A20 plays a critical role in the immunoregulatory function of mesenchymal stem cells

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

MEG3 alleviates ankylosing spondylitis by suppressing osteogenic differentiation of mesenchymal stem cells through regulating microRNA-125a-5p-mediated TNFAIP3

Osteoblasts are important regulators of bone formation, but their roles in ankylosing spondylitis (AS) remain unclear. This study aims to explore the role of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) MEG3 in AS. Serum from AS patients as well as AS mesenchymal stem cells (ASMSCs) and healthy donors mesenchymal stem cells (HDMSCs) was collected. Accordingly, poorly expressed MEG3 and TNF alpha induced protein 3 (TNFAIP3) as well as overexpressed microRNA-125a-5p (miR-125a-5p) were noted in the serum of AS patients and in ASMSCs during the osteogenic induction process. Meanwhile, the interaction among MEG3, miR-125a-5p, and TNFAIP3 was determined and their effect on osteoblast activity was examined in vitro and in vivo. Overexpression of MEG3 and TNFAIP3 or inhibition of miR-125a-5p was found to inactivate the Wnt/β-catenin pathway, thus suppressing osteogenic differentiation of MSCs. MEG3 competitively bound to miR-125a-5p to increase TNFAIP3 expression, thereby inactivating the Wnt/β-catenin pathway and repressing the osteogenic differentiation of MSCs. In proteoglycan (PG)-induced AS mouse models, MEG3 also reduced osteogenic activity of MSCs to inhibit AS progression through the miR-125a-5p/TNFAIP3/Wnt/β-catenin axis. Therefore, up-regulation of MEG3 or depletion of miR-125a-5p holds potential of alleviating AS, which sheds light on a new therapeutic strategy for AS treatment.

TNFAIP3 promotes ALDH-positive breast cancer stem cells through FGFR1/MEK/ERK pathway

Breast cancer stem cells (BCSCs) are a tiny population of self-renewing cells that may contribute to cancer initiation, progression, and resistance to therapy in patients. In our prior study, we found that tumor necrosis factor alpha-induced protein 3 (TNFAIP3) is necessary for fibroblast growth factors receptor 1 (FGFR1) signaling-promoted tumor growth and progression in breast cancer (BC). This study aims to investigate the involvement of TNFAIP3 in regulating BCSCs. In this work, we showed that ALDH-positive BCSCs were increased by activating the FGFR1-MEK-ERK pathway, meanwhile utilizing FGFR1 inhibitor, MEK inhibitor, or ERK inhibitor reversed the phenomenon in BC cells. Moreover, ALDH-positive BCSCs were decreased in TNFAIP3-knockout or TNFAIP3-depressing cells. In vivo analysis displayed that TNFAIP3-silenced MDA-MB-231 xenografts developed smaller tumors and ALDH immunostaining levels were significantly lower in TNFAIP3-depressing or TNFAIP3-knockout tumor tissues. Besides, our results also revealed that TNFAIP3 influences the transcription stemness factors gene expression. Taken together, TNFAIP3 could be a potential regulator in FGFR1-MEK-ERK-promoted ALDH-positive BCSCs.

Cell-based therapies for rheumatoid arthritis: opportunities and challenges

Rheumatoid arthritis (RA) is the most common immune-mediated inflammatory disease characterized by chronic synovitis that hardly resolves spontaneously. The current treatment of RA consists of nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, conventional disease-modifying antirheumatic drugs (cDMARDs), biologic and targeted synthetic DMARDs. Although the treat-to-target strategy has been intensively applied in the past decade, clinical unmet needs still exist since a substantial proportion of patients are refractory or even develop severe adverse effects to current therapies. In recent years, with the deeper understanding of immunopathogenesis of the disease, cell-based therapies have exhibited effective and promising interventions to RA. Several cell-based therapies, such as mesenchymal stem cells (MSC), adoptive transfer of regulatory T cells (Treg), and chimeric antigen receptor (CAR)-T cell therapy as well as their beneficial effects have been documented and verified so far. In this review, we summarize the current evidence and discuss the prospect as well as challenges for these three types of cellular therapies in RA.

Recombinant Porphyromonas gingivalis W83 FimA alters immune response and metabolic gene expression in oral squamous carcinoma cells

Objectives

The Gram‐negative anaerobic rod Porphyromonas gingivalis (P. gingivalis) is regarded as a keystone pathogen in periodontitis and expresses a multitude of virulence factors iincluding fimbriae that are enabling adherence to and invasion in cells and tissues. The progression of periodontitis is a consequence of the interaction between the host immune response and periodontal pathogens. The aim of this study was to investigate the genome‐wide impact of recombinant fimbrial protein FimA from P. gingivalis W83 on the gene expression of oral squamous carcinoma cells by transcriptome analysis.

Materials and Methods

Human squamous cell carcinoma cells (SCC‐25) were stimulated for 4 and 24 h with recombinant FimA. RNA sequencing was performed and differential gene expression and enrichment were analyzed using gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and REACTOME. The results of transcriptome analysis were validated using quantitative real‐time polymerase chain reaction (PCR) with selected genes.

Results

Differential gene expression after 4 and 24 h revealed upregulation of 464 (4 h) and 179 genes (24 h) and downregulation of 69 (4 h) and 312 (24 h) genes. GO, KEGG, and REACTONE enrichment analysis identified a strong immunologic transcriptomic response signature after 4 h. After 24 h, mainly those genes were regulated, which belonged to cell metabolic pathways and replication. Real‐time PCR of selected genes belonging to immune response and signaling demonstrated strong upregulation of CCL20, TNFAIP6, CXCL8, TNFAIP3, and NFkBIA after both stimulation times.

Conclusions

These data shed light on the RNA transcriptome of human oral squamous carcinoma epithelial cells following stimulation with P. gingivalis FimA and identify a strong immunological gene expression response to this virulence factor. The data provide a base for future studies of molecular and cellular interactions between P. gingivalis and oral epithelium to elucidate basic mechanisms that may provide new prospects for periodontitis therapy and give new insights into the development and possible treatments of cancer.

Porphyromonas gingivalis W83 Membrane Components Induce Distinct Profiles of Metabolic Genes in Oral Squamous Carcinoma Cells

Periodontitis, a chronic inflammatory disease is caused by a bacterial biofilm, affecting all periodontal tissues and structures. This chronic disease seems to be associated with cancer since, in general, inflammation intensifies the risk for carcinoma development and progression. Interactions between periodontal pathogens and the host immune response induce the onset of periodontitis and are responsible for its progression, among them Porphyromonas gingivalis (P. gingivalis), a Gram-negative anaerobic rod, capable of expressing a variety of virulence factors that is considered a keystone pathogen in periodontal biofilms. The aim of this study was to investigate the genome-wide impact of P. gingivalis W83 membranes on RNA expression of oral squamous carcinoma cells by transcriptome analysis. Human squamous cell carcinoma cells (SCC-25) were infected for 4 and 24 h with extracts from P. gingivalis W83 membrane, harvested, and RNA was extracted. RNA sequencing was performed, and differential gene expression and enrichment were analyzed using GO, KEGG, and REACTOME. The results of transcriptome analysis were validated using quantitative real-time PCR with selected genes. Differential gene expression analysis resulted in the upregulation of 15 genes and downregulation of 1 gene after 4 h. After 24 h, 61 genes were upregulated and 278 downregulated. GO, KEGG, and REACTONE enrichment analysis revealed a strong metabolic transcriptomic response signature, demonstrating altered gene expressions after 4 h and 24 h that mainly belong to cell metabolic pathways and replication. Real-time PCR of selected genes belonging to immune response, signaling, and metabolism revealed upregulated expression of CCL20, CXCL8, NFkBIA, TNFAIP3, TRAF5, CYP1A1, and NOD2. This work sheds light on the RNA transcriptome of human oral squamous carcinoma cells following stimulation with P. gingivalis membranes and identifies a strong metabolic gene expression response to this periodontal pathogen. The data provide a base for future studies of molecular and cellular interactions between P. gingivalis and oral epithelium to elucidate the basic mechanisms of periodontitis and the development of cancer.

Regulatory Effect of Mesenchymal Stem Cells on T Cell Phenotypes in Autoimmune Diseases

Research on mesenchymal stem cells (MSCs) starts from the earliest assumption that cells derived from the bone marrow have the ability to repair tissues. Several scientists have since documented the crucial role of bone marrow-derived MSCs (BM-MSCs) in processes such as embryonic bone and cartilage formation, adult fracture and tissue repair, and immunomodulatory activities in therapeutic applications. In addition to BM-MSCs, several sources of MSCs have been reported to possess tissue repair and immunoregulatory abilities, making them potential treatment options for many diseases. Therefore, the therapeutic potential of MSCs in various diseases including autoimmune conditions has been explored. In addition to an imbalance of T cell subsets in most patients with autoimmune diseases, they also exhibit complex disease manifestations, overlapping symptoms among diseases, and difficult treatment. MSCs can regulate T cell subsets to restore their immune homeostasis toward disease resolution in autoimmune conditions. This review summarizes the role of MSCs in relieving autoimmune diseases via the regulation of T cell phenotypes.

Human multipotent mesenchymal stromal cells cytokine priming promotes RAB27B-regulated secretion of small extracellular vesicles with immunomodulatory cargo

Background

The paracrine effects of multipotent mesenchymal stromal cells (MSCs) are mediated by their secretome composed by soluble factors (i.e., cytokines, growth factors, hormones) and extracellular vesicles (EVs). EVs promote intercellular communication, and the EV cargoes [e.g., proteins, soluble factors, microRNAs (miRNAs), messenger RNA (mRNA), DNA] reflect the molecular and functional characteristics of their parental cells. MSC-derived EVs (MSC-EVs) are currently evaluated as subcellular therapeutics. A key function of the MSC secretome is its ability to promote immune tolerance (i.e., immunopotency), a property that is enhanced by priming approaches (e.g., cytokines, hypoxia, chemicals) and inversely correlates with the age of the MSC donors. We evaluated mechanisms underlying MSC vesiculation and the effects of inflammation and aging on this process.

Methods

We evaluated the effects of interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) on human adipose-derived MSC: (a) vesiculation (custom RT² Profiler PCR Array), (b) EV profiles (Nanoparticle Tracking Analysis and Nanoparticle Flow Cytometry), (c) EV cargo (proteomic analysis and Western blot analysis), and (d) immunopotency (standard MSC:CD4 T cell proliferation inhibition assay). We confirmed the role of RAB27B on MSC vesiculation (RAB27B siRNA) and assessed its differential contribution to vesiculation in adult and pediatric MSCs (qPCR).

Results

Cytokine priming upregulated RAB27B in adipose-derived MSCs increasing their secretion of exosome-like small EVs (sEVs; < 200 nm) containing two key mediators of immunopotency: A20 and TSG-6. These EVs inhibited T cell proliferation in a dose-dependent manner. RAB27B siRNA inhibited MSC vesiculation. Adipose-derived MSCs isolated from pediatric donors exhibited higher RAB27B expression and secreted more sEVs than adult MSCs.

Conclusions

Cytokine priming is a useful strategy to harvest anti-inflammatory MSC-sEVs for clinical applications. Of relevance, donor age should be considered in the selection of MSC-sEVs for clinical applications.

miR-129-5p Regulates the Immunomodulatory Functions of Adipose-Derived Stem Cells via Targeting Stat1 Signaling

Adipose-derived stem cells (ASCs) have become one of the most promising stem cell populations for cell-based therapies in regenerative medicine and for autoimmune disorders owing to their multilineage differentiation and immunomodulatory capacities, respectively. One advantage of ASC-based therapy lies in their immunosuppressive potential. However, how to get ASCs to provide consistent immunosuppression remains unclear. In the current study, we found that miR-129-5p was induced in ASCs treated with inflammatory factors. ASCs with miR-129-5p knockdown exhibited enhanced immunosuppressive capacity, as evidenced by reduced expression of proinflammatory factors, with concurrent increased expression of inducible nitric oxide synthases (iNOS) and nitric oxide (NO) production. These cells also had an increased capacity to inhibit T cell proliferation in vitro. ASCs with miR-129-5p knockdown alleviated inflammatory bowel diseases and promoted tumor growth in vivo. Consistently, ASCs that overexpressed miR-129-5p exhibited reduced iNOS expression. Furthermore, we show that miR-129-5p knockdown in ASCs results in hyperphosphorylation of signal transducer and activator of transcription 1 (Stat1). When fludarabine, an inhibitor of Stat1 activation, was added to ASCs with miR-129-5p knockdown, iNOS mRNA and protein levels were significantly reduced. Collectively, these results reveal a new role for miR-129-5p in regulating the immunomodulatory activities of ASCs by targeting Stat1 activation. These novel insights into the mechanisms of ASC immunoregulation may lead to the consistent production of ASCs with strong immunosuppressive functions and thus better clinical utility of these cells.

Mysm1 epigenetically regulates the immunomodulatory function of adipose-derived stem cells in part by targeting miR-150

Adipose‐derived stem cells (ASCs) are highly attractive for cell‐based therapies in tissue repair and regeneration because they have multilineage differentiation capacity and are immunosuppressive. However, the detailed epigenetic mechanisms of their immunoregulatory capacity are not fully defined. In this study, we found that Mysm1 was induced in ASCs treated with inflammatory cytokines. Adipose‐derived stem cells with Mysm1 knockdown exhibited attenuated immunosuppressive capacity, evidenced by less inhibition of T cell proliferation, more pro‐inflammatory factor secretion and less nitric oxide (NO) production in vitro. Mysm1‐deficient ASCs exacerbated inflammatory bowel diseases but inhibited tumour growth in vivo. Mysm1‐deficient ASCs also showed depressed miR‐150 expression. When transduced with Mysm1 overexpression lentivirus, ASCs exhibited enhanced miR‐150 expression. Furthermore, Mysm1‐deficient cells transduced with lentivirus containing miR‐150 mimics produced less pro‐inflammatory factors and more NO. Our study reveals a new role of Mysm1 in regulating the immunomodulatory activities of ASCs by targeting miR‐150. These novel insights into the mechanisms through which ASCs regulate immune reactions may lead to better clinical utility of these cells.

Biofilm-induced profiles of immune response gene expression by oral epithelial cells

This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge. We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria. Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes. Biofilm challenged stimulated significant elevations compared to planktonic bacteria for IL32, IL8, CD44, B2M, TGFBI, NFKBIA, IL1B, CD59, IL1A, CCL20 representing the top 10 signals comprising 55% of the overall signal for the epithelial cell responses. Levels of PLAU, CD9, IFITM1, PLAUR, CD24, TNFSF10, and IL1RN were all elevated by each of the planktonic bacterial challenge vs the biofilm responses. While the biofilms up-regulated 123/579 genes (>2-fold), fewer genes were increased by the planktonic species (36 [S gordonii], 30 [F nucleatum], 44 [P gingivalis]). A wide array of immune genes were regulated by oral bacterial challenge of epithelial cells that would be linked to the local activity of innate and adaptive immune response components in the gingival tissues. Incorporating bacterial species into a structured biofilm dramatically altered the number and level of genes expressed. Additionally, a specific set of genes were significantly decreased with the multispecies biofilms suggesting that some epithelial cell biologic pathways are down-regulated when in contact with this type of pathogenic biofilm.

Mesenchymal stem cells in suppression or progression of hematologic malignancy: current status and challenges

Mesenchymal stem cells (MSCs) are known for being multi-potent. However, they also possess anticancer properties, which has prompted efforts to adapt MSCs for anticancer therapies. However, MSCs have also been widely implicated in pathways that contribute to tumor growth. Numerous studies have been conducted to adapt MSCs for further clinical use; however, the results have been inconclusive, possibly due to the heterogeneity of MSC populations. Moreover, the conflicting roles of MSCs in tumor inhibition and tumor growth impede their adaptation for anticancer therapies. Antitumorigenic and protumorigenic properties of MSCs in hematologic malignancies are not as well established as they are for solid malignancies, and data comparing them are still limited. Herein the effect of MSCs on hematologic malignancies, such as leukemia and lymphoma, their mechanisms, sources of MSCs, and their effects on different types of cancer, have been discussed. This review describes how MSCs preserve both antitumorigenic and protumorigenic effects, as they tend to not only inhibit tumor growth by suppressing tumor cell proliferation but also promote tumor growth by suppressing tumor cell apoptosis. Thus clinical studies trying to adapt MSCs for anticancer therapies should consider that MSCs could actually promote hematologic cancer progression. It is necessary to take extreme care while developing MSC-based cell therapies in order to boost anticancer properties while eliminating tumor-favoring effects. This review emphasizes that research on the therapeutic applications of MSCs must consider that they exert both antitumorigenic and protumorigenic effects on hematologic malignancies.

Decreased expression of A20 is associated with ocular Behcet's disease (BD) but not with Vogt-Koyanagi-Harada (VKH) disease

PURPOSE

A20 is a ubiquitously expressed and inducible cytosolic protein, which plays an important role in the negative regulation of inflammation and immunity. In this study, we investigated the role of A20 in Behcet's disease (BD) and Vogt-Koyanagi-Harada (VKH) disease.

METHODS

The levels of A20 in peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) were detected in BD patients with active and inactive uveitis, VKH patients with active and inactive uveitis, and normal subjects, respectively, by real-time PCR. The effect of A20 silencing was performed by transduction of DCs with adenovirus containing an A20 shRNA vector. The effect of A20 silencing on the maturation of DCs was measured by flow cytometry. The effect of A20 silencing of DCs on cytokine production by DCs and CD4⁺ T cells was analysed by ELISA. The phosphorylation levels of JNK, p38 and ERK1/2 were detected by flow cytometry.

RESULTS

The expression of A20 was markedly decreased in PBMCs and DCs obtained from BD patients with active uveitis, but not in patients with VKH disease as compared with normal controls. Silencing of A20 significantly increased the levels of interleukin (IL)-1β and IL-6 and suppressed the expression of the anti-inflammatory cytokines IL-10 and IL-27. Downregulation of A20 also led to an increase in IL-17 production by CD4⁺ T cells. However, downregulation of A20 in DCs did not have an effect on cell surface markers such as CD40, CD80, CD83, CD86 and HLA-DR. Silencing of A20 caused an increased expression of phospho-JNK and phospho-MAPK p38 but not phospho-ERK1/2.

CONCLUSIONS

This study showed that the expression of A20 was decreased in BD patients with active uveitis but not in VKH disease. Decreased expression of A20 may lead to an enhanced activation of proinflammatory Th17 cells, causing a reactivation of BD.

Loss of A20 in BM-MSCs regulates the Th17/Treg balance in Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) are multi-potent cells that are self-renewable and possess the potential to differentiate into multiple lineages. Several studies demonstrated that MSCs could regulate a Th17/Treg balance and could be a potential therapeutic target for Rheumatoid Arthritis (RA). A20 is highly expressed in many cell types after the stimulation of TNF-α, where it may inhibit pro-inflammatory cytokine secretion. However, the expression of A20 in BM-MSCs in RA is not fully understood. In our study, we found that A20 was decreased in RA patients’ bone marrow MSCs (BM-MSCs), and with more IL-6 secretion, the balance of Th17/Treg was broken. In CIA mice, we found a moderate A20 decrease in mice MSCs as compared with those of control group in mRNA and protein levels. However, the IL-6 expression was increased. After umbilical cord MSCs treatment, A20 and IL-6 expressions were equal to the control group. Thus, our study indicates that loss of A20 in MSCs regulates the Th17/Treg balance in RA and the regulatory role of A20 in pro-inflammatory IL-6 production could be a potential target for the transfer of MSCs in RA adoptive therapy.

[Mesenchymal stem/stroma cells : Therapeutic potential in the treatment of autoimmune diseases]

Mesenchymal stem and stromal cells (MSC) are propagated for the treatment of autoimmune and autoinflammatory processes. These cells can be relatively easily obtained from various tissues. The MSC feature anti-inflammatory and immunosuppressive properties in vitro as well as in animal models. Initial reports on the clinical application of MSC for various diseases are available, some with promising results and so far no reported toxicity; however, data from phase III studies are still lacking and crucial questions are still unanswered. The MSC preparations used are heterogeneous and also differ depending on the source and it is unclear whether autologous (own) or allogeneic (foreign) MSC are more suitable for therapeutic use. Long-term consequences, such as possible malignant transformation and possible endogenous tumor growth stimulation cannot be completely excluded. Ultimately, these questions can only be answered through randomized controlled trials for defined clinical indications with defined MSC.