Triple-negative breast cancer (TNBC), characterized by aggressive behavior and poor prognosis, presents a formidable clinical challenge. Despite guideline endorsement of chemoimmunotherapy as a standard treatment in TNBC, durable responses remain rare, largely due to an immunologically "cold" tumor microenvironment (TME). Through integrated analysis, we identified the F-box protein FBXW5 as a tumor-intrinsic immunosuppressive regulator, whose expression is elevated in immunologically "cold" TNBC and correlates with dismal patient survival. Genetic knockdown of murine Fbxw5 suppressed tumor growth, reinvigorated CD8+ T cell-mediated antitumor immunity, and sensitized TNBC tumors to both single-agent and combined chemo-immune therapy in preclinical models. Mechanistically, FBXW5 acts within the SKP1/CUL1/F-box protein (SCF) E3 ligase complex to bind RIGI and MDA5, promoting their K27-linked polyubiquitination and subsequent SQSTM1-mediated autophagic degradation. This process blunts cytosolic RNA sensing and type I interferon (IFN-I) signaling, thereby limiting CD8+ T cell infiltration and activation. Our findings establish FBXW5 as a master regulator of the "cold" TME, presenting a potential predictive biomarker and actionable therapeutic target for enhancing chemoimmunotherapy in TNBC.

Intratumoral hypoxia is a hallmark of triple-negative breast cancer (TNBC) and induces complex biological responses, including treatment resistance and mitochondrial production of reactive oxygen species (ROS). However, the direct mechanisms through which hypoxia-induced ROS are sensed and contribute to therapeutic resistance remain elusive. ROS can regulate the function of transcription factors through oxidation of cysteine thiol groups, but the compartmentalization limits their physical interaction with transcription factors. Here, BHLHE40, a transcription factor traditionally recognized for its nuclear function, is identified as a novel mitochondrial sensor of hypoxia-induced ROS. Mitochondrial BHLHE40 experiences ROS-dependent oxidation of cysteine thiol groups and forms disulfide-linked homodimers. In addition to post-translational modification that regulates BHLHE40 protein levels, hypoxia also increases BHLHE40 mRNA levels through hypoxia-inducible factors (HIFs)-dependent transcriptional activation. These dual mechanisms of modulating BHLHE40 ensure its rapid elevation during the early stage of hypoxia. Functionally, BHLHE40 plays a critical role in hypoxia-induced radioresistance through transcriptional activation of cellular antioxidant systems and inhibition of cytotoxic effects mediated by irradiation-generated ROS. This study reveals a previously unrecognized role of BHLHE40 in sensing and regulating ROS in response to hypoxia, and highlights its potential as a therapeutic target to overcome hypoxia-promoted radioresistance in TNBC.

Triple-negative breast cancer (TNBC) is the most malignant BC subtype, and metastasis remains the major cause of poor prognosis. TGF-β plays crucial roles in TNBC metastasis, yet the underlying mechanisms remain unclear. Circular RNAs (circRNAs) are a novel type of regulatory RNA characterized by high evolutionary conservation and stability. This study aims to investigate the roles and mechanisms of circRNAs in TGF-β-induced TNBC metastasis. CircNSD2 was detected in TNBC cells through high-throughput RNA sequencing. Gain- and loss-of-function assays were performed to evaluate the role of circNSD2. Chromatin immunoprecipitation (ChIP) and luciferase assays verified the regulatory effects of TGF-β on circNSD2. RNA pulldown, proteomic analyses, and RNA immunoprecipitation were conducted to identify the downstream targets of circNSD2. CircNSD2 expression was upregulated in patients with metastatic TNBC and correlated with an unfavorable prognosis. In vitro and in vivo studies indicated that circNSD2 facilitates TGF-β-induced TNBC metastasis and EMT. Mechanistically, circNSD2 is activated by TGF-β and cyclized by KHSRP. Moreover, circNSD2 functions as a scaffold to enhance the interaction between the SRSF6 and USP10 proteins, thereby preventing K48-linked polyubiquitination of SRSF6 at lysine 16 and inhibiting its proteasomal degradation. Furthermore, stabilized SRSF6 reprogrammed TPM1 alternative splicing, which resulted in TNBC metastasis. In addition, circNSD2 promoted immune escape in TNBC by upregulating PD-L1 expression and suppressing the antitumor immunity of CD8+ T cells. Our study revealed that circNSD2 increased TNBC metastasis and immune escape by promoting the USP10/SRSF6/TPM1 axis and that circNSD2 could serve as a potential diagnostic biomarker and therapeutic target for TNBC patients.

Background Breast cancer (BC) is the most common neoplasm in women, and its growth mainly depends on estrogen, but the mechanism of estrogen in BC is still not fully understood. Circular RNAs (circRNAs) represent a novel type of regulatory RNA characterized by high evolutionary conservation and stability. This study aimed to investigate the roles and mechanisms of circRNAs in ER-positive BC. Methods CircKIAA1617 was identified through high-throughput RNA sequencing in ER-positive BC. Gain- and loss-of-function assays were performed to evaluate the functions of circKIAA1617 in ER-positive BC cells. Chromatin immunoprecipitation (ChIP) and luciferase assays verified the regulatory effects of estrogen on circKIAA1617 expression. RNA pulldown experiments, proteomic analyses, and RNA immunoprecipitation were conducted to identify the downstream targets of circKIAA1617. Results CircKIAA1617 expression was upregulated in ER-positive BC cells and tissues, indicating an unfavorable prognosis. In vitro and in vivo studies proved the circKIAA1617 increased the proliferation and stemness of ER-positive BC cells by inducing autophagy. Mechanistically, circKIAA1617 was activated by estrogen and cyclized by EIF4A3. Moreover, circKIAA1617 could act as a scaffold to enhance the interaction between the PGRMC1 and USP14 proteins, further increasing the stability of the PGRMC1 protein by decreasing its K48-linked polyubiquitination at lysine 105. In addition, autophagy activated by the circKIAA1617/USP14/PGRMC1 axis further modulated lipid metabolic reprogramming in ER-positive BC by increasing lipophagy, which accounted for the proliferation, stemness and autophagy of ER-positive BC. Conclusions Our results revealed that circKIAA1617 promoted the proliferation and stemness of BC cells by regulating USP14/PGRMC1-mediated autophagy and lipid metabolic reprogramming and could serve as a potential diagnostic biomarker for ER-positive BC.

M2-like tumor-associated macrophages (TAMs) are the main immunosuppressive cells infiltrating the tumor microenvironment (TME), the activation of which is essential for cancer progression and resistance promotion to immunotherapy. However, the regulatory mechanisms underlying TAM activation have not been fully elucidated. Utilizing a CRISPR-Cas9-based genetically engineered mouse model, we discovered that USP1fl/flLyz2cre/+ and WDR48fl/flLyz2cre/+ mice exhibited decreased tumor formation and lung metastasis. Mechanistically, the USP1-WDR48 deubiquitinase complex regulated M2-TAM activation and infiltration in the TME by modulating DDX3X ubiquitination. Specifically, this complex interacted with the N-terminal RecA-like domain 1 of DDX3X, leading to K48-linked deubiquitination and stabilization of DDX3X. Then, DDX3X promoted the translation of signaling molecules Jak1 and Rac1 via its RNA helicase activity, activating the Jak1-Stat3/6 and Rac1-Akt pathways to drive M2-TAM activation. Furthermore, combined inhibition of the USP1/WDR48 and CD47/SIRPα signaling pathways showed synergistic antitumor effects in immunocompetent mice. Notably, USP1 protein expression in tumor stromal tissues independently predicts prognosis in breast cancer patients. These findings indicated the role of the USP1-WDR48 complex as a critical molecular switch controlling TAM activation, presenting novel and promising targets for breast cancer treatment.

Triple-negative breast cancer (TNBC) is an exceptionally aggressive subtype of breast cancer. Despite the recognized interplay between tumors and tumor-associated macrophages in fostering drug resistance and disease progression, the precise mechanisms leading these interactions remain elusive. Our study revealed that the upregulation of collagen type V alpha 1 (COL5A1) in TNBC tissues, particularly in chemoresistant samples, was closely linked to an unfavorable prognosis. Functional assays unequivocally demonstrated that COL5A1 played a pivotal role in fueling cancer growth, metastasis, and resistance to doxorubicin, both in vitro and in vivo. Furthermore, we found that the cytokine IL-6, produced by COL5A1-overexpressing TNBC cells actively promoted M2 macrophage polarization. In turn, TGFβ from M2 macrophages drived TNBC doxorubicin resistance through the TGFβ/Smad3/COL5A1 signaling pathway, establishing a feedback loop between TNBC cells and macrophages. Mechanistically, COL5A1 interacted with TGM2, inhibiting its K48-linked ubiquitination-mediated degradation, thereby enhancing chemoresistance and increasing IL-6 secretion. In summary, our findings underscored the significant contribution of COL5A1 upregulation to TNBC progression and chemoresistance, highlighting its potential as a diagnostic and therapeutic biomarker for TNBC.

Japanese encephalitis virus (JEV) and dengue virus (DENV) are two major arboviruses known as significant public health issues worldwide. Arboviruses are a heterogeneous group of vector-borne viruses that are clinically associated with various consequences ranging from asymptomatic infections to serious forms of haemorrhagic fever marked by bleeding complications. Despite advancements in understanding the pathogenesis of arboviruses the molecular mechanisms underlying clinical outcomes remain incompletely understood. Autophagy, a cellular process crucial for maintaining homeostasis through the degradation and recycling of cellular components, has emerged as a key player in viral infections. Recent studies have highlighted the dual role of autophagy in modulating the host-pathogen interaction, where it may serve as both a defence mechanism against viral replication and a tool exploited by viruses to enhance survival. In the case of arboviruses, autophagy appears to influence viral replication and modulate the host immune response, contributing to both viral persistence and the extent of clinical outcomes. This review describes the role of autophagy in the pathogenesis of JEV and DENV, focusing on the molecular mechanisms that govern autophagic processes and their interaction with JEV and DENV replication. It shows that how JEV and DENV manipulates host autophagic machinery to its advantage, the impact of autophagic dysregulation on disease severity, and potential therapeutic strategies targeting autophagy to mitigate viral encephalitis. Understanding the intricate balance between autophagy and JEV and DENV may provide novel insights into therapeutic approaches for combating these viruses.

This study investigates the prognostic value of tumor-infiltrating lymphocytes (TILs) in luminal B breast cancer patients using multiphoton microscopy (MPM) and evaluates their association with 5-year disease-free survival (DFS). We obtained unlabeled MPM images from 213 patients, quantified the frequency of TILs, and assigned a TILs-score to each patient using ridge regression analysis. In addition, compared with single CLI-score model, the nomogram model, which integrated the TILs-score model with CLI-score model, further enhanced the predictive power for the luminal B subgroup. Specifically, the area under the curve (AUC) for 5-year DFS increased from 0.740 to 0.830 and hazard ratio (HR) increased from 5.31 to 7.24 in the training cohort; in the validation cohort, AUC increased from 0.716 to 0.822 and HR increased from 3.08 to 5.01. These findings suggest that the MPM-based TILs-score is a robust prognostic factor for luminal B breast cancer, potentially guiding more tailored treatment protocols.

TRIM38, an E3 ubiquitin-protein ligase, has previously been implicated in innate immune and inflammatory responses, yet its role in breast cancer regulation remains unclear. This study elucidates the suppressive function of TRIM38 in breast cancer progression. The results indicate a decreased expression of TRIM38 in breast cancer tissues compared to adjacent non-cancerous counterparts, and its reduced expression correlates with unfavorable clinical outcomes in breast cancer patients. Both in vitro and in vivo experiments demonstrate that TRIM38 inhibits breast cancer proliferation, migration, and invasion. Furthermore, an inverse regulatory relationship between TRIM38 protein level and autophagic flux is observed. Mechanistically, SQSTM1/p62 is identified as a novel substrate of TRIM38, which promotes non-degradative K63-linked ubiquitination at SQSTM1 K420 residue. This kind of ubiquitination disrupts the interaction between SQSTM1 and LC3, thereby impeding autophagic flux. Collectively, the findings underscore TRIM38 as a crucial regulator of autophagy and present novel, promising therapeutic targets for breast cancer.

Triple-negative breast cancer (TNBC) is characterized by a pronounced hypoxic tumor microenvironment, with cancer-associated fibroblasts (CAFs) serving as the predominant cellular component and playing crucial roles in regulating tumor progression. However, the mechanism by which CAFs affect the biological behavior of tumor cells in hypoxic environment remain elusive. This study employed a bead-based multiplex immunoassay to analyze a panel of cytokines/chemokines and identified colony stimulating factor 3 (CSF3) as a significantly elevated component in the secretome of hypoxic CAFs. We found that CSF3 promoted the invasive behavior of TNBC cells by activating the downstream signaling pathway of its receptor, CSF3R. RNA sequencing analysis further revealed that phosphoglucomutase 2-like 1 (PGM2L1) is a downstream target of the CSF3/CSF3R signaling, enhancing the glycolysis pathway and providing energy to support the malignant phenotype of breast cancer. In vivo, we further confirmed that CSF3 promotes TNBC progression by targeting PGM2L1. These findings suggest that targeting CSF3/CSF3R may represent a potential therapeutic approach for TNBC.

Breast cancer remains a significant global health challenge, and its mechanisms of progression and metastasis are still not fully understood. In this study, analysis of TCGA and GEO datasets revealed a significant increase in CCT2 expression in breast cancer tissues, which was associated with poor prognosis in breast cancer patients. Functional analysis revealed that CCT2 promoted breast cancer growth and metastasis through activation of the JAK2/STAT3 signaling pathway. Additionally, the E3 ubiquitin ligase Trim21 facilitated CCT2 ubiquitination and degradation, significantly reversing the protumor effects of CCT2. Most interestingly, we discovered that exosomal CCT2 derived from breast cancer cells suppressed the activation and proinflammatory cytokine secretion of CD4+ T cell. Mechanistically, exosomal CCT2 constrained Ca2+-NFAT1 signaling, thereby reducing CD40L expression on CD4+ T cell. These findings highlight CCT2 upregulation as a potential driver of breast cancer progression and immune evasion. Our study provides new insights into the molecular mechanisms underlying breast cancer progression, suggesting that CCT2 is a promising therapeutic target and prognostic predictor for breast cancer.

AbstractTriple‐negative breast cancer (TNBC) is the most malignant subtype of breast cancer. TP53, which has a mutation rate of ≈70%–80% in TNBC patients, plays oncogenic roles when mutated. However, whether circRNAs can exert their effects on TNBC through regulating mutant TP53 has not been well evaluated. In this study, circCFL1, which is highly expressed in TNBC cells and tissues and has prognostic potential is identified. Functionally, circCFL1 promoted the proliferation, metastasis and stemness of TNBC cells. Mechanistically, circCFL1 acted as a scaffold to enhance the interaction between HDAC1 and c‐Myc, further promoting the stability of c‐Myc via deacetylation‐mediated inhibition of K48‐linked ubiquitylation. Stably expressed c‐Myc further enhanced the expression of mutp53 in TNBC cells with TP53 mutations by directly binding to the promoter of TP53, which promoted the stemness of TNBC cells via activation of the p‐AKT/WIP/YAP/TAZ pathway. Moreover, circCFL1 can facilitate the immune escape of TNBC cells by promoting the expression of PD‐L1 and suppressing the antitumor immunity of CD8+ T cells. In conclusion, the results revealed that circCFL1 plays an oncogenic role by promoting the HDAC1/c‐Myc/mutp53 axis, which can serve as a potential diagnostic biomarker and therapeutic target for TNBC patients with TP53 mutations.

Peptides and proteins encoded by noncanonical open reading frames (ORFs) of circRNAs have recently been recognized to play important roles in disease progression, but the biological functions and mechanisms of these peptides and proteins are largely unknown. Here, we identified a potential coding circular RNA, circTRIM1, that was upregulated in doxorubicin-resistant TNBC cells by intersecting transcriptome and translatome RNA-seq data, and its expression was correlated with clinicopathological characteristics and poor prognosis in patients with TNBC. CircTRIM1 possesses a functional IRES element along with an 810 nt ORF that can be translated into a novel endogenously expressed protein termed TRIM1-269aa. Functionally, we demonstrated that TRIM1-269aa, which is involved in the biological functions of circTRIM1, promoted chemoresistance and metastasis in TNBC cells both in vitro and in vivo. In addition, we found that TRIM1-269aa can be packaged into exosomes and transmitted between TNBC cells. Mechanistically, TRIM1-269aa enhanced the interaction between MARCKS and calmodulin, thus promoting the calmodulin-dependent translocation of MARCKS, which further initiated the activation of the PI3K/AKT/mTOR pathway. Overall, circTRIM1, which encodes TRIM1-269aa, promoted TNBC chemoresistance and metastasis by enhancing MARCKS translocation and PI3K/AKT/mTOR activation. Our investigation has yielded novel insights into the roles of protein-coding circRNAs and supported circTRIM1/TRIM1-269aa as a novel promising prognostic and therapeutic target for patients with TNBC.

Peptides and proteins encoded by noncanonical open reading frames (ORFs) of circRNAs have recently been recognized to play important roles in disease progression, but the biological functions and mechanisms of these peptides and proteins are largely unknown. Here, we identified a potential coding circular RNA, circTRIM1, that was upregulated in doxorubicin-resistant TNBC cells by intersecting transcriptome and translatome RNA-seq data, and its expression was correlated with clinicopathological characteristics and poor prognosis in patients with TNBC. CircTRIM1 possesses a functional IRES element along with an 810 nt ORF that can be translated into a novel endogenously expressed protein termed TRIM1-269aa. Functionally, we demonstrated that TRIM1-269aa, which is involved in the biological functions of circTRIM1, promoted chemoresistance and metastasis in TNBC cells both in vitro and in vivo. In addition, we found that TRIM1-269aa can be packaged into exosomes and transmitted between TNBC cells. Mechanistically, TRIM1-269aa enhanced the interaction between MARCKS and calmodulin, thus promoting the calmodulin-dependent translocation of MARCKS, which further initiated the activation of the PI3K/AKT/mTOR pathway. Overall, circTRIM1, which encodes TRIM1-269aa, promoted TNBC chemoresistance and metastasis by enhancing MARCKS translocation and PI3K/AKT/mTOR activation. Our investigation has yielded novel insights into the roles of protein-coding circRNAs and supported circTRIM1/TRIM1-269aa as a novel promising prognostic and therapeutic target for patients with TNBC.

The structure characterization of two new polysaccharides from Agrocybe aegerita (AA-P) and Hygrophorus olivaceoalbus (HO-P) by HPGPC, GC-MS, NMR and FT-IR indicated that AA-P was composed of Galactose, Glucose and Arabinose, in the ratio of 3:2:1. Its skeleton structure was consisted of (1→4)-Arap, (1→4,6)-Glup and (1→6)-Galp with one branched chain. The HO-P was consisted of mannose, galactose and glucose in a ratio of 1:1:2. Its skeleton structure was consisted of (1→6)-Galactose residues, (→1)-glucose residues, (1→4)-glucose residues and (1→4,6)-D-mannose residues. There were two branched chains connected to the main chain. AA-P and HO-P had the best stimulation effect on B cells and RAW264.7 cells, respectively, and could both mainly by impacting and reducing G0/G1 phase which lead to a significant proliferation of B cells, T cells and RAW264.7 cells. In addition, AA-P and HO-P could significantly promote the secretion of TNF-α from T cells, the secretion of IgA, IgD, IgE, IgG and IgM from B cells, and the secretion of TNF-α from RAW264.7 cells, but neither of them could impact the secretion of IL-1β from RAW264.7 cells.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with higher aggressiveness and poorer outcomes. Recently, long non-coding RNAs (lncRNAs) have become the crucial gene regulators in the progression of human cancers. However, the function and underlying mechanisms of lncRNAs in TNBC remains unclear. Based on public databases and bioinformatics analyses, the low expression of lncRNA MIDEAS-AS1 in breast cancer tissues was detected and further validated in a cohort of TNBC tissues. The effects of MIDEAS-AS1 on proliferation, migration, invasion were determined by in vitro and in vivo experiments. RNA pull-down assay and RNA immunoprecipitation (RIP) assay were carried out to reveal the interaction between MIDEAS-AS1 and MATR3. Luciferase reporter assay, Chromatin immunoprecipitation (ChIP) and qRT-PCR were used to evaluate the regulatory effect of MIDEAS-AS1/MATR3 complex on NCALD. LncRNA MIDEAS-AS1 was significantly downregulated in TNBC, which was correlated with poor overall survival (OS) and progression-free survival (PFS) in TNBC patients. MIDEAS-AS1 overexpression remarkably inhibited tumor growth and metastasis in vitro and in vivo. Mechanistically, MIDEAS-AS1 mainly located in the nucleus and interacted with the nuclear protein MATR3. Meanwhile, NCALD was selected as the downstream target, which was transcriptionally regulated by MIDEAS-AS1/MATR3 complex and further inactivated NF-κB signaling pathway. Furthermore, rescue experiment showed that the suppression of cell malignant phenotype caused by MIDEAS-AS1 overexpression could be reversed by inhibition of NCALD. Collectively, our results demonstrate that MIDEAS-AS1 serves as a tumor-suppressor in TNBC through modulating MATR3/NCALD axis, and MIDEAS-AS1 may function as a prognostic biomarker for TNBC.

Breast cancer is the major common malignancy worldwide among women. Previous studies reported that cancer-associated fibroblasts (CAFs) showed pivotal roles in regulating tumor progression via exosome-mediated cellular communication. However, the detailed mechanism underlying the exosomal circRNA from CAFs in breast cancer progression remains ambiguous. Here, exosomal circRNA profiling of breast cancer-derived CAFs and normal fibroblasts (NFs) was detected by high-throughput sequencing, and upregulated circTBPL1 expression was identified in CAF exosomes. The exosomal circTBPL1 from CAFs could be transferred to breast cancer cells and promoted cell proliferation, migration, and invasion. Consistently, circTBPL1 knockdown in CAFs attenuated their tumor-promoting ability. Further exploration identified miR-653-5p as an inhibitory target of circTBPL1, and ectopic expression of miR-653-5p could partially reverse the malignant phenotypes induced by circTBPL1 overexpression in breast cancer. Additionally, TPBG was selected as a downstream target gene, and circTBPL1 could protect TPBG from miR-653-5p-mediated degradation, leading to enhanced breast cancer progression. Significantly, the accelerated tumor progression triggered by exosomal circTBPL1 from CAFs was confirmed in xenograft models. Taken together, these results revealed that exosomal circTBPL1 derived from CAFs contributed to cancer progression via miR-653-5p/TPBG pathway, indicating the potential of exosomal circTBPL1 as a biomarker and novel therapeutic target for breast cancer.

Chemoresistance is one of the major causes of therapeutic failure and poor prognosis for breast cancer patients, especially for triple-negative breast cancer patients. However, the underlying mechanism remains elusive. Here, we identified novel functional roles of heat shock protein beta-1 (HSPB1), regulating chemoresistance and ferroptotic cell death in breast cancer. Based on TCGA and GEO databases, HSPB1 expression was upregulated in breast cancer tissues and associated with poor prognosis of breast cancer patients, which was considered an independent prognostic factor for breast cancer. Functional assays revealed that HSPB1 could promote cancer growth and metastasis in vitro and in vivo. Furthermore, HSPB1 facilitated doxorubicin (DOX) resistance through protecting breast cancer cells from drug-induced ferroptosis. Mechanistically, HSPB1 could bind with Ikβ-α and promote its ubiquitination-mediated degradation, leading to increased nuclear translocation and activation of NF-κB signaling. In addition, HSPB1 overexpression led to enhanced secretion of IL6, which further facilitated breast cancer progression. These findings revealed that HSPB1 upregulation might be a key driver to progression and chemoresistance through regulating ferroptosis in breast cancer while targeting HSPB1 could be an effective strategy against breast cancer.

Long noncoding RNAs (lncRNAs) have been reported to be involved in various cellular processes and to participate in a variety of human diseases. Recently, increasing studies have reported that lncRNAs are related to many reproductive diseases, such as pathogenesis of recurrent pregnancy loss (RPL), preeclampsia (PE) and gestational diabetes mellitus (GDM). In this study, we aimed to investigate the effect of LINC01088 in trophoblast cells and its potential role in pathogenesis of RPL. LINC01088 was found to be upregulated in first-trimester chorionic villi tissues from RPL patients. Increased LINC01088 repressed proliferation, migration and invasion of trophoblast cells, and promoted apoptosis of trophoblast cells. Further exploration indicated that LINC01088 decreased the production of nitric oxide (NO) by binding and increasing Arginase-1 and decreasing eNOS protein levels. Importantly, JNK and p38 MAPK-signaling pathways were active after overexpression of LINC01088. In conclusion, our studies demonstrated that LINC01088 plays an important role in the pathogenesis of RPL, and is a potential therapeutic target for the treatment of RPL.

Accumulation of dendritic cells (DCs) is a special characteristic of the decidual microenvironment. Decidua-infiltrated DCs show unique phenotypes and functions that promote the establishment of fetal-maternal tolerance. However, the regulatory mechanisms yet to be fully investigated. Decidual stromal cells (DSCs) are the major cellular component of decidua tissue. The interactions between DSCs and decidua-infiltrated immunocytes dictate immune tolerance in early pregnancy. Therefore, in the present study, we explore the effect of early pregnancy DSCs on monocyte-derived DCs and the relevant mechanisms. DSC-conditioned DCs showed altered phenotypes, secretion profiles and Th2 priming potential. G-CSF concentration was significantly up-regulated in the co-culture supernatant between DSCs and DCs. Supplementation of G-CSF neutralizing antibody partly reversed the reprogramming of DCs mediated by DSCs. Furthermore, G-CSF production was promoted by IL-1β, which was mainly produced by DCs and significantly up-regulated after their cultivation with DSCs. Interestingly, the effects of DSC on IL-1β production of DCs occurred in their immature stage but not their mature stage. Lastly, no significant difference of G-CSF was found in DSCs from healthy early pregnancy women and spontaneous abortions (SA) patients. However, DSCs from SA patients secreted less G-CSF in response to exogenous rhIL-1β or DC cultivation. In conclusion, our study bolster the understanding of the decidual immunomodulatory microenvironment during early pregnancy, and brings new insight into the potential clinical value of G-CSF in pregnancy disorders.