Lumir Hanus

Bio: Lumir Hanus is an academic researcher from Hebrew University of Jerusalem. The author has contributed to research in topics: Cannabinoid & Cannabinoid receptor. The author has an hindex of 40, co-authored 103 publications receiving 15210 citations. Previous affiliations of Lumir Hanus include Weizmann Institute of Science & Wolfson Medical Center.

Isolation and structure of a brain constituent that binds to the cannabinoid receptor

Abstract: Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.

Molecular targets for cannabidiol and its synthetic analogues: effect on vanilloid VR1 receptors and on the cellular uptake and enzymatic hydrolysis of anandamide.

Abstract: (−)-Cannabidiol (CBD) is a non-psychotropic component of Cannabis with possible therapeutic use as an anti-inflammatory drug. Little is known on the possible molecular targets of this compound. We investigated whether CBD and some of its derivatives interact with vanilloid receptor type 1 (VR1), the receptor for capsaicin, or with proteins that inactivate the endogenous cannabinoid, anandamide (AEA). CBD and its enantiomer, (+)-CBD, together with seven analogues, obtained by exchanging the C-7 methyl group of CBD with a hydroxy-methyl or a carboxyl function and/or the C-5′ pentyl group with a di-methyl-heptyl (DMH) group, were tested on: (a) VR1-mediated increase in cytosolic Ca2+ concentrations in cells over-expressing human VR1; (b) [14C]-AEA uptake by RBL-2H3 cells, which is facilitated by a selective membrane transporter; and (c) [14C]-AEA hydrolysis by rat brain membranes, which is catalysed by the fatty acid amide hydrolase. Both CBD and (+)-CBD, but not the other analogues, stimulated VR1 with EC50=3.2 – 3.5 μM, and with a maximal effect similar in efficacy to that of capsaicin, i.e. 67 – 70% of the effect obtained with ionomycin (4 μM). CBD (10 μM) desensitized VR1 to the action of capsaicin. The effects of maximal doses of the two compounds were not additive. (+)-5′-DMH-CBD and (+)-7-hydroxy-5′-DMH-CBD inhibited [14C]-AEA uptake (IC50=10.0 and 7.0 μM); the (−)-enantiomers were slightly less active (IC50=14.0 and 12.5 μM). CBD and (+)-CBD were also active (IC50=22.0 and 17.0 μM). CBD (IC50=27.5 μM), (+)-CBD (IC50=63.5 μM) and (−)-7-hydroxy-CBD (IC50=34 μM), but not the other analogues (IC50>100 μM), weakly inhibited [14C]-AEA hydrolysis. Only the (+)-isomers exhibited high affinity for CB1 and/or CB2 cannabinoid receptors. These findings suggest that VR1 receptors, or increased levels of endogenous AEA, might mediate some of the pharmacological effects of CBD and its analogues. In view of the facile high yield synthesis, and the weak affinity for CB1 and CB2 receptors, (−)-5′-DMH-CBD represents a valuable candidate for further investigation as inhibitor of AEA uptake and a possible new therapeutic agent. Keywords: Cannabinoid, endocannabinoid, vanilloid, receptors, FAAH, anandamide transporter Introduction Among the bioactive constituents of Cannabis sativa, (−)-cannabidiol (CBD, Figure 1) is one of those with the highest potential for therapeutic use (Mechoulam, 1999). Although the pharmacological properties of the other major Cannabis component, (−)-Δ9-tetrahydrocannabinol (THC), have been more thoroughly investigated (Mechoulam, 1999; Pertwee, 1999, for reviews), THC, unlike CBD, exhibits potent psychotropic effects, which have complicated the full assessment of its therapeutic potential. Little is known of the molecular mechanism(s) of action of CBD, which, unlike THC, has very little affinity for either cannabinoid receptor subtypes identified so far, the CB1 and CB2 receptors (Pertwee, 1997, for review). Recent studies, together with the earlier finding of the anti anxiety (Guimaraes et al., 1994), neuro-protective and anti-convulsive activity of CBD and some of its analogues (Consroe et al., 1981; Martin et al., 1987), indicate that CBD may also exert cyto-protective effects by inhibiting the release of inflammatory cytokines from blood cells (Srivastava et al., 1998; Malfait et al., 2000), thus producing an anti-inflammatory action, for example against rheumatoid arthritis (Malfait et al., 2000). These effects of CBD may be due to its anti-oxidant properties (Hampson et al., 1998), to its direct interaction with cytochrome p450-enzymes (Bornheim & Correia, 1989) and other enzymes of the ‘arachidonate cascade' (Burstein et al., 1985), or to an action at a specific receptor. Recent studies have investigated whether CBD interacts with proteins of the ‘endocannabinoid signalling system' other than the CB1/CB2 receptors. These proteins are: (i) fatty acid amide hydrolase (FAAH) (Cravatt et al., 1996), the intracellular enzyme catalysing the hydrolysis of the endogenous cannabinoid ligand, anandamide (arachidonoylethanolamide, AEA) (Ueda et al., 2000, for review); and (ii) the ‘anandamide membrane transporter' (AMT) (Di Marzo et al., 1994), which facilitates the transport of AEA across the cell membrane and, subsequently, its intracellular degradation (Hillard & Jarrahian, 2000, for review). It was found that CBD inhibits both AEA hydrolysis by FAAH-containing membrane preparations (Watanabe et al., 1996), and AEA uptake by RBL – 2H3 cells via the AMT (Rakhshan et al., 2000). Although these effects were observed at high μM concentrations, these findings raised the possibility that some of the pharmacological actions of CBD might be due to inhibition of AEA degradation, with subsequent enhancement of the endogenous levels of this mediator, for which neuroprotective (Hansen et al., 1998) and anti-inflammatory (Di Marzo et al., 2000a) properties have been previously suggested. Figure 1 Chemical structures of cannabidiol and capsaicin. The numbering for cannabidiol carbon atoms, and a possible cannabidiol-like conformation for capsaicin are shown. Many pharmacological activities of CBD have been established only in vivo, hence some of them may be due to CBD metabolites. The metabolism of CBD is well established. The primary step is hydroxylation on C-7, leading to (−)-7-hydroxy-CBD, followed by further oxidation to (−)-7-carboxy-CBD (Agurell et al., 1986). Although the metabolism of the dimethyl-heptyl homologue of CBD and of the (+) enantiomer of CBD has not been investigated, it is reasonable to assume that it follows the same pathways. Hence we prepared these CBD metabolites, their DMH homologues and some of the respective metabolites in the unnatural (+) series. In particular, in the present study we have examined whether the stereochemistry and the presence of certain chemical groups on the C-5′ and C-1 of CBD affect its capability of influencing AEA inactivation via the AMT and FAAH. Furthermore, we have addressed the question of the possible molecular transducer of CBD by studying the possibility that this natural compound, its (+)-enantiomer and some of its synthetic analogues, interact with another proposed target for AEA, i.e. the vanilloid receptor type 1 (VR1) for capsaicin (Holzer, 1991, Figure 1). This protein is a ligand-, heat- and proton-activated non-specific cation channel acting as a molecular integrator of nociceptive stimuli (Tominaga et al., 1998). Recently, it was discovered that AEA is a full, albeit weak, VR1 agonist (Zygmunt et al., 1999; Smart et al., 2000) and that synthetic capsaicin analogues can interact with either CB1 receptors or the AMT, or both (Di Marzo et al., 1998). Thus, there appears to be some overlap between the ligand recognition properties of VR1 and CB1 receptors and, in particular, of VR1 and the AMT (de petrocellis et al., 2000; Szallasi & Di Marzo, 2000). Although VR1, via the release of inflammatory and algesic peptides, is involved in inflammatory hyperalgesia (Davis et al., 2000; Caterina et al., 2000), the stimulation of this receptor by capsaicin and some of its analogues leads to rapid desensitization, with subsequent paradoxical analgesic and anti-inflammatory effects (Holzer, 1991; Szallasi & Blumberg, 1999). As a consequence of this tachyphylactic effect, capsaicin, like CBD, has been used to treat arthritis (Lorton et al., 2000) and convulsions (Dib & Falchi, 1996). We report data suggesting that VR1 is a possible molecular target for CBD, and that inhibitors of the AMT can be developed by chemical modification of this natural product.

2-Arachidonyl glyceryl ether, an endogenous agonist of the cannabinoid CB1 receptor

Abstract: Two types of endogenous cannabinoid-receptor agonists have been identified thus far. They are the ethanolamides of polyunsaturated fatty acids—arachidonoyl ethanolamide (anandamide) is the best known compound in the amide series—and 2-arachidonoyl glycerol, the only known endocannabinoid in the ester series. We report now an example of a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), isolated from porcine brain. The structure of noladin ether was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by comparison with a synthetic sample. It binds to the CB1 cannabinoid receptor (Ki = 21.2 ± 0.5 nM) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds weakly to the CB2 receptor (Ki > 3 μM).

An endogenous cannabinoid (2-AG) is neuroprotective after brain injury

Abstract: Traumatic brain injury triggers the accumulation of harmful mediators that may lead to secondary damage. Protective mechanisms to attenuate damage are also set in motion. 2-Arachidonoyl glycerol (2-AG) is an endogenous cannabinoid, identified both in the periphery and in the brain, but its physiological roles have been only partially clarified. Here we show that, after injury to the mouse brain, 2-AG may have a neuroprotective role in which the cannabinoid system is involved. After closed head injury (CHI) in mice, the level of endogenous 2-AG was significantly elevated. We administered synthetic 2-AG to mice after CHI and found significant reduction of brain oedema, better clinical recovery, reduced infarct volume and reduced hippocampal cell death compared with controls. When 2-AG was administered together with additional inactive 2-acyl-glycerols that are normally present in the brain, functional recovery was significantly enhanced. The beneficial effect of 2-AG was dose-dependently attenuated by SR-141761A, an antagonist of the CB1 cannabinoid receptor.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Molecular characterization of a peripheral receptor for cannabinoids

Abstract: THE major active ingredient of marijuana, Δ9-tetrahydrocannabi-nol (Δ9-THC), has been used as a psychoactive agent for thousands of years. Marijuana, and Δ9-THC, also exert a wide range of other effects including analgesia, anti-inflammation, immunosuppression, anticonvulsion, alleviation of intraocular pressure in glaucoma, and attenuation of vomiting1. The clinical application of cannabinoids has, however, been limited by their psychoactive effects, and this has led to interest in the biochemical bases of their action. Progress stemmed initially from the synthesis of potent derivatives of δ9-THC4,5, and more recently from the cloning of a gene encoding a G-protein-coupled receptor for cannabinoids6. This receptor is expressed in the brain but not in the periphery, except for a low level in testes. It has been proposed that the non-psychoactive effects of cannabinoids are either mediated centrally or through direct interaction with other, non-receptor proteins1,7,8. Here we report the cloning of a receptor for cannabinoids that is not expressed in the brain but rather in macrophages in the marginal zone of spleen.

International Union of Pharmacology. XXVII. Classification of Cannabinoid Receptors

Abstract: Two types of cannabinoid receptor have been discovered so far, CB(1) (2.1: CBD:1:CB1:), cloned in 1990, and CB(2) (2.1:CBD:2:CB2:), cloned in 1993. Distinction between these receptors is based on differences in their predicted amino acid sequence, signaling mechanisms, tissue distribution, and sensitivity to certain potent agonists and antagonists that show marked selectivity for one or the other receptor type. Cannabinoid receptors CB(1) and CB(2) exhibit 48% amino acid sequence identity. Both receptor types are coupled through G proteins to adenylyl cyclase and mitogen-activated protein kinase. CB(1) receptors are also coupled through G proteins to several types of calcium and potassium channels. These receptors exist primarily on central and peripheral neurons, one of their functions being to inhibit neurotransmitter release. Indeed, endogenous CB(1) agonists probably serve as retrograde synaptic messengers. CB(2) receptors are present mainly on immune cells. Such cells also express CB(1) receptors, albeit to a lesser extent, with both receptor types exerting a broad spectrum of immune effects that includes modulation of cytokine release. Of several endogenous agonists for cannabinoid receptors identified thus far, the most notable are arachidonoylethanolamide, 2-arachidonoylglycerol, and 2-arachidonylglyceryl ether. It is unclear whether these eicosanoid molecules are the only, or primary, endogenous agonists. Hence, we consider it premature to rename cannabinoid receptors after an endogenous agonist as is recommended by the International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. Although pharmacological evidence for the existence of additional types of cannabinoid receptor is emerging, other kinds of supporting evidence are still lacking.