ABSTRACT
Nicotine intake is linked to the maintenance and development of anxiety disorders and impairs adaptive discrimination of threat and safety in rodents and humans. Yet, it is unclear if nicotine exerts a causal pharmacological effect on the affective and neural mechanisms that underlie aversive learning. We conducted a pre-registered, pseudo-randomly and double-blinded pharmacological fMRI study to investigate the effect of acute nicotine on Fear Acquisition and Extinction in non-smokers (n = 88). Our results show that nicotine administration led to decreased discrimination between threat and safety in subjective fear. Nicotine furthermore decreased differential (threat vs. safety) activation in the hippocampus, which was functionally coupled with Nucleus Accumbens and amygdala, compared to placebo controls. Additionally, nicotine led to enhanced physiological arousal to learned threats and overactivation of the ventral tegmental area. This study provides mechanistic evidence that single doses of nicotine impair neural substrates of adaptive aversive learning in line with the risk for the development of pathological anxiety.
Subject(s)
Amygdala , Fear , Hippocampus , Magnetic Resonance Imaging , Nicotine , Nucleus Accumbens , Humans , Nicotine/pharmacology , Nicotine/adverse effects , Nicotine/administration & dosage , Nucleus Accumbens/drug effects , Nucleus Accumbens/diagnostic imaging , Male , Hippocampus/drug effects , Fear/drug effects , Adult , Amygdala/drug effects , Amygdala/diagnostic imaging , Female , Young Adult , Double-Blind Method , Discrimination, Psychological/drug effects , Nicotinic Agonists/pharmacology , Nicotinic Agonists/adverse effects , Nicotinic Agonists/administration & dosage , Extinction, Psychological/drug effectsABSTRACT
Social controllability, or the ability to exert control during social interactions, is crucial for optimal decision-making. Inability to do so might contribute to maladaptive behaviors such as smoking, which often takes place in social settings. Here, we examined social controllability in nicotine-dependent humans as they performed an fMRI task where they could influence the offers made by simulated partners. Computational modeling revealed that smokers under-estimated the influence of their actions and self-reported a reduced sense of control, compared to non-smokers. These findings were replicated in a large independent sample of participants recruited online. Neurally, smokers showed reduced tracking of forward projected choice values in the ventromedial prefrontal cortex, and impaired computation of social prediction errors in the midbrain. These results demonstrate that smokers were less accurate in estimating their personal influence when the social environment calls for control, providing a neurocomputational account for the social cognitive deficits in this population. Pre-registrations: OSF Registries|How interoceptive state interacts with value-based decision-making in addiction (fMRI study). OSF Registries|COVID-19: social cognition, mental health, and social distancing (online study).
Subject(s)
Magnetic Resonance Imaging , Tobacco Use Disorder , Humans , Male , Female , Adult , Tobacco Use Disorder/physiopathology , Tobacco Use Disorder/psychology , Decision Making , COVID-19/psychology , Prefrontal Cortex/physiopathology , Prefrontal Cortex/diagnostic imaging , Prefrontal Cortex/physiology , Middle Aged , Young Adult , Social Interaction , Social Cognition , Nicotine/adverse effects , Nicotine/pharmacologyABSTRACT
Prolonged exposure to different occupational or environmental toxicants triggered oxidative stress and inflammatory reactions mediated lung damage. This study was designed to explore the influence and protective impact of flavone on lung injury in rats intoxicated with nicotine (NIC) and exposed to radiation (IR). Forty rats were divided into four groups; group I control, group II flavone; rats were administered with flavone (25 mg/kg/day), group III NIC + IR; rats were injected intraperitoneally with NIC (1 mg/kg/day) and exposed to γ-IR (3.5 Gy once/week for 2 weeks) while group IV NIC + IR + flavone; rats were injected with NIC, exposed to IR and administered with flavone. Redox status parameters and histopathological changes in lung tissue were evaluated. Nuclear factor-kappa B (NF-κB), forkhead box O-class1 (FoxO1) and nucleotide-binding domain- (NOD-) like receptor pyrin domain-containing-3 (NLRP3) gene expression were measured in lung tissues. Moreover, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and phosphatidylinositol three kinase (PI3K) were measured using ELISA kits. Our data demonstrates, for the first time, that flavone protects the lung from NIC/IR-associated cytotoxicity, by attenuating the disrupted redox status and aggravating the antioxidant defence mechanism via activation of the PI3K/Nrf2. Moreover, flavone alleviates pulmonary inflammation by inhibiting the inflammatory signaling pathway FOXO1/NF-κB/NLRP3- Inflammasome. Collectively, the obtained results exhibited a notable efficiency of flavone in alleviating lung injury induced by NIC and IR via modulating PI3K/Nrf2 and FoxO1/NLRP3 Inflammasome.
Subject(s)
Flavones , Inflammasomes , Lung Injury , Nicotine , Animals , Male , Rats , Flavones/pharmacology , Forkhead Box Protein O1 , Gamma Rays , Inflammasomes/metabolism , Inflammasomes/drug effects , Lung/drug effects , Lung/metabolism , Lung/pathology , Lung/radiation effects , Lung Injury/metabolism , Lung Injury/prevention & control , NF-E2-Related Factor 2/metabolism , NF-kappa B/metabolism , Nicotine/pharmacology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Oxidative Stress/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Rats, Wistar , Signal Transduction/drug effectsABSTRACT
Nicotine is developmentally toxic. Prenatal nicotine exposure (PNE) affects the development of multiple fetal organs and causes susceptibility to a variety of diseases in offspring. In this study, we aimed to investigate the effect of PNE on cartilage development and osteoarthritis susceptibility in female offspring rats. Wistar rats were orally gavaged with nicotine on days 9-20 of pregnancy. The articular cartilage was obtained at gestational day (GD) 20 and postnatal week (PW) 24, respectively. Further, the effect of nicotine on chondrogenic differentiation was explored by the chondrogenic differentiation model in human Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs). The PNE group showed significantly shallower Safranin O staining and lower Collagen 2a1 content of articular cartilage in female offspring rats. Further, we found that PNE activated pyroptosis in the articular cartilage at GD20 and PW24. In vitro experiments revealed that nicotine inhibited chondrogenic differentiation and activated pyroptosis. After interfering with nod-like receptors3 (NLRP3) expression by SiRNA, it was found that pyroptosis mediated the chondrogenic differentiation inhibition of WJ-MSCs induced by nicotine. In addition, we found that α7-nAChR antagonist α-BTX reversed nicotine-induced NLRP3 and P300 high expression. And, P300 SiRNA reversed the increase of NLRP3 mRNA expression and histone acetylation level in its promoter region induced by nicotine. In conclusion, PNE caused chondrodysplasia and poor articular cartilage quality in female offspring rats. PNE increased the histone acetylation level of NLRP3 promoter region by α7-nAChR/P300, which resulting in the high expression of NLRP3. Further, NLRP3 mediated the inhibition of chondrogenic differentiation by activating pyroptosis.
Subject(s)
Cartilage, Articular , Mesenchymal Stem Cells , NLR Family, Pyrin Domain-Containing 3 Protein , Nicotine , Prenatal Exposure Delayed Effects , Pyroptosis , Rats, Wistar , alpha7 Nicotinic Acetylcholine Receptor , Animals , Nicotine/pharmacology , Nicotine/toxicity , Female , Cartilage, Articular/drug effects , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pregnancy , Pyroptosis/drug effects , Rats , alpha7 Nicotinic Acetylcholine Receptor/metabolism , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/cytology , Prenatal Exposure Delayed Effects/metabolism , Prenatal Exposure Delayed Effects/chemically induced , Prenatal Exposure Delayed Effects/pathology , Chondrogenesis/drug effects , Cell Differentiation/drug effects , Humans , Chondrocytes/drug effects , Chondrocytes/metabolism , Chondrocytes/cytologyABSTRACT
Nutrition and resilience are linked, though it is not yet clear how diet confers stress resistance or the breadth of stressors that it can protect against. We have previously shown that transiently restricting an essential amino acid can protect Drosophila melanogaster against nicotine poisoning. Here, we sought to characterize the nature of this dietary-mediated protection and determine whether it was sex, amino acid and/or nicotine specific. When we compared between sexes, we found that isoleucine deprivation increases female, but not male, nicotine resistance. Surprisingly, we found that this protection afforded to females was not replicated by dietary protein restriction and was instead specific to individual amino acid restriction. To understand whether these beneficial effects of diet were specific to nicotine or were generalizable across stressors, we pre-treated flies with amino acid restriction diets and exposed them to other types of stress. We found that some of the diets that protected against nicotine also protected against oxidative and starvation stress, and improved survival following cold shock. Interestingly, we found that a diet lacking isoleucine was the only diet to protect against all these stressors. These data point to isoleucine as a critical determinant of robustness in the face of environmental challenges.
Subject(s)
Drosophila melanogaster , Nicotine , Stress, Physiological , Animals , Drosophila melanogaster/drug effects , Female , Male , Nicotine/pharmacology , Stress, Physiological/drug effects , Oxidative Stress/drug effects , Amino Acids/pharmacology , Amino Acids/metabolism , Isoleucine/pharmacologyABSTRACT
The addictive use of nicotine contained in tobacco is associated with stressor-like emotional and cognitive effects such as anxiety and working memory impairment, and the involvement of epigenetic mechanisms such as histone acetylation has recently been reported. Although the precise nature of behavioural plasticity remains unclear, both anxiogenic- and working memory impairment-like effects were observed in the present experimental model of mice treated with repeated subcutaneous nicotine and/or immobilization stress, and these effects were commonly attenuated by the histone deacetylase (HDAC) inhibitors that induce histone acetylation. Such HDAC inhibitor-induced resilience was mimicked by ligands for the endocannabinoid (ECB) system, a neurotransmitter system that is closely associated with nicotine-induced addiction-related behaviours: the anxiogenic-like effects were mitigated by the cannabinoid type 1 (CB1) agonist arachidonylcyclopropylamide (ACPA), whereas the working memory impairment-like effects were mitigated by the CB1 antagonist SR 141716A. Moreover, the effects of the HDAC inhibitors were also mimicked by ligands for the endovanilloid (transient receptor potential vanilloid 1 [TRPV1]) system, a system that shares common characteristics with the ECB system: the anxiogenic-like effects were mitigated by the TRPV1 antagonist capsazepine, whereas the working memory impairment-like effects were mitigated by the TRPV1 agonist olvanil. Notably, the HDAC inhibitor-induced anxiolytic-like effects were attenuated by SR 141716A, which were further counteracted by capsazepine, whereas the working memory improvement-like effects were attenuated by capsazepine, which were further counteracted by SR 141716A. These results suggest the contribution of interrelated control of the ECB/TRPV1 systems and epigenetic processes such as histone acetylation to novel therapeutic approaches.
Subject(s)
Anxiety , Endocannabinoids , Epigenesis, Genetic , Memory, Short-Term , Nicotine , Stress, Psychological , TRPV Cation Channels , Animals , TRPV Cation Channels/drug effects , Nicotine/pharmacology , Mice , Memory, Short-Term/drug effects , Endocannabinoids/metabolism , Male , Epigenesis, Genetic/drug effects , Histone Deacetylase Inhibitors/pharmacology , Receptor, Cannabinoid, CB1/drug effects , Memory Disorders/chemically induced , Capsaicin/pharmacology , Capsaicin/analogs & derivatives , Disease Models, Animal , Rimonabant/pharmacology , Nicotinic Agonists/pharmacology , Piperidines/pharmacologyABSTRACT
Psychoactive substances, including morphine and methamphetamine, have been shown to interact with the classic innate immune receptor Toll-like receptor 4 (TLR4) and its partner protein myeloid differentiation protein 2 (MD2) in a nonenantioselective manner. (-)-Nicotine, the primary alkaloid in tobacco and a key component of highly addictive cigarettes, targets the TLR4/MD2, influencing TLR4 signaling pathways. Existing as two enantiomers, the stereoselective recognition of nicotine by TLR4/MD2 in the context of the innate immune response remains unclear. In this study, we synthesized (+)-nicotine and investigated its effects alongside (-)-nicotine on lipopolysaccharide (LPS)-induced TLR4 signaling. (-)-Nicotine dose-dependently inhibited proinflammatory factors such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and cyclooxygenase-2 (COX-2). In contrast, (+)-nicotine showed no such inhibitory effects. Molecular dynamics simulations revealed that (-)-nicotine exhibited a stronger affinity with the TLR4 coreceptor MD2 than (+)-nicotine. Additionally, in silico simulations revealed that both nicotine enantiomers initially attach to the entrance of the MD2 cavity, creating a metastable state before they fully enter the cavity. In the metastable state, (-)-nicotine established more stable interactions with the surrounding residues at the entrance of the MD2 cavity compared to those of (+)-nicotine. This highlights the crucial role of the MD2 cavity entrance in the chiral recognition of nicotine. These findings provide valuable insights into the distinct interactions between nicotine enantiomers and the TLR4 coreceptor MD2, underscoring the enantioselective effect of nicotine on modulating TLR4 signaling.
Subject(s)
Lymphocyte Antigen 96 , Molecular Dynamics Simulation , Nicotine , Signal Transduction , Toll-Like Receptor 4 , Toll-Like Receptor 4/metabolism , Nicotine/pharmacology , Nicotine/chemistry , Nicotine/analogs & derivatives , Nicotine/metabolism , Lymphocyte Antigen 96/metabolism , Lymphocyte Antigen 96/chemistry , Signal Transduction/drug effects , Stereoisomerism , Humans , Lipopolysaccharides/pharmacology , Molecular Docking Simulation , Cyclooxygenase 2/metabolism , Cyclooxygenase 2/chemistryABSTRACT
Given the pivotal role of neuronal populations in various biological processes, assessing their collective output is crucial for understanding the nervous system's complex functions. Building on our prior development of a spiral scanning mechanism for the rapid acquisition of Raman spectra from single cells and incorporating machine learning for label-free evaluation of cell states, we investigated whether the Paint Raman Express Spectroscopy System (PRESS) can assess neuronal activities. We tested this hypothesis by examining the chemical responses of glutamatergic neurons as individual neurons and autonomic neuron ganglia as neuronal populations derived from human-induced pluripotent stem cells. The PRESS successfully acquired Raman spectra from both individual neurons and ganglia within a few seconds, achieving a signal-to-noise ratio sufficient for detailed analysis. To evaluate the ligand responsiveness of the induced neurons and ganglia, the Raman spectra were subjected to principal component and partial least squares discriminant analyses. The PRESS detected neuronal activity in response to glutamate and nicotine, which were absent in the absence of calcium. Additionally, the PRESS induced dose-dependent neuronal activity changes. These findings underscore the capability of the PRESS to assess individual neuronal activity and elucidate neuronal population dynamics and pharmacological responses, heralding new opportunities for drug discovery and regenerative medicine advancement.
Subject(s)
Glutamic Acid , Induced Pluripotent Stem Cells , Neurons , Spectrum Analysis, Raman , Spectrum Analysis, Raman/methods , Neurons/metabolism , Neurons/physiology , Humans , Induced Pluripotent Stem Cells/cytology , Induced Pluripotent Stem Cells/metabolism , Nicotine/pharmacology , Principal Component AnalysisABSTRACT
Smoking remains a significant health problem in patients with type 2 diabetes mellitus. This study compared intracellular Ca2+ ([Ca2+]i) in microglia, neurons, and astrocytes in the presence of high glucose (HG) and nicotine and evaluated the effects of Lavandula angustifolia Mill. essential oil (LEO) on this process. [Ca2+]i concentrations were measured by monitoring the fluorescence of Fura-2 acetoxymethyl ester. Treatment with HG and nicotine significantly increased [Ca2+]i in both microglia and neurons through Ca2+ influx from extracellular sources. This increased Ca2+ influx in microglia, however, was significantly reduced by LEO, an effect partially inhibited by the Na+/Ca2+ exchanger (NCX) inhibitor Ni2+. Ca2+ influx in neuron-like cells pretreated with HG plus nicotine was also significantly decreased by LEO, an effect partially inhibited by the L-type Ca2+ channel blocker nifedipine and the T-type Ca2+ channel blocker mibefradil. LEO or a two-fold increase in the applied number of astrocytes attenuated Ca2+ influx caused by high glucose and nicotine in the mixed cells of the microglia, neuron-like cells and astrocytes. These findings suggest that LEO can regulate HG and nicotine-induced Ca2+ influx into microglia and neurons through two distinct mechanisms.
Subject(s)
Calcium , Glucose , Lavandula , Microglia , Neurons , Nicotine , Nicotine/pharmacology , Glucose/metabolism , Microglia/drug effects , Microglia/metabolism , Calcium/metabolism , Animals , Neurons/drug effects , Neurons/metabolism , Oils, Volatile/pharmacology , Astrocytes/drug effects , Astrocytes/metabolism , Rats , Calcium Channel Blockers/pharmacology , Cells, CulturedABSTRACT
Adolescence is characterized by a critical period of maturation and growth, during which regions of the brain are vulnerable to long-lasting cognitive disturbances. Adolescent exposure to nicotine can lead to deleterious neurological and psychological outcomes. Moreover, the nicotinic acetylcholine receptor (nAChR) has been shown to play a functionally distinct role in the development of the adolescent brain. CHRNA2 encodes for the α2 subunit of nicotinic acetylcholine receptors associated with CA1 oriens lacunosum moleculare GABAergic interneurons and is associated with learning and memory. Previously, we found that adolescent male hypersensitive CHRNA2L9'S/L9' mice had impairments in learning and memory during a pre-exposure-dependent contextual fear conditioning task that could be rescued by low-dose nicotine exposure. In this study, we assessed learning and memory in female adolescent hypersensitive CHRNA2L9'S/L9' mice exposed to saline or a subthreshold dose of nicotine using a hippocampus-dependent task of pre-exposure-dependent contextual fear conditioning. We found that nicotine-treated wild-type female mice had significantly greater improvements in learning and memory than both saline-treated wild-type mice and nicotine-treated CHRNA2L9'S/L9' female mice. Thus, hyperexcitability of CHRNA2 in female adolescent mice ablated the nicotine-mediated potentiation of learning and memory seen in wild-types. Our results indicate that nicotine exposure during adolescence mediates sexually dimorphic patterns of learning and memory, with wild-type female adolescents being more susceptible to the effects of sub-threshold nicotine exposure. To understand the mechanism underlying sexually dimorphic behavior between hyperexcitable CHRNA2 mice, it is critical that further research be conducted.
Subject(s)
Fear , Hippocampus , Memory , Nicotine , Receptors, Nicotinic , Animals , Receptors, Nicotinic/metabolism , Nicotine/pharmacology , Female , Mice , Hippocampus/drug effects , Hippocampus/metabolism , Fear/drug effects , Fear/physiology , Memory/drug effects , Memory/physiology , Nicotinic Agonists/pharmacology , Learning/drug effects , Learning/physiology , Conditioning, Classical/drug effects , Conditioning, Classical/physiology , Mice, Inbred C57BLABSTRACT
BACKGROUND The effects of cigarette smoking on the health of active smokers and passive smokers have long been known, in contrast to the effects of alternative forms of nicotine intake that are gaining popularity. The aim of the study was to assess the effects of smoking traditional cigarettes and alternative forms of nicotine intake on the functional state of the respiratory system of smokers and non-smokers. MATERIAL AND METHODS Study participants (n=60) were divided into 3 groups: non-smokers (control group), cigarette smokers, and nicotine alternative users. Respiratory function testing (spirometry), forced oscillation technique, and measurement of respiratory muscle strength (PImax, PEmax) were performed. All of the above respiratory function tests were performed in accordance with European Respiratory Society and American Thoracic Society recommendations. RESULTS Smokers and those using alternative forms of nicotine intake had significantly higher values, including resistance at 5 Hz% and 11 Hz%, among others. CONCLUSIONS Smokers and users of alternative forms of nicotine are characterized by reduced flow through the small bronchioles, as evidenced by a reduction in maximal expiratory flow at 25% of vital capacity. Smokers and users of alternative forms of nicotine have higher resistance values at the height of small and medium bronchioles. Assessment method of technical forced oscillation parameters is simple to perform to detect early airway changes and is an important element in the early diagnosis of changes in smokers. The correlation analysis showed a significant correlation between age of smoking initiation/use of alternative forms of nicotine and changes in mid bronchial resistance.
Subject(s)
Respiratory Function Tests , Smoking , Tobacco Products , Humans , Male , Adult , Female , Respiratory Function Tests/methods , Smoking/adverse effects , Nicotine/adverse effects , Nicotine/pharmacology , Middle Aged , Smokers , Spirometry/methodsABSTRACT
Abuse-related drug usage is a public health issue. Drosophila melanogaster has been used as an animal model to study the biological effects of these psychoactive substances in preclinical studies. Our objective in this review is to evaluate the adverse effects produced by cocaine, nicotine, and marijuana during the development of D. melanogaster. We searched experimental studies in which D. melanogaster was exposed to these three psychoactive drugs in seven online databases up to January 2023. Two reviewers independently extracted the data. Fifty-one studies met eligibility criteria and were included in the data extraction: nicotine (n = 26), cocaine (n = 20), and marijuana (n = 5). Fifteen studies were eligible for meta-analysis. Low doses (â¼0.6 mM) of nicotine increased locomotor activity in fruit flies, while high doses (≥3 mM) led to a decrease. Similarly, exposure to cocaine increased locomotor activity, resulting in decreased climbing response in D. melanogaster. Studies with exposure to marijuana did not present a profile for our meta-analysis. However, this drug has been less associated with locomotor changes, but alterations in body weight and fat content and changes in cardiac function. Our analyses have shown that fruit flies exposed to drugs of abuse during different developmental stages, such as larvae and adults, exhibit molecular, morphological, behavioral, and survival changes that are dependent on the dosage. These phenotypes resemble the adverse effects of psychoactive substances in clinical medicine.
Subject(s)
Cocaine , Drosophila melanogaster , Nicotine , Animals , Drosophila melanogaster/drug effects , Cocaine/pharmacology , Cocaine/adverse effects , Nicotine/pharmacology , Nicotine/adverse effects , Locomotion/drug effects , Cannabis/adverse effectsABSTRACT
This study demonstrates the potential of gelatin nanoparticles as a nanodelivery system for antagonists of nicotinic acetylcholine receptors (nAChRs) to improve chemotherapy efficacy and reduce off-target effects. Too often, chemotherapy for lung cancer does not lead to satisfactory results. Therefore, new approaches directed at multiple pharmacological targets in cancer therapy are being developed. Following the activation of nAChRs (e.g. by nicotine), cancer cells begin to proliferate and become more resistant to chemotherapy-induced apoptosis. This work shows that the 3-alkylpyridinium salt, APS7, a synthetic analog of a toxin from the marine sponge Haliclona (Rhizoneira) sarai, acts as an nAChR antagonist that inhibits the pro-proliferative and anti-apoptotic effects of nicotine on A549 human lung adenocarcinoma cells. In this study, gelatin-based nanoparticles filled with APS7 (APS7-GNPs) were prepared and their effects on A549 cells were compared with that of free APS7. Both APS7 and APS7-GNPs inhibited Ca2+ influx and increased the efficacy of cisplatin chemotherapy in nicotine-stimulated A549 cells. However, significant benefits from APS7-GNPs were observed - a stronger reduction in the proliferation of A549 lung cancer cells and a much higher selectivity in cytotoxicity towards cancer cells compared with non-tumorigenic lung epithelial BEAS-2B cells.
Subject(s)
Cell Proliferation , Gelatin , Lung Neoplasms , Nanoparticles , Humans , Gelatin/chemistry , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Lung Neoplasms/metabolism , A549 Cells , Nanoparticles/chemistry , Cell Proliferation/drug effects , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Pyridinium Compounds/pharmacology , Pyridinium Compounds/chemistry , Cisplatin/pharmacology , Nicotine/pharmacology , Nicotinic Antagonists/pharmacology , Nicotinic Antagonists/chemistry , Cell Line, TumorABSTRACT
Infertility is intricately linked with alterations in circadian rhythms along with physiological decline and stem cell senescence. Yet, the direct involvement of circadian mechanisms in nicotine-induced injury to the testes, especially the senescence of spermatogonia stem cells (SSCs), is not well comprehended. This study revealed that nicotine exposure induced testis injury by triggering SSCs senescence along with the upregulation of senescence marker genes and senescence-associated secretory phenotype components. Moreover, nicotine treatment caused mitochondrial hyper-fusion, increased oxidative stress, and DNA damage. Exposure to nicotine was found to suppress the expression of sirtuin 6 (SIRT6), which accelerated the senescence of spermatogonia stem cells (SSCs). This acceleration led to increased acetylation of brain and muscle ARNT-like protein (Bmal1), consequently reducing the expression of Bmal1 protein. Conversely, the overexpression of Bmal1 alleviated mitochondrial hyper-fusion and senescence phenotypes induced by nicotine. Overall, this study unveiled a novel molecular mechanism behind nicotine-induced disorders in spermatogenesis and highlighted the SIRT6/Bmal1 regulatory pathway as a potential therapeutic target for combating nicotine-associated infertility.
Subject(s)
ARNTL Transcription Factors , Cellular Senescence , Circadian Rhythm , Mitochondrial Dynamics , Nicotine , Sirtuins , Sirtuins/metabolism , Sirtuins/genetics , Male , Animals , Nicotine/pharmacology , Nicotine/adverse effects , Cellular Senescence/drug effects , Circadian Rhythm/drug effects , Mitochondrial Dynamics/drug effects , Mice , ARNTL Transcription Factors/metabolism , ARNTL Transcription Factors/genetics , Spermatogonia/drug effects , Spermatogonia/metabolism , Homeostasis/drug effects , Mice, Inbred C57BL , Mitochondria/drug effects , Mitochondria/metabolism , Oxidative Stress/drug effects , Spermatogenesis/drug effects , Signal Transduction/drug effects , Adult Germline Stem Cells/metabolism , Adult Germline Stem Cells/drug effectsABSTRACT
Nicotine has been shown to enhance object recognition memory in the novel object recognition (NOR) test by activating excitatory neurons in the medial prefrontal cortex (mPFC). However, the exact neuronal mechanisms underlying the nicotine-induced activation of mPFC neurons and the resultant memory enhancement remain poorly understood. To address this issue, we performed brain-slice electrophysiology and the NOR test in male C57BL/6J mice. Whole-cell patch-clamp recordings from layer V pyramidal neurons in the mPFC revealed that nicotine augments the summation of evoked excitatory postsynaptic potentials (eEPSPs) and that this effect was suppressed by N-[3,5-Bis(trifluoromethyl)phenyl]-N'-[2,4-dibromo-6-(2H-tetrazol-5-yl)phenyl]urea (NS5806), a voltage-dependent potassium (Kv) 4.3 channel activator. In line with these findings, intra-mPFC infusion of NS5806 suppressed systemically administered nicotine-induced memory enhancement in the NOR test. Additionally, miRNA-mediated knockdown of Kv4.3 channels in mPFC pyramidal neurons enhanced object recognition memory. Furthermore, inhibition of A-type Kv channels by intra-mPFC infusion of 4-aminopyridine was found to enhance object recognition memory, while this effect was abrogated by prior intra-mPFC NS5806 infusion. These results suggest that nicotine augments the summation of eEPSPs via the inhibition of Kv4.3 channels in mPFC layer V pyramidal neurons, resulting in the enhancement of object recognition memory.
Subject(s)
Mice, Inbred C57BL , Nicotine , Prefrontal Cortex , Recognition, Psychology , Animals , Male , Prefrontal Cortex/drug effects , Prefrontal Cortex/physiology , Prefrontal Cortex/metabolism , Nicotine/pharmacology , Mice , Recognition, Psychology/drug effects , Shal Potassium Channels/metabolism , Pyramidal Cells/drug effects , Pyramidal Cells/physiology , Memory/drug effects , Excitatory Postsynaptic Potentials/drug effectsABSTRACT
Nicotine, a key constituent of tobacco/electronic cigarettes causes cardiovascular injury and mortality. Nicotine is known to induce oxidative stress and mitochondrial dysfunction in cardiomyocytes leading to cell death. However, the underlying mechanisms remain unclear. Pleckstrin homology domain leucine-rich repeat protein phosphatase (PHLPP) is a member of metal-dependent protein phosphatase (PPM) family and is known to dephosphorylate several AGC family kinases and thereby regulate a diverse set of cellular functions including cell growth, survival, and death. Our lab has previously demonstrated that PHLPP1 removal reduced cardiomyocyte death and cardiac dysfunction following injury. Here, we present a novel finding that nicotine exposure significantly increased PHLPP1 protein expression in the adolescent rodent heart. Building upon our in vivo finding, we determined the mechanism of PHLPP1 expression in cardiomyocytes. Nicotine significantly increased PHLPP1 protein expression without altering PHLPP2 in cardiomyocytes. In cardiomyocytes, nicotine significantly increased NADPH oxidase 4 (NOX4), which coincided with increased reactive oxygen species (ROS) and increased cardiomyocyte apoptosis which were dependent on PHLPP1 expression. PHLPP1 expression was both necessary and sufficient for nicotine induced mitochondrial dysfunction. Mechanistically, nicotine activated extracellular signal-regulated protein kinases (ERK1/2) and subsequent eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) to increase PHLPP1 protein expression. Inhibition of protein synthesis with cycloheximide (CHX) and 4EGI-1 abolished nicotine induced PHLPP1 protein expression. Moreover, inhibition of ERK1/2 activity by U0126 significantly blocked nicotine induced PHLPP1 expression. Overall, this study reveals a novel mechanism by which nicotine regulates PHLPP1 expression through ERK-4E-BP1 signaling axis to drive cardiomyocyte injury.
Subject(s)
Myocytes, Cardiac , Nicotine , Oxidative Stress , Phosphoprotein Phosphatases , Animals , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/drug effects , Phosphoprotein Phosphatases/metabolism , Phosphoprotein Phosphatases/genetics , Nicotine/pharmacology , Nicotine/adverse effects , Oxidative Stress/drug effects , Nuclear Proteins/metabolism , Nuclear Proteins/genetics , Reactive Oxygen Species/metabolism , Apoptosis/drug effects , Rats , Signal Transduction/drug effects , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Cell Cycle Proteins/metabolism , Cell Cycle Proteins/genetics , MAP Kinase Signaling System/drug effects , NADPH Oxidase 4/metabolism , NADPH Oxidase 4/genetics , Rats, Sprague-Dawley , Mice , Extracellular Signal-Regulated MAP Kinases/metabolism , MaleABSTRACT
OBJECTIVE: The sympathetic-parasympathetic (or axo-axonal) interaction mechanism mediated that neurogenic relaxation, which was dependent on norepinephrine (NE) releases from sympathetic nerve terminal and acts on ß2-adrenoceptor of parasympathetic nerve terminal, has been reported. As NE is a weak ß2-adrenoceptor agonist, there is a possibility that synaptic NE is converted to epinephrine by phenylethanolamine-N-methyltransferase (PNMT) and then acts on the ß2-adrenoceptors to induce neurogenic vasodilation. METHODS: Blood vessel myography technique was used to measure relaxation and contraction responses of isolated basilar arterial rings of rats. RESULTS: Nicotine-induced relaxation was sensitive to propranolol, guanethidine (an adrenergic neuronal blocker), and Nω-nitro-l-arginine. Nicotine- and exogenous NE-induced vasorelaxation was partially inhibited by LY-78335 (a PNMT inhibitor), and transmural nerve stimulation depolarized the nitrergic nerve terminal directly and was not inhibited by LY-78335; it then induced the release of nitric oxide (NO). Epinephrine-induced vasorelaxation was not affected by LY-78335. However, these vasorelaxations were completely inhibited by atenolol (a ß1-adrenoceptor antagonist) combined with ICI-118,551 (a ß2-adrenoceptor antagonist). CONCLUSIONS: These results suggest that NE may be methylated by PNMT to form epinephrine and cause the release of NO and vasodilation. These results provide further evidence supporting the physiological significance of the axo-axonal interaction mechanism in regulating brainstem vascular tone.
Subject(s)
Nicotine , Phenylethanolamine N-Methyltransferase , Vasodilation , Animals , Vasodilation/drug effects , Phenylethanolamine N-Methyltransferase/metabolism , Rats , Nicotine/pharmacology , Male , Norepinephrine/pharmacology , Cerebral Arteries/drug effects , Nitric Oxide/metabolism , Rats, Sprague-Dawley , Receptors, Adrenergic, beta-2/metabolism , Epinephrine/pharmacologyABSTRACT
Chronic obstructive pulmonary disease (COPD) is an inflammatory lung condition associated with cigarette (tobacco) smoking. Numerous in vivo animal studies have been conducted to investigate the links between cigarette smoke, nicotine and infection in lung pathology. As an alternative to animal experiments, we used an in vitro system to investigate the effects of cigarette smoke extract (CSE) or nicotine on TNF-α and IL-10 production by monocyte-derived human macrophages. The macrophages were simultaneously stimulated with either poly-IC (as a chemical surrogate for viral infection) or lipopolysaccharide (as a chemical surrogate for Gram-negative bacterial infection). CSE enhanced TNF-α production, whereas nicotine inhibited IL-10 production by the macrophages, particularly when co-stimulated with the microbial chemical surrogates. A system of this type may help to further our understanding of the immunological and inflammatory effects of smoking, without recourse to in vivo studies. Requirements for the optimisation and standardisation of such an in vitro system are also discussed.
Subject(s)
Macrophages , Nicotine , Humans , Nicotine/pharmacology , Nicotine/toxicity , Macrophages/drug effects , Macrophages/metabolism , Cytokines/metabolism , Smoke/adverse effects , Lipopolysaccharides/pharmacology , Nicotiana , Tumor Necrosis Factor-alpha/metabolism , Interleukin-10/metabolism , Tobacco Products , Poly I-C/pharmacology , Cells, Cultured , Toll-Like Receptors/metabolismABSTRACT
OBJECTIVES: The primary objective of this in vitro experiment was an assessment of proliferative capacity, metabolic activity, and potential cellular detriment of human periodontal ligament cells (hPDL) exposed to cigarette smoke (CS), electronic cigarette vapor (eCV), and heated tobacco product aerosol (HTP), or air (control). MATERIALS AND METHODS: Using a CAD/CAM-designed exposition chamber, hPDL were exposed to CS, eCV, HTP, or air (control) based on the Health Canada Intense Smoking Regime. Cell proliferation, metabolic activity, and cellular detriment were assessed at various time points. RESULTS: Compared to the control, hPDL exposed to CS exhibited significantly decreased cell numbers at all time points. HTP exposure led to reduced cell numbers 48 h and 72 h post-exposure, while eCV-exposed cells showed no significant decrease. The metabolic activity of eCV-treated hPDL was slightly reduced at 7 h but recovered at 24 h and 48 h. In contrast, CS-treated cells exhibited significantly decreased metabolic activity at 24 h and 48 h, and HTP-exposed cells showed a significant decrease after 48 h. Flow cytometry indicated both apoptotic and necrotic cell death following CS exposure, with necrotic cell death being more pronounced. CONCLUSIONS: eCV and HTP demonstrated comparatively reduced detrimental effects on hPDL compared to CS. CLINICAL RELEVANCE: The findings suggest that conventional cigarette smoke poses a substantial risk to periodontal health by significantly impairing cell proliferation and metabolic activity. However, alternatives such as eCV and HTP may offer a comparatively reduced risk.
Subject(s)
Cell Proliferation , Electronic Nicotine Delivery Systems , Periodontal Ligament , Tobacco Products , Periodontal Ligament/cytology , Periodontal Ligament/drug effects , Humans , Cell Proliferation/drug effects , Cells, Cultured , Tobacco Products/toxicity , Flow Cytometry , In Vitro Techniques , Smoke/adverse effects , E-Cigarette Vapor/toxicity , Aerosols , Nicotine/pharmacology , Nicotine/toxicity , Apoptosis/drug effectsABSTRACT
OBJECTIVE: Aortic dissection (AD) is a prevalent and acute clinical catastrophe characterized by abrupt manifestation, swift progression, and elevated fatality rates. Despite smoking being a significant risk factor for AD, the precise pathological process remains elusive. This investigation endeavors to explore the mechanisms by which smoking accelerates AD through ferroptosis induction. METHODOLOGY: In this novel study, we detected considerable endothelial cell death by ferroptosis within the aortic inner lining of both human AD patients with a smoking history and murine AD models induced by ß-aminopropionitrile, angiotensin II, and nicotine. Utilizing bioinformatic approaches, we identified microRNAs regulating the expression of the ferroptosis inhibitor Glutathione peroxidase 4 (GPX4). Nicotine's impact on ferroptosis was further assessed in human umbilical vein endothelial cells (HUVECs) through modulation of miR-1909-5p. Additionally, the therapeutic potential of miR-1909-5p antagomir was evaluated in vivo in nicotine-exposed AD mice. FINDINGS: Our results indicate a predominance of ferroptosis over apoptosis, pyroptosis, and necroptosis in the aortas of AD patients who smoke. Nicotine exposure instigated ferroptosis in HUVECs, where the miR-1909-5p/GPX4 axis was implicated. Modulation of miR-1909-5p in these cells revealed its regulatory role over GPX4 levels and subsequent endothelial ferroptosis. In vivo, miR-1909-5p suppression reduced ferroptosis and mitigated AD progression in the murine model. CONCLUSIONS: Our data underscore the involvement of the miR-1909-5p/GPX4 axis in the pathogenesis of nicotine-induced endothelial ferroptosis in AD.