Search Results (495)

Plasticity is fundamental to the development, strengthening, and maintenance of healthy synaptic connections and recovery from injury in both the central and peripheral nervous systems. Yet, the processes involved are poorly understood. Herein, using a combination of patch-clamp electrophysiology and immuno-fluorescence confocal microscopy in adult mice, it is shown that blockade of synaptic transmission at submandibular ganglion junctions exposed to botulinum neurotoxin type A was accompanied by a rapid and striking decline in the abundance of synaptic vesicle markers—SV2, vesicle-associated membrane protein 2, and vesicular acetylcholine transporter—plus SNAP-25 (cleaved and intact) and postsynaptic α7 nicotinic acetylcholine receptors. Such alterations by the neurotoxin of parasympathetic synapses contrast starkly with the stability of postsynaptic proteins at nearby skeletal neuromuscular junctions. Both neurotransmission and the expression of SV2 and α7 nicotinic acetylcholine receptors remained depressed for 4 weeks, with full recovery of synaptic function delayed for more than 8 weeks. These novel findings may explain the relatively slow recovery of autonomic function after botulism or following therapeutic injections to alleviate hypersecretory disorders. Full article

Fibroblast growth factor 21 (FGF21) is a key hormone for metabolic homeostasis under conditions such as obesity, aging and diabetes. While extensively studied in males, its role in female physiology remains poorly defined. This study evaluated the effects of hepatic FGF21 deletion in 12-month-old female mice using a liver-specific FGF21 knockout (FKO) model. FKO females exhibited reduced body weight and improved glucose tolerance, with no changes in circulating FGF21 levels. In the liver, RT-qPCR analysis showed that the expression of genes involved in de novo lipogenesis, including Srebp1c, Fasn, and Scd1, was downregulated, whereas markers of fatty acid uptake (Cd36) and β-oxidation (Cpt1a) were upregulated without alterations in hepatic triglyceride content and lower levels of serum adiponectin. Remarkably, telomere length in both liver and adipose tissue was preserved, indicating improved cellular aging. Hepatic transcriptomic analysis revealed a global downregulation of genes linked to cytoskeletal organization, immune processes and fibrosis. Among these, Chrna4, a hepatocyte-specific nicotinic acetylcholine receptor subunit implicated in protection against metabolic-associated steatohepatitis (MASH), was significantly reduced. These findings suggest that hepatic FGF21 deficiency in aged female mice promotes metabolic health by limiting pro-inflammatory and fibrotic pathways and preserving telomere integrity, with Chrna4 emerging as a potential mediator. Full article

Recently, we found that Lystar5 protein from coelomic cells of A. rubens starfish interacts with nicotinic acetylcholine receptors (nAChRs) and integrin α8-like protein. We hypothesized that Lystar5 mediates detachment of coelomic cells from the matrix and their migration. Skin wound healing in humans is based on keratinocytes migration and is regulated by nAChRs and integrins. Here, we revealed that Lystar5 stimulates migration of human skin HaCaT keratinocytes and peripheral blood monocytes. Using ELISA, we found that Lystar5 binds to the membrane fraction of coelomic cells with its loops I and II, which form an active site of Lystar5 and resemble its pro-migratory activity. In keratinocytes and monocytes, Lystar5 and the peptides mimicking its loops I and II bound with α3, α4, and β2 nAChR and α5, αV, and β1 integrin subunits, which form molecular complexes. In keratinocytes, Lystar5 and its mimetics promoted short-term E/N cadherin switch and upregulated expression of α5 and αV integrins, EGFR, and ICAM-1. In keratinocytes and monocytes, Lystar5 and its mimetics upregulated E-selectin secretion. The ability of Lystar5 and its mimetics to stimulate skin keratinocyte migration and immune cell infiltration may be considered promising for the development of new wound-healing agents. Full article

Magnesium ions regulate synaptic and nonsynaptic neuronal excitability from intracellular (Mg²⁺_i) and extracellular (Mg²⁺_o) domains, modulating voltage- and ligand-gated ion channels. K+ inward rectifier (Kir) channel inward rectification arises from Mg²⁺_i blocking the pore and outward K⁺ current, while Mg²⁺_o targets external sites. Mg²⁺_i causes voltage-dependent Ca²⁺ voltage-gated (Ca_V) and Na⁺ voltage-gated (Na_V) channel block while phosphorylation modulates channel activity. Mg²⁺_o elicits direct voltage-dependent Ca_V channel block, and screens surface charge, and in Na_V channels reduces conduction and may cause depolarization by quantum tunneling across closed channels. Mg²⁺_i is an allosteric large conductance Ca²⁺-activated K⁺ (BK) channel activator, binding to low-affinity sites to alter Ca²⁺ and voltage sensitivity but reduces small conductance Ca²⁺-activated K⁺ (SK) channels’ outward K⁺ current and induces inward rectification. N-Methyl-D-aspartate receptor (NMDAR) channels are inhibited by Mg²⁺_i binding within the pore, while Mg²⁺_o stabilizes excitability through voltage-dependent block, Mg²⁺_o forms Mg-ATP complex modifying purinergic P2X receptor (P2XR) channel affinity and gating and directly blocks the pore. Mg²⁺_o reduces gamma-aminobutyric acid type A receptor (GABA_AR) channel Cl⁻ current amplitude and augments susceptibility to blockers. Mg²⁺_o and Mg²⁺_i block nicotinic acetylcholine receptor (nAChR) channels through voltage-dependent pore binding and surface charge screening, impeding current flow and altering gating. Full article

White-matter development during fetal life represents one of the most vulnerable processes to environmental disruption, as it relies on the precisely timed proliferation, migration, and differentiation of oligodendrocyte lineage cells. Among environmental threats, exposure to toxic compounds contained in tobacco smoke and vaping aerosols represents a major yet preventable risk during pregnancy. Despite growing awareness, tobacco smoking remains widespread, and a substantial proportion of the population—including pregnant women—continues to perceive electronic nicotine delivery systems (ENDS) as less harmful, a misconception that contributes to persistent prenatal exposure. These products expose the fetus to numerous substances that readily cross the placenta and reach the developing brain, including compounds with endocrine-disrupting activity, where they interfere with white-matter development. Epidemiological and neuroimaging studies consistently reveal microstructural alterations in white matter that correlate with long-term cognitive and behavioral impairments in offspring exposed in utero. These alterations may arise from both nicotine-specific pathways and the actions of other toxicants in cigarette smoke and ENDS aerosols that cross the placenta and disrupt white-matter emergence and maturation. Preclinical research provides mechanistic insight: nicotine acts directly on nicotinic acetylcholine receptors (nAChRs) in oligodendrocyte precursor cells, disrupting calcium signaling and differentiation, while additional constituents of smoke and vaping aerosols also affect astrocyte and microglial function and disturb the extracellular milieu required for proper myelination. Full article

Parkinson’s disease (PD) involves motor and cognitive impairment that nicotinic acetylcholine receptors (nAChRs) such as the α7 subtype are responsible for regulating. The hippocampus, abundant in α7 nAChRs, was quantitatively evaluated for [¹²⁵I]α-bungarotoxin ([¹²⁵I]α-Bgtx) binding to α7 nAChRs in postmortem human PD (n = 26; 12 male, 14 female) and cognitively normal (CN) (n = 29; 14 male, 15 female) brain slices. Anti-ubiquitin and anti-α-synuclein immunostained adjacent slices were analyzed using QuPath. Autoradiographs of [¹²⁵I]α-Bgtx radioligand binding were analyzed in OptiQuant. Ubiquitin and α-synuclein distribution generally aligned with the distribution of α7 nAChRs detected by [¹²⁵I]α-Bgtx. Binding of [¹²⁵I]α-Bgtx in PD cases was significantly greater than CN with a 32% increase in gray matter binding. A weak positive correlation between age and [¹²⁵I]α-Bgtx binding was found in both PD and CN. In comparison to Alzheimer’s disease hippocampus, [¹²⁵I]α-Bgtx binding in PD gray matter was higher by 41%. Differences in nAChR expression imply unique roles depending on the neurodegenerative pathology. PD may experience an increase in α7 nAChRs as a compensatory mechanism to the loss in neurons, highlighting its neuroprotective capabilities. [¹²⁵I]α-Bgtx shows potential as a radioligand for α7 nAChRs to elucidate the complexities of PD pathology. Full article

Teleost fish are the first evolutionary group to exhibit an innate and adaptive immune system. Within the mechanisms of adaptive immunity, fish possess, among others, T-helper cells (CD4-like) and their differentiation machinery, regulated by the master transcription factors T-bet, GATA3, Foxp3, and RORγ. Many studies support the existence of a non-neuronal cholinergic system involved in the immune response, named after the ability of leukocytes to synthesize de novo acetylcholine (ACh). Organophosphorus pesticides (OPs), such as diazoxon (DXN), are examples of compounds that act as cholinergic disruptors with immunotoxic effects. The present study aimed to evaluate the expression of transcription factors in leukocytes (spleen mononuclear cells, SMNCs) of Nile tilapia by modulating cholinergic pathways in immune cells using agonists, antagonists, and diazoxon (DXN), an anticholinesterase substance. The obtained data showed a significant increase in RORγ mRNA expression upon stimulation with the nicotinic agonist, whereas activation of the muscarinic receptor with its agonist increased T-bet mRNA expression. An alteration in RORγ expression levels induced by DXN exposure was also observed. The results suggest a probable directing of the immune response towards a pro-inflammatory profile orchestrated mainly by RORγ and T-bet transcription factors in response to cholinergic stimuli. Full article

Sulfoxaflor, an insecticide, acts on nicotinic acetylcholine receptors. It has a functional group similar to that of neonicotinoid insecticides, which are testicular toxicants. Recently, the adverse effects of sulfoxaflor on the testes have been reported in rats. This study aimed to address the lack of reports on sulfoxaflor administration in mice and its effects on the testes. ICR mice (3- and 10-week-old) were treated ad libitum with two different concentrations (10 and 100 mg/kg) of sulfoxaflor for 4 and 8 weeks. Histological analysis and real-time reverse transcription polymerase chain reaction were performed. Testis weights relative to body weights in the sulfoxaflor groups showed no significant difference compared to the control group. Testicular tissue in the sulfoxaflor groups was unchanged compared to that in the control group. The sulfoxaflor-treated group showed no significant differences in the mRNA expression of luteinizing hormone and follicle-stimulating hormone in the pituitary gland compared to the control group. Furthermore, no significant differences were noted in the mRNA expression levels of various gene markers in the testes between the sulfoxaflor-treated and control groups. These markers include those related to Leydig cells, testosterone synthesis, Sertoli cells, proliferating cells, meiotic cells, pachytene spermatocytes, round spermatids, apoptotic cells, antioxidant enzymes, oxidative stress factors, and mitochondrial function. In contrast to findings in rats, which showed testicular toxicity, sulfoxaflor administration at low concentrations did not adversely affect intratesticular cells in either mature or immature mice at the doses and time points examined. In the future, we would like to conduct research on high concentrations of sulfoxaflor by changing the administration method. Full article

Background: Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder with limited treatment options. Emerging evidence reveals bidirectional crosstalk between gut and brain through inflammatory signaling, leading us to hypothesize that anti-neuroinflammatory agents may concurrently ameliorate intestinal inflammation. The scorpion venom-derived heat-resistant synthetic peptide (SVHRSP), a bioactive peptide initially identified in scorpion venom and subsequently synthesized by our laboratory, possesses neuroprotective, anti-inflammatory, and antioxidative activities. Its properties make SVHRSP a promising candidate for investigating the therapeutic potential of anti-neuroinflammatory strategies in mitigating intestinal inflammation. Methods: Using a chronic dextran sodium sulfate (DSS)-induced colitis model in wild-type and α7 nicotinic acetylcholine receptor (α7nAChR) knockout mice, along with lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, we assessed SVHRSP’s effects on inflammation, histopathology, gut permeability, oxidative stress markers, and α7nAChR-Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling. Results: SVHRSP treatment significantly ameliorated colitis symptoms in wild-type mice by reducing inflammation, repairing histological damage, restoring gut barrier function, and attenuating oxidative stress, with these effects abolished in α7nAChR knockout mice. Mechanistically, SVHRSP activated JAK2/STAT3 signaling through α7nAChR engagement, suppressing proinflammatory cytokine production in macrophages. Conclusion: These results demonstrated that SVHRSP alleviated intestinal inflammation via α7nAChR-dependent JAK2/STAT3 activation. Combined with its known neuroprotective properties, our findings support the repurposing of this neuroactive peptide, SVHRSP, for treating intestinal inflammatory disorders. Full article

Neonicotinoid pesticides, including imidacloprid (IMI), are widely used in agriculture and as household insecticides. IMI displays strong affinity for insect nicotinic acetylcholine receptors (nAChRs); however, neonicotinoids still partially bind to mammalian nAChRs. Relatively little is known about how neonicotinoid exposure alters learning, memory or mood, even though nAChRs play a role in these mechanisms. We tested the hypothesis that developmental exposure to IMI impairs performance on memory tasks, and anxiety- and depressive-like behavior. We orally dosed pregnant CD-1 mice from gestation day 10 to birth with vehicle or IMI at 0.5 mg/kg/day or 5.7 mg/kg/day. When exposed animals were adults, we examined cognitive and emotional behaviors and we examined the effect of IMI on α7 and α4 nAChR subunit mRNA expression using qPCR. For both sexes, IMI exposure was associated with impaired striatal-dependent procedural learning task and hippocampal-dependent spatial learning but had no effect on hippocampal-dependent working memory. Males, but not females, displayed increased anxiety-like behavior, with low dose subjects displaying more pronounced effects, suggesting a non-linear dose response. In males, we found lower α7 subunit mRNA expression in the hippocampus and amygdala and lower α4 mRNA expression in the striatum compared to controls. Thus, exposure to IMI during a critical period is associated with disruptions to cognitive and anxiety-like behaviors. Additionally, in males, IMI exposure is associated with reduced expression of nAChR subunits in relevant brain regions. Full article

The cholinergic system is one of the most ancient and widespread signaling systems in the body, implicated in a range of pathological conditions—from neurodegenerative disorders to cancer. Given its broad relevance, there is growing interest in characterizing this system across diverse cellular models to enable drug screening, mechanistic studies, and exploration of new therapeutic avenues. In this study, we investigated four cancer cell lines: one of neuroblastoma origin previously used in cholinergic signaling studies (SH-SY5Y), one non-small cell lung adenocarcinoma line (A549), and two small cell lung carcinoma lines (H69 and H82). We assessed the expression and localization of key components of the cholinergic system, along with the cellular capacity for acetylcholine (ACh) synthesis and release. Whole-cell flow cytometry following membrane permeabilization revealed that all cell lines expressed the ACh-synthesizing enzyme choline acetyltransferase (ChAT). HPLC-MS analysis confirmed that ChAT was functionally active, as all cell lines synthesized and released ACh into the conditioned media, suggesting the presence of autocrine and/or paracrine ACh signaling circuits, consistent with previous reports. The cell lines also demonstrated choline uptake, indicative of functional choline and/or organic cation transporters. Additionally, all lines expressed the ACh-degrading enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), as well as the alfa seven (α7) nicotinic and M1 muscarinic ACh receptor subtypes. Notably, flow cytometry of intact SH-SY5Y cells revealed two novel findings: (1) ChAT was localized to the extracellular membrane, a feature not observed in the lung cancer cell lines, and (2) BChE, rather than AChE, was the predominant membrane-bound ACh-degrading enzyme. These results were corroborated by both whole-cell and surface-confocal microscopy. In conclusion, our findings suggest that a functional cholinergic phenotype is a shared feature of several carcinoma cell lines, potentially serving as a survival checkpoint that could be therapeutically explored. The discovery of extracellular membrane-bound ChAT uniquely in neuroblastoma SH-SY5Y cells points to a novel form of in situ ACh signaling that warrants further investigation. Full article

Besides its neurotoxic action and selective toxicity on insecticidal nicotinic acetylcholine receptors, recent studies have shown that imidacloprid may cause other adverse effects in mammals. In the present study, cholinesterase activity, oxidative stress response, genotoxicity in the liver and kidney, and imidacloprid levels in the urine, liver, and kidney of male Wistar rats orally administered with 0.06, 0.8, and 2.25 mg imidacloprid/kg bw/day for 28 days were evaluated. Imidacloprid urine mass concentrations in treated rats increased dose-dependently. Exposure to 0.8 mg imidacloprid/kg bw/per day significantly decreased cholinesterase activities in the liver and kidney. Reactive oxygen species levels decreased significantly in the liver at the same dose. Lipid peroxidation was significantly reduced in the liver at two higher doses. No significant changes in glutathione levels or the activities of superoxide dismutase and catalase were observed. A significant decrease in the activity of glutathione peroxidase was detected in the liver at the highest dose. DNA damage was low in both liver and kidney. Exposure to imidacloprid at studied experimental conditions did not cause a significant oxidative stress response and resulted in low genotoxic effects in the liver and kidney of rats, indicating that these organs are less susceptible to adverse imidacloprid effects at such low doses. Full article

Autosomal-dominant sleep-related hypermotor epilepsy (ADSHE) was the first distinct genetic epilepsy proven to be caused by mutation of the CHRNA4 gene, originally reported in 1994. In the past three decades, pathomechanisms of ADSHE associated with mutant nicotinic acetylcholine receptors (nAChRs) have been explored via various studies, including in vitro experiments and genetic rodent models. However, findings emphasize that functional abnormalities of ADSHE-mutant nAChRs alone cannot generate ictogenesis; rather, development of abnormalities in various other transmission systems induced by ADSHE-mutant nAChRs during the neurodevelopmental process before the ADSHE onset is involved in development of epileptogenesis/ictogenesis. Intra-thalamic GABAergic disinhibition induced by loss-of-function of S284L-mutant nAChRs (S286L-mutant nAChRs in rat ADSHE models) contributes to enhancing propagation of physiological ripple-burst high-frequency oscillation (HFO) and Erk signaling during sleep, leading to enhancement of the trafficking of pannexin1, connexin43, and P2X7 purinergic receptor to the astroglial plasma membrane. The combination of activation of physiological ripple-HFO and upregulation of astroglial hemichannels under the GABAergic disinhibition plays an important role in generation of epileptogenic fast-ripple-HFO during sleep. Therefore, loss-of-function of the S284L-mutation alone cannot drive ictogenesis but contributes to the development of epileptogenesis as an initial abnormality. Based on these recent findings using genetic rat ADSHE models, harboring the rat S286L-mutant Chrna4 corresponding to the human S284L-mutant CHRNA4, this report proposes hypothetical pathomechanisms of ADSHE. Full article

Cytisine, a naturally occurring alkaloid and partial agonist of nicotinic acetylcholine receptors (nAChRs), has long been used as a smoking cessation aid and serves as the pharmacophore for varenicline. Recent research has expanded its therapeutic scope to neurodegenerative and neurological disorders, motivating the development of new cytisine derivatives. Among these, N-propargylcytisine combines the biological activity of the parent compound with the synthetic versatility of the terminal alkyne group. Herein, we report the synthesis and characterization of N-propargylcytisine, and its symmetrical dimer linked through 1,3-diyne moiety obtained via a copper-mediated Glaser–Hay oxidative coupling. The products were analyzed by NMR, FT-IR, and mass spectrometry, confirming the introduction of the propargyl moiety and the formation of the diyne bridge. Solvatochromic study of both compounds were performed using UV-VIS absorption spectroscopy in solvents of varying polarity, including protic solvents capable of hydrogen bonding. The 1,3-diyne motif, commonly found in bioactive natural products, endows the resulting dimer with potential for further derivatization and biological evaluation. This study demonstrates the utility of the Glaser–Hay reaction in the functionalization of alkaloid scaffolds and highlights the prospects of N-propargylcytisine derivatives in drug discovery targeting the central nervous system. Full article

Marine sources contain compounds that act on a wide variety of systems, including ligand-gated ion channels. This review will focus on the effectors of nicotinic acetylcholine receptors (nAChRs), for which the diversity of ligands and modulators from marine sources is determined mainly by neurotoxic peptides (α-conotoxins) from mollusks of the Conus genus. These are very selective compounds that allow the study of the role of different nAChR subtypes in the cancer cells. They have analgesic or anti-inflammatory activities associated with cholinergic transmission and have shown analgesic effect in case of chemotherapy-induced neuropathic pain. Another class of marine compounds targeting nAChRs for which cytotoxicity for cancer cells was shown is represented by low molecular organic substances found mostly in dinoflagellates and marine sponges. Some of the compounds discussed in this review show promise for developing drugs that suppress cancer growth. Full article