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Antiviral Research Oct 2018While combination antiretroviral therapy (cART) has successfully converted HIV to a chronic but manageable infection in many parts of the world, HIV continues to persist... (Review)
Review
While combination antiretroviral therapy (cART) has successfully converted HIV to a chronic but manageable infection in many parts of the world, HIV continues to persist within latent cellular reservoirs, which can become reactivated at any time to produce infectious virus. New therapies are therefore needed not only for HIV suppression but also for containing or eliminating HIV reservoirs. Compounds derived from plant, marine, and other natural products have been found to combat HIV infection and/or target HIV reservoirs, and these discoveries have substantially guided current HIV therapy-based studies. Here we summarize the role of natural product-derived compounds in current HIV suppression, remission, and cure strategies.
Topics: Anti-HIV Agents; Biological Products; Bryostatins; Depsipeptides; Disease Reservoirs; Diterpenes; Drug Discovery; Gene Products, tat; HIV Infections; HIV-1; Histone Deacetylase Inhibitors; Humans; Phorbol Esters; Virus Latency; Vorinostat; rev Gene Products, Human Immunodeficiency Virus
PubMed: 30063970
DOI: 10.1016/j.antiviral.2018.07.016 -
Biochimica Et Biophysica Acta.... Dec 2017In LNCaP cells that stably express α-adrenergic receptors, oxymetazoline increased intracellular calcium and receptor phosphorylation, however, this agonist was a weak...
In LNCaP cells that stably express α-adrenergic receptors, oxymetazoline increased intracellular calcium and receptor phosphorylation, however, this agonist was a weak partial agonist, as compared to noradrenaline, for calcium signaling. Interestingly, oxymetazoline-induced receptor internalization and desensitization displayed greater effects than those induced by noradrenaline. Phorbol myristate acetate induced modest receptor internalization and minimal desensitization. α-Adrenergic receptor interaction with β-arrestins (colocalization/coimmunoprecipitation) was induced by noradrenaline and oxymetazoline and, to a lesser extent, by phorbol myristate acetate. Oxymetazoline was more potent and effective than noradrenaline in inducing ERK 1/2 phosphorylation. Mass spectrometric analysis of immunopurified α-adrenergic receptors from cells treated with adrenergic agonists and the phorbol ester clearly showed that phosphorylated residues were present both at the third intracellular loop and at the carboxyl tail. Distinct phosphorylation patterns were observed under the different conditions. The phosphorylated residues were: a) Baseline and all treatments: T233; b) noradrenaline: S220, S227, S229, S246, S250, S389; c) oxymetazoline: S227, S246, S381, T384, S389; and d) phorbol myristate acetate: S246, S250, S258, S351, S352, S401, S402, S407, T411, S413, T451. Our novel data, describing the α-AR phosphorylation sites, suggest that the observed different phosphorylation patterns may participate in defining adrenoceptor localization and action, under the different conditions examined.
Topics: Calcium Signaling; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Mass Spectrometry; Norepinephrine; Oxymetazoline; Phosphorylation; Protein Kinase C; Proteolysis; Receptors, Adrenergic, alpha-1; Tetradecanoylphorbol Acetate
PubMed: 28888989
DOI: 10.1016/j.bbamcr.2017.09.002 -
The Biochemical Journal Aug 2022The protein kinases PAK4, PAK5 and PAK6 comprise a family of ohnologues. In multiple cancers including melanomas PAK5 most frequently carries non-synonymous mutations;...
The protein kinases PAK4, PAK5 and PAK6 comprise a family of ohnologues. In multiple cancers including melanomas PAK5 most frequently carries non-synonymous mutations; PAK6 and PAK4 have fewer; and PAK4 is often amplified. To help interpret these genomic data, initially we compared the cellular regulation of the sister kinases and their roles in melanoma cells. In common with many ohnologue protein kinases, PAK4, PAK5 and PAK6 each have two 14-3-3-binding phosphosites of which phosphoSer99 is conserved. PAK4 localises to the leading edge of cells in response to phorbol ester-stimulated binding of 14-3-3 to phosphoSer99 and phosphoSer181, which are phosphorylated by two different PKCs or PKDs. These phosphorylations of PAK4 are essential for its phorbol ester-stimulated phosphorylation of downstream substrates. In contrast, 14-3-3 interacts with PAK5 in response to phorbol ester-stimulated phosphorylation of Ser99 and epidermal growth factor-stimulated phosphorylation of Ser288; whereas PAK6 docks onto 14-3-3 and is prevented from localising to cell-cell junctions when Ser133 is phosphorylated in response to cAMP-elevating agents via PKA and insulin-like growth factor 1 via PKB/Akt. Silencing of PAK4 impairs viability, migration and invasive behaviour of melanoma cells carrying BRAFV600E or NRASQ61K mutations. These defects are rescued by ectopic expression of PAK4, more so by a 14-3-3-binding deficient PAK4, and barely by PAK5 or PAK6. Together these genomic, biochemical and cellular data suggest that the oncogenic properties of PAK4 are regulated by PKC-PKD signalling in melanoma, while PAK5 and PAK6 are dispensable in this cancer.
Topics: Humans; Melanoma; Phorbol Esters; Phosphorylation; Protein Kinases; p21-Activated Kinases
PubMed: 35969127
DOI: 10.1042/BCJ20220184 -
Biochimica Et Biophysica Acta. General... Nov 2017Resveratrol (1) is a naturally occurring polyphenol that has been implicated in neuroprotection. One of resveratrol's several biological targets is Ca-sensitive protein...
BACKGROUND
Resveratrol (1) is a naturally occurring polyphenol that has been implicated in neuroprotection. One of resveratrol's several biological targets is Ca-sensitive protein kinase C alpha (PKCα). Resveratrol inhibits PKCα by binding to its activator-binding C1 domain. Munc13-1 is a C1 domain-containing Ca-sensitive SNARE complex protein essential for vesicle priming and neurotransmitter release.
METHODS
To test if resveratrol could also bind and inhibit Munc13-1, we studied the interaction of resveratrol and its derivatives, (E)-1,3-dimethoxy-5-(4-methoxystyryl)benzene, (E)-5,5'-(ethene-1,2-diyl)bis(benzene-1,2,3-triol), (E)-1,2-bis(3,4,5-trimethoxyphenyl)ethane, and (E)-5-(4-(hexadecyloxy)-3,5-dihydroxystyryl)benzene-1,2,3-triol with Munc13-1 by studying its membrane translocation from cytosol to plasma membrane in HT22 cells and primary hippocampal neurons.
RESULTS
Resveratrol, but not the derivatives inhibited phorbol ester-induced Munc13-1 translocation from cytosol to membrane in HT22 cells and primary hippocampal neurons, as evidenced by immunoblot analysis and confocal microscopy. Resveratrol did not show any effect on Munc13-1, a mutant which is not sensitive to phorbol ester. Binding studies with Munc13-1 C1 indicated that resveratrol competes with phorbol ester for the binding site. Molecular docking and dynamics studies suggested that hydroxyl groups of resveratrol interact with phorbol-ester binding residues in the binding pocket.
CONCLUSIONS AND SIGNIFICANCE
This study characterizes Munc13-1 as a target of resveratrol and highlights the importance of dietary polyphenol in the management of neurodegenerative diseases.
Topics: Animals; Binding Sites; Free Radical Scavengers; Hippocampus; Humans; Mice; Molecular Docking Simulation; Nerve Tissue Proteins; Neurons; Phorbol Esters; Primary Cell Culture; Protein Kinase C-alpha; Resveratrol; SNARE Proteins; Stilbenes; Synaptic Transmission
PubMed: 28713022
DOI: 10.1016/j.bbagen.2017.07.006 -
Chinese Journal of Natural Medicines Feb 2024In this study, 37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated, building upon our previous synthesis of 51 phorbol...
In this study, 37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated, building upon our previous synthesis of 51 phorbol derivatives. 12-Para-electron-acceptor-trans-cinnamoyl-13-decanoyl phorbol derivatives stood out, demonstrating remarkable anti-HIV-1 activities and inhibitory effects on syncytia formation. These derivatives exhibited a higher safety index compared with the positive control drug. Among them, 12-(trans-4-fluorocinnamoyl)-13-decanoyl phorbol, designated as compound 3c, exhibited the most potent anti-HIV-1 activity (EC 2.9 nmol·L, CC/EC 11 117.24) and significantly inhibited the formation of syncytium (EC 7.0 nmol·L, CC/EC 4891.43). Moreover, compound 3c is hypothesized to act both as an HIV-1 entry inhibitor and as an HIV-1 reverse transcriptase inhibitor. Isothermal titration calorimetry and molecular docking studies indicated that compound 3c may also function as a natural activator of protein kinase C (PKC). Therefore, compound 3c emerges as a potential candidate for developing new anti-HIV drugs.
Topics: Molecular Docking Simulation; Anti-HIV Agents; Phorbols; Phorbol Esters; HIV Reverse Transcriptase; Structure-Activity Relationship
PubMed: 38342567
DOI: 10.1016/S1875-5364(24)60587-X -
Biomolecules & Therapeutics Mar 2018The present study was undertaken to investigate the influence of hypothermia on endothelium-independent vascular smooth muscle contractility and to determine the...
The present study was undertaken to investigate the influence of hypothermia on endothelium-independent vascular smooth muscle contractility and to determine the mechanism underlying the relaxation. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Hypothermia significantly inhibited fluoride-, thromboxane A-, phenylephrine-, and phorbol ester-induced vascular contractions regardless of endothelial nitric oxide synthesis, suggesting that another pathway had a direct effect on vascular smooth muscle. Hypothermia significantly inhibited the fluoride-induced increase in pMYPT1 level and phorbol ester-induced increase in pERK1/2 level, suggesting inhibition of Rho-kinase and MEK activity and subsequent phosphorylation of MYPT1 and ERK1/2. These results suggest that the relaxing effect of moderate hypothermia on agonist-induced vascular contraction regardless of endothelial function involves inhibition of Rho-kinase and MEK activities.
PubMed: 28208012
DOI: 10.4062/biomolther.2016.233 -
International Journal of Molecular... Nov 2022Neutrophil extracellular traps (NETs) are found in patients with various diseases, including cardiovascular diseases. We previously reported that copper-oxidized...
Neutrophil extracellular traps (NETs) are found in patients with various diseases, including cardiovascular diseases. We previously reported that copper-oxidized low-density lipoprotein (oxLDL) promotes NET formation of neutrophils, and that the resulting NETs increase the inflammatory responses of endothelial cells. In this study, we investigated the effects of high-density lipoproteins (HDL) on NET formation. HL-60-derived neutrophils were treated with phorbol 12-myristate 13-acetate (PMA) and further incubated with oxLDL and various concentrations of HDL for 2 h. NET formation was evaluated by quantifying extracellular DNA and myeloperoxidase. We found that the addition of native HDL partially decreased NET formation of neutrophils induced by oxLDL. This effect of HDL was lost when HDL was oxidized. We showed that oxidized phosphatidylcholines and lysophosphatidylcholine, which are generated in oxLDL, promoted NET formation of PMA-primed neutrophils, and NET formation by these products was completely blocked by native HDL. Furthermore, we found that an electronegative subfraction of LDL, LDL(-), which is separated from human plasma and is thought to be an in vivo oxLDL, was capable of promoting NET formation. These results suggest that plasma lipoproteins and their oxidative modifications play multiple roles in promoting NET formation, and that HDL acts as a suppressor of this response.
Topics: Humans; Lipoproteins, HDL; Extracellular Traps; Phospholipids; Endothelial Cells; Lipoproteins, LDL; Tetradecanoylphorbol Acetate
PubMed: 36430470
DOI: 10.3390/ijms232213992 -
Phorbol myristate acetate induces differentiation of THP-1 cells in a nitric oxide-dependent manner.Nitric Oxide : Biology and Chemistry May 2021THP-1 cells, a human leukemia monocytic cell line, differentiated by phorbol myristate acetate (PMA) are widely used as surrogate of human macrophages. Differentiated...
INTRODUCTION
THP-1 cells, a human leukemia monocytic cell line, differentiated by phorbol myristate acetate (PMA) are widely used as surrogate of human macrophages. Differentiated THP-1 cells acquire macrophage-like characteristics including more adherence and altered cell function. Nitric oxide (NO), an intracellular messenger, is critical in regulating cell differentiation. Here we elucidated whether NO relates to PMA-induced monocyte-to-macrophage differentiation of THP-1 cells. The mutual regulation of calcium and NO was also investigated.
MATERIAL & METHODS
THP-1 cells were incubated with PMA for 24 h, followed by assay of adherence, morphological change, migration or IL-1β release. L-N-Nitroarginine methyl ester (l-NAME, a nitric oxide synthase inhibitor) or BAPTA-AM (a calcium chelator) was added before PMA stimulation, and levels of calcium and NO were measured. Furthermore, a selective inhibitor of inducible nitric oxide synthase (iNOS) activity was employed to study the role of iNOS.
RESULTS AND DISCUSSION
Effects of PMA on upregulation of adherence, lipopolysaccharide-triggered IL-1β, and migration ability of THP-1 cells were consistent with NO concentrations. Both l-NAME and BAPTA-AM mitigated effects of PMA on THP-1 cells differentiation. BAPTA-AM decreased levels of NO, while l-NAME had no effect on calcium levels. Of note, inhibition of iNOS activity decreased PMA-triggered upregulation of NO.
CONCLUSION
PMA induced differentiation of THP-1 cells partially in a NO-dependent manner. The calcium signaling may mediate PMA-triggered upregulation of NO.
Topics: Calcium; Calcium Signaling; Cell Differentiation; Cell Movement; Humans; Macrophages; Monocytes; Nitric Oxide; Nitric Oxide Synthase Type II; THP-1 Cells; Tetradecanoylphorbol Acetate; Up-Regulation
PubMed: 33667621
DOI: 10.1016/j.niox.2021.02.002 -
European Journal of Pharmacology Oct 2020In a cell line, stably expressing α-adrenoceptors fused to the mCherry red fluorescent protein, noradrenaline, methoxamine, and oxymetazoline induced...
In a cell line, stably expressing α-adrenoceptors fused to the mCherry red fluorescent protein, noradrenaline, methoxamine, and oxymetazoline induced concentration-dependent increases in intracellular calcium. All of these agents increase α-adrenoceptor phosphorylation and internalization. Transient co-expression of these receptors with Rab proteins tagged with the enhanced Green Fluorescent Protein was employed to estimate α-adrenoceptor-Rab interaction using Förster Resonance Energy Transfer. Noradrenaline and methoxamine increased α-adrenoceptor interaction with Rab5 and Rab7 but did not modify it with Rab9. Oxymetazoline induced adrenoceptor interaction with Rab5 and Rab9 and only an insignificant increase in Rab7 signal. Phorbol myristate acetate increased α-adrenoceptor interaction with Rab5 and Rab9 but did not modify it with Rab7. The agonists and the active phorbol ester, all of which induce receptor phosphorylation and internalization, favor receptor interaction with Rab5, i.e., association with early endosomes. Cell stimulation with phorbol myristate acetate induced the α-adrenoceptors to interact with the late endosomal marker, Rab9, suggesting that the receptors are directed to slow recycling endosomes once they have transited to the Trans-Golgi network to be retrieved to the plasma membrane. The agonists noradrenaline and methoxamine likely induce a faster recycling and might direct some of the adrenoceptors toward degradation and/or very slow recycling to the plasma membrane. Oxymetazoline produced a mixed pattern of interaction with the Rab proteins. These data indicate that α-adrenoceptor agonists can trigger different vesicular traffic and receptor fates within the cells.
Topics: Adrenergic alpha-1 Receptor Agonists; Calcium; Cell Line; Endosomes; Humans; Luminescent Proteins; Methoxamine; Norepinephrine; Oxymetazoline; Phorbol Esters; Phosphorylation; Receptors, Adrenergic, alpha-1; Tetradecanoylphorbol Acetate; rab GTP-Binding Proteins; rab5 GTP-Binding Proteins; trans-Golgi Network; Red Fluorescent Protein
PubMed: 32750368
DOI: 10.1016/j.ejphar.2020.173423 -
Molecules (Basel, Switzerland) Oct 2022is a xerophytic species widely used in Mexico as an ingredient in sweet food and fermented beverages; it is also used in traditional medicine to treat wound pain and...
is a xerophytic species widely used in Mexico as an ingredient in sweet food and fermented beverages; it is also used in traditional medicine to treat wound pain and rheumatic damage, and as a remedy for psoriasis. Among the various extracts and extract fractions that have been evaluated for their anti-inflammatory effects, the acetonic extract (AaAc) and its acetonic (F-Ac) and methanolic (F-MeOH) fractions were the most active in a xylene-induced ear edema model in mice, when orally administered. Four fractions resulting from chemically resolving F-Ac (F1-F4) were locally applied to mice with phorbol 12-myristate 13-acetate (TPA)-induced ear inflammation; F1 inhibited inflammation by 70% and was further evaluated in a carrageenan-induced mono-arthritis model. When administered at doses of 12.5, 25, and 50 mg/kg, F1 reduced articular edema and the spleen index. In addition, it modulated spleen and joint cytokine levels and decreased pain. According to a GC-MS analysis, the main components of F1 are fatty-acid derivatives: palmitic acid methyl ester, palmitic acid ethyl ester, octadecenoic acid methyl ester, linoleic acid ethyl ester, and oleic acid ethyl ester.
Topics: Mice; Animals; Agave; Anti-Inflammatory Agents; Plant Extracts; Fatty Acids; Edema; Carrageenan; Pain; Esters; Phytotherapy
PubMed: 36364031
DOI: 10.3390/molecules27217204