Nobiletin suppresses MMP-9 expression through modulation of p38 MAPK activity in human dermal fibrobalsts.

We aimed to identify a novel flavonoid from the in-house natural products to suppress matrix metalloproteases (MMPs), which is responsible for degradation of collagen and other extracellular matrix proteins. Total eight natural products were screened for identification of a novel MMP-9 suppressor using MMP-9 reporter system, where the prompt initial screening with multiple samples is readily examined. Among the extracts used in the present study, one extract (Citrus unshiu) was found active in this assay system. Furthermore, three representative flavonoids in this active extract of Citrus unshiu peel were tested in MMP-9 reporter system. Nobiletin (NB) of the tested flavonoids suppressed MMP-9 expression without cytotoxicity, which was validated by both real-time polymerase chain reaction (PCR) and zymography analyses. Sustained p38 mitogen activated protein kinase (MAPK) activity, closely associated with induction of MMP-9 under stress condition, was markedly reduced by NB treatment, which implies that modulation of p38MAPK by nobiletin is responsible for reduction of MMP9 expression. Hence, nobiletin, identified from MMP-9 reporter system based screening, may be further applied for the purpose of delaying collagen degradation in skin fibroblasts.

Extract of Aneilema keisak inhibits transforming growth factor-ß-dependent signalling by inducing Smad2 downregulation in keloid fibroblasts.

Keloids are characterised by the excessive accumulation of extracellular matrix (ECM), especially overabundant collagen formation. In keloid fibroblasts (KFs), transforming growth factor (TGF)-ß-dependent signalling is closely associated with a variety of keloid pathologic responses such as ECM production and fibroblast overgrowth. Thus, inhibition of TGF-ß signalling would be a potential therapeutic approach to prevent keloid scar formation. Thereby, we aimed to identify a novel TGF-ß signalling blocker among natural products using a simplified screening approach. We discovered that the extract of Aneilema keisak (A.K-Ex) lowered TGF-ß-dependent signalling by reducing Smad2 protein levels. Given that KFs showed altered dependency on TGF-ß for survival and proliferation, A.K-Ex-mediated reduction in Smad2 protein levels significantly inhibited the major characteristics of KFs such as cell growth, migration and collagen synthesis, suggesting that A.K-Ex exhibits possible therapeutic activity on keloids.

Negative regulation of stress-induced matrix metalloproteinase-9 by Sirt1 in skin tissue.

Solar ultra-violet (UV) radiation and the ensuing photo-damage are adverse factors affecting human skin directly exposed to the sun. Stress responses induced by UV radiation (UVR) elicit premature skin ageing (photoageing), resulting in extensive damage to dermal connective tissue. Disruption of the normal dermal structure of skin connective tissue, primarily collagen, impairs a variety of skin functions and is considered to be the main cause of wrinkle formation. Matrix metalloproteases (MMPs) may be responsible for the degradation of collagen and other extracellular matrix proteins, which are major targets for relieving skin photoageing. Herein, we demonstrated that Sirt1, a putative anti-ageing enzyme, reduced MMP-9 transcriptional expression in skin. The known agonists of Sirt1, resveratrol and metformin, also significantly inhibited MMP-9 expression and appeared to protect collagen from degradation after UVR. These studies suggest that the Sirt1 activator could be used as a novel therapeutic agent to delay skin photoageing.

Accelerated wound healing by S-methylmethionine sulfonium: evidence of dermal fibroblast activation via the ERK1/2 pathway.

S-Methylmethionine sulfonium (SMMS) is a derivative of the amino acid methionine, and is synthesized in a variety of plants. SMMS is widely referred to as vitamin U because of its potent therapeutic effect on gastrointestinal ulceration. Skin wounds are accompanied by mucosal erosion and share similar histopathological aspects with gastric ulcers, so it is plausible that SMMS may promote skin wound healing. In animal models, topical administration of SMMS for a given period of time, to both physical and chemical wounds, facilitated wound closure and promoted re-epithelialization compared with a control. In addition, single SMMS treatment was sufficient to promote the growth of human dermal fibroblasts (hDFs) as well as the migration of hDFs, which are indispensable steps for skin wound healing. The promotion of hDF proliferation and migration resulted from considerable activation of ERK1/2 by SMMS, and inhibition of ERK activity by a chemical inhibitor significantly abrogated both the promoted proliferation and migration of hDFs. Therefore, we concluded that SMMS facilitated the repair process of skin damage by activation of dermal fibroblasts, which suggests that SMMS has potential as a skin wound-healing agent.

Effects of repetitive photodynamic therapy using indocyanine green for acne vulgaris.

BACKGROUND: Indocyanine green (ICG) is a photosensitizer recently introduced for the treatment of acne. OBJECTIVE: To evaluate the efficacy and safety of photodynamic therapy (PDT) using ICG in subjects with acne vulgaris and to evaluate whether there was a difference in the efficacy of ICG-PDT between different numbers of treatment. MATERIALS AND METHODS: Subjects with acne on the face were included. ICG lotion (0.1%) was applied for 30 minutes, and a long pulse diode laser was used. Three or five treatments per subject were performed over 2 weeks. Acne lesion counts and Leeds revised acne grades were evaluated at baseline and 2 weeks after the last treatment. RESULTS: In total, 47 subjects completed the study. After both three and five ICG-PDT sessions, a significant reduction in acne lesions and significant improvement in Leeds revised acne grades were found in all treated subjects compared to baseline. In the subjects receiving five ICG-PDT sessions, the reduction of papules/pustules was greater than in the subjects receiving three ICG-PDT sessions (P < 0.01, respectively). However, there was no significant change in the count of nodules/cysts, although it is a negative trend (P = 0.066). Adverse effects were minimal. CONCLUSION: ICG-PDT using long-pulsed diode laser can be a safe and effective tool for acne vulgaris. Moreover, repetitive treatments of five can cause further improvement of inflammatory acne lesions.