The effects and mechanisms of GM-CSF on endometrial regeneration

Granulocyte-macrophage colony-stimulating factor promotes endometrial repair after injury by regulating macrophages in mice

Intrauterine adhesion (IUA) caused by endometrial injury is a common cause of female infertility and is challenging to treat. Macrophages play a critical role in tissue repair and cyclical endometrial regeneration. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has significant reparative and anti-fibrotic effects in various tissues. However, there is limited research on the role of GM-CSF in the repair of endometrial injury and the involvement of macrophages in GM-CSF-mediated endometrial repair. In this study, using a mouse model of endometrial scratching injury, we found that GM-CSF treatment accelerated the repair of endometrial injury and improved fertility. At the molecular level, we observed that GM-CSF can downregulate the transcript levels of tumor necrosis factor (TNF) in mouse bone marrow-derived macrophages (BMDMs) stimulated by lipopolysaccharide (LPS) and upregulate the expression of Arginase-1 (Arg-1) and mannose receptor C-type 1 (MRC1). Importantly, during the early and middle stages of injury, GM-CSF increased the proportion of M1-like, M2-like, and M1/M2 mixed macrophages, while in the late stage of injury, GM-CSF facilitated a decline in the number of M2-like macrophages. These findings suggest that GM-CSF may promote endometrial repair by recruiting macrophages and modulating the LPS-induced M1-like macrophages into a less inflammatory phenotype. These insights have the potential to contribute to the development of novel therapeutic approaches for the treatment of intrauterine adhesion and related infertility.

Targeting CD301+ macrophages inhibits endometrial fibrosis and improves pregnancy outcome

Macrophages are a key and heterogeneous cell population involved in endometrial repair and regeneration during the menstrual cycle, but their role in the development of intrauterine adhesion (IUA) and sequential endometrial fibrosis remains unclear. Here, we reported that CD301+ macrophages were significantly increased and showed their most active interaction with profibrotic cells in the endometria of IUA patients compared with the normal endometria by single-cell RNA sequencing, bulk RNA sequencing, and experimental verification. Increasing CD301+ macrophages promoted the differentiation of endometrial stromal cells into myofibroblasts and resulted in extracellular matrix accumulation, which destroyed the physiological architecture of endometrial tissue, drove endometrial fibrosis, and ultimately led to female infertility or adverse pregnancy outcomes. Mechanistically, CD301+ macrophages secreted GAS6 to activate the AXL/NF-κB pathway, upregulating the profibrotic protein synthesis. Targeted deletion of CD301+ macrophages or inhibition of AXL by Bemcentinib blunted the pathology and improved the outcomes of pregnancy in mice, supporting the therapeutic potential of targeting CD301+ macrophages for treating endometrial fibrosis.

Aldehyde-mediated adaptive membranes with self-healing and antimicrobial properties for endometrial repair

Traditional treatment methods for irreversible endometrial damage face a number of challenges in clinical practice, the most important of which are bacterial infection and the inability to restore endometrial function. By modifying glucan, oxidized dextran (OD) with multifunctional aldehyde groups was obtained in this study. Based on the dynamic Schiff base reaction between gelatin (GA) and OD, a GA-OD adaptive membrane with good biocompatibility, self-healing, biodegradability, and antimicrobial properties was created. In vitro studies revealed that GA and OD cross-linking overcame GA's low gel temperature, accelerated gelling, and improved mechanical properties, hydrophilicity, and degradability. The dynamic bond formed by the reaction between GA and OD caused the GA-OD film to self-heal. Meanwhile, the GA-OD membrane had antibacterial properties. To assess the repair effect of GA-OD film, an in vivo rat endometrial injury model filled with GA-OD adaptive membrane was created. According to the results of the study, the GA-OD membrane was biocompatible, and the uterine tissue did not have edema and inflammation. Further study on the postoperative endometrial regeneration effect of GA-OD material showed that it had an excellent ability for epithelial reconstruction and cell proliferation. As a result, the use of GA-OD composite film in endometrial repair has promising therapeutic implications.

Role of noncoding RNA in the pathophysiology and treatment of intrauterine adhesion

Intrauterine adhesion (IUA) is one of the most common diseases of the reproductive system in women. It is often accompanied by serious clinical problems that damage reproductive function, such as menstrual disorder, infertility, or recurrent abortion. The clinical effect of routine treatment is not ideal, and the postoperative recurrence rate is still very high. Therefore, exploring the pathological mechanism of IUA and finding new strategies for the effective prevention and treatment of IUA are needed. The main pathological mechanism of IUA is endometrial fibrosis and scar formation. Noncoding RNA (ncRNA) plays an important role in the fibrosis process, which is one of the latest research advances in the pathophysiology of IUA. Moreover, the exosomal miRNAs derived from mesenchymal stem cells can be used to improve IUA. This paper reviewed the role of ncRNAs in IUA pathogenesis, summarized the core pathways of endometrial fibrosis regulated by ncRNAs, and finally introduced the potential of ncRNAs as a therapeutic target.

Effects of N Acetylcysteine on the Expression of Genes Associated with Reproductive Performance in the Goat Uterus during Early Gestation

Simple Summary

The uterus is an important place for mammals to nurture new life, and improving the physiological function of the uterus is important for improving the reproductive efficiency of mammals. NAC is a small-molecule antioxidant with a positive regulatory effect on mammalian reproductive performance. We found that NAC can alter the expression of uterine genes in goats in early gestation. These DEGs may regulate uterine performance in early pregnancy in goats by participating in signalling pathways related to reproductive regulation, resistance to oxidative stress, immune regulation, angiogenesis and development, cytokines, and cell adhesion. These findings provide a fundamental reference for the modulation of reproductive performance in goats in early gestation by NAC.

Abstract

N acetylcysteine (NAC) affects antioxidation and reactive oxygen species scavenging in the body and thereby promotes embryonic development and implantation and inhibits inflammation. The mechanism through which NAC regulates reproductive performance in the uteri of goats during early gestation remains unclear. In this study, the treatment group was fed 0.07% NAC for the first 35 days of gestation, whereas the control group received no NAC supplementation. The regulatory genes and key pathways associated with goat reproductive performance under NAC supplementation were identified by RNA-seq. RT–qPCR was used to verify the sequencing results and subsequently construct tissue expression profiles of the relevant genes. RNA-seq identified 19,796 genes coexpressed in the control and treatment groups and 1318 differentially expressed genes (DEGs), including 787 and 531 DEGs enriched in the treatment and control groups, respectively. A GO analysis revealed that the identified genes mapped to pathways such as cell activation, cytokine production, cell mitotic processes, and angiogenesis, and a KEGG enrichment analysis showed that the DEGs were enriched in pathways associated with reproductive regulation, immune regulation, resistance to oxidative stress, and cell adhesion. The RT–qPCR analysis showed that BDNF and CSF-1 were most highly expressed in the uterus, that WIF1 and ESR2 showed low expression in the uterus, and that CTSS, PTX3, and TGFβ-3 were most highly expressed in the oviduct, which indicated that these genes may be directly or indirectly involved in the modulation of reproduction in early-gestation goats. These findings provide fundamental data for the NAC-mediated modulation of the reproductive performance of goats during early gestation.

EGCG exposure during pregnancy affects uterine histomorphology in F1 female mice and the underlying mechanisms

Although epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to have many benefits, the effect of EGCG exposure in utero on adult uterine development is unclear. In this study, pregnant C57BL/6 mice were exposed to 1 mg/kg body weight (bw) EGCG dissolved in drinking water from gestational days 0.5-16.5. A significant decrease in uterine weight was observed in the adult female mice, accompanied by uterine atrophy, inflammation, and fibrosis in the endometrium. Uterine atrophy was attributed to the thinning of the endometrial stromal layer and a significant reduction in endometrial cell proliferation. The expression levels of related proteins in the NF-κB and RAF/MEK/ERK signaling pathways were significantly increased, which might be responsible for the occurrence of inflammation. Activation of the transforming growth factor beta (TGF-β1)/Smad signaling pathway might be involved in the development of endometrial fibrosis. The changes in the expression of estrogen receptor α, β (ERα, ERβ), progesterone receptor (PGR), and androgen receptor (AR) might lead to changes in the aforementioned signaling pathways. The promoter region methylation level of Esr2 was increased, and the expression of DNMT3A was evaluated. Our study indicates a risk of EGCG intake during pregnancy affecting uterine development in offspring.

Surface structure change properties: Auto-soft bionic fibrous membrane in reducing postoperative adhesion

Peritoneal adhesion is the most common adverse effect following abdominal surgery or inflammation. The occurrence in clinical trials has been successfully reduced using barriers. However, the shortcomings of frequently used adhesion barriers, such as rapid degradation rate of gel barrier and inadequate operation ability of solid barrier, cannot be ignored. In this study, a fibrous membrane with an ECM-like structure was prepared. The adhesion properties were reduced significantly by changing the surface structure. The fibrous membrane caused less inflammatory response and much less peripheral adhesion and intestinal obstruction compared to the casting film and the commercial film with smooth surface, though with the same components. Because of the auto-soft bionic structure and similarity in the mechanical modulus of the tissues, the fibrous membrane was more flexible when it adhered to the tissues, showed excellent effectiveness and biocompatibility. In addition to the rat and miniature pig models, a randomized, placebo-controlled, and multicenter clinical pilot study with 150 patients confirmed that because of its flexibility, biodegradability, and similarity to mechanical modulus and structure with tissues involved, the fibrous membrane served as a favorable implant for preventing post-operation adhesion.

•

The fibrous membrane with an ECM-like structure can be used the adhesion barrier.

•

The fibrous membrane, with auto-soft bionic structure and similar mechanical modulus to the tissues, was flexible.

•

The fibrous membrane caused less inflammatory response and intestinal obstruction.

Synergistic regenerative therapy of thin endometrium by human placenta-derived mesenchymal stem cells encapsulated within hyaluronic acid hydrogels

Background

Thin endometrium is a primary cause of defective endometrial receptivity, resulting in infertility or recurrent miscarriage. Much effort has been devoted toward regenerating thin endometrium by stem cell-based therapies. The human placenta-derived mesenchymal stem cells (HP-MSCs) are emerging alternative sources of MSCs with various advantages. To maximize their retention inside the uterus, we loaded HP-MSCs with cross-linked hyaluronic acid hydrogel (HA hydrogel) to investigate their therapeutic efficacy and possible underlying mechanisms.

Methods

Ethanol was injected into the mice uterus to establish the endometrium-injured model. The retention time of HP-MSCs and HA hydrogel was detected by in vivo imaging, while the distribution of HP-MSCs was detected by immunofluorescence staining. Functional restoration of the uterus was assessed by testing embryo implantation rates. The endometrial morphological alteration was observed by H&E staining, Masson staining, and immunohistochemistry. In vitro studies were further conducted using EdU, transwell, tube formation, and western blot assays.

Results

Instilled HP-MSCs with HA hydrogel (HP-MSCs-HA) exhibited a prolonged retention time in mouse uteri than normal HP-MSCs. In vivo studies showed that the HP-MSCs-HA could significantly increase the gland number and endometrial thickness (P < 0.001, P < 0.05), decrease fibrous area (P < 0.0001), and promote the proliferation and angiogenesis of endometrial cells (as indicated by Ki67 and VEGF, P < 0.05, P < 0.05, respectively) in mice injured endometrium. HP-MSCs-HA could also significantly improve the embryo implantation rate (P < 0.01) compared with the ethanol group. Further mechanistic study showed the paracrine effects of HP-MSCs. They could not only promote the proliferation and migration of human endometrial stromal cells via the JNK/Erk1/2-Stat3-VEGF pathway but also facilitate the proliferation of glandular cells via Jak2-Stat5 and c-Fos-VEGF pathway. In turn, the increased VEGF in the endometrium promoted the angiogenesis of endothelial cells.

Conclusion

Our study suggested the potential therapeutic effects and the underlying mechanisms of HP-MSCs-HA on treating thin endometrium. HA hydrogel could be a preferable delivery method for HP-MSCs, and the strategy represents a promising therapeutic approach against endometrial injury in clinical settings.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02717-2.

Understanding the Impact of Uterine Fibroids on Human Endometrium Function

Uterine fibroids (leiomyomas) are the most common benign gynecological tumors in women of reproductive age worldwide. They cause heavy menstrual bleeding, usually leading to severe anemia, pelvic pain/pressure, infertility, and other debilitating morbidities. Fibroids are believed to be monoclonal tumors arising from the myometrium, and recent studies have demonstrated that fibroids actively influence the endometrium globally. Studies suggest a direct relationship between the number of fibroids removed and fertility problems. In this review, our objective was to provide a complete overview of the origin of uterine fibroids and the molecular pathways and processes implicated in their development and growth, which can directly affect the function of a healthy endometrium. One of the most common characteristics of fibroids is the excessive production of extracellular matrix (ECM) components, which contributes to the stiffness and expansion of fibroids. ECM may serve as a reservoir of profibrotic growth factors such as the transforming growth factor β (TGF-β) and a modulator of their availability and actions. Fibroids also elicit mechanotransduction changes that result in decreased uterine wall contractility and increased myometrium rigidity, which affect normal biological uterine functions such as menstrual bleeding, receptivity, and implantation. Changes in the microRNA (miRNA) expression in fibroids and myometrial cells appear to modulate the TGF-β pathways and the expression of regulators of ECM production. Taken together, these findings demonstrate an interaction among the ECM components, TGF-β family signaling, miRNAs, and the endometrial vascular system. Targeting these components will be fundamental to developing novel pharmacotherapies that not only treat uterine fibroids but also restore normal endometrial function.

Integrated Transcriptomic Analysis of the miRNA-mRNA Interaction Network in Thin Endometrium

Although the thin endometrium (TE) has been widely recognized as a critical factor in implantation failure, the contribution of miRNA-mRNA regulatory network to the development of disease etiology remains to be further elucidated. This study performed an integrative analysis of the miRNA-mRNA expression profiles in the thin and adjacent normal endometrium of eight patients with intrauterine adhesion to construct the transcriptomic regulatory networks. A total of 1,093 differentially expressed genes (DEGs) and 72 differentially expressed miRNAs (DEMs) were identified in the thin adhesive endometrium of the TE group compared with the control adjacent normal endometrial cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the DEGs and the target genes of DEM were significantly enriched in angiogenesis, cell growth regulation, and Wnt signaling pathway. Multiple hub genes (CAV1, MET, MAL2, has-mir-138, ARHGAP6, CLIC4, RRAS, AGFG1, has-mir-200, and has-mir-429) were identified by constructing the miRNA-mRNA regulatory networks. Furthermore, a miRNA-mRNA pathway function analysis was conducted, and the hub genes were enriched in the FoxO signaling pathway, cell growth regulation, inflammatory response regulation, and regulation of autophagy pathways. Our study is the first to perform integrated mRNA-seq and miRNA-seq analyses in the thin adhesive endometrium and the control adjacent normal endometrial cells. This study provides new insights into the molecular mechanisms underlying the formation of thin endometrium.