IL-17 and FGF signaling involved in mouse mesenchymal stem cell proliferation

The Influence of Intervertebral Disc Microenvironment on the Biological Behavior of Engrafted Mesenchymal Stem Cells

Intervertebral disc degeneration is the main cause of low back pain. Traditional treatment methods cannot repair degenerated intervertebral disc tissue. The emergence of stem cell therapy makes it possible to regenerate and repair degenerated intervertebral disc tissue. At present, mesenchymal stem cells are the most studied, and different types of mesenchymal stem cells have their own characteristics. However, due to the harsh and complex internal microenvironment of the intervertebral disc, it will affect the biological behaviors of the implanted mesenchymal stem cells, such as viability, proliferation, migration, and chondrogenic differentiation, thereby affecting the therapeutic effect. This review is aimed at summarizing the influence of each intervertebral disc microenvironmental factor on the biological behavior of mesenchymal stem cells, so as to provide new ideas for using tissue engineering technology to assist stem cells to overcome the influence of the microenvironment in the future.

Single-cell transcriptome atlas of human mesenchymal stem cells exploring cellular heterogeneity

BACKGROUND

The heterogeneity of mesenchymal stem cells (MSCs) is poorly understood, thus limiting clinical application and basic research reproducibility. Advanced single-cell RNA sequencing (scRNA-seq) is a robust tool used to analyse for dissecting cellular heterogeneity. However, the comprehensive single-cell atlas for human MSCs has not been achieved.

METHODS

This study used massive parallel multiplexing scRNA-seq to construct an atlas of > 130 000 single-MSC transcriptomes across multiple tissues and donors to assess their heterogeneity. The most widely clinically utilised tissue resources for MSCs were collected, including normal bone marrow (n = 3), adipose (n = 3), umbilical cord (n = 2), and dermis (n = 3).

RESULTS

Seven tissue-specific and five conserved MSC subpopulations with distinct gene-expression signatures were identified from multiple tissue origins based on the high-quality data, which has not been achieved previously. This study showed that extracellular matrix (ECM) highly contributes to MSC heterogeneity. Notably, tissue-specific MSC subpopulations were substantially heterogeneous on ECM-associated immune regulation, antigen processing/presentation, and senescence, thus promoting inter-donor and intra-tissue heterogeneity. The variable dynamics of ECM-associated genes had discrete trajectory patterns across multiple tissues. Additionally, the conserved and tissue-specific transcriptomic-regulons and protein-protein interactions were identified, potentially representing common or tissue-specific MSC functional roles. Furthermore, the umbilical-cord-specific subpopulation possessed advantages in immunosuppressive properties.

CONCLUSION

In summary, this work provides timely and great insights into MSC heterogeneity at multiple levels. This MSC atlas taxonomy also provides a comprehensive understanding of cellular heterogeneity, thus revealing the potential improvements in MSC-based therapeutic efficacy.

Regulation of the mesenchymal stem cell fate by interleukin-17: Implications in osteogenic differentiation

Bone regeneration is a tightly regulated process that ensures proper repair and functionality after injury. The delicate balance between bone formation and resorption is governed by cytokines and signaling molecules released during the inflammatory response. Interleukin (IL)-17A, produced in the early phase of inflammation, influences the fate of osteoprogenitors. Due to their inherent capacity to differentiate into osteoblasts, mesenchymal stem/stromal cells (MSCs) contribute to bone healing and regeneration. This review presents an overview of IL-17A signaling and the leading cellular and molecular mechanisms by which it regulates the osteogenic differentiation of MSCs. The main findings demonstrating IL-17A’s influence on osteoblastogenesis are described. To this end, divergent information exists about the capacity of IL-17A to regulate MSCs’ osteogenic fate, depending on the tissue context and target cell type, along with contradictory findings in the same cell types. Therefore, we summarize the data showing both the pro-osteogenic and anti-osteogenic roles of IL-17, which may help in the understanding of IL-17A function in bone repair and regeneration.

Dynamic stromal cellular reaction throughout human colorectal adenoma-carcinoma sequence: A role of TH17/IL-17A

BACKGROUND

Accumulating data suggest that the tumour stroma rapidly undergoes dynamic mechanical and cellular changes by which creates a supportive milieu to promote disease progression and metastasis. Cytokines are reported to play a key role in the modulation of tumour stromal response.

METHODS

The activation of TH17/interleukin (IL)-17A network in association with tumour stromal proliferative and cellular response in samples from 50 patients with colorectal adenoma, 45 with colorectal cancer (CRCs) were elucidated with quantitative real-time PCR (q-PCR), immunohistochemistry and double immunofluorescence.

RESULTS

q-PCR results showed that retinoic acid-receptor-related orphan receptor-C, a critical transcriptional factor for TH17 cell differentiation, was significantly increased at the adenoma stage and slightly decreased at the CRC stage, but was still higher than that at normal controls. The level of TH17 signature cytokine IL-17A was shown in an increasing gradient throughout the adenoma-carcinoma sequence. Immunohistochemistry revealed an activated proliferative rate evaluated by Ki67 and population expansion of myofibroblasts in the adenoma/CRC stroma. Notably, densities of IL-17A-expressing cells were associated with populations of Ki67-positive cells and myofibroblasts in the adenoma/CRC stroma. Finally, CD146-positive stromal cells are an important participator for stroma remodelling, double immunofluorescence image demonstrated that IL-17 receptor C, one of the key elements for IL-17 receptor complex, was highly expressed in CD146-positive adenoma/CRC stromal cells.

CONCLUSIONS

An activated TH17/IL-17A network in the tumour microenvironment is significantly associated with dynamic stromal cellular response throughout the adenoma-carcinoma sequence, which might provide a supportive environment for the initiation and progression of CRC.

Modulating stemness of mesenchymal stem cells from exfoliated deciduous and permanent teeth by IL-17 and bFGF

Mesenchymal stem cells (MSCs) have been identified within dental pulp tissues of exfoliated deciduous (SHEDs) and permanent (DPSCs) teeth. Although differences in their proliferative and differentiation properties were revealed, variability in SHEDs and DPSCs responsiveness to growth factors and cytokines have not been studied before. Here, we investigated the influence of interleukin-17 (IL-17) and basic fibroblast growth factor (bFGF) on stemness features of SHEDs and DPSCs by analyzing their proliferation, clonogenicity, cell cycle progression, pluripotency markers expression and differentiation after 7-day treatment. Results indicated that IL-17 and bFGF differently affected SHEDs and DPSCs proliferation and clonogenicity, since bFGF increased proliferative and clonogenic potential of both cell types, while IL-17 similarly affected SHEDs, exerting no effects on adult counterparts DPSCs. In addition, both factors stimulated NANOG, OCT4, and SOX2 pluripotency markers expression in SHEDs and DPSCs showing diverse intracellular expression patterns dependent on MSCs type. As for the differentiation capacity, both factors displayed comparable effects on SHEDs and DPSCs, including stimulatory effect of IL-17 on early osteogenesis in contrast to the strong inhibitory effect showed for bFGF, while having no impact on SHEDs and DPSCs chondrogenesis. Moreover, bFGF combined with IL-17 reduced CD90 and stimulated CD73 expression on both types of MSCs, whereas each factor induced IL-6 expression indicating its' role in IL-17/bFGF-modulated properties of SHEDs and DPSCs. All these data demonstrated that dental pulp MSCs from primary and permanent teeth exert intrinsic features, providing novel evidence on how IL-17 and bFGF affect stem cell properties important for regeneration of dental pulp at different ages.

Synthetic polymers as xeno-free materials for stabilizing basic fibroblast growth factor in human mesenchymal stem cell cultures

Series of sulfonated polymers were evaluated as additives in cell culture media. Some of the compounds, such as sulfated polyvinyl alcohol (PVA), prevented denaturation and loss of basic fibroblast growth factor during cell culture and enhanced human mesenchymal stem cell proliferation. These compounds are xeno-free alternatives of heparin, an animal-derived sulfated saccharide, often used as an additive. To the best our knowledge, this study is the first to show that chemically defined synthetic chemicals, such as sulfated polyvinyl alcohol, can be used for this purpose.

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Basic fibroblast growth factor in stem cell culture medium decreased during culture.

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Basic fibroblast growth factor concentration was correlated with culture results.

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Sulfated materials were evaluated to protect basic fibroblast growth factor.

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Four materials showed protective effect and hence activated cell proliferation.

Inflammatory niche: Mesenchymal stromal cell priming by soluble mediators

Mesenchymal stromal/stem cells (MSCs) are adult stem cells of stromal origin that possess self-renewal capacity and the ability to differentiate into multiple mesodermal cell lineages. They play a critical role in tissue homeostasis and wound healing, as well as in regulating the inflammatory microenvironment through interactions with immune cells. Hence, MSCs have garnered great attention as promising candidates for tissue regeneration and cell therapy. Because the inflammatory niche plays a key role in triggering the reparative and immunomodulatory functions of MSCs, priming of MSCs with bioactive molecules has been proposed as a way to foster the therapeutic potential of these cells. In this paper, we review how soluble mediators of the inflammatory niche (cytokines and alarmins) influence the regenerative and immunomodulatory capacity of MSCs, highlighting the major advantages and concerns regarding the therapeutic potential of these inflammatory primed MSCs. The data summarized in this review may provide a significant starting point for future research on priming MSCs and establishing standardized methods for the application of preconditioned MSCs in cell therapy.

Priming approaches to improve the efficacy of mesenchymal stromal cell-based therapies

Multipotent mesenchymal stromal cells (MSC) have been widely explored for cell-based therapy of immune-mediated, inflammatory, and degenerative diseases, due to their immunosuppressive, immunomodulatory, and regenerative potentials. Preclinical studies and clinical trials have demonstrated promising therapeutic results although these have been somewhat limited. Aspects such as low in vivo MSC survival in inhospitable disease microenvironments, requirements for ex vivo cell overexpansion prior to infusions, intrinsic differences between MSC and different sources and donors, variability of culturing protocols, and potency assays to evaluate MSC products have been described as limitations in the field. In recent years, priming approaches to empower MSC have been investigated, thereby generating cellular products with improved potential for different clinical applications. Herein, we review the current priming approaches that aim to increase MSC therapeutic efficacy. Priming with cytokines and growth factors, hypoxia, pharmacological drugs, biomaterials, and different culture conditions, as well as other diverse molecules, are revised from current and future perspectives.

Alteration of specific cytokine expression patterns in patients with breast cancer

Systemic inflammation has been associated with aggressive tumor growth, invasion, and metastasis. Here we performed a comprehensive analysis of 26 kinds of inflammatory cytokine expression patterns among 185 patients with breast cancer and 54 healthy volunteers followed by chemometric analysis. We identified the specific cytokine expression patterns of breast cancer patients compared to healthy volunteers with (1) VEGF, IL-9, GM-CSF, IL-13, IL-4, and IFNγ, (2) IL-8, IL-10, IL-12, IL-5, IL-7, IL-1α, GCSF, IL-1β, and TNFα and (3) IL-2, Eotaxin, MIP1β, MIP1α, IL-17, and bFGF. Among the patients with breast cancer, we identified the specific cytokine signature of metastatic patients compared to non-metastatic patients. We also established a mathematical model for distinguishing patients with breast cancer from healthy volunteers and metastatic patients from non-metastatic patients. This cytokine network analysis could provide new insights into early intervention and effective therapeutic strategy for patients with breast cancer.

IL-17B activated mesenchymal stem cells enhance proliferation and migration of gastric cancer cells

Mesenchymal stem cells are important cells in tumor microenvironment. We have previously demonstrated that IL-17B/IL-17RB signal promoted progression of gastric cancer. In this study, we further explored the effect of IL-17B on mesenchymal stem cells in tumor microenvironment and its impact on the tumor progression. The results showed that IL-17B induced the expression of stemness-related genes Nanog, Sox2, and Oct4 in mesenchymal stem cells and enhanced its tumor-promoting effect. The supernatant from cultured mesenchymal stem cells after treating with exogenous rIL-17B promoted the proliferation and migration of MGC-803, therefor suggesting that rIL-17B might promote mesenchymal stem cells to produce soluble factors. In addition, rIL-17B also activated the NF-κΒ, STAT3, β-catenin pathway in mesenchymal stem cells. Our data revealed a new mechanism that IL-17B enhanced the progression of gastric cancer by activating mesenchymal stem cells.

Transcriptome Profiling of IL-17A Preactivated Mesenchymal Stem Cells: A Comparative Study to Unmodified and IFN-γ Modified Mesenchymal Stem Cells

Human mesenchymal stem cells pretreatment with IL-17A (MSC-17) potently enhances T cell immunosuppression but not their immunogenicity, in addition to avidly promoting the induction of suppressive regulatory T cells. The aim of this study was to identify potential mechanisms by which human MSC-17 mediate their superior immunomodulatory function. Untreated-MSC (UT-MSC), IFN-γ treated MSC (MSC-γ), and MSC-17 were assessed for their gene expression profile by microarray. Significantly regulated genes were identified for their biological functions (Database for Annotation, Visualisation and Integrated Discovery, DAVID). Microarray analyses identified 1278 differentially regulated genes between MSC-γ and UT-MSC and 67 genes between MSC-17 and UT-MSC. MSC-γ were enriched for genes involved in immune response, antigen processing and presentation, humoral response, and complement activation, consistent with increased MSC-γ immunogenicity. MSC-17 genes were associated with chemotaxis response, which may be involved in T cell recruitment for MSC-17 immunosuppression. MMP1, MMP13, and CXCL6 were highly and specifically expressed in MSC-17, which was further validated by real-time PCR. Thus, MMPs and chemokines may play a key role in mediating MSC-17 superior immunomodulatory function. MSC-17 represent a potential cellular therapy to suppress immunological T cell responses mediated by expression of an array of immunoregulatory molecules.

Transplantation of RADA16-BDNF peptide scaffold with human umbilical cord mesenchymal stem cells forced with CXCR4 and activated astrocytes for repair of traumatic brain injury

Due to the poor self-regeneration of brain tissue, stem cell transplantation therapy is purported to enable the replacement of lost neurons after traumatic brain injury (TBI). The main challenge of brain regeneration is whether the transplanted cells can survive and carry out neuronal functions in the lesion area. The brain is a complex neuronal network consisting of various types of cells that significantly influence on each other, and the survival of the implanted stem cells in brain is critically influenced by the surrounding cells. Although stem cell-based therapy is developing rapidly, most previous studies just focus on apply single type of stem cells as cell source. Here, we found that co-culturing human umbilical cord mesenchymal stem cells (hUC-MSCs) directly with the activated astrocytes benefited to the proliferation and neuron differentiation of hUC-MSCs in vitro. In this study, hUC-MSCs and the activated astrocytes were seeded in RADA16-BDNF peptide scaffold (R-B-SPH scaffold), a specifical self-assembling peptide hydrogel, in which the environment promoted the differentiation of typical neuron-like cells with neurites extending in three-dimensional directions. Moreover, the results showed co-culture of hUC-MSCs and activated astrocytes promoted more BDNF secretion which may benefit to both neural differentiation of ectogenic hUC-MSCs and endogenic neurogenesis. In order to promote migration of the transplanted hUC-MSCs to the host brain, the hUC-MSCs were forced with CXC chemokine receptor 4 (CXCR4). We found that the moderate-sized lesion cavity, but not the large cavity caused by TBI was repaired via the transplantation of hUC-MSCs^CXCR4 and activated astrocytes embedded in R-B-SPH scaffolds. The functional neural repair for TBI demonstrated in this study is mainly due to the transplantation system of double cells, hUC-MSCs and activated astrocytes. We believe that this novel cell transplantation system offers a promising treatment option for cell replacement therapy for TBI.

STATEMENT OF SIGNIFICANCE

In this reach, we specifically linked RGIDKRHWNSQ, a functional peptide derived from BDNF, to the C-terminal of RADARADARADARADA (RADA16) to structure a functional self-assembling peptide hydrogel scaffold, RADA16-BDNF (R-B-SPH scaffold) for the better transplantation of the double cell unit. Also, the novel scaffold was used as cell-carrier for transplantation double cell unit (hUC-MSCs/astrocyte) for treating traumatic brain injury. The results of this study showing that R-B-SPH scaffold was pliancy and flexibility to fit the brain lesion cavity and promotes the outgrowth of axons and dendrites of the neurons derived from hUC-MSCs in vitro and in vivo, indicating the 3D R-B-SPH scaffold provided a suitable microenvironment for hUC-MSC survival, proliferation and differentiation. Also, our results showing the double-cells transplantation system (hUC-MSCs/astrocyte) may be a novel cell-based therapeutic strategy for neuroregeneration after TBI with potential value for clinical application.

Interferon‑γ alters the microRNA profile of umbilical cord‑derived mesenchymal stem cells

Numerous studies have demonstrated that interferon-γ (IFN-γ) is an important inflammatory cytokine, which may activate the immunomodulatory abilities of mesenchymal stem cells (MSCs), and may influence certain other functions of these cells. MicroRNAs are small non-coding RNAs that regulate the majority of the biological functions of cells and are important in a variety of biological processes. However, few studies have been performed to investigate whether IFN-γ affects the microRNA profile of MSCs. The aim of the present study was to analyze the microRNA profile of MSCs derived from the umbilical cord (UC-MSCs) cultured in the presence or absence of IFN-γ (IFN-UC-MSCs). An array that detects 754 microRNAs was used to determine the expression profiles. Statistical analysis of the array data revealed that 8 microRNAs were significantly differentially expressed in UC-MSCs and IFN-UC-MSCs. Reverse transcription-quantitative polymerase chain reaction validated the differential expression of the 8 identified microRNAs. The target genes of the 8 microRNAs were predicted through two online databases, TargetScan and miRanda, and the predicted results were screened by bioinformatics analysis. The majority of the target genes were involved in the regulation of transcription, signal transduction, proliferation, differentiation and migration. These results may provide insight into the mechanism underlying the regulation of the biological functions of MSCs by IFN-γ, in particular the immunomodulatory activity.

Interleukin-17A-Induced Human Mesenchymal Stem Cells Are Superior Modulators of Immunological Function

Interferon-γ (IFN-γ)-preactivated mesenchymal stem cells (MSC-γ) are highly immunosuppressive but immunogenic in vivo due to their inherent expression of major histocompatibility (MHC) molecules. Here, we present an improved approach where we modified human bone marrow-derived MSC with interleukin-17A (MSC-17) to enhance T cell immunosuppression but not their immunogenicity. MSC-17, unlike MSC-γ, showed no induction or upregulation of MHC class I, MHC class II, and T cell costimulatory molecule CD40, but maintained normal MSC morphology and phenotypic marker expression. When cocultured with phytohemagglutinin (PHA)-activated human T cells, MSCs-17 were potent suppressors of T cell proliferation. Furthermore, MSC-17 inhibited surface CD25 expression and suppressed the elaboration of Th1 cytokines, IFN-γ, tumor necrosis factor-α (TNF-α), and IL-2 when compared with untreated MSCs (UT-MSCs). T cell suppression by MSC-17 correlated with increased IL-6 but not with indoleamine 2,3-dioxygenase 1, cyclooxygenase 1, and transforming growth factor β-1. MSC-17 but not MSC-γ consistently induced CD4(+) CD25(high) CD127(low) FoxP3(+) regulatory T cells (iTregs) from PHA-activated CD4(+) CD25(-) T cells. MSC-induced iTregs expressed CD39, CD73, CD69, OX40, cytotoxic T-lymphocyte associated antigen-4 (CTLA-4), and glucocorticoid-induced TNFR-related protein (GITR). These suppressive MSCs-17 can engender Tregs to potently suppress T cell activation with minimal immunogenicity and thus represent a superior T cell immunomodulator for clinical application.

Interleukin-17 and its implication in the regulation of differentiation and function of hematopoietic and mesenchymal stem cells

Adult stem cells have a great potential applicability in regenerative medicine and cell-based therapies. However, there are still many unresolved issues concerning their biology, and the influence of the local microenvironment on properties of stem cells has been increasingly recognized. Interleukin (IL-) 17, as a cytokine implicated in many physiological and pathological processes, should be taken into consideration as a part of a regulatory network governing tissue-associated stem cells' fate. This review is focusing on the published data on the effects of IL-17 on the properties and function of hematopoietic and mesenchymal stem cells and trying to discuss that IL-17 achieves many of its roles by acting on adult stem cells.

Urokinase type plasminogen activator mediates Interleukin-17-induced peripheral blood mesenchymal stem cell motility and transendothelial migration

Mesenchymal stem cells (MSCs) have the potential to migrate toward damaged tissues increasing tissue regeneration. Interleukin-17 (IL-17) is a proinflammatory cytokine with pleiotropic effects associated with many inflammatory diseases. Although IL-17 can modulate MSC functions, its capacity to regulate MSC migration is not well elucidated so far. Here, we studied the role of IL-17 on peripheral blood (PB) derived MSC migration and transmigration across endothelial cells. IL-17 increased PB-MSC migration in a wound healing assay as well as cell mobilization from collagen gel. Concomitantly IL-17 induced the expression of urokinase type plasminogen activator (uPA) without affecting matrix metalloproteinase expression. The incremented uPA expression mediated the capacity of IL-17 to enhance PB-MSC migration in a ERK1,2 MAPK dependent way. Also, IL-17 induced PB-MSC migration alongside with changes in cell polarization and uPA localization in cell protrusions. Moreover, IL-17 increased PB-MSC adhesion to endothelial cells and transendothelial migration, as well as increased the capacity of PB-MSC adhesion to fibronectin, in an uPA-dependent fashion. Therefore, our data suggested that IL-17 may act as chemotropic factor for PB-MSCs by incrementing cell motility and uPA expression during inflammation development.

Effects of Interleukin-17A on Osteogenic Differentiation of Isolated Human Mesenchymal Stem Cells

OBJECTIVES

Rheumatoid arthritis (RA) is characterized by defective bone repair and excessive destruction and ankylosing spondylitis (AS) by increased ectopic bone formation with syndesmophytes. Since TNF-α and IL-17A are involved in both diseases, this study investigated their effects on the osteogenic differentiation of isolated human bone marrow-derived mesenchymal stem cells (hMSCs).

METHODS

Differentiation of hMSCs into osteoblasts was induced in the presence or absence of IL-17A and/or TNF-α. Matrix mineralization (MM) was evaluated by alizarin red staining and alkaline phosphatase (ALP) activity. mRNA expression was measured by qRT-PCR for bone morphogenetic protein (BMP)-2 and Runx2, genes associated with osteogenesis, DKK-1, a negative regulator of osteogenesis, Schnurri-3 and receptor activator of nuclear factor kappa B ligand (RANKL), associated with the cross talk with osteoclasts, and TNF-α receptor type I and TNF-α receptor type II (TNFRII).

RESULTS

TNF-α alone increased both MM and ALP activity. IL-17A alone increased ALP but not MM. Their combination was more potent. TNF-α alone increased BMP2 mRNA expression at 6 and 12 h. These levels decreased in combination with IL-17A at 6 h only. DKK-1 mRNA expression was inhibited by TNF-α and IL-17A either alone or combined. Supporting an imbalance toward osteoblastogenesis, RANKL expression was inhibited by TNF-α and IL-17A. However, TNF-α but not IL-17 alone decreased Runx2 mRNA expression at 6 h. In parallel, TNF-α but not IL-17 alone increased Schnurri-3 expression with a synergistic effect with their combination. This may be related to an increase of TNFRII overexpression.

CONCLUSION

IL-17 increased the effects of TNF-α on bone matrix formation by hMSCs. However, IL-17 decreased the TNF-α-induced BMP2 inhibition. Synergistic interactions between TNF-α and IL-17 were seen for RANKL inhibition and Schnurri-3 induction. Such increase of Schnurri-3 may in turn activate osteoclasts leading to bone destruction as in RA. Conversely, in the absence of osteoclasts, this could promote ectopic bone formation as in AS.