[Exploring the causality between intestinal flora and hyperplastic scars of human based on two-sample Mendelian randomization analysis]

Objective: To investigate the causality between intestinal flora and hypertrophic scars (HS) of human. Methods: This study was a study based on two-sample Mendelian randomization (TSMR) analysis. The data on intestinal flora (n=18 473) and HS (n=208 248) of human were obtained from the genome-wide association study database. Genetically variable genes at five levels (phylum, class, order, family, and genus) of known intestinal flora, i.e., single nucleotide polymorphisms (SNPs), were extracted as instrumental variables for linkage disequilibrium (LD) analysis. Human genotype-phenotype association analysis was performed using PhenoScanner V2 database to exclude SNPs unrelated to HS in intestinal flora and analyze whether the selected SNPs were weak instrumental variables. The causal relationship between intestinal flora SNPs and HS was analyzed through four methods of TSMR analysis, namely inverse variance weighted (IVW), MR-Egger regression, weighted median, and weighted mode. Scatter plots of significant results from the four aforementioned analysis methods were plotted to analyze the correlation between intestinal flora SNPs and HS. Both IVW test and MR-Egger regression test were used to assess the heterogeneity of intestinal flora SNPs, MR-Egger regression test and MR-PRESSO outlier test were used to assess the horizontal multiplicity of intestinal flora SNPs, and leave-one-out sensitivity analysis was used to determine whether HS was caused by a single SNP in the intestinal flora. Reverse TSMR analyses were performed for HS SNPs and genus Intestinimonas or genus Ruminococcus2, respectively, to detect whether there was reverse causality between them. Results: A total of 196 known intestinal flora, belonging to 9 phyla, 16 classes, 20 orders, 32 families, and 119 genera, were obtained, and multiple SNPs were obtained from each flora as instrumental variables. LD analysis showed that the SNPs of the intestinal flora were consistent with the hypothesis that genetic variation was strongly associated with exposure factors, except for rs1000888, rs12566247, and rs994794. Human genotype-phenotype association analysis showed that none of the selected SNPs after LD analysis was excluded and there were no weak instrumental variables. IVW, MR-Egger regression, weighted median, and weighted mode of TSMR analysis showed that both genus Intestinimonas and genus Ruminococcus2 were causally associated with HS. Among them, forest plots of IVW and MR-Egger regression analyses also showed that 16 SNPs (the same SNPs number of this genus below) of genus Intestinimonas and 15 SNPs (the same SNPs number of this genus below) of genus Ruminococcus2 were protective factors for HS. Further, IVW analysis showed that genus Intestinimonas SNPs (with odds ratio of 0.62, 95% confidence interval of 0.41-0.93, P<0.05) and genus Ruminococcus2 SNPs (with odds ratio of 0.62, 95% confidence interval of 0.40-0.97, P<0.05) were negatively correlated with the risk of HS. Scatter plots showed that SNPs of genus Intestinimonas and genus Ruminococcus2 were protective factors of HS. Both IVW test and MR-Egger regression test showed that SNPs of genus Intestinimonas (with Q values of 5.73 and 5.76, respectively, P>0.05) and genus Ruminococcus2 (with Q values of 13.67 and 15.61, respectively, P>0.05) were not heterogeneous. MR-Egger regression test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (with intercepts of 0.01 and 0.06, respectively, P>0.05); MR-PRESSO outlier test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (P>0.05). Leave-one-out sensitivity analysis showed that no single intestinal flora SNP drove the occurrence of HS. Reverse TSMR analysis showed no reverse causality between HS SNPs and genus Intestinimonas or genus Ruminococcus2 (with odds ratios of 1.01 and 0.99, respectively, 95% confidence intervals of 0.97-1.06 and 0.96-1.04, respectively, P>0.05). Conclusions: There is a causal relationship between intestinal flora and HS of human, in which genus Intestinimonas and genus Ruminococcus2 have a certain effect on inhibiting HS.

Dysfunctional latent transforming growth factor β activation after corneal injury in a classical Ehlers-Danlos model

Patients with classical Ehlers Danlos syndrome (cEDS) suffer impaired wound healing and from scars formed after injuries that are atrophic and difficult to close surgically. Haploinsufficiency in COL5A1 creates systemic morphological and functional alterations in the entire body. We investigated mechanisms that impair wound healing from corneal lacerations (full thickness injuries) in a mouse model of cEDS (Col5a1+/-). We found that collagen V reexpression in this model is upregulated during corneal tissue repair and that wound healing is delayed, impaired, and results in large atrophic corneal scars. We noted that in a matrix with a 50 % content of collagen V, activation of latent Transforming Growth Factor (TGF) β is dysregulated. Corneal myofibroblasts with a haploinsufficiency of collagen V failed to mechanically activate latent TGF β. Second harmonic imaging microscopy showed a disorganized, undulated, and denser collagen matrix in our Col5a1+/- model that suggested alterations in the extracellular matrix structure and function. We hypothesize that a regenerated collagen matrix with only 50 % content of collagen V is not resistant enough mechanically to allow adequate activation of latent TGF β by fibroblasts and myofibroblasts.

Decoding fibrosis in the human central nervous system

Recent advancements in human tissue analyses and animal models have revealed that fibrotic scarring is a common response to various lesions in the central nervous system (CNS). Perivascular cells within the brain or spinal cord give rise to stromal fibroblasts that form fibrotic scar tissue. In this review, we summarize the current understanding of fibrotic scar formation in different CNS lesions and evaluate published human single-cell gene expression datasets to gather information on perivascular cells. Specifically, we highlight the classification of pericytes and fibroblast subtypes and compare the marker expression of perivascular cells across different datasets.

MiR-29b Downregulation by p53/Sp1 Complex Plays a Critical Role in Bleb Scar Formation After Glaucoma Filtration Surgery

Purpose

To investigate the function and mechanism of tumor protein p53 in pathological scarring after glaucoma filtration surgery (GFS) using human Tenon's fibroblasts (HTFs) and a rabbit GFS model.

Methods

The expression of p53 in bleb scarring after GFS and transforming growth factor-β (TGF-β)-induced HTFs (myofibroblasts [MFs]) was examined by western blot and immunochemical analysis. The interaction between p53 and specificity protein 1 (Sp1) was investigated by immunoprecipitation. The role of p53 and Sp1 in the accumulation of collagen type I alpha 1 chain (COL1A1) and the migration of MFs was evaluated by western blot, quantitative real-time polymerase chain reaction (qRT-PCR), wound healing, and Transwell assay. The regulatory mechanisms among p53/Sp1 and miR-29b were detected via qRT-PCR, western blot, luciferase reporter assay, and chromatin immunoprecipitation assay. The therapeutic effect of mithramycin A, a specific inhibitor of Sp1, on scarring formation was evaluated in a rabbit GFS model.

Results

p53 was upregulated in bleb scar tissue and MFs. p53 and Sp1 form a transcription factor complex that induces the accumulation of COL1A1 and promotes the migration of MFs through downregulation of miR-29b, a known suppressor of COL1A1. The p53/Sp1 axis inhibits miR-29b expression by the direct binding promoter of the miR-29b gene. Mithramycin A treatment attenuated bleb scar formation in vivo.

Conclusions

The p53/Sp1/miR-29b signaling pathway plays a critical role in bleb scar formation after GFS. This pathway could be targeted for therapeutic intervention of pathological scarring after GFS.

Translational Relevance

Our research indicates that inhibition of p53/Sp1/miR-29b is a promising therapeutic strategy for preventing post-GFS pathological scarring.

Value of genotyping and scar-phenotyping for VT ablation procedures in patients with nonischemic left ventricular cardiomyopathies

INTRODUCTION

Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE-CMR) imaging which may impact ventricular tachycardia (VT) management.

METHODS

The objective was to compare the findings of cardiomyopathy genetic testing on DE-CMR imaging and long-term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0-3 mm, 3-5 mm and >5 mm projected on the closest endocardial surface) was determined.

RESULTS

Forty-three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring-like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p = .001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p = .005), and increased VT recurrence (HR 5.7 95% CI[1.8-18.4], p = .003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22-18.0], p = .02).

CONCLUSIONS

Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation.

Interaction between Cervical Microbiota and Host Gene Regulation in Caesarean Section Scar Diverticulum

Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. However, the pathogenesis of CSD remains unexplored. In this study, we characterized the cervical microbiota, metabolome, and endometrial transcriptome of women with CSD. Based on the 16s rRNA results of cervical microbes, the microbial diversity in the CSD group was higher than that in the control group. Lactobacillus were significantly decreased in the CSD group and were mutually exclusive with potentially harmful species (Sphingomonas, Sediminbacterium, and Ralstonia) abnormally elevated in CSD. The microbiota in the CSD group exhibited low activity in carbohydrate metabolism and high activity in fatty acid metabolism, as confirmed by the metabolomic data. The metabolomic characterization identified 6,130 metabolites, of which 34 were significantly different between the two groups. In the CSD group, N-(3-hydroxy-eicosanoid)-homoserine lactone and Ternatin were significantly increased, in addition to the marked decrease in fatty acids due to high consumption. N-(3-hydroxy-eicosanoyl)-homoserine lactone is a regulator that promotes abnormal apoptosis in a variety of cells, including epithelial cells and vascular endothelial cells. This abnormal apoptosis of endometrial epithelial cells and neovascularization was also reflected in the transcriptome of the endometrium surrounding the CSD. In the endometrial transcriptome data, the upregulated genes in the CSD group were active in negatively regulating the proliferation of blood vessel endothelial cells, endothelial cells, and epithelial cells. This alteration in the host's endometrium is most likely influenced by the abnormal microbiota, which appears to be confirmed in the results by integrating host transcriptome and microbiome data. For the first time, this study described the abnormal activity characteristics of microbiota and the mechanism of host-microbiota interaction in CSD. IMPORTANCE Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. In this study, we revealed that potentially harmful microbes do have adverse effects on the host endometrium. The mechanism of these adverse effects includes the inhibition of the activity of beneficial bacteria such as lactobacilli, consumption of protective metabolites of the endometrium, and also the production of harmful metabolites. In the present study, we elucidated the mechanism from the perspectives of microbial, metabolic, and host responses, providing an important rationale to design preventive and therapeutic strategies for CSD.

The emerging therapeutic targets for scar management: genetic and epigenetic landscapes

Background

Wound healing is a complex process including hemostasis, inflammation, proliferation, and remodeling during which an orchestrated array of biological and molecular events occurs to promote skin regeneration. Abnormalities in each step of the wound healing process lead to reparative rather than regenerative responses, thereby driving the formation of cutaneous scar. Patients suffering from scars represent serious health problems such as contractures, functional and esthetic concerns as well as painful, thick, and itchy complications, which generally decrease the quality of life and impose high medical costs. Therefore, therapies reducing cutaneous scarring are necessary to improve patients' rehabilitation.

Summary

Current approaches to remove scars, including surgical and nonsurgical methods, are not efficient enough, which is in principle due to our limited knowledge about underlying mechanisms of pathological as well as the physiological wound healing process. Thus, therapeutic interventions focused on basic science including genetic and epigenetic knowledge are recently taken into consideration as promising approaches for scar management since they have the potential to provide targeted therapies and improve the conventional treatments as well as present opportunities for combination therapy. In this review, we highlight the recent advances in skin regenerative medicine through genetic and epigenetic approaches to achieve novel insights for the development of safe, efficient, and reproducible therapies and discuss promising approaches for scar management.

Key Message

Genetic and epigenetic regulatory switches are promising targets for scar management, provided the associated challenges are to be addressed.

Therapeutic downregulation of neuronal PAS domain 2 (Npas2) promotes surgical skin wound healing

Attempts to minimize scarring remain among the most difficult challenges facing surgeons, despite the use of optimal wound closure techniques. Previously, we reported improved healing of dermal excisional wounds in circadian clock neuronal PAS domain 2 (Npas2)-null mice. In this study, we performed high-throughput drug screening to identify a compound that downregulates Npas2 activity. The hit compound (Dwn1) suppressed circadian Npas2 expression, increased murine dermal fibroblast cell migration, and decreased collagen synthesis in vitro. Based on the in vitro results, Dwn1 was topically applied to iatrogenic full-thickness dorsal cutaneous wounds in a murine model. The Dwn1-treated dermal wounds healed faster with favorable mechanical strength and developed less granulation tissue than the controls. The expression of type I collagen, Tgfβ1, and α-smooth muscle actin was significantly decreased in Dwn1-treated wounds, suggesting that hypertrophic scarring and myofibroblast differentiation are attenuated by Dwn1 treatment. NPAS2 may represent an important target for therapeutic approaches to optimal surgical wound management.

ADAM15 is required for optimal collagen cross-linking and scar formation following myocardial infarction

Collagen cross-linking is an important step in optimal scar formation. Myocardial infarction (MI) results in loss of cardiomyocytes that are replaced with a scar (infarct) tissue. Disintegrin and metalloproteinases (ADAMs) are membrane-bound proteases that can interact with molecules intra- and extra-cellularly to mediate various cellular functions. ADAM15 is expressed in the myocardium, however its function in heart disease has been poorly explored. We utilized mice lacking ADAM15 (Adam15^-/-) and wildtype (WT) mice. MI, induced by ligation of the left anterior descending artery, resulted in a transient but significant rise in ADAM15 protein in the WT myocardium at 3-days. Following MI, Adam15^-/- mice exhibited markedly higher rate of left ventricular (LV) rupture compared to WT mice (66% vs. 15%, p<0.05). Echocardiography and strain analyses showed worsened LV dysfunction in Adam15^-/- mice at 3days, prior to the onset of LV rupture. Second harmonic generation imaging revealed significant disarray and reduction in fibrillar collagen density in Adam15^-/- compared to WT hearts. This was associated with lower insoluble and higher soluble collagen fractions, reduced cross-linking enzyme, lysyl oxidase-1 (LOX-1), and fibronectin which is required for LOX-1 function, in Adam15^-/--MI hearts. Post-MI myocardial inflammation was comparable between the genotypes. In vitro, primary adult cardiac fibroblasts from Adam15^-/- mice showed suppressed activation in response to ischemia (hypoxia+nutrient depletion) compared to WT fibroblasts. Adam15-deficiency was associated with reduced PAK1(p21-activated kinase-1) levels, a regulator of fibronectin and LOX-1 expression. In female mice, the rate of post-MI LV rupture, PAK1 signaling, LOX-1 and fibronectin protein levels were comparable between Adam15^-/- and WT, indicating lack of sex-dependent effects of ADAM15 post- MI. This study reports a novel function for ADAM15 in collagen cross-linking and optimal scar formation post-MI which may also apply to scar formation in other tissues.

Positive-charge tuned gelatin hydrogel-siSPARC injectable for siRNA anti-scarring therapy in post glaucoma filtration surgery

Small interfering RNA (siRNA) therapy is a promising epigenetic silencing strategy. However, its widespread adoption has been severely impeded by its ineffective delivery into the cellular environment. Here, a biocompatible injectable gelatin-based hydrogel with positive-charge tuned surface charge is presented as an effective platform for siRNA protection and delivery. We demonstrate a two-step synthesis of a gelatin-tyramine (Gtn-Tyr) hydrogel with simultaneous charge tunability and crosslinking ability. We discuss how different physiochemical properties of the hydrogel interact with siSPARC (siRNA for secreted protein, acidic and rich in cysteine), and study the positive-charge tuned gelatin hydrogel as an effective delivery platform for siSPARC in anti-fibrotic treatment. Through in vitro studies using mouse tenon fibroblasts, the positive-charge tuned Gtn-Tyr hydrogel shows sustained siSPARC cellular internalization and effective SPARC silencing with excellent biocompatibility. Similarly, the same hydrogel platform delivering siSPARC in an in vivo assessment employing a rabbit model shows an effective reduction in subconjunctival scarring in post glaucoma filtration surgery, and is non-cytotoxic compared to a commonly used anti-scarring agent, mitomycin-C. Overall, the current siRNA delivery strategy involving the positive-charge tuned gelatin hydrogel shows effective delivery of gene silencing siSPARC for anti-fibrotic treatment. The current charge tunable hydrogel delivery system is simple to fabricate and highly scalable. We believe this delivery platform has strong translational potential for effective siRNA delivery and epigenetic silencing therapy.

Topical Application of Virus-Derived Immunomodulating Proteins and Peptides to Promote Wound Healing in Mouse Models

Immune modulators play critical roles in the progression of wounds to normal or conversely delayed healing, through the regulation of normal tissue regrowth, scarring, inflammation, and growth factor expression. Many immune modulator recombinants are under active preclinical study or in clinical trial to promote improved acute or chronic wound healing and to reduce scarring. Viruses have evolved highly efficient immune modulators for the evasion of host-defensive immune responses that target and kill invasive viruses. Recent studies have proven that some of these virus-derived immune modulators can be used to promote wound healing with significantly improved speed and reduced scarring in rodent models. Mouse full-thickness excisional wound model is one of the most commonly used animal models used to study wound healing for its similarity to humans in the healing phases and associated cellular and molecular mechanisms. This chapter introduces this mouse dermal wound healing model in detail for application in studying viral immune modulators as new treatments to promote wound healing. Details of hydrogel, protein construction, and topical application methods for these therapeutic proteins are provided in this chapter.

Single-cell transcriptomic analysis of small and large wounds reveals the distinct spatial organization of regenerative fibroblasts

Wound-induced hair follicle neogenesis (WIHN) has been an important model to study hair follicle regeneration during wound repair. However, the cellular and molecular components of the dermis that make large wounds more regenerative are not fully understood. Here, we compare and contrast recently published scRNA-seq data of small scarring wounds to wounds that regenerate in hope to elucidate the role of fibroblasts lineages in WIHN. Our analysis revealed an over-representation of the newly identified upper wound fibroblasts in regenerative wound conditions, which express the retinoic acid binding protein Crabp1. This regenerative cell type shares a similar gene signature to the murine papillary fibroblast lineage, which are necessary to support hair follicle morphogenesis and homeostasis. RNA velocity analysis comparing scarring and regenerating wounds revealed the divergent trajectories towards upper and lower wound fibroblasts and that the upper populations were closely associated with the specialized dermal papilla. We also provide analyses and explanation reconciling the inconsistency between the histological lineage tracing and the scRNA-seq data from recent reports investigating large wounds. Finally, we performed a computational test to map the spatial location of upper wound fibroblasts in large wounds which revealed that upper peripheral fibroblasts might harbour equivalent regenerative competence as those in the centre. Overall, our scRNA-seq reanalysis combining multiple samples suggests that upper wound fibroblasts are required for hair follicle regeneration and that papillary fibroblasts may migrate from the wound periphery to the centre during wound re-epithelialization. Moreover, data from this publication are made available on our searchable web resource: https://skinregeneration.org/.

Pluripotent epigenetic regulator OBP-801 maintains filtering blebs in glaucoma filtration surgery model

Inhibition of fibrosis is indispensable for maintaining filtering blebs after glaucoma filtration surgery (GFS). The purpose of this study was to investigate the ability of a pluripotent epigenetic regulator OBP-801 (OBP) to ameliorate extracellular matrix formation in a rabbit model of GFS. Rabbits that underwent GFS were treated with OBP. The gene expression profiles and intraocular pressure (IOP) were monitored until 30 postoperative days. The bleb tissues were evaluated for tissue fibrosis at 30 postoperative days. In in vitro models, OBP interfered the functions of diverse genes during the wound-healing process. In in vivo GFS models, the expressions of TGF-β3, MMP-2, TIMP-2 and 3, LOX, COL1A and SERPINH1 were significantly inhibited at 30 postoperative days in the OBP group compared with those in the vehicle control group. OBP treatment involving subconjunctival injection or eye drops showed no adverse effects, and reduced levels of α-SMA and collagen deposition at the surgical wound site. OBP maintained the long-lived bleb without scar formation, and IOP was lower at 30 postoperative days compared with the vehicle control group. These findings suggest that OBP is an effective and useful candidate low-molecular-weight agent for improving wound healing and surgical outcomes in a rabbit model of GFS.

Uterine Scarring Leads to Adverse Pregnant Consequences by Impairing the Endometrium Response to Steroids

Uterine surgical scarring is an increasing risk factor for adverse pregnant consequences that threaten fetal-maternal health. The detailed molecular features of scar implantation remain largely unknown. We aim to study the pathologic features of uterine surgical scarring and the mechanisms of compromised pregnancy outcomes of scar implantation. We generated a mouse model of uterine surgical scarring with a uterine incision penetrating the myometrium to endometrium to examine the pathologic changes and transcriptome profiles of uterine scarring at various postsurgery (PS) time points, as well as features of the feto-maternal interface during scar implantation. We found that uterine surgical scar recovery was consistently poor at PS3 until PS90, as shown by a reduced number of endometrial glands, inhibition of myometrial smooth muscle cell growth but excessive collagen fiber deposition, and massive leukocyte infiltration. Transcriptome annotation indicated significant chronic inflammation at the scarring site. At the peri-implantation and postimplantation stages, abnormal expression of various steroid-responsive genes at the scarring site was in parallel with lumen epithelial cell hyperplasia, inappropriate luminal closure, and disorientation of the implanted embryo, restricted stromal cell proliferation, and defective decidualization. High embryonic lethality (around 70%) before E10.5 was observed, and the small amount of survival embryos at E10.5 exhibited restricted growth and aberrant placenta defects including overinvasion of trophoblast cells into the decidua and insufficient fetal blood vessel branching in the labyrinth. The findings indicate that chronic inflammation and compromised responses to steroids in uterine scar tissues are the pivotal molecular basis for adverse pregnancy consequences of scar implantation.

Type V Collagen in Scar Tissue Regulates the Size of Scar after Heart Injury

Scar tissue size following myocardial infarction is an independent predictor of cardiovascular outcomes, yet little is known about factors regulating scar size. We demonstrate that collagen V, a minor constituent of heart scars, regulates the size of heart scars after ischemic injury. Depletion of collagen V led to a paradoxical increase in post-infarction scar size with worsening of heart function. A systems genetics approach across 100 in-bred strains of mice demonstrated that collagen V is a critical driver of postinjury heart function. We show that collagen V deficiency alters the mechanical properties of scar tissue, and altered reciprocal feedback between matrix and cells induces expression of mechanosensitive integrins that drive fibroblast activation and increase scar size. Cilengitide, an inhibitor of specific integrins, rescues the phenotype of increased post-injury scarring in collagen-V-deficient mice. These observations demonstrate that collagen V regulates scar size in an integrin-dependent manner.

Cell Sheets from Adipose Tissue MSC Induce Healing of Pressure Ulcer and Prevent Fibrosis via Trigger Effects on Granulation Tissue Growth and Vascularization

We report a comparative study of multipotent mesenchymal stromal cells (MSC) delivered by injection, MSC-based cell sheets (CS) or MSC secretome to induce healing of cutaneous pressure ulcer in C57Bl/6 mice. We found that transplantation of CS from adipose-derived MSC resulted in reduction of fibrosis and recovery of skin structure with its appendages (hair and cutaneous glands). Despite short retention of CS on ulcer surface (3-7 days) it induced profound changes in granulation tissue (GT) structure, increasing its thickness and altering vascularization pattern with reduced blood vessel density and increased maturation of blood vessels. Comparable effects on GT vascularization were induced by MSC secretome, yet this treatment has failed to induce repair of skin with its appendages we observed in the CS group. Study of secretome components produced by MSC in monolayer or sheets revealed that CS produce more factors involved in pericyte chemotaxis and blood vessel maturation (PDGF-BB, HGF, G-CSF) but not sprouting inducer (VEGF165). Analysis of transcriptome using RNA sequencing and Gene Ontology mapping found in CS upregulation of proteins responsible for collagen binding and GT maturation as well as fatty acid metabolism enzymes known to be negative regulators of blood vessel sprouting. At the same time, downregulated transcripts were enriched by factors activating capillary growth, suggesting that in MSC sheets paracrine activity may shift towards matrix remodeling and maturation of vasculature, but not activation of blood vessel sprouting. We proposed a putative paracrine trigger mechanism potentially rendering an impact on GT vascularization and remodeling. Our results suggest that within sheets, MSC may change their functional state and spectrum of soluble factors that influence tissue repair and induce more effective skin healing inclining towards regeneration and reduced scarring.

Novel Biomedical Functions of Surfactin A from Bacillus subtilis in Wound Healing Promotion and Scar Inhibition

Surfactin produced by Bacillus subtilis is a powerful biosurfactant in food, cosmetics, and pesticide industries. However, its suitability in wound healing applications is uncertain. In this article, we determined the effects of surfactin A from B. subtilis on wound healing, angiogenesis, cell migration, inflammatory response, and scar formation. The results indicated that 80.65 ± 2.03% of surfactin A-treated wounds were closed, whereas 44.30 ± 4.26% of the vehicle-treated wound areas remained open on day 7 (P < 0.05). In mechanisms, it upregulated the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF), accelerated keratinocyte migration through mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways, and regulated the secretion of proinflammatory cytokines and macrophage phenotypic switch. More attractive, surfactin A showed a seductive capability to inhibit scar tissue formation by affecting the expression of α-smooth muscle actin (α-SMA) and transforming growth factor (TGF-β). Overall, the study revealed a new function and potential of surfactin A as an affordable and efficient wound healing drug.

Expression of Metalloproteinases and Type I and III Collagens during Healing of Excisional Skin Wound on the Abdomen and Back in Rats

The study was carried out using a novel rat model developed in our laboratory, namely16 mm diameter circular excisional wounds were generated on the abdomen which resulted in minimal scarring. Restoration of the skin integrity was completed by day 60 after the wounding surgery. By this time, regenerates on the abdomen were stronger than on the back (at, respectively, 58 and 17.4 % of the tensile strength of the intact skin at corresponding location) and the ratio of type I and type III collagens in regenerates on the abdomen reached the level of intact skin at the same location. On days 3 to 14, the ratio of Mmp9/Timp1 expression levels on the abdomen was higher than on the back. On days 20 and 30, the Mmp9/Timp1 ratio on the abdomen was identical to the level of intact skin, whereas the increased MMPs expression levels on the back were maintained until day 30. It has been shown for the first time that according to functional and molecular characteristics, wound healing on the abdomen of an adult rat is more similar to complete regeneration than scarring repair of the back skin.

Embryonic mesothelial-derived hepatic lineage of quiescent and heterogenous scar-orchestrating cells defined but suppressed by WT1

Activated hepatic stellate cells (aHSCs) orchestrate scarring during liver injury, with putative quiescent precursor mesodermal derivation. Here we use lineage-tracing from development, through adult homoeostasis, to fibrosis, to define morphologically and transcriptionally discreet subpopulations of aHSCs by expression of WT1, a transcription factor controlling morphological transitions in organogenesis and adult homoeostasis. Two distinct populations of aHSCs express WT1 after injury, and both re-engage a transcriptional signature reflecting embryonic mesothelial origin of their discreet quiescent adult precursor. WT1-deletion enhances fibrogenesis after injury, through upregulated Wnt-signalling and modulation of genes central to matrix persistence in aHSCs, and augmentation of myofibroblastic transition. The mesothelial-derived lineage demonstrates punctuated phenotypic plasticity through bidirectional mesothelial-mesenchymal transitions. Our findings demonstrate functional heterogeneity of adult scar-orchestrating cells that can be whole-life traced back through specific quiescent adult precursors to differential origin in development, and define WT1 as a paradoxical regulator of aHSCs induced by injury but suppressing scarring.

A case of Ehlers-Danlos syndrome presenting with widened atrophic scars of forehead, elbow, knee, and pretibial area: A case report

RATIONAL

Ehlers-Danlos syndrome (EDS) is a heritable connective tissue disorder. Currently, the genotype-phenotype correlations of classical EDS (cEDS) are still controversial. Hence, this study reported a case of cEDS with both clinical manifestations and COL5A2 gene mutation.

PATIENT CONCERNS

A 30-year-old female presented to the plastic-surgery clinic with widen atrophic scars on forehead, elbows, knees and pretibial area that had developed since childhood.

DIAGNOSIS

With the skin hyperextensibility, joint hypermobility, papyraceous scar revealed by physical examination, and the heterozygous pathogenic variant c1997G > A (p.P659P) in COL5A2 gene revealed by whole exome sequencing, the diagnosis of the classical Ehlers-Danlos syndrome was made.

INTERVENTIONS

The patient underwent facial scar resection and sutured in minimizing tension and perfect apposition to avoid the post-surgery scar formation.

OUTCOMES

Follow-up 6 months after surgery, the wound remained a fine line scar.

LESSONS

Our findings suggested that COL5A2 gene mutation (c1997G > A p.P659P) may be associated with cEDS but did not reveal other severe complications.

Mechanisms of Scarring in Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) presents with scar in parts of some glomeruli and often progresses to global and diffuse glomerulosclerosis. Podocyte injury is the initial target in primary FSGS, induced by a circulating factor. Several gene variants, for example, APOL1, are associated with increased susceptibility to FSGS. Primary FSGS may be due to genetic mutation in key podocyte genes. Increased work stress after loss of nephrons, epigenetic mechanisms, and various profibrotic pathways can contribute to progressive sclerosis, regardless of the initial injury. The progression of FSGS lesions also involves crosstalk between podocytes and other kidney cells, such as parietal epithelial cells, glomerular endothelial cells, and even tubular epithelial cells. New insights related to these mechanisms could potentially lead to new therapeutic strategies to prevent progression of FSGS.

Sphingosine-1-Phosphate Facilitates Skin Wound Healing by Increasing Angiogenesis and Inflammatory Cell Recruitment with Less Scar Formation

Wound healing starts with the recruitment of inflammatory cells that secrete wound-related factors. This step is followed by fibroblast activation and tissue construction. Sphingosine-1-phosphate (S1P) is a lipid mediator that promotes angiogenesis, cell proliferation, and attracts immune cells. We investigated the roles of S1P in skin wound healing by altering the expression of its biogenic enzyme, sphingosine kinase-1 (SphK1). The murine excisional wound splinting model was used. Sphingosine kinase-1 (SphK1) was highly expressed in murine wounds and that SphK1^−/− mice exhibit delayed wound closure along with less angiogenesis and inflammatory cell recruitment. Nanoparticle-mediated topical SphK1 overexpression accelerated wound closure, which associated with increased angiogenesis, inflammatory cell recruitment, and various wound-related factors. The SphK1 overexpression also led to less scarring, and the interaction between transforming growth factor (TGF)-β1 and S1P receptor-2 (S1PR2) signaling is likely to play a key role. In summary, SphK1 play important roles to strengthen immunity, and contributes early wound healing with suppressed scarring. S1P can be a novel therapeutic molecule with anti-scarring effect in surgical, trauma, and chronic wound management.

Implications of scar structure and mechanics for post-infarction cardiac repair and regeneration

Regenerating cardiac muscle lost during a heart attack is a topic of broad interest and enormous potential impact. One promising approach is to regenerate or re-engineer new myocardium in situ, at the site of damage, by injecting cells, growth factors, and other materials, or by reprogramming aspects of the normal wound healing process. A wide variety of strategies have been explored, from promoting angiogenesis to injection of a variety of different progenitor cell types, to re-engineering resident cells to produce key growth factors or even transdifferentiate into myocytes. Despite substantial progress and continued promise, clinical impact of this work has fallen short of expectations. One contributing factor may be that many efforts focus primarily on generating cardiomyocytes, with less attention to re-engineering the extracellular matrix (ECM). Yet the role of the ECM is particularly crucial to consider following myocardial infarction, which leads to rapid formation of a collagen-rich scar. This review combines a brief summary of current efforts to regenerate cardiomyocytes with what is currently known about the structure and mechanics of post-infarction scar, with the goal of identifying principles that can guide efforts to produce new myocytes embedded in an extracellular environment that facilitates their differentiation, maintenance, and function.

Variant PADI3 in Central Centrifugal Cicatricial Alopecia

BACKGROUND

Central centrifugal cicatricial alopecia (CCCA) is the most common form of scarring alopecia among women of African ancestry. The disease is occasionally observed to affect women in families in a manner that suggests an autosomal dominant trait and usually manifests clinically after intense hair grooming. We sought to determine whether there exists a genetic basis of CCCA and, if so, what it is.

METHODS

We used exome sequencing in a group of women with alopecia (discovery set), compared the results with those in a public repository, and applied other filtering criteria to identify candidate genes. We then performed direct sequencing to identify disease-associated DNA variations and RNA sequencing, protein modeling, immunofluorescence staining, immunoblotting, and an enzymatic assay to evaluate the consequences of potential etiologic mutations. We used a replication set that consisted of women with CCCA to confirm the data obtained with the discovery set.

RESULTS

In the discovery set, which included 16 patients, we identified one splice site and three heterozygous missense mutations in PADI3 in 5 patients (31%). (The approximate prevalence of the disease is up to 5.6%.) PADI3 encodes peptidyl arginine deiminase, type III (PADI3), an enzyme that post-translationally modifies other proteins that are essential to hair-shaft formation. All three CCCA-associated missense mutations in PADI3 affect highly conserved residues and are predicted to be pathogenic; protein modeling suggests that they result in protein misfolding. These mutations were found to result in reduced PADI3 expression, abnormal intracellular localization of the protein, and decreased enzymatic activity - findings that support their pathogenicity. Immunofluorescence staining showed decreased expression of PADI3 in biopsy samples of scalp skin obtained from patients with CCCA. We then directly sequenced PADI3 in an additional 42 patients (replication set) and observed genetic variants in 9 of them. A post hoc analysis of the combined data sets showed that the prevalence of PADI3 mutation was higher among patients with CCCA than in a control cohort of women of African ancestry (P = 0.002 by the chi-square test; P = 0.006 by Fisher's exact test; and after adjustment for relatedness of persons, P = 0.03 and P = 0.04, respectively).

CONCLUSIONS

Mutations in PADI3, which encodes a protein that is essential to proper hair-shaft formation, were associated with CCCA. (Funded by the Ram Family Foundation and others.).

Compensatory regrowth of the mouse bladder after partial cystectomy

Cystectomy is the removal of all or part of the urinary bladder. It has been observed that there is significant regrowth of the bladder after partial cystectomy and this has been proposed to be through regeneration of the organ. Regrowth of tissue in mammals has been proposed to involve compensatory mechanisms that share many characteristics of true regeneration, like the growth of specialized structures such as blood vessels or nerves. However, the overall structure of the normal organ is not achieved. Here we tested if bladder growth after subtotal cystectomy (STC, removal of 50% of the bladder) was compensatory or regenerative. To do this we subjected adult female mouse bladders to STC and assessed regrowth using several established cellular parameters including histological, gene expression, cytokine accumulation and cell proliferation studies. Bladder function was analyzed using cystometry and the voiding stain on paper (VSOP) technique. We found that STC bladders were able to increase their ability to hold urine with the majority of volume restoration occurring within the first two weeks. Regenerating bladders had thinner walls with less mean muscle thickness, and they showed increased collagen deposition at the incision as well as throughout the bladder wall suggesting that fibrosis was occurring. Cell populations differed in their response to injury with urothelial regeneration complete by day 7, but stromal and detrusor muscle still incomplete after 8wks. Cells incorporated EdU when administered at the time of surgery and tracing of EdU positive cells over time indicated that many newborn cells originate at the incision and move mediolaterally. Basal urothelial cells and bladder mesenchymal stem cells but not smooth muscle cells significantly incorporated EdU after STC. Since anti-inflammatory cytokines play a role in regeneration, we analyzed expressed cytokines and found that no anti-inflammatory cytokines were present in the bladder 1wk after STC. Our findings suggest that bladder regrowth after cystectomy is compensatory and functions to increase the volume that the bladder can hold. This finding sets the stage for understanding how the bladder responds to cystectomy and how this can be improved in patients after suffering bladder injury.

Sebaceous gland abnormalities in fatty acyl CoA reductase 2 (Far2) null mice result in primary cicatricial alopecia

In a large scale screen for skin, hair, and nail abnormalities in null mice generated by The Jackson Laboratory’s KOMP center, homozygous mutant Far2^{tm2b(KOMP)Wtsi}/2J (hereafter referrred to as Far2^-/-) mice were found to develop focal areas of alopecia as they aged. As sebocytes matured in wildtype C57BL/NJ mice they became pale with fine, uniformly sized clear lipid containing vacuoles that were released when sebocytes disintegrated in the duct. By contrast, the Far2^-/- null mice had sebocytes that were similar within the gland but become brightly eosinophilic when the cells entered the sebaceous gland duct. As sebocytes disintegrated, their contents did not readily dissipate. Scattered throughout the dermis, and often at the dermal hypodermal fat junction, were dystrophic hair follicles or ruptured follicles with a foreign body granulomatous reaction surrounding free hair shafts (trichogranuloma). The Meibomian and clitoral glands (modified sebaceous glands) of Far2^-/- mice showed ducts dilated to various degrees that were associated with mild changes in the sebocytes as seen in the truncal skin. Skin surface lipidomic analysis revealed a lower level of wax esters, cholesterol esters, ceramides, and diacylglycerols compared to wildtype control mice. Similar changes were described in a number of other mouse mutations that affected the sebaceous glands resulting in primary cicatricial alopecia.

Immunofibrogenic Gene Expression Patterns in Tanzanian Children with Ocular Chlamydia trachomatis Infection, Active Trachoma and Scarring: Baseline Results of a 4-Year Longitudinal Study

Trachoma, caused by Chlamydia trachomatis, is the world's leading infectious cause of blindness and remains a significant public health problem. Much of trachomatous disease pathology is thought to be caused indirectly by host cellular and immune responses, however the immune response during active trachoma and how this initiates progressive scarring is not clearly understood. Defining protective vs. pathogenic immune response to C. trachomatis is important for vaccine design and evaluation. This study reports the baseline results of a longitudinal cohort of Tanzanian children, who were monitored for 4 years in order to determine the immunofibrogenic and infectious correlates of progressive scarring trachoma. In this cohort baseline, 506 children aged 6-10 years were assessed for clinical signs, infection status and the expression of 91 genes of interest prior to mass azithromycin administration for trachoma control. C. trachomatis was detected using droplet digital PCR and gene expression was measured using quantitative real-time PCR. The prevalence of follicles, papillary inflammation and scarring were 33.6, 31.6, and 28.5%, respectively. C. trachomatis was detected in 78/506 (15.4%) individuals, 62/78 of whom also had follicles. C. trachomatis infection was associated with a strong upregulation of IFNG and IL22, the enrichment of Th1 and NK cell pathways and Th17 cell-associated cytokines. In individuals with inflammation in the absence of infection the IFNG/IL22 and NK cell response was reduced, however, pro-inflammatory, growth and matrix factors remained upregulated and mucins were downregulated. Our data suggest that, strong IFNG/IL22 responses, probably related to Th1 and NK cell involvement, is important for clearance of C. trachomatis and that the residual pro-inflammatory and pro-fibrotic phenotype that persists after infection might contribute to pathological scarring. Interestingly, females appear more susceptible to developing papillary inflammation and scarring than males, even at this young age, despite comparable levels of C. trachomatis infection. Females also had increased expression of a number of IFNγ pathway related genes relative to males, suggesting that overexpression of this pathway in response to infection might contribute to more severe scarring. Longitudinal investigation of these factors will reveal their relative contributions to protection from C. trachomatis infection and development of scarring complications.

Obesity/Type II diabetes alters macrophage polarization resulting in a fibrotic tendon healing response

Type II Diabetes (T2DM) dramatically impairs the tendon healing response, resulting in decreased collagen organization and mechanics relative to non-diabetic tendons. Despite this burden, there remains a paucity of information regarding the mechanisms that govern impaired healing of diabetic tendons. Mice were placed on either a high fat diet (T2DM) or low fat diet (lean) and underwent flexor tendon transection and repair surgery. Healing was assessed via mechanical testing, histology and changes in gene expression associated with collagen synthesis, matrix remodeling, and macrophage polarization. Obese/diabetic tendons healed with increased scar formation and impaired mechanical properties. Consistent with this, prolonged and excess expression of extracellular matrix (ECM) components were observed in obese/T2DM tendons. Macrophages are involved in both inflammatory and matrix deposition processes during healing. Obese/T2DM tendons healed with increased expression of markers of pro-inflammatory M1 macrophages, and elevated and prolonged expression of M2 macrophages markers that are involved in ECM deposition. Here we demonstrate that tendons from obese/diabetic mice heal with increased scar formation and increased M2 polarization, identifying excess M2 macrophage activity and matrix synthesis as a potential mechanism of the fibrotic healing phenotype observed in T2DM tendons, and as such a potential target to improve tendon healing in T2DM.

GREM1 is expressed in the cancer-associated myofibroblasts of basal cell carcinomas

Cancer-associated fibroblasts (CAFs) play important roles in cancer progression through their complex interactions with cancer cells. The secreted bone morphogenetic protein antagonist, gremlin1 (GREM1) is expressed by the CAFs of basal cell carcinomas (BCCs), and promotes the growth of cancer cells. In this study, we investigated the expression of GREM1 mRNAs in various benign and malignant skin tumors, including various BCC subtypes. Analysis by RNA in situ hybridization (ISH) revealed that fibroblasts in the scar tissue expressed GREM1 and α-smooth muscle actin (α-SMA), whereas resident fibroblasts in the dermis of the normal skin did not express GREM1. Real-time polymerase chain reaction analysis showed significantly higher GREM1 expression in skin cancers and pilomatricomas (PMCs) than in other benign skin tumors. Tissue microarrays analyzed by RNA ISH for GREM1 expression also demonstrated that 23% of BCCs, 42% of squamous cell carcinomas, 20% of melanomas, and 90% of PMCs were positive for GREM1 expression, whereas trichoepitheliomas, eccrine poromas, hidradenomas, and spiradenomas were negative for GREM1 expression. Most BCCs that were GREM1 expression positive were of desmoplastic or mixed subtypes, and GREM1 expression was localized to activated myofibroblasts at the tumoral-stromal interface. Interestingly, most PMCs harbored GREM1-expressing fibroblasts, probably because of the inflammatory responses caused by foreign body reactions to keratin. Additionally, in BCCs, stromal GREM1 expression had a strong correlation with CD10 expression. In conclusion, GREM1 is frequently expressed by myofibroblasts in scars or in the stroma of basal cell carcinomas, suggesting that GREM1 expression can be a marker for activated myofibroblasts in the cancer stroma or in scar tissue.

Evaluation of IL-12RB1, IL-12B, CXCR-3 and IL-17a expression in cases affected by a non-healing form of cutaneous leishmaniasis: an observational study design

INTRODUCTION

Seldom cutaneous leishmaniasis (CL) may present as a lasting and active lesion(s), known as a non-healing form of CL (NHCL). Non-functional type 1 T helper (Th1) cells are assumed the most important factor in the outcome of the disease. The present study aims to assess some molecular defects that potentially contribute to Th1 impairment in NHCL.

METHODS AND ANALYSIS

This prospective observational study will be implemented among five groups. The first and second groups comprise patients afflicted with non-healing and healing forms of CL, respectively. The third group consists of those recovered participants who have scars as a result of CL. Those participants who have never lived or travelled to endemic areas of leishmaniasis will comprise the fourth group. The fifth group comprises participants living in hyperendemic areas for leishmaniasis, although none of them have been afflicted by CL. The aim is to recruit 10 NHCL cases and 30 participants in each of the other groups. A leishmanin skin test (LST) will be performed to assess in vivo immunity against the Leishmania infection. The cytokine profile (interleukin (IL)-12p70, interferon (IFN)-γ, C-X-C motif chemokine ligand (CXCL)-11 and IL-17a) of the isolated peripheral blood mononuclear cells (PBMCs) will be evaluated through ELISA. Real-time PCR will determine the C-X-C motif chemokine receptor (CXCR)-3 and IL-17a gene expression and expression of IL-12Rβ1 will be assessed by flow cytometry. Furthermore, IL-12B and IL-12RB1 mutation analysis will be performed.

DISCUSSION

It is anticipated that the outcome of the current study will identify IL-12B and IL-12RB1 mutations, which lead to persistent lesions of CL. Furthermore, our expected results will reveal an association between NHCL and pro-inflammatory cytokines (IL-12p70, IFN-γ IL-17a and CXCL-11), as well as CXCR-3 expression.

ETHICS AND DISSEMINATION

This study has been approved by a local ethical committee. The final results will be disseminated through peer-reviewed journals and scientific conferences.

Modeling fibrosis using fibroblasts isolated from scarred rat vocal folds

Following injury, pathologically activated vocal fold fibroblasts (VFFs) can engage in disordered extracellular matrix (ECM) remodeling, leading to VF fibrosis and impaired voice function. Given the importance of scar VFFs to phenotypically appropriate in vitro modeling of VF fibrosis, we pursued detailed characterization of scar VFFs obtained from surgically injured rat VF mucosae, compared with those obtained from experimentally naïve, age-matched tissue. Scar VFFs initially exhibited a myofibroblast phenotype characterized by increased proliferation, increased Col1a1 transcription and collagen, type I synthesis, increased Acta2 transcription and α-smooth muscle actin synthesis, and enhanced contractile function. These features were most distinct at passage 1 (P1); we observed a coalescence of the scar and naïve VFF phenotypes at later passages. An empirical Bayes statistical analysis of the P1 cell transcriptome identified 421 genes that were differentially expressed by scar, compared with naïve, VFFs. These genes were primarily associated with the wound response, ECM regulation, and cell proliferation. Follow-up comparison of P1 scar VFFs and their in vivo tissue source showed substantial transcriptomic differences. Finally, P1 scar VFFs responded to treatment with hepatocyte growth factor and transforming growth factor-β3, two biologics with reported therapeutic value. Despite the practical limitations inherent to working with early passage cells, this experimental model is easily implemented in any suitably equipped laboratory and has the potential to improve the applicability of preclinical VF fibrosis research.

A Tool for Multiple Targeted Genome Deletions that Is Precise, Scar-Free, and Suitable for Automation

Many advances in synthetic biology require the removal of a large number of genomic elements from a genome. Most existing deletion methods leave behind markers, and as there are a limited number of markers, such methods can only be applied a fixed number of times. Deletion methods that recycle markers generally are either imprecise (remove untargeted sequences), or leave scar sequences which can cause genome instability and rearrangements. No existing marker recycling method is automation-friendly. We have developed a novel openly available deletion tool that consists of: 1) a method for deleting genomic elements that can be repeatedly used without limit, is precise, scar-free, and suitable for automation; and 2) software to design the method’s primers. Our tool is sequence agnostic and could be used to delete large numbers of coding sequences, promoter regions, transcription factor binding sites, terminators, etc in a single genome. We have validated our tool on the deletion of non-essential open reading frames (ORFs) from S. cerevisiae. The tool is applicable to arbitrary genomes, and we provide primer sequences for the deletion of: 90% of the ORFs from the S. cerevisiae genome, 88% of the ORFs from S. pombe genome, and 85% of the ORFs from the L. lactis genome.

Crmp4 deletion promotes recovery from spinal cord injury by neuroprotection and limited scar formation

Axonal outgrowth inhibitors and scar formation are two major obstacles to central nervous system (CNS) repair. No target molecule that regulates both axonal growth and scarring has been identified. Here we identified collapsin response mediator protein 4 (CRMP4), a common mediator of inhibitory signals after neural injury, as a crucial factor that contributes to both axonal growth inhibition and scarring after spinal cord injury (SCI). We found increases in the inhibitory and toxic forms of CRMP4 in injured spinal cord. Notably, CRMP4 expression was evident in inflammatory cells as well as in neurons after spinal cord transection. Crmp4-/- mice displayed neuroprotection against SCI and reductions in inflammatory response and scar formation. This permissive environment for axonal growth due to CRMP4 deletion restored locomotor activity at an unusually early phase of healing. These results suggest that deletion of CRMP4 is a unique therapeutic strategy that overcomes two obstacles to CNS repair after SCI.

Differentially expressed miRNAs in acute wound healing of the skin: a pilot study

The aim of the present study was to compare expression of microRNAs (miRNAs) from scar and normal skin areas in patients who suffered acute injuries in the skin. A total of 9 patients with acute injuries in the skin who received surgical treatment from December 2012 to March 2013 were included in this pilot study. Specimens from the hypertrophic scar and normal skin areas were obtained from the same patient during surgery. To screen for differentially expressed miRNAs, we applied 3 statistical methods, namely the traditional t test, the false discovery rate (FDR), and a novel sure independence screening procedure based on the distance correlation (DC-SIS). We examined the functional trends and metabolic and regulatory pathways for the target genes of the identified miRNAs, and explored interaction of these miRNAs in the implication of scar healing using Ingenuity Pathway Analysis. DC-SIS identified 18 differentially expressed miRNAs, 4 of which (miR-149, miR-203a, miR-222, miR-122) were also identified by FDR. The target genes of the 4 miRNAs exhibit a variety of biological functions, and are involved in various pathways such as mitogen-activated protein kinase, Wnt signaling, and focal adhesion. We identified 1 network in which 14 out of the 18 differentially expressed miRNAs were involved. Many of the miRNAs in the network target genes were involved in cell proliferation and apoptosis.In this pilot study, we identified several miRNAs exhibiting differential expression in patients who suffered acute injuries in the skin. Further studies on these miRNAs are needed to validate our findings and explore their roles in the wound healing process of the skin.

Increased expression of three types of transient receptor potential channels (TRPA1, TRPV4 and TRPV3) in burn scars with post-burn pruritus

Post-burn pruritus is a common distressing consequence of burn wounds. Empirical treatment often fails to have a satisfactory outcome on post-burn pruritus, as the mechanism of post-burn pruritus has not been fully elucidated. The aim of this study was to evaluate the manifestation of transient receptor potential (TRP) channels in post-burn pruritus. Fifty-one burn patients with (n=33) or without (n=18) pruritus were investigated, including skin biopsies. Not unexpectedly, the scarred body area was larger in the former group. In immunohistochemistry, TPRV3 was significantly elevated in the epidermis of burn scars with pruritus. Furthermore, real time- PCR showed that mRNA of TRPA1 and TRPV4 was increased in itching burn scars. Staining for substance P and CGRP did not differ between the 2 grouped, but the former neuropeptide was increased in burn scars. These results may help determine a specific therapeutic approach for post-burn pruritus.

[Screening and bioinformatics analysis of differentially expressed genes in hyperplastic scar]

OBJECTIVE

To screen differentially expressed genes in hyperplastic scar to explore the pathogenesis of hyperplastic scar and identify new therapeutic targets.

METHODS

Three pairs of surgical specimens of hyperplastic scar and adjacent normal skin tissues were collected to investigate the differentially expressed genes in hyperplastic scar using Agilent gene oligonucletide microarray and clustering analysis. DAVID Bioinformatics Resources 6.7 was used for GO analysis and pathway analysis.

RESULTS AND CONCLUSION

Distinctly different gene expression profiles were found between hyperplastic scar tissues and normal skin tissues. Compared with normal skin tissue, hyperplastic scar tissues showed 3142 up-regulated and 2984 down-regulated genes by two folds and 28 up-regulated and 44 down-regulated genes by 5 folds after repeating the experiment once; after repeating the experiment twice, 3004 genes were found up-regulated and 3038 down-regulated by 2 folds and 25 up-regulated and 38 down-regulated by 5 folds in hyperplastic scars. In all the 3 specimens, 1920 genes were up-regulated and 1912 down-regulated by 2 folds and 18 up-regulated and 29 down-regulated by 5 folds. The dysregulated genes in hyperplastic scar were involved in cell cycles, cell proliferation, immune response and cell adhesion (CDKN1C, CDKN2A, CTNNA3, COL6A3, and HOXB4) and in signaling pathway of focal adhesion, TGF-beta signaling pathway, p53 signaling pathway, cell cycle, and tumor-associated pathways (TGFβ1, CDKN1C, CDKN2A, CDC14A , ITGB6, and EGF).

[The preliminary study of gene copy number variation association with scar hyperplasia based on the whole-gene resequencing]

OBJECTIVE

To investigate the genome copy number variation (CNV) related with keloid using the whole-gene resequencing technology.

METHODS

A keloid pedigree containing 4 generation of 27 people was studied. Five people (4 cases of keloid patients, and 1 case of normal) were selected to extract the genomic DNA. Then the whole-gene resequencing technique was used to check the variations based on the Illumina Hiseq 2000.

RESULTS

Through database comparison and variation annotation analysis, 15 CNVs associated with scar hyperplasia were obtained. DAVID software was used to do the Gene Ontology and pathway analysis. Five CNVs were closely related to the keloid formation. They were growth factor receptor-bound 7 (Grb7), mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), mitogen-activated protein kinase kinase kinase 15 (MAP3K15), kruppel-like factors 7 (KLF7) and NK2 homeobox 2 (NKX2-2). These CNVs were involved in the process of epidermal cells formation and differentiation, cell exocrine and cell adhesion.

CONCLUSIONS

There are 5 CNVs associated with scar hyperplasia. Especially MAP3K15 and MAP4K4 deserve more research to find their function in keloid formation.

Haploinsufficiency of Def activates p53-dependent TGFβ signalling and causes scar formation after partial hepatectomy

The metazoan liver exhibits a remarkable capacity to regenerate lost liver mass without leaving a scar following partial hepatectomy (PH). Whilst previous studies have identified components of several different signaling pathways that are essential for activation of hepatocyte proliferation during liver regeneration, the mechanisms that enable such regeneration to occur without accompanying scar formation remain poorly understood. Here we use the adult zebrafish liver, which can regenerate within two weeks following PH, as a new genetic model to address this important question. We focus on the role of Digestive-organ-expansion-factor (Def), a nucleolar protein which has recently been shown to complex with calpain3 (Capn3) to mediate p53 degradation specifically in the nucleolus, in liver regeneration. Firstly, we show that Def expression is up-regulated in the wild-type liver following amputation, and that the def^hi429/+ heteroozygous mutant (def^+/−) suffers from haploinsufficiency of Def in the liver. We then show that the expression of pro-inflammatory cytokines is up-regulated in the def^+/− liver, which leads to distortion of the migration and the clearance of leukocytes after PH. Transforming growth factor β (TGFβ) signalling is thus activated in the wound epidermis in def^+/− due to a prolonged inflammatory response, which leads to fibrosis at the amputation site. Fibrotic scar formation in def^+/− is blocked by the over-expression of Def, by the loss-of-function of p53, and by treatment with anti-inflammation drug dexamethasone or TGFβ-signalling inhibitor SB431542. We finally show that the Def- p53 pathway suppresses fibrotic scar formation, at least in part, through the regulation of the expression of the pro-inflammatory factor, high-mobility group box 1. We conclude that the novel Def- p53 nucleolar pathway functions specifically to prevent a scar formation at the amputation site in a normal amputated liver.

Digital imaging analysis to assess scar phenotype

In order to understand the link between the genetic background of patients and wound clinical outcomes, it is critical to have a reliable method to assess the phenotypic characteristics of healed wounds. In this study, we present a novel imaging method that provides reproducible, sensitive, and unbiased assessments of postsurgical scarring. We used this approach to investigate the possibility that genetic variants in orofacial clefting genes are associated with suboptimal healing. Red-green-blue digital images of postsurgical scars of 68 patients, following unilateral cleft lip repair, were captured using the 3dMD imaging system. Morphometric and colorimetric data of repaired regions of the philtrum and upper lip were acquired using ImageJ software, and the unaffected contralateral regions were used as patient-specific controls. Repeatability of the method was high with intraclass correlation coefficient score > 0.8. This method detected a very significant difference in all three colors, and for all patients, between the scarred and the contralateral unaffected philtrum (p ranging from 1.20(-05) to 1.95(-14) ). Physicians' clinical outcome ratings from the same images showed high interobserver variability (overall Pearson coefficient = 0.49) as well as low correlation with digital image analysis results. Finally, we identified genetic variants in TGFB3 and ARHGAP29 associated with suboptimal healing outcome.

FibromiRs: translating molecular discoveries into new anti-fibrotic drugs

Fibrosis, or tissue scarring, is defined as excessive and persistent accumulation of extracellular matrix components in response to chronic tissue injury. Fibrosis is a pathological feature characterizing nearly all forms of chronic organ failure. Fibroproliferative disorders of liver, kidney, heart, and lung are frequently associated with considerable morbidity and mortality worldwide. Limited therapeutic options are available; none is yet effective in stopping the ultimate progression of the disease. This has prompted investigations for new molecular targets. Recent studies have shown aberrant expression of miRNAs (fibromiRs) during the development of fibrosis. The challenge now is to understand how these aberrantly expressed miRNAs collaborate to drive fibrogenesis. Progress in understanding how fibromiRs contribute to tissue fibrosis is necessary to translate molecular discoveries into new therapeutics for fibroproliferative diseases.

[Relationship between gene p53 codon 72 polymorphism and pathological scar formation after caesarean section]

OBJECTIVE

To study the relationship between gene p53 codon 72 polymorphism and pathological scar formation occurrence after caesarean section.

METHODS

The method of molecular beacon with real-time PCR was applied to detect gene polymorphism of p53 codon 72 in blood samples taken from 303 pregnant women (within a week after caesarea section). The clinical visits were taken 3 times for 12th to 18th months to ascertain clinical formation of pathological scar and its relationship to genotype of p53. The chi-square method was used to analyze the relationship of p53 gene polymorphism and abnormal scar formation occurrence by statistical software SPSS 13.0.

RESULTS

Total of 303 pregnant women were assayed. 30 patients were found with pathological scar by clinical visit in the total 303 pregnant women. The genotype frequencies of total three types (C/C, C/G and G/G) of p53 gene codon 72 in patients with pathological scar are significantly different from that of normal pregnant woman. The frequency of C/C genotype in patients are higher than that of normal pregnant women (P < 0.01). The frequency of C/C genotype in these patients with pathological scar is higher (46.7%, 14/30) than C/G (33.0%, 10/30, P < 0.01) or G/G (20%, 6/30) genotype (P < 0.01). The C allele frequency in the patients is 63.7%. It is also higher than G allele (36.7%, P < 0.01). The OR value is 2.30. Therefore the C allele of p53 gene codon 72 is a risk factor for pathological scar.

CONCLUSIONS

There was a certain relationship between p53 gene codon 72 C allele and pathological scar formation after caesarean section.

[Construction and expression identification of human secreted apoptosis-related protein 1 gene yeast two-hybrid bait vector]

OBJECTIVE

To construct human secreted apoptosis-related protein 1 (SARP1) gene yeast two-hybrid bait vector so as to study the biological functions of the SARP1 gene in the scar tissue.

METHODS

The target gene from SARP1 gene full-length DNA segment was amplified by PCR, the upstream and downstream primers of the SARP1 gene with restriction enzymes Nde I and Sal I were designed. pGBKT7-SARP1 recombination plasmid was constructed by ligating the vector and the PCR production and identified by PCR and sequencing. Further more, pGBKT7-SARP1 was transformed into competent AH109 which contained kanamycin for selecting positive clones and screened the positive clony on the plate of SD/-Trp. The toxicity and transcriptional activation were tested by the phenotype assay.

RESULTS

SARP1 was amplified and cloned into pGBKT7 successfully, SARP1 gene sequence in recombinant plasmid pGBKT7-SARP1 was verified by gel electrophoresis and DNA sequencing analysis. The sequence of inserted SARP1 gene was the same as the corresponding sequence found in GenBank database. The recombinant pGBKT7-SARP1 plasmids and empty pGBKT7 vector could form white colonies on SD/-Trp plates and none could survive on SD/-Leu plates.

CONCLUSION

The recombinant pGBKT7-SARP1 gene yeast two-hybrid bait vector is successfully constructed.

Transforming growth factor Beta 3 is required for excisional wound repair in vivo

Wound healing is a complex process that relies on proper levels of cytokines and growth factors to successfully repair the tissue. Of particular interest are the members of the transforming growth factor family. There are three TGF-ß isoforms-TGF- ß 1, 2, and 3, each isoform showing a unique expression pattern, suggesting that they each play a distinct function during development and repair. Previous studies reported an exclusive role for TGF-ß 3 in orofacial development and a potent anti-scarring effect. However, the role of TGF- ß 3 in excisional wound healing and keratinocyte migration remains poorly understood. We tested the effect of TGF-ß 3 levels on excisional cutaneous wounds in the adult mouse by directly injecting recombinant TGF-ß 3 or neutralizing antibody against TGF-ß 3 (NAB) in the wounds. Our results demonstrate that TGF-ß 3 does not promote epithelialization. However, TGF-ß 3 is necessary for wound closure as wounds injected with neutralizing antibody against TGF-ß 3 showed increased epidermal volume and proliferation in conjunction with a delay in keratinocyte migration. Wild type keratinocytes treated with NAB and Tgfb3-deficient keratinocytes closed an in vitro scratch wound with no delay, suggesting that our in vivo observations likely result from a paracrine effect.

Sterol intermediates of cholesterol biosynthesis inhibit hair growth and trigger an innate immune response in cicatricial alopecia

Primary cicatricial alopecia (PCA) is a group of inflammatory hair disorders that cause scarring and permanent hair loss. Previous studies have implicated PPARγ, a transcription factor that integrates lipogenic and inflammatory signals, in the pathogenesis of PCA. However, it is unknown what triggers the inflammatory response in these disorders, whether the inflammation is a primary or secondary event in disease pathogenesis, and whether the inflammatory reaction reflects an autoimmune process. In this paper, we show that the cholesterol biosynthetic pathway is impaired in the skin and hair follicles of PCA patients. Treatment of hair follicle cells with BM15766, a cholesterol biosynthesis inhibitor, or 7-dehydrocholesterol (7-DHC), a sterol precursor, stimulates the expression of pro-inflammatory chemokine genes. Painting of mouse skin with 7-DHC or BM15766 inhibits hair growth, causes follicular plugging and induces the infiltration of inflammatory cells into the interfollicular dermis. Our results demonstrate that cholesterologenic changes within hair follicle cells trigger an innate immune response that is associated with the induction of toll-like receptor (TLR) and interferon (IFN) gene expression, and the recruitment of macrophages that surround the hair follicles and initiate their destruction. These findings reveal a previously unsuspected role for cholesterol precursors in PCA pathogenesis and identify a novel link between sterols and inflammation that may prove transformative in the diagnosis and treatment of these disorders.

An overview of biological basis of pathologic scarring

AIMS AND OBJECTIVES

To review the current mechanisms and biologic processes leading to the formation of pathologic scars.

MATERIALS AND METHODS

A computerised literature search was carried out using MEDLINE for all published articles on ''pathologic scarring''. The medical subject headings ''scarring'' were combined with ''mechanisms''. A review of selected relevant literature was then undertaken.

RESULTS

Scarless embryonal healing tends to be characterised by minimal inflammatory reaction mediated by reduced IL6,IL8 and hyaluronidase while there are elevated levels of hyaluronic acid MMP1to3, as well as IL10.The multifunctional cytokine TGF-B, its several isoforms as well as its postreceptor signalling mechanisms appears to play the key role in the scarring process . There is also evidence to show that PDGF, IGF and other cytokines regulate scarring . While conventional antiscarring agents target the fibroplasia phase, others such as tamoxifen ,calcium channel blockers, and imidazolaquinolines targets various phases of the scarring process .

CONCLUSION

It appears that multiple mechanisms are involved in the phenotypical appearance of abnormal scarring. A deeper understanding of these mechanisms is pivotal to the development of better antiscarring therapies in the very near future .

[A long way to go in scar research-further enhancement of basic and clinical research of the scar]

Scar, either hypertrophic scar or keloid, is one of the most common complications due to proliferative disorder of fibrosis in the process of wound healing after burn injuries, trauma, and surgical operations. To repair the cosmetic and functional impairments caused by scars poses a great challenge to all the burn surgery workers. With the advances in both basic research and clinical treatment, the understanding of scar formation and the therapeutic strategies of scar have been improved significantly. However, the remaining problems are still outstanding. In this discussion, the advances and problems in the scientific research in this field, including genetic predisposition, candidate gene, dysfunction of fibroblasts, interaction between fibroblasts and keratinocytes, as well as animal models for hypertrophic scar and keloid were summarized. In addition, the progresses in the clinical therapies are also discussed, including pressure treatment, silicone gel sheeting, corticosteroids, laser, and other emerging treatment strategies. The understanding and treatment of scar will improve in the future with further deepening basic research and clinical trials with stricter standard of assessment.

[Pathogenesis of adhesions formation after intraabdominal operations]

The article describes the pathogenesis of adhesions formation after intraabdominal operations. Described predisposing factors leading of which is mechanical trauma, resulting from the use of surgical instruments, rough manipulations during surgery, damage to the mesothelium by dry gauze etc, which cause the adhesions. The pathogenesis of adhesions formation after intraabdominal surgery is presented in outline form, which described the changes occurring in the body starting with combination of predisposing factors and ending with the development of adhesions with blood vessels by 7-12 days after surgery. At the genetic level predisposition to adhesions formation and development of adhesive disease is treated as a manifestation of rapid acetylation phenotype, in which the intensity of fibrin formation exceeds normal rate of its catabolism. Thus, according to modem concepts, adhesive disease is a separate nosologic unit that dictates the necessity of its detailed study, development and introduction new universal methods of preventing the adhesions formation after intraabdominal operations.

Functional genomics unique to week 20 post wounding in the deep cone/fat dome of the Duroc/Yorkshire porcine model of fibroproliferative scarring

BACKGROUND

Hypertrophic scar was first described over 100 years ago; PubMed has more than 1,000 references on the topic. Nevertheless prevention and treatment remains poor, because 1) there has been no validated animal model; 2) human scar tissue, which is impossible to obtain in a controlled manner, has been the only source for study; 3) tissues typically have been homogenized, mixing cell populations; and 4) gene-by-gene studies are incomplete.

METHODOLOGY/PRINCIPAL FINDINGS

We have assembled a system that overcomes these barriers and permits the study of genome-wide gene expression in microanatomical locations, in shallow and deep partial-thickness wounds, and pigmented and non-pigmented skin, using the Duroc(pigmented fibroproliferative)/Yorkshire(non-pigmented non-fibroproliferative) porcine model. We used this system to obtain the differential transcriptome at 1, 2, 3, 12 and 20 weeks post wounding. It is not clear when fibroproliferation begins, but it is fully developed in humans and the Duroc breed at 20 weeks. Therefore we obtained the derivative functional genomics unique to 20 weeks post wounding. We also obtained long-term, forty-six week follow-up with the model.

CONCLUSIONS/SIGNIFICANCE

1) The scars are still thick at forty-six weeks post wounding further validating the model. 2) The differential transcriptome provides new insights into the fibroproliferative process as several genes thought fundamental to fibroproliferation are absent and others differentially expressed are newly implicated. 3) The findings in the derivative functional genomics support old concepts, which further validates the model, and suggests new avenues for reductionist exploration. In the future, these findings will be searched for directed networks likely involved in cutaneous fibroproliferation. These clues may lead to a better understanding of the systems biology of cutaneous fibroproliferation, and ultimately prevention and treatment of hypertrophic scarring.