Amniotic membrane stimulates cell migration by modulating Transforming Growth Factor-β signaling (original) (raw)
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Frontiers in Bioengineering and Biotechnology, 2021
The application of amniotic membrane (AM) on chronic wounds has proven very effective at resetting wound healing, particularly in re-epithelialization. Historically, several aspects of AM effect on wound healing have been evaluated using cell models. In keratinocytes, the presence of AM induces the activation of mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK) pathways, together with the high expression of c-Jun, an important transcription factor for the progression of the re-epithelialization tongue. In general, the levels of transforming growth factor (TGF)-β present in a wound are critical for the process of wound healing; they are elevated during the inflammation phase and remain high in some chronic wounds. Interestingly, the presence of AM, through epidermal growth factor (EGF) signaling, produces a fine-tuning of the TGF-β signaling pathway that re-conducts the stalled process of wound healing. However, the complete suppression of TGF-β signaling has p...
International Journal of Molecular Sciences
Unsuccessful wound closure in chronic wounds can be linked to altered keratinocyte activation and their inability to re-epithelize. Suggested mechanisms driving this impairment involve unbalanced cytokine signaling. However, the molecular events leading to these aberrant responses are poorly understood. Among cytokines affecting keratinocyte responses, Transforming Growth Factor-β (TFG-β) is thought to have a great impact. In this study, we have used a previously characterized skin epidermal in vitro model, HaCaT cells continuously exposed to TGF-β1, to study the wound recovery capabilities of chronified/senescent keratinocytes. In this setting, chronified keratinocytes show decreased migration and reduced activation in response to injury. Amniotic membrane (AM) has been used successfully to manage unresponsive complicated wounds. In our in vitro setting, AM treatment of chronified keratinocytes re-enabled migration in the early stages of wound healing, also promoting proliferation ...
PLOS ONE, 2015
Background Post-traumatic large-surface or deep wounds often cannot progress to reepithelialisation because they become irresponsive in the inflammatory stage, so intervention is necessary to provide the final sealing epidermis. Previously we have shown that Amniotic Membrane (AM) induced a robust epithelialisation in deep traumatic wounds. Methods and Findings To better understand this phenomenon, we used keratinocytes to investigate the effect of AM on chronic wounds. Using keratinocytes, we saw that AM treatment is able to exert an attenuating effect upon Smad2 and Smad3 TGFß-induced phosphorylation while triggering the activation of several MAPK signalling pathways, including ERK and JNK1, 2. This also has a consequence for TGFß-induced regulation on cell cycle control key players CDK1A (p21) and CDK2B (p15). The study of a wider set of TGFß regulated genes showed that the effect of AM was not wide but very concrete for some genes. TGFß exerted a powerful cell cycle arrest; the presence of AM however prevented TGFß-induced cell cycle arrest. Moreover, AM induced a powerful cell migration response that correlates well with the expression of c-Jun protein at the border of the healing assay. Consistently, the treatment with AM of human chronic wounds induced a robust expression of c-Jun at the wound border. Conclusions The effect of AM on the modulation of TGFß responses in keratinocytes that favours proliferation together with AM-induced keratinocyte migration is the perfect match that allows chronic wounds to move on from their non-healing state and progress into epithelialization.
The Use of Amniotic Membrane in the Management of Complex Chronic Wounds
Wound Healing - New insights into Ancient Challenges, 2016
Chronic wounds do not follow the usual wound healing process; instead, they are stuck in the inflammatory or proliferative phase. This is particularly evident in large, massive wounds with considerable tissue loss, which become senescent and do not epithelialize. In these wounds, we need to remove all the factors that prevent or delay normal wound healing. After that, soft tissue granulation is stimulated by local negative pressure therapy. Lastly, after the granulation is completed, the epithelialization process must be activated. Although a plethora of wound dressings and devices are available, chronic wounds persist as a unresolved medical concern. We have been using frozen amniotic membrane (AM) to treat this type of wounds with good results. Our studies have shown that AM is able to induce epithelialization in large wounds that were unable to epithelialize. AM induces several signaling pathways involved in cell migration and/or proliferation. Among those, we can highlight the mitogen-activated protein kinase (MAPK) and Jun N-terminal kinase (JNK) signaling pathways. Additionally, AM is able to selectively antagonise the anti-proliferative effect of TGFß by modifying its genetic program on keratinocytes. The combined effect of AM on keratinocytes, promoting cell proliferation/migration and antagonising TGFß-effect, is the perfect combination allowing chronic wounds to progress into epithelialization.
Amniotic membrane induces epithelialization in massive posttraumatic wounds
Wound Repair and Regeneration, 2010
Large-surface or deep wounds often become senescent in the inflammatory or proliferation stages and cannot progress to reepithelialization. This failure makes intervention necessary to provide the final sealing epithelial layer. The best current treatment is autologous skin graft, although there are other choices such as allogenic or autologous skin substitutes and synthetic dressings. Amniotic membrane (AM) is a tissue of interest as a biological dressing due to its biological properties and immunologic characteristics. It has low immunogenicity and beneficial reepithelialization effects, with antiinflammatory, antifibrotic, antimicrobial, and nontumorigenic properties. These properties are related to its capacity to synthesize and release cytokines and growth factors. We report the use of AM as a wound dressing in two patients with large and deep traumatic wounds. Negative pressure wound therapy followed by AM application was capable of restoring skin integrity avoiding the need for skin graft reconstruction. AM induced the formation of a well-structured epidermis. To understand this effect, we designed some assays on human keratinocyte-derived HaCaT cells. AM treatment of HaCaT induced ERK1/2 and SAP/JNK kinases phosphorylation and c-jun expression, a gene critical for keratinocytes migration; however, it did not affect cell cycle distribution. These data suggest that AM substantially modifies the behavior of keratinocytes in chronic wounds, thereby allowing effective reepithelialization.
Amniotic membrane promotes focal adhesion remodeling to stimulate cell migration
Scientific reports, 2017
During wound healing, the migration of keratinocytes onto newly restored extracellular matrix aims to reestablish continuity of the epidermis. The application of amniotic membrane (AM) to chronic, deep traumatic, non-healing wounds has proven successful at stimulating re-epithelialization. When applied on epithelial cell cultures, AM activates extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinases 1/2 (JNK1/2), with the overexpression and phosphorylation of c-Jun along the wound edge. The effect of AM on the migration of cells was investigated by studying critical proteins involved in the focal adhesions turn-over: Focal Adhesion Kinase (FAK), Paxillin and Vinculin. In Mv1Lu and HaCaT cells, validated models for cell migration and wound healing, AM affected the expression and activation of Paxillin, but did not affect Vinculin expression, both factors which integrate into focal adhesions. Moreover, AM regulation also affected FAK activity through phosphoryl...
Effects of amniotic fluid on human keratinocyte gene expression: Implications for wound healing
Experimental Dermatology, 2022
Cutaneous wound healing is a clinically important field of research where the translation of new treatment options is desperately needed. The healing process involves innate and adaptive immunity. Blood factors and all the cells and compartments of the integumentary system compromise a complex structure that presents many potential targets for intervention. Inflammatory cascades and the re-establishment of epithelial integrity marks the early phase of cutaneous wound healing whilst tissue remodelling and the return of further skin functions occur at later stages of the healing process. 1 The realisation that early fetal wounds heal with tissue regeneration instead of scarring suggests an instructive role of the embryonic environment in regulating the response to wounding. 2 The
Wound Healing - New insights into Ancient Challenges
InTech eBooks, 2016
Chronic wounds do not follow the usual wound healing process; instead, they are stuck in the inflammatory or proliferative phase. This is particularly evident in large, massive wounds with considerable tissue loss, which become senescent and do not epithelialize. In these wounds, we need to remove all the factors that prevent or delay normal wound healing. After that, soft tissue granulation is stimulated by local negative pressure therapy. Lastly, after the granulation is completed, the epithelialization process must be activated. Although a plethora of wound dressings and devices are available, chronic wounds persist as a unresolved medical concern. We have been using frozen amniotic membrane (AM) to treat this type of wounds with good results. Our studies have shown that AM is able to induce epithelialization in large wounds that were unable to epithelialize. AM induces several signaling pathways involved in cell migration and/or proliferation. Among those, we can highlight the mitogen-activated protein kinase (MAPK) and Jun N-terminal kinase (JNK) signaling pathways. Additionally, AM is able to selectively antagonise the anti-proliferative effect of TGFß by modifying its genetic program on keratinocytes. The combined effect of AM on keratinocytes, promoting cell proliferation/migration and antagonising TGFß-effect, is the perfect combination allowing chronic wounds to progress into epithelialization.
Dermal Transforming Growth Factor-β Responsiveness Mediates Wound Contraction and Epithelial Closure
The American Journal of Pathology, 2010
Stromal-epithelial interactions are important during wound healing. Transforming growth factor- (TGF-) signaling at the wound site has been implicated in re-epithelization , inflammatory infiltration, wound contraction , and extracellular matrix deposition and remodeling. Ultimately , TGF- is central to dermal scarring. Because scarless embryonic wounds are associated with the lack of dermal TGF- signaling , we studied the role of TGF- signaling specifically in dermal fibroblasts through the development of a novel , inducible , conditional , and fibroblastic TGF- type II receptor knockout (Tgfbr2 dermalKO) mouse model. Full thickness excisional wounds were studied in control and Tgfbr2 dermalKO back skin. The Tgfbr2 dermalKO wounds had accelerated re-epithelization and closure compared with controls , resurfacing within 4 days of healing. The loss of TGF- signaling in the dermis resulted in reduced collagen deposition and remodeling associated with a reduced extent of wound contraction and elevated macrophage infiltration. Tgfbr2 dermalKO and control skin had similar numbers of myofibroblastic cells , suggesting that myofibroblastic differentiation was not responsible for reduced wound contraction. However , several mediators of cell-matrix interaction were reduced in the Tgfbr2 dermalKO fibroblasts , including ␣1 , ␣2 , and 1 integrins , and collagen gel contraction was diminished. There were associated deficiencies in actin cytoskeletal organization of vasodilatorstimulated phosphoprotein-containing lamellipo-dia. This study indicated that paracrine and autocrine TGF- dermal signaling mechanisms mediate macrophage recruitment , re-epithelization , and wound contraction.