Knockdown of fibronectin extra domain B suppresses TGF-β1-mediated cell proliferation and collagen deposition in keloid fibroblasts via AKT/ERK signaling pathway.

Keloids represent a dermal fibrotic disease characterized by excess collagen deposition and invasion of normal skin beyond the wound boundary, similar to malignant tumor features. Fibronectin extra domain B (EDB) is highly expressed in many tumors but has not been studied in keloids. The present study aimed to investigate the expression and the influence of EDB on keloid and elucidate the putative signaling pathway. We examined expression of EDB and the effects of EDB on fibroblast proliferation, apoptosis and the expression of the related proteins and genes. The level of phosphorylation of Smad, ERK, and AKT was estimated to elucidate the signaling pathways. The results showed that EDB in human keloid tissues and fibroblasts was overexpressed. EDB knockdown suppressed the cell proliferation of keloid fibroblasts (KFs) treated by transforming growth factor-β1 (TGF-β1). Also, the phosphorylation of Smad, ERK, and AKT in TGF-β1-induced KFs was inhibited In addition, the low expression of pro-collagen-I (Col-I) and Col-III protein and mRNA level was observed in the siEDB group. EDB knockdown inhibited cell proliferation and suppressed collagen deposition in TGF-1-induced KFs. The underlying mechanism is the activation of TGF-β1/Smad, ERK, and AKT signaling pathways. Together, the results suggested that EDB is a promising therapeutic target for keloid clinical treatment.

Cui J ，Li Z ，Jin C ，Jin Z ... -  《-》

DKK3 regulates cell proliferation, apoptosis and collagen synthesis in keloid fibroblasts via TGF-β1/Smad signaling pathway.

It has been reported that Dickkopf-3 (DKK3) down-regulation was examined in keloid fibroblasts, but the biological functions of DKK3 have not yet been investigated. In this study, we examined the expression of DKK3 in human keloid tissues, further evaluated the biological function of DKK3 and explored its potential molecular mechanism in transforming growth factor-β1 (TGF-β1)-induced keloid fibroblasts. Our results showed that DKK3 mRNA expression in human keloid tissues is down-regulated. DKK3 overexpression inhibited cell proliferation in TGF-β1-induced keloid fibroblasts transfected with pcDNA3.1-DKK3. Furthermore, DKK3 overexpression remarkably upregulated the protein expression levels of Bax and caspase-3, but decreased the protein expression of Bcl-2. In addition, DKK3 overexpression dramatically inhibited the protein and mRNA levels of collagen I (Col-I), collagen III (Col-III) and α-smooth muscle actin (α-SMA). Moreover, the protein expression of TGF-β receptor I (TGF-β RI), TGF-β receptor II (TGF-β RII), the phosphorylation of Smad2 (p-Smad2) and Smad3 (p-Smad3) was dramatically inhibited by pcDNA3.1-DKK3. LY2109761, a TGF-β receptor inhibitor, also suppressed cell proliferation, apoptosis and collagen synthesis in TGF-β1-induced keloid fibroblasts. Taken together, DKK3 overexpression could inhibit cell proliferation, induced cell apoptosis, and suppressed collagen synthesis through TGF-β1/Smad signaling in TGF-β1-induced keloid fibroblasts. Our findings suggest that DKK3 is a novel and promising molecular target for keloid treatment.

Li Y ，Liu H ，Liang Y ，Peng P ，Ma X ，Zhang X ... -  《-》

Silencing NLRC5 inhibits extracellular matrix expression in keloid fibroblasts via inhibition of transforming growth factor-β1/Smad signaling pathway.

Dermal fibrosis is characterized by collagen accumulation and hyperproliferation of fibroblasts. NLRC5, as the largest member of nucleotide-binding domain and leucine-rich repeat (NLRs) family, has recently been implicated in the development of hepatic fibrosis. However, the role of NLRC5 in dermal fibrosis remains unknown. Therefore, herein, we investigated the effects of NLRC5 on keloid fibroblasts (KFs) and transforming growth factor-β1 (TGF-β1)-induced collagen expression and explored the underlying mechanism. We observed that NLRC5 mRNA and protein levels were highly expressed in KFs, silencing NLRC5 greatly suppressed TGF-β1-induced KFs proliferation. Silencing NLRC5 also obviously inhibited the expression of type I collagen, CTGF and α-smooth muscle actin (α-SMA) in human KFs induced by TGF-β1, as well as the expression of TGF-β receptor I and II. Furthermore, silencing NLRC5 suppressed the expression of TGF-β1-induced Smad2 and Smad3 phosphorylation in human KFs. Taken together, our study suggest that silencing NLRC5 reduced ECM expression in KFs through inhibiting the TGF-β1/Smad signaling pathway. Therefore, NLRC5 may represent a promising target for treatment of the keloid disease.

Ma HL ，Zhao XF ，Chen GZ ，Fang RH ，Zhang FR ... -  《-》

Aspidin PB, a novel natural anti-fibrotic compound, inhibited fibrogenesis in TGF-β1-stimulated keloid fibroblasts via PI-3K/Akt and Smad signaling pathways.

Keloid is an overgrowth of scar tissue that develops around a wound. The mechanisms of keloid formation and development still remain unknown, and no effective treatment is available. Searching for active natural resources may develop better prevention and treatment approaches for keloids. Aspidin PB is a natural resource with lower toxicity. We explored its effect on the regulation of TGF-β1-induced expression of type I collagen, CTGF, and α-SMA in keloid fibroblasts (KFs). Western blotting was used to detect the expression levels of type I collagen, CTGF, α-SMA, PI-3K/Akt and Smad-dependent and Smad-independent signaling pathway. The effect of aspidin PB on cell viability in human keloid fibroblasts was measured by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide). The percentage of the apoptotic cells was studied by flow cytometry. Based on our results, we revealed that aspidin PB inhibited the production of type I collagen, CTGF, and α-SMA in TGF-β1-induced KFs by blocking PI-3K/Akt signaling pathway. The TGF-β1-mediated phosphorylated levels of Smad2/3 were inhibited by aspidin PB pretreatment. Conclusively, our study suggests that aspidin PB has an inhibitory effect on fibrogenesis in TGF-β1-induced KFs. Our findings imply that aspidin PB has a therapeutic potential to intervene and prevent keloids and other fibrotic diseases.

Song R ，Li G ，Li S 《-》

Knockdown of IRF3 inhibits extracellular matrix expression in keloid fibroblasts.

Keloid is a pathologic fibro-proliferative disorder and is characterized by hyper-proliferation of fibroblasts and excess extracellular matrix (ECM) deposition. Interferon regulatory factor 3 (IRF3) is a member of the interferon-regulatory factor (IRF) family and has been shown to play a critical modulator in the progression of fibrosis. However, the function of IRF3 in dermal fibrosis remains unclear. Thus, in this study, we investigated the effects of IRF3 on keloid-derived fibroblasts (KFs) proliferation and ECM expression, and explored the underlying mechanism. Our results indicated that the expression of IRF3 was highly expressed in human keloid tissues. Down-regulation of IRF3 significantly inhibited KF proliferation and the expression of type I collagen and α-smooth muscle actin (α-SMA), as well as suppressed the expression of TGF-β receptor I and II in TGF-β1-stimulated KFs. Furthermore, down-regulation of IRF3 suppressed the phosphorylation levels of Smad2 and Smad3 in human KFs induced by TGF-β1. Taken together, our data showed that down-regulation of IRF3 inhibited the proliferation and ECM expression in KFs via suppressing the TGF-β1/Smad signaling pathway. Thus, our findings suggest that IRF3 may represent a promising target for treatment of the keloid disease.

Zhang Y ，Zhang L ，Lin XH ，Li ZM ，Zhang QY ... -  《-》