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Supplementary Figure 2 from Activation of Hypoxia-Inducible Factor-1α Is Necessary for Lysophosphatidic Acid–Induced Vascular Endothelial Growth Factor Expression

Supplementary Figure 3 from Activation of Hypoxia-Inducible Factor-1α Is Necessary for Lysophosphatidic Acid–Induced Vascular Endothelial Growth Factor Expression

Purpose: Lysophosphatidic acid (LPA) plays an important role in mediating cell proliferation, survival, and tumor invasion and angiogenesis. This bioactive phospholipid at the concentration in ascitic fluid stimulates the growth of malignant ovarian tumors by increasing the expression of vascular endothelial growth factor (VEGF). In the present study, we investigated whether LPA activates hypoxia inducible factor-1 (HIF-1), a key transcriptional complex in tumor progression and metastasis, thereby increasing the expression of VEGF.Experimental Design: Immunoblotting, reverse transcription-PCR, ELISA, immunofluorescence, and chromatin immunoprecipitation assay were used to examine the expression of VEGF and HIF-1α in various cancer cells. Specific HIF-1α small interfering RNA was transfected to various cancer cells to determine the role of HIF-1α in LPA-induced VEGF expression.Results: LPA induced expressions of VEGF and HIF-1α in OVCAR-3, CAOV-3, PC-3, and SK-Hep1 cells but not in SKOV-3 and Hep-3B cells. In OVCAR-3 and PC-3 cells, the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin/p70S6K and p42/p44 mitogen-activated protein kinase pathways were required for LPA-induced HIF-1α and VEGF expressions, whereas only the phosphoinositide 3-kinase/mammalian target of rapamycin/p70S6K pathway was important in SK-Hep1 cells. Immunofluorescence microscopy assay showed translocation of HIF-1α to nucleus by LPA, and chromatin immunoprecipitation assay revealed the binding of HIF-1α to the promoter of VEGF by LPA. Importantly, we found that small interfering RNA–induced reduction of HIF-1α expression significantly attenuated VEGF expression by LPA.Conclusions: Our results show for the first time that LPA induces VEGF via HIF-1α activation and reveal a critical role of HIF-1α in LPA-induced cancer cell proliferation and angiogenesis.

Protein arginine methyltransferase 7 (PRMT7) regulates various cellular responses, including gene expression, cell migration, stress responses, and stemness. In this study, we investigated the biological role of PRMT7 in cell cycle progression and DNA damage response (DDR) by inhibiting PRMT7 activity with either SGC8158 treatment or its specific siRNA transfection. Suppression of PRMT7 caused cell cycle arrest at the G1 phase, resulting from the stabilization and subsequent accumulation of p21 protein. In addition, PRMT7 activity is closely associated with DNA repair pathways, including both homologous recombination and non-homologous end-joining. Interestingly, SGC8158, in combination with doxorubicin, led to a synergistic increase in both DNA damage and cytotoxicity in MCF7 cells. Taken together, our data demonstrate that PRMT7 is a critical modulator of cell growth and DDR, indicating that it is a promising target for cancer treatment.

The skin acts as a mechanical barrier that protects the body from the exterior environment, and skin barrier function is attributed to the stratum corneum (SC), which is composed of keratinocytes and skin lipids. Skin barrier homeostasis is maintained by a delicate balance between the differentiation and exfoliation of keratinocytes, and keratinocyte desquamation is regulated by members of the serine protease kalikrein (KLK) family and their endogenous inhibitor SPINK5/LEKTI (serine protease inhibitor Kazal type 5/lympho-epithelial Kazal-type-related inhibitor). Furthermore, SPINK5/LEKTI deficiency is involved in impaired skin barrier function caused by KLK over-activation. We sought to determine whether increased SPINK5/LEKTI expression ameliorates atopic dermatitis (AD) by strengthening skin barrier function using the ethanol extract of Lobelia chinensis (LCE) and its active compound, diosmetin, by treating human keratinocytes with UVB and using a DNCB-induced murine model of atopic dermatitis. LCE or diosmetin dose-dependently increased the transcriptional activation of SPINK5 promoter and prevented DNCB-induced skin barrier damage by modulating events downstream of SPINK5, that is, KLK, PAR2 (protease activated receptor 2), and TSLP (thymic stromal lymphopoietin). LCE or diosmetin normalized immune response in DNCB treated SKH-1 hairless mice as determined by reductions in serum immunoglobulin E and interleukin-4 levels and numbers of lesion-infiltrating mast cells. Our results suggest that LCE and diosmetin are good candidates for the treatment of skin barrier-disrupting diseases such as Netherton syndrome or AD, and that they do so by regulating SPINK5/LEKTI.

The activation and degranulation of immune cells play a pivotal role in allergic inflammation, a pathological condition that includes anaphylaxis, pruritus, and allergic march-related diseases. In this study, trifuhalol A, a phlorotannin isolated from Agarum cribrosum, inhibited the degranulation of immune cells and the biosynthesis of IL-33 and IgE in differentiated B cells and keratinocytes, respectively. Additionally, trifuhalol A suppressed the IL-33 and IgE-mediated activation of RBL-2H3 cells through the regulation of the TAK1 and MK2 pathways. Hence, the effect of trifuhalol A on allergic inflammation was evaluated using a Compound 48/80-induced systemic anaphylaxis mouse model and a house dust mite (HDM)-induced atopic dermatitis (AD) mouse model. Trifuhalol A alleviated anaphylactic death and pruritus, which appeared as an early-phase reaction to allergic inflammation in the Compound 48/80-induced systemic anaphylaxis model. In addition, trifuhalol A improved symptoms such as itching, edema, erythema, and hyperkeratinization in HDM-induced AD mice as a late-phase reaction. Moreover, the expression of IL-33 and thymic stromal lymphopoietin, inflammatory cytokines secreted from activated keratinocytes, was significantly reduced by trifuhalol A administration, resulting in the reduced infiltration of immune cells into the skin and a reduction in the blood levels of IgE and IL-4. In summarizing the above results, these results confirm that trifuhalol A is a potential therapeutic candidate for the regulation of allergic inflammation.

Protein methylation, a post-translational modification (PTM), is observed in a wide variety of cell types from prokaryotes to eukaryotes. With recent and rapid advancements in epigenetic research, the importance of protein methylation has been highlighted. The methylation of histone proteins that contributes to the epigenetic histone code is not only dynamic but is also finely controlled by histone methyltransferases and demethylases, which are essential for the transcriptional regulation of genes. In addition, many nonhistone proteins are methylated, and these modifications govern a variety of cellular functions, including RNA processing, translation, signal transduction, DNA damage response, and the cell cycle. Recently, the importance of protein arginine methylation, especially in cell cycle regulation and DNA repair processes, has been noted. Since the dysregulation of protein arginine methylation is closely associated with cancer development, protein arginine methyltransferases (PRMTs) have garnered significant interest as novel targets for anticancer drug development. Indeed, several PRMT inhibitors are in phase 1/2 clinical trials. In this review, we discuss the biological functions of PRMTs in cancer and the current development status of PRMT inhibitors in cancer therapy., Cancer therapy: Exploring possible enzyme targets Understanding the roles, regulation and downstream targets of a family of enzymes involved in cancer development could improve future therapies. Yong Kee Kim at Sookmyung Women’s University, Seoul, South Korea, and co-workers reviewed current knowledge of protein arginine methyltransferases (PRMTs), their influence on cell cycle regulation and DNA damage responses in cancer, and their potential as anti-cancer targets. PRMTs act as catalysts in modification of the amino acid arginine. This process is critical to healthy cellular function, and its disruption is linked to cancer development. The overexpression of certain PRMTs is a driving factor in cancer tumor growth, metastasis and poor prognosis. PRMT inhibitors are showing promise in clinical trials for B-cell lymphoma and various solid tumors. Combined therapies targeting more than one PRMT could prove valuable.

We investigated the role of TONSL, a mediator of homologous recombination repair (HRR), in stalled replication fork double-strand breaks (DSBs) in cancer. Publicly available clinical data (tumors from the ovary, breast, stomach and lung) were analyzed through KM Plotter, cBioPortal and Qomics. Cancer stem cell (CSC)-enriched cultures and bulk/general mixed cell cultures (BCCs) with RNAi were employed to determine the effect of TONSL loss in cancer cell lines from the ovary, breast, stomach, lung, colon and brain. Limited dilution assays and ALDH assays were used to quantify the loss of CSCs. Western blotting and cell-based homologous recombination assays were used to identify DNA damage derived from TONSL loss. TONSL was expressed at higher levels in cancer tissues than in normal tissues, and higher expression was an unfavorable prognostic marker for lung, stomach, breast and ovarian cancers. Higher expression of TONSL is partly associated with the coamplification of TONSL and MYC, suggesting its oncogenic role. The suppression of TONSL using RNAi revealed that it is required in the survival of CSCs in cancer cells, while BCCs could frequently survive without TONSL. TONSL dependency occurs through accumulated DNA damage-induced senescence and apoptosis in TONSL-suppressed CSCs. The expression of several other major mediators of HRR was also associated with worse prognosis, whereas the expression of error-prone nonhomologous end joining molecules was associated with better survival in lung adenocarcinoma. Collectively, these results suggest that TONSL-mediated HRR at the replication fork is critical for CSC survival; targeting TONSL may lead to the effective eradication of CSCs.

Naturally derived diosmetin and its glycoside diosmin are known to be effective in treating inflammatory disease. This study was performed to determine whether diosmin and diosmetin have the effect of improving atopic dermatitis in a 2,4-dinitrochlorobenzen (DNCB)-induced atopic dermatitis (AD) model. DNCB was used to establish AD model in hairless mice. Skin moisture, serum immunoglobulin E (IgE), interleukin 4 (IL-4), and histological analysis were performed to measure the effectiveness of diosmin and diosmetine to improve AD. IL-4 levels were also measured in RBL-2H3 cells. Administration of diosmetin or diosmin orally inhibited the progress of DNCB-induced AD-like lesions in murine models by inhibiting transdermal water loss (TEWL) and increasing skin hydration. Diosmetin or diosmin treatment also reduced IgE and IL-4 levels in AD-induced hairless mouse serum samples. However, in the in vitro assay, only diosmetin, not diosmin, reduced the expression level of IL-4 mRNA in RBL-2H3 cells. Diosmin and diosmetine alleviated the altered epidermal thickness and immune cell infiltration in AD. Diosmin is considered effective in the cure of AD and skin inflammatory diseases by being converted into diosmetin in the body by pharmacokinetic metabolism. Thus, oral administration of diosmetin and diosmin might be a useful agent for the treatment of AD and cutaneous inflammatory diseases.

PRMT5 participates in various cellular processes, including transcription regulation, signal transduction, mRNA splicing, and DNA repair; however, its mechanism of regulation is poorly understood. Here, we demonstrate that PRMT5 is phosphorylated at residue Y324 by Src kinase, a negative regulator of its activity. Either phosphorylation or substitution of the Y324 residue suppresses PRMT5 activity by preventing its binding with the methyl donor S-adenosyl-L-methionine. Additionally, we show that PRMT5 activity is associated with non-homologous end joining (NHEJ) repair by methylating and stabilizing p53-binding protein 1 (53BP1), which promotes cellular survival after DNA damage. Src-mediated phosphorylation of PRMT5 and the subsequent inhibition of its activity during the DNA damage process blocks NHEJ repair, leading to apoptotic cell death. Altogether, our findings suggest that PRMT5 regulates DNA repair through Src-mediated Y324 phosphorylation in response to DNA damage., Hwang et al. show that the activity of PRMT5 methyltransferase is regulated by Src kinase-mediated phosphorylation at Y324 in response to DNA damage. They also show that PRMT5 participates in NHEJ repair by regulating 53BP1 protein levels and is critical for cellular survival after DNA damage.

Angiotensin II (AngII) has potent cardiac hypertrophic effects mediated through activation of hypertrophic signaling like Wnt/b-Catenin signaling. In the current study, we examined the role of protein arginine methyltransferase 7 (PRMT7) in cardiac function. PRMT7 was greatly decreased in hypertrophic hearts chronically infused with AngII and cardiomyocytes treated with AngII. PRMT7 depletion in rat cardiomyocytes resulted in hypertrophic responses. Consistently, mice lacking PRMT7 exhibited displayed the cardiac hypertrophy and fibrosis. PRMT7 overexpression abrogated the cellular hypertrophy elicited by AngII, while PRMT7 depletion exacerbated the hypertrophic response caused by AngII. Similar with AngII treatment, the cardiac transcriptome analysis of PRMT7-deficient hearts revealed the alteration in gene expression profile related to Wnt signaling pathway. Inhibition of PRMT7 by gene deletion or an inhibitor treatment enhanced the activity of b-Catenin. PRMT7 deficiency decreases symmetric dimethylation of b-Catenin. Mechanistic studies reveal that methylation of arginine residue 93 in b-Catenin decreases the activity of b-Catenin. Taken together, our data suggest that PRMT7 is important for normal cardiac function through suppression of b-Catenin activity.

Background: As a process of aging, skeletal muscle mass and function gradually decrease. It is reported that ginsenoside Rb1 and Rb2 play a role as AMP-activated protein kinase activator, resulting in regulating glucose homeostasis, and Rb1 reduces oxidative stress in aged skeletal muscles through activating the phosphatidylinositol 3-kinase/Akt/Nrf2 pathway. We examined the effects of Rb1 and Rb2 on differentiation of the muscle stem cells and myotube formation. Methods: C2C12 myoblasts treated with Rb1 and/or Rb2 were differentiated and induced to myotube formation, followed by immunoblotting for myogenic marker proteins, such as myosin heavy chain, MyoD, and myogenin, or immunostaining for myosin heavy chain or immunoprecipitation analysis for heterodimerization of MyoD/E-proteins. Results: Rb1 and Rb2 enhanced myoblast differentiation through accelerating MyoD/E-protein heterodimerization and increased myotube hypertrophy, accompanied by activation of Akt/mammalian target of rapamycin signaling. In addition, Rb1 and Rb2 induced the MyoD-mediated transdifferentiation of the rhabdomyosarcoma cells into myoblasts. Furthermore, co-treatment with Rb1 and Rb2 had synergistically enhanced myoblast differentiation through Akt activation. Conclusion: Rb1 and Rb2 upregulate myotube growth and myogenic differentiation through activating Akt/mammalian target of rapamycin signaling and inducing myogenic conversion of fibroblasts. Thus, our first finding indicates that Rb1 and Rb2 have strong potential as a helpful remedy to prevent and treat muscle atrophy, such as age-related muscular dystrophy. Keywords: Akt/mTOR signaling, Hypertrophy, Myoblast differentiation, Rb1, Rb2

Background and Purpose: The success of cancer chemotherapy is limited by multidrug resistance (MDR), which is mainly caused by P-glycoprotein (P-gp) overexpression. In the present study, we describe a novel microtubule inhibitor, 5-(N-methylmaleimid-3-yl)-chromone (SPC-160002), that can be used to overcome MDR. Experimental Approach: Key Results: A synthetic chromone derivative, SPC-160002, showed a broad spectrum of anti-proliferative effects on various human cancer cells without affecting P-gp expression and its drug efflux function. Treatment with SPC-160002 arrested the cell cycle at the M phase, as evidenced using fluorescence-activated cell sorting analysis, and increased the levels of mitotic marker proteins, including cyclin B, pS10-H3, and chromosomal passenger complex. This mitotic arrest by SPC-160002 was mediated by promoting and stabilizing microtubule polymerization, similar to the mechanism observed in case of taxane-based drugs. Furthermore, SPC-160002 suppressed the growth and sphere-forming activity of cancer stem cells. Conclusion and Implications: Our data herein strongly suggest that SPC-160002, a novel microtubule inhibitor, can be used to overcome MDR and can serve as an attractive candidate for anticancer drugs.

Multidrug resistance (MDR), which is a significant impediment to the success of cancer chemotherapy, is attributable to various defensive mechanisms in cancer. Initially, overexpression of ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp) was considered the most important mechanism for drug resistance; hence, many investigators for a long time focused on the development of specific ABC transporter inhibitors. However, to date their efforts have failed to develop a clinically applicable drug, leaving only a number of problems. The concept of cancer stem cells (CSCs) has provided new directions for both cancer and MDR research. MDR is known to be one of the most important features of CSCs and thus plays a crucial role in cancer recurrence and exacerbation. Therefore, in recent years, research targeting CSCs has been increasing rapidly in search of an effective cancer treatment. Here, we review the drugs that have been studied and developed to overcome MDR and CSCs, and discuss the limitations and future perspectives.

The kinase Aurora B forms the chromosomal passenger complex (CPC) together with Borealin, INCENP, and Survivin to mediate chromosome condensation, the correction of erroneous spindle-kinetochore attachments, and cytokinesis. Phosphorylation of histone H3 Thr3 by Haspin kinase and of histone H2A Thr120 by Bub1 concentrates the CPC at the centromere. However, how the CPC is recruited to chromosome arms upon mitotic entry is unknown. Here, we show that asymmetric dimethylation at Arg2 on histone H3 (H3R2me2a) by protein arginine methyltransferase 6 (PRMT6) recruits the CPC to chromosome arms and facilitates histone H3S10 phosphorylation by Aurora B for chromosome condensation. Furthermore, in vitro assays show that Aurora B preferentially binds to the H3 peptide containing H3R2me2a and phosphorylates H3S10. Our findings indicate that the long-awaited key histone mark for CPC recruitment onto mitotic chromosomes is H3R2me2a, which is indispensable for maintaining appropriate CPC levels in dynamic translocation throughout mitosis., The proteins of the chromosomal passenger complex help chromosomes condense before cell division, but how this complex arrives at chromosomes was not known. Here the authors show that PRMT6 methylates histone H3 to recruit the chromosomal passenger complex.

To investigate the potential effects of acorn shells on atopic dermatitis (AD), we utilized oxazolone (OX)- or 2,4-dinitrochlorobenzene (DNCB)-induced AD-like lesion mouse models. Our research demonstrates that Acorn shell extract (ASE) improved the progression of AD-like lesions, including swelling, which were induced by oxazolone on Balb/c mouse ears. Additionally, ASE significantly decreased the ear thickness (OX: 0.42 ± 0.01 mm, OX-ASE: 0.32 ± 0.02 mm) and epidermal thickness (OX: 75.3 ± 32.6 µm, OX-ASE: 46.1 ± 13.4 µm). The continuous DNCB-induced AD mouse model in SKH-1 hairless mice demonstrated that ASE improved AD-like symptoms, including the recovery of skin barrier dysfunction, Immunoglobulin E hyperproduction (DNCB: 340.1 ± 66.8 ng/mL, DNCB-ASE: 234.8 ± 32.9 ng/mL) and an increase in epidermal thickness (DNCB: 96.4 ± 21.9 µm, DNCB-ASE: 52.4 ± 16.3 µm). In addition, we found that ASE suppressed the levels of AD-involved cytokines, such as Tumor Necrosis Factor α, IL-1β, IL-25 and IL-33 in both animal models. Furthermore, gallic acid and ellagic acid isolated from ASE suppressed β-hexosaminidase release and IL-4 expression in RBL-2H3 cells. The acorn shell and its active phytochemicals have potential as a new remedy for the improvement of atopic dermatitis and other inflammatory diseases.

Preservation of muscle stem cell function is critical for muscle homeostasis and the regenerative capacity of stem cells declines with age, leading to muscle loss. Previously, daidzein, a natural isoflavone from Leguminosae, has been shown to prevent TNF-α-induced muscle atrophy. However, the molecular mechanisms of daidzein in these processes are currently unknown. In this study, we demonstrate a positive effect of black soybean extract (BS Ext) and daidzein on myoblast differentiation and myotube growth. Daidzein prevents dexamethasone-induced myotube atrophy through Akt activation. The promyogenic effect of BS Ext and daidzein is mediated through two promyogenic kinases, Akt and p38MAPK that in turn activates a key myogenic transcription factor MyoD. Additionally, BS Ext and daidzein promote myotube growth through Akt/mTOR/S6K pathway. Finally, daidzein augments MyoD-dependent myogenic conversion of mouse embryonic fibroblasts. Taken together, our data suggest that daidzein promotes myogenic differentiation and myotube hypertrophy through p38 and Akt/mTOR/S6K pathway.

Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) is a flavonoid compound exhibiting several beneficial biological activities, including neuroprotection, anti-cancer, antinociception, chondroprotection, anti-oxidation, and anti-inflammation. Our previous study demonstrated that eupatilin specifically activates peroxisome proliferator-activated receptor alpha (PPARα) through direct binding. The PPAR subfamily includes ligand-dependent transcription factors that consist of three isotypes: PPARα, PPARβ/δ, and PPARγ. All isotypes are involved in inflammation, epidermal proliferation/differentiation and skin barrier function. Among them, PPARα regulates lipid and glucose metabolism and skin homeostasis. In this study, we confirm that the ability of eupatilin as a PPARα activator significantly inhibited tumor necrosis factor-alpha (TNFα)-induced matrix metalloproteinase (MMP)-2/-9 expression and proteolytic activity in HaCaT human epidermal keratinocytes. Furthermore, we found that eupatilin subsequently suppressed IκBα phosphorylation, blocked NF-κB p65 nuclear translocation and down-regulated MAPK/AP-1 signaling via PPARα activation. Taken together, our data suggest that eupatilin inhibits TNFα-induced MMP-2/-9 expression by suppressing NF-κB and MAPK⁄AP-1 pathways via PPARα. Our findings suggest the usefulness of eupatilin for preventing skin aging.

Background Ginsenoside Rg1 belongs to protopanaxatriol-type ginsenosides and has diverse pharmacological activities. In this report, we investigated whether Rg1 could upregulate muscular stem cell differentiation and muscle growth. Methods C2C12 myoblasts, MyoD-transfected 10T1/2 embryonic fibroblasts, and HEK293T cells were treated with Rg1 and differentiated for 2 d, subjected to immunoblotting, immunocytochemistry, or immunoprecipitation. Results Rg1 activated promyogenic kinases, p38MAPK (mitogen-activated protein kinase) and Akt signaling, that in turn promote the heterodimerization with MyoD and E proteins, resulting in enhancing myogenic differentiation. Through the activation of Akt/mammalian target of rapamycin pathway, Rg1 induced myotube growth and prevented dexamethasone-induced myotube atrophy. Furthermore, Rg1 increased MyoD-dependent myogenic conversion of fibroblast. Conclusion Rg1 upregulates promyogenic kinases, especially Akt, resulting in improvement of myoblast differentiation and myotube growth.

In this study, we aimed to demonstrate the antidiabetic potential of (E)-N-(4-(3-(5-bromo-4-hydroxy-2-methoxyphenyl)acryloyl) phenyl)-4-tert-butylbenzamide (SN158) through peroxisome proliferator-activated receptor (PPAR)-α/γ dual activation. SN158 interacted with both PPARα and PPARγ, and increased their transcriptional activities. Simultaneously, SN158 treatment led to an increase in adipogenic differentiation of 3T3-L1 preadipocytes and fatty acid oxidation in hepatocytes. In addition, glucose uptake in myotubes was significantly increased by SN158 treatment. Finally, SN158 significantly lowered the plasma levels of glucose, triglycerides, and free fatty acids in ob/ob mice without severe weight gain and hepatomegaly. These results suggest that SN158 can be useful as a potential therapeutic agent against type 2 diabetes and related metabolic disorders by alleviating glucose and lipid abnormalities.

Background The skin acts as a barrier to protect organisms against harmful exogenous agents. Compound K (CK) is an active metabolite of ginsenoside Rb1, Rb2 and Rc, and researchers have focused on its skin protective efficacy. In this study, we hypothesized that increased expression of the serine protease inhibitor Kazal type-5 (SPINK5) may improve skin barrier function. Methods We screened several ginsenosides to increase SPINK5 gene promoter activity using a transactivation assay and found that CK can increase SPINK5 expression. To investigate the protective effect of CK on the skin barrier, RT-PCR and Western blotting were performed to investigate the expression levels of SPINK5, kallikrein 5 (KLK5), KLK7 and PAR2 in UVB-irradiated HaCaT cells. Measurement of transepidermal water loss (TEWL) and histological changes associated with the skin barrier were performed in a UVB-irradiated mouse model and a 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis–like model. Results CK treatment increased the expression of SPINK5 and decreased the expression of its downstream genes, such as KLKs and PAR2. In the UVB-irradiated mouse model and the DNCB-induced atopic dermatitis model, CK restored increased TEWL and decreased hydration and epidermal hyperplasia. In addition, CK normalized the reduced SPINK5 expression caused by UVB or DNCB, thereby restoring the expression of the proteins involved in desquamation to a level similar to normal. Conclusions Our data showed that CK contributes to improving skin-barrier function in UVB-irradiated and DNCB-induced atopic dermatitis–like models through SPINK5. These results suggest that therapeutic attempts with CK might be useful in treating barrier-disrupted diseases.

Previous reports have shown that PPARβ/δ agonists ameliorate insulin resistance associated with type 2 diabetes mellitus (T2DM). To determine the role of PPARβ/δ in tumor necrosis factor α (TNFα)-mediated insulin resistance, we investigated expression levels of adiponectin and insulin receptor (IR) in response to treatment with the PPARβ/δ agonist GW501516 with or without TNFα, a proinflammatory cytokine, in differentiated 3T3-L1 adipocytes. GW501516 induced adipocyte differentiation and the expression of adiponectin in a dose-dependent manner in differentiated adipocytes. TNFα treatment reduced adiponectin expression at the end of differentiation. This effect was reversed by GW501516 co-treatment with TNFα. TNFα treatment decreased adipogenic marker genes such as PPARγ, aP2, resistin, and GLUT4, and GW501516 reversed the effects of TNFα. GW501516 treatment increased the expression of insulin receptor and inhibited TNFα-mediated repression of insulin receptor. Our results showed that GW501516 abrogated TNFα-induced insulin resistance. In summary, our study demonstrated that the PPARβ/δ agonist, GW501516 reversed TNFα-induced decreases in adipocyte differentiation and adiponectin expression, and improved insulin sensitivity by increasing the expression of insulin receptor. Therefore, PPARδ may be a promising therapeutic target for treatment of insulin resistance in patients with T2DM.

Muscle regeneration is a coordinated process that involves proliferation and differentiation of muscle progenitor cells. Activation of MyoD is a key event in myogenic differentiation, which is regulated by p38 mitogen-activated protein kinases (MAPK). In a screen of natural compounds for the enhancement of MyoD activity, dehydrocorydaline (DHC) from the Corydalis tuber was identified. Treatment of C2C12 myoblasts with DHC increased the expression levels of muscle-specific proteins, including MyoD, myogenin and myosin heavy chain. In addition, C2C12 myoblasts exhibited enhanced multinucleated myotube formation without any cytotoxicity. Treatment with DHC elevated p38 MAPK activation and the interaction of MyoD with an E protein, which is likely to result in activation of MyoD and promotion of myoblast differentiation. Furthermore, defects in differentiation-induced p38 MAPK activation and myoblast differentiation induced by depletion of the promyogenic receptor protein Cdo in C2C12 myoblasts were restored by DHC treatment. In conclusion, these results indicated that DHC stimulates p38 MAPK activation, which can enhance heterodimerization of MyoD and E proteins, thus resulting in MyoD activation and myoblast differentiation. These findings suggested that DHC may be considered a potential therapeutic compound for the improvement of muscle stem cell regenerative capacity in injured muscle.

We here demonstrate that (E)-1-(3-aminophenyl)-3-(5-bromo-4-hydroxy-2-methoxyphenyl)prop-2-en-1-one (SN159) is a novel peroxisome proliferator-activated receptor (PPAR) partial agonist that improves insulin sensitivity. SN159 interacted directly with PPARα and PPARγ, which were confirmed by LanthaScreen ligand binding assay and molecular docking study. SN159 treatment leads to a significant improvement of insulin sensitivity, resulting in enhancing glucose uptake in muscle cells. SN159 stimulated adipogenic differentiation of 3T3-L1 preadipocytes, however, the effects were much weaker than those of PPARγ agonist troglitazone. In parallel, SN159 increased weakly the transcriptional activities of PPARα/γ, compared to the positive control. Furthermore, PPARγ activation and adipogenic differentiation by troglitazone were significantly reduced by treatment with SN159, indicating that SN159 is a partial agonist of PPARs. SN159 was able to enhance fatty acid oxidation and glucose utilization through the dual activation of PPARα/γ. Taken together, these results suggest that SN159 is a novel PPAR partial agonist, which can be used as potential therapeutic agents against type 2 diabetes and related metabolic disorders by enhancing glucose and lipid metabolism.

Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) regulates postnatal myogenesis by alleviating myostatin activity, but the molecular mechanisms by which it regulates myogenesis are not fully understood. In this study, we investigate molecular mechanisms of PPARβ/δ in myoblast differentiation. C2C12 myoblasts treated with a PPARβ/δ agonist, GW0742 exhibit enhanced myotube formation and muscle-specific gene expression. GW0742 treatment dramatically activates promyogenic kinases, p38MAPK and Akt, in a dose-dependent manner. GW0742-stimulated myoblast differentiation is mediated by p38MAPK and Akt, since it failed to restore myoblast differentiation repressed by inhibition of p38MAPK and Akt. In addition, GW0742 treatment enhances MyoD-reporter activities. Consistently, overexpression of PPARβ/δ enhances myoblast differentiation accompanied by elevated activation of p38MAPK and Akt. Collectively, these results suggest that PPARβ/δ enhances myoblast differentiation through activation of promyogenic signaling pathways.

The present study demonstrated that protein arginine methyltransferase 6 (PRMT6) negatively regulates the activity of peroxisome proliferator‑activated receptor γ (PPARγ). The results indicated that the overexpression of PRMT6 inhibited the transactivity of PPARγ and subsequently decreased the expression levels of PPARγ target genes. Contrarily, the depletion or inhibition of PRMT6 increased PPARγ reporter activity and the expression of its target genes. It was also confirmed that PRMT6 was involved in the process of adipocyte differentiation. In addition, PRMT6 interacted with, but did not methylate, PPARγ. PRMT6 bound to the PPAR‑responsive regulatory element of the adipocyte Protein 2 (aP2) promoter in conjunction with PPARγ and generated the repressive epigenetic mark arginine 2 on histone H3 asymmetric di‑methylation, which suppressed aP2 gene expression. Therefore, PRMT6 may serve as an important regulator of PPARγ activity in adipogenic differentiation and may be an attractive therapeutic target for human metabolic diseases.

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is the main lipophilic flavonoid obtained from the Artemisia species. Eupatilin has been reported to have anti-apoptotic, anti-oxidative and anti-inflammatory activities. Previously, we found that eupatilin increases transcriptional activity and expression of peroxisome proliferator-activated receptor α (PPARα) in a keratinocyte cell line and acts as an agonist of PPARα. PPARα agonists ameliorate atopic dermatitis (AD) and restore the skin barrier function. In this study, we confirmed that the effects of eupatilin improved AD-like symptoms in an oxazolone-induced AD-like mouse model. Furthermore, we found that eupatilin suppressed the levels of serum immunoglobulin E (IgE), interleukin-4 (IL-4), and AD involved cytokines, such as tumor necrosis factor α (TNFα), interferon-γ (IFN-γ), IL-1β, and thymic stromal lymphopoietin (TSLP), IL-33, IL-25 and increased the levels of filaggrin and loricrin in the oxazolone-induced AD-like mouse model. Taken together, our data suggest that eupatilin is a potential candidate for the treatment of AD.

In the present study, the anti-diabetic effects of amorphastilbol (APH) from Amorpha fruticosa (AF) were evaluated in high-fat-diet (HFD) mice. HFD-induced blood glucose and insulin levels are significantly reduced in AF extract or APH treatment groups. HFD-induced weight gain was reduced by AF treatment, which is accompanied by reduction of fat mass and adipocyte size and number in white adipose tissues. Furthermore, total cholesterol and low-density lipoprotein-cholesterol levels are decreased in AF- or APH-treated mice. In addition, AF and APH are able to improve insulin sensitivity through inhibition of protein tyrosine phosphatase 1B, a negative regulator of the insulin-signaling pathway. Taken together, the data suggest that AF has beneficial effects on glucose and lipid metabolism and its pharmacological effects are driven, in part, by its active component, APH. Therefore, AF and APH can be used as potential therapeutic agents against type 2 diabetes and associated metabolic disorders, including obesity, by enhancing glucose and lipid metabolism.

The activation of MyoD family transcription factors is critical for myogenic differentiation, which is fundamental to the regeneration of skeletal muscle after injury. Kazinol-P (KP) from Broussonetia kazinoki (B. kazinoki), a natural compound, has been reported to possess an anti-oxidant function. In a screen of natural compounds for agonists of the MyoD activity, we identified KP and examined its effect on myoblast differentiation. Consistently, KP enhanced the myotube formation, accompanied with upregulation of myogenic markers such as MHC, Myogenin and Troponin-T. KP treatment in C2C12 myoblasts led to strong activation of a key promyogenic kinase p38MAPK in a dose, and time-dependent manner. Furthermore, KP treatment enhanced the MyoD-mediated trans-differentiation of 10T1/2 fibroblasts into myoblasts. Taken together, KP promotes myogenic differentiation through activation of p38MAPK and MyoD transcription activities. Thus KP may be a potential therapeutic candidate to prevent fibrosis and improve muscle regeneration and repair.

Pectolinarin and pectolinarigenin have been reported to be major compounds in Cirsium setidens. In the present study, we demonstrated inhibitory effects of pectolinarin and pectolinarigenin from C. setidens on melanogenesis. Melanin synthesis was decreased in both pectolinarin- and pectolinarigenin-treated melan-a cells and in a reconstructed human skin model. However, pectolinarigenin treatment showed more potent inhibitory activity of melanin synthesis than did pectolinarin treatment. The concentrations of pectolinarin and pectolinarigenin in C. setidens water extracts were determined by HPLC. Unfortunately, the amount of pectolinarigenin of C. setidens water extract was lower than that of pectolinarin. To increase the pectolinarigenin content in C. setidens water extract, several component conversion methods were studied. Consequently, we identified that microwave irradiation under 1% acetic acid was an optimum sugar elimination method.

Background Black ginseng (BG) has greatly enhanced pharmacological activities relative to white or red ginseng. However, the effect and molecular mechanism of BG on muscle growth has not yet been examined. In this study, we investigated whether BG could regulate myoblast differentiation and myotube hypertrophy. Methods BG-treated C2C12 myoblasts were differentiated, followed by immunoblotting for myogenic regulators, immunostaining for a muscle marker, myosin heavy chain or immunoprecipitation analysis for myogenic transcription factors. Results BG treatment of C2C12 cells resulted in the activation of Akt, thereby enhancing heterodimerization of MyoD and E proteins, which in turn promoted muscle-specific gene expression and myoblast differentiation. BG-treated myoblasts formed larger multinucleated myotubes with increased diameter and thickness, accompanied by enhanced Akt/mTOR/p70S6K activation. Furthermore, the BG treatment of human rhabdomyosarcoma cells restored myogenic differentiation. Conclusion BG enhances myoblast differentiation and myotube hypertrophy by activating Akt/mTOR/p70S6k axis. Thus, our study demonstrates that BG has promising potential to treat or prevent muscle loss related to aging or other pathological conditions, such as diabetes.

Prevention of age-associated reduction in muscle mass and function is required to manage a healthy life. Supplemental (-)-Epicatechin (EC) appears to act as a potential regulator for muscle growth and strength. However, its cellular and molecular mechanisms as a potential muscle growth agent have not been studied well. In the current study, we investigated a role of EC in differentiation of muscle progenitors to gain the molecular insight into how EC regulates muscle growth. EC enhanced myogenic differentiation in a dose-dependent manner through stimulation of promyogenic signaling pathways, p38MAPK and Akt. EC treatment elevated MyoD activity by enhancing its heterodimerization with E protein. Consistently, EC also positively regulated myogenic conversion and differentiation of fibroblasts. In conclusion, EC has a potential as a therapeutic or nutraceutical remedy to treat degenerative muscle diseases or age-related muscle weakness.

The purpose of this study was to identify conditions that will increase the sensitivity of resistant cancer cells to anti-mitotic drugs. Currently, atovaquine (ATO), chloroquine (CHL), primaquine (PRI), mefloquine (MEF), artesunate (ART), and doxycycline (DOY) are the most commonly used anti-malarial drugs. Herein, we tested whether anti-malarial drugs can sensitize drug-resistant KBV20C cancer cells. None of the six tested anti-malarial drugs was found to better sensitize the drug-resistant cells compared to the sensitive KB cells. With an exception of DOY, all other anti-malarial drugs tested could sensitize both KB and KBV20C cells to a similar extent, suggesting that anti-malarial drugs could be used for sensitive as well as resistant cancer cells. Furthermore, we examined the effects of anti-malarial drugs in combination with an antimitotic drug, vinblastine (VIN) on the sensitisation of resistant KBV20C cells. Using viability assay, microscopic observation, assessment of cleaved PARP, and Hoechst staining, we identified that two anti-malarial drugs, PRI and MEF, highly sensitized KBV20C-resistant cells to VIN treatment. Moreover, PRI- or MEF-induced sensitisation was not observed in VIN-treated sensitive KB parent cells, suggesting that the observed effect is specific to resistant cancer cells. We demonstrated that the PRI and MEF sensitisation mechanism mainly depends on the inhibition of p-glycoprotein (P-gp). Our findings may contribute to the development of anti-malarial drug-based combination therapies for patients resistant to anti-mitotic drugs.