[Immunological mechanism of Ermiao Powder improving inflammation in rats with collagen-induced arthritis through α7nAChR-JAK2/STAT3 pathway].

This study investigated the immunological mechanisms of Ermiao powder in the treatment of rheumatoid arthritis rats through the alpha 7 nicotinic acetylcholine receptor(α7nAChR)-Janus kinases 2(JAK2)/signal transducer and activator of transcription 3(STAT3) signaling pathway. A total of 56 female Wistar rats were randomly divided into the normal group(HG, n=8), collagen-induced arthritis(CIA) model group(CM, n=8), vagotomy group(VA, n=8), sham group(SH, n=8), Ermiao Powder treatment model group(EM, n=8), Ermiao Powder treatment for vagotomy group(EV, n=8) and Ermiao Powder treatment for sham group(ES, n=8). Following the establishment of CIA models in all groups except the HG group, the rats underwent unilateral vagotomy and sham operation(only the vagus nerve was separated). Drug treatment was started 7 days after surgery and continued for 35 days. The body weight and joints of rats were recorded, the pathological changes of the spleen of rats were observed, the contents of interleukin-6(IL-6), interleukin-1ß(IL-1ß) and tumor necrosis factor-α(TNF-α) in serum were detected by enzyme-linked immunosorbent assay(ELISA), and the mRNA and protein expression of α7nAChR-JAK2/STAT3 pathway core genes in spleen were detected by qRT-PCR, Western blot and immunohistochemistry. RESULTS:: showed that CM group(compared with HG group) and VA group(compared with CM group and SH group) had significantly decreased body weight(P<0.05, P<0.01), increased arthritis score(P<0.05, P<0.01), swollen ankle joints with deformity, and increased and enlarged lymph nodes in the spleen. There were also notable increases in the serum levels of IL-6, IL-1ß and TNF-α(P<0.05, P<0.01), and in the mRNA expressions of JAK2 and STAT3 in the spleen(P<0.05, P<0.01). The protein levels of phosphorylated JAK2(p-JAK2)/JAK2 and phospho-STAT3(p-STAT3)/STAT3 were significantly increased(P<0.05, P<0.01), and the number of JAK2, p-JAK2, STAT3 and p-STAT3 cells increased(P<0.05, P<0.01). EM group(compared with CM group) and ES group(compared with SH group) exhibited significantly increased body weight(P<0.01), decreased arthritis scores(P<0.05, P<0.01), reduced swelling of ankle joint, and decreased number and volume of lymph nodes in the spleen. Furthermore, serum levels of IL-6, IL-1ß, and TNF-α decreased(P<0.05, P<0.01), the mRNA expression of JAK2 and STAT3 in spleen decreased(P<0.05, P<0.01), the protein levels of p-JAK2/JAK2 and p-STAT3/STAT3 decreased(P<0.05, P<0.01), and the number of JAK2, p-JAK2, STAT3 and p-STAT3 cells decreased(P<0.05, P<0.01), whereas the mRNA and protein expressions of α7nAChR were significantly increased(P<0.01). Compared with the VA group, there was no significant differences in weight gain and arthritis scores in the EV group. The number of lymph nodes in the spleen was not significantly reduced and the volume was still large, suggesting the inflammation was not significantly improved. The serum levels of IL-6, IL-1ß and TNF-α were not significantly different, and there were no significant differences in α7nAChR, JAK2, and STAT3 mRNA expression in the spleen. The protein expression levels of p-JAK2/JAK2 and α7nAChR in spleen were lower(P<0.05, P<0.01), while p-STAT3/STAT3 protein expression was not significantly different. Besides, the two groups had no significant difference in the number of JAK2, p-JAK2, STAT3, and p-STAT3 cells. The results suggested that unilateral vagotomy promoted the increase of phosphorylated JAK2 and STAT3 expressions and exacerbated inflammation. In contrast, Ermiao Powder alleviated the inflammation in rheumatoid arthritis rats by activating the α7nAChR-mediated JAK2/STAT3 pathway through the vagus nerve, suggesting that the α7nAchR-JAK2/STAT3 pathway may be a potential target for the treatment of rheumatoid arthritis.

Acetamiprid induces cardiotoxicity in rats by dysregulating α7 nAChR and its downstream targets: The ameliorative role of resveratrol.

Acetamiprid (ACP) is a novel neonicotinoid insecticide used for controlling insect pests. Resveratrol (RSV) is a natural polyphenol that possesses anti-oxidant, anti-inflammatory and anti-apoptotic actions. The current research explores the mechanism of ACP-induced cardiotoxicity and the alleviative effects of RSV. Male rats were allocated to four groups of ten each. Rats were treated daily for 90 days via oral route. Control rats received distilled water, ACP rats received 25 mg acetamiprid/kg, RSV rats received 20 mg resveratrol/kg and ACP + RSV rats received both ACP and RSV. ACP exposure increased serum creatine phosphokinase activity and cardiac troponin level. It also induced oxidative stress, as evidenced by the glutathione reduction, and malondialdehyde elevation, as well as the detrimental histopathological and immunohistochemical changes in the myocardium. Gene expression analysis revealed down-regulation in the mRNA expression of the survival-related genes α7 nAChR, Erk and Bcl-2, and up-regulation in the apoptosis-related genes Jnk, Bax and Caspase-3. Conversely, the concomitant administration of ACP with RSV alleviated most of the aforementioned toxic impacts. It can be concluded that ACP induces cardiotoxicity by dysregulating the mRNA expression of α7 nAChR and its downstream targets. Additionally, RSV is proved to be a promising ameliorative agent against ACP-induced cardiotoxicity.

Nicotine aggravates liver fibrosis via α7 nicotinic acetylcholine receptor expressed on activated hepatic stellate cells in mice.

BACKGROUND: Smoking is a risk factor for liver cirrhosis; however, the underlying mechanisms remain largely unexplored. The α7 nicotinic acetylcholine receptor (α7nAChR) has recently been detected in nonimmune cells possessing immunoregulatory functions. We aimed to verify whether nicotine promotes liver fibrosis via α7nAChR. METHODS: We used osmotic pumps to administer nicotine and carbon tetrachloride to induce liver fibrosis in wild-type and α7nAChR-deficient mice. The severity of fibrosis was evaluated using Masson trichrome staining, hydroxyproline assays, and real-time PCR for profibrotic genes. Furthermore, we evaluated the cell proliferative capacity and COL1A1 mRNA expression in human HSCs line LX-2 and primary rat HSCs treated with nicotine and an α7nAChR antagonist, methyllycaconitine citrate. RESULTS: Nicotine exacerbated carbon tetrachloride-induced liver fibrosis in mice (+42.4% in hydroxyproline assay). This effect of nicotine was abolished in α7nAChR-deficient mice, indicating nicotine promotes liver fibrosis via α7nAChR. To confirm the direct involvement of α7nAChRs in liver fibrosis, we investigated the effects of genetic suppression of α7nAChR expression on carbon tetrachloride-induced liver fibrosis without nicotine treatment. Profibrotic gene expression at 1.5 weeks was significantly suppressed in α7nAChR-deficient mice (-83.8% in Acta2, -80.6% in Col1a1, -66.8% in Tgfb1), and collagen content was decreased at 4 weeks (-22.3% in hydroxyproline assay). The in vitro analysis showed α7nAChR expression in activated but not in quiescent HSCs. Treatment of LX-2 cells with nicotine increased COL1A1 expression (+116%) and cell proliferation (+10.9%). These effects were attenuated by methyllycaconitine citrate, indicating the profibrotic effects of nicotine via α7nAChR. CONCLUSIONS: Nicotine aggravates liver fibrosis induced by other factors by activating α7nAChR on HSCs, thereby increasing their collagen-producing capacity. We suggest the profibrotic effect of nicotine is mediated through α7nAChRs.

CHRFAM7A diversifies human immune adaption through Ca2+ signalling and actin cytoskeleton reorganization.

BACKGROUND: Human restricted genes contribute to human specific traits in the immune system. CHRFAM7A, a uniquely human fusion gene, is a negative regulator of the α7 nicotinic acetylcholine receptor (α7 nAChR), the highest Ca2+ conductor of the ACh receptors implicated in innate immunity. Understanding the mechanism of how CHRFAM7A affects the immune system remains unexplored. METHODS: Two model systems are used, human induced pluripotent stem cells (iPSC) and human primary monocytes, to characterize α7 nAChR function, Ca2+ dynamics and decoders to elucidate the pathway from receptor to phenotype. FINDINGS: CHRFAM7A/α7 nAChR is identified as a hypomorphic receptor with mitigated Ca2+ influx and prolonged channel closed state. This shifts the Ca2+ reservoir from the extracellular space to the endoplasmic reticulum (ER) leading to Ca2+ dynamic changes. Ca2+ decoder small GTPase Rac1 is then activated, reorganizing the actin cytoskeleton. Observed actin mediated phenotypes include cellular adhesion, motility, phagocytosis and tissue mechanosensation. INTERPRETATION: CHRFAM7A introduces an additional, human specific, layer to Ca2+ regulation leading to an innate immune gain of function. Through the actin cytoskeleton it drives adaptation to the mechanical properties of the tissue environment leading to an ability to invade previously immune restricted niches. Human genetic diversity predicts profound translational significance as its understanding builds the foundation for successful treatments for infectious diseases, sepsis, and cancer metastasis. FUNDING: This work is supported in part by the Community Foundation for Greater Buffalo (Kinga Szigeti) and in part by NIH grant R01HL163168 (Yongho Bae).

Subtype-Selective Peptide and Protein Neurotoxic Inhibitors of Nicotinic Acetylcholine Receptors Enhance Proliferation of Patient-Derived Glioblastoma Cell Lines.

Glioblastoma multiforme (GBM) is the most aggressive type of brain cancer, with a poor prognosis. GBM cells, which develop in the environment of neural tissue, often exploit neurotransmitters and their receptors to promote their own growth and invasion. Nicotinic acetylcholine receptors (nAChRs), which play a crucial role in central nervous system signal transmission, are widely represented in the brain, and GBM cells express several subtypes of nAChRs that are suggested to transmit signals from neurons, promoting tumor invasion and growth. Analysis of published GBM transcriptomes revealed spatial heterogeneity in nAChR subtype expression, and functional nAChRs of α1*, α7, and α9 subtypes are demonstrated in our work on several patient-derived GBM microsphere cultures and on the U87MG GBM cell line using subtype-selective neurotoxins and fluorescent calcium mobilization assay. The U87MG cell line shows reactions to nicotinic agonists similar to those of GBM patient-derived culture. Selective α1*, α7, and α9 nAChR neurotoxins stimulated cell growth in the presence of nicotinic agonists. Several cultivating conditions with varying growth factor content have been proposed and tested. The use of selective neurotoxins confirmed that cell cultures obtained from patients are representative GBM models, but the use of media containing fetal bovine serum can lead to alterations in nAChR expression and functioning.

Cholinergic signaling via the α7 nicotinic acetylcholine receptor regulates the migration of monocyte-derived macrophages during acute inflammation.

BACKGROUND: The involvement of the autonomic nervous system in the regulation of inflammation is an emerging concept with significant potential for clinical applications. Recent studies demonstrate that stimulating the vagus nerve activates the cholinergic anti-inflammatory pathway that inhibits pro-inflammatory cytokines and controls inflammation. The α7 nicotinic acetylcholine receptor (α7nAChR) on macrophages plays a key role in mediating cholinergic anti-inflammatory effects through a downstream intracellular mechanism involving inhibition of NF-κB signaling, which results in suppression of pro-inflammatory cytokine production. However, the role of the α7nAChR in the regulation of other aspects of the immune response, including the recruitment of monocytes/macrophages to the site of inflammation remained poorly understood. RESULTS: We observed an increased mortality in α7nAChR-deficient mice (compared with wild-type controls) in mice with endotoxemia, which was paralleled with a significant reduction in the number of monocyte-derived macrophages in the lungs. Corroborating these results, fluorescently labeled α7nAChR-deficient monocytes adoptively transferred to WT mice showed significantly diminished recruitment to the inflamed tissue. α7nAChR deficiency did not affect monocyte 2D transmigration across an endothelial monolayer, but it significantly decreased the migration of macrophages in a 3D fibrin matrix. In vitro analysis of major adhesive receptors (L-selectin, ß1 and ß2 integrins) and chemokine receptors (CCR2 and CCR5) revealed reduced expression of integrin αM and αX on α7nAChR-deficient macrophages. Decreased expression of αMß2 was confirmed on fluorescently labeled, adoptively transferred α7nAChR-deficient macrophages in the lungs of endotoxemic mice, indicating a potential mechanism for α7nAChR-mediated migration. CONCLUSIONS: We demonstrate a novel role for the α7nAChR in mediating macrophage recruitment to inflamed tissue, which indicates an important new aspect of the cholinergic regulation of immune responses and inflammation.

The Prenatal Hypoxic Pathology Associated with Maternal Stress Predisposes to Dysregulated Expression of the chrna7 Gene and the Subsequent Development of Nicotine Addiction in Adult Offspring.

INTRODUCTION: Previous studies have shown that fetal hypoxia predisposes individuals to develop addictive disorders in adulthood. However, the specific impact of maternal stress, mediated through glucocorticoids and often coexisting with fetal hypoxia, is not yet fully comprehended. METHODS: To delineate the potential effects of these pathological factors, we designed models of prenatal severe hypoxia (PSH) in conjunction with maternal stress and prenatal intrauterine ischemia (PII). We assessed the suitability of these models for our research objectives by measuring HIF1α levels and evaluating the glucocorticoid neuroendocrine system. To ascertain nicotine dependence, we employed the conditioned place aversion test and the startle response test. To identify the key factor implicated in nicotine addiction associated with PSH, we employed techniques such as Western blot, immunohistochemistry, and correlational analysis between chrna7 and nr3c1 genes across different brain structures. RESULTS: In adult rats exposed to PSH and PII, we observed increased levels of HIF1α in the hippocampus (HPC). However, the PSH group alone exhibited reduced glucocorticoid receptor levels and disturbed circadian glucocorticoid rhythms. Additionally, they displayed signs of nicotine addiction in the conditioned place aversion and startle response tests. We also observed elevated levels of phosphorylated DARPP-32 protein in the nucleus accumbens (NAc) indicated compromised glutamatergic efferent signaling. Furthermore, there was reduced expression of α7 nAChR, which modulates glutamate release, in the medial prefrontal cortex (PFC) and HPC. Correlation analysis revealed strong associations between chrna7 and nr3c1 expression in both brain structures. CONCLUSION: Perturbations in the glucocorticoid neuroendocrine system and glucocorticoid-dependent gene expression of chrna7 associated with maternal stress response to hypoxia in prenatal period favor the development of nicotine addiction in adulthood.

Enhancing cognitive function in chronic TBI: The Role of α7 nicotinic acetylcholine receptor modulation.

Traumatic brain injury (TBI) results in several pathological changes within the hippocampus that result in adverse effects on learning and memory. Therapeutic strategies to enhance learning and memory after TBI are still in the early stages of clinical development. One strategy is to target the α7 nicotinic acetylcholine receptor (nAChR), which is highly expressed in the hippocampus and contributes to the formation of long-term memory. In our previous study, we found that AVL-3288, a positive allosteric modulator of the α7 nAChR, improved cognitive recovery in rats after moderate fluid-percussion injury (FPI). However, whether AVL-3288 improved cognitive recovery specifically through the α7 nAChR was not definitively determined. In this study we utilized Chrna7 knockout mice and compared their recovery to wild-type mice treated with AVL-3288 after TBI. We hypothesized that AVL-3288 treatment would improve learning and memory in wild-type mice, but not Chrna7-/- mice after TBI. Adult male C57BL/6 wild-type and Chrna7-/- mice received sham surgery or moderate controlled cortical impact (CCI) and recovered for 3 months. Mice were then treated with vehicle or AVL-3288 at 30 min prior to contextual fear conditioning. At 3 months after CCI, expression of α7 nAChR, choline acetyltransferase (ChAT), high-affinity choline transporter (ChT), and vesicular acetylcholine transporter (VAChT) were found to be significantly decreased in the hippocampus. Treatment of wild-type mice at 3 months after CCI with AVL-3288 significantly improved cue and contextual fear conditioning, whereas no beneficial effects were observed in Chrna7-/- mice. Parietal cortex and hippocampal atrophy were not improved with AVL-3288 treatment in either wild-type or Chrna7-/- mice. Our results indicate that AVL-3288 improves cognition during the chronic recovery phase of TBI through modulation of the α7 nAChR.

Effects of cylindrospermopsin, chlorpyrifos and their combination in a SH-SY5Y cell model concerning developmental neurotoxicity.

The cyanotoxin cylindrospermopsin (CYN) has been postulated to cause neurotoxicity, although the studies in this concern are very few. In addition, some studies in vitro indicate its possible effects on development. Furthermore, pesticides can be present in the same environmental samples as cyanotoxins. Therefore, chlorpyrifos (CPF) has been one of the most common pesticides used worldwide. The aim of this report was to study the effects of CYN, isolated and in combination with CPF, in a developmental neurotoxicity in vitro model. The human neuroblastoma SH-SY5Y cell line was exposed during 6 days of differentiation to both toxics to study their effects on cell viability and neurite outgrowth. To further evaluate effects of both toxicants on cholinergic signaling, their agonistic and antagonistic activities on the α7 homomeric nicotinic acetylcholine receptor (nAChR) were studied upon acute exposure. Moreover, a transcriptomic analysis by qPCR was performed after 6 days of CYN-exposure during differentiation. The results showed a concentration-dependent decrease on both cell viability and neurite outgrowth for both toxics isolated, leading to effective concentration 20 (EC20) values of 0.35 µM and 0.097 µM for CYN on cell viability and neurite outgrowth, respectively, and 100 µM and 58 µM for CPF, while the combination demonstrated no significant variations. In addition, 95 µM and 285 µM CPF demonstrated to act as an antagonist to nicotine on the nAChR, although CYN up to 2.4 µM had no effect on the efficacy of these receptors. Additionally, the EC20 for CYN (0.097 µM) on neurite outgrowth downregulated expression of the 5 genes NTNG2 (netrin G2), KCNJ11 (potassium channel), SLC18A3 (vesicular acetylcholine transporter), APOE (apolipoprotein E), and SEMA6B (semaphorin 6B), that are all important for neuronal development. Thus, this study points out the importance of studying the effects of CYN in terms of neurotoxicity and developmental neurotoxicity.

Cholinergic signaling influences the expression of immune checkpoint inhibitors, PD-L1 and PD-L2, and tumor hallmarks in human colorectal cancer tissues and cell lines.

BACKGROUND: Cancer cells express immunosuppressive molecules, such as programmed death ligands (PD-L)1 and PD-L2, enabling evasion from the host's immune system. Cancer cells synthesize and secrete acetylcholine (ACh), acting as an autocrine or paracrine hormone to promote their proliferation, differentiation, and migration. METHODS: We correlated the expression of PD-L1, PD-L2, cholinergic muscarinic receptor 3 (M3R), alpha 7 nicotinic receptor (α7nAChR), and choline acetyltransferase (ChAT) in colorectal cancer (CRC) tissues with the stage of disease, gender, age, risk, and patient survival. The effects of a muscarinic receptor blocker, atropine, and a selective M3R blocker, 4-DAMP, on the expression of immunosuppressive and cholinergic markers were evaluated in human CRC (LIM-2405, HT-29) cells. RESULTS: Increased expression of PD-L1, M3R, and ChAT at stages III-IV was associated with a high risk of CRC and poor survival outcomes independent of patients' gender and age. α7nAChR and PD-L2 were not changed at any CRC stages. Atropine and 4-DAMP suppressed the proliferation and migration of human CRC cells, induced apoptosis, and decreased PD-L1, PD-L2, and M3R expression in CRC cells via inhibition of EGFR and phosphorylation of ERK. CONCLUSIONS: The expression of immunosuppressive and cholinergic markers may increase the risk of recurrence of CRC. These markers might be used in determining prognosis and treatment regimens for CRC patients. Blocking cholinergic signaling may be a potential therapeutic for CRC through anti-proliferation and anti-migration via inhibition of EGFR and phosphorylation of ERK. These effects allow the immune system to recognize and eliminate cancer cells.

Accumulation of ß-Amyloid Leads to a Decrease in Lynx1 and Lypd6B Expression in the Hippocampus and Increased Expression of Proinflammatory Cytokines in the Hippocampus and Blood Serum.

Alzheimer's disease is a rapidly progressive neurodegenerative disease, the development of which is associated with the accumulation of ß-amyloid oligomers, dysfunction of the α7-nAChR nicotinic acetylcholine receptor, and activation of inflammation. Previously, we showed that the neuromodulator Lynx1, which belongs to the Ly6/uPAR family, competes with ß-amyloid(1-42) for binding to α7-nAChR. In this work, we studied the expression and localization of Ly6/uPAR family proteins in the hippocampus of 2xTg-AD transgenic mice that model AD and demonstrate increased amyloidosis in the brain. Using real-time PCR, we showed a decrease in the expression of the genes encoding Lynx1, Lypd6b, and the postsynaptic marker PSD95, as well as an increase in the expression of the TNFα gene in the hippocampus of 2xTg-AD mice. Histochemical analysis showed that, in the hippocampus of 2xTg-AD mice, Lynx1 does not colocalize with α7-nAChR, which can lead to the development of pathology when the receptor interacts with oligomeric ß-amyloid. In addition, in 2xTg-AD mice, activation of systemic inflammation was shown, which manifests itself in a decrease in the serum level of SLURP-1, a Ly6/uPAR family protein capable of regulating inflammatory processes, as well as in an increase in the content of proinflammatory cytokines TNFα and TNFß. Thus, α7-nAChR dysfunction and maintenance of the inflammatory microenvironment in the brain in Alzheimer's disease may be associated with a decrease in the expression of Ly6/uPAR family proteins that regulate α7-nAChR activity and inflammation.

Hypothalamic α7 nicotinic acetylcholine receptor (α7nAChR) is downregulated by TNFα-induced Let-7 overexpression driven by fatty acids.

The α7nAChR is crucial to the anti-inflammatory reflex, and to the expression of neuropeptides that control food intake, but its expression can be decreased by environmental factors. We aimed to investigate whether microRNA modulation could be an underlying mechanism in the α7nAchR downregulation in mouse hypothalamus following a short-term exposure to an obesogenic diet. Bioinformatic analysis revealed Let-7 microRNAs as candidates to regulate Chrna7, which was confirmed by the luciferase assay. Mice exposed to an obesogenic diet for 3 days had increased Let-7a and decreased α7nAChR levels, accompanied by hypothalamic fatty acids and TNFα content. Hypothalamic neuronal cells exposed to fatty acids presented higher Let-7a and TNFα levels and lower Chrna7 expression, but when the cells were pre-treated with TLR4 inhibitor, Let-7a, TNFα, and Chrna7 were rescued to normal levels. Thus, the fatty acids overload trigger TNFα-induced Let-7 overexpression in hypothalamic neuronal cells, which negatively regulates α7nAChR, an event that can be related to hyperphagia and obesity predisposition in mice.

Alpha 7 nicotinic acetylcholine receptors signaling boosts cell-cell interactions in macrophages effecting anti-inflammatory and organ protection.

Activation of the cholinergic anti-inflammatory pathway (CAP) via vagus nerve stimulation has been shown to improve acute kidney injury in rodent models. While alpha 7 nicotinic acetylcholine receptor (α7nAChR) positive macrophages are thought to play a crucial role in this pathway, their in vivo significance has not been fully understood. In this study, we used macrophage-specific α7nAChR-deficient mice to confirm the direct activation of α7nAChRs in macrophages. Our findings indicate that the administration of GTS-21, an α7nAChR-specific agonist, protects injured kidneys in wild-type mice but not in macrophage-specific α7nAChR-deficient mice. To investigate the signal changes or cell reconstructions induced by α7nAChR activation in splenocytes, we conducted single-cell RNA-sequencing of the spleen. Ligand-receptor analysis revealed an increase in macrophage-macrophage interactions. Using macrophage-derived cell lines, we demonstrated that GTS-21 increases cell contact, and that the contact between macrophages receiving α7nAChR signals leads to a reduction in TNF-α. Our results suggest that α7nAChR signaling increases macrophage-macrophage interactions in the spleen and has a protective effect on the kidneys.

Low-dose ketamine inhibits neuronal apoptosis and neuroinflammation in PC12 cells via α7nAChR mediated TLR4/MAPK/NF-κB signaling pathway.

Ketamine is commonly used for sedation, analgesia and anesthetics. Much evidence has shown that it has an immune-regulatory effect. The cholinergic anti-inflammatory pathway mediated by α7nAChR is a prominent target of anti-inflammatory therapy. However, whether ketamine suppresses inflammatory levels in nerve cells by activating α7nAChR remains unknown. Lipopolysaccharide (LPS) was used to establish the neuroinflammation model in PC12 cells in vitro, and α7nAChR siRNA was transfected into PC12 cells 30 min before LPS to inhibit gene expression of α7nAChR. PC12 cells were stimulated with LPS for 24 h, and the indicators were detected at 2 h after GTS-21 and ketamine were added. The results showed that LPS increased the proportion of PC12 cells apoptosis, activated TLR4/MAPK/NF-κB signaling pathway, and increased the expression of interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α). Ketamine reduced the ratio of early apoptosis and late apoptosis of PC12, inhibited the entry of P65 into the nucleus, decreased the activation of TLR4/MAPK/NF-κB and improved neuroinflammation. However, the ameliorating effects of ketamine on neuronal apoptosis and neuroinflammation were inhibited in the α7nAChRi group. This indicated that α7nAChR played a key role in the anti-inflammatory process of ketamine. Low-dose ketamine inhibited TLR4/MAPK/NF-κB by activating the α7nAChR-mediated cholinergic anti-inflammatory pathway, thereby producing the protective effect on neuronal apoptosis and neuroinflammation.

α7 nicotinic acetylcholine receptor agonist improved brain injury and impaired glucose metabolism in a rat model of ischemic stroke.

Vagus nerve stimulation through the action of acetylcholine can modulate inflammatory responses and metabolism. α7 Nicotinic Acetylcholine Receptor (α7nAChR) is a key component in the biological functions of acetylcholine. To further explore the health benefits of vagus nerve stimulation, this study aimed to investigate whether α7nAChR agonists offer beneficial effects against poststroke inflammatory and metabolic changes and to identify the underlying mechanisms in a rat model of stroke established by permanent cerebral ischemia. We found evidence showing that pretreatment with α7nAChR agonist, GTS-21, improved poststroke brain infarction size, impaired motor coordination, brain apoptotic caspase 3 activation, dysregulated glucose metabolism, and glutathione reduction. In ischemic cortical tissues and gastrocnemius muscles with GTS-21 pretreatment, macrophages/microglia M1 polarization-associated Tumor Necrosis Factor-α (TNF-α) mRNA, Cluster of Differentiation 68 (CD68) protein, and Inducible Nitric Oxide Synthase (iNOS) protein expression were reduced, while expression of anti-inflammatory cytokine IL-4 mRNA, and levels of M2 polarization-associated CD163 mRNA and protein were increased. In the gastrocnemius muscles, stroke rats showed a reduction in both glutathione content and Akt Serine 473 phosphorylation, as well as an elevation in Insulin Receptor Substrate-1 Serine 307 phosphorylation and Dynamin-Related Protein 1 Serine 616 phosphorylation. GTS-21 reversed poststroke changes in the gastrocnemius muscles. Overall, our findings, provide further evidence supporting the neuroprotective benefits of α7nAChR agonists, and indicate that they may potentially exert anti-inflammatory and metabolic effects peripherally in the skeletal muscle in an acute ischemic stroke animal model.

Human-specific duplicate CHRFAM7A gene is associated with more severe osteoarthritis and amplifies pain behaviours.

OBJECTIVES: CHRFAM7A is a uniquely human fusion gene that functions as a dominant negative regulator of alpha 7 acetylcholine nicotinic receptor (α7nAChR) in vitro. This study determined the impact of CHRFAM7A on α7nAChR agonist responses, osteoarthritis (OA) severity and pain behaviours and investigated mechanisms. METHODS: Transgenic CHRFAM7A (TgCHRFAM7A) mice were used to determine the impact of CHRFAM7A on knee OA histology, pain severity in OA and other pain models, response to nAchR agonist and IL-1ß. Mouse and human cells were used for mechanistic studies. RESULTS: Transgenic (Tg) TgCHRFAM7A mice developed more severe structural damage and increased mechanical allodynia than wild type (WT) mice in the destabilisation of medial meniscus model of OA. This was associated with a decreased suppression of inflammation by α7nAchR agonist. TgCHRFAM7A mice displayed a higher basal sensitivity to pain stimuli and increased pain behaviour in the monoiodoacetate and formalin models. Dorsal root ganglia of TgCHRFAM7A mice showed increased macrophage infiltration and expression of the chemokine fractalkine and also had a compromised antinociceptive response to the α7nAchR agonist nicotine. Both native CHRNA7 and CHRFAM7A subunits were expressed in human joint tissues and the CHRFAM7A/CHRNA7 ratio was increased in OA cartilage. Human chondrocytes with two copies of CHRFAM7A had reduced anti-inflammatory responses to nicotine. CONCLUSION: CHRFAM7A is an aggravating factor for OA-associated inflammation and tissue damage and a novel genetic risk factor and therapeutic target for pain.

Short-term exposure of HFD depresses intestinal cholinergic anti-inflammatory activity through hypothalamic inflammation in mice.

High-fat diet (HFD) exposure has been proven to impair vagus nerve function. However, it is not yet known whether the HFD challenge impacts vagal efferent-based intestinal cholinergic anti-inflammation activity. This investigation aims to evaluate the effect of HFD on intestinal cholinergic anti-inflammatory activity in mice. Mice with or without intracerebroventricular treatment with an antibody against toll-like receptor 4 (TLR4) were fed with HFD or standard chow for 2 weeks. Vagus nerve-based anti-inflammatory activity was analyzed by heart rate variability. Acetylcholine (ACh) content, nicotinic acetylcholine receptor α7 subtype (α7nAChR), and pro-inflammatory cytokines were analyzed by biochemical kits or qRT-PCR. HFD feeding mice exhibit a significant increase in high frequency (HF) and a decrease in the ratio of low frequency/HF, which were accompanied by lower ACh levels and α7nAChR mRNA expression in the intestinal segments. However, anti-TLR4 antibody-treated HFD mice showed normal ACh levels and α7nAChR mRNA expression in the intestinal segments. Moreover, TNF-α production in small intestine was significantly reduced in HFD + antibody group compared with HFD + vehicle group. Collectively, our present results reveal that HFD challenge depresses intestinal cholinergic anti-inflammatory activity, which is mediated by hypothalamic inflammation. Impairment of intestinal cholinergic anti-inflammatory pathway is the cause of intestinal low-grade inflammation by HFD consumption.

Impaired autophagy flux by lncRNA NEAT1 is critical for inflammation factors production in human periodontal ligament stem cells with nicotine treatment.

BACKGROUND AND OBJECTIVES: Periodontitis is the top reason for tooth loss, and smoking significantly increases severe periodontitis risk. Defective autophagy has been reported to play a vital role in periodontitis. This study aimed to elucidate the relationship between autophagy and inflammation factors production in nicotine-treated periodontal ligament stem cells (PDLSCs) and the underlying mechanism. METHODS: In this study, transmission electron microscopy, immunofluorescence, and the mCherry-GFP-LC3 plasmid were used to study autophagy flux. The gene levels of inflammation factors and long noncoding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) were detected by quantitative real-time PCR (qRT-PCR). Western blot was performed to assess the protein levels of autophagic markers and α7 nicotinic acetylcholine receptor (α7nAChR). RESULTS: We found that nicotine impaired autophagosome-lysosome fusion and lysosome functions to block autophagy flux, contributing to inflammatory factors production in nicotine-treated PDLSCs. Moreover, nicotine upregulated NEAT1 by activating α7nAChR. NEAT1 decreased autophagy flux by downregulating syntaxin 17 (STX17). CONCLUSION: Our data indicate that NEAT1-decreased autophagy flux is pivotal for inflammation factors production in nicotine-treated PDLSCs.

Insights Into the Differential Desensitization of α4ß2 Nicotinic Acetylcholine Receptor Isoforms Obtained With Positive Allosteric Modulation of Mutant Receptors.

The development of highly efficacious positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptors (nAChR) has proven useful in defining the ligand dependence of the conformational dynamics of α7 receptors. No such effective modulators are known to exist for the α4ß2 nAChR of the brain, limiting our ability to understand the importance of desensitization for the activity profile of specific ligands. In this study, we used mutant ß2 subunits that allowed the use of the α7 PAM 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS) to probe the desensitizing effects of nicotinic ligands on the two forms of α4ß2 receptors; high sensitivity (HS) (two α4 and three ß2 subunits) and low sensitivity (LS) (three α4 and two ß2 subunits). A total of 28 different ligands of 8 different categories, based on activity and selectivity, were tested for their ability to induce TQS-sensitive desensitization of HS and LS α4ß2 receptors. Results confirm that HS α4ß2 receptor responses are strongly limited by desensitization, by at least an order of magnitude more so than the responses of LS receptors. The activation of α4ß2 receptors by the smoking-cessation drugs cytisine and varenicline is strongly limited by desensitization, as is the activation of LS receptors by the HS-selective agonists 6-[5-[(2S)-2-Azetidinylmethoxy]-3-pyridinyl]-5-hexyn-1-ol dihydrochloride and 4-(5-ethoxy-3-pyridinyl)-N-methyl-(3E)-3-buten-1-amine difumarate. The evaluation of drugs previously identified as α7-selective agonists revealed varying patterns of α4ß2 cross-desensitization that were predictive of the effects of these drugs on the activation of wild-type α4ß2 receptors by acetylcholine, supporting the utility of TQS-sensitive receptors for the development of focused therapeutics. SIGNIFICANCE STATEMENT: To varying degrees, ligands regulate the balance of active and desensitized states of the two forms of the primary nAChR subtypes in brain. Using mutant beta subunits, an allosteric modulator can reverse ligand-induced desensitization, revealing the differential desensitization of the receptors by specific ligands. This study shows that drugs believed to be selective for therapeutic targets may cross-desensitize other targets and that, within a class of drugs, improved specificity can be achieved by using agents that reduce such cross-desensitization.

[Acupuncture mitigates ocular surface inflammatory response via α7nAChR/NF-κB p65 signaling in dry eye guinea pigs].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the ocular surface inflammation and α7 nicotinic acetylcholine receptor (α7nAChR) / nuclear factor kappa-B (NF-κB) p65 signal pathway in guinea pigs with dry eye, so as to explore its underlying mechanism. METHODS: A total of 32 male British tricolor short haired guinea pigs were randomized into blank control, model, EA and sham acupuncture groups, with 8 guinea pigs in each group. The dry eye model was established by subcutaneous injection of scopolamine hydrobromide solution (0.6 mg/0.2 mL each time, 4 times a day for 10 days). Guinea pigs of the EA group was treated with EA at bilateral "Cuanzhu" (BL2) and "Taiyang" (HN5), and manual acupuncture at bilateral "Jingming" (BL1), "Sizhukong" (SJ23), "Tongziliao" (GB1) for 15 min, once daily for 14 days. For animals of the sham acupuncture group, a blunt needle was used to prick the skin surface of the acupoints, the acupoint selection and stimulation time were the same as those in the EA group. Before and after modeling and after the intervention, the breakup time (BUT) of lacrimal film, sodium fluorescein coloring (Fl) state of corneal epithelium and phenol red thread (PRT) moist length were recorded for assessing the severity of dry eye. The density of activated immune cells around the corneal epithelial stromal cells was determined by corneal confocal microscopy. The contents of interleukin-4 (IL-4), IL-6, IL-10, tumor necrosis factor α (TNF-α) in the cornea and lacri-mal gland tissues were determined by ELISA, and the expression levels of α7nAChR and NF-κB p65 in the cornea and lacrimal gland were detected by immunohistochemistry and Western blot, separately. RESULTS: Compared with the blank control group, the corneal Fl, density of activated immune cells of corneal epithelium, contents of IL-6, IL-10 and TNF-α in both corneal and lacrimal gland tissues, NF-κB p65 cell positive rate and protein expression of lacrimal gland and corneal tissues were significantly increased (P<0.01, P<0.05), while the BUT, PRT and lacrimal gland α7nAChR cell positive rate considerably decreased (P<0.01) in the model group. In comparison with the model group, the level of corneal Fl, density of the activated immune cells of corneal epithelium, contents of corneal and lacrimal IL-6 and TNF-α, and corneal and lacrimal NF-κB p65 cell positive rates and protein expressions were remarkably down-regulated in the EA group (P<0.01, P<0.05), rather than in the sham acupuncture group (P>0.05) except content of corneal IL-10, lacrimal NF-κB p65 cell positive rate and lacrimal α7nAChR protein expression, whereas the levels of BUT, PRT, corneal and lacrimal IL-10 and corneal and lacrimal α7nAChR cell positive rates and protein expressions significantly up-regulated in the EA group (P<0.01, P<0.05), rather than in the sham acupuncture group (P>0.05) except corneal TNF-α and corneal NF-κB p65 protein expression. CONCLUSION: EA can improve corneal and lacrimal function in dry eye guinea pigs, which may be associated with its actions in increasing the expression of α7nAChR, inhibiting the nuclear translocation of NF-κB, and reducing the activated immune cells and inflammatory reaction.