Mitochondrial reactive oxygen species (ROS) have emerged as an important mechanism of disease and redox signaling in the cardiovascular system. Under basal or pathological conditions, electron ...leakage for ROS production is primarily mediated by the electron transport chain and the proton motive force consisting of a membrane potential (ΔΨ) and a proton gradient (ΔpH). Several factors controlling ROS production in the mitochondria include flavin mononucleotide and flavin mononucleotide–binding domain of complex I, ubisemiquinone and quinone-binding domain of complex I, flavin adenine nucleotide–binding moiety and quinone-binding pocket of complex II, and unstable semiquinone mediated by the Q cycle of complex III. In mitochondrial complex I, specific cysteinyl redox domains modulate ROS production from the flavin mononucleotide moiety and iron–sulfur clusters. In the cardiovascular system, mitochondrial ROS have been linked to mediating the physiological effects of metabolic dilation and preconditioning-like mitochondrial ATP-sensitive potassium channel activation. Furthermore, oxidative post-translational modification by glutathione in complex I and complex II has been shown to affect enzymatic catalysis, protein–protein interactions, and enzyme-mediated ROS production. Conditions associated with oxidative or nitrosative stress, such as myocardial ischemia and reperfusion, increase mitochondrial ROS production via oxidative injury of complexes I and II and superoxide anion radical–induced hydroxyl radical production by aconitase. Further insight into cellular mechanisms by which specific redox post-translational modifications regulate ROS production in the mitochondria will enrich our understanding of redox signal transduction and identify new therapeutic targets for cardiovascular diseases in which oxidative stress perturbs normal redox signaling.
The identity of the specific nitric oxide dioxygenase (NOD) that serves as the main in vivo regulator of O
-dependent NO degradation in smooth muscle remains elusive. Cytoglobin (Cygb) is a recently ...discovered globin expressed in fibroblasts and smooth muscle cells with unknown function. Cygb, coupled with a cellular reducing system, efficiently regulates the rate of NO consumption by metabolizing NO in an O
-dependent manner with decreased NO consumption in physiological hypoxia. Here we show that Cygb is a major regulator of NO degradation and cardiovascular tone. Knockout of Cygb greatly prolongs NO decay, increases vascular relaxation, and lowers blood pressure and systemic vascular resistance. We further demonstrate that downregulation of Cygb prevents angiotensin-mediated hypertension. Thus, Cygb has a critical role in the regulation of vascular tone and disease. We suggest that modulation of the expression and NOD activity of Cygb represents a strategy for the treatment of cardiovascular disease.
Pseudomonas aeruginosa biofilm is commonly associated with chronic wound infection. A FDA approved wireless electroceutical dressing (WED), which in the presence of conductive wound exudate gets ...activated to generate electric field (0.3-0.9V), was investigated for its anti-biofilm properties. Growth of pathogenic P. aeruginosa strain PAO1 in LB media was markedly arrested in the presence of the WED. Scanning electron microscopy demonstrated that WED markedly disrupted biofilm integrity in a setting where silver dressing was ineffective. Biofilm thickness and number of live bacterial cells were decreased in the presence of WED. Quorum sensing genes lasR and rhlR and activity of electric field sensitive enzyme, glycerol-3-phosphate dehydrogenase was also repressed by WED. This work provides first electron paramagnetic resonance spectroscopy evidence demonstrating that WED serves as a spontaneous source of reactive oxygen species. Redox-sensitive multidrug efflux systems mexAB and mexEF were repressed by WED. Taken together, these observations provide first evidence supporting the anti-biofilm properties of WED.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aging is characterized by the development of metabolic dysfunction and frailty. Recent studies show that a reduction in nicotinamide adenine dinucleotide (NAD+) is a key factor for the development of ...age-associated metabolic decline. We recently demonstrated that the NADase CD38 has a central role in age-related NAD+ decline. Here we show that a highly potent and specific thiazoloquin(az)olin(on)e CD38 inhibitor, 78c, reverses age-related NAD+ decline and improves several physiological and metabolic parameters of aging, including glucose tolerance, muscle function, exercise capacity, and cardiac function in mouse models of natural and accelerated aging. The physiological effects of 78c depend on tissue NAD+ levels and were reversed by inhibition of NAD+ synthesis. 78c increased NAD+ levels, resulting in activation of pro-longevity and health span-related factors, including sirtuins, AMPK, and PARPs. Furthermore, in animals treated with 78c we observed inhibition of pathways that negatively affect health span, such as mTOR-S6K and ERK, and attenuation of telomere-associated DNA damage, a marker of cellular aging. Together, our results detail a novel pharmacological strategy for prevention and/or reversal of age-related NAD+ decline and subsequent metabolic dysfunction.
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•Highly potent and specific CD38 inhibitor, 78c, prevents age-related NAD+ decline•Treatment of old mice with 78c improved physiological and metabolic parameters•Inhibition of CD38 promotes an increase in NAD+ and its precursors in tissue•78c is a novel NAD+-boosting therapy to prevent age-related NAD+ decline
A reduction in nicotinamide adenine dinucleotide (NAD+) is associated with aging. Tarragó et al. show physiological and metabolic improvements of aging in old mice given the small molecule 78c, which inhibits the NADase enzyme CD38. Mechanistically, mTORS6K/ERK and telomere-associated DNA damage pathways mitigate the NAD+ decline.
Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. ...Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species.
The NAD(P)
-hydrolyzing enzyme CD38 is activated in the heart during the process of ischemia and reperfusion, triggering NAD(P)(H) depletion. However, the presence and role of CD38 in the major cell ...types of the heart are unknown. Therefore, we characterize the presence and function of CD38 in cardiac myocytes, endothelial cells, and fibroblasts. To comprehensively evaluate CD38 in these cells, we measured gene transcription via mRNA, as well as protein expression and enzymatic activity. Endothelial cells strongly expressed CD38, while only low expression was present in cardiac myocytes with intermediate levels in fibroblasts. In view of this high level expression in endothelial cells and the proposed role of CD38 in the pathogenesis of endothelial dysfunction, endothelial cells were subjected to hypoxia-reoxygenation to characterize the effect of this stress on CD38 expression and activity. An activity-based CD38 imaging method and CD38 activity assays were used to characterize CD38 activity in normoxic and hypoxic-reoxygenated endothelial cells, with marked CD38 activation seen following hypoxia-reoxygenation. To test the impact of hypoxia-reoxygenation-induced CD38 activation on endothelial cells, NAD(P)(H) levels and endothelial nitric oxide synthase (eNOS)-derived NO production were measured. Marked NADP(H) depletion with loss of NO and increase in superoxide production occurred following hypoxia-reoxygenation that was prevented by CD38 inhibition or knockdown. Thus, endothelial cells have high expression of CD38 which is activated by hypoxia-reoxygenation triggering CD38-mediated NADP(H) depletion with loss of eNOS-mediated NO generation and increased eNOS uncoupling. This demonstrates the importance of CD38 in the endothelium and explains the basis by which CD38 triggers post-ischemic endothelial dysfunction.
Repression of mitochondrial respiration represents an evolutionarily ancient cellular adaptation to hypoxia and profoundly influences cell survival and function; however, the underlying molecular ...mechanisms are incompletely understood. Primarily utilizing pulmonary arterial endothelial cells as a representative hypoxic cell type, we identify the iron-sulfur cluster assembly proteins (ISCU1/2) as direct targets for repression by the hypoxia-induced microRNA-210 (miR-210). ISCU1/2 facilitate the assembly of iron-sulfur clusters, prosthetic groups that are critical for electron transport and mitochondrial oxidation-reduction reactions. Under in vivo conditions of upregulating miR-210 and repressing ISCU1/2, the integrity of iron-sulfur clusters is disrupted. In turn, by repressing ISCU1/2 during hypoxia, miR-210 decreases the activity of prototypical iron-sulfur proteins controlling mitochondrial metabolism, including Complex I and aconitase. Consequently, miR-210 represses mitochondrial respiration and associated downstream functions. These results identify important mechanistic connections among microRNA, iron-sulfur cluster biology, hypoxia, and mitochondrial function, with broad implications for cellular metabolism and adaptation to cellular stress.
Ultrasound coupled with activated persulfate can synergistically degrade aqueous organic contaminants. Here, in situ electron paramagnetic resonance spin trapping was used to compare radicals ...produced by ultrasonically activated persulfate (US-PS) and its individual technologies, ultrasound alone (US) and heat-activated persulfate (PS), with respect to temperature. Radicals were trapped using 5,5-dimethyl-1-pyrroline-N-oxide, DMPO, to form detectable nitroxide adducts. Using initial rates of radical adduct formation, and compared to US and PS, US-PS at 40 and 50 °C resulted in the largest synergistic production of radicals. Radicals generated from US were reasonably consistent from 40 to 70 °C, indicating that temperature had little effect on cavitational bubble collapse over this range. However, synergy indexes calculated from initial rates showed that ultrasonic activation of persulfate at the bubble interface changes with temperature. From these results, we speculate that higher temperatures enhance persulfate uptake into cavitation bubbles via nanodroplet injection. DMPO-OH was the predominant adduct detected for all conditions. However, competition modeling and spin trapping in the presence of nitrobenzene and atrazine probes showed that SO4 •– predominated. Therefore, the DMPO-OH signal is derived from SO4 •– trapping with subsequent DMPO-SO4 – hydrolysis to DMPO-OH. Spin trapping is effective in quantifying total radical adduct formation but limited in measuring primary radical speciation in this case.
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