Role of NLRP7 in Normal and Malignant Trophoblast Cells

NLRP7 maintains the genomic stability during early human embryogenesis via mediating alternative splicing

Genomic instability is the main cause of abnormal embryo development and abortion. NLRP7 dysfunctions affect embryonic development and lead to Hydatidiform Moles, but the underlying mechanisms remain largely elusive. Here, we show that NLRP7 knockout affects the genetic stability, resulting in increased DNA damage in both human embryonic stem cells and blastoids, making embryonic cells in blastoids more susceptible to apoptosis. Mechanistically, NLRP7 can interact with factors related to alternative splicing and DNA damage response, including DDX39B, PRPF8, THRAP3 and PARP1. Moreover, NLRP7 dysfunction leads to abnormal alternative splicing of genes involved in homologous recombination in human embryonic stem cells, Such as Brca1 and Rad51. These results indicate that NLRP7-mediated Alternative splicing is potentially required for the maintenance of genome integrity during early human embryogenesis. Together, this study uncovers that NLRP7 plays an essential role in the maintenance of genetic stability during early human embryonic development by regulating alternative splicing of homologous recombination-related genes.

Trophoblastic disease and choriocarcinoma

Gestational trophoblastic disease (GTD) is a group of diseases associated with pregnancies that demonstrate abnormal development of trophoblastic cells. GTD includes hydatidiform moles (HM) that may continue to further develop into gestational trophoblastic neoplasms (GTN), such as choriocarcinoma (CC). Gestational CC is a malignant mass development that may arise from HM, from other (normal) pregnancies or from other gestational events (such as ectopic pregnancies). The aim of this review is to outline current understating of the genetics and epigenetics of GTD and gestational CC and the link between the two diseases.

HLA-C expression in extravillous trophoblasts is determined by an ELF3-NLRP2/NLRP7 regulatory axis

The distinct human leukocyte antigen (HLA) class I expression pattern of human extravillous trophoblasts (EVT) endows them with unique tolerogenic properties that enable successful pregnancy. Nevertheless, how this process is elaborately regulated remains elusive. Previously, E74 like ETS transcription factor 3 (ELF3) was identified to govern high-level HLA-C expression in EVT. In the present study, ELF3 is found to bind to the enhancer region of two adjacent NOD-like receptor (NLR) genes, NLR family pyrin domain-containing 2 and 7 (NLRP2, NLRP7). Notably, our analysis of ELF3-deficient JEG-3 cells, a human choriocarcinoma cell line widely used to study EVT biology, suggests that ELF3 transactivates NLRP7 while suppressing the expression of NLRP2. Moreover, we find that NLRP2 and NLRP7 have opposing effects on HLA-C expression, thus implicating them in immune evasion at the maternal-fetal interface. We confirmed that NLRP2 suppresses HLA-C levels and described a unique role for NLRP7 in promoting HLA-C expression in JEG-3. These results suggest that these two NLR genes, which arose via gene duplication in primates, are fine-tuned by ELF3 yet have acquired divergent functions to enable proper expression levels of HLA-C in EVT, presumably through modulating the degradation kinetics of IkBα. Targeting the ELF3-NLRP2/NLRP7-HLA-C axis may hold therapeutic potential for managing pregnancy-related disorders, such as recurrent hydatidiform moles and fetal growth restriction, and thus improve placental development and pregnancy outcomes.

Effects of early pregnancy on NOD-like receptor expression in the ovine endometrium

Introduction

Nucleotide-binding domain (NOD)-like receptors (NLRs) are expressed in the endometrium, and involved in modulating the female innate immune responses. There are conceptus-endometrial interactions during pregnancy, which ensure immune homeostasis of the maternal-fetal interface. The purpose of this study was to explore the effects of early pregnancy on NLR expression in the ovine endometrium.

Methods

Endometrial tissues were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group), and RT-qPCR, western blot and immunohistochemistry analysis were used to analyze the expression of NLRs, including NOD1, NOD2, major histocompatibility complex class II transactivator (CIITA), neuronal apoptosis inhibitor protein (NAIP), NLR family, pyrin domain-containing 1 (NLRP1), NLRP3 and NLRP7.

Results

Expression levels of NOD1, NOD2, NAIP, CIITA, NLRP1 and NLRP3 declined, but expression level of NLRP7 increased in the endometria during early pregnancy compared with nonpregnant ewes. In addition, NOD2 and CIITA proteins were located in the endometrium in a protein type-, cell type- and pregnancy status-specific manner.

Discussion

Early pregnancy modulated expression of NLR family in the ovine endometrium, which may be essential for conceptus-endometrial interactions and maternal-fetal interface immune homeostasis.

Crosstalk between inflammasomes, inflammation, and Nrf2: Implications for gestational diabetes mellitus pathogenesis and therapeutics

The role of inflammasomes in gestational diabetes mellitus (GDM) has emerged as a critical area of research in recent years. Inflammasomes, key components of the innate immune system, are now recognized for their involvement in the pathogenesis of GDM. Activation of inflammasomes in response to various triggers during pregnancy can produce pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-18 (IL-18), contributing to systemic inflammation and insulin resistance. This dysregulation not only impacts maternal health but also poses significant risks to fetal development and long-term health outcomes. Understanding the intricate interplay between inflammasomes and GDM holds promise for developing novel therapeutic strategies and interventions to mitigate the adverse effects of this condition on both mothers and their offspring. Researchers have elucidated that targeting inflammasomes using anti-inflammatory drugs and compounds can effectively reduce inflammation in GDM. Furthermore, the addition of nuclear factor erythroid 2-related factor 2 (Nrf2) to this complex mechanism opens novel avenues for therapeutics. The antioxidant properties of Nrf2 may potentially suppress inflammasome activation in GDM. This comprehensive review investigates the intricate relationship between inflammasomes and GDM, emphasizing the pivotal role of inflammation in its pathogenesis. It also sheds light on potential therapeutic strategies targeting inflammasome activation and explores the role of Nrf2 in mitigating inflammation in GDM.

Placentas from Women with Late-Onset Preeclampsia Exhibit Increased Expression of the NLRP3 Inflammasome Machinery

Pre-eclampsia is a harmful and potentially lethal medical condition during pregnancy clinically diagnosed by hypertension and commonly accompanied by proteinuria and multiorgan affections. According to the time of diagnosis, it is differentiated between early-onset (EO-PE) and late-onset preeclampsia (LO-PE). Despite being less dangerous and presenting distinct pathophysiological signatures, LO-PE has a greater prevalence than EO-PE, both having significant consequences on the placenta. Previous works have evidenced that exacerbated inflammation in this organ might play a potential pathogenic role in the development of pre-eclampsia, and there is some preliminary evidence that the hyperactivation of inflammasomes can be related to the altered immunoinflammatory responses observed in the placentas of these patients. However, the precise role of inflammasomes in the placentas of women with LO-PE remains to be fully understood. In this work, we have studied the gene and protein expression of the main components related to the canonical and non-canonical pathways of the inflammasome NLRP3 (NLRP3, ASC, caspase 1, caspase 5, caspase 8, interleukin 1β, and interleukin 18) in the placental tissue of women with LO-PE. Our results show a marked increase in all these components in the placentas of women who have undergone LO-PE, suggesting that NLRP3 inflammasome plays a potentially pathophysiological role in the development of this entity. Future works should aim to evaluate possible translational approaches to this dysregulation in these patients.

Management of trophoblastic tumors : review of evidence, current practice, and future directions

INTRODUCTION

Gestational trophoblastic neoplasia (GTN) is a group of rare tumors characterized by abnormal trophoblastic proliferation following pregnancy including invasive moles, choriocarcinomas, and intermediate trophoblastic tumors (ITT). Although the treatment and follow-up of GTN has been heterogeneous, globally the emergence of expert networks has helped to harmonize its management.

AREAS COVERED

We provide an overview of the current knowledge, diagnosis, and management strategies in GTN and discuss innovative therapeutic options under investigation. While chemotherapy has been the historical backbone of GTN treatment, promising drugs such as immune checkpoint inhibitors targeting the PD-1/PD-L1 pathway and anti-angiogenic tyrosine kinase inhibitors are currently being investigated remodeling the therapeutical landscape of trophoblastic tumors.

EXPERT OPINION

Chemotherapy regimens for GTN have potential long-term effects on fertility and quality of life, making innovative and less toxic therapeutic approaches necessary. Immune checkpoint inhibitors have shown promise in reversing immune tolerance in GTN and have been evaluated in several trials. However, immunotherapy is associated with rare but life-threatening adverse events and evidence of immune-related infertility in mice, highlighting the need for further research and careful consideration of its use. Innovative biomarkers could help personalize GTN treatments and reduce chemotherapy burden in some patients.

Changes in expression levels of Nod-like receptors in the spleen of ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) have critical effects on interfaces of the immune and reproductive systems, and the spleen plays a key role in both innate and adaptive immune functions. It is hypothesized that NLR family participates in maternal splenic immune regulation during early pregnancy in sheep. In this study, maternal spleens were collected on day 16 of the estrous cycle, and days 13, 16 and 25 of gestation (n = 6 for each group) in ewes. Expression of NLR family, including NOD1, NOD2, class II transactivator (CIITA), NLR family apoptosis inhibitory protein (NAIP), nucleotide-binding oligomerization domain, Leucine rich repeat and Pyrin domain containing 1 (NLRP1), NLRP3 and NLRP7, was analyzed using quantitative real-time PCR, Western blot and immunohistochemistry analysis. The results revealed that expression levels of NOD1, NOD2, CIITA and NLRP3 were downregulated at days 13 and 16 of pregnancy, but expression of NLRP3 was increased at day 25 of pregnancy. In addition, expression values of NAIP and NLRP7 mRNA and proteins were improved at days 16 and 25 of pregnancy, and NLRP1 was peaked at days 13 and 16 of pregnancy in the maternal spleen. Furthermore, NOD2 and NLRP7 proteins were limited to the capsule, trabeculae and splenic cords. In summary, early pregnancy changes expression of NLR family in the maternal spleen, which may be related with the maternal splenic immunomodulation during early pregnancy in sheep.

NLRP7 participates in the human subcortical maternal complex and its variants cause female infertility characterized by early embryo arrest

Successful human reproduction requires normal oocyte maturation, fertilization, and early embryo development. Early embryo arrest is a common phenomenon leading to female infertility, but the genetic basis is largely unknown. NLR family pyrin domain-containing 7 (NLRP7) is a member of the NLRP subfamily. Previous studies have shown that variants of NLRP7 are one of the crucial causes of female recurrent hydatidiform mole, but whether NLRP7 variants can directly affect early embryo development is unclear. We performed whole-exome sequencing in patients who experienced early embryo arrest, and five heterozygous variants (c.251G > A, c.1258G > A, c.1441G > A, c. 2227G > A, c.2323C > T) of NLRP7 were identified in affected individuals. Plasmids of NLRP7 and subcortical maternal complex components were overexpressed in 293 T cells, and Co-IP experiments showed that NLRP7 interacted with NLRP5, TLE6, PADI6, NLRP2, KHDC3L, OOEP, and ZBED3. Injecting complementary RNAs in mouse oocytes and early embryos showed that NLRP7 variants influenced the oocyte quality and some of the variants significantly affected early embryo development. These findings contribute to our understanding of the role of NLRP7 in human early embryo development and provide a new genetic marker for clinical early embryo arrest patients. KEY MESSAGES: Five heterozygous variants of NLRP7 (c.1441G > A; 2227G > A; c.251G > A; c.1258G > A; c.2323C > T) were identified in five infertile patients who experienced early embryo arrest. NLRP7 is a component of human subcortical maternal complex. NLRP7 variants lead to poor quality of oocytes and early embryo development arrest. This study provides a new genetic marker for clinical early embryo arrest patients.

NLRP7 Enhances Choriocarcinoma Cell Survival and Camouflage in an Inflammasome Independent Pathway

BACKGROUND

Gestational choriocarcinoma (GC) is a highly malignant trophoblastic tumor that often develops from a complete hydatidiform mole (HM). NLRP7 is the major gene responsible for recurrent HM and is involved in the innate immune response, inflammation and apoptosis. NLRP7 can function in an inflammasome-dependent or -independent pathway. Recently, we have demonstrated that NLRP7 is highly expressed in GC tumor cells and contributes to their tumorigenesis. However, the underlying mechanisms are still unknown. Here, we investigated the mechanism by which NLRP7 controls these processes in malignant (JEG-3) and non-tumor (HTR8/SVneo) trophoblastic cells. Cell survival, dedifferentiation, camouflage, and aggressiveness were compared between normal JEG-3 cells or knockdown for NLRP7, JEG-3 Sh NLRP7. In addition, HTR8/SVneo cells overexpressing NLRP7 were used to determine the impact of NLRP7 overexpression on non-tumor cells. NLRP7 involvement in tumor cell growth and tolerance was further characterized in vivo using the metastatic mouse model of GC.

RESULTS

We demonstrate that NLRP7 (i) functions in an inflammasome-dependent and -independent manners in HTR8/SVneo and JEG-3 cells, respectively; (ii) differentially regulates the activity of NF-κB in tumor and non-tumor cells; (iii) increases malignant cell survival, dedifferentiation, and camouflage; and (iv) facilitates tumor cells colonization of the lungs in the preclinical model of GC.

CONCLUSIONS

This study demonstrates for the first time the mechanism by which NLRP7, independently of its inflammasome machinery, contributes to GC growth and tumorigenesis. The clinical relevance of NLRP7 in this rare cancer highlights its potential therapeutic promise as a molecular target to treat resistant GC patients.

Immune checkpoint inhibitor using in cases with gestational trophoblastic diseases

Gestational trophoblastic neoplasias (GTNs) are chemosensitive disorders with very high cure rates. However, individuals with chemoresistant diseases pass away as a result of their illness, necessitating the use of innovative medications. Immune checkpoint inhibitors (ICIs) are a critical component of the strategy for the management of drug-resistant GTD due to the high rate of PD-1 expression and the paternal genetic inheritance in GTNs. Immunotherapy is mentioned as a potential therapeutic approach for chemotherapy-resistant GTD in the most recent worldwide recommendations. However, multicenter worldwide collaborative studies are required to give additional evidence to detect and identify prognostic markers due to the rarity of GTDs and the dearth of data in the literature.

Modulation of Nod-like Receptor Expression in the Thymus during Early Pregnancy in Ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) are involved in modulating the innate immune responses of the trophoblast and the placenta in normal pregnancy. The thymus participates in regulation of innate and adaptive immune responses. However, it is unclear whether expression of NLR is modulated in the maternal thymus during early pregnancy. In this study, thymuses were sampled at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation (n = 6 for each group) from ewes after slaughter. Different stages were chosen because the maternal thymus was under the different effects of interferon-tau and/or progesterone or not. RT-qPCR, Western blot and immunohistochemistry analysis were used to analyze the expression of the NLR family, including NOD1; NOD2; major histocompatibility complex class II transactivator (CIITA); NLR family apoptosis inhibitory protein (NAIP); nucleotide-binding oligomerization domain and Leucine-rich repeat and Pyrin domain containing protein 1 (NLRP1), NLRP3 and NLRP7. The results showed that expression level of NOD1 was changed with the pregnancy stages, and expression levels of NOD2, CIITA, NAIP, NLRP1, NLRP3 and NLRP7 mRNA and proteins were peaked at day 13 of pregnancy. The levels of NOD2 and CIITA were increased during early pregnancy. The stainings for NOD2 and NLRP7 proteins were located in epithelial reticular cells, capillaries and thymic corpuscles. In summary, pregnancy stages changed expression of NLR family in the maternal thymus, which may be related to the modulation of maternal thymic immune responses, and beneficial for normal pregnancy in sheep.

Prognostic prediction of systemic immune-inflammation status for patients with colorectal cancer: a novel pyroptosis-related model

Pyroptosis and related gasdermin family proteins play an important role in the tumorigenesis of colorectal cancer (CRC). However, the prognostic roles of pyroptosis-related genes (PRGs) and their relation to infiltrates of immune cells in the pathogenesis of CRC remain unclear. Using this study, we set up a prognostic gene pattern on the basis of 13 PRGs (AIM2, CASP1, CASP5, CASP6, CASP8, CASP9, ELANE, GPX4, GSDMD, NLRP7, NOD2, PJVK, and PRKACA) for CRC patients. A comprehensive bioinformatics analysis based on these genes was then performed. With the good AUC prediction value of the ROC curves, the group with high hazard first had a poorer survival prognosis than the group with low hazard. Second, we found that PRGs were significantly related to inflammation-associated genes and immune-associated genes in CRC. Then, we identified a correlation of PRGs with immune infiltrations in CRC. For instance, the abundances of resting NK cells resting and neutrophils were higher in the low hazard group than in the high hazard group. Overall, this work indicated that PRGs contributed to generate heterogeneity of the tumor microenvironment (TME) in CRC. This prognostic PRG model may provide a starting point for the early diagnosis and medication use of CRC.

Case Report: First-Line Immune Checkpoint Inhibitor Plus Chemotherapy for Oral Metastasis in a Patient with Ultra High-Risk Gestational Choriocarcinoma

Choriocarcinoma (CC) tends to metastasize early into various organs and may exhibit peculiar clinical behaviors specific to metastases. Although chemotherapy has revolutionized the survival of most patients, the mortality rate remains high in cases at ultra high-risk, which may be associated with multiple organs involvement and intolerable toxicity resulting from combination chemotherapy. Here, we illustrate a 46-year-old woman patient with oral and lung lesions whose clinical and morphological heterogeneity misled the preliminary diagnosis. According to the initial pathological report of oral squamous cell carcinomas with lung metastasis and a combined positive score = 100, she received first-line immunotherapy plus two-drug chemotherapy, which obtained a surprisingly favourable outcome. Then, CC was identified by a high level of beta human chorionic gonadotropin (β-HCG) in serum and biopsies. DNA polymorphic analysis revealed its gestational origin, and a more aggressive standard regimen was subsequently implemented. However, the patient suffered repeated vomiting and myelosuppression, and the duration of treatment was significantly prolonged. Ultimately, she succumbed to death. The clinical course of this report helps to improve the understanding of this disease. We consider immune checkpoint inhibitors as potential first-line alternatives for ultra-high-risk CC patients, which provide a therapeutic reference for clinicians.

The Placental NLRP3 Inflammasome and Its Downstream Targets, Caspase-1 and Interleukin-6, Are Increased in Human Fetal Growth Restriction: Implications for Aberrant Inflammation-Induced Trophoblast Dysfunction

Fetal growth restriction (FGR) is commonly associated with placental insufficiency and inflammation. Nonetheless, the role played by inflammasomes in the pathogenesis of FGR is poorly understood. We hypothesised that placental inflammasomes are differentially expressed and contribute to the aberrant trophoblast function. Inflammasome gene expression profiles were characterised by real-time PCR on human placental tissues collected from third trimester FGR and gestation-matched control pregnancies (n = 25/group). The functional significance of a candidate inflammasome was then investigated using lipopolysaccharide (LPS)-induced models of inflammation in human trophoblast organoids, BeWo cells in vitro, and a murine model of FGR in vivo. Placental mRNA expression of NLRP3, caspases 1, 3, and 8, and interleukin 6 increased (>2-fold), while that of the anti-inflammatory cytokine, IL-10, decreased (<2-fold) in FGR compared with control pregnancies. LPS treatment increased NLRP3 and caspase-1 expression (>2-fold) in trophoblast organoids and BeWo cell cultures in vitro, and in the spongiotrophoblast and labyrinth in the murine model of FGR. However, the LPS-induced rise in NLRP3 was attenuated by its siRNA-induced down-regulation in BeWo cell cultures, which correlated with reduced activity of the apoptotic markers, caspase-3 and 8, compared to the control siRNA-treated cells. Our findings support the role of the NLRP3 inflammasome in the inflammation-induced aberrant trophoblast function, which may contribute to FGR.