Higher levels of AKT-interacting protein in the frontal pole from people with schizophrenia are limited to a sub-group who have a marked deficit in cortical muscarinic M1 receptors.

We are studying the molecular pathology of a sub-group within schizophrenia (∼ 25 %: termed Muscarinic Receptor Deficit subgroup of Schizophrenia (MRDS)) who can be separated because they have very low levels of cortical muscarinic M1 receptors (CHRM1). Based on our transcriptomic data from Brodmann's area ((BA) 9, 10 and 33 (controls, schizophrenia and mood disorders) and the cortex of the CHRM1-/- mouse (a molecular model of aberrant CHRM1 signaling), we predicted levels of AKT interacting protein (AKTIP), but not tubulin alpha 1b (TUBA1B) or AKT serine/threonine kinase 1 (AKT1) and pyruvate dehydrogenase kinase 1 (PDK1) (two AKTIP-functionally associated proteins), would be changed in MRDS. Hence, we used Western blotting to measure AKTIP (BA 10: controls, schizophrenia and mood disorders; BA 9: controls and schizophrenia) plus TUBA1B, AKT1 and PDK1 (BA 10: controls and schizophrenia) proteins. The only significant change with diagnosis was higher levels of AKTIP protein in BA 10 (Cohen's d = 0.73; p = 0.02) in schizophrenia compared to controls due to higher levels of AKTIP only in people with MRDS (Cohen's d = 0.80; p = 0.03). As AKTIP is involved in AKT1 signaling, our data suggests that signaling pathway is particularly disturbed in BA 10 in MRDS.

Activation of M4 muscarinic receptors in the striatum reduces tic-like behaviours in two distinct murine models of Tourette syndrome.

BACKGROUND AND PURPOSE: Current pharmacotherapies for Tourette syndrome (TS) are often unsatisfactory and poorly tolerated, underscoring the need for novel treatments. Insufficient striatal acetylcholine has been suggested to contribute to tic ontogeny. Thus, we tested whether activating M1 and/or M4 receptors-the two most abundant muscarinic receptors in the striatum-reduced tic-related behaviours in mouse models of TS. EXPERIMENTAL APPROACH: Studies were conducted using CIN-d and D1CT-7 mice, two TS models characterized by early-life depletion of striatal cholinergic interneurons and cortical neuropotentiation, respectively. First, we tested the effects of systemic and intrastriatal xanomeline, a selective M1/M4 receptor agonist, on tic-like and other TS-related responses. Then, we examined whether xanomeline effects were reduced by either M1 or M4 antagonists or mimicked by the M1/M3 agonist cevimeline or the M4 positive allosteric modulator (PAM) VU0467154. Finally, we measured striatal levels of M1 and M4 receptors and assessed the impact of VU0461754 on the striatal expression of the neural marker activity c-Fos. KEY RESULTS: Systemic and intrastriatal xanomeline reduced TS-related behaviours in CIN-d and D1CT-7 mice. Most effects were blocked by M4, but not M1, receptor antagonists. VU0467154, but not cevimeline, elicited xanomeline-like ameliorative effects in both models. M4, but not M1, receptors were down-regulated in the striatum of CIN-d mice. Additionally, VU0467154 reduced striatal c-Fos levels in these animals. CONCLUSION AND IMPLICATIONS: Activation of striatal M4, but not M1, receptors reduced tic-like manifestations in mouse models, pointing to xanomeline and M4 PAMs as novel putative therapeutic strategies for TS.

A comprehensive assessment of the cholinergic-supporting and cognitive-enhancing effects of Rosa damascena Mill. (Damask rose) essential oil on scopolamine-induced amnestic rats.

INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative condition characterized by gradual loss of cognitive abilities (dementia) and is a major public health problem. Here, we aimed at investigating the effects of Rosa damascena essential oil (RDEO) on learning and memory functions in a rat model of amnesia induced by scopolamine, as well as on changes in acetylcholinesterase (AChE) activity, M1 muscarinic acetylcholine receptor (mAChR) expression, and brain-derived neurotrophic factor (BDNF) levels in the extracted brain tissues. METHODS: The control, amnesia (scopolamine, 1 mg/kg/i.p.) and treatment (RDEO, 100 µL/kg/p.o. or galantamine, 1.5 mg/kg/i.p.) groups were subjected to Morris water maze and new object recognition tests. AChE activity was assayed by ELISA, and M1 mAChR and BDNF concentration changes were determined by western blotting. Also, using computational tools, human M1 mAChR was modeled in an active conformation, and the major components of RDEO were docked onto this receptor. RESULTS: According to our behavioral tests, RDEO was able to mitigate the learning and memory impairments caused by scopolamine in vivo. Our in vitro assays showed that the observed positive effects correlated well with a decrease in AChE activity and an increase in M1 mAChR and BDNF levels in amnestic rat brains. We also demonstrated in an in silico setting that the major components of RDEO, specifically -citronellol, geraniol, and nerol, could be accommodated favorably within the allosteric binding pocket of active-state human M1 mAChR and anchored here chiefly by hydrogen-bonding and alkyl-π interactions. CONCLUSION: Our findings offer a solid experimental foundation for future RDEO-based medicinal product development for patients suffering from AD.

Cholinergic signaling via muscarinic M1 receptor confers resistance to docetaxel in prostate cancer.

Docetaxel is the most commonly used chemotherapy for advanced prostate cancer (PC), including castration-resistant disease (CRPC), but the eventual development of docetaxel resistance constitutes a major clinical challenge. Here, we demonstrate activation of the cholinergic muscarinic M1 receptor (CHRM1) in CRPC cells upon acquiring resistance to docetaxel, which is manifested in tumor tissues from PC patients post- vs. pre-docetaxel. Genetic and pharmacological inactivation of CHRM1 restores the efficacy of docetaxel in resistant cells. Mechanistically, CHRM1, via its first and third extracellular loops, interacts with the SEMA domain of cMET and forms a heteroreceptor complex with cMET, stimulating a downstream mitogen-activated protein polykinase program to confer docetaxel resistance. Dicyclomine, a clinically available CHRM1-selective antagonist, reverts resistance and restricts the growth of multiple docetaxel-resistant CRPC cell lines and patient-derived xenografts. Our study reveals a CHRM1-dictated mechanism for docetaxel resistance and identifies a CHRM1-targeted combinatorial strategy for overcoming docetaxel resistance in PC.

Bioinformatic Analysis on the Prognostic Value of Neurotransmitter Receptor-Related Genes in Kidney Renal Clear Cell Carcinoma.

Context: Kidney renal clear-cell carcinoma (KIRC) is a malignant tumor. At an early stage, KIRC patients may experience only mild fever and fatigue or even no symptoms, and these early nonspecific indications can delay treatment. Neurotransmitters and their receptors may be very useful in determining tumorigenesis and predicting metastasis. Objective: The study intended to investigate the predictive value of neurotransmitter receptor-related genes (NRRGs) using public KIRC data, by determining the biological processes that implicate the prognostic NRRGs and establishing a predictive NR-related risk model, to provide an empirical basis for identifying and treating KIRC patients. Design: The research team performed a genetic case-control study. Setting: The study took place at Research Center of Health, Big Data Mining and Applications, Wannan Medical College, Wuhu, China. Methods: The research team: (1) obtained the transcriptome data related to KIRC from the Cancer Genome Atlas (TCGA) and ArrayExpress databases; (2) developed the differentially expressed NRRGs (DENRRGs) by identifying the NRRGs that intersected with DEGs in KIRC and normal samples; (3) carried out functional enrichment analyses of the DENRRGs; (4) screened the characteristic genes of the DENRRGs using machine learning; (5) created a predictive model using multivariate Cox analyses of the distinctive genes; (6) obtained independent prognostic factors for KIRC patients and established a nomograph model; (7) investigated the sensitivity of KIRC patients to therapeutic agents to examine the variations in immunological features between high-risk and low-risk individuals. Results: Differential analysis found that 115 NRRGs intersected with 5275 DEGs to provide 52 DENRRGs. Functional enrichment showed that DENRRGs were mainly involved in signal transduction in the nervous system. The machine learning on the 52 DENRRGs filtered out nine characteristic genes. Subsequently, the research team found eight prognostic biomarkers-histamine receptor H2 (HRH2), gamma-aminobutyric acid (GABA) receptor subunit epsilon (GABRE), cholinergic receptor nicotinic delta subunit (CHRND), glutamate receptor ionotropic subunit 2D (GRIN2D), glutamate metabotropic receptor 4 (GRM4), glycine receptor alpha 3 (GLRA3), cholinergic receptor nicotinic beta 4 subunit (CHRNB4), and cholinergic receptor muscarinic-1 (CHRM1)-and established a predictive model. Furthermore, the team precisely predicted the KIRC patients' prognoses using a nomogram that combined their ages, risk scores, and M stages. The infiltration levels of 21 immune cells also significantly differed between the high-risk and low-risk groups, with neutrophils having a significant positive correlation with GABRE and HRH2 and a significant negative correlation with CHRNB4 and GRM4. Finally, the 50% inhibitory concentration (IC50) values for various drugs, such as 5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside (AICAR), 8-hydroxy-7-(6-sulfonaphthalen-2-yl)diazenyl-quinoline-5-sulfonic acid (NSC-87877), Sunitinib, c-Jun N-terminal kinase (JNK) inhibitor VIII, and tanespimyci (X17.AAG) were significantly lower for high-risk group. Conclusions: By studying the relevance of biomarkers to the immunological microenvironment of KIRC, the current research team was able to propose a new predictive model for KIRC based on NRRGs, to offer a novel viewpoint for investigating KIRC. The study's results suggest new avenues for research into the pathophysiology and therapy of KIRC. Determining the precise molecular processes by which predictive biomarkers regulate KIRC requires further evidence and analysis.

Sex, Age, and Regional Differences in CHRM1 and CHRM3 Genes Expression Levels in the Human Brain Biopsies: Potential Targets for Alzheimer's Disease-related Sleep Disturbances.

BACKGROUND: Cholinergic hypofunction and sleep disturbance are hallmarks of Alzheimer's disease (AD), a progressive disorder leading to neuronal deterioration. Muscarinic acetylcholine receptors (M1-5 or mAChRs), expressed in hippocampus and cerebral cortex, play a pivotal role in the aberrant alterations of cognitive processing, memory, and learning, observed in AD. Recent evidence shows that two mAChRs, M1 and M3, encoded by CHRM1 and CHRM3 genes, respectively, are involved in sleep functions and, peculiarly, in rapid eye movement (REM) sleep. METHODS: We used twenty microarray datasets extrapolated from post-mortem brain tissue of nondemented healthy controls (NDHC) and AD patients to examine the expression profile of CHRM1 and CHRM3 genes. Samples were from eight brain regions and stratified according to age and sex. RESULTS: CHRM1 and CHRM3 expression levels were significantly reduced in AD compared with ageand sex-matched NDHC brains. A negative correlation with age emerged for both CHRM1 and CHRM3 in NDHC but not in AD brains. Notably, a marked positive correlation was also revealed between the neurogranin (NRGN) and both CHRM1 and CHRM3 genes. These associations were modulated by sex. Accordingly, in the temporal and occipital regions of NDHC subjects, males expressed higher levels of CHRM1 and CHRM3, respectively, than females. In AD patients, males expressed higher levels of CHRM1 and CHRM3 in the temporal and frontal regions, respectively, than females. CONCLUSION: Thus, substantial differences, all strictly linked to the brain region analyzed, age, and sex, exist in CHRM1 and CHRM3 brain levels both in NDHC subjects and in AD patients.

Integrated bioinformatics analysis and screening of hub genes in polycystic ovary syndrome.

PURPOSE: Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders, posing a serious threat to the health of women. Herein, we aimed to explore new biomarkers and potential therapeutic targets for PCOS by employing integrated bioinformatics tools. METHODS: Three gene expression profile datasets (GSE138518, GSE155489, GSE106724) were obtained from the Gene Expression Omnibus database and the differentially expressed genes in PCOS and normal groups with an adjusted p-value < 0.05 and a |log fold change (FC) | > 1.2 were first identified using the DESeq package. The weighted correlation network analysis (WGCNA) R package was used to identify clusters of highly correlated genes or modules associated with PCOS. Protein-protein interaction (PPI) network analysis and visualization of genes in the key module were performed using the STRINGdb database and the NetworkX package (edge > 5), respectively. The genes overlapping among the key module genes and PCOS-associated genes were further analyzed. Ligand molecules with strong binding energy < -10 kJ/mol to GNB3 were screened in the drug library using MTiOpenScreen. AutoDock, ChimeraX, and BIOVIA Discovery Studio Visualizer were further used to elucidate the mechanism of ligand interaction with GNB3. Finally, the relationship between GNB3 and PCOS was verified using experimental models in vivo and in vitro. RESULTS: Of the 11 modules identified by WGCNA, the black module had the highest correlation with PCOS (correlation = 0.96, P = 0.00016). The PPI network of 351 related genes revealed that VCL, GNB3, MYH11, LMNA, MLLT4, EZH2, PAK3, and CHRM1 have important roles in PCOS. The hub gene GNB3 was identified by taking the intersection of PCOS-related gene sets. MTiOpenScreen revealed that five compounds interacted with GNB3. Of these five, compound 1 had the strongest binding ability and can bind amino acids in the WD40 motif of GNB3, which in turn affects the function of the G protein-coupled receptor ß subunit. GNB3 was also significantly downregulated in PCOS models. CONCLUSION: We identified the hub gene GNB3 as the most important regulatory gene in PCOS. We suggest that compound 1 can target the WD40 motif of GNB3 to affect related functions and must be considered as a lead compound for drug development. This study will provide new insights into the development of PCOS-related drugs.

Ovariectomy reduces cholinergic modulation of excitatory synaptic transmission in the rat entorhinal cortex.

Estrogens are thought to contribute to cognitive function in part by promoting the function of basal forebrain cholinergic neurons that project to the hippocampus and cortical regions including the entorhinal cortex. Reductions in estrogens may alter cognition by reducing the function of cholinergic inputs to both the hippocampus and entorhinal cortex. In the present study, we assessed the effects of ovariectomy on proteins associated with cholinergic synapses in the entorhinal cortex. Ovariectomy was conducted at PD63, and tissue was obtained on PD84 to 89 to quantify changes in the degradative enzyme acetylcholinesterase, the vesicular acetylcholine transporter, and muscarinic M1 receptor protein. Although the vesicular acetylcholine transporter was unaffected, ovariectomy reduced both acetylcholinesterase and M1 receptor protein, and these reductions were prevented by chronic replacement of 17ß-estradiol following ovariectomy. We also assessed the effects of ovariectomy on the cholinergic modulation of excitatory transmission, by comparing the effects of the acetylcholinesterase inhibitor eserine on evoked excitatory synaptic field potentials in brain slices obtained from intact rats, and from ovariectomized rats with or without 17ß-estradiol replacement. Eserine is known to prolong the effects of endogenously released acetylcholine, resulting in an M1-like mediated reduction of glutamate release at excitatory synapses. The reduction in excitatory synaptic potentials in layer II of the entorhinal cortex induced by 15-min application of 10 µM eserine was greatly reduced in slices from ovariectomized rats as compared to intact rats and ovariectomized rats with replacement of 17ß-estradiol. The reduced modulatory effect of eserine is consistent with the observed changes in cholinergic proteins, and suggests that reductions in 17ß-estradiol following ovariectomy lead to impaired cholinergic function within the entorhinal cortex.

Study on the mechanism of Qiju Dihuang pill in the treatment of ophthalmic diseases based on systems pharmacology.

Qiju Dihuang pill is one of the common Traditional Chinese Medicine to treat ophthalmic diseases. In vivo studies have suggested that Qiju Dihuang pill can be used for treating glaucoma, and it can also be used clinically to treat cataract patients. However, the bioactive ingredients and the therapeutic mechanism of Qiju Dihuang pill on treating these ophthalmic diseases remained unclear. Presently, a systems pharmacology approach which combines pharmacokinetic screening, targeted fishing, biological function enrichment, network pharmacology, and molecular docking analysis, was employed. A total of 134 active ingredients with 72 corresponding targets are identified from Qiju Dihuang pill. Additionally, 3 core targets including CHRM1, ESR1, and AR are obtained from the ingredients and drug targets network analysis. Besides, gen ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis reveal 3 important biological pathways, that is, calcium signaling pathway, insulin signaling pathway and Vascular endothelial growth factor signaling pathway. In final, a molecular docking model was constructed to study the interaction mechanism between active components and drug targets at the molecular level. All the findings show that Qiju Dihuang pill achieves therapeutic effects on treating ophthalmic diseases by regulating the crucial targets of the compounds in it. This work not only provides insight into the therapeutic mechanism of herbal medicine in the treatment of ophthalmic diseases from a multiscale perspective, but also offers an effective approach for drug discovery and development of Traditional Chinese Medicine.

The M1 muscarinic receptor is present in situ as a ligand-regulated mixture of monomers and oligomeric complexes.

The quaternary organization of rhodopsin-like G protein-coupled receptors in native tissues is unknown. To address this we generated mice in which the M1 muscarinic acetylcholine receptor was replaced with a C-terminally monomeric enhanced green fluorescent protein (mEGFP)-linked variant. Fluorescence imaging of brain slices demonstrated appropriate regional distribution, and using both anti-M1 and anti-green fluorescent protein antisera the expressed transgene was detected in both cortex and hippocampus only as the full-length polypeptide. M1-mEGFP was expressed at levels equal to the M1 receptor in wild-type mice and was expressed throughout cell bodies and projections in cultured neurons from these animals. Signaling and behavioral studies demonstrated M1-mEGFP was fully active. Application of fluorescence intensity fluctuation spectrometry to regions of interest within M1-mEGFP-expressing neurons quantified local levels of expression and showed the receptor was present as a mixture of monomers, dimers, and higher-order oligomeric complexes. Treatment with both an agonist and an antagonist ligand promoted monomerization of the M1-mEGFP receptor. The quaternary organization of a class A G protein-coupled receptor in situ was directly quantified in neurons in this study, which answers the much-debated question of the extent and potential ligand-induced regulation of basal quaternary organization of such a receptor in native tissue when present at endogenous expression levels.

Germacrone alleviates okadaic acid-induced neurotoxicity in PC12 cells via M1 muscarinic receptor-mediated Galphaq (Gq)/phospholipase C beta (PLCß)/ protein kinase C (PKC) signaling.

Alzheimer's disease (AD) is a neurodegenerative disorder with prominent individual morbidity and mortality among elderly people. Germacrone (Germ) has been reported to exert dominant protective roles in multiple human diseases, and neurological diseases are also included. The intention of this paper is to determine the impacts of Germ on okadaic acid (OA)-treated PC12 cells and confirm the hidden regulatory mechanism. First, PC12 cells were induced by OA in the absence or presence of Germ. Cell counting kit-8 assay was to monitor cell proliferation. Western blot was to test the protein levels of cholinergic muscarinic M1 receptor (CHRM1), Galphaq (Gq), phospholipase C beta (PLCß) and protein kinase C (PKC). The levels of reactive oxygen species (ROS) and other oxidative stress markers were evaluated using corresponding kits. ELISA was used to estimate the levels of AD markers. RT-qPCR was used to examine the mRNA levels of beta-site amyloid-precursor-protein-cleaving enzyme 1 (BACE-1) and apolipoprotein E (APOE). The results uncovered that Germ enhanced the proliferation of OA-insulted PC12 cells, elevated the protein level of CHRM1 and activated the Gq/PLCß/PKC signaling. Moreover, after OA-induced PC12 cells were administered with Germ, insufficiency of CHRM1 impeded cell proliferation, enhanced oxidative stress and neuron injury and inactivated the Gq/PLCß/PKC signaling. Furthermore, the addition of Gq inhibitor UBO-QIC, PLCß inhibitor U73122 or PKC inhibitor Go6983 reversed the enhanced proliferation, the reduced oxidative stress and neuron injury in OA-treated PC12 cells caused by Germ. Collectively, Germ modulated M1 muscarinic receptor-mediated Gq/PLCß/PKC signaling, thereby alleviating OA-induced PC12 cell injury.

Hypermethylation of PI3K-AKT signalling pathway genes is associated with human neural tube defects.

Neural tube defects (NTDs) are a group of common and severe congenital malformations. The PI3K-AKT signalling pathway plays a crucial role in the neural tube development. There is limited evidence concerning any possible association between aberrant methylation in PI3K-AKT signalling pathway genes and NTDs. Therefore, we aimed to investigate potential associations between aberrant methylation of PI3K-AKT pathway genes and NTDs. Methylation studies of PI3K-AKT pathway genes utilizing microarray genome-methylation data derived from neural tissues of ten NTD cases and eight non-malformed controls were performed. Targeted DNA methylation analysis was subsequently performed in an independent cohort of 73 NTD cases and 32 controls to validate the methylation levels of identified genes. siRNAs were used to pull-down the target genes in human embryonic stem cells (hESCs) to examine the effects of the aberrant expression of target genes on neural cells. As a result, 321 differentially hypermethylated CpG sites in the promoter regions of 30 PI3K-AKT pathway genes were identified in the microarray data. In target methylation analysis, CHRM1, FGF19, and ITGA7 were confirmed to be significantly hypermethylated in NTD cases and were associated with increased risk for NTDs. The down-regulation of FGF19, CHRM1, and ITGA7 impaired the formation of rosette-like cell aggregates. The down-regulation of those three genes affected the expression of PAX6, SOX2 and MAP2, implying their influence on the differentiation of neural cells. This study for the first time reported that hypermethylation of PI3K-AKT pathway genes such as CHRM1, FGF19, and ITGA7 is associated with human NTDs.

Cadmium-induced neurotoxic effects on rat basal forebrain cholinergic system through thyroid hormones disruption.

Cadmium (Cd) single and repeated exposure produces cognitive dysfunctions. Basal forebrain cholinergic neurons (BFCN) regulate cognitive functions. BFCN loss or cholinergic neurotransmission dysfunction leads to cognitive disabilities. Thyroid hormones (THs) maintain BFCN viability and functions, and Cd disrupts their levels. However, Cd-induced BFCN damages and THs disruption involvement was not studied. To research this we treated male Wistar rats intraperitoneally with Cd once (1 mg/kg) or repetitively for 28 days (0.1 mg/kg) with/without triiodothyronine (T3, 40 µg/kg/day). Cd increased thyroid-stimulating-hormone (TSH) and decreased T3 and tetraiodothyronine (T4). Cd altered cholinergic transmission and induced a more pronounced neurodegeneration on BFCN, mediated partially by THs reduction. Additionally, Cd antagonized muscarinic 1 receptor (M1R), overexpressed acetylcholinesterase S variant (AChE-S), downregulated AChE-R, M2R, M3R and M4R, and reduced AChE and choline acetyltransferase activities through THs disruption. These results may assist to discover cadmium mechanisms that induce cognitive disabilities, revealing a new possible therapeutic tool.

Long-term effects of early postnatal nicotine exposure on cholinergic function in the mouse hippocampal CA1 region.

In rodent models of smoking during pregnancy, early postnatal nicotine exposure results in impaired hippocampus-dependent memory, but the underlying mechanism remains elusive. Given that hippocampal cholinergic systems modulate memory and rapid development of hippocampal cholinergic systems occurs during nicotine exposure, here we investigated its impacts on cholinergic function. Both nicotinic and muscarinic activation produce transient or long-lasting depression of excitatory synaptic transmission in the hippocampal CA1 region. We found that postnatal nicotine exposure impairs both the induction and nicotinic modulation of NMDAR-dependent long-term depression (LTD). Activation of muscarinic receptors decreases excitatory synaptic transmission and CA1 network activity in both wild-type and α2 knockout mice. These muscarinic effects are still observed in nicotine-exposed mice. M1 muscarinic receptor activity is required for mGluR-dependent LTD. Early postnatal nicotine exposure has no effect on mGluR-dependent LTD induction, suggesting that it has no effect on the function of m1 muscarinic receptors involved in this form of LTD. Our results demonstrate that early postnatal nicotine exposure has more pronounced effects on nicotinic function than muscarinic function in the hippocampal CA1 region. Thus, impaired hippocampus-dependent memory may arise from the developmental disruption of nicotinic cholinergic systems in the hippocampal CA1 region.

Reduction of falls in a rat model of PD falls by the M1 PAM TAK-071.

RATIONALE: In addition to the disease-defining motor symptoms, patients with Parkinson's disease (PD) exhibit gait dysfunction, postural instability, and a propensity for falls. These dopamine (DA) replacement-resistant symptoms in part have been attributed to loss of basal forebrain (BF) cholinergic neurons and, in interaction with striatal dopamine (DA) loss, to the resulting disruption of the attentional control of balance and complex movements. Rats with dual cholinergic-DA losses ("DL rats") were previously demonstrated to model PD falls and associated impairments of gait and balance. OBJECTIVES: We previously found that the muscarinic M1-positive allosteric modulator (PAM) TAK-071 improved the attentional performance of rats with BF cholinergic losses. Here, we tested the hypotheses that TAK-071 reduces fall rates in DL rats. RESULTS: Prior to DL surgery, female rats were trained to traverse a rotating straight rod as well as a rod with two zigzag segments. DL rats were refamiliarized with such traversals post-surgery and tested over 7 days on increasingly demanding testing conditions. TAK-071 (0.1, 0.3 mg/kg, p.o.) was administered prior to daily test sessions over this 7-day period. As before, DL rats fell more frequently than sham-operated control rats. Treatment of DL rats with TAK-071 reduced falls from the rotating rod and the rotating zigzag rod, specifically when the angled part of the zigzag segment, upon entering, was at a steep, near vertical angle. CONCLUSIONS: TAK-071 may benefit complex movement control, specifically in situations which disrupt the patterning of forward movement and require the interplay between cognitive and motor functions to modify movement based on information about the state of dynamic surfaces, balance, and gait.

McN-A-343, a muscarinic agonist, reduces inflammation and oxidative stress in an experimental model of ulcerative colitis.

AIM: The aim of the present study was to investigate the anti-inflammatory response mediated of the M1 muscarinic acetylcholine receptor (mAChR) during experimental colitis. MATERIAL AND METHODS: After the induction of 6% acetic acid colitis, mice were treated with McN-A-343 0.5, 1.0, and 1.5 mg/kg or dexamethasone (DEXA, 2.0 mg/kg) or pirenzepine (PIR, 10 mg/kg; M1 mAChR antagonist). Colonic inflammation was assessed by macroscopic and microscopic lesion scores, colonic wet weight, myeloperoxidase (MPO) activity, interleukin-1 beta (IL1-ß) levels and tumor necrosis factor alpha (TNF-α), glutathione (GSH), malondialdehyde (MDA) and nitrate and nitrite (NO3/NO2), mRNA expression of IKKα, nuclear factor kappa beta (NF-kB) and cyclooxygenase-2 (COX-2), as well protein expression of NF-kB and COX-2. RESULTS: Treatment with McN-A-343 at a concentration of 1.5 mg/kg showed a significant reduction in intestinal damage as well as a decrease in wet weight, MPO activity, pro-inflammatory cytokine concentration, markers of oxidative stress and expression of inflammatory mediators. The action of the M1 agonist by the administration of pirenzepine, which promoted the blocking of the mAChR M1-mediated anti-inflammatory response, has also been proven. CONCLUSION: The results suggest that peripheral colonic M1 mAChR is involved in reversing the pro-inflammatory effect of experimentally induced colitis, which may represent a promising therapeutic alternative for patients with ulcerative colitis.

An adenoviral vector encoded with the GPx-1 gene attenuates memory impairments induced by ß-amyloid (1-42) in GPx-1 KO mice via activation of M1 mAChR-mediated signalling.

In the present study, we examined whether glutathione peroxidase-1 (GPx-1), a major H2O2 scavenger in the brain, affects memory deficits induced by Aß (1-42) in mice. Treatment with 400 pmol/5 µl Aß (1-42) (i.c.v.) resulted in a reduction of GPx-1 expression in wild-type (WT) mice. An Aß (1-42)-induced reduction in acetylcholine (ACh) level was observed in the hippocampus. Treatment with Aß (1-42) consistently resulted in reduced expression and activity of choline acetyltransferase (ChAT) and in an increase in expression and activity of acetylcholinesterase (AChE). Upon examining each of the muscarinic acetylcholine receptors (mAChRs) and nicotinic AChRs, we noted that Aß (1-42) treatment selectively reduced the levels of M1 mAChR. In addition, Aß (1-42) induced a significant reduction in phospho-cAMP response element-binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) expression. The cholinergic impairments induced by Aß (1-42) were more pronounced in GPx-1 knockout mice than in WT mice. Importantly, an adenoviral vector encoded with the GPx-1 gene (Ad-GPx-1) significantly rescued Aß (1-42)-induced cholinergic impairments in GPx-1 knockout mice. In addition, M1 mAChR antagonist dicyclomine significantly counteracted Ad-GPx-1-mediated increases in p-CREB and BDNF expression, as well as memory-enhancing effects in GPx-1 knockout mice, thus indicating that M1 mAChR might be a critical mediator for the rescue effects of Ad-GPx-1. Combined, our results suggest that GPx-1 gene protected against Aß (1-42)-induced memory impairments via activation of M1 mAChR-dependent CREB/BDNF signalling.

Hippocampal knockdown of α2 nicotinic or M1 muscarinic acetylcholine receptors in C57BL/6J male mice impairs cued fear conditioning.

Acetylcholine (ACh) signaling in the hippocampus is important for behaviors related to learning, memory and stress. In this study, we investigated the role of two ACh receptor subtypes previously shown to be involved in fear and anxiety, the M1 mAChR and the α2 nAChR, in mediating the effects of hippocampal ACh on stress-related behaviors. Adeno-associated viral vectors containing short-hairpin RNAs targeting M1 or α2 were infused into the hippocampus of male C57BL/6J mice, and behavior in a number of paradigms related to stress responses and fear learning was evaluated. There were no robust effects of hippocampal M1 mAChR or α2 nAChR knockdown (KD) in the light/dark box, tail suspension, forced swim or novelty-suppressed feeding tests. However, effects on fear learning were observed in both KD groups. Short term learning was intact immediately after training in all groups of mice, but both the M1 and α2 hippocampal knock down resulted in impaired cued fear conditioning 24 h after training. In addition, there was a trend for a deficit in contextual memory the M1 mAChR KD group 24 h after training. These results suggest that α2 nicotinic and M1 muscarinic ACh receptors in the hippocampus contribute to fear learning and could be relevant targets to modify brain circuits involved in stress-induced reactivity to associated cues.

Muscarinic receptors promote castration-resistant growth of prostate cancer through a FAK-YAP signaling axis.

Prostate cancer (PCa) innervation contributes to the progression of PCa. However, the precise impact of innervation on PCa cells is still poorly understood. By focusing on muscarinic receptors, which are activated by the nerve-derived neurotransmitter acetylcholine, we show that muscarinic receptors 1 and 3 (m1 and m3) are highly expressed in PCa clinical specimens compared with all other cancer types, and that amplification or gain of their corresponding encoding genes (CHRM1 and CHRM3, respectively) represent a worse prognostic factor for PCa progression free survival. Moreover, m1 and m3 gene gain or amplification is frequent in castration-resistant PCa (CRPC) compared with hormone-sensitive PCa (HSPC) specimens. This was reflected in HSPC-derived cells, which show aberrantly high expression of m1 and m3 under androgen deprivation mimicking castration and androgen receptor inhibition. We also show that pharmacological activation of m1 and m3 signaling is sufficient to induce the castration-resistant growth of PCa cells. Mechanistically, we found that m1 and m3 stimulation induces YAP activation through FAK, whose encoding gene, PTK2 is frequently amplified in CRPC cases. Pharmacological inhibition of FAK and knockdown of YAP abolished m1 and m3-induced castration-resistant growth of PCa cells. Our findings provide novel therapeutic opportunities for muscarinic-signal-driven CRPC progression by targeting the FAK-YAP signaling axis.

Activation of muscarinic acetylcholine receptor 1 promotes invasion of hepatocellular carcinoma by inducing epithelial-mesenchymal transition.

Hepatocellular carcinoma is the second leading cause of cancer-related death worldwide. Neural regulation plays an important role in the development of hepatocellular carcinoma, and activation of sympathetic nervous system can promote the migration and invasion of cancer cells. However, little research has been conducted on how the vagus nerve influences hepatocellular carcinoma. In this study, we found that the expression of vesicular acetylcholine transporter, a biomarker of vagus nerve, was associated with hepatocellular carcinoma patients' clinicopathological characteristics by immunohistochemistry. Further, activation of muscarinic acetylcholine receptor 1 (M1R) promoted HepG2 and SMMC-7721 cells migration and invasion and epithelial-mesenchymal transition via PI3K/Akt pathway. Moreover, inhibition of M1R by antagonist or shRNA suppressed hepatocellular carcinoma cells migration and invasion in vitro and in vivo, inhibited epithelial-mesenchymal transition and PI3K/Akt pathway. Therefore, these results indicate that activation of M1R promotes invasion of hepatocellular carcinoma through epithelial-mesenchymal transition and PI3K/Akt pathway.