Effects of a verbenachalcone derivative on neurite outgrowth, inhibition of caspase induction and gene expression

The role of chalcones: helichrysetin, xanthohumol, and flavokawin-C in promoting neurite outgrowth in PC12 Adh cells

Chalcones are a group of compounds widely distributed in plant kingdom. The aim of this study was to assess the neurite outgrowth stimulatory activity of selected chalcones, namely helichrysetin, xanthohumol and flavokawin-C. Using adherent rat pheochromocytoma (PC12 Adh) cells, the chalcones were subjected to neurite outgrowth assay and the extracellular nerve growth factor (NGF) levels were determined. Xanthohumol (10 μg/mL) displayed the highest (p < 0.05) percentage of neurite-bearing PC12 Adh cells and the highest (p < 0.05) NGF level in the culture medium of xanthohumol-treated cells. While, helichrysetin induced a moderately high numbers of neurite-bearing cells, flavokawin-C did not stimulate neurite outgrowth. This work supports the potential use of xanthohumol as a potential neuroactive compound to stimulate neurite outgrowth.

The cholinergic system, sigma-1 receptors and cognition

This article provides an overview of present knowledge regarding the relationship between the cholinergic system and sigma-1 receptors, and discusses potential applications of sigma-1 receptor agonists in the treatment of memory deficits and cognitive disorders. Sigma-1 receptors, initially considered as a subtype of the opioid family, are unique ligand-regulated molecular chaperones in the endoplasmatic reticulum playing a modulatory role in intracellular calcium signaling and in the activity of several neurotransmitter systems, particularly the cholinergic and glutamatergic pathways. Several central nervous system (CNS) drugs show high to moderate affinities for sigma-1 receptors, including acetylcholinesterase inhibitors (donepezil), antipsychotics (haloperidol, rimcazole), selective serotonin reuptake inhibitors (fluvoxamine, sertraline) and monoamine oxidase inhibitors (clorgyline). These compounds can influence cognitive functions both via their primary targets and by activating sigma-1 receptors in the CNS. Sigma-1 agonists show powerful anti-amnesic and neuroprotective effects in a large variety of animal models of cognitive dysfunction involving, among others (i) pharmacologic target blockade (with muscarinic or NMDA receptor antagonists or p-chloroamphetamine); (ii) selective lesioning of cholinergic neurons; (iii) CNS administration of β-amyloid peptides; (iv) aging-induced memory loss, both in normal and senescent-accelerated rodents; (v) neurodegeneration induced by toxic compounds (CO, trimethyltin, cocaine), and (vi) prenatal restraint stress.

Microwave-assisted synthesis of 4-chloro-N-(naphthalen-1-ylmethyl)-5-(3-(piperazin-1-yl)phenoxy)thiophene-2-sulfonamide (B-355252): a new potentiator of Nerve Growth Factor (NGF)-induced neurite outgrowth

The synthesis of 4-chloro-N-(naphthalen-1-ylmethyl)-5-(3-(piperazin-1-yl)phenoxy)thiophene-2-sulfonamide (B-355252) using a MW-assisted nucleophilic aromatic substitution (S(N)Ar) reaction will be discussed. Utilization of this method allowed for the rapid generation of B-355252 heteroaryl ether core structure in the presence of cesium carbonate in dimethylformamide or tripotassium phosphate in N-methyl-2-pyrrolidone in 94% yield. Evaluation of B-355252 enhancement of nerve growth factor's ability to stimulate neurite outgrowths was determined using NS-1 cells.

A synthetic analog of verbenachalcone potentiates NGF-induced neurite outgrowth and enhances cell survival in neuronal cell models

This study uses NeuroScreen-1 (NS-1) cells, a derivative of pheochromocytoma (PC12) cells, to examine neurite outgrowth induced by a novel synthetic verbenachalcone derivative, DSRB20-022 (C22). We treated NS-1 cells with varying concentrations of C22 in the presence of 2ng/mL nerve growth factor (NGF). A dose-dependent effect of C22 was observed at concentrations of 2microM and above, resulting in significant enhancement of NGF-dependent neurite outgrowth in NS-1 cells. C22 did not exhibit neuritogenic activity in the absence of NGF, but promoted a concentration-dependent increase in neurite-bearing cells without inducing cytotoxicity. Cell viability assays showed that C22 and the parent compound verbenachalcone (VC) are neuroprotective and enhanced survival of NS-1, PC12, and the murine neuro-2A (N2a) cell lines under conditions of serum deprivation. The results show that augmentation of NGF-induced neurite outgrowth by C22 in NS-1 was dependent on MAP kinase. Furthermore, the neuroprotective function of C22 and VC was accompanied by suppression of caspase-3/7 activation. However, C22 and VC exerted their antagonistic effects on caspase-3/7 activation through potentially different mechanisms of action.

Effect of scoparone on neurite outgrowth in PC12 cells

The neurite outgrowth-promoting effects of scoparone isolated from the stem bark of Liriodendron tulipifera were investigated in PC12 cells. At a concentration of 200 microM, scoparone markedly induced neurite outgrowth from PC12 cells. Scoparone at 200 microM also enhanced the outgrowth of neurites from cells in the presence of nerve growth factor (NGF, 2 ng/ml). The levels of intracellular cyclic AMP and concentration of Ca2+ were also increased by 200 microM scoparone. In addition, scoparone at 200 microM increased the activities of extracellular signal-regulated protein kinase (ERK), cyclic AMP-dependent protein kinase (PKA), protein kinase C (PKC) and Ca2+/calmodulin kinase II (CaMK II). However, scoparone-induced neurite outgrowth was blocked by a mitogen-activated protein kinase inhibitor (U0126), a PKA inhibitor (H89), a PKC inhibitor (GF109203X) and a CaMK II inhibitor (KN62). These kinase inhibitors also reduced the scoparone-induced neurite outgrowth associated with NGF. These results suggest that scoparone can induce neurite outgrowth by stimulating the upstream steps of ERK, PKA, PKC and CaMK II in PC12 cells.

An update on the development of drugs for neuropsychiatric disorders: focusing on the sigma 1 receptor ligand

The sigma1 receptor is an intracellular molecule that shares no homology with any mammalian proteins. sigma1 receptors normally localize at the endoplasmic reticulum and regulate a variety of signal transductions including intracellular Ca2+ dynamics and neurotrophic factor signaling. In the brain, sigma1 receptors are known to regulate the activity of diverse ion channels via protein-protein interactions. Accumulated evidences strongly indicate that the activation/upregulation of sigma1 receptors promotes the neuronal differentiation as well as a robust antiapoptotic action. In animals, sigma1 receptor agonists exhibit an antidepressant-like action. Furthermore, the agonists enhanced neuronal survival eventhough they were administered several hours after a brain ischemia. Thus, primary clinical targets of sigma1 receptor ligands are proposed to include stroke, neurodegenerative disorders and depression. Ligands for the sigma1 receptor may constitute a new class of therapeutic drugs targeting an endoplasmic reticular protein.

Synthesis of verbenachalcone congeners and their biological assessment against activation of the NGF-mediated neurite outgrowth of PC12D cells' activity

Synthesis of the verbenachalcone derivatives 3-5 involving littorachalcone 2 from diaryl ether 7 enabled an SAR study of enhancement activity against the NGF-mediated neurite outgrowth from PC12D cells. Littorachalcone 2 and o-deoxyverbenachalcone 5 showed similar activity to that of verbenachalcone 1.