Nicotine Treatment Research Articles

Nicotine Treatment Ameliorates Blood-Brain Barrier Damage After Acute Ischemic Stroke by Regulating Endothelial Scaffolding Protein Pdlim5.

Analysis of a National Institutes of Health (NIH) trial shows that cigarette smoking protected tissue plasminogen activator (tPA)-treated patients from hemorrhage transformation (HT); however, the underlying mechanism is not clear. Damage to the integrity of the blood-brain barrier (BBB) is the pathological basis of HT. Here, we investigated the molecular events of BBB damage after acute ischemic stroke (AIS) using in vitro oxygen-glucose deprivation (OGD) and in vivo mice middle cerebral artery occlusion (MCAO) models. Our results showed that the permeability of bEND.3 monolayer endothelial cells was significantly increased after being exposed to OGD for 2 h. Mice were subjected to 90-min ischemia with 45-min reperfusion, and BBB integrity was significantly damaged, accompanied by tight junction protein occludin degradation, downregulation of microRNA-21 (miR-21), transforming growth factor-β (TGF-β), phosphorylated Smad (p-Smad), plasminogen activator inhibitor-1 (PAI-1), and the upregulation of PDZ and LIM domain protein 5 (Pdlim5), an adaptor protein that has been shown to regulate TGF-β-Smad3 pathway. In addition, pretreatment with two-week nicotine significantly reduced AIS-induced BBB damage and its associated protein dysregulation via downregulating Pdlim5. Notably, AIS did not significantly induce BBB damage in Pdlim5 deficit mice, but overexpression of Pdlim5 in the striatum with adeno-associated virus produced BBB damage and associated protein dysregulation which could be ameliorated by two-week nicotine pretreatment. More important, AIS induced a significant miR-21 decrease, and miR-21 mimics treatment decreased AIS-induced BBB damage by decreasing Pdlim5. Together, these results demonstrate that nicotine treatment alleviates the AIS-compromised integrity of BBB by regulating Pdlim5.

Nicotine Administration Augments Abdominal Aortic Aneurysm Progression in Rats.

Inflammation and elastin degradation are key hallmarks in the pathogenesis of abdominal aortic aneurysms (AAAs). It has been acknowledged that activation of alpha7 nicotinic acetylcholine receptors (α7nAChRs) attenuates inflammation, termed the cholinergic anti-inflammatory pathway (CAP). Thus, we hypothesize that low-dose nicotine impairs the progression of elastase-induced AAAs in rats by exerting anti-inflammatory and anti-oxidative stress properties. Male Sprague-Dawley rats underwent surgical AAA induction with intraluminal elastase infusion. We compared vehicle rats with rats treated with nicotine (1.25 mg/kg/day), and aneurysm progression was monitored by weekly ultrasound images for 28 days. Nicotine treatment significantly promoted AAA progression (p = 0.031). Additionally, gelatin zymography demonstrated that nicotine significantly reduced pro-matrix metalloproteinase (pro-MMP) 2 (p = 0.029) and MMP9 (p = 0.030) activity in aneurysmal tissue. No significant difference was found in the elastin content or the score of elastin degradation between the groups. Neither infiltrating neutrophils nor macrophages, nor aneurysmal messenger RNA (mRNA) levels of pro- or anti-inflammatory cytokines, differed between the vehicle and nicotine groups. Finally, no difference in mRNA levels of markers for anti-oxidative stress or the vascular smooth muscle cells' contractile phenotype was observed. However, proteomics analyses of non-aneurysmal abdominal aortas revealed that nicotine decreased myristoylated alanine-rich C-kinase substrate and proteins, in ontology terms, inflammatory response and reactive oxygen species, and in contradiction to augmented AAAs. In conclusion, nicotine at a dose of 1.25 mg/kg/day augments AAA expansion in this elastase AAA model. These results do not support the use of low-dose nicotine administration for the prevention of AAA progression.

Long-term Stimulation of α7 Nicotinic Acetylcholine Receptor Rescues Hemorrhagic Neuron Loss via Apoptosis of M1 Microglia.

We previously revealed that long-term treatment with nicotine suppresses microglial activation, resulting in a protective effect against thrombin-induced shrinkage of the striatal tissue in organotypic slice cultures. Here, the effect of nicotine on impaired M1 and protective M2 microglial polarization was investigated using the BV-2 microglial cell line in the presence or absence of thrombin. Following nicotine treatment, α7 nicotinic acetylcholine receptor expression transiently increased and then gradually decreased until 14 days. Treatment with nicotine for 14 days slightly polarized M0 microglia to M2b and d subtypes. Co-exposure of thrombin and low concentration of interferon-γ recruited inducible NO synthase (iNOS)- and interleukin-1β-double-positive M1 microglia in a thrombin-concentration-dependent manner. Treatment with nicotine for 14 days significantly decreased the thrombin-induced increase of iNOS mRNA levels and conversely showed a tendency to increase arginase1 mRNA levels. Moreover, treatment with nicotine for 14 days suppressed thrombin-induced phosphorylation of p38 MAPK through the α7 receptor. Repeated intraperitoneal administration of α7 agonist PNU-282987 for 14 days selectively evoked the apoptosis of iNOS-positive M1 microglia at the perihematomal area and showed a neuroprotective effect in an in vivo intracerebral hemorrhage model. These findings revealed that long-term stimulation of α7 receptor causes suppression of thrombin-induced activation of p38 MAPK followed by apoptosis in neuropathic M1 microglia.

A Human Cell-based Assay to Assess the Induction of Vasculature Formation for Non-genotoxic Carcinogenicity Testing Purposes: A Pilot Study.

The induction of vasculature formation is proposed to be a significant mechanism behind the non-genotoxic carcinogenicity of a chemical. The vasculature formation model used in this study is based on the coculture of human primary HUVECs and hASCs. This model was used to develop an assay to assess the induction of vasculature formation. Three assay protocols, based on different conditions, were developed and compared in order to identify the optimal conditions required. Some serum supplements and growth factors were observed to be essential for initiating vasculature formation. Of the studied putative positive reference chemicals, aspartame, sodium nitrite, bisphenol A and nicotine treatment led to a clear induction of vasculature formation, but arsenic and cadmium treatment only led to a slight increase. This human cell-based assay has the potential to be used as one test within a next generation testing battery, to assess the non-genotoxic carcinogenicity of a chemical through the mechanism of vasculature formation induction.

Investigation of adsorption and biosorption features of bio-functionalized poly(GMA-Co-EGDMA) polymer beads in the treatment of nicotine from tobacco industry

The investigation of multifunctional materials for modern enzyme immobilization is an attractive subject in advanced adsorption and biosorption applications. In the present study, the feasibility of immobilization of Lipozyme TL 100L (LPZM) on 3-aminopropyltriethoxysilane (APTES) modified poly-(GMA-co-EGDMA) (PEGDMA) was investigated for adsorption and biosorption of nicotine from aqueous solution. Characterization tests confirmed successful immobilization of lipozyme which significantly altered thermal behavior, surface characteristics, and surface morphology of PEGDMA and PEGDMA/APTES. In addition, the immobilization yields were calculated as 85.0% and 72.0% onto PEGDMA/APTES using physical adsorption and covalent immobilization methods, respectively. The nicotine removal efficiencies were calculated to be 66.4%, 79.0%, 98.9%, and 85.7%, using raw PEGDMA, PEGDMA/APTES, PEGDMA/APTES@LPZM, and PEGDMA/APTES/GU@LPZM, respectively. For the raw PEGDMA, the Langmuir isotherm was best fitted to the adsorption data, while Langmuir-Freundich model described well the adsorption process on PEGDMA/APTES and PEGDMA/APTES@LPZM. The maximum adsorption capacities of Langmuir-Freundlich model increased from 8.118 to 17.32mg/g after enzyme immobilization. The negative enthalpy value, ΔH° (- 10.37kJ/mol), revealed that the nicotine adsorption on PEGDMA/APTES@LPZM was exothermic in nature, which was corroborated by the decrease observed in the number of adsorbed molecules with increasing temperature. In the kinetic experiments, the adsorption on PEGDMA and PEGDMA/APTES@LPZM reached equilibrium with the removal percentages as 66.4% and 98.9% at the end of 3h, respectively. The nicotine adsorption performances in real water matrices were also investigated, and PEGDMA/APTES@LPZM showed satisfactory reusability with removal percentage decreased from 98.9% (1st cycle) to 83.0% (6th cycle).

Acute nicotine exposure blocks aromatase in the limbic brain of healthy women: A [11C]cetrozole PET study

BackgroundOf interest to women's mental health, a wealth of studies suggests sex differences in nicotine addiction and treatment response, but their psychoneuroendocrine underpinnings remain largely unknown. A pathway involving sex steroids could indeed be involved in the behavioural effects of nicotine, as it was found to inhibit aromatase in vitro and in vivo in rodents and non-human primates, respectively. Aromatase regulates the synthesis of oestrogens and, of relevance to addiction, is highly expressed in the limbic brain. MethodsThe present study sought to investigate in vivo aromatase availability in relation to exposure to nicotine in healthy women. Structural magnetic resonance imaging and two [11C]cetrozole positron emission tomography (PET) scans were performed to assess the availability of aromatase before and after administration of nicotine. Gonadal hormones and cotinine levels were measured. Given the region-specific expression of aromatase, a ROI-based approach was employed to assess changes in [11C]cetrozole non-displaceable binding potential. ResultsThe highest availability of aromatase was found in the right and left thalamus. Upon nicotine exposure, [11C]cetrozole binding in the thalamus was acutely decreased bilaterally (Cohen's d = −0.99). In line, cotinine levels were negatively associated with aromatase availability in the thalamus, although as non-significant trend. ConclusionsThese findings indicate acute blocking of aromatase availability by nicotine in the thalamic area. This suggests a new putative mechanism mediating the effects of nicotine on human behaviour, particularly relevant to sex differences in nicotine addiction.

Parkinsonian phenotypes induced by Synphilin-1 expression are differentially contributed by serotonergic and dopaminergic circuits and suppressed by nicotine treatment.

Synphilin-1 is a protein encoded by the human SNCAIP gene whose function has yet to be fully understood. However, it has been linked to familial Parkinson's disease (PD). Synphilin-1 is a major component of the Lewy bodies found in neurons in the substantia nigra pars compacta of PD patients. Synphilin-1 expression in serotonergic and/or dopaminergic neurons of Drosophila melanogaster induces neurodegeneration, as well as motor and non-motor PD like symptoms. In this work, we examined the contribution of the serotonergic and dopaminergic circuits in the development of PD-like phenotypes. We found that olfactory and visual symptoms are majorly contributed by the serotonergic system, and that motor symptoms and reduction in survival are mainly contributed by the dopaminergic system. Chronic nicotine treatment was able to suppress several of these symptoms. These results indicate that both the serotonergic and dopaminergic systems contribute to different aspects of PD symptomatology and that nicotine has beneficial effects on specific symptoms.

Nicotine-Mediated Recruitment of GABAergic Neurons to a Dopaminergic Phenotype Attenuates Motor Deficits in an Alpha-Synuclein Parkinson's Model.

Previous work revealed an inverse correlation between tobacco smoking and Parkinson's disease (PD) that is associated with nicotine-induced neuroprotection of dopaminergic (DA) neurons against nigrostriatal damage in PD primates and rodent models. Nicotine, a neuroactive component of tobacco, can directly alter the activity of midbrain DA neurons and induce non-DA neurons in the substantia nigra (SN) to acquire a DA phenotype. Here, we investigated the recruitment mechanism of nigrostriatal GABAergic neurons to express DA phenotypes, such as transcription factor Nurr1 and DA-synthesizing enzyme tyrosine hydroxylase (TH), and the concomitant effects on motor function. Wild-type and α-syn-overexpressing (PD) mice treated with chronic nicotine were assessed by behavioral pattern monitor (BPM) and immunohistochemistry/in situ hybridization to measure behavior and the translational/transcriptional regulation of neurotransmitter phenotype following selective Nurr1 overexpression or DREADD-mediated chemogenetic activation. We found that nicotine treatment led to a transcriptional TH and translational Nurr1 upregulation within a pool of SN GABAergic neurons in wild-type animals. In PD mice, nicotine increased Nurr1 expression, reduced the number of α-syn-expressing neurons, and simultaneously rescued motor deficits. Hyperactivation of GABA neurons alone was sufficient to elicit de novo translational upregulation of Nurr1. Retrograde labeling revealed that a fraction of these GABAergic neurons projects to the dorsal striatum. Finally, concomitant depolarization and Nurr1 overexpression within GABA neurons were sufficient to mimic nicotine-mediated dopamine plasticity. Revealing the mechanism of nicotine-induced DA plasticity protecting SN neurons against nigrostriatal damage could contribute to developing new strategies for neurotransmitter replacement in PD.

You Don't Know Nicotine: Novel Applications of Nicotinic Therapeutics in Aging

Overall AbstractNicotine binds to nicotinic cholinergic receptors in the brain and the periphery. These receptors are ligand-gated ion channels that modulate other neurotransmitter systems and have important roles in cognitive and emotional functioning. Recent advances have expanded the understanding of how stimulation or blockade of nicotinic receptors affects brain activity, cortical networks, and behavior. While nicotine has been mostly thought of as a substance of abuse connected to tobacco smoking, the potential exists for utilizing nicotine and/or nicotinic stimulation as a therapeutic agent for the treatment of a variety of brain disorders. This symposium will present recent advances in the understanding of how nicotine and nicotinic drugs affect the brain and explore the possible utilization of nicotine for age-related brain disorders. While nicotinic therapeutics has a history dating back to the 1920s, work began in earnest in the 1980s with examining nicotine in Alzheimer's disease. This continued with the development of receptor-selective nicotinic agonists targeted towards Alzheimer’ disease, ADHD, and schizophrenia. These efforts failed, in part because of limited understanding of the appropriate brain system neural targets as well as lack of clarity as to whether the drugs engaged these targets in a meaningful way.Recent research has significantly expanded our understanding of the neural circuitry affected by nicotine and nicotinic stimulation and better human and animal models have offered new insights into the potential for nicotine therapeutics in areas as disparate as hearing loss and stress response mechanisms. Nicotine is now being investigated for its potential in age-related disorders including memory impairment, late life depression, cognitive impairment following cancer treatment and COVID, and age-related hearing loss. The symposium will examine how the effects of nicotine on cognitive functioning differ between older versus younger individuals to explore how nicotinic stimulation benefits may be age specific. We will also present the background and progress of the MIND study, a multi-center nicotine treatment study for mild cognitive impairment, the largest and longest nicotine study of non-smokers ever conducted. New clinical and neural evidence for nicotine as an augmentation treatment for late life depression and the cognitive deficits that accompany this condition will be discussed. Finally, the use of translational animal-human models for discerning the potential beneficial effects of nicotine and the potential for combination therapies to enhance the beneficial effects of nicotine will be presented. These studies of nicotine have broad clinical and scientific significance. If the hypotheses are validated, this will support a novel, broadly available, and inexpensive repurposed intervention for age-related brain disorders and would encourage early treatment to improve symptoms, retard progression of cognitive impairment or improve mood, and lead to combined trials with other agents for brain disorders of aging.

Abstract TP129: Increased Levels Of Matrix Metalloproteinases-induced BBB Dysfunction May Be Responsible For Increased Post-sich Hematoma Growth In Nicotine-exposed Rats.

Spontaneous intracerebral hemorrhage (sICH) is the deadliest type of stroke, accounting for as high as 28% of all strokes. Tobacco use is one of the major risk factors of sICH, and it also worsens outcomes following sICH. In our earlier study, we observed that nicotine exposure increases TNFα levels in brain vessels, impairs BBB integrity, and increases post-sICH hematoma volume in a TNFα-dependent manner compared to saline-exposed controls. Earlier studies have demonstrated interactions between MMPs and TNFα. Increased levels of matrix metalloproteinases (MMPs) have been found in sICH patients and nicotine-exposed individuals. MMPs are involved in BBB breakdown, edema formation, hematoma expansion, and neuronal loss that follow hematoma development after sICH. In the present study, we tested the hypothesis that nicotine exposure-induced increase in TNFα is responsible for increased post-sICH hematoma volume in a MMP-dependent manner. To test our hypothesis, young male and female rats were exposed to chronic nicotine treatment for 2-3 weeks using osmotic pumps containing either saline or nicotine (4.5 mg/kg/day). Levels of MMPs (2, 3, 9, and 12) and GAPDH were evaluated in brain homogenates using Western blot. Nicotine-treated female rats showed a 37% (100±7 vs. 137±10, p<0.05), 144% (100±18 vs. 244±16, p<0.01), 29% (100±7 vs. 129±9, p<0.05), 22% (100±6 vs. 122±6, p<0.05), and 24% (100±6 vs. 124±7, p<0.05) increase in levels of pro and cleaved forms of MMP-3, cleaved form of MMP-9, pro and cleaved forms of MMP-12, respectively, compared to saline-treated female rats. We are in the process of evaluating levels of MMPs in male samples. Considering the role of MMP-9 in BBB integrity, using both TNFα and MMP-9 inhibitors, we are also in the process of evaluating if TNFα increases post-sICH hematoma growth in nicotine-exposed rats via increased levels of MMP-9. The results so far imply that increased TNFα levels in nicotine-exposed rats may be responsible for increased post-sICH hematoma growth in a MMP-dependent manner. Support: James Esther King Biomedical Research Grant 9JK08 and PK is a recipient of the Lois Pope Neuroscience Summer Research Fellowship.

Down-regulation of connexin 43 contributes to structure and function of pulmonary artery in nicotine-administered mice

Dysregulated connexin signaling is implicated in the pathophysiology of pulmonary artery hypertension (PAH). Nicotine affects pulmonary vascular remodeling. However, the potential mechanistic link between connexin signaling and nicotine-induced pulmonary artery remodeling remains unclear. We aimed to investigate the role of connexin 43 (Cx43) in pulmonary artery remodeling in nicotine-administered C57BL/6 J wild-type (WT) and Cx43 heterozygous (Cx43+/−) mice. Hemodynamic parameters and right ventricle pathology were assessed in the mice. Serum biochemical indices of hepatic and renal function were measured. The RT-PCR, immunofluorescence, and western blotting were conducted to evaluate Cx43 mRNA and protein levels. We performed histological staining to identify pulmonary arteries. Wire myography was used to examine contraction and relaxation responses in the pulmonary arteries. Pulmonary vascular permeability was assessed through Evans blue staining. Compared with the WT group, the Cx43+/- group showed lower Cx43 mRNA and protein expression in the pulmonary arteries (P < 0.01). Nicotine treatment significantly increased Cx43 expression (P < 0.01) and induced morphological changes in the pulmonary arteries (P < 0.01). Our findings suggest that Cx43 plays a crucial role in pulmonary artery reactivity and permeability in mice. Furthermore, downregulation of Cx43 expression may contribute to alterations in pulmonary artery structure and function.

Effect of nicotine on cholesterol gallstone formation in C57BL/6J mice fed on a lithogenic diet.

Gallstones are diseases of the biliary system caused by cholesterol supersaturation and/or deficiency in bile salts in bile. Early studies have shown that symptomatic gallstones are primarily a disease of non-smokers, raising the possibility that nicotine can prevent gallstone formation. The present study investigated the effect of nicotine on the formation of cholesterol gallstone in C57BL/6J mice. C57BL/6J mice (eight-weeks-old) were fed a normal or lithogenic diet (basic feed 82.45%, fat 15.8%, cholesterol 1.25% and sodium cholate 0.5%) and divided into five groups: normal diet (ND); ND + high dose nicotine (H); lithogenic diet (LD); LD + low dose nicotine (L) and LD + nicotine (H). They were treated with or without nicotine injection for 10 weeks. Nicotine treatment did not change the rate of cholesterol gallstone formation. There was no difference in TNFα, IL-1β and IL-6 among the five groups. The LD group showed the highest cholesterol levels and there was significant suppression of the total cholesterol, low-density lipoprotein-cholesterol and total bile acid levels in the serum of the nicotine-treated mice. Quantitative PCR showed nicotine altered few bile acid metabolism-related genes expression in liver tissue and significantly altered cholesterol-metabolism genes in gallbladder tissue. Hematoxylin and eosin staining and western blotting showed that protein levels of farnesoid X receptor (FXR) and megalin in the gallbladder increased in the lithogenic-diet mice, which was significantly suppressed in the nicotine-treated mice. In vitro studies using gallbladder epithelial cells showed that chenodeoxycholic acids increased megalin expression, which could be attenuated by nicotine. Nicotine could regulate bile acid metabolism via the FXR-megalin/cubilin pathways, which potentially contribute to cholesterol nucleation and subsequent gallstone formation.

Cardioprotective Effects of Solidago microglossa DC. in Nicotine-Treated Hypertensive Rats.

Solidago microglossa DC. (Asteraceae), "arnica brasileira," is a Brazilian species popularly used to treat hypertension or renal ailments. This study investigated the cardioprotective effects of standardized S. microglossa extract (EESM) in nicotine-treated spontaneously hypertensive rats (SHRs). Moreover, the molecular mechanisms involved in the cardiovascular effects were also investigated. The acute toxicity was evaluated in female Wistar rats. Afterwards, six-month-old male spontaneously hypertensive rats received the EESM (14, 28, and 56 mg/kg), hydrochlorothiazide (25 mg/kg), and vehicle (filtered water; 0.1 mL/100 g) once daily for 28 days. All treatments were associated with 1.8 mg/kg of nicotine. At the end of the experimental period, the renal function, electrocardiographic profile, blood pressure, ventricular function, biochemical parameter, and mesenteric vascular bed reactivity were evaluated. Relative organ weights and cardiac morphometry were also investigated. Nicotine treatment in 6-month-old SHRs induced a significant reduction in renal function, with reduced urinary volume and lower renal elimination of sodium and creatinine. In addition, serum markers of the redox state and blood pressure levels remained significantly elevated, contributing to changes in vascular reactivity and left ventricular hypertrophy associated with reduced ventricular function. After 28 days of treatment, we found that the highest dose of EESM could mitigate all renal and cardiovascular changes developed by the nicotine-treated hypertensive rats. This study presented EESM as a possible cardioprotective drug that prevents cardiovascular dysfunctions in nicotine-treated hypertensive rats. Our data suggest EESM as a potential adjuvant therapy when cardioprotective effects are required.

Ameloriate Effect of Glucose Monohydrate on Nicotine Sulfate-induced Toxicity and Teratogenicity in Xenopus embryos: an Experimental Study

It is well documented that nicotine causes low birth weight, preterm birth, pregnancy difficulties, lower fertility, inhibition of spermatogenesis, and decreased steroidogenesis and potassium channels conductance of Xenopus oocytes. Lung cancer is the most well-known adverse impact of nicotine. This work used a 96-hour FETAX test to examine how concurrent administration of glucose monohydrate modifies the effects of exposure to nicotine, nicotine sulfate, and/or glucose on ion channels and membrane potential in Xenopus leavis embryos at an early stage of development. In-vitro fertilised embryos were treated with nicotine and glucose alone or in combination for this aim, and the effects of those treatments were then assessed for potential teratogenic effects. At the conclusion of the FETAX technique, the ratios of healthy, abnormal, and dead embryos were calculated, and the length of embryos in each treatment group was assessed. The ratios of abnormal and dead embryos were considerably higher with nicotine treatment alone compared to controls. Compared to the results of the nicotine-alone treatment group, the ratio of aberrant embryos was marginally reduced by concurrent glucose and nicotine therapy. In contrast, the ratio of normal embryos was raised. Additionally, treatments with glucose, nicotine, and Nic+Glu significantly altered the resting membrane potentials of fertilised oocytes (p &lt; 0.001). Our findings indicated that the simultaneous treatment groups that also received glucose had a protective impact on embryos. Such structured, more sophisticated research is required to confirm these findings.

The effect of nicotine and lead on neuron morphology, function, and ɑ-Synuclein levels in a C. elegans model

An electronic cigarette (e-cigarette) is a device that simulates cigarette-tobacco smoking by atomizing a liquid into an inhalable vapor. It is often billed as a smoking cessation device that is safer than cigarette smoking, however, these devices are feared to work as a gateway to cigarette smoking through nicotine addiction. In addition to e-cigarette injury and death, there are also neurological implications to using an e-cigarette. Our research aimed to determine the effect of chemicals commonly found in e-cigarette aerosol, specifically nicotine and lead, on dopaminergic neuron morphology and ɑ-synuclein levels using the model organism Caenorhabditis elegans. Our hypothesis stated that should exposure to these chemicals have an effect, then we would observe negative neurological implications such as changes in dopamine neuron morphology and possible neurodegeneration. We used transgenic C. elegans to assess the effects of nicotine and lead on ɑ-synuclein levels and neuron morphology. C. elegans were treated with different doses of lead, nicotine, or a mixture of to simulate the neurological effects of e-cigarette use. We determined dopamine and acetylcholine-dependent behavior using a 1-nonanol assay and an aldicarb assay, respectively. We observed a significant dopaminergic deterioration upon the treatment of lead and nicotine. At higher concentration of each treatment (lead, nicotine, and the combination), we observed C. elegans(NL5901 and BZ555) strains were smaller with an increase in protein aggregation. Our findings indicate that using e-cigarettes may induce morphological changes that are not favorable for normal brain function and could lead to a decrease in individuals’ e-cigarette use.

EFFECTS OF BISPHENOL A AND NICOTINE ON CYTOCHROME P450S IN BRAIN AND LIVER OF PREGNANT RATS

Bisphenol A (BPA), a widely used chemical, is associated with endocrine disruption through its interactions with the aryl hydrocarbon receptor (AhR). BPA crosses into the human body mostly through migration from plastic packaging into the daily diet. AhR regulates the expression of drug-metabolizing enzymes (DMEs), including numerous CYP450s, and mediates xenobiotic reactions. This study aims at examining how the expression of CYP450s expression is affected, in the brain and liver of pregnant rats, by exposure to BPA and nicotine. Pregnant female Sprague-Dawley dams were exposed to increasing doses of BPA; 0 (control), 50, 500, and 5000 g/kg/day , or in combination with nicotine; 3000 µg/kg/day, through drinking water. Brain and liver tissues were isolated after 2 weeks of exposure, and western blotting was used to assess the expression of selected protein targets. The results showed that BPA exposure decreased the expression levels of CYP1A1 and CYP1B1 in the brain (by 55% and 79% respectively). It also decreased CYP2E1 levels in the brain (by 42%), but increased its levels in the liver (by 126%). Moreover, BPA exposure decreased levels of CYP19A1 and ARNT in the liver (by 51% and 44% respectively), and decreased those of AhRR (AhR repressor) in the brain (by 28%). On the other hand, nicotine treatment exhibited an inhibitory effect with CYP1A1, CYP1B1, and AhRR in the brain (by 67%, 78%, and 13% respectively), whereas, it inhibited CYP1A1, CYP19A1, and ARNT (AhR Nuclear Translocator) in the liver (47%, 54%, and 63% respectively). In conclusion, adult brain and liver tissues showed BPA sensitivity, which disrupts CYP450s expression, and is modulated by nicotine. The observed effects could be mediated by AhR-ARNT-dependent or independent pathways, which need to be investigated further.

Nicotine ameliorates inflammatory mediators in RU486 induced preterm labor model through activating cholinergic anti-inflammatory pathway.

Preterm birth is a global public health threat. Inflammatory reaction is thought to mediate preterm birth. The role of nicotine, an anti-inflammatory agent that is mediated by cholinergic anti-inflammatory pathways (CAP), remains unclear in the pathogenesis. Pregnant rats were randomly divided into four groups (20 rats each): pregnant control group (P), RU486-treated group (PTL), RU486 and nicotine-treated group (PTL+N), RU486, nicotine and α-BGT treated group (PTL+N+A). Rats were administered RU486 (1.0mg/kg) by subcutaneous injection on gestational day (GD) 18 to establish PTL model. Subcutaneous injection of nicotine (1mg/kg) was administered daily from GD 16 to 18. α-BGT (1µg/kg) was administrated subcutaneously in two sessions and each session was 30min prior to nicotine. TNF-α, IL-1β, IL-4, IL-6, IL-10 in myometrium and serum were detected by Luminex. Macrophage infiltration and α7nAChR were detected by IHC. We established a RU486-induced preterm labor rat model. Preterm labor was associated with a striking upregulation inflammatory mediators and increased macrophage infiltration. Nicotine significantly prolonged gestation (P&lt;0.05) and α-BGT treatment reversed the prolonged interval (P&lt;0.05). The cytokines all markedly elevated at 12h, but deceased after delivery (P&lt;0.05). The IL-1β and TNF-α in serum were significantly increased in PTL group vs P group (P&lt;0.05), and decreased after nicotine treatment (P&lt;0.05). The cytokines IL-1β, IL-4, IL-6, IL-10 and TNF-α in myometrium increased as the same trend as in serum. Nicotine treatment also downregulated the expression of α7nAChR in pregnant tissue. We confirmed the increased inflammation in preterm birth. Nicotine was able to down-regulate the inflammatory mediates and prolong the pregnant duration in PTL model, which might be induced by activating α7nAChR through CAP. This study provides a novel evidence supporting the future development of therapeutic target for preterm birth.

Impaired autophagy flux by lncRNA NEAT1 is critical for inflammation factors production in human periodontal ligament stem cells with nicotine treatment.

Periodontitis is the top reason for tooth loss, and smoking significantly increases severe periodontitis risk. Defective autophagy has been reported to play a vital role in periodontitis. This study aimed to elucidate the relationship between autophagy and inflammation factors production in nicotine-treated periodontal ligament stem cells (PDLSCs) and the underlying mechanism. In this study, transmission electron microscopy, immunofluorescence, and the mCherry-GFP-LC3 plasmid were used to study autophagy flux. The gene levels of inflammation factors and long noncoding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) were detected by quantitative real-time PCR (qRT-PCR). Western blot was performed to assess the protein levels of autophagic markers and α7 nicotinic acetylcholine receptor (α7nAChR). We found that nicotine impaired autophagosome-lysosome fusion and lysosome functions to block autophagy flux, contributing to inflammatory factors production in nicotine-treated PDLSCs. Moreover, nicotine upregulated NEAT1 by activating α7nAChR. NEAT1 decreased autophagy flux by downregulating syntaxin 17 (STX17). Our data indicate that NEAT1-decreased autophagy flux is pivotal for inflammation factors production in nicotine-treated PDLSCs.

Regulation of Cisplatin Resistance in Lung Cancer Cells by Nicotine, BDNF, and a β-Adrenergic Receptor Blocker.

It is well-recognized that cigarette smoking is a primary risk factor in the development of non-small cell lung cancer (NSCLC), known to account for ~80% of all lung cancers with nicotine recognized as the major addictive component. In investigating the effect of nicotine, brain-derived neurotrophic factor (BDNF), and the β-adrenergic receptor blocker, propranolol, on sensitivity of NSCLC cell lines, A549 and H1299, to cisplatin, we found increased cell viability, and enhanced cisplatin resistance with nicotine and/or BDNF treatment while opposite effects were found upon treatment with propranolol. Cell treatment with epinephrine or nicotine led to EGFR and IGF-1R activation, effects opposite to those found with propranolol. Blocking EGFR and IGF-1R activation increased cell sensitivity to cisplatin in both cell lines. PI3K and AKT activities were upregulated by nicotine or BDNF and downregulated by cell treatment with inhibitors against EGFR and IGF-1R and by propranolol. Apoptosis and cell sensitivity to cisplatin increased upon co-treatment of cells with cisplatin and inhibitors against PI3K or AKT. Our findings shed light on an interplay between nicotine, BDNF, and β-Adrenergic receptor signaling in regulating survival of lung cancer cells and chemoresistance which can likely expand therapeutic opportunities that target this regulatory network in the future.

Genetic differences in nicotine sensitivity and metabolism in C57BL/6J and NOD/ShiLtJ mouse strains

Genetic background impacts sensitivity to nicotine's rewarding and aversive effects and metabolism, which influences susceptibility to nicotine addiction. This is important because sensitivity to nicotine influences susceptibility to nicotine addiction. Thus, understanding genetic contribution to nicotine sensitivity can aid in identifying risk factors for nicotine addiction. Genetic variability in addiction phenotypes can be modeled in rodent systems, and comparisons of nicotine sensitivity in inbred mice can identify contributing genetic substrates. Our laboratory has identified differences in nicotine sensitivity in male mice from two inbred mouse strains, C57BL/6J and NOD/ShiLtJ. We found that the NOD/ShiLtJ strain experienced greater nicotine-induced locomotor depression and hypothermia than the C57BL/6J strain. To investigate possible differences in nicotine metabolism between strains, subjects were treated with acute nicotine and serum and urine samples were analyzed using LC-MS/MS to quantify nicotine and metabolites. This analysis revealed that NOD/ShiLtJ mice had similar serum nicotine but lower cotinine and 3′-hydroxycotinine levels after nicotine treatment when compared to C57BL/6J mice. Possible genetic factors mediating strain differences were identified by surveying nicotine sensitivity- and metabolism-related genes within the Mouse Phenome Database SNP retrieval tool. Polymorphisms were found in 15 of the 26 examined gene sequences. Liver expression levels of nicotine metabolism-related genes (Cyp2a5, Cyp2a4, and Aox1) were measured using qPCR. NOD/ShiLtJ mice showed lower expression of Cyp2a5 and Cyp2a4 and greater expression of Aox1 in liver tissue. These data demonstrate complex differences in nicotine sensitivity and metabolism driven by genetic differences between C57BL/6J and NOD/ShiLtJ inbred mouse strains.