GTS-21 ameliorates polymicrobial sepsis-induced hepatic injury by modulating autophagy through α7nAchRs in mice

Exploring the Potential Role of the Cholinergic Anti-Inflammatory Pathway from the Perspective of Sepsis Pathophysiology

Sepsis is one of the most prevalent conditions in critical care medicine and is characterized by a high incidence, mortality, and poor prognosis, with no specific treatment currently available. The pathogenesis of sepsis is complex with a dysregulated inflammatory response at its core. If the initial inflammatory response is not promptly controlled, patients often develop multiple organ dysfunction syndrome or die, whereas survivors may experience post-sepsis syndrome. Regulation by the central and autonomic nervous systems is essential for maintaining inflammatory homeostasis. Among these, the cholinergic anti-inflammatory pathway (CAP) has been extensively studied in sepsis owing to its significant role in modulating inflammatory responses. Recent advancements in CAP-related interventions include minimally invasive vagus nerve stimulation, novel α7nAchR-targeting drugs, serum choline acetyltransferase and cholinesterase, acupuncture, and focused ultrasound stimulation therapy. This review primarily discusses the advantages, limitations, and therapeutic prospects of these approaches. Additionally, heart rate variability, which reflects changes in autonomic nervous system function, can serve as an indicator for assessing the functional status of the vagus nerve. In summary, modulation of inflammatory responses through the vagus nerve-mediated CAP represents a potential strategy for achieving precision medicine for sepsis. Future research should focus on conducting high-quality clinical studies on CAP-based therapies in the context of sepsis-induced inflammatory dysregulation. Incorporating indicators to evaluate the autonomic nervous system function may further elucidate the impact of inflammatory dysregulation in the body.

Macrophage Polarization: Learning to Manage It 3.0

Macrophages are cells of the innate immune system with very peculiar characteristics, so plastic that they respond rapidly to environmental changes by assuming different and sometimes contrasting functions, such as initiating a physiological inflammatory response or interrupting it and repairing damaged tissues [...].

Brain-Gut Axis: Invasive and Noninvasive Vagus Nerve Stimulation, Limitations, and Potential Therapeutic Approaches

Inflammatory bowel disease (IBD) is a chronic relapsing condition with no known etiology and is characterized by disrupted gut homeostasis, chronic inflammation, and ulcerative lesions. Although current treatments can reduce disease activity, IBD frequently recurs once treatments are discontinued, indicating that treatments are ineffective in providing long-term remission. The lack of responsiveness and reluctance of some affected persons to take medications because of potential adverse effects has enhanced the need for novel therapeutic approaches. The vagus nerve (VN) is likely important in the pathogenesis of IBD, considering the decreased activity of the parasympathetic nervous system, especially the VN, and the impaired interaction between the enteric nervous system and central nervous system in patients with IBD. Vagus nerve stimulation (VNS) has demonstrated anti-inflammatory effects in various inflammatory disorders, including IBD, by inhibiting the production of inflammatory cytokines by immune cells. It has been suggested that stimulating the vagus nerve to induce its anti-inflammatory effects may be a potential therapeutic approach for IBD. Noninvasive techniques for VNS have been developed. Considering the importance of VN function in the brain-gut axis, VNS is a promising treatment option for IBD. This review discusses the potential therapeutic advantages and drawbacks of VNS, particularly the use of noninvasive transcutaneous auricular vagus nerve stimulation.

Manipulation of the inflammatory reflex as a therapeutic strategy

The cholinergic anti-inflammatory pathway is the efferent arm of the inflammatory reflex, a neural circuit through which the CNS can modulate peripheral immune responses. Signals communicated via the vagus and splenic nerves use acetylcholine, produced by Choline acetyltransferase (ChAT)+ T cells, to downregulate the inflammatory actions of macrophages expressing α7 nicotinic receptors. Pre-clinical studies using transgenic animals, cholinergic agonists, vagotomy, and vagus nerve stimulation have demonstrated this pathway's role and therapeutic potential in numerous inflammatory diseases. In this review, we summarize what is understood about the inflammatory reflex. We also demonstrate how pre-clinical findings are being translated into promising clinical trials, and we draw particular attention to innovative bioelectronic methods of harnessing the cholinergic anti-inflammatory pathway for clinical use.

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 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.

Application of marine natural products in drug research

New diseases are emerging as the environment changes, so drug manufacturers are always on the lookout for new resources to develop effective and safe drugs. In recent years, many bioactive substances have been produced in the marine environment, which represents an alternative resource for new drugs used to combat major diseases such as cancer or inflammation. Many marine-derived medicinal substances are in preclinical or early stage of clinical development, and some marine drugs have been put on the market, such as ET743 (Yondelis®). This review presents the sources, activities, mechanisms of action and syntheses of bioactive substances based on marine natural products in clinical trials and on the market, which is helpful to understand the progress of drug research by application of marine natural products.

Cardioprotective role of GTS-21 by attenuating the TLR4/NF-κB pathway in streptozotocin-induced diabetic cardiomyopathy in rats

The cholinergic anti-inflammatory pathway (CAP) was investigated in a variety of inflammatory conditions and constitutes a valuable line in their treatment. In the current study, we investigated the anti-inflammatory effect of GTS-21 (GTS) as a partial selective α7 nicotinic acetylcholine receptor (α7-nAchR) agonist in diabetic cardiomyopathy model in rats. This mechanism was elaborated to study whether it could alleviate the electrocardiographic, histopathological, and molecular levels of Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway proteins. Diabetes was induced by the injection of streptozotocin (STZ) (50 mg/kg). Diabetic rats were treated with GTS (1 or 2 mg/kg/day), methyllycaconitine (MLA), a selective α7-nAchR antagonist (2 mg/kg/day) plus GTS (2 mg/kg/day), or the vehicle. All treatments were given by the intraperitoneal route. Ventricular rate and different electrocardiograph (ECG) anomalies were detected. Plasma levels of cardiac troponin T (cTnT) and creatine kinase MB (CK-MB) were measured by ELISA. Additionally, we elucidated the levels of several proteins involved in the TLR4/NF-κB pathway. Cardiac levels of TLR4 and phosphorylated protein kinase B (p-Akt) were detected by ELISA. The cardiac expression of myeloid differentiation primary response 88 (Myd88), tumor necrosis factor receptor-associated factor 6 (TRAF6), NF-κB, interleukin 1β (IL-1β), and active caspase-1 were evaluated by immunohistochemical staining. Finally, the cardiac levels of interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. Diabetic rats showed (i) ECG signs of cardiomyopathy such as significant ST segment elevations, prolonged QRS, QT intervals, and ventricular tachycardia; (ii) increased plasma levels of cTnT and CK-MB; (iii) increased expression of cardiac TLR4; (iv) elevated immunohistochemical expression of cardiac, Myd88, TRAF6, and NF-κB; (v) diminution in the cardiac expression of p-Akt; and (vi) adaptive increases in cardiac expression of TNF-α and IL-6. These effects were ameliorated in diabetic rats treated with both doses of GTS. Pretreatment with MLA did not completely reverse the ameliorative effect of GTS on cTnT, TRAF6, TNF-α, and IL-6, thereby reinforcing the presence of possible α7-nAchR-independent mechanisms. The activation of α7-nAchR with GTS offers a promising prophylactic strategy for diabetic cardiomyopathy by attenuating the TLR4/NF-κB pathway.

Metabolomic Analysis of the Effects of Adipose-Derived Mesenchymal Stem Cell Treatment on Rats With Sepsis-Induced Acute Lung Injury

Given the high mortality associated with sepsis, there is an urgent need for a full understanding of sepsis pathophysiology and finding new therapeutic regimens. Adipose-derived mesenchymal stem cells (ADMSCs) has been proven to have anti-inflammatory effects and could be used to treat cecal ligation and puncture (CLP) induced lung and liver injury in septic rat models. In this study, we used metabolomics to investigate small molecule metabolites between CLP and ADMSCs treatment groups. Sixty SD rats were randomly assigned to the sham operation group (SC group), the CLP group, and the CLP+ADMSCs group (CLP-ADMSCs group). We used liquid mass spectrometry-chromatography to detect metabolic changes in plasma and lung tissues. Compared with the SC group, the metabolic profile of plasma and lung tissues changed significantly 24 h after CLP. Moreover, 22 and 11 main differential metabolites involved in amino acid and glycerophospholipid metabolism were found in plasma and lung tissues, respectively. After the rats were injected with ADMSCs, these differential metabolites were reverse-regulated both in plasma and lung tissues. Besides, ADMSCs improved the survival rate and down-regulated the concentration of TNF-α and IL-6 at 24 h after CLP. The correlational analysis between plasma of IL-6/TNF-α and metabolites suggested that acetylcholine, spermine, phenylalanine, threonine of plasma and phosphatidylcholine (36:4) of lung tissues were significantly associated with IL-6/TNF-α in CLP and CLP-ADMSCs groups. ADMSCs might reverse abnormal metabolic pathways by reducing anti-inflammatory factors in sepsis-induced ALI. Our findings may provide novel metabolic mechanism of ADMSCs therapy for sepsis.