1-oleoyl-2-acetylglycerol and hyperforin

Tetrahydrohyperforin (IDN5706) is a semi-synthetic compound derived from hyperforin (IDN5522) and is the main active principle of St. John's Wort. IDN5706 has shown numerous beneficial effects when administered to wild-type and double transgenic (APPswe/PSEN1ΔE9) mice that model Alzheimer's disease. However, its mechanism of action is currently unknown. Toward this end, we analysed field excitatory postsynaptic potentials (fEPSPs) in mouse hippocampal slices incubated with IDN5706 and in the presence of the TRPC3/6/7 activator 1-oleoyl-2-acetyl-sn-glycerol (OAG), the TRPC channel blocker SKF96365, and neurotoxic amyloid β-protein (Aβ) oligomers. To study spatial memory, Morris water maze (MWM) behavioural tests were conducted on wild-type mice treated with IDN5706 and SKF96365. In silico studies were conducted to predict a potential pharmacophore. IDN5706 and OAG had a similar stimulating effect on fEPSPs, which was inhibited by SKF96365. IDN5706 protected from reduced fEPSPs induced by Aβ oligomers. IDN5706 improved spatial memory in wild-type mice, an effect that was counteracted by co-administration of SKF96365. Our in silico studies suggest strong pharmacophore similarity of IDN5706 and other reported TRPC6 activators (IDN5522, OAG and Hyp9). We propose that the effect of IDN5706 is mediated through activation of the TRPC3/6/7 channel subfamily. The unveiling of the drug's mechanism of action is a necessary step toward the clinical use of IDN5706 in Alzheimer's disease.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Behavior, Animal; Binding Sites; Diglycerides; Excitatory Postsynaptic Potentials; Hippocampus; Imidazoles; In Vitro Techniques; Long-Term Potentiation; Male; Mice; Mice, Inbred C57BL; Molecular Docking Simulation; Neuroprotective Agents; Phloroglucinol; Protein Structure, Tertiary; Terpenes; TRPC Cation Channels

Expression of transient receptor potential canonical channels (TRPC) and the effects of transforming growth factor-β1 (TGF-β1) on Ca2+ signals and fibroblast proliferation were investigated in human cardiac fibroblasts. The conventional and quantitative real-time RT-PCR, western blot, immunocytochemical analysis, and intracellular Ca2+ concentration [Ca2+]i measurement were applied. Cell proliferation and cell cycle progression were assessed using MTT assays and fluorescence activated cell sorting. Human cardiac fibroblasts have the expression of TRPC1,3,4,6 mRNA and proteins. 1-oleoyl-2-acetyl-sn-glycerol (OAG) and thapsigargin induced extracellular Ca(2+)-mediated [Ca2+]i rise. siRNA for knock down of TRPC6 reduced OAG-induced Ca2+ entry. Hyperforin as well as angiotensin II (Ang II) induced Ca2+ entry. KB-R7943, a reverse-mode Na+/Ca2+ exchanger (NCX) inhibitor, and/or replacement of Na+ with NMDG+ inhibited thapsigargin-, OAG- and Ang II-induced Ca2+ entry. Treatment with TGF-β1 increased thapsigargin-, OAG- and Ang II-induced Ca2+ entry with an enhancement of TRPC1,6 protein expression, suppressed by KB-R7943. TGF-β1 and AngII promoted cell cycle progression from G0/G1 to S/G2/M and cell proliferation. A decrease of the extracellular Ca2+ and KB-R7943 suppressed it. Human cardiac fibroblasts contain several TRPC-mediated Ca2+ influx pathways, which activate the reverse-mode NCX. TGF-β1 enhances the Ca2+ influx pathways requiring Ca2+ signals for its effect on fibroblast proliferation.

Topics: Angiotensin II; Calcium; Calcium Signaling; Cell Cycle Checkpoints; Cell Line; Cell Proliferation; Diglycerides; Enzyme Inhibitors; Fibroblasts; Humans; Phloroglucinol; RNA Interference; RNA, Messenger; RNA, Small Interfering; Sodium-Calcium Exchanger; Terpenes; Thapsigargin; Thiourea; Transforming Growth Factor beta1; TRPC Cation Channels

We previously showed that, in vitro, hyperforin from St. John's wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B(4) formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.

Topics: Animals; Arachidonate 5-Lipoxygenase; Binding Sites; Bridged Bicyclo Compounds; Carrageenan; Cells, Cultured; Diglycerides; Humans; Hypericum; Leukotriene B4; Lipoxygenase Inhibitors; Male; MAP Kinase Signaling System; Microfilament Proteins; Neutrophils; Oxidation-Reduction; Phloroglucinol; Phospholipids; Pleurisy; Protein Structure, Tertiary; Protein Transport; Rats; Rats, Wistar; Terpenes; Tryptophan