Gene expression profile of primary fibroblasts from keloid and normal skin treated with palm oil tocotrienol rich fraction (TRF)
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Date
2013-07
Authors
Kamarulzaman, Siti Arffah
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Keloids are dermal fibroproliferative disease that developed due to abnormal wound response in predisposed individuals. The alteration of growth factors and cytokines in abnormal healing process formed an imbalanced condition between collagen and other extracellular matrix components synthesis and degradation. Various treatments for keloids have been tried but most of the therapeutic approaches remain clinically unsatisfactory. Tocotrienols have gained increasing scientific interest due to their antioxidant and related protective properties. However, there is lack of scientific evidence regarding the efficacy and therapies of tocotrienol in keloid and scar management. Thus, this study was carried out to investigate the effects of palm oil tocotrienol rich fraction (TRF) on human keloid fibroblasts. Keloids and normal skin were collected as samples in this study. Primary human dermal fibroblast from normal skin and keloid tissues were successfully cultured. Heat-shock protein 47 (HSP47) and fibroblast surface protein (FSP) antibody markers were used for primary normal human dermal fibroblast (pNHDF) verification. pNHDF was positively stained after incubation with HSP47 and FSP antibodies. To differentiate growth characteristic between nHDF and keloid fibroblast (KF), the cell viability for both cells were assessed using trypan blue dye. Both nHDF and KF exhibited linear growth pattern but KF grew faster compared to nHDF. The percentage of viable cells of nHDF and KF were assessed by 3-
(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay in order to evaluate cytotoxic and suppressive effects of TRF. The percentage of viable cells of nHDF significantly (p <0.05) increased in a time dependent manner when nHDF treated with concentrations of TRF at 0.16 μg/ml to 19.5 μg/ml. An opposite result was seen when nHDF were treated with TRF at concentrations of 39 μg/ml and 78 μg/ml. The percentage of viable cells of KF decreased in a time dependent manner when KF treated with all concentrations except at 19.5 μg/ml. At concentration of 19.5 μg/ml, the percentage of viable cells of KF increased over the incubation time. TRF at concentration of 39 μg/ml significantly (p <0.01) suppressed KF cells growth. However, TRF at highest concentration (78 μg/ml) was found to be cytotoxic to both nHDF and KF. Microarray gene expression using Illumina HumanRef-8 Expression BeadChips was used to identify the changes in gene expressions in KF in response to TRF. There were 906 genes found to be significantly (p <0.05) differentially expressed with at least a 2 fold change in treated KF compared to untreated KF. 524 genes were up-regulated and 382 genes were down-regulated in treated KF. The expression of transforming growth factor-beta I (TGFβ1), transforming growth factor-beta II (TGFβ2), transforming growth factor-beta III (TGFβ3), collagen type III alpha I (COL3A1), fibronectin (FN1), transgelin (TAGLN) and insulin-like growth factor-binding protein 5 (IGFBP5) was validated using real-time PCR. Interestingly, TRF down regulates the expression of certain genes that are commonly highly expressed in KF such as genes that are involved in ECM-receptor interaction and cell cycle pathways, ECM components, fibrosis-inducing cytokines, cell growth and wound healing. TRF appeared to reverse the abnormal expression of TGFβ2, COL3A1, FN1, TAGLN and IGFBP5 genes in KF. The findings of this study concluded that TRF has a suppressive effect on KF. These
indicated that TRF have a significant health promoting effects through its excellent anti-fibrogenic effect on KF based on its ability to induce ECM degradation and inhibit the overproduction of collagen and other ECM components. These results provide valuable finding for cosmetic reasons because considering its safety profile, TRF represents a promising therapeutic strategy to treat keloid scarring or to prevent its development.
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Keywords
Keloids