Keratinocyte outgrowth from human skin explant cultures is dependent upon p38 signaling

Organ culture of skin is known to recapitulate several early events in the process of wound healing. Here we investigate the function of p38 kinase signaling as a regulator of keratinocyte behavior in human skin organ culture. We first show that skin organ culture recapitulates the transition from migration to proliferation that is known to characterize the reepithelialization process. We next show that inhibition of p38 markedly impairs the formation of keratinocyte outgrowth in human skin explant cultures, as well as the migration of keratinocytes in an in vitro wound assay. In contrast, the marked induction of mRNA encoding the ErbB ligand heparin-binding epidermal growth factor-like growth factor, known to occur after skin wounding, was not blocked by inhibition of p38. As assessed by immunoblotting, phosphorylation of p38 was limited and was not increased between 0 and 7 days of organ culture. Our results show the sensitivity of reepithelialization to inhibition by p38 and suggest that p38 acts primarily during the migration phase of this process. These data also indicate that autocrine heparin-binding epidermal growth factor expression is not regulated by p38.     

The effects of caffeine on wound healing

The purine alkaloid caffeine is a major component of many beverages such as coffee and tea. Caffeine and its metabolites theobromine and xanthine have been shown to have antioxidant properties. Caffeine can also act as adenosine‐receptor antagonist. Although it has been shown that adenosine and antioxidants promote wound healing, the effect of caffeine on wound healing is currently unknown. To investigate the effects of caffeine on processes involved in epithelialisation, we used primary human keratinocytes, HaCaT cell line and ex vivo model of human skin. First, we tested the effects of caffeine on cell proliferation, differentiation, adhesion and migration, processes essential for normal wound epithelialisation and closure. We used 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) proliferation assay to test the effects of seven different caffeine doses ranging from 0·1 to 5 mM. We found that caffeine restricted cell proliferation of keratinocytes in a dose‐dependent manner. Furthermore, scratch wound assays performed on keratinocyte monolayers indicated dose‐dependent delays in cell migration. Interestingly, adhesion and differentiation remained unaffected in monolayer cultures treated with various doses of caffeine. Using a human ex vivo wound healing model, we tested topical application of caffeine and found that it impedes epithelialisation, confirming in vitro data. We conclude that caffeine, which is known to have antioxidant properties, impedes keratinocyte proliferation and migration, suggesting that it may have an inhibitory effect on wound healing and epithelialisation. Therefore, our findings are more in support of a role for caffeine as adenosine‐receptor antagonist that would negate the effect of adenosine in promoting wound healing.     

Apoptotic bodies extracted from adipose mesenchymal stem cells carry microRNA-21–5p to induce M2 polarization of macrophages and augment skin wound healing by targeting KLF6

BackgroundAdipose-derived mesenchymal stem cells (adMSCs) are suggested as potential tools for the treatment of regenerative diseases, including tissue repair. This study aimed to explore the function of adMSC-derived apoptotic bodies in skin wound healing and the molecules of action.MethodsThe acquired adMSCs and their-derived apoptotic bodies were identified. A murine model of full-thickness skin wounds was treated with apoptotic bodies. The wound healing process of mice and the pathological changes in wound tissues were examined. Ana-1 macrophages were treated with lipopolysaccharide (LPS) and apoptotic bodies for in vitro experiments. Polarization of macrophages was examined by immunofluorescence staining of the specific biomarkers and ELISA kits. Dermal microvascular endothelial cells (DMECs) or dermal fibroblasts (DFs) were co-cultured with apoptotic bodies or the LPS- and apoptotic bodies-treated Ana-1 cells. Downstream molecules mediated by apoptotic bodies were screened by microarray and bioinformatic analyses.ResultsApoptotic bodies treatment accelerated skin wound healing in mice and promoted formation of granulation tissues and blood vessels in wound tissues. Apoptotic bodies treatment induced M2 polarization of macrophages. The angiogenesis ability of DMECs, and the viability and migration of DFs were increased when co-cultured with the apoptotic bodies-treated Ana-1 cells. MicroRNA (miR)-21–5p was abundantly expressed in ABs, and kruppel like factor 6 (KLF6) mRNA was confirmed as a target of miR-21–5p. Overexpression of KLF6 reduced M2 polarization of macrophages and blocked the promoting effect of apoptotic bodies on wound healing in vitro and in vivo.ConclusionmiR-21–5p carried by adMSC-derived apoptotic bodies targets KLF6 to induce M2 polarization of macrophages and augment skin wound healing.     

Long non-coding RNA HOXA11-AS contributes to the formation of keloid by relieving the inhibition of miR-182-5p on ZNF217

BackgroundLong non-coding RNA (lncRNA) dysregulation is demonstrated to be associated with disease progression. Mounting studies show that lncRNA promotes or inhibits the development of keloid. We aimed to disclose the role of homebox A11 antisense RNA (HOXA11-AS) in the formation of keloid.MethodsQuantitative real-time PCR (qPCR) was adopted for expression analysis of HOXA11-AS, miR-182-5p and zinc finger protein 217 (ZNF217) mRNA, and the expression of ZNF protein and marker proteins was detected by western blot. Cell proliferation, cell migration and cell apoptosis were investigated using CCK-8 assay, wound healing assay and flow cytometry assay, respectively. The potential interplay between miR-182-5p and HOXA11-AS or ZNF217 was verified by dual-luciferase reporter assay, RIP assay and pull-down assay. The role of HOXA11 in vivo was studied by establishing animal models.ResultsHOXA11-AS was highly expressed in tissues and fibroblasts of keloid. Deficiency of HOXA11-AS blocked the proliferation and migration of keloid fibroblasts and induced fibroblast apoptosis. HOXA11-AS directly combined to miR-182-5p whose downregulation reversed the effects of HOXA11-AS knockdown. ZNF217 was a target of miR-182-5p, and HOXA11-AS indirectly promoted ZNF217 expression by binding to miR-182-5p. MiR-182-5p enrichment also blocked keloid fibroblast proliferation, survival and migration, while further ZNF217 overexpression abolished these effects. HOXA11-AS knockdown also hindered the growth of keloid in mouse models.ConclusionHigh expression of HOXA11-AS promoted the formation and growth of keloid through the upregulation of ZNF217 by targeting miR-182-5p, and the inhibition of HOXA11-AS might be a novel strategy to prevent keloid development.     

Long non-coding RNA H19 promotes the proliferation,migration and invasion while inhibits apoptosis of hypertrophic scarring fibroblasts by targeting miR-3187-3p/GAB1 axis

BackgroundIt had been reported that long non-coding RNA (lncRNA) H19 was associated with the proliferation of fibroblasts. However, the regulatory mechanism of H19 remains unclear. Thus, the study was designed to explore the underlying mechanism of H19 in the process of Hypertrophic scarring (HS).MethodsThe expression levels of H19, miR-3187-3p, and growth factor receptor binding 2-associated binding protein 1 (GAB1) in HS tissues and HS fibroblasts were measured by real-time quantitative polymerase chain reaction (RT-qPCR) assay. The biological behaviors of HS fibroblasts, such as cell proliferation, apoptosis, migration, and invasion were assessed by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT), colony formation, flow cytometry, and transwell assays, respectively. The protein expression level was quantified by western blot assay. The interaction association between miR-3187-3p and H19 or GAB1 was predicted by Starbase database analysis and confirmed by dual-luciferase reporter assay, respectively.ResultsH19 was significantly increased in HS tissues and HS fibroblasts. Loss-of-functional experiments revealed that knockdown of H19 inhibited the development of HS. Moreover, silencing of H19 impeded the proliferation, migration, and invasion, while enhanced apoptosis of HS fibroblasts by increasing miR-3187-3p expression. In addition, overexpression of GAB1 could abolish miR-3187-3p overexpression-induced effects on cell proliferation, apoptosis, migration, and invasion of HS fibroblasts. Mechanistically, H19 could act as a sponge of miR-3187-3p to upregulate the expression of GAB1 in HS fibroblasts.ConclusionCollectively, our results revealed that H19 promoted the proliferation, migration, and invasion, while impeded apoptosis of HS fibroblasts by targeting miR-3187-3p/GAB1 axis.     

Inhibition of bone morphogenetic protein signalling promotes wound healing in a human ex vivo model

Background

Bone morphogenetic proteins (BMPs) and their receptors (BMPRs) play roles in embryonic development and postnatal remodelling of the skin. Many indications suggest that BMP signalling regulates keratinocyte proliferation and differentiation. Chronic wounds have been shown to exhibit high levels of BMP ligands; however, the effect of BMP pathway modulation on human skin healing remains undefined.

Methods

A human ex vivo skin wound healing model was used to analyse the expression of BMP signalling pathway components during healing and to investigate the effects of BMPs and the BMP antagonist Noggin on skin repair. Additionally, the effects of BMP signalling on keratinocyte proliferation, apoptosis and migration were tested using in vitro flow cytometry and ‘scratch’ migration assays, respectively.

Results

BMP receptor-1B (BMPR-1B) and downstream signalling protein phosphorylated-Smad-1/5/8 were highly expressed in healing epidermis. Treatment of human skin with exogenous BMPs impaired wound closure by reducing keratinocyte proliferation and increasing apoptosis. The BMP antagonist Noggin negated the inhibitory effects of BMP ligands, and when used alone, Noggin reduced keratinocyte apoptosis in the wound bed. In vitro, BMP ligands suppressed keratinocyte proliferation whilst Noggin stimulated proliferation. Keratinocyte migration was slowed following BMP treatment; in contrast, migration was significantly accelerated due to inhibition of BMP activity by either Noggin or BMPR-1B silencing.

Conclusions

BMP signalling is inherently involved in wound healing. BMPs slow skin repair by suppressing keratinocyte proliferation and migration. Thus, modulation of BMP signalling using BMP inhibitors such as Noggin may serve as a new approach to promote cutaneous wound repair.Level of evidence: Not ratable.

     

miR-195-5p通过靶向ROCK1抑制肾癌细胞迁移、侵袭和上皮-间质转化

目的探讨miR-195-5p对肾癌细胞迁移、侵袭和上皮-间质转化的影响。方法通过转染miR-195-5p mimics或inhibitors分别过表达或抑制肾癌细胞中miR-195-5p的表达,转染靶向Rho相关螺旋蛋白激酶1(ROCK1)的小干扰RNA敲低肾癌细胞中ROCK1的表达量,利用细胞划痕实验和Transwell小室实验分别检测肾癌细胞的迁移和侵袭能力。通过双荧光素酶报告实验验证miR-195-5p对ROCK1的靶向调控作用,利用免疫印迹试验检测ROCK1及上皮-间质转化相关蛋白的表达水平。结果过表达miR-195-5p可显著抑制肾癌细胞的迁移、侵袭和上皮-间质转化,而抑制miR-195-5p的表达可明显促进肾癌细胞的迁移、侵袭和上皮-间质转化(P<0.05)。miR-195-5p可通过靶向ROCK1调控其在肾癌细胞中表达。敲低ROCK1后可部分抵消miR-195-5p inhibitors对肾癌细胞迁移、侵袭和上皮-间质转化的影响。结论miR-195-5p可通过靶向ROCK1抑制肾癌细胞的迁移、侵袭和上皮-间质转化。     

microRNA-139-5p及其靶基因Notch1在结直肠癌中的作用

目的：探讨microRNA-139-5p（miR-139-5p）在结直肠癌中的表达及其对结直肠癌细胞转移和侵袭的影响。 方法：用荧光定量PCR方法检测miR-139-5p在结直肠癌组织与不同结直肠癌细胞株中的表达变化;用Boyden小室分析和伤口愈合实验检测miR-139-5p转染及miR-139-5p抑制对结直肠癌细胞转移和侵袭能力的影响;生物信息学方法预测miR-139-5p的靶基因,并采用荧光素酶报告基因实验验证,Western blot方法检测miR-139-5p转染对靶基因表达的影响。 结果：与各自的正常对照组比较,结直肠癌组织与结直肠癌细胞系中miR-139-5p表达均明显降低（P<0.05）。结直肠癌DLD1细胞和HCT116细胞转染miR-139-5p后,转移与侵袭能力均明显降低（均P<0.05）,而miR-139-5p抑制剂处理后,两种细胞的的侵袭能力均明显增强（均P<0.05）。生物信息学预测显示,Notch1是miR-139-5p的靶基因,且得到荧光素报告实验结果证实。Western blot结果显示,转染miR-139-5p后,结直肠癌DLD1细胞和HCT116细胞中Notch1蛋白表达均明显下调（均P<0.05）。 结论：miR-139-5p可能通过调节Notch1的表达而抑制肿瘤细胞的转移和侵袭,而下调的miR-139-5p可能在结直肠癌的发生发展中起了重要作用。     

Use of an in vitro model of tissue-engineered human skin to study keratinocyte attachment and migration in the process of reepithelialization

To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo.     

microRNA-449a靶向Notch1抑制膀胱癌细胞J82的迁移

【摘要】〓目的〓研究microRNA-449a(miR-449a)对膀胱癌细胞J82迁移能力的影响以及对靶基因Notch1表达的影响。方法〓通过mimics转染膀胱癌细胞株J82使其过表达miR-449a,利用Transwell实验、细胞划痕实验观察细胞迁移能力的变化;采用实时定量PCR和蛋白印迹检测细胞Notch1表达水平的变化,并通过荧光素酶实验验证miR-449a与Notch1基因的直接调控关系。结果〓与对照组相比,转染miR-449a组的J82细胞的迁移能力减弱。过表达miR-449a后,J82细胞Notch1的mRNA表达无明显变化(P=0.5739),但Notch1蛋白表达下调(P=0.0135)。荧光素酶报告基因实验显示,miR-449a能明显抑制Notch1-3’UTR的荧光素酶活性(P=0.0016)。结论〓过表达miR-449a可能通过靶向降低Notch1基因的蛋白表达,抑制膀胱癌细胞的迁移。     

Decreased expression of miR-204-3p in peripheral blood and wound margin tissue associated with the onset and poor wound healing of diabetic foot ulcers

To investigate the relationship between small non-coding RNA-204-3p (miR-204-3p) and the onset and wound healing of diabetic foot ulcers (DFU) and the underlying molecular mechanism, sixty four newly diagnosed patients with T2DM without DFU (T2DM group), 82 T2DM patients with DFU (DFU group), and 60 controls with normal glucose tolerance (NC group) were included. Quantitative real-time PCR (qRT-PCR) method was used to determine miR-204-3p expression levels in peripheral blood and wound margin tissue of subjects, and to analyse the relationship between the expression of miR-204-3p and wound healing. In vitro experiments were also performed to understand the effect of miR-204-3p on high glucose induced injury of HaCaT cells (human keratinocytes). The results showed that miR-204-3p expression level of peripheral blood in the T2DM group was marked lower than that in the NC group [2.38 (1.31-5.04) vs 3.27 (1.51-6.98)] (P < .05). Similarly, the miR-204-3p expression level of peripheral blood in the DFU group was significantly lower than the T2DM group [1.15 (0.78-2.89) vs 2.38 (1.31-5.04)] (P < .01). The expression level of miR-204-3p in peripheral blood and wound margin tissues of DFU patients was positively correlated with the healing rate of foot ulcers after 8 weeks (P < .05). Multifactorial logistic regression analysis showed that decreased expression of miR-204-3p in peripheral blood was an independent risk factor for DFU (OR = 2.95, P < .05). The results of in vitro experiments showed that miR-204-3p could improve the proliferation and migration of HKC cells and reduce the proportion of apoptosis of HKC cells by targeted regulation of zinc finger protein Kruppel like factor 6 (KLF6) in high glucose environment. Therefore, the decreased expression of miR-204-3p in peripheral blood and wound tissue of T2DM patients is closely related to the occurrence and poor wound healing of DFU. The down-regulated expression of miR-204-3p can reduce its ability to antagonise the functional damage of keratinocytes induced by high-glucose conditions. These results will provide potential targets for the treatment of DFU.     

miR-34b-5p promotes renal cell inflammation and apoptosis by inhibiting aquaporin-2 in sepsis-induced acute kidney injury

ObjectiveThis study was designed to uncover the mechanism of miR-34b-5p-mediated aquaporin-2 (AQP2) in sepsis-induced injury using human renal tubular epithelial cells (HK-2).MethodsSerum levels of miR-34b-5p, TNF-α, IL-1β, IL-6, serum creatinine (SCr), and blood urea nitrogen (BUN) in septic patients with acute kidney injury (AKI) and healthy controls were detected. Lipopolysaccharide (LPS) was used to induce sepsis in HK-2 cells. LPS-induced HK-2 cells were transfected with miR-34b-5p inhibitor, miR-34b-5p mimic, pcDNA3.1-AQP2, si-AQP2, miR-34b-5p inhibitor + si-NC, or miR-34b-5p inhibitor + si-AQP2. The expressions of miR-34b-5p, AQP2, Bax, Bcl-2, cleaved caspase-3, TNF-α, IL-1β, and IL-6 in HK-2 cells were detected. TUNEL staining revealed the apoptosis of HK-2 cells. Dual-luciferase reporter assay verified the binding between miR-34b-5p and AQP2.ResultsThe expression of miR-34b-5p and the inflammatory responses were augmented in septic AKI patients. miR-34b-5p was up-regulated and AQP2 was down-regulated in LPS-induced HK-2 cells. miR-34b-5p inhibition or AQP2 overexpression ameliorated apoptosis and inflammation in LPS-induced HK-2 cells. In contrast, overexpressing miR-34b-5p deteriorated LPS-induced injury in HK-2 cells. AQP2 was a downstream target of miR-34b-5p. AQP2 silencing abolished the suppressive effects of miR-34b-5p inhibition on LPS-induced apoptosis and inflammatory response in HK-2 cells.ConclusionmiR-34b-5p inhibits AQP2 to promote LPS-induced injury in HK-2 cells.     

Extracellular matrix-derived tripeptide proline-glycine-proline inhibits keratinocyte proliferation and migration

Keratinocytes are the predominant cell type in epidermis, and are primarily responsible for the epithelialization phase of wound healing. Previous studies by our group showed a positive correlation between IL‐8 concentration and delayed healing of porcine cutaneous partial‐thickness wounds. Interleukin‐8 and collagen‐breakdown product N‐acetyl‐Pro‐Gly‐Pro (PGP) are known as chemoattractant molecules for neutrophils during inflammation. The activity of both molecules is dependent on chemokine receptors CXCR1 and CXCR2. In addition to neutrophils, keratinocytes also express CXCR1 and CXCR2. Here we investigated the effects of IL‐8 and PGP on keratinocyte proliferation and migration. Our results showed that IL‐8 up to 100 ng/mL does not have any significant impact on keratinocyte proliferation or migration. ECM‐derived tripeptide PGP chemotactically attracts neutrophils but not keratinocytes. PGP strongly inhibits keratinocyte proliferation and migration in a cell‐type specific manner. Thus, collagen breakdown product PGP plays a key role in modulating both the inflammatory and epithelialization phases of wound healing.     

MiR-669b-3p regulates CD4+ T cell function by down-regulating indoleamine-2, 3-dioxygenase

ObjectiveAcute rejection is a major cause of morbidity and mortality after solid organ transplantation. Therefore, optimizing treatment strategies and improving curative effect is urgent and necessary. Reliable biomarkers for acute rejection and the underlying molecular mechanisms remain to be determined.MethodsIn this study, we established a mouse-to-mouse cardiac transplantation model and identified miR-669b-3p as a potential biomarker of acute rejection using a microRNA polymerase chain reaction (PCR)-based chip assay.ResultsFurther analyses showed that miR-669b-3p negatively regulated indoleamine-2,3-dioxygenase (IDO), a rate-limiting enzyme of tryptophan catabolism inhibiting T cell function. Using mixed lymphocyte reaction assay, we showed that miR-669b-3p increased proliferation stimulation index and inhibited apoptosis in CD4⁺ T cells. Moreover, miR-669b-3p regulated the expression of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and Interleukin 10 (IL-10) and contributed to cytokine shift towards a Th2-dominant response.ConclusionOur results advance the current understanding of the immune regulatory function of miRNA and shed light on the role of miR-669b-3p in CD4⁺ T cells, suggesting that miR-669b-3p is a potential target for acute allograft rejection.     

Knockdown of circ_0026579 ameliorates lipopolysaccharide (bacterial origin)-induced inflammatory injury in bronchial epithelium cells by targeting miR-338-3p/TBL1XR1 axis

BackgroundCircular RNAs (circRNAs) play an important regulatory role in human diseases including organ allograft rejection. The aim of this study is to clarify the functional role and molecular mechanism of circ_0026579 RNA in lipopolysaccharide (LPS)-induced bronchopneumonia injury.Materials and methodsBronchial epithelial BEAS-2B cells were treated with LPS to mimic an in vitro model for bronchopneumonia. Cell viability and proliferation were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-ethynyl-2′-deoxyuridine (EdU) assay. Flow cytometry assay was used to assess cell apoptosis. Caspase-3 activity was analyzed by Caspase-3 activity assay kit. The expression levels of circ_0026579 RNA, miR-338-3p, and transducin β-like 1× related protein 1 (TBL1XR1) RNA were determined by RT-qPCR. The protein level was quantified by western blot assay. The correlation between miR-338-3p and circ_0026579 or TBL1XR1 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays.ResultsLPS treatment repressed proliferation but induced apoptosis and inflammatory response in BEAS-2B cells. Circ_0026579 RNA was highly expressed in patients with pneumonia. Besides, the expression levels of circ_0026579 RNA and TBL1XR1 RNA/protein were upregulated, while miR-338-3p level was decreased in LPS-treated BEAS-2B cells. Knockdown of circ_0026579 RNA or TBL1XR1 protein could abolish LPS-induced cell injury in BEAS-2B cells. Furthermore, we found that circ_0026579 RNA functioned as a “sponge” for miR-338-3p to regulate TBL1XR1 expression. Additionally, silencing circ_0026579 RNA protected BEAS-2B cells from LPS-induced bronchopneumonia injury by regulating TBL1XR1 expression.ConclusionCirc_0026579 RNA knockdown promoted cell proliferation but inhibited apoptosis and inflammation in LPS-induced BEAS-2B cells through regulating miR-338-3p RNA/TBL1XR1 protein axis.     

Lesional skin in vitiligo exhibits delayed in vivo reepithelialization compared to the nonlesional skin

Vitiligo, a common skin disorder, is characterized by the loss of functional melanocytes resulting in the depigmentation of skin. Previous studies have demonstrated molecular and architectural alterations in the epidermal keratinocytes upon loss of melanocytes. The physiological implications of these “altered” keratinocytes are yet not known. We investigated the wound healing efficiency of lesional vs nonlesional skin in 12 subjects with stable nonsegmental vitiligo using histological and ultrastructural evaluation of partial‐thickness wounds. The wounds were examined 12 days postinjury, coinciding with the reepithelialization phase of healing marked primarily by keratinocyte migration and proliferation. This study demonstrated a significant difference in the reepithelialization potential between the lesional and nonlesional skin. While all 12 nonlesional wounds demonstrated considerable neoepidermis formation on the 12th day post wound, only four of the corresponding lesional samples showed comparable reepithelialization; the rest remaining in the inflammatory phase. Ultrastructural studies using transmission electron microscopy as well as immunohistochemical staining revealed a reduced number of desmosomes, shorter keratin tonofilaments and an increase in myofibroblast population in the dermis of lesional reepithelialized tissue compared to the nonlesional reepithelialized samples. This study implicates gross functional perturbations in the lesional skin during physiological wound healing in vitiligo, suggesting that the breakdown of keratinocyte‐melanocyte network results in delayed wound repair kinetics in the lesional skin when compared to patient‐matched nonlesional skin.