RANKL promotes the growth of decidual stromal cells in an autocrine manner via CCL2/CCR2 interaction in human early pregnancy

Tissue expression and promoter activity analysis of the porcine TNFSF11 gene

Tumour necrosis factor (TNF) superfamily member 11 (TNFSF11), also known as RANKL, plays a crucial role in regulating several physiological and pathological activities. Additionally, it is a vital factor in bone physiology, and the sex hormone progesterone regulates the expansion of stem cells and the proliferation of mammary epithelial cells. It is essential for animal growth and reproductive physiological processes. This study aimed to evaluate the tissue-specific expression characteristics and promoter activity of the TNFSF11 gene in pigs. As a result, the study examined the presence of TNFSF11 expression in the tissues of Xiangsu pigs at 0.6 and 12 months of age. Moreover, the core promoter region of TNFSF11 was also identified by utilizing a combination of bioinformatic prediction and dual-luciferase activity tests. Finally, the effect of transcription factors on the transcriptional activity of the core promoter region was determined using site-directed mutagenesis. TNFSF11 was uniformly expressed in all tissues; however, its expression in muscles was comparatively low. The core promoter region of TNFSF11 was located in the -555 to -1 region. The prediction of the transcription start site of TNFSF11 gene-2000 ∼ + 500bp showed that there was a CpG site in 17 ∼ + 487bp. Analysis of mutations in the transcription factor binding sites revealed that mutations in the Stat5b, Myog, Trl, and EN1 binding sites had significant effects on the transcriptional activity of the TNFSF11 gene, particularly following the EN1 binding site mutation (P < 0.001). This study provides insights into both the tissue-specific expression patterns of TNFSF11 in the tissues of Xiangsu pigs and the potential regulatory effects of transcription factors on its promoter activity. These results may be helpful for future research aimed at clarifying the expression and role of the porcine TNFSF11 gene.

A Hypoxia-Decidual Macrophage Regulatory Axis in Normal Pregnancy and Spontaneous Miscarriage

The significance of hypoxia at the maternal-fetal interface is proven to be self-explanatory in the context of pregnancy. During the first trimester, low oxygen conditions play a crucial role in processes such as angiogenesis, trophoblast invasion and differentiation, and immune regulation. Recently, there has been increasing research on decidual macrophages, which contribute to the maintenance of immune tolerance, placental and fetal vascular development, and spiral artery remodeling, to investigate the effects of hypoxia on their biological behaviors. On these grounds, this review describes the dynamic changes in oxygen levels at the maternal-fetal interface throughout gestation, summarizing current knowledge on how the hypoxic environment sustains a successful pregnancy by regulating retention, differentiation and efferocytosis of decidual macrophages. Additionally, we explore the relationship between spontaneous miscarriages and an abnormal hypoxia-macrophage axis, shedding light on the underlying mechanisms. However, further studies are essential to elucidate these pathways in greater detail and to develop targeted interventions that could improve pregnancy outcomes.

Early Mid-pregnancy Blood-Based Proteins as Possible Biomarkers of Increased Infant Birth Size in Sex-Stratified Analyses

The objective of this study was to evaluate the associations of 92 maternal blood-based proteins with increased infant birth size. The study was performed at the Uppsala University Hospital, Sweden, and included 857 mother and child dyads. The mean age of the women was 30.3 years, and 53.2% were nulliparous. Blood samples were collected at mean 18 + 2 weeks' gestation, and the Olink cardiovascular II panel was used to measure 92 proteins, either known to be or suspected to be markers of cardiovascular and inflammatory disease in humans. Multiple linear regression models adjusted for maternal age, parity, pre-conception BMI, height, and smoking were performed to evaluate the association of each individual protein with infant birth size. We also performed sex-stratified analyses. Eight proteins (Matrix metalloproteinase-12 (MMP-12), Prostasin (PRSS8), Adrenomedullin (ADM), Pappalysin-1 (PAPP-A), Angiotensin-converting enzyme 2 (ACE2), Sortilin (SORT1), Lectin-like oxidized LDL receptor 1 (LOX-1), and Thrombomodulin (TM)) were associated with infant birth size after false discovery rate adjustment. In the analyses including only female infants, ten proteins (MMP-12, Growth/differentiation factor 2 (GDF-2), PRSS8, SORT1, ADM, Interleukin-1 receptor antagonist protein (IL-1ra), Leptin (LEP), ACE2, TM, and Tumor necrosis factor receptor superfamily member 11A (TNFRSF11A)) were associated with infant birth size. Two proteins (PAPP-A and PRSS8) were associated with infant birth size among male infants. Our study suggests several proteins as potential biomarkers for increased birth weight, and our findings could act as a base for future research to identify new potential markers that could be added to improve screening for large infants.

CCL2: An important cytokine in normal and pathological pregnancies: A review

C-C motif ligand 2 (CCL2), also known as monocytic chemotactic protein 1 (MCP-1), is an integral chemotactic factor which recruits macrophages for the immune response. Together with its receptors (e.g., CCR2, ACKR1, and ACKR2), they exert noticeable influences on various diseases of different systems. At the maternal-fetal interface, CCL2 is detected to be expressed in trophoblasts, decidual tissue, the myometrium, and others. Meanwhile, existing reports have determined a series of physiological regulators of CCL2, which functions in maintaining normal recruitment of immunocytes, tissue remodeling, and angiogenesis. However, abnormal levels of CCL2 have also been reported to be associated with adverse pregnancy outcomes such as spontaneous abortion, preeclampsia and preterm labor. In this review, we concentrate on CCL2 expression at the maternal-fetal interface, as well as its precise regulatory mechanisms and classic signaling pathways, to reveal the multidimensional aspects of CCL2 in pregnancy.

Regulation and Function of Chemokines at the Maternal–Fetal Interface

Successful pregnancy requires the maternal immune system to tolerate the semi-allogeneic embryo. A good trophoblast function is also essential for successful embryo implantation and subsequent placental development. Chemokines are initially described in recruiting leukocytes. There are rich chemokines and chemokine receptor system at the maternal–fetal interface. Numerous studies have reported that they not only regulate trophoblast biological behaviors but also participate in the decidual immune response. At the same time, the chemokine system builds an important communication network between fetally derived trophoblast cells and maternally derived decidual cells. However, abnormal functions of chemokines or chemokine receptors are involved in a series of pregnancy complications. As growing evidence points to the roles of chemokines in pregnancy, there is a great need to summarize the available data on this topic. This review aimed to describe the recent research progress on the regulation and function of the main chemokines in pregnancy at the maternal–fetal interface. In addition, we also discussed the potential relationship between chemokines and pregnancy complications.

Modulation of the chemokine/chemokine receptor axis as a novel approach for glioma therapy

Chemokines are a large subfamily of cytokines known for their ability to facilitate cell migration, most notably leukocytes, throughout the body. Chemokines are necessary for a functioning immune system in both health and disease and have received considerable attention for their roles in orchestrating temporal-spatial regulation of immune cell populations in cancer. Gliomas comprise a group of common central nervous system (CNS) primary tumors that are extremely challenging to treat. Immunotherapy approaches for highly malignant brain tumors offer an exciting new avenue for therapeutic intervention but so far, have seen limited successful clinical outcomes. Herein we focus on important chemokine/chemokine receptor systems in the regulation of pro- and anti-tumor mechanisms, highlighting potential therapeutic advantages of modulating these systems in malignant gliomas and other cancers.

Decidual RANKL/RANK interaction promotes the residence and polarization of TGF-β1-producing regulatory γδ T cells

ABSTACT

Decidual γδΤ (dγδΤ) cells play an essential role during successful pregnancy; however, the residence and polarization of γδΤ cells in decidua remain unclear. In this study, we observed higher levels of receptor activator for nuclear factor-κ B ligand (RANKL) on decidual stromal cells (DSCs), and its receptor RANK on dγδΤ cells in decidua from normal pregnancy compared with patients with recurrent spontaneous abortion (RSA). RANKL expressed by DSCs can induce the polarization of peripheral blood γδΤ (pγδΤ) and dγδΤ cells to Foxp3 + γδΤ cells, and upregulate the expression of transforming growth factor (TGF)-β1. This process is mediated through activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In addition, RANKL promotes the adhesion of dγδΤ cells to DSCs in vitro, which is associated with the upregulation of ICAM-1 and VCAM-1 on DSCs and integrins on dγδΤ cells. RANKL knockout leads to the decreased numbers of uterus total γδΤ cells, Foxp3+γδΤ cells and the expression of TGF-β1, and the increased pregnancy loss in mice. These results suggest that RANKL is a pivotal regulator of maternal-fetal tolerance by triggering the polarization and residence of TGF-β1-producing Foxp3+γδΤ cells in early pregnancy. The abnormal low level of RANKL/RANK results in pregnancy loss because of the dialogue disorder between DSCs and dγδΤ cells. This observation provides a scientific basis on which a potential marker can be detected to early warning of pregnancy loss.

RANKL-mediated harmonious dialogue between fetus and mother guarantees smooth gestation by inducing decidual M2 macrophage polarization

Decidual macrophages (dMφ) contribute to maternal–fetal tolerance. However, the mechanism of dMφ differentiation during pregnancy is still largely unknown. Here, we report that receptor activator for nuclear factor-κ B ligand (RANKL), secreted by human embryonic trophoblasts and maternal decidual stromal cells (DSCs), polarizes dMφ toward a M2 phenotype. This polarization is mediated through activation of Akt/signal transducer and activator of transcription 6 (STAT6) signaling, which is associated with the upregulation of histone H3 lysine-27 demethylase Jmjd3 and IRF4 in dMφ. Such differentiated dMφ can induce a Th2 bias that promotes maternal–fetal tolerance. Impaired expression of RANKL leads to dysfunction of dMφ in vivo and increased rates of fetal loss in mice. Transfer of RANK⁺Mφ reverses mouse fetal loss induced by Mφ depletion. Compared with normal pregnancy, there are abnormally low levels of RANKL/RANK in villi and decidua from miscarriage patients. These results suggest that RANKL is a pivotal regulator of maternal–fetal tolerance by licensing dMφ to ensure a successful pregnancy outcome. This observation provides a scientific basis on which a potential therapeutic strategy can be targeted to prevent pregnancy loss.

Screening for potential genes associated with bone overgrowth after mid-shaft femur fracture in a rat model

Background

We investigated the underlying molecular mechanisms of bone overgrowth after femoral fracture by using high-throughput bioinformatics approaches.

Methods

The gene expression profile of GSE3298 (accession number) was obtained from the Gene Expression Omnibus database. Sixteen femoral growth plate samples, including nine samples without fracture and seven fracture samples for seven time points, were used for analysis. The Limma package was applied to identify differentially expressed genes (DEGs) between fractured and intact samples. The DAVID online tool was used for Gene ontology functional and pathway enrichment analysis. A protein-protein interaction (PPI) network established by String software was used to identify interactions between significant DEGs, and network modules were detected using plug-in MCODE. Additionally, a transcription regulatory network was constructed based on the ENCODE Project and PPI network.

Results

A total of 680 DEGs were screened in fractured femoral growth plate samples compared with controls, including 238 up- and 442 down-regulated genes. These DEGs were significantly involved in the calcium signaling pathway and cancer pathway. A PPI network was constructed with 167 nodes and 233 edges, and module analysis demonstrated that CCL2, CSF2, NOS2, and DLC1 may stimulate bone overgrowth after femoral fracture via anti-apoptosis-related functions. A transcription regulatory network was constructed with 387 interacting pairs, and overlapping nodes were significantly enriched in intracellular signaling cascade and regulation of cell proliferation, among others.

Conclusions

Bone overgrowth was associated with changes in the expression of identified DEGs such as CCL2, NOS2, CSF2, and DLC1 in the femoral head. They may be important in regulating bone overgrowth via the anti-apoptosis of osteoblasts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13018-017-0510-6) contains supplementary material, which is available to authorized users.

RANKL/RANK interaction promotes the growth of cervical cancer cells by strengthening the dialogue between cervical cancer cells and regulation of IL-8 secretion

Receptor activator for nuclear factor κB ligand (RANKL) is a member of the tumor necrosis factor (TNF) family. The interaction between RANKL and its receptor RANK plays an important role in the development and function of diverse tissues. However, the expression and role of RANKL in cervical cancer are still unknown. In the present study, we found that RANKL and RANK were highly co-expressed in cervical cancer. HeLa and SiHa cells secreted soluble RANKL (sRANKL), expressed member RANKL (mRANKL) and RANK. Recombinant human RANKL protein had no effect on the viability of HeLa and SiHa cells. Yet, blocking RANKL with an anti-human RANKL neutralizing antibody (α-RANKL) or recombinant human osteoprotegrin (OPG) protein resulted in the downregulation of Ki-67 and B-cell lymphoma 2 (Bcl-2) expression and an increase in Fas and Fas ligand (FasL) expression, as well as a high level of viability and a low level of apoptosis in the HeLa and SiHa cells. In addition, α-RANKL led to a decrease in IL-8 secretion. Recombinant human IL-8 protein reversed the effect of α-RANKL on the expression of proliferation- and apoptosis‑related molecules, and proliferation and apoptosis in the HeLa and SiHa cells. The present study suggests that a high level of mRANKL/RANK expression in cervical cancer lesions plays an important role in the rapid growth of cervical cancer cells possibly through strengthening the dialogue between cervical cancer cells and regulation of IL-8 secretion, which may be a possible target for cervical cancer therapy.

Interplay between low plasma RANKL and VDR-FokI polymorphism in lumbar disc herniation independently from age, body mass, and environmental factors: a case-control study in the Italian population

PURPOSE

Aim of this study was to investigate RANKL and osteoprotegerin plasma concentrations in patients affected by disc herniation, the most common epiphenomenon of disc degenerative diseases, and in a matched cohort of healthy subjects and whether the expression of these markers was associated to a polymorphism of the vitamin D receptor gene.

METHODS

For this case-control study, 110 consecutive cases affected by lumbar disc herniation (confirmed by MRI) and 110 healthy age- and sex-matched controls were enrolled. Subjects affected by any other pathology were excluded. RANKL and osteoprotegerin were measured in plasma by immunoassays. The difference in these markers between cases and controls was assessed by t test. The correlation between osteoimmunological markers concentrations, anthropometrical variables, and the expression of the pathology was statistically assessed (Pearson's test) along with the association (Fisher's exact test) with the vitamin D receptor gene genotype, determined elsewhere.

RESULTS

Despite comparable osteoprotegerin concentrations, cases, altogether or grouped for gender, express lower RANKL and, consequently, RANKL-to-osteoprotegerin ratio. While in cases RANKL and osteoprotegerin concentrations were independent from age and BMI, in controls they increased with age. Disc herniation was strongly associated with RANKL and the presence of the F allele of the VDR gene.

CONCLUSIONS

Whether vertebral bone changes precede or follow cartilage deterioration in intervertebral disc degeneration is not known. Our results suggest a reduced bone turnover rate, associated to a specific genetic background, in patients affected by lumbar disc herniation which could be one of the favoring factors for disc degeneration.

MSC and innate immune cell interactions: A lesson from human decidua

Both experimental and clinical studies revealed that stromal cells (SC) are present in decidua (DSC) and placenta (PSC) at the early and late phase of pregnancy, respectively, and they may contribute to the induction of an anti-inflammatory/tolerogenic microenvironment crucial for the establishment/maintenance of successful pregnancy. These cells share common features with mesenchymal SC. In the present contribution, we provide an overall view on DSC features and on their ability to recruit NK cells and to regulate both differentiation and function not only of NK cells but also of CD14(+) myeloid cells. NK cells represent the large majority of leukocytes populating decidual tissues during the first trimester of pregnancy. Their cross-talk with DSC is thought to play a key role in the establishment of feto-maternal tolerance. We also discuss recent data suggesting that DSC may contribute to tissue remodeling, placentation, and recruitment of leukocytes also through their interaction with innate lymphoid cells (ILC) such as ILC3, that have recently been shown to be present in decidual tissue.

Role of CCR2 in inflammatory conditions of the central nervous system

CC chemokine receptor 2 (CCR2) plays important roles in extravasation and transmigration of monocytes under inflammatory conditions. CCR2 and its ligands have been extensively studied in a range of inflammatory diseases in the central nervous system (CNS), including multiple sclerosis, Alzheimer's disease and ischemic stroke. This brief review summarizes our current understanding of the physiologic and pathologic roles of CCR2, focusing on its involvement in CNS inflammatory diseases. There appears to be a rationale for exploring therapies involving CCR2 inhibition in multiple sclerosis and ischemic stroke, but there is also evidence for immunomodulatory and protective effects of CCR2 activity during CNS inflammation. The critical balance between protective and detrimental roles of CCR2-dependent recruitment of leukocytes must therefore be carefully examined to guide safe and effective development of any therapies involving CCR2 modulation.