TGF-β1 Pretreatment Improves the Function of Mesenchymal Stem Cells in the Wound Bed

Short preconditioning with TGFβ of equine adipose tissue-derived mesenchymal stem cells predisposes towards an anti-fibrotic secretory phenotype: A possible tool for treatment of endometrosis in mares

Endometrosis in mares is a disease resulting from chronic inflammation characterized by peri glandular fibrosis. There is no effective treatment so far, which opens the door for exploring the use of stem cells as a candidate. Transforming growth factor beta (TGFβ) is crucial for the establishment and progression of fibrosis in mare's endometrosis. We aimed to develop regenerative approaches to treat endometrosis by using mesenchymal stem cells (MSC), for which understanding the effect of TGFβ on exogenous MSC is crucial. We isolated and characterized equine adipose MSC from six donors. Cells were pooled and exposed to 10 ng/ml of TGFβ for 0, 4, and 24 h, after which cells were analyzed for proliferation, migration, mesodermal differentiation, expression of fibrosis-related mRNAs, and prostaglandin E2 secretion. At 24 h of exposition to TGFβ, there was a progressive increase in the contraction of the monolayer, leading to nodular structures, while cell viability did not change. Exposure to TGFβ impaired adipogenic and osteogenic differentiation after 4 h of treatment, which was more marked at 24 h, represented by a decrease in Oil red and Alizarin red staining, as well as a significant drop (p < 0.05) in the expression of key gene regulators of differentiation processes (PPARG for adipose and RUNX2 for osteogenic differentiation). TGFβ increased chondrogenic differentiation as shown by the upsurge in size of the resulting 3D cell pellet and intensity of Alcian Blue staining, as well as the significant up-regulation of SOX9 expression (p < 0.05) at 4 h, which reached a maximum peak at 24 h (p < 0.01), indicative of up-regulation of glycosaminoglycan synthesis. Preconditioning MSC with TGFβ led to a significant increase (p < 0.05) in the expression of myofibroblast gene markers aSMA, COL1A1, and TGFβ at 24 h exposition time. In contrast, the expression of COL3A1 did not change with respect to the control but registered a significant downregulation compared to 4 h (p < 0.05). TGFβ also affected the expression of genes involved in PGE2 synthesis and function; COX2, PTGES, and the PGE2 receptor EP4 were all significantly upregulated early at 4 h (p < 0.05). Cells exposed to TGFβ showed a significant upregulation of PGE2 secretion at 4 h compared to untreated cells (p < 0.05); conversely, at 24 h, the PGE2 values decreased significantly compared to control cells (p < 0.05). Preconditioning MSC for 4 h led to an anti-fibrotic secretory phenotype, while a longer period (24 h) led to a pro-fibrotic one. It is tempting to propose a 4-h preconditioning of exogenous MSC with TGFβ to drive them towards an anti-fibrotic phenotype for cellular and cell-free therapies in fibrotic diseases such as endometrosis of mares.

HUC-MSCs combined with platelet lysate treat diabetic chronic cutaneous ulcers in Bama miniature pig

Human umbilical cord mesenchymal stem cells (HUC-MSCs) and platelet lysate (PL) shows potential of wound healing. However, MSCs in combination with PL for wound healing is still lacking. In this study, we presented high glucose cultured wound related cells to mimic diabetic chronic ulcers (DCU) cells, wound healing indicators and the TGFβ/Smad signaling pathway were detected by PL cultured HUC-MSC supernatant (MSC-Sp) in vitro. In vivo study, diabetes was induced in pigs feeding a high-energy diet and multiple injections of streptozotocin (125 mg/kg). Chronic wounds were created on both sides of the backs of seven pigs by surgical creation and foreign body compression for eight weeks before treatment. The wounds were treated with saline control (N = 11), PL (N = 11), HUC- MSCs (N = 18, 6 × 106/mL/cm2), and PL + HUC-MSCs (N = 18, 6 × 106/mL/cm2) respectively. Tissue samples were collected to observe new collagen, neovascularization, wound healing factors, and the TGFβ/Smad signaling pathway. The resulting PL-cultured MSC-Sp promoted the proliferation of keratinocytes, fibroblasts, and vascular endothelial cells and inhibited the TGFβ1/TGFβ3 ratio, upregulated VEGF-α and PDGF-BB production by keratinocytes and fibroblasts, and downregulated the expression of CD86, IL-6, and TNF-α in RAW264.7 cells. PL + HUC-MSCs had the best wound healing rate in vivo, and promoted collagen formation, neovascularization, and inflammation, regulated the balance between IL-6/TGFβ1 and IL-6/Arg-1 and upregulated the expression of VEGF-α and TGFβ1. In summary, PL + HUC-MSCs had a better wound healing effect than HUC-MSCs or PL treatment alone by regulating the IL-6/Arg-1 and IL-6/TGFβ1 balance and upregulating TGFβ1, VEGF-α, Col1, and α-SMA.

Bioactive materials for in vivo sweat gland regeneration

Loss of sweat glands (SwGs) commonly associated with extensive skin defects is a leading cause of hyperthermia and heat stroke. In vivo tissue engineering possesses the potential to take use of the body natural ability to regenerate SwGs, making it more conducive to clinical translation. Despite recent advances in regenerative medicine, reconstructing SwG tissue with the same structure and function as native tissue remains challenging. Elucidating the SwG generation mechanism and developing biomaterials for in vivo tissue engineering is essential for understanding and developing in vivo SwG regenerative strategies. Here, we outline the cell biology associated with functional wound healing and the characteristics of bioactive materials. We critically summarize the recent progress in bioactive material-based cell modulation approaches for in vivo SwG regeneration, including the recruitment of endogenous cells to the skin lesion for SwG regeneration and in vivo cellular reprogramming for SwG regeneration. We discussed the re-establishment of microenvironment via bioactive material-mediated regulators. Besides, we offer promising perspectives for directing in situ SwG regeneration via bioactive material-based cell-free strategy, which is a simple and effective approach to regenerate SwG tissue with both fidelity of structure and function. Finally, we discuss the opportunities and challenges of in vivo SwG regeneration in detail. The molecular mechanisms and cell fate modulation of in vivo SwG regeneration will provide further insights into the regeneration of patient-specific SwGs and the development of potential intervention strategies for gland-derived diseases.

Administration of stem cells against cardiovascular diseases with a focus on molecular mechanisms: Current knowledge and prospects

Cardiovascular diseases (CVDs) are a serious global concern for public and human health. Despite the emergence of significant therapeutic advances, it is still the leading cause of death and disability worldwide. As a result, extensive efforts are underway to develop practical therapeutic approaches. Stem cell-based therapies could be considered a promising strategy for the treatment of CVDs. The efficacy of stem cell-based therapeutic approaches is demonstrated through recent laboratory and clinical studies due to their inherent regenerative properties, proliferative nature, and their capacity to differentiate into different cells such as cardiomyocytes. These properties could improve cardiovascular functioning leading to heart regeneration. The two most common types of stem cells with the potential to cure heart diseases are induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs). Several studies have demonstrated the use, efficacy, and safety of MSC and iPSCs-based therapies for the treatment of CVDs. In this study, we explain the application of stem cells, especially iPSCs and MSCs, in the treatment of CVDs with a focus on cellular and molecular mechanisms and then discuss the advantages, disadvantages, and perspectives of using this technology in the treatment of these diseases.

Senescence-associated exosomes transfer miRNA-induced fibrosis to neighboring cells

Radiation-induced fibrosis is a common side effect of radiotherapy, which is the most common treatment for cancer. However, radiation also causes p53-mediated cell cycle arrest, prolonged expression of p21, and the development of senescence in normal cells that reside in irradiated tissues. Bone marrow-derived mesenchymal stem cells (MSCs) accumulate in primary tumor sites because of their natural tropism for inflammatory and fibrotic tissues. MSCs are extremely sensitive to low doses of ionizing radiation and acquire senescence as a result of bystander radiation effects. Senescent cells remain metabolically active but develop a potent senescence-associated secretory phenotype (SASP) that correlates to hyperactive secretion of cytokines, pro-fibrotic growth factors, and exosomes (EXOs). Integrative pathway analysis highlighted that radiation-induced senescence significantly enriched cell-cycle, extracellular matrix, transforming growth factor-β (TGF-β) signaling, and vesicle-mediated transport genes in MSCs. EXOs are cell-secreted nanovesicles (a subclass of small extracellular vesicles) that contain biomaterials-proteins, RNAs, microRNAs (miRNAs)-that are critical in cell-cell communication. miRNA content analysis of secreted EXOs further revealed that radiation-induced senescence uniquely altered miRNA profiles. In fact, several of the standout miRNAs directly targeted TGF-β or downstream genes. To examine bystander effects of radiation-induced senescence, we further treated normal MSCs with senescence-associated EXOs (SA-EXOs). These modulated genes related to TGF-β pathway and elevated both alpha smooth muscle actin (protein increased in senescent, activated cells) and Ki-67 (proliferative marker) expression in SA-EXO treated MSCs compared to untreated MSCs. We revealed SA-EXOs possess unique miRNA content that influence myofibroblast phenotypes via TGF-β pathway activation. This highlights that SA-EXOs are potent SASP factors that play a large role in cancer-related fibrosis.

Lipid-mediated ex vivo cell surface engineering for augmented cellular functionalities

Once administrated, intercellular adhesion to recognize and/or arrest target cells is essential for specific treatments, especially for cancer or tumor. However, immune cells administrated into the tumor-microenvironment could lose their intrinsic functionalities such as target recognition ability, resulting in an ineffective cancer immunotherapy. Various manipulation techniques for decorating functional moieties onto cell surface and enhancing target recognition have been developed. A hydrophobic interaction-mediated ex-vivo cell surface engineering using lipid-based biomaterials could be a state-of-the-art engineering technique that could achieve high-efficiency cell surface modification by a single method without disturbance of intrinsic characteristics of cells. In this regard, this review provides design principles for the development of lipid-based biomaterials with a linear structure of lipid, polyethylene glycol, and functional group, strategies for the synthesis process, and their practical applications in biomedical engineering. Especially, we provide new insights into the development of a novel surface coating techniques for natural killer (NK) cells with engineering decoration of cancer targeting moieties on their cell surfaces. Among immune cells, NK cells are interesting cell population for substituting T cells because of their excellent safety and independent anticancer efficacy. Thus, optimal strategies to select cancer-type-specific targeting moieties and present them onto the surface of immune cells (especially, NK cells) using lipid-based biomaterials could provide additional tools to capture cancer cells for developing novel immune cell therapy products. Enhanced anticancer efficacies by surface-engineered NK cells have been demonstrated both in vitro and in vivo. Therefore, it could be speculated that recent progresses in cell surface modification technology via lipid-based biomaterials could strengthen immune surveillance and immune synapses for utilization in a next-generation cancer immunotherapy, beyond currently available genetic engineering tool such as chimeric antigen receptor-mediated immune cell modulation.

Aspirin-Mediated Reset of Preeclamptic Placental Stem Cell Transcriptome - Implication for Stabilized Placental Function

Preeclampsia (PE) is a pregnancy-specific disease, occurring in ~ 2-10% of all pregnancies. PE is associated with increased maternal and perinatal morbidity and mortality, hypertension, proteinuria, disrupted artery remodeling, placental ischemia and reperfusion, and inflammation. The mechanism of PE pathogenesis remains unresolved explaining limited treatment. Aspirin is used to reduce the risk of developing PE. This study investigated aspirin's effect on PE-derived placenta mesenchymal stem cells (P-MSCs). P-MSCs from chorionic membrane (CM), chorionic villi, membranes from the maternal and amniotic regions, and umbilical cord were similar in morphology, phenotype and multipotency. Since CM-derived P-MSCs could undergo long-term passages, the experimental studies were conducted with this source of P-MSCs. Aspirin (1 mM) induced significant functional and transcriptomic changes in PE-derived P-MSCs, similar to healthy P-MSCs. These include cell cycle quiescence, improved angiogenic pathways, and immune suppressor potential. The latter indicated that aspirin could induce an indirect program to mitigate PE-associated inflammation. As a mediator of activating the DNA repair program, aspirin increased p53, and upregulated genes within the basic excision repair pathway. The robust ability for P-MSCs to maintain its function with high dose aspirin contrasted bone marrow (M) MSCs, which differentiated with eventual senescence/aging with 100 fold less aspirin. This difference cautions how data from other MSC sources are extrapolated to evaluate PE pathogenesis. Dysfunction among P-MSCs in PE involves a network of multiple pathways that can be restored to an almost healthy functional P-MSC. The findings could lead to targeted treatment for PE.

TGFβ1-Pretreated Exosomes of Wharton Jelly Mesenchymal Stem Cell as a Therapeutic Strategy for Improving Liver Fibrosis

Background: Mesenchymal stem cells (MSCs) are the most promising tools for cell treatment and human tissue regeneration, e.g., in liver fibrosis. Mesenchymal stem cells repair tissue damage through paracrine mediators such as exosomes. Types and concentrations of inflammatory mediators, including transforming growth factor-beta (TGFβ1), in MSCs microenvironment can affect MSCs’ function and therapeutic potency. Objectives: This experimental study aimed to explore the effects of Wharton jelly MSCs (WJ-MSCs) exosomes on fibrotic gene expression and Smad2/3 phosphorylation (phospho-Smad2/3 (p-Smad2/3)). Moreover, we further investigated whether WJ-MSCs pretreatment with different concentrations of TGFβ1 changes the anti-fibrotic properties of their exosomes. Methods: After isolation from the umbilical cord, WJ-MSCs were characterized by observing differentiation and measuring surface biomarkers using flowcytometry. The WJ-MSC-derived exosomes were extracted and identified using transmission electron microscopy (TEM), dynamic light scattering (DLS), and western blotting. Real-time PCR and western blot for extracellular matrix (ECM) and p-Smad2/3 expression detection were used to investigate the effect of exosomes from untreated and TGFβ1-pretreated WJ-MSCs on activated hepatic stellate cells (HSCs). Results: Phospho-Smad2/3, α-smooth muscle actin (α-SMA), and collagen1α1 levels were enhanced following treatment with TGFβ1, whereas E-cadherin was decreased. However, the outcomes were reversed after treatment with WJ-MSC-derived exosomes. Exosomes from TGFβ1-pretreated WJ-MSCs induced a significant decrease in p-Smad2/3 levels in activated HSCs, accompanied by the upregulation of E-cadherin gene expression and downregulation of α-SMA and collagen1α1 when compared to untreated WJ-MSC-derived exosomes. The p-Smad2/3 proteins were significantly decreased (fold change: 0.23, P-value < 0.0001) after exposure to low-dose TGFβ1-pretreated WJ-MSC-derived exosomes (0.1 ng/mL), showing the best effect on activated HSCs. Conclusions: Exosomes derived from untreated WJ-MSCs could regress TGFβ-Smad2/3 signaling and the expression of fibrotic markers in activated LX-2 cells. However, these effects were significantly profound with applying exosomes derived from 0.1 ng/mL TGFβ-pretreated WJ-MSCs. We also observed the dose-response effects of TGFβ on WJ-MSCs-derived exosomes. Therefore, exosomes derived from TGFβ-pretreated WJ-MSCs may be critical in improving fibrosis and benefit liver fibrosis patients.

Epidermal Stem Cell in Wound Healing of Gliricidia sepium Leaves from Indonesia and the Philippines in Rats (Rattus norvegicus)

AIM: This study intended to investigate the regenerate wound, due to the ointment therapy containing Gliricidia sepium leaves that has potential-induced epidermal stem cells producing. It determined its effect on the expression of transforming growth factor-β1 (TGF-β1), Smad-3, β-catenin, LGR-6. MATERIALS AND METHODS: About 16 Wistar male rats aged approximately 2 months (150–200g) were used and were divided into four treatment groups (T1, positive control; T2, negative control; T3, wounds treated with G. sepium from Indonesia; and T4, wounds treated with G. sepium from the Philippines). The treatment of ointment was applied to the wound for 3 days. The expression of TGF-β1, Smad-3, β-catenin, and LGR-6 was observed by immunohistochemistry staining. RESULTS: G. sepium leaves significantly (p < 0.05) upregulated the expression of TGF-β1, Smad-3, β-catenin, and LGR-6 in the group treated with Indonesian G. sepium leaves were higher than that in the group treated with G. sepium leaves from the Philippines. CONCLUSIONS: Both leaves Varian contain flavonoids, saponins, and tannins, which act as producing epidermal stem cell agents to enhance the wound healing process. It can be concluded that both Gl. sepium Varian Indonesia and the Philippines have a potential effect on wound healing.

Strategies to improve regenerative potential of mesenchymal stem cells

In the last few decades, stem cell-based therapies have gained attention worldwide for various diseases and disorders. Adult stem cells, particularly mesenchymal stem cells (MSCs), are preferred due to their significant regenerative potential in cellular therapies and are currently involved in hundreds of clinical trials. Although MSCs have high self-renewal as well as differentiation potential, such abilities are compromised with “advanced age” and “disease status” of the donor. Similarly, cell-based therapies require high cell number for clinical applications that often require in vitro expansion of cells. It is pertinent to note that aged individuals are the main segment of population for stem cell-based therapies, however; autologous use of stem cells for such patients (aged and diseased) does not seem to give optimal results due to their compromised potential. In vitro expansion to obtain large numbers of cells also negatively affects the regenerative potential of MSCs. It is therefore essential to improve the regenerative potential of stem cells compromised due to “in vitro expansion”, “donor age” and “donor disease status” for their successful autologous use. The current review has been organized to address the age and disease depleted function of resident adult stem cells, and the strategies to improve their potential. To combat the problem of decline in the regenerative potential of cells, this review focuses on the strategies that manipulate the cell environment such as hypoxia, heat shock, caloric restriction and preconditioning with different factors.

MSCs and their exosomes: a rapidly evolving approach in the context of cutaneous wounds therapy

Currently, mesenchymal stem/stromal stem cell (MSC) therapy has become a promising option for accelerating cutaneous wound healing. In vivo reports have outlined the robust competences of MSCs to offer a solid milieu by inhibition of inflammatory reactions, which in turn, enables skin regeneration. Further, due to their great potential to stimulate angiogenesis and also facilitate matrix remodeling, MSCs hold substantial potential as future therapeutic strategies in this context. The MSCs-induced wound healing is thought to mainly rely on the secretion of a myriad of paracrine factors in addition to their direct differentiation to skin-resident cells. Besides, MSCs-derived exosomes as nanoscale and closed membrane vesicles have recently been suggested as an effective and cell-free approach to support skin regeneration, circumventing the concerns respecting direct application of MSCs. The MSCs-derived exosomes comprise molecular components including lipid, proteins, DNA, microRNA, and also mRNA, which target molecular pathways and also biological activities in recipient cells (e.g., endothelial cell, keratinocyte, and fibroblast). The secreted exosome modifies macrophage activation, stimulates angiogenesis, and instigates keratinocytes and dermal fibroblast proliferations as well as migrations concurrently regulate inherent potential of myofibroblast for adjustment of turnover of the ECM. In the present review, we will focus on the recent findings concerning the application of MSCs and their derivative exosome to support wound healing and skin regeneration, with special focus on last decade in vivo reports.

Mesenchymal Stem Cell Therapy: Hope for Patients With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Although previous studies have demonstrated that SLE is related to the imbalance of cells in the immune system, including B cells, T cells, and dendritic cells, etc., the mechanisms underlying SLE pathogenesis remain unclear. Therefore, effective and low side-effect therapies for SLE are lacking. Recently, mesenchymal stem cell (MSC) therapy for autoimmune diseases, particularly SLE, has gained increasing attention. This therapy can improve the signs and symptoms of refractory SLE by promoting the proliferation of Th2 and Treg cells and inhibiting the activity of Th1, Th17, and B cells, etc. However, MSC therapy is also reported ineffective in some patients with SLE, which may be related to MSC- or patient-derived factors. Therefore, the therapeutic effects of MSCs should be further confirmed. This review summarizes the status of MSC therapy in refractory SLE treatment and potential reasons for the ineffectiveness of MSC therapy from three perspectives. We propose various MSC modification methods that may be beneficial in enhancing the immunosuppression of MSCs in SLE. However, their safety and protective effects in patients with SLE still need to be confirmed by further experimental and clinical evidence.

Glibenclamide Nanocrystal-Loaded Bioactive Polymeric Scaffolds for Skin Regeneration: In Vitro Characterization and Preclinical Evaluation

Skin restoration following full-thickness injury poses significant clinical challenges including inflammation and scarring. Medicated scaffolds formulated from natural bioactive polymers present an attractive platform for promoting wound healing. Glibenclamide was formulated in collagen/chitosan composite scaffolds to fulfill this aim. Glibenclamide was forged into nanocrystals with optimized colloidal properties (particle size of 352.2 nm, and polydispersity index of 0.29) using Kolliphor as a stabilizer to allow loading into the hydrophilic polymeric matrix. Scaffolds were prepared by the freeze drying method using different total polymer contents (3-6%) and collagen/chitosan ratios (0.25-2). A total polymer content of 3% at a collagen/chitosan ratio of 2:1 (SCGL3-2) was selected based on the results of in vitro characterization including the swelling index (1095.21), porosity (94.08%), mechanical strength, rate of degradation and in vitro drug release. SCGL3-2 was shown to be hemocompatible based on the results of protein binding, blood clotting and percentage hemolysis assays. In vitro cell culture studies on HSF cells demonstrated the biocompatibility of nanocrystals and SCGL3-2. In vivo studies on a rat model of a full-thickness wound presented rapid closure with enhanced histological and immunohistochemical parameters, revealing the success of the scaffold in reducing inflammation and promoting wound healing without scar formation. Hence, SCGL3-2 could be considered a potential dermal substitute for skin regeneration.

Antioxidant pretreatment enhances umbilical cord derived stem cells survival in response to thermal stress in vitro

Aim: Pretreatment of stem cells with antioxidants accelerates their ability to counter oxidative stress and is associated with the overall therapeutic outcome of their transplantation. Material & methods: Wharton Jelly derived mesenchymal stem cells (WJMSCs) were cultured and pretreated with various doses of antioxidants; Vitamin C (Vit C), Vitamin E (Vit E), Vitamin D3 (Vit D3) and their Cocktail, followed by exposure to in vitro heat injury. Assessment of WJMSCs survival, paracrine release, in vitro wound healing and expression of angiogenic and survival markers was conducted. Results: The results displayed an enhanced survival of WJMSCs especially in the case of Cocktail priming. Conclusion: Our data suggest that antioxidant pretreatment of WJMSCs strengthens the endurance of the cells, within stress conditions.

Reactive Oxygen Species (ROS), Intimal Thickening, and Subclinical Atherosclerotic Disease

Arteriosclerosis causes significant morbidity and mortality worldwide. Central to this process is the development of subclinical non-atherosclerotic intimal lesions before the appearance of pathologic intimal thickening and advanced atherosclerotic plaques. Intimal thickening is associated with several risk factors, including oxidative stress due to reactive oxygen species (ROS), inflammatory cytokines and lipid. The main ROS producing systems in-vivo are reduced nicotinamide dinucleotide phosphate (NADPH) oxidase (NOX). ROS effects are context specific. Exogenous ROS induces apoptosis and senescence, whereas intracellular ROS promotes stem cell differentiation, proliferation, and migration. Lineage tracing studies using murine models of subclinical atherosclerosis have revealed the contributory role of medial smooth muscle cells (SMCs), resident vascular stem cells, circulating bone-marrow progenitors and endothelial cells that undergo endothelial-mesenchymal-transition (EndMT). This review will address the putative physiological and patho-physiological roles of ROS in controlling vascular cell fate and ROS contribution to vascular regeneration and disease progression.

A review on different methods to increase the efficiency of mesenchymal stem cell-based wound therapy

Mesenchymal stem cells (MSCs) accelerate wound healing but the harsh environment of wound site limits the engraftment, retention, and survival rate of transplanted cells. There are multiple approaches that amplify the therapeutic potential of MSCs. The MSCs derived from medical waste material, provide comparable regenerative abilities compared to traditional sources. The application of different scaffolds increases MSC delivery and migration into the wound. The spheroid culture of MSC increases the paracrine effects of the entrapped cells and the secretion of pro-angiogenic and anti-inflammatory cytokines. The MSC pretreating and preconditioning enhances the cell migration, proliferation, and survival rate, which lead to higher angiogenesis, re-epithelialization, wound closure, and granulation tissue formation. Moreover, genetic modification has been performed in order to increase MSC angiogenesis, differentiation potential, as well as the cell life span. Herein, we review the results of aforementioned approaches and provide information accommodating to the continued development of MSC-based wound therapy in the future.

Mesenchymal Stem Cell Migration and Tissue Repair

Mesenchymal stem cells (MSCs) are multilineage cells with the ability to self-renew and differentiate into a variety of cell types, which play key roles in tissue healing and regenerative medicine. Bone marrow-derived mesenchymal stem cells (BMSCs) are the most frequently used stem cells in cell therapy and tissue engineering. However, it is prerequisite for BMSCs to mobilize from bone marrow and migrate into injured tissues during the healing process, through peripheral circulation. The migration of BMSCs is regulated by mechanical and chemical factors in this trafficking process. In this paper, we review the effects of several main regulatory factors on BMSC migration and its underlying mechanism; discuss two critical roles of BMSCs-namely, directed differentiation and the paracrine function-in tissue repair; and provide insight into the relationship between BMSC migration and tissue repair, which may provide a better guide for clinical applications in tissue repair through the efficient regulation of BMSC migration.

Proteomic Identification and Time-Course Monitoring of Secreted Proteins During Expansion of Human Mesenchymal Stem/Stromal in Stirred-Tank Bioreactor

The therapeutic potential of mesenchymal stem/stromal cells (MSC) is widely recognized for the treatment of several diseases, including acute graft-vs.-host disease (GVHD), hematological malignancies, cardiovascular, bone, and cartilage diseases. More recently, this therapeutic efficacy has been attributed to the bioactive molecules that these cells secrete (secretome), now being referred as medicinal signaling cells. This fact raises the opportunity of therapeutically using MSC-derived soluble factors rather than cells themselves, enabling their translation into the clinic. Indeed, many clinical trials are now studying the effects of MSC-secretome in the context of cell-free therapy. MSC secretome profile varies between donors, source, and culture conditions, making their therapeutic use very challenging. Therefore, identifying these soluble proteins and evaluating their production in a reproducible and scalable manner is even more relevant. In this work, we analyzed the global profile of proteins secreted by umbilical cord matrix (UCM) derived-MSC in static conditions by using mass spectrometry, enabling the identification of thousands of proteins. Afterwards, relevant proteins were chosen and monitored in the supernatant of a fully-controllable, closed and scalable system (bioreactor) by using multiple reaction monitoring (MRM) mass spectrometric technique in a time-dependent manner. The results showed that the majority of interesting proteins were enriched through time in culture, with the last day of culture being the ideal time for supernatant collection. The use of this regenerative "soup," which is frequently discarded, could represent a step toward a safe, robust and reproducible cell-free product to be used in the medical therapeutic field. The future use of chemically defined culture-media will certainly facilitate secretome production according to Good Manufacturing Practice (GMP) standards.

Metabolic Syndrome and Skin Diseases

The increasing prevalence of Metabolic syndrome (MetS) is a worldwide health problem, and the association between MetS and skin diseases has recently attracted growing attention. In this review, we summarize the associations between MetS and skin diseases, such as psoriasis, acne vulgaris, hidradenitis suppurativa, androgenetic alopecia, acanthosis nigricans, and atopic dermatitis. To discuss the potential common mechanisms underlying MetS and skin diseases, we focus on insulin signaling and insulin resistance, as well as chronic inflammation including adipokines and proinflammatory cytokines related to molecular mechanisms. A better understanding of the relationship between MetS and skin diseases contributes to early diagnosis and prevention, as well as providing clues for developing novel therapeutic strategies.

Senescence of bone marrow-derived mesenchymal stem cells from patients with idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease for which age is the most important risk factor. Different mechanisms associated with aging, including stem cell dysfunction, have been described to participate in the pathophysiology of IPF. We observed an extrapulmonary effect associated with IPF: increase in cell senescence of bone marrow-derived mesenchymal stem cells (B-MSCs).

Methods

B-MSCs were obtained from vertebral bodies procured from IPF patients and age-matched normal controls. Cell senescence was determined by cell proliferation and expression of markers of cell senescence p16^INK4A, p21, and β-galactosidase activity. Mitochondrial function and DNA damage were measured. Paracrine induction of senescence and profibrotic responses were analyzed in vitro using human lung fibroblasts. The reparative capacity of B-MSCs was examined in vivo using the bleomycin-induced lung fibrosis model.

Results

In our study, we demonstrate for the first time that B-MSCs from IPF patients are senescent with significant differences in mitochondrial function, with accumulation of DNA damage resulting in defects in critical cell functions when compared with age-matched controls. Senescent IPF B-MSCs have the capability of paracrine senescence by inducing senescence in normal-aged fibroblasts, suggesting a possible link between senescent B-MSCs and the late onset of the disease. IPF B-MSCs also showed a diminished capacity to migrate and were less effective in preventing fibrotic changes observed in mice after bleomycin-induced injury, increasing illness severity and proinflammatory responses.

Conclusions

We describe extrapulmonary alterations in B-MSCs from IPF patients. The consequences of having senescent B-MSCs are not completely understood, but the decrease in their ability to respond to normal activation and the risk of having a negative impact on the local niche by inducing inflammation and senescence in the neighboring cells suggests a new link between B-MSC and the onset of the disease.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0970-6) contains supplementary material, which is available to authorized users.

Regenerative potential of partially differentiated mesenchymal stromal cells in a mouse model of a full-thickness skin wound

Mesenchymal stromal cells (MSCs, known as mesenchymal stem cells) are considered to be a promising therapeutic tool for many diseases. But it is still unclear which cells are more efficient and safe for wound healing and tissue regeneration for clinical applications: undifferentiated, partially differentiated stem cells or differentiated cells. In this study, we modified MSCs with keratinocyte-conditioned medium (KCM) and examined MSCs, partially differentiated MSCs (PMSCs) and differentiated cell migration, accumulation in the wounded area as well as cell regenerative efficiency in a full-thickness skin wound model. In addition to that, the impact of intradermal and intravenous cell delivery methods of wound healing was evaluated. C57BL/6J mouse compact bone MSCs were treated with a KCM for 14 days. Flow cytometry analysis showed the appearance of keratinocyte surface markers which were absent in MSCs, whereas the specific markers for MSCs were lost. Cells were injected either intravenously or intradermally in C57BL/6J mice. Wound closure, cell migration and accumulation in the wounded area were further analysed. Wound healing was assessed by the rate of wound closure and by histological evaluation. Cells were monitored using optical imaging. We demonstrated that PMSCs showed morphology similar to keratinocyte cells, had enhanced migration and increased survival at the site of injury. PMSCs had a beneficial effect on wound healing and tissue regeneration. This effect was reinforced when these cells were injected intravenously. Due to their partial differentiation status, we assume that PMSCs can differentiate more rapidly into epidermal cell lineages thus causing faster and qualitatively improved wound healing.

iTRAQ-Based Proteomic Analysis Exploring the Influence of Hypoxia on the Proteome of Dental Pulp Stem Cells under 3D Culture

Hypoxic preconditioning is commonly applied to enhance mesenchymal stem cells (MSCs) therapeutic effect before transplantation. Elucidating the effect of hypoxic preconditioning would be beneficial for improved application. However, the influence of hypoxia on dental tissue derived MSCs cultured in 3D was unknown. Thus, the present study is to investigate gene expression and proteome of dental pulp stem cells (DPSCs) after hypoxic preconditioning. DPSCs were isolated, cultured in a 3D system under the normoxic and hypoxic conditions. The gene expression was examined with reverse transcription polymerase chain reaction, and the proteome was analyzed using iTRAQ-based mass spectrometry. The expressions of HIF-1α, VEGFA, KDR at mRNA level was upregulated while BMP-2 was downregulated. Two thousand one hundred and fifteen proteins were identified and 57 proteins exhibited significant differences after hypoxic preconditioning (30 up-regulated, 27 down-regulated). Bioinformatic analysis revealed the majority of up-regulated proteins are involved in cellular process, angiogenesis, protein binding and transport, regulation of response to stimulus, metabolic processes, and immune response. Increased IL-6 and decreased TGF-1β protein expression under hypoxic condition were verified by ELISA. Hypoxic preconditioning partly affected the gene and protein expression in DPSCs under 3D culture and may enhance the efficacy of MSCs transplantation.

Protective effects of mesenchymal stem cell cond tional medium against inflammatory injury on human gingival fibroblast

Mesenchymal stem cells (MSCs) alleviate oxidative stress in kidney, lung and heart by secreting bioactive factors. Human gingival fibroblasts (HGFs) are important for repairing periodontal tissues. This study observed protective effects of MSCs conditional medium (MSCCM) on HGFs against inflammatory injury, to investigate anti-inflammatory function and mechanism of MSCCM on HGFs. Primary cultured HGFs were identified for sources by immunohistochemistry (IHC)-SP assay. In vitro cultured MSCs were extracted for MSCCM, which was used to pre-treat HGFs with inflammatory induction by 10 μg/L IL-6 or TNF-α for 4 h. ELISA quantified transforming growth factor (TGF)-β level in the supernatant, and superoxide dismutase (SOD) plus malondialdehyde (MDA) levels were measured by colorimetry. RT-PCR measured keratocyte growth factor (KGF) mRNA expression, and flow cytometry or Western blot measured apoptosis or Caspase-3 expression in HGFs, respectively. Compared to control group, MSCCM treatment group showed no significant change of SOD, MDA, TGF-β level, cell apoptosis, KGF mRNA or Caspase-3 expression (P>0.05). Inflammation treatment elevated all those indexes but decreased SOD (P<0.05). Compared to model group, MSCCM treatment further decreased these factors but increased SOD level (P<0.05). No significant difference was found between IL-6 and TNF-α treated cells. MSCCM can partially inhibit IL-6 induced inflammatory injury of HGFs via suppressing Caspase-3 and KGF expression.

Platelet "first responders" in wound response, cancer, and metastasis

Platelets serve as "first responders" during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity, and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation, and wound biology that leads to sterilization, tissue repair, and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression, and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation, and metastasis. This process, along with the hypercoagulable states associated with malignancy, is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the "first responder" role of platelets during diverse physiologic stresses provide a useful therapeutic target that deserves further exploration.