Objectives
To evaluate neuronal nitric oxide (NO) synthase (nNOS) phosphorylation, nNOS uncoupling, and oxidative stress in the penis and major pelvic ganglia (MPG), before and after the ...administration of the cAMP‐dependent protein kinase A (PKA) agonist colforsin in a rat model of bilateral cavernous nerve injury (BCNI),which mimics nerve injury after prostatectomy.
Materials and Methods
Adult male Sprague–Dawley rats were divided into BCNI and sham‐operated groups. Each group included two subgroups: vehicle and colforsin (0.1 mg/kg/day i.p.). After 3 days, erectile function (intracavernosal pressure) was measured and penis and MPG were collected for molecular analyses of phospho (P)‐nNOS (Ser‐1412 and Ser‐847), total nNOS, nNOS uncoupling, binding of protein inhibitor of nNOS (PIN) to nNOS, gp91phox subunit of NADPH oxidase, active caspase 3, PKA catalytic subunit α (PKA‐Cα; by Western blot) and oxidative stress (hydrogen peroxide H2O2 and superoxide by Western blot and microdialysis method).
Results
Erectile function was decreased 3 days after BCNI and normalized by colforsin. nNOS phosphorylation on both positive (Ser‐1412) and negative (Ser‐847) regulatory sites, and nNOS uncoupling, were increased after BCNI in the penis and MPG, and normalized by colforsin. H2O2 and total reactive oxygen species production were increased in the penis after BCNI and normalized by colforsin. Protein expression of gp91phox was increased in the MPG after BCNI and was normalized by colforsin treatment. Binding of PIN to nNOS was increased in the penis after BCNI and was normalized by colforsin treatment. Protein expression of active Caspase 3 was increased in the MPG after BCNI and was normalized by colforsin treatment. Protein expression of PKA‐Cα was decreased in the penis after BCNI and normalized by colforsin.
Conclusion
Collectively, BCNI impairs nNOS function in the penis and MPG by mechanisms involving its phosphorylation and uncoupling in association with increased oxidative stress, resulting in erectile dysfunction. PKA activation by colforsin reverses these molecular changes and preserves penile erection in the face of BCNI.
During spaceflight missions, astronauts are exposed to an extreme environment with high levels of radiation and microgravity, which negatively influence the cardiovascular system. With an increased ...development in space exploration and growing interest in manned missions to mars, it is of high importance to evaluate the health risks associated with long‐duration spaceflights. The increased risk of oxidative stress and inflammatory damage post‐spaceflight has been associated with cardiovascular dysfunction, but little is known about the influence of space exposure on erectile function, which is a critical component for quality of life in men. The purpose of this investigation was to determine the influence of long‐duration spaceflight on corpus cavernosum (CC) function. 86 adult male Sprague‐Dawley rats were randomized into 6 different groups with half of them enduring 4‐weeks of hindlimb unloading (HLU), and exposed to sham, 0.75Gy or 1.5Gy of simulated galactic cosmic radiation at the Ground‐based GCR Simulator at the NASA Space Radiation Laboratory (NSRL). Following a 6–9‐month recovery the rats were sacrificed, and CC tissue segments were harvested and mounted into a muscle strip myograph system for ex vivo functional assessment. CC reactivity to six 10‐s,30V‐electric field stimulations with progressive frequencies in the range of 1‐32 Hz targeting the non‐adrenergic non‐cholinergic (NANC) stimulation was assessed. The effects of HLU and radiation were determined by two‐way repeated measures ANOVA. High levels of radiation significantly decreased NANC‐mediated relaxation of the CC. Treatment with nitric oxide synthase (NOS) inhibitor L‐NAME completely inhibited tissue response to electric stimulation, showing that the relaxation was mainly driven by nitric oxide. Incubation of the CC tissue with the xanthine oxidase inhibitor allopurinol, the mitochondria‐targeted antioxidant mito‐TEMPO, and the superoxide dismutase (SOD) mimetic TEMPOL increased the relaxation response of the erectile tissue for the groups exposed to radiation, with little or opposite effect on the groups under no radiation exposure. Upon treatment with the Arginase inhibitor S‐(2‐boronoethyl)‐l‐cysteine (BEC), CC tissue for the groups under radiation exposure showed a significant improvement in relaxation under NANC electric field stimulation. Comparably, western blot analysis showed increased levels of oxidative stress and lipid peroxidation in the corpus cavernosum on the groups under radiation exposure by assessment of 4‐hydroxynonenal (HNE), as well as higher levels of arginase 1 and 2. This information suggests that increased oxidative stress from radiation exposure in long spaceflight trips impairs corpus cavernosum vasoreactivity and exposes new factors to consider with space exploration to ensure that astronauts can return to normal life after long trips in space.
In functional arterial studies using wire myography, the determination of a vessel's standardized normalization factor (factor k) is an essential step to ensure optimal contraction and relaxation by ...the arteries when stimulated with their respective vasoactive agents and to obtain reproducible results. The optimal factor k for several arteries have been determined, however, the optimal initial tension and factor k for the arteries involved in erection remains unknown. Hence, in the present study we set out to determine the optimal factor k for the internal iliac artery, proximal and distal internal pudendal artery (IPA), and dorsal penile artery. After isolating, harvesting, and mounting the arteries from male Sprague-Dawley rats on a multi wire myograph, we tested arterial responsivity to high K+-stimulation when the factor k was set at 0.7, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, and 1.2 to determine the factor k setting that results in the greatest K+-induced active force production for each vessel type. The data showed the optimal factor k is 0.90-0.95 for the dorsal penile, distal internal pudendal and internal iliac arteries while it is 0.85-0.90 for proximal internal pudendal artery. These optimal values corresponded to initial passive tension settings of 1.10±0.16 - 1.46±0.23, 1.28±0.20 - 1.69±0.34, 1.03±0.27 - 1.33±0.31, and 1.33±0.31 - 1.77±0.43 mN/mm for the dorsal penile, distal IP, proximal IP, and internal iliac arteries, respectively.
Nitric oxide (NO) signaling can be mediated not only through classic 3',5'-cyclic guanosine monophosphate but also through S-nitrosylation. However, the impact of S-nitrosylation on erectile function ...and in NO regulation and oxidative stress in the penis remains poorly understood.
To characterize the role of S-nitrosoglutathione reductase (GSNOR), a major regulator of S-nitrosylation homeostasis, on erection physiology and on endothelial NO synthase (eNOS) function and oxidative-nitrosative stress in the penis.
Adult GSNOR-deficient and wild-type (WT) mice were used. Erectile function was assessed in response to electrical stimulation of the cavernous nerve. Total NO in penile homogenates was measured by Griess reaction. Protein S-nitrosylation, eNOS phosphorylation on Ser-1177 (positive regulatory site), eNOS uncoupling, and markers of oxidative stress (4-hydroxy-2-nonenal, malondialdehyde, and nitrotyrosine) in the penis were measured by western blot.
Erectile function, eNOS function, and oxidative stress in the penis of GSNOR-deficient mice.
Erectile function was intact in GSNOR-deficient mice. Total S-nitrosylated proteins were increased (P < .05) in the GSNOR(-/-) compared with WT mouse penis. Although eNOS phosphorylation on Ser-1177 did not differ between the GSNOR(-/-) and WT mouse penises at baseline, electrical stimulation of the cavernous nerve increased (P < .05) phosphorylated eNOS in the WT mouse penis but failed to increase phosphorylated eNOS in the GSNOR(-/-) mouse penis. Total NO production was decreased (P < .05), whereas eNOS uncoupling, 4-hydroxy-2-nonenal, malondialdehyde, and nitrotyrosine were increased (P < .05) in the GSNOR-deficient mouse penis compared with the WT mouse penis.
Transnitrosylation mechanisms play an important role in regulating NO bioactivity in the penis. Deficiency of GSNOR leads to eNOS dysfunction and increased oxidative damage, suggesting that homeostatic eNOS function in the penis is governed by transnitrosylation.
We have previously shown that exercise leads to sustainable cardioprotection through a mechanism involving improved glutathione replenishment. This study was conducted to determine if redox-dependent ...modifications in glutathione reductase (GR) were involved in exercise cardioprotection. Furthermore, we sought to determine if reactive oxygen species generated by NADPH oxidase and/or mitochondria during exercise were triggering events for GR modulations.
Rats were exercised for 10 consecutive days, after which isolated hearts were exposed to ischaemia/reperfusion (25 min/120 min). Exercise protected against infarction and arrhythmia, and preserved coronary flow. The GR inhibitor BCNU abolished the beneficial effects. GR activity was increased following exercise in a redox-dependent manner, with no change in GR protein levels. Because fluorescent labelling of GR protein thiols showed lower amounts of reduced thiols after exercise, we sought to determine the source of intracellular reactive oxygen species that may be activating GR. Subsets of animals were exercised immediately after treatment with either NADPH-oxidase inhibitors apocynin or Vas2870, or with mitoTEMPO or Bendavia, which reduce mitochondrial reactive oxygen species levels. The cardioprotective effects of exercise were abolished if animals exercised in the presence of NADPH oxidase inhibitors, in clear contrast to the mitochondrial reagents. These changes correlated with thiol-dependent modifications of GR.
Adaptive cardioprotective signalling is triggered by reactive oxygen species from NADPH oxidase, and leads to improved glutathione replenishment through redox-dependent modifications in GR.
Animals often retreat to refugia when alarmed and the time they spend hiding reflects an economic decision that trades off reducing predation risk with other beneficial activities. Typically, refugia ...such as burrows are static, but some refugia are dynamic. For species with defensive mutualisms, hiding might be contingent on their mutualist's behaviour. We disturbed and quantified hiding time in magnificent sea anemones, Heteractis magnifica, and their associated domino damselfish, Dascyllus trimaculatus. We found that sea anemone hiding behaviour was dependent on the number and behaviour of their commensal fish: anemones emerged sooner when they had more associated fish and faster returning fish. Together, these results demonstrate that hiding behaviour can be influenced by the behaviour of a commensal; such dynamic mutualisms may be found in other systems.
Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we ...demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection.
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•PD-L1 and IL-10 from suppressive DCs limit CD4 Th1 priming in persistent infection•Loss of CD4 Th1 cells promotes progressive CD8 T cell dysfunction and decay•Reconstitution of Th1 responses enhances antiviral CD8 T cells and viral control
Persistent viral infection suppresses CD4 Th1 responses, but the resulting disease consequences remain unclear. Snell et al. demonstrate that loss of CD4 Th1 cells specifically contributes to CD8 T cell dysfunction and that reconstituting Th1 cells prevents CD8 T cell decay and enhances CD8 T cell activity and viral control.
•Drug-induced lupus is a rare side effect of isoniazid therapy during treatment of Tuberculosis.•Common findings include high titers of anti-nuclear antibody and anti-histone antibody.•Pneumonitis, ...seen as ground-glass opacities on chest tomography, is a potential manifestation of drug-induced lupus.•Histologically this may appear as organizing pneumonitis with septal fibrosis.
Prolonged therapy with isoniazid is used for the treatment of pulmonary tuberculosis. Drug-induced lupus erythematosus is a rare, adverse event associated with isoniazid use and can complicate treatment, especially if it is associated with pneumonitis. The diagnosis is made by clinical suspicion, elevated serum titers of anti-nuclear antibody and anti-histone antibody, and new ground-glass opacities on chest tomography. Bronchoscopy with bronchoalveolar lavage and transbronchial biopsy of affected areas of the lung is useful to increase diagnostic accuracy and differentiate between drug-induced pneumonitis, concomitant infection, or other inflammatory processes. Treatment includes systemic corticosteroids and cessation of isoniazid therapy.
Priapism is a disorder in which prolonged penile erection persists uncontrollably, potentially leading to tissue damage. Priapism commonly afflicts patient populations with severely low nitric oxide ...(NO) bioavailability. Because NO is a primary mediator of erection, the molecular mechanisms involved in priapism pathophysiology associated with low NO bioavailability are not well-understood. The objective of this study was to identify dysregulated molecular targets and signaling pathways in penile tissue of a mouse model of low NO bioavailability that have potential relevance to priapism. Neuronal plus endothelial NO synthase double knockout mice (NOS1/3–/–) were used as a model of low NO bioavailability. Priapic-like activity was demonstrated in the NOS1/3–/– mice relative to wild-type (WT) mice by the measurement of prolonged erections following cessation of electrical stimulation of the cavernous nerve. Penile tissue was processed and analyzed by reverse-phase liquid chromatography tandem mass spectrometry. As a result, 1279 total proteins were identified and quantified by spectral counting, 46 of which were down-regulated and 110 of which were up-regulated in NOS1/3–/– versus WT (P < 0.05). Ingenuity Pathway Analysis of differentially expressed proteins revealed increased protein kinase A and G-protein coupled receptor signaling in NOS1/3–/– penises, which represent potential mechanisms contributing to priapism for secondary to low NO bioavailability.
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