Protein profiling of keloidal scar tissue

Proteomics as a tool to improve novel insights into skin diseases: what we know and where we should be going

Background

Biochemical processes involved in complex skin diseases (skin cancers, psoriasis, and wound) can be identified by combining proteomics analysis and bioinformatics tools, which gain a next-level insight into their pathogenesis, diagnosis, and therapeutic targets.

Methods

Articles were identified through a search of PubMed, Embase, and MEDLINE references dated to May 2022, to perform system data mining, and a search of the Web of Science (WoS) Core Collection was utilized to conduct a visual bibliometric analysis.

Results

An increased trend line revealed that the number of publications related to proteomics utilized in skin diseases has sharply increased recent years, reaching a peak in 2021. The hottest fields focused on are skin cancer (melanoma), inflammation skin disorder (psoriasis), and skin wounds. After deduplication and title, abstract, and full-text screening, a total of 486 of the 7,822 outcomes met the inclusion/exclusion criteria for detailed data mining in the field of skin disease tooling with proteomics, with regard to skin cancer. According to the data, cell death, metabolism, skeleton, immune, and inflammation enrichment pathways are likely the major part and hotspots of proteomic analysis found in skin diseases. Also, the focuses of proteomics in skin disease are from superficial presumption to depth mechanism exploration within more comprehensive validation, from basic study to a combination or guideline for clinical applications. Furthermore, we chose skin cancer as a typical example, compared with other skin disorders. In addition to finding key pathogenic proteins and differences between diseases, proteomic analysis is also used for therapeutic evaluation or can further obtain in-depth mechanisms in the field of skin diseases.

Conclusion

Proteomics has been regarded as an irreplaceable technology in the study of pathophysiological mechanism and/or therapeutic targets of skin diseases, which could provide candidate key proteins for the insight into the biological information after gene transcription. However, depth pathogenesis and potential clinical applications need further studies with stronger evidence within a wider range of skin diseases.

Krox20 Expression in Abnormal Scars: An Immunohistochemical Study

BACKGROUND

Scars are the end outcome of healing. They are grouped into several types, the common of which are keloid, hypertrophic and atrophic scars. The role of Krox20 in skin and hair physiology and pathology had emerged. Overexpression of Krox20 was sufficient to stimulate collagen gene expression and myofibroblast differentiation and is necessary for transforming growth factor-β (TGF-β) induced profibrotic responses.

OBJECTIVE

to investigate the role of Krox20 in abnormal scar pathogenesis. Hopefully, this insight can set the route for newer therapeutic approaches.

MATERIALS AND METHOD

This study was carried out on 30 cases [10 cases of keloid, 10 cases of atrophic scars and 10 cases with hypertrophic scars (HTS)] and 10 age and gender-matched apparently healthy subjects as a control group. Thirty biopsies were taken from perilesional areas. Evaluation of Krox20 expression was done using standard immunohistochemical technique.

RESULTS

Krox20 was downregulated in epidermis of scar biopsies compared to perilesional and normal skin (P=0.02) while it was overexpressed in fibroblasts in lesional scar biopsies compared to perilesional and normal skin (P<0.001). Keloid cases have significantly higher Krox20 expression in fibroblasts compared with HTS cases (P <0.001). Krox20 had significantly nucleocytoplasmic pattern of staining in scar cases compared with normal skin (P<0.001).

CONCLUSION

Krox20 overexpression may have a role in scar pathogenesis through up-regulation of multiple genes associated with tissue remodeling and wound healing. This may open an avenue for research for new therapies based on Krox20 inhibition.

Blood perfusion in hypertrophic scars and keloids studied by laser speckle contrast imaging

BACKGROUND

This study used laser speckle contrast imaging (LSCI) to evaluate the difference in blood perfusion between hypertrophic scars and keloids.

MATERIALS AND METHODS

A total of 30 keloids, 21 early hypertrophic scars, 20 proliferative hypertrophic scars, 20 regressive hypertrophic scars, and 20 mature hypertrophic scars were enrolled into this study. Vancouver Scar Scale (VSS) was assessed by a plastic surgeon. LSCI was used to evaluate perfusion of the whole (W), marginal (M), central (C) regions, and surrounding normal skin of the scars, and ratios (M/N, C/N) were calculated.

RESULTS

The perfusion of the marginal region in the keloid was significantly higher than that of the central region. Nevertheless, there was no significant difference in perfusion between the central and marginal regions in the early, proliferative, regressive, and mature hypertrophic scars. The degree of perfusion and perfusion ratio in the marginal region of keloid was similar to that of proliferative hypertrophic scars, and the degree of perfusion and perfusion ratio in central region of keloid group was similar to that of early and regressive hypertrophic scars.

CONCLUSIONS

The difference in perfusion distribution in keloids and hypertrophic scars may provide ideas for their identification. LSCI may be a useful method for differentiating between keloids and hypertrophic scars.

Intralesional excision as a surgical strategy to manage keloid scars: what's the evidence?

INTRODUCTION

Keloid scars are a particularly challenging clinical entity and a variety of management approaches have been described in the literature including intralesional surgery. The current literature lacks a summative review to ascertain the evidence base behind this surgical approach.

METHODS

A comprehensive English literature database search was performed using PubMed Medline, EMBASE and Web of Science from their individual dates of inception to March 2018. We present the different rationales proposed for the use of this technique, the clinical outcomes reported in the literature as well as the scientific basis for intralesional excision of keloid scars.

DISCUSSION

A number of arguments have been proposed to support intralesional excision including avoiding injury to neighbouring non-keloidal skin and the deep layer of the dermis, removal of the most proliferative fibroblastic group as well as debulking to facilitate the administration of injectable steroid. The most current literature does not provide sufficient support for the adoption of intralesional excisions based on data emerging from basic science as well as clinical outcome studies.

CONCLUSION

Emerging evidence supports the extralesional excision of keloid scars based on current mechanobiological, histological as well as clinical outcome data. Further trials comparing extralesional and intralesional surgical practices are eagerly awaited to ascertain the role of intralesional excisions in the keloid management arena.

The Superficial Dermis May Initiate Keloid Formation: Histological Analysis of the Keloid Dermis at Different Depths

Several studies have reported on certain aspects of the characteristics of different sites within a keloid lesion, but detailed studies on the keloid dermis at different depths within a keloid lesion are scarce. The aim of this study was to investigate the histology of the keloid dermis at different depths. This study included 19 keloid tissue samples that were collected from 19 patients and 19 normal skin samples, which were harvested from subjects without keloids or hypertrophic scar. Samples were studied by light microscopy using routine hematoxylin and eosin histochemical staining, and immunohistochemistry to detect CD20-positive B-lymphocytes and CD3-positive T-lymphocytes. Sirius Red histochemical staining was used to determine the type of collagen in keloid tissue and normal skin samples. The migratory properties of fibroblasts within the keloid dermis at different depths was compared, using an in vitro migration assay. The findings of this study showed that although the papillary and reticular dermis could be clearly distinguished in normal skin, three tissue layers were identified in the keloid dermis. The superficial dermis of keloid was characterized by active fibroblasts and lymphocytes; the middle dermis contained dense extracellular matrix (ECM) with large numbers fibroblasts, and the deep dermis was poorly cellular and characterized by hyalinized collagen bundles. In the keloid samples, from the superficial to the deep dermis, type I collagen increased and type III collagen decreased, and fibroblasts from the superficial dermis of the keloid were found to migrate more rapidly. In conclusion, the findings of this study showed that different depths within the keloid dermis displayed different biological features. The superficial dermis may initiate keloid formation, in which layer intralesional injection of pharmaceuticals and other treatments should be performed for keloid.

Hsp70 Knockdown by siRNA Decreased Collagen Production in Keloid Fibroblasts

PURPOSE

There are currently no consistently effective treatments for the excessive collagen produced by keloid fibroblasts. Previously, we reported that heat shock protein 70 (Hsp70) is up-regulated in keloid fibroblasts and keloid tissue. We, therefore, investigated whether Hsp70 is related to excessive collagen production in keloid fibroblasts.

MATERIALS AND METHODS

We inhibited Hsp70 in keloid fibroblasts by RNA interference and examined the resulting collagen expression. Thus, we selected small interfering RNAs (siRNAs) specific for human Hsp70, transfected them into keloid fibroblasts, and evaluated the resulting phenotypes and protein production using real-time polymerase chain reaction (PCR), Western blot, and a collagen assay.

RESULTS

The siRNAs dramatically suppressed Hsp70 mRNA expression, resulting in a decrease in collagen production in the keloid fibroblasts compared with controls. The siRNAs did not influence the viability of the keloid fibroblasts.

CONCLUSION

Hsp70 overexpression likely plays an important role in the excessive collagen production by keloid fibroblasts. RNA interference has therapeutic potential for the treatment of keloids.

Proteome profiling of human cutaneous leishmaniasis lesion

In this study, we used proteomics and biological network analysis to evaluate the potential biological processes and components present in the identified proteins of biopsies from cutaneous leishmaniasis (CL) patients infected by Leishmania braziliensis in comparison with normal skin. We identified 59 proteins differently expressed in samples from infected and normal skin. Biological network analysis employing identified proteins showed the presence of networks that may be involved in the cell death mediated by cytotoxic T lymphocytes. After immunohistochemical analyses, the expression of caspase-9, caspase-3, and granzyme B was validated in the tissue and positively correlated with the lesion size in CL patients. In conclusion, this work identified differentially expressed proteins in the inflammatory site of CL, revealed enhanced expression of caspase-9, and highlighted mechanisms associated with the progression of tissue damage observed in lesions.

Proteomic profiling reveals upregulated protein expression of hsp70 in keloids

Background. The biochemical characteristics of keloid-derived fibroblasts differ from those of adjacent normal fibroblasts, and these differences are thought to be the cause of abnormal fibrosis. Therefore, we investigated the characteristic proteins that are differentially expressed in keloid-derived fibroblasts using proteomics tools. Objective. We attempted to investigate the novel proteins that play important roles in the pathophysiology of keloids. Methods. Proteomics analysis was performed to identify differentially expressed proteins in keloid-derived fibroblasts. Keloid-derived fibroblasts and adjacent normal fibroblasts were analyzed with 2-DAGE. We validated these proteins with immunoblot analysis, real-time RT-PCR, and immunohistochemistry. Results. Sixteen differentially expressed protein spots were identified in keloid-derived fibroblasts. Among them, heat shock protein 70 (Hsp70) was specifically upregulated in keloid-derived fibroblasts. Also, immunohistochemistry and western blot analysis revealed increased Hsp70, TGF-β, and PCNA expressions in keloids compared to normal tissue. Conclusion. Hsp70 is overexpressed in keloid fibroblasts and tissue. The overexpression of Hsp70 may be involved in the pathogenesis of keloids, and the inhibition of Hsp70 could be a new therapeutic tool for the treatment of keloids.

Mechanosignaling pathways in cutaneous scarring

Mechanotransduction is the process by which physical forces are sensed and converted into biochemical signals that then result in cellular responses. The discovery and development of various molecular pathways involved in this process have revolutionized the fundamental and clinical understanding regarding the formation and progression of cutaneous scars. The aim of this review is to report the recent advances in scar mechanosignaling research. The mechanosignaling pathways that participate in the formation and growth of cutaneous scars can be divided into those whose role in mechanoresponsiveness has been proven (the TGF-β/Smad, integrin, and calcium ion pathways) and those who have a possible but as yet unproven role (such as MAPK and G protein, Wnt/β-catenin, TNF-α/NF-κB, and interleukins). During scar development, these cellular mechanosignaling pathways interact actively with the extracellular matrix. They also crosstalk extensively with the hypoxia, inflammation, and angiogenesis pathways. The elucidation of scar mechanosignaling pathways provides a new platform for understanding scar development. This better understanding will facilitate research into this promising field and may help to promote the development of pharmacological interventions that could ultimately prevent, reduce, or even reverse scar formation or progression.