The role of α7nAChR in controlling the anti-inflammatory/anti-arthritic action of galantamine

Galantamine mitigates testicular injury and disturbed spermatogenesis in adjuvant arthritic rats via modulating apoptosis, inflammatory signals, and IL-6/JAK/STAT3/SOCS3 signaling

Rheumatoid arthritis (RA) affects the joints and the endocrine system via persistent immune system activation. RA patients have a higher frequency of testicular dysfunction, impotence, and decreased libido. This investigation aimed to evaluate the efficacy of galantamine (GAL) on testicular injury secondary to RA. Rats were allocated into four groups: control, GAL (2 mg/kg/day, p.o), CFA (0.3 mg/kg, s.c), and CFA + GAL. Testicular injury indicators, such as testosterone level, sperm count, and gonadosomatic index, were evaluated. Inflammatory indicators, such as interleukin-6 (IL-6), p-Nuclear factor kappa B (NF-κB p65), and anti-inflammatory cytokine interleukin-10 (IL-10), were assessed. Cleaved caspase-3 expression was immunohistochemically investigated. Protein expressions of Janus kinase (JAK), signal transducers and activators of transcription (STAT3), and Suppressors of Cytokine Signaling 3 (SOCS3) were examined by Western blot analysis. Results show that serum testosterone, sperm count, and gonadosomatic index were increased significantly by GAL. Additionally, GAL significantly diminished testicular IL-6 while improved IL-10 expression relative to CFA group. Furthermore, GAL attenuated testicular histopathological abnormalities by CFA and downregulated cleaved caspase-3 and NF-κB p65 expressions. It also downregulated JAK/STAT3 cascade with SOCS3 upregulation. In conclusion, GAL has potential protective effects on testicular damage secondary to RA via counteracting testicular inflammation, apoptosis, and inhibiting IL-6/JAK/STAT3/SOCS3 signaling.

Alzheimer Disease Treatment With Acetylcholinesterase Inhibitors and Incident Age-Related Macular Degeneration

Importance

Age-related macular degeneration (AMD) is a serious and common ophthalmologic disorder that is hypothesized to result, in part, from inflammatory reactions in the macula. Alzheimer disease (AD) treatment, acetylcholinesterase inhibitors (AChEIs), have anti-inflammatory effects and it remains unclear if they modify the risk of AMD.

Objective

To investigate the association between AChEI medications and the incidence of AMD.

Design, Setting, and Participants

This propensity score-matched retrospective cohort study took place at health care facilities within the US Department of Veterans Affairs (VA) health care system from January 2000 through September 2023. Participants included patients diagnosed with AD between ages 55 and 80 years with no preexisting diagnosis of AMD in the VA database.

Exposure

AChEIs prescription dispensed as pharmacologic treatments for AD.

Main Outcomes and Measure

The first diagnosis of AMD.

Results

A total of 21 823 veterans with AD (mean [SD] age, 72.3 [6.1] years; 21 313 male participants [97.7%] and 510 female participants [2.3%]) were included. Propensity score-matched Cox model reveals each additional year of AChEI treatment was associated with a 6% lower hazard of AMD (hazard ratio, 0.94; 95% CI, (0.89-0.99).

Conclusions and Relevance

This observational study reports a small reduction in the risk of AMD among veterans with AD receiving AChEIs. Randomized clinical trials would be needed to determine if there is a cause-and-effect relationship and further research is required to validate these findings across diverse populations.

The neurobiology and therapeutic potential of multi-targeting β-secretase, glycogen synthase kinase 3β and acetylcholinesterase in Alzheimer's disease

Alzheimer's Disease (AD) is the most common form of dementia, affecting almost 50 million of people around the world, characterized by a complex and age-related progressive pathology with projections to duplicate its incidence by the end of 2050. AD pathology has two major hallmarks, the amyloid beta (Aβ) peptides accumulation and tau hyperphosphorylation, alongside with several sub pathologies including neuroinflammation, oxidative stress, loss of neurogenesis and synaptic dysfunction. In recent years, extensive research pointed out several therapeutic targets which have shown promising effects on modifying the course of the disease in preclinical models of AD but with substantial failure when transposed to clinic trials, suggesting that modulating just an isolated feature of the pathology might not be sufficient to improve brain function and enhance cognition. In line with this, there is a growing consensus that an ideal disease modifying drug should address more than one feature of the pathology. Considering these evidence, β-secretase (BACE1), Glycogen synthase kinase 3β (GSK-3β) and acetylcholinesterase (AChE) has emerged as interesting therapeutic targets. BACE1 is the rate-limiting step in the Aβ production, GSK-3β is considered the main kinase responsible for Tau hyperphosphorylation, and AChE play an important role in modulating memory formation and learning. However, the effects underlying the modulation of these enzymes are not limited by its primarily functions, showing interesting effects in a wide range of impaired events secondary to AD pathology. In this sense, this review will summarize the involvement of BACE1, GSK-3β and AChE on synaptic function, neuroplasticity, neuroinflammation and oxidative stress. Additionally, we will present and discuss new perspectives on the modulation of these pathways on AD pathology and future directions on the development of drugs that concomitantly target these enzymes.

Nicotine Decreases Nerve Regeneration and Pain Behaviors via PTEN and Downstream Inflammation-Related Pathway in Two Rat Nerve Injury Models

Neuropathic pain is stubborn and associated with the peripheral nerve regeneration process. Nicotine has been found to reduce pain, but whether it is involved in the regulation of nerve regeneration and the underlying mechanism are unknown. In this study, we examined the mechanical allodynia thermal hyperalgesia together with the peripheral nerve regeneration after nicotine exposure in two rat neuropathic pain models. In the spinal nerve ligation model, in which anatomic nerve regeneration can be easily observed, nicotine reduced anatomic measures of regeneration as well as expression of regeneration marker growth-associated protein 43 (GAP43). In the tibial nerve crush model, nicotine treatment significantly suppressed GAP43 expression and functional reinnervation as measured by myelinated action potential and electromyography of gastrocnemius. In both models, nicotine treatment reduced macrophage density in the sensory ganglia and peripheral nerve. These effects of nicotine were reversed by the selective α7 nicotinic acetylcholine receptor (nAChR) blocker methyllycaconitine. In addition, nicotine significantly elevated expression of PTEN (the phosphatase and tensin homolog deleted on chromosome 10), a key player in both regeneration and pain. Pharmacological interference of PTEN could regulate GAP43 expression, pain-related behaviors, and macrophage infiltration in a nicotine-treated nerve crush model. Our results reveal that nicotine and its α7-nAChR regulate both peripheral nerve regeneration process and pain though PTEN and the downstream inflammation-related pathway.

Magnoflorine Ameliorates Collagen-Induced Arthritis by Suppressing the Inflammation Response via the NF-κB/MAPK Signaling Pathways

Objective

Magnoflorine (Mag) has been reported to have anxiolytics, anti-cancer, and anti-inflammatory properties. In this study, we aim to investigate the effects of Mag on the rheumatoid arthritis (RA) and explore the underlying mechanism using a collagen-induced arthritis (CIA) mouse model and a lipopolysaccharide (LPS)-stimulated macrophage inflammation model.

Methods

The in vivo effects of Mag on CIA were studied by inducing CIA in a mouse model using DBA/1J mice followed by treatment with vehicle, methotrexate (MTX, 1 mg/kg/d), and Mag (5 mg/kg/d, 10 mg/kg/d, and 20 mg/kg/d), and the in vitro effects of Mag on macrophages were examined by stimulation of RAW264.7 cells line and peritoneal macrophages (PMs) by LPS in the presence of different concentrations of Mag. Network pharmacology and molecular docking was then performed to predict the the binding ability between Mag and its targets. Inflammatory mediators were assayed by quantitative real-time PCR and enzyme linked immunosorbent assay (ELISA). Signaling pathway changes were subsequently determined by Western blotting and immunohistochemistry (IHC).

Results

In vivo experiments demonstrated that Mag decreased arthritis severity scores, joints destruction, and macrophages infiltration into the synovial tissues of the CIA mice. Network pharmacology analysis revealed that Mag interacted with TNF-α, IL-6, IL-1β, and MCP-1. Consistent with this, analysis of the serum, synovial tissue of the CIA mice, and the supernatant of the cultured RAW264.7 cells and PMs showed that Mag suppressed the expression of TNF-α, IL-6, IL-1β, MCP-1, iNOS, and IFN-β. Furthermore, Mag attenuated the phosphorylation of p65, IκBα, ERK, JNK, and p38 MAPKs in the synovial tissues of the CIA mice and LPS-stimulated RAW 264.7 cells.

Conclusion

Mag may exert anti-arthritic and anti-inflammatory effects by inhibiting the activation of NF-κB and MAPK signaling pathways.

Cholinergic dysfunction-induced insufficient activation of alpha7 nicotinic acetylcholine receptor drives the development of rheumatoid arthritis through promoting protein citrullination via the SP3/PAD4 pathway

Both cholinergic dysfunction and protein citrullination are the hallmarks of rheumatoid arthritis (RA), but the relationship between the two phenomena remains unclear. We explored whether and how cholinergic dysfunction accelerates protein citrullination and consequently drives the development of RA. Cholinergic function and protein citrullination levels in patients with RA and collagen-induced arthritis (CIA) mice were collected. In both neuron-macrophage coculture system and CIA mice, the effect of cholinergic dysfunction on protein citrullination and expression of peptidylarginine deiminases (PADs) was assessed by immunofluorescence. The key transcription factors for PAD4 expression were predicted and validated. Cholinergic dysfunction in the patients with RA and CIA mice negatively correlated with the degree of protein citrullination in synovial tissues. The cholinergic or alpha7 nicotinic acetylcholine receptor (α7nAChR) deactivation and activation resulted in the promotion and reduction of protein citrullination in vitro and in vivo, respectively. Especially, the activation deficiency of α7nAChR induced the earlier onset and aggravation of CIA. Furthermore, deactivation of α7nAChR increased the expression of PAD4 and specificity protein-3 (SP3) in vitro and in vivo. Our results suggest that cholinergic dysfunction-induced deficient α7nAChR activation, which induces the expression of SP3 and its downstream molecule PAD4, accelerating protein citrullination and the development of RA.

α7 nicotinic acetylcholine receptor agonist GTS-21 attenuates DSS-induced intestinal colitis by improving intestinal mucosal barrier function

Background and aims

Cholinergic output, which could modulate innate immune responses through stimulation of α7 nicotinic acetylcholine receptor (α7nAChR), might be a target to minimize tissue damage in autoimmune disease. GTS-21, a selective α7nAChR agonist, has previously demonstrated to inhibit synovium inflammation in rheumatoid arthritis. In this study, we investigated the effect of GTS-21 on dextran sulfate sodium (DSS)-induced colitis model and its potential mechanism.

Methods

Male BABL/c mice (n = 32) were randomly divided into four groups: normal control group, DSS-induced colitis group, GTS-21 treatment with or without α7nAChR antagonist α-BGT treatment group. Disease activity index (DAI), histological activity index (HAI) and colonic macroscopic damage were evaluated. Fluorescein isothiocyanate (FITC)–dextran assay was applied to measure intestinal permeability. The expressions of tight junction (TJ) proteins and NF-κB associated proteins were detected by Western blot.

Results

GTS-21 could decrease DAI scores, HAI scores, intestinal permeability and reduce the intestinal bacterial translocation in DSS-induced colitis group, whereas α7nAChR antagonist α-BGT could impair this protective influence. The expressions of TJ proteins were increased with administration of GTS-21 both in vivo and in vitro. Furthermore, GTS-21 also inhibited the NF-қB activation in intestinal epithelial cells and colitis model, while α-BGT reversed the inhibitory effect.

Conclusion

The α7nAChR agonist GTS-21 attenuated DSS-induced colitis through increasing expressions of TJ proteins in colon tissues and improved intestinal barrier function, which might be due to  modulating NF-қB activation in intestinal epithelial cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00485-6.

Predictive value of serum cholinesterase in the mortality of acute pancreatitis: A retrospective cohort study

BACKGROUND

Severe acute pancreatitis has a high mortality of 20%-40%, but there is a lack of optimal prognostic biomarker for the severity of acute pancreatitis (AP) or mortality. This study is designed to investigate the relationship between serum cholinesterase (ChE) level and poor outcomes of AP.

METHODS

A total of 1904 AP patients were screened in the study, and we finally got 692 patients eligible for analysis. Patients were divided into 2 groups based on serum ChE. The primary outcome was mortality, and multivariable logistic regression analysis for mortality was completed. Additionally, we used receiver operating characteristic (ROC) curve analysis to clarify the predictive value of serum ChE for mortality and organ failure.

RESULTS

Three hundred and seventy eight patients and 314 patients were included in the ChE-low and ChE-normal group, respectively. Patients in the ChE-low group were older (46.68 ± 12.70 vs. 43.56 ± 12.13 years old, p = .001) and had a lower percentage of man (62.4% vs. 71.0%, p = .017) when compared to the ChE-normal group. Mortality was significantly different in two groups (10.3% vs. 0.0%, p < .001). Moreover, organ failure also differed significantly in two groups (46.6% vs. 8.6%, p < .001). Decreased ChE level was independently associated with mortality in acute pancreatitis (odds ratio: 0.440; 95% confidence interval, 0.231, 0.838, p = .013). The area under the curve of serum ChE was 0.875 and 0.803 for mortality and organ failure, respectively.

CONCLUSIONS

Lower level of serum ChE was independently associated with the severity and mortality of AP.

The Effect of α7nAChR Signaling on T Cells and Macrophages and Their Clinical Implication in the Treatment of Rheumatic Diseases

Rheumatoid arthritis (RA) is one of the most common autoimmune disease and until now, the etiology and pathogenesis of RA is not fully understood, although dysregulation of immune cells is one of the leading cause of RA-related pathological changes. Based on current understanding, the priority of anti-rheumatic treatments is to restore immune homeostasis. There are several anti-rheumatic drugs with immunomodulatory effects available nowadays, but most of them have obvious safety or efficacy shortcomings. Therefore, the development of novel anti-rheumatic drugs is still in urgently needed. Cholinergic anti-inflammatory pathway (CAP) has been identified as an important aspect of the so-called neuro-immune regulation feedback, and the interaction between acetylcholine and alpha 7 nicotinic acetylcholine receptor (α7nAChR) serves as the foundation for this signaling. Consistent to its immunomodulatory functions, α7nAChR is extensively expressed by immune cells. Accordingly, CAP activation greatly affects the differentiation and function of α7nAChR-expressing immune cells. As a result, targeting α7nAChR will bring profound therapeutic impacts on the treatment of inflammatory diseases like RA. RA is widely recognized as a CD4+ T cells-driven disease. As a major component of innate immunity, macrophages also significantly contribute to RA-related immune abnormalities. Theoretically, manipulation of CAP in immune cells is a feasible way to treat RA. In this review, we summarized the roles of different T cells and macrophages subsets in the occurrence and progression of RA, and highlighted the immune consequences of CAP activation in these cells under RA circumstances. The in-depth discussion is supposed to inspire the development of novel cell-specific CAP-targeting anti-rheumatic regimens.

The role of the cholinergic anti-inflammatory pathway in autoimmune rheumatic diseases

The cholinergic anti-inflammatory pathway (CAP) is a classic neuroimmune pathway, consisting of the vagus nerve, acetylcholine (ACh)-the pivotal neurotransmitter of the vagus nerve-and its receptors. This pathway can activate and regulate the activities of immune cells, inhibit cell proliferation and differentiation, as well as suppress cytokine release, thereby playing an anti-inflammatory role, and widely involved in the occurrence and development of various diseases; recent studies have demonstrated that the CAP may be a new target for the treatment of autoimmune rheumatic diseases. In this review, we will summarize the latest progress with the view of figuring out the role of the cholinergic pathway and how it interacts with inflammatory reactions in several autoimmune rheumatic diseases, and many advances are results from a wide range of experiments performed in vitro and in vivo.

Pharmacological Influencing of The Cholinergic Anti-inflammatory Pathway in Infectious Diseases and Inflammatory Pathologies

The cholinergic anti-inflammatory pathway is a part of the parasympathetic nervous system and it can also be entitled as an anti-inflammatory reflex. It consists of terminations of the vagal nerve into blood, acetylcholine released from the terminations, macrophages and other cells having α7 nicotinic acetylcholine receptor (α7 nAChR), calcium ions crossing through the receptor and interacting with nuclear factors, and erythrocytes with acetylcholinesterase (AChE) terminating the neurotransmission. Stopping of inflammatory cytokines production is the major task for the cholinergic antiinflammatory pathway. The cholinergic anti-inflammatory pathway can be stimulated or suppressed by agonizing or antagonizing α7 nAChR or by inhibition of AChE. This review is focused on cholinergic anti-inflammatory pathway regulation by drugs. Compounds that inhibit cholinesterases (for instance, huperzine, rivastigmine, galantamine), and their impact on the cholinergic anti-inflammatory pathway are discussed here and a survey of actual literature is provided.

Cholinergic anti-inflammatory pathway and connective tissue diseases

Connective tissue diseases (CTDs) consist of an extensive range of heterogeneous medical conditions, which are caused by immune-mediated chronic inflammation and influences the various connective tissues of the body. They include rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, vasculitis, Sjögren's syndrome, Behcet's disease, and many other autoimmune CTDs. To date, several anti-inflammatory approaches have been developed to reduce the severity of inflammation or its subsequent organ manifestations. As a logical mechanism to harnesses the undesired inflammation, some studies investigated the role of the intrinsic cholinergic anti-inflammatory pathway (CAP) in the modulation of chronic inflammation. Many different experimental and clinical models have been developed to evaluate the therapeutic significance of the CAP in CTDs. On the other hand, an issue that is less emphasized in this regard is the presence of autonomic neuropathy in CTDs, which influences the efficiency of CAP in such clinical settings. This condition occurs during CTDs and is a well-known complication of patients suffering from them. The advantages and limitations of CAP in the control of inflammatory responses and its possible therapeutic benefits in the treatment of CTDs are the main subjects of the current study. Therefore, this narrative review article is provided based on the recent findings of the complicated role of CAP in CTDs which were retrieved by searching Science Direct, PubMed, Google Scholar, and Web of Science. It seems that delineating the complex influences of CAP would be of great interest in designing novel surgical or pharmacological therapeutic strategies for CTDs therapy.

The cholinergic system in joint health and osteoarthritis: a narrative-review

Osteoarthritis (OA) poses a major health and economic burden worldwide due to an increasing number of patients and the unavailability of disease-modifying drugs. In this review, the latest understanding of the involvement of the cholinergic system in joint homeostasis and OA will be outlined. First of all, the current evidence on the presence of the cholinergic system in the normal and OA joint will be described. Cholinergic innervation as well as the non-neuronal cholinergic system are detected. In a variety of inflammatory diseases, the classic cholinergic anti-inflammatory pathway lately received a lot of attention as via this pathway cholinergic agonists can reduce inflammation. The role of this cholinergic anti-inflammatory pathway in the context of OA will be discussed. Activation of this pathway improved the progression of the disease. Secondly, chondrocyte hypertrophy plays a pivotal role in osteophyte formation and OA development; the impact of the cholinergic system on hypertrophic chondroblasts and endochondral ossification will be evaluated. Cholinergic stimulation increased chondrocyte proliferation, delayed chondrocyte differentiation and caused early mineralisation. Moreover, acetylcholinesterase and butyrylcholinesterase affect the endochondral ossification via an acetylcholine-independent pathway. Thirdly, subchondral bone is critical for cartilage homeostasis and metabolism; the cholinergic system in subchondral bone homeostasis and disorders will be explored. An increase in osteoblast proliferation and osteoclast apoptosis is observed. Lastly, current therapeutic strategies for OA are limited to symptom relief; here the impact of smoking on disease progression and the potential of acetylcholinesterase inhibitors as candidate disease-modifying drug for OA will be discussed.

Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity

Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.

Neuroprotective role of galantamine with/without physical exercise in experimental autoimmune encephalomyelitis in rats

AIMS

The fact that physical activity besides central cholinergic enhancement contributes in improving neuronal function and spastic plasticity, recommends the use of the anticholinesterase and cholinergic drug galantamine with/without exercise in the management of the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS).

MATERIALS AND METHODS

Sedentary and 14 days exercised male Sprague Dawley rats were subjected to EAE. Hereafter, exercised rats continued on rotarod for 30 min for 17 consecutive days. At the onset of symptoms (day 13), EAE sedentary/exercised groups were subdivided into untreated and post-treated with galantamine. The disease progression was assessed by EAE score, motor performance, and biochemically using cerebrospinal fluid (CSF). Cerebellum and brain stem samples were used for histopathology and immunohistochemistry analysis.

KEY FINDINGS

Galantamine decreased EAE score of sedentary/exercised rats and enhanced their motor performance. Galantamine with/without exercise inhibited CSF levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6), and Bcl-2-associated X protein (Bax), besides caspase-3 and forkhead box P3 (Foxp3) expression in the brain stem. Contrariwise, it has elevated CSF levels of brain derived neurotrophic factor (BDNF) and B-cell lymphoma (Bcl-2) and enhanced remyelination of cerebral neurons. Noteworthy, exercise boosted the drug effect on Bcl-2 and Bax.

SIGNIFICANCE

The neuroprotective effect of galantamine against EAE was associated with anti-inflammatory and anti-apoptotic potentials, along with increasing BDNF and remyelination. It also normalized regulatory T-cells levels in the brain stem. The impact of the add-on of exercise was markedly manifested in reducing neuronal apoptosis.

The Role of α7nAChR-Mediated Cholinergic Anti-inflammatory Pathway in Immune Cells

Alpha 7 nicotinic acetylcholine receptor (α7nAChR) is widely distributed in the nervous and non-cholinergic immune systems. It is necessary for the cholinergic transmitter to participate in the regulation of inflammatory response and is the key element of cholinergic anti-inflammatory pathway (CAP). Because of the profound impact of CAP on the immune system, α7nAChR is considered as a potential therapeutic target for the treatment of inflammatory diseases. Available evidences confirmed that manipulation of CAP by activating α7nAChR with either endogenous acetylcholine (ACh) or cholinergic agonists can substantially alleviate inflammatory responses both in vivo and in vitro. However, the mechanism through which CAP curbs the excessive pro-inflammatory responses and maintains immune homeostasis is not fully understood. Obtained clues suggest that the crosstalk between CAP and classical inflammatory pathways is the key to elucidate the anti-inflammatory mechanism, and the impacts of CAP activation in α7nAChR-expressing immune cells are the foundation of the immunoregulatory property. In this article, we review and update the knowledge concerning the progresses of α7nAChR-based CAP, including α7nAChR properties, signal transductions, interactions with classic immune pathways, and immunoregulatory functions in different immune cells. Certain critical issues to be addressed are also highlighted. By providing a panoramic view of α7nAChR, the summarized evidences will pave the way for the development of novel anti-inflammatory reagents and strategy and inspire further researches.