Comparison of similar cells: Mesenchymal stromal cells and fibroblasts

Development of multilayered artificial urethra graft for urethroplasty

To enhance the treatment of patients' urethral defects, such as strictures and hypospadias, we investigated the potential of using artificial urethral tissue. Our study aimed to generate this tissue and assess its effectiveness in a rabbit model. Two types of bioprinted grafts, based on methacrylated gelatin-silk fibroin (GelMA-SF) hydrogels, were produced: acellular, as well as loaded with autologous rabbit stem cells. Rabbit adipose stem cells (RASC) were differentiated toward smooth muscle in the GelMA-SF hydrogel, while rabbit buccal mucosa stem cells (RBMC), differentiated toward the epithelium, were seeded on its surface, forming two layers of the cell-laden tissue. The constructs were then reinforced with polycaprolactone-polylactic acid meshes to create implantable multilayered artificial urethral grafts. In vivo experiments showed that the cell-laden tissue integrated into the urethra with less fibrosis and inflammation compared to its acellular counterpart. Staining to trace the implanted cells confirmed integration into the host organism 3 months postsurgery.

Mesenchymal stromal cells reduce inflammation and improve lung function in a mouse model of cystic fibrosis lung disease

Mesenchymal stromal cells (MSCs) are multipotent adult stem cells which possess immunomodulatory and repair capabilities. In this study, we investigated whether MSC therapy could modulate inflammation and lung damage in the lungs of Scnn1b-transgenic mice overexpressing the β-subunit of the epithelial sodium channel (β-ENaC), a model with features of Cystic Fibrosis lung disease. Human bone marrow derived MSC cells were intravenously delivered to mice, prior to collection of bronchoalveolar lavage (BALF) and tissue. BALF analysis revealed a significant reduction in inflammatory cells after MSC administration, with both monocytic cells and neutrophils significantly reduced. Pro-inflammatory cytokines keratinocyte-derived chemokine (KC) and osteopontin were also significantly reduced. Histological tissue analysis revealed a reduction in emphysema in Scnn1b-TG mice treated with MSCs and consistent with these findings, improvements in lung function after MSC therapy were observed. Furthermore, MSCs enhanced Ki67 staining in alveolar cells, which may indicate regeneration of the destroyed parenchyma. Mechanistically, restoration of peroxisome proliferator-activated receptor-γ (PPARγ) expression and its transcriptional program were identified after MSC treatment. Our data demonstrate that MSC therapy can reduce inflammation, damage, and lung function decline in the chronically inflamed lung of Scnn1b-Tg mice, suggesting that MSCs may provide an effective tool in the treatment of muco-obstructive diseases such as cystic fibrosis.

An oncolytic HAdV-5 with reduced surface charge combines diminished toxicity and improved tumor targeting

Human adenovirus type 5 (HAdV-5)-based oncolytic viruses hold significant promise for anti-cancer therapy. However, poor tumor-targeting and off-target organ transduction after systemic administration limit their therapeutic efficacy. In addition, the strong liver tropism of HAdV-5-based vectors poses the risk of hepatotoxicity. By genetic modification of the major capsid protein hexon we generated a HAdV-5-based oncolytic vector (HAdV-5-HexPos3) with reduced negative surface charge. Coxsackie and adenovirus receptor (CAR) binding-ablated (ΔCAR) HAdV-5-HexPos3_ΔCAR exhibited superior and CAR-independent transduction of various cancer cell lines in vitro, further enhanced in the presence of HAdV-5 naive murine plasma. Upon intravenous administration into tumor-bearing immunodeficient NSG mice, replication-deficient HAdV-5-HexPos3_ΔCAR vector particles showed significantly reduced off-target organ tropism in all tissues analyzed, including the liver. Moreover, we detected a significantly increased intratumoral vector load for HAdV-5-HexPos3_ΔCAR, leading to a 29-fold elevated tumor-to-liver ratio compared with a control vector with unmodified hexon. Intravenous injection of a conditionally replicating hexon-unmodified control vector induced severe hepatotoxicity in tumor-bearing NSG mice, while a conditionally replicating HAdV-5-HexPos3_ΔCAR vector was well tolerated and resulted in intratumoral vector presence for up to 56 days. HAdV-5-HexPos3_ΔCAR represents a promising vector platform for the generation of HAdV-5-based oncolytic viruses with reduced systemic toxicity and improved therapeutic efficacy.

Fibroblast Heterogeneity in Inflammatory Bowel Disease

Intestinal fibroblasts are pivotal players in maintaining tissue homeostasis and orchestrating responses to injury and inflammation within the gastrointestinal (GI) tract. Fibroblasts contribute significantly to the pathogenesis of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis (UC), by secreting pro-inflammatory cytokines, modulating immune cell activity, and promoting fibrosis. In addition, fibroblasts play crucial roles in tissue repair and regeneration following acute injury or chronic inflammation. The dysregulation of fibroblast functions can lead to fibrotic complications, such as intestinal strictures and obstruction, which are common in advanced stages of IBD. Understanding the complex interplay between fibroblasts and other cell types in the intestine is essential to elucidate the underlying mechanisms of intestinal diseases and identify novel therapeutic targets. Future research aimed at deciphering the heterogeneity of intestinal fibroblasts and their dynamic roles in disease progression holds promise for the development of precision therapies to mitigate fibrosis and inflammation in intestinal disorders.

Research Progress of Fibroblasts in Human Diseases

Fibroblasts, which originate from embryonic mesenchymal cells, are the predominant cell type seen in loose connective tissue. As the main components of the internal environment that cells depend on for survival, fibroblasts play an essential role in tissue development, wound healing, and the maintenance of tissue homeostasis. Furthermore, fibroblasts are also involved in several pathological processes, such as fibrosis, cancers, and some inflammatory diseases. In this review, we analyze the latest research progress on fibroblasts, summarize the biological characteristics and physiological functions of fibroblasts, and delve into the role of fibroblasts in disease pathogenesis and explore treatment approaches for fibroblast-related diseases.

Novel Gene Biomarkers Specific to Human Mesenchymal Stem Cells Isolated from Bone Marrow

In this paper, we present a comparative analysis of the transcriptomic profile of three different human cell types: hematopoietic stem cells (HSCs), bone marrow-derived mesenchymal stem cells (MSCs) and fibroblasts (FIBs). The work aims to identify unique genes that are differentially expressed as specific markers of bone marrow-derived MSCs, and to achieve this undertakes a detailed analysis of three independent datasets that include quantification of the global gene expression profiles of three primary cell types: HSCs, MSCs and FIBs. A robust bioinformatics method, called GlobalTest, is used to assess the specific association between one or more genes expressed in a sample and the outcome variable, that is, the 'cell type' provided as a single univariate response. This outcome variable is predicted for each sample tested, based on the expression profile of the specific genes that are used as input to the test. The precision of the tests is calculated along with the statistical sensitivity and specificity for each gene in each dataset, yielding four genes that mark MSCs with high accuracy. Among these, the best performer is the protein-coding gene Transgelin (TAGLN, Gene ID: 6876) (with a Positive Predictive Value > 0.96 and FDR < 0.001), which identifies MSCs better than any of the currently used standard markers: ENG (CD105), THY1 (CD90) or NT5E (CD73). The results are validated by RT-qPCR, providing novel gene biomarkers specific for human MSCs.

The Macrophage-Fibroblast Dipole in the Context of Cardiac Repair and Fibrosis

Stromal and immune cells and their interactions have gained the attention of cardiology researchers and clinicians in recent years as their contribution in cardiac repair is increasingly recognized. The repair process in the heart is a particularly critical constellation of complex molecular and cellular events and interactions that characteristically fail to ensure adequate recovery following injury, insult, or exposure to stress conditions in this regeneration-hostile organ. The tremendous consequence of this pronounced inability to maintain homeostatic states is being translated in numerous ways promoting progress into heart failure, a deadly, irreversible condition requiring organ transplantation. Fibrosis is in fact a repair response eventually promoting cardiac dysfunction and cardiac fibroblasts are the major cellular players in this process, overproducing collagens and other extracellular matrix components when activated. On the other hand, macrophages may differentially affect fibroblasts and cardiac repair depending on their status and subsets. The opposite interaction is also probable. We discuss here the multifaceted aspects and crosstalk of this cell dipole and the opportunities it may offer for beneficial manipulation approaches that will hopefully lead to progress in heart disease interventions.

Single-cell sequencing technology in skin wound healing

Skin wound healing is a complicated biological process that mainly occurs in response to injury, burns, or diabetic ulcers. It can also be triggered by other conditions such as dermatitis and melanoma-induced skin cancer. Delayed healing or non-healing after skin injury presents an important clinical issue; therefore, further explorations into the occurrence and development of wound healing at the cellular and molecular levels are necessary. Single-cell sequencing (SCS) is used to sequence and analyze the genetic messages of a single cell. Furthermore, SCS can accurately detect cell expression and gene sequences. The use of SCS technology has resulted in the emergence of new concepts pertaining to wound healing, making it an important tool for studying the relevant mechanisms and developing treatment strategies. This article discusses the application value of SCS technology, the effects of the latest research on skin wound healing, and the value of SCS technology in clinical applications. Using SCS to determine potential biomarkers for wound repair will serve to accelerate wound healing, reduce scar formation, optimize drug delivery, and facilitate personalized treatments.

Leveraging Cell Migration Dynamics to Discriminate Between Senescent and Presenescent Human Mesenchymal Stem Cells

Purpose

The suboptimal clinical performance of human mesenchymal stem cells (hMSCs) has raised concerns about their therapeutic potential. One major contributing factor to this issue is the heterogeneous nature of hMSCs. Senescent cell accumulation during stem cell expansion is a key driver of MSC heterogeneity. Current methodologies to eradicate senescent hMSCs have either shown limited success or lack clinical relevance. This study leverages the inherent capacity of hMSCs to migrate toward damaged tissues as a means to discern senescent from presenescent stem cells. Given the established deficiency of senescent cells to migrate through physiologically relevant environments, we hypothesized that a microfluidic device, designed to emulate key facets of in vivo cell motility, could serve as a platform for identifying presenescent cells.

Methods

We employed a Y-shaped microchannel assay, which allows fine-tuning of fluid flow rates and the degree of confinement.

Results

Highly migratory hMSCs detected by the device not only demonstrate increased speed, smaller size, and higher proliferative capacity but also manifest reduced DNA damage and senescence compared to non-migratory cells. Additionally, this assay detects presenescent cells in experiments with mixed early and late passage cells. The introduction of fluid flow through the device can further increase the fraction of highly motile stem cells, improving the assay's effectiveness to remove senescent hMSCs.

Conclusions

Collectively, this assay facilitates the detection and isolation of a highly potent stem cell subpopulation. Given the positive correlation between the migratory potential of administered MSCs and the long-term clinical outcome, delivering homogeneous, highly motile presenescent hMSCs may benefit patient outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-024-00807-0.

Activin A Is a Master Regulator of Phenotypic Switch in Adipose Stromal Cells Initiated by Activated Immune Cell-Secreted Interleukin-1β

Prolonged tissue ischemia and inflammation lead to organ deterioration and are often accompanied by microvasculature rarefaction, fibrosis, and elevated systemic Activin A (ActA), the level of which frequently correlates with disease severity. Mesenchymal stromal cells are prevalent in the perivascular niche and are likely involved in tissue homeostasis and pathology. This study investigated the effects of inflammatory cells on modulation of phenotype of adipose mesenchymal stromal cells (ASC) and the role of ActA in this process. Peripheral blood mononuclear cells were activated with lipopolysaccharide (activated peripheral blood mononuclear cells [aPBMC]) and presented to ASC. Expression of smooth muscle/myofibroblast markers, ActA, transforming growth factors beta 1-3 (TGFβ1-3), and connective tissue growth factor (CTGF) was assessed in ASC. Silencing approaches were used to dissect the signaling cascade of aPBMC-induced acquisition of myofibroblast phenotype by ASC. ASC cocultured with aPBMC or exposed to the secretome of aPBMC upregulated smooth muscle cell markers alpha smooth muscle actin (αSMA), SM22α, and Calponin I; increased contractility; and initiated expression of ActA. Interleukin (IL)-1β was sufficient to replicate this response, whereas blocking IL-1β eliminated aPBMC effects. ASC-derived ActA stimulated CTGF and αSMA expression in ASC; the latter independent of CTGF. Induction of αSMA in ASC by IL-1β or ActA-enriched media relied on extracellular enzymatic activity. ActA upregulated mRNA levels of several extracellular matrix proteins in ASC, albeit to a lesser degree than TGFβ1, and marginally increased cell contractility. In conclusion, the study suggests that aPBMC induce myofibroblast phenotype with weak fibrotic activity in perivascular progenitors, such as ASC, through the IL-1β-ActA signaling axis, which also promotes CTGF secretion, and these effects require ActA extracellular enzymatic processing.

Unveiling the Differentiation Potential of Ovarian Theca Interna Cells from Multipotent Stem Cell-like Cells

RESEARCH QUESTION

Theca interna cells (TICs) are an indispensable cell source for ovarian follicle development and steroidogenesis. Recent studies have identified theca stem cells (TSCs) in both humans and animals. Interestingly, TSCs express mesenchymal stem cell (MSC)-related markers and can differentiate into mesenchymal lineages. MSCs are promising for tissue engineering and regenerative medicine due to their self-renewal and differentiation abilities. Therefore, this study investigated the potential origin of TICs from MSCs.

DESIGN

Whole ovaries from postmenopausal organ donors were obtained, and their cortex was cryopreserved prior to the isolation of stromal cells. These isolated cells were differentiated in vitro to TICs using cell media enriched with various growth factors and hormones. Immunocytochemistry, an enzyme-linked immunosorbent assay, flow cytometry, and reverse transcription-quantitative polymerase chain were employed at different timepoints. Data were analyzed using one-way ANOVA.

RESULTS

Immunocytochemistry showed an increase in TIC markers from day 0 to day 8 and a significant rise in MSC-like markers on day 2. This corresponds with rising androstenedione levels from day 2 to day 13. Flow cytometry identified a decreasing MSC-like cell population from day 2 onwards. The CD13+ cell population and its gene expression increased significantly over time. NGFR and PDGFRA expression was induced on days 0 and 2, respectively, compared to day 13.

CONCLUSIONS

This study offers insights into MSC-like cells as the potential origin of TICs. Differentiating TICs from these widely accessible MSCs holds potential significance for toxicity studies and investigating TIC-related disorders like polycystic ovary syndrome (PCOS).

Bone Marrow Mesenchymal Stem Cells Promote Ovarian Cancer Cell Proliferation via Cytokine Interactions

Bone marrow mesenchymal stem cells (BMSCs) are key players in promoting ovarian cancer cell proliferation, orchestrated by the dynamic interplay between cytokines and their interactions with immune cells; however, the intricate crosstalk among BMSCs and cytokines has not yet been elucidated. Here, we aimed to investigate interactions between BMSCs and ovarian cancer cells. We established BMSCs with a characterized morphology, surface marker expression, and tri-lineage differentiation potential. Ovarian cancer cells (SKOV3) cultured with conditioned medium from BMSCs showed increased migration, invasion, and colony formation, indicating the role of the tumor microenvironment in influencing cancer cell behavior. BMSCs promoted SKOV3 tumorigenesis in nonobese diabetic/severe combined immunodeficiency mice, increasing tumor growth. The co-injection of BMSCs increased the phosphorylation of p38 MAPK and GSK-3β in SKOV3 tumors. Co-culturing SKOV3 cells with BMSCs led to an increase in the expression of cytokines, especially MCP-1 and IL-6. These findings highlight the influence of BMSCs on ovarian cancer cell behavior and the potential involvement of specific cytokines in mediating these effects. Understanding these mechanisms will highlight potential therapeutic avenues that may halt ovarian cancer progression.

A de novo dominant-negative variant is associated with OTULIN-related autoinflammatory syndrome

OTULIN-related autoinflammatory syndrome (ORAS), a severe autoinflammatory disease, is caused by biallelic pathogenic variants of OTULIN, a linear ubiquitin-specific deubiquitinating enzyme. Loss of OTULIN attenuates linear ubiquitination by inhibiting the linear ubiquitin chain assembly complex (LUBAC). Here, we report a patient who harbors two rare heterozygous variants of OTULIN (p.P152L and p.R306Q). We demonstrated accumulation of linear ubiquitin chains upon TNF stimulation and augmented TNF-induced cell death in mesenchymal stem cells differentiated from patient-derived iPS cells, which confirms that the patient has ORAS. However, although the de novo p.R306Q variant exhibits attenuated deubiquitination activity without reducing the amount of OTULIN, the deubiquitination activity of the p.P152L variant inherited from the mother was equivalent to that of the wild-type. Patient-derived MSCs in which the p.P152L variant was replaced with wild-type also exhibited augmented TNF-induced cell death and accumulation of linear chains. The finding that ORAS can be caused by a dominant-negative p.R306Q variant of OTULIN furthers our understanding of disease pathogenesis.

Inter-laboratory multiplex bead-based surface protein profiling of MSC-derived EV preparations identifies MSC-EV surface marker signatures

Mesenchymal stromal cells (MSCs) are promising regenerative therapeutics that primarily exert their effects through secreted extracellular vesicles (EVs). These EVs - being small and non-living - are easier to handle and possess advantages over cellular products. Consequently, the therapeutic potential of MSC-EVs is increasingly investigated. However, due to variations in MSC-EV manufacturing strategies, MSC-EV products should be considered as highly diverse. Moreover, the diverse array of EV characterisation technologies used for MSC-EV characterisation further complicates reliable interlaboratory comparisons of published data. Consequently, this study aimed to establish a common method that can easily be used by various MSC-EV researchers to characterise MSC-EV preparations to facilitate interlaboratory comparisons. To this end, we conducted a comprehensive inter-laboratory assessment using a novel multiplex bead-based EV flow cytometry assay panel. This assessment involved 11 different MSC-EV products from five laboratories with varying MSC sources, culture conditions, and EV preparation methods. Through this assay panel covering a range of mostly MSC-related markers, we identified a set of cell surface markers consistently positive (CD44, CD73 and CD105) or negative (CD11b, CD45 and CD197) on EVs of all explored MSC-EV preparations. Hierarchical clustering analysis revealed distinct surface marker profiles associated with specific preparation processes and laboratory conditions. We propose CD73, CD105 and CD44 as robust positive markers for minimally identifying MSC-derived EVs and CD11b, CD14, CD19, CD45 and CD79 as reliable negative markers. Additionally, we highlight the influence of culture medium components, particularly human platelet lysate, on EV surface marker profiles, underscoring the influence of culture conditions on resulting EV products. This standardisable approach for MSC-EV surface marker profiling offers a tool for routine characterisation of manufactured EV products in pre-clinical and clinical research, enhances the quality control of MSC-EV preparations, and hopefully paves the way for higher consistency and reproducibility in the emerging therapeutic MSC-EV field.

Perturbed collagen metabolism underlies lymphatic recanalization failure in Gata2 heterozygous deficient mice

Lymphedema has become a global health issue following the growing number of cancer surgeries. Curative or supportive therapeutics have long been awaited for this refractory condition. Transcription factor GATA2 is crucial in lymphatic development and maintenance, as GATA2 haploinsufficient disease often manifests as lymphedema. We recently demonstrated that Gata2 heterozygous deficient mice displayed delayed lymphatic recanalization upon lymph node resection. However, whether GATA2 contributes to lymphatic regeneration by functioning in the damaged lymph vessels' microenvironment remains explored. In this study, our integrated analysis demonstrated that dermal collagen fibers were more densely accumulated in the Gata2 heterozygous deficient mice. The collagen metabolism-related transcriptome was perturbed, and collagen matrix contractile activity was aberrantly increased in Gata2 heterozygous embryonic fibroblasts. Notably, soluble collagen placement ameliorated delayed lymphatic recanalization, presumably by modulating the stiffness of the extracellular matrix around the resection site of Gata2 heterozygous deficient mice. Our results provide valuable insights into mechanisms underlying GATA2-haploinsufficiency-mediated lymphedema and shed light on potential therapeutic avenues for this intractable disease.

Fusariotoxin-Induced Toxicity in Mesenchymal Stem Cells and Fibroblasts: A Comparison Between Differentiated and Undifferentiated Cells

Objectives

Humans are unknowingly exposed to mycotoxins through the consumption of plant-derived foods and processed products contaminated with these toxic compounds. In addition to agricultural losses, Fusarium toxins pose a threat to human health. However, the effects of fusariotoxins on the viability and proliferation of stem cells have not been fully explored. We investigated the cytotoxic effects of deoxynivalenol (DON) and B-trichothecene mix (MIX) on mesenchymal stem cells (MSCs) and the L929 fibroblast cell line.

Materials and Methods

MSCs were isolated from the dental pulp tissue. The doubling time and viability of dental pulp stem cells (DPSCs) and L929 cells were determined using the MTT assay. The following doses of B-trichothecenes (0.25-16 µg/mL; 24 hours and 48 hours) were used to evaluate cytotoxicity. In addition, changes in the confluency-dependent response of DPSCs to DON toxicity were determined. Moreover, we investigated the effect of DON on cell death via acridine orange/ethidium bromide (AO/EB) double staining.

Results

A DON and MIX showed a dose- and time-dependent inhibitory effect on the proliferation of both cells. DPSCs exposed to DON for 48 hours (IC50 = 0.5 μg/mL) were found to be 16-fold more sensitive than L929 cells (IC50 = 8 μg/mL). Compared with a culture with 80% confluency, DPSCs from a 50% confluent culture were more sensitive to varying doses of DON (0.25-4 µg/mL, 24-48 hours). Moreover, AO/EB staining showed that treatment of DPSCs with DON led to a significant increase in cell death (17% for 2.4 µg/mL; 50% for 4.8 µg/mL).

Conclusion

This study reveals that undifferentiated MSCs are significantly more sensitive to DON than differentiated somatic cells (L929). Given that humans are frequently exposed to these mycotoxins, our findings imply that prolonged exposure to them may also have harmful effects on cellular differentiation and embryonic development.

In Vitro Characterization of Reversine-Treated Gingival Fibroblasts and Their Safety Evaluation after In Vivo Transplantation

Reversine is a purine derivative that has been investigated with regard to its biological effects, such as its anticancer properties and, mostly, its ability to induce the dedifferentiation of adult cells, increasing their plasticity. The obtained dedifferentiated cells have a high potential for use in regenerative procedures, such as regenerative dentistry (RD). Instead of replacing the lost or damaged oral tissues with synthetic materials, RD uses stem cells combined with matrices and an appropriate microenvironment to achieve tissue regeneration. However, the currently available stem cell sources present limitations, thus restricting the potential of RD. Based on this problem, new sources of stem cells are fundamental. This work aims to characterize mouse gingival fibroblasts (GFs) after dedifferentiation with reversine. Different administration protocols were tested, and the cells obtained were evaluated regarding their cell metabolism, protein and DNA contents, cell cycle changes, morphology, cell death, genotoxicity, and acquisition of stem cell characteristics. Additionally, their teratoma potential was evaluated after in vivo transplantation. Reversine caused toxicity at higher concentrations, with decreased cell metabolic activity and protein content. The cells obtained displayed polyploidy, a cycle arrest in the G2/M phase, and showed an enlarged size. Additionally, apoptosis and genotoxicity were found at higher reversine concentrations. A subpopulation of the GFs possessed stem properties, as supported by the increased expression of CD90, CD105, and TERT, the existence of a CD106+ population, and their trilineage differentiation capacity. The dedifferentiated cells did not induce teratoma formation. The extensive characterization performed shows that significant functional, morphological, and genetic changes occur during the dedifferentiation process. The dedifferentiated cells have some stem-like characteristics, which are of interest for RD.

Deciphering maternal-fetal cross-talk in the human placenta during parturition using single-cell RNA sequencing

Labor is a complex physiological process requiring a well-orchestrated dialogue between the mother and fetus. However, the cellular contributions and communications that facilitate maternal-fetal cross-talk in labor have not been fully elucidated. Here, single-cell RNA sequencing (scRNA-seq) was applied to decipher maternal-fetal signaling in the human placenta during term labor. First, a single-cell atlas of the human placenta was established, demonstrating that maternal and fetal cell types underwent changes in transcriptomic activity during labor. Cell types most affected by labor were fetal stromal and maternal decidual cells in the chorioamniotic membranes (CAMs) and maternal and fetal myeloid cells in the placenta. Cell-cell interaction analyses showed that CAM and placental cell types participated in labor-driven maternal and fetal signaling, including the collagen, C-X-C motif ligand (CXCL), tumor necrosis factor (TNF), galectin, and interleukin-6 (IL-6) pathways. Integration of scRNA-seq data with publicly available bulk transcriptomic data showed that placenta-derived scRNA-seq signatures could be monitored in the maternal circulation throughout gestation and in labor. Moreover, comparative analysis revealed that placenta-derived signatures in term labor were mirrored by those in spontaneous preterm labor and birth. Furthermore, we demonstrated that early in gestation, labor-specific, placenta-derived signatures could be detected in the circulation of women destined to undergo spontaneous preterm birth, with either intact or prelabor ruptured membranes. Collectively, our findings provide insight into the maternal-fetal cross-talk of human parturition and suggest that placenta-derived single-cell signatures can aid in the development of noninvasive biomarkers for the prediction of preterm birth.

Effect of Elaeagnus Angustifolia extract on in vitro wound healing of human dermal fibroblast cells

AIM

The purpose of this study was to determine the impact of Elaeagnus Angustifolia extract (EA) on human dermal fibroblast (HDF) survival, migration, and wound healing-related genes.

METHODS

After preparing the hydroalcoholic extract of EA, MTT and scratch tests were used to determine the effect of EA on the viability and migration of HDFs. In addition, the quantitative polymerase chain reaction (q-PCR) was conducted to evaluate the impact of EA on the expression of wound healing-related genes in HDFs.

RESULT

According to the MTT test, a nontoxic concentration of EA (100 µg/ml) was obtained for further investigations. The scratch test results demonstrated that EA improved HDFs' capacity to migrate when compared to the control group. Additionally, q-PCR results revealed that EA could significantly increase wound healing-related genes (VEGF-A, HLA-G5, and IL-6) in comparison with the control group.

CONCLUSIONS

The EA could have a significant impact on the viability and migration of HDFs. Also, EA increased the expression of wound healing-related genes.

Single-cell analysis reveals distinct fibroblast plasticity during tenocyte regeneration in zebrafish

Despite their importance in tissue maintenance and repair, fibroblast diversity and plasticity remain poorly understood. Using single-cell RNA sequencing, we uncover distinct sclerotome-derived fibroblast populations in zebrafish, including progenitor-like perivascular/interstitial fibroblasts, and specialized fibroblasts such as tenocytes. To determine fibroblast plasticity in vivo, we develop a laser-induced tendon ablation and regeneration model. Lineage tracing reveals that laser-ablated tenocytes are quickly regenerated by preexisting fibroblasts. By combining single-cell clonal analysis and live imaging, we demonstrate that perivascular/interstitial fibroblasts actively migrate to the injury site, where they proliferate and give rise to new tenocytes. By contrast, perivascular fibroblast-derived pericytes or specialized fibroblasts, including tenocytes, exhibit no regenerative plasticity. Active Hedgehog (Hh) signaling is required for the proliferation of activated fibroblasts to ensure efficient tenocyte regeneration. Together, our work highlights the functional diversity of fibroblasts and establishes perivascular/interstitial fibroblasts as tenocyte progenitors that promote tendon regeneration in a Hh signaling-dependent manner.

Comparative computational analysis to distinguish mesenchymal stem cells from fibroblasts

Introduction

Mesenchymal stem cells (MSCs) are considered to be the most promising stem cell type for cell-based therapies in regenerative medicine. Based on their potential to home to diseased body sites following a therapeutically application, these cells could (i) differentiate then into organ-specific cell types to locally restore injured cells or, most prominently, (ii) foster tissue regeneration including immune modulations more indirectly by secretion of protective growth factors and cytokines. As tissue-resident stem cells of mesenchymal origin, these cells are morphologically and even molecularly- at least concerning the classical marker genes- indistinguishable from similar lineage cells, particularly fibroblasts.

Methods

Here we used microarray-based gene expression and global DNA methylation analyses as well as accompanying computational tools in order to specify differences between MSCs and fibroblasts, to further unravel potential identity genes and to highlight MSC signaling pathways with regard to their trophic and immunosuppressive action.

Results

We identified 1352 differentially expressed genes, of which in the MSCs there is a strong signature for e.g., KRAS signaling, known to play essential role in stemness maintenance, regulation of coagulation and complement being decisive for resolving inflammatory processes, as well as of wound healing particularly important for their regenerative capacity. Genes upregulated in fibroblasts addressed predominately transcription and biosynthetic processes and mapped morphological features of the tissue. Concerning the cellular identity, we specified the already known HOX code for MSCs, established a potential HOX code for fibroblasts, and linked certain HOX genes to functional cell-type-specific properties. Accompanied methylation profiles revealed numerous regions, especially in HOX genes, being differentially methylated, which might provide additional biomarker potential.

Discussion

Conclusively, transcriptomic together with epigenetic signatures can be successfully be used for the definition (cellular identity) of MSCs versus fibroblasts as well as for the determination of the superior functional properties of MSCs, such as their immunomodulatory potential.

Physicochemical cues are not potent regulators of human dermal fibroblast trans-differentiation

Due to their inherent plasticity, dermal fibroblasts hold great promise in regenerative medicine. Although biological signals have been well-established as potent regulators of dermal fibroblast function, it is still unclear whether physiochemical cues can induce dermal fibroblast trans-differentiation. Herein, we evaluated the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human dermal fibroblast cultures. Our data indicate that tissue culture plastic and collagen type I coating increased cell proliferation and metabolic activity. None of the assessed in vitro microenvironment modulators affected cell viability. Anisotropic surface topography induced bidirectional cell morphology, especially on more rigid (1,000 kPa and 130 kPa) substrates. Macromolecular crowding increased various collagen types, but not fibronectin, deposition. Macromolecular crowding induced globular extracellular matrix deposition, independently of the properties of the substrate. At day 14 (longest time point assessed), macromolecular crowding downregulated tenascin C (in 9 out of the 14 groups), aggrecan (in 13 out of the 14 groups), osteonectin (in 13 out of the 14 groups), and collagen type I (in all groups). Overall, our data suggest that physicochemical cues (such surface topography, substrate rigidity, collagen coating and macromolecular crowding) are not as potent as biological signals in inducing dermal fibroblast trans-differentiation.

Unlocking the Potential of Mesenchymal Stem Cells in Gynecology: Where Are We Now?

Stem cells, with their remarkable capacity for differentiation into diverse cell types, are vital for the development as well as maintenance of health and homeostasis. Two unique abilities set them apart from other cells: self-renewal and the capacity for differentiation. They play important roles in embryogenesis, development, regeneration, and various other processes. Over the last decade, there has been increased interest in their potential use in the treatment of numerous diseases and disorders across multiple fields of medicine in acute, chronic, innate, and acquired diseases. Stem cells are key to maintaining the body's homeostasis and regulating growth and tissue functions. There are several types of stem cells-embryonic, adult, and human-induced pluripotent cells. Currently, mesenchymal stem cells are of great interest due to their regenerative, immunomodulatory, analgesic, and antimicrobial (anti-inflammatory) effects. Recent studies have shown the potent regenerative effect of stem cell therapy in gynecologic diseases such as infertility, Asherman syndrome, lichen sclerosus, polycystic ovary syndrome, premature ovarian insufficiency, genitourinary syndrome of menopause, and rectovaginal fistulas. Moreover, the successful isolation of oogonial stem cells could lead to a revolution in the field of gynecology and the potential treatment of the conditions discussed. This review aims to provide a better understanding of the latest therapeutic options involving stem cells and raise awareness of this promising yet not widely known topic in gynecology and medicine in general.

Cancer-educated mammary adipose tissue-derived stromal/stem cells in obesity and breast cancer: spatial regulation and function

BACKGROUND

Breast cancer is the most frequently diagnosed cancer and a common cause of cancer-related death in women. It is well recognized that obesity is associated with an enhanced risk of more aggressive breast cancer as well as reduced patient survival. Breast adipose tissue-derived mesenchymal stromal/stem cells (bASCs) are crucial components of the tumor microenvironment. A key step initially involved in this process might be the de-differentiation of bASCs into tumor supporting phenotypes.

METHODS

In the present work, we isolated bASCs from adipose tissues adjacent to the tumor (aT bASCs) from lean- (ln-aT bASCs, BMI ≤ 25) and breast cancer patients with obesity (ob-aT bASCs, BMI ≥ 35), and analyzed their phenotypes with functional assays and RNA sequencing, compared to their counterparts isolated from adipose tissues distant from the tumor (dT bASCs).

RESULTS

We show that ln-aT bASCs are susceptible to be transformed into an inflammatory cancer-associated phenotype, whereas ob-aT bASCs are prone to be cancer-educated into a myofibroblastic phenotype. Both ln-aT- and ob-aT bASCs compromise their physiological differentiation capacity, and upregulate metastasis-promoting factors. While ln-aT bASCs stimulate proliferation, motility and chemoresistance by inducing epithelial-mesenchymal transition of low malignant breast cancer cells, ob-aT bASCs trigger more efficiently a cancer stem cell phenotype in highly malignant breast cancer cells.

CONCLUSION

Breast cancer-associated bASCs are able to foster malignancy of breast cancer cells by multiple mechanisms, especially, induction of epithelial-mesenchymal transition and activation of stemness-associated genes in breast cancer cells. Blocking the de-differentiation of bASCs in the tumor microenvironment could be a novel strategy to develop an effective intervention for breast cancer patients.

SIGNIFICANCE

This study provides mechanistic insights into how obesity affects the phenotype of bASCs in the TME. Moreover, it highlights the molecular changes inside breast cancer cells upon cell-cell interaction with cancer-educated bASCs.

An extracellular matrix hydrogel from porcine urinary bladder for tissue engineering: In vitro and in vivo analyses

BACKGROUND

The necessity to manufacture scaffolds with superior capabilities of biocompatibility and biodegradability has led to the production of extracellular matrix (ECM) scaffolds. Among their advantages, they allow better cell colonization, which enables its successful integration into the hosted tissue, surrounding the area to be repaired and their formulations facilitate placing it into irregular shapes. The ECM from porcine urinary bladder (pUBM) comprises proteins, proteoglycans and glycosaminoglycans which provide support and enable signals to the cells. These properties make it an excellent option to produce hydrogels that can be used in regenerative medicine.

OBJECTIVE

The goal of this study was to assess the biocompatibility of an ECM hydrogel derived from the porcine urinary bladder (pUBMh) in vitro using fibroblasts, macrophages, and adipose-derived mesenchymal stem cells (AD-MCSs), as well as biocompatibility in vivo using Wistar rats.

METHODS

Effects upon cells proliferation/viability was measured using MTT assay, cytotoxic effects were analyzed by quantifying lactate dehydrogenase release and the Live/Dead Cell Imaging assay. Macrophage activation was assessed by quantification of IL-6, IL-10, IL-12p70, MCP-1, and TNF-α using a microsphere-based cytometric bead array. For in vivo analysis, Wistar rats were inoculated into the dorsal sub-dermis with pUBMh. The specimens were sacrificed at 24 h after inoculation for histological study.

RESULTS

The pUBMh obtained showed good consistency and absence of cell debris. The biocompatibility tests in vitro revealed that the pUBMh promoted cell proliferation and it is not cytotoxic on the three tested cell lines and induces the production of pro-inflammatory cytokines on macrophages, mainly TNF-α and MCP-1. In vivo, pUBMh exhibited fibroblast-like cell recruitment, without tissue damage or inflammation.

CONCLUSION

The results show that pUBMh allows cell proliferation without cytotoxic effects and can be considered an excellent biomaterial for tissue engineering.

Discovery and characterization of heterogeneous and multipotent fibroblast populations isolated from excised cleft lip tissue

Background

Regularly discarded lip tissue obtained from corrective surgeries to close the cleft lip represents an easily accessible and rich source for the isolation of primary fibroblasts. Primary fibroblasts have been described to show compelling similarities to mesenchymal stem cells (MSCs). Hence, cleft lip and palate (CLP) lip-derived fibroblasts could be thought as an intriguing cell source for personalized regenerative therapies in CLP-affected patients.

Methods

Initially, we thoroughly characterized the fibroblastic nature of the lip-derived mesenchymal outgrowths by molecular and functional assays. Next, we compared their phenotype and genotype to that of bone marrow-mesenchymal stem cells (BM-MSCs) and of human lung-derived fibroblasts WI38, by assessing their morphology, surface marker expression, trilineage differentiation potential, colony-forming (CFU) capacity, and immunomodulation property. Finally, to better decipher the heterogeneity of our CLP cultures, we performed a single cell clonal analysis and tested expanded clones for surface marker expression, as well as osteogenic and CFU potential.

Results

We identified intriguingly similar phenotypic and genotypic properties between CLP lip fibroblasts and BM-MSCs, which makes them distinct from WI38. Furthermore, our own data in combination with the complex anatomy of the lip tissue indicated heterogeneity in our CLP cultures. Using a clonal analysis, we discovered single cell-derived clones with increased levels of the MSC markers CD106 and CD146 and clones with variabilities in their commitment to differentiate into bone-forming cells and in their potential to form single cell-derived colonies. However, we were not able to gain clones possessing superior MSC-like capacities when compared to the heterogeneous parental CLP population. Additionally, all clones could still generate contractile forces and retained robust levels of the fibroblast specific marker FSP1, which was not detectable in BM-MSCs.

Conclusions

Our results suggest that we isolate heterogeneous populations of fibroblasts from discarded CLP lip tissue, which show a prominently multipotent character in their entirety avoiding the need for elaborate subpopulation selections in vitro. These findings suggest that CLP lip fibroblasts might be a novel potential cell source for personalized regenerative medicine of clinical benefit for CLP patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03154-x.

Adipose Tissue-Derived Mesenchymal Stromal/Stem Cells, Obesity and the Tumor Microenvironment of Breast Cancer

Breast cancer is the most frequently diagnosed cancer and a common cause of cancer-related death in women. It is well recognized that obesity is associated with an enhanced risk of more aggressive breast cancer as well as reduced patient survival. Adipose tissue is the major microenvironment of breast cancer. Obesity changes the composition, structure, and function of adipose tissue, which is associated with inflammation and metabolic dysfunction. Interestingly, adipose tissue is rich in ASCs/MSCs, and obesity alters the properties and functions of these cells. As a key component of the mammary stroma, ASCs play essential roles in the breast cancer microenvironment. The crosstalk between ASCs and breast cancer cells is multilateral and can occur both directly through cell-cell contact and indirectly via the secretome released by ASC/MSC, which is considered to be the main effector of their supportive, angiogenic, and immunomodulatory functions. In this narrative review, we aim to address the impact of obesity on ASCs/MSCs, summarize the current knowledge regarding the potential pathological roles of ASCs/MSCs in the development of breast cancer, discuss related molecular mechanisms, underline the possible clinical significance, and highlight related research perspectives. In particular, we underscore the roles of ASCs/MSCs in breast cancer cell progression, including proliferation and survival, angiogenesis, migration and invasion, the epithelial-mesenchymal transition, cancer stem cell development, immune evasion, therapy resistance, and the potential impact of breast cancer cells on ASCS/MSCs by educating them to become cancer-associated fibroblasts. We conclude that ASCs/MSCs, especially obese ASCs/MSCs, may be key players in the breast cancer microenvironment. Targeting these cells may provide a new path of effective breast cancer treatment.

Revisiting Epithelial Carcinogenesis

The origin of cancer remains one of the most important enigmas in modern biology. This paper presents a hypothesis for the origin of carcinomas in which cellular aging and inflammation enable the recovery of cellular plasticity, which may ultimately result in cancer. The hypothesis describes carcinogenesis as the result of the dedifferentiation undergone by epithelial cells in hyperplasia due to replicative senescence towards a mesenchymal cell state with potentially cancerous behavior. In support of this hypothesis, the molecular, cellular, and histopathological evidence was critically reviewed and reinterpreted when necessary to postulate a plausible generic series of mechanisms for the origin and progression of carcinomas. In addition, the implications of this theoretical framework for the current strategies of cancer treatment are discussed considering recent evidence of the molecular events underlying the epigenetic switches involved in the resistance of breast carcinomas. The hypothesis also proposes an epigenetic landscape for their progression and a potential mechanism for restraining the degree of dedifferentiation and malignant behavior. In addition, the manuscript revisits the gradual degeneration of the nonalcoholic fatty liver disease to propose an integrative generalized mechanistic explanation for the involution and carcinogenesis of tissues associated with aging. The presented hypothesis might serve to understand and structure new findings into a more encompassing view of the genesis of degenerative diseases and may inspire novel approaches for their study and therapy.

Gene Therapy in Orthopaedics: Progress and Challenges in Pre-Clinical Development and Translation

In orthopaedics, gene-based treatment approaches are being investigated for an array of common -yet medically challenging- pathologic conditions of the skeletal connective tissues and structures (bone, cartilage, ligament, tendon, joints, intervertebral discs etc.). As the skeletal system protects the vital organs and provides weight-bearing structural support, the various tissues are principally composed of dense extracellular matrix (ECM), often with minimal cellularity and vasculature. Due to their functional roles, composition, and distribution throughout the body the skeletal tissues are prone to traumatic injury, and/or structural failure from chronic inflammation and matrix degradation. Due to a mixture of environment and endogenous factors repair processes are often slow and fail to restore the native quality of the ECM and its function. In other cases, large-scale lesions from severe trauma or tumor surgery, exceed the body’s healing and regenerative capacity. Although a wide range of exogenous gene products (proteins and RNAs) have the potential to enhance tissue repair/regeneration and inhibit degenerative disease their clinical use is hindered by the absence of practical methods for safe, effective delivery. Cumulatively, a large body of evidence demonstrates the capacity to transfer coding sequences for biologic agents to cells in the skeletal tissues to achieve prolonged delivery at functional levels to augment local repair or inhibit pathologic processes. With an eye toward clinical translation, we discuss the research progress in the primary injury and disease targets in orthopaedic gene therapy. Technical considerations important to the exploration and pre-clinical development are presented, with an emphasis on vector technologies and delivery strategies whose capacity to generate and sustain functional transgene expression in vivo is well-established.

Human Amniotic Mesenchymal Stem Cells and Fibroblasts Accelerate Wound Repair of Cystic Fibrosis Epithelium

Cystic fibrosis (CF) airways are affected by a deranged repair of the damaged epithelium resulting in altered regeneration and differentiation. Previously, we showed that human amniotic mesenchymal stem cells (hAMSCs) corrected base defects of CF airway epithelial cells via connexin (CX)43-intercellular gap junction formation. In this scenario, it is unknown whether hAMSCs, or fibroblasts sharing some common characteristics with MSCs, can operate a faster repair of a damaged airway epithelium. A tip-based scratch assay was employed to study wound repair in monolayers of CFBE14o- cells (CFBE, homozygous for the F508del mutation). hAMSCs were either co-cultured with CFBE cells before the wound or added to the wounded monolayers. NIH-3T3 fibroblasts (CX43+) were added to wounded cells. HeLa cells (CX43-) were used as controls. γ-irradiation was optimized to block CFBE cell proliferation. A specific siRNA was employed to downregulate CX43 expression in CFBE cells. CFBE cells showed a delayed repair as compared with wt-CFTR cells (16HBE41o-). hAMSCs enhanced the wound repair rate of wounded CFBE cell monolayers, especially when added post wounding. hAMSCs and NIH-3T3 fibroblasts, but not HeLa cells, increased wound closure of irradiated CFBE monolayers. CX43 downregulation accelerated CFBE wound repair rate without affecting cell proliferation. We conclude that hAMSCs and fibroblasts enhance the repair of a wounded CF airway epithelium, likely through a CX43-mediated mechanism mainly involving cell migration.

Extracellular matrix hydrogel derived from bovine bone is biocompatible in vitro and in vivo

BACKGROUND: Nowadays, biomaterials used as a scaffold must be easy to deliver in the bone defect area. Extracellular matrix (ECM) hydrogels are highly hydrated polymers that can fill irregular shapes and act as bioactive materials. OBJECTIVE: This work aims to show the effects of ECM hydrogels derived from bovine bone (bECMh) on proliferation, cytotoxicity and expression of pro-inflammatory cytokines in three cells types involved in tissue regeneration, as well as biocompatibility in vivo. METHODS: In vitro, we used an extract of bECMh to test it on macrophages, fibroblasts, and adipose-derived mesenchymal stem cells (AD-MCSs). Cell proliferation was measured using the MTT assay, cytotoxicity was measured by quantifying lactate dehydrogenase release and the Live/Dead Cell Imaging assays. Concentrations of IL-6, IL-10, IL-12p70, MCP-1 and TNF-α were quantified in the supernatants using a microsphere-based cytometric bead array. For in vivo analysis, Wistar rats were inoculated into the dorsal sub-dermis with bECMh, taking as reference the midline of the back. The specimens were sacrificed at 24 h for histological study. RESULTS: In vitro, this hydrogel behaves as a dynamic biomaterial that increases fibroblast proliferation, induces the production of pro-inflammatory cytokines in macrophages, among which MCP-1 and TNF-α stand out. In vivo, bECMh allows the colonization of host fibroblast-like and polymorphonuclear cells, without tissue damage or inflammation. CONCLUSIONS: The results indicate that bECMh is a biocompatible material that could be used as a scaffold, alone or in conjunction with cells or functional biomolecules, enhancing proliferation and allowing the filling of bone defects to its further regeneration.

Antiosteoporosis Effects, Pharmacokinetics, and Drug Delivery Systems of Icaritin: Advances and Prospects

Osteoporosis is a systemic skeletal disorder affecting over 200 million people worldwide and contributes dramatically to global healthcare costs. Available anti-osteoporotic drug treatments including hormone replacement therapy, anabolic agents, and bisphosphonates often cause adverse events which limit their long-term use. Therefore, the application of natural products has been proposed as an alternative therapy strategy. Icaritin (ICT) is not only an enzyme-hydrolyzed product of icariin but also an intestinal metabolite of eight major flavonoids of the traditional Chinese medicinal plant Epimedium with extensive pharmacological activities, such as strengthening the kidney and reinforcing the bone. ICT displays several therapeutic effects, including osteoporosis prevention, neuroprotection, antitumor, cardiovascular protection, anti-inflammation, and immune-protective effect. ICT inhibits bone resorption activity of osteoclasts and stimulates osteogenic differentiation and maturation of bone marrow stromal progenitor cells and osteoblasts. As for the mechanisms of effect, ICT regulates relative activities of two transcription factors Runx2 and PPARγ, determines the differentiation of MSCs into osteoblasts, increases mRNA expression of OPG, and inhibits mRNA expression of RANKL. Poor water solubility, high lipophilicity, and unfavorable pharmacokinetic properties of ICT restrict its anti-osteoporotic effects, and novel drug delivery systems are explored to overcome intrinsic limitations of ICT. The paper focuses on osteogenic effects and mechanisms, pharmacokinetics and delivery systems of ICT, and highlights bone-targeting strategies to concentrate ICT on the ideal specific site of bone. ICT is a promising potential novel therapeutic agent for osteoporosis.

Single-Cell Transcriptome Integration Analysis Reveals the Correlation Between Mesenchymal Stromal Cells and Fibroblasts

Background: Mesenchymal stromal cells (MSCs) and fibroblasts show similar morphology, surface marker expression, and proliferation, differentiation, and immunomodulatory capacities. These similarities not only blur their cell identities but also limit their application. Methods: We performed single-cell transcriptome sequencing of the human umbilical cord and foreskin MSCs (HuMSCs and FSMSCs) and extracted the single-cell transcriptome data of the bone marrow and adipose MSCs (BMSCs and ADMSCs) from the Gene Expression Omnibus (GEO) database. Then, we performed quality control, batch effect correction, integration, and clustering analysis of the integrated single-cell transcriptome data from the HuMSCs, FMSCs, BMSCs, and ADMSCs. The cell subsets were annotated based on the surface marker phenotypes for the MSCs (CD105 ⁺ , CD90 ⁺, CD73 ⁺, CD45 ^-, CD34 ^-, CD19 ^-, HLA-DRA ^-, and CD11b ^-), fibroblasts (VIM ⁺, PECAM1 ^-, CD34 ^-, CD45 ^-, EPCAM ^-, and MYH11 ^-), and pericytes (CD146 ⁺, PDGFRB ⁺, PECAM1 ^-, CD34 ^-, and CD45 ^-). The expression levels of common fibroblast markers (ACTA2, FAP, PDGFRA, PDGFRB, S100A4, FN1, COL1A1, POSTN, DCN, COL1A2, FBLN2, COL1A2, DES, and CDH11) were also analyzed in all cell subsets. Finally, the gene expression profiles, differentiation status, and the enrichment status of various gene sets and regulons were compared between the cell subsets. Results: We demonstrated 15 distinct cell subsets in the integrated single-cell transcriptome sequencing data. Surface marker annotation demonstrated the MSC phenotype in 12 of the 15 cell subsets. C10 and C14 subsets demonstrated both the MSC and pericyte phenotypes. All 15 cell subsets demonstrated the fibroblast phenotype. C8, C12, and C13 subsets exclusively demonstrated the fibroblast phenotype. We identified 3,275 differentially expressed genes, 305 enriched gene sets, and 34 enriched regulons between the 15 cell subsets. The cell subsets that exclusively demonstrated the fibroblast phenotype represented less primitive and more differentiated cell types. Conclusion: Cell subsets with the MSC phenotype also demonstrated the fibroblast phenotype, but cell subsets with the fibroblast phenotype did not necessarily demonstrate the MSC phenotype, suggesting that MSCs represented a subclass of fibroblasts. We also demonstrated that the MSCs and fibroblasts represented highly heterogeneous populations with distinct cell subsets, which could be identified based on the differentially enriched gene sets and regulons that specify proliferating, differentiating, metabolic, and/or immunomodulatory functions.

Toll-Like Receptors and Dental Mesenchymal Stromal Cells

Dental mesenchymal stromal cells (MSCs) are a promising tool for clinical application in and beyond dentistry. These cells possess multilineage differentiation potential and immunomodulatory properties. Due to their localization in the oral cavity, these cells could sometimes be exposed to different bacteria and viruses. Dental MSCs express various Toll-like receptors (TLRs), and therefore, they can recognize different microorganisms. The engagement of TLRs in dental MSCs by various ligands might change their properties and function. The differentiation capacity of dental MSCs might be either inhibited or enhanced by TLRs ligands depending on their nature and concentrations. Activation of TLR signaling in dental MSCs induces the production of proinflammatory mediators. Additionally, TLR ligands alter the immunomodulatory ability of dental MSCs, but this aspect is still poorly explored. Understanding the role of TLR signaling in dental MSCs physiology is essential to assess their role in oral homeostasis, inflammatory diseases, and tissue regeneration.

Direct Reprogramming of Mice Skin Fibroblasts into Insulin-Producing Cells In Vitro

Transdifferentiation means mature cell conversion into other mature cells. Ethical issues, epigenetic failure, or teratoma development are found in cellular reprogramming strategies. Thus, new methods are needed. This study aimed to develop a new novel formula of chemical molecules and growth factors that differentiate skin fibroblasts into insulin-producing cells (IPCs). Newborn mice fibroblasts differentiated using four induction methods into IPCs to search for the best method. Fibroblasts, stem cells, and pancreatic markers were identified using an immunocytochemistry (ICC) assay. Insulin was measured using ELISA and dithizone (DTZ) assays. The skin fibroblasts were induced successfully into IPCs. The best method to obtain IPCs was indicated by measuring insulin concentration in differentiated cell supernatant from all induced cells by the four methods. The protein expression of the pancreatic markers of induced cells increased with time, as indicated by the ICC assay. OCT3/4 increased on day 9, after which the expression tended to decrease. DTZ-positive clusters were observed on day 16. Secreted insulin of differentiated cells was injected in streptozotocin-induced diabetic mice, which decreased blood glucose levels after injection. This study indicated an efficient new chemical method for transdifferentiating skin fibroblasts into functional IPCs, which is a promising method for diabetes mellitus therapy.

[Regulatory effect of CCN3 on proliferation of mouse embryonic fibroblasts and its mechanism]

OBJECTIVE

To investigate the role of NOV/CCN3 in regulating the proliferation of mesenchymal stem cells (MSCs) and its regulatory mechanism and assess the value of CCN3 as a proliferative factor in bone tissue engineering.

METHODS

Mouse embryonic fibroblasts (MEFs) were used as the MSC model, in which CCN3 expression was up-regulated and downregulated by transfection with the recombinant adenovirus vectors Ad-CCN3 and Ad-siCCN3, respectively. Flow cytometry was used to analyze the changes in cell cycle and apoptosis of the transfected cells. Western blotting was used to detect the expression levels of the proliferation indicators (PCNA, cyclin E, and cyclin B1) and the apoptosis indicators (Bax and Bcl-2) to assess the effect of modulation of CCN3 expression on MEF proliferation and apoptosis. CCN3 protein secretion by the cells was detected using ELISA. RT-qPCR and Western blotting were employed to analyze the changes in the expressions of Notch1, ligand DLL1, the downstream key proteins or genes (Hey1, P300, H3K9) and MAPK pathway-related proteins ERK1+2 and p-ERK1+2.

RESULTS

Flow cytometry showed that compared with the control cells, MEFs transfected with Ad-CCN3 exhibited significantly increased cell proliferation index (P < 0.01) and lowered cell apoptosis rate (P < 0.05) with obviously enhanced expressions of PCNA, cyclin E and Bcl-2 proteins (P < 0.05). The results of RT-qPCR and Western blotting demonstrated that CCN3 overexpression significantly promoted the expression of Notch1 in the Notch signaling pathway (P < 0.001), inhibited the expressions of DLL1, Hey1, P300, and H3K9 (P < 0.05), and increased the protein expressions of ERK1+2 and P-ERk1+2 in the MAPK pathway (P < 0.01).

CONCLUSIONS

CCN3 over-expression promotes the proliferation and inhibits apoptosis of MEFs possibly by inhibiting the classical Notch signaling pathway and activating the MAPK pathway via binding to Notch1, suggesting the potential value of CCN3 as a proliferative factor of MSCs in bone tissue engineering.