TGIF1 Gene Silencing in Tendon-Derived Stem Cells Improves the Tendon-to-Bone Insertion Site Regeneration

Background/Aims: The slow healing process of tendon-to-bone junctions can be accelerated via implanted tendon-derived stem cells (TDSCs) with silenced transforming growth interacting factor 1 (TGIF1) gene. Tendon-to-bone insertion site is the special form of connective tissues derivatives of common connective progenitors, where TGF-β plays bidirectional effects (chondrogenic or fibrogenic) through different signaling pathways at different stages. A recent study revealed that TGF-β directly induces the chondrogenic gene Sox9. However, TGIF1 represses the expression of the cartilage master Sox9 gene and changes its expression rate against the fibrogenesis gene Scleraxis (Scx). Methods: TGIF1 siRNA was transduced or TGIF1 was over-expressed in tendon-derived stem cells. Following suprapinatus tendon repair, rats were either treated with transduced TDSCs or nontransduced TDSCs. Histologic examination and Western blot were performed in both groups. Results: In this study, the silencing of TGIF1 significantly upregulated the chondrogenic genes and markers. Similarly, TGIF1 inhibited TDSC differentiation into cartilage via interactions with TGF-β-activated Smad2 and suppressed the phosphorylation of Smad2. The area of fibrocartilage at the tendon-bone interface was significantly increased in the TGIF1 (-) group compared with the control and TGIF1-overexpressing groups in the early stages of the animal model. The interface between the tendon and bone showed a increase of new bone and fibrocartilage in the TGIF1 (-) group at 4 weeks. Fibrovascular scar tissue was observed in the TGIF1-overexpressing group and the fibrin glue only group. Low levels of fibrocartilage and fibrovascular scar tissue were found in the TDSCs group. Conclusion: Collectively, this study shows that the tendon-derived stem cell modified with TGIF1 gene silencing has promising effects on tendon-to-bone healing which can be further explored as a therapeutic tool in regenerative medicine.

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Application of ADSCs and their Exosomes in Scar Prevention

Stem Cell Reviews and Reports ◽

10.1007/s12015-021-10252-5 ◽

2021 ◽

Author(s):

Cong Li ◽

Shuqiang Wei ◽

Quanchen Xu ◽

Yu Sun ◽

Xuchao Ning ◽

...

Keyword(s):

Stem Cells ◽

Wound Healing ◽

Adipose Tissue ◽

Tissue Injury ◽

Healing Process ◽

Treatment Method ◽

Scar Tissue ◽

Wound Healing Process ◽

Target Cells ◽

Cellular Components

AbstractScar is a common way of healing after tissue injury. The poor scar healing will not only cause dysfunction of tissues and organs but also affect the appearance of the patients’ body surface, which causes the pressure of life and spirit to the patients. However, the formation of scar tissue is an extremely complex process and its mechanism is not fully understood. At present, there is no treatment method to eliminate scars completely. Fibroblasts are the most abundant cells in the dermis, which have the ability to synthesize and remodel extracellular matrix (ECM). Myofibroblasts actively participate in the wound healing process and influence the outcome. Therefore, both of them play important roles in wound healing and scar formation. Adipose tissue-derived stem cells (ADSCs) are pluripotent stem cells that can act on target cells by paracrine. Adipose tissue stem cell-derived exosomes (ADSC-Exos) are important secretory substances of ADSCs. They are nanomembrane vesicles that can transport a variety of cellular components and fuse with target cells. In this review, we will discuss the effects of ADSCs and ADSC-Exos on the behavior of fibroblasts and myofibroblasts during wound healing and scarring stage in combination with recent studies. Graphical Abstract

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Stem Cells for Augmenting Tendon Repair

Stem Cells International ◽

10.1155/2012/291431 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 28

Author(s):

Lawrence V. Gulotta ◽

Salma Chaudhury ◽

Daniel Wiznia

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Growth Factors ◽

Adhesion Formation ◽

Tendon Repair ◽

Tendon Healing ◽

Scar Tissue ◽

Mechanical Stimuli ◽

Injury Site ◽

Attractive Option

Tendon healing is fraught with complications such as reruptures and adhesion formation due to the formation of scar tissue at the injury site as opposed to the regeneration of native tissue. Stem cells are an attractive option in developing cell-based therapies to improve tendon healing. However, several questions remain to be answered before stem cells can be used clinically. Specifically, the type of stem cell, the amount of cells, and the proper combination of growth factors or mechanical stimuli to induce differentiation all remain to be seen. This paper outlines the current literature on the use of stem cells for tendon augmentation.

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Injured Achilles Tendons Treated with Adipose-Derived Stem Cells Transplantation and GDF-5

Cells ◽

10.3390/cells7090127 ◽

2018 ◽

Vol 7 (9) ◽

pp. 127 ◽

Cited By ~ 15

Author(s):

Andrea de Aro ◽

Giane Carneiro ◽

Luis Teodoro ◽

Fernanda da Veiga ◽

Danilo Ferrucci ◽

...

Keyword(s):

Stem Cells ◽

Collagen Fiber ◽

Healing Process ◽

Tendon Repair ◽

Repair Process ◽

Tendon Injuries ◽

Vitro Assay ◽

Genes Expression ◽

Fiber Organization

Tendon injuries represent a clinical challenge in regenerative medicine because their natural repair process is complex and inefficient. The high incidence of tendon injuries is frequently associated with sports practice, aging, tendinopathies, hypertension, diabetes mellitus, and the use of corticosteroids. The growing interest of scientists in using adipose-derived mesenchymal stem cells (ADMSC) in repair processes seems to be mostly due to their paracrine and immunomodulatory effects in stimulating specific cellular events. ADMSC activity can be influenced by GDF-5, which has been successfully used to drive tenogenic differentiation of ADMSC in vitro. Thus, we hypothesized that the application of ADMSC in isolation or in association with GDF-5 could improve Achilles tendon repair through the regulation of important remodeling genes expression. Lewis rats had tendons distributed in four groups: Transected (T), transected and treated with ADMSC (ASC) or GDF-5 (GDF5), or with both (ASC+GDF5). In the characterization of cells before application, ADMSC expressed the positive surface markers, CD90 (90%) and CD105 (95%), and the negative marker, CD45 (7%). ADMSC were also differentiated in chondrocytes, osteoblast, and adipocytes. On the 14th day after the tendon injury, GFP-ADMSC were observed in the transected region of tendons in the ASC and ASC+GDF5 groups, and exhibited and/or stimulated a similar genes expression profile when compared to the in vitro assay. ADMSC up-regulated Lox, Dcn, and Tgfb1 genes expression in comparison to T and ASC+GDF5 groups, which contributed to a lower proteoglycans arrangement, and to a higher collagen fiber organization and tendon biomechanics in the ASC group. The application of ADMSC in association with GDF-5 down-regulated Dcn, Gdf5, Lox, Tgfb1, Mmp2, and Timp2 genes expression, which contributed to a lower hydroxyproline concentration, lower collagen fiber organization, and to an improvement of the rats’ gait 24 h after the injury. In conclusion, although the literature describes the benefic effect of GDF-5 for the tendon healing process, our results show that its application, isolated or associated with ADMSC, cannot improve the repair process of partial transected tendons, indicating the higher effectiveness of the application of ADMSC in injured Achilles tendons. Our results show that the application of ADMSC in injured Achilles tendons was more effective in relation to its association with GDF-5.

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Pseudotendon: Ultrastructural Similarities to Scar Development

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002051 ◽

1980 ◽

Vol 38 ◽

pp. 474-475

Author(s):

C.W. Kischer ◽

A.J. Arem

Keyword(s):

Hypertrophic Scar ◽

Healing Process ◽

Tendon Repair ◽

Scar Tissue ◽

Collagen Remodeling ◽

Regeneration Of Skin

Pseudotendon is a remarkable attempt to reform a working, gliding, unit of organized collagen in the wake of tendon transection. Tension forces transmitted from the severed muscle-tendon unit through the newly forming scar may organize the collagen into a functional configuration. The dynamics of collagen remodeling appear precise and orderly, and excess collagen is not built up as it is in the case of hypertrophic scar1. Since tendon repair and regeneration of skin each involve formation of scar tissue, but, since the former process is abbreviated and the latter is prolonged a comparison of the two cases with respect to scar production seems beneficial. The ultrastructural character of each may show significant differences which could account for the different fates of each healing process.

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Faculty Opinions recommendation of Transgenesis by lentiviral vectors: lack of gene silencing in mammalian embryonic stem cells and preimplantation embryos.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1005535.65959 ◽

2002 ◽

Author(s):

Casey Weaver

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Gene Silencing ◽

Embryonic Stem ◽

Lentiviral Vectors ◽

Preimplantation Embryos

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330. Genetic Modification of Murine Embryonic Stem Cells by the Gene Silencing Resistance Retroviral Vector GCDsap

Molecular Therapy ◽

10.1016/j.ymthe.2004.06.272 ◽

2004 ◽

Vol 9 ◽

pp. S125

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Gene Silencing ◽

Genetic Modification ◽

Embryonic Stem ◽

Retroviral Vector ◽

Murine Embryonic Stem Cells

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Mesenchymal Stem Cells after Polytrauma: Actor and Target

Stem Cells International ◽

10.1155/2016/6289825 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Markus Huber-Lang ◽

Rebecca Wiegner ◽

Lorenz Lampl ◽

Rolf E. Brenner

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Healing Process ◽

Severe Trauma ◽

Signaling Mechanisms ◽

Multipotent Cells ◽

Proliferation And Differentiation ◽

Tissue Trauma ◽

Molecular Patterns ◽

Severe Tissue

Mesenchymal stem cells (MSCs) are multipotent cells that are considered indispensable in regeneration processes after tissue trauma. MSCs are recruited to damaged areas via several chemoattractant pathways where they function as “actors” in the healing process by the secretion of manifold pro- and anti-inflammatory, antimicrobial, pro- and anticoagulatory, and trophic/angiogenic factors, but also by proliferation and differentiation into the required cells. On the other hand, MSCs represent “targets” during the pathophysiological conditions after severe trauma, when excessively generated inflammatory mediators, complement activation factors, and damage- and pathogen-associated molecular patterns challenge MSCs and alter their functionality. This in turn leads to complement opsonization, lysis, clearance by macrophages, and reduced migratory and regenerative abilities which culminate in impaired tissue repair. We summarize relevant cellular and signaling mechanisms and provide an up-to-date overview about promising future therapeutic MSC strategies in the context of severe tissue trauma.

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Characterization of scar tissue biomechanics during adult murine flexor tendon healing

10.1101/2021.11.09.467960 ◽

2021 ◽

Author(s):

Antonion Korcari ◽

Alayna E Loiselle ◽

Mark R Buckley

Keyword(s):

Mechanical Properties ◽

Material Properties ◽

Healing Process ◽

Tendon Healing ◽

Scar Tissue ◽

Element Analysis ◽

Material Quality ◽

Treatment Regimens ◽

Tangent Moduli ◽

Experimental Findings

Tendon injuries are very common and result in significant impairments in mobility and quality of life. During healing, tendons produce a scar at the injury site, characterized by abundant and disorganized extracellular matrix and by permanent deficits in mechanical integrity compared to healthy tendon. Although a significant amount of work has been done to understand the healing process of tendons and to develop potential therapeutics for tendon regeneration, there is still a significant gap in terms of assessing the direct effects of therapeutics on the functional and material quality specifically of the scar tissue, and thus, on the overall tendon healing process. In this study, we focused on characterizing the mechanical properties of only the scar tissue in flexor digitorum longus (FDL) tendons during the proliferative and remodeling healing phases and comparing these properties with the mechanical properties of the composite healing tissue. Our method was sensitive enough to identify significant differences in structural and material properties between the scar and tendon-scar composite tissues. To account for possible inaccuracies due to the small aspect ratio of scar tissue, we also applied inverse finite element analysis (iFEA) to compute mechanical properties based on simulated tests with accurate specimen geometries and boundary conditions. We found that the scar tissue linear tangent moduli calculated from iFEA were not significantly different from those calculated experimentally at all healing timepoints, validating our experimental findings, and suggesting the assumptions in our experimental calculations were accurate. Taken together, this study first demonstrates that due to the presence of uninjured stubs, testing composite healing tendons without isolating the scar tissue overestimates the material properties of the scar itself. Second, our scar isolation method promises to enable more direct assessment of how different treatment regimens (e.g., cellular ablation, biomechanical and/or biochemical stimuli, tissue engineered scaffolds) affect scar tissue function and material quality in multiple different types of tendons.

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Clumps of Mesenchymal Stem Cells/Extracellular Matrix Complexes Generated with Xeno-Free Chondro-Inductive Medium induce Bone Regeneration via Endochondral Ossification

Biomedicines ◽

10.3390/biomedicines9101408 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1408

Author(s):

Susumu Horikoshi ◽

Mikihito Kajiya ◽

Souta Motoike ◽

Mai Yoshino ◽

Shin Morimoto ◽

...

Keyword(s):

Stem Cells ◽

Extracellular Matrix ◽

Mesenchymal Stem Cells ◽

Bone Formation ◽

Bone Regeneration ◽

Endochondral Ossification ◽

Healing Process ◽

Early Period ◽

Cartilage Matrix

Three-dimensional clumps of mesenchymal stem cells (MSCs)/extracellular matrix (ECM) complexes (C-MSCs) can be transplanted into tissue defect site with no artificial scaffold. Importantly, most bone formation in the developing process or fracture healing proceeds via endochondral ossification. Accordingly, this present study investigated whether C-MSCs generated with chondro-inductive medium (CIM) can induce successful bone regeneration and assessed its healing process. Human bone marrow-derived MSCs were cultured with xeno-free/serum-free (XF) growth medium. To obtain C-MSCs, confluent cells that had formed on the cellular sheet were scratched using a micropipette tip and then torn off. The sheet was rolled to make a round clump of cells. The cell clumps, i.e., C-MSCs, were maintained in XF-CIM. C-MSCs generated with XF-CIM showed enlarged round cells, cartilage matrix, and hypertrophic chondrocytes genes elevation in vitro. Transplantation of C-MSCs generated with XF-CIM induced successful bone regeneration in the SCID mouse calvaria defect model. Immunofluorescence staining for human-specific vimentin demonstrated that donor human and host mouse cells cooperatively contributed the bone formation. Besides, the replacement of the cartilage matrix into bone was observed in the early period. These findings suggested that cartilaginous C-MSCs generated with XF-CIM can induce bone regeneration via endochondral ossification.

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