Effects of Xanthium stramarium and Psoralea corylifolia Extracts Combined with UVA1 Irradiation on the Cell Proliferation and TGF-β1 Expression of Keloid Fibroblasts

Natural products - Dawn of keloid treatment

Keloids are prevalent pathological scars, often leading to cosmetic deformities and hindering joint mobility.They cause discomfort, including burning and itching, while gradually expanding and potentially posing a risk of cancer.Developing effective drugs and treatments for keloids has been a persistent challenge in the medical field. Natural products are an important source of innovative drugs and a breakthrough for many knotty disease.Herein, keywords of "natural, plant, compound, extract" were combined with "keloid" and searched in PubMed and Google Scholar, respectively. A total of 32 natural products as well as 9 extracts possessing the potential for treating keloids were ultimately identified.Current research in this field faces a significant challenge due to the lack of suitable animal models, resulting in a predominant reliance on in vitro studies.In vivo and clinical studies are notably scarce as a result.Moreover, there is a notable deficiency in research focusing on the role of nutrients in keloid formation and treatment.The appropriate dosage form (oral, topical, injectable) is crucial for the development of natural product drugs. Finally, the conclusion was hereby made that natural products, when used as adjuncts to other treatments, hold significant potential in the management of keloids.By summarizing the natural products and elucidating their mechanisms in keloid treatment, the present study aims to stimulate further discoveries and research in drug development for effectively addressing this challenging condition.

Wnt2 knock down by RNAi inhibits the proliferation of in vitro-cultured human keloid fibroblasts

To study the effect of knocking down wingless-related MMTV integration site 2 (Wnt2) expression by RNAi on the growth and signaling pathways of ex vitro-cultured keloid fibroblasts (KFB).Human KFB were isolated from 10 keloid patient specimens. The KFB cells were then transfected with 4 pairs of small interfering RNA (siRNA) targeting human Wnt2, respectively. Reverse transcriptase-polymerase chain reaction and Western blot analysis were conducted to verify the knock down of Wnt2, and the expression of β-catenin glycogen synthase kinase-3β (GSK-3β) and cyclin D1 were examined.siRNA Wnt2 transfection (siWnt2) resulted in the significant inhibition of Wnt2 expression at both the mRNA and protein levels. The expression of β-catenin, GSK-3β, p-GSK-3β, and cyclin D1 at the protein level also decreased in siWnt2 cells. siWnt2 resulted in a substantially slower growth and significant delay in cell doubling time of the KFB cells compared with control groups. Further, the siRNA knock down of GSK-3β and β-catenin resulted in slower proliferation rates, respectively.Wnt2 siRNA has an inhibitive effect on keloid fibroblast proliferation, which may be a potential therapeutic approach for keloid and other human fibrotic diseases.

The antifibrotic effect of isolate tagitinin C from tithonia diversifolia (Hemsley) A. Gray on keloid fibroblast cell

Introduction

Keloids characterized by fibroblast hyperproliferation and depositions of collagen which similar to cancer cells. Tagitinin C is a class of sesquiterpene lactones (SLS) was isolated from the leaves of the moon flower Tithonia diversifolia (Hemsley) A. Gray. The study aim is to evaluate the effects of tagitinin C from Tithonia diversifolia to keloid fibroblasts (KF).

Methods

Monolayer cultures of keloid fibroblast (three passages) were treated with 8 serial concentration of tagitinin C (0.015 to 2) μg/mL during 72 and 120 hours. A positive control using mitomycin C. Cellular viabilities were measured by MTT assay. Collagen depositions were measured by Sirius Red assay for nonsoluble collagen.

Results

The reading of the result was conducted by ELISA reader. Data were analyzed by probit regression with SPSS 19 for Windows. The result showed that tagitinin C can inhibit keloid fibroblasts (KF) viability with IC₅₀ 0.122 μg/mL (incubation 72h) and 0.039 μg/mL (120h), whereas mitomycin C IC₅₀ 0.120 μg/mL (72h) and IC₅₀ of 0.100 μg/mL (120h). At IC₅₀ concentration of tagitinin C on keloid collagen deposition 53.1% (72h) and 44.3% (120h), whereas the IC₅₀ concentration of mitomycin C on keloid collagen deposition 60.4% (72h) and 52.1% (120h). Selectivity index tagitinin C on normal fibroblasts (NF) is 287 for 72h incubation and 791 for 120h incubation.

Conclusion

It can be concluded that the ability of tagitinin C inhibits KF viability and decreasing keloid collagen deposition is consistent with the concentration (concentration-dependent) and incubation time (time-dependent). Tagitinin C has a low toxicity level on NF with high selectivity index.

Low-Level Light Therapy with 410 nm Light Emitting Diode Suppresses Collagen Synthesis in Human Keloid Fibroblasts: An In Vitro Study

Background

Keloids are characterized by excessive collagen deposition in the dermis, in which transforming growth factor β (TGF-β)/Smad signaling plays an important role. Low-level light therapy (LLLT) is reported as effective in preventing keloids in clinical reports, recently. To date, studies investigating the effect of LLLT on keloid fibroblasts are extremely rare.

Objective

We investigated the effect of LLLT with blue (410 nm), red (630 nm), and infrared (830 nm) light on the collagen synthesis in keloid fibroblasts.

Methods

Keloid fibroblasts were isolated from keloid-revision surgery samples and irradiated using 410-, 630-, 830-nm light emitting diode twice, with a 24-hour interval at 10 J/cm². After irradiation, cells were incubated for 24 and 48 hours and real-time quantitative reverse transcription polymerase chain reaction was performed. Western blot analysis was also performed in 48 hours after last irradiation. The genes and proteins of collagen type I, TGF-β1, Smad3, and Smad7 were analyzed.

Results

We observed no statistically significant change in the viability of keloid fibroblasts after irradiation. Collagen type I was the only gene whose expression significantly decreased after irradiation at 410 nm when compared to the non-irradiated control. Western blot analysis showed that LLLT at 410 nm lowered the protein levels of collagen type I compared to the control.

Conclusion

LLLT at 410 nm decreased the expression of collagen type I in keloid fibroblasts and might be effective in preventing keloid formation in their initial stage.

Pretreatment of Ferulic Acid Protects Human Dermal Fibroblasts against Ultraviolet A Irradiation

Background

Approximately 90%~99% of ultraviolet A (UVA) ray reaches the Earth's surface. The deeply penetrating UVA rays induce the formation of reactive oxygen species (ROS), which results in oxidative stress such as photoproducts, senescence, and cell death. Thus, UVA is considered a primary factor that promotes skin aging.

Objective

Researchers investigated whether pretreatment with ferulic acid protects human dermal fibroblasts (HDFs) against UVA-induced cell damages.

Methods

HDF proliferation was analyzed using the water-soluble tetrazolium salt assay. Cell cycle distribution and intracellular ROS levels were assessed by flow cytometric analysis. Senescence was evaluated using a senescence-associated β-galactosidase assay, while Gadd45α promoter activity was analyzed through a luciferase assay. The expression levels of superoxide dismutase 1 (SOD1), catalase (CAT), xeroderma pigmentosum complementation group A and C, matrix metalloproteinase 1 and 3, as well as p21 and p16 were measured using quantitative real-time polymerase chain reaction.

Results

Inhibition of proliferation and cell cycle arrest were detected in cells that were irradiated with UVA only. Pretreatment with ferulic acid significantly increased the proliferation and cell cycle progression in HDFs. Moreover, ferulic acid pretreatment produced antioxidant effects such as reduced DCF intensity, and affected SOD1 and CAT mRNA expression. These effects were also demonstrated in the analysis of cell senescence, promoter activity, expression of senescent markers, and DNA repair.

Conclusion

These results demonstrate that ferulic acid exerts protective effects on UVA-induced cell damages via anti-oxidant and stress-inducible cellular mechanisms in HDFs.

Oxidative Damage and Nuclear Factor Erythroid 2-Related Factor 2 Protein Expression in Normal Skin and Keloid Tissue

Background

Reactive oxygen species (ROS) play an important role in the induction of apoptosis under pathological conditions. Recently, a significant increase in ROS production and disrupted apoptosis mechanisms in keloids have been reported. Nuclear factor erythroid 2-related factor 2 (Nrf2) represents one of the most important cellular defense mechanisms against oxidative stress and is implicated in the regulation of apoptosis. Recently, it has been reported that Nrf2 upregulates Bcl-2, an anti-apoptotic protein.

Objective

To compare Nrf2 protein expression in normal skin tissues to keloid tissues.

Methods

ROS generation in keloid tissues was evaluated with OxyBlot analysis. Western blotting and/or immunohistochemical staining approaches were used to study expression of Nrf2 or Bcl-2 in keloid and normal skin tissues. Cellular fractionation was performed to examine subcellular distribution of Nrf2. Transfection of fibroblasts with Nrf2-specific small interfering RNA (siRNA) was conducted to understand the relationship between Nrf2 expression and apoptosis induction.

Results

Protein oxidation, a marker of oxidative stress, is increased in keloid tissues. Western blot analysis clearly showed that Nrf2 and Bcl-2 are downregulated in keloid tissues. Immunohistochemical staining of Nrf2 confirmed the results of the western blot analysis. Transfection of fibroblasts with the Nrf2-specific siRNA results in increased apoptosis and decreased cell viability.

Conclusion

Collectively, our data indicate that Nrf2 expression is downregulated in keloid tissues, and that Nrf2 is involved in the development of apoptosis in Nrf2 siRNA-transfected fibroblasts. We propose that a defective antioxidant system and apoptotic dysregulation may participate in keloid pathogenesis.

Mast cell chymase in keloid induces profibrotic response via transforming growth factor-β1/Smad activation in keloid fibroblasts

This study was to examine whether mast cell chymase exists in human keloids and exerts its profibrotic effect via transforming growth factor-β1/Smad signaling pathway. The number of mast cells and the expression levels of chymase in keloids and normal skin were examined by immunohistochemistry assays. The mRNA expression and activity changes of chymase in keloids and normal skin were determined by real-time quantitative PCR and radioimmunoassay. After keloid fibroblasts were treated with different concentrations of chymase (0, 15, 30, 60, and 120 ng/mL) for various time periods, the proliferation of keloid fibroblasts, collagen synthesis, mRNA and protein expression of TGF-β1, and the protein expression of phosphorylated Smad2/3, Smad2/3 and Smad7 were investigated using MTT assay, ELISA and Western blotting. Mast cells and chymase exist in keloid. Gene expression and activity of mast cell chymase in keloid are significantly higher than those in normal skin. Chymase promotes keloid fibroblast proliferation and collagen synthesis by activating TGF-β1. The activation of Smad protein signaling pathway by chymase is related to the elevated P-Smad protein expression in keloid fibroblasts. Our data demonstrated that mast cell chymase plays an important role in keloid formation through TGF-β1/Smad signaling pathway.