Alpha7 nicotinic acetylcholine receptor activation attenuated intestine-derived acute lung injury

Aronia Melanocarpa Elliot Anthocyanins Inhibits Alcoholic Liver Disease by Activation of α7nAChR

The study wanted to explore the preventative effects of Aornia melanocarpa Elliot anthocyanins (AMA) to Alcoholic liver disease (ALD) by bioinformatics prediction and experimental verification. We founded 419 differentially expressed genes (DEGs) in GSE28619 related to ALD from GEO database, COL1A1 was selected by the core gene module construction and molecular docking. Mice were treated by intragastric administration of gradient 50% ethanol, AMA alleviated liver injury by ALD and ameliorated the model's body weight, lessened the liver inflammation according to histopathological evaluation, increased serum liver biochemical index (AST, ALT, TC, TG and LDL-C) and decreased HDL-C, reversed the expression of enzymes (ALDH and GSH-PX), decreased cytokines expression (Ki67, TNF-α and IL-6), reversed the expression of α7nAChR and collagen I, downregulated the PI3K-Akt pathway and Keap1/HO-1 pathway (p-PI3K, PI3K, p-Akt, Akt, Keap1, Nrf2, HO-1,GSK-3β and Bcl-2), indicated that α7nAChR and collagen I may be the AMA action targets.

TNF-α Induces Neutrophil Apoptosis Delay and Promotes Intestinal Ischemia-Reperfusion-Induced Lung Injury through Activating JNK/FoxO3a Pathway

Background

Intestinal ischemia is a common clinical critical illness. Intestinal ischemia-reperfusion (IIR) leads to acute lung injury (ALI), but the causative factors of ALI are unknown. The aim of this study was to reveal the causative factors and mechanisms of IIR-induced lung injury.

Methods

A mouse model of IIR was developed using C57BL/6 mice, followed by detection of lung injury status and plasma levels of inflammatory factors in sham-operated mice and model mice. Some model mice were treated with a tumor necrosis factor-α (TNF-α) inhibitor lenalidomide (10 mg/kg), followed by observation of lung injury status through hematoxylin and eosin staining and detection of neutrophil infiltration levels through naphthol esterase and Ly6G immunohistochemical staining. Additionally, peripheral blood polymorphonuclear neutrophils (PMNs) were cultured in vitro and then stimulated by TNF-α to mimic in vivo inflammatory stimuli; this TNF-α stimulation was also performed on PMNs after knockdown of FoxO3a or treatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125. PMN apoptosis after stimulation was detected using flow cytometry. Finally, the role of PMN apoptosis in IIR-induced lung injury was evaluated in vivo by detecting the ALI status in the model mice administered with ABT-199, a Bcl-2 inhibitor.

Results

IIR led to pulmonary histopathological injury and increased lung water content, which were accompanied by increased plasma levels of inflammatory factors, with the TNF-α plasma level showing the most pronounced increase. Inhibition of TNF-α led to effective reduction of lung tissue injury, especially that of the damaging infiltration of PMNs in the lung. In vitro knockdown of FoxO3a or inhibition of JNK activity could inhibit TNF-α-induced PMN apoptosis. Further in vivo experiments revealed that ABT-199 effectively alleviated lung injury and decreased inflammation levels by promoting PMN apoptosis during IIR-induced lung injury.

Conclusion

TNF-α activates the JNK/FoxO3a pathway to induce a delay in PMN apoptosis, which promotes IIR-induced lung injury.

Cellular Signal Transduction Pathways Involved in Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (II/R) injury is a common type of tissue and organ injury, secondary to intestinal and mesenteric vascular diseases. II/R is characterized by a high incidence rate and mortality. In the II/R process, intestinal barrier function is impaired and bacterial translocation leads to excessive reactive oxygen species, inflammatory cytokine release, and even apoptosis. A large number of inflammatory mediators and oxidative factors are released into the circulation, leading to severe systemic inflammation and multiple organ failure of the lung, liver, and kidney. Acute lung injury (ALI) is the most common complication, which gradually develops into acute respiratory distress syndrome and is the main cause of its high mortality. This review summarizes the signal transduction pathways and key molecules in the pathophysiological process of ALI induced by II/R injury and provides a new therapeutic basis for further exploration of the molecular mechanisms of ALI induced by II/R injury. In particular, this article will focus on the biomarkers involved in II/R-induced ALI.

Anti-inflammatory effects of α7-nicotinic ACh receptors are exerted through interactions with adenylyl cyclase-6

BACKGROUND AND PURPOSE

Nicotinic ACh receptors containing the α7 sub-unit (α7-nAChRs) suppress inflammation through a wide range of pathways in immune cells. These receptors are thus potentially involved in a number of inflammatory diseases. However, the detailed mechanisms underlying the anti-inflammatory effects of α7-nAChRs remain to be described.

EXPERIMENTAL APPROACH

Anti-inflammatory effects of α7-nAChR agonists were assessed in both murine macrophages (RAW 264.7) and bone marrow-derived macrophages (BMDM), stimulated with LPS, using immunoblotting, RT-PCR and luciferase reporter assays. The role of adenylyl cyclase-6 in the degradation of Toll-like receptor 4 (TLR4) following endocytosis, was explored via overexpression and knockdown. A mouse model of chronic obstructive pulmonary disease (COPD) induced by porcine pancreatic elastase was used to confirm key findings.

RESULTS

Anti-inflammatory effects of α7-nAChRs were largely dependent on adenylyl cyclase-6 activation, as knockdown of adenylyl cyclase-6 considerably reduced the effects of α7-nAChR agonists while adenylyl cyclase-6 overexpression promoted them. We found that α7-nAChRs and adenylyl cyclase-6 are co-localized in lipid rafts of macrophages and directly interact. Activation of adenylyl cyclase-6 led to increased degradation of TLR4. Administration of the α7-nAChR agonist PNU-282987 attenuated pathological and inflammatory end points in a mouse model of COPD.

CONCLUSION AND IMPLICATIONS

The α7-nAChRs inhibit inflammation through activating adenylyl cyclase-6 and promoting degradation of TLR4. The use of α7-nAChR agonists may represent a novel therapeutic approach for treating COPD and possibly other inflammatory diseases.

Activation of alpha7 nicotinic acetylcholine receptor protects bovine endometrial tissue against LPS-induced inflammatory injury via JAK2/STAT3 pathway and COX-2 derived prostaglandin E2

Bovine endometritis is one of the major postpartum diseases associated with infertility and subfertility, decreasing the benefit of dairy industry. It is important to develop alternate therapies for endometritis in the context of drug residues in the milk and hormone disorder in the estrous cycle. α7 nicotine acetylcholine receptor has been identified as the core of 'cholinergic anti-inflammatory pathway (CAP)', which is a potential drug target to inflammatory diseases. However, there has been still no study on its anti-inflammatory effects and mechanism on lipopolysaccharide (LPS)-induced bovine endometritis. This study aimed to demonstrate the underlying anti-inflammatory effects and mechanism of α7-nACh receptor on LPS-induced inflammation in bovine endometrial tissues cultured in vitro. The results suggested that activation of α7-nACh receptor significantly suppressed the mRNA expression levels of interleukin 1β (IL-1β), IL-6, IL-8, and tumor necrosis factor alpha (TNF-α) in bovine endometrial tissues. Western blot and enzyme-linked immunosorbent assay (ELISA) detection results showed that activation of α7-nACh receptor inhibited LPS-induced phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). Moreover, α7-nACh receptor agonist decreased the expression of cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase-1(mPGES-1), as well as prostaglandin E₂ (PGE₂) secretion. Interestingly, in COX-2 inhibition experiment, activation of α7-nACh receptor increased COX-2 expression and PGE₂ production, compared with COX-2 inhibitor treatment. In conclusion, activation of the cholinergic system through α7-nACh receptor agonist has suppressed inflammation of bovine endometrial tissues via JAK2/STAT3 pathway and potential COX-2-derived PGE₂.

Lung Edema and Mortality Induced by Intestinal Ischemia and Reperfusion Is Regulated by VAChT Levels in Female Mice

Acute lung injury induced by intestinal ischemia/reperfusion (I/R) is a relevant clinical condition. Acetylcholine (ACh) and the α7 nicotinic ACh receptor (nAChRα-7) are involved in the control of inflammation. Mice with reduced levels of the vesicular ACh transporter (VAChT), a protein responsible for controlling ACh release, were used to test the involvement of cholinergic signaling in lung inflammation due to intestinal I/R. Female mice with reduced levels of VAChT (VAChT-KD^HOM) or wild-type littermate controls (WT) were submitted to intestinal I/R followed by 2 h of reperfusion. Mortality, vascular permeability, and recruitment of inflammatory cells into the lung were investigated. Parts of mice were submitted to ovariectomy (OVx) to study the effect of sex hormones or treated with PNU-282,987 (nAChRα-7 agonist). A total of 43.4% of VAChT-KD^HOM-I/R mice died in the reperfusion period compared to 5.2% of WT I/R mice. The I/R increased lung inflammation in both genotypes. In VAChT-KD^HOM mice, I/R increased vascular permeability and decreased the release of cytokines in the lung compared to WT I/R mice. Ovariectomy reduced lung inflammation and permeability compared to non-OVx, but it did not avoid mortality in VAChT-KD^HOM-I/R mice. PNU treatment reduced lung permeability, increased the release of proinflammatory cytokines and the myeloperoxidase activity in the lungs, and prevented the increased mortality observed in VAChT-KD^HOM mice. Cholinergic signaling is an important component of the lung protector response against intestinal I/R injury. Decreased cholinergic signaling seems to increase pulmonary edema and dysfunctional cytokine release that increased mortality, which can be prevented by increasing activation of nAChRα-7.

Effects of Connexin 32-Mediated Lung Inflammation Resolution During Liver Ischemia Reperfusion

BACKGROUND

Hepatic ischemia reperfusion (HIR) leads to a lung inflammatory response and subsequent pulmonary barrier dysfunction. The gap junction communication protein connexin 32 (Cx32), which is widely expressed in the lungs, participates in intercellular signaling. This study determined whether the communication protein Cx32 could affect pulmonary inflammation caused by HIR.

METHODS

Mice were randomly allocated into four groups (n = 8/group): (i) Cx32+/+ sham group; (ii) Cx32+/+ HIR model group; (iii) Cx32-/- sham group; and (iv) Cx32-/- HIR model group. Twenty-four hours after surgery, lung tissues were collected for bright field microscopy, western blot (Cx32, JAK2, p-JAK2, STAT3, p-STAT3), and immunofluorescence (ZO-1, 8-OHDG) analyses. The collected bronchoalveolar fluid was tested for levels of interleukin-6 (IL-6), matrix metalloproteinase 12 (MMP-12), and antitrypsin (α1-AT). Lung mmu-miR-26a/b expression was detected using a PCR assay.

RESULTS

Increased expression of Cx32 mRNA and protein was noted in the lungs after HIR. Cx32 deletion significantly aggravated pulmonary function from acute lung injury induced by HIR. In addition, Cx32 deletion decreased the protein level of ZO-1 (pulmonary function) and increased the level of the oxidative stress marker 8-OHDG in the lungs. Moreover, in the Cx32-/- HIR model group, the levels of IL-6 and MMP-12 in bronchoalveolar lavage fluid were significantly increased leading to activation of the JAK2/STAT3 pathway, and decreased α1-AT levels. Furthermore, we found mmu-miR-26a/b was significantly downregulated in the Cx32-/- HIR model group.

CONCLUSION

HIR leads to acute lung inflammatory injury. Cx32 deletion aggravates hepatic-derived lung inflammation, partly through blocking the transferring of mmu-miR-26a/b and leading to IL-6-related JAK2/STAT3 pathway activation.

Dexmedetomidine-mediated protection against septic liver injury depends on TLR4/MyD88/NF-κB signaling downregulation partly via cholinergic anti-inflammatory mechanisms

BACKGROUND

Uncontrolled inflammatory responses exacerbate the pathogenesis of septic acute liver injury (ALI), posing a lethal threat to the host. Dexmedetomidine (DEX) has been reported to possess protective properties in inflammatory conditions. This study aimed to investigate whether DEX pretreatment exhibits hepatoprotection against ALI induced by lipopolysaccharide (LPS) in rats and determine its possible molecular mechanism.

METHODS

Septic ALI was induced by intravenous injection of LPS. The rats received DEX intraperitoneally 30 min before LPS administration. α-Bungarotoxin (α-BGT), a specific α7 nicotinic acetylcholine receptor (α7nAChR) antagonist, was administered intraperitoneally 1 h before LPS exposure. The role of the vagus nerve was verified by performing unilateral cervical vagotomy or sham surgery before sepsis.

RESULTS

The expression of α7nAChR, toll-like receptor 4 (TLR4), high mobility group box 1 (HMGB1), and cleaved caspase-3 increased, peaking 24 h during sepsis. DEX enhanced α7nAChR activation and reduced TLR4 expression upon challenge with LPS. DEX significantly prevented LPS-induced ALI, which was associated with increased survival, the mitigation of pathological changes, the attenuation of inflammatory cytokine expression and apoptosis, and the downregulation of TLR4/MyD88/NF-κB pathway. Moreover, the hepatoprotective effect of DEX was abolished by α-BGT. Further investigation established that vagotomy, compared to sham surgery, triggered more severe pathogenic manifestations and higher proinflammatory cytokine levels. The inhibitory effects of DEX were shown in sham-operated rats but not in vagotomized rats.

CONCLUSIONS

Our data highlight the pivotal function of α7nAChR and intact vagus nerves in protecting against LPS-induced ALI through inhibiting the TLR4/MyD88/NF-κB signaling pathway upon pretreatment with DEX.

Protective effects of PNU‑282987 on sepsis‑induced acute lung injury in mice

The cholinergic anti‑inflammatory pathway is considered an attractive approach for the alleviation of inflammatory diseases. Sepsis is characterized by systemic inflammation and widespread organ injury, especially that in the lung. In the present study, we explored the effects of an α7nAChR agonist, PNU‑282987, on sepsis‑induced lung injury and investigated the mechanisms of PNU‑282987 in response to lipopolysaccharide (LPS) stimulation in peritoneal macrophages. Sepsis was induced in C57BL/6 mice via cecal ligation puncture (CLP). Fifty mice were randomly divided into five groups: The sham group treated with vehicle, the sham group treated with PNU‑282987, the CLP group treated with vehicle, and the CLP group treated with PNU‑282987 (1 mg/kg) 1 h before or 2 h after surgery. All mice were sacrificed at 12 or 24 h after CLP. Both pre‑ and post‑CLP treatment with PNU‑282987 significantly attenuated sepsis‑induced lung injury and the release of IL‑6 in the bronchoalveolar lavage fluid (BALF). Pre‑treatment with PNU‑282987 also inhibited sepsis‑increased TNF‑α and IL‑6 production, while post‑CLP treatment only inhibited IL‑6 production in the lung tissue. Neither pre‑ nor post‑CLP treatment with PNU‑282987 affected IL‑6 release in the serum. Furthermore, pretreatment with PNU‑282987 resulted in reductions in TNF‑α and IL‑6 release in a dose‑ and time‑dependent manner and decreased the phosphorylation levels of p38, JNK and ERK under LPS conditions in peritoneal macrophages. Our results demonstrate that activation of α7nAChR alleviates sepsis‑induced lung injury; this effect is associated with the suppression of inflammatory responses via the MAPK pathway, suggesting that α7nAChR is a potential therapeutic target for the treatment of sepsis.

Gene fingerprint model for literature based detection of the associations among complex diseases: a case study of COPD

BACKGROUND

Disease comorbidity is very common and has significant impact on disease treatment. Revealing the associations among diseases may help to understand the mechanisms of diseases, improve the prevention and treatment of diseases, and support the discovery of new drugs or new uses of existing drugs.

METHODS

In this paper, we introduced a mathematical model to represent gene related diseases with a series of associated genes based on the overrepresentation of genes and diseases in PubMed literature. We also illustrated an efficient way to reveal the implicit connections between COPD and other diseases based on this model.

RESULTS

We applied this approach to analyze the relationships between Chronic Obstructive Pulmonary Disease (COPD) and other diseases under the Lung diseases branch in the Medical subject heading index system and detected 4 novel diseases relevant to COPD. As judged by domain experts, the F score of our approach is up to 77.6%.

CONCLUSIONS

The results demonstrate the effectiveness of the gene fingerprint model for diseases on the basis of medical literature.

The Cholinergic Pathways in Inflammation: A Potential Pharmacotherapeutic Target for COPD

In COPD, the activity of the cholinergic system is increased, which is one of the reasons for the airflow limitation caused by the contraction of airway smooth muscles. Therefore, blocking the contractive actions with anticholinergics is a useful therapeutic intervention to reduce the airflow limitation. In addition to the effects of bronchoconstriction and mucus secretion, accumulating evidence from animal models of COPD suggest acetylcholine has a role in inflammation. Experiments using muscarinic M₃-receptor deficient mice or M₃ selective antagonists revealed that M₃-receptors on parenchymal cells, but not on hematopoietic cells, are involved in the pro-inflammatory effect of acetylcholine. Recently, combinations of long-acting β2 adrenergic agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) have become available for COPD treatment. These dual long-acting bronchodilators may have synergistic anti-inflammatory effects because stimulation of β2 adrenergic receptors induces inhibitory effects in inflammatory cells via a different signaling pathway from that by antagonizing M₃-receptor, though these anti-inflammatory effects have not been clearly demonstrated in COPD patients. In contrast to the pro-inflammatory effects by ACh via muscarinic receptors, it has been demonstrated that the cholinergic anti-inflammatory pathway, which involves the parasympathetic nervous systems, regulates excessive inflammatory responses to protect organs during tissue injury and infection. Stimulation of acetylcholine via the α7 nicotinic acetylcholine receptor (α7nAChR) exerts inhibitory effects on leukocytes including macrophages and type 2 innate lymphoid cells. Although it remains unclear whether the inhibitory effects of acetylcholine via α7nAChR in inflammatory cells can regulate inflammation in COPD, neuroimmune interactions including the cholinergic anti-inflammatory pathway might serve as potential therapeutic targets.

3-Dehydroandrographolide protects against lipopolysaccharide-induced inflammation through the cholinergic anti-inflammatory pathway

Acute lung injury (ALI) is a deadly disease without effective chemotherapy, so far. Traditional Chinese medicine andrographis herba is frequently used in the treatment of respiratory diseases. In searching for natural anti-ALI components from andrographis herba, the activities of 3-dehydroandrographolide (3-DA), a new natural andrographolide product from andrographis herba were evaluated. In this study, murine macrophage RAW 264.7 cells and BALB/c mice were treated with LPS (lipopolysaccharide, 100 ng/ml in vitro; 3 mg/kg, intratracheal) to establish inflammation models. 3-DA attenuated the release of pro-inflammatory cytokines IL-6 and TNF-α, inhibited the degradation and phosphorylation of IκBα, and suppressed the nuclear translocation of NF-κB p65 as well as the phosphorylation of Akt at Ser473 in LPS-stimulated RAW 264.7 macrophage cells. Furthermore, 3-DA increased α7nAchR expression level and bound with α7nAchR. More importantly, the anti-inflammatory effects of 3-DA were counteracted in the presence of α7nAchR siRNA or methyllycaconitine (MLA, a α7nAchR specific inhibitor), suggesting that α7nAchR is a potential target in the anti-inflammatory effects of 3-DA. Besides, 3-DA significantly inhibited inflammation in LPS-induced ALI mice, which was associated with the decrease of lung water content and inflammatory cytokines, the inhibition of neutrophil and macrophage infiltration, and activation of the NF-κB/Akt signaling pathway. Moreover, these protective effects were attenuated by the treatment of MLA. Taken together, 3-DA alleviates LPS-induced inflammation via the cholinergic anti-inflammatory pathway in vitro and in vivo. These findings provide a rationale for the role of the cholinergic anti-inflammatory pathway in inflammation and the promising clinical application of 3-DA to treat ALI.

Revisiting the Cardioprotective Effects of Acetylcholine Receptor Activation against Myocardial Ischemia/Reperfusion Injury

Acute myocardial infarction (AMI) is the most common cause of acute myocardial injury and its most clinically significant form. The most effective treatment for AMI is to restore an adequate coronary blood flow to the ischemic myocardium as quickly as possible. However, reperfusion of an ischemic region can induce cardiomyocyte death, a phenomenon termed “myocardial ischemia/reperfusion (I/R) injury”. Disruption of cardiac parasympathetic (vagal) activity is a common hallmark of a variety of cardiovascular diseases including AMI. Experimental studies have shown that increased vagal activity exerts cardioprotective effects against myocardial I/R injury. In addition, acetylcholine (ACh), the principle cardiac vagal neurotransmitter, has been shown to replicate the cardioprotective effects of cardiac ischemic conditioning. Moreover, studies have shown that cardiomyocytes can synthesize and secrete ACh, which gives further evidence concerning the importance of the non-neuronal cholinergic signaling cascades. This suggests that the activation of ACh receptors is involved in cardioprotection against myocardial I/R injury. There are two types of ACh receptors (AChRs), namely muscarinic and nicotinic receptors (mAChRs and nAChRs, respectively). However, the effects of AChRs activation in cardioprotection during myocardial I/R are still not fully understood. In this review, we summarize the evidence suggesting the association between AChRs activation with both electrical and pharmacological interventions and the cardioprotection during myocardial I/R, as well as outline potential mechanisms underlying these cardioprotective effects.

Transduced PEP-1-Heme Oxygenase-1 Fusion Protein Attenuates Lung Injury in Septic Shock Rats

Oxidative stress and inflammation have been identified to play a vital role in the pathogenesis of lung injury induced by septic shock. Heme oxygenase-1 (HO-1), an effective antioxidant and anti-inflammatory and antiapoptotic substance, has been used for the treatment of heart, lung, and liver diseases. Thus, we postulated that administration of exogenous HO-1 protein transduced by cell-penetrating peptide PEP-1 has a protective role against septic shock-induced lung injury. Septic shock produced by cecal ligation and puncture caused severe lung damage, manifested in the increase in the lung wet/dry ratio, oxidative stress, inflammation, and apoptosis. However, these changes were reversed by treatment with the PEP-1-HO-1 fusion protein, whereas lung injury in septic shock rats was alleviated. Furthermore, the septic shock upregulated the expression of Toll-like receptor 4 (TLR4) and transcription factor NF-κB, accompanied by the increase of lung injury. Administration of PEP-1-HO-1 fusion protein reversed septic shock-induced lung injury by downregulating the expression of TLR4 and NF-κB. Our study indicates that treatment with HO-1 protein transduced by PEP-1 confers protection against septic shock-induced lung injury by its antioxidant, anti-inflammatory, and antiapoptotic effects.

Altered Neuroendocrine Immune Responses, a Two-Sword Weapon against Traumatic Inflammation

During the occurrence and development of injury (trauma, hemorrhagic shock, ischemia and hypoxia), the neuroendocrine and immune system act as a prominent navigation leader and possess an inter-system crosstalk between the reciprocal information dissemination. The fundamental reason that neuroendocrinology and immunology could mix each other and permeate toward the field of traumatology is owing to their same biological languages or chemical information molecules (hormones, neurotransmitters, neuropeptides, cytokines and their corresponding receptors) shared by the neuroendocrine and immune systems. The immune system is not only modulated by the neuroendocrine system, but also can modulate the biological functions of the neuroendocrine system. The interactive linkage of these three systems precipitates the complicated space-time patterns for the courses of traumatic inflammation. Recently, compelling evidence indicates that the network linkage pattern that initiating agents of neuroendocrine responses, regulatory elements of immune cells and effecter targets for immune regulatory molecules arouse the resistance mechanism disorders, which supplies the beneficial enlightenment for the diagnosis and therapy of traumatic complications from the view of translational medicine. Here we review the alternative protective and detrimental roles as well as possible mechanisms of the neuroendocrine immune responses in traumatic inflammation.

α7 Nicotinic Agonist AR-R17779 Protects Mice against 2,4,6-Trinitrobenzene Sulfonic Acid-Induced Colitis in a Spleen-Dependent Way

The existence of a cholinergic anti-inflammatory pathway negatively modulating the inflammatory and immune responses in various clinical conditions and experimental models has long been postulated. In particular, the protective involvement of the vagus nerve and of nicotinic Ach receptors (nAChRs) has been proposed in intestinal inflammation and repeatedly investigated in DSS- and TNBS-induced colitis. However, the role of α7 nAChRs stimulation is still controversial and the potential contribution of α4β2 nAChRs has never been explored in this experimental condition. Our aims were therefore to pharmacologically investigate the role played by both α7 and α4β2 nAChRs in the modulation of the local and systemic inflammatory responses activated in TNBS-induced colitis in mice and to assess the involvement of the spleen in nicotinic responses. To this end, TNBS-exposed mice were sub-acutely treated with various subcutaneous doses of highly selective agonists (AR-R17779 and TC-2403) and antagonists (methyllycaconitine and dihydro-β-erythroidine) of α7 and α4β2 nAChRs, respectively, or with sulfasalazine 50 mg/kg per os and clinical and inflammatory responses were evaluated by means of biochemical, histological and flow cytometry assays. α4β2 ligands evoked weak and contradictory effects, while α7 nAChR agonist AR-R17779 emerged as the most beneficial treatment, able to attenuate several local markers of colitis severity and to revert the rise in splenic T-cells and in colonic inflammatory cytokines levels induced by haptenization. After splenectomy, AR-R17779 lost its protective effects, demonstrating for the first time that, in TNBS-model of experimental colitis, the anti-inflammatory effect of exogenous α7 nAChR stimulation is strictly spleen-dependent. Our findings showed that the selective α7 nAChRs agonist AR-R17779 exerted beneficial effects in a model of intestinal inflammation characterized by activation of the adaptive immune system and that the spleen is essential to mediate this cholinergic protection.

Recombinant Newcastle disease virus rL-RVG enhances the apoptosis and inhibits the migration of A549 lung adenocarcinoma cells via regulating alpha 7 nicotinic acetylcholine receptors in vitro

BACKGROUND

The aim of this study were to investigate the possible pro-apoptotic mechanisms of the recombinant Newcastle disease virus (NDV) strain rL-RVG, which expresses the rabies virus glycoprotein, in A549 lung adenocarcinoma cells via the regulation of alpha 7 nicotinic acetylcholine receptors (α7 nAChRs) and to analyze the relationships between α7 nAChR expression in lung cancer and the clinical pathological features.

METHODS

α7 nAChR expression in A549, LΑ795, and small-cell lung carcinoma (SCLC) cells, among others, was detected using reverse transcription polymerase chain reaction (RT-PCR). The optimal α7 nAChR antagonist and agonist concentrations for affecting A549 lung adenocarcinoma cells were detected using MTT assays. The α7 nAChR expression in A549 cells after various treatments was assessed by Western blot, immunofluorescence and RT-PCR analyses. Apoptosis in the various groups was also monitored by Western blot and TUNEL assays, followed by the detection of cell migration via transwell and scratch tests. Furthermore, α7 nAChR expression was examined by immunohistochemistry in lung cancer tissue samples from 130 patients and 40 pericancerous tissue samples, and the apoptotis in lung adenocarcinoma tissue was detected by Tunel assay, Then, the expression levels and clinicopathological characteristics were analyzed.

RESULTS

Of the A549, LΑ795, SCLC and U251 cell lines, the A549 cells exhibited the highest α7 nAChR expression. The cells infected with rL-RVG exhibited high RVG gene and protein expression. The rL-RVG group exhibited weaker α7 nAChR expression compared with the methyllycaconitine citrate hydrate (MLA, an α7 nAChR antagonist) and NDV groups. At the same time, the MLA and rL-RVG treatments significantly inhibited proliferation and migration and promoted apoptosis in the lung cancer cells (P < 0.05). The expression of α7 nAChR was upregulated in lung cancer tissue compared with pericancerous tissue (P = 0.000) and was significantly related to smoking, clinical tumor-node-metastases stage, and histological differentiation (P < 0.05). The AI in lung adenocarcinoma tissue in high-medium differentiation group was lower than that in low differentiation group (p < 0.01).

CONCLUSIONS

An antagonist of α7 nAChR may be used as a molecular target for lung adenocarcinoma therapy. Recombinant NDV rL-RVG enhances the apoptosis and inhibits the migration of A549 lung adenocarcinoma cells by regulating α7 nAChR signaling pathways.