Atropine can induce autophagy independent of the M3 muscarinic acetylcholine receptor

Background: No other effects of atropine other than as an antagonist of muscarinic acetylcholine receptor (mAChR) have been found. Methods: In this study, human kidneyepithelial cells were treated with different physiological regulators. Results: Subsequently, it was found that atropine could significantly induce autophagy as demonstrated by the appearance of autophagosome-like double- or single-membrane vesicles in the cytoplasm ofhost cells and the number of GFP-LC3 dots. In addition, increased conversion of the autophagy marker protein LC3-I and LC3-II and increased p62/SQSTM1 indicatedincomplete autophagy. In addition, atropine induced autophagosome levels in a dose-dependent manner within a certain concentration range in human kidney epithelial cells. In atropine-treated mouse skeletal muscle cells containing nicotinic acetylcholinereceptors and rat cardiac muscle cells containing mAchR, atropine induced autophagy in mouse skeletal muscle cells but not in rat cardiac muscle cells. Furthermore, atropine did not induce autophagy in tissue cells containing mAchR in vivo but did in tissue cells not containing mAchR. Conclusion: This study expands the application and understanding of atropine’s action mechanism in the field of medicine.

Anisodine hydrobromide alleviates oxidative stress caused by hypoxia/reoxygenation in human cerebral microvascular endothelial cells predominantly via inhibition of muscarinic acetylcholine receptor 4

Background:Anisodine hydrobromide(AT3),an anti-cholinergic agent,could be delivered to the brain across the blood-brain barrier and has been used clinically for the treatment of cerebral ischemia/reperfusion injury.Endothelial dysfunction can be caused by hypoxia/reoxygenation(H/R)via oxidative stress and metabolic alterations.The present study investigated whether AT3 regulates the production of nitric oxide(NO)and reactive oxygen species(ROS),and the HIF-1αpathway via regulation of muscarinic acetylcholine receptors(mAChRs)in brain microvascular endothelial cells after H/R exposure.Methods:Under H/R conditions,hCMEC/D3 cerebral microvascular endothelial cells were treated with AT3.Specific inhibitors of M2-and M4-mAChRs were used to explore the mechanism by which AT3 influences oxidative stress in endothelial cells.Then,mAChRs expression was detected by western blotting and NO production was detected by Greiss reaction.The intracellular ROS level was measured using DCFH-DA probes.The expression of hypoxia-inducible transcription factor 1α(HIF-1α)was also detected.Results:While H/R induced the expression of M2-and M4-mAChRs,AT3 suppressed the H/R-upregulated M2-and M4-mAChRs.H/R also induced the production of NO,ROS,and apoptosis.AT3 and M4-mAChR inhibitors inhibited the H/R-induced production of NO and ROS and apoptosis.HIF-1αwas induced by H/R,but was suppressed by AT3.Conclusion:Thus,the in vitro evidence shows that AT3 protects against H/R injury in cerebral microvascular endothelial cells via inhibition of HIF-1α,NO and ROS,predominantly through the downregulation of M4-mAChR.The findings offer novel understandings regarding AT3-mediated attenuation of endothelial cell apoptosis and cerebral ischemia/reperfusion injury.

Effects of gamma-aminobutyric acid receptors on muscarinic receptor-mediated free calcium ion levels in the facial nucleus following facial nerve injury

Muscarinic receptors and nicotine receptors can increase free calcium ion levels in the facial nucleus via different channels following facial nerve injury. In addition, γ-aminobutyric acid A （GABAA） receptors have been shown to negatively regulate free calcium ion levels in the facial nucleus by inhibiting nicotine receptors. The present study investigated the influence of GABAA, γ-aminobutyric acid B （GABAB） and C （GABAc） receptors on muscarinic receptors in rats with facial nerve injury by confocal laser microscopy. GABAA and GABAB receptors exhibited significant dose-dependent inhibitory effects on increased muscarinic receptor-mediated free calcium ion levels following facial nerve injury. Results showed that GABAA and GABAB receptors negatively regulate muscarinic receptor effects and interplay with cholinergic receptors to regulate free calcium ion levels for facial neural regeneration.

Potencies of Four Stereoisomers of Anisodamine on Muscarinic Receptor

用[3~H]-QNB配体受体结合实验,抗Ach对豚鼠回肠纵肌条收缩效应,抗毛果芸香碱流涎及扩瞳效应为指标,比较山莨菪碱四个立体异构体(A.6S,2′S;B.6S,2′R;C.6R,2′R;D.6R,2′S)与M受体相互作用的构效关系,结果A,B,C,D四个异构体效应分别为:(1)受体结合实验K_i(M)2.69×10^(-7),1.43×10^(-7),1.63×10^(-5),2.15×10^(-6);(2)抗Ach豚鼠回肠纵条收缩:K_6(M)2.98×10^(-8);1.38×10^(-8);1.52×10~5;1.0l×10^(-7);(3)扩瞳:ED_4(mol/kg)1.6×10^(-6),1.9×10^(-6),5.1×10^(-5),3.6×10^(-5);(4)抗毛果芸香碱流涎:ED_(50)(mol/kg)1.5×10^(-6);1.3×10^(-6);2.6×10^(-5);3.1×10^(-5)。以上结果表明四个异构体效应强度为6S,2′R≌6S,2′S>>6R,2′S>6R,2′R。

Effect of green flickering light on myopia development and expression of M1 muscarinic acetylcholine receptor in guinea pigs

AIM： To investigate the effects of green flickering light on refractive development and expression of muscarinic acetylcholine receptor（mAChR） M1 in the eyes of guinea pigs.METHODS： Thirty guinea pigs（15-20 days old） were randomly divided into three groups（n=10/group）. Animals in group I were raised in a completely closed carton with green flickering light illumination. Those in group II were kept in the open top closed carton under normal natural light. Guinea pigs were raised in a sight-widen cage under normal natural light in group III. The refractive status and axial length were measured before and after 8 weeks＇ illumination. Moreover, total RNA extracted from retinal, choroidal, and scleral tissues were determined by real-time reverse transcription polymerase chain reaction（RT-PCR）. The expressions of the receptor M1 were also explored in the retina, choroid, and sclera using immunohistochemistry.RESULTS： There was a remarkable reduction in refractive error and increase in axial length after 8-weeks＇ green flickering light stimulation（P〈0.001）. The expression of M1 receptor mRNA in sclera and retina in myopia group were remarkably lower than that in group II and III（P〈0.01）. Significant reduced expression of M1 receptor stimulated by green flickering light in retina and sclera tissues were also observed（P〈0.05）. However, there was no M1 receptor expression in choroid in 3 groups.CONCLUSION： Myopia can be induced by 8 weeks＇ green flickering light exposure in the animal model. M1 receptor may be involved causally or protectively in myopia development.

AduoLa Fuzhenglin Down-regulates Microwave-induced Expression of β_1-adrenergic Receptor and Muscarinic Type 2 Acetylcholine Receptor in Myocardial Cells of Rats

This paper is aimed to study the effect of ADL on expression of ~z-AR and Mz-AchR in myocardial cells of rats exposed to microwave radiation. Immunohistochemistry, Western blot and image analysis were used to detect the expression of ~I-AR and Mz-AchR in myocardial cells at 7 and 14 d after microwave exposure. The results show that the expression level was higher in microwave exposure group and 0.75 g/（kg.d） ADL group than in sham operation group and significantly lower in 1.5 and 3.0 g/（kg.d） ADL groups than in microwave group. So we have a conclusion that the expression of I^z-AR and Mz-AchR is down-regulated in myocardial cells of rats exposed to microwave radiation. ADL can protect rats against microwave-induced heart tissue injury.

Microinjection of M_5 muscarinic receptor antisense oligonucleotide into VTA inhibits FosB expression in the NAc and the hippocampus of heroin sensitized rats

Objective To investigate the effect of M5 muscarinic receptor subtype on the locomotor sensitization induced by heroin priming, and it＇s effect on the FosB expression in the nucleus accumbens （NAc） and the hippocampus in the heroin sensitized rats. Methods Locomotor activity was measured every 10 min for 1 h after subcutaneous injection of heroin. FosB expression was assayed by immunohistochemistry, and the antisense oligonucleotides （AS-ONs） targeting M5 muscarinic receptor was transferred with the lipofectin. Results Microinjection of AS-ONs targeting M5 muscarinic receptor in the ventral tegmental area （VTA） blocked the expression of behavioral sensitization induced by heroin priming in rats. Meanwhile, the expression of FosB-positive neurons in either the NAc or the dentate gyrus （DG） of the hippocam- pus increased in heroin-induced locomotor sensitized rats. The enhancement of FosB-positive neurons in the NAc or DG could be inhibited by microinjection of M5 muscarinic receptor AS-ONs into the VTA before the heroin-induced locomotor sensitization was performed. In contrast, microinjection of M5 muscarinic receptor sense oligonucleotide （S-ONs） into the VTA did not block the expression of behavioral sensitization or the expression of FosB in the NAc or DG in the heroin sensitized rats. Conclusion Blocking M5 muscarinic receptor in the VTA inhibits the expression of heroin-induced locomotor sensitization, which is associated with the regulation of FosB expression in the NAc and hippocampus neurons. M5 muscarinic receptor may be a useful pharmacological target for the treatment of heroin addiction.

M3 Muscarinic Acetylcholine Receptor Antagonist Darifenacin Protects against Pulmonary Fibrosis through ERK/NF-κB/miR-21 Pathway

Idiopathic pulmonary fibrosis is an untreatable lethal lung disease, which is related to the aberrant proliferation of fibroblasts. M3 muscarinic acetylcholine receptor (M3-mAChR) activation exerts proliferative effect on various kinds of cells. However, whether M3-mAChR inhibition has a protective effect on pulmonary fibrosis remains unexplored. A rat model of pulmonary fibrosis was established by intratracheal instillation of bleomycin. Darifenacin was used to block M3-mAChR. Histological changes were observed using Masson’s Trichrome and hematoxylin and eosin (HE) staining. Hydroxyproline was measured by Hydroxyproline detection kit. Transforming growth factor β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). In vitro, pulmonary fibroblasts were isolated from lungs of neonatal rat. After treatment, the cell viability, Hydroxyproline level was measured by MTT and Hydroxyproline detection kit respectively. The expression level of extracellular signal-regulated kinase (ERK), nuclear factor kappa-B (N-NF-κB), and microRNA-21 (miR-21) was detected by western blot or quantitative real-time PCR (qRT-PCR). Darifenacin relieved the fibrotic effects provoked by bleomycin. The expression level of hydroxyproline, TGF-β1 and TNF-α level was all downregulated after darifenacin treatment. In lung fibroblasts, darifenacin decreased cell viability and hydroxyproline level induced by bleomycin. Besides, phosphorylation-ERK and nuclear N-NF-κB protein level was downregulated, as well as miR-21 level. M3-mAChR antagonist darifenacin attenuates bleomycin-induced pulmonary fibrosis in rats, which may relate to the ERK/NF-κB/miRNA-21 signaling pathway.

METABOLIC KINETICS OF BRAIN MUSCARINIC CHOLINERGIC RECEPTORS IN NORMAL AND HYPOTHYROID MICE

A technique for studying in vivo the production rate and turnover rate constant of mouse brain M-receptors was established. A single injection of 25 mg / kg of Benzilylcholine Mustard to living mice resulted in 90 % irreversible block of brain M-receptors. The time course of the receptor density was then monitored by 3H-QNB binding assay and the production rate and turnover rate constant were calculated from the time course curve with a computer program. It was found that in normal mice the turnover rate constant was about 0.035 h-1 (half-life was about 20 h) and the production rate was 30-42 fmol / (h ·mg protein). Parallel experiments revealed a significant slow down of the turnover of brain M-receptors in hypothyroid mice (turnover rate constant was 0.0257±0.0012 h-1 in hypothyroid vs. 0.0356±0.0021 h-1 in normal) while the production rate was not changed significantly. The results suggest that thyroid hormones have a regulatory action on the turnover of brain M-receptors and the elevation of brain M-receptor density together with slow down of the turnover of brain M- receptors is probably one of the important mechanisms relevant to the brain dysfunction in hypothyroidism.

M_(4) muscarinic receptors regulates dopamine/DARPP-32 signaling and glutamate transmis⁃sion to balance dopaminergic D1 function in mouse dorsal striatum

OBJECTIVE Abnormal striatal dopaminergic and glutamatergic neurotransmis⁃sion is central to the pathophysiology of schizo⁃phrenia.In this study,we investigated the roles of M4 receptor interplay with D1 signaling in stria⁃tal neurotransmission that affect glutamatergic transmission to control the etiology of neuropsy⁃chiatric disorders.METHODS To study dorsal striatum(DS)region-specific neuronal and behav⁃ioral responses modulated by M4 receptors,we used clustered regularly interspaced short palin⁃dromic repeats-associated protein 9 technology to generate mice lacking M4 in the dorsal stria⁃tum(DS-M4-KD).The M4 positive allosteric modu⁃lator,VU0467154,were used to study the phar⁃macologically profiles with M4 receptor stimula⁃tion in WT mice.Oxotremorine M(Oxo-M),a no subtype-selective muscarinic agonist,was used to show that mAchRs activation,in order to dissect the particular function of M4,in DS-M4-KD mice.Open filed test and forced swim test were used to assess the change of psychiatric-like behav⁃iors.Western blotting and immunohistochemistry were used to detect protein levels of phosphory⁃lation site of dopamine-and cAMP-regulated phosphoprotein of 32 ku(DARPP-32).Whole-cell patch-clamp recording was used to assess M4-mediated cholinergic inhibition of glutamater⁃gic synaptic input transmission.RESULTS West⁃ern blotting and immunohistochemistry assay showed VU0467154(5 mg·kg-1,ip)promoted phosphorylation of DARPP-32 at Thr75,and atten⁃uated D1-dependent phosphorylation of DARPP-32 at Thr34 within the mouse DS.Consistently,the Oxo-M(4μg,icv)also increased DARPP-32 phosphorylation at site Thr75 to reversed phos⁃phorylation at site Thr34 in WT mice,but not in DS-M4-KD mice.In parallel with altered DARPP-32 responses,VU0467154 or Oxo-M evoked a psychological stress response and reversed D1-induced hyperlocomotion in mice in open field test and force swim tests.However,Oxo-M sup⁃pression of D1-depengdeng behavioral respons⁃es was impaired in DS-M4-KD mice.Whole-cell patch recording showed that VU0467154 or Oxo-M mediated endogenous cholinergic inhibition of miniature excitatory postsynaptic currents through M4 receptors,which in turn suppressed D1-depen⁃dent glutamatergic synaptic transmission in the DS.CONCLUSION This study provides evidence for the role of M4 receptors in regulation of dopa⁃mine/DARPP-32 signaling and glutamate respons⁃es in the DS,and therefore modulation of psychi⁃atric behaviors associated with D1 signaling.This results indicate the mechanisms of treatments targeting M4 in psychiatric disorders.

Effect of organophosphorus insecticides on phosphorylation of the M_2 muscarinic acetylcholine receptor

BACKGROUND： Organophosphorus insecticides may promote the accumulation of acetylcholine at synapses and the neuromuscular junction by inhibiting acetylcholinesterase activity to cause disturbance of neural signal conduction and induce a toxic reaction. Organophosphorus insecticides may act on M2 muscarinic acetylcholine receptors, whose combination with G proteins is regulated by phosphorylation of G protein-coupled receptor kinase 2. OBJECTIVE： To investigate the effects of organophosphorus insecticides on the phosphorylation of G protein-coupled receptor kinase 2-mediated M2 muscarinic acetylcholine receptors and to reveal other possible actions of organophosphorus insecticides. DESIGN, TIME AND SETTING： An observational study, which was performed in the Central Laboratory of Shenyang Medical College, and Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University from June 2002 to December 2004. MATERIALS： Paraoxon, parathion, chlorpyrifos, and chlorpyrifos oxon were provided by Chem Service Company, USA, [γ -p^32] ATP and [^35S]GTP γ S by New England Nuclear Life Science Products, and recombinant β 2-adrenergic receptor membrane protein by Sigma Company, USA. METHODS： The M2 muscarinic acetylcholine receptor was extracted and purified from pig brain using affinity chromatography. Subsequently, the purified M2 muscarinic acetylcholine receptor, G protein-coupled receptor kinase 2, and [γ -p^32] ATP were incubated with different concentrations of paraoxon and chlorpyrifos oxon together. The mixture then underwent polyacrylamide gel electrophoresis, and the gel film was dried and radioactively autographed to detect phosphorylation of the M2 muscarinic acetylcholine receptor. Finally, the radio-labeled phosphorylated M2 receptor protein band was excised for counting with an isotope liquid scintillation counter. MAIN OUTCOME MEASURES： Effects of chlorpyrifos oxon, paraoxon, chlorpyrifos, and parathion in different concentrations on the phosphorylation of the M2 muscarinic acetylcholine receptor; effects of chlorpyrifos oxon on the phosphorylation of the β -adrenergic receptor. RESULTS： Chlorpyrifos oxon could completely inhibit the phosphorylation of the M2 muscarinic acetylcholine receptor, and its IC50 was 70 μ mol/L. Chlorpyrifos could also inhibit the phosphorylation of the M2 muscarinic acetylcholine receptor. However, paraoxon and parathion could not inhibit the phosphorylation of the M2 muscarinic acetylcholine receptor. Chlorpyrifos oxon in different concentrations could also not inhibit the phosphorylation of the β 2-adrenergic receptor catalyzed by G protein-coupled receptor kinase 2. CONCLUSION： Different kinds of organophosphorus insecticides have different effects on the phosphorylation of the G protein-coupled receptor kinase 2-mediated M2 muscarinic acetylcholine receptor. Organophosphorus insecticides possibly have different toxic effects.

Methanol extract of Desmodium gangeticum DC root mimetic post-conditioning effect in isolated perfused rat heart by stimulating muscarinic receptors

Objective:To evaluate pharmacological mimetic action of herbal extract Desmodium gangeticum (DC) roots on ischemia reperfusion injury.Methods:With the help of Langendroff perfusion technique,ischemic post condition(POC) mimetic action of DG methanol root extract was evaluated and compared by using standard drugs that acts as muscarinic receptor agonist and antagonist,namely acetylcholine(Ach) and atropine(Atr) respectively in an isolated rat heart. Results:The physiological parameters like left ventricular developed pressure,end diastolic pressure and working index of isolated rat heart showed significant recovery in DG root extract administrated rat heart,similar to the recovery by POC.Kymogram results showed muscarinic receptor agonist like action for DG methanol root extract,confirmed in rat heart by muscarnic receptor agonist(acetylcholine) and anatoginst(atropine).Administration of DC root extract prior to reperfusion showed better antioxidant status in myocardial tissue homogenate and mitochondrial,complemented by the levels of cardiac specific marker proteins in myocardial tissue and perfusate.Even though DG methanol root extract mimics its action similar to that of Ach,the myocardial protection mediated by the extract was superior to Ach,due to the presence of antioxidants in the crude extract.Conclusions:DG methanol root extract provides myocardial protection towards IRI by stimulating muscarinic receptors.

Effect of Daicong solution on hippocampal muscarinic receptors 1 and 3 gene expression in a rat model of Alzheimer’s disease

BACKGROUND： It has been previously shown that the muscarinic （M） receptor is involved in brain arousal and selective attention, mood, and motor coordination. OBJECTIVE： To explore the effects of various intragastric Daicong doses on hippocampal MI and M3 receptor gene expression in a rat model of Alzheimer＇s disease. DESIGN, TIME AND SETTING： A randomized cellular and molecular biology experiment, conducted at the Molecular Immunology Laboratory in Shandong between October 2006 and April 2007. MATERIALS： Fifty 22-month old Sprague Dawley rats, weighing 250-300 g were used for this experiment. Kainic acid was used to lesion the nucleus basalis to establish a rat model of Alzheimer＇s disease. The components of Daicong solution were as follows： ginseng, rehmannia dride rhizome, anemarrhena, and radix astragali. The solution was provided by the Affiliated Hospital to Weifang Medical College, according to preparation techniques of extracting liquid for traditional Chinese medicine （1 g crude drug/mL solution）. Kainic acid was provided by Professor Xiuyan Li at Weifang Medical College. METHODS： The rats were randomly divided into 5 groups, 10 rats in each group. Four groups were used for model establishment, and the fifth group served as a normal control group. Three of the model groups were intragastrically administered 5, 10, and 20 g/kg/d Daicong solution, and an additional model group and normal control group received normal saline （10 mL/kg/d）. Drugs were administered over a time period of one month. MAIN OUTCOME MEASURES： Four days after model establishment, Morris water maze was used to measure learning and memory capabilities. RT-PCR was used to detect the effect of Daicong solution on mRNA expression of M1 and M3 receptor in the hippocampus of all groups. RESULTS： Fifty rats were included in the final analysis, without any loss. M1 and M3 receptor mRNA expression was decreased in the model group, compared to the normal control group （P 〈 0.05）. Upon Daicong administration （10 g/kg/d and 20 g/kg/d）, M1 and M3 receptor mRNA expression significantly increased in the hippocampus, compared to the model group （P 〈 0.05）. M1 and M3 mRNA expression was greatest in the 10 g/kg/d group. CONCLUSION： A 10 g/kg/d solution of Daicong can improve M1 and M3 receptor mRNA expression in the hippocampus of a rat model of Alzheimer＇s disease.

A Decreased Expression and Functionality of Muscarinic Cholinergic Receptor in Acute Chagas Myocarditis

Background: Chagas disease is still a public health problem because of the remaining high prevalence, the expansion of the disease into developed countries and the re-emergences by oral transmission outbreaks. Chagas cardiomyopathy evolves as a consequence of an autonomic un-balance where the parasympathetic tone is undermined. Objective: To determine the functionality and expression of muscarinic cholinergic receptors in acute Chagas disease. Methodology: 62 male, 3-week-old Sprague Dawley rats were assayed;32 were infected with Trypanosoma cruzi trypo-mastigotes and 30 were healthy controls. Electrocardiographic studies were conducted in the absence or presence of direct muscarinic (oxotremorine and McN-A-343) or indirect agonists (phenylephrine) or antagonist (pirenzepine). Muscarinic M1 and M2 receptor expression was determined by radioligand [3H]-QNB binding assay and immunoblot. Results: Chagasic acute myocarditis was sustained by electrocardiographic signs and histopathological findings. Bradycardia induced by oxotremorine was significantly higher in healthy rats (HR) and the differences were enhanced by CsCl. In the absence of the agonist, CsCl induced a greater bradycardia in chagasic rats (ChR). In HR McN-A-343 induced tachycardia, however it induces bradycardia in the presence of a acetylcholinesterase inhibitor (neostigmine);no effects were observed in ChR. Pirenzepine induced a higher tachycardia in HR. Phenylephrine in the presence of pirenzepine induced a similar bradycardia in both groups, but recovery was faster in ChR. Muscarinic M1 and M2 receptor density was higher in HR. Conclusion: Muscarinic receptor expression and functionality are decreased in the acute Chagas disease that could impact the evolution and prognosis of the disease.

Olfactory receptors in neural regeneration in the central nervous system

Olfactory receptors are crucial for detecting odors and play a vital role in our sense of smell,influencing behaviors from food choices to emotional memories.These receptors also contribute to our perception of flavor and have potential applications in medical diagnostics and environmental monitoring.The ability of the olfactory system to regenerate its sensory neurons provides a unique model to study neural regeneration,a phenomenon largely absent in the central nervous system.Insights gained from how olfactory neurons continuously replace themselves and reestablish functional connections can provide strategies to promote similar regenerative processes in the central nervous system,where damage often results in permanent deficits.Understanding the molecular and cellular mechanisms underpinning olfactory neuron regeneration could pave the way for developing therapeutic approaches to treat spinal co rd injuries and neurodegenerative diseases like Alzheimer's disease.Olfa ctory receptors are found in almost any cell of eve ry orga n/tissue of the mammalian body.This ectopic expression provides insights into the chemical structures that can activate olfactory receptors.In addition to odors,olfactory receptors in ectopic expression may respond to endogenous compounds and molecules produced by mucosal colonizing microbiota.The analysis of the function of olfactory receptors in ectopic expression provides valuable information on the signaling pathway engaged upon receptor activation and the receptor's role in proliferation and cell differentiation mechanisms.This review explo res the ectopic expression of olfa ctory receptors and the role they may play in neural regeneration within the central nervous system,with particular attention to compounds that can activate these receptors to initiate regenerative processes.Evidence suggests that olfactory receptors could serve as potential therapeutic targets for enhancing neural repair and recovery following central nervous system injuries.

C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 pathway as a therapeutic target and regulatory mechanism for spinal cord injury

Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis exhibits significant differences before and after injury.Recent studies have revealed that the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis is closely associated with secondary inflammatory responses and the recruitment of immune cells following spinal cord injury,suggesting that this axis is a novel target and regulatory control point for treatment.This review comprehensively examines the therapeutic strategies targeting the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis,along with the regenerative and repair mechanisms linking the axis to spinal cord injury.Additionally,we summarize the upstream and downstream inflammatory signaling pathways associated with spinal cord injury and the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review primarily elaborates on therapeutic strategies that target the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the latest progress of research on antagonistic drugs,along with the approaches used to exploit new therapeutic targets within the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the development of targeted drugs.Nevertheless,there are presently no clinical studies relating to spinal cord injury that are focusing on the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review aims to provide new ideas and therapeutic strategies for the future treatment of spinal cord injury.

Melanocortin 3,5 receptors immunohistochemical expression in colonic mucosa of inflammatory bowel disease patients:A matter of disease activity?

BACKGROUND Melanocortin 3 and 5 receptors(i.e.,MC3R and MC5R)belong to the melanocortin family.However,data regarding their role in inflammatory bowel diseases(IBD)are currently unavailable.AIM This study aims to ascertain their expression profiles in the colonic mucosa of Crohn’s disease(CD)and ulcerative colitis(UC),aligning them with IBD disease endoscopic and histologic activity.METHODS Colonic mucosal biopsies from CD/UC patients were sampled,and immunohisto-chemical analyses were conducted to evaluate the expression of MC3R and MC5R.Colonic sampling was performed on both traits with endoscopic scores(Mayo endoscopic score and CD endoscopic index of severity)consistent with inflamed mucosa and not consistent with disease activity(i.e.,normal appearing mucosa).RESULTS In both CD and UC inflamed mucosa,MC3R(CD:+7.7 fold vs normal mucosa,P<0.01;UC:+12 fold vs normal mucosa,P<0.01)and MC5R(CD:+5.5 fold vs normal mucosa,P<0.01;UC:+8.1 fold vs normal mucosa,P<0.01)were significantly more expressed compared to normal mucosa.CONCLUSION MC3R and MC5R are expressed in the colon of IBD patients.Furthermore,expression may differ according to disease endoscopic activity,with a higher degree of expression in the traits affected by disease activity in both CD and UC,suggesting a potential use of these receptors in IBD pharmacology.

Non-neuronal muscarinic receptor activation prevents apoptosis of endothelial cells induced by homocysteine

Objective Endothelial apoptosis plays an important role in the initiation of atherosclerosis. It would be useful to clarify whether activation of non-neuronal muscarinic receptor(NNMR) could prevent endothelial apoptosis and atherosclerosis. We investigated the effects of NNMR activation on regulating rat aortic endothelial cells(RAECs) apoptosis induced by homocysteine, an independent risk factor of atherosclerosis, and further studied its molecular mechanism. Methods RAECs were incubated using homocysteine at the concentration of 2.7 mmol/L for 36 h. RAECs were also pre-treated with carbachol or arecoline to examine their effects. RT-PCR was used to assess changes in the gene expression related to cell apoptosis. Results Incubation of RAECs with homocysteine at the concentration of 2.7 mmol/L resulted in morphologic changes, such as cellular shrinkage, membrane blebbing, chromatin condensation and margination. These could be attenuated by pretreatment with carbachol and arecoline at the concentration of 10 μmol/L for 12 h. Homocysteine induced apoptosis in RAECs and the molecular mechanisms were associated with the regulation of fas, fas-L and caspase-8 in the death receptor pathway, bcl-2, bcl-xL and bax in the mitochondrial pathway, caspase-12 in the endoplasmic reticulum pathway and caspase-3, caspase-6 and p53 as downstream effectors. Carbachol and arecoline attenuated the effects of homocysteine on genes in the death receptor pathway, in the mitochondrial pathway and in the downstream pathway. Atropine could reverse all of the effects of arecoline. Conclusion Activation of NNMR by carbacol and arecoline inhibits homocysteine-induced endothelial cell apoptosis mainly through regulation of death receptor pathway, mitochondrial pathway and downstream effectors.