Shu Bin

Effect of asiaticoside on hypertrophic scar in the rabbit ear model.

Background:u2002 Previous observations suggested that asiaticoside had a possible antiscaring effect. However, the precise pathological mechanism still remain unknown. We questioned whether asiaticoside might alleviate the formation of hypertrophic scar by affecting the expression of Transform growth factor β (TGF‐β)/Smad signaling.

BMP‐7 attenuates TGF‐β1–induced fibroblast‐like differentiation of rat dermal papilla cells

Dermal papilla cells (DPCs) show phenotypic plasticity during wound healing. The multipotency of DPCs is well recognized, but the signaling pathways that regulate the differentiation of these cells into fibroblasts are poorly understood. A preliminary experiment showed that transforming growth factor beta1 (TGF‐β1) can induce DPCs to differentiate into fibroblast‐like cells, which suggests that DPCs may be a source of wound‐healing fibroblasts. Bone morphogenetic protein‐7 (BMP‐7), a member of the TGF‐β superfamily, can prevent and reverse fibrosis by counteracting the TGF‐β1–mediated profibrotic effect. To determine whether BMP‐7 attenuates the TGF‐β1–induced differentiation of DPCs into fibroblasts, we established an in vitro system for DPC differentiation and recorded the gene expression patterns that distinguished DPCs from fibroblasts. The proportion of fibroblast‐like cells was significantly enhanced in DPCs treated with TGF‐β1, as evidenced by immunocytochemistry, flow cytometry, quantitative real‐time reverse transcriptase polymerase chain reaction, and Western blot analysis. BMP‐7 and TGF‐β1 administration substantially decreased fibroblast‐like differentiation, indicating inhibition of TGF‐β1–induced differentiation. The antagonistic BMP‐7– and TGF‐β1–activated signaling pathways can be used to promote wound healing or suppress hypertrophic scarring.

Differentiation of rat dermal papilla cells into fibroblast-like cells induced by transforming growth factor β1.

Background: The origin of wound-healing fibroblasts is still debated. Dermal papilla cells (DPCs), which are an important population of stem cells for the regeneration of hair follicles, play a considerable role in cutaneous wound healing. Based on the plasticity of DPCs in wound healing, we hypothesized that DPCs may contribute to the fibroblast population of wound repair. Objective: To explore the possibility of differentiation of DPCs into fibroblasts induced by transforming growth factor β1 (TGF-β1). Methods: The fourth passage DPCs were treated with TGF-β1 (10 ng/mL) for 4 days, and a series of methods was used to observe morphologic changes under an inverted phase contrast microscope, to validate the messenger ribonucleic acid expression change in α-smooth muscle actin (α-SMA) and vimentin by quantitative real-time reverse transcriptase polymerase chain reaction (QRT-PCR), to analyze the expression of α-SMA and vimentin protein by flow cytometry, and to semiquantitatively measure the expression of fibroblast-specific protein 1 (FSP1) by Western blot. Results: DPCs treated with TGF-β1 presented fibroblast-like changes in morphology and immunocytochemistry. The effects of TGF-β1 on α-SMA and vimentin in DPCs were detected on both the transcriptional and the posttranscriptional levels. The results showed that TGF-β1 significantly downregulated α-SMA expression and enhanced the expression of vimentin at all times tested. Further study revealed that TGF-β1 could gradually promote the expression of FSP1 in a time-dependent manner. Conclusion: DPCs experienced the changes in molecular marker expression in response to TGF-β1, which may be a key source of fibroblasts in wound healing. Contexte: Lorigine des fibroblastes dans la cicatrisation fait encore lobjet de débats. Les cellules des papilles dermiques (CPD), qui constituent une population importante de cellules souches pour la régénération des follicules pileux, jouent un rôle considérable dans la cicatrisation du tissu cutané. Compte tenu de la plasticité des CPD dans la cicatrisation, nous avons émis lhypothèse selon laquelle les CPD pourraient contribuer à laccroissement de la population de fibroblastes dans la cicatrisation. Objectif: Létude visait à examiner la possibilité de différenciation des CPD en fibroblastes, provoquée par le facteur de croissance transformant β1 (TGF-β1). Méthodes: Les CPD ont été traités, au quatrième passage, au TGF-β1 (10 ng/mL), pendant 4 jours, et nous avons eu recours à la microscopie à contraste de phase inversée pour observer les changements morphologiques; à la réaction en chaîne par polymérase quantitative, en temps réel, après transcription inverse (RCP-TI) pour valider le changement dexpression de lacide ribonucléique messager de lactine des muscles lisses alpha (AMC-α) et de la vimentine; à la cytométrie de flux pour analyser lexpression des protéines dAMC-α et de vimentine; et au buvardage de Western pour obtenir une mesure semiquantitative de lexpression de la protéine 1 spécifique des fibroblastes (PSF1). Résultats: Les CPD traités au TGF-β1 ont subi des changements morphologiques et immunocytochimiques leur conférant un caractère fibroblastoïde. Les effets du TGF-β1 sur lAMC-α et la vimentine dans les CPD ont été détectés aux phases transcriptionnelle et posttranscriptionnelle. Daprès les résultats obtenus, le TGF-β1 a sensiblement régulé à la baisse lexpression de lAMC-α et intensifié lexpression de la vimentine, et ce, à tous les points de vérification dans le temps. Enfin, une étude complémentaire a révélé que le TGF-β1 pouvait favoriser graduellement lexpression de la PSF1 en fonction du temps. Conclusion: Les CPD ont subi des changements tels dexpression de marqueurs moléculaires, en réaction au TGF-β1, quils pourraient être une source importante de fibroblastes dans la cicatrisation.

Attenuation of α1 Collagen Production with Antisense Ribonucleic Acid in Cultured Hypertrophic Scar Fibroblasts

Background: It has been demonstrated that hypertrophic scar fibroblasts (HSFs) overexpress collagen messenger ribonucleic acid (mRNA) and protein, especially α1 collagen. Antisense nucleic acids are effective in inhibiting harmful or uncontrolled gene expression, suggesting that antisense ribonucleic acid (RNA) can effectively downregulate the expression of α1 collagen gene and attenuate the scars. Aims: This study was conducted to observe the effect of recombinant plasmid pREP9-COL1 on α1 collagen expression in HSFs and clarify the prospect of antisense RNA on scar treatment. Methods: The α1 collagen gene fragment including the region of 5′ UTR to exon (229 bp) was cloned in the eukaryotic expression plasmid pREP9 in the antisense orientation relative to the RSV-LTR promoter to reconstruct the pREP9- COL1 plasmid. Then it was transferred into HSFs through lipofectamine. The expression of α1 collagen was examined by immunostaining, reverse-transcriptase polymerase chain reaction, and Western blots. Results: The recombinant plasmid pREP9-COL1 with a correct sequence was constructed successfully; pREP9-COL1 consistently inhibited human α1 collagen gene expression at both mRNA and protein levels. Conclusions: Antisense RNA was effective in downregulating α1 collagen expression of HSFs. Therefore, this approach offered a prospect of scar treatment by attenuation of α1 collagen production with antisense RNA.