Autophagy regulates lipid production and contributes to the sebosuppressive effect of retinoic acid in human SZ95 sebocytes.

BACKGROUND: Autophagy is a catabolic process for eliminating damaged organelles or proteins to maintain cellular homeostasis. Recently, lipids have been demonstrated to be targets for autophagosomal degradation. Therefore, autophagy might be involved in sebaceous gland homeostasis, however, relevant data are lacking. OBJECTIVES: We investigated the role of autophagy in sebaceous lipogenesis and its regulatory mechanisms in human SZ95 sebocytes. We also examined the possible role of autophagy in 13-cis-retinoic acid (13-cis-RA)-mediated sebosuppression. METHODS: Autophagy markers expression was examined by immunohistochemistry in normal and acne lesional skin. SZ95 sebocytes were treated with autophagy inhibitors under starvation or treated with a combination of testosterone and linoleic acid (testosterone/LA), with or without autophagy inducer rapamycin or 13-cis-RA. Lipids were assessed by BODIPY and quantitative Nile Red staining. Autophagy-related gene 7 small interference RNA was used to confirm the role of autophagy on the sebosuppressive effect of rapamycin or 13-cis-RA. RESULTS: Autophagy markers were strongly expressed in the maturing sebaceous gland cells in healthy skin, whereas downregulated in the acne-involved sebaceous glands. Testosterone/LA or insulin-like growth factor-1 inhibited starvation-induced sebocyte autophagy. Pharmacological inhibition of autophagy led to increased sebaceous lipid accumulation. Contrary, rapamycin inhibited the testosterone/LA-induced lipogenesis and expression of fatty acid synthesis genes via activating the autophagy pathway. 13-cis-RA increased autophagy in SZ95 sebocytes, partly via FoxO1 activation, and inhibition of autophagy abolished the sebosuppressive effect of 13-cis-RA. CONCLUSIONS: Autophagy plays an important role in the modulation of lipogenesis in human sebocytes and is involved in the sebostatic effect of 13-cis-RA.

Autophagy induction can regulate skin pigmentation by causing melanosome degradation in keratinocytes and melanocytes.

Autophagy regulates cellular turnover by disassembling unnecessary or dysfunctional constituents. Recent studies demonstrated that autophagy and its regulators play a wide variety of roles in melanocyte biology. Activation of autophagy is known to induce melanogenesis and regulate melanosome biogenesis in melanocytes. Also, autophagy induction was reported to regulate physiologic skin color via melanosome degradation, although the downstream effectors are not yet clarified. To determine the role of autophagy as a melanosome degradation machinery, we administered several autophagy inducers in human keratinocytes and melanocytes. Our results showed that the synthetic autophagy inducer PTPD-12 stimulated autophagic flux in human melanocytes and in keratinocytes containing transferred melanosomes. Increased autophagic flux led to melanosome degradation without affecting the expression of MITF. Furthermore, the color of cell pellets of both melanocytes and keratinocytes was visibly lightened. Inhibition of autophagic flux by chloroquine resulted in marked attenuation of PTPD-12-induced melanosome degradation, whereas the expression of melanogenesis pathway genes and proteins remained unaffected. Taken together, our results suggest that the modulation of autophagy can contribute to the regulation of melanocyte biology and skin pigmentation.

The newly developed single nucleotide polymorphism (SNP) markers for a potentially medicinal plant, Crepidiastrum denticulatum (Asteraceae), inferred from complete chloroplast genome data.

Medicinal effects of Crepidiastrum denticulatum have been previously reported. However, the genomic resources of this species and its applications have not been studied. In this study, based on the next generation sequencing method (Miseq sequencing system), we characterize the chloroplast genome of C. denticulatum which contains a large single copy (84,112 bp) and a small single copy (18,519 bp), separated by two inverted repeat regions (25,074 bp). This genome consists of 80 protein-coding gene, 30 tRNAs, and four rRNAs. Notably, the trnT_GGU is pseudogenized because of a small insertion within the coding region. Comparative genomic analysis reveals a high similarity among Asteraceae taxa. However, the junctions between LSC, SSC, and IRs locate in different positions within rps19 and ycf1 among examined species. Also, we describe a newly developed single nucleotide polymorphism (SNP) marker for C. denticulatum based on amplification-refractory mutation system (ARMS) technique. The markers, inferred from SNP in rbcL and matK genes, show effectiveness to recognize C. denticulatum from other related taxa through simple PCR protocol. The chloroplast genome-based molecular markers are effective to distinguish a potentially medicinal species, C. denticulatum, from other related taxa. Additionally, the complete chloroplast genome of C. denticulatum provides initial genomic data for further studies on phylogenomics, population genetics, and evolutionary history of Crepidiastrum as well as other taxa in Asteraceae.

Autophagy Activation by Crepidiastrum Denticulatum Extract Attenuates Environmental Pollutant-Induced Damage in Dermal Fibroblasts.

Pollution-induced skin damage results in oxidative stress; cellular toxicity; inflammation; and, ultimately, premature skin aging. Previous studies suggest that the activation of autophagy can protect oxidation-induced cellular damage and aging-like changes in skin. In order to develop new anti-pollution ingredients, this study screened various kinds of natural extracts to measure their autophagy activation efficacy in cultured dermal fibroblast. The stimulation of autophagy flux by the selected extracts was further confirmed both by the expression of proteins associated with the autophagy signals and by electron microscope. Crepidiastrum denticulatum (CD) extract treated cells showed the highest autophagic vacuole formation in the non-cytotoxic range. The phosphorylation of adenosine monophosphate kinase (AMPK), but not the inhibition of mammalian target of rapamycin (mTOR), was observed by CD-extract treatment. Its anti-pollution effects were further evaluated with model compounds, benzo[a]pyrene (BaP) and cadmium chloride (CdCl2), and a CD extract treatment resulted in both the protection of cytotoxicity and a reduction of proinflammatory cytokines. These results suggest that the autophagy activators can be a new protection regimen for anti-pollution. Therefore, CD extract can be used for anti-inflammatory and anti-pollution cosmetic ingredients.

The effect of autophagy-enhancing peptide in moisturizer on atopic dermatitis: a randomized controlled trial.

Background: Pentasodium tetracarboxymethyl palmitoyl dipeptide-12 (PTPD-12), a newly-synthesized peptide, enhances the autophagy activity, ultimately managing inflammation. Objective: To determine the effect of a new moisturizer containing PTPD-12 as the treatment of mild-to-moderate atopic dermatitis (AD). Methods: In this double-blind, randomized, placebo-controlled trial, 43 patients with mild-to-moderate AD were randomly assigned to either the PTPD-12 or control groups. Evaluations were performed at baseline, week 2, and week 4, including SCORing Atopic Dermatitis (SCORAD) index score, corneometry, trans-epidermal water loss (TEWL), visual analog scale (VAS) for pruritus, 7-point investigator's global assessment (IGA), and collection of adverse events. Results: The PTPD-12 group showed significant improvement with respect to SCORAD score, skin hydration, TEWL, and pruritus at weeks 2 and 4 when compared with baseline. Although the control group showed significant improvement regarding the SCORAD score and skin hydration, no significant change in TEWL or pruritus was demonstrated throughout the study. The mean changes in the SCORAD index score, skin hydration, TEWL, pruritus, and number of patients with improvement in IGA were not statistically different between the two groups. Conclusion: The moisturizer with autophagy-stimulating property provides a good therapeutic option to mild-to-moderate atopic dermatitis by contributing to skin barrier restoration and control of inflammation.

Antiaging and antioxidant effects of topical autophagy activator: A randomized, placebo-controlled, double-blinded study.

BACKGROUND: Recently, potential roles of autophagy in skin homeostasis received many interests. But, little has been reported for the potential antiaging effects of autophagy activator. OBJECTIVE: With the newly synthesized autophagy activator, heptasodium hexacarboxymethyl dipeptide-12 (Aquatide™) in vitro and clinical efficacy of the topical autophagy activator as an antiaging cosmeceutical ingredient was evaluated. METHODS: Antioxidant effect of Aquatide™ was evaluated by radical scavenging assay. In vitro effect was assessed by measuring the cytotoxicity of hydrogen peroxide in cultured normal human epidermal keratinocytes. Clinical evaluation was performed by a randomized, placebo-controlled, double-blinded study. Antioxidant efficacy was observed by measuring the carbonylated proteins in stratum corneum (SC) by fluorescein-5-thiosemicarbazide (FTZ) staining. RESULTS: Radical scavenging effects of Aquatide were observed with the ABTS assay, and significant reduction in hydrogen peroxide-induced cytotoxicity was observed in Aquatide™-treated cells. Autophagy inhibitor treatment abrogated cytoprotective effects of Aquatide™. In a clinical study, statistically significant increase in skin elasticity was observed after 4 and 8 weeks. Quantitative analysis of carbonylated proteins in SC also showed significant reduction in Aquatide™-treated group, which is consistent with the in vitro data. CONCLUSION: These results suggest that autophagy plays important roles in antioxidant system and aging process in skin, and topical autophagy activators can be potential cosmeceutical ingredients for skin antiaging.

Aquatide Activation of SIRT1 Reduces Cellular Senescence through a SIRT1-FOXO1-Autophagy Axis.

Ultraviolet (UV) irradiation is a relevant environment factor to induce cellular senescence and photoaging. Both autophagy- and silent information regulator T1 (SIRT1)-dependent pathways are critical cellular processes of not only maintaining normal cellular functions, but also protecting cellular senescence in skin exposed to UV irradiation. In the present studies, we investigated whether modulation of autophagy induction using a novel synthetic SIRT1 activator, heptasodium hexacarboxymethyl dipeptide-12 (named as Aquatide), suppresses the UVB irradiation-induced skin aging. Treatment with Aquatide directly activates SIRT1 and stimulates autophagy induction in cultured human dermal fibroblasts. Next, we found that Aquatide-mediated activation of SIRT1 increases autophagy induction via deacetylation of forkhead box class O (FOXO) 1. Finally, UVB irradiation-induced cellular senescence measured by SA-ß-gal staining was significantly decreased in cells treated with Aquatide in parallel to occurring SIRT1 activation-dependent autophagy. Together, Aquatide modulates autophagy through SIRT1 activation, contributing to suppression of skin aging caused by UV irradiation.

Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.