Fetal Keratinocytes Research Articles

Spatiotemporal distribution of PTEN before directed cell migration in monolayers.

The intracellular distribution of phosphatase and tensin homolog (PTEN) is closely related to directed cell migration. In single cells, PTEN accumulates at the rear of the cell before and during directed migration; however, the spatiotemporal distribution of PTEN in confluent cell monolayers, particularly before directed migration, remains unclear. In this study, we wounded a cell in confluent fetal rat skin keratinocytes (FRSKs) and examined the dynamics of PTEN in the cells adjacent to the wounded cell. In contrast to single-cell migration, we found that PTEN translocated to the nucleus before the beginning of directed migration. This nuclear translocation of PTEN did not occur in disconnected cells, and it was also suppressed by importin-β inhibitor and actin inhibitor. When the nuclear localization of PTEN was inhibited by an importin-β inhibitor, cell elongation in the direction of migration was also significantly inhibited. Our results indicate that PTEN translocation is induced by the disruption of cell-cell adhesion and requires the involvement of importin-β and actin cytoskeleton signaling. In addition, phosphatidylinositol 3,4,5-triphosphate (PIP3) may regulate PTEN distribution through its localized accumulation at the cell edge. Our findings suggest that the translocation of PTEN is crucial for directed cell migration and for responding to mechanical environmental changes in confluent cell monolayers.

How do the skin barrier and microbiome adapt to the extra-uterine environment after birth? Implications for the clinical practice.

The multiple protective functions of the skin derive from the interactions between epithelial skin and immune cells as well as the commensal microbiota. Developed in the last trimester of intra-uterine life, the skin barrier adapts dynamically after birth. Specific differences in the structure and physiology have been disclosed between infant and adult skin. The stratum corneum of infants is thinner and structured by thicker corneocytes with a more anisotropic surface in comparison to adult skin. Lower levels of the natural moisturizing factor and its constituents, together with the increased protease activity in the epidermis result in dry baby skin and ongoing adaptation of the desquamation to the extra-uterine environment. Infant epidermis is characterized by an accelerated proliferation rate and clinically competent permeability barrier in term neonates, despite the higher baseline values of transepidermal water loss in infants. The skin surface of newborns is less acidic, which could increase susceptibility to diaper and atopic dermatitis. Immediately after birth, skin is colonized by commensal bacteria-a process dependent on the mode of delivery and of major importance for the maturation of the immune system. Skin bacterial diversity and dysbiosis have been related to different pathology such as atopic and seborrheic dermatitis. This paper focuses on the ongoing structural, functional and biochemical adaptation of the human skin barrier after birth. We discuss the interactions on the 'skin barrier/ microbiota/ immune system' axis and their role in the development of competent functional integrity of the epidermal barrier.

Proteasome-mediated degradation of keratins 7, 8, 17 and 18 by mutant KLHL24 in a foetal keratinocyte model: Novel insight in congenital skin defects and fragility of epidermolysis bullosa simplex with cardiomyopathy

Epidermolysis bullosa simplex (EBS) with cardiomyopathy (EBS-KLHL24) is an EBS subtype caused by dominantly inherited, gain-of-function mutations in the gene encoding for the ubiquitin-ligase KLHL24, which addresses specific proteins to proteasomal degradation. EBS-KLHL24 patients are born with extensive denuded skin areas and skin fragility. Whilst skin fragility rapidly ameliorates, atrophy and scarring develop over time, accompanied by life-threatening cardiomyopathy. To date, pathogenetic mechanisms underlying such a unique disease phenotype are not fully characterized. The basal keratin 14 (K14) has been indicated as a KLHL24 substrate in keratinocytes. However, EBS-KLHL24 pathobiology cannot be determined by the mutation-enhanced disruption of K14 alone, as K14 is similarly expressed in foetal and postnatal epidermis and its protein levels are preserved both in vivo and in vitro disease models. In this study, we focused on foetal keratins as additional KLHL24 substrates. We showed that K7, K8, K17 and K18 protein levels are markedly reduced via proteasome degradation in normal foetal keratinocytes transduced with the mutant KLHL24 protein (ΔN28-KLHL24) as compared to control cells expressing the wild-type form. In addition, heat stress led to keratin network defects and decreased resilience in ΔN28-KLHL24 cells. The KLHL24-mediated degradation of foetal keratins could contribute to congenital skin defects in EBS-KLHL24. Furthermore, we observed that primary keratinocytes from EBS-KLHL24 patients undergo accelerated clonal conversion with reduced colony forming efficiency (CFE) and early replicative senescence. Finally, our findings pointed out a reduced CFE in ΔN28-KLHL24-transduced foetal keratinocytes as compared to controls, suggesting that mutant KLHL24 contributes to patients’ keratinocyte clonogenicity impairment.

STAT3 Partly Inhibits Cell Proliferation via Direct Negative Regulation of FST Gene Expression.

Follistatin (FST) is a secretory glycoprotein and belongs to the TGF-β superfamily. Previously, we found that two single nucleotide polymorphisms (SNPs) of sheep FST gene were significantly associated with wool quality traits in Chinese Merino sheep (Junken type), indicating that FST is involved in the regulation of hair follicle development and hair trait formation. The transcription regulation of human and mouse FST genes has been widely investigated, and many transcription factors have been identified to regulate FST gene. However, to date, the transcriptional regulation of sheep FST is largely unknown. In the present study, genome walking was used to close the genomic gap upstream of the sheep genomic FST gene and to obtain the FST gene promoter sequence. Transcription factor binding site analysis showed sheep FST promoter region contained a conserved putative binding site for signal transducer and activator of transcription 3 (STAT3), located at nucleotides −423 to −416 relative to the first nucleotide (A, +1) of the initiation codon (ATG) of sheep FST gene. The dual-luciferase reporter assay demonstrated that STAT3 inhibited the FST promoter activity and that the mutation of the putative STAT3 binding site attenuated the inhibitory effect of STAT3 on the FST promoter activity. Additionally, chromatin immunoprecipitation assay (ChIP) exhibited that STAT3 is directly bound to the FST promoter. Cell proliferation assay displayed that FST and STAT3 played opposite roles in cell proliferation. Overexpression of sheep FST significantly promoted the proliferation of sheep fetal fibroblasts (SFFs) and human keratinocyte (HaCaT) cells, and overexpression of sheep STAT3 displayed opposite results, which was accompanied by a significantly reduced expression of FST gene (P < 0.05). Taken together, STAT3 directly negatively regulates sheep FST gene and depresses cell proliferation. Our findings may contribute to understanding molecular mechanisms that underlie hair follicle development and morphogenesis.

Syntaxin 1A Gene Is Negatively Regulated in a Cell/Tissue Specific Manner by YY1 Transcription Factor, Which Binds to the -183 to -137 Promoter Region Together with Gene Silencing Factors Including Histone Deacetylase.

The HPC-1/syntaxin 1A (Stx1a) gene, which is involved in synaptic transmission and neurodevelopmental disorders, is a TATA-less gene with several transcription start sites. It is activated by the binding of Sp1 and acetylated histone H3 to the −204 to +2 core promoter region (CPR) in neuronal cell/tissue. Furthermore, it is depressed by the association of class 1 histone deacetylases (HDACs) to Stx1a–CPR in non-neuronal cell/tissue. To further clarify the factors characterizing Stx1a gene silencing in non-neuronal cell/tissue not expressing Stx1a, we attempted to identify the promoter region forming DNA–protein complex only in non-neuronal cells. Electrophoresis mobility shift assays (EMSA) demonstrated that the −183 to −137 OL2 promoter region forms DNA–protein complex only in non-neuronal fetal rat skin keratinocyte (FRSK) cells which do not express Stx1a. Furthermore, the Yin-Yang 1 (YY1) transcription factor binds to the −183 to −137 promoter region of Stx1a in FRSK cells, as shown by competitive EMSA and supershift assay. Chromatin immunoprecipitation assay revealed that YY1 in vivo associates to Stx1a–CPR in cell/tissue not expressing Stx1a and that trichostatin A treatment in FRSK cells decreases the high-level association of YY1 to Stx1a-CPR in default. Reporter assay indicated that YY1 negatively regulates Stx1a transcription. Finally, mass spectrometry analysis showed that gene silencing factors, including HDAC1, associate onto the −183 to −137 promoter region together with YY1. The current study is the first to report that Stx1a transcription is negatively regulated in a cell/tissue-specific manner by YY1 transcription factor, which binds to the −183 to −137 promoter region together with gene silencing factors, including HDAC.

IMMU-36. HIGH AFFINITY CHIMERIC ANTIGEN RECEPTOR WITH CROSS-REACTIVITY TO CLINICALLY-RELEVANT EGFR MUTATED PROTEINS

Abstract Tumor heterogeneity is one of the key reasons for therapeutic failure in Glioblastoma (GBM). Our chimeric antigen receptor (CAR) T cell clinical trial (NCT02209376) against Epidermal growth factor receptor (EGFR) variant III (EGFRvIII) demonstrated successful trafficking of T cells across the blood brain barrier into GBM active tumor sites. However, CART cell infiltration was associated with a selective loss of EGFRvIII+ tumor cells and upregulation of immunosuppressive molecules. Post-CAR T treated tumor specimens showed continued presence of EGFR amplification and oncogenic EGFR extracellular domain (ECD) missense mutations. To study this further We generated two structurally different CARs by fusing the scFv of mAb806 to 4-1BB and Killer immunoglobulin like receptor (KIR) co-stimulatory domains. Both 4-1BB and KIR based EGFR806 CAR T cells specifically lysed tumor cells and secreted cytokines when co-cultured with U87-MG (expressing low levels of EGFR) and U87-MG EGFR (U87-MG transduced with EGFR wild type for amplified background) cell lines and engineered to ectopically express targeted EGFR-ECD missense mutations and EGFRvIII. Unlike EGFR-specific cetuximab based CAR, EGFR-806CART cells did not kill EGFR wild type expressing fetal brain primary astrocytes and keratinocytes in vitro. We further evaluated the in vivo efficacy of 806-CARs and EGFRvIII CART currently in clinic in NSG mice. While EGFRvIII CART cells cleared EGFRvIII+ tumors alone 806 CART cells controlled EGFRvIII, amplified EGFR and EGFRR108K-mutant bearing tumors. KIR-CAR treated tumors are GVHD free and enhanced survival compared to 4-1BB based CARs. The broad specificity of EGFR806 CART cells to amplified EGFR and its mutant variants gives us the potential to clear various forms of EGFR. The enhanced anti-tumor efficacy by KIR based CAR in vivo setting provides us with additional therapeutic options.

Abstract 6596: High affinity chimeric antigen receptors with cross reactivity to clinically relevant EGFR mutated proteins

Abstract Introduction: Glioblastoma (GBM) is malignant and aggressive brain tumor with a median overall survival of 14.6 months, despite the development of new treatments. Chimeric Antigen Receptor (CAR) modified T cells are powerful new class of immune based therapies that have shown a high rate of long term durable response in CD19 expressing B-cell malignancies. However, this success has yet to be translated to solid tumors, in part due to a lack of surface antigens specifically expressed on tumor cells while not present on normal tissue and an immunosuppressive tumor microenvironment. Approximately 60% of GBMs contain a mutation, rearrangement, splicing alteration, and/or amplification of EGFR. Investigation of 411 GBM patient samples from University of Pennsylvania identified EGFR amplification in 38% of cases and EGFRvIII in 25% of cases and most common oncogenic missense mutations in extracellular domain (ECD) A289D/T/V, R108G/K, and G598V in 12-13% of cases. ECD missense mutations are associated with increased invasiveness aided by ligand independent activation of receptor and decreased patient survival compared to patients that are wild type EGFR at R108, A289 and G59V locus. Methods: We generated two structurally different CARs by fusing the scFv of mAb806 to 4-1BB and Killer immunoglobulin like receptor (KIR) co-stimulatory domains. mAb806 recognizes a conformationally exposed epitope of wild-type EGFR when it is overexpressed on tumor cells or in the presence of oncogenic mutations such as EGFRvIII. We tested in vitro cytolytic activity of 806-EGFR-CART cells against U87-MG (expressing low levels of EGFR) and U87-MG EGFR (U87-MG parental cell line transduced with EGFR wild type for amplified background) cell lines. These lines were engineered to ectopically express targeted EGFR-ECD missense mutations and EGFRvIII. Results: Both 4-1BB and KIR based EGFR806 CAR T cells specifically lysed tumor cells, proliferated, and secreted cytokines when co-cultured with target-expressing cell lines. To test exclusive specificity of EGFR806 CART to targeted mutations, K562 cells were transduced with EGFR-ECD mutations and co-cultured with 4-1BB and KIR CART cells. While the EGFR806 lysed K562 cells expressing wild type EGFR, EGFR-ECD Mutants, and EGFRvIII, it did not demonstrate any activity against K562-Parental cells. Unlike EGFR-specific cetuximab based CAR, EGFR-806CART cells did not kill EGFR wild type expressing fetal brain astrocytes and keratinocytes in vitro. We further evaluated the in vivo efficacy of CARs in NSG mice by injecting U87-MG, U87-MG EGFR and U87-MG EGFR expressing EGFRvIII subcutaneously and assessed tumor burden and mice survival. Though both 4-1BB and KIR based EGFR806 CART cells control tumor growth, KIR based CAR outperformed 4-1BB based CAR in terms of tumor burden and improved mice survival. Conclusion: Though our CART clinical trial for EGFRvIII positive recurrent GBM patients demonstrated CART therapy is safe and CART cells are able to successfully traffic to regions of active GBM, antigen loss and tumor heterogeneity resulted in limited therapeutic success. Broad specificity of EGFR806 CART cells to Amplified EGFR, EGFRvIII and EGFR-ECD mutants gives us the potential to clear various forms of EGFR. The enhanced anti-tumor efficacy by KIR based CAR in vivo setting provides us with additional therapeutic options for GBM. Citation Format: Radhika Thokala, Zev Binder, Yibo Yin, Michael Milone, Donald M. Orourke. High affinity chimeric antigen receptors with cross reactivity to clinically relevant EGFR mutated proteins [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6596.

Low-expression of microRNA-203a in mid-gestational human fetal keratinocytes contributes to cutaneous scarless wound healing by targeting Tenascin-C

Low-expression of microRNA-203a in mid-gestational human fetal keratinocytes contributes to cutaneous scarless wound healing by targeting Tenascin-C

Low-expression of microRNA-203a in mid-gestational human fetal keratinocytes contributes to cutaneous scarless wound healing by targeting Tenascin-C

Low-expression of microRNA-203a in mid-gestational human fetal keratinocytes contributes to cutaneous scarless wound healing by targeting Tenascin-C

Foetal skin cells in wound healing: a promising tool for clinical application.

The skin is the first protective barrier of our body. Wound healing is therefore an essential mechanism. However, this phenomenon can be impaired when wounds are too large or chronic, for example, in diabetes. Interestingly, adult skin heals with scars, whereas foetuses present scarless regeneration. The objective of this review is to highlight the difference in healing pathways between foetal and adult skin and to present the recent therapeutic strategies envisaged using foetal properties in the clinic. The main features that distinguish foetal wound healing from adult wound healing are less tissue inflammation, faster reepithelialisation, and less contraction of the neodermis, allowing foetal tissues to regenerate. Recently, new therapies in regenerative medicine have been introduced using these foetal properties. For the first time, our team has developed CICAFAST, an innovative dressing composed of foetal keratinocytes and fibroblasts, which has been tested on a skin graft donor site in a clinical Phase 1/2 trial.

CICAFAST: comparison of a biological dressing composed of fetal fibroblasts and keratinocytes on a split-thickness skin graft donor site versus a traditional dressing: a randomized controlled trial

BackgroundWound repair is one of the most complex biological processes of human life. Allogeneic cell-based engineered skin substitutes provide off-the-shelf temporary wound coverage and act as biologically active dressings, releasing growth factors, cytokines and extracellular matrix components essential for proper wound healing. However, they are susceptible to immune rejection and this is their major weakness.Thanks to their low immunogenicity and high effectiveness in regeneration, fetal skin cells represent an attractive alternative to the commonly used autologous and allogeneic skin grafts.Methods/designWe developed a new dressing comprising a collagen matrix seeded with a specific ratio of active fetal fibroblasts and keratinocytes. These produce a variety of healing growth factors and cytokines which will increase the speed of wound healing and induce an immunotolerant state, with a slight inflammatory reaction and a reduction in pain.The objective of this study is to demonstrate that the use of this biological dressing for wound healing at the split-thickness skin graft (STSG) donor site, reduces the time to healing, decreases other co-morbidities, such as pain, and improves the appearance of the scar.This investigation will be conducted as part of a randomized study comparing our new biological dressing with a conventional treatment in a single patient, thus avoiding the factors that may influence the healing of a graft donor site.DiscussionThis clinical trial should enable the development of a new strategy for STSG donor-wound healing based on a regenerative dressing. The pain experienced in the first few days of STSG healing is well known due to the exposure of sensory nerve endings. Reducing this pain will also reduce analgesic drug intake and the duration of sick leave.Our biological dressing will meet the essential need of surgeons to “re-crop” from existing donor sites, e.g., for thermal-burn patients. By accelerating healing, improving the appearance of the scar and reducing pain, we hope to improve the conditions of treatment for skin grafts.Trial registrationClinicalTrials.gov, ID: NCT03334656. Registered on 7 November 2017.

Genetic and genomic studies of pathogenic EXOSC2 mutations in the newly described disease SHRF implicate the autophagy pathway in disease pathogenesis.

Missense mutations in the RNA exosome component exosome component 2 (EXOSC2), also known as ribosomal RNA-processing protein 4 (RRP4), were recently identified in two unrelated families with a novel syndrome known as Short stature, Hearing loss, Retinitis pigmentosa and distinctive Facies (SHRF, #OMIM 617763). Little is known about the mechanism of the SHRF pathogenesis. Here we have studied the effect of mutations in EXOSC2/RRP4 in patient-derived lymphoblasts, clustered regularly interspaced short palindromic repeats (CRISPR)-generated mutant fetal keratinocytes and Drosophila. We determined that human EXOSC2 is an essential gene and that the pathogenic G198D mutation prevents binding to other RNA exosome components, resulting in protein and complex instability and altered expression and/or activities of critical genes, including those in the autophagy pathway. In parallel, we generated multiple CRISPR knockouts of the fly rrp4 gene. Using these flies, as well as rrp4 mutants with Piggy Bac (PBac) transposon insertion in the 3'UTR and RNAi flies, we determined that fly rrp4 was also essential, that fly rrp4 phenotypes could be rescued by wild-type human EXOSC2 but not the pathogenic form and that fly rrp4 is critical for eye development and maintenance, muscle ultrastructure and wing vein development. We found that overexpression of the transcription factor MITF was sufficient to rescue the small eye and adult lethal phenotypes caused by rrp4 inhibition. The autophagy genes ATG1 and ATG17, which are regulated by MITF, had similar effect. Pharmacological stimulation of autophagy with rapamycin also rescued the lethality caused by rrp4 inactivation. Our results implicate defective autophagy in SHRF pathogenesis and suggest therapeutic strategies.

Human Novel MicroRNA Seq-915_x4024 in Keratinocytes Contributes to Skin Regeneration by Suppressing Scar Formation

Early in gestation, wounds in fetal skin heal by regeneration, in which microRNAs play key roles. Seq-915_x4024 is a novel microRNA candidate confirmed by deep sequencing and mirTools 2.0. It is highly expressed in fetal keratinocytes during early gestation. Using an in vitro wound-healing assay, Transwell cell migration assay, and MTS proliferation assay, we demonstrated that keratinocytes overexpressing seq-915_x4024 exhibited higher proliferative activity and the ability to promote fibroblast migration and fibroblast proliferation. These characteristics of keratinocytes are the same biological behaviors as those of fetal keratinocytes, which contribute to skin regeneration. In addition, seq-915_x4024 suppressed the expression of the pro-inflammatory markers TNF-α, IL-6, and IL-8 and the pro-inflammatory chemokines CXCL1 and CXCL5. We also demonstrated that seq-915_x4024 regulates TGF-β isoforms and the extracellular matrix. Moreover, using an in vivo wound-healing model, we demonstrated that overexpression of seq-915_x4024 in keratinocytes suppresses inflammatory cell infiltration and scar formation. Using bioinformatics analyses, luciferase reporter assays, and western blotting, we further demonstrated that Sar1A, Smad2, TNF-α, and IL-8 are direct targets of seq-915_x4024. Furthermore, the expression of phosphorylated Smad2 and Smad3 was reduced by seq-915_x4024. Seq-915_x4024 could be used as an anti-fibrotic factor for the treatment of wound healing.

Evaluation of the Effect of Plant Mixture Ethanol Extracts Containing Biota orientalis L. Extract on Suppression of Sebum in Cultured Sebocytes and on Stimulation of Growth of Keratinocytes Co-cultured with Hair Papilla Cells

Biota orientalis L. leaf extract (BOLE) is used medically to improve strength and arrest hemorrhage. In China, BOLE has been used in traditional medicine for its antibacterial properties and for hair restoration. In this study, we investigated the mechanism of hair restoration by BOLE from the point of view of the sebum suppressant effect and hair loss prevention. BOLE at 25 or 50 μg/mL final concentrations, a hair growth plant ethanol extract (HGPEE), and a hair growth plant water extract (HGPWE) (the latter two each containing BOLE and other plant compounds), were used to study: (1) the sebum suppressant effect in sebocytes from normal golden hamster ear pinna origin; (2) the effect on the growth of human fetal epidermal keratinocytes; and (3) the effect on gene expression related to hair growth stimulation, with (2) and (3) studied in human fetal epidermal keratinocytes and hair papilla cells. BOLE had a sebum depletion effect in cultured sebocytes; moreover, the amounts of mRNA of the hair growth factors, KGF, VEGF, and G3PDH analyzed by real-time polymerase chain reaction in human hair papilla cells were increased by HGPEE. The amount of mRNA of Wnt10b in cultured epidermal keratinocytes was increased by the addition of BOLE, and the growth of the cultured epidermal keratinocytes was promoted by HGPEE in a two-layer culture system of hair papilla cells and epidermal keratinocytes. HGPEE had a hair growth promotion/hair restoration effect and a sebum suppression effect. Hair restorers containing HGPEE may be useful for stimulating hair growth and suppressing excess scalp sebum in males and females.

Suppressive effects of human fetal keratinocytes on the proliferation, differentiation and extracellular matrix synthesis of human hypertrophic scar fibroblasts invitro.

A hypertrophic scar is characterized by fibroblast proliferation and excessive extracellular matrix deposition. Emerging evidence has revealed that fetal keratinocytes (KCs) contribute to scarless wound healing. However, the association between fetal keratinocytes and hypertrophic scarring remains unclear. In the present study, human KCs of different gestational ages were isolated and co-cultured with human hypertrophic scar fibroblasts (HSFbs) or normal skin fibroblasts. Gene expression and protein levels of fibronectin, collagen 1and α-smooth muscle actin in the fibroblasts were measured by reverse transcription-quantitative polymerase chain reaction and western blot analyses. It was observed that fetal KCs significantly inhibited the proliferation of HSFbs in vitro. Fetal keratinocytes also affected the expression of fibronectin, collagen 1 and α-smooth muscle actin in HSFbs. In addition, miR-940 may modulate the suppressive effects of fetal KCs on the cell proliferation, differentiation and extracellular matrix synthesis of HSFbs by directly targeting transforming growth factor-β1. Taken together, the results of the present study provide evidence to support the potential use of fetal KCs for cell-based therapeutic grafting in the prevention of hypertrophic scarring.

MicroRNA-149 contributes to scarless wound healing by attenuating inflammatory response.

A fibrotic or pathological scar is an undesired consequence of skin wound healing and may trigger a series of problems. An attenuated inflammatory response is a significant characteristic of fetal skin wound healing, which can contribute to the scarless healing of fetal skin. According to deep sequencing data, microRNA‑149 (miR‑149) expression was increased in mid-gestational compared with that in late‑gestational fetal skin keratinocytes. It was demonstrated that overexpression of miR‑149 in HaCaT cells can downregulate the expression of pro‑inflammatory cytokines interleukin (IL)‑1α, IL‑1β, and IL‑6 at basal levels and in inflammatory conditions. Furthermore, miR‑149 was revealed to indirectly accelerate transforming growth factor‑β3 and collagen type III expression in fibroblasts, which are essential cells in extracellular matrix remodeling. In a rat skin wound model, miR‑149 improved the quality of the arrangement of collagen bundles and reduced inflammatory cell infiltration during skin wound healing. These results indicate that miR‑149 may be a potential regulator in improving the quality of skin wound healing.

Successful grafting of tissue-engineered fetal skin

Fetal repair of spina bifida results in improved outcomes and has therefore become a standard clinical procedure in some highly specialized centers. However, optimization of the procedure technique and timing is needed. Both might be achieved by facilitating the procedure using laboratory-grown fetal skin substitutes. The aim of this study was therefore to test in vivo the suitability of such a fetal skin substitute for an in utero application. Collagen-based hydrogels containing fetal ovine fibroblasts were seeded with fetal ovine keratinocytes and transplanted on immuno-incompetent nu/nu rats. After 3weeks, grafts were harvested and analyzed histologically and by immunohistochemistry. Laboratory-grown fetal ovine dermo-epidermal skin substitutes showed successful engraftment at 3weeks. Histologically, grafts revealed a neo-dermis populated by fibroblasts and with ingrowth of vessels, and an epidermis with an adult-like, mature appearance depicting clearly basal, spinous, granular, and a corneal layer. Immunostaining confirmed a physiologically organized epidermis. Fetal dermo-epidermal skin substitutes of ovine origin can successfully be grafted in vivo. In a next step, we will have to test whether favorable results can also be obtained when grafts are used in utero. If so, then human fetal spina bifida repair using laboratory-grown autologous fetal skin for defect closure may be envisaged.

The cell- and tissue-specific transcription mechanism of the TATA-less syntaxin 1A gene.

Syntaxin 1A (Stx1a) plays an important role in regulation of neuronal synaptic function. To clarify the mechanism of basic transcriptional regulation and neuron-specific transcription of Stx1a we cloned the Stx1a gene from rat, in which knowledge of the expression profile was accumulated, and elucidated that Stx1a consisting of 10 exons, possesses multiple transcription initiation sites and a 204-bp core promoter region (CPR) essential for transcription in PC12 cells. The TATA-less, conserved, GC-rich CPR has 2 specific protein (SP) sites that bind SP1 and are responsible for 65% of promoter activity. The endogenous CPR, including 23 CpG sites, is not methylated in PC12 cells, which express Stx1a and fetal rat skin keratinocyte (FRSK) cells, which do not, although an exogenous methylated CPR suppresses reporter activity in both lines. Trichostatin A (TSA) and class I histone deacetylase (HDAC) inhibitors, but not 5-azacytidine, induce Stx1a in FRSK cells. Acetylated histone H3 only associates to the CPR in FRSK cells after TSA addition, whereas the high acetylated histone H3-CPR association in PC12 cells was unchanged following treatment. HDAC inhibitor induction of Stx1a was negated by mithramycin A and deletion/mutation of 2 SP sites. HDAC1, HDAC2, and HDAC8 detach from the CPR when treated with TSA in FRSK cells and are associated with the CPR in lungs, and acetylated histone H3 associates to this region in the brain. In the first study characterizing a syntaxin promoter, we show that association of SP1 and acetylated histone H3 to CPR is important for Stx1a transcription and that HDAC1, HDAC2, and HDAC8 decide cell/tissue specificity in a suppressive manner.

Dynamic Expression of Novel MiRNA Candidates and MiRNA-34 Family Members in Early- to Mid-Gestational Fetal Keratinocytes Contributes to Scarless Wound Healing by Targeting the TGF-β Pathway.

BackgroundEarly- to mid-gestational fetal mammalian skin wounds heal rapidly and without scarring. Keratinocytes (KCs) have been found to exert important effects on the regulation of fibroblasts. There may be significant differences of gestational fetal KCs at different ages. The advantages in early- to mid-gestational fetal KCs could lead to fetal scarless wound healing.MethodsKCs from six human fetal skin samples were divided into two groups: a mid-gestation group (less than 28 weeks of gestational age) and a late-gestation group (more than 28 weeks of gestational age). RNA extracted from KCs was used to prepare a library of small RNAs for next-generation sequencing (NGS). To uncover potential novel microRNA (miRNAs), the mirTools 2.0 web server was used to identify candidate novel human miRNAs from the NGS data. Other bioinformatical analyses were used to further validate the novel miRNAs. The expression levels of the miRNAs were further confirmed by real-time quantitative RT-PCR.ResultsA total of 61.59 million reads were mapped to 1,170 known human miRNAs in miRBase. Among a total of 202 potential novel miRNAs uncovered, 106 candidates have a higher probability of being novel human miRNAs. A total of 110 miRNAs, including 22 novel miRNA candidates, were significantly differently expressed between mid- and late-gestational fetal KCs. Thirty-three differentially expressed miRNAs and miR-34 family members are correlated with the transforming growth factor-β (TGF-β) pathway.ConclusionsTaken together, our results provide compelling evidence supporting the existence of 106 novel miRNAs and the dynamic expression of miRNAs that extensively targets the TGF-β pathway at different gestational ages in fetal KCs. MiRNAs showing altered expression at different gestational ages in fetal KCs may contribute to scarless wound healing in early- to mid-gestational fetal KCs, and thus may be new targets for potential scar prevention and reduction therapies.

MAGE-A expression clusters and antineoplastic treatment in head and neck cancer.

The nonsurgical treatment of head and neck squamous cell carcinoma (HNSCC) usually consists of radiation and chemotherapy. In general, the treatment efficacy of chemotherapy in head and neck cancer is limited. Apart from the placenta, testis and fetal keratinocytes, melanoma-associated antigens-A (MAGE-A) are only found in malignancies. Even though their molecular role remains unclear, several subgroups have been found to contribute to resistance to different chemotherapeutic agents. In the present study, established human squamous cell carcinoma cell lines were incubated with various concentrations of cisplatin, 5-fluorouracil, paclitaxel, docetaxel, cetuximab and panitumumab for 5, 10, 20 and 40 h. The treatment efficacy was measured dynamically by real-time cell analysis (RTCA). In addition, we determined the expression of all known MAGE-A subgroups (MAGE-A1 to MAGE-A12, excluding pseudogene MAGE-A7) by reverse transcription quantitative polymerase chain reaction. Of note, one cell line showed only a marginal expression of MAGE-A antigens, whereas another cell line showed a distinct expression of almost all the MAGE-A subgroups. The expression pattern varied in the other cell lines. MAGE-A4 was the most highly expressed of all the subgroups, and MAGE-A8 could not be detected. With the exception of MAGE-A6, -A8, -A9 and -A10, the expression levels differed significantly between the cell lines. Factor analysis suggested simplifying the MAGE-A expression level into two groups. Spearman's rank correlation revealed a significant association between MAGE-A expression and treatment efficacy for 20.8% (25/120) of the experiments. In 100% of these cases (25/25), Spearman's Rho revealed a positive correlation between clustered MAGE-A expression and poor treatment efficacy. Our data highlight the fact that higher a MAGE-A expression correlates with a poorer outcome of antineoplastic treatment. Clustered MAGE-A expression analysis may help to identify patients who are at a higher risk of antineoplastic treatment failure.