MNSFβ Regulates TNFα Production by Interacting with RC3H1 in Human Macrophages, and Dysfunction of MNSFβ in Decidual Macrophages Is Associated With Recurrent Pregnancy Loss

Compromised adenosine-A2AR axis contributes to recurrent spontaneous abortion by promoting proinflammatory macrophage polarization

This study investigates the association between recurrent spontaneous abortion (RSA) and macrophage polarization, exploring adenosine (Ado) as a potential biomarker and therapeutic target. By analyzing decidual tissues from RSA patients and normal pregnancies, we found reduced CD39 expression and lower adenosine levels in RSA, accompanied by increased M1 macrophage polarization and decreased M2 macrophage expression. In vitro experiments demonstrated that adenosine inhibited M1 polarization while promoting M2 polarization, an effect reversed by adenosine deaminase (ADA). Single-cell RNA sequencing revealed decreased adenosine receptor A2aR expression in M1 macrophages of RSA patients, while glycolysis-related enzyme hexokinase 2 (HK2) was overexpressed. These findings suggest that adenosine plays a key role in macrophage polarization and immune homeostasis at the maternal-fetal interface, with glycolysis potentially contributing to this process, highlighting its potential as a target for RSA diagnosis and treatment.

MNSFβ promotes LPS-induced TNFα expression by increasing the localization of RC3H1 to stress granules, and the interfering peptide HEPN2 reduces TNFα production by disrupting the MNSFβ-RC3H1 interaction in macrophages

Abnormally elevated tumor necrosis factor-α (TNFα) levels at the maternal-fetal interface can lead to adverse pregnancy outcomes, including recurrent miscarriage (RM), but the mechanism underlying upregulated TNFα expression is not fully understood. We previously reported that the interaction between monoclonal nonspecific suppressor factor-β (MNSFβ) and RC3H1 upregulates TNFα expression, but the precise mechanisms are unknown. In this study, we found that MNSFβ stimulated the LPS-induced TNFα expression by inactivating the promoting effect of RC3H1 on TNFα mRNA degradation rather than directly inhibiting the expression of RC3H1 in THP1-Mϕs. Mechanistically, the 81-326 aa region of the RC3H1 protein binds to the 101-133 aa region of the MNSFβ protein, and MNSFβ facilitated stress granules (SGs) formation and the translocation of RC3H1 to SGs by interacting with RC3H1 and fragile X mental retardation 1 (FMR1) in response to LPS-induced stress. The SGs-localization of RC3H1 reduced its inhibitory effect on TNFα expression in LPS-treated THP1-Mϕs. The designed HEPN2 peptide effectively reduced the LPS-induced expression of TNFα in THP1-Mϕs by interfering with the MNSFβ-RC3H1 interaction. Treatment with the HEPN2 peptide significantly improved adverse pregnancy outcomes, including early pregnancy loss (EPL) and lower fetal weight (LFW), which are induced by LPS in mice. These data indicated that MNSFβ promoted TNFα expression at least partially by increasing the localization of RC3H1 to SGs under inflammatory stimulation and that the HEPN2 peptide improved the adverse pregnancy outcomes induced by LPS in mice, suggesting that MNSFβ is a potential pharmacological target for adverse pregnancy outcomes caused by abnormally increased inflammation at early pregnancy.

Investigating the regulatory mechanism of glucose metabolism by ubiquitin-like protein MNSFβ

BACKGROUND

Monoclonal nonspecific suppressor factor β (MNSFβ), a ubiquitously expressed member of the ubiquitin-like protein family, is associated with diverse cell regulatory functions. It has been implicated in glycolysis regulation and cell proliferation enhancement in the macrophage-like cell line Raw264.7. This study aims to show that HIF-1α regulates MNSFβ-mediated metabolic reprogramming.

METHODS AND RESULTS

In Raw264.7 cells, MNSFβ siRNA increased the oxygen consumption rate and reactive oxygen species (ROS) production but decreased ATP levels. Cells with MNSFβ knockdown showed a markedly increased ATP reduction rate upon the addition of oligomycin, a mitochondrial ATP synthase inhibitor. In addition, MNSFβ siRNA decreased the expression levels of mRNA and protein of HIF-1α-a regulator of glucose metabolism. Evaluation of the effect of MNSFβ on glucose metabolism in murine peritoneal macrophages revealed no changes in lactate production, glucose consumption, or ROS production.

CONCLUSION

MNSFβ affects both glycolysis and mitochondrial metabolism, suggesting HIF-1α involvement in the MNSFβ-regulated glucose metabolism in Raw264.7 cells.

Immunologic insights in recurrent spontaneous abortion: Molecular mechanisms and therapeutic interventions

Recurrent spontaneous abortion refers to the occurrence of two or more spontaneous abortions before or during the early stages of pregnancy. The immune system plays a crucial role in the maintenance of pregnancy and embryo implantation. Various immune cells, cytokines, and immune regulatory pathways are involved in the complex immune balance required for a stable pregnancy. Studies suggest that immune abnormalities may be associated with some recurrent spontaneous abortion cases, particularly those involving the dysregulation of immune cell function, autoimmune responses, and placental immunity. In terms of treatment, interventions targeting immune mechanisms are crucial. Various therapeutic approaches, including immunomodulatory drugs, immunoadsorption therapies, and immunocellular therapies, are continually being researched and developed. These approaches aim to restore the immune balance, enhance the success rate of pregnancies, and provide more effective treatment options for patients with recurrent spontaneous abortion.

Increased miR-3074-5p expression promotes M1 polarization and pyroptosis of macrophages via ERα/NLRP3 pathway and induces adverse pregnancy outcomes in mice

Decidual macrophages (dMϕs) play critical roles in regulation of immune-microhomeostasis at maternal-fetal interface during pregnancy, but the underlying molecular mechanisms are still unclear. In this study, it was found that litter size and fetal weight were significantly reduced, whereas the rate of embryo resorption was increased in miR-3074-5p knock-in (3074-KI) pregnant mice, compared to that of wild-type (WT) pregnant mice. Plasma levels of pro-inflammatory cytokines in 3074-KI pregnant mice were also significantly elevated compared to WT pregnant mice at GD7.5. The quantity of M1-Mϕs in uterine tissues of 3074-KI pregnant mice was significantly increased compared to WT pregnant mice at GD13.5. Estrogen receptor-α (ERα) was validated to be a target of miR-3074-5p. Either miR-3074-5p overexpression or ERα knockdown promoted transcriptional activity of NF-κB/p65, induced M1-polarization and pyroptosis of THP1-derived Mϕs, accompanied with increased intracellular levels of cleaved Caspase-1, cleaved IL-1β, NLRP3, cleaved GSDMD and ASC aggregation. Furthermore, ERα could not only bind to NLRP3 or ASC directly, but also inhibit the interaction between NLRP3 and ASC. The endometrial miR-3074-5p expression level at the middle secretory stage of repeated implantation failure (RIF) patients was significantly decreased compared to that of control fertile women. These data indicated that miR-3074-5p could promote M1 polarization and pyroptosis of Mϕs via activation of NLRP3 inflammasome by targeting ERα, and the dysregulation of miR-3074-5p expression in dMϕs might damage the embryo implantation and placentation by interfering with inflammatory microenvironment at the maternal-fetal interface during early pregnancy.

Estrogen-sensitive activation of SGK1 induces M2 macrophages with anti-inflammatory properties and a Th2 response at the maternal-fetal interface

BACKGROUND

Decidual macrophages participate in immune regulation at the maternal-fetal interface. Abnormal M1/M2 polarization of decidual macrophages might predispose immune maladaptation in recurrent pregnancy loss (RPL). However, the mechanism of decidual macrophage polarization is unclear. We explored the role of Estradiol (E₂)-sensitive serum-glucocorticoid regulated kinase (SGK) 1 in promoting macrophage polarization and suppressing inflammation at the maternal-fetal interface.

METHODS

We assessed serum levels of E₂ and progesterone during first trimester of pregnancy in women with or without threatened miscarriages (ended in live birth, n = 448; or early miscarriages, n = 68). For detection of SGK1 in decidual macrophages, we performed immunofluorescence labeling and western blot analysis applying decidual samples from RPL (n = 93) and early normal pregnancy (n = 66). Human monocytic THP-1 cells were differentiated into macrophages and treated with Toll-like receptor (TLR) 4 ligand lipopolysaccharide (LPS), E₂, inhibitors or siRNA for in vitro analysis. Flow cytometry analysis were conducted to detect macrophages polarization. We also applied ovariectomized (OVX) mice with hormones exploring the mechanisms underlying the regulation of SGK1 activation by E₂ in the decidual macrophages in vivo.

RESULTS

SGK1 expression down regulation in the decidual macrophages of RPL was consistent with the lower concentration and slower increment of serum E₂ from 4 to 12 weeks of gestation seen in these compromised pregnancies. LPS reduced SGK1 activities, but induced the pro-inflammatory M1 phenotype of THP-1 monocyte-derived macrophages and T helper (Th) 1 cytokines that favored pregnancy loss. E₂ pretreatment promoted SGK1 activation in the decidual macrophages of OVX mice in vivo. E₂ pretreatment amplified SGK1 activation in TLR4-stimulated THP-1 macrophages in vitro through the estrogen receptor beta (ERβ) and PI3K pathway. E₂-sensitive activation of SGK1 increased M2 macrophages and Th2 immune responses, which were beneficial to successful pregnancy, by inducing ARG1 and IRF4 transcription, which are implicated in normal pregnancy. The experiments on OVX mice have shown that pharmacological inhibition of E₂ promoted nuclear translocation of NF-κB in the decidual macrophages. Further more, pharmacological inhibition or knockdown of SGK1 in TLR4-stimulated THP-1 macrophages activated NF-κB by promoting its nuclear translocation, leading to increased secretion of pro-inflammatory cytokines involved in pregnancy loss.

CONCLUSION

Our findings highlighted the immunomodulatory roles of E₂-activated SGK1 in Th2 immune responses by priming anti-inflammatory M2 macrophages at the maternal-fetal interface, resulting in a balanced immune microenvironment during pregnancy. Our results suggest new perspectives on future preventative strategies for RPL.

Exosomal Mir-3613-3p derived from oxygen-glucose deprivation-treated brain microvascular endothelial cell promotes microglial M1 polarization

BACKGROUND

Brain microvascular endothelial cell (BMEC) injury can affect neuronal survival by modulating immune responses through the microenvironment. Exosomes are important vehicles of transport between cells. However, the regulation of the subtypes of microglia by BMECs through the exosome transport of microRNAs (miRNAs) has not been established.

METHODS

In this study, exosomes from normal and oxygen-glucose deprivation (OGD)-cultured BMECs were collected, and differentially expressed miRNAs were analyzed. BMEC proliferation, migration, and tube formation were analyzed using MTS, transwell, and tube formation assays. M1 and M2 microglia and apoptosis were analyzed using flow cytometry. miRNA expression was analyzed using real-time polymerase chain reaction (RT-qPCR), and IL-1β, iNOS, IL-6, IL-10, and RC3H1 protein concentrations were analyzed using western blotting.

RESULTS

We found that miR-3613-3p was enriched in BMEC exosome by miRNA GeneChip assay and RT-qPCR analysis. miR-3613-3p knockdown enhanced cell survival, migration, and angiogenesis in the OGD-treated BMECs. In addition, BMECs secrete miR-3613-3p to transfer into microglia via exosomes, and miR-3613-3p binds to the RC3H1 3' untranslated region (UTR) to reduce RC3H1 protein levels in microglia. Exosomal miR-3613-3p promotes microglial M1 polarization by inhibiting RC3H1 protein levels. BMEC exosomal miR-3613-3p reduces neuronal survival by regulating microglial M1 polarization.

CONCLUSIONS

miR-3613-3p knockdown enhances BMEC functions under OGD conditions. Interfering with miR-3613-3p expression in BMSCs reduced the enrichment of miR-3613-3p in exosomes and enhanced M2 polarization of microglia, which contributed to reduced neuronal apoptosis.

TNFα/TNFR1 signal induces excessive senescence of decidua stromal cells in recurrent pregnancy loss

Defects in decidual response are associated with adverse pregnancy outcomes which includes recurrent pregnancy loss (RPL). It is reported that cellular senescence happens during decidualization and pro-senescent decidual response in the luteal phase endometrium is related to RPL. However, the underlying mechanisms of how excessive decidual senescence takes place in RPL decidua cells remain largely unexplored. The senescent phenotype of RPL decidua and tumor necrosis factor receptor 1(TNFR1) expression were analyzed by using our previously published single-cell sequencing dataset of decidua cells from 6 RPL and 5 matched normal decidua, which were further verified by PCR and WB in decidual tissues. Effects of TNFα on the decidual stromal cells (DSCs) senescence and underlying molecular pathways were analyzed using the in vitro decidualization model of human endometrial stromal cells (HESCs). We showed that decidual stroma cells from RPL patients exhibited transcriptomic features of cellular senescence by analysis of single-cell datasets. The TNFα level and TNFR1 expression were increased in RPL decidua tissues. Furthermore, in vitro cell model demonstrated that increased TNFα induced excessive senescence during decidualization and TNFR1/p53/p16 pathway mediates TNFα-induced stromal senescence. In addition, we also found that the expression of IGFBP1 was regulated by TNFα-TNFR1 interaction during decidualization. Taken together, the present findings suggest that the increased secretion of TNFα induced stromal cell excessive senescence in RPL decidua, which is mediated via TNFR1, and thus provide a possible therapeutic target for the treatment of RPL.

Decidual macrophages in recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is defined as two or more pregnancy loss, affecting the happiness index of fertility couples. The mechanisms involved in the occurrence of RSA are not clear to date. The primary problem for the maternal immune system is how to establish and maintain the immune tolerance to the semi-allogeneic fetuses. During the pregnancy, decidual macrophages mainly play an important role in the immunologic dialogue. The purpose of this study is to explore decidual macrophages, and to understand whether there is a connection between these cells and RSA by analyzing their phenotypes and functions. Pubmed, Web of Science and Embase were searched. The eligibility criterion for this review was evaluating the literature about the pregnancy and macrophages. Any disagreement between the authors was resolved upon discussion and if required by the judgment of the corresponding author. We summarized the latest views on the phenotype, function and dysfunction of decidual macrophages to illuminate its relationship with RSA.

SEC5 is involved in M2 polarization of macrophages via the STAT6 pathway, and its dysfunction in decidual macrophages is associated with recurrent spontaneous abortion

Decidual macrophages (dMϕs) play critical roles in the establishment of microhomeostasis at the maternal-fetal interface during pregnancy. Impaired macrophage polarization during early pregnancy is associated with recurrent spontaneous abortion (RSA). In the present study, the SEC5 expression level was found to be significantly decreased in primary dMϕs of patients with RSA, and downregulation of SEC5 expression inhibited M2 polarization and STAT6 phosphorylation, whereas SEC5 overexpression in the Mϕs promoted M2 polarization and STAT6 phosphorylation in vitro. We subsequently found that SEC5 interacted with STAT6 in THP-1-derived Mϕs. The abundance of phosphorylated STAT6 (pSTAT6) protein was obviously increased, with a predominant distribution in the nucleus, after M2 polarization of Mϕs, and SEC5 protein was colocalized with pSTAT6. Moreover, a significantly reduced pSTAT6 expression level was observed in the dMϕs of patients with RSA. M2 polarization of Mϕs showed a stimulatory effect on the proliferation and invasion of human extravillous trophoblasts (EVTs) in vitro, and downregulation of SEC5 expression in Mϕs effectively reversed this effect. In a mouse model of LPS-induced early pregnancy loss, the uterine SEC5 expression level and the number of M2-Mϕs at the maternal-fetal interface were significantly reduced. More interestingly, heterozygous SEC5-deficient (SEC5^−/+) pregnant mice were more sensitive to LPS-induced pregnancy loss. Taken together, these data indicate that SEC5 participates in the regulation of M2 polarization of Mϕs by interacting with STAT6 and that decreased SEC5 expression inhibits the M2 polarization of dMϕs and results in early pregnancy loss by interfering with the physical activities of EVTs and immunotolerance at the maternal-fetal interface.