Objective-Heme oxygenase-1 (HO-1), the rate-limiting enzyme of heme degradation, has recently been considered to have protective roles against various pathophysiological conditions. Since we demonstrated that HO-1 overexpression inhibits atherosclerotic formation in animal models, we examined the effect of HO modulation on proinflammatory cytokine production, endothelial NO synthase (eNOS) expression, and endothelium-dependent vascular relaxation responses. Methods and Results-After HO-1 induction by heme arginate (HA), vascular endothelial cell cultures were exposed to oxidized low-density lipoprotein (oxLDL) or tumor necrosis factor-␣ (TNF-␣). HA pretreatment significantly attenuated the production of vascular cell adhesion molecule-1, monocyte chemotactic protein-1, and macrophage colonystimulating factor, suggesting that HO-1 induction attenuates proinflammatory responses. In addition, HO-1 overexpression also alleviated endothelial dysfunction as judged by restoration of attenuated eNOS expression after exposure to oxLDL and TNF-␣. Importantly, impaired endothelium-dependent vascular relaxation responses in thoracic aortic rings from high-fat-fed LDL receptor knockout mice were also improved. These effects were observed by treatment with bilirubin not by carbon monoxide. Key Words: heme oxygenase Ⅲ oxidized LDL Ⅲ endothelial nitric oxide synthase Ⅲ bilirubin Ⅲ carbon monoxide V ascular endothelial cell activation by oxidized LDL (oxLDL) and cytokines such as tumor necrosis factor-␣ (TNF-␣) is considered to play an essential role in the development of atherosclerotic lesions. 1 Activated endothelial cells produce adhesion molecules, chemokines, and growth factors such as vascular cell adhesion molecule-1 (VCAM-1), monocyte chemotactic protein-1 (MCP-1), and macrophage colony-stimulating factor (MCSF). [2][3][4] Numerous studies have shown that these molecules promote multiple steps in the formation of atherosclerotic lesion. 1,3,4 Endothelial dysfunction, which is associated with decreased bioavailability of NO from endothelial NO synthase (eNOS), is also considered to play an important role in atherogenesis. 1,5 NO formed by eNOS has been shown to contribute to vascular smooth muscle cell relaxation and inhibition of platelet aggregation. 1 Heme oxygenase (HO) catalyzes the rate-limiting step of heme degradation in mammals. 6 The products of the reaction are biliverdin, carbon monoxide (CO), and free iron. It has been suggested that biliverdin and CO have cytoprotective effects against various cellular stresses. [7][8][9] We demonstrated that the inducible form of HO (HO-1) is induced in cultured vascular endothelial cells, smooth muscle cells, and macrophages by oxidized low-density lipoprotein (oxLDL), and that high expression of HO-1 results in attenuation of monocyte chemotaxis by oxLDL. 9 In fact, HO-1 is expressed in atherosclerotic lesions. 10,11 We also demonstrated that overexpression of HO-1 inhibits the formation of atherosclerotic lesions by inhibiting lipid peroxidation and by affecting NO meta...

Aim: A growing body of evidence has shown that increased formation of oxidized molecules and reactive oxygen species within the vasculature (i.e., the extracellular space) plays a crucial role in the initiation and progression of atherosclerosis and in the formation of unstable plaques. Peroxiredoxin 4 (PRDX4) is the only known secretory member of the antioxidant PRDX family. However, the relationship between PRDX4 and susceptibility to atherosclerosis has remained unclear. Results: To define the role of PRDX4 in hyperlipidemia-induced atherosclerosis, we generated hPRDX4 transgenic (Tg) and apolipoprotein E (apoE) knockout mice (hPRDX4 +/+ /apoE -/ -). After feeding the mice a high-cholesterol diet, they showed fewer atheromatous plaques, less T-lymphocyte infiltration, lower levels of oxidative stress markers, less necrosis, a larger number of smooth muscle cells, and a larger amount of collagen, resulting in thickened fibrous cap formation and possible stable plaque phenotype as compared with apoE -/ -mice. We also detected greater suppression of apoptosis and decreased Bax expression in hPRDX4 +/+ /apoE -/ -mice than in apoE -/ -mice. Bone marrow transplantation from hPRDX4 +/+ donors to apoE -/ -mice confirmed the antiatherogenic aspects of PRDX4, revealing significantly suppressed atherosclerotic progression. Innovation: In this study, we demonstrated for the first time that PRDX4 suppressed the development of atherosclerosis in apoE -/ -mice fed a high-cholesterol diet. Conclusion: These data indicate that PRDX4 is an antiatherogenic factor and, by suppressing oxidative damage and apoptosis, that it may protect against the formation of vulnerable (unstable) plaques. Antioxid. Redox Signal. 17, 1362-1375.

Aims: Consumption of a high-fructose diet (HFrD) can induce the development of a metabolic syndrome, manifesting as nonalcoholic steatohepatitis (NASH) and/or type 2 diabetes mellitus (T2DM), via a process in which oxidative stress plays a critical role. Peroxiredoxin 4 (PRDX4) is a unique and only known secretory member of the PRDX antioxidant family. However, its putative roles in the development of NASH and/or T2DM have not been investigated. Results: To elucidate the functions of PRDX4 in a metabolic syndrome, we established a nongenetic mouse model of T2DM by feeding mice a HFrD after injecting a relatively low dose of streptozotocin. Compared with wild-type (WT), human PRDX4 transgenic (Tg) mice exhibited significant improvements in insulin resistance, characterized by a lower glucose and insulin concentration and faster responses in glucose tolerance tests. The liver of Tg also showed less severe vesicular steatosis, inflammation, and fibrosis, along with lower lipid concentrations, lower levels of oxidative stress markers, more decreased expression of hepatic aminotransferase, and more reduced stellate cell activation than those in the WT liver, reminiscent of human early NASH. Hepatocyte apoptosis was also significantly repressed in Tg mice. By contrast, serum adiponectin levels and hepatic adiponectin receptor expression were significantly lower in WT mice, consistent with greater insulin resistance in the peripheral liver tissue compared with Tg mice. Innovation and Conclusion: Our data for the first time show that PRDX4 may protect against NASH, T2DM, and the metabolic syndrome by ameliorating oxidative stress-induced injury.

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Abstract-Pulmonary arterial hypertension (PAH) is an intractable disease of the small pulmonary artery that involves multiple inflammatory factors. We hypothesized that a redox-sensitive transcription factor, nuclear factor B (NF-B), which regulates important inflammatory cytokines, plays a pivotal role in PAH. We investigated the activity of NF-B in explanted lungs from patients with PAH and in a rat model of PAH. We also examined a nanotechnology-based therapeutic intervention in the rat model. Immunohistochemistry results indicated that the activity of NF-B increased in small pulmonary arterial lesions and alveolar macrophages in lungs from patients with PAH compared with lungs from control patients. In a rat model of monocrotaline-induced PAH, single intratracheal instillation of polymeric nanoparticles (NPs) resulted in delivery of NPs into lungs for Յ14 days postinstillation. The NP-mediated NF-B decoy delivery into lungs prevented monocrotaline-induced NF-B activation. Blockade of NF-B by NP-mediated delivery of the NF-B decoy attenuated inflammation and proliferation and, thus, attenuated the development of PAH and pulmonary arterial remodeling induced by monocrotaline. Treatment with the NF-B decoy NP 3 weeks after monocrotaline injection improved the survival rate as compared with vehicle administration. In conclusion, these data suggest that NF-B plays a primary role in the pathogenesis of PAH and, thus, represent a new target for therapeutic intervention in PAH. This nanotechnology platform may be developed as a novel molecular approach for treatment of PAH in the future.

. Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest. J Appl Physiol 99: 39 -44, 2005. First published March 10, 2005; doi:10.1152/japplphysiol.01400.2004.-Astronauts experience spine deconditioning during exposure to microgravity due to the lack of axial loads on the spine. Treadmill exercise in a lower body negative pressure (LBNP) chamber provides axial loads on the lumbar spine. We hypothesize that daily supine LBNP exercise helps counteract lumbar spine deconditioning during 28 days of microgravity simulated by bed rest. Twelve sets of healthy, identical twins underwent 6°head-down-tilt bed rest for 28 days. One subject from each set of twins was randomly assigned to the exercise (Ex) group, whereas their sibling served as a nonexercise control (Con). The Ex group exercised in supine posture within a LBNP chamber for 45 min/day, 6 days/wk. All subjects underwent magnetic resonance imaging of their lumbar spine before and at the end of bed rest. Lumbar spinal length increased 3.7 Ϯ 0.5 mm in the Con group over 28-day bed rest, whereas, in the Ex group, lumbar spinal length increased significantly less (2.3 Ϯ 0.4 mm, P ϭ 0.01). All lumbar intervertebral disk heights (L5-S1, L4-5, L3-4, L2-3, and L1-2) in the Con group increased significantly over the 28-day bed rest (P Ͻ 0.05). In the Ex group, there were no significant increases in L 5-S1 and L4-5 disk heights. Lumbar lordosis decreased significantly by 3.3 Ϯ 1.2°d uring bed rest in the Con group (P ϭ 0.02), but it did not decrease significantly in the Ex group. Our results suggest that supine LBNP treadmill exercise partially counteracts lumbar spine lengthening and deconditioning associated with simulated microgravity. simulated microgravity; lumbar spine length; intervertebral disk height; spinal curvature; countermeasures MANY ANATOMICAL AND PHYSIOLOGICAL changes occur when the human body is exposed to microgravity. These changes include cardiovascular deconditioning, loss of exercise capacity, muscle atrophy, and bone loss. Moreover, there are several reports concerning spine deconditioning during adaptation to microgravity, such as spine lengthening (4, 28, 32), intervertebral disk alterations (15), spine curvature increase (29), and back muscle atrophy (17).Because the lumbar spine normally bears ϳ50% body weight (BW) during upright posture on Earth (14, 22, 23), this portion of the spine may be uniquely adapted to gravity. On Earth after overnight bed rest, lumbar length increases ϳ2.7 mm (15). During spaceflight, 4-to 6-cm increase of body height occurs in astronauts (4, 28, 32). Additionally, intervertebral disk volume and cross-sectional area (CSA) increase during simulated and actual microgravity (11,15). Animal experiments document disk biochemistry and degeneration during microgravity (12,25). Thornton and collaborators (29) found a decrease in spinal curvature with exposing to microgravity. Moreover, LeBlanc and coworkers (17) report that even short-duration spacefligh...

1. Nitric oxide (NO) release following repetitive electrical stimulation was studied in the molecular layer of rat cerebellar slices using electrochemical NO probes. 2. In parasagittal slices of the vermis, most Purkinje cells showed climbing fibre responses in response to white matter stimulation without accompanying NO release. 3. In frontal slices, parallel fibre volley potentials and NO release were elicited concurrently by parallel fibre stimulation. 4. The NO release following parallel fibre stimulation was not affected by blockers of non-NMDA, NMDA and metabotropic glutamate receptors. 5. The NO release was reduced significantly (P < 0f001) to 29% of the control level after climbing fibre deafferentation with 3-acetylpyridine treatment.6. The rate of NO release was roughly proportional to the second or third power of the stimulus frequency, and to the third power of the extracellular Ca2+ concentration. 7. The rate of NO release was not affected by nicardipine (10 ASM). It was reduced to 87 + 4%(n = 5, mean + S.E.M.) of the control level by w-conotoxin GVIA (0 3 uM), and to 18 + 4% (n = 4) by w-agatoxin IVA (0 3 uM). 8. Tetanic parallel fibre stimulation potentiated NO release by 24 + 5 % (n = 5). 9. These data indicate that NO is derived mainly from parallel fibres. The relationship between NO release and cerebellar synaptic plasticity is discussed.Of the isoforms of nitric oxide (NO) synthase (NOS), the neuronal type (nNOS) is distributed widely in the brain (Bredt & Snyder, 1994). The activity of nNOS is modulated by calcium through calmodulin, and the product of nNOS, NO, can diffuse through the cell membrane freely. NO may therefore be an intercellular messenger that carries information without depending on synaptic connections. However, the exact function of NO in the brain is not very clear. Among various functions assigned to NO, the role in synaptic plasticity is probably the most enigmatic. NO synthesis in the brain was first detected in the cerebellum (Garthwaite, Charles & Chess-Williams, 1988), where nNOS is present at a high concentration (Bredt, Hwang & Snyder, 1990) and most of the NOS activity is eliminated by disruption of the nNOS gene (Huang, Dawson, Bredt, Snyder & Fishman, 1993). The main synaptic plasticity in the cerebellum is manifested by long-term depression (LTD) in parallel fibre-Purkinje cell synapses, which is suggested to be the cellular mechanism for motor learning (Ito, 1989 (Ito, Sakurai & Tongroach, 1982;Sakurai, 1987). In a study using caged NO, LTD could be induced by light-liberated NO as well as by parallel fibre stimulation (Lev-Ram, Makings, Keitz, Kao & Tsien, 1995), strongly suggesting that NO is released from parallel fibres in order to induce LTD. The purpose of the present study was to demonstrate and characterize possible NO release from parallel fibres.In our previous studies, NO release was demonstrated in the molecular layer of cerebellar slices following white matter stimulation (Shibuki, 1990b;Shibuki & Okada, 1991

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that plays a crucial role in stress-induced apoptosis. Recently, we have reported that suppressed macrophage apoptosis in ASK1 and apolipoprotein E double-knockout mice accelerates atheromatous plaques in the hyperlipidemia-induced atherosclerotic model. However, the pathogenic role of smooth muscle cell (SMC) apoptosis in atherosclerosis still remains unclear. We investigated neointimal remodeling in ligated carotid arteries of ASK1-deficient mice (ASK1(-/-)) for 3 weeks. ASK1(-/-) mice had significantly more suppressed intimal formation, inversely manifesting as potential anti-atherogenic aspects of ASK1 deficiency, characterized by fewer SMCs and less collagen synthesis; and fewer apoptotic SMCs, infiltrating T lymphocytes, and microvessels, associated with decreased apoptosis of luminal endothelial cells, compared with those of wild-type mice. Injured arteries of ASK1(-/-) mice also showed significantly down-regulated expression of pro-apoptotic markers, adhesion molecules, and pro-inflammatory signaling factors. Moreover, tumor necrosis factor-α-induced apoptosis was markedly suppressed in cultured aortic SMCs from ASK1(-/-) mice. These findings suggest that ASK1 accelerates mechanical injury-induced vascular remodeling with activated SMC migration via increased neovascularization and/or enhanced SMC and endothelial cell apoptosis. ASK1 expression, especially in the SMCs, might be crucial, and reciprocally responsible for various pro-atherogenic functions, and SMC apoptosis seems to be detrimental in this model.