Mesenchymal stem cells

Mesenchymal stem cells modulate breast cancer progression through their secretome by downregulating ten-eleven translocation 1

Mesenchymal stem cells (MSCs) have emerged as crucial players within the tumor microenvironment (TME), contributing through their paracrine secretome. Depending on the context, the MSC-derived secretome can either support or inhibit tumor growth. This study investigates the role of MSC-derived secretome in modulating breast cancer (BC) cell behavior, with a focus on ten-eleven translocation 1 (TET1), a DNA demethylase with known oncogenic properties in triple-negative breast cancer (TNBC). We first isolated and characterized human bone marrow-derived MSCs, and then assessed the impact of their secretome on BC cells. Treatment with the MSC-derived secretome significantly inhibited the proliferation and migration of both MDA-MB-231 and MCF-7 BC cell lines, resulting in reduced cell viability and migration rates compared to control cells. Western blot analyses revealed downregulation of Cyclin D1 and c-Myc, along with decreased expression of N-cadherin and increased expression of E-cadherin, indicating potential inhibition of the epithelial-to-mesenchymal transition. Differential gene expression analyses highlighted TET1 as significantly upregulated in TNBC tissues compared to normal samples. Further experiments confirmed that the MSC-derived secretome downregulated TET1 expression in BC cells, as evidenced by RT-qPCR and western blot analyses. To explore TET1's functional role, we silenced TET1 with siRNAs, observing cell cycle arrest and enhanced apoptosis-effects that mirrored those seen with MSC-secretome treatment. Notably, TET1 knockdown also increased MDA-MB-231 cell sensitivity to cisplatin, suggesting a role for TET1 in chemoresistance. These findings provide insight into the ability of MSCs to modulate BC cell progression through their secretome, highlighting the involvement of TET1 downregulation in inhibiting BC cell progression and enhancing cisplatin chemosensitivity. The MSC-derived secretome thus holds promise as an innovative, cell-free therapeutic approach in BC treatment.

Mesenchymal stromal cells alleviate APAP-induced liver injury via extracellular vesicle-mediated regulation of the miR-186-5p/CXCL1 axis

BACKGROUND

Acetaminophen (APAP) overdose is a significant cause of drug-induced liver injury (DILI). N-acetylcysteine (NAC) is the first-line agent used in the clinic. However, it rarely benefits patients with advanced APAP toxicity. Mesenchymal stromal cells (MSCs) have demonstrated potential in treating DILI. However, the specific mechanism by which MSCs protect against APAP-induced liver injury remains unclear.

METHODS

APAP was injected intraperitoneally to induce a liver injury model. We then detected histopathology, biochemical indices, and inflammatory cytokine levels to assess the efficacy of MSCs and MSC extracellular vesicles (MSC-EVs). Flow cytometry was performed to reveal the immunoregulatory effects of MSCs and MSC-EVs on the neutrophils. RNA sequencing (RNA-Seq) of liver tissues was used to identify critical target genes for MSC treatment.

RESULTS

MSC and MSC-EV treatment effectively alleviated APAP-induced liver injury and inhibited neutrophil infiltration. RNA-Seq analysis and ELISA data indicated that C-X-C motif chemokine 1 (CXCL1), a chemoattractant for neutrophils, was a key molecule in the MSC-mediated amelioration of APAP-induced liver damage. In addition, neutralization of CXCL1 reduced APAP-induced liver damage, which was accompanied by decreased neutrophil infiltration. Importantly, we verified that MSC-EV-derived miR-186-5p directly binds to the 3'-UTR of Cxcl1 to inhibit its expression in hepatocytes. The agomir miR-186-5p showed excellent potential for the treatment of DILI.

CONCLUSIONS

Our findings suggest that MSCs and MSC-EVs are an effective approach to mitigate DILI. Targeting the miR-186-5p/CXCL1 axis is a promising approach to improve the efficacy of MSCs and MSC-EVs in the treatment of DILI.

Hypoxia and Normoxia Preconditioned Olfactory Stem Cells Against Noise-Induced Hearing Loss

OBJECTIVE

Noise-induced hearing loss is one of the leading causes of permanent hearing loss in the adult population. In this experimental study, the authors aimed to investigate the effectiveness of hypoxia and normoxia preconditioned olfactory stem cells against noise trauma.

METHODS

Twenty-seven female guinea pigs were enrolled. Two guinea pigs were sacrificed for harvesting olfactory tissue and 1 for examining the architecture of the normal cochlea. The remaining 24 guinea pigs were exposed to noise trauma for 1 day and then randomly divided into 3 groups: intracochlear injection of (i) normoxic olfactory stem cells, (ii) hypoxic olfactory stem cells, and (iii) physiological serum. Auditory brainstem response (ABR) measurement was performed before and 2 weeks after noise trauma and weekly for 3 weeks following intracochlear injection. Both click and 16 kHz tone-burst stimuli were used for detection of ABR.

RESULTS

No significant difference was noted between the groups before and 2 weeks after noise trauma. ABR thresholds detected after intracochlear injections were significantly higher in the control group compared with stem cell groups. However, no significant difference was detected between the stem cell groups. Fluourescence microscopy revealed better engraftment for hypoxic stem cells. Light and electron microscopy examinations were consistent with predominant degenerative findings in the control group, whereas normoxic group had more similar findings with normal cochlea compared with hypoxic group.

CONCLUSION

Olfactory stem cells were demonstrated to have the potential to have beneficial effects on noise trauma.

Advances and clinical challenges of mesenchymal stem cell therapy

In recent years, cell therapy has provided desirable properties for promising new drugs. Mesenchymal stem cells are promising candidates for developing genetic engineering and drug delivery strategies due to their inherent properties, including immune regulation, homing ability and tumor tropism. The therapeutic potential of mesenchymal stem cells is being investigated for cancer therapy, inflammatory and fibrotic diseases, among others. Mesenchymal stem cells are attractive cellular carriers for synthetic nanoparticles for drug delivery due to their inherent homing ability. In this review, we comprehensively discuss the various genetic and non-genetic strategies of mesenchymal stem cells and their derivatives in drug delivery, tumor therapy, immune regulation, tissue regeneration and other fields. In addition, we discuss the current limitations of stem cell therapy and the challenges in clinical translation, aiming to identify important development areas and potential future directions.

Smart/stimuli-responsive chitosan/gelatin and other polymeric macromolecules natural hydrogels vs. synthetic hydrogels systems for brain tissue engineering: A state-of-the-art review

Currently, there are no viable curative treatments that can enhance the central nervous system's (CNS) recovery from trauma or illness. Bioengineered injectable smart/stimuli-responsive hydrogels (SSRHs) that mirror the intricacy of the CNS milieu and architecture have been suggested as a way to get around these restrictions in combination with medication and cell therapy. Additionally, the right biophysical and pharmacological stimuli are required to boost meaningful CNS regeneration. Recent research has focused heavily on developing SSRHs as cutting-edge delivery systems that can direct the regeneration of brain tissue. In the present article, we have discussed the pathology of brain injuries, and the applicable strategies employed to regenerate the brain tissues. Moreover, the most promising SSRHs for neural tissue engineering (TE) including alginate (Alg.), hyaluronic acid (HA), chitosan (CH), gelatin, and collagen are used in natural polymer-based hydrogels and thoroughly discussed in this review. The ability of these hydrogels to distribute bioactive substances or cells in response to internal and external stimuli is highlighted with particular attention. In addition, this article provides a summary of the most cutting-edge techniques for CNS recovery employing SSRHs for several neurodegenerative diseases.

Stem cell therapy for hepatocellular carcinoma and end-stage liver disease

Hepatocellular carcinoma (HCC) is a major health problem worldwide, especially for patients who are suffering from end-stage liver disease (ESLD). The ESLD is considered a great challenge for clinicians due to the limited chance for liver transplantation, which is the only curative treatment for those patients. Stem cell-based therapy as a part of regenerative medicine represents a promising application for ESLD patients. Many clinical trials were performed to assess the utility of bone marrow-derived stem cells as a potential therapy for patients with liver diseases. The aim of the present study is to present and review the various types of stem cell-based therapy, including the mesenchymal stem cells (MSCs), BM-derived mononuclear cells (BM-MNCs), CD34 + hematopoietic stem cells (HSCs), induced pluripotent stem cells (iPSCs), and cancer stem cells.Though this type of therapy achieved promising results for the treatment of ESLD, however still there is a confounding data regarding its clinical application. A large body of evidence is highly required to evaluate the stem cell-based therapy after long-term follow-up, with respect to the incidence of toxicity, immunogenicity, and tumorigenesis that developed in many patients.

Potential Application of Orofacial MSCs in Tissue Engineering Nerve Guidance for Peripheral Nerve Injury Repair

Injury to the peripheral nerve causes potential loss of sensory and motor functions, and peripheral nerve repair (PNR) remains a challenging endeavor. The current clinical methods of nerve repair, such as direct suture, autografts, and acellular nerve grafts (ANGs), exhibit their respective disadvantages like nerve tension, donor site morbidity, size mismatch, and immunogenicity. Even though commercially available nerve guidance conduits (NGCs) have demonstrated some clinical successes, the overall clinical outcome is still suboptimal, especially for nerve injuries with a large gap (≥ 3 cm) due to the lack of biologics. In the last two decades, the combination of advanced tissue engineering technologies, stem cell biology, and biomaterial science has significantly advanced the generation of a new generation of NGCs incorporated with biological factors or supportive cells, including mesenchymal stem cells (MSCs), which hold great promise to enhance peripheral nerve repair/regeneration (PNR). Orofacial MSCs are emerging as a unique source of MSCs for PNR due to their neural crest-origin and easy accessibility. In this narrative review, we have provided an update on the pathophysiology of peripheral nerve injury and the properties and biological functions of orofacial MSCs. Then we have highlighted the application of orofacial MSCs in tissue engineering nerve guidance for PNR in various preclinical models and the potential challenges and future directions in this field.

Extracellular Vesicles as a Translational Approach for the Treatment of COVID-19 Disease: An Updated Overview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic in the years 2020-2022. With a high prevalence, an easy route of transmission, and a long incubation time, SARS-CoV-2 spread quickly and affected public health and socioeconomic conditions. Several points need to be elucidated about its mechanisms of infection, in particular, its capability to evade the immune system and escape from neutralizing antibodies. Extracellular vesicles (EVs) are phospholipid bilayer-delimited particles that are involved in cell-to-cell communication; they contain biological information such as miRNAs, proteins, nucleic acids, and viral components. Abundantly released from biological fluids, their dimensions are highly variable, which are used to divide them into exosomes (40 to 150 nm), microvesicles (40 to 10,000 nm), and apoptotic bodies (100-5000 nm). EVs are involved in many physiological and pathological processes. In this article, we report the latest evidence about EVs' roles in viral infections, focusing on the dual role of exosomes in promoting and inhibiting SARS-CoV-2 infection. The involvement of mesenchymal stromal/stem cells (MSCs) and MSC-derived EVs in COVID-19 treatment, such as the use of translational exosomes as a diagnostical/therapeutic approach, is also investigated. These elucidations could be useful to better direct the discovery of future diagnostical tools and new exosome-derived COVID-19 biomarkers, which can help achieve optimal therapeutic interventions and implement future vaccine strategies.

From Interaction to Intervention: How Mesenchymal Stem Cells Affect and Target Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expressions, making targeted therapies ineffective. Mesenchymal stem cells (MSCs) have emerged as a promising approach for TNBC treatment by modulating the tumor microenvironment (TME) and interacting with cancer cells. This review aims to comprehensively overview the role of MSCs in TNBC treatment, including their mechanisms of action and application strategies. We analyze the interactions between MSC and TNBC cells, including the impact of MSCs on TNBC cell proliferation, migration, invasion, metastasis, angiogenesis, and drug resistance, along with the signaling pathways and molecular mechanisms involved. We also explore the impact of MSCs on other components of the TME, such as immune and stromal cells, and the underlying mechanisms. The review discusses the application strategies of MSCs in TNBC treatment, including their use as cell or drug carriers and the advantages and limitations of different types and sources of MSCs in terms of safety and efficacy. Finally, we discuss the challenges and prospects of MSCs in TNBC treatment and propose potential solutions or improvement methods. Overall, this review provides valuable insights into the potential of MSCs as a novel therapeutic approach for TNBC treatment.

CD44 mediates hyaluronan to promote the differentiation of human amniotic mesenchymal stem cells into chondrocytes

OBJECTIVES

CD44 is the major receptor for hyaluronan (HA), but its effect on HA-induced differentiation of human amnion mesenchymal stem cells into chondrocytes is unclear. This study aimed to investigate the effects and mechanisms of CD44 in HA-induced chondrogenesis.

METHODS

Immunocytochemistry and toluidine blue staining were used to assess the secretion of type II collagen and aggrecan, respectively. qRT-PCR and western blotting were performed to evaluate the expression of key genes and proteins.

RESULTS

The expression of aggrecan and type II collagen was downregulated after using the anti-CD44 antibody (A3D8). The transcriptional levels of chondrocytes‑associated genes SRY‑box transcription factor 9, aggrecan, and collagen type II alpha 1 chain were also decreased. Thus, CD44 may mediate HA-induced differentiation of hAMSCs into chondrocytes. Further investigation indicated that expression of phosphorylated (p)‑Erk1/2 and p‑Smad2 decreased following CD44 inhibition. The changes in the expression of p-Erk1/2 and p-Smad2 were consistent after using the ERK1/2 inhibitor (U0126) and agonist (EGF), respectively. After administering the p-Smad2 inhibitor, the expression levels of p-ERK1/2 and p-Smad2 appeared downregulated. The results showed crosstalk between Erk1/2 and Smad2. Moreover, inhibition of p-Erk1/2 and p-Smad2 significantly reduced the accumulation of aggrecan and type II collagen.

CONCLUSION

These data indicate that CD44 mediates HA-induced differentiation of hAMSCs into chondrocytes by regulating Erk1/2 and Smad2 signaling.

In Vitro Chondrogenic Differentiation of Human Adipose-Derived Stem Cells by Diacerein

Background

Tissue engineering is the application system that tries to restore damaged tissues by different approaches, such as cellular therapy, application of cell differential factors, and various materials. One of the important goals in tissue engineering is to guide stem cells directly to the desired tissue, and researchers tried to utilize different molecules as effective factors to improve this technique.

Objectives

This study aims to demonstrate the effects of diacerein, a slow-acting drug for the treatment of osteoarthritis, on mesenchymal stem cell proliferation and evaluate its potential in the chondrogenesis process.

Methods

Stem cells were isolated from adipose tissue, characterized by flow cytometry, and cells were treated with 10-5M diacerein for three weeks. Chondrogenic gene expression of SOX9, COL2A1, ACAN, and TGFB1 were analyzed by qRT-PCR and immunocytochemistry techniques.

Results

Our results showed that diacerein increased the expression of the following genes involved in chondrogenesis: SOX9 (2.9-fold, P < 0.00), COL2A1 (2.2-fold, P < 0.00), ACAN (2.7-fold, P < 0.00), and TGFB1 (2.6-fold, P < 0.00). Immunocytochemistry results also showed increased production of collagen type II as the main protein marker for chondrocytes.

Conclusions

We observed that diacerein alone could initiate and enhance chondrogenesis, and it can be used as a differentiation factor for stem cells to chondrocyte besides its ability to inhibit IL-1β. Knowing the actual function of diacerein, it could be a good candidate for the treatment of osteoarthritis.

Human nasal olfactory stem cells, purified as advanced therapy medicinal products, improve neuronal differentiation

BACKGROUND

Olfactory ecto-mesenchymal stem cells (OE-MSC) are mesenchymal stem cells derived from the lamina propria of the nasal mucosa. They display neurogenic and immunomodulatory properties and were shown to induce recovery in animal models of spinal cord trauma, hearing loss, Parkinsons's disease, amnesia, and peripheral nerve injury. As a step toward clinical practice, we sought to (i) devise a culture protocol that meets the requirements set by human health agencies and (ii) assess the efficacy of stem cells on neuron differentiation.

METHODS

Nasal olfactory mucosa biopsies from three donors were used to design and validate the good manufacturing process for purifying stem cells. All processes and procedures were performed by expert staff from the cell therapy laboratory of the public hospital of Marseille (AP-HM), according to aseptic handling manipulations. Premises, materials and air were kept clean at all times to avoid cross-contamination, accidents, or even fatalities. Purified stem cells were cultivated for 24 or 48 h and conditioned media were collected before being added to the culture medium of the neuroblastoma cell line Neuro2a.

RESULTS

Compared to the explant culture-based protocol, enzymatic digestion provides higher cell numbers more rapidly and is less prone to contamination. The use of platelet lysate in place of fetal calf serum is effective in promoting higher cell proliferation (the percentage of CFU-F progenitors is 15.5%), with the optimal percentage of platelet lysate being 10%. Cultured OE-MSCs do not show chromosomal rearrangement and, as expected, express the usual phenotypic markers of mesenchymal stem cells. When incorporated in standard culture medium, the conditioned medium of purified OE-MSCs promotes cell differentiation of Neuro2a neuroblastoma cells.

CONCLUSION

We developed a safer and more efficient manufacturing process for clinical grade olfactory stem cells. With this protocol, human OE-MSCs will soon be used in a Phase I clinical based on their autologous transplantation in digital nerves with a neglected injury. However, further studies are required to unveil the underlying mechanisms of action.

Global scientific trends on the immunomodulation of mesenchymal stem cells in the 21st century: A bibliometric and visualized analysis

Background

Since the discovery of the immunomodulatory functions of mesenchymal stem cells (MSCs), their application in immunomodulation has attracted considerable attention, and an increasing number of studies have been conducted worldwide. Our research aimed to investigate the global status and trends in this field.

Methods

Publications on the immunomodulatory functions of MSCs from 1 January 2000 to 7 March 2022 were retrieved from the Web of Science Core Collection. The data were studied and indexed using the bibliometric methodology. Visualization analysis, co-authorship, co-occurrence analysis, and publication trends in MSC immunomodulation were conducted using the VOSviewer software.

Results

In total, 4,227 papers were included in the study. The number of publications and research interests has significantly increased globally. China published the highest number of related articles, while the US published articles with the highest number of citations. Stem Cell Research & Therapy had the highest number of publications. Sun Yat-sen University, Shanghai Jiao Tong University, Harvard University, and Seoul National University were the most contributive institutions. Furthermore, the studies were divided into four research hotspots for MSC immunomodulation: MSC immunomodulation in regenerative medicine, the effects and mechanisms of MSC immunomodulation, MSC therapy for immune diseases, and the cell source of MSCs.

Conclusion

This study indicates that the number of publications on MSC immunomodulation will increase in the future, and MSC immunomodulation mechanisms and clinical applications of MSC immunotherapy should be the next hotspots in this research field.

An Overview of Current Research on Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Bibliometric Analysis From 2009 to 2021

Background: Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are important mediators of intercellular communication and participate in numerous physiological and pathological processes in the body. This study aims to introduce the research status, analyze the research hotspots, and predict the development trend through bibliometric analysis of MSC-EVs.

Methods: We searched all relevant literature on MSC-EVs from 2009 to 2021 in the Web of Science. R-bibliometrix, VOSviewer, and CiteSpace software were used to visualize the quantitative analysis of the published literature, including co-authorship, co-occurrence, citation, and co-citation, to provide objective presentation and predictions in the field.

Results: A total of 1595 articles and reviews on MSC-EVs published between 2009 and 2021 were identified. The annual publication outputs increased at an exponential rate, reaching as high as 555 publications in 2021. China contributed the most publications (n = 899, 56.36%) and had the most citations (n = 24,210). The United States had the strongest intensity of cooperation in this field. Shanghai Jiao Tong University had the maximum number of publications (n = 79). In terms of the number of publications and co-citations, the journal of Stem cell research & therapy ranked first. Camussi G was the most productive and most cited author. The top three themes in the research area were cell biology, research experimental medicine, and biochemistry molecular biology. Keyword co-occurrence and co-citation clustering analysis revealed that studies of MSC-EVs covered cellular origin (bone marrow mesenchymal stem cell, adipose-derived mesenchymal stem cell), injurious diseases (spinal cord injury, acute lung injury, ischemia/reperfusion injury, acute kidney injury, traumatic brain injury), tumor (breast cancer, tumor microenvironment), biological processes (drug delivery system, angiogenesis, inflammation, proliferation, differentiation, senescence), and molecular mechanisms (signaling pathway, signal transduction, oxidative stress, VEGF, TGF β).

Conclusions: Studies on MSC-EVs have shown a steep growth trend in recent years. Available studies mostly focused on the therapeutic effects and underlying mechanisms of MSC-EVs in aplastic diseases. Multidisciplinary integration is a development trend in this field, and senescence-related topics might be the focus of future research on MSC-EVs.

LIM Kinases in Osteosarcoma Development

Tumorigenesis is a long-term and multistage process that often leads to the formation of metastases. During this pathological course, two major events appear to be crucial: primary tumour growth and metastatic expansion. In this context, despite research and clinical advances during the past decades, bone cancers remain a leading cause of death worldwide among paediatric cancer patients. Osteosarcomas are the most common malignant bone tumours in children and adolescents. Notwithstanding advances in therapeutic treatments, many patients succumb to these diseases. In particular, less than 30% of patients who demonstrate metastases at diagnosis or are poor responders to chemotherapy survive 5 years after initial diagnosis. LIM kinases (LIMKs), comprising LIMK1 and LIMK2, are common downstream effectors of several signalization pathways, and function as a signalling node that controls cytoskeleton dynamics through the phosphorylation of the cofilin family proteins. In recent decades, several reports have indicated that the functions of LIMKs are mainly implicated in the regulation of actin microfilament and the control of microtubule dynamics. Previous studies have thus identified LIMKs as cancer-promoting regulators in multiple organ cancers, such as breast cancer or prostate cancer. This review updates the current understanding of LIMK involvement in osteosarcoma progression.

Parathyroid Hormone 1 Receptor Signaling in Dental Mesenchymal Stem Cells: Basic and Clinical Implications

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) are two peptides that regulate mineral ion homeostasis, skeletal development, and bone turnover by activating parathyroid hormone 1 receptor (PTH1R). PTH1R signaling is of profound clinical interest for its potential to stimulate bone formation and regeneration. Recent pre-clinical animal studies and clinical trials have investigated the effects of PTH and PTHrP analogs in the orofacial region. Dental mesenchymal stem cells (MSCs) are targets of PTH1R signaling and have long been known as major factors in tissue repair and regeneration. Previous studies have begun to reveal important roles for PTH1R signaling in modulating the proliferation and differentiation of MSCs in the orofacial region. A better understanding of the molecular networks and underlying mechanisms for modulating MSCs in dental diseases will pave the way for the therapeutic applications of PTH and PTHrP in the future. Here we review recent studies involving dental MSCs, focusing on relationships with PTH1R. We also summarize recent basic and clinical observations of PTH and PTHrP treatment to help understand their use in MSCs-based dental and bone regeneration.

Prospects for Manipulation of Mesenchymal Stem Cells in Tumor Therapy: Anti-Angiogenesis Property on the Spotlight

The interactions between the tumor microenvironment and the tumor cells confers a condition that accelerate or decelerate the development of tumor. Of these cells, mesenchymal stem cells (MSCs) have the potential to modulate the tumor cells. MSCs have been established with double functions, whereby contribute to a tumorigenic or anti-tumor setting. Clinical studies have indicated the potential of MSCs to be used as tool in treating the human cancer cells. One of the advantageous features of MSCs that make them as a well-suited tool for cancer therapy is the natural tumor-trophic migration potential. A key specification of the tumor development has been stablished to be angiogenesis. As a result, manipulation of angiogenesis has become an attractive approach for cancer therapy. This review article will seek to clarify the anti-angiogenesis strategy in modulating the MSCs to treat the tumor cells.

Cell spheroids are as effective as single cells suspensions in the treatment of critical-sized bone defects

Background

Due to their multilineage potential and high proliferation rate, mesenchymal stem cells (MSC) indicate a sufficient alternative in regenerative medicine. In comparison to the commonly used 2-dimensional culturing method, culturing cells as spheroids stimulates the cell-cell communication and mimics the in vivo milieu more accurately, resulting in an enhanced regenerative potential. To investigate the osteoregenerative potential of MSC spheroids in comparison to MSC suspensions, cell-loaded fibrin gels were implanted into murine critical-sized femoral bone defects.

Methods

After harvesting MSCs from 4 healthy human donors and preculturing and immobilizing them in fibrin gel, cells were implanted into 2 mm murine femoral defects and stabilized with an external fixator. Therefore, 26 14- to 15-week-old nu/nu NOD/SCID nude mice were randomized into 2 groups (MSC spheroids, MSC suspensions) and observed for 6 weeks. Subsequently, micro-computed tomography scans were performed to analyze regenerated bone volume and bone mineral density. Additionally, histological analysis, evaluating the number of osteoblasts, osteoclasts and vessels at the defect side, were performed.

Statistical analyzation was performed by using the Student’s t-test and, the Mann-Whitney test. The level of significance was set at p = 0.05.

Results

μCT-analysis revealed a significantly higher bone mineral density of the MSC spheroid group compared to the MSC suspension group. However, regenerated bone volume of the defect side was comparable between both groups. Furthermore, no significant differences in histological analysis between both groups could be shown.

Conclusion

Our in vivo results reveal that the osteo-regenerative potential of MSC spheroids is similar to MSC suspensions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04264-y.

Challenges and advances in clinical applications of mesenchymal stromal cells

Mesenchymal stromal cells (MSCs), also known as mesenchymal stem cells, have been intensely investigated for clinical applications within the last decades. However, the majority of registered clinical trials applying MSC therapy for diverse human diseases have fallen short of expectations, despite the encouraging pre-clinical outcomes in varied animal disease models. This can be attributable to inconsistent criteria for MSCs identity across studies and their inherited heterogeneity. Nowadays, with the emergence of advanced biological techniques and substantial improvements in bio-engineered materials, strategies have been developed to overcome clinical challenges in MSC application. Here in this review, we will discuss the major challenges of MSC therapies in clinical application, the factors impacting the diversity of MSCs, the potential approaches that modify MSC products with the highest therapeutic potential, and finally the usage of MSCs for COVID-19 pandemic disease.

5-Azacytidine pretreatment confers transient upregulation of proliferation and stemness in human mesenchymal stem cells

Successful outcomes of cell-based therapeutic is highly-dependent on quality and quantity of the cells. Epigenetic modifiers are known to modulate cell fates via reprogramming, hence it is plausible to use them in enhancing the plasticity of mesenchymal stem cells. In this study, we aimed to study the effects of 5-Azacytidine (5-AzaCR), an epigenetic modifier, pretreatment on mesenchymal stem cells-derived from Wharton's Jelly (WJMSCs) fates. WJMSCs were pretreated with 5-AzaCR for 24 h and subsequently cultured in culture media mixtures. The proliferative and stemness characteristics of the pretreated WJMSCs were assessed through morphological and gene expression analyses. Results showed that cells pretreated with 5 μM to 20 μM of 5-AzaCR showed to acquire higher proliferative state transiently when cultured in embryonic-mesenchymal stem cell (ESC-MSC) media, but not in MSC medium alone, and this coincides with significant transitional upregulation of stemness transcription factors. 5-AzaCR pretreatment has potential to confer initial induction of higher state of stemness and proliferation in WJMSCs, influenced by the culture media.

Culture, Expansion and Differentiation of Human Bone Marrow Stromal Cells

Mesenchymal stromal cells (MSC) are a rare, heterogeneous and multipotent population that can be isolated from several tissues. MSC were originally discovered in the bone marrow and studied for their capacity to maintain hematopoietic cells. We will describe here methods to isolate, culture, and bank MSC from human bone marrow. Then, characterization protocols by flow cytometry, clonogenic assays and doubling time evaluation will be developed. Finally, in vitro MSC culture and differentiation into osteoblasts, adipocytes, and chondrocytes will be explained. Thus, this chapter will detail all bases to work on MSC with consensus and clear methods and protocols.

Osteogenic differentiation and inflammatory response of recombinant human bone morphogenetic protein-2 in human maxillary sinus membrane-derived cells

The aim of the present study was to investigate the osteogenic potential of human maxillary sinus membrane (hMSM)-derived cells, and the role of recombinant human bone morphogenetic protein-2 (rhBMP-2) in the inflammatory response of hMSM-derived cells and gingival fibroblasts following sinus floor elevation procedure (SFE). hMSM-derived cells from the samples were isolated, subcultured, and analyzed using immunohistochemical staining and flow cytometry. The hMSM-derived cells obtained from passage 6 were used for Alizarin Red staining and quantitative reverse transcription-quantitative PCR to observe its osteogenic activity and inflammatory reaction upon supplementation with rhBMP-2. The hMSM-derived cells were shown to be heterogeneous, as indicated by their positive expression of human mesenchymal stem cell markers (STRO-1, high mobility group AT-hook 2, CD44, CD105 and OCT-3/4), fibroblast cell marker (fibroblast-specific protein 1) and epithelial cell marker (epithelial cell adhesion molecule). Calcium nodules were found to be more notably evident in the rhBMP-2 group, following osteogenic differentiation. The gene expression of osteogenic markers was significantly upregulated in the cells supplemented with rhBMP-2. Supplementation with rhBMP-2 also enhanced the expression of inflammatory markers in hMSM-derived cells and gingival fibroblasts; however, NF-κB and TNF-α expression was not significantly increased compared with the control in the hMSM-derived cells. hMSM contains mesenchymal stem cells (MSCs) capable of differentiating into osteogenic cells. The supplementation of rhBMP-2 enhanced osteogenic differentiation and induced an inflammatory response which was greater in gingival fibroblasts compared with hMSM-derived cells. In summary, the hMSM is a potential contributor to the osteogenic process following SFE, and the use of rhBMP-2 may increase the inflammatory response accordingly. The gingival tissue may be responsible for the increased inflammatory response by rhBMP-2 and postoperative complications.

Human Menstrual Blood Stem Cell-Derived Granulosa Cells Participate in Ovarian Follicle Formation in a Rat Model of Premature Ovarian Failure In Vivo

We recently reported the application of human menstrual blood stem cells' (HuMenSCs) transplantation as a treatment modality in a rat model of premature ovarian failure (POF). We continued to investigate further in this respect. Female rats were injected intraperitoneally with 36 mg/kg busulfan. HuMenSCs were obtained, grown, and analyzed for immunophenotypic features at passage three. The cells were labeled with CM-Dil and infused into the rats. There were four groups: normal, negative control, treatment, and Sham. One month after treatment, the ovaries were collected and weighed. Histological sections were prepared from the ovary and HuMenSCs were tracking. Subsequently, we examined the changes of expression of Bax and B cell lymphoma 2 (Bcl2) genes by real-time polymerase chain reaction assay. One month after HuMenSCs transplantation, these cells were located in the ovarian interstitium and granulosa cells (GCs). The number of TUNEL-positive cells significantly decreased in the treatment group. Also the expression level of Bax genes, unlike Bcl2 gene, significantly decreased compared with negative and sham groups. In our study, HuMenSCs were tracked in ovarian tissues within 2 months after transplantation, and they differentiated into GCs. Therefore, the use of these cells can be a practical and low-cost method for the treatment of POF patients.

RNA-Seq analysis reveals the potential molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle

Daidzein has been reported to be effective in regulating lipid metabolism in animals. However, the molecular mechanisms of daidzein on adipogenesis in beef cattle are not yet reported and the results of daidzein on affecting lipid metabolism in other species have been conflicting. High-throughput sequencing of mRNA (RNA-Seq) technology was performed to elucidate the underlying molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle. A total of 893 differentially expressed genes (DEGs) were identified by differential expression analysis, among which 405 genes were upregulated and 488 genes were downregulated. Bioinformatics analysis suggested that these DEGs were significantly enriched to the pathways related to lipid metabolism including ECM-receptor interaction, Glycolysis/Gluconeogenesis and Hedgehog signalling pathway. Daidzein significantly affected the candidate genes (Shh, Pec, Gli, Wnt6, DLK, IGFBP2, ID3 and C/EBPE) related to adipocyte differentiation. Besides, daidzein improved the ability of subcutaneous adipocytes in synthesizing triglycerides by directly using the long-chain fatty acids and enhanced the efficiency of triglyceride synthesis of subcutaneous adipocytes in Xianan steers. In conclusion, daidzein plays a positive role not only in adipogenic differentiation, but also in triglyceride synthesis in subcutaneous adipose tissue of Xianan beef cattle.

The Role of Mesenchymal Stem Cells in Atherosclerosis: Prospects for Therapy via the Modulation of Inflammatory Milieu

Atherosclerosis is a chronic, inflammatory disease that mainly affects the arterial intima. The disease is more prevalent in middle-age and older individuals with one or more cardiovascular risk factors, including dyslipidemia, hypertension, diabetes, smoking, obesity, and others. The beginning and development of atherosclerosis has been associated with several immune components, including infiltration of inflammatory cells, monocyte/macrophage-derived foam cells, and inflammatory cytokines and chemokines. Mesenchymal stem cells (MSCs) originate from several tissue sources of the body and have self-renewal and multipotent differentiation characteristics. They also have immunomodulatory and anti-inflammatory properties. Recently, it was shown that MSCs have a regulatory role in plasma lipid levels. In addition, MSCs have shown to have promising potential in terms of treatment strategies for several diseases, including those with an inflammatory component. In this regard, transplantation of MSCs to patients with atherosclerosis has been proposed as a novel strategy in the treatment of this disease. In this review, we summarize the current advancements regarding MSCs for the treatment of atherosclerosis.

New Insights Into Implementation of Mesenchymal Stem Cells in Cancer Therapy: Prospects for Anti-angiogenesis Treatment

Tumor microenvironment interacts with tumor cells, establishing an atmosphere to contribute or suppress the tumor development. Among the cells which play a role in the tumor microenvironment, mesenchymal stem cells (MSCs) have been demonstrated to possess the ability to orchestrate the fate of tumor cells, drawing the attention to the field. MSCs have been considered as cells with double-bladed effects, implicating either tumorigenic or anti-tumor activity. On the other side, the promising potential of MSCs in treating human cancer cells has been observed from the clinical studies. Among the beneficial characteristics of MSCs is the natural tumor-trophic migration ability, providing facility for drug delivery and, therefore, targeted treatment to detach tumor and metastatic cells. Moreover, these cells have been the target of engineering approaches, due to their easily implemented traits, in order to obtain the desired expression of anti-angiogenic, anti-proliferative, and pro-apoptotic properties, according to the tumor type. Tumor angiogenesis is the key characteristic of tumor progression and metastasis. Manipulation of angiogenesis has become an attractive approach for cancer therapy since the introduction of the first angiogenesis inhibitor, namely bevacizumab, for metastatic colorectal cancer therapy. This review tries to conclude the approaches, with focus on anti-angiogenesis approach, in implementing the MSCs to combat against tumor cell progression.

Oxygen-laden mesenchymal stem cells enhance the effect of gastric cancer chemotherapy in vitro

Hypoxia is an important factor that results in failure of chemotherapy for the majority of solid tumor types, particularly for gastric cancer. In the present study, mesenchymal stem cells (MSCs), which have the ability to migrate to cancer tissues were used as a vehicle to supply oxygen to gastric cancer. The hemoglobin genes were transfected into MSCs as MSC-hemo groups. Subsequently, MSC-hemo groups were induced by isopropyl-b-D-thiogalactopyranoside and hemin to express hemoglobin. The hemoglobin was detected by western blotting method. Following this, the MSC-hemo groups were placed in an atmosphere containing 100% oxygen and were used to investigate the effect of the function of the oxygen-laden MSC-hemo group on gastric cancer chemotherapy with an MTT assay. As a first approach to investigate the possibility of MSCs as a vehicle to supply oxygen to anoxic cancer types, including gastric, liver, breast cancer, the results indicated that the oxygen-laden MSC-hemo group significantly enhanced the effect of chemotherapeutic treatments on gastric cancer cells. Utilizing MSCs as a svehicle to supply oxygen to the solid tumor may be a novel method to improve the hypoxia conditions of tumor tissues and improve the effect of chemotherapy on tumor cells.

Administration of Cripto in GRP78 overexpressed human MSCs enhances stem cell viability and angiogenesis during human MSC transplantation therapy

OBJECTIVES

The purpose of this study was to explore the effectiveness of concurrent GRP78 overexpression combined with Cripto on hMSC proliferation and migration both in vitro and in vivo. Specifically, we explored whether the treatment enhances effectiveness of hMSC transplantation in ischaemic tissue.

MATERIALS AND METHODS

Human MSCs obtained from human adipose tissue were cultured in α-minimum essential medium (Hyclone, Logan, UT, USA) supplemented with 10% (v/v) foetal bovine serum (Hyclone), 100 U mL^-1 penicillin and 100 μg mL^-1 streptomycin. Murine hindlimb ischaemic model was generated with 8-week-old male nude BALB/c mice (Biogenomics, Seoul, Korea) maintained under a 12-h light/dark cycle following the established protocol with minor modification. Cellular injection was performed no later than 3 hour after surgery. Lipofectamine transfection, single-cell cultivation assay, transwell assay, scratch wound-healing migration assay, immunohistochemistry and western blotting assays were performed.

RESULTS

Overexpression of GRP78 along with Cripto enhanced hMSC proliferation, migration and invasion. It increased interaction of surface GRP78 receptor with Cripto via JAK2/STAT3 pathway. We confirmed our proposed mechanism by showing that treatment with GRP78 antibody blocks the enhancement in vitro. In vivo, we observed that Cripto induced by the hypoxic environment in hindlimb ischaemic model interacts with the overexpressed GRP78 and increases hMSC proliferation, migration and invasion potentials as well as angiogenesis around transplanted ischaemic site via cytokine secretions.

CONCLUSIONS

These results demonstrate supporting evidences that GRP78-Cripto combination technique offers novel strategy to enhance MSC proliferation, migration and invasion potentials as well as angiogenesis around ischaemic site, ultimately facilitating MSC-based transplantation therapy in ischaemic conditions.

Mesenchymal stem cell transplantation in systemic lupus erythematous, a mesenchymal stem cell disorder

Systemic lupus erythematosus (SLE) is a chronic autoimmune and inflammatory disorder with involvement of several organs and systems such as the kidney, lung, brain and the hematopoietic system. As the most prevailing organ manifestation, lupus nephritis is the major cause of mortality and morbidity in SLE patients. The most classically and widely administered immunosuppressive medications, namely corticosteroids and cyclophosphamide, have eventuated in a remarkable amelioration in disease complications over the last few years and reduced the progression to end-stage multiorgan failure. Mesenchymal stem cells (MSCs) are considered as non-hematopoietic and multipotential progenitor cells, which are able to differentiate into multiple cell lineages such as chondrocytes, osteoblasts, myoblasts, endothelial cells, adipocytes, neuron-like cells, hepatocytes and cardiomyocytes. MSCs from SLE patients have demonstrated defects such as aberrant cytokine production. Moreover, impaired phenotype, growth and immunomodulatory functions of MSCs from patients with SLE in comparison to healthy controls have been reported. Therefore, it is hypothesized that SLE is potentially an MSC-mediated disease and, as a result, allogeneic rather than autologous MSC transplantation can be argued to be a potentially advantageous therapy for patients with SLE. On the other hand, the MSC senescence phenomenon may meet the current therapeutic approaches with challenges and demand more attention. Here, we discuss MSC transplantations to date in animal models and humans and focus on the MSC senescence complications in SLE patients.

TGFβ-1 and epithelial-mesenchymal interactions promote smooth muscle gene expression in bone marrow stromal cells: Possible application in therapies for urological defects

Purpose

For regenerative and cellular therapies of the urinary tract system, autologous bladder smooth muscle cells (SMCs) have several limitations, including constricted in vitro proliferation capacity and, more importantly, inability to be used in malignant conditions. The use of in vitro (pre-)differentiated multipotential adult progenitor cells may help to overcome the shortcomings associated with primary cells.

Methods

By mimicking environmental conditions of the bladder wall, we investigated in vitro effects of growth factor applications and epithelial-mesenchymal interactions on smooth muscle gene expression and on the morphological appearance of adherent bone marrow stromal cells (BMSCs).

Results

Transcription growth factor beta-1 (TGFβ-1) upregulated the transcription of myogenic gene desmin and smooth muscle actin-γ2 in cultured BMSCs. Stimulatory effects were significantly increased by coculture with urothelial cells. Prolonged stimulation times and epigenetic modifications further enhanced transcription levels, indicating a dose-response relationship. Immunocytochemical staining of in vitro-differentiated BMSCs revealed expression of myogenic protein α-smooth muscle actin and desmin, and changes in morphological appearance from a fusiform convex shape to a laminar flattened shape with filamentous inclusions similar to the appearance of bladder SMCs. In contrast to the TGFβ-1 action, application of vascular endothelial growth factor (VEGF) did not affect the cells.

Conclusions

The combined application of TGFβ-1 and epithelial-mesenchymal interactions promoted in vitro outgrowth of cells with a smooth muscle-like phenotype from a selected adherent murine bone marrow-derived cell population.

Adult Stem Cells of Orofacial Origin: Current Knowledge and Limitation and Future Trend in Regenerative Medicine

Stem cell research is one of the most rapidly expanding field of medicine which provides significant opportunities for therapeutic and regenerative applications. Different types of stem cells have been isolated investigating their accessibility, control of the differentiation pathway and additional immunomodulatory properties. Bulk of the literature focus has been on the study and potential applications of adult stem cells (ASC) because of their low immunogenicity and reduced ethical considerations. This review paper summarizes the basic available literature on different types of ASC with special focus on stem cells from dental and orofacial origin. ASC have been isolated from different sources, however, isolation of ASC from orofacial tissues has provided a novel promising alternative. These cells offer a great potential in the future of therapeutic and regenerative medicine because of their remarkable availability at low cost while allowing minimally invasive isolation procedures. Furthermore, their immunomodulatory and anti-inflammatory potential is of particular interest. However, there are conflicting reports in the literature regarding their particular biology and full clinical potentials. Sound knowledge and higher control over proliferation and differentiation mechanisms are prerequisites for clinical applications of these cells. Therefore, further standardized basic and translational studies are required to increase the reproducibility and reduce the controversies of studies, which in turn facilitate comparison of related literature and enhance further development in the field.

Connexin43 intercellular communication drives the early differentiation of human bone marrow stromal cells into osteoblasts

Although it has been demonstrated that human bone marrow stromal cells (hBMSCs) express the ubiquitous connexin43 (Cx43) and form functional gap junctions, their role in the early differentiation of hBMSCs into osteoblasts remains poorly documented. Using in vitro assays, we show that Cx43 expression and gap junctional intercellular communication (GJIC) are increased during the differentiation of hBMSCs into osteoblasts, both at the protein and mRNA levels. Two independent procedures to reduce GJIC, a pharmacological approach with GJIC inhibitors (18α-glycyrrhetinic acid and Gap27 peptide) and a molecular approach using small interfering RNA against Cx43, demonstrated that the presence of Cx43 and functional junctional channels are essential to the ability of hBMSCs to differentiate into osteoblasts in vitro. In addition, a reduced GJIC decreases the expression of Runx2, the major transcription factor implicated in the control of osteoblast commitment and early differentiation of hBMSCs into osteoblasts, suggesting that GJIC mediated by Cx43 is implicated in this process. Together our results demonstrate that GJIC mediated by the Cx43 channels plays a central role throughout the differentiation of hBMSC into osteoblasts, from the early stages to the process of mineralization.

A nanofibrous electrospun patch to maintain human mesenchymal cell stemness

Mesenchymal stem cells (MSCs) have been extensively investigated in regenerative medicine because of their crucial role in tissue healing. For these properties, they are widely tested in clinical trials, usually injected in cell suspension or in combination with tridimensional scaffolds. However, scaffolds can largely affect the fates of MSCs, inducing a progressive loss of functionality overtime. The ideal scaffold must delay MSCs differentiation until paracrine signals from the host induce their change. Herein, we proposed a nanostructured electrospun gelatin patch as an appropriate environment where human MSCs (hMSCs) can adhere, proliferate, and maintain their stemness. This patch exhibited characteristics of a non-linear elastic material and withstood degradation up to 4 weeks. As compared to culture and expansion in 2D, hMSCs on the patch showed a similar degree of proliferation and better maintained their progenitor properties, as assessed by their superior differentiation capacity towards typical mesenchymal lineages (i.e. osteogenic and chondrogenic). Furthermore, immunohistochemical analysis and longitudinal non-invasive imaging of inflammatory response revealed no sign of foreign body reaction for 3 weeks. In summary, our results demonstrated that our biocompatible patch favored the maintenance of undifferentiated hMSCs for up to 21 days and is an ideal candidate for tridimensional delivery of hMSCs. The present work reports a nanostructured patch gelatin-based able to maintain in vitro hMSCs stemness features. Moreover, hMSCs were able to differentiate toward osteo- and chondrogenic lineages once induces by differentiative media, confirming the ability of this patch to support stem cells for a potential in vivo application. These attractive properties together with the low inflammatory response in vivo make this patch a promising platform in regenerative medicine.

Bone marrow mesenchymal stem cells regulate stemness of multiple myeloma cell lines via BTK signaling pathway

Bone marrow mesenchymal stem cells (BM-MSCs) are key components of bone marrow microenvironment. Although the importances of BM-MSCs activation in myeloma cells growth, development, progression, angiogenesis are well known, their role in the regulation of myeloma stemness is unclear. In this study, myeloma cell lines (LP-1, U266) were co-cultured with BM-MSCs, we found that BM-MSCs could up-regulate the expression of key stemness genes and proteins (OCT4, SOX2, NANOG) and increase clonogenicity. Similarly, the mechanisms underlying the BM-MSC activation of myeloma stemness remain unclear. Here, we found that PCI-32765, a Bruton tyrosine kinase (BTK) inhibitor, treatment significantly down- regulate expression of key stemness genes and proteins in vitro co-culture system. Together, our results revealed that BM-MSCs could increase myeloma stemness via activation of the BTK signal pathway.

Mesenchymal stem cells in the aseptic loosening of total joint replacements

Peri-prosthetic osteolysis remains as the main long-term complication of total joint replacement surgery. Research over four decades has established implant wear as the main culprit for chronic inflammation in the peri-implant tissues and macrophages as the key cells mediating the host reaction to implant-derived wear particles. Wear debris activated macrophages secrete inflammatory mediators that stimulate bone resorbing osteoclasts; thus bone loss in the peri-implant tissues is increased. However, the balance of bone turnover is not only dictated by osteoclast-mediated bone resorption but also by the formation of new bone by osteoblasts; under physiological conditions these two processes are tightly coupled. Increasing interest has been placed on the effects of wear debris on the cells of the bone-forming lineage. These cells are derived primarily from multipotent mesenchymal stem cells (MSCs) residing in bone marrow and the walls of the microvasculature. Accumulating evidence indicates that wear debris significantly impairs MSC-to-osteoblast differentiation and subsequent bone formation. In this review, we summarize the current understanding of the effects of biomaterial implant wear debris on MSCs. Emerging treatment options to improve initial implant integration and treat developing osteolytic lesions by utilizing or targeting MSCs are also discussed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1195-1207, 2017.

Tumor-homing effect of human mesenchymal stem cells in a TH-MYCN mouse model of neuroblastoma

BACKGROUND

Human mesenchymal stem cells (hMSCs) are multipotent stem-like cells that are reported to have tumor-suppression effects and migration ability toward damaged tissues or tumors. The aim of this study was to analyze the tumor-homing ability of hMSCs and antitumor potency in a transgenic TH-MYCN mouse model of neuroblastoma (NB).

METHODS

hMSCs (3×10⁶) labeled with DiR, a lipophilic near-infrared dye, were intraperitoneally (i.p.) or intravenously (i.v.) administered to the TH-MYCN mice. hMSC in vivo kinetics were assayed using the IVIS® imaging system for 24h after injection. Immunohistochemistry using human CD90 antibody was also performed to confirm the location of hMSCs in various organs and tumors. Furthermore, the survival curve of TH-MYCN mice treated with hMSCs was compared to a control group administered PBS.

RESULTS

i.p. hMSCs were recognized in the tumors of TH-MYCN mice by IVIS. hMSCs were also located inside the tumor tissue. Conversely, most of the i.v. hMSCs were captured by the lungs, and migration into the tumors was not noted. There was no significant difference in the survival between the hMSC and control groups.

CONCLUSION

The present study suggested that hMSCs may be potential tumor-specific therapeutic delivery vehicles in NB according to their homing potential to tumors.

Mesenchymal stem cells as a double-edged sword in suppression or progression of solid tumor cells

Tumor cells are able to attract mesenchymal stem cells (MSCs) to primary tumor site. On the other hand, MSCs secrete various factors to attract tumor cells towards BM. In this review, in addition to assessment of MSCs function at tumor sites and their impact on growth and metastasis of tumor cells, the importance of MSC in attraction of malignant cells to BM and their involvement in drug resistance of tumor cells have also been studied. Relevant literature was identified by a PubMed search (2000-2015) of English-language literature using the terms mesenchymal stem cells, cancer cell, metastasis, and tumor microenvironment. MSCs migrate towards tumor microenvironment and are involved in both pro-tumorigenic and antitumorigenic functions. The dual function of MSCs at tumor sites is dependent upon a variety of factors, including the type and origin of MSCs, the cancer cell line under study, in vivo or in vitro conditions, the factors secreted by MSCs and interactions between MSCs, host immune cells and cancer cells. Therefore, MSCs can be regarded both as friends and enemies of cancer cells. Although the role of a number of pathways, including IL-6/STAT3 pathway, has been indicated in controlling the interaction between MSCs and tumor cells, other mechanisms by which MSCs can control the tumor cells are not clear yet. A better understanding of these mechanisms through further studies can determine the exact role of MSCs in cancer progression and identify them as important therapeutic agents or targets.

Mesenchymal stem cell therapy in the treatment of osteoarthritis: reparative pathways, safety and efficacy - a review

Osteoarthritis is a leading cause of pain and disability across the world. With an aging population its prevalence is likely to further increase. Current accepted medical treatment strategies are aimed at symptom control rather than disease modification. Surgical options including joint replacement are not without possible significant complications. A growing interest in the area of regenerative medicine, led by an improved understanding of the role of mesenchymal stem cells in tissue homeostasis and repair, has seen recent focused efforts to explore the potential of stem cell therapies in the active management of symptomatic osteoarthritis. Encouragingly, results of pre-clinical and clinical trials have provided initial evidence of efficacy and indicated safety in the therapeutic use of mesenchymal stem cell therapies for the treatment of knee osteoarthritis. This paper explores the pathogenesis of osteoarthritis and how mesenchymal stem cells may play a role in future management strategies of this disabling condition.

The Effect of Bone Marrow Mesenchymal Stem Cells on Vitamin D3 Induced Monocytic Differentiation of U937 Cells

PURPOSE

Mesenchymal stem cells (MSCs) are key components of the hematopoietic stem cells (HSCs) niche. They control the process of hematopoiesis by secreting regulatory cytokines, growth factors and expression of important cell adhesion molecules for cell-tocell interactions. In this research, we have investigated the effect of bone marrow derived MSCs on monocytic differentiation of U937 cells line.

METHODS

U937 cells were cultured in both direct co-culture with MSCs and MSCs conditioned medium (C.M) driven. This study used 1,25-dihydroxyvitamin D3(VitD3) as inductor of monocytic differentiation and U937 cells treated with VitD3 morphology was examined by Wright Giemsa staining. CD14 monocytic differentiation marker was measured by flow cytometry and monocytic gene expression was assessed by real time polymerase chain reaction (RT PCR).

RESULTS

The results of flow cytometric analysis showed that CD14 expression of U937 increased. The higher effect of MSCs co-culture on CD14 expression in U937 cells was observed, compared to the conditioned medium. Among ten monocytic related genes which were screened that was observed increase in 5 genes in which CXCR4 and CSF2RA showed significant increase.

CONCLUSION

The results obtained show that MSCs have supportive effect on the monocytic differentiation of U937 cells. However, a distinct mechanism of that remains unclear.

Glycosaminoglycan-Mimetic Signals Direct the Osteo/Chondrogenic Differentiation of Mesenchymal Stem Cells in a Three-Dimensional Peptide Nanofiber Extracellular Matrix Mimetic Environment

Recent efforts in bioactive scaffold development focus strongly on the elucidation of complex cellular responses through the use of synthetic systems. Designing synthetic extracellular matrix (ECM) materials must be based on understanding of cellular behaviors upon interaction with natural and artificial scaffolds. Hence, due to their ability to mimic both the biochemical and mechanical properties of the native tissue environment, supramolecular assemblies of bioactive peptide nanostructures are especially promising for development of bioactive ECM-mimetic scaffolds. In this study, we used glycosaminoglycan (GAG) mimetic peptide nanofiber gel as a three-dimensional (3D) platform to investigate how cell lineage commitment is altered by external factors. We observed that amount of fetal bovine serum (FBS) presented in the cell media had synergistic effects on the ability of GAG-mimetic nanofiber gel to mediate the differentiation of mesenchymal stem cells into osteogenic and chondrogenic lineages. In particular, lower FBS concentration in the culture medium was observed to enhance osteogenic differentiation while higher amount FBS promotes chondrogenic differentiation in tandem with the effects of the GAG-mimetic 3D peptide nanofiber network, even in the absence of externally administered growth factors. We therefore demonstrate that mesenchymal stem cell differentiation can be specifically controlled by the combined influence of growth medium components and a 3D peptide nanofiber environment.

The Effect of Bone Marrow Mesenchymal Stem Cells on Vitamin D3 Induced Monocytic Differentiation of U937 Cells

PURPOSE

Mesenchymal stem cells (MSCs) are key components of the hematopoietic stem cells (HSCs) niche. They control the process of hematopoiesis by secreting regulatory cytokines, growth factors and expression of important cell adhesion molecules for cell-tocell interactions. In this research, we have investigated the effect of bone marrow derived MSCs on monocytic differentiation of U937 cells line.

METHODS

U937 cells were cultured in both direct co-culture with MSCs and MSCs conditioned medium (C.M) driven. This study used 1,25-dihydroxyvitamin D3(VitD3) as inductor of monocytic differentiation and U937 cells treated with VitD3 morphology was examined by Wright Giemsa staining. CD14 monocytic differentiation marker was measured by flow cytometry and monocytic gene expression was assessed by real time polymerase chain reaction (RT PCR).

RESULTS

The results of flow cytometric analysis showed that CD14 expression of U937 increased. The higher effect of MSCs co-culture on CD14 expression in U937 cells was observed, compared to the conditioned medium. Among ten monocytic related genes which were screened that was observed increase in 5 genes in which CXCR4 and CSF2RA showed significant increase.

CONCLUSION

The results obtained show that MSCs have supportive effect on the monocytic differentiation of U937 cells. However, a distinct mechanism of that remains unclear.

Adipose derived mesenchymal stem cell therapy in the treatment of isolated knee chondral lesions: design of a randomised controlled pilot study comparing arthroscopic microfracture versus arthroscopic microfracture combined with postoperative mesenchymal stem cell injections

INTRODUCTION

The management of intra-articular chondral defects in the knee remains a challenge. Inadequate healing in areas of weight bearing leads to impairment in load transmission and these defects predispose to later development of osteoarthritis. Surgical management of full thickness chondral defects include arthroscopic microfracture and when appropriate autologous chondrocyte implantation. This latter method however is technically challenging, and may not offer significant improvement over microfracture. Preclinical and limited clinical trials have indicated the capacity of mesenchymal stem cells to influence chondral repair. The aim of this paper is to describe the methodology of a pilot randomised controlled trial comparing arthroscopic microfracture alone for isolated knee chondral defects versus arthroscopic microfracture combined with postoperative autologous adipose derived mesenchymal stem cell injections.

METHODS AND ANALYSIS

A pilot single-centre randomised controlled trial is proposed. 40 participants aged 18-50 years, with isolated femoral condyle chondral defects and awaiting planned arthroscopic microfracture will be randomly allocated to a control group (receiving no additional treatment) or treatment group (receiving postoperative adipose derived mesenchymal stem cell treatment). Primary outcome measures will include MRI assessment of cartilage volume and defects and the Knee Injury and Osteoarthritis Outcome Score. Secondary outcomes will include further MRI assessment of bone marrow lesions, bone area and T2 cartilage mapping, a 0-10 Numerical Pain Rating Scale, a Global Impression of Change score and a treatment satisfaction scale. Adverse events and cointerventions will be recorded. Initial outcome follow-up for publication of results will be at 12 months. Further annual follow-up to assess long-term differences between the two group will occur.

ETHICS AND DISSEMINATION

This trial has received prospective ethics approval through the Latrobe University Human Research Ethics Committee. Dissemination of outcome data is planned through both national and international conferences and formal publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Australia and New Zealand Clinical Trials Register (ANZCTR Trial ID: ACTRN12614000812695).

Activated Schwann Cell-Like Cells on Aligned Fibrin-Poly(Lactic-Co-Glycolic Acid) Structures: A Novel Construct for Application in Peripheral Nerve Regeneration

Tissue engineering approaches in nerve regeneration search for ways to support gold standard therapy (autologous nerve grafts) and to improve results by bridging nerve defects with different kinds of conduits. In this study, we describe electrospinning of aligned fibrin-poly(lactic-co-glycolic acid) (PLGA) fibers in an attempt to create a biomimicking tissue-like material seeded with Schwann cell-like cells (SCLs) in vitro for potential use as an in vivo scaffold. Rat adipose-derived stem cells (rASCs) were differentiated into SCLs and evaluated with flow cytometry concerning their differentiation and activation status [S100b, P75, myelin-associated glycoprotein (MAG), and protein 0 (P0)]. After receiving the proliferation stimulus forskolin, SCLs expressed S100b and P75; comparable to native, activated Schwann cells, while cultured without forskolin, cells switched to a promyelinating phenotype and expressed S100b, MAG, and P0. Human fibrinogen and thrombin, blended with PLGA, were electrospun and the alignment and homogeneity of the fibers were proven by scanning electron microscopy. Electrospun scaffolds were seeded with SCLs and the formation of Büngner-like structures in SCLs was evaluated with phalloidin/propidium iodide staining. Carrier fibrin gels containing rASCs acted as a self-shaping matrix to form a tubular structure. In this study, we could show that rASCs can be differentiated into activated, proliferating SCLs and that these cells react to minimal changes in stimulus, switching to a promyelinating phenotype. Aligned electrospun fibrin-PLGA fibers promoted the formation of Büngner-like structures in SCLs, which also rolled the fibrin-PLGA matrix into a tubular scaffold. These in vitro findings favor further in vivo testing.

Biomolecular bases of the senescence process and cancer. A new approach to oncological treatment linked to ageing

Human ageing is associated with a gradual decline in the physiological functions of the body at multiple levels and it is a key risk factor for many diseases, including cancer. Ageing process is intimately related to widespread cellular senescence, characterised by an irreversible loss of proliferative capacity and altered functioning associated with telomere attrition, accumulation of DNA damage and compromised mitochondrial and metabolic function. Tumour and senescent cells may be generated in response to the same stimuli, where either cellular senescence or transformation would constitute two opposite outcomes of the same degenerative process. This paper aims to review the state of knowledge on the biomolecular relationship between cellular senescence, ageing and cancer. Importantly, many of the cell signalling pathways that are found to be altered during both cellular senescence and tumourigenesis are regulated through shared epigenetic mechanisms and, therefore, they are potentially reversible. MicroRNAs are emerging as pivotal players linking ageing and cancer. These small RNA molecules have generated great interest from the point of view of future clinical therapy for cancer because successful experimental results have been obtained in animal models. Micro-RNA therapies for cancer are already being tested in clinical phase trials. These findings have potential importance in cancer treatment in aged people although further research-based knowledge is needed to convert them into an effective molecular therapies for cancer linked to ageing.

Mechanism of cell integration on biomaterial implant surfaces in the presence of bacterial contamination

Bacterial contamination during biomaterial implantation is often unavoidable, yielding a combat between cells and bacteria. Here we aim to determine the modulatory function of bacterial components on stem-cell, fibroblast, and osteoblast adhesion to a titanium alloy, including the role of toll-like-receptors (TLRs). Presence of heat-sacrificed Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, or Pseudomonas aeruginosa induced dose and cell-type dependent responses. Stem-cells were most sensitive to bacterial presence, demonstrating decreased adhesion number yet increased adhesion effort with a relatively large focal adhesion contact area. Blocking TLRs had no effect on stem-cell adhesion in presence of S. aureus, but blocking both TLR2 and TLR4 induced an increased adhesion effort in presence of E. coli. Neither lipopolysaccharide, lipoteichoic acid, nor bacterial DNA provoked the same cell response as did whole bacteria. Herewith we suggest a new mechanism as to how biomaterials are integrated by cells despite the unavoidable presence of bacterial contamination. Stimulation of host cell integration of implant surfaces may open a new window to design new biomaterials with enhanced healing, thereby reducing the risk of biomaterial-associated infection of both "hardware-based" implants as well as of tissue-engineered constructs, known to suffer from similarly high infection risks as currently prevailing in "hardware-based" implants.

Neural crest: The fourth germ layer

The neural crest cells (NCCs), a transient group of cells that emerges from the dorsal aspect of the neural tube during early vertebrate development has been a fascinating group of cells because of its multipotency, long range migration through embryo and its capacity to generate a prodigious number of differentiated cell types. For these reasons, although derived from the ectoderm, the neural crest (NC) has been called the fourth germ layer. The non neural ectoderm, the neural plate and the underlying mesoderm are needed for the induction and formation of NC cells. Once formed, NC cells start migrating as a wave of cells, moving away from the neuroepithelium and quickly splitting into distinct streams. These migrating NCCs home in to different regions and give rise to plethora of tissues. Umpteen number of signaling molecules are essential for formation, epithelial mesenchymal transition, delamination, migration and localization of NCC. Authors believe that a clear understanding of steps and signals involved in NC formation, migration, etc., may help in understanding the pathogenesis behind cancer metastasis and many other diseases. Hence, we have taken this review to discuss the various aspects of the NC cells.

Murine embryonic fibroblast cell lines differentiate into three mesenchymal lineages to different extents: new models to investigate differentiation processes

Various diseases, injuries, and congenital abnormalities may result in degeneration and loss of organs and tissues. Recently, tissue engineering has offered new treatment options for these common, severe, and costly problems in human health care. Its application is often based on the usage of differentiated stem cells. However, despite intensive research and growing knowledge, many questions remain unresolved in the process of cell differentiation. The aim of this study was to find standardized cell models for analyzing molecular mechanisms of cell differentiation. We investigated the multipotency of three standardized murine embryonic fibroblast cell cultures using histological staining, western blotting, and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Our results demonstrated that NIH-3T3 and mouse embryonic fibroblast (MEF) cells were able to differentiate into adipogenic, chondrogenic, and osteogenic lineages expressing typical differentiation markers. Interestingly, Flp-In-3T3 cells did not differentiate into any of the three mesenchymal lineages, although this cell line is genetically closely related to NIH-3T3. The results were confirmed by histological staining. Flp-In-3T3, NIH-3T3, and MEF cells have usually been used for DNA transfections, recombinant protein expression, and as "feeder cells." Unlike mesenchymal stem cells (MSCs) and mesenchymal progenitor cells (MPCs), they are easy to obtain and to expand and are less prone to change their structure and morphology, even at higher passages. Our results suggest that Flp-In-3T3, MEF, and NIH-3T3 cells are highly suitable to be used as models to analyze molecular mechanisms of cell differentiation.