkpoint inhibitors (ICIs) is also undergoing clinical trial investigations. Through their network of binding partners, inhibition of galectin have broad downstream effects acting on CD8⁺ cytotoxic T cells, regulatory T cells (Tregs), Natural Killer (NK) cells, and macrophages as well as playing pro-inflammatory roles, inhibiting T-cell exhaustion to support the fight against cancer cells. Other galectin members are also included in this review to provide insight into potential candidates for future treatment(s). The pitfalls and limitations of using galectins and their inhibitors are also discussed to cognise their clinical application.

Perturbations in kinetics of the thrombin generation assay identify women at risk of preeclampsia in the first trimester and provide the rationale for a preventive approach

BACKGROUND

Activation of the coagulation system and increased thrombin generation have been implicated in the pathophysiology of preeclampsia, and this rationale supports the administration of low-molecular-weight heparin to prevent this syndrome in patients at risk. Yet, randomized trials of this prophylactic measure have yielded contradictory results. A possible explanation is that only a subset of patients with preeclampsia have excessive thrombin generation and would benefit from the administration of low-molecular-weight heparin. Therefore, the key questions are whether and when patients who subsequently develop preeclampsia present evidence of abnormal thrombin generation.

OBJECTIVE

This study aimed to determine (1) the kinetics of thrombin generation throughout gestation in women with a normal pregnancy and in those with early and late preeclampsia, and (2) the diagnostic performance of in vivo thrombin generation parameters to predict the development of preeclampsia.

STUDY DESIGN

This retrospective, nested case-control study was based on a prospective longitudinal cohort of singleton gestations. Cases comprised women who developed preeclampsia (n=49), and controls consisted of patients with a normal pregnancy (n=45). Preeclampsia was classified into early-onset (n=24) and late-onset (n=25). Longitudinal changes in the parameters of the thrombin generation assay (lag time, time to peak thrombin concentration, peak thrombin concentration, endogenous thrombin generation, and velocity index) throughout gestation were compared between the study groups, and normal pregnancy percentiles were derived from the control group. We tested whether a single parameter or a combination of parameters, derived from the kinetics of thrombin generation, could identify patients who subsequently developed preeclampsia. Time-related parameters <10th percentile were considered short, and concentration-related parameters >90th percentile were considered high.

RESULTS

(1) Patients who developed preeclampsia (early- and late-onset) had abnormal thrombin generation kinetics as early as 8 to 16 weeks of pregnancy; (2) patients with a combination of a short lag time and high peak thrombin concentration at 8 to 16 weeks of pregnancy had an odds ratio of 43.87 for the subsequent development of preeclampsia (area under the curve, 0.79; sensitivity, 56.8%; specificity, 92.7%; positive likelihood ratio, 7.76); (3) at 16 to 22 weeks of gestation, patients with a combination of a short lag time and a high velocity index had an odds ratio of 16 for the subsequent development of preeclampsia (area under the curve, 0.78; sensitivity, 62.2%; specificity, 92.5%; positive likelihood ratio, 8.29).

CONCLUSION

During early pregnancy, the thrombin generation assay can identify the subset of patients at a greater risk for the development of preeclampsia owing to accelerated and enhanced production of thrombin. This observation provides a rationale for testing the efficacy of low-molecular-weight heparin in this subset of patients. We propose that future research on the efficacy of low-molecular-weight heparin and other interventions targeting the coagulation system to prevent preeclampsia should be focused on patients with abnormal kinetics of thrombin generation.

Galectins are critical regulators of cytokine signalling at feto-maternal interface in infection-associated spontaneous preterm birth

INTRODUCTION

Spontaneous preterm birth (sPTB) is a global health issue. Studies suggest infections are chiefly associated with sPTB and galectins (gals) play a role in regulation of innate and adaptive maternal immune response against pathogens during sPTB. The aim of this study was to describe the gene expression of gal -1, -3, -8, -9, -13 in relation to gene expression of cyclooxygenase-2 (COX-2) and the cytokines IL-8, IL-10, TNF-α, IFN-ϒ in the setting of sPTB and confirmed infection with Chlamydia trachomatis, Mycoplasma hominis, and Ureaplasma urealyticum.

METHODS

Placental samples were collected from 120 term control and 120 sPTB pregnancies. PCR was used to detect specific pathogens. Gene expression of galectins, cytokines, and COX-2 was performed using real time qPCR.

RESULTS

Fold-change expression of gal -1, -3, -8, -9, -13 was 5.13, 6.11, 1.14, 5.23 and 7.16 (p<0.001), respectively; while IL-10, IL-8, TNF-α, IFN-ϒ and COX-2 was 6.29, 6.55, 6.35, 6.36 and 2.73-fold upregulated (p<0.05), respectively in infected sPTB. Gal-1 was positively correlated with IL-10 (r=0.49, p=0.003) while gal-3 showed significant correlation with IL-8 (r=0.42, p=0.0113), TNF-α (r=0.65, p=< 0.001) and COX-2 (r=0.72, p=0.001). However, gal-8 was not significantly correlated with any cytokine. Gal-9, -13 were negatively correlated with IFN-ϒ (r=-0.45, p=0.006) and IL-8 (r=-0.39, p=0.018).

DISCUSSION

Gal-1, -9, -13 are anti-inflammatory and might play role in immune-tolerance while gal-3 is pro-inflammatory and possibly responsible for immunogenic response, having potential to anticipate the clinical beginning of preterm labour during infection.

Roles of N-linked glycosylation and glycan-binding proteins in placentation: trophoblast infiltration, immunomodulation, angiogenesis, and pathophysiology

Protein N-linked glycosylation is a structurally diverse post-translational modification that stores biological information in a larger order of magnitude than other post-translational modifications such as phosphorylation, ubiquitination and acetylation. This gives N-glycosylated proteins a diverse range of properties and allows glyco-codes (glycan-related information) to be deciphered by glycan-binding proteins (GBPs). The intervillous space of the placenta is richly populated with membrane-bound and secreted glycoproteins. Evidence exists to suggest that altering the structural nature of their N-glycans can impact several trophoblast functions, which include those related to interactions with decidual cells. This review summarizes trophoblast-related activities influenced by N-glycan-GBP recognition, exploring how different subtypes of trophoblasts actively adapt to characteristics of the decidualized endometrium through cell-specific expression of N-glycosylated proteins, and how these cells receive decidua-derived signals via N-glycan-GBP interactions. We highlight work on how changes in N-glycosylation relates to the success of trophoblast infiltration, interactions of immunomodulators, and uterine angiogenesis. We also discuss studies that suggest aberrant N-glycosylation of trophoblasts may contribute to the pathogenesis of pregnancy complications (e.g. pre-eclampsia, early spontaneous miscarriages and hydatidiform mole). We propose that a more in-depth understanding of how N-glycosylation shapes trophoblast phenotype during early pregnancy has the potential to improve our approach to predicting, diagnosing and alleviating poor maternal/fetal outcomes associated with placental dysfunction.

A C-type lectin TcCTL1 is required for embryogenesis in Tribolium castaneum

C-type lectin S group (CTL-S) plays a variety of roles in invertebrate including pathogen recognition and activation of immune responses. Previous studies have shown that CTL-S subfamily of Tribolium castaneum is mainly divided into two clades, of which only TcCTL1 was separately located in one clade. However, it remains unclear whether TcCTL1 occurs the differentiation of function. Therefore, the CTL-S TcCTL1 gene was cloned and characterized from T. castaneum. Functional analysis revealed that TcCTL1 could recognize and agglutinate pathogens, as well as activate immune signaling pathways to participate in immune response, which was consistent with our previously reported for TcCTL5 and TcCTL6. Differently, RNAi of TcCTL1 discovered that the egg produced by dsTcCTL1-treated adult could not hatch into larvae. Further DAPI-straining embryo indicated that the process of embryogenesis in dsTcCTL1-treated beetle was defeated, implying that TcCTL1 is required for embryogenesis in T. castaneum except for immune response. These results will aid implications for the understanding of CTL-S in invertebrate.

Placental Galectins in Cancer: Why We Should Pay More Attention

The first studies suggesting that abnormal expression of galectins is associated with cancer were published more than 30 years ago. Today, the role of galectins in cancer is relatively well established. We know that galectins play an active role in many types of cancer by regulating cell growth, conferring cell death resistance, or inducing local and systemic immunosuppression, allowing tumor cells to escape the host immune response. However, most of these studies have focused on very few galectins, most notably galectin-1 and galectin-3, and more recently, galectin-7 and galectin-9. Whether other galectins play a role in cancer remains unclear. This is particularly true for placental galectins, a subgroup that includes galectin-13, -14, and -16. The role of these galectins in placental development has been well described, and excellent reviews on their role during pregnancy have been published. At first sight, it was considered unlikely that placental galectins were involved in cancer. Yet, placentation and cancer progression share several cellular and molecular features, including cell invasion, immune tolerance and vascular remodeling. The development of new research tools and the concomitant increase in database repositories for high throughput gene expression data of normal and cancer tissues provide a new opportunity to examine the potential involvement of placental galectins in cancer. In this review, we discuss the possible roles of placental galectins in cancer progression and why they should be considered in cancer studies. We also address challenges associated with developing novel research tools to investigate their protumorigenic functions and design highly specific therapeutic drugs.

Galectin functions in cancer-associated inflammation and thrombosis

Galectins are carbohydrate-binding proteins that regulate many cellular functions including proliferation, adhesion, migration, and phagocytosis. Increasing experimental and clinical evidence indicates that galectins influence many steps of cancer development by inducing the recruitment of immune cells to the inflammatory sites and modulating the effector function of neutrophils, monocytes, and lymphocytes. Recent studies described that different isoforms of galectins can induce platelet adhesion, aggregation, and granule release through the interaction with platelet-specific glycoproteins and integrins. Patients with cancer and/or deep-venous thrombosis have increased levels of galectins in the vasculature, suggesting that these proteins could be important contributors to cancer-associated inflammation and thrombosis. In this review, we summarize the pathological role of galectins in inflammatory and thrombotic events, influencing tumor progression and metastasis. We also discuss the potential of anti-cancer therapies targeting galectins in the pathological context of cancer-associated inflammation and thrombosis.

Placental galectins regulate innate and adaptive immune responses in pregnancy

Introduction

Galectins are master regulators of maternal immune responses and placentation in pregnancy. Galectin-13 (gal-13) and galectin-14 (gal-14) are expressed solely by the placenta and contribute to maternal-fetal immune tolerance by inducing the apoptosis of activated T lymphocytes and the polarization of neutrophils toward an immune-regulatory phenotype.Furthermore, their decreased placental expression is associated with pregnancy complications, such as preeclampsia and miscarriage. Yet, our knowledge of the immunoregulatory role of placental galectins is incomplete.

Methods

This study aimed to investigate the effects of recombinant gal-13 and gal-14 on cell viability, apoptosis, and cytokine production of peripheral blood mononuclear cells (PBMCs) and the signaling pathways involved.

Results

Herein, we show that gal-13 and gal-14 bind to the surface of non-activated PBMCs (monocytes, natural killer cells, B cells, and T cells) and increase their viability while decreasing the rate of their apoptosis without promoting cell proliferation. We also demonstrate that gal-13 and gal-14 induce the production of interleukin (IL)-8, IL-10, and interferon-gamma cytokines in a concentration-dependent manner in PBMCs. The parallel activation of Erk1/2, p38, and NF-ĸB signaling evidenced by kinase phosphorylation in PBMCs suggests the involvement of these pathways in the regulation of the galectin-affected immune cell functions.

Discussion

These findings provide further evidence on how placenta-specific galectins assist in the establishment and maintenance of a proper immune environment during a healthy pregnancy.

Galectins: Important Regulators in Normal and Pathologic Pregnancies

Galectins (Gal) are characterized by their affinity for galactoside structures on glycoconjugates. This relationship is mediated by carbohydrate recognition domains, which are multifunctional regulators of basic cellular biological processes with high structural similarity among family members. They participate in both innate and adaptive immune responses, as well as in reproductive immunology. Recently, the discovery that galectins are highly expressed at the maternal–fetal interface has garnerd the interest of experts in human reproduction. Galectins are involved in a variety of functions such as maternal–fetal immune tolerance, angiogenesis, trophoblast invasion and placental development and are considered to be important mediators of successful embryo implantation and during pregnancy. Dysregulation of these galectins is associated with abnormal and pathological pregnancies (e.g., preeclampsia, gestational diabetes mellitus, fetal growth restriction, preterm birth). Our work reviews the regulatory mechanisms of galectins in normal and pathological pregnancies and has implications for clinicians in the prevention, diagnosis and treatment of pregnancy-related diseases.

Seminal Plasma Glycoproteins as Potential Ligands of Lectins Engaged in Immunity Regulation

Environmental pollution, chronic stress, and unhealthy lifestyle are factors that negatively affect reproductive potential. Currently, 15-20% of couples in industrialized countries face the problem of infertility. This growing health and social problem prompts researchers to explore the regulatory mechanisms that may be important for successful fertilization. In recent years, more attention has been paid to male infertility factors, including the impact of seminal plasma components on regulation of the female immune response to allogenic sperm, embryo and fetal antigens. Directing this response to the tolerogenic pathway is crucial to achieve a healthy pregnancy. According to the fetoembryonic defense hypothesis, the regulatory mechanism may be associated with the interaction of lectins and immunomodulatory glycoepitopes. Such interactions may involve lectins of dendritic cells and macrophages, recruited to the cervical region immediately after intercourse. Carbohydrate binding receptors include C type lectins, such as DC-SIGN and MGL, as well as galectins and siglecs among others. In this article we discuss the expression of the possible lectin ligands, highly fucosylated and high mannose structures, which may be recognized by DC-SIGN, glycans of varying degrees of sialylation, which may differ in their interaction with siglecs, as well as T and Tn antigens in O-glycans.

Possible important roles of galectins in the healing of human fetal membranes

The fetal membranes healing is a complex and dynamic process of replacing devitalized and missing cellular structures and tissue layers. Multiple cells and extracellular matrices, and cell differentiation, migration and proliferation may participate in restoring the integrity of damaged tissue, however this process still remains unclear. Therefore, there is a need to identify and integrate new ideas and methods to design a more effective dressing to accelerate fetal membrane healing. This review explores the function and role of galectins in the inflammatory, epithelial mesenchymal transition, proliferative migration, and remodeling phases of fetal membrane healing. In conclusion, the preliminary findings are promising. Research on amnion regeneration is expected to provide insight into potential treatment strategies for premature rupture of membranes.

How trophoblasts fuse: an in-depth look into placental syncytiotrophoblast formation

In humans, cell fusion is restricted to only a few cell types under normal conditions. In the placenta, cell fusion is a critical process for generating syncytiotrophoblast: the giant multinucleated trophoblast lineage containing billions of nuclei within an interconnected cytoplasm that forms the primary interface separating maternal blood from fetal tissue. The unique morphology of syncytiotrophoblast ensures that nutrients and gases can be efficiently transferred between maternal and fetal tissue while simultaneously restricting entry of potentially damaging substances and maternal immune cells through intercellular junctions. To maintain integrity of the syncytiotrophoblast layer, underlying cytotrophoblast progenitor cells terminate their capability for self-renewal, upregulate expression of genes needed for differentiation, and then fuse into the overlying syncytium. These processes are disrupted in a variety of obstetric complications, underscoring the importance of proper syncytiotrophoblast formation for pregnancy health. Herein, an overview of key mechanisms underlying human trophoblast fusion and syncytiotrophoblast development is discussed.

Placental protein 13 dilation of pregnant rat uterine vein is endothelium dependent and involves nitric oxide/calcium activated potassium channels signals

INTRODUCTION

Accumulating evidence demonstrates the importance of the galectin protein Placental Protein 13 (PP13) in predicting Preeclampsia (PE), a gestational disorder that has no cure and is associated with a compromised uterine vascular adaptation to pregnancy. Uterine vasculature undergoes significant remodeling (growth in length and in circumference) during normal pregnancy to accommodate the increased blood volume to the feto-placental unit. The aim of this study was to demonstrate the role of PP13 on the uterine veins (UVs).

METHODS

PP13 was tested on UVs isolated from rat by using a pressurized myograph. The PP13 investigation was carried out in the presence of: a) nitric oxide synthases inhibitors (l-NAME + L-NNA, 2 x 10^-4 M); b) small conductance Ca²⁺-activated K⁺ channels (SK_ca) inhibitor (Apamin, 10^-7 M); c) intermediate conductance Ca²⁺-activated K⁺ channels (IK_ca) inhibitor (TRAM-34, 10^-5 M); d) big conductance Ca²⁺-activated K⁺ channels (BK_ca) inhibitor (Paxilline, 10^-5 M) and in the absence of endothelium.

RESULTS

Our results showed that in late pregnancy, PP13 induced a significant dilation of UVs that is endothelium dependent. Further, PP13-dilation is mediated by the SKca - NO - BKca pathway.

DISCUSSION

For the first time, this study provides evidence that in pregnancy, the UVs are dilated by PP13 and suggests SK_Ca as a potential target for treatments aimed at restoring pregnancy complication associated with deficiency in uterine adaptation.

Chromosomal Copy Number Variation Analysis in Pregnancy Products from Recurrent and Sporadic Miscarriage Using Next-Generation Sequencing

Chromosomal abnormality is one of the causes of fetal miscarriage. The potential differences of fetal chromosomal abnormalities in sporadic miscarriage (SM) and recurrent miscarriage (RM) remain unclear. The purpose of this study was to investigate copy number variations (CNVs) in SM and RM to provide useful genetic guidance for pregnancy and prenatal diagnosis. Four hundred eight samples of aborted fetuses were analyzed by CNV sequencing, and further functional enrichment analysis was performed. Chromosomal abnormalities were identified in 218 (53.4%) fetuses. There were 62 cases (15.2%) with structural chromosomal abnormalities, including 41 with VUS CNVs, 8 with pathogenic CNVs (pCNVs), and 5 with likely pCNVs. Duplications or deletions of 7p22, 8p22, 8p23, and Xp22.31 were significantly more common in RM cases and therefore believed to be related to RM. A total of 289 genes were identified, and 29 different functions were enriched as potential RM candidate genes and functions, which were mainly concentrated in 4 functional categories: chemokines and chemotaxis, protease activity and protein modification, defense response to bacterial and fungal infections, and immune response. The results of this study may improve our understanding of the etiology of RM and contribute to the establishment of a population-based genetic marker information for RM.

Evaluating the Effects of BPA and TBBPA Exposure on Pregnancy Loss and Maternal-Fetal Immune Cells in Mice

BACKGROUND

Bisphenol A (BPA) exposure has been linked to miscarriages and pregnancy complications in humans. In contrast, the potential reproductive toxicity of BPA analogs, including tetrabromobisphenol A (TBBPA), is understudied. Furthermore, although environmental exposure has been linked to altered immune mediators, the effects of BPA and TBBPA on maternal-fetal immune tolerance during pregnancy have not been studied. The present study investigated whether exposure resulted in higher rates of pregnancy loss in mice, lower number of regulatory T cells (Tregs), and lower indoleamine 2,3 deoxygenase 1 (Ido1) expression, which provided evidence for mechanisms related to immune tolerance in pregnancy.

OBJECTIVES

The purpose of this investigation was to characterize the effects of BPA and TBBPA exposure on pregnancy loss in mice and to study the percentage and number of Tregs and Ido1 expression and DNA methylation.

METHODS

Analysis of fetal resorption and quantification of maternal and fetal immune cells by flow cytometry were performed in allogeneic and syngeneic pregnancies. Ido1 mRNA and protein expression, and DNA methylation in placentas from control and BPA- and TBBPA-exposed mice were analyzed using real-time quantitative polymerase chain reaction, immunofluorescence, and bisulfite sequencing analyses.

RESULTS

BPA and TBBPA exposure resulted in higher rates of hemorrhaging in early allogeneic, but not syngeneic, conceptuses. In allogeneic pregnancies, BPA and TBBPA exposure was associated with higher fetal resorption rates and lower maternal Treg number. Importantly, these differences were associated with lower IDO1 protein expression in trophoblast giant cells and higher mean percentage Ido1 DNA methylation in embryonic day 9.5 placentas from BPA- and TBBPA-exposed mice.

DISCUSSION

BPA- and TBBPA-induced pregnancy loss in mice was associated with perturbed IDO1-dependent maternal immune tolerance. https://doi.org/10.1289/EHP10640.

Medawar's PostEra: Galectins Emerged as Key Players During Fetal-Maternal Glycoimmune Adaptation

Lectin-glycan interactions, in particular those mediated by the galectin family, regulate many processes required for a successful pregnancy. Over the past decades, increasing evidence gathered from in vitro and in vivo experiments indicate that members of the galectin family specifically bind to both intracellular and membrane bound carbohydrate ligands regulating angiogenesis, immune-cell adaptations required to tolerate the fetal semi-allograft and mammalian embryogenesis. Therefore, galectins play important roles in fetal development and placentation contributing to maternal and fetal health. This review discusses the expression and role of galectins during the course of pregnancy, with an emphasis on maternal immune adaptions and galectin-glycan interactions uncovered in the recent years. In addition, we summarize the galectin fingerprints associated with pathological gestation with particular focus on preeclampsia.

Galectins in Early Pregnancy and Pregnancy-Associated Pathologies

Galectins are a family of conserved soluble proteins defined by an affinity for β-galactoside structures present on various glycoconjugates. Over the past few decades, galectins have been recognized as important factors for successful implantation and maintenance of pregnancy. An increasing number of studies have demonstrated their involvement in trophoblast cell function and placental development. In addition, several lines of evidence suggest their important roles in feto-maternal immune tolerance regulation and angiogenesis. Changed or dysregulated galectin expression is also described in pregnancy-related disorders. Although the data regarding galectins' clinical relevance are still at an early stage, evidence suggests that some galectin family members are promising candidates for better understanding pregnancy-related pathologies, as well as predicting biomarkers. In this review, we aim to summarize current knowledge of galectins in early pregnancy as well as in pregnancy-related pathologies.

Predictive Performance of Placental Protein 13 for Screening Preeclampsia in the First Trimester: A Systematic Review and Meta-Analysis

Preeclampsia is a pregnancy-specific syndrome that affects maternal and neonatal mortality. Several serum biomarkers can be used to predict preeclampsia. Among these proteins, placental protein 13 (PP13) has received progressively more interest in recent studies. The decrease in PP13 expression is one of the earliest signs for the development of preeclampsia and has shown its predictive performance for preeclampsia. In this meta-analysis, we collected 17 observational studies with 40,474 pregnant women. The overall sensitivity of PP13 to predict preeclampsia was 0.62 [95% confidence interval (CI) = 0.49–0.74], the specificity was 0.84 (95%CI = 0.81–0.86), and the diagnostic odds ratio was nine (95%CI = 5–15). The area under the curve for summary receiver operating characteristic was 0.84. We then chose the early-onset preeclampsia as a subgroup. The sensitivity of early-onset subgroup was 0.63 (95%CI = 0.58–0.76), the specificity was 0.85 (95%CI = 0.82–0.88), and the diagnostic odds ratio was 10 (95%CI = 6–18). The findings of our meta-analysis indicate that PP13 may be an effective serum biomarker for the predictive screening of preeclampsia. Nonetheless, large prospective cohort studies and randomized controlled trials are expected to uncover its application in clinical practice. The heterogeneity of the original trials may limit the clinical application of PP13.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=188948 The meta-analysis was registered in PROSPERO (CRD42020188948).

Neutrophils in pregnancy: New insights into innate and adaptive immune regulation

The immunology of pregnancy has been the focus of many studies to better understand how the mother is able to tolerate the presence of a semi-allogeneic fetus. Far from the initial view of pregnancy as a state of immunosuppression, successful fetal development from implantation to birth is now known to be under the control of an intricate balance of immune cells. The balance between pro-inflammatory functions used to promote embryo implantation and placental development and immunosuppressive activity to maintain maternal tolerance of the fetus is an immunological phenotype unique to pregnancy, which is dependent on the time of gestation. Neutrophils are one of a host of innate immune cells detected at the maternal-fetal interface, but very little is known of their function. In this review, we explore the emerging functions of neutrophils during pregnancy and their interactions with and regulation of T cells, a key adaptive immune cell population essential for the establishment of fetal-maternal tolerance.

Different immunoregulatory components at the decidua basalis of oocyte donation pregnancies

Oocyte donation (OD) pregnancies are characterized by more fetal-maternal human leukocyte antigen (HLA) mismatches compared with naturally conceived (NC) and in vitro fertilization (IVF) pregnancies. The maternal immune system has to cope with greater immunogenetic dissimilarity, but involved immunoregulation remains poorly understood. We examined whether the amount of regulatory T cells (Tregs) and immunoregulatory cytokines in decidua basalis of OD pregnancies differs from NC and IVF pregnancies. The cohort included 25 OD, 11 IVF and 16 NC placentas, maternal peripheral blood, and umbilical cord blood of uncomplicated pregnancies. Placenta slides were stained for FOXP3, IL-10, IL-6, gal-1, TGF-β and Flt-1. Semi-quantitative (FOXP3+ Tregs) and computerized analysis (cytokines) were executed. The blood samples were typed for HLA class I and II to calculate fetal-maternal HLA mismatches. The percentage of Tregs was significantly higher in pregnancies with 4-6 HLA class I mismatches (n = 17), compared to 0-3 mismatches (n = 35; p = 0.04). Cytokine analysis showed significant differences between OD, IVF and NC pregnancies. Flt-1 was significantly lower in pregnancies with 4-6 HLA class I mismatches (p = 0.004), and in pregnancies with 6-10 HLA mismatches in total (p = 0.024). This study suggests that immunoregulation at the fetal-maternal interface in OD pregnancies with more fetal-maternal HLA mismatches is altered.

BCG-trained innate immunity leads to fetal growth restriction by altering immune cell profile in the mouse developing placenta

Trained immunity is a new concept illustrating that innate immune cells are able to undergo a long-term metabolic and epigenetic reprogramming after infection or vaccination, thus displaying either a pro- or an anti-inflammatory phenotype during a sequential unrelated challenge. Innate immune cells such as natural killer (NK) cells and macrophages constitute a large part of the decidual leukocyte population at the maternal-fetal interface, playing an important role in placental development and as such in fetal growth and development. In this study, we hypothesized that training the innate immune cells before pregnancy could have an impact on pregnancy. To test this hypothesis, we used CBA/J x DBA/2 mouse model to investigate pregnancy outcomes and leukocyte population at the maternal-fetal interface. Although we were not able to show a beneficial effect of LPS-tolerogenic training on fetal resorption, Bacillus Calmette-Guérin (BCG) training, known to prime innate immune cells to be proinflammatory, led to fetal growth restriction, without aggravating the fetal resorption rate. We also found that BCG training led to less NK cells and macrophages at the maternal-fetal interface at the early stage of placentation (E9.5), associated with a down-regulation of Ccr3 and Lif mRNA expression. This induced altered leucocyte population profile can be an explanation for the subsequent fetal growth restriction. These data suggest that preconceptional infections-induced trained immunity could influence pregnancy outcomes.

Reduced Placental CD24 in Preterm Preeclampsia Is an Indicator for a Failure of Immune Tolerance

INTRODUCTION

CD24 is a mucin-like glycoprotein expressed at the surface of hematopoietic and tumor cells and was recently shown to be expressed in the first trimester placenta. As it was postulated as an immune suppressor, CD24 may contribute to maternal immune tolerance to the growing fetus. Preeclampsia (PE), a major pregnancy complication, is linked to reduced immune tolerance. Here, we explored the expression of CD24 in PE placenta in preterm and term cases.

METHODS

Placentas were derived from first and early second trimester social terminations (N = 43), and third trimester normal term delivery (N = 67), preterm PE (N = 18), and preterm delivery (PTD) (N = 6). CD24 expression was determined by quantitative polymerase chain reaction (qPCR) and Western blotting. A smaller cohort included 3-5 subjects each of term and early PE, and term and preterm delivery controls analyzed by immunohistochemistry.

RESULTS

A higher expression (2.27-fold) of CD24 mRNA was determined in the normal term delivery compared to first and early second trimester cases. The mRNA of preterm PE cases was only higher by 1.31-fold compared to first and early second trimester, while in the age-matched PTD group had a fold increase of 5.72, four times higher compared to preterm PE. The delta cycle threshold (ΔCt) of CD24 mRNA expression in the preterm PE group was inversely correlated with gestational age (r = 0.737) and fetal size (r = 0.623), while correlation of any other group with these parameters was negligible. Western blot analysis revealed that the presence of CD24 protein in placental lysate of preterm PE was significantly reduced compared to term delivery controls (p = 0.026). In immunohistochemistry, there was a reduction of CD24 staining in villous trophoblast in preterm PE cases compared to gestational age-matched PTD cases (p = 0.042). Staining of PE cases at term was approximately twice higher compared to preterm PE cases (p = 0.025) but not different from normal term delivery controls.

CONCLUSION

While higher CD24 mRNA expression levels were determined for normal term delivery compared to earlier pregnancy stages, this expression level was found to be lower in preterm PE cases, and could be said to be linked to reduced immune tolerance in preeclampsia.

Cell dynamics in human villous trophoblast

BACKGROUND

Villous cytotrophoblast (vCTB) is a precursor cell population that supports the development of syncytiotrophoblast (vSTB), the high surface area barrier epithelium of the placental villus, and the primary interface between maternal and fetal tissue. In light of increasing evidence that the placenta can adapt to changing maternal environments or, under stress, can trigger maternal disease, we consider what properties of these cells empower them to exert a controlling influence on pregnancy progression and outcome.

OBJECTIVE AND RATIONALE

How are cytotrophoblast proliferation and differentiation regulated in the human placental villus to allow for the increasing demands of the fetal and environmental challenges and stresses that may arise during pregnancy?

SEARCH METHODS

PubMed was interrogated using relevant keywords and word roots combining trophoblast, villus/villous, syncytio/syncytium, placenta, stem, transcription factor (and the individual genes), signalling, apoptosis, autophagy (and the respective genes) from 1960 to the present. Since removal of trophoblast from its tissue environment is known to fundamentally change cell growth and differentiation kinetics, research that relied exclusively on cell culture has not been the main focus of this review, though it is mentioned where appropriate. Work on non-human placenta is not systematically covered, though mention is made where relevant hypotheses have emerged.

OUTCOMES

The synthesis of data from the literature has led to a new hypothesis for vCTB dynamics. We propose that a reversible transition can occur from a reserve population in G0 to a mitotically active state. Cells from the in-cycle population can then differentiate irreversibly to intermediate cells that leave the cycle and turn on genes that confer the capacity to fuse with the overlying vSTB as well as other functions associated with syncytial barrier and transport function. We speculate that alterations in the rate of entry to the cell cycle, or return of cells in the mitotic fraction to G0, can occur in response to environmental challenge. We also review evidence on the life cycle of trophoblast from the time that fusion occurs, and point to gaps in knowledge of how large quantities of fetal DNA arrive in maternal circulation. We critique historical methodology and make a case for research to re-address questions about trophoblast lifecycle and dynamics in normal pregnancy and the common diseases of pre-eclampsia and fetal growth restriction, where altered trophoblast kinetics have long been postulated.

WIDER IMPLICATIONS

The hypothesis requires experimental testing, moving research away from currently accepted methodology towards a new standard that includes representative cell and tissue sampling, assessment of cell cycle and differentiation parameters, and robust classification of cell subpopulations in villous trophoblast, with due attention to gestational age, maternal and fetal phenotype, disease and outcome.

Increased epithelial galectin-13 expression associates with eosinophilic airway inflammation in asthma

BACKGROUND

Airway eosinophilic inflammation is a central feature in asthma which is mainly driven by type 2 response. The expression of galectin-13 was up-regulated in a parasitic infection model which is also characterized by type 2 immune response. We hypothesized that galectin-13 may be involved in airway eosinophilic inflammation in asthma.

OBJECTIVE

To unveil the role of galectin-13 in asthma airway inflammation.

METHODS

We measured galectin-13 expressions in bronchial brushings, sputum, and plasma of asthma patients (n = 54) and healthy controls (n = 15), and analysed the correlations between galectin-13 expression and airway eosinophilia. We used human bronchial epithelial cell line 16HBE to investigate the possible mechanism by which galectin-13 participates in eosinophilic inflammation.

RESULTS

The expression of galectin-13 was markedly increased in subjects with asthma compared to controls. Epithelial galectin-13 mRNA levels in asthmatic subjects were strongly correlated with eosinophilic airway inflammation (the percentage of sputum eosinophils, the number of eosinophils in bronchial submucosa and FeNO) and the expression of Th2 signature genes (CLCA1, POSTN and SERPINB2). Inhaled corticosteroid (ICS) treatment reduced plasma galectin-13 levels, and baseline plasma galectin-13 levels reflect the response to ICS treatment. In cultured 16HBE cells, knockdown of galectin-13 suppressed IL-13-stimulated MCP-1 and eotaxin-1 expression by inhibiting the activation of EGFR and ERK.

CONCLUSIONS & CLINICAL RELEVANCE

Galectin-13 is a novel marker for airway eosinophilia in asthma, and may contribute to allergic airway eosinophilic inflammation by up-regulating the expression of MCP-1 and eotaxin-1. Plasma galectin-13 levels may be useful for predicting responses to ICS treatment.

Insight into the Key Points of Preeclampsia Pathophysiology: Uterine Artery Remodeling and the Role of MicroRNAs

Preeclampsia affects about 3-8% of all pregnancies. It represents a complex and multifaceted syndrome with at least several potential pathways leading to the development of disease. The main dogma in preeclampsia is the two-stage model of disease. Stage 1 (placental stage) takes place in early pregnancy and is thought to be impaired placentation due to inadequate trophoblastic invasion of the maternal spiral arteries that leads to reduced placental perfusion and release of numerous biological factors causing endothelial damage and development of acute maternal syndrome with systemic multiorgan failure (stage 2-the onset of maternal clinical symptoms, maternal stage). Recently, in the light of the vast body of evidence, two-stage model of preeclampsia has been updated with a few novel pathways leading to clinical manifestation in the second part of pregnancy. This paper reviews current state of knowledge about pathophysiology of preeclampsia and places particular focus on the recent advances in understanding of uterine artery remodeling alterations, as well as the role of microRNAs in preeclampsia.

Galectin-14 Promotes Trophoblast Migration and Invasion by Upregulating the Expression of MMP-9 and N-Cadherin

Galectin-14 is specifically expressed in placental trophoblasts, and its expression is reduced in trophoblasts retrieved from the cervix of women destined to develop early pregnancy loss. However, the roles of galectin-14 in regulating trophoblasts and in the pathogenesis of pregnancy complication have never been investigated. In the current research, we aimed to investigate the roles of galectin-14 in the regulation of trophoblasts. Tissues of the placenta and villi were collected. Primary trophoblasts and human trophoblast cell line HTR-8/SVneo were used. Western blotting and RT-PCR were used to quantify gene expression. The siRNA-mediated galectin-14 knockdown and lentivirus-mediated overexpression were performed to manipulate the gene expression in trophoblasts. Transwell migration and invasion assays were used to evaluate cell migration and invasion capacity. Gelatin zymography was used to determine the gelatinase activity. Galectin-14 was significantly decreased in the villi of early pregnancy loss and the placenta of preeclampsia. Knockdown of galectin-14 in primary trophoblasts inhibited cell migration and invasion, downregulated the expression of matrix metalloproteinase (MMP)-9 and N-cadherin, the activity of MMP-9, and decreased the phosphorylation of Akt. Meanwhile, the overexpression of galectin-14 in HTR-8/SVneo promoted cell migration and invasion, upregulated the expression of MMP-9 and N-cadherin, the activity of MMP-9, and increased the phosphorylation of Akt. Increased Akt phosphorylation promoted cell migration and invasion and upregulated the expression and activity of MMP-9, while decreased Akt phosphorylation inhibited cell migration and invasion and downregulated the expression and activity of MMP-9. Thus, galectin-14 promotes trophoblast migration and invasion by enhancing the expression of MMP-9 and N-cadherin through Akt phosphorylation. The dysregulation of galectin-14 is involved in the pathogenesis of early pregnancy loss and preeclampsia.

Overexpression of Galectin10 Predicts a Better Prognosis in Human Ovarian Cancer

To explore the prognosis of Galectins (LGALS) expression on patients with ovarian cancer, the prognosis of LGALS members in ovarian cancer was retrieved and analyzed by using 'Kaplan-Meier plotter' database. The relation of LGALS to overall survival (OS) was evaluated according to histological subtypes, clinical stages and pathological grade. Quantitative real-time polymerase chain reaction and western blot were used to detect the mRNA and protein expression of LGALS in ovarian cancer and normal ovarian cells. Immunohistochemistry was applied to evaluate the different expression of LGALS between cancer and normal tissues. In total patients with ovarian cancer, LGALS4, LGALS8, LGALS10 and LGALS13 mRNA levels were related to a better OS, and LGALS1 to a worse OS. LGALS1 predicted a worse OS in women with serous, stages III+IV or grade II ovarian cancer. LGALS4 predicted a better OS in patients with endometrioid, stages I+II or grade III ovarian cancer. LGALS10 predicted a longer OS in females with serous, all stages, or grade III cancer. LGALS8 overexpression was related to a better OS in all stages. Notably, mRNA and protein expressions of LGALS4, LGALS10 and LGALS13 were decreased in cancer cells than those in normal cells (P<0.05). Additionally, the immunostaining score of LGALS8, LGALS10 and LGALS13 expression were lower but LGALS1 was higher in caner tissues than those in normal tissues (P<0.001). In conclusion, LGALS10 possibly is a valuable biomarker for predicting a favorable prognosis in patients with ovarian cancer, especially with serous, all stages and grade III cancer.

Examining Sex Differences in the Human Placental Transcriptome During the First Fetal Androgen Peak

Sex differences in human placenta exist from early pregnancy to term, however, it is unclear whether these differences are driven solely by sex chromosome complement or are subject to differential sex hormonal regulation. Here, we survey the human chorionic villus (CV) transcriptome for sex-linked signatures from 11 to 16 gestational weeks, corresponding to the first window of increasing testis-derived androgen production in male fetuses. Illumina HiSeq RNA sequencing was performed on Lexogen Quantseq 3' libraries derived from CV biopsies (n = 11 females, n = 12 males). Differential expression (DE) was performed to identify sex-linked transcriptional signatures, followed by chromosome mapping, pathway analysis, predicted protein interaction, and post-hoc linear regressions to identify transcripts that trend over time. We observe 322 transcripts DE between male and female CV from 11 to 16 weeks, with 22 transcripts logFC > 1. Contrary to our predictions, the difference between male and female expression of DE autosomal genes was more pronounced at the earlier gestational ages. In females, we found selective upregulation of extracellular matrix components, along with a number of X-linked genes. In males, DE transcripts centered on chromosome 19, with mitochondrial, immune, and pregnancy maintenance-related transcripts upregulated. Among the highest differentially expressed autosomal genes were CCRL2, LGALS13, and LGALS14, which are known to regulate immune cell interactions. Our results provide insight into sex-linked gene expression in late first and early second trimester developing human placenta and lay the groundwork to understand the mechanistic origins of sex differences in prenatal development.

Human galectin-16 has a pseudo ligand binding site and plays a role in regulating c-Rel-mediated lymphocyte activity

BACKGROUND

The structure of human galectin-16 (Gal-16) has yet to be solved, and its function has remained elusive.

METHODS

X-ray crystallography was used to determine the atomic structures of Gal-16 and two of its mutants. The Gal-16 oligomer state was investigated by gel filtration, its hemagglutination activity was determined along with its ability to bind lactose using ITC. The cellular distribution of EGFP-tagged Gal-16 in various cell lines was also investigated, and the interaction between Gal-16 and c-Rel was assessed by pull-down studies, microscale thermophoresis and immunofluorescence.

RESULTS

Unlike other galectins, Gal-16 lacks the ability to bind the β-galactoside lactose. Lactose binding could be regained by replacing an arginine (Arg55) with asparagine, as shown in the crystal structures of two lactose-loaded Gal-16 mutants (R55N and R55N/H57R). Gal-16 was also shown to be monomeric by gel filtration, as well as in crystal structures. Thus, this galectin could not induce erythrocyte agglutination. EGFP-tagged Gal-16 was found to be localized mostly in the nucleus of various cell types, and can interact with c-Rel, a member of NF-κB family.

CONCLUSIONS

Gal-16 exists as a monomer and its ligand binding is significantly different from that of other prototype galectins, suggesting that it has a novel function(s). The interaction between Gal-16 and c-Rel indicates that Gal-16 may regulate signal transduction pathways via the c-Rel hub in B or T cells at the maternal-fetal interface.

GENERAL SIGNIFICANCE

The present study lays the foundation for further studies into the cellular and physiological functions of Gal-16.

Proteomic identification of Placental Protein 1 (PP1), PP8, and PP22 and characterization of their placental expression in healthy pregnancies and in preeclampsia

INTRODUCTION

Placental Protein 1 (PP1), PP8, and PP22 were isolated from the placenta. Herein, we aimed to identify PP1, PP8, and PP22 proteins and their placental and trophoblastic expression patterns to reveal potential involvement in pregnancy complications.

METHODS

We analyzed PP1, PP8, and PP22 proteins with LC-MS. We compared the placental behaviors of PP1, PP8, and PP22 to the predominantly placenta-expressed PP5/TFPI-2. Placenta-specificity scores were generated from microarray data. Trophoblasts were isolated from healthy placentas and differentiated; total RNA was isolated and subjected to microarray analysis. We assigned the placentas to the following groups: preterm controls, early-onset preeclampsia, early-onset preeclampsia with HELLP syndrome, term controls, and late-onset preeclampsia. After histopathologic examination, placentas were used for tissue microarray construction, immunostaining with anti-PP1, anti-PP5, anti-PP8, or anti-PP22 antibodies, and immunoscoring.

RESULTS

PP1, PP8, and PP22 were identified as 'nicotinate-nucleotide pyrophosphorylase', 'serpin B6', and 'protein disulfide-isomerase', respectively. Genes encoding PP1, PP8, and PP22 are not predominantly placenta-expressed, in contrast with PP5. PP1, PP8, and PP22 mRNA expression levels did not increase during trophoblast differentiation, in contrast with PP5. PP1, PP8, and PP22 immunostaining were detected primarily in trophoblasts, while PP5 expression was restricted to the syncytiotrophoblast. The PP1 immunoscore was higher in late-onset preeclampsia, while the PP5 immunoscore was higher in early-onset preeclampsia.

DISCUSSION

PP1, PP8, and PP22 are expressed primarily in trophoblasts but do not have trophoblast-specific regulation or functions. The distinct dysregulation of PP1 and PP5 expression in either late-onset or early-onset preeclampsia reflects different pathophysiological pathways in these preeclampsia subsets.

New predictors of early impaired placentation preceding miscarriage before 10 weeks of gestation in IVF pregnancies: A prospective study

INTRODUCTION

In a recent study of 10,011 pregnant women, 95% of miscarriages occurred before routine ultrasound scan at 11-14 weeks. Our study aimed to identify early first trimester parameters which may predict miscarriage before 10 weeks of gestation for in vitro fertilization (IVF) pregnancies.

METHODS

A cohort of 115 healthy IVF patients with a singleton viable embryo in early first trimester were studied in a tertiary university-affiliated medical center (April 2017-June 2018). Calculations included gestational age (GA); ultrasound evaluation of crown-rump length (CRL), mean gestational sac diameter (GSD) and volume (GSV), mean yolk sac diameter (YSD) and volume (YSV); fetal heart rate (FHR), mean uterine arteries pulsatility index (UtA-PI); and maternal blood placental protein 13 (PP13) levels. Patients were divided into three groups by GA; and early miscarriage versus ongoing pregnancy after GA 10 weeks.

RESULTS

Early fetal loss occurred in 14.8% of patients; miscarriage group had higher discrepancy between calculated and measured GA (P < 0.001), lower GSD and GSV (P = 0.005 and P = 0.02, respectively), significantly different YSD and YSV, and lower GSD/YSD and GSV/YSV ratios (P = 0.001 and P = 0.003, respectively). UtA-PI/CRL ratio was higher in patients with miscarriage at GA 46-48 days and GA >48 days (P = 0.034 and P = 0.026, respectively). PP13/CRL ratio was higher in patients with miscarriage at GA >48 days (P = 0.041).

DISCUSSION

In IVF pregnancies with live embryo at first ultrasound scan, high UtA-PI/CRL and maternal blood PP13/CRL ratios may indicate impaired placentation preceded early pregnancy loss. A larger cohort is needed to further verify these predictions.

The Emerging Role of Galectins and O-GlcNAc Homeostasis in Processes of Cellular Differentiation

Galectins are a family of soluble β-galactoside-binding proteins with diverse glycan-dependent and glycan-independent functions outside and inside the cell. Human cells express twelve out of sixteen recognized mammalian galectin genes and their expression profiles are very different between cell types and tissues. In this review, we summarize the current knowledge on the changes in the expression of individual galectins at mRNA and protein levels in different types of differentiating cells and the effects of recombinant galectins on cellular differentiation. A new model of galectin regulation is proposed considering the change in O-GlcNAc homeostasis between progenitor/stem cells and mature differentiated cells. The recognition of galectins as regulatory factors controlling cell differentiation and self-renewal is essential for developmental and cancer biology to develop innovative strategies for prevention and targeted treatment of proliferative diseases, tissue regeneration, and stem-cell therapy.

Characterization and functional study of Galectin3 from Japanese flounder (Paralichthys olivaceus)

Galectins belong to the β-galactoside binding protein family and participate in both innate and acquired immunity. In this study, we described the molecular characteristics of Galectin3 gene from Japanese flounder (Paralichthys olivaceus), designed as PoGalectin3. Its open reading frame was 1128 bp, encoding a protein composed of 375 amino acids. PoGalectin3 belongs to chimeric galactose agglutinin, which contains a C-terminal carbohydrate recognition domain (CRD) (L₂₅₀-P₃₇₂), and its N-terminal is rich in proline (P) and glycine (G). Multiple sequence alignment and phylogenetic tree showed that PoGalectin3 was conservative in different aquatic animals. Tissue distribution confirmed that PoGalectin3 showed significantly highest expression in brain, moderate expression in liver, intestine and muscle. PoGalectin3 was significantly increased post infection with Edwardsiella tarda from intestine tissue of P. olivaceus. In order to investigate the binding ability of PoGalectin3 to pathogen-associated molecular patterns, the recombinant PoGalectin3 protein (rPoGalectin3) was successfully expressed and purified, and an Enzyme linked immunosorbent assay (ELISA) experiment was performed. ELISA refers to the qualitative and quantitative detection method of immune response by combining soluble antigen or antibody with solid-phase carrier. It was confirmed that rPoGalectin3 exhibited high affinity to lipopolysaccharide and peptidoglycan. The rPoGalectin3 also exhibited a concentration dependent binding capacity with Gram-positive bacteria (Bacillus pumilus, Bacillus subtilis, Bacillus cereus) and Gram-negative bacteria (Aeromonas salmonicida, E. tarda, Vibrio vulnificus). In addition, the results of microbial agglutination experiment showed that rPoGalectin3 could agglutinate Gram-positive bacteria (B. pumilus, B. subtilis) and Gram-negative bacteria (A. salmonicida, E. tarda) in the presence of Ca²⁺. In conclusion, this research laid an important foundation for the specific function analysis of PoGalectin3, which provide theoretical basis for the prevention and control of aquatic diseases.

Role of galectin-glycan circuits in reproduction: from healthy pregnancy to preterm birth (PTB)

Growing evidence suggests that galectins, an evolutionarily conserved family of glycan-binding proteins, fulfill key roles in pregnancy including blastocyst implantation, maternal-fetal immune tolerance, placental development, and maternal vascular expansion, thereby establishing a healthy environment for the growing fetus. In this review, we comprehensively present the function of galectins in shaping cellular circuits that characterize a healthy pregnancy. We describe the current understanding of galectins in term and preterm labor and discuss how the galectin-glycan circuits contribute to key immunological pathways sustaining maternal tolerance and preventing microbial infections. A deeper understanding of the glycoimmune pathways regulating early events in preterm birth could offer the broader translational potential for the treatment of this devastating syndrome.

Regulatory T Cells in Pregnancy: It Is Not All About FoxP3

In pregnancy, the semi-allogeneic fetus needs to be tolerated by the mother's immune system. Regulatory T cells (Tregs) play a prominent role in this process. Novel technologies allow for in-depth phenotyping of previously unidentified immune cell subsets, which has resulted in the appreciation of a vast heterogeneity of Treg subsets. Similar to other immunological events, there appears to be great diversity within the Treg population during pregnancy, both at the maternal-fetal interface as in the peripheral blood. Different Treg subsets have distinct phenotypes and various ways of functioning. Furthermore, the frequency of individual Treg subsets varies throughout gestation and is altered in aberrant pregnancies. This suggests that distinct Treg subsets play a role at different time points of gestation and that their role in maintaining healthy pregnancy is crucial, as reflected for instance by their reduced frequency in women with recurrent pregnancy loss. Since pregnancy is essential for the existence of mankind, multiple immune regulatory mechanisms and cell types are likely at play to assure successful pregnancy. Therefore, it is important to understand the complete microenvironment of the decidua, preferably in the context of the whole immune cell repertoire of the pregnant woman. So far, most studies have focused on a single mechanism or cell type, which often is the FoxP3 positive regulatory T cell when studying immune regulation. In this review, we instead focus on the contribution of FoxP3 negative Treg subsets to the decidual microenvironment and their possible role in pregnancy complications. Their phenotype, function, and effect in pregnancy are discussed.

Molecular profiling of an osseous metastasis in glioblastoma during checkpoint inhibition: potential mechanisms of immune escape

Peripheral metastases of glioblastoma (GBM) are very rare despite the ability of GBM cells to pass through the blood-brain barrier and be disseminated through the peripheral blood. Here, we describe a detailed genetic and immunological characterization of a GBM metastasis in the skeleton, which occurred during anti-PD-1 immune checkpoint therapy. We performed whole genome sequencing (WGS) and 850 K methylation profiling of the primary and recurrent intracranial GBM as well as one of the bone metastases. Copy number alterations (CNA) and mutational profiles were compared to known genomic alterations in the TCGA data base. In addition, immunophenotyping of the peripheral blood was performed. The patient who was primarily diagnosed with IDH-wildtype GBM. After the resection of the first recurrence, progressive intracranial re-growth was again detected, and chemotherapy was replaced by PD-1 checkpoint inhibition, which led to a complete intracranial remission. Two months later MR-imaging revealed multiple osseous lesions. Biopsy confirmed the GBM origin of the skeleton metastases. Immunophenotyping reflected the effective activation of a peripheral T-cell response, with, however, increase of regulatory T cells during disease progression. WGS sequencing demonstrated distinct genomic alterations of the GBM metastasis, with gains along chromosomes 3 and 9 and losses along chromosome 4, 10, and 11. Mutational analysis showed mutations in potentially immunologically relevant regions. Additionally, we correlated tumour-infiltrating lymphocyte and microglia presence to the occurrence of circulating tumour cells (CTCs) in a larger cohort and found a decreased infiltration of cytotoxic T cells in patients positive for CTCs. This study exemplifies that the tumour microenvironment may dictate the response to immune checkpoint therapy. In addition, our study highlights the fact that despite an effective control of intracranial GBM, certain tumour clones have the ability to evade the tumour-specific T-cell response and cause progression even outside of the CNS.

Identification of Structural Variation in Chimpanzees Using Optical Mapping and Nanopore Sequencing

Recent efforts to comprehensively characterize great ape genetic diversity using short-read sequencing and single-nucleotide variants have led to important discoveries related to selection within species, demographic history, and lineage-specific traits. Structural variants (SVs), including deletions and inversions, comprise a larger proportion of genetic differences between and within species, making them an important yet understudied source of trait divergence. Here, we used a combination of long-read and -range sequencing approaches to characterize the structural variant landscape of two additional Pan troglodytes verus individuals, one of whom carries 13% admixture from Pan troglodytes troglodytes. We performed optical mapping of both individuals followed by nanopore sequencing of one individual. Filtering for larger variants (>10 kbp) and combined with genotyping of SVs using short-read data from the Great Ape Genome Project, we identified 425 deletions and 59 inversions, of which 88 and 36, respectively, were novel. Compared with gene expression in humans, we found a significant enrichment of chimpanzee genes with differential expression in lymphoblastoid cell lines and induced pluripotent stem cells, both within deletions and near inversion breakpoints. We examined chromatin-conformation maps from human and chimpanzee using these same cell types and observed alterations in genomic interactions at SV breakpoints. Finally, we focused on 56 genes impacted by SVs in >90% of chimpanzees and absent in humans and gorillas, which may contribute to chimpanzee-specific features. Sequencing a greater set of individuals from diverse subspecies will be critical to establish the complete landscape of genetic variation in chimpanzees.

Placental Protein 13 (Galectin-13) Polarizes Neutrophils Toward an Immune Regulatory Phenotype

Termed as galectin-13, placental protein 13 (PP13) is exclusively expressed in the placenta of anthropoid primates. Research on PP13 in normal and pathologic pregnancies show alteration of PP13 concentrations in pregnancy affected by preeclampsia or gestational diabetes. Galectins are also described as potent immunomodulators, and PP13 regulates T cell function in the placenta. Therefore, this study aims to investigate the effects of PP13 on neutrophils; a cell type often ignored in pregnancy, but present in the uterus and placenta from the early stages of pregnancy. Since neutrophil function is dysregulated during pathologic pregnancies, a link between PP13 and neutrophil activity is possible. We determined that PP13 reduces the apoptosis rate in neutrophils. Also, PP13 increases the expression of PD-L1 and production of HGF, TNF-α, reactive oxygen species (ROS), and MMP-9 in these cells. This phenotype resembles one observed in permissive tumor neutrophils; able to sustain tissue and vessel growth, and inhibit T cell activation. At the same time, PP13 does not alter all neutrophil functions, i.e., extrusion of neutrophil extracellular traps, degranulation, phagocytosis, and ROS production following bacterial exposure. PP13 seems to play an essential role in regulating the activity of neutrophils in the placenta by polarizing them toward a placental-growth-permissive phenotype.

In vitro fertilization and embryo transfer alter human placental function through trophoblasts in early pregnancy

The mechanism underlying the potential risk associated with in vitro fertilization and embryo transfer (IVF‑ET) has been previously investigated but remains to be fully elucidated. As the placenta is a critical organ that sustains and protects the fetus, this is an important area of research. The aim of the present study was to determine the difference in trophoblast cell function in the first trimester between naturally conceived pregnancies and pregnancies achieved via IVF‑ET therapy. A total of 20 placental villi in first trimester samples were obtained through fetal bud aspiration from patients undergoing IVF‑ET due to oviductal factors between January 2016 and August 2018. In addition, a further 20 placental villi were obtained from those who naturally conceived and had normal pregnancies but were undergoing artificial abortion; these patients were recruited as the controls. Reverse transcription‑quantitative (RT‑q)PCR and semi‑quantitative immunohistochemical methods were used to detect the mRNA and protein expression of α‑fetoprotein (AFP), vascular endothelial growth factor (VEGF), transferrin (TF), tubulin β1 class VI (TUBB1), metallothionein 1G (MT1G), BCL2, glial cells missing transcription factor 1 (GCM1), epidermal growth factor (EGF) receptor (EGFR), PTEN and leukocyte associated immunoglobulin like receptor 2 (LAIR2) in villi from both groups. Differentially expressed genes were analyzed using Search Tool for the Retrieval of Interacting Genes, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted. The RT‑qPCR data revealed that the mRNA expression levels of AFP, VEGF and TF were significantly higher in the IVF‑ET group than in the control group (P<0.05), and those of TUBB1, MT1G, BCL2, GCM1, EGFR, PTEN and LAIR2 were significantly lower (P<0.05). These gene products were expressed in the placental villus tissues, either in the cytoplasm, or in the membrane of syncytiotrophoblast and cytotrophoblast cells. The immunohistochemistry results were in line with those observed using RT‑qPCR. KEGG pathway analysis indicated that the trophoblast cell function of the IVF‑ET group in the first trimester was different from naturally conceived pregnancies with regard to proliferation, invasion, apoptosis and vascular development. The IVF‑ET process may trigger adaptive placental responses, and these compensatory mechanisms could be a risk for certain diseases later in life.