Integrin-mediated regulation of epidermal wound functions

Loss of ADAM29 does not affect viability and fertility in mice but improves wound healing

ADAM29 (a disintegrin and metalloprotease domain 29) is a member of the membrane-anchored ADAM family of proteins, which is highly expressed in testis and may mediate different physiological and pathological processes. Although the functions of many ADAM family members have been well characterized, the biological relevance of ADAM29 has remained largely unknown. Here, we report the generation of an Adam29-deficient mouse model to delve deeper into the in vivo functions of this ADAM family member. We show that ADAM29 depletion does not affect mice viability, development, or fertility, but somehow impinges on metabolism and energy expenditure. We also report herein that ADAM29 deficiency leads to an accelerated wound healing process, without affecting cell reprogramming in mouse-derived fibroblasts. Collectively, our findings provide new insights into ADAM29 biological functions, highlighting the importance of non-catalytic ADAM proteases.

Roles for epithelial integrin α3β1 in regulation of the microenvironment during normal and pathological tissue remodeling

Integrin receptors for the extracellular matrix activate intracellular signaling pathways that are critical for tissue development, homeostasis, and regeneration/repair, and their loss or dysregulation contributes to many developmental defects and tissue pathologies. This review will focus on tissue remodeling roles for integrin α3β1, a receptor for laminins found in the basement membranes (BMs) that underlie epithelial cell layers. As a paradigm, we will discuss literature that supports a role for α3β1 in promoting ability of epidermal keratinocytes to modify their tissue microenvironment during skin development, wound healing, or tumorigenesis. Preclinical and clinical studies have shown that this role depends largely on ability of α3β1 to govern the keratinocyte's repertoire of secreted proteins, or the "secretome," including 1) matrix proteins and proteases involved in matrix remodeling and 2) paracrine-acting growth factors/cytokines that stimulate other cells with important tissue remodeling functions (e.g., endothelial cells, fibroblasts, inflammatory cells). Moreover, α3β1 signaling controls gene expression that helps epithelial cells carry out these functions, including genes that encode secreted matrix proteins, proteases, growth factors, or cytokines. We will review what is known about α3β1-dependent gene regulation through both transcription and posttranscriptional mRNA stability. Regarding the latter, we will discuss examples of α3β1-dependent alternative splicing (AS) or alternative polyadenylation (APA) that prevents inclusion of cis-acting mRNA sequences that would otherwise target the transcript for degradation via nonsense-mediated decay or destabilizing AU-rich elements (AREs) in the 3'-untranslated region (3'-UTR). Finally, we will discuss prospects and anticipated challenges of exploiting α3β1 as a clinical target for the treatment of cancer or wound healing.

Construction of chitosan-gelatin polysaccharide-protein composite hydrogel via mechanical stretching and its biocompatibility in vivo

Natural polysaccharides and protein macromolecules are the important components of extracellular matrix (ECM), but individual component generally exhibits weak mechanical property, limited biological function or strong immunogenicity in tissue engineering. Herein, gelatin (Gel) was deposited to the stretched (65 %) chitosan (CS) hydrogel substrates to fabricate the polysaccharide-protein CS-Gel-65 % composite hydrogels to mimic the natural component of ECM and improve the above deficiencies. CS hydrogel substrates under different stretching deformations exhibited tunable morphology, chemical property and wettability, having a vital influence on the secondary structures of deposited fibrous Gel protein, namely appearing with the decreased β-sheet content in stretched CS hydrogel. Gel also produced a more homogenous distribution on the stretched CS hydrogel substrate due to the unfolding of Gel and increased interactions between Gel and CS than on the unstretched substrate. Moreover, the polysaccharide-protein composite hydrogel possessed enhanced mechanical property and oriented structure via stretching-drying method. Besides, in vivo subcutaneous implantation indicated that the CS-Gel-65 % composite hydrogel showed lower immunogenicity, thinner fibrous capsule, better angiogenesis effect and increased M2/M1 of macrophage phenotype. Polysaccharide-protein CS-Gel-65 % composite hydrogel offers a novel material as a tissue engineering scaffold, which could promote angiogenesis and build a good immune microenvironment for the damaged tissue repair.

Lespedeza maximowiczii flower absolute promotes skin epithelization, barrier properties, and moisturization-related beneficial responses in human keratinocytes

Lespedeza maximowiczii (LM), a member of the legume family, has tyrosinase inhibitory and estrogenic activities. However, its effects on skin-related biological activities remain unclear. Therefore, the present study aimed to explore the effects of LM flower absolute (LMFAb) on skin-related biological events, especially skin re-epithelization, barrier and moisturizing-related keratinocyte (HaCaT cell) responses. In this study, LMFAb was isolated from LM flowers via solvent extraction and its chemical composition analysis was performed using gas chromatography/mass spectrometry. 5-bromo-2'-deoxyuridine incorporation, Boyden chamber, sprout outgrowth, enzyme-linked immunosorbent, and Western blot assay were used to analyze the biological effects of LMFAb on HaCaT cells (a human epidermal keratinocyte cell line). Twelve components were identified in LMFAb. LMFAb promoted cell proliferation, migration, and sprout outgrowth in HaCaT cells. The absolute enhanced the activations of MAPKs (ERK1/2, JNK, and p38), PI3K and AKT proteins in HaCaT cells and elevated collagen type I and IV levels in HaCaT cell conditioned medium. In addition, LMFAb induced an increase in the expression levels of epidermal barrier proteins (filaggrin and involucrin) in HaCaT cells. Furthermore, LMFAb increased hyaluronan (HA) production and expression of HA synthases (HAS-1, HAS-2, and HAS-3) but decreased HYBID (HA binding protein involved in HA depolymerization) level in HaCaT cells. These findings demonstrate that LMFAb might promote skin re-epithelization, barrier and moisturizing-related beneficial responses in keratinocytes. This study suggests that LMFAb should be considered a potential starting material for the development of cosmetic or pharmaceutical agents that restore the functions of damaged skin.

Roxithromycin and rhEGF Co-loaded Reactive Oxygen Species Responsive Nanoparticles for Accelerating Wound Healing

BACKGROUND

Bacterial infection can delay wound healing and is therefore a major threat to public health. Although various strategies have been developed to treat bacterial infections, antibiotics remain the best option to combat infections. The inclusion of growth factors in the treatment approach can also accelerate wound healing. The co-delivery of antibiotics and growth factors for the combined treatment of wounds needs further investigation.

OBJECTIVE

Here we aimed to develop antibiotic and growth factor co-loaded nanoparticles (NPs) to treat Staphylococcus aureus-infected wounds.

METHODS

By using our previously prepared reactive oxygen species-responsive material (Oxi-αCD), roxithromycin (ROX)-loaded NPs (ROX/Oxi-αCD NPs) and recombinant human epidermal growth factor (rhEGF)/ROX co-loaded NPs (rhEGF/ROX/Oxi-αCD NPs) were successfully fabricated. The in vivo efficacy of this prepared nanomedicine was evaluated in mice with S. aureus-infected wounds.

RESULTS

ROX/Oxi-αCD NPs and rhEGF/ROX/Oxi-αCD NPs had a spherical structure and their particle sizes were 164 ± 5 nm and 190 ± 8 nm, respectively. The in vitro antibacterial experiments showed that ROX/Oxi-αCD NPs had a lower minimum inhibitory concentration than ROX. The in vivo animal experiments demonstrated that rhEGF/ROX/Oxi-αCD NPs could significantly accelerate the healing of S. aureus-infected wounds as compared to the free ROX drug and ROX/Oxi-αCD NPs (P < 0.05).

CONCLUSION

ROX and rhEGF co-loaded NPs can effectively eliminate bacteria in wounds and accelerate wound healing. Our present work could provide a new strategy to combat bacteria-infected wounds.

Analyzing secretory proteins in human dermal fibroblast-conditioned medium for angiogenesis: A bioinformatic approach

BACKGROUND

The conditioned medium from human dermal fibroblasts (dermal fibroblast-conditioned medium; DFCM) contains a diverse array of secretory proteins, including growth factors and wound repair-promoting proteins. Angiogenesis, a crucial process that facilitates the infiltration of inflammatory cells during wound repair, is induced by a hypoxic environment and inflammatory cytokines.

METHODS

In this study, we conducted a comprehensive bioinformatic analysis of 337 proteins identified through proteomics analysis of DFCM. We specifically focused on 64 DFCM proteins with potential involvement in angiogenesis. These proteins were further classified based on their characteristics, and we conducted a detailed analysis of their protein-protein interactions.

RESULTS

Gene Ontology protein classification categorized these 64 DFCM proteins into various classes, including metabolite interconversion enzymes (N = 11), protein modifying enzymes (N = 10), protein-binding activity modulators (N = 9), cell adhesion molecules (N = 6), extracellular matrix proteins (N = 6), transfer/carrier proteins (N = 3), calcium-binding proteins (N = 2), chaperones (N = 2), cytoskeletal proteins (N = 2), RNA metabolism proteins (N = 1), intercellular signal molecules (N = 1), transporters (N = 1), scaffold/adaptor proteins (N = 1), and unclassified proteins (N = 9). Furthermore, our protein-protein interaction network analysis of DFCM proteins revealed two distinct networks: one with medium confidence level interaction scores, consisting of 60 proteins with significant connections, and another at a high confidence level, comprising 52 proteins with significant interactions.

CONCLUSIONS

Our bioinformatic analysis highlights the presence of a multitude of secretory proteins in DFCM that form significant protein-protein interaction networks crucial for regulating angiogenesis. These findings underscore the critical roles played by DFCM proteins in various stages of angiogenesis during the wound repair process.

Phytochemistry and biological activity of Erigeron annuus (L.) Pers

Erigeron annuus L. is a flowering herb of North America, Europe, Asia and Russia. This plant is used as folk medicine in China for the cure of indigestion, enteritis, epidemic hepatitis, haematuria and diabetes. Phytochemical studies showed the presence of 170 bioactive compounds like coumarins, flavonoids, terpenoids, polyacetylenic compounds; γ-pyrone derivatives, sterols and various caffeoylquinic acids derived from the essential oil and organic extracts from its various parts such as aerial parts, roots, leaves, stems and flowers. The pharmacological studies demonstrated various extracts and the compounds of E. annuus to exhibit anti-fungal, anti-atherosclerosis, anti-inflammatory, antidiabetic, phytotoxic, cytoprotective, antiobesity and antioxidant activities. This article covers a critical compendious on geographical distribution, botanical description, phytochemistry, ethnomedicinal uses and pharmacological activities of E. annuus. However, further in-depth studies are needed to determine the medical uses of E. annuus and its chemical constituents, pharmacological activities and clinical applications.

Effects of TP63 mutations on keratinocyte adhesion and migration

The goal of this study was to investigate the molecular mechanisms responsible for the formation of skin erosions in patients affected by Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC). This ectodermal dysplasia is caused by mutations in the TP63 gene, which encodes several transcription factors that control epidermal development and homeostasis. We generated induced pluripotent stem cells (iPSC) from AEC patients and corrected the TP63 mutations using genome editing tools. Three pairs of the resulting conisogenic iPSC lines were differentiated into keratinocytes (iPSC-K). We identified a significant downregulation of key components of hemidesmosomes and focal adhesions in AEC iPSC-K compared to their gene-corrected counterparts. Further, we demonstrated reduced AEC iPSC-K migration, suggesting the possibility that a process critical for cutaneous wound healing might be impaired in AEC patients. Next, we generated chimeric mice expressing a TP63-AEC transgene and confirmed a downregulation of these genes in transgene-expressing cells in vivo. Finally, we also observed these abnormalities in AEC patient skin. Our findings suggest that integrin defects in AEC patients might weaken the adhesion of keratinocytes to the basement membrane. We propose that reduced expression of extracellular matrix adhesion receptors, potentially in conjunction with previously identified desmosomal protein defects, contribute to skin erosions in AEC.

Effects of TP63 Mutations on Keratinocyte Adhesion and Migration

The goal of this study was to investigate the molecular mechanisms responsible for the formation of skin erosions in patients affected by Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC). This ectodermal dysplasia is caused by mutations in the TP63 gene, which encodes several transcription factors that control epidermal development and homeostasis. We generated induced pluripotent stem cells (iPSC) from AEC patients and corrected the TP63 mutations using genome editing tools. Three pairs of the resulting conisogenic iPSC lines were differentiated into keratinocytes (iPSC-K). We identified a significant downregulation of key components of hemidesmosomes and focal adhesions in AEC iPSC-K compared to their gene-corrected counterparts. Further, we demonstrated reduced iPSC-K migration, suggesting the possibility that a process critical for cutaneous wound healing might be impaired in AEC patients. Next, we generated chimeric mice expressing a TP63-AEC transgene and confirmed a downregulation of these genes in transgene-expressing cells in vivo. Finally, we also observed these abnormalities in AEC patient skin. Our findings suggest that integrin defects in AEC patients might weaken the adhesion of keratinocytes to the basement membrane. We propose that reduced expression of extracellular matrix adhesion receptors, potentially in conjunction with previously identified desmosomal protein defects, contribute to skin erosions in AEC.

Recent advances in decellularized biomaterials for wound healing

The skin is one of the most essential organs in the human body, interacting with the external environment and shielding the body from diseases and excessive water loss. Thus, the loss of the integrity of large portions of the skin due to injury and illness may lead to significant disabilities and even death. Decellularized biomaterials derived from the extracellular matrix of tissues and organs are natural biomaterials with large quantities of bioactive macromolecules and peptides, which possess excellent physical structures and sophisticated biomolecules, and thus, promote wound healing and skin regeneration. Here, we highlighted the applications of decellularized materials in wound repair. First, the wound-healing process was reviewed. Second, we elucidated the mechanisms of several extracellular matrix constitutes in facilitating wound healing. Third, the major categories of decellularized materials in the treatment of cutaneous wounds in numerous preclinical models and over decades of clinical practice were elaborated. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues for research on decellularized biomaterials-based wound treatment.

Adipose-Derived Stem Cell Extracellular Vesicles Improve Wound Closure and Angiogenesis in Diabetic Mice

BACKGROUND

Currently, there is a lack in therapy that promotes the reepithelialization of diabetic wounds as an alternative to skin grafting. Here, the authors hypothesized that extracellular vesicles from adipose-derived stem cells (ADSC-EVs) could accelerate wound closure through rescuing the function of keratinocytes in diabetic mice.

METHODS

The effect of ADSC-EVs on the biological function of human keratinocyte cells was assayed in vitro. In vivo, 81 male severe combined immune deficiency mice aged 8 weeks were divided randomly into the extracellular vesicle-treated diabetes group (n = 27), the phosphate-buffered saline-treated diabetes group (n = 27), and the phosphate-buffered saline-treated normal group (n = 27). A round, 8-mm-diameter, full-skin defect was performed on the back skin of each mouse. The wound closure kinetics, average healing time, reepithelialization rate, and neovascularization were evaluated by histological staining.

RESULTS

In vitro, ADSC-EVs improved proliferation, migration, and proangiogenic potential, and inhibited the apoptosis of human keratinocyte cells by suppressing Fasl expression with the optimal dose of 40 μg/mL. In vivo, postoperative dripping of ADSC-EVs at the dose of 40 μg/mL accelerated diabetic wound healing, with a 15.8% increase in closure rate and a 3.3-day decrease in average healing time. ADSC-EVs improved reepithelialization (18.2%) with enhanced epithelial proliferation and filaggrin expression, and suppressed epithelial apoptosis and Fasl expression. A 2.7-fold increase in the number of CD31-positive cells was also observed.

CONCLUSION

ADSC-EVs improve diabetic wound closure and angiogenesis by enhancing keratinocyte-mediated reepithelialization and vascularization.

CLINICAL RELEVANCE STATEMENT

ADSC-EVs could be developed as a regenerative medicine for diabetic wound care.

Proteomic Identification and Quantification of Secretory Proteins in Human Dermal Fibroblast-Conditioned Medium for Wound Repair and Hair Regeneration

Background

Human dermal fibroblasts secrete numerous growth factors and proteins that have been suggested to promote wound repair and hair regeneration.

Methods

Human dermal fibroblast-conditioned medium (DFCM) was prepared, and proteomic analysis was performed. Secretory proteins in DFCM were identified using 1-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis, in-gel trypsin protein digestion, and quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS). Identified proteins were analyzed using bioinformatic methods for the classification and evaluation of protein-protein interactions.

Results

Using LC-MS/MS, 337 proteins were identified in DFCM. Among them, 160 proteins were associated with wound repair, and 57 proteins were associated with hair regeneration. Protein-protein interaction network analysis of 160 DFCM proteins for wound repair at the highest confidence score (0.9) revealed that 110 proteins were grouped into seven distinctive interaction networks. Additionally, protein-protein interaction network analysis of 57 proteins for hair regeneration at the highest confidence score revealed that 29 proteins were grouped into five distinctive interaction networks. The identified DFCM proteins were associated with several pathways for wound repair and hair regeneration, including epidermal growth factor receptor, fibroblast growth factor, integrin, Wnt, cadherin, and transforming growth factor-β signaling pathways.

Conclusion

DFCM contains numerous secretory proteins that comprise groups of protein-protein interaction networks that regulate wound repair and hair regeneration.

Poly(l-lactic acid) Scaffold Releasing an α4β1 Integrin Agonist Promotes Nonfibrotic Skin Wound Healing in Diabetic Mice

Skin wound healing is a highly complex process that continues to represent a major medical problem, due to chronic nonhealing wounds in several classes of patients and to possible fibrotic complications, which compromise the function of the dermis. Integrins are transmembrane receptors that play key roles in this process and that offer a recognized druggable target. Our group recently synthesized GM18, a specific agonist for α4β1, an integrin that plays a role in skin immunity and in the migration of neutrophils, also regulating the differentiated state of fibroblasts. GM18 can be combined with poly(l-lactic acid) (PLLA) nanofibers to provide a controlled release of this agonist, resulting in a medication particularly suitable for skin wounds. In this study, we first optimized a GM18-PLLA nanofiber combination with a 7-day sustained release for use as skin wound medication. When tested in an experimental pressure ulcer in diabetic mice, a model for chronic nonhealing wounds, both soluble and GM18-PLLA formulations accelerated wound healing, as well as regulated extracellular matrix synthesis toward a nonfibrotic molecular signature. In vitro experiments using the adhesion test showed fibroblasts to be a principal GM18 cellular target, which we then used as an in vitro model to explore possible mechanisms of GM18 action. Our results suggest that the observed antifibrotic behavior of GM18 may exert a dual action on fibroblasts at the α4β1 binding site and that GM18 may prevent profibrotic EDA-fibronectin-α4β1 binding and activate outside-in signaling of the ERK1/2 pathways, a critical component of the wound healing process.

A transient photoactivation of epidermal stem cells by femtosecond laser promotes skin wound healing

Wound healing is a long-term complex process, in which epidermal stem cells (EPSCs) in epidermis of skin have been found to play an essential role in it. We develop a noninvasive method to activate EPSCs in skin in vivo to promote wound healing, based on a microscopic system to enable a sequential frame-by-frame scanning of a femtosecond laser at 800 nm to the predefined skin region for a single time for 16 seconds. The laser is tightly focused on a submicron spot and localized in the epidermis, and scans point by point to activate EPSCs there. The density and stemness of EPSCs are significantly enhanced for at least 60 hours after the single-time transient photoactivation. We demonstrate this method works in a skin wound mouse model. Our results provide an optical method for in vivo EPSC activation and hold good potential in wound healing.

Integrin α3 negative podocytes: A gene expression study

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New cell model to investigate the impact of loss of integrin α3 in podocytes.

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In this novel model, genes of the extracellular matrix and adhesome are mostly downregulated.

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Loss of integrin α3 results in changes of cell adhesion and spreading.

Integrin α3β1 is a cell adhesion receptor widely expressed in epithelial cells. Pathogenic variants in the gene encoding the integrin α3 subunit ITGA3 lead to a syndrome including interstitial lung disease, nephrotic syndrome, and epidermolysis bullosa (ILNEB). Renal involvement mainly consists of glomerular disease caused by loss of adhesion between podocytes and the glomerular basement membrane.

The aim of this study was to characterize the impact of loss of integrin α3 on human podocytes.

ITGA3 was stably knocked-out in the human podocyte cell line AB8/13, designated as Podo^A3−, and in human proximal tubule epithelial cell line HK2 using the targeted genome editing technique CRISPR/Cas9. Cell clones were characterized by Sanger sequencing, quantitative PCR, Western Blot and immunofluorescence staining. RNASeq of integrin α3 negative cells and controls was performed to identify differential gene expression patterns.

Differentiated Podo^A3− did not substantially change morphology and adhesion under standard culture conditions, but displayed significantly reduced spreading and adhesion when seed on laminin 511 in serum free medium. Gene expression studies demonstrated a distinct dysregulation of the adhesion network with downregulation of most integrin α3 interaction partners. In agreement with this, biological processes such as “extracellular matrix organization” and “cell differentiation” as well as KEGG pathways such as “ECM-receptor interaction”, “focal adhesion” and the “PI3K-Akt signaling pathway” were significantly downregulated in human podocytes lacking the integrin α3 subunit.

The proliferative and multipotent epidermal progenitor cells for human skin reconstruction in vitro and in vivo

OBJECTIVES

The skin exhibits tremendous regenerative potential, as different types of progenitor and stem cells regulate skin homeostasis and damage. However, in vitro primary keratinocytes present with several drawbacks, such as high donor variability, short lifespan, and limited donor tissue availability. Therefore, more stable primary keratinocytes are needed to generate multiple uniform in vitro and in vivo skin models.

RESULTS

We identified epidermal progenitor cells from primary keratinocytes using Integrin beta 1 (ITGB1) an epidermal stem cell marker markedly decreased after senescence in vitro. Epidermal progenitor cells exhibited unlimited proliferation and the potential for multipotent differentiation capacity. Moreover, they could completely differentiate to form an organotypic skin model including conversed mesenchymal cells in the dermis and could mimic the morphologic and biochemical processes of human epidermis. We also discovered that proliferation and the multipotent differentiation capacity of these cells relied on ITGB1 expression. Eventually, we examined the in vitro and in vivo wound healing capacity of these epidermal progenitor cells.

CONCLUSIONS

Overall, the findings suggest that these stable and reproducible cells can differentiate into multiple lineages, including human skin models. They are a potentially powerful tool for studying skin regeneration, skin diseases, and are an alternative for in vivo experiments.

Milk fat-globule epidermal growth factor 8: A potential Regulator of Cutaneous Wound Healing

Destroying the integrity of the skin may causes disability and even death from injury or illness. Wound healing is a core mechanism to maintain skin barrier function. Milk fat-globule epidermal growth factor 8 (MFG-E8) is a key factor in wound healing and is involved in regulating blood coagulation, mediating macrophage uptake of apoptotic cells, shifting macrophages from an inflammatory to an anti-inflammatory phenotype, promoting angiogenesis, enhancing vascular endothelial growth factor (VEGF) signaling, and assisting wound tissue perfusion. However, these abilities are dysregulated in pathological conditions, such as glucose disorders and ischemic injury. Restricted application of exogenous MFG-E8 can restore function and play a beneficial role in cutaneous wound healing.

Mesenchymal stromal cells promote the proliferation of basal stem cells and efficient epithelization in organotypic models of wound healing

Adipose derived mesenchymal stromal cells (ADSCs) represent a fascinating tool in the scenario of wound healing and regenerative medicine. Recent data already demonstrated that ADSCs could exert a stimulatory action on epithelial cells through secretion of soluble factors. The aim of the present study was to assess how ADSCs guide wound re‐epithelization in vitro in the presence of keratinocytes. We used an organotypic model of wound healing and we seeded keratinocytes on a ADSC‐induced dermal matrix. Conventional hematoxylin–eosin stain and immunohistochemistry staining for Ki67, p63 and pan‐keratins were performed at different timepoints. Histological sections of organotypic cultures showed complete coverage of the ADSC‐induced matrix by keratinocytes. Proliferation of basal stem cells was found to be the main mechanism responsible for epithelization of the dermis. In conclusion, ADSC do not only stimulate dermal regeneration through collagen deposition but also promote epithelization.

Oncostatin M Improves Cutaneous Wound Re-Epithelialization and Is Deficient under Diabetic Conditions

Impaired re-epithelialization characterized by hyperkeratotic nonmigratory wound epithelium is a hallmark of nonhealing diabetic wounds. In chronic wounds, the copious release of oncostatin M (OSM) from wound macrophages is evident. OSM is a potent keratinocyte (KC) activator. This work sought to understand the signal transduction pathway responsible for wound re-epithelialization, the primary mechanism underlying wound closure. Daily topical treatment of full-thickness excisional wounds of C57BL/6 mice with recombinant murine OSM improved wound re-epithelialization and accelerated wound closure by bolstering KC proliferation and migration. OSM activated the Jak-signal transducer and activator of transcription pathway as manifested by signal transducer and activator of transcription 3 phosphorylation. Such signal transduction in the human KC induced TP63, the master regulator of KC function. Elevated TP63 induced ITGB1, a known effector of KC migration. In diabetic wounds, OSM was more abundant than the level in nondiabetic wounds. However, in diabetic wounds, OSM activity was compromised by glycation. Aminoguanidine, a deglycation agent, rescued the compromised KC migration caused by glycated OSM. Finally, topical application of recombinant OSM improved KC migration and accelerated wound closure in db/db mice. This work recognizes that despite its abundance at the wound site, OSM is inactivated by glycation, and topical delivery of exogenous OSM is likely to be productive in accelerating diabetic wound closure.

Thy-1 (CD90), Integrins and Syndecan 4 are Key Regulators of Skin Wound Healing

Acute skin wound healing is a multistage process consisting of a plethora of tightly regulated signaling events in specialized cells. The Thy-1 (CD90) glycoprotein interacts with integrins and the heparan sulfate proteoglycan syndecan 4, generating a trimolecular complex that triggers bi-directional signaling to regulate diverse aspects of the wound healing process. These proteins can act either as ligands or receptors, and they are critical for the successful progression of wound healing. The expression of Thy-1, integrins, and syndecan 4 is controlled during the healing process, and the lack of expression of any of these proteins results in delayed wound healing. Here, we review and discuss the roles and regulatory events along the stages of wound healing that support the relevance of Thy-1, integrins, and syndecan 4 as crucial regulators of skin wound healing.

Human amniotic epithelial cell transplantation improves scar remodeling in a rabbit model of acute vocal fold injury: a pilot study

Objective

To gain insight into the molecular mechanisms underlying the early stages of vocal fold extracellular matrix (ECM) remodeling after a mid-membranous injury resulting from the use of human amniotic epithelial cells (hAEC), as a novel regenerative medicine cell-based therapy.

Methods

Vocal folds of six female, New Zealand White rabbits were bilaterally injured. Three rabbits had immediate bilateral direct injection of 1 × 10⁶ hAEC in 100 µl of saline solution (hAEC) and three with 100 µl of saline solution (controls, CTR). Rabbits were euthanized 6 weeks after injury. Proteomic analyses (in-gel trypsin protein digestion, LC–MS/MS, protein identification using Proteome Discoverer and the Uniprot Oryctolagus cuniculus (Rabbit) proteome) and histological analyses were performed.

Results

hAEC treatment significantly increased the expression of ECM proteins, elastin microfibril interface-located protein 1 (EMILIN-1) and myocilin that are primarily involved in elastogenesis of blood vessels and granulation tissue. A reactome pathway analysis showed increased activity of the anchoring fibril formation by collagen I and laminin, providing mechanical stability and activation of cell signaling pathways regulating cell function. hAEC increased the abundance of keratin 1 indicating accelerated induction of the differentiation programming of the basal epithelial cells and, thereby, improved barrier function. Lastly, upregulation of Rab GDP dissociation inhibitor indicates that hAEC activate the vesicle endocytic and exocytic pathways, supporting the exosome-mediated activation of cell–matrix and cell-to-cell interactions.

Conclusions

This pilot study suggests that injection of hAEC into an injured rabbit vocal fold favorably alters ECM composition creating a microenvironment that accelerates differentiation of regenerated epithelium and promotes stabilization of new blood vessels indicative of accelerated and improved repair.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02701-w.

Single-Cell and Bulk Transcriptome Data Integration Reveals Dysfunctional Cell Types and Aberrantly Expressed Genes in Hypertrophic Scar

Hypertrophic scar (HS) is a common skin disorder characterized by excessive extracellular matrix (ECM) deposition. However, it is still unclear how the cellular composition, cell-cell communications, and crucial transcriptionally regulatory network were changed in HS. In the present study, we found that FB-1, which was identified a major type of fibroblast and had the characteristics of myofibroblast, was significantly expanded in HS by integrative analysis of the single-cell and bulk RNA sequencing (RNA-seq) data. Moreover, the proportion of KC-2, which might be a differentiated type of keratinocyte (KC), was reduced in HS. To decipher the intercellular signaling, we conducted the cell-cell communication analysis between the cell types, and found the autocrine signaling of HB-1 through COL1A1/2-CD44 and CD99-CD99 and the intercellular contacts between FB-1/FB-5 and KC-2 through COL1A1/COL1A2/COL6A1/COL6A2-SDC4. Almost all the ligands and receptors involved in the autocrine signaling of HB-1 were upregulated in HS by both scRNA-seq and bulk RNA-seq data. In contrast, the receptor of KC-2, SDC4, which could bind to multiple ligands, was downregulated in HS, suggesting that the reduced proportion of KC-2 and apoptotic phenotype of KC-2 might be associated with the downregulation of SDC4. Furthermore, we also investigated the transcriptionally regulatory network involved in HS formation. The integrative analysis of the scRNA-seq and bulk RNA-seq data identified CREB3L1 and TWIST2 as the critical TFs involved in the myofibroblast of HS. In summary, the integrative analysis of the single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data greatly improved our understanding of the biological characteristics during the HS formation.

α4/α9 Integrins Coordinate Epithelial Cell Migration Through Local Suppression of MAP Kinase Signaling Pathways

Adhesion of basal keratinocytes to the underlying extracellular matrix (ECM) plays a key role in the control of skin homeostasis and response to injury. Integrin receptors indirectly link the ECM to the cell cytoskeleton through large protein complexes called focal adhesions (FA). FA also function as intracellular biochemical signaling platforms to enable cells to respond to changing extracellular cues. The α4β1 and α9β1 integrins are both expressed in basal keratinocytes, share some common ECM ligands, and have been shown to promote wound healing in vitro and in vivo. However, their roles in maintaining epidermal homeostasis and relative contributions to pathological processes in the skin remain unclear. We found that α4β1 and α9β1 occupied distinct regions in monolayers of a basal keratinocyte cell line (NEB-1). During collective cell migration (CCM), α4 and α9 integrins co-localized along the leading edge. Pharmacological inhibition of α4β1 and α9β1 integrins increased keratinocyte proliferation and induced a dramatic change in cytoskeletal remodeling and FA rearrangement, detrimentally affecting CCM. Further analysis revealed that α4β1/α9β1 integrins suppress extracellular signal-regulated kinase (ERK1/2) activity to control migration through the regulation of downstream kinases including Mitogen and Stress Activated Kinase 1 (MSK1). This work demonstrates the roles of α4β1 and α9β1 in regulating migration in response to damage cues.

Wound healing in animals: a review of physiology and clinical evaluation

Wound healing is a complicated process consisting of overlapping phases directed and regulated by many mediators of healing produced locally at the wound. The end goal of wound healing is the production of tissue at the site of injury which has a similar structure and provides protection to the body. Any alterations in the normal healing process can lead to delayed healing or additional tissue damage. Factors that contribute to aberrant wound healing can be species-specific and include both intrinsic (systemic) factors and extrinsic (environmental) factors. Management of wounds and recognition of alterations can be optimised by adoption of a structured framework for wound assessment, such as the TIME principle (acronym referring to the following categories: tissue, inflammation or infection, moisture, and edge of wound or epithelial advancement). This review article provides an overview of the phases of wound healing, variation of healing among different species, factors reported to delay healing, and an introduction to the TIME principle as a structured approach to clinical evaluation of wounds.

Mass Spectrometry Imaging of Fibroblasts: Promise and Challenge

INTRODUCTION

Fibroblasts maintain tissue and organ homeostasis through output of extracellular matrix that affects nearby cell signaling within the stroma. Altered fibroblast signaling contributes to many disease states and extracellular matrix secreted by fibroblasts has been used to stratify patient by outcome, recurrence, and therapeutic resistance. Recent advances in imaging mass spectrometry allow access to single cell fibroblasts and their ECM niche within clinically relevant tissue samples.

AREAS COVERED

We review biological and technical challenges as well as new solutions to proteomic access of fibroblast expression within the complex tissue microenvironment. Review topics cover conventional proteomic methods for single fibroblast analysis and current approaches to accessing single fibroblast proteomes by imaging mass spectrometry approaches. Strategies to target and evaluate the single cell stroma proteome on the basis of cell signaling are presented.

EXPERT OPINION

The promise of defining proteomic signatures from fibroblasts and their extracellular matrix niches is the discovery of new disease markers and the ability to refine therapeutic treatments. Several imaging mass spectrometry approaches exist to define the fibroblast in the setting of pathological changes from clinically acquired samples. Continued technology advances are needed to access and understand the stromal proteome and apply testing to the clinic.

Melanocyte Precursors in the Hair Follicle Bulge of Repigmented Vitiligo Skin Are Controlled by RHO-GTPase, KCTD10, and CTNNB1 Signaling

In repigmentation of human vitiligo, the melanocyte (MC) precursors in the hair follicle bulge proliferate, migrate, and differentiate to repopulate the depigmented epidermis. Here, we present a comprehensive characterization of pathways and signals in the bulge that control the repigmentation process. Using biopsies from patients with vitiligo, we have selectively harvested, by laser capture microdissection, MC and keratinocyte precursors from the hair follicle bulge of untreated vitiligo skin and vitiligo skin treated with narrow-band UVB. The captured material was subjected to whole transcriptome RNA-sequencing. With this strategy, we found that repigmentation in the bulge MC precursors is driven by KCTD10, a signal with unknown roles in the skin, and CTNNB1 (encoding β-catenin) and RHO guanosine triphosphatase [RHO GTPase, RHO], two signaling pathways previously shown to be involved in pigmentation biology. Knockdown studies in cultured human MCs of RHOJ, the upmost differentially expressed RHO family component, corroborated with our findings in patients with vitiligo, identified RHOJ involvement in UV response and melanization, and confirmed previously identified roles in melanocytic cell migration and apoptosis. A better understanding of mechanisms that govern repigmentation in MC precursors will enable the discovery of molecules that induce robust repigmentation phenotypes in vitiligo.

Emerging Roles of Matricellular Proteins in Systemic Sclerosis

Systemic sclerosis is a rare chronic heterogenous disease that involves inflammation and vasculopathy, and converges in end-stage development of multisystem tissue fibrosis. The loss of tight spatial distribution and temporal expression of proteins in the extracellular matrix (ECM) leads to progressive organ stiffening, which is a hallmark of fibrotic disease. A group of nonstructural matrix proteins, known as matricellular proteins (MCPs) are implicated in dysregulated processes that drive fibrosis such as ECM remodeling and various cellular behaviors. Accordingly, MCPs have been described in the context of fibrosis in sclerosis (SSc) as predictive disease biomarkers and regulators of ECM synthesis, with promising therapeutic potential. In this present review, an informative summary of major MCPs is presented highlighting their clear correlations to SSc- fibrosis.

Migration- and Proliferation-Promoting Activities in Human Keratinocytes of Zea mays Flower Absolute and Its Chemical Composition

Zea mays L. (ZM) has cytotoxic and anti-inflammatory activities, but its biological activities such as skin regeneration and wound healing in human skin have not been reported. In the present study, we tested the effects of ZM flower (ZMF) absolute on proliferation and migration of human keratinocytes (HaCaTs) and identified its components by using gas chromatography/mass spectrometry (GC/MS) analysis. GC/MS analysis revealed that the ZMF absolute contained 13 constituents, and it increased HaCaT proliferation and migration. The ZMF absolute enhanced the phosphorylation levels of serine/threonine-specific protein kinase (Akt), p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase1/2 in HaCaTs. In addition, the absolute induced an increase in sprout outgrowth of HaCaTs. The present study reports for the first time that ZMF absolute may promote skin wound healing and/or skin regeneration by stimulating proliferative and migratory activities in dermal keratinocytes through the Akt/MAPK pathway. Therefore, ZMF absolute may be a promising natural material for the use in skin regeneration and/or wound healing applications.

Coating biopolymer nanofibers with carbon nanotubes accelerates tissue healing and bone regeneration through orchestrated cell- and tissue-regulatory responses

Tailoring the surface of biomaterial scaffolds has been a key strategy to modulate the cellular interactions that are helpful for tissue healing process. In particular, nanotopological surfaces have been demonstrated to regulate diverse behaviors of stem cells, such as initial adhesion, spreading and lineage specification. Here, we tailor the surface of biopolymer nanofibers with carbon nanotubes (CNTs) to create a unique bi-modal nanoscale topography (500 nm nanofiber with 25 nm nanotubes) and report the performance in modulating diverse in vivo responses including inflammation, angiogenesis, and bone regeneration. When administered to a rat subcutaneous site, the CNT-coated nanofiber exhibited significantly reduced inflammatory signs (down-regulated pro-inflammatory cytokines and macrophages gathering). Moreover, the CNT-coated nanofibers showed substantially promoted angiogenic responses, with enhanced neoblood vessel formation and angiogenic marker expression. Such stimulated tissue healing events by the CNT interfacing were evidenced in a calvarium bone defect model. The in vivo bone regeneration of the CNT- coated nanofibers was significantly accelerated, with higher bone mineral density and up-regulated osteogenic signs (OPN, OCN, BMP2) of in vivo bone forming cells. The in vitro studies using MSCs could demonstrate accelerated adhesion and osteogenic differentiation and mineralization, supporting the osteo-promoting mechanism behind the in vivo bone forming event. These findings highlight that the CNTs interfacing of biopolymer nanofibers is highly effective in reducing inflammation, promoting angiogenesis, and driving adhesion and osteogenesis of MSCs, which eventually orchestrate to accelerate tissue healing and bone regeneration process. STATEMENT OF SIGNIFICANCE: Here we demonstrate that the interfacing of biopolymer nanofibers with carbon nanotubes (CNTs) could modulate multiple interactions of cells and tissues that are ultimately helpful for the tissue healing and bone regeneration process. The CNT-coated scaffolds significantly reduced the pro-inflammatory signals while stimulating the angiogenic marker expressions. Furthermore, the CNT-coated scaffolds increased the bone matrix production of bone forming cells in vivo as well as accelerated the adhesion and osteogenic differentiation of MSCs in vitro. These collective findings highlight that the CNTs coated on the biopolymer nanofibers allow the creation of a promising platform for nanoscale engineering of biomaterial surface that can favor tissue healing and bone regeneration process, through a series of orchestrated events in anti-inflammation, pro-angiogenesis, and stem cell stimulation.

Cell-specific expression of the transcriptional regulator RHAMM provides a timing mechanism that controls appropriate wound re-epithelialization

Prevention of aberrant cutaneous wound repair and appropriate regeneration of an intact and functional integument require the coordinated timing of fibroblast and keratinocyte migration. Here, we identified a mechanism whereby opposing cell-specific motogenic functions of a multifunctional intracellular and extracellular protein, the receptor for hyaluronan-mediated motility (RHAMM), coordinates fibroblast and keratinocyte migration speed and ensures appropriate timing of excisional wound closure. We found that, unlike in WT mice, in Rhamm-null mice, keratinocyte migration initiates prematurely in the excisional wounds, resulting in wounds that have re-surfaced before the formation of normal granulation tissue, leading to a defective epidermal architecture. We also noted aberrant keratinocyte and fibroblast migration in the Rhamm-null mice, indicating that RHAMM suppresses keratinocyte motility but increases fibroblast motility. This cell context-dependent effect resulted from cell-specific regulation of extracellular signal-regulated kinase 1/2 (ERK1/2) activation and expression of a RHAMM target gene encoding matrix metalloprotease 9 (MMP-9). In fibroblasts, RHAMM promoted ERK1/2 activation and MMP-9 expression, whereas in keratinocytes, RHAMM suppressed these activities. In keratinocytes, loss of RHAMM function or expression promoted epidermal growth factor receptor-regulated MMP-9 expression via ERK1/2, which resulted in cleavage of the ectodomain of the RHAMM partner protein CD44 and thereby increased keratinocyte motility. These results identify RHAMM as a key factor that integrates the timing of wound repair by controlling cell migration.

Kinin B1 Receptor Signaling in Skin Homeostasis and Wound Healing

Kinins are proinflammatory peptides that are formed in the skin by the enzymatic action of tissue kallikrein (KLK1) on kininogens. Tissue kallikrein is produced by eccrine sweat glands and also by cells of the stratum granulosum and other skin appendages. Kinin formation may be favored during inflammatory skin disorders when plasma constituents, including kininogens, extravasate from venules and capillaries, which have increased permeability in response to the plethora of inflammatory mediators generated in the course of acute inflammation. By activating either kinin B1 or B2 receptors, kinins modulate keratinocyte differentiation, which relays on activation of several signaling systems that follows receptor stimulation. Participation of the kinin B1 receptor in wound healing is still a matter of controversy though some studies indicate that B1 receptor stimulation regulates keratinocyte migration by controlling metalloproteases 2 and 9 production and by improving wound closure in a mouse model. Development of more stable kinin B1 receptor agonists may be beneficial to modulate wound healing, especially if we take into account that the B1 receptor is up-regulated by inflammation and by cytokines generated in the inflamed microenvironment.

Cartilage acidic protein 1 promotes increased cell viability, cell proliferation and energy metabolism in primary human dermal fibroblasts

Cartilage acidic protein 1 (CRTAC1) is an extracellular matrix protein of human chondrogenic tissue that is also present in other vertebrates, non-vertebrate eukaryotes and in some prokaryotes. The function of CRTAC1 remains unknown but the protein's structure indicates a role in cell-cell or cell-matrix interactions and calcium-binding. The aim of the present study was to evaluate the in vitro effects of hCRTAC1-A on normal human dermal fibroblasts (NHDF). A battery of in vitro assays (biochemical and PCR), immunofluorescence and a biosensor approach were used to characterize the protein's biological activities on NHDF cells in a scratch assay. Gene expression analysis revealed that hCRTAC1-A protein is associated with altered levels of expression for genes involved in the processes of cell proliferation (CXCL12 and NOS2), cell migration (AQP3 and TNC), and extracellular matrix-ECM regeneration and remodeling (FMOD, TIMP1, FN1) indicating a role for hCRTAC1-A in promoting these activities in a scratch assay. In parallel, the candidate processes identified by differential gene transcription were substantiated and extended using Electric cell-substrate impedance sensing (ECIS) technology, immunofluorescence and cell viability assays. Our findings indicate that hCRTAC1-A stimulated cell proliferation, migration and ECM production in primary human fibroblasts in vitro.

Differential expression of α6 and β1 integrins reveals epidermal heterogeneity at single-cell resolution

Skin epidermis is a constantly renewing epithelium that is composed of various cell types and provides an ideal model system for tissue regeneration and heterogeneity studies. Integrins are a family of transmembrane receptors that mediate cell adhesion in the epidermis, and integrin expression spatially reflects epidermal heterogeneity. It remains unclear whether differential expression of integrins can characterize cell types in skin epidermis. This study applied a fluorescence-activated cell sorting (FACS) strategy based on differential expression of α6 and β1 integrins, and used transcriptome analysis to explore epidermal heterogeneity. First, epidermal cells were acquired from C57BL/6 mice back skin. Nine bulk-cell populations were sorted with differential expressions of α6 and β1 integrins, and were successfully characterized as the main cell types in the epidermis through RNA-seq and transcriptome analysis. Then, tetOKrt14-H2BGFP mice were used to trace the cell proliferation rate during wound healing with GFP intensity. Epidermal cells were acquired from the re-epithelialized back skin wounds, and a total of 576 single cells were sorted, combining integrin expression and GFP tracing. FACS single-cell RNA-seq enabled high resolution in the classification of subtypes in both interfollicular epidermis and hair follicle, and both quiescent and intermediate cell states of the basal and infundibulum stem cell populations were distinguished. This study proposed a presorted method to investigate the relationship between integrin expression and epidermal heterogeneity. Multiple epidermal cell types and their expression profiles were identified, which provides data resources for dermatology research.

Deregulated Adhesion Program in Palatal Keratinocytes of Orofacial Cleft Patients

Orofacial clefts (OFCs) are the most frequent craniofacial birth defects. An orofacial cleft (OFC) occurs as a result of deviations in palatogenesis. Cell proliferation, differentiation, adhesion, migration and apoptosis are crucial in palatogenesis. We hypothesized that deregulation of these processes in oral keratinocytes contributes to OFC. We performed microarray expression analysis on palatal keratinocytes from OFC and non-OFC individuals. Principal component analysis showed a clear difference in gene expression with 24% and 17% for the first and second component, respectively. In OFC cells, 228 genes were differentially expressed (p < 0.001). Gene ontology analysis showed enrichment of genes involved in β1 integrin-mediated adhesion and migration, as well as in P-cadherin expression. A scratch assay demonstrated reduced migration of OFC keratinocytes (343.6 ± 29.62 μm) vs. non-OFC keratinocytes (503.4 ± 41.81 μm, p < 0.05). Our results indicate that adhesion and migration are deregulated in OFC keratinocytes, which might contribute to OFC pathogenesis.

Extracellular matrix deposition by adipose-derived stem cells and fibroblasts: a comparative study

Cell-based strategies are today widely studied as possible therapies for wound healing. In this setting, fibroblasts play a key role since they are the main dermal cellular component and are responsible for extracellular matrix secretion. Several works report on the possibility of using fibroblast-derived extracellular matrix scaffolds for wound healing in skin injuries. While fibroblast-based substitutes have already been intensively studied by other groups, we focused our attention on the possibility of creating an adipose-derived stem cell (ADSC)-induced dermal scaffold for wound healing. ADSCs are a particular subset of mesenchymal stem cells present in the stromal vascular fraction of the adipose tissue. The aim of our work was to compare the ability of ADSCs and fibroblast to produce in vitro a scaffolding material, both in terms of collagen and fibronectin production. ADSCs turned out to be capable of efficiently producing a collagen and fibronectin-containing dermal matrix upon stimulation with ascorbic acid. We observed fibronectin and collagen production by ADSCs to be even more abundant when compared to fibroblasts'. Our results support the use of ADSC-induced sheets instead of fibroblast-based dermal substitutes as wound-healing strategies in full-thickness skin injuries.

Peptide-Functionalized Hydrogels Modulate Integrin Expression and Stemness in Adult Human Epidermal Keratinocytes

The extracellular matrix (ECM) controls keratinocyte proliferation, migration, and differentiation through β-integrin signaling. Wound-healing research requires expanding cells in vitro while maintaining replicative capacity; however, early terminal differentiation under traditional culture conditions limits expansion. Here, a design of experiments approach identifies poly(ethylene glycol)-based hydrogel formulations with mechanical properties (elastic modulus, E = 20.9 ± 0.56 kPa) and bioactive peptide sequences that mimic the epidermal ECM. These hydrogels enable systematic investigation of the influence of cell-binding domains from fibronectin (RGDS), laminin (YIGSR), and collagen IV (HepIII) on keratinocyte stemness and β₁ integrin expression. Quantification of 14-day keratin protein expression shows four hydrogels improve stemness compared to standard techniques. Three hydrogels increase β₁ integrin expression, demonstrating a positive linear relationship between stemness and β₁ integrin expression. Multifactorial statistical analysis predicts an optimal peptide combination ([RGDS] = 0.67 mm, [YIGSR] = 0.13 mm, and [HepIII] = 0.02 mm) for maintaining stemness in vitro. Best-performing hydrogels exhibit no decrease in Ki-67-positive cells compared to standards (15% decrease, day 7 to 14; p < 0.05, Tukey Test). These data demonstrate that precisely designed hydrogel biomaterials direct integrin expression and promote proliferation, improving the regenerative capability of cultured keratinocytes for basic science and translational work.

Dynamic expression of α6 integrin indicates epidermal cell behaviors

Skin epidermis is a stratified epithelium that composed of interfollicular epidermis (IFE) and hair follicles (HFs). Integrins are cell-cell and cell-matrix adhesive ligands that play important roles in epidermal cell proliferation, migration and differentiation behaviors. Here, we analyzed the expression of both α6 and β1 integrins. In vitro epidermal cell culture, both α6 and β1 integrins displayed downregulation upon high Ca²⁺ induced differentiation. During wound healing (WH), α6 integrin showed dynamic expression, first greatly upregulated in unclosed wounds and then downregulated upon re-epithelialization. Further analysis of different wound regions confirmed α6 integrin significantly increased in migratory cells and migration was coupled with differentiation. However, expression level of β1 integrin did not show significant correlation with migration. We discovered that α6 integrin directly indicates epidermal cell differentiation and wound directed migration behaviors with its expression level.

Chemical Composition of Patrinia scabiosifolia Flower Absolute and Its Migratory and Proliferative Activities in Human Keratinocytes

Patrinia scabiosifolia (PS) has bioactivities such as antitumor and anti-inflammation effects. However, its effects on human skin physiological activities, such as skin regeneration and wound healing, remain unclear. In this study, we investigated the effects of absolute extracted from PS flower (PSF) on migration and proliferation of human dermal keratinocyte (HaCat). The yield of PSF absolute obtained by solvent extraction method was 0.105 % and its five constituents were found in GC/MS analysis. The PSF absolute induced the proliferation and migration of HaCats. The absolute increased the phosphorylation of serine/threonine-specific protein kinase (Akt) and extracellular signal-regulated kinase1/2 (Erk1/2) in HaCats. In addition, the absolute stimulated the outgrowth of collagen sprouting of HaCats. These results demonstrated, for the first time, that PSF absolute may have positive effects on skin regeneration and/or wound healing by inducing migration and proliferation of dermal keratinocytes via the Akt/Erk1/2 pathway. Therefore, PSF absolute may be a useful natural material for skin regeneration and/or wound healing.

In vitro Engineering of a Skin Substitute Based on Adipose-Derived Stem Cells

In the field of wound healing, stem cell-based strategies are gaining importance for their regenerative potential. Adipose-derived stem cells (ADSCs) are a particular subset of mesenchymal stem cells present in the stromal-vascular fraction of the adipose tissue, today considered very attractive for their relative abundance and accessibility in the human body. However, ADSCs are still not routinely used in normal clinical practice. Several studies have also reported ADSC transplantation in association with biomaterials in an attempt to enhance the local retention and growth rate of the cells. The aim of our study was to evaluate the ability of ADSCs to build a dermal scaffold to be potentially used as a dermal substitute in the field of wound healing, with optimal biocompatibility and mechanical properties. ADSCs were defined as CD90-, CD73-, and CD105-positive cells. ADSCs turned out to be capable of secreting all the main components of the extracellular matrix (ECM) upon stimulation, thus efficiently producing a collagen and fibronectin-containing dermal matrix. We also checked whether the ADSC-produced dermal scaffold could be seeded with keratinocytes. The scaffolding material directly produced by ADSCs has several advantages when compared to the commercially available ones: it is easily obtained from the patients and it is 100% biocompatible and supports cell-ECM interaction. Moreover, it represents a possible powerful therapeutic tool for patients with chronic ulcers since it appears to be potentially grafted with keratinocytes layers, thus bypassing the classical two-step grafting procedure.

Effect of Preparation Method on the Protein Profile of Equine Amnion Dressings

The protein content of amnion is thought to be the primary contributor to its efficacy as a biological dressing for wounds. Protein elution into antibiotic processing media has been reported, but the effect of antiseptic-based processing methods is unknown. Amniotic membranes were collected from eight healthy mares. Samples were collected after removal of gross debris. Tissues were subsequently divided and processed with either 0.05% chlorhexidine or 2% iodine/0.25% acetic acid. After protein extraction and trypsin digestion, the proteins were labeled with 8-plex iTRAQ tags, combined, and analyzed by high-resolution liquid chromatography-mass spectrometry. The MaxQuant-Perseus software suite was used to identify and quantify sample proteins, with functional annotation performed in PANTHER. There were 220 unique proteins identified, of which 144 were found in all individuals and across all conditions, several with a known role in wound healing. Contrary to expectations, processing did not significantly alter the protein content of the amnion tissue. Limitations include the small sample size and single time point. These results suggest that either processing method is acceptable for use in the preparation of equine amnion dressings. The role of expressed proteins in the biological activity of amnion dressings remains to be elucidated.

Integrin Regulation of CAF Differentiation and Function

Extensive remodeling of the extracellular matrix, together with paracrine communication between tumor cells and stromal cells, contribute to an “activated” tumor microenvironment that supports malignant growth and progression. These stromal cells include inflammatory cells, endothelial cells, and cancer-associated fibroblasts (CAFs). Integrins are expressed on all tumor and stromal cell types where they regulate both cell adhesion and bidirectional signal transduction across the cell membrane. In this capacity, integrins control pro-tumorigenic cell autonomous functions such as growth and survival, as well as paracrine crosstalk between tumor cells and stromal cells. The myofibroblast-like properties of cancer-associated fibroblasts (CAFs), such as robust contractility and extracellular matrix (ECM) deposition, allow them to generate both chemical and mechanical signals that support invasive tumor growth. In this review, we discuss the roles of integrins in regulating the ability of CAFs to generate and respond to extracellular cues in the tumor microenvironment. Since functions of specific integrins in CAFs are only beginning to emerge, we take advantage of a more extensive literature on how integrins regulate wound myofibroblast differentiation and function, as some of these integrin functions are likely to extrapolate to CAFs within the tumor microenvironment. In addition, we discuss the roles that integrins play in controlling paracrine signals that emanate from epithelial/tumor cells to stimulate fibroblasts/CAFs.

Laminin 332-Dependent YAP Dysregulation Depletes Epidermal Stem Cells in Junctional Epidermolysis Bullosa

Laminin 332-deficient junctional epidermolysis bullosa (JEB) is a severe genetic skin disease. JEB is marked by epidermal stem cell depletion, the origin of which is unknown. We show that dysregulation of the YAP and TAZ pathway underpins such stem cell depletion. Laminin 332-mediated YAP activity sustains human epidermal stem cells, detected as holoclones. Ablation of YAP selectively depletes holoclones, while enforced YAP blocks conversion of stem cells into progenitors and indefinitely extends the keratinocyte lifespan. YAP is dramatically decreased in JEB keratinocytes, which contain only phosphorylated, inactive YAP. In normal keratinocytes, laminin 332 and α6β4 ablation abolish YAP activity and recapitulate the JEB phenotype. In JEB keratinocytes, laminin 332-gene therapy rescues YAP activity and epidermal stem cells in vitro and in vivo. In JEB cells, enforced YAP recapitulates laminin 332-gene therapy, thus uncoupling adhesion from proliferation in epidermal stem cells. This work has important clinical implication for ex vivo gene therapy of JEB.

Keratinocyte Integrin α3β1 Promotes Secretion of IL-1α to Effect Paracrine Regulation of Fibroblast Gene Expression and Differentiation

After cutaneous injury, keratinocytes secrete paracrine factors that regulate wound cell functions; dysregulation of this signaling can lead to wound pathologies. Previously, we established that keratinocyte integrin α3β1 promotes wound angiogenesis through paracrine stimulation of endothelial cells. We hypothesize here that α3β1-dependent paracrine signaling from keratinocytes regulates the differentiation state of myofibroblasts. We report that epidermal α3-knockout mice exhibit more wound myofibroblasts and fewer cyclooxygenase 2 (Cox-2)-positive dermal cells than controls. We also found that conditioned medium from α3-expressing mouse keratinocytes (MKα3⁺), but not from α3-null MK cells (MKα3^-), induces expression of Cox-2 in fibroblasts in a time- and dose-dependent manner and that this induction is mediated by IL-1α. Compared with MKα3^- cells, MKα3⁺ cells secrete more IL-1α and less IL-1RA, a natural IL-1 receptor antagonist. Treatment with an IL-1α neutralizing antibody, recombinant IL-1RA, or IL-1 receptor-targeting small interfering RNA suppresses MKα3⁺ conditioned medium-dependent induction of Cox-2 expression in fibroblasts. Finally, active recombinant IL-1α is sufficient to induce Cox-2 in fibroblasts and to inhibit transforming growth factor-β-induced α-SMA expression. Our findings support a role for keratinocyte integrin α3β1 in controlling the secretion of IL-1α, a paracrine factor that regulates the wound myofibroblast phenotype.

Regulation of cell migration by α4 and α9 integrins

Integrins are heterodimeric transmembrane receptors that play an essential role in enabling cells to sense and bind to extracellular ligands. Activation and clustering of integrins leads to the formation of focal adhesions at the plasma membrane that subsequently initiate signalling pathways to control a broad range of functional endpoints including cell migration, proliferation and survival. The α4 and α9 integrins form a small sub-family of receptors that share some specific ligands and binding partners. Although relatively poorly studied compared with other integrin family members, emerging evidence suggests that despite restricted cell and tissue expression profiles, these integrins play a key role in the regulation of signalling pathways controlling cytoskeletal remodelling and migration in both adherent and non-adherent cell types. This review summarises the known shared and specific roles for α4 and α9 integrins and highlights the importance of these receptors in controlling cell migration within both homeostatic and disease settings.

Requirement for and polarized localization of integrin proteins during Drosophila wound closure

Wound reepithelialization is an evolutionarily conserved process in which skin cells migrate as sheets to heal the breach and is critical to prevent infection but impaired in chronic wounds. Integrin heterodimers mediate attachment between epithelia and underlying extracellular matrix and also act in large signaling complexes. The complexity of the mammalian wound environment and evident redundancy among integrins has impeded determination of their specific contributions to reepithelialization. Taking advantage of the genetic tools and smaller number of integrins in Drosophila, we undertook a systematic in vivo analysis of integrin requirements in the reepithelialization of skin wounds in the larva. We identify αPS2-βPS and αPS3-βPS as the crucial integrin dimers and talin as the only integrin adhesion component required for reepithelialization. The integrins rapidly accumulate in a JNK-dependent manner in a few rows of cells surrounding a wound. Intriguingly, the integrins localize to the distal margin in these cells, instead of the frontal or lamellipodial distribution expected for proteins providing traction and recruit nonmuscle myosin II to the same location. These findings indicate that signaling roles of integrins may be important for epithelial polarization around wounds and lay the groundwork for using Drosophila to better understand integrin contributions to reepithelialization.

Membrane-Associated Kaposi Sarcoma-Associated Herpesvirus Glycoprotein B Promotes Cell Adhesion and Inhibits Migration of Cells via Upregulating IL-1β and TNF-α

OBJECTIVES

Kaposi sarcoma-associated herpesvirus (KSHV) glycoprotein B (gB) is expressed on the viral envelope as well as on the cytoplasmic membrane of infected cells. In the current study, we aimed to decipher the impact of membrane-associated gB on adhesion and migration of cells via modulating the expression of cytokines.

METHODS

A combination of polymerase chain reaction array, cell adhesion assay, and wound-healing migration assay was conducted to study the influence of the gB-induced cytokines on cell adhesion and migration.

RESULTS

Membrane-associated gB was demonstrated to significantly upregulate the expression of IL-1β and TNF-α. Elevated levels of these cytokines were observed in conditioned medium (CM) collected from gB-expressing cells (gB-CM) compared to CM collected from untransfected cells or cells transfected with empty vector. KSHV gB-induced IL-1β and TNF-α play a role in the ability of gB-CM to mediate cell adhesion while inhibiting migration.

CONCLUSION

Our results provide novel evidence that demonstrates full-length gB expressed on cell membrane to mediate adhesion and inhibit migration of cells not only by autocrine mechanism mediated by RGD-based interactions [Hussein et al.: BMC Cancer 2016; 16: 148], but also by paracrine mechanism mediated by gB-induced IL-1β and TNF-α.

Scarless wound healing: Transitioning from fetal research to regenerative healing

Since the discovery of scarless fetal skin wound healing, research in the field has expanded significantly with the hopes of advancing the finding to adult human patients. There are several differences between fetal and adult skin that have been exploited to facilitate scarless healing in adults including growth factors, cytokines, and extracellular matrix substitutes. However, no one therapy, pathway, or cell subtype is sufficient to support scarless wound healing in adult skin. More recently, products that contain or mimic fetal and adult uninjured dermis were introduced to the wound healing market with promising clinical outcomes. Through our review of the major experimental targets of fetal wound healing, we hope to encourage research in areas that may have a significant clinical impact. Additionally, we will investigate therapies currently in clinical use and evaluate whether they represent a legitimate advance in regenerative medicine or a vulnerary agent. WIREs Dev Biol 2018, 7:e309. doi: 10.1002/wdev.309 This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Plant Development > Cell Growth and Differentiation Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells.

Feasibility of cell-based therapy combined with descemetorhexis for treating Fuchs endothelial corneal dystrophy in rabbit model

Corneal transparency is maintained by the corneal endothelium through its pump and barrier function. Severe corneal endothelial damage results in dysregulation of water flow and eventually causes corneal haziness and deterioration of visual function. In 2013, we initiated clinical research of cell-based therapy for treating corneal decompensation. In that study, we removed an 8-mm diameter section of damaged corneal endothelium without removing Descemet’s membrane (the basement membrane of the corneal endothelium) and then injected cultured human corneal endothelial cells (CECs) into the anterior chamber. However, Descemet’s membrane exhibits clinically abnormal structural features [i.e., multiple collagenous excrescences (guttae) and thickening] in patients with Fuchs endothelial corneal dystrophy (FECD) and the advanced cornea guttae adversely affects the quality of vision, even in patients without corneal edema. The turnover time of cornea guttae is also not certain. Therefore, we used a rabbit model to evaluate the feasibility of Descemet’s membrane removal in the optical zone only, by performing a small 4-mm diameter descemetorhexis prior to CEC injection. We showed that the corneal endothelium is regenerated both on the corneal stroma (the area of Descemet’s membrane removal) and on the intact peripheral Descemet’s membrane, based on the expression of function-related markers and the restoration of corneal transparency. Recovery of the corneal transparency and central corneal thickness was delayed in areas of Descemet’s membrane removal, but the cell density of the regenerated corneal endothelium and the thickness of the central corneal did not differ between the areas with and without residual Descemet’s membrane at 14 days after CEC injection. Here, we demonstrate that removal of a pathological Descemet’s membrane by a small descemetorhexis is a feasible procedure for use in combination with cell-based therapy. The current strategy might be beneficial for improving visual quality after CEC injection as a treatment for FECD.

The role of TGFβ in wound healing pathologies

Wound healing is one of the most complex processes in multicellular organisms, involving numerous intra- and intercellular signalling pathways in various cell types. It involves extensive communication between the cellular constituents of diverse skin compartments and its extracellular matrix. Miscommunication during healing may have two distinct damaging consequences: the development of a chronic wound or the formation of a hypertrophic scar/keloid. Chronic wounds are defined as barrier defects that have not proceeded through orderly and timely reparation to regain structural and functional integrity. Several growth factors are involved in wound healing, of which transforming growth factor beta (TGFβ) is of particular importance for all phases of this procedure. It exerts pleiotropic effects on wound healing by regulating cell proliferation, differentiation, extracellular matrix production, and modulating the immune response. In this review we are presenting the role of TGFβ in physiological and pathological wound healing. We show that the context-dependent nature of the TGFβ signaling pathways on wound healing is the biggest challenge in order to gain a therapeutically applicable comprehensive knowledge of their specific involvement in chronic wounds.

Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing

The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented with other features including non-toxicity, biocompatibility, and safety.