Impact of Dietary Sodium Reduction on the Development of Obesity and Type 2 Diabetes in db/db Mice

The impact of dietary sodium reduction on mouse models of type 2 diabetes is not well understood. Therefore, we analyzed the effect of a low-salt diet on obesity and parameters of type 2 diabetes in db/db mice. Five-week-old male db/db and lean db/m mice were fed a normal salt (0.19% Na⁺, NS) or a low-salt diet (<0.03% Na⁺, LS) for 5 weeks. Body and organ weight and parameters of glucose and insulin tolerance were analyzed. Plasma levels of steroids were determined by liquid chromatography tandem mass spectrometry. Body weight, glucose, and insulin tolerance were not affected by LS. The amount of gonadal adipose tissue showed a trend to be increased by LS whereas liver, pancreas, kidney, heart, and adrenal weight remained unaffected. LS reduced urinary sodium-to-creatinine ratio but did not affect plasma Na⁺ levels in both genotypes. Plasma and urinary potassium-to-creatinine ratio did not differ in all groups of mice. Aldosterone as a major determinant of changes in dietary sodium remained unaffected by LS in db/db mice as well as further investigated steroid hormones. The present study showed reduced sodium-to-creatinine ratio, but no additional effects of dietary sodium reduction on major metabolic parameters and steroid levels in obese and hyper-glycemic db/db mice.

Noncanonical inhibition of caspase-3 by a nuclear microRNA confers endothelial protection by autophagy in atherosclerosis

MicroRNAs (miRNAs) are versatile regulators of gene expression with profound implications for human disease including atherosclerosis, but whether they can exert posttranslational functions to control cell adaptation and whether such noncanonical features harbor pathophysiological relevance is unknown. Here, we show that miR-126-5p sustains endothelial integrity in the context of high shear stress and autophagy. Bound to argonaute-2 (Ago2), miR-126-5p forms a complex with Mex3a, which occurs on the surface of autophagic vesicles and guides its transport into the nucleus. Mutational studies and biophysical measurements demonstrate that Mex3a binds to the central U- and G-rich regions of miR-126-5p with nanomolar affinity via its two K homology domains. In the nucleus, miR-126-5p dissociates from Ago2 and binds to caspase-3 in an aptamer-like fashion with its seed sequence, preventing dimerization of the caspase and inhibiting its activity to limit apoptosis. The antiapoptotic effect of miR-126-5p outside of the RNA-induced silencing complex is important for endothelial integrity under conditions of high shear stress promoting autophagy: ablation of Mex3a or ATG5 in vivo attenuates nuclear import of miR-126-5p, aggravates endothelial apoptosis, and exacerbates atherosclerosis. In human plaques, we found reduced nuclear miR-126-5p and active caspase-3 in areas of disturbed flow. The direct inhibition of caspase-3 by nuclear miR-126-5p reveals a noncanonical mechanism by which miRNAs can modulate protein function.

The transCampus Metabolic Training Programme Explores the Link of SARS-CoV-2 Virus to Metabolic Disease

Currently, we are experiencing a true pandemic of a communicable disease by the virus SARS-CoV-2 holding the whole world firmly in its grasp. Amazingly and unfortunately, this virus uses a metabolic and endocrine pathway via ACE2 to enter our cells causing damage and disease. Our international research training programme funded by the German Research Foundation has a clear mission to train the best students wherever they may come from to learn to tackle the enormous challenges of diabetes and its complications for our society. A modern training programme in diabetes and metabolism does not only involve a thorough understanding of classical physiology, biology and clinical diabetology but has to bring together an interdisciplinary team. With the arrival of the coronavirus pandemic, this prestigious and unique metabolic training programme is facing new challenges but also new opportunities. The consortium of the training programme has recognized early on the need for a guidance and for practical recommendations to cope with the COVID-19 pandemic for the community of patients with metabolic disease, obesity and diabetes. This involves the optimal management from surgical obesity programmes to medications and insulin replacement. We also established a global registry analyzing the dimension and role of metabolic disease including new onset diabetes potentially triggered by the virus. We have involved experts of infectious disease and virology to our faculty with this metabolic training programme to offer the full breadth and scope of expertise needed to meet these scientific challenges. We have all learned that this pandemic does not respect or heed any national borders and that we have to work together as a global community. We believe that this transCampus metabolic training programme provides a prime example how an international team of established experts in the field of metabolism can work together with students from all over the world to address a new pandemic.

The longevity gene mIndy (I'm Not Dead, Yet) affects blood pressure through sympathoadrenal mechanisms

Reduced expression of the plasma membrane citrate transporter INDY (acronym I’m Not Dead, Yet) extends life span in lower organisms. Deletion of the mammalian Indy (mIndy) gene in rodents improves metabolism via mechanisms akin to caloric restriction, known to lower blood pressure (BP) by sympathoadrenal inhibition. We hypothesized that mIndy deletion attenuates sympathoadrenal support of BP. Continuous arterial BP and heart rate (HR) were reduced in mINDY-KO mice. Concomitantly, urinary catecholamine content was lower, and the decreases in BP and HR by mIndy deletion were attenuated after autonomic ganglionic blockade. Catecholamine biosynthesis pathways were reduced in mINDY-KO adrenals using unbiased microarray analysis. Citrate, the main mINDY substrate, increased catecholamine content in pheochromocytoma cells, while pharmacological inhibition of citrate uptake blunted the effect. Our data suggest that deletion of mIndy reduces sympathoadrenal support of BP and HR by attenuating catecholamine biosynthesis. Deletion of mIndy recapitulates beneficial cardiovascular and metabolic responses to caloric restriction, making it an attractive therapeutic target.

Deletion of mIndy reduces blood pressure and heart rate by attenuating catecholamine biosynthesis and recapitulates beneficial cardiovascular and metabolic responses to caloric restriction.

Insulin and obesity transform hypothalamic-pituitary-adrenal axis stemness and function in a hyperactive state

Objective

Metabolic diseases are an increasing problem in society with the brain-metabolic axis as a master regulator of the human body for sustaining homeostasis under metabolic stress. However, metabolic inflammation and disease will trigger sustained activation of the hypothalamic-pituitary-adrenal axis. In this study, we investigated the role of metabolic stress on progenitor cells in the hypothalamic-pituitary-adrenal axis.

Methods

In vitro, we applied insulin and leptin to murine progenitor cells isolated from the pituitary and adrenal cortex and examined the role of these hormones on proliferation and differentiation. In vivo, we investigated two different mouse models of metabolic disease, obesity in leptin-deficient ob/ob mice and obesity achieved via feeding with a high-fat diet.

Results

Insulin was shown to lead to enhanced proliferation and differentiation of both pituitary and adrenocortical progenitors. No alterations in the progenitors were noted in our chronic metabolic stress models. However, hyperactivation of the hypothalamic-pituitary-adrenal axis was observed and the expression of the appetite-regulating genes Npy and Agrp changed in both the hypothalamus and adrenal.

Conclusions

It is well-known that chronic stress and stress hormones such as glucocorticoids can induce metabolic changes including obesity and diabetes. In this article, we show for the first time that this might be based on an early sensitization of stem cells of the hypothalamic-pituitary-adrenal axis. Thus, pituitary and adrenal progenitor cells exposed to high levels of insulin are metabolically primed to a hyper-functional state leading to enhanced hormone production. Likewise, obese animals exhibit a hyperactive hypothalamic-pituitary-adrenal axis leading to adrenal hyperplasia. This might explain how stress in early life can increase the risk for developing metabolic syndrome in adulthood.

•

Insulin enhances proliferation and differentiation of adrenocortical and pituitary progenitors.

•

Obesity leads to hyperactivation and priming of the HPA axis.

•

Obesity leads to overexpression of appetite-regulating genes in the hypothalamus.

•

Obesity leads to a decrease in the expression of appetite-regulating genes in the adrenal gland.

Autophagy unleashes noncanonical microRNA functions

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression which act by guiding AGO (argonaute) proteins to target RNA transcripts in the RNA-induced silencing complex (RISC). This macromolecular complex includes multiple additional components (e.g., TNRC6A) that allow for interaction with enzymes mediating inhibition of translation or RNA decay. However, miRNAs also reside in low-molecular weight complexes without being engaged in target repression, and their function in this context is largely unknown. Our recent findings show that endothelial cells exposed to protective high-shear stress or MTORC inhibition activate the macroautophagy/autophagy machinery to sustain viability by promoting differential trafficking of MIR126 strands and by enabling unconventional features of MIR126-5p. Whereas MIR126-3p is degraded upon autophagy activation, MIR126-5p interacts with the RNA-binding protein MEX3A to form a ternary complex with AGO2. This complex forms on the autophagosomal surface and facilitates its nuclear localization. Once in the nucleus, MIR126-5p dissociates from AGO2 and establishes aptamer-like interactions with the effector CASP3 (caspase 3). The binding to MIR126-5p prevents dimerization and proper active site formation of CASP3, thus inhibiting proteolytic activity and limiting apoptosis. Disrupting this pathway in vivo by genetic deletion of Mex3a or by specific deficiency of endothelial autophagy aggravates endothelial apoptosis and exacerbates the progression of atherosclerosis. The direct inhibition of CASP3 by MIR126-5p reveals a non-canonical mechanism by which miRNAs can modulate protein function and mediate the autophagy-apoptosis crosstalk.

NOX4 is a major regulator of cord blood-derived endothelial colony-forming cells which promotes post-ischaemic revascularization

AIMS

Cord blood-derived endothelial colony-forming cells (CB-ECFCs) are a defined progenitor population with established roles in vascular homeostasis and angiogenesis, which possess low immunogenicity and high potential for allogeneic therapy and are highly sensitive to regulation by reactive oxygen species (ROS). The aim of this study was to define the precise role of the major ROS-producing enzyme, NOX4 NADPH oxidase, in CB-ECFC vasoreparative function.

METHODS AND RESULTS

In vitro CB-ECFC migration (scratch-wound assay) and tubulogenesis (tube length, branch number) was enhanced by phorbol 12-myristate 13-acetate (PMA)-induced superoxide in a NOX-dependent manner. CB-ECFCs highly-expressed NOX4, which was further induced by PMA, whilst NOX4 siRNA and plasmid overexpression reduced and potentiated in vitro function, respectively. Increased ROS generation in NOX4-overexpressing CB-ECFCs (DCF fluorescence, flow cytometry) was specifically reduced by superoxide dismutase, highlighting induction of ROS-specific signalling. Laser Doppler imaging of mouse ischaemic hindlimbs at 7 days indicated that NOX4-knockdown CB-ECFCs inhibited blood flow recovery, which was enhanced by NOX4-overexpressing CB-ECFCs. Tissue analysis at 14 days revealed consistent alterations in vascular density (lectin expression) and eNOS protein despite clearance of injected CB-ECFCs, suggesting NOX4-mediated modulation of host tissue. Indeed, proteome array analysis indicated that NOX4-knockdown CB-ECFCs largely suppressed tissue angiogenesis, whilst NOX4-overexpressing CB-ECFCs up-regulated a number of pro-angiogenic factors specifically-linked with eNOS signalling, in parallel with equivalent modulation of NOX-dependent ROS generation, suggesting that CB-ECFC NOX4 signalling may promote host vascular repair.

CONCLUSION

Taken together, these findings indicate a key role for NOX4 in CB-ECFCs, thereby highlighting its potential as a target for enhancing their reparative function through therapeutic priming to support creation of a pro-reparative microenvironment and effective post-ischaemic revascularization.

Is There a Role for Environmental and Metabolic Factors Predisposing to Severe COVID-19?

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic affects people around the world. However, there have been striking differences in the number of infected individuals and deaths in different countries. Particularly, within Central Europe in countries that are similar in ethnicity, age, and medical standards and have performed similar steps of containment, such differences in mortality rates remain inexplicable. We suggest to consider and explore environmental factors to explain these intriguing variations. Countries like Northern Italy, France, Spain, and UK have suffered from 5 times more deaths from the corona virus infection than neighboring countries like Germany, Switzerland, Austria, and Denmark related to the size of their respective populations. There is a striking correlation between the level of environmental pollutants including pesticides, dioxins, and air pollution such as NO₂ known to affect immune function and healthy metabolism with the rate of mortality in COVID-19 pandemic in these European countries. There is also a correlation with the use of chlorination of drinking water in these regions. In addition to the improvement of environmental protective programs, there are possibilities to lower the blood levels of these pollutants by therapeutic apheresis. Furthermore, therapeutic apheresis might be an effective method to improve metabolic inflammation, altered vascular perfusion, and neurodegeneration observed as long-term complications of COVID-19 disease.

NADPH oxidase 4 mediates the protective effects of physical activity against obesity-induced vascular dysfunction

Aims

Physical activity is one of the most potent strategies to prevent endothelial dysfunction. Recent evidence suggests vaso-protective properties of hydrogen peroxide (H2O2) produced by main endothelial NADPH oxidase isoform 4 (Nox4) in the vasculature. Therefore, we hypothesized that Nox4 connects physical activity with vaso-protective effects.

Methods and results

Analysis of the endothelial function using Mulvany Myograph showed endothelial dysfunction in wild-type (WT) as well as in C57BL/6J/ Nox4−/− (Nox4−/−) mice after 20 weeks on high-fat diet (HFD). Access to running wheels during the HFD prevented endothelial dysfunction in WT but not in Nox4−/− mice. Mechanistically, exercise led to an increased H2O2 release in the aorta of WT mice with increased phosphorylation of eNOS pathway member AKT serine/threonine kinase 1 (AKT1). Both H2O2 release and phosphorylation of AKT1 were diminished in aortas of Nox4−/− mice. Deletion of Nox4 also resulted in lower intracellular calcium release proven by reduced phenylephrine-mediated contraction, whilst potassium-induced contraction was not affected. H2O2 scavenger catalase reduced phenylephrine-induced contraction in WT mice. Supplementing H2O2 increased phenylephrine-induced contraction in Nox4−/− mice. Exercise-induced peroxisome proliferative-activated receptor gamma, coactivator 1 alpha (Ppargc1a), as key regulator of mitochondria biogenesis in WT but not Nox4−/− mice. Furthermore, exercise-induced citrate synthase activity and mitochondria mass were reduced in the absence of Nox4. Thus, Nox4−/− mice became less active and ran less compared with WT mice.

Conclusions

Nox4 derived H2O2 plays a key role in exercise-induced adaptations of eNOS and Ppargc1a pathway and intracellular calcium release. Hence, loss of Nox4 diminished physical activity performance and vascular protective effects of exercise.

VEGF-Trap is a potent modulator of vasoregenerative responses and protects dopaminergic amacrine network integrity in degenerative ischemic neovascular retinopathy

Retinal hypoxia triggers abnormal vessel growth and microvascular hyper-permeability in ischemic retinopathies. Whereas vascular endothelial growth factor A (VEGF-A) inhibitors significantly hinder disease progression, their benefits to retinal neurons remain poorly understood. Similar to humans, oxygen-induced retinopathy (OIR) mice exhibit severe retinal microvascular malformations and profound neuronal dysfunction. OIR mice are thus a phenocopy of human retinopathy of prematurity, and a proxy for investigating advanced stages of proliferative diabetic retinopathy. Hence, the OIR model offers an excellent platform for assessing morpho-functional responses of the ischemic retina to anti-angiogenic therapies. Using this model, we investigated the retinal responses to VEGF-Trap (Aflibercept), an anti-angiogenic agent recognizing ligands of VEGF receptors 1 and 2 that possesses regulatory approval for the treatment of neovascular age-related macular degeneration, macular edema secondary to retinal vein occlusion and diabetic macular edema. Our results indicate that Aflibercept not only reduces the severity of retinal microvascular aberrations but also significantly improves neuroretinal function. Aflibercept administration significantly enhanced light-responsiveness, as revealed by electroretinographic examinations, and led to increased numbers of dopaminergic amacrine cells. Additionally, retinal transcriptional profiling revealed the concerted regulation of both angiogenic and neuronal targets, including transcripts encoding subunits of transmitter receptors relevant to amacrine cell function. Thus, Aflibercept represents a promising therapeutic alternative for the treatment of further progressive ischemic retinal neurovasculopathies beyond the set of disease conditions for which it has regulatory approval. Cover Image for this issue: doi: 10.1111/jnc.14743.

P6285Protective effects of exercise on vascular function are mediated by NADPH oxidase 4

Background/Introduction

Physical activity is one of the most potent strategies to prevent endothelial dysfunction. Recent evidence indicates vaso-protective properties of H2O2 produced by main endothelial NADPH oxidase isoform 4 (Nox4) in the vasculature.

Purpose

Therefore, we hypothesized that Nox4 connects physical activity with vaso-protective effects.

Methods and results

Analysis of endothelial function by Mulvany myograph showed endothelial dysfunction in wild-type as well as in Nox4−/− mice after 20 weeks on high-fat diet. Access to voluntary running wheels during high-fat diet prevented endothelial dysfunction in wild-type but not in Nox4−/− mice. Mechanistically, exercise led to increased H2O2 release in the aorta of wild-type mice with increased phosphorylation of eNOS pathway member AKT serine/threonine kinase 1 (Akt1), subsequently. Both effects were diminished in aortas of Nox4−/− mice. Deletion of Nox4 also led to decreased capacity for intracellular calcium release and reduced phenylephrine-mediated contraction, whereas potassium-induced contraction was unaffected. H2O2 scavenger catalase reduced phenylephrine-contraction in wild-type mice. Supplementation of H2O2 increased phenylephrine-induced contraction in Nox4−/− mice. Exercise induced key regulator of mitochondria biogenesis peroxisome proliferative activated receptor gamma, coactivator 1 alpha (Ppargc1a) in wild-type but not Nox4−/− mice. Furthermore, exercise induced citrate synthase activity and reduced mitochondria mass in the absence of Nox4. Thus, Nox4−/− mice became less active and ran less compared with wild-type mice.

Conclusions

Nox4 derived H2O2 plays a key role in exercise-induced adaptations of eNOS and Ppargc1a pathway and intracellular calcium release. Hence, loss of Nox4 diminished physical activity performance and vascular protective effects of exercise.

Acknowledgement/Funding

This work was supported by a research grant of the German Cardiac Society (DGK) (to H.L.) and DFG (Grant MO 1695/4-1 to H.M.).

Reprint of: Blood Sugar Regulation for Cardiovascular Health Promotion and Disease Prevention: JACC Health Promotion Series

The primary objective of this study was to analyze the most up-to-date evidence regarding whether and how blood sugar regulation influences cardiovascular health promotion and disease prevention by carrying out an umbrella review. Three separate, systematic literature searches identified 2,343 papers in total. Overall, 44 studies were included for data extraction and analysis. The included systematic reviews and meta-analyses published between January 1, 2016, and December 31, 2017, were of good to very good quality (median Overview Quality Assessment Questionnaire score = 17). Identified evidence suggests that cardiovascular disease (CVD) prevention services should consider regulation of blood glucose as a key target for intervention. Furthermore, the recommendations for effective intervention and service development/training described here for prevention of CVD should be adopted into evidence-based practice guidelines. Multidisciplinary teams should be formed to deliver multicomponent interventions in community-based settings. There may be substantial opportunities for integrating CVD and diabetes prevention services.

Blood Sugar Regulation for Cardiovascular Health Promotion and Disease Prevention: JACC Health Promotion Series

The primary objective of this study was to analyze the most up-to-date evidence regarding whether and how blood sugar regulation influences cardiovascular health promotion and disease prevention by carrying out an umbrella review. Three separate, systematic literature searches identified 2,343 papers in total. Overall, 44 studies were included for data extraction and analysis. The included systematic reviews and meta-analyses published between January 1, 2016, and December 31, 2017, were of good to very good quality (median Overview Quality Assessment Questionnaire score = 17). Identified evidence suggests that cardiovascular disease (CVD) prevention services should consider regulation of blood glucose as a key target for intervention. Furthermore, the recommendations for effective intervention and service development/training described here for prevention of CVD should be adopted into evidence-based practice guidelines. Multidisciplinary teams should be formed to deliver multicomponent interventions in community-based settings. There may be substantial opportunities for integrating CVD and diabetes prevention services.

Estrogen determines sex differences in adrenergic vessel tone by regulation of endothelial β-adrenoceptor expression

Vessels of female rats constrict less and relax more to adrenergic stimulation than vessels of males. Although we have reported that these sex-specific differences rely on endothelial β-adrenoceptors, the role of sex hormones in β-adrenoceptor expression and related vessel tone regulation is unknown. We investigated the role of estrogen, progesterone and testosterone on β-adrenoceptor expression and adrenergic vessel tone regulation, along with sex-specific differences in human mammary arteries. The sex-specific differences in vasoconstriction and vasorelaxation in rat vessels were eliminated after ovariectomy in females. Ovariectomy increased vessel vasoconstriction to norepinephrine more than twofold. Vasorelaxations by isoprenaline and a β₃-agonist were reduced after ovariectomy. Estrogen, but not progesterone substitution, restored sex-specific differences in vasoconstriction and vasorelaxation. Vascular mRNA levels of β₁- and β₃- but not β₂-adrenoreceptors were higher in vessels of females compared with males. Ovariectomy reduced these differences by decreasing β₁- and β₃- but not β₂-adrenoreceptor expression in females. Consistently, estrogen substitution restored β₁- and β₃-adrenoreceptor expression. Orchiectomy or testosterone treatment affected neither vasoconstriction and vasorelaxation nor β-adrenoceptor expression in vessels of male rats. In human mammary arteries, sex-specific differences in vasoconstriction and vasorelaxation were reduced after removal of endothelium or treatment with l-NMMA. Vessels of women showed higher levels of β₁- and β₃-adrenoceptors than in men. In conclusion, the sex-specific differences in vasoconstriction and vasorelaxation are common for rat and human vessels. In rats, these differences are estrogen but not testosterone or progesterone dependent. Estrogen determines these differences via regulation of vascular endothelial β₁- and β₃-adrenoreceptor expression. NEW & NOTEWORTHY This study proposes a mechanistic concept regulating sex-specific differences in adrenergic vasoconstriction and vasorelaxation. Estrogen increases vascular β₁- and β₃-adrenoceptor expression in female rats. This and our previous studies demonstrate that these receptors are located primarily on endothelium and when activated by norepinephrine act via nitric oxide (NO). Therefore, β-adrenergic stimulation leads to a more pronounced vasorelaxation in females. Coactivation of endothelial β₁- and β₃-adrenoreceptors leads to higher NO release in vessels of females, ultimately blunting vasoconstriction triggered by activation of smooth muscle α-adrenoceptors.

Abstract 676: Hypoxia Upregulates NADPH Oxidase 4-Mediated Hydrogen Peroxide Release by a HIF-Independent Mechanism in Human Endothelial Cells

NADPH oxidases are important sources of reactive oxygen species in the vascular wall. Recent evidence supports a vasoprotective role of H 2 O 2 produced by the main endothelial isoform Nox4. The impact of hypoxia on NOX4 expression in human endothelial cells and the underlying mechanism remains to be elucidated. In this study, we show that NOX4 mRNA and protein expression was upregulated by hypoxia (1 % O 2 ) in human umbilical vein endothelial cells (HUVEC). Correspondingly, H 2 O 2 production was 2-fold elevated in HUVEC after hypoxia. In contrast to rotenone and oxypurinol, lentiviral downregulation via shNOX4 abolished the elevated hypoxic hydrogen peroxide levels to normoxic values. Hypoxia stabilized the hypoxia-inducible factor (HIF)-1α protein in endothelial cells. Furthermore, VEGF promoter activity and a control promoter containing 3 hypoxia-responsive elements (HRE) were induced by hypoxia. NOX4 promoter deletions up to -119/+239 had an increased basal activity compared to control vector. A full-length and a terminally deleted NOX4 promoter construct missing a putative HRE showed a comparable activity under hypoxic and normoxic conditions, suggesting that NOX4 is not induced on the transcriptional level by hypoxia in endothelial cells. In addition, stabilization of HIF-1α protein under normoxic conditions using DMOG did not change NOX4 mRNA expression in HUVEC. Furthermore, overexpression of HIF-1α did not alter NOX4 promoter activity. Blockade of active transcription by actinomycin D revealed an increased stability of the NOX4 mRNA under hypoxic conditions. In conclusion, this study demonstrates an HIF-independent upregulation of NOX4 as major source of endothelial hydrogen peroxide generation in response to hypoxia. Our data support as a novel mechanism an increased NOX4 mRNA stability under hypoxic conditions in human endothelial cells.

Abstract 241: Impact of Cigarette Smoke, Next Generation Tobacco and Nicotine Products on the Cytotoxic, Oxidative and Pro-Inflammatory Status of THP-1 Cells

Monocytes exhibiting a pro-inflammatory phenotype play a key role in adhesion and development of atherosclerotic plaques. Next generation tobacco and nicotine products (NGPs) are now widely used globally as an alternative to smoking. Little is known about their pro-inflammatory effects on monocytes. We investigated cell viability, anti-oxidant and pro-inflammatory gene and protein expression in THP-1 monocytes exposed to aqueous extracts of conventional cigarettes (CSE), a tobacco heating product (THP) and an electronic cigarette (EC). Pure nicotine was used as additional control. Treatment with CSE reduced cell viability in a dose-dependent manner, whereas all other test agents showed no difference to control. At the highest non-lethal dose of CSE (20%) the following notable mRNA expression changes were observed for CSE, THP and EC respectively, relative to control; HMOX1 (6-fold, <2-fold, <2-fold), NQO1 (3.5-fold, <2-fold, <2-fold), CCL2 (4-fold, 3.5-fold, 2.5-fold), IL1B (4-fold, 3-fold, <2-fold), IL8 (5-fold, 2-fold, 2-fold), TNF (2-fold, 2-fold, <2-fold), CD31 and ICAM1 were below the 2-fold threshold for all products. With respect to protein expression; IL1B (3-fold, <2-fold, <2-fold) and IL8 (3.5-fold, 2-fold, 2-fold) were elevated over the 2-fold threshold, whereas, CD31, ICAM1, TNF and CCL2 were below 2-fold expression for all products. At higher doses, greater inductions were observed with all extracts; however NGP responses were typically lower than CSE. In conclusion, anti-oxidative and pro-inflammatory processes were activated by all products. NGPs showed similar or lower responses relative to controls than CSE exposed cells.