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Plants (Basel, Switzerland) Feb 2023Mycotoxins are one of the most important sources for the discovery of new pesticides and drugs because of their chemical structural diversity and fascinating bioactivity...
Mycotoxins are one of the most important sources for the discovery of new pesticides and drugs because of their chemical structural diversity and fascinating bioactivity as well as unique novel targets. Here, the effects of four mycotoxins, fumagillin, mevastatin, radicicol, and wortmannin, on photosynthesis were investigated to identify their precise sites of action on the photosynthetic apparatus of . Our results showed that these four mycotoxins have multiple targets, acting mainly on photosystem II (PSII). Their mode of action is similar to that of diuron, inhibiting electron flow beyond the primary quinone electron acceptor (Q) by binding to the secondary quinone electron acceptor (Q) site of the D1 protein, thereby affecting photosynthesis. The results of PSII oxygen evolution rate and chlorophyll (Chl) fluorescence imaging suggested that fumagillin strongly inhibited overall PSII activity; the other three toxins also exhibited a negative influence at the high concentration. Chl fluorescence kinetics and the JIP test showed that the inhibition of electron transport beyond Q was the most significant feature of the four mycotoxins. Fumagillin decreased the rate of O evolution by interrupting electron transfer on the PSII acceptor side, and had multiple negative effects on the primary photochemical reaction and PSII antenna size. Mevastatin caused a decrease in photosynthetic activity, mainly due to the inhibition of electron transport. Both radicicol and wortmannin decreased photosynthetic efficiency, mainly by inhibiting the electron transport efficiency of the PSII acceptor side and the activity of the PSII reaction centers. In addition, radicicol reduced the primary photochemical reaction efficiency and antenna size. The simulated molecular model of the four mycotoxins' binding to D1 protein indicated that the residue D1-Phe265 is their common site at the Q site. This is a novel target site different from those of commercial PSII herbicides. Thus, the interesting effects of the four mycotoxins on PSII suggested that they provide new ideas for the design of novel and efficient herbicide molecules.
PubMed: 36771749
DOI: 10.3390/plants12030665 -
World Journal of Gastroenterology May 2016To investigate the influence of phosphatidylinositol-3-kinase protein kinase B (PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under...
AIM
To investigate the influence of phosphatidylinositol-3-kinase protein kinase B (PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia.
METHODS
Esophageal carcinoma cell lines Eca109 and TE13 were cultured under hypoxia environment, and the protein, mRNA and activity levels of hypoxia inducible factor-1 alpha (HIF-1α), glucose transporter 1, hexokinase-II, phosphofructokinase 2 and lactate dehydrogenase-A were determined. Supernatant lactic acid concentrations were also detected. The PI3K/AKT signaling pathway was then inhibited with wortmannin, and the effects of hypoxia on the expression or activities of HIF-1α, associated glycolytic enzymes and lactic acid concentrations were observed. Esophageal carcinoma cells were then transfected with interference plasmid with HIF-1α-targeting siRNA to assess impact of the high expression of HIF-1α on glycolysis.
RESULTS
HIF-1α is highly expressed in the esophageal carcinoma cell lines tested, and with decreasing levels of oxygen, the expression of HIF-1α and the associated glycolytic enzymes and the extracellular lactic acid concentration were enhanced in the esophageal carcinoma cell lines Eca109 and TE13. In both normoxia and hypoxic conditions, the level of glycolytic enzymes and the secretion of lactic acid were both reduced by wortmannin. The expression and activities of glycolytic enzymes and the lactic acid concentration in cells were reduced by inhibiting HIF-1α, especially the decreasing level of glycolysis was significant under hypoxic conditions.
CONCLUSION
The PI3K/AKT pathway and HIF-1α are both involved in the process of glycolysis in esophageal cancer cells.
Topics: Androstadienes; Carcinoma; Cell Line, Tumor; Esophageal Neoplasms; Gene Expression Regulation, Neoplastic; Glycolysis; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lactic Acid; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; RNA Interference; RNA, Messenger; Signal Transduction; Time Factors; Transfection; Tumor Hypoxia; Tumor Microenvironment; Wortmannin
PubMed: 27239113
DOI: 10.3748/wjg.v22.i20.4868 -
Nature Jan 2022The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) has a central role in non-homologous end joining, one of the two main pathways that detect and repair DNA...
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) has a central role in non-homologous end joining, one of the two main pathways that detect and repair DNA double-strand breaks (DSBs) in humans. DNA-PKcs is of great importance in repairing pathological DSBs, making DNA-PKcs inhibitors attractive therapeutic agents for cancer in combination with DSB-inducing radiotherapy and chemotherapy. Many of the selective inhibitors of DNA-PKcs that have been developed exhibit potential as treatment for various cancers. Here we report cryo-electron microscopy (cryo-EM) structures of human DNA-PKcs natively purified from HeLa cell nuclear extracts, in complex with adenosine-5'-(γ-thio)-triphosphate (ATPγS) and four inhibitors (wortmannin, NU7441, AZD7648 and M3814), including drug candidates undergoing clinical trials. The structures reveal molecular details of ATP binding at the active site before catalysis and provide insights into the modes of action and specificities of the competitive inhibitors. Of note, binding of the ligands causes movement of the PIKK regulatory domain (PRD), revealing a connection between the p-loop and PRD conformations. Electrophoretic mobility shift assay and cryo-EM studies on the DNA-dependent protein kinase holoenzyme further show that ligand binding does not have a negative allosteric or inhibitory effect on assembly of the holoenzyme complex and that inhibitors function through direct competition with ATP. Overall, the structures described in this study should greatly assist future efforts in rational drug design targeting DNA-PKcs, demonstrating the potential of cryo-EM in structure-guided drug development for large and challenging targets.
Topics: Adenosine Triphosphate; Catalytic Domain; Cryoelectron Microscopy; DNA; DNA End-Joining Repair; DNA Repair; DNA-Activated Protein Kinase; HeLa Cells; Holoenzymes; Humans; Ku Autoantigen; Pyridazines; Quinazolines
PubMed: 34987222
DOI: 10.1038/s41586-021-04274-9 -
Nutrients Dec 2022Hair loss remains a significant problem that is difficult to treat; therefore, there is a need to identify safe natural materials that can help patients with hair loss....
Hair loss remains a significant problem that is difficult to treat; therefore, there is a need to identify safe natural materials that can help patients with hair loss. We evaluated the hair anagen activation effects of limonin, which is abundant in immature citrus fruits. Limonin increased the proliferation of rat dermal papilla cells (rDPC) by changing the levels of cyclin D1 and p27, and increasing the number of BrdU-positive cells. Limonin increased autophagy by decreasing phosphorylated mammalian target of rapamycin levels and increasing the phospho-Raptor, ATG7 and LC3B. Limonin also activated the Wnt/β-catenin pathway by increasing phospho-β-catenin levels. XAV939, a Wnt/β-catenin inhibitor, inhibited these limonin-induced changes, including induced autophagy, BrdU-positive cells, and cell proliferation. Limonin increased the phosphorylated AKT levels in both two-dimensional cultured rDPC and three-dimensional spheroids. Treatment with the PI3K inhibitor wortmannin inhibited limonin-induced proliferation, and disrupted other limonin-mediated changes, including decreased p27, increased BrdU-positive cells, induced autophagy, and increased ATG7 and LC3B levels. Wortmannin also inhibited limonin-induced cyclin D1 and LC3 expression in spheroids. Collectively, these results indicate that limonin can enhance anagen signaling by activating autophagy via targeting the Wnt/β-catenin and/or PI3K/AKT pathways in rDPC, highlighting a candidate nutrient for hair loss treatment.
Topics: Animals; Rats; Alopecia; beta Catenin; Bromodeoxyuridine; Cell Proliferation; Cells, Cultured; Cyclin D1; Fruit; Hair Follicle; Limonins; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Wnt Signaling Pathway; Wortmannin
PubMed: 36558517
DOI: 10.3390/nu14245358 -
Nutrients Jun 2015Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum...
Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE), also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma "antihypertensive tea" is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO)-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs). Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase), wortmannin (30 nM) and LY294002 (20 µM; PI3 (phosphatidylinositol3)-Kinase inhibitor), N(G)-nitro-L-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS)) and ODQ (1 µM; soluble guanylyl cyclase inhibitor). Total nitrite and nitrate (NOx) level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NOx level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.
Topics: Animals; Aorta; Apocynum; Drugs, Chinese Herbal; Endothelium, Vascular; Humans; Male; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinases; Phosphorylation; Plant Leaves; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Umbilical Veins; Vasodilation; src-Family Kinases
PubMed: 26133970
DOI: 10.3390/nu7075220 -
International Journal of Cardiology.... Oct 2021Studies of insulin-like growth factor 1 (IGF-1) as a novel therapy for the treatment of cardiovascular diseases have proven promising. However, elevated IGF-1 levels...
BACKGROUND
Studies of insulin-like growth factor 1 (IGF-1) as a novel therapy for the treatment of cardiovascular diseases have proven promising. However, elevated IGF-1 levels have also been associated with poor patient outcomes in heart failure with reduced ejection fraction. IGF-1 therapy has additionally been shown to not be beneficial in the percutaneous coronary intervention setting. Although IGF-1 activation of the PI3K/Akt and ERK1/2 pathways have been demonstrated as cardioprotective, other cellular mechanisms have not been fully investigated.
METHODS
Neonatal rat cardiac myocytes (NCMs) and fibroblasts (NCFs) were isolated from 1 to 2-day old pups using enzymatic digestion. NCMs and NCFs were pre-treated with IGF binding protein 6, inhibitors for the PI3K/Akt Wortmannin, ERK1/2 U0126, Rho Associated Protein Kinase (ROCK) GSK576371, Apoptosis Signal-regulating Kinase-1 (ASK-1) G2261818A, and p38MAPK RWJ67657 pathways before stimulation with IGF-1 for 62 and 50 h, respectively. Cardiac myocyte hypertrophy and fibroblast collagen synthesis were determined by H-leucine and H-proline incorporation, respectively.
RESULTS
IGF-1 dose-dependently stimulated NCM hypertrophy and NCF collagen synthesis.Treatment with IGFBP6 and the kinase inhibitors, Wortmannin, U0126, GSK576371, G2261818A and RWJ67657 significantly inhibited IGF-1 stimulated NCM hypertrophy and NCF collagen synthesis.
CONCLUSION
This study is the first to demonstrate that IGF-1 treatment in NCMs and NCFs activates the ROCK, ASK-1 and p38MAPK pathways. Future research may be guided by consideration of the PI3K/Akt and ERK1/2 pathways potentially increasing collagen synthesis, and the utilisation of a biased agonist to reduce activation of the ROCK, ASK-1 and p38MAPK pathways to maximise cardioprotective benefit whilst mitigating risks.
PubMed: 34401470
DOI: 10.1016/j.ijcha.2021.100852 -
American Journal of Physiology.... Mar 2021Progesterone acts directly on vascular smooth muscle cells (VSMCs) through activation of membrane progesterone receptor α (mPRα)-dependent signaling to rapidly...
Progesterone acts directly on vascular smooth muscle cells (VSMCs) through activation of membrane progesterone receptor α (mPRα)-dependent signaling to rapidly decrease cytosolic Ca concentrations and induce muscle relaxation. However, it is not known whether this progesterone action involves uptake of Ca by the sarco/endoplasmic reticulum (SR) and increased sarco/endoplasmic reticulum Ca-ATPase (SERCA) activity. The present results show that treatment of cultured human VSMCs with progesterone and the selective mPR agonist Org OD-02-0 (OD 02-0) but not with the nuclear PR agonist R5020 increased SERCA protein expression, which was blocked by knockdown of mPRα with siRNA. Moreover, treatments with progesterone and OD 02-0, but not with R5020, increased phospholamban (PLB) phosphorylation, which would result in disinhibition of SERCA function. Progesterone and OD 02-0 significantly increased Ca levels in the SR and caused VSMC relaxation. These effects were blocked by pretreatment with cyclopiazonic acid (CPA), a SERCA inhibitor, and by knockdown of SERCA2 with siRNA, suggesting that SERCA2 plays a critical role in progesterone induction of VSMC relaxation. Treatment with inhibitors of inhibitory G proteins (Gi, NF023), MAP kinase (AZD 6244), Akt/Pi3k (wortmannin), and a Rho activator (calpeptin) blocked the progesterone- and OD 02-0-induced increase in Ca levels in the SR and SERCA expressions. These results suggest that the rapid effects of progesterone on cytosolic Ca levels and relaxation of VSMCs through mPRα involve regulation of the functions of SERCA2 and PLB through Gi, MAP kinase, and Akt signaling pathways and downregulation of RhoA activity. The rapid effects of progesterone on cytosolic Ca levels and relaxation of VSMCs through mPRα involve regulation of the functions of SERCA2 and PLB through Gi, MAP kinase, and Akt signaling pathways and downregulation of RhoA activity.
Topics: Cells, Cultured; Gene Expression Regulation, Enzymologic; Humans; Muscle Relaxation; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Progesterone; Receptors, Progesterone; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction; Umbilical Arteries
PubMed: 33427050
DOI: 10.1152/ajpendo.00359.2020 -
Clinical, Cosmetic and Investigational... 2022Autophagy is an important process for maintaining intracellular homeostasis and is deregulated in ultraviolet B (UVB)-induced skin injury. Salidroside (SAL) is an active...
INTRODUCTION
Autophagy is an important process for maintaining intracellular homeostasis and is deregulated in ultraviolet B (UVB)-induced skin injury. Salidroside (SAL) is an active ingredient extracted from , which is a herbal medicine that has shown protection against ultraviolet (UV) radiation. Here, we investigated the functions and mechanisms of SAL on UVB-induced skin cell oxidative damage and autophagy.
METHODS
Human immortalized keratinocyte cell line HaCaT was used as a cell model of UV injury. HaCaT cells were exposed to UVB irradiation and then incubated with SAL to investigate cell viability, lactate dehydrogenase (LSD) in culture media, intracellular reactive oxygen species (ROS) level, oxidative stress, autophagy, and regulatory effects on SIRT1 protein.
RESULTS
SAL pretreatment (25, 50 and 100 μM) increased cell viability and inhibited LDH release in UVB-challenged HaCaT cells. SAL (100 μM) significantly reduced intracellular ROS level and suppressed oxidative stress, with increased MDA content and increased SOD activity. In addition, SAL pretreatment enhanced autophagy in UVB-irradiated HaCaT cells, increased protein expressions of Beclin-1 and ATG7, and decreased protein expression of P62. We also found that pretreatment with SAL increased the SIRT1 protein in irradiated HaCaT cells. SAL protected UVB-induced damage in a dependent manner on autophagy and SIRT1, as SAL-induced increase in viability was significantly attenuated by specific autophagy inhibitor Wortmannin (1 μM) or SIRT1 inhibitor EX-527 (100 nM).
DISCUSSION
The present study results speculate that SAL suppresses UVB-induced injury and autophagy by enhancing SIRT1 expression.
PubMed: 35941856
DOI: 10.2147/CCID.S367233 -
American Journal of Physiology.... Mar 2020Excess androgen-induced obesity has become a public health problem, and its prevalence has increased substantially in recent years. Chemokine-like receptor 1 (CMKLR1), a...
Excess androgen-induced obesity has become a public health problem, and its prevalence has increased substantially in recent years. Chemokine-like receptor 1 (CMKLR1), a receptor of chemerin secreted by adipose tissue, is linked to adipocyte differentiation, adipose tissue development, and obesity. However, the effect of CMKLR1 signaling on androgen-mediated adiposity in vivo remains unclear. Using CMKLR1-knockout mice, we constructed an androgen-excess female mouse model through 5α-dihydrotestosterone (DHT) treatment and an androgen-deficient male mouse model by orchidectomy (ORX). For mechanism investigation, we used 2-(α-Naphthoyl) ethyltrimethylammonium iodide (α-NETA), an antagonist of CMKLR1, to suppress CMKLR1 in vivo and wortmannin, a PI3K signaling antagonist, to treat brown adipose tissue (BAT) explant cultures in vitro Furthermore, we used histological examination and quantitative PCR, as well as Western blot analysis, glucose tolerance tests, and biochemical analysis of serum, to describe the phenotypes and the changes in gene expression. We demonstrated that excess androgen in the female mice resulted in larger cells in the white adipose tissue (WAT) and the BAT, whereas androgen deprivation in the male mice induced a reduction in cell size. Both of these adipocyte size effects could be attenuated in the CMKLR1-knockout mice. CMKLR1 deficiency influenced the effect of androgen treatment on adipose tissue by regulating the mRNA expression of the androgen receptor (AR) and adipocyte markers (such as Fabp4 and Cidea). Moreover, suppression of CMKLR1 by α-NETA could also reduce the extent of the adipocyte cell enlargement caused by DHT. Furthermore, we found that DHT could reduce the levels of phosphorylated ERK (pERK) in the BAT, while CMKLR1 inactivation inhibited this effect, which had been induced by DHT, through the PI3K signaling pathway. These findings reveal an antiobesity role of CMKLR1 deficiency in regulating lipid accumulation, highlighting the scientific importance for the further development of small-molecule CMKLR1 antagonists as fundamental research tools and/or as potential drugs for use in the treatment of adiposity.
Topics: Adipocytes; Adipose Tissue, Brown; Androgens; Animals; Body Weight; Cell Size; Dihydrotestosterone; Female; Lipid Metabolism; MAP Kinase Signaling System; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Naphthalenes; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Quaternary Ammonium Compounds; Receptors, Chemokine; Wortmannin
PubMed: 31910029
DOI: 10.1152/ajpendo.00176.2019 -
Experimental and Therapeutic Medicine Feb 2018Polycystic ovary syndrome (PCOS) is a common gynecological endocrine disorder, which results in health problems such as menstrual disorders, hyperandrogenism and...
Polycystic ovary syndrome (PCOS) is a common gynecological endocrine disorder, which results in health problems such as menstrual disorders, hyperandrogenism and persistent anovulation. Hyperandrogenism and insulin resistance are the basic characteristics of PCOS. To investigate the combined effect of metformin and pioglitazone on POCS and the potential mechanisms, a rat model of PCOS was established by intramuscular injection of estradiol valerate (EV). The effect of metformin and pioglitazone monotherapy or combination therapy in control rats and PCOS rats was evaluated, involving the testosterone level, follicular development and insulin resistance. The potential mechanism for the therapeutic effect of metformin and pioglitazone on POCS was explored through using three inhibitors of the 5'adenosine monophosphate-activated protein kinase (AMPK)/phosphoinositide-3 kinase (PI3K)/c-Jun N-terminal kinase (JNK) pathway (Compound C, Wortmannin and SP600125). The results showed that EV-induced PCOS rats demonstrated hyperandrogenemia, hyperinsulinemia and follicular dysplasia. Metformin or pioglitazone monotherapy significantly suppressed the high level of testosterone, reduced the raised percentage of cystic follicles and primary follicles, promoted the number of early antral follicles, and markedly decreased the high concentration of fasting insulin and homeostatic model assessment for insulin resistance index in PCOS rats. In addition, metformin and pioglitazone combination therapy demonstrated greater efficacy than its individual components. Furthermore, individual or joint treatment with metformin and pioglitazone affected the phosphorylation level of JNK in PCOS rats. Compound C and Wortmannin eliminated the effect of metformin and pioglitazone combination therapy on improving the follicular growth in PCOS rats, whereas SP600125 treatment enhanced this combination therapy effect. These data suggested that metformin and pioglitazone combination therapy demonstrated great efficacy in ameliorating PCOS through regulating the AMPK/PI3K/JNK pathway.
PubMed: 29434814
DOI: 10.3892/etm.2017.5650