MMP-2 and Notch signal pathway regulate migration of adipose-derived stem cells and chondrocytes in co-culture systems

Current Advances in 3D Dynamic Cell Culture Systems

The traditional two-dimensional (2D) cell culture methods have a long history of mimicking in vivo cell growth. However, these methods cannot fully represent physiological conditions, which lack two major indexes of the in vivo environment; one is a three-dimensional 3D cell environment, and the other is mechanical stimulation; therefore, they are incapable of replicating the essential cellular communications between cell to cell, cell to the extracellular matrix, and cellular responses to dynamic mechanical stimulation in a physiological condition of body movement and blood flow. To solve these problems and challenges, 3D cell carriers have been gradually developed to provide a 3D matrix-like structure for cell attachment, proliferation, differentiation, and communication in static and dynamic culture conditions. 3D cell carriers in dynamic culture systems could primarily provide different mechanical stimulations which further mimic the real in vivo microenvironment. In this review, the current advances in 3D dynamic cell culture approaches have been introduced, with their advantages and disadvantages being discussed in comparison to traditional 2D cell culture in static conditions.

What we have learnt from Drosophila model organism: the coordination between insulin signaling pathway and tumor cells

Cancer development is related to a variety of signaling pathways which mediate various cellular processes including growth, survival, division and competition of cells, as well as cell-cell interaction. The insulin signaling pathway interacts with different pathways and plays a core role in the regulations of all these processes. In this study, we reviewed recent studies on the relationship between the insulin signaling pathway and tumors using the Drosophila melanogaster model. We found that on one hand, the insulin pathway is normally hyperactive in tumor cells, which promotes tumor growth, and on the other hand, tumor cells can suppress the growth of healthy tissues via inhibition of their insulin pathway. Moreover, systematic disruption in glucose homeostasis also facilitates cancer development by different mechanisms. The studies on how the insulin network regulates the behaviors of cancer cells may help to discover new therapeutic treatments for cancer.

Evaluation of the inflammatory process, collagen production, and MMP-2 and MMP-9 expressions produced by Luffa aegyptiaca Mill using the subcutaneous rat implanted model

The subcutaneous rat implanted model is a preclinical approach used in studies to characterize the histocompatibility of materials that could be used as biomaterials. Biomaterials are obtained synthetically or from the environment, and they can be used to treat or replace any tissues or organs that the body has lost. To execute their roles, the biomaterials must present any level of histocompatibility and a lower level of inflammatory reaction. This work aimed to evaluate some aspects of histocompatibility, such as the inflammatory process, collagen production, and MMP-2 and 9 expression as responses to the Luffa aegyptiaca Mill using the subcutaneous rat implanted model. Luffa fragments were implanted into the dorsal subcutaneous region of twelve male Wistar rats, and the number of eosinophils, mast cells, the production of collagen to form the fibrous capsule, and the expression of MMP-2 and MMP-9 were evaluated on the 15th, 45th, and 90th days. Results showed statistical differences (p < 0.05) in the number of eosinophils and mast cells present inside and outside the fibrous capsule among the days evaluated. The permanent presence of macrophages and giant foreign body cells circumjacent to all implants was also observed. A progressive increase in the production of collagen was also detected, along with a significant reduction on day 90 (p < 0.05). The expression of MMP-9 was detected as being specifically expressed in the giant foreign body cells on all days evaluated, while the expression of MMP-2 was detected in fat cells present around the implants, mainly on day 90. Taken together, these results indicate a general reduction level for the inflammatory process during the days evaluated, which allows us to conclude that Luffa, being a natural product that is simple to obtain, could be a potential candidate to become a biomaterial to be tested in further approaches.

Adipose stem cells from type 2 diabetic mice exhibit therapeutic potential in wound healing

Background

Diabetic patients suffer from impaired wound healing. Mesenchymal stem cell (MSC) therapy represents a promising approach toward improving skin wound healing through the release of soluble growth factors and cytokines that stimulate new vessel formation and modulate inflammation. Whether adipose tissue-derived MSCs (ASCs) from type 2 diabetes (T2D) donors are suitable for skin damage repair remains largely unknown.

Methods

In this study, we compared the phenotype and functionality of ASCs harvested from high-fat diet (HFD) and streptozotocin (STZ)-induced T2D or control mice, and assessed their abilities to promote wound healing in an excisional wound splinting mouse model with T2D.

Results

T2D ASCs expressed similar cellular markers as control ASCs but secreted less hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), and transforming growth factor β (TGF-β). T2D ASCs were somewhat less effective in promoting healing of the wound, as manifested by slightly reduced re-epithelialization, cutaneous appendage regeneration, and collagen III deposition in wound tissues. In vitro, T2D ASCs promoted proliferation and migration of skin fibroblasts to a comparable extent as control ASCs via suppression of inflammation and macrophage infiltration.

Conclusions

From these findings, we conclude that, although ASCs from T2D mice are marginally inferior to control ASCs, they possess comparable therapeutic effects in wound healing.

Hypoxia Enhances Mesenchymal Characteristics Maintenance of Buffalo Bone Marrow-Derived Mesenchymal Stem Cells

Bone marrow-derived mesenchymal stem cells (BMSCs) from livestock are valuable resources for veterinary therapeutics and animal reproduction. Previous studies have shown that hypoxic conditions were beneficial in maintaining the mesenchymal feature of BMSCs. However, the effects of hypoxia on buffalo BMSCs (bBMSCs) remain unclear. In this study, the effects of hypoxic conditions on cell morphology, migration, polarity, and karyotype of bBMSCs were examined. The results showed that hypoxia (5% oxygen) enhanced colony formation and stress fiber synthesis of bBMSCs. Under the hypoxic culture conditions, the migration capacity and normal karyotype rate of bBMSCs were significantly improved (p < 0.05), which resulted in weakened cell polarity and enhanced karyotype stability in bBMSCs. In addition, it was significantly (p < 0.05) upregulated in the expression levels of HIF-TWIST signaling pathway axis-related genes (Hif-1, Hif-2, Twist, Snail, Slug, Fn1, N-cadherin, Collal). The HIF-TWIST axis of bBMSCs was also activated in hypoxia. Finally, it was more effective and easier to maintain the mesenchymal feature of bBMSCs in hypoxic conditions. These findings not only provide theoretical guidance to elucidate the detailed regulation mechanism of hypoxia on mesenchymal nature maintenance of bBMSCs, but also provide positive support to further establish the stable in vitro culture system of bBMSCs.

The NOTCH1-HEY1 pathway regulates self-renewal and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells

Our previous study demonstrated a close relationship between the NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). Its receptor gene, NOTCH1, and its downstream gene, HES1, contribute to the proliferation, invasion and metastasis of SACC. Accumulating evidence supports HEY1 as another effector of the signaling pathway. The purpose of this study was to explore the effects of the NOTCH1-HEY1 pathway on the proliferation, invasion and metastasis of SACC cells. Our results verified that HEY1 is a specific molecular target of the NOTCH signaling pathway in SACC cells and that its expression in carcinoma is much higher than that in paracarcinoma tissues. The expression of NOTCH1 and HEY1 are positively correlated in the salivary adenoid cystic carcinoma tissues. NOTCH1 is significantly related to the activation of HEY1 in SACC, and that HEY1 reciprocally regulates NOTCH1 expression in SACC. HEY1 promotes cell proliferation and spheroid formation and inhibits cell apoptosis in vitro. In addition, HEY1 enhances the tumorigenicity of SACC in vivo. Furthermore, HEY1 increases cell invasion and metastasis by driving the expression of epithelial-mesenchymal transition (EMT)-related genes and MMPs. The results of this study indicate that the NOTCH1-HEY1 pathway is specifically upregulated in SACC and promotes cell proliferation, self-renewal, invasion, metastasis and the expression of EMT-related genes and MMPs. Our findings suggest that a NOTCH1-HEY1 pathway inhibitor might therefore have potential therapeutic applications in treating SACC patients by inhibiting cancer cell growth and metastasis.

Human Adipose-Derived Hydrogel Characterization Based on In Vitro ASC Biocompatibility and Differentiation

Hydrogels serve as three-dimensional scaffolds whose composition can be customized to allow attachment and proliferation of several different cell types. Extracellular matrix-derived hydrogels are considered close replicates of the tissue microenvironment. They can serve as scaffolds for in vitro tissue engineering and are a useful tool to study cell-scaffold interaction. The aim of the present study was to analyze the effect of adipose-derived stromal/stem cells (ASCs) and decellularized adipose tissue-derived (DAT) hydrogel interaction on ASC morphology, proliferation, differentiation, and DAT hydrogel microstructure. First, the ASCs were characterized using flow cytometry, adipogenic/osteogenic differentiation, colony-forming unit fibroblast assay and doubling time. The viability and proliferation assays showed that ASCs seeded in DAT hydrogel at different concentrations and cultured for 21 days remained viable and displayed proliferation. ASCs were seeded on DAT hydrogel and cultured in stromal, adipogenic, or osteogenic media for 14 or 28 days. The analysis of adipogenic differentiation demonstrated the upregulation of adipogenic marker genes and accumulation of oil droplets in the cells. Osteogenic differentiation demonstrated the upregulation of osteogenic marker genes and mineral deposition in the DAT hydrogel. The analysis of DAT hydrogel fiber metrics revealed that ASC seeding, and differentiation altered both the diameter and arrangement of fibers in the matrix. Matrix metalloproteinase-2 (MMP-2) activity was assessed to determine the possible mechanism for DAT hydrogel remodeling. MMP-2 activity was observed in all ASC seeded samples, with the osteogenic samples displaying the highest MMP-2 activity. These findings indicate that DAT hydrogel is a cytocompatible scaffold that supports the adipogenic and osteogenic differentiation of ASCs. Furthermore, the attachment of ASCs and differentiation along adipogenic and osteogenic lineages remodels the microstructure of DAT hydrogel.

Articular cartilage regeneration: The role of endogenous mesenchymal stem/progenitor cell recruitment and migration

BACKGROUND

Trauma- or osteoarthritis-related cartilage damage resulted in functional decline of joints and heavy burden of public health. Recently, the reparative role of mesenchymal stem/progenitor cells (MSCs) in articular cartilage (AC) reconstruction is drawing more and more attention.

OBJECTIVE

To provide a review on (1) the locations and categories of joint-resident MSCs, (2) the regulation of chondrogenic capacities of MSCs, (3) the migratory approaches of MSCs to diseased AC and regulatory mechanisms.

METHODS

PubMed and Web of Science were searched for English-language articles related to MSC recruitment and migration for AC repair until June 2019. The presence of various MSCs in or around joints, the potential approaches to diseased AC` and the regenerative capacities of MSCs were reviewed.

RESULTS

Various intra- and peri-articular MSCs, with inherent migratory potentials, are present in multiple stem cell niches in or around joints. The recruitment and migration of joint-resident MSCs play crucial roles in endogenous AC repair. Multiple recruiting signals, such as chemokines, growth factors, etc., emerge during the development of AC diseases and participate in the regulation of MSC mobilization. Motivated MSCs could migrate into cartilage lesions and then exert multiple reparative potentials, including extracellular matrix (ECM) reconstruction and microenvironment modulation.

CONCLUSION

In general, AC repair based on endogenous MSC recruitment and migration is a feasible strategy, and a promising research field. Furthermore, endogenous AC repair mediated by native MSCs would provide new opportunities to efficient preventative or therapeutic options for AC diseases.

FER promotes cell migration via regulating JNK activity

Objectives

Cell migration has a key role in cancer metastasis, which contributes to drug resistance and tumour recurrence. Better understanding of the mechanisms involved in this process will potentially reveal new drug targets for cancer therapy. Fer is a non‐receptor protein tyrosine kinase aberrantly expressed in various human cancers, whereas its role in tumour progression remains elusive.

Materials and Methods

Transgenic flies and epigenetic analysis were employed to investigate the role of Drosophila Fer (FER) in cell migration and underlying mechanisms. Co‐immunoprecipitation assay was used to monitor the interaction between FER and Drosophila JNK (Bsk). The conservation of Fer in regulating JNK signalling was explored in mammalian cancer and non‐cancer cells.

Results

Overexpression of FER triggered cell migration and activated JNK signalling in the Drosophila wing disc. Upregulation and downregulation in the basal activity of Bsk exacerbated and eliminated FER‐mediated migration, respectively. In addition, loss of FER blocked signal transduction of the JNK pathway. Specifically, FER interacted with and promoted the activity of Bsk, which required both the kinase domain and the C‐terminal of Bsk. Lastly, Fer regulated JNK activities in mammalian cells.

Conclusions

Our study reveals FER as a positive regulator of JNK‐mediated cell migration and suggests its potential role as a therapeutic target for cancer metastasis.

In vivo articular cartilage regeneration through infrapatellar adipose tissue derived stem cell in nanofiber polycaprolactone scaffold

In this study, we report the development of a nanofiber polycaprolactone scaffold that can act as a stem cell carrier to induce chondrogenesis and promote cartilage repair in vivo. Infrapatellar fat pads were obtained from sheep knee and the stem cells were isolated and characterized by flow cytometry. Defects were created in sheep knee, two defects received adipose tissue derived stem cells (ASCs)-polycaprolactone construct, second group received polycaprolactone (PCL), the third group was chosen as the ASCs group and the fourth group was control group. Morphological evaluation showed that defects treated with ASCs-scaffold constructs were completely filled with cartilage-like tissue, while other groups revealed the formation of a thin layer of cartilage-like tissue in the defects. Real-Time RT-PCR showed the increase in collagen type 2 mRNA levels, aggrecan and Sox9 in ASCs/PCL groups in comparison with the other groups. Immunofluorescence and toluidine blue staining results showed the protein expression of collagen type 2 and formation of round and polygonal clusters of chondrocytes in ASCS/PCL group. According to our results nanofiber polycaprolactone promoted the chondrogenesis of infrapatellar adipose tissue derived stem cells in vivo and could offer significant promise in the biological functionality of stem cell tissue engineering in clinical practice.

Nucleic acids and analogs for bone regeneration

With the incidence of different bone diseases increasing, effective therapies are needed that coordinate a combination of various technologies and biological materials. Bone tissue engineering has also been considered as a promising strategy to repair various bone defects. Therefore, different biological materials that can promote stem cell proliferation, migration, and osteoblastic differentiation to accelerate bone tissue regeneration and repair have also become the focus of research in multiple fields. Stem cell therapy, biomaterial scaffolds, and biological growth factors have shown potential for bone tissue engineering; however, off-target effects and cytotoxicity have limited their clinical use. The application of nucleic acids (deoxyribonucleic acid or ribonucleic acid) and nucleic acid analogs (peptide nucleic acids or locked nucleic acids), which are designed based on foreign genes or with special structures, can be taken up by target cells to exert different effects such as modulating protein expression, replacing a missing gene, or targeting specific gens or proteins. Due to some drawbacks, nucleic acids and nucleic acid analogs are combined with various delivery systems to exert enhanced effects, but current studies of these molecules have not yet satisfied clinical requirements. In-depth studies of nucleic acid or nucleic acid analog delivery systems have been performed, with a particular focus on bone tissue regeneration and repair. In this review, we mainly introduce delivery systems for nucleic acids and nucleic acid analogs and their applications in bone repair and regeneration. At the same time, the application of conventional scaffold materials for the delivery of nucleic acids and nucleic acid analogs is also discussed.

Used with an appropriate delivery system, nucleic acids and nucleic acid analogs have excellent potential for bone repair and regeneration. Owing to various challenges with bone tissue regeneration, current research is largely focused on gene therapy, which employs genes to treat or prevent disease, and such new materials as nucleic acids (DNA and RNA) and nucleic acid analogs (compounds structurally similar to naturally occurring nucleic acids). A team headed by Yunfeng Lin at Sichuan University, China conducted a review of delivery systems for nucleic acids and nucleic acid analogs and their application in bone repair and regeneration. The authors identified the use of biomaterial scaffolds (which mimic living tissue) as one of the most important research areas for gene therapy, and that strategy has proven effective with all types of bone regeneration and repair.

Polarity protein Canoe mediates overproliferation via modulation of JNK, Ras-MAPK and Hippo signalling

Objectives

Over the past decade an intriguing connection between cell polarity and tumorigenesis has emerged. Multiple core components of the junction complexes that help to form and maintain cell polarity display both pro‐ and anti‐tumorigenic functions in a context‐dependent manner, with the underlying mechanisms poorly understood.

Materials and Methods

With transgenic fly lines that overexpress or knock down specific signalling components, we perform genetic analysis to investigate the precise role of the polarity protein Canoe (Cno) in tumorigenesis and the downstream pathways.

Results

We show that overexpression of cno simultaneously activates JNK and Ras‐MEK‐ERK signalling, resulting in mixed phenotypes of both overproliferation and cell death in the Drosophila wing disc. Moderate alleviation of JNK activation eliminates the effect of Cno on cell death, leading to organ overgrowth and cell migration that mimic the formation and invasion of tumours. In addition, we find that the Hippo pathway acts downstream of JNK and Ras signalling to mediate the effect of Cno on cell proliferation.

Conclusions

Our work reveals an oncogenic role of Cno and creates a new type of Drosophila tumour model for cancer research.

Inhibiting Methicillin-Resistant Staphylococcus aureus by Tetrahedral DNA Nanostructure-Enabled Antisense Peptide Nucleic Acid Delivery

One of the biggest obstacles for the use of antisense oligonucleotides as antibacterial therapeutics is their limited uptake by bacterial cells without a suitable carrier, especially in multi-drug-resistant bacteria with a drug efflux mechanism. Existing vectors, such as cell-penetrating peptides, are inefficient and nontargeting, and accordingly are not ideal carriers. A noncytotoxic tetrahedral DNA nanostructure (TDN) with a controllable conformation has been developed as a delivery vehicle for antisense oligonucleotides. In this study, antisense peptide nucleic acids (asPNAs) targeting a specific gene ( ftsZ) were efficiently transported into methicillin-resistant Staphylococcus aureus cells by TDNs, and the expression of ftsZ was successfully inhibited in an asPNA-concentration-dependent manner. The delivery system specifically targeted the intended gene. This novel delivery system provides a better platform for future applications of antisense antibacterial therapeutics and provides a basis for the development of a new type of antibacterial drug for multi-drug-resistant bacterial infections.

MMP-2 and Notch signal pathway regulate migration of adipose-derived stem cells and chondrocytes in co-culture systems

OBJECTIVES

The crosstalk between chondrocytes and adipose-derived stem cells (ADSCs) could regulate the secretion of multiple growth factors. However, it is not clear how the paracrine action in co-culture systems affect cell migration. This study focused on the changes of cell migration of ADSCs and chondrocytes in co-culture conditions.

MATERIALS AND METHODS

Primary ADSCs and chondrocytes were isolated from Sprague-Dawley rat. Transwell co-culture systems, inoculated with ADSCs and chondrocytes, were established in vitro. The morphology of the cells was observed 7 days post-seeding by inverted phase-contrast microscope. Additionally, the cytoskeleton changes were investigated by immunofluorescence staining. To detect the abundance of Vinculin, we used immunofluorescence and Western blotting. Additionally, the expression level of MMP-2, Hey1 and Hes1 was examined to determine the mechanisms of co-culture-induced cell migration changes.

RESULTS

The migration of ADSCs and chondrocytes in co-culture conditions significantly decreased compared with that in mono-culture groups, accompanied by the decrease of filopodia and the expression level of MMP-2.

CONCLUSIONS

The overall study showed that the migration of ADSCs and chondrocytes differs significantly depending on culture conditions. Moreover, the Notch signalling pathway may be involved in this process. Accordingly, by studying changes in migration caused by co-culture, we obtained new insight into the crosstalk between ADSCs and chondrocytes.