Inhibitory role of cholinergic system mediated via alpha7 nicotinic acetylcholine receptor in LPS-in

[lansbergen]

http://www.ncbi.nlm.nih.gov/pubmed/19586999

Innate Immun. 2010 Feb;16(1):3-13. doi: 10.1177/1753425909104680. Epub 2009 Jul 8.
Inhibitory role of cholinergic system mediated via alpha7 nicotinic acetylcholine receptor in LPS-induced neuro-inflammation.

Tyagi E, Agrawal R, Nath C, Shukla R.
Division of Pharmacology, Central Drug Research Institute, Lucknow, India.
Abstract

This study investigated the influence of the cholinergic system on neuro-inflammation using nicotinic and muscarinic receptor agonists and antagonists. Intracerebroventricular (ICV) injection of lipopolysaccharide (LPS, 50 microg) was used to induce neuro-inflammation in rats and estimations of pro-inflammatory cytokines, alpha7 nicotinic acetylcholine receptor (nAChR) mRNA expression were done in striatum, cerebral cortex, hippocampus and hypothalamus at 24 h after LPS injection. Nicotine (0.2, 0.4 and 0.8 mg/kg, i.p.) or oxotremorine (0.2, 0.4 and 0.8 mg/kg, i.p.) were administered 2 h prior to sacrifice. We found that only nicotine was able to block the proinflammatory cytokines induced by LPS whereas, oxotremorine was found ineffective. Methyllycaconitine (MLA; 1.25, 2.5 and 5 mg/kg, i.p.), an alpha7 nAChR antagonist or dihydro-beta-erythroidine (DHbetaE; 1.25, 2.5 and 5 mg/kg, i.p.), an alpha4beta2 nAChR antagonist, was given 20 min prior to nicotine in LPS-treated rats. Methyllycaconitine antagonized the anti-inflammatory effect of nicotine whereas DHbetaE showed no effect demonstrating that alpha7 nAChR is responsible for attenuation of LPS-induced pro-inflammatory cytokines. This study suggests that the inhibitory role of the central cholinergic system on neuro-inflammation is mediated via alpha7 nicotinic acetylcholine receptor and muscarinic receptors are not involved.

 

[lansbergen]

Dan heb ik er nog wat meer voor je.

http://www.eurekaselect.com/97182/article

http://onlinelibrary.wiley.com/doi/10.1111/j.1476-5381.2010.01034.x/pdf

http://www.ncbi.nlm.nih.gov/pubmed/21790533

http://www.jneurosci.org/content/32/22/7651.long

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3023065/

http://www.ncbi.nlm.nih.gov/pubmed/21294583

http://molpharm.aspetjournals.org/content/early/2012/07/24/mol.112.080317.full.pdf+html

http://www.jneuroinflammation.com/content/pdf/1742-2094-9-98.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3023065/

http://www.hzdr.de/db/Cms?pNid=2590

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031361

 

[lansbergen]

En deze

http://www.jbc.org/content/285/47/36542.full.pdf

Role of
7 Nicotinic Acetylcholine Receptor in Calcium
Signaling Induced by Prion Protein Interaction with
Stress-inducible Protein 1*

 

[lansbergen]

Int J Immunopathol Pharmacol. 2009 Apr-Jun;22(2):461-72.
Structure and function of the nicotinic arm of acetylcholine regulatory axis in human leukemic T cells.

Chernyavsky AI, Arredondo J, Galitovskiy V, Qian J, Grando SA.
Center for Immunology and Departments of Dermatology and Biological Chemistry, University of California, Irvine, CA, USA.
Abstract

Although acetylcholine (ACh) is widely known as a neurotransmitter, it also functions as a local humoral factor translating environmental stimuli into alterations in T cell development and function. The cholinergic components present in neurons are expressed in T cells where they constitute an independent cholinergic system. Both non-immunologic and immunologic stimulations can alter expression and function of cholinergic elements in T cells. Recent studies have convincingly demonstrated regulation of immune system by auto/paracrine ACh, which provides a basis for development of new immunomodulatory therapies with nicotinic agonists. The purpose of our research is to integrate information about the structure and activity of the ACh regulatory axis with the phenotypic and functional alterations of T cells during their development and commitment. In this study, we used the Ach producing human leukemic T cell line CCRF-CEM (CEM) to investigate auto/paracrine mechanisms of T cell regulation through the nicotinic class of ACh receptors (nAChRs). The intact CEM expressed alpha3, alpha5, alpha6, alpha7, alpha 9, beta2 and beta4 nAChR subunits. Stimulation of CEM with 10 microg/ml of phytohemagglutinin (PHA) for 16 h upregulated expression of the alpha3, alpha5, alpha7, alpha9 and beta2 and downregulated that of alpha6 and beta4 subunits, indicating that TCR activation leads to overexpression of high Ca2+-permeable ACh-gated ion channels. Activation of alpha7- and alpha3 AChRs predominantly abrogated PHA-dependent upregulation of the pro-inflammatory cytokine TNF-alpha and IFN-gamma receptors, respectively, at the mRNA and protein levels. Signaling through alpha7 and alpha3 nAChRs also significantly (p<0.05) altered expression of the cell state regulators p21 and Bcl-2, respectively, suggesting that downregulation of inflammation via nAChRs includes effects on the T cell cycle progression and apoptosis. These findings indicate that constant stimulation of alpha7 and alpha3 nAChRs by endogenously released ACh controls T cell activation and that signaling downstream of distinct nAChR subtypes targets specific inflammatory and cell cycle genes. Learning the cholinergic pharmacology of inflammation should allow to regulate specific types of immune reactions by selectively activating or blocking the types of nAChRs expressed by the immune cells mediating specific immune reactions.

 

[lansbergen]

http://www.ncbi.nlm.nih.gov/pubmed/19632243
Life Sci. 2009 Sep 9;85(11-12):444-9. doi: 10.1016/j.lfs.2009.07.010. Epub 2009 Jul 24.
Alpha 7 nicotinic acetylcholine receptor modulates lymphocyte activation.

De Rosa MJ, Dionisio L, Agriello E, Bouzat C, Esandi Mdel C.
Source

Instituto de Investigaciones Bioquímicas de Bahía Blanca, UNS-CONICET, Camino La Carrindanga Km7, B8000FWB Bahía Blanca, Argentina.
Abstract

AIMS:

Even though the presence of alpha7 nicotinic receptor (nAChR) in lymphocytes has been demonstrated, its functional role still remains elusive. The aim of our study was to characterize alpha7 nAChRs in human lymphocytes upon phytohemagglutinin (PHA) stimulation.

MAIN METHODS:

Lymphocytes were activated with the mitogen PHA. alpha7 nAChRs were studied by reverse transcription-polymerase chain reaction (RT-PCR), real time PCR, flow cytometry and confocal laser scanning microscopy. The effects of nicotinic drugs on PHA-induced proliferation was evaluated by the [(3)H]-thymidine incorporation assay.

KEY FINDINGS:

We show that the expression of functional alpha7 receptors increases after PHA stimulation. The activation of peripheral lymphocytes by PHA increases 2.2-fold the alpha7 subunit mRNA expression and 4-fold the binding of the antagonist alpha-bungarotoxin (alpha-BTX) with respect to non activated lymphocytes. By measuring the increase of intracellular calcium in response to nicotine we determine that alpha7 receptors in lymphocytes are functional. Nicotinic drugs differentially modulate T cell activation. While nicotine tends to inhibit proliferative responses, specific alpha7 antagonists, such as alpha-BTX and methyllycaconitine, enhance cell division.

SIGNIFICANCE:

This study reveals that the alpha7 receptor modulates lymphocyte activation and contributes to clarifying the role of the non neuronal cholinergic system in the immune response.

 

[lansbergen]

http://www.ncbi.nlm.nih.gov/pubmed/21911260
J Neuroimmunol. 2011 Oct 28;239(1-2):37-43. doi: 10.1016/j.jneuroim.2011.08.007. Epub 2011 Sep 10.
Role of α7 nicotinic acetylcholine receptors in regulating tumor necrosis factor-α (TNF-α) as revealed by subtype selective agonists.

Li J, Mathieu SL, Harris R, Ji J, Anderson DJ, Malysz J, Bunnelle WH, Waring JF, Marsh KC, Murtaza A, Olson LM, Gopalakrishnan M
Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, United States.

Abstract

Immunological responses to protect against excessive inflammation can be regulated by the central nervous system through the cholinergic anti-inflammatory pathway wherein acetylcholine released from vagus nerves can inhibit inflammatory cytokines. Although a role for the α7 nicotinic acetylcholine receptor (α7 nAChR) in mediating this pathway has been suggested, pharmacological modulation of the pathway by selective agonists remains to be further elucidated. In this study, the role of α7 nAChRs in the regulation of TNF-α release was investigated using high affinity and selective α7 nAChR agonists in mouse peritoneal macrophage and human whole blood in vitro, and in mouse serum in vivo. In mouse peritoneal macrophages, LPS-induced TNF-α release in vitro was inhibited by a selective α7 nAChR agonist, A-833834 (5-[6-(5-Methyl-hexahydro-pyrrolo[3,4-c]pyrrol-2-yl)-pyridazin-3-yl]-1H-indole), and that effect was attenuated by α7 nAChR antagonist methyllycaconitine. The inhibitory effect of A-833834 on LPS-induced TNF-α release was also observed in human whole blood in vitro. I.v. LPS-induced TNF-α release in mouse serum was attenuated following i.p. administration of A-833834. Similarly, i.v. LPS-induced TNF-α release in mouse serum was also attenuated following i.p. administration of A-585539, another α7 nAChR agonist with limited brain penetration, suggesting that these effects are mediated by peripheral α7 nAChRs. A-833834 was also efficacious in suppressing TNF-α release in mouse serum following oral administration in zymosan-induced peritonitis. These studies collectively demonstrate that selectively targeting α7 nAChRs could offer a novel therapeutic modality to treat acute and chronic inflammatory disease states.

 

[alex3619]

All fascinating research. I have a blog planned for LPS next year, I have been working on it for months but there are so many issues to take into account.

I wonder if this is linked to the anecdotal observation I heard from one doctor that CFS patients who were smokers almost never showed improvement in his practice?

I have recently been looking at the intracellular side of this. Phosphodiesterase features heavily in my view of all this. I think it may be overactivated in us, leading to excessive biochemical responses. Simply blocking this with drugs could be problematic though ... half of all the biochemistry in the body is probably affected by phosphodiesterases. Thats a big range of potential side effects.

I am currently trying resveratrol in pulsed low doses. I have yet to make up my mind on how well it is working.

I do wonder if LPS might not be driving the increased activity though. I am still investigating. Dealing with TNFalpha is coming up a lot in my reading.

Let me point out that an increase in phosphodiesterase activity can induce hypersomnia.

 

[lansbergen]

http://jpet.aspetjournals.org/content/335/3/553.long

Stimulation of α7 Nicotinic Acetylcholine Receptor by Nicotine Increases Suppressive Capacity of Naturally Occurring CD4+CD25+ Regulatory T Cells in Mice In Vitro

Da-wei Wang, Rong-bin Zhou, Yong-ming Yao, Xiao-mei Zhu, Yi-mei Yin, Guang-ju Zhao, Ning Dong and hi-yong Sheng
Emergency Department, General Hospital of Beijing Military Area Command, Beijing, People's Republic of China (D.W., R.Z., Y.Ya.); and Department of Microbiology and Immunology, Burns Institute, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, People's Republic of China (D.W., Y.Ya., X.Z., Y.Yi., G.Z., N.D., Z.S.)
http://jpet.aspetjournals.org/content/335/3/553.long#sec-1
Abstract

α7 Nicotinic acetylcholine receptor (α7 nAChR) has been found in several non-neuronal cells and is described as an important regulator of cellular function. Naturally occurring CD4+CD25+ regulatory T cells (Tregs) are essential for the active suppression of autoimmunity. The present study investigated whether naturally occurring Tregs expressed α7 nAChR and investigated the functionary role of this receptor in controlling suppressive activity of these cells. We found that CD4+CD25+ Tregs from naive C57BL/6J mice positively expressed α7 nAChR, and its activation by nicotine enhanced the suppressive capacity of Tregs. Nicotine stimulation up-regulated the expression of cytotoxic T-lymphocyte-associated antigen (CTLA)-4 and forkhead/winged helix transcription factor p3 (Foxp3) on Tregs but had no effect on the production of interleukin (IL)-10 and transforming growth factor-β1 by Tregs. In the supernatants of CD4+CD25+ Tregs/CD4+CD25− T-cell cocultures, we observed a decrease in the concentration of IL-2 in nicotine-stimulated groups, but nicotine stimulation had no effect on the ratio of IL-4/interferon (IFN)-γ, which partially represented T-cell polarization. The above-mentioned effects of nicotine were reversed by a selective α7 nAChR antagonist, α-bungarotoxin. In addition, the ratio of IL-4/IFN-γ was increased by treatment with α-bungarotoxin. We conclude that nicotine might increase Treg-mediated immune suppression of lymphocytes via α7 nAChR. The effect is related to the up-regulation of CTLA-4 as well as Foxp3 expression and decreased IL-2 secretion in CD4+CD25+ Tregs/CD4+CD25− T-cell coculture supernatants. α7 nAChR seems to be a critical regulator for immunosuppressive function of CD4+CD25+ Tregs.

 

[lansbergen]

http://www.jleukbio.org/content/81/5/1245.full
Modulation of eosinophil activation in vitro by a nicotinic receptor agonist

Marie-Renée Blanchet, Anick Langlois, Evelyne Israël-Assayag, Marie-Josée Beaulieu,Claudine Ferland, Michel Laviolette and Yvon Cormier1

1. Centre de Recherche, Hôpital Laval, Institut Universitaire de Cardiologie et de Pneumologie de l’Université Laval, Ste-Foy, Québec, Canada

Abstract

Nicotinic receptor agonists decreased the infiltration of eosinophils into the lung and airways in a mouse model of asthma. To better understand the mechanisms implicated in this anti-inflammatory phenomenon, the expression of nicotinic acetylcholine receptors (nAChRs) and the effect of dimethylphenylpiperazinium (DMPP), a nonselective nAChR agonist, on human blood eosinophils were studied. The expression of α-3, -4, and -7 nAChR subunits on human blood eosinophils was measured by cell ELISA and immunocytochemistry. mRNA expression for all three subunits was evaluated by quantitative RT-PCR. The effect of DMPP on leukotriene C4 (LTC4) and matrix metalloproteinase-9 (MMP-9) production, eosinophil migration, and intracellular calcium mobilization was measured. The results show that the α-3, -4, and -7 nAChR subunits and mRNAs are expressed by blood eosinophils. In vitro treatment of these cells with various concentrations of DMPP reduced platelet-activating factor (PAF)-induced LTC4 production significantly. DMPP (160 μM) decreased eotaxin, and 5-oxo-6,8,11,14-eicosatetranoic acid induced eosinophil migration through Matrigel by 40.9% and 55.5%, respectively. This effect was reversed by the nAChR antagonist mecamylamine. In addition, DMPP reduced MMP-9 release and the inositol 1,4,5-triphosphate-dependent intracellular calcium increase provoked by PAF. Taken together, these results indicate that functional nAChRs are expressed on eosinophils and that nAChR agonists down-regulate eosinophil function in vitro. These anti-inflammatory effects could be of interest in the treatment of allergic asthma.

 

[lansbergen]

http://www.ncbi.nlm.nih.gov/pubmed/11834293
Brain Res Mol Brain Res. 2002 Jan 31;98(1-2):29-40.
Absence of alpha7-containing neuronal nicotinic acetylcholine receptors does not prevent nicotine-induced seizures.

Franceschini D, Paylor R, Broide R, Salas R, Bassetto L, Gotti C, De Biasi M.
Division of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.

Abstract

Nicotine is the primary addictive component in tobacco, and at relatively low doses it affects cardiovascular responses, locomotor activity, thermoregulation, learning, memory, and attention. At higher doses nicotine produces seizures. The mechanisms underlying the convulsive effects of nicotine are not known, but studies conducted on a number of inbred strains of mice have indicated a positive correlation between the number of alpha-bungarotoxin (alpha-BTX) binding sites in the hippocampus and the sensitivity to nicotine-induced seizures. Because alpha7-containing neuronal nicotinic acetylcholine receptors (nAChRs) represent the major binding site for alpha-BTX, mice lacking the alpha7 nAChR subunit were predicted to be less sensitive to the convulsive effects of nicotine. To test this hypothesis, we injected nicotine intraperitoneally in alpha7 mutant mice and found that the dose-response curve for nicotine-induced seizures was similar in the alpha7 +/+, alpha7 +/- and alpha7 -/- mice. The retained sensitivity to the convulsant effects of nicotine could not be explained by the presence of cholinergic compensatory mechanisms such as increases in mRNA levels for other nAChR subunits, or changes in binding levels or affinity for nicotinic ligands such as epibatidine and nicotine. These findings indicate that alpha7 may not be necessary for the mechanisms underlying nicotine-induced seizures.

 

[alex3619]

Modulation of eosinophil activation in vitro by a nicotinic receptor agonist

One of the driving forces in this type of asthmatic response is PGD2. It drives increased phosphodiesterase-4. This in turn will massively increase an acetylcholine response by inhibiting opposition from cAMP responses. My recent investigation of these issues is along those lines. Known ME biochemistry will also cause issues with PGD2 expression.

The biochemistry all hangs together. This does not however help us in determining which paths and interpretations are most relevant. We need lab results to determine this.

This ties in with mast cell disorders as well, though I am not convinced that most of us have such a problem. I think the problem is in deeper biochemistry, not specific cell types like mast cells.

 

[lansbergen]

As I said before mastcell activation is a normal reaction to infection.
.

 

[Sing]

Translation, guys?

My understanding is that Mestinon (Pyridogstimine) is a nicotinic agonist and Aricept is a mescarinic agonist. Is this your understanding? Secondly, how would either of these affect the disease process or symptoms, and which ones? Can you made a guess? Would either or both of these drugs help or hinder us?

 

[lansbergen]

I use the allosteric a7 nAchR modulator levamisole.

As I understand it, stimulating this receptor decreases inflammation and improves brainworking.

It helps for all symptoms I had.

The a7 nAchR has more sites where small molecules like levamisole can bind to improve working.
There must be some out there that can do the job as good or better as levamisole.


http://en.wikipedia.org/wiki/Positive_allosteric_modulator

A positive allosteric modulator (PAM) is a drug which increases the activity of a receptor indirectly via activation of an allosteric site on the protein. PAMs are similar to agonists in that they contribute to overall receptor activation, but they are different because they do so in a functionally distinctive way

 

[Sing]

Levamerisole according to wikipedia doesn't sound good to me. http://en.wikipedia.org/wiki/Levamisole

 

[lansbergen]

Levamerisole according to wikipedia doesn't sound good to me. http://en.wikipedia.org/wiki/Levamisole

Depends on dosis. High dosis can kill. It is dangerous in the wrong hands and in combination with some other substances.

For me it was a livesaver.

As I used it in animals for decades and sometimes spilled it on my skin it was a calculated gamble for me and I was dying anyway.

I tried to speed up recovering by increasing the dosis and/or freqency but that did not become me.

I think it is still on the WHO list of essential meds.

 

[Sing]

Thanks for explaining! We have been so much on our own, both understanding this illness and trying to work out treatments. I hope this is changing and that more scientists and doctors will be interested and help.

I wonder if Mestinon (Pyridogstimine) does the same thing, in terms of being a nicotinic receptor agonist?

What symptoms did you have that the Levamerisole helped with and what were the effects of this treatment?

 

[lansbergen]

I wonder if Mestinon (Pyridogstimine) does the same thing, in terms of being a nicotinic receptor agonist?

What symptoms did you have that the Levamerisole helped with and what were the effects of this treatment?

I do not know Mesinon will help but you could start with trying nicotine patches.

I need both nicotine from smoking as the agonist and levamisole as the PAM.

 

[lansbergen]

Symptoms i hated most:

Horrible umbearable pain.
Brain problems.
Muscle refused to do what I wanted. At times losing all musclestrengh so I fell flat on the floor. Neck not strong enough to carry head.
Heartracing wich several times caused sudden stopping heartbeat.
Severe breathing problems. Lower lunglobs did not work and upper lobs barely worked.
Sudden sweating for no reason.

 

[adreno]

Sounds very dramatic and serious. Never tried anything like it!