Beyond DNA sensing: expanding the role of cGAS/STING in immunity and diseases.

Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) is a DNA sensor that elicits a robust type I interferon response by recognizing ubiquitous danger-associated molecules. The cGAS/stimulator of interferon genes (cGAS/STING) is activated by endogenous DNA, including DNA released from mitochondria and extranuclear chromatin, as well as exogenous DNA derived from pathogenic microorganisms. cGAS/STING is positioned as a key axis of autoimmunity, the inflammatory response, and cancer progression, suggesting that the cGAS/STING signaling pathway represents an efficient therapeutic target. Based on the accumulated evidence, we present insights into the prevention and treatment of cGAS/STING-related chronic immune and inflammatory diseases. This review presents the current state of clinical and nonclinical development of modulators targeting cGAS/STING, providing useful information on the design of therapeutic strategies.

Loganin Prevents Hepatic Steatosis by Blocking NLRP3 Inflammasome Activation.

Activation of the NLRP3 inflammasome is a necessary process to induce fibrosis in nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH) is a kind of NAFLD that encompasses the spectrum of liver disease. It is characterized by inflammation and ballooning of hepatocytes during steatosis. We tested whether inhibiting the NLRP3 inflammasome could prevent the development and pathology of NASH. We identified loganin as an inhibitor of the NLRP3 inflammasome and investigated whether in vivo administration of loganin prevented NASH symptoms using a methionine-choline deficient (MCD) diet model in mice. We found that loganin inhibited the NLRP3 inflammasome activation triggered by ATP or nigericin, as shown by suppression of the production of interleukin (IL)-1ß and caspase-1 (p10) in mouse primary macrophages. The speck formation of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) was blocked by loganin, showing that the assembly of the NLRP3 inflammasome complex was impaired by loganin. Administration of loganin reduced the clinical signs of NASH in mice fed the MCD diet, including hepatic inflammation, fat accumulation, and fibrosis. In addition, loganin reduced the expression of NLRP3 inflammasome components in the liver. Our findings indicate that loganin alleviates the inflammatory symptoms associated with NASH, presumably by inhibiting NLRP3 inflammasome activation. In summary, these findings imply that loganin may be a novel nutritional and therapeutic treatment for NASH-related inflammation.

RIG-I Deficiency Promotes Obesity-Induced Insulin Resistance.

Inflammation and immunity are linked to the onset and development of obesity and metabolic disorders. Pattern recognition receptors (PRRs) are key regulators of inflammation and immunity in response to infection and stress, and they have critical roles in metainflammation. In this study, we investigated whether RIG-I (retinoic acid-inducible gene I)-like receptors were involved in the regulation of obesity-induced metabolic stress in RIG-I knockout (KO) mice fed a high-fat diet (HFD). RIG-I KO mice fed an HFD for 12 weeks showed greater body weight gain, higher fat composition, lower lean body mass, and higher epididymal white adipose tissue (eWAT) weight than WT mice fed HFD. In contrast, body weight gain, fat, and lean mass compositions, and eWAT weight of MDA5 (melanoma differentiation-associated protein 5) KO mice fed HFD were similar to those of WT mice fed a normal diet. RIG-I KO mice fed HFD exhibited more severely impaired glucose tolerance and higher HOMA-IR values than WT mice fed HFD. IFN-ß expression induced by ER stress inducers, tunicamycin and thapsigargin, was abolished in RIG-I-deficient hepatocytes and macrophages, showing that RIG-I is required for ER stress-induced IFN-ß expression. Our results show that RIG-I deficiency promotes obesity and insulin resistance induced by a high-fat diet, presenting a novel role of RIG-I in the development of obesity and metabolic disorders.

Topical application of celastrol alleviates atopic dermatitis symptoms mediated through the regulation of thymic stromal lymphopoietin and group 2 innate lymphoid cells.

Atopic dermatitis is a chronic inflammatory skin disease, of which incidence is closely related to exposure to environmental pollutants and allergens. Thymic stromal lymphopoietin (TSLP) plays an important role in the early stages of atopic dermatitis development by inducing Th2 immune responses. In addition, TSLP regulates activation of group 2 innate lymphoid cells (ILC2), promoting the pathogenesis of atopic dermatitis. The aim of this study was to investigate whether celastrol alleviated atopic dermatitis symptoms by regulating TSLP expression and ILC2 stimulation. Celastrol suppressed TSLP production in mouse keratinocyte cells by inhibiting NF-ĸB activation. Topical application of celastrol significantly improved atopic dermatitis symptoms induced by house dust mite (HDM) in NC/Nga mice as determined by dermatitis score and histological assessment. Celastrol decreased the levels of TSLP in atopic dermatitis skin lesions of HDM-stimulated NC/Nga mice. Celastrol reduced levels of Th2 cytokines including IL-4, IL-5, and IL-13 in atopic dermatitis skin lesions of NC/Nga mice. Further, celastrol significantly reduced ILC2 population in atopic dermatitis skin lesions of NC/Nga mice. These results indicate that topical application of celastrol improved atopic dermatitis symptoms by lowering TSLP levels and concomitant immune responses. Data demonstrated that reduced TSLP levels and associated lower number of ILC2 cells alleviate atopic dermatitis symptoms induced by house dust mite.

Oxidized Phospholipids in Tumor Microenvironment Stimulate Tumor Metastasis via Regulation of Autophagy.

Oxidized phospholipids are well known to play physiological and pathological roles in regulating cellular homeostasis and disease progression. However, their role in cancer metastasis has not been entirely understood. In this study, effects of oxidized phosphatidylcholines such as 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) on epithelial-mesenchymal transition (EMT) and autophagy were determined in cancer cells by immunoblotting and confocal analysis. Metastasis was analyzed by a scratch wound assay and a transwell migration/invasion assay. The concentrations of POVPC and 1-palmitoyl-2-glutaroyl-sn-glycero-phosphocholine (PGPC) in tumor tissues obtained from patients were measured by LC-MS/MS analysis. POVPC induced EMT, resulting in increase of migration and invasion of human hepatocellular carcinoma cells (HepG2) and human breast cancer cells (MCF7). POVPC induced autophagic flux through AMPK-mTOR pathway. Pharmacological inhibition or siRNA knockdown of autophagy decreased migration and invasion of POVPC-treated HepG2 and MCF7 cells. POVPC and PGPC levels were greatly increased at stage II of patient-derived intrahepatic cholangiocarcinoma tissues. PGPC levels were higher in malignant breast tumor tissues than in adjacent nontumor tissues. The results show that oxidized phosphatidylcholines increase metastatic potential of cancer cells by promoting EMT, mediated through autophagy. These suggest the positive regulatory role of oxidized phospholipids accumulated in tumor microenvironment in the regulation of tumorigenesis and metastasis.

Therapeutic regulation of the NLRP3 inflammasome in chronic inflammatory diseases.

Inflammasomes are cytosolic pattern recognition receptors that recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) derived from invading pathogens and damaged tissues, respectively. Upon activation, the inflammasome forms a complex containing a receptor protein, an adaptor, and an effector to induce the autocleavage and activation of procaspase-1 ultimately culminating in the maturation and secretion of IL-1ß and IL-18 and pyroptosis. Inflammasome activation plays an important role in host immune responses to pathogen infections and tissue repair in response to cellular damage. The NLRP3 inflammasome is a well-characterized pattern recognition receptor and is well known for its critical role in the regulation of immunity and the development and progression of various inflammatory diseases. In this review, we summarize recent efforts to develop therapeutic applications targeting the NLRP3 inflammasome to cure and prevent chronic inflammatory diseases. This review extensively discusses NLRP3 inflammasome-related diseases and current development of small molecule inhibitors providing beneficial information on the design of therapeutic strategies for NLRP3 inflammasome-related diseases. Additionally, small molecule inhibitors are classified depending on direct or indirect targeting mechanism to describe the current status of the development of pharmacological inhibitors.

Skin Barrier Abnormalities and Immune Dysfunction in Atopic Dermatitis.

Atopic dermatitis (AD) is a common and relapsing skin disease that is characterized by skin barrier dysfunction, inflammation, and chronic pruritus. While AD was previously thought to occur primarily in children, increasing evidence suggests that AD is more common in adults than previously assumed. Accumulating evidence from experimental, genetic, and clinical studies indicates that AD expression is a precondition for the later development of other atopic diseases, such as asthma, food allergies, and allergic rhinitis. Although the exact mechanisms of the disease pathogenesis remain unclear, it is evident that both cutaneous barrier dysfunction and immune dysregulation are critical etiologies of AD pathology. This review explores recent findings on AD and the possible underlying mechanisms involved in its pathogenesis, which is characterized by dysregulation of immunological and skin barrier integrity and function, supporting the idea that AD is a systemic disease. These findings provide further insights for therapeutic developments aiming to repair the skin barrier and decrease inflammation.

Regulation of the NLRP3 Inflammasome by Post-Translational Modifications and Small Molecules.

Inflammation is a host protection mechanism that eliminates invasive pathogens from the body. However, chronic inflammation, which occurs repeatedly and continuously over a long period, can directly damage tissues and cause various inflammatory and autoimmune diseases. Pattern recognition receptors (PRRs) respond to exogenous infectious agents called pathogen-associated molecular patterns and endogenous danger signals called danger-associated molecular patterns. Among PRRs, recent advancements in studies of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome have established its significant contribution to the pathology of various inflammatory diseases, including metabolic disorders, immune diseases, cardiovascular diseases, and cancer. The regulation of NLRP3 activation is now considered to be important for the development of potential therapeutic strategies. To this end, there is a need to elucidate the regulatory mechanism of NLRP3 inflammasome activation by multiple signaling pathways, post-translational modifications, and cellular organelles. In this review, we discuss the intracellular signaling events, post-translational modifications, small molecules, and phytochemicals participating in the regulation of NLRP3 inflammasome activation. Understanding how intracellular events and small molecule inhibitors regulate NLRP3 inflammasome activation will provide crucial information for elucidating the associated host defense mechanism and the development of efficient therapeutic strategies for chronic diseases.

Luteolin 7-Sulfate Attenuates Melanin Synthesis through Inhibition of CREB- and MITF-Mediated Tyrosinase Expression.

Antioxidants with antimelanogenic activity are potentially useful for the attenuation of skin hyperpigmentation disorders. In a previous study, luteolin 7-sulfate isolated from Phyllospadix iwatensis Makino, a marine plant, was shown to inhibit cellular melanin synthesis. The aim of the present study was to examine its action mechanism, focusing on the regulation of tyrosinase (TYR) expression in cells. Cell-based assay was undertaken using murine melanoma B16-F10 cells and primary human epidermal melanocytes (HEMs). Luteolin 7-sulfate showed lower toxicity compared to luteolin in B16-F10 cells. At the non-toxic concentration ranges, luteolin 7-sulfate attenuated melanin synthesis, stimulated by α-melanocyte-stimulating hormone or forskolin. Luteolin 7-sulfate attenuated forskolin-induced microphthalmia-associated transcription factor (MITF) and TYR expressions at the mRNA and protein levels in B16-F10 cells. It also attenuated the phosphorylation of cAMP-responsive element binding protein (CREB) stimulated by forskolin. Luteolin 7-sulfate also attenuated melanin synthesis in primary HEMs. This study demonstrates that luteolin 7-sulfate attenuates TYR gene expression through the intervention of a CREB- and MITF-mediated signaling pathway, leading to the decreased melanin synthesis.

Ecklonia cava Extract and Dieckol Attenuate Cellular Lipid Peroxidation in Keratinocytes Exposed to PM10.

Airborne particulate matter can cause oxidative stress, inflammation, and premature skin aging. Marine plants such as Ecklonia cava Kjellman contain high amounts of polyphenolic antioxidants. The purpose of this study was to examine the antioxidative effects of E. cava extract in cultured keratinocytes exposed to airborne particulate matter with a diameter of <10 µm (PM10). After the exposure of cultured HaCaT keratinocytes to PM10 in the absence and presence of E. cava extract and its constituents, cell viability and cellular lipid peroxidation were assessed. The effects of eckol and dieckol on cellular lipid peroxidation and cytokine expression were examined in human epidermal keratinocytes exposed to PM10. The total phenolic content of E. cava extract was the highest among the 50 marine plant extracts examined. The exposure of HaCaT cells to PM10 decreased cell viability and increased lipid peroxidation. The PM10-induced cellular lipid peroxidation was attenuated by E. cava extract and its ethyl acetate fraction. Dieckol more effectively attenuated cellular lipid peroxidation than eckol in both HaCaT cells and human epidermal keratinocytes. Dieckol and eckol attenuated the expression of inflammatory cytokines such as tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1ß, IL-6, and IL-8 in human epidermal keratinocytes stimulated with PM10. This study suggested that the polyphenolic constituents of E. cava, such as dieckol, attenuated the oxidative and inflammatory reactions in skin cells exposed to airborne particulate matter.

Punicalagin and (-)-Epigallocatechin-3-Gallate Rescue Cell Viability and Attenuate Inflammatory Responses of Human Epidermal Keratinocytes Exposed to Airborne Particulate Matter PM10.

BACKGROUND/AIMS: Airborne particulate matter with a diameter of < 10 µm (PM10) causes oxidative damage, inflammation, and premature skin aging. In this study, we evaluated whether polyphenolic antioxidants attenuate the inflammatory responses of PM10-exposed keratinocytes. METHODS: Primary human epidermal keratinocytes were exposed in vitro to PM10 in the absence or presence of punicalagin and (-)-epigallocatechin-3-gallate (EGCG), which are the major polyphenolic antioxidants found in pomegranate and green tea, respectively. Assays were performed to determine cell viability, production of reactive oxygen species (ROS), and expression of NADPH oxidases (NOX), proinflammatory cytokines, and matrix metalloproteinase (MMP)-1. RESULTS: PM10 decreased cell viability and increased ROS production in a dose-dependent manner. It also increased the expression levels of NOX-1, NOX-2, tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6, IL-8, and MMP-1. Punicalagin was not cytotoxic up to 300 µM, and (-)-EGCG was cytotoxic above 30 µM, respectively. Further, punicalagin (3-30 µM) and EGCG (3-10 µM) rescued the viability of PM10-exposed cells. They also attenuated ROS production and the expression of NOX-1, NOX-2, TNF-α, IL-1ß, IL-6, IL-8, and MMP-1 stimulated by PM10. CONCLUSIONS: This study demonstrates that polyphenolic antioxidants, such as punicalagin and (-)-EGCG, rescue keratinocyte viability and attenuate the inflammatory responses of these cells due to airborne particles.

Anti-Inflammatory Effects of Pomegranate Peel Extract in THP-1 Cells Exposed to Particulate Matter PM10.

Epidemiological and experimental evidence support health risks associated with the exposure to airborne particulate matter with a diameter of <10 µM (PM10). PM10 stimulates the production of reactive oxygen species (ROS) and inflammatory mediators. Thus, we assumed that natural antioxidants might provide health benefits attenuating hazardous effects of PM10. In the present study, we examined the effects of pomegranate peel extract (PPE) on THP-1 monocytic cells exposed to PM10. PM10 induced cytotoxicity and the production of ROS. It also increased the expression and secretion of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and monocyte chemoattractant protein-1 (MCP-1), and cell adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). PPE at 10-100 µg mL(-1) attenuated the production of ROS and the expression of TNF-α, IL-1ß, MCP-1, and ICAM-1, but not VCAM-1, in THP-1 cells stimulated by PM10 (100 µg mL(-1)). PPE also attenuated the adhesion of PM10-stimulated THP-1 cells to EA.hy926 endothelial cells. PPE constituents, punicalagin and ellagic acid, attenuated PM10-induced monocyte adhesion to endothelial cells, and punicalagin was less cytotoxic compared to ellagic acid. The present study suggests that PPE and punicalagin may be useful in alleviating inflammatory reactions due to particulate matter.

Anti-melanogenic effects of resveratryl triglycolate, a novel hybrid compound derived by esterification of resveratrol with glycolic acid.

Resveratrol is known to inhibit cellular melanin synthesis by multiple mechanisms. Glycolic acid (GA) is used in skin care products for its excellent skin penetration. The purpose of this study was to examine the anti-melanogenic effects of resveratryl triglycolate (RTG), a novel hybrid compound of resveratrol and GA, in comparison with resveratrol, GA, resveratryl triacetate (RTA) and arbutin. Resveratrol, RTG, and RTA inhibited the catalytic activity human tyrosinase (TYR) more potently than arbutin or GA did. Their cytotoxic and anti-melanogenic effects were examined using murine melanoma B16/F10 cells and human epidermal melanocytes (HEMs). The cytotoxicity of RTG was similar to that of resveratrol and RTA. RTG at 3-10 µM decreased melanin levels and cellular TYR activities in α-melanocyte-stimulating hormone-stimulated B16/F10 cells, and L-tyrosine-stimulated HEMs. RTG also suppressed mRNA and protein expression of TYR, tyrosinase-related protein 1, L-3,4-dihydroxyphenylalanine chrome tautomerase, and microphthalmia-associated transcription factor (MITF) in HEMs stimulated with L-tyrosine. This study suggests that, like resveratrol and RTA, RTG can attenuate cellular melanin synthesis effectively through the suppression of MITF-dependent expression of melanogenic enzymes and the inhibition of catalytic activity of TYR enzyme. RTG therefore has potential for use as a cosmeceutical ingredient for skin whitening.

Scutellaria radix Extract as a Natural UV Protectant for Human Skin.

Ultraviolet (UV) radiation induces oxidative injury and inflammation in human skin. Scutellaria radix (SR, the root of Scutellaria baicalensis Georgi) contains flavonoids with high UV absorptivity and antioxidant properties. The purpose of this study was to examine the potential use of SR extract as an additive in cosmetic products for UV protection. SR extract and its butanol (BuOH) fraction strongly absorbed UV radiation and displayed free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radials and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals. They also attenuated the UV-induced death of HaCaT cells. Sunscreen creams, with or without supplementation of SR extract BuOH fraction, were tested in vivo in human trials to evaluate potential skin irritation and determine the sun protection factor (SPF). Both sunscreen creams induced no skin irritation. A sunscreen cream containing 24% ZnO showed an SPF value of 17.8, and it increased to 22.7 when supplemented with 5% SR extract BuOH fraction. This study suggests that SR-derived materials are useful as safe cosmetic additives that provide UV protection.

Ascorbyl coumarates as multifunctional cosmeceutical agents that inhibit melanogenesis and enhance collagen synthesis.

L-Ascorbic acid (AA) and p-coumaric acid (p-CA) are naturally occurring antioxidants that are known to enhance collagen synthesis and inhibit melanin synthesis, respectively. The purpose of this study was to examine hybrid compounds between AA and p-CA as multifunctional cosmeceutical agents. Ascorbyl 3-p-coumarate (A-3-p-C), ascorbyl 2-p-coumarate (A-2-p-C), and their parent compounds were tested for their effects on cellular melanin synthesis and collagen synthesis. At 100 µM, A-3-p-C and A-2-p-C decreased melanin content of human dermal melanocytes stimulated by L-tyrosine, by 65 and 59%, respectively, compared to 11% inhibition of AA and 70% inhibition of p-CA. A-3-p-C and A-2-p-C were less effective than p-CA but more effective than AA at inhibiting tyrosinase activity. A-3-p-C and A-2-p-C were more effective than p-CA at inhibiting the autoxidation of L-3,4-dihydroxyphenylalanine. At 100-300 µM, A-3-p-C and A-2-p-C augmented collagen release from human dermal fibroblasts by 120-144% and 125-191%, respectively, compared to 126-133% increase of AA and 120-146% increase of p-CA. They increased procollagen type I C-peptide release (A-3-p-C, and A-2-p-C) like AA, and decreased matrix metalloproteinase 1 level (A-2-p-C) like p-CA, implicating that they might regulate collagen metabolism by multiple mechanisms. This study suggests that A-3-p-C and A-2-p-C could be used as multifunctional cosmeceutical agents for the attenuation of certain aspects of skin aging.

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts.

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging.

A study of the human skin-whitening effects of resveratryl triacetate.

Resveratrol has a variety of bioactivities that include its anti-melanogenic effects, but its use in cosmetics has been challenging partly because of its chemical instability. Resveratryl triacetate (RTA) is a prodrug that can enhance stability. The purpose of this study was to examine the skin safety and whitening effects of RTA in human subjects. The primary skin irritation potentials of RTA and resveratrol were tested at 0.1 and 0.5 % on human subjects. Resveratrol at a concentration of 0.5 % induced weak skin irritation, whereas RTA did not induce any skin responses. The skin-whitening efficacy of a cosmetic formulation containing 0.4 % RTA was evaluated in two different test models. In the artificial tanning model, the test product and the control product were applied twice daily to the skin of the forearms of 22 human subjects after pigmentation induction by ultraviolet irradiation. Applying the test and the control products to the artificial tanning model for 8 weeks increased the individual topology angles (ITA°) by 17.06 and 13.81 %, respectively, a difference that was statistically significant (p < 0.05). In the hyperpigmentation model, the test product and the control product were applied twice daily to the faces of 21 human subjects. The averaged intensity of the hyperpigmented spots decreased by 2.67 % in the test group and 1.46 % in the control group, a difference that was statistically significant (p < 0.05). Therefore, RTA incorporated into cosmetic formulations can whiten human skin without inducing skin irritation.

MicroRNA-382 induced by HIF-1α is an angiogenic miR targeting the tumor suppressor phosphatase and tensin homolog.

Recent studies have revealed that microRNAs (miRs) play important roles in the regulation of angiogenesis. In this study, we have characterized miR-382 upregulation by hypoxia and the functional relevance of miR-382 in tumor angiogenesis. miRs induced by hypoxia in MKN1 human gastric cancer cells were investigated using miRNA microarrays. We selected miR-382 and found that the expression of miR-382 was regulated by HIF-1α. Conditioned media (CM) from MKN1 cells transfected with a miR-382 inhibitor (antagomiR-382) under hypoxic conditions significantly decreased vascular endothelial cell (EC) proliferation, migration and tube formation. Algorithmic programs (Target Scan, miRanda and cbio) predicted that phosphatase and tensin homolog (PTEN) is a target gene of miR-382. Deletion of miR382-binding sequences in the PTEN mRNA 3'-untranslated region (UTR) diminished the luciferase reporter activity. Subsequent study showed that the overexpression of miR-382 or antagomiR-382 down- or upregulated PTEN and its downstream target AKT/mTOR signaling pathway, indicating that PTEN is a functional target gene of miR-382. In addition, PTEN inhibited miR-382-induced in vitro and in vivo angiogenesis as well as VEGF secretion, and the inhibition of miR-382 expression reduced xenograft tumor growth and microvessel density in tumors. Taken together, these results suggest that miR-382 induced by hypoxia promotes angiogenesis and acts as an angiogenic oncogene by repressing PTEN.

Gardenia jasminoides Extract Attenuates the UVB-Induced Expressions of Cytokines in Keratinocytes and Indirectly Inhibits Matrix Metalloproteinase-1 Expression in Human Dermal Fibroblasts.

Ultraviolet radiation (UV) is a major cause of photoaging, which also involves inflammatory cytokines and matrix metalloproteinases (MMP). The present study was undertaken to examine the UVB-protecting effects of yellow-colored plant extracts in cell-based assays. HaCaT keratinocytes were exposed to UVB in the absence or presence of plant extracts, and resulting changes in cell viability and inflammatory cytokine expression were measured. Of the plant extracts tested, Gardenia jasminoides extract showed the lowest cytotoxicity and dose-dependently enhanced the viabilities of UVB-exposed cells. Gardenia jasminoides extract also attenuated the mRNA expressions of interleukin-1 ß (IL-1 ß ) and tumor necrosis factor- α (TNF- α ) in HaCaT cells stimulated by UVB. Conditioned medium from UVB-exposed HaCaT cells was observed to stimulate MMP-1 protein expression in human dermal fibroblasts, and this effect was much smaller for the conditioned medium of HaCaT cells exposed to UVB in the presence of Gardenia jasminoides extract. Gardenia jasminoides extract also exhibited antioxidative and antiapoptotic effects in HaCaT cells exposed to UVB. These results indicated that UVB-induced injury and inflammatory responses of skin cells can be attenuated by yellow-colored plant extracts, such as Gardenia jasminoides extract.