Effect of TGFβ1, TGFβ3 and keratinocyte conditioned media on functional characteristics of dermal fibroblasts derived from reparative (Balb/c) and regenerative (Foxn1 deficient; nude) mouse models

Hypoxia and Foxn1 alter the proteomic signature of dermal fibroblasts to redirect scarless wound healing to scar-forming skin wound healing in Foxn1-/- mice

BACKGROUND

Foxn1-/- deficient mice are a rare model of regenerative skin wound healing among mammals. In wounded skin, the transcription factor Foxn1 interacting with hypoxia-regulated factors affects re-epithelialization, epithelial-mesenchymal transition (EMT) and dermal white adipose tissue (dWAT) reestablishment and is thus a factor regulating scar-forming/reparative healing. Here, we hypothesized that transcriptional crosstalk between Foxn1 and Hif-1α controls the switch from scarless (regenerative) to scar-present (reparative) skin wound healing. To verify this hypothesis, we examined (i) the effect of hypoxia/normoxia and Foxn1 signalling on the proteomic signature of Foxn1-/- (regenerative) dermal fibroblasts (DFs) and then (ii) explored the effect of Hif-1α or Foxn1/Hif-1α introduced by a lentiviral (LV) delivery vector to injured skin of regenerative Foxn1-/- mice with particular attention to the remodelling phase of healing.

RESULTS

We showed that hypoxic conditions and Foxn1 stimulation modified the proteome of Foxn1-/- DFs. Hypoxic conditions upregulated DF protein profiles, particularly those related to extracellular matrix (ECM) composition: plasminogen activator inhibitor-1 (Pai-1), Sdc4, Plod2, Plod1, Lox, Loxl2, Itga2, Vldlr, Ftl1, Vegfa, Hmox1, Fth1, and F3. We found that Pai-1 was stimulated by hypoxic conditions in regenerative Foxn1-/- DFs but was released by DFs to the culture media exclusively upon hypoxia and Foxn1 stimulation. We also found higher levels of Pai-1 protein in DFs isolated from Foxn1+/+ mice (reparative/scar-forming) than in DFs isolated from Foxn1-/- (regenerative/scarless) mice and triggered by injury increase in Foxn1 and Pai-1 protein in the skin of mice with active Foxn1 (Foxn1+/+ mice). Then, we demonstrated that the introduction of Foxn1 and Hif-1α via lentiviral injection into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing by increasing the wounded skin area and decreasing hyaluronic acid deposition and the collagen type III to I ratio. We also identified a stimulatory effect of LV-Foxn1 + LV-Hif-1α injection in the wounded skin of Foxn1-/- mice on Pai-1 protein levels.

CONCLUSIONS

The present data highlight the effect of hypoxia and Foxn1 on the protein profile and functionality of regenerative Foxn1-/- DFs and demonstrate that the introduction of Foxn1 and Hif-1α into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing.

Novel Factors Regulating Proliferation, Migration, and Differentiation of Fibroblasts, Keratinocytes, and Vascular Smooth Muscle Cells during Wound Healing

Chronic diabetic foot ulcers (DFUs) are a significant complication of diabetes mellitus, often leading to amputation, increased morbidity, and a substantial financial burden. Even with the advancements in the treatment of DFU, the risk of amputation still exists, and this occurs due to the presence of gangrene and osteomyelitis. Nonhealing in a chronic DFU is due to decreased angiogenesis, granulation tissue formation, and extracellular matrix remodeling in the presence of persistent inflammation. During wound healing, the proliferation and migration of fibroblasts, smooth muscle cells, and keratinocytes play a critical role in extracellular matrix (ECM) remodeling, angiogenesis, and epithelialization. The molecular factors regulating the migration, proliferation, and differentiation of these cells are scarcely discussed in the literature. The literature review identifies the key factors influencing the proliferation, migration, and differentiation of fibroblasts, keratinocytes, and vascular smooth muscle cells (VSMCs), which are critical in wound healing. This is followed by a discussion on the various novel factors regulating the migration, proliferation, and differentiation of these cells but not in the context of wound healing; however, they may play a role. Using a network analysis, we examined the interactions between various factors, and the findings suggest that the novel factors identified may play a significant role in promoting angiogenesis, granulation tissue formation, and extracellular matrix remodeling during wound healing or DFU healing. However, these interactions warrant further investigation to establish their role alone or synergistically.

Comprehensive Biosafety Profile of Carbomer-Based Hydrogel Formulations Incorporating Phosphorus Derivatives

Determining the safety of a newly developed experimental product is a crucial condition for its medical use, especially for clinical trials. In this regard, four hydrogel-type formulations were manufactured, all of which were based on carbomer (Blank-CP940) and encapsulated with caffeine (CAF-CP940), phosphorus derivatives (phenyl phosphinic (CAF-S1-CP940) and 2-carboxyethyl phenyl phosphinic acids (CAF-S2-CP940)). The main aim of this research was to provide a comprehensive outline of the biosafety profile of the above-mentioned hydrogels. The complex in vitro screening (cell viability, cytotoxicity, morphological changes in response to exposure, and changes in nuclei morphology) on two types of healthy skin cell lines (HaCaT-human keratinocytes and JB6 Cl 41-5a-murine epidermal cells) exhibited a good biosafety profile when both cell lines were treated for 24 h with 150 μg/mL of each hydrogel. A comprehensive analysis of the hydrogel's impact on the genetic profile of HaCaT cells sustains the in vitro experiments. The biosafety profile was completed with the in vivo and in ovo assays. The outcome revealed that the developed hydrogels exerted good biocompatibility after topical application on BALB/c nude mice's skin. It also revealed a lack of toxicity after exposure to the hen's chicken embryo. Further investigations are needed, regarding the in vitro and in vivo therapeutic efficacy and safety for long-term use and potential clinical translatability.

Cobalt/Bioglass Nanoparticles Enhanced Dermal Regeneration in a 3-Layered Electrospun Scaffold

Purpose

Due to the multilayered structure of the skin tissue, the architecture of its engineered scaffolds needs to be improved. In the present study, 45s5 bioglass nanoparticles were selected to induce fibroblast proliferation and their protein secretion, although cobalt ions were added to increase their potency.

Methods

A 3-layer scaffold was designed as polyurethane (PU) - polycaprolactone (PCL)/ collagen/nanoparticles-PCL/collagen. The scaffolds examined by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), tensile, surface hydrophilicity and weight loss. Biological tests were performed to assess cell survival, adhesion and the pattern of gene expression.

Results

The mechanical assay showed the highest young modulus for the scaffold with the doped nanoparticles and the water contact angle of this scaffold after chemical crosslinking of collagen was reduced to 52.34±7.7°. In both assessments, the values were statistically compared to other groups. The weight loss of the corresponding scaffold was the highest value of 82.35±4.3 % due to the alkaline effect of metal ions and indicated significant relations in contrast to the scaffold with non-doped particles and bare one (P value<0.05). Moreover, better cell expansion, greater cell confluence and a lower degree of toxicity were confirmed. The up-regulation of TGF β1 and VEGF genes introduced this scaffold as a better model for the fibroblasts commitment to a new skin tissue among bare and nondoped scaffold (P value<0.05).

Conclusion

The 3-layered scaffold which is loaded with cobalt ions-bonded bioglass nanoparticles, is a better substrate for the culture of the fibroblasts.

Dermal white adipose tissue development and metabolism: The role of transcription factor Foxn1

Intradermal adipocytes form dermal white adipose tissue (dWAT), a unique fat depot localized in the lower layer of the dermis. However, recognition of molecular factors regulating dWAT development, homeostasis, and bioactivity is limited. Using Foxn1-/- and Foxn1+/+ mice, we demonstrated that epidermally expressed Foxn1 regulates dWAT development and defines the adipogenic capacity of dermal fibroblasts. In intact and post-wounded skin, Foxn1 contributes to the initial stimulation of dWAT adipogenesis and participates in the modulation of lipid metabolism processes. Furthermore, Foxn1 activity strengthens adipogenic processes through Bmp2 and Igf2 signaling and regulates lipid metabolism in differentiated dermal fibroblasts. The results reveal the contribution of Foxn1 to dWAT metabolism, thus identifying possible targets for modulation and regulation of dWAT in physiological and pathological processes in the skin.

Cordycepin-induced Keratinocyte Secretome Promotes Skin Cell Regeneration

BACKGROUND/AIM

Skin regeneration is the intrinsic ability to repair damaged skin tissues to regaining skin well-being. Processes of wound healing, a major part of skin regeneration, involve various types of cells, including keratinocytes and dermal fibroblasts, through their autocrine/paracrine signals. The releasable factors from keratinocytes were reported to influence dermal fibroblasts behavior during wound-healing processes. Here, we developed a strategy to modulate cytokine components and improve the secretome quality of HaCaT cells, a nontumorigenic immortalized keratinocyte cell line, via the treatment of cordycepin, and designated as cordycepin-induced HaCaT secretome (CHS).

MATERIALS AND METHODS

The bioactivities of CHS were investigated in vitro on human dermal fibroblasts (HDF). The effects of CHS on HDF proliferation, reactive oxygen species-scavenging, cell migration, extracellular matrix production and autophagy activation were investigated by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide cell viability assay, dichloro-dihydro-fluorescein diacetate, the wound-healing assay, reverse transcription polymerase chain reaction and immunofluorescent microscopy. Finally, Proteome Profiler™ Array was used to determine the composition of the secretome.

RESULTS

CHS induced fibroblast proliferation/migration, reactive oxygen species-scavenging property, regulation of extracellular matrix synthesis, and autophagy activation. Such enhanced bioactivities of CHS were related to the increase of some key cytokines, including C-X-C motif chemokine ligand 1, interleukin 1 receptor A, interleukin 8, macrophage migration-inhibitory factor, and serpin family E member 1.

CONCLUSION

These findings highlight the implications of cordycepin alteration of the cytokine profile of the HaCaT secretome, which represents a novel biosubstance for the development of wound healing and skin regeneration products.

Cell secretomes for wound healing and tissue regeneration: Next generation acellular based tissue engineered products

Wound represents a significant socioeconomic burden for both affected individuals and as a whole healthcare system. Accordingly, stem cells have garnered attention due to their differentiation capacity and ability to aid tissue regeneration by releasing biologically active molecules, found in the cells' cultivated medium which known as conditioned medium (CM) or secretomes. This acellular approach provides a huge advantage over conventional treatment options, which are mainly used cellular treatment at wound closure. Interestingly, the secretomes contained the cell-secreted proteins such as growth factors, cytokines, chemokines, extracellular matrix (ECM), and small molecules including metabolites, microvesicles, and exosomes. This review aims to provide a general view on secretomes and how it is proven to have great potential in accelerating wound healing. Utilizing the use of secretomes with its secreted proteins and suitable biomaterials for fabrications of acellular skin substitutes can be promising in treating skin loss and accelerate the healing process.

Molekularne mechanizmy działania czynnika transkrypcyjnego FOXN1 w skórze

Artykuł jest przeglądem wyników badań dotyczących funkcji i mechanizmu działania czynnika transkrypcyjnego FOXN1. Lokalizacja FOXN1 u przedstawicieli wszystkich ssaków ogranicza się do nabłonka tylko dwóch organów: skóry i grasicy. W skórze FOXN1 stymuluje różnicowanie się keratynocytów, reguluje proces pigmentacji i bierze udział w rozwoju włosów. W skórze objętej urazem FOXN1 jest zaangażowany w bliznowy proces gojenia poprzez udział w reepitelializacji oraz w procesie przejścia epitelialno-mezenchymalnego (epithelial-mesenchymal transition; EMT). Pozbawione aktywnego czynnika transkrypcyjnego FOXN1 dorosłe myszy (Foxn1-/-) goją urazy skórne w unikalnym, charakterystycznym jedynie dla płodów ssaków, procesie bezbliznowej (scar-free) regeneracji. Analiza porównawcza transkryptomów skóry: dorosłych myszy Foxn1-/- oraz skóry płodów myszy (14. dzień rozwoju płodowego) wykazała istotne podobieństwa w ekspresji genów związanych przede wszystkim z przebudową tkanek, budową cytoszkieletu, gojeniem urazów, odpowiedzią immunologiczną oraz różnicowaniem. Wyniki te wskazują, iż FOXN1 może być głównym elementem szlaku sygnałowego na drodze tzw. punktu tranzycyjnego czyli przejścia z etapu gojenia bezbliznowego (płodowego) do bliznowego (dorosłego) w trakcie rozwoju płodowego.

A Novel Biochemical Study of Anti-Dermal Fibroblast Replicative Senescence Potential of Panax Notoginseng Oligosaccharides

Dermal fibroblast replicative senescence that often occurs in aging skin is characterized by loss of cell proliferative capacity, cell cycle arrest, decreased cell elongation, and decreased synthesis of dermal extracellular matrix (ECM) components. Although Panax notoginseng is known for its effectiveness in alleviating many age-related degenerative diseases, few studies have evaluated P. notoginseng components for efficacy or mechanisms of action in delaying cell replicative senescence. In this study, P. notoginseng oligosaccharides (PNO) were isolated using a stepwise purification procedure involving water extraction and alcohol precipitation followed by DEAE Sepharose Fast Flow column chromatography, preparative high performance liquid chromatography, and size-exclusion chromatography. Monosaccharides detected in PNO constituents included mannose, galactose, and sorbitose in relative molar proportions of 14.2:12.3:1, respectively, aligning with PNO absorption spectrum results resembling typical known spectra for sugars. In vitro, PNO treatment of replicative senescent NIH-3T3 fibroblasts significantly promoted cell vitality, inhibited SA-β-galactosidase (SA-β-Gal) activity, and reduced p16 and p21 protein-level expression. Moreover, PNO treatment of senescent fibroblasts led to a lower proportion of G1 phase cells and higher proportion of S phase cells, while also inducing aging NIH-3T3 cells to migrate and synthesize collagen-I (CoL-I). Mechanistically, PNO treatment up-regulated expression of proliferating cell nuclear antigen (PCNA), cyclin E, cyclin D1, and cyclin-dependent kinase 4 (CDK4) proteins and promoted phosphorylation of MEK, p38, and ERK1/2 to trigger cell cycle progression. Additionally, PNO treatment also up-regulated protein-level expression of TGF-β1 and levels of p-Smad2/3, p-FAK, and p-Pax to trigger CoL-I synthesis and cell migration. Taken together, these findings demonstrate that oligosaccharides purified from P. notoginseng could reverse fibroblast replicative senescence by promoting fibroblast cell proliferation, migration, and CoL-I production.

Impairment of the Hif-1α regulatory pathway in Foxn1-deficient (Foxn1-/- ) mice affects the skin wound healing process

Hypoxia and hypoxia-regulated factors (eg, hypoxia-inducible factor-1α [Hif-1α], factor inhibiting Hif-1α [Fih-1], thioredoxin-1 [Trx-1], aryl hydrocarbon receptor nuclear translocator 2 [Arnt-2]) have essential roles in skin wound healing. Using Foxn1^-/- mice that can heal skin injuries in a unique scarless manner, we investigated the interaction between Foxn1 and hypoxia-regulated factors. The Foxn1^-/- mice displayed impairments in the regulation of Hif-1α, Trx-1, and Fih-1 but not Arnt-2 during the healing process. An analysis of wounded skin showed that the skin of the Foxn1^-/- mice healed in a scarless manner, displaying rapid re-epithelialization and an increase in transforming growth factor β (Tgfβ-3) and collagen III expression. An in vitro analysis revealed that Foxn1 overexpression in keratinocytes isolated from the skin of the Foxn1^-/- mice led to reduced Hif-1α expression in normoxic but not hypoxic cultures and inhibited Fih-1 expression exclusively under hypoxic conditions. These data indicate that in the skin, Foxn1 affects hypoxia-regulated factors that control the wound healing process and suggest that under normoxic conditions, Foxn1 is a limiting factor for Hif-1α.

Effect of Pig-Adipose-Derived Stem Cells' Conditioned Media on Skin Wound-Healing Characteristics In Vitro

The primary mechanism by which adipose-derived stem cells (ASCs) exert their reparative or regenerative potential relies predominantly on paracrine action. Secretory abilities of ASCs have been found to be amplified by hypoxia pre-conditioning. This study investigates the impact of hypoxia (1% O₂) on the secretome composition of pig ASCs (pASCs) and explores the effect of pASCs’ conditioned media (CM) on skin cell functions in vitro and the expression of markers attributed to wound healing. Exposure of pASCs to hypoxia increased levels of vascular endothelial growth factor (VEGF) in CM-Hyp compared to CM collected from the cells cultured in normoxia (CM-Nor). CM-Hyp promoted the migratory ability of pig keratinocytes (pKERs) and delayed migration of pig dermal fibroblasts (pDFs). Exposure of pKERs to either CM-Nor or CM-Hyp decreased the levels of pro-fibrotic indicators WNT10A and WNT11. Furthermore, CM-Hyp enhanced the expression of KRT14, the marker of the basal epidermis layer. In contrast, CM-Nor showed a stronger effect on pDFs manifested by increases in TGFB1, COL1A1, COL3A1, and FN1 mRNA expression. The formation of three-dimensional endothelial cell networks was improved in the presence of CM-Hyp. Overall, our results demonstrate that the paracrine activity of pASCs affects skin cells, and this property might be used to modulate wound healing.

Wnt signaling and the transcription factor Foxn1 contribute to cutaneous wound repair in mice

Aim: The transcription factor Foxn1 is a regulator of scar-ended cutaneous wound healing in mice. However, the link between Foxn1 and Wnt signaling has not been explored in the context of cutaneous repair. Here, we investigate the effects of β-catenin-dependent and -independent Wnt signaling represented by Wnt10a and Wnt11, respectively, in healing of full-thickness cutaneous wounds in C57BL/6 mice. Material and Methods: Quantitative polymerase chain reaction, western blot, and immunostaining were performed to assess the spatial and temporal distribution of Wnt10a, Wnt11, and β-catenin in skin during wound healing. A co-culture system consisting of keratinocytes transfected with an adenoviral vector carrying Foxn1-GFP and dermal fibroblasts (DFs) was employed to determine the influence of epidermal signals on the capacity of DFs to produce extracellular matrix (ECM) proteins in vitro. The levels of types I and III collagen in conditioned media from DFs cultures were examined via enzyme-linked immunosorbent assay. Results: The expression of Wnt10a, Wnt11, and β-catenin increased at post-wounding days 14 and 21 when tissue remodeling occurred. Foxn1::Egfp transgenic mice experiments demonstrated that Wnts were abundant in the epidermis adjacent to the wound margin and to a lesser extent in the dermis. The Wnt10a signal colocalized with Foxn1-eGFP in the epithelial tongue and neo-epidermis during the initial stage of wound healing. Foxn1 overexpression in keratinocytes affected DFs function related to collagen synthesis. Conclusions: Wnt ligands contribute to cutaneous wound repair, predominantly by engagement in ECM maturation. The data indicates a possible relationship between Foxn1 and Wnts in post-traumatic skin tissue.

The complexity of TGFβ/activin signaling in regeneration

The role of transforming growth factor β TGFβ/activin signaling in wound repair and regeneration is highly conserved in the animal kingdom. Various studies have shown that TGF-β/activin signaling can either promote or inhibit different aspects of the regeneration process (i.e., proliferation, differentiation, and re-epithelialization). It has been demonstrated in several biological systems that some of the different cellular responses promoted by TGFβ/activin signaling depend on the activation of Smad-dependent or Smad-independent signal transduction pathways. In the context of regeneration and wound healing, it has been shown that the type of R-Smad stimulated determines the different effects that can be obtained. However, neither the possible roles of Smad-independent pathways nor the interaction of the TGFβ/activin pathway with other complex signaling networks involved in the regenerative process has been studied extensively. Here, we review the important aspects concerning the TGFβ/activin signaling pathway in the regeneration process. We discuss data regarding the role of TGF-β/activin in the most common animal regenerative models to demonstrate how this signaling promotes or inhibits regeneration, depending on the cellular context.

Age, Diet and Epidermal Signaling Modulate Dermal Fibroblasts' Adipogenic Potential

The recognition of a distinct fat depot, the dermal white adipose tissue (dWAT), points out the complexity of the interaction among skin resident cells: keratinocytes, dermal fibroblasts (DFs) and adipocytes in response to physiological (diet, age) and pathological (injury) stimulations. dWAT has been recognized as a significant contributor to thermoregulation, hair cycle, immune response, wound healing and scarring. In this study, we examined age- and diet-related changes in dWAT modulation and DFs' adipogenic potential. The data showed that diet modulates dWAT expansion predominantly by hypertrophy, whereas age affects the pool of adipocyte progenitor cells in the skin indicating its role in dWAT hyperplasia. Analysis of DFs' migratory abilities in the model of skin explants isolated from the skin of young, old, low (LFD)- or high (HFD)-fat diet C56BL/6 mice revealed that HFD, regardless of animal age has the most profound stimulatory impact of DF migration. We determined that the adipogenic potential of DFs is comparable to stromal vascular fraction (SVF) of inguinal fat depot and ear mesenchymal stem cells (EMSC). We also showed the stimulatory role of epidermally expressed transcription factor Foxn1 on adipogenic signaling: bone morphogenetic protein 2 (Bmp2) and insulin-like growth factor 2 (Igf2) in keratinocytes.

The effect of hypoxia on the proteomic signature of pig adipose-derived stromal/stem cells (pASCs)

Human adipose-derived stem cells (ASCs) have potential to improve wound healing; however, their equivalents from domestic animals have received less attention as an alternative cell-based therapy for animals or even humans. Hypoxia is essential for maintaining stem cell functionality in tissue-specific niches. However, a cellular response to low oxygen levels has not been demonstrated in pig ASCs. Hence, the goal of our study was to characterize ASCs isolated from the subcutaneous fat of domestic pigs (pASCs) and examine the effect of hypoxia on their proteome and functional characteristics that might reproduce pASCs wound healing ability. Analysis of immunophenotypic and functional markers demonstrated that pASCs exhibited characteristics of mesenchymal stem cells. Proteomic analysis revealed 70 differentially abundant proteins between pASCs cultured under hypoxia (1% O₂) or normoxia (21% O₂). Among them, 42 proteins were enriched in the cells exposed to low oxygen, whereas 28 proteins showed decrease expression following hypoxia. Differentially expressed proteins were predominantly involved in cell metabolism, regulation of focal and intracellular communication, and attributed to wound healing. Functional examination of hypoxic pASCs demonstrated acquisition of contractile abilities in vitro. Overall, our results demonstrate that hypoxia pre-conditioning impacts the pASC proteome signature and contractile function in vitro and hence, they might be considered for further cell-based therapy study on wound healing.

Evidence-based therapy in hypertrophic scars: An update of a systematic review

Hypertrophic scars are still a major burden for numerous patients, especially after burns. Many treatment options are available; however, no evidence-based treatment protocol is available with recommendations mostly emerging from experience or lower quality studies. This review serves to discuss the currently available literature. A systematic review was performed and the databases PubMed and Web of Science were searched for suitable publications. Only original articles in English that dealt with the treatment of hypertrophic scars in living humans were analyzed. Further, studies with a level of evidence lower than 1 as defined by the American Society of Plastic Surgeons were excluded. After duplicate exclusion, 1638 studies were screened. A qualitative assessment yielded 163 articles eligible for evidence grading. Finally nine studies were included. Four of them used intralesional injections, four topical therapeutics and one assessed the efficacy of CO₂ -laser. Intralesional triamcinolone + fluorouracil injections, and topical pressure and/or silicone therapy revealed significant improvements in terms of scar height, pliability, and pigmentation. This systematic review showed that still few high-quality studies exist to evaluate therapeutic means and their mechanisms for hypertrophic scars. Among these, most of them assessed the efficacy of intralesional triamcinolone injections with the same treatment protocol. Intralesional injection appears to be the best option for hypertrophic scar treatment. Future studies should focus on a possible optimization of infiltrative therapies, consistent end-point evaluations, adequate follow-up periods, and possibly intraindividual treatments.

Cutaneous wound healing in aged, high fat diet-induced obese female or male C57BL/6 mice

Since there are limited studies analyzing the impact of age, sex and obesity on cutaneous repair, the current study evaluated excisional skin wound healing as a function of age, sex and diet in C57BL/6 mice subjected to either low (LFD) or high (HFD) fat diet. Older mice accumulated increased body fat relative to younger mice under HFD. Skin wound healing at particular stages was affected by age in the aspect of Tgfβ-1, MCP-1, Mmp-9 and Mmp-13 expression. The most profound, cumulative effect was observed for the combination of two parameters: age and sex. While skin of younger males displayed extremely high collagen 1 and collagen 3 expression, younger females showed exceptionally high Mmp-13 expression at day 3 and 7 after injury. Diet as a single variable modified the thickness of dermis due to increased dermal White Adipose Tissue (dWAT) accumulation in mice fed HFD. The combination of age and diet affected the re-epithelialization and inflammatory response of injured skin. Overall, our data indicate that age has the most fundamental impact although all components (age, sex and diet) contribute to skin repair.

Efficacy and Safety of Pirfenidone in Patients with Second-Degree Burns: A Proof-of-Concept Randomized Controlled Trial

OBJECTIVE

Several studies suggest that pirfenidone may have a potential off-label use for wound healing. However, the effectiveness of this medication in patients with burns remains uncertain. Accordingly, investigators sought to assess wound re-epithelialization in patients with second-degree burns after adding pirfenidone to usual care.

DESIGN AND SETTING

Single-center pilot, proof-of-concept, single-blind randomized controlled trial.

PATIENTS AND INTERVENTION

Eight patients with second-degree burns were treated with occlusive hydrocolloid dressings and were randomly allocated to receive either no additional treatment or pirfenidone.

OUTCOME MEASURES

The primary outcome of the study was to evaluate wound healing between groups based on the thickness of the re-epithelialized epidermis at day 7. Secondary outcomes were to qualitatively assess the development of fibrotic tissue in the dermis, anomalies in the basal membrane, and the development of collagen fibers by histologic analysis. Liver and renal functions were measured daily to assess the overall safety of oral pirfenidone.

MAIN RESULTS

Patients treated with pirfenidone showed a remarkable improvement in wound re-epithelialization at day 7 (148.98 ± 13.64 vs 119.27 ± 15.55 μm; P = .029; 95% confidence interval, 4.14-55.29). Histologic evaluations showed less wound fibrosis in the pirfenidone group.

CONCLUSIONS

A decrease in wound healing time by enhancing wound re-epithelialization was observed with pirfenidone. Larger clinical trials are needed to reach more reliable conclusions.

Insulin-like growth factor (IGF)-II- mediated fibrosis in pathogenic lung conditions

Type 2 insulin-like growth factor (IGF-II) levels are increased in fibrosing lung diseases such as idiopathic pulmonary fibrosis (IPF) and scleroderma/systemic sclerosis-associated pulmonary fibrosis (SSc). Our goal was to investigate the contribution of IGF receptors to IGF-II-mediated fibrosis in these diseases and identify other potential mechanisms key to the fibrotic process. Cognate receptor gene and protein expression were analyzed with qRT-PCR and immunoblot in primary fibroblasts derived from lung tissues of normal donors (NL) and patients with IPF or SSc. Compared to NL, steady-state receptor gene expression was decreased in SSc but not in IPF. IGF-II stimulation differentially decreased receptor mRNA and protein levels in NL, IPF, and SSc fibroblasts. Neutralizing antibody, siRNA, and receptor inhibition targeting endogenous IGF-II and its primary receptors, type 1 IGF receptor (IGF1R), IGF2R, and insulin receptor (IR) resulted in loss of the IGF-II response. IGF-II tipped the TIMP:MMP balance, promoting a fibrotic environment both intracellularly and extracellularly. Differentiation of fibroblasts into myofibroblasts by IGF-II was blocked with a TGFβ1 receptor inhibitor. IGF-II also increased TGFβ2 and TGFβ3 expression, with subsequent activation of canonical SMAD2/3 signaling. Therefore, IGF-II promoted fibrosis through IGF1R, IR, and IGF1R/IR, differentiated fibroblasts into myofibroblasts, decreased protease production and extracellular matrix degradation, and stimulated expression of two TGFβ isoforms, suggesting that IGF-II exerts pro-fibrotic effects via multiple mechanisms.

Recent Advances in Understanding FOXN3 in Breast Cancer, and Other Malignancies

FOXN3 (forkhead box N3; CHES1: check point suppressor 1) belongs to the forkhead box (FOX) protein family. FOXN3 displays transcriptional inhibitory activity, and is involved in cell cycle regulation and tumorigenesis. FOXN3 is a tumor suppresser and alterations in FOXN3 are found in of a variety of cancers including melanoma, osteosarcoma, and hepatocellular carcinoma. While the roles of FOXN3 role in some cancers have been explored, its role in breast cancer remains unclear. Here we describe current state of knowledge of FOXN3 functions, and focus on its roles (known and potential) in breast cancer.

Effect of transforming growth factor -β1 on α-smooth muscle actin and collagen expression in equine endometrial fibroblasts

Transforming growth factor (TGF)-β1 not only regulates cell growth, development, and tissue remodeling, but it also participates in the pathogenesis of tissue fibrosis. In the equine endometrium, the concentration of TGF-β1 is correlated with endometrosis (equine endometrial fibrosis). In other tissues, TGF-β1 induces differentiation of many cell types into myofibroblasts. These cells are characterized by α-smooth muscle actin (α-SMA) expression and an ability to deposit excessive amounts of extracellular matrix (ECM) components. The aim of the study was to determine whether TGF-β1 plays a role in the development of equine endometrosis. In Exp. 1, endometrial expression of α-SMA in different stages of endometrosis was determined. In endometrial tissues from the mid luteal phase (n = 6 for each stages of endometrosis) and the follicular phase of the estrous cycle (n = 5 for each stages of endometrosis), mRNA transcription and protein expression of α-Sma were evaluated by Real-time PCR and Western-blot, respectively. The α-Sma mRNA transcription and protein expression levels were correlated with the severity of endometrosis (P < 0.05). In both phases of the estrous cycle, α-SMA protein expression was up-regulated in final stage of endometrosis compared to initial stage (P < 0.05). In Exp. 2, the dose- and time-dependent effects of TGF-β1 on expression of α-SMA and ECM components were determined, as well as cell proliferation of equine fibroblasts. Equine endometrial fibroblasts (n = 6, Kenney and Doig category I) were stimulated with vehicle or TGF-β1 (1, 5, 10 ng/ml) for 24, 48 or 72 h. Then, mRNA transcription of α-Sma, collagen type I (Col1a1), collagen type III (Col3a1) and fibronectin 1 (Fn1) were determined by Real-time PCR. The production of ECM components was determined by ELISA. Transforming growth factor-β1 increased the mRNA transcription of α-Sma and ECM components in a dose- and time-dependent manner in cultured endometrial fibroblasts (P < 0.05). Additionally, TGF-β1 at a dose of 10 ng/ml increased α-SMA protein expression and COL1, COL3, FN production after 72 h of stimulation (P < 0.05). The data showed a positive linkage between the presence of myofibroblasts and severity of endometrosis. We conclude that TGF-β1 may participate in pathological fibrotic changes in equine endometrial tissue by induction of myofibroblast differentiation, increased production of ECM components and fibroblast proliferation.

Foxn1 in Skin Development, Homeostasis and Wound Healing

Intensive research effort has focused on cellular and molecular mechanisms that regulate skin biology, including the phenomenon of scar-free skin healing during foetal life. Transcription factors are the key molecules that tune gene expression and either promote or suppress gene transcription. The epidermis is the source of transcription factors that regulate many functions of epidermal cells such as proliferation, differentiation, apoptosis, and migration. Furthermore, the activation of epidermal transcription factors also causes changes in the dermal compartment of the skin. This review focuses on the transcription factor Foxn1 and its role in skin biology. The regulatory function of Foxn1 in the skin relates to physiological (development and homeostasis) and pathological (skin wound healing) conditions. In particular, the pivotal role of Foxn1 in skin development and the acquisition of the adult skin phenotype, which coincides with losing the ability of scar-free healing, is discussed. Thus, genetic manipulations with Foxn1 expression, specifically those introducing conditional Foxn1 silencing in a Foxn1+/+ organism or its knock-in in a Foxn1−/− model, may provide future perspectives for regenerative medicine.