Peripheral site acetylcholinesterase inhibitors targeting both inflammation and cholinergic dysfunction

Abstract

The design and study of two classes of noncompetitive acetylcholinesterase inhibitors (AChEIs) which also function as NSAID prodrugs are reported. The most potent AChEIs disclosed contain an aromatic alkyl-aryl linker between an NSAID and a lipophilic choline mimic and they inhibit acetylcholinesterase (AChE) in the submicromolar range. These agents have the therapeutic potential to dually target inflammation by releasing an NSAID in vivo and activating the cholinergic antiinflammatory pathway via cholinergic up-regulation.Pro-inflammatory cytokine up-regulation plays a role in the pathogenesis of a wide range of disorders including osteoarthritis, 1 psoriasis, 2 multiple sclerosis, 3 and other autoimmune disorders. 4 Despite decades of research, non-steroidal anti-inflammatory drugs (NSAIDs) are still one of the most commonly used, highly effective treatments for such disorders. However, since chronic NSAID-use often leads to gastrointestinal (GI) side effects, NSAID ester prodrugs have been explored to mask the acidic GI-irritating portion of the NSAID. 5 For conditions such as arthritis, topical NSAID prodrugs are particularly useful as their therapeutic action is localized, resulting in minimal systemic side effects. 6 Alternately, acetylcholinesterase inhibitors (AChEIs) have implications in the treatment of severe inflammation resulting from sepsis, 7 endotoxemia, 8 and rheumatoid arthritis, 9 as well as in the treatment of neuroinflammation associated with Alzheimer's disease [10][11][12] and Myasthenia Gravis. 13 The administration of CNS-active AChEIs such as galanthamine depletes systemic pro-inflammatory cytokines and ameliorates both central and peripheral inflammation. 8 AChEIs seem to suppress inflammation via the cholinergic anti-inflammatory pathway, a mechanism by which the vagus nerve of the CNS regulates the production and release of tumor necrosis factor and other cytokines. 14,15 *Corresponding author. Tel.: 1-610-758-3464; fax.: 1-610-758-3461; ndh0@lehigh.edu. † Current address: PTC Therapeutics, Inc., South Plainfield, NJ 07080-2449, USA ‡ Current address: Digestive Care, Inc., Bethlehem, PA 18017-7059, USA Supplementary data Synthetic procedures, physical characterization of compounds, in vitro assay methods and Lineweaver-Burk plots can be found in the online version of this article.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. (Figure 1). 18 The synthesis and evaluation of these compounds as anti-inflammatory and anticholinesterase agents for topical or oral administration are presented herein. NIH Public AccessAuthor Manuscript Bioor...

Therapeutic potential of a non-steroidal bifunctional anti-inflammatory and anti-cholinergic agent against skin injury induced by sulfur mustard

“…SM was obtained from Edgewood Chemical Biological Center and was chemically analyzed to be 99% pure. NDH 4338, was synthesized as previously reported (Young et al , 2010). …”

“…Indomethacin was chosen because it had, in a pre-treatment based study, been reported to display modest edema-suppression in rodents exposed to sulfur mustard (Casillas et al , 2000). Also, in an earlier publication from our laboratory using a post-treatment assay, Indomethacin ranked better than Diclofenac, Ibuprofen, and S-Naproxen when incorporated into a prodrug, dually targeting inflammation and cholinergic dysfunction (Young et al , 2012). …”

“…We selected 3,3-dimethyl-1-butanol because it has been reported to be a weak (Ki = 7.3 mM), reversible, noncompetitive inhibitor of AChE and can be incorporated into esters as a bioisostere for choline and activate the cholinergic anti-inflammatory pathway (Cohen et al , 1985). We have previously shown that although the 3,3-dimethylbutyl moiety does confer anticholinergic activity, the IC50's (as AChEIs) varied from 0.51 micromolar to >2000 micromolar depending on the particular NSAID to which the 3,3-dimethylbutyl piece is conjugated (Young et al , 2010). …”

“…In these experiments, we utilized a prodrug consisting of an NSAID (indomethacin) and an AChEI (3, 3-dimethyl-1-butanol) (Young et al , 2010). Indomethacin is tethered by ester and carbonate linkages to 3, 3-dimethyl-1-butanol, an anti-cholinergic choline bioisostere (Figure 1).…”

“…Indomethacin is tethered by ester and carbonate linkages to 3, 3-dimethyl-1-butanol, an anti-cholinergic choline bioisostere (Figure 1). This compound, referred to as NDH 4338, possesses anti-inflammatory activity and is an AChEI inhibitor (Young et al , 2010; Young et al , 2012). In previous studies using the mouse ear vesicant model we demonstrated that NDH 4338 mitigated skin inflammation induced by the half mustard vesicant, 2-chloroetheyl ethyl sulfide (CEES) and was shown to reduce edema by over 90%, suggesting its use as a countermeasure against SM-induced skin injury (Young et al , 2010; Young et al , 2012).…”