Phenyl carbamoyl analogues of physostigmine-esrine were developed to provide longer acting and better tolerated Alzheimer's disease treatment. Posiphen (enantiomer of phenserine: ANVS401 (+)-phenserine) is under investigation in clinical trial NCT02925650 (Early Alzheimer's Disease) Posiphen does not inhibit AChE or BChE, but its major and minor metabolites (+)-N1-norPosiphen and (+)-N1,N8-bisnorPosiphen, respectively, possessed modest AChE inhibitory activity.
1 moreTitle: Synthesis of the Alzheimer Drug Posiphen into its Primary Metabolic Products (+)-N1-norPosiphen, (+)-N8-norPosiphen and (+)-N1, N8-bisnorPosiphen, their Inhibition of Amyloid Precursor Protein, alpha -Synuclein Synthesis, Interleukin-1beta Release, and Cholinergic Action Yu QS, Reale M, Kamal MA, Holloway HW, Luo W, Sambamurti K, Ray B, Lahiri DK, Rogers JT, Greig NH Ref: Antiinflamm Antiallergy Agents Med Chem, 12:117, 2013 : PubMed
A major pathological hallmark of Alzheimer disease (AD) is the appearance in the brain of senile plaques that are primarily composed of aggregated forms of beta-amyloid peptide (Abeta) that derive from amyloid precursor protein (APP). Posiphen (1) tartrate is an experimental AD drug in current clinical trials that reduces Abeta levels by lowering the rate of APP synthesis without toxicity. To support the clinical development of Posiphen (1) and elucidate its efficacy, its three major metabolic products, (+)-N1-norPosiphen (15), (+)-N8-norPosiphen (17) and (+)-N1, N8-bisnorPosiphen (11), were required in high chemical and optical purity. The efficient transformation of Posiphen (1) into these metabolic products, 15, 17 and 11, is described. The biological activity of these metabolites together with Posiphen (1) and its enantiomer, the AD drug candidate (-)-phenserine (2), was assessed against APP,alpha-synuclein and classical cholinergic targets. All the compounds potently inhibited the generation of APP and alpha-synuclein in neuronal cultures. In contrast, metabolites 11 and 15, and (-)-phenserine (2) but not Posiphen (1) or 17, possessed acetyl cholinesterase inhibitory action and no compounds bound either nicotinic or muscarinic receptors. As Posiphen (1) lowered CSF markers of inflammation in a recent clinical trial, the actions of 1 and 2 on proinflammatory cytokine interleukin (IL)-1beta release human peripheral blood mononuclear cells was evaluated, and found to be potently inhibited by both agents.
There is compelling support for limiting expression of alpha-synuclein (alpha-syn) in the brains of Parkinson's disease (PD) patients. An increase of SNCA gene copy number can genetically cause familial PD where increased dose of this pathogenic protein correlates with severity of symptoms (triplication of the SNCA gene causes dementia in PD patients). Gene promoter polymorphisms were shown to increase alpha-synuclein expression as a risk for PD. Cholinesterase inhibitors can clinically slow cognitive decline in the later stages of PD etiology similar to their widespread use in Alzheimer's disease (AD). Pertinent to this, we identified that the well-tolerated anticholinesterase, phenserine, blocked neural SNCA mRNA translation and tested for targeting via its 5'untranslated region (5'UTR) in a manner similar to its action to limit the expression of the AD-specific amyloid precursor protein (APP). Posiphen, its better-tolerated (+) enantiomer (devoid of anticholinesterase action), repressed neural alpha-synuclein translation. Primary metabolic analogs of posiphen were, likewise, characterized using primary fetal neurons grown ex vivo from the brains of Parkinson's transgenic mice expressing the human SNCA gene.
Major characteristics of Alzheimer's disease (AD) are synaptic loss, cholinergic dysfunction, and abnormal protein depositions in the brain. The amyloid beta-peptide (Abeta), a proteolytic fragment of amyloid beta precursor protein (APP), aggregates to form neuritic plaques and has a causative role in AD. A present focus of AD research is to develop safe Abeta-lowering drugs. A selective acetylcholinesterase inhibitor, phenserine, in current human trials lowers both APP and Abeta. Phenserine is dose-limited in animals by its cholinergic actions; its cholinergically inactive enantiomer, posiphen (+)-[phenserine], was assessed. In cultured human neuroblastoma cells, posiphen, like phenserine, dose- and time-dependently lowered APP and Abeta levels by reducing the APP synthesis rate. This action translated to an in vivo system. Posiphen administration to mice (7.5-75 mg/kg daily, 21 consecutive days) significantly decreased levels of total APP (tissue mass-adjusted) in a dose-dependent manner. Abeta40 and Abeta42 levels were significantly lowered by posiphen (> or =15 mg/kg) compared with controls. The activities of alpha-, beta-, and gamma-secretases were assessed in the same brain samples, and beta-secretase activity was significantly reduced. Posiphen, like phenserine, can lower Abeta via multiple mechanisms and represents an interesting drug candidate for AD treatment.
Acetylcholinesterase (AChE) inhibitors have protective and anti-inflammatory actions against brain injury, mediated by nicotinic alpha7 cholinergic receptor activation. The use of AChE inhibitors in patients is limited by systemic cholinergic side effects. Posiphen, a stereoisomer of the AChE inhibitor Phenserine, lacks AChE inhibitor activity. The purpose of this study is to determine the protective effect of Posiphen in cellular and animal models of stroke. Both Posiphen and Phenserine reduced glutamate-mediated neuronal loss in co-cultures of primary cortical cells and microglia. Phenserine-, but not Posiphen-, mediated neuroprotection was diminished by the nicotinic alpha7 receptor antagonist methyllycaconitine. Posiphen antagonized NMDA-mediated Ca(++) influx, thapsigargin-mediated neuronal loss and ER stress in cultured cells. Early post-treatment with Posiphen reduced ER stress signals, IBA1 immunoreactivity, TUNEL and infarction in the ischemic cortex, as well as neurological deficits in stroke rats. These findings indicate that Posiphen is neuroprotective against stroke through regulating Ca(++)i and ER stress.
Title: Synthesis of the Alzheimer Drug Posiphen into its Primary Metabolic Products (+)-N1-norPosiphen, (+)-N8-norPosiphen and (+)-N1, N8-bisnorPosiphen, their Inhibition of Amyloid Precursor Protein, alpha -Synuclein Synthesis, Interleukin-1beta Release, and Cholinergic Action Yu QS, Reale M, Kamal MA, Holloway HW, Luo W, Sambamurti K, Ray B, Lahiri DK, Rogers JT, Greig NH Ref: Antiinflamm Antiallergy Agents Med Chem, 12:117, 2013 : PubMed
A major pathological hallmark of Alzheimer disease (AD) is the appearance in the brain of senile plaques that are primarily composed of aggregated forms of beta-amyloid peptide (Abeta) that derive from amyloid precursor protein (APP). Posiphen (1) tartrate is an experimental AD drug in current clinical trials that reduces Abeta levels by lowering the rate of APP synthesis without toxicity. To support the clinical development of Posiphen (1) and elucidate its efficacy, its three major metabolic products, (+)-N1-norPosiphen (15), (+)-N8-norPosiphen (17) and (+)-N1, N8-bisnorPosiphen (11), were required in high chemical and optical purity. The efficient transformation of Posiphen (1) into these metabolic products, 15, 17 and 11, is described. The biological activity of these metabolites together with Posiphen (1) and its enantiomer, the AD drug candidate (-)-phenserine (2), was assessed against APP,alpha-synuclein and classical cholinergic targets. All the compounds potently inhibited the generation of APP and alpha-synuclein in neuronal cultures. In contrast, metabolites 11 and 15, and (-)-phenserine (2) but not Posiphen (1) or 17, possessed acetyl cholinesterase inhibitory action and no compounds bound either nicotinic or muscarinic receptors. As Posiphen (1) lowered CSF markers of inflammation in a recent clinical trial, the actions of 1 and 2 on proinflammatory cytokine interleukin (IL)-1beta release human peripheral blood mononuclear cells was evaluated, and found to be potently inhibited by both agents.
There is compelling support for limiting expression of alpha-synuclein (alpha-syn) in the brains of Parkinson's disease (PD) patients. An increase of SNCA gene copy number can genetically cause familial PD where increased dose of this pathogenic protein correlates with severity of symptoms (triplication of the SNCA gene causes dementia in PD patients). Gene promoter polymorphisms were shown to increase alpha-synuclein expression as a risk for PD. Cholinesterase inhibitors can clinically slow cognitive decline in the later stages of PD etiology similar to their widespread use in Alzheimer's disease (AD). Pertinent to this, we identified that the well-tolerated anticholinesterase, phenserine, blocked neural SNCA mRNA translation and tested for targeting via its 5'untranslated region (5'UTR) in a manner similar to its action to limit the expression of the AD-specific amyloid precursor protein (APP). Posiphen, its better-tolerated (+) enantiomer (devoid of anticholinesterase action), repressed neural alpha-synuclein translation. Primary metabolic analogs of posiphen were, likewise, characterized using primary fetal neurons grown ex vivo from the brains of Parkinson's transgenic mice expressing the human SNCA gene.
Major characteristics of Alzheimer's disease (AD) are synaptic loss, cholinergic dysfunction, and abnormal protein depositions in the brain. The amyloid beta-peptide (Abeta), a proteolytic fragment of amyloid beta precursor protein (APP), aggregates to form neuritic plaques and has a causative role in AD. A present focus of AD research is to develop safe Abeta-lowering drugs. A selective acetylcholinesterase inhibitor, phenserine, in current human trials lowers both APP and Abeta. Phenserine is dose-limited in animals by its cholinergic actions; its cholinergically inactive enantiomer, posiphen (+)-[phenserine], was assessed. In cultured human neuroblastoma cells, posiphen, like phenserine, dose- and time-dependently lowered APP and Abeta levels by reducing the APP synthesis rate. This action translated to an in vivo system. Posiphen administration to mice (7.5-75 mg/kg daily, 21 consecutive days) significantly decreased levels of total APP (tissue mass-adjusted) in a dose-dependent manner. Abeta40 and Abeta42 levels were significantly lowered by posiphen (> or =15 mg/kg) compared with controls. The activities of alpha-, beta-, and gamma-secretases were assessed in the same brain samples, and beta-secretase activity was significantly reduced. Posiphen, like phenserine, can lower Abeta via multiple mechanisms and represents an interesting drug candidate for AD treatment.
