Treatment of experimental colitis by endometrial regenerative cells through regulation of B lymphocytes in mice

Upregulation of TCPTP in Macrophages Is Involved in IL-35 Mediated Attenuation of Experimental Colitis

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease with complex etiology. Interleukin-35 (IL-35), as a cytokine with immunomodulatory function, has been shown to have therapeutic effects on UC, but its mechanism is not yet clear. Therefore, we constructed Pichia pastoris stably expressing IL-35 which enables the cytokines to reach the diseased mucosa, and explored whether upregulation of T-cell protein tyrosine phosphatase (TCPTP) in macrophages is involved in the mechanisms of IL-35-mediated attenuation of UC. After the successful construction of engineered bacteria expressing IL-35, a colitis model was successfully induced by giving BALB/c mice a solution containing 3% dextran sulfate sodium (DSS). Mice were treated with Pichia/IL-35, empty plasmid-transformed Pichia (Pichia/0), or PBS by gavage, respectively. The expression of TCPTP in macrophages (RAW264.7, BMDMs) and intestinal tissues after IL-35 treatment was detected. After administration of Pichia/IL-35, the mice showed significant improvement in weight loss, bloody stools, and shortened colon. Colon pathology also showed that the inflammatory condition of mice in the Pichia/IL-35 treatment group was alleviated. Notably, Pichia/IL-35 treatment not only increases local M2 macrophages but also decreases the expression of inflammatory cytokine IL-6 in the colon. With Pichia/IL-35 treatment, the proportion of M1 macrophages, Th17, and Th1 cells in mouse MLNs were markedly decreased, while Tregs were significantly increased. In vitro experiments, IL-35 significantly promoted the expression of TCPTP in macrophages stimulated with LPS. Similarly, the mice in the Pichia/IL-35 group also expressed more TCPTP than that of the untreated group and the Pichia/0 group.

Melatonin pretreatment improves endometrial regenerative cell-mediated therapeutic effects in experimental colitis

BACKGROUND

Endometrial regenerative cells (ERCs) have been proven to be an effective strategy for attenuating experimental colitis, but the complex in vivo microenvironment such as oxidative stress may largely limit and weaken ERC efficacy. Melatonin (MT) works as an anti-oxidative agent in a variety of preclinical diseases, and has been identified to promote mesenchymal stem cell-mediated therapeutic effects in different diseases. However, the ability of MT to enhance ERC-mediated effects in colitis is currently poorly understood.

METHODS

Menstrual blood was collected from healthy female volunteers to obtain ERCs and identified. In vitro, H2O2-induced oxidative stress was introduced to test if MT could prevent ERCs from damage through detection of intracellular reactive oxidative species (ROS) and apoptosis assay. In vivo, dextran sodium sulfate (DSS)-induced acute colitis was treated by ERCs and MT-primed ERCs, therapeutic effects were assayed by the disease activity index (DAI), histological features, and macrophage and CD4+ T cell in the spleen and colon, and cytokine profiles in the sera and colon were also measured.

RESULTS

In vitro, ERCs that underwent MT-precondition were found to possess more anti-oxidative potency in comparison to naïve ERCs, which were characterized by decreased apoptosis rate and intracellular ROS under H2O2 stimulation. In vivo, MT pretreatment can significantly enhance the therapeutic effects of ERCs in the attenuation of experimental colitis, including decreased DAI index and damage score. In addition, MT pretreatment was found to promote ERC-mediated inhibition of Th1, Th17, and M1 macrophage and pro-inflammatory cytokines, increase of Treg, and immunomodulation of cytokines in the spleen and colon.

CONCLUSIONS

MT pretreatment facilitates the promotion of cell viability under oxidative stress in vitro, while also enhancing ERC-mediated therapeutic effects in experimental colitis.

5-HT induces regulatory B cells in fighting against inflammation-driven ulcerative colitis

Serotonin (5-hydroxytryptamine or 5-HT) is a neuroendocrine peptide endowed with immunomodulatory functions. Regulatory B cells (Bregs) play an important role in maintaining intestinal immune homeostasis. We analyzed the differences of 5-HT and Bregs between peripheral blood of ulcerative colitis (UC) and healthy controls (HC). Besides, 5-HT-treated B cells were adoptively transferred into colitis mice to elucidate the role of 5-HT in regulating Bregs. The level of serum 5-HT and IL-10 in UC patients was lower and both were negatively correlated with disease activity. 5-HT7 receptor (5-HT7R) was higher expressed on Bregs in UC. 5-HT promoted IL-10 production in Bregs through the activation of STAT3. And adoptive transfer of 5-HT-treated B cells alleviated intestinal inflammation via inducing IL-10-producing B cells in mice. Our results suggest that 5-HT/5-HT7R signaling pathway facilitate functional Bregs in constraining inflammation in UC, which may be a new potential prospect in the treatment of UC.

Stem Cell Therapy in Inflammatory Bowel Disease: A Review of Achievements and Challenges

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a group of chronic inflammatory diseases of the gastrointestinal tract. Repeated inflammation can lead to complications, such as intestinal fistula, obstruction, perforation, and bleeding. Unfortunately, achieving durable remission and mucosal healing (MH) with current treatments is difficult. Stem cells (SCs) have the potential to modulate immunity, suppress inflammation, and have anti-apoptotic and pro-angiogenic effects, making them an ideal therapeutic strategy to target chronic inflammation and intestinal damage in IBD. In recent years, hematopoietic stem cells (HSCs) and adult mesenchymal stem cells (MSCs) have shown efficacy in treating IBD. In addition, numerous clinical trials have evaluated the efficiency of MSCs in treating the disease. This review summarizes the current research progress on the safety and efficacy of SC-based therapy for IBD in both preclinical models and clinical trials. We discuss potential mechanisms of SC therapy, including tissue repair, paracrine effects, and the promotion of angiogenesis, immune regulation, and anti-inflammatory effects. We also summarize current SC engineering strategies aimed at enhancing the immunosuppressive and regenerative capabilities of SCs for treating intestinal diseases. Additionally, we highlight current limitations and future perspectives of SC-related therapy for IBD.

CD73 mediated host purinergic metabolism in intestine contributes to the therapeutic efficacy of a novel mesenchymal-like endometrial regenerative cells against experimental colitis

Background

The disruption of intestinal barrier functions and the dysregulation of mucosal immune responses, mediated by aberrant purinergic metabolism, are involved in the pathogenesis of inflammatory bowel diseases (IBD). A novel mesenchymal-like endometrial regenerative cells (ERCs) has demonstrated a significant therapeutic effect on colitis. As a phenotypic marker of ERCs, CD73 has been largely neglected for its immunosuppressive function in regulating purinergic metabolism. Here, we have investigated whether CD73 expression on ERCs is a potential molecular exerting its therapeutic effect against colitis.

Methods

ERCs either unmodified or with CD73 knockout (CD73-/-ERCs), were intraperitoneally administered to dextran sulfate sodium (DSS)-induced colitis mice. Histopathological analysis, colon barrier function, the proportion of T cells, and maturation of dendritic cells (DCs) were investigated. The immunomodulatory effect of CD73-expressing ERCs was evaluated by co-culture with bone marrow-derived DCs under LPS stimulation. FACS determined DCs maturation. The function of DCs was detected by ELISA and CD4+ cell proliferation assays. Furthermore, the role of the STAT3 pathway in CD73-expressing ERCs-induced DC inhibition was also elucidated.

Results

Compared with untreated and CD73-/-ERCs-treated groups, CD73-expressing ERCs effectively attenuated body weight loss, bloody stool, shortening of colon length, and pathological damage characterized by epithelial hyperplasia, goblet cell depletion, the focal loss of crypts and ulceration, and the infiltration of inflammatory cells. Knockout of CD73 impaired ERCs-mediated colon protection. Surprisingly, CD73-expressing ERCs significantly decreased the populations of Th1 and Th17 cells but increased the proportions of Tregs in mouse mesenteric lymph nodes. Furthermore, CD73-expressing ERCs markedly reduced the levels of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α) and increased anti-inflammatory factors (IL-10) levels in the colon. CD73-expressing ERCs inhibited the antigen presentation and stimulatory function of DCs associated with the STAT-3 pathway, which exerted a potent therapeutic effect against colitis.

Conclusions

The knockout of CD73 dramatically abrogates the therapeutic ability of ERCs for intestinal barrier dysfunctions and the dysregulation of mucosal immune responses. This study highlights the significance of CD73 mediates purinergic metabolism contributing to the therapeutic effects of human ERCs against colitis in mice.

Aberrant epigenetic regulation of estrogen and progesterone signaling at the level of endometrial/endometriotic tissue in the pathomechanism of endometriosis

Endometriosis is a term referring to a condition whereby the endometrial tissue is found outside the uterine cavity. This progressive and debilitating condition affects up to 15% of women of reproductive age. Due to the fact that endometriosis cells may express estrogen receptors (ERα, Erβ, GPER) and progesterone (P4) receptors (PR-A, PR-B), their growth, cyclic proliferation, and breakdown are similar to the processes occurring in the endometrium. The underlying etiology and pathogenesis of endometriosis are still not fully explained. The retrograde transport of viable menstrual endometrial cells with the retained ability to attach within the pelvic cavity, proliferate, differentiate and invade into the surrounding tissue explains the most widely accepted implantation theory. Endometrial stromal cells (EnSCs) with clonogenic potential constitute the most abundant population of cells within endometrium that resemble the properties of mesenchymal stem cells (MSCs). Accordingly, formation of the endometriotic foci in endometriosis may be due to a kind of EnSCs dysfunction. Increasing evidence indicates the underestimated role of epigenetic mechanisms in the pathogenesis of endometriosis. Hormone-mediated epigenetic modifications of the genome in EnSCs or even MSCs were attributed an important role in the etiopathogenesis of endometriosis. The roles of excess estrogen exposure and P4 resistance were also found to be crucial in the development of epigenetic homeostasis failure. Therefore, the aim of this review was to consolidate the current knowledge regarding the epigenetic background of EnSCs and MSCs and the changed properties due to estrogen/P4 imbalances in the context of the etiopathogenesis of endometriosis.

Sustainable Production and Activity Determination of Serum-Free Conditioned Medium from Menstrual Blood-Derived Endometrial Stem Cells

Mesenchymal stem cells (MSCs) have exhibited great potential as a regenerative medicine, and MSC-derived paracrine effects, mainly including the secretion of various bioactive factors, play critical roles in MSC-based therapies. MSC-derived serum-free conditioned medium (MSC-CM) is defined as the secretome of MSC-derived bioactive factors and is considered a new cell-free therapeutic agent for disease treatment. However, the MSC-CM used in previous studies was prepared by a nearly disposable method that the MSCs were discarded after preparing MSC-CM, and the preparation time was variable; simultaneously, the viability changes of MSCs after MSC-CM preparation are still unknown. Therefore, this study takes MenSCs as a research project and aims to explore the suitable period of sustainable MenSC-CM preparation rather than using a disposable method. As expected, our results confirmed that MenSC-CM improves viability of both naïve targeted cells and H₂O₂-injured targeted cells, and suggested that 36 h is suitable for sustainable MenSC-CM preparation in which the angiogenic factors almost reach to the peak. Simultaneously, the MenSCs used to prepare the MenSC-CM for 36 h also maintained preferable cell viability and could be sustainably used for further MenSC-CM preparation. Moreover, the in vivo results further confirmed the improvement of MenSC-CM on promoting skin wound healing. Consequently, our results not only provide support for optimizing MSC-CM sustainable preparation based on various MSCs but also promote the comprehensive application of MenSCs in the clinic.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Mesenchymal (Stem) Stromal Cells Based as New Therapeutic Alternative in Inflammatory Bowel Disease: Basic Mechanisms, Experimental and Clinical Evidence, and Challenges

Inflammatory bowel diseases (IBD) are an example of chronic diseases affecting 40% of the population, which involved tissue damage and an inflammatory process not satisfactorily controlled with current therapies. Data suggest that mesenchymal stem cells (MSC) may be a therapeutic option for these processes, and especially for IBD, due to their multifactorial approaches such as anti-inflammatory, anti-oxidative stress, anti-apoptotic, anti-fibrotic, regenerative, angiogenic, anti-tumor, or anti-microbial. However, MSC therapy is associated with important limitations as safety issues, handling difficulties for therapeutic purposes, and high economic cost. MSC-derived secretome products (conditioned medium or extracellular vesicles) are therefore a therapeutic option in IBD as they exhibit similar effects to their parent cells and avoid the issues of cell therapy. In this review, we proposed further studies to choose the ideal tissue source of MSC to treat IBD, the implementation of new standardized production strategies, quality controls and the integration of other technologies, such as hydrogels, which may improve the therapeutic effects of derived-MSC secretome products in IBD.

Stromal cells of the endometrium and decidua: in search of a name and an identity

Human endometrial and decidual stromal cells are the same cells in different environments (non-pregnancy and pregnancy, respectively). Although some authors consider decidual stromal cells to arise solely from the differentiation of endometrial stromal cells, this is a debatable issue given that decidualization processes do not end with the formation of the decidua, as shown by the presence of stromal cells from both the endometrium and decidua in both undifferentiated (non-decidualized) and decidualized states. Furthermore, recent functional and transcriptomic results have shown that there are differences in the decidualization process of endometrial and decidual stromal cells, with the latter having a greater decidualization capacity than the former. These differences suggest that in the terminology and study of their characteristics, endometrial and decidual stromal cells should be clearly distinguished, as should their undifferentiated or decidualized status. There is, however, considerable confusion in the designation and identification of uterine stromal cells. This confusion may impede a judicious understanding of the functional processes in normal and pathological situations. In the present article we analyse the different terms used in the literature for different types of uterine stromal cells, and propose that a combination of differentiation status (undifferentiated, decidualized) and localization (endometrium, decidua) criteria should be used to arrive at a set of accurate, unambiguous terms. The cell identity of uterine stromal cells is also a debatable issue: phenotypic, functional and transcriptomic studies in recent decades have related these cells to different established cells. We discuss the relevance of these associations in normal and pathological situations.

Therapeutic Potential of Menstrual Blood-Derived Stem Cell Transplantation for Intrauterine Adhesions

An increasing number of women experience intrauterine adhesion as a result of intrauterine operations, such as induced abortion, which can cause infertility, recurrent abortion and amenorrhea. Although some strategies have been applied clinically, such as hysteroscopy adhesiolysis of intrauterine adhesions, the results have not been promising. As regenerative medicine develops, research on menstrual blood-derived stem cell transplantation is increasing due to the properties of these cells, including self-renewal, differentiation, angiogenesis, anti-inflammation and immunomodulation. As a result, menstrual blood-derived stem cells may be an ideal cell source for the treatment of intrauterine adhesion. Excitingly, it has been reported that autologous menstrual blood stem cells could recovery injured endometrium and improve infertility in patients with refractory intrauterine adhesion. In this review, we discuss the possible potential of menstrual blood-derived stem cell transplantation for intrauterine adhesion, including the antifibrosis, angiogenesis, anti-inflammation and immunoregulation properties of the cells, which brings hopes for clinical therapy.

Endometrial Regenerative Cell-Derived Conditioned Medium Alleviates Experimental Colitis

Background

Traditional interventions can play a certain role in attenuating ulcerative colitis (UC), known as one type of inflammatory bowel diseases, but sometimes are not effective. Endometrial regenerative cells (ERCs) have been shown to exert immunosuppressive effects in different models of inflammation, and stem cell-derived conditioned media (CM) have advantages over cell therapy in terms of easy access and direct action. However, whether ERC-CM could alleviate colitis remains unclear and will be explored in this study.

Methods

Menstrual blood was collected from healthy female volunteers to obtain ERCs and ERC-CM. Acute colitis was induced by 3% dextran sodium sulfate (DSS), and ERC-CM was injected on days 4, 6, and 8, respectively, after induction. The disease activity index was calculated through the record of weight change, bleeding, and fecal viscosity during the treatment process. Histological features, macrophage and CD4⁺ T cell in the spleen and colon, and cytokine profiles in the sera and colon were measured. In addition, an in vitro lymphocyte proliferation assay was measured by using a CCK-8 kit in this study.

Results

ERC-CM treatment significantly improved the symptoms and histological changes in colitis mice. ERC-CM increased the percentage of Tregs in the spleen and colon but decreased the percentages of M1 macrophages and Th1 and Th17 cells in the spleen and decreased the population of Th17 cells in the colon. In addition, ERC-CM treatment decreased the local expression of TNF-α, IL-6, and iNOS in the colon. Furthermore, ERC-CM increased the levels of anti-inflammatory cytokines IL-10 and IL-27 but decreased proinflammatory cytokines IL-6 and IL-17 in the sera. In addition, ERC-CM significantly inhibited ConA-induced mouse lymphocyte proliferation in vitro.

Conclusion

The results suggest that ERC-CM can exert similar therapeutic effects as ERCs and could be explored for future application of cell-free therapy in the treatment of colitis.

Understanding menstrual blood-derived stromal/stem cells: Definition and properties. Are we rushing into their therapeutic applications?

Cells with mesenchymal stem cell properties have been identified in menstrual blood and termed menstrual blood-derived stem/stromal cells (MenSCs). MenSCs have been proposed as ideal candidates for cell-based therapy in regenerative medicine and immune-related diseases. However, MenSCs identity has been loosely defined so far and there is controversy regarding their cell markers and differentiation potential. In this review, we outline the origin of MenSCs in the context of regenerating human endometrium, with attention to endometrial eMSCs as reference cells to understand MenSCs. We summarize the cell identity markers analyzed and the immunomodulatory and reparative properties reported. We also address the recent use of MenSCs in cell reprogramming. The main goal of this review is to contribute to the understanding of the identity and properties of MenSCs as well as to identify potential caveats and new venues that deserve to be explored to strengthen their potential applications.

Endometrial stem/progenitor cells and their roles in immunity, clinical application, and endometriosis

Endometrial stem/progenitor cells have been proved to exist in periodically regenerated female endometrium and can be divided into three categories: endometrial epithelial stem/progenitor cells, CD140b+CD146+ or SUSD2+ endometrial mesenchymal stem cells (eMSCs), and side population cells (SPs). Endometrial stem/progenitor cells in the menstruation blood are defined as menstrual stem cells (MenSCs). Due to their abundant sources, excellent proliferation, and autotransplantation capabilities, MenSCs are ideal candidates for cell-based therapy in regenerative medicine, inflammation, and immune-related diseases. Endometrial stem/progenitor cells also participate in the occurrence and development of endometriosis by entering the pelvic cavity from retrograde menstruation and becoming overreactive under certain conditions to form new glands and stroma through clonal expansion. Additionally, the limited bone marrow mesenchymal stem cells (BMDSCs) in blood circulation can be recruited and infiltrated into the lesion sites, leading to the establishment of deep invasive endometriosis. On the other hand, cell derived from endometriosis may also enter the blood circulation to form circulating endometrial cells (CECs) with stem cell-like properties, and to migrate and implant into distant tissues. In this manuscript, by reviewing the available literature, we outlined the characteristics of endometrial stem/progenitor cells and summarized their roles in immunoregulation, regenerative medicine, and endometriosis, through which to provide some novel therapeutic strategies for reproductive and cancerous diseases.

Small extracellular vesicles from menstrual blood-derived mesenchymal stem cells (MenSCs) as a novel therapeutic impetus in regenerative medicine

Menstrual blood-derived mesenchymal stem cells (MenSCs) have great potential in regenerative medicine. MenSC has received increasing attention owing to its impressive therapeutic effects in both preclinical and clinical trials. However, the study of MenSC-derived small extracellular vesicles (EVs) is still in its initial stages, in contrast to some common MSC sources (e.g., bone marrow, umbilical cord, and adipose tissue). We describe the basic characteristics and biological functions of MenSC-derived small EVs. We also demonstrate the therapeutic potential of small EVs in fulminant hepatic failure, myocardial infarction, pulmonary fibrosis, prostate cancer, cutaneous wound, type-1 diabetes mellitus, aged fertility, and potential diseases. Subsequently, novel hotspots with respect to MenSC EV-based therapy are proposed to overcome current challenges. While complexities regarding the therapeutic potential of MenSC EVs continue to be unraveled, advances are rapidly emerging in both basic science and clinical medicine. MenSC EV-based treatment has great potential for treating a series of diseases as a novel therapeutic strategy in regenerative medicine.

Estrogen- and Progesterone (P4)-Mediated Epigenetic Modifications of Endometrial Stromal Cells (EnSCs) and/or Mesenchymal Stem/Stromal Cells (MSCs) in the Etiopathogenesis of Endometriosis

Endometriosis is a common chronic inflammatory condition in which endometrial tissue appears outside the uterine cavity. Because ectopic endometriosis cells express both estrogen and progesterone (P4) receptors, they grow and undergo cyclic proliferation and breakdown similar to the endometrium. This debilitating gynecological disease affects up to 15% of reproductive aged women. Despite many years of research, the etiopathogenesis of endometrial lesions remains unclear. Retrograde transport of the viable menstrual endometrial cells with retained ability for attachment within the pelvic cavity, proliferation, differentiation and subsequent invasion into the surrounding tissue constitutes the rationale for widely accepted implantation theory. Accordingly, the most abundant cells in the endometrium are endometrial stromal cells (EnSCs). These cells constitute a particular population with clonogenic activity that resembles properties of mesenchymal stem/stromal cells (MSCs). Thus, a significant role of stem cell-based dysfunction in formation of the initial endometrial lesions is suspected. There is increasing evidence that the role of epigenetic mechanisms and processes in endometriosis have been underestimated. The importance of excess estrogen exposure and P4 resistance in epigenetic homeostasis failure in the endometrial/endometriotic tissue are crucial. Epigenetic alterations regarding transcription factors of estrogen and P4 signaling pathways in MSCs are robust in endometriotic tissue. Thus, perspectives for the future may include MSCs and EnSCs as the targets of epigenetic therapies in the prevention and treatment of endometriosis. Here, we reviewed the current known changes in the epigenetic background of EnSCs and MSCs due to estrogen/P4 imbalances in the context of etiopathogenesis of endometriosis. Graphical Abstract.

IL-37 overexpression enhances the therapeutic effect of endometrial regenerative cells in concanavalin A-induced hepatitis

BACKGROUND AIMS

Mesenchymal stromal cells and immunosuppressive factor IL-37 can both suppress concanavalin A (Con A)-induced hepatitis in mice. Endometrial regenerative cells (ERCs), novel types of mesenchymal-like stromal cells, possess powerful immunomodulatory effects and are effective in treating various diseases. The aim of this study was to explore the effects of ERCs in suppressing Con A-induced hepatitis and determine whether IL-37 overexpression could enhance the therapeutic effect of ERCs in this process.

METHODS

ERCs were extracted from the menstrual blood of healthy female volunteer donors. The IL-37 gene was transferred into ERCs, and the expression of IL-37 in cells was detected by western blot and enzyme-linked immunosorbent assay. Hepatitis was induced by Con A in C57BL/6 mice that were randomly divided into groups treated with phosphate-buffered saline, ERCs, IL-37 or ERCs transfected with the IL-37 gene (IL-37-ERCs). Cell tracking, liver function, histopathological and immunohistological changes, immune cell proportions and levels of cytokines were measured 24 h after Con A administration.

RESULTS

Compared with ERC or IL-37 treatment, IL-37-ERCs further reduced levels of liver enzymes (alanine aminotransferase and aspartate aminotransferase) and improved histopathological changes in the liver. In addition, IL-37-ERC treatment further reduced the proportions of M1 macrophages and CD4+ T cells and increased the proportion of regulatory T cells. Moreover, IL-37-ERC treatment resulted in lower levels of IL-12 and interferon gamma, and higher level of transforming growth factor beta.

CONCLUSIONS

The results of this study suggest that ERCs can effectively alleviate Con A-induced hepatitis. Furthermore, IL-37 overexpression can significantly enhance the therapeutic efficacy of ERCs by augmenting the immunomodulatory and anti-inflammatory properties of ERCs. This study may provide a promising strategy for treatment of T-cell-dependent hepatitis.

IL-1β pre-stimulation enhances the therapeutic effects of endometrial regenerative cells on experimental colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing, and non-specific inflammatory bowel disease, and the current treatment strategies were mainly used to relieve symptoms or for maintenance. Endometrial regenerative cells (ERCs) are mesenchymal-like stromal cells and have been demonstrated to alleviate multiple immune-dysregulation diseases. Pro-inflammatory stimuli were reported to enhance the immunosuppressive functions of ERCs, but the mechanism underlined is not fully understood. Here, we have designed this study to investigate the therapeutic effects of IL-1β-primed ERCs in the attenuation of experimental colitis.

METHODS

BALB/c mice were given 3% dextran sodium sulfate (DSS) for 7 consecutive days and free tap water for 3 days sequentially to induce experimental colitis. PBS (200 μL), ERCs, and IL-1β-primed ERCs (10ng/mL, 48 h) were injected (1 million/mouse/day, i.v.) on day 2, 5, and 8, respectively. Colonic and splenic samples were harvested on day 10 after DSS induction.

RESULTS

It was found that IL-1β-primed ERC treatment markedly attenuated colonic damage, body weight loss, and colon length shortening in colitis mice. Compared with other treatments, cell populations of CD4⁺IL-4⁺Th2 cells, CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Tregs), and CD68⁺CD206⁺ macrophages in spleens were also significantly upregulated in the IL-1β-primed ERC-treated group (p < 0.05). In addition, lower expression of pro-inflammatory (IFN-γ, IL-17, TNF-α, and IL-6), but higher levels of anti-inflammatory cytokines (IL-4 and IL-10) were detected in colons in the IL-1β-primed ERC-treated group (p < 0.05 vs. other groups). Importantly, we also found that different generations of ERCs had an overall lower secretion of Dickkopf-1 (DKK1) by IL-1β pre-stimulation (p < 0.05) and a higher expression of β-catenin in colonic and splenic tissues after the administration of IL-1β-primed ERCs.

CONCLUSIONS

This study has demonstrated that IL-1β pre-stimulation effectively downregulated DKK1 expression in ERCs, which in turn promoted the wnt/β-catenin pathway activation in colonic and splenic tissues. Consequently, IL-1β-primed ERCs exhibited an enhanced therapeutic effect in the attenuation of DSS-induced colitis.

Regulation of Inflammatory Response by Transmembrane Adaptor Protein LST1

LST1 is a small adaptor protein expressed in leukocytes of myeloid lineage. Due to the binding to protein tyrosine phosphatases SHP1 and SHP2 it was thought to have negative regulatory function in leukocyte signaling. It was also shown to be involved in cytoskeleton regulation and generation of tunneling nanotubes. LST1 gene is located in MHCIII locus close to many immunologically relevant genes. In addition, its expression increases under inflammatory conditions such as viral infection, rheumatoid arthritis and inflammatory bowel disease and its deficiency was shown to result in slightly increased sensitivity to influenza infection in mice. However, little else is known about its role in the immune system homeostasis and immune response. Here we show that similar to humans, LST1 is expressed in mice in the cells of the myeloid lineage. In vivo, its deficiency results in alterations in multiple leukocyte subset abundance in steady state and under inflammatory conditions. Moreover, LST1-deficient mice show significant level of resistance to dextran sodium sulphate (DSS) induced acute colitis, a model of inflammatory bowel disease. These data demonstrate that LST1 regulates leukocyte abundance in lymphoid organs and inflammatory response in the gut.

Advances of Regulatory B Cells in Autoimmune Diseases

With the ability to induce T cell activation and elicit humoral responses, B cells are generally considered as effectors of the immune system. However, the emergence of regulatory B cells (Bregs) has given new insight into the role of B cells in immune responses. Bregs exhibit immunosuppressive functions via diverse mechanisms, including the secretion of anti-inflammatory cytokines and direct cell contact. The balance between Bregs and effector B cells is important for the immune tolerance. In this review, we focus on recent advances in the characteristics of Bregs and their functional roles in autoimmunity.

Therapeutic role of d-pinitol on experimental colitis via activating Nrf2/ARE and PPAR-γ/NF-κB signaling pathways

Ulcerative colitis is a recrudescent intestinal inflammation coupled with diarrhea, weight loss, pus, and blood stool, which seriously impacts the quality of patient life. d-Pinitol, which can be a food supplement isolated from the food plant-like soybeans, Ceratonia siliqua Linn and Bruguiera gymnorrhiza, has been proved to show anti-oxidative and anti-inflammatory effects. However, the potential mechanism of d-pinitol still remains ill-defined contemporarily. In the current study, the therapeutic effect and potential mechanisms of d-pinitol against colitis were investigated. Oxidative stress and inflammation of experimental colitis were caused by 3% DSS treatment once daily for 7 days. During DSS treatment, the mice of the positive drug group and three other groups were orally administered SASP or d-pinitol once daily. Clinical symptoms were analyzed, and macroscopic scores were calculated. The levels of oxidative and inflammatory cytokines were measured using assay kits and RT-PCR. Additionally, the protein expression of the Nrf2/ARE pathway and PPAR-γ was measured by Western blot. Results showed that d-pinitol enormously alleviated DSS-induced bodyweight loss, colon shortening, and histological injuries, achieving a therapeutic efficacy superior to SASP. Moreover, the oxidative stress and colonic inflammatory response were mitigated. d-pinitol not only significantly activated the Nrf2/ARE signaling pathway via facilitating the translocation of Nrf2 from sitoplazma to cytoblast, upregulating the protein expression levels of GCLC, GCLM, HO-1, and NQO1, but also improved the PPAR-γ level by binding to the active site of PPAR-γ, when suppressing NF-κB p65 and IκBα phosphorylation. In conclusion, d-pinitol exhibited a dramatic anti-colitis efficacy by activating the Nrf2/ARE pathway and PPAR-γ. Hence, d-pinitol may be a promising therapeutic drug against UC in the future.

Menstrual blood-derived stromal cells modulate functional properties of mouse and human macrophages

Menstrual blood-derived stromal cells (MenSCs) are emerging as a strong candidate for cell-based therapies due to their immunomodulatory properties. However, their direct impact on innate immune populations remains elusive. Since macrophages play a key role in the onset and development of inflammation, understanding MenSCs implication in the functional properties of these cells is required to refine their clinical effects during the treatment of inflammatory disorders. In this study, we assessed the effects that MenSCs had on the recruitment of macrophages and other innate immune cells in two mouse models of acute inflammation, a thioglycollate (TGC)-elicited peritonitis model and a monobacterial sepsis model. We found that, in the TGC model, MenSCs injection reduced the percentage of macrophages recruited to the peritoneum and promoted the generation of peritoneal immune cell aggregates. In the sepsis model, MenSCs exacerbated infection by diminishing the recruitment of macrophages and neutrophils to the site of infection and inducing defective bacterial clearance. Additional in vitro studies confirmed that co-culture with MenSCs impaired macrophage bactericidal properties, affecting bacterial killing and the production of reactive oxygen intermediates. Our findings suggest that MenSCs modulate the macrophage population and that this modulation must be taken into consideration when it comes to future clinical applications.

Endometrial and Menstrual Blood Mesenchymal Stem/Stromal Cells: Biological Properties and Clinical Application

A highly proliferative mesenchymal stem/stromal cell (MSC) population was recently discovered in the dynamic, cyclically regenerating human endometrium as clonogenic stromal cells that fulfilled the International Society for Cellular Therapy (ISCT) criteria. Specific surface markers enriching for clonogenic endometrial MSC (eMSC), CD140b and CD146 co-expression, and the single marker SUSD2, showed their perivascular identity in the endometrium, including the layer which sheds during menstruation. Indeed, cells with MSC properties have been identified in menstrual fluid and commonly termed menstrual blood stem/stromal cells (MenSC). MenSC are generally retrieved from menstrual fluid as plastic adherent cells, similar to bone marrow MSC (bmMSC). While eMSC and MenSC share several biological features with bmMSC, they also show some differences in immunophenotype, proliferation and differentiation capacities. Here we review the phenotype and functions of eMSC and MenSC, with a focus on recent studies. Similar to other MSC, eMSC and MenSC exert immunomodulatory and anti-inflammatory impacts on key cells of the innate and adaptive immune system. These include macrophages, T cells and NK cells, both in vitro and in small and large animal models. These properties suggest eMSC and MenSC as additional sources of MSC for cell therapies in regenerative medicine as well as immune-mediated disorders and inflammatory diseases. Their easy acquisition via an office-based biopsy or collected from menstrual effluent makes eMSC and MenSC attractive sources of MSC for clinical applications. In preparation for clinical translation, a serum-free culture protocol was established for eMSC which includes a small molecule TGFβ receptor inhibitor that prevents spontaneous differentiation, apoptosis, senescence, maintains the clonogenic SUSD2+ population and enhances their potency, suggesting potential for cell-therapies and regenerative medicine. However, standardization of MenSC isolation protocols and culture conditions are major issues requiring further research to maximize their potential for clinical application. Future research will also address crucial safety aspects of eMSC and MenSC to ensure these protocols produce cell products free from tumorigenicity and toxicity. Although a wealth of data on the biological properties of eMSC and MenSC has recently been published, it will be important to address their mechanism of action in preclinical models of human disease.

Stromal Cell-Derived Factor-1 Enhances the Therapeutic Effects of Human Endometrial Regenerative Cells in a Mouse Sepsis Model

Endometrial regenerative cells (ERCs) are mesenchymal-like stromal cells obtained from human menstrual blood, whose positive therapeutic effects have been validated in several experimental models. Stromal cell-derived factor-1 (SDF-1), the ligand for CXCR4, plays an important role in the migration of mesenchymal stromal cells. The purpose of this study was to investigate the role of the SDF-1/CXCR4 pathway in the therapeutic effects of ERCs in a mouse sepsis model. Through preexperiment and confirmation, wild-type C57BL/6 mice were intraperitoneally injected with 10 mg/kg lipopolysaccharide (LPS). The therapeutic effects of ERCs with different pretreatments were evaluated by assessing sepsis-related symptoms, detecting tissue damage and measuring levels of inflammatory and oxidative stress-related factors. The in vitro experiments demonstrated that there was a much higher CXCR4 expression on ERCs when they were cocultured with SDF-1. The ex vivo experiment results showed that SDF-1 expression significantly increased in mouse tissues. Further experiments also confirmed that, compared with the unmodified ERC treatment group, SDF-1 pretreatment significantly enhanced the therapeutic effects of ERCs on alleviating sepsis symptoms, ameliorating pathological changes, reducing Bax level, and increasing Bcl-2 and PCNA expressions in mouse liver tissues. Furthermore, it was also found that SDF-1-pretreated ERCs contributed to reducing the levels of proinflammatory cytokines (TNF-α, IL-1β) and increasing the levels of anti-inflammatory factors (IL-4, IL10) in mouse serum, liver, and lung. Moreover, SDF-1-pretreated ERCs could also significantly decrease the levels of iNOS and MDA and increase the expression of Nrf2, HO-1, and SOD in liver tissues. Taken together, these results indicate that SDF-1 pretreatment plays a key role in improving the therapeutic effects of ERCs in alleviating sepsis-related symptoms, reducing tissue damage, regulating inflammatory imbalance, and relieving oxidative stress in a mouse sepsis model, which provides more possibilities for the clinical application of ERCs in sepsis and relevant diseases.

Menstrual blood-derived stem cells: toward therapeutic mechanisms, novel strategies, and future perspectives in the treatment of diseases

Menstrual blood-derived stem cells (MenSCs) have great potential in the treatment of various diseases. As a novel type of mesenchymal stem cells (MSCs), MenSCs have attracted more interest due to their therapeutic effects in both animal models and clinical trials. Here, we described the differentiation, immunomodulation, paracrine, homing, and engraftment mechanisms of MenSCs. These include differentiation into targeting cells, immunomodulation with various immune cells, the paracrine effect on secreting cytokines, and homing and engraftment into injured sites. To better conduct MenSC-based therapy, some novel hotspots were proposed such as CRISPR (clustered regularly interspaced short palindromic repeats)/cas9-mediated gene modification, exosomes for cell-free therapy, single-cell RNA sequence for precision medicine, engineered MenSC-based therapy for the delivery platform, and stem cell niches for improving microenvironment. Subsequently, current challenges were elaborated on, with regard to age of donor, dose of MenSCs, transplantation route, and monitoring time. The management of clinical research with respect to MenSC-based therapy in diseases will become more normative and strict. Thus, a more comprehensive horizon should be considered that includes a combination of traditional solutions and novel strategies. In summary, MenSC-based treatment has a great potential in treating diseases through diverse strategies, and more therapeutic mechanisms and novel strategies need to be elucidated for future regenerative medicine and clinical applications.

Mesenchymal stem cells for the treatment of ulcerative colitis: a systematic review and meta-analysis of experimental and clinical studies

OBJECTIVE

To explore the promising use of mesenchymal stem cells (MSCs) for ulcerative colitis (UC).

METHODS

Studies reporting MSC treatment on UC were searched on five databases. Methodological quality was assessed based on the SYRCLE's Risk of Bias (RoB) tool and MINORS tool. Data analysis was conducted using Engauge Digitizer 10.8 and Stata 14.0.

RESULTS

A total of 15 studies met the inclusion criteria including 8 animal (n = 132) and 7 human (n = 216) trials. In animal studies, mice treated with MSCs had significantly lower disease activity index (DAI) than that in the control group: the 1st day (standardized mean difference (SMD) - 0.753, p = 0.027), the 3rd day (SMD - 1.634, p = 0.000), the 5th day (SMD - 2.124, p = 0.000), the 7th day (SMD - 5.327, p = 0.000), the 9th day (SMD - 2.979, p = 0.000), and the 14th day (SMD - 5.032, p = 0.000). Lower histopathological score (HS) (SMD - 5.15, p < 0.05) and longer colon length (SMD 2.147, p = 0.001) in mice treated with MSCs were also indicated. The main outcome in clinical trials showed, compared with control group, healing rate of patients accompanied by MSC therapy elevated obviously: MSCs vs 5-aminosalicylic acids (5-ASA) (RR = 2.317, p = 0.000) and MSCs + 5-ASA vs placebo + 5-ASA (RR = 5.118). The analytical data in 4 trials conducted with single-arm studies also demonstrated increased healing rate (0.787) after MSC treatment (p = 0.000).

CONCLUSION

Our meta-analysis results supported that MSCs could be an underlying method of treating UC.

SDF-1/CXCR4 axis enhances the immunomodulation of human endometrial regenerative cells in alleviating experimental colitis

Endometrial regenerative cells (ERCs) are a new type of mesenchymal-like stromal cells, and their therapeutic potential has been tested in a variety of disease models. SDF-1/CXCR4 axis plays a chemotaxis role in stem/stromal cell migration. The aim of the present study was to investigate the role of SDF-1/CXCR4 axis in the immunomodulation of ERCs on the experimental colitis. The immunomodulation of ERCs in the presence or absence of pretreatment of SDF-1 or AMD3100 was examined in both in vitro cell culture system and dextran sulphate sodium-induced colitis in mice. The results showed that SDF-1 increased the expression of CXCR4 on the surface of ERCs. As compared with normal ERCs, the SDF-1-treated, CXCR4 high-expressing ERCs more significantly suppressed dendritic cell population as well as stimulated both type 2 macrophages and regulatory T cells in vitro and in vivo. Meanwhile, SDF-1-pretreated ERCs increased the generation of anti-inflammatory factors (e.g., IL-4, IL-10) and decreased the pro-inflammatory factors (e.g., IL-6, TNF-α). In addition, SDF-1-pretreated CM-Dil-labeled ERCs were found to engraft to injured colon. Our results may suggest that an SDF-1-induced high level of CXCR4 expression enhances the immunomodulation of ERCs in alleviating experimental colitis in mice.

Stem cells on regenerative and reproductive science in domestic animals

Stem cells are undifferentiated and self-renewable cells that present new possibilities for both regenerative medicine and the understanding of early mammalian development. Adult multipotent stem cells are already widely used worldwide in human and veterinary medicine, and their therapeutic signalling, particularly with respect to immunomodulation, and their trophic properties have been intensively studied. The derivation of embryonic stem cells (ESCs) from domestic species, however, has been challenging, and the poor results do not reflect the successes obtained in mouse and human experiments. More recently, the generation of induced pluripotent stem cells (iPSCs) via the forced expression of specific transcription factors has been demonstrated in domestic species and has introduced new potentials in regenerative medicine and reproductive science based upon the ability of these cells to differentiate into a variety of cells types in vitro. For example, iPSCs have been differentiated into primordial germ-like cells (PGC-like cells, PGCLs) and functional gametes in mice. The possibility of using iPSCs from domestic species for this purpose would contribute significantly to reproductive technologies, offering unprecedented opportunities to restore fertility, to preserve endangered species and to generate transgenic animals for biomedical applications. Therefore, this review aims to provide an updated overview of adult multipotent stem cells and to discuss new possibilities introduced by the generation of iPSCs in domestic animals, highlighting the possibility of generating gametes in vitro via PGCL induction.