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Theranostics 2020Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem...
Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem cells (MSCs) ameliorate lupus symptoms by inhibiting T cells, whether they inhibit B cells has been controversial. Here we address this issue and reveal how to prime MSCs to inhibit B cells and improve the efficacy of MSCs in SLE. We examined the effect of MSCs on purified B cells and the therapeutic efficacy of MSCs in lupus-prone MRL. mice. We screened chemicals for their ability to activate MSCs to inhibit B cells. Mouse bone marrow-derived MSCs inhibited mouse B cells in a CXCL12-dependent manner, whereas human bone marrow-derived MSCs (hMSCs) did not inhibit human B (hB) cells. We used a chemical approach to overcome this hurdle and found that phorbol myristate acetate (PMA), phorbol 12,13-dibutyrate, and ingenol-3-angelate rendered hMSCs capable of inhibiting IgM production by hB cells. As to the mechanism, PMA-primed hMSCs attracted hB cells in a CXCL10-dependent manner and induced hB cell apoptosis in a PD-L1-dependent manner. Finally, we showed that PMA-primed hMSCs were better than naïve hMSCs at ameliorating SLE progression in MRL. mice. Taken together, our data demonstrate that phorbol esters might be good tool compounds to activate MSCs to inhibit B cells and suggest that our chemical approach might allow for improvements in the therapeutic efficacy of hMSCs in SLE.
Topics: Animals; Apoptosis; B-Lymphocytes; Cells, Cultured; Female; Humans; Lupus Erythematosus, Systemic; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C3H; Phorbol Esters; T-Lymphocytes
PubMed: 32929342
DOI: 10.7150/thno.46835 -
International Journal of Molecular... Nov 2012The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a "miracle tree", particularly as a source of alternate fuel. Various extracts of the plant... (Review)
Review
The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a "miracle tree", particularly as a source of alternate fuel. Various extracts of the plant have been reported to have insecticidal/acaricidal or molluscicidal/anthelminthic activities on vectors of medical or veterinary interest or on agricultural or non-agricultural pests. Among those extracts, the phorbol ester fraction from seed oil has been reported as a promising candidate for use as a plant-derived protectant of a variety of crops, from a range of pre-harvest and post-harvest insect pests. However, such extracts have not been widely used, despite the "boom" in the development of the crop in the tropics during recent years, and societal concerns about overuse of systemic chemical pesticides. There are many potential explanations to such a lack of use of Jatropha insecticidal extracts. On the one hand, the application of extracts potentially harmful to human health on stored food grain, might not be relevant. The problem of decomposition of phorbol esters and other compounds toxic to crop pests in the field needing further evaluation before such extracts can be widely used, may also be a partial explanation. High variability of phorbol ester content and hence of insecticidal activity among physic nut cultivars/ecotypes may be another. Phytotoxicity to crops may be further limitation. Apparent obstacles to a wider application of such extracts are the costs and problems involved with registration and legal approval. On the other hand, more studies should be conducted on molluscicidal activity on slugs and land snails which are major pests of crops, particularly in conservation agriculture systems. Further evaluation of toxicity to natural enemies of insect pests and studies on other beneficial insects such as pollinators are also needed.
Topics: Animals; Chemical Fractionation; Crops, Agricultural; Humans; Insect Control; Insecticides; Jatropha; Phorbol Esters; Plant Extracts; Plant Oils; Seeds
PubMed: 23203190
DOI: 10.3390/ijms131216157 -
The Biochemical Journal Jun 2013PKC (protein kinase C) has been in the limelight since the discovery three decades ago that it acts as a major receptor for the tumour-promoting phorbol esters. Phorbol... (Review)
Review
PKC (protein kinase C) has been in the limelight since the discovery three decades ago that it acts as a major receptor for the tumour-promoting phorbol esters. Phorbol esters, with their potent ability to activate two of the three classes of PKC isoenzymes, have remained the best pharmacological tool for directly modulating PKC activity. However, with the discovery of other phorbol ester-responsive proteins, the advent of various small-molecule and peptide modulators, and the need to distinguish isoenzyme-specific activity, the pharmacology of PKC has become increasingly complex. Not surprisingly, many of the compounds originally touted as direct modulators of PKC have subsequently been shown to hit many other cellular targets and, in some cases, not even directly modulate PKC. The complexities and reversals in PKC pharmacology have led to widespread confusion about the current status of the pharmacological tools available to control PKC activity. In the present review, we aim to clarify the cacophony in the literature regarding the current state of bona fide and discredited cellular PKC modulators, including activators, small-molecule inhibitors and peptides, and also address the use of genetically encoded reporters and of PKC mutants to measure the effects of these drugs on the spatiotemporal dynamics of signalling by specific isoenzymes.
Topics: Animals; Enzyme Activation; Humans; Isoenzymes; Ligands; Models, Molecular; Phorbol Esters; Protein Kinase C; Protein Kinase Inhibitors
PubMed: 23662807
DOI: 10.1042/BJ20130220 -
International Journal of Molecular... Mar 2016The Aquilaria malaccensis (Thymelaeaceae) tree is a source of precious fragrant resin, called agarwood, which is widely used in traditional medicines in East Asia...
The Aquilaria malaccensis (Thymelaeaceae) tree is a source of precious fragrant resin, called agarwood, which is widely used in traditional medicines in East Asia against diseases such as asthma. In our continuous search for active natural products, A. malaccensis seeds ethanolic extract demonstrated antiallergic effect with an IC50 value less than 1 µg/mL. Therefore, the present research aimed to purify and identify the antiallergic principle of A. malaccensis through a bioactivity-guided fractionation approach. We found that phorbol ester-rich fraction was responsible for the antiallergic activity of A. malaccensis seeds. One new active phorbol ester, 12-O-(2Z,4E,6E)-tetradeca-2,4,6-trienoylphorbol-13-acetate, aquimavitalin (1) was isolated. The structure of 1 was assigned by means of 1D and 2D NMR data and high-resolution mass spectrometry (HR-MS). Aquimavitalin (1) showed strong inhibitory activity in A23187- and antigen-induced degranulation assay with IC50 values of 1.7 and 11 nM, respectively, with a therapeutic index up to 71,000. The antiallergic activities of A. malaccensis seeds and aquimavitalin (1) have never been revealed before. The results indicated that A. malaccensis seeds and the pure compound have the potential for use in the treatment of allergy.
Topics: Animals; Anti-Allergic Agents; Cell Line, Tumor; Phorbol Esters; Plant Extracts; Rats; Seeds; Thymelaeaceae
PubMed: 27007372
DOI: 10.3390/ijms17030398 -
The Journal of Biological Chemistry Jul 1986A mixed micellar assay for the binding of phorbol-esters to protein kinase C was developed to investigate the specificity and stoichiometry of phospholipid cofactor...
A mixed micellar assay for the binding of phorbol-esters to protein kinase C was developed to investigate the specificity and stoichiometry of phospholipid cofactor dependence and oligomeric state of protein kinase C (Ca2+/phospholipid-dependent enzyme) required for phorbol ester binding. [3H]Phorbol dibutyrate was bound to protein kinase C in the presence of Triton X-100 mixed micelles containing 20 mol % phosphatidylserine (PS) in a calcium-dependent manner with a Kd of 5 X 10(-9) M. The [3H]phorbol dibutyrate X protein kinase C . Triton X-100 . PS mixed micellar complex eluted on a Sephacryl S-200 molecular sieve at an Mr of approximately 200,000; this demonstrates that monomeric protein kinase C binds phorbol dibutyrate. This conclusion was supported by molecular sieve chromatography of a similar complex where Triton X-100 was replaced with beta-octylglucoside. Phorbol dibutyrate activation of protein kinase C in Triton X-100/PS mixed micelles occurred and was dependent on calcium. The PS dependence of both phorbol ester activation and binding to protein kinase C lagged initially and then was highly cooperative. The minimal mole per cent PS required was strongly dependent on the concentration of phorbol dibutyrate or phorbol myristic acetate employed. Even at the highest concentration of phorbol ester tested, a minimum of 3 mol % PS was required; this indicates that approximately four molecules of PS are required. [3H]Phorbol dibutyrate binding was independent of micelle number at 20 mol % PS. The phospholipid dependencies of phorbol ester binding and activation were similar, with PS being the most effective; anionic phospholipids (cardiolipin, phosphatidic acid, and phosphatidylglycerol were less effective, whereas phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin did not support binding or activation. sn-1,2-Dioleoylglycerol displaced [3H]phorbol dibutyrate quantitatively and competitively. The data are discussed in relation to a molecular model of protein kinase C activation.
Topics: Animals; Calcium; Chromatography, Gel; Colloids; Enzyme Activation; Female; Macromolecular Substances; Micelles; Octoxynol; Phorbol 12,13-Dibutyrate; Phorbol Esters; Phosphatidylserines; Phospholipids; Polyethylene Glycols; Protein Kinase C; Rats
PubMed: 3459728
DOI: No ID Found -
Journal of Neurochemistry Mar 2008GN11 and GT1-7 are immortalized gonadotropin-releasing hormone-positive murine cell lines exhibiting the features of immature olfactory neurons and differentiated...
GN11 and GT1-7 are immortalized gonadotropin-releasing hormone-positive murine cell lines exhibiting the features of immature olfactory neurons and differentiated hypothalamic neurons, respectively. Using electron microscopy and biochemical assays (RT-PCR and immunoblotting) we determined the presence of numerous caveolae invaginations and of caveolin-1 and -2 mRNAs and proteins in GN11 cells, and their absence in GT1-7 cells. The lack of caveolins in GT1-7 cells might be due to the silencing of gene transcription caused by estrogen receptor alpha whose inhibitory activity in GN11 cells could be counter-balanced by co-expression of caveolin-permissive estrogen receptor beta. To test whether the unique expression of caveolins in GN11 cells is related to their immature state, we treated GN11 cells for 24-72 h with retinoic acid or phorbol ester. Both treatments led to neuronal differentiation of GN11 cells, as shown by emission of long neuritic processes, increased expression of growth cone-associated protein-43 and appearance of voltage-gated K+ and C2+ channel currents. Concurrently, caveolins 1 and 2, and estrogen receptor beta were down-regulated in differentiated GN11, whereas estrogen receptor alpha was unaffected by differentiation. We conclude that caveolin expression in GN11 neurons is down-regulated upon differentiation and up-regulated by estrogen receptor beta.
Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Calcium Channels; Caveolin 1; Caveolin 2; Cell Differentiation; Cell Line, Tumor; Down-Regulation; Estrogen Receptor alpha; Estrogen Receptor beta; Gene Expression; Gonadotropin-Releasing Hormone; Membrane Potentials; Mice; Neurons; Patch-Clamp Techniques; Phorbol Esters; Tretinoin
PubMed: 17988240
DOI: 10.1111/j.1471-4159.2007.05109.x -
The Journal of Biological Chemistry Sep 2002Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic...
Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic acid. In yeast two-hybrid screening, we unexpectedly found a self-association of the C-terminal part of DGKdelta containing a sterile alpha-motif (SAM) domain. We then bacterially expressed the SAM domain fused with maltose-binding protein and confirmed the formation of dimeric and tetrameric structures. Moreover, gel filtration and co-immunoprecipitation analyses demonstrated that DGKdelta formed homo-oligomeric structures in intact cells and that the SAM domain was critically involved in the oligomerization. Interestingly, phorbol ester stimulation induced dissociation of the oligomeric structures with concomitant phosphorylation of DGKdelta. Furthermore, we found that DGKdelta was translocated from cytoplasmic vesicles to the plasma membrane upon phorbol ester stimulation. In this case, DGKdelta mutants lacking the ability of self-association were localized at the plasma membranes even in the absence of phorbol ester. A protein kinase C inhibitor, staurosporine, blocked all of the effects of phorbol ester, i.e. oligomer dissociation, phosphorylation, and translocation. We confirmed that tumor-promoting phorbol esters did not directly bind to DGKdelta. The present studies demonstrated that the formation and dissociation of oligomers serve as the regulatory mechanisms of DGKdelta and that DGKdelta is a novel downstream effector of phorbol ester/protein kinase C signaling pathway.
Topics: Animals; Biopolymers; Blotting, Western; COS Cells; Chromatography, Gel; Diacylglycerol Kinase; Enzyme Activation; Phosphorylation; Precipitin Tests; Protein Transport; Subcellular Fractions; Tetradecanoylphorbol Acetate; Two-Hybrid System Techniques
PubMed: 12084710
DOI: 10.1074/jbc.M202035200 -
Cell Jan 2002Munc13-1 is a presynaptic protein with an essential role in synaptic vesicle priming. It contains a diacylglycerol (DAG)/beta phorbol ester binding C(1) domain and is a...
Munc13-1 is a presynaptic protein with an essential role in synaptic vesicle priming. It contains a diacylglycerol (DAG)/beta phorbol ester binding C(1) domain and is a potential target of the DAG second messenger pathway that may act in parallel with PKCs. Using genetically modified mice that express a DAG/beta phorbol ester binding-deficient Munc13-1(H567K) variant instead of the wild-type protein, we determined the relative contribution of PKCs and Munc13-1 to DAG/beta phorbol ester-dependent regulation of neurotransmitter release. We show that Munc13s are the main presynaptic DAG/beta phorbol ester receptors in hippocampal neurons. Modulation of Munc13-1 activity by second messengers via the DAG/beta phorbol ester binding C(1) domain is essential for use-dependent alterations of synaptic efficacy and survival.
Topics: Amino Acid Sequence; Animals; Base Sequence; Binding Sites; Cells, Cultured; Diglycerides; Gene Expression; Hippocampus; Intracellular Signaling Peptides and Proteins; Mice; Molecular Sequence Data; Mutagenesis; Nerve Tissue Proteins; Neurons; Phorbol Esters; Point Mutation; Protein Kinase C; Synapses; Synaptic Transmission
PubMed: 11792326
DOI: 10.1016/s0092-8674(01)00635-3 -
The Journal of Cell Biology Jan 1986Embryonic rat neurons cultured in defined medium, essentially in the absence of glia, were highly enriched in phorbol ester receptors. The neurons displayed a single...
Embryonic rat neurons cultured in defined medium, essentially in the absence of glia, were highly enriched in phorbol ester receptors. The neurons displayed a single class of phorbol 12,13-dibutyrate binding sites with a maximum binding capacity, after 10 d in culture, of 18.6 pmol/mg protein and an apparent dissociation constant of 7.1 nM. Phorbol ester binding sites were associated with protein kinase C, which represented a major protein kinase activity in primary neuronal cultures. Ca2+-phosphatidylserine-sensitive phosphorylation of endogenous substrates was more marked than that observed in the presence of cyclic AMP or Ca2+ and calmodulin. Phorbol ester receptors and protein kinase C levels were critically dependent on the culture age. Thus, about a 20-fold increase in binding sites occurred during the first week in culture and was accompanied by a corresponding increase in Ca2+-phosphatidylserine-sensitive protein phosphorylation in soluble neuronal extracts. These changes largely paralleled a similar rise in phorbol ester binding during fetal development in vivo. The apparent induction of phorbol ester receptors was specific relative to other cellular proteins and could be inhibited by cycloheximide or Actinomycin D. Phosphorylation of endogenous substrates in intact cultured neurons paralleled the age-dependent increase in protein kinase C. Furthermore, 32P incorporation into several major phosphoproteins was markedly augmented by treating the neuronal cultures with phorbol esters. Such phosphorylation events may provide a clue to the significance of protein kinase C in developing neurons.
Topics: Animals; Caenorhabditis elegans Proteins; Carrier Proteins; Cell Differentiation; Cell Survival; Cells, Cultured; Molecular Weight; Nerve Tissue Proteins; Neuroglia; Neurons; Phorbol Esters; Phosphorylation; Protein Kinase C; Rats; Receptors, Drug; Receptors, Immunologic
PubMed: 3941157
DOI: 10.1083/jcb.102.1.312 -
Hypertension Research : Official... Jun 1995The modulation of dopamine DA1 receptors of cultured rat renal arterial smooth muscle cells by phorbol ester, glucocorticoid and sodium chloride was studied. The extent...
The modulation of dopamine DA1 receptors of cultured rat renal arterial smooth muscle cells by phorbol ester, glucocorticoid and sodium chloride was studied. The extent of [3H]Sch-23390 binding to phorbol ester-treated cell was increased without any change in the dissociation constant (Kd). At a concentration of 10 nmol/l, the synthetic glucocorticoid dexamethasone increased maximum receptor binding (Bmax) but had no effect on the Kd. 100 mmol/l sodium chloride did not change Bmax, but increased the Kd for DA1 receptor. The production of cAMP in response to DA1 receptor stimulation was enhanced without any change of the adenylate cyclase activity. The glucocorticoid effect on DA1 of arterial smooth muscle cells became apparent after hours of incubation in the presence of the steroid and was significantly inhibited by cycloheximide (10 micrograms/ml) and by the glucocorticoid receptor antagonist RU-38486, indicating that the effect required protein synthesis through glucocorticoid receptors. Treatment of cells with 1 mumol/l dexamethasone for 24 h increased basal and DA1-stimulated adenylate cyclase activity. Basal adenylate cyclase was decreased by sodium chloride in a dose-dependent manner. These results suggest differential control of DA1 receptors on vascular smooth muscle cells by protein kinase C, glucocorticoid or sodium chloride.
Topics: Adenylyl Cyclases; Animals; Benzazepines; Binding, Competitive; Cyclic AMP; Dopamine Antagonists; Glucocorticoids; In Vitro Techniques; Kinetics; Muscle, Smooth, Vascular; Phorbol Esters; Rats; Rats, Wistar; Receptors, Dopamine D1; Sodium Chloride
PubMed: 8529070
DOI: 10.1291/hypres.18.supplementi_s29