Cholinergic stimulation of the immune system protects against lethal infection by Salmonella enterica serovar Typhimurium

Effect of acetylcholinesterase inhibition on immune cells in the murine intestinal mucosa

The gastrointestinal tract (GI) is the largest immune organ whose function is controlled by a complex network of neurons from the enteric nervous system (ENS) as well as the sympathetic and parasympathetic system. Evolving evidence indicates that cross-communication between gut-innervating neurons and immune cells regulates many essential physiological functions including protection against mucosal infections. We previously demonstrated that following paraoxon treatment, 70 % of the mice were able to survive an oral infection with S. typhimurium, a virulent strain of Salmonella enterica serovar Typhimurium. The present study aims to investigate the effect that rivastigmine, a reversible AChE inhibitor used for the treatment of neurodegenerative diseases, has on the murine immune defenses of the intestinal mucosa. Our findings show that, similar to what is observed with paraoxon, administration of rivastigmine promoted the release of secretory granules from goblet and Paneth cells, resulting in increased mucin layer. Surprisingly, however, and unlike paraoxon, rivastigmine treatment did not affect overall mortality of infected mice. In order to investigate the mechanistic basis for the differential effects observed between paraoxon and rivastigmine, we used multi-color flowcytometric analysis to characterize the immune cell landscape in the intraepithelial (IE) and lamina propria (LP) compartments of intestinal mucosa. Our data indicate that treatment with paraoxon, but not rivastigmine, led to an increase of resident CD3+CD8+ T lymphocytes in the ileal mucosa (epithelium and lamina propria) and CD11b- CD11c+ dendritic cells in the LP. Our findings indicate the requirement for persistent cholinergic pathway engagement to effect a change in the cellular landscape of the mucosal tissue that is necessary for protection against lethal bacterial infections. Moreover, optimal protection requires a collaboration between innate and adaptive mucosal immune responses in the intestine.

Capturing the antimicrobial profile of Paeonia officinalis, Jasminum officinale and Rosa damascene against methicillin resistant Staphylococcus aureus with metabolomics analysis and network pharmacology

In the current study, we evaluated the in vitro antibacterial efficacy of the roots' extracts of Jasminum officinale, Rosa damascene and Paeonia officinalis against MRSA (methicillin-resistant Staphylococcus aureus) by well diffusion technique. The root extract of P. officinalis exerted a potent anti-MRSA with MIC 0.4673 µg/ml, while both J. officinale and R. damascene exhibited very weak activity. Therefore, chemical profiling of the crude extract P. officinalis roots assisted by LC-HR-ESI-MS was performed and led to the dereplication of twenty metabolites of different classes, in which terpenes are the most abundant compounds. On a molecular level, network pharmacology was used to determine the targets of active metabolites to bacterial infections, particularly MRSA. Online databases PubChem, UniProt, STRING, and Swiss Target Prediction were used. In addition to using CYTOSCAPE software to display and analyze the findings, ShinyGO and FunRich tools were used to identify the gene enrichment analysis to the set of recognized genes. The results detected the identified metabolites were annotated by 254 targets. ALB, ACHE, TYMS, PRKCD, PLG, MMP9, MMP2, ERN1, EDNRA, BRD4 were found to be associated with MRSA infection. The top KEGG pathway was the vascular smooth muscle contraction pathway according to enrichment FDR. The present study suggested a possible implication of P. officinalis roots as a potent candidate having a powerful antibacterial activity against MRSA.

Potentials of Acetylcholinesterase and Butyrylcholinesterase Alterations in On-Pump Coronary Artery Bypass Surgery in Postoperative Delirium: An Observational Trial

Cardiac surgery is regularly associated with postoperative delirium (POD), affected by neuro-inflammation and changes in cholinergic activity. Therefore, this prospective observational study aimed to evaluate whether pre- and perioperative changes in blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity were associated with POD development in patients undergoing isolated elective coronary artery bypass graft (CABG) surgery. It included 93 patients. Pre- and postoperative blood AChE and BChE activities were measured with photometric rapid-point-of-care-testing. The Intensive Care Delirium Screening Checklist and the Confusion Assessment Method for the Intensive Care Unit were used to screen patients for POD. POD developed in 20 patients (21.5%), who were older (p = 0.003), had higher EuroSCOREs (p ≤ 0.001), and had longer intensive care unit stays (p < 0.001). On postoperative day one, BChE activity decreased from preoperative values more in patients with (31.9%) than without (23.7%) POD (group difference p = 0.002). Applying a cutoff of ≥32.0% for BChE activity changes, receiver operating characteristic analysis demonstrated a moderate prediction capability for POD (area under the curve = 0.72, p = 0.002). The risk of developing POD was 4.31 times higher with a BChE activity change of ≥32.0% (p = 0.010). Monitoring the pre- to postoperative reduction in BChE activity might be a clinically practicable biomarker for detecting patients at risk of developing POD after CABG surgery.

Exosomes from bacteria (Streptococcus parauberis) challenged olive flounder (Paralichthys olivaceus): Isolation, molecular characterization, wound healing, and regeneration activities

Exosomes are a group of extracellular vesicles carrying membrane proteins, lipids, RNAs, and, cytosolic proteins, which play key role in intercellular communication and homeostasis. This study describes the isolation, physicochemical, morphological and molecular characterization, toxicity, wound healing, and regeneration properties of plasma derived exosomes from naive (phosphate-buffered saline [PBS]-injected; PBS-Exo) and Streptococcus parauberis-challenged (Sp-Exo) olive flounder (Paralichthys olivaceus). The average diameters of PBS-Exo and Sp-Exo were 120.5 ± 6.1 and 113.1 ± 9.3 nm, respectively, and they presented unique cup shape morphologies. Both exosomes exhibited classical tetraspanin surface markers (CD81, CD9, and CD63) and were enriched with acetylcholinesterase. High-throughput miRNA profiling revealed differentially expressed miRNAs (log₂ fold change ≥1; P < 0.05), including 14 known and 22 novel miRNAs, in Sp-Exo. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that the target genes of the miRNAs contribute towards various physiological and immunological functions, including wound healing and fin regeneration. Sp-Exo exhibited a rapid wound healing (cell migration) capacity in human fibroblast cells, and its mRNA and protein expression patterns corroborated its activity. Higher larval fin regeneration was more prevalent in Sp-Exo than in PBS-Exo, which further confirmed its functional significance. Our study provides the first basic physiochemical, morphometric, molecular (miRNA profiling), and wound healing evidences of Sp-Exo in olive flounder and highlights important miRNA cargoes in exosomes that may be potential therapeutic candidates in wound healing.

Bioactive properties and untargeted metabolomics analysis of bioaccessible fractions of non-fermented and fermented date fruit pomace by novel yeast isolates

In this study, attempts were made to utilize date by-product (date fruit pomace; DFP). This study aimed to investigate the health-promoting benefits of the fermented and non-fermented DFP before in vitro digestion and after (bioaccessible fraction). Untargeted metabolomic analyses for bioaccessible fractions were performed by UPLC-QTOF. DPPH percentages were 89.7%-90.3%, 90.1%-91.3%, and 90.8%-91.3% in the control, I. orientalis, and P. kudriazevii samples, respectively, before digestion; α-glucosidase inhibition before digestion was 1.9%-24.4%, 16.3%-30.0%, and 21.3%-31.3%, respectively; antimicrobial activities were 6.1%-13.3%, 13.7%-25.7%, and 20.6%-28.0% against E. coli O157:H7 and 2.2%-11.9%, 7.2%-20.7%, and 11.9%-29.2% against L. monocytogenes, respectively. The DPPH scavenging percentages were ∼63% lower in the bioaccessible fraction. The differentially regulated metabolites classes were benzene and derivatives, amino acids, peptides and analogs, organic acids, and phenols. This study revealed that the fermented DFP exhibited higher health properties than control.

Paneth Cell Secretion in vivo Requires Expression of Tmem16a and Tmem16f

Background and Aims

Paneth cells play a central role in intestinal innate immune response. These cells are localized at the base of small intestinal crypts of Lieberkuhn. The calcium-activated chloride channel TMEM16A and the phospholipid scramblase TMEM16F control intracellular Ca2+ signaling and exocytosis. We analyzed the role of TMEM16A and TMEM16F for Paneth cells secretion.

Methods

Mice with intestinal epithelial knockout of Tmem16a (Tmem16a-/-) and Tmem16f (Tmem16f-/-) were generated. Tissue structures and Paneth cells were analyzed, and Paneth cell exocytosis was examined in small intestinal organoids in vitro. Intracellular Ca2+ signals were measured and were compared between wild-type and Tmem16 knockout mice. Bacterial colonization and intestinal apoptosis were analyzed.

Results

Paneth cells in the crypts of Lieberkuhn from Tmem16a-/- and Tmem16f-/- mice demonstrated accumulation of lysozyme. Tmem16a and Tmem16f were localized in wild-type Paneth cells but were absent in cells from knockout animals. Paneth cell number and size were enhanced in the crypt base and mucus accumulated in intestinal goblet cells of knockout animals. Granule fusion and exocytosis on cholinergic and purinergic stimulation were examined online. Both were strongly compromised in the absence of Tmem16a or Tmem16f and were also blocked by inhibition of Tmem16a/f. Purinergic Ca2+ signaling was largely inhibited in Tmem16a knockout mice. Jejunal bacterial content was enhanced in knockout mice, whereas cellular apoptosis was inhibited.

Conclusion

The present data demonstrate the role of Tmem16 for exocytosis in Paneth cells. Inhibition or activation of Tmem16a/f is likely to affect microbial content and immune functions present in the small intestine.

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.

Impact of Key Nicotinic AChR Subunits on Post-Stroke Pneumococcal Pneumonia

Pneumonia is the most frequent severe medical complication after stroke. An overactivation of the cholinergic signaling after stroke contributes to immunosuppression and the development of spontaneous pneumonia caused by Gram-negative pathogens. The α7 nicotinic acetylcholine receptor (α7nAChR) has already been identified as an important mediator of the anti-inflammatory pathway after stroke. However, whether the α2, α5 and α9/10 nAChR expressed in the lung also play a role in suppression of pulmonary innate immunity after stroke is unknown. In the present study, we investigate the impact of various nAChRs on aspiration-induced pneumonia after stroke. Therefore, α2, α5, α7 and α9/10 nAChR knockout (KO) mice and wild type (WT) littermates were infected with Streptococcus pneumoniae (S. pneumoniae) three days after middle cerebral artery occlusion (MCAo). One day after infection pathogen clearance, cellularity in lung and spleen, cytokine secretion in bronchoalveolar lavage (BAL) and alveolar-capillary barrier were investigated. Here, we found that deficiency of various nAChRs does not contribute to an enhanced clearance of a Gram-positive pathogen causing post-stroke pneumonia in mice. In conclusion, these findings suggest that a single nAChR is not sufficient to mediate the impaired pulmonary defense against S. pneumoniae after experimental stroke.

Nutritional Regulation of Gut Barrier Integrity in Weaning Piglets

Simple Summary

Weaning is a very stressful period in the piglet’s life in intensive farming: it is a sudden process occurring between three to four weeks of age, when the gastrointestinal tract (GIT) is still immature. The GIT is formed by the epithelial, immune and enteric nervous system which controls epithelial barrier integrity as well as gut functions including the transport of luminal nutrients, water and electrolytes. Early weaning is characterized by a breakdown of these gut functions, an increase in intestinal permeability and the appearance of gastrointestinal functional disorders, which can have long-lasting consequences in the pig’s life. Weaning, therefore, requires the correct level of nutrients, high quality ingredients, and management, which are directed primarily at encouraging rapid feed intake whilst reducing mortality and morbidity. This review describes the organization of the GIT and highlights the interactions between feed components and the morphology and physiology of the epithelial barrier. Novel dietary strategies focused on improving gut health are also discussed, considering the impacts of selected feed ingredients or additives on the GIT such as functional amino acids, phytochemicals and organic acids.

Abstract

Weaning is very stressful for piglets and leads to alterations in the intestinal barrier, a reduction in nutrient absorption and a higher susceptibility to intestinal diseases with heavy economic losses. This review describes the structures involved in the intestinal barrier: the epithelial barrier, immune barrier and the enteric nervous system. Here, new insights into the interactions between feed components and the physiology and morphology of the epithelial barrier are highlighted. Dietary strategies focused on improving gut health are also described including amino acids, phytochemicals and organic acids.

Inhibition of Tyrosine-Phosphorylated STAT3 in Human Breast and Lung Cancer Cells by Manuka Honey is Mediated by Selective Antagonism of the IL-6 Receptor

Aberrantly high levels of tyrosine-phosphorylated signal transducer and activator of transcription 3 (p-STAT3) are found constitutively in ~50% of human lung and breast cancers, acting as an oncogenic transcription factor. We previously demonstrated that Manuka honey (MH) inhibits p-STAT3 in breast cancer cells, but the exact mechanism remained unknown. Herein, we show that MH-mediated inhibition of p-STAT3 in breast (MDA-MB-231) and lung (A549) cancer cell lines is accompanied by decreased levels of gp130 and p-JAK2, two upstream components of the IL-6 receptor (IL-6R) signaling pathway. Using an ELISA-based assay, we demonstrate that MH binds directly to IL-6Rα, significantly inhibiting (~60%) its binding to the IL-6 ligand. Importantly, no evidence of MH binding to two other cytokine receptors, IL-11Rα and IL-8R, was found. Moreover, MH did not alter the levels of tyrosine-phosphorylated or total Src family kinases, which are also constitutively activated in cancer cells, suggesting that signaling via other growth factor receptors is unaffected by MH. Binding of five major MH flavonoids (luteolin, quercetin, galangin, pinocembrin, and chrysin) was also tested, and all but pinocembrin could demonstrably bind IL-6Rα, partially (30-35%) blocking IL-6 binding at the highest concentration (50 μM) used. In agreement, each flavonoid inhibited p-STAT3 in a dose-dependent manner, with estimated IC50 values in the 3.5-70 μM range. Finally, docking analysis confirmed the capacity of each flavonoid to bind in an energetically favorable configuration to IL-6Rα at a site predicted to interfere with ligand binding. Taken together, our findings identify IL-6Rα as a direct target of MH and its flavonoids, highlighting IL-6R blockade as a mechanism for the anti-tumor activity of MH, as well as a viable therapeutic target in IL-6-dependent cancers.

Neuroimmune regulation of lung infection and inflammation

The distal airway of the lung is innervated by vagus nerve. Upon stimulation, vagus nerve endings release acetylcholine or neuropeptides via C-fiber afferents to regulate lung infection and immunity. Vagal sensory nerve endings, brain integration center, acetylcholine and α7 nicotinic acetylcholine receptor (nAChR) expressing cells are key components of pulmonary parasympathetic inflammatory reflex. Meanwhile, this local machinery synergizes with spleen (as a functional hub of cholinergic anti-inflammatory pathway) to finely tune recruitment of the splenic α7 nAChR+CD11b+ cells into the inflamed lungs during lung infection. Recent studies have showed that lung group 2 innate lymphoid cells (ILC2) express both α7 nAChR and neuropeptide receptors. Acetylcholine and neuropeptides can regulate ILC2 and reshape pulmonary infection and immunity. Among the airway epithelial cells, pulmonary neuroendocrine cells are rare cell population; however, these cells are innervated by sensory nerve endings and they could secrete neuropeptides that influence lung infection and immunity.

Involvement of Acetylcholine Receptors in Cholinergic Pathway-Mediated Protection Against Autoimmune Diabetes

Type I diabetes (T1D) is a T cell-driven autoimmune disease that results in the killing of pancreatic β-cells and, consequently, loss of insulin production. Using the multiple low-dose streptozotocin (MLD-STZ) model of experimental autoimmune diabetes, we previously reported that pretreatment with a specific acetylcholinesterase inhibitor (AChEI), paraoxon, prevented the development of hyperglycemia in C57BL/6 mice. This correlated with an inhibition of T cell infiltration into the pancreatic islets and a reduction in pro-inflammatory cytokines. The cholinergic anti-inflammatory pathway utilizes nicotinic and muscarinic acetylcholine receptors (nAChRs and mAChRs, respectively) expressed on a variety of cell types. In this study, we carried out a comparative analysis of the effect of specific antagonists of nAChRs or mAChRs on the development of autoimmune diabetes. Co-administration of mecamylamine, a non-selective antagonist of nAChRs maintained the protective effect of AChEI on the development of hyperglycemia. In contrast, co-administration of atropine, a non-selective antagonist of mAChRs, mitigated AChEI-mediated protection. Mice pretreated with mecamylamine had an improved response in glucose tolerance test (GTT) than mice pretreated with atropine. These differential effects of nAChR and mAChR antagonists correlated with the extent of islet cell infiltration and with the structure and functionality of the β-cells. Taken together, our data suggest that mAChRs are essential for the protective effect of cholinergic stimulation in autoimmune diabetes.

Repurposing Pilocarpine Hydrochloride for Treatment of Candida albicans Infections

Candida albicans is the most common human fungal pathogen with an estimated crude mortality rate of 40%. The ability of the organism to switch from the yeast to hyphal form and produce biofilms are important virulence factors. C. albicans infections are combatted by the host immune system. However, Candida triggers a strong inflammatory response that, if not appropriately regulated, can damage host tissues. Therefore, it is important that the host immune response eliminates the fungus but limits tissue damage. This study provides evidence that targeting cholinergic receptors cannot only curb the virulence of C. albicans by inhibiting filamentous growth and biofilm formation but can also appropriately regulate the host immune response to induce rapid clearance with limited damage to vital tissues. This article provides evidence that repurposing licensed drugs that target cholinergic receptors may offer novel therapeutic solutions for the prevention or treatment of fungal infections.

Acetylcholine modulates the virulence of Candida albicans and regulates an appropriate immune response to infection in a Galleria mellonella infection model. Indeed, the evidence suggests that C. albicans possesses a functional cholinergic receptor that can regulate filamentous growth and biofilm formation. Furthermore, G. mellonella immune cell subsets possess repertories of cholinergic receptors which regulate an effective and appropriate cellular immune response to C. albicans infection. This study aimed to investigate the cholinergic receptor subtype involved in regulation of filamentous growth and biofilm formation by C. albicans and determine the roles of cholinergic receptors in modulation of G. mellonella immune cell subsets. The general muscarinic receptor agonist, pilocarpine hydrochloride, inhibited C. albicans biofilm formation and pathogenicity, a phenomenon that could be reversed using the general muscarinic receptor antagonist, scopolamine. Pilocarpine hydrochloride protected G. mellonella larvae from C. albicans infection via inhibition of C. albicans filamentation and appropriate regulation of cellular immunity. However, scopolamine abrogated the capacity of pilocarpine hydrochloride to protect G. mellonella larvae from C. albicans infection. Furthermore, acetylcholine and pilocarpine hydrochloride exhibited differential modulatory capabilities on Galleria mellonella hemocyte responses to C. albicans. The data in this article demonstrate that a muscarinic receptor modulates C. albicans filamentation and biofilm formation. Furthermore, the results suggest that G. mellonella hemocyte subsets possess unique repertoires of cholinergic receptors that regulate their differentiation, activation, and function in contrasting manners. Therefore, targeting cholinergic receptors by repurposing currently licensed cholinergic drugs may offer novel therapeutic solutions for the prevention or treatment of fungal infections.

IMPORTANCECandida albicans is the most common human fungal pathogen with an estimated crude mortality rate of 40%. The ability of the organism to switch from the yeast to hyphal form and produce biofilms are important virulence factors. C. albicans infections are combatted by the host immune system. However, Candida triggers a strong inflammatory response that, if not appropriately regulated, can damage host tissues. Therefore, it is important that the host immune response eliminates the fungus but limits tissue damage. This study provides evidence that targeting cholinergic receptors cannot only curb the virulence of C. albicans by inhibiting filamentous growth and biofilm formation but can also appropriately regulate the host immune response to induce rapid clearance with limited damage to vital tissues. This article provides evidence that repurposing licensed drugs that target cholinergic receptors may offer novel therapeutic solutions for the prevention or treatment of fungal infections.

S. Typhimurium challenge in juvenile pigs modulates the expression and localization of enteric cholinergic proteins and correlates with mucosal injury and inflammation

The cholinergic system plays a central role in regulating critical gastrointestinal functions, including motility, secretion, barrier and immune function. In rodent models of acute, non-infectious gastrointestinal injury, the cholinergic system functions to inhibit inflammation; however, during inflammation local expression and regulation of the cholinergic system is not well known, particularly during infectious enteritis. The objective of this study was to determine the intrinsic expression of the enteric cholinergic system in pig ileum following an acute challenge with Salmonella enterica serovar Typhimurium DT104 (S. Typhimurium). At 2 d post-challenge, a three-fold reduction in ileal acetylcholine (ACh) levels was observed in challenged animals, compared with controls. Ileal acetylcholinesterase (AChE) activity was decreased (by four-fold) while choline acetyltransferase (ChAT) expression was increased in both the ileum and mesenteric lymph nodes. Elevated ChAT found to localize preferentially to mucosa overlying lymphoid follicles of the Peyers patch in challenged pigs, with more intense labeling for ChAT in S. Typhimurium challenged pigs compared to controls. Ileal mRNA gene expression of muscarinic receptor 1 and 3 was also increased in challenged pigs, while muscarinic receptor 2 and the nicotinic receptor alpha 7 subunit gene expression were unaffected. A positive correlation was observed between ChAT protein expression in the ileum, rectal temperature, and histopathological severity in challenged animals. These data show that inflammation from S. Typhimurium challenge alters enteric cholinergic expression by down-regulating acetylcholine concentration and acetylcholine degrading enzymes while increasing acetylcholine synthesis proteins and receptors. Given the known anti-inflammatory role of the cholinergic system, the divergent expression of cholinergic genes may represent an attempt to limit tissue damage by preserving cholinergic signaling in the face of low ligand availability.

Cholinergic Activation Enhances Resistance to Oral Salmonella Infection by Modulating Innate Immune Defense Mechanisms at the Intestinal Barrier

Inflammation is a crucial defense mechanism that protects the body from the devastating effects of invading pathogens. However, an unrestrained inflammatory reaction may result in systemic manifestations with dire consequences to the host. The extent of activation of the inflammatory response is tightly regulated through immunological and neural pathways. Previously, we demonstrated that cholinergic stimulation confers enhanced protection in experimental animals orally infected with virulent Salmonella enterica serovar Typhimurium. In this study, we investigated the mechanism by which this enhanced protection takes place. Cholinergic stimulation was induced by a 3-week pretreatment with paraoxon, a highly specific acetylcholinesterase (AChE) inhibitor. This treatment enhanced host survival following oral-route infection and this correlated with significantly reduced bacterial load in systemic target organs. Enhanced protection was not due to increased gut motility or rapid bacterial clearance from the gastrointestinal tract. Moreover, protection against bacterial infection was not evident when the animals were infected systemically, suggesting that acetylcholine-mediated protective effect was mostly confined to the gut mucosal tissue. In vivo imaging demonstrated a more localized infection and delay in bacterial dissemination into systemic organs in mice pretreated with paraoxon. Morphological analysis of the small intestine (ileum) showed that AChE inhibition induced the degranulation of goblet cells and Paneth cells, two specialized secretory cells involved in innate immunity. Our findings demonstrate a crucial pathway between neural and immune systems that acts at the mucosal interface to protect the host against oral pathogens.

Weaning stress and gastrointestinal barrier development: Implications for lifelong gut health in pigs

The gastrointestinal (GI) barrier serves a critical role in survival and overall health of animals and humans. Several layers of barrier defense mechanisms are provided by the epithelial, immune and enteric nervous systems. Together they act in concert to control normal gut functions (e.g., digestion, absorption, secretion, immunity, etc.) whereas at the same time provide a barrier from the hostile conditions in the luminal environment. Breakdown of these critical GI functions is a central pathophysiological mechanism in the most serious GI disorders in pigs. This review will focus on the development and functional properties of the GI barrier in pigs and how common early life production stressors, such as weaning, can alter immediate and long-term barrier function and disease susceptibility. Specific stress-related pathophysiological mechanisms responsible for driving GI barrier dysfunction induced by weaning and the implications to animal health and performance will be discussed.

Signals of vagal circuits engaging with AKT1 in α7 nAChR+CD11b+ cells lessen E. coli and LPS-induced acute inflammatory injury

Vagal circuits-α7 nAChR (α7 nicotinic acetylcholine receptor, coded by Chrna7) signaling utilizes spleen as a hub to dampen systemic inflammatory responses. Vagal innervations also extend to the distal airways and alveoli. Vagotomy and deficiency of α7 nAChR deteriorate E. coli and lipopolysaccharide (LPS)-induced acute lung inflammatory responses; however, the underlying mechanisms remain elusive. Here, we hypothesized that vagal circuits would limit splenic release and lung recruitment of α7 nAChR⁺CD11b⁺ cells (CD11b is coded by Itgam, a surface marker of monocytes and neutrophils) via phosphorylation of AKT1 and that this process would define the severity of lung injury. Using both E. coli and LPS-induced lung injury mouse models, we found that vagotomy augmented splenic egress and lung recruitment of α7 nAChR⁺CD11b⁺ cells, and consequently worsened lung inflammatory responses. Rescue of vagotomy with an α7 nAChR agonist preserved α7 nAChR⁺CD11b⁺ cells in the spleen, suppressed recruitment of these cells to the lung and attenuated lung inflammatory responses. Vagal signals via α7 nAChR promoted serine473 phosphorylation of AKT1 in α7 nAChR⁺CD11b⁺ cells and stabilized these cells in the spleen. Deletion of Akt1 enhanced splenic egress and lung recruitment of α7 nAChR⁺CD11b⁺ cells, which elicited neutrophil-infiltrated lung inflammation and injury. Vagotomy and double deletion of Chrna7 and Itgam reduced serine473 phosphorylation of AKT1 in the spleen and BAL (bronchoalveolar lavage) Ly6C^intGr1^hi neutrophils and Ly6C^hi monocytes, and they facilitated the recruitment of neutrophils and monocytes to the airspaces of E. coli-injured lungs. Double deletion of Chrna7 and Itgam increased lung recruitment of monocytes and/or neutrophils and deteriorated E. coli and LPS-induced lung injury. Thus, signals of vagal circuits engaging with AKT1 in α7 nAChR⁺CD11b⁺ cells attenuate E. coli and LPS-induced acute lung inflammatory responses. Targeting this signaling pathway could provide novel therapeutic strategies for treating acute lung injury.

Cholinergic Stimulation Prevents the Development of Autoimmune Diabetes: Evidence for the Modulation of Th17 Effector Cells via an IFNγ-Dependent Mechanism

Type I diabetes (T1D) results from T cell-mediated damage of pancreatic β-cells and loss of insulin production. The cholinergic anti-inflammatory pathway represents a physiological link connecting the central nervous and immune systems via vagus nerve, and functions to control the release of proinflammatory cytokines. Using the multiple low-dose streptozotocin (MLD-STZ) model to induce experimental autoimmune diabetes, we investigated the potential of regulating the development of hyperglycemia through administration of paraoxon, a highly specific acetylcholinesterase inhibitor (AChEI). We demonstrate that pretreatment with paraoxon prevented hyperglycemia in STZ-treated C57BL/6 mice. This correlated with a reduction in T cell infiltration into pancreatic islets and preservation of the structure and functionality of β-cells. Gene expression analysis of pancreatic tissue revealed that increased peripheral cholinergic activity prevented STZ-mediated loss of insulin production, this being associated with a reduction in IL-1β, IL-6, and IL-17 proinflammatory cytokines. Intracellular cytokine analysis in splenic T cells demonstrated that inhibition of AChE led to a shift in STZ-induced immune response from a predominantly disease-causing IL-17-expressing Th17 cells to IFNγ-positive Th1 cells. Consistent with this conclusion, inhibition of AChE failed to prevent STZ-induced hyperglycemia in IFNγ-deficient mice. Our results provide mechanistic evidence for the prevention of murine T1D by inhibition of AChE and suggest a promising strategy for modulating disease severity.

Hepatic cholinesterase of laying hens naturally infected by Salmonella Gallinarum (fowl typhoid)

Salmonella is a facultative intracellular pathogen that may cause foodborne gastroenteritis in humans and animals consisting of over 2000 serovars. The serovar Salmonella Gallinarum is an important worldwide pathogen of poultry. However, little is known on the mechanisms of pathogenesis of Salmonella in chickens. The aim of this study was to evaluate cholinesterase and myeloperoxidase activities in hepatic tissue of laying hens naturally infected by S. Gallinarum. Twenty positive liver samples for S. Gallinarum were collected, in addition to seven liver samples from healthy uninfected laying hens (control group). The right liver lobe was homogenized for analysis of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and myeloperoxidase (MPO), and the left lobe was divided into two fragments, one for histopathology and the other for Salmonella isolation. The results showed changes in AChE and BchE activity in the liver of infected laying hens compared to the control group (P < 0.05), i.e. reduced AChE and increased BChE activities in liver samples. Infected animals showed increased MPO activity compared to healthy animals (P < 0.05). Furthermore, the histopathological findings showed fibrinoid necrosis associated to the infiltration of lymphocytes, plasma cells, macrophages,heterophils in the liver of infected hens. These findings suggest that the inflammatory process was attenuated providing a pro-inflammatory action of both enzyme analyzed in order to reduce the free ACh, a molecule which has an anti-inflammatory action. Therefore, our results lead to the hypothesis that cholinesterase plays an important role on the modulation of immune response against S. Gallinarum with an inflammatory effect, contributing to the response against this bacterium. This study should contribute to a better understanding on the pathogenic mechanisms involved in laying hens infected by S. Gallinarum.

The M3 muscarinic receptor is required for optimal adaptive immunity to helminth and bacterial infection

Innate immunity is regulated by cholinergic signalling through nicotinic acetylcholine receptors. We show here that signalling through the M3 muscarinic acetylcholine receptor (M3R) plays an important role in adaptive immunity to both Nippostrongylus brasiliensis and Salmonella enterica serovar Typhimurium, as M3R-/- mice were impaired in their ability to resolve infection with either pathogen. CD4 T cell activation and cytokine production were reduced in M3R-/- mice. Immunity to secondary infection with N. brasiliensis was severely impaired, with reduced cytokine responses in M3R-/- mice accompanied by lower numbers of mucus-producing goblet cells and alternatively activated macrophages in the lungs. Ex vivo lymphocyte stimulation of cells from intact BALB/c mice infected with N. brasiliensis and S. typhimurium with muscarinic agonists resulted in enhanced production of IL-13 and IFN-γ respectively, which was blocked by an M3R-selective antagonist. Our data therefore indicate that cholinergic signalling via the M3R is essential for optimal Th1 and Th2 adaptive immunity to infection.

Caffeine intake may modulate inflammation markers in trained rats

Caffeine is presented in many commercial products and has been proven to induce ergogenic effects in exercise, mainly related to redox status homeostasis, inflammation and oxidative stress-related adaptation mechanisms. However, most studies have mainly focused on muscle adaptations, and the role of caffeine in different tissues during exercise training has not been fully described. The aim of this study was therefore, to analyze the effects of chronic caffeine intake and exercise training on liver mitochondria functioning and plasma inflammation markers. Rats were divided into control, control/caffeine, exercise, and exercise/caffeine groups. Exercise groups underwent four weeks of swimming training and caffeine groups were supplemented with 6 mg/kg/day. Liver mitochondrial swelling and complex I activity, and plasma myeloperoxidase (MPO) and acetylcholinesterase (AChE) activities were measured. An anti-inflammatory effect of exercise was evidenced by reduced plasma MPO activity. Additionally, caffeine intake alone and combined with exercise decreased the plasma AChE and MPO activities. The per se anti-inflammatory effect of caffeine intake should be highlighted considering its widespread use as an ergogenic aid. Therefore, caffeine seems to interfere on exercise-induced adaptations and could also be used in different exercise-related health treatments.

Perinatal exposure to insecticide methamidophos suppressed production of proinflammatory cytokines responding to virus infection in lung tissues in mice

Methamidophos, a representative organophosphate insecticide, is regulated because of its severe neurotoxicity, but it is suspected of contaminating agricultural foods in many countries due to illicit use. To reveal unknown effects of methamidophos on human health, we evaluated the developmental immunotoxicity of methamidophos using a respiratory syncytial virus (RSV) infection mouse model. Pregnant mice were exposed to methamidophos (10 or 20 ppm) in their drinking water from gestation day 10 to weaning on postnatal day 21. Offsprings born to these dams were intranasally infected with RSV. The levels of interleukin-6 (IL-6) and interferon-gamma in the bronchoalveolar lavage fluids after infection were significantly decreased in offspring mice exposed to methamidophos. Treatment with methamidophos did not affect the pulmonary viral titers but suppressed moderately the inflammation of lung tissues of RSV-infected offspring, histopathologically. DNA microarray analysis revealed that gene expression of the cytokines in the lungs of offspring mice exposed to 20 ppm of methamidophos was apparently suppressed compared with the control. Methamidophos did not suppress IL-6 production in RSV-infected J774.1 cell cultures. Thus, exposure of the mother to methamidophos during pregnancy and nursing was suggested to cause an irregular immune response in the lung tissues in the offspring mice.

The cholinergic system and inflammation: common pathways in delirium pathophysiology

OBJECTIVES

To investigate whether delirium is associated with an unbalanced inflammatory response or a dysfunctional interaction between the cholinergic and immune systems.

DESIGN

Cohort observational study.

SETTING

General hospital orthopedic ward.

PARTICIPANTS

One hundred one individuals aged 60 and older with no previous cognitive impairment undergoing elective arthroplasty.

MEASUREMENTS

Incidence of postoperative delirium, plasma cholinesterase activity (acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)) and inflammatory mediators (C-reactive protein (CRP), interleukin (IL)-1 beta, tumor necrosis factor alpha, IL-6, IL-8, IL-10) before and after surgery.

RESULTS

Thirty-seven participants developed postoperative delirium and had greater production of CRP and proinflammatory to anti-inflammatory ratio after surgery. In participants with delirium, but not in controls, preoperative levels of plasma cholinesterase activity correlated with ΔCRP (AChE: ρ = 0.428, P = .008 and BuChE: ρ = 0.423, P = .009), ΔIL-6 (AChE: ρ = 0.339, P = .04), and ΔP/A ratio (AChE: ρ = 0.346, P = .04).

CONCLUSION

Delirium was associated not only with an unbalanced inflammatory response, but also with a dysfunctional interaction between the cholinergic and immune systems. Comprehensive understanding of the relationship between the cholinergic and immune systems is crucial to developing new insights into delirium pathophysiology and novel therapeutic interventions.