Evaluation of 3D-Printed Solid Microneedles Coated with Electrosprayed Polymeric Nanoparticles for Simultaneous Delivery of Rivastigmine and N-Acetyl Cysteine.

In the current study, coated microneedle arrays were fabricated by means of digital light processing (DLP) printing. Three different shapes were designed, printed, and coated with PLGA particles containing two different actives. Rivastigmine (RIV) and N-acetyl-cysteine (NAC) were coformulated via electrohydrodynamic atomization (EHDA), and they were incorporated into the PLGA particles. The two actives are administered as a combined therapy for Alzheimer's disease. The printed arrays were evaluated regarding their ability to penetrate skin and their mechanical properties. Optical microscopy and scanning electron microscopy (SEM) were employed to further characterize the microneedle structure. Confocal laser microscopy studies were conducted to construct 3D imaging of the coating and to simulate the diffusion of the particles through artificial skin samples. Permeation studies were performed to investigate the transport of the drugs across human skin ex vivo. Subsequently, a series of tape strippings were performed in an attempt to examine the deposition of the APIs on and within the skin. Light microscopy and histological studies revealed no drastic effects on the membrane integrity of the stratum corneum. Finally, the cytocompatibility of the microneedles and their precursors was evaluated by measuring cell viability (MTT assay and live/dead staining) and membrane damages followed by LDH release.

Homocysteine May Decrease Glucose Uptake and Alter the Akt/GSK3ß/GLUT1 Signaling Pathway in Hippocampal Slices: Neuroprotective Effects of Rivastigmine and Ibuprofen.

Homocysteine (Hcy) is a risk factor for neurodegenerative diseases, such as Alzheimer's Disease, and is related to cellular and tissue damage. In the present study, we verified the effect of Hcy on neurochemical parameters (redox homeostasis, neuronal excitability, glucose, and lactate levels) and the Serine/Threonine kinase B (Akt), Glucose synthase kinase-3ß (GSK3ß) and Glucose transporter 1 (GLUT1) signaling pathway in hippocampal slices, as well as the neuroprotective effects of ibuprofen and rivastigmine alone or in combination in such effects. Male Wistar rats (90 days old) were euthanized and the brains were dissected. The hippocampus slices were pre-treated for 30 min [saline medium or Hcy (30 µM)], then the other treatments were added to the medium for another 30 min [ibuprofen, rivastigmine, or ibuprofen + rivastigmine]. The dichlorofluorescein formed, nitrite and Na+, K+-ATPase activity was increased by Hcy at 30 µM. Ibuprofen reduced dichlorofluorescein formation and attenuated the effect of Hcy. The reduced glutathione content was reduced by Hcy. Treatments with ibuprofen and Hcy + ibuprofen increased reduced glutathione. Hcy at 30 µM caused a decrease in hippocampal glucose uptake and GLUT1 expression, and an increase in Glial Fibrillary Acidic Protein-protein expression. Phosphorylated GSK3ß and Akt levels were reduced by Hcy (30 µM) and co-treatment with Hcy + rivastigmine + ibuprofen reversed these effects. Hcy toxicity on glucose metabolism can promote neurological damage. The combination of treatment with rivastigmine + ibuprofen attenuated such effects, probably by regulating the Akt/GSK3ß/GLUT1 signaling pathway. Reversal of Hcy cellular damage by these compounds may be a potential neuroprotective strategy for brain damage.

Antidementia medication acetylcholinesterase inhibitors have therapeutic benefits on osteoporotic bone by attenuating osteoclastogenesis and bone resorption.

This study was designed to determine whether the use of acetylcholinesterase inhibitors (AChEIs), a group of drugs that stimulate acetylcholine receptors and are used to treat Alzheimer's disease (AD), is associated with osteoporosis protection and inhibition of osteoclast differentiation and function. Firstly, we examined the effects of AChEIs on RANKL-induced osteoclast differentiation and function with osteoclastogenesis and bone resorption assays. Next, we investigated the impacts of AChEIs on RANKL-induced nuclear factor κB and NFATc1 activation and expression of osteoclast marker proteins CA-2, CTSK and NFATc1, and dissected the MAPK signaling in osteoclasts in vitro by using luciferase assay and Western blot. Finally, we assessed the in vivo efficacy of AChEIs using an ovariectomy-induced osteoporosis mouse model, which was analyzed using microcomputed tomography, in vivo osteoclast and osteoblast parameters were assessed using histomorphometry. We found that Donepezil and Rivastigmine inhibited RANKL-induced osteoclastogenesis and impaired osteoclastic bone resorption. Moreover, AChEIs reduced the RANKL-induced transcription of Nfatc1, and expression of osteoclast marker genes to varying degrees (mainly Donepezil and Rivastigmine but not Galantamine). Furthermore, AChEIs variably inhibited RANKL-induced MAPK signaling accompanied by downregulation of AChE transcription. Finally, AChEIs protected against OVX-induced bone loss mainly by inhibiting osteoclast activity. Taken together, AChEIs (mainly Donepezil and Rivastigmine) exerted a positive effect on bone protection by inhibiting osteoclast function through MAPK and NFATc1 signaling pathways through downregulating AChE. Our findings have important clinical implications that elderly patients with dementia who are at risk of developing osteoporosis may potentially benefit from therapy with the AChEI drugs. Our study may influence drug choice in those patients with both AD and osteoporosis.

Rivastigmine-Benzimidazole Hybrids as Promising Multitarget Metal-Modulating Compounds for Potential Treatment of Neurodegenerative Diseases.

With the goal of combating the multi-faceted Alzheimer's disease (AD), a series of Rivastigmine-Benzimidazole (RIV-BIM) hybrids was recently reported by us as multitarget-directed ligands, thanks to their capacity to tackle important hallmarks of AD. In particular, they exhibited antioxidant activity, acted as cholinesterase inhibitors, and inhibited amyloid-ß (Aß) aggregation. Herein, we moved forward in this project, studying their ability to chelate redox-active biometal ions, Cu(II) and Fe(III), with widely recognized roles in the generation of oxidative reactive species and in protein misfolding and aggregation in both AD and Parkinson's disease (PD). Although Cu(II) chelation showed higher efficiency for the positional isomers of series 5 than those of series 4 of the hybrids, the Aß-aggregation inhibition appears more dependent on their capacity for fibril intercalation than on copper chelation. Since monoamine oxidases (MAOs) are also important targets for the treatment of AD and PD, the capacity of these hybrids to inhibit MAO-A and MAO-B was evaluated, and they showed higher activity and selectivity for MAO-A. The rationalization of the experimental evaluations (metal chelation and MAO inhibition) was supported by computational molecular modeling studies. Finally, some compounds showed also neuroprotective effects in human neuroblastoma (SH-SY5Y cells) upon treatment with 1-methyl-4-phenylpyridinium (MPP+), a neurotoxic metabolite of a Parkinsonian-inducing agent.

In silico and in vitro studies confirm Ondansetron as a novel acetylcholinesterase and butyrylcholinesterase inhibitor.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is growing rapidly among the elderly population around the world. Studies show that a lack of acetylcholine and butyrylcholine due to the overexpression of enzymes Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) may lead to reduced communication between neuron cells. As a result, seeking novel inhibitors targeting these enzymes might be vital for the future treatment of AD. Ondansetron is used to prevent nausea and vomiting caused by chemotherapy or radiation treatments and is herein shown to be a potent inhibitor of cholinesterase. Comparison is made between Ondansetron and FDA-approved cholinesterase inhibitors Rivastigmine and Tacrine. Molecular docking demonstrates that interactions between the studied ligand and aromatic residues in the peripheral region of the active site are important in binding. Molecular dynamics simulations and binding pose metadynamics show that Ondansetron is highly potent against both enzymes and far better than Rivastigmine. Inhibitor activities evaluated by in vitro studies confirm that the drug inhibits AChE and BChE by non-competitive and mixed inhibition, respectively, with IC50 values 33 µM (AChE) and 2.5 µM (BChE). Based on the findings, we propose that Ondansetron may have therapeutic applications in inhibiting cholinesterase, especially for BChE.

Leflunomide abrogates neuroinflammatory changes in a rat model of Alzheimer's disease: the role of TNF-α/NF-κB/IL-1ß axis inhibition.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases and is associated with disrupted cognition and behavior. Neuroinflammatory pathogenesis is the main component that contributes to AD initiation and progression through microglial activation and neuronal damage. Thus, targeting inflammatory pathways may help manage AD. In this study, for the first time, the potential prophylactic and therapeutic effects of leflunomide were investigated either alone or in combination with rivastigmine in aluminum chloride (AlCl3)-induced AD-like rats using behavioral, biochemical, and histological approaches. Thirty-six adult male albino rats were divided into two protocols: the treatment protocol, subdivided into five groups (n = 6)-(1) control group, (2) AlCl3 (50, 70, 100 mg/kg/I.P) group, (3) reference group (rivastigmine 2 mg/kg/P.O.), (4) experimental group (leflunomide 10 mg/kg/P.O.), and (5) combination group (rivastigmine + leflunomide); and the prophylactic protocol (leflunomide 10 mg/kg/P.O.), which started 2 weeks before AlCl3 induction. The results showed that AlCl3 disrupted learning and memory parameters in rats and increased amyloid-ß plaque deposition and neurofibrillary tangle aggregation. Moreover, AlCl3 administration markedly elevated acetylcholinesterase activity, nuclear factor-kappa ß, tumor necrosis factor-α, and interleukin-1 beta, and marked degenerative changes in the pyramidal neurons. However, administration of leflunomide alone or with rivastigmine in AlCl3-induced AD rats restored most of the behavioral, biochemical, and histological parameters triggered by AlCl3 in rats. Our findings suggest that leflunomide can potentially restore most of the neuronal damage in the hippocampal tissues of AlCl3-induced AD rats. However, these preclinical findings still need to be confirmed in clinical trials.

Rivastigmine ameliorates indomethacin experimentally induced gastric mucosal injury via activating α7nAChR with inhibiting oxidative stress and apoptosis.

The current study aimed to investigate the potential ameliorative role of Rivastigmine (RIVA), the anti-Alzheimer drug, against the gastric mucosal injury caused by indomethacin (IND). The rats were divided into four groups: group I was given a vehicle as a control, group II was given RIVA (0.3 mg/kg) once daily intraperitoneal (ip) for 2 weeks, group III was given a single IP dose of 30 mg/kg IND, and group IV was given RIVA ip 2 weeks before the administration of IND. The gastric mucosal injury was detected by the estimation of ulcer index, gastric acidity, pepsin, and mucin concentrations. Malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), total nitrite/nitrate (NOx), and the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nuclear factor kappa B (NF-κB), Hemoxygenase 1 (HO-1), and caspase-3 were all measured in gastric tissue. In addition, histological assessment and proliferating cell nuclear antigen (PCNA) immuno-expression were studied. Gastric mucosal injury induced by IND was indicated by both biochemical and histopathological assessments. RIVA Pretreatment reduced ulcer index, MDA, TNF-α, IL-6, NF-κB, and caspase-3 and increased SOD, GSH, NOx, and HO-1. RIVA improved the suppressed nuclear immunoreaction for PCNA observed with IND. The current findings provide novel evidence that RIVA possesses a prophylactic action against IND-induced gastric mucosal damage in rats. Despite being a cholinergic drug that is associated with increased pepsin and stomach acidity, RIVA protected against IND-induced gastric mucosal injury via activating α7nAChR and inhibiting oxidative stress and apoptosis.

Rivastigmine attenuates the Alzheimer's disease related protein degradation and apoptotic neuronal death signalling.

Rivastigmine is a clinical drug for patients of Alzheimer's disease (AD) exerting its inhibitory effect on acetylcholinesterase activity however, its effect on other disease-related pathological mechanisms are not yet known. This study was conducted to evaluate the effect of rivastigmine on protein aggregation and degradation related mechanisms employing streptozotocin (STZ) induced experimental rat model. The known inhibitory effect of rivastigmine on cognition and acetylcholinesterase activity was observed in both cortex and hippocampus and further its effect on tau level, amyloid aggregation, biochemical alterations, endoplasmic reticulum (ER) stress, calcium homeostasis, proteasome activity and apoptosis was estimated. STZ administration in rat brain caused significant cognitive impairment, augmented acetylcholinesterase activity, tau phosphorylation and amyloid aggregation which were significantly inhibited with rivastigmine treatment. STZ also caused significant biochemical alterations which were attenuated with rivastigmine treatment. Since AD pathology is related to protein aggregation and we have found disease-related amyloid aggregation, further the investigation was done to decipher the ER functionality and apoptotic signalling. STZ caused significantly altered level of ER stress related markers (GRP78, GADD153 and caspase-12) which were significantly inhibited with rivastigmine treatment. Furthermore, the effect of rivastigmine was estimated on proteasome activity in both regions. Rivastigmine treatment significantly enhances the proteasome activity and may contributes in removal of amyloid aggregation. In conclusion, findings suggested that along with inhibitory effect of rivastigmine on acetylcholinesterase activity and up to some extent on cognition, it has significant effect on disease-related biochemical alterations, ER functionality, protein degradation machinery and neuronal apoptosis.

Hypoxic-conditioned medium from adipose tissue mesenchymal stem cells improved neuroinflammation through alternation of toll like receptor (TLR) 2 and TLR4 expression in model of Alzheimer's disease rats.

Microglia have a pivotal role to initiate immune responses in AD brains through toll-like receptors and induce neuroinflammation. Adipose tissue mesenchymal stem cells (ATSCs) secret many neurotrophic and anti-inflammatory factors called conditioned medium (CM). Many studies have demonstrated that CM of mesenchymal stem cells facilitate regeneration and attenuates inflammation in many disorders. To this purpose, the effect of ATSCs-conditioned medium (ATSC-CM) on brain inflammation and the role of toll-like receptors were investigated in this study. Seventy-two rats were randomly divided into 6 groups: control, sham, sham+ATSC-CM: 200µl ATSC-CM once a day intraperitoneally for 8 days, AD group injected the Aß1-40 intra-hippocampal, AD+ASC-CM, which was injected Aß1-40 intra-hippocampal and 200µl ATSC-CM once a day intraperitoneally for 8 days and AD+ rivastigmine: was injected Aß1-40 intra-hippocampal and received rivastigmine (0.6 mg/kg) orally once a day for 2 weeks. Memory and learning were measured by Morris water maze and novel object recognition tests. For detection of beta-amyloid plaque, Congo red staining was used, and neuronal survival was assessed by Nissl staining. Expression of TLR2 and TLR4 was measured by real-time PCR, and finally, to assess inflammation markers (IL-1ß and TNF-α) in the hippocampus, ELISA kits were used. In treatment group spatial and recognition memory significantly was improved. ATSC-CM administration decreased beta amyloid plaques and enhanced neuronal survival in AD brain rats. In addition, TLR2 and TLR4 expression decreased in treatment group. Results also showed that ATSC-CM reduced IL-1ß and TNF-α as inflammation markers. ATSC-CM improved memory deficit, decreased beta amyloids formation, increased neuron survival, and attenuated inflammation by reducing the expression of TLRs.

Influence of Acetylcholinesterase Inhibitors Used in Alzheimer's Disease Treatment on the Activity of Antioxidant Enzymes and the Concentration of Glutathione in THP-1 Macrophages under Fluoride-Induced Oxidative Stress.

It has been reported that donepezil and rivastigmine, the acetylcholinesterase (AchE) inhibitors commonly used in the treatment of Alzheimer's disease (AD), do not only inhibit AChE but also have antioxidant properties. As oxidative stress is involved in AD pathogenesis, in our study we attempted to examine the influence of donepezil and rivastigmine on the activity of antioxidant enzymes and glutathione concentration in macrophages-an important source of reactive oxygen species and crucial for oxidative stress progression. The macrophages were exposed to sodium fluoride induced oxidative stress. The antioxidant enzymes activity and concentration of glutathione were measured spectrophotometrically. The generation of reactive oxygen species was visualized by confocal microscopy. The results of our study showed that donepezil and rivastigmine had a stimulating effect on catalase activity. However, when exposed to fluoride-induced oxidative stress, the drugs reduced the activity of some antioxidant enzymes (Cat, SOD, GR). These observations suggest that the fluoride-induced oxidative stress may suppress the antioxidant action of AChE inhibitors. Our results may have significance in the clinical practice of treatment of AD and other dementia diseases.

Cholinesterase inhibitor rivastigmine enhances nerve growth factor-induced neurite outgrowth in PC12 cells via sigma-1 and sigma-2 receptors.

Rivastigmine (Riv) is a potent and selective cholinesterase (acetylcholinesterase, AChE and butyrylcholinesterase, BuChE) inhibitor developed for the treatment of Alzheimer's disease (AD). To elucidate whether Riv causes neuronal differentiation, we examined its effect on nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. At concentrations of 0-100 µM, Riv was non-toxic in PC12 cells. Riv caused dose-dependent (10-100 µM) enhancement of NGF-induced neurite outgrowth, which was completely inhibited by the TrkA antagonist GW-441756. By contrast, Riv-mediated enhancement of neurite outgrowth was not blocked by the acetylcholine receptor antagonists, scopolamine and hexamethonium. However, the sigma-1 receptor (Sig-1R) antagonist NE-100 and sigma-2 receptor (Sig-2R) antagonist SM-21 each blocked about half of the Riv-mediated enhancement of NGF-induced neurite outgrowth. Interestingly, the simultaneous application of NE-100 and SM-21 completely blocked the enhancement of NGF-induced neurite outgrowth by Riv. These findings suggest that both Sig-1R and Sig-2R play important roles in NGF-induced neurite outgrowth through TrkA and that Riv may contribute to neuronal repair via Sig-1R and Sig-2R in AD therapy.

Paroxetine and rivastigmine mitigates adjuvant-induced rheumatoid arthritis in rats: Impact on oxidative stress, apoptosis and RANKL/OPG signals.

Rheumatoid arthritis (RA) is considered a form of inflammatory autoimmune disease with unknown etiology, but environmental and genetic causes are sharing. T-cells, B-cells, synovial cells, osteoclast, and chondrocytes are the main cell types in RA pathophysiology. The present study aimed to investigate the anti-rheumatic effects of paroxetine, a selective serotonin reuptake inhibitor (SSRI), and rivastigmine, acetyl choline esterase inhibitor (AChEI), in complete Freund's adjuvant (CFA)-induced RA. Adult female rats were categorized into five groups of eight rats each: normal control received vehicles only, RA control received CFA (0.4 ml, s.c) dexamethasone group (1 mg/kg/day, p.o), paroxetine group (10 mg/kg/day, i.p) and rivastigmine group (1 mg/kg/day, i.p). All treatments were administered for 13 consecutive days. Specific rheumatoid marker rheumatoid factor (RF), cartilage oligomeric protein (COMP) and matrix metalloproteinase-3 (MMP-3) were determined. Serum MDA and reduced GSH levels were investigated as oxidative stress biomarkers. IL-6, TNF-α, and monocyte chemotactic protein-1 (MCP-1) were also determined as inflammatory biomarkers. Tissue Receptor activator of nuclear factor kappa-B ligand/osteoprotegerin (RANKL/OPG) expression levels were detected using qRT-PCR. Paroxetine and rivastigmine significantly reduced RF, COMP, MMP-3, IL-6, TNF-α, and MCP-1 serum levels. Tested drugs also significantly reduced serum MDA and increased GSH levels. In addition, paroxetine and rivastigmine attenuated histopathological variations by reducing pannus formation and return synovial fluid near to normal. Administration of paroxetine or rivastigmine normalized caspase-3 and RANKL/OPG in CFA-induced RA. In conclusion, paroxetine and rivastigmine possess antirheumatoid effects in CFA-induced RA which is mediated through antioxidant, anti-inflammatory, antiapoptotic and modulation of RANKL/OPG expression levels.

Effect of acetylcholinesterase inhibitors donepezil and rivastigmine on the activity and expression of cyclooxygenases in a model of the inflammatory action of fluoride on macrophages obtained from THP-1 monocytes.

Inflammation is an important factor in the development of many diseases of the central nervous system, including Alzheimer's disease and other types of dementia. ‪Given that acetylcholinesterase inhibitors are also currently believed to have anti-inflammatory properties, the purpose of this study was to investigate the effect of acetylcholinesterase inhibitors (rivastigmine, donepezil) on cyclooxygenase activity and expression using the proinflammatory action of fluoride (F-) on cultured macrophages obtained from THP-1 monocytes. COX-1 and COX-2 activity was determined through measurement of the products of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in cell culture supernatants. Expression of COX-1 and COX-2 proteins was examined immunocytochemically, and mRNA expression was determined by qRT PCR. ‪‪ Our study confirmed the inhibitory effects of donepezil and rivastigmine on the production of PGE2, TXB2, COX-1 and COX-2 mRNA and protein expression in macrophages. We also demonstrated that the pro-inflammatory effect of fluoride may be reduced by the use of both drugs. The additive effect of these drugs cannot be ruled out, and effects other than those observed in the use of one drug should also be taken into account.

Evaluation of the rivastigmine role against botulinum toxin-A-induced osteoporosis in albino rats: A biochemical, histological, and immunohistochemical study.

The present study aimed to evaluate the role of rivastigmine against the effect of a single unilateral botulinum toxin-A (BTX-A) injection on the bone and bone marrow of adult albino rats 4 weeks after injection. Twenty-four Wistar albino rats were divided into four equal groups: group I, which received distilled water; group II, which received rivastigmine (0.3 mg/kg daily, intraperitoneally for 4 weeks); group III, which received BTX-A (4 IU in 0.2 mL physiological saline) single dose, intramuscularly; and group IV, which received BTX-A + rivastigmine. The results revealed that BTX-A induced a significant decrease in the calcium level with a significant increase in the phosphorus, alkaline phosphatase, C-reactive protein, and tumor necrosis factor α levels in serum. Furthermore, a significant increase in malondialdehyde with a significant decrease in reduced glutathione activities in both bone and bone marrow. Histologically, a distortion and thinning out of the compact bone and trabeculae of cancellous bone of the rat femur in the BTX-A group with an increase in adipocytes in adjacent bone marrow were detected. Immunohistochemically, Cluster of Differentiation 68 (CD68) showed a significant increase in both osteoclasts and bone marrow macrophage. Rivastigmine treatment could relieve the toxic effects induced by BTX-A. In conclusion, rivastigmine has a protective effect against the hazardous effects of BTX-A on bone and bone marrow.

Nature-based molecules combined with rivastigmine: A symbiotic approach for the synthesis of new agents against Alzheimer's disease.

Starting from nature as original source, new potential agents with pleiotropic activities have been synthesized and evaluated as neuroprotective agents. In this work, novel nature-based hybrids, combining antioxidant motifs with rivastigmine, have been designed and synthesized. The biological results revealed that the new compounds inhibit both AChE and BuChE. In particular, lipoic acid hybrids LA1, LA2, LA3 resulted to be the most potent inhibitors of BuChE showing IC50 values ranging from 340 to 378 nM. Analogously, all the compounds were able to inhibit the self ß-amyloid1-42 aggregation. The gallic acid hybrid GA2 as well as the 2-chromonecarboxylic acid hybrids CA1 and CA2 prevented the self-mediated Aß aggregation with percentages of inhibition ranging from 53% to 59%. Finally, some of them also show potent neuroprotective effects against glutamate-induced cell death and low toxicity in HT22 cells.

Discovery of Novel Pyrazolopyrimidinone Derivatives as Phosphodiesterase 9A Inhibitors Capable of Inhibiting Butyrylcholinesterase for Treatment of Alzheimer's Disease.

Discovery of multitarget-directed ligands (MTDLs), targeting different factors simultaneously to control the complicated pathogenesis of Alzheimer's disease (AD), has become an important research area in recent years. Both phosphodiesterase 9A (PDE9A) and butyrylcholinesterase (BuChE) inhibitors could participate in different processes of AD to attenuate neuronal injuries and improve cognitive impairments. However, research on MTDLs combining the inhibition of PDE9A and BuChE simultaneously has not been reported yet. In this study, a series of novel pyrazolopyrimidinone-rivastigmine hybrids were designed, synthesized, and evaluated in vitro. Most compounds exhibited remarkable inhibitory activities against both PDE9A and BuChE. Compounds 6c and 6f showed the best IC50 values against PDE9A (6c, 14 nM; 6f, 17 nM) together with the considerable inhibition against BuChE (IC50, 6c, 3.3 µM; 6f, 0.97 µM). Their inhibitory potencies against BuChE were even higher than the anti-AD drug rivastigmine. It is worthy mentioning that both showed moderate selectivity for BuChE over acetylcholinesterase (AChE). Molecular docking studies revealed their binding patterns and explained the influence of configuration and substitutions on the inhibition of PDE9A and BuChE. Furthermore, compounds 6c and 6f exhibited negligible toxicity, which made them suitable for the further study of AD in vivo.

Cholinergic Anti-Inflammatory Pathway Does Not Contribute to Prevention of Ulcerative Colitis by Novel Indoline Carbamates.

Indoline carbamates, AN680 and AN917 decrease cytokines, TNF-α and IL-6 in peritoneal macrophages activated by lipopolysaccharide (LPS) and in mouse tissues after LPS injection. They prevent nuclear translocation of nuclear factor κB (NF-κB) and activator protein 1. Only AN917 inhibits cholinesterase (ChE) at relevant concentrations. ChE inhibitors decrease NF-κB by activating α7 nicotinic acetylcholine receptors (α7nAChR). The current study compared the effect of rivastigmine, a ChE inhibitor, AN680 and AN917 on ulcerative colitis induced in mice by ingestion of dextran sodium sulfate (4.5%) solution. Rivastigmine (1 mg/kg), AN680 (2.5-10 mg/kg) and AN917 (2-5 mg/kg) were injected subcutaneously once daily for 8 days. Disease severity was assessed by disease activity index (DAI), colonoscopy, colon length and body weight loss, colonic levels of TNF-α, IL-6, IL-1ß and myeloid peroxidase (MPO) activity. AN680 (5 mg/kg) reduced DAI, colon shrinkage, weight loss, histopathological signs of colon damage, MPO activity, TNF-α, IL-1ß and IL-6 levels without inhibiting ChE. AN917 (5 mg/kg) and rivastigmine (1 mg/kg) inhibited ChE in plasma and colon by 65%, reduced DAI, MPO activity and IL-6, but not TNF-α or IL-1ß. AN917 did not prevent weight loss or colon shrinkage. Mecamylamine abolished the reduction of DAI, MPO activity and IL-6 by AN917 and rivastigmine, indicating they were mediated by α7nAChR. CONCLUSIONS: AN680 is very effective in preventing DSS-induced UC in mice and may therefore have potential therapeutic application in humans. Addition of ChE inhibition and indirect activation of α7nAChR lessens the efficacy of AN917 in this model.

Design, synthesis, biological evaluation, and molecular modeling studies of chalcone-rivastigmine hybrids as cholinesterase inhibitors.

A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC50 to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer's disease (AD) treatment.

DL0410, a novel dual cholinesterase inhibitor, protects mouse brains against Aß-induced neuronal damage via the Akt/JNK signaling pathway.

AIM: 1,1'-([1,1'-Biphenyl]-4,4'-diyl)bis(3-(piperidin-1-yl)propan-1-one)dihydrochloride (DL0410) is a novel synthetic dual acetylcholinesterase (AChE)/butyrocholinesterase (BuChE) inhibitor, which has shown a potential therapeutic effect on Alzheimer's disease (AD). In this study we examined whether DL0410 produced neuroprotective effects in an AD cellular model and an Aß1-42-induced amnesia mouse model. METHODS: The in vitro inhibitory activities against AChE and BuChE were estimated using Ellman's assay. Copper-induced toxicity in APPsw-SY5Y cells was used as AD cellular model, the cell viability was assessed using MTS assay, and cell apoptosis was evaluated based on mitochondrial membrane potential detection. Aß1-42-induced amnesia mouse model was made in male mice by injecting aggregated Aß1-42 (2 µg in 2 µL 0.1% DMSO) into the right cerebral ventricle. Before and after Aß1-42 injection, the mice were orally administered DL0410 (1, 3, 9 mg·kg-1·d-1) or rivastigmine (2 mg·kg-1·d-1) for 3 and 11 d, respectively. Memory impairments were examined using Morris water maze (MWM) test and passive avoidance test. The expression levels of APP, CREB, BDNF, JNK and Akt in the mouse brains were measured with either immunohistochemistry or Western blotting. RESULTS: DL0410 exhibited in vitro inhibitory abilities against AChE and BuChE with IC50 values of 0.286±0.004 and 3.962±0.099 µmol/L, respectively, which were comparable to those of donepezil and rivastigmine. In APPsw-SY5Y cells, pretreatment with DL0410 (1, 3, and 10 µmol/L) decreased the phosphorylation of JNK and increased the phosphorylation of Akt, markedly decreased copper-stimulated Aß1-42 production, reversed the loss of mitochondrial membrane potential, and dose-dependently increased the cell viability. In Aß1-42-treated mice, DL0410 administration significantly ameliorated learning and memory deficits in MWM test and passive avoidance test. Furthermore, DL0410 administration markedly decreased Aß1-40/42 deposits in mouse cerebral cortices, and significantly up-regulated neurotrophic CREB/BDNF. Meanwhile, Akt/JNK signaling pathway may play a key role in the neuroprotective effect of DL0410. CONCLUSION: DL0410 ameliorates cognitive deficit and exerts neuronal protection in AD models, implicating this compound as a candidate drug for the prevention and therapy of AD.

Multitarget strategies in Alzheimer's disease: benefits and challenges on the road to therapeutics.

Alzheimer's disease is a multifactorial syndrome, for which effective cures are urgently needed. Seeking for enhanced therapeutic efficacy, multitarget drugs have been increasingly sought after over the last decades. They offer the attractive prospect of tackling intricate network effects, but with the benefits of a single-molecule therapy. Herein, we highlight relevant progress in the field, focusing on acetylcholinesterase inhibition and amyloid pathways as two pivotal features in multitarget design strategies. We also discuss the intertwined relationship between selected molecular targets and give a brief glimpse into the power of multitarget agents as pharmacological probes of Alzheimer's disease molecular mechanisms.