The ameliorative effect of hemp seed hexane extracts on the Propionibacterium acnes-induced inflammation and lipogenesis in sebocytes.

In this study, we investigated the anti-microbial, anti-inflammatory, and anti-lipogenic effects of hemp (Cannabis sativa L.) seed hexane extracts, focusing on the Propionibacterium acnes-triggered inflammation and lipogenesis. Hemp seed hexane extracts (HSHE) showed anti-microbial activity against P. acnes. The expression of iNOS, COX-2, and the subsequent production of nitric oxide and prostaglandin increased after infection of P. acnes in HaCaT cells, however, upon treating with HSHE, their expressions were reduced. P. acnes-induced expressions of IL-1ß and IL-8 were also reduced. HSHE exerted anti-inflammatory effects by regulating NF-κB and MAPKs signaling and blunting the translocation of p-NF-κB to the nucleus in P. acnes-stimulated HaCaT cells. Moreover, P. acnes-induced phosphorylation of ERK and JNK, and their downstream targets c-Fos and c-Jun, was also inhibited by HSHE. In addition, the transactivation of AP-1 induced by P. acnes infection was also downregulated by HSHE. Notably, HSHE regulated inflammation and lipid biosynthesis via regulating AMPK and AKT/FoxO1 signaling in IGF-1-induced inflammation and lipogenesis of sebocytes. In addition, HSHE inhibited 5-lipoxygenase level and P. acnes-induced MMP-9 activity, and promoted collagen biosynthesis in vitro. Thus, HSHE could be utilized to treat acne vulgaris, through its anti-microbial, anti-inflammatory, anti-lipogenic, and collagen-promoting properties.

Polyphenol-rich apple extract inhibits dexamethasone-induced sebaceous lipids production by regulating SREBP1 expression.

Sebum production and excretion is a primary function of the sebaceous glands, but abnormally increased sebum production is a major cause of acne vulgaris. To identify a new candidate that regulates sebum production, we investigated the possible inhibitory effects of apple polyphenols (APP) purified from unripe apples on primary cultured human sebocytes and in patients with acne vulgaris. Dexamethasone (Dex) increased lipid synthesis and expression of the sterol response element-binding protein 1 (SREBP 1) and its target enzymes, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), in the sebocytes. However, APP inhibited Dex-induced lipid production and expression of SREBP-1, ACC and FAS. APP also inhibited the increase in the expression and activation of glucocorticoid receptor in the sebocytes. Taken together, these results suggest that APP may be useful to regulate sebum production and may alleviate sebum-involved skin disease, such as acne vulgaris.

Inhibitory effect of imperatorin on insulin-like growth factor-1-induced sebum production in human sebocytes cultured in vitro.

AIMS: Acne is a common skin disease that originates in the sebaceous gland. The pathogenesis of acne is very complex, involving the increase of sebum production and perifollicular inflammation. In this study, we screened the anti-lipogenic material and demonstrated its effect using cultured human sebocytes. MAIN METHODS: Normal human sebocytes were cultured by explanting the sebaceous glands. To evaluate the anti-lipogenic effect, sebocytes were treated with test materials and (14)C-acetate incorporation assay was performed. KEY FINDINGS: To screen the anti-lipogenic materials, we tested the effect of many herbal plant extracts. We found that Angelica dahurica extract inhibited the insulin-like growth factor-1 (IGF-1)-induced sebum production in terms of squalene synthesis in sebocytes. Furthermore, imperatorin isolated from A. dahurica showed remarkable inhibitory effect on squalene production as well as squalene synthase promoter activity. To investigate the putative action mechanism, we tested the effect of imperatorin on intracellular signaling. The results showed that imperatorin inhibited IGF-1-induced phosphorylation of Akt. In addition, imperatorin significantly down-regulated PPAR-γ and SREBP-1, the important transcription factors for lipid synthesis. SIGNIFICANCE: These results suggest that imperatorin has a potential for reducing sebum production in sebocytes, and can be applicable for acne treatment.

Testosterone synthesized in cultured human SZ95 sebocytes derives mainly from dehydroepiandrosterone.

Human sebaceous gland possesses all the steroidogenic enzymes required for androgen synthesis. It remains unclear whether the testosterone produced in situ mainly derives from circulating dehydroepiandrosterone (DHEA) or from de novo synthesis utilizing serum cholesterol. Using testosterone radioimmunoassay, we found that testosterone was barely detectable in the supernatant of cultured human SZ95 sebocytes when cholesterol was added alone, indicating a low basal expression of steroidogenic acute regulatory protein (StAR) in SZ95 cells. Human chorionic gonadotropin and fibroblast growth factor-9 were as potent as forskolin in activating StAR to enhance testosterone production, while interleukin-1 beta, dexamethasone, insulin and insulin-like growth factor-1 showed no stimulatory effect. A two-fold increase of testosterone production was observed in supplementation of DHEA as compared to pregnenolone, progesterone or 17 alpha-hydroxyprogesterone. Based on our findings, testosterone synthesized in cultured sebocytes derived mainly from DHEA and inhibition of 3beta-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase may be a new target of androgen suppression for acne treatment.

Acne vaccines targeting Propionibacterium acnes.

Acne vulgaris is one of the most common skin diseases and can affect a large number of individuals at some point in their lives. Though the disease is multi-factorial, the Gram-positive, anaerobic bacterium Propionibacterium acnes (P. acnes), a member of resident skin microflora, is implicated in acne inflammation and associated with acne lesions. Common treatments such as antibiotic or benzoyl peroxide nonspecifically reduce bacteria population on the skin, which may disrupt homeostasis and cause further complications such as promoting growth of antibiotic-resistant bacteria strains. A component vaccine and an inactivated whole bacteria vaccine are made to target specifically P. acnes. The component vaccine targeting P. acnes surface sialidase and heat-inactivated P. acnes vaccine have both been shown to reduce P. acnes- induced inflammation in vivo and neutralize P. acnes in vitro, suggesting their potentials as new treatment for acne vulgaris. To facilitate acne studies, a bioengineering approach was utilized to design a new human acne model using tissue chamber. The tissue chamber of human sebocytes is shown to produce in mice a microenvironment similar to human acne inflammation. This approach can also be utilized in future studies in developing therapeutic acne vaccines and designing possible combined treatment of acne vaccine with alternative acne treatments.

Augmentation of sebaceous lipogenesis by an ethanol extract of Grifola frondosa (Maitake mushroom) in hamsters in vivo and in vitro.

Grifola frondosa (Maitake mushroom) is an edible and medicinal mushroom with versatile effects such as antitumor and immunomodulating actions. Here, we demonstrated that an ethanol extract of G. frondosa fruiting body (Maitake extract) augmented intracellular lipid droplet formation and the production of triacylglycerols (TG), a major component of sebum, along with the activation of diacylglycerol acyltransferase, a rate-limiting enzyme of TG synthesis in cultured hamster sebocytes. The topical treatment of Maitake extract on the skin of hamster auricles augmented sebum accumulation in sebaceous glands and ducts. However, in comparison with the Maitake extract, another ethanol extract prepared from Agaricus blazei Murill showed less activity in sebaceous lipogenesis in hamsters in vivo and in vitro. These results provide novel evidence that Maitake extract augments sebaceous lipogenesis in hamsters in vivo and in vitro. Thus, Maitake extract is likely to be a unique agent leading to the remission of dry skin.

Organ maintenance of human sebaceous glands: in vitro effects of 13-cis retinoic acid and testosterone.

Human sebaceous glands were isolated by shearing, and maintained for 7 days either on defined medium, on medium supplemented with 3 microM-testosterone or on medium supplemented with both 3 microM-testosterone and 1 microM-13-cis retinoic acid. Freshly isolated glands retained their in vivo morphology. On maintenance, the glands retained their freshly isolated rates of cell division, but the sebocytes showed increased keratinization and there was multilayering of the peripheral undifferentiated cells. However, glands maintained in the presence of 1 microM-13-cis retinoic acid showed very little luminal keratinization and only a small degree of multilayering. On autoradiography, freshly isolated glands retained their in vivo pattern of [methyl-3H]thymidine incorporation. Similar patterns were seen when glands were maintained for 7 days with or without testosterone. However, in the presence of both testosterone and 13-cis retinoic acid there was only slight graining. Following 7 days maintenance the rate of lipogenesis fell significantly. This was partially reversed by testosterone, but further inhibited by 13-cis retinoic acid. The patterns of lipids that are synthesised after a week's maintenance are very similar to those seen in freshly isolated glands, except that the squalene:cholesterol ratio is reversibly regulated by 3 microM-testosterone and 1 microM-retinoic acid. Protein synthesis was maintained at the same rates as for freshly isolated glands under all conditions of maintenance. Whereas DNA synthetic rates were maintained in the presence of testosterone, they were significantly inhibited by 13-cis retinoic acid. Glandular wet weights were retained under all conditions of maintenance, except that they were significantly reduced by 13-cis retinoic acid. This study shows that human sebocytes continue to divide on organ maintenance, but that they do not differentiate fully. However, this provides the first demonstration that 13-cis retinoic acid acts on human sebaceous glands directly, reducing the rate of cell division and the rate of lipogenesis, which shows that the maintained human sebaceous gland might provide a useful model for studying the effect of 13-cis retinoic acid on human sebocytes.

On the influence of topically applied drugs on cell kinetics in the sebaceous gland. Investigations with the example of selenium disulfide in the Syrian hamster ear.

60 male Syrian hamsters were treated on one ear with 2.5% selenium disulfide in a surfactant base and on the other ear with the same surfactant base. After treatment 15 animals were investigated by 3H-thymidine autoradiography, 15 animals by the colcemid method and 15 animals by the in vivo double labelling technique with 3H- and 14C-thymidine. In 15 animals the porportion of labeled cells was determined which still had contact with the basal lamina in the sebaceous gland 6 days after 3H-thymidine injection. Besides an increase in sebaceous gland size and in cell proliferation, a shortening of the S phase and a reduction of the labeled sebaceous gland cells which still have contact with the basal lamina of the sebaceous gland 6 days after 3H - thymidine injection were determined.