Dihydromyricetin confers cerebroprotection against subarachnoid hemorrhage via the Nrf2-dependent Prx2 signaling cascade.

BACKGROUND: Several clinical and experimental studies have shown that therapeutic strategies targeting oxidative damage are beneficial for subarachnoid hemorrhage (SAH). A brain-permeable flavonoid, dihydromyricetin (DHM), can modulate redox/oxidative stress and has cerebroprotective effects in several neurological disorders. The effects of DHM on post-SAH early brain injury (EBI) and the underlying mechanism have yet to be clarified. PURPOSE: This work investigated a potential role for DHM in SAH, together with the underlying mechanisms. METHODS: Cerebroprotection by DHM was studied using a SAH rat model and primary cortical neurons. Atorvastatin (Ato) was a positive control drug in this investigation. The effects of DHM on behavior after SAH were evaluated by performing the neurological rotarod and Morris water maze tests, as well as by examining its effects on brain morphology and on the molecular and functional phenotypes of primary cortical neurons using dichlorodihydrofluorescein diacetate (DCFH-DA), immunofluorescent staining, biochemical analysis, and Western blot. RESULTS: DHM was found to significantly reduce the amount of reactive oxygen species (ROS), suppress mitochondrial disruption, and increase intrinsic antioxidant enzymatic activity following SAH. DHM also significantly reduced neuronal apoptosis in SAH rats and improved short- and long-term neurological functions. DHM induced significant increases in peroxiredoxin 2 (Prx2) and nuclear factor erythroid 2-related factor 2 (Nrf2) expression, while decreasing phosphorylation of p38 and apoptotic signal-regulated kinase 1 (ASK1). In contrast, reduction of Prx2 expression using small interfering ribonucleic acid or by inhibiting Nrf2 with ML385 attenuated the neuroprotective effect of DHM against SAH. Moreover, DHM dose-dependently inhibited oxidative damage, decreased neuronal apoptosis, and increased the viability of primary cultured neurons in vitro. These positive effects were associated with Nrf2 activation and stimulation of Prx2 signaling, whereas ML385 attenuated the beneficial effects. CONCLUSION: These results reveal that DHM protects against SAH primarily by modulating the Prx2 signaling cascade through the Nrf2-dependent pathway. Hence, DHM could be a valuable therapeutic candidate for SAH treatment.

Reduced Expression of PRX2/ATPRX1, PRX8, PRX35, and PRX73 Affects Cell Elongation, Vegetative Growth, and Vasculature Structures in Arabidopsis thaliana.

Class III peroxidases (PRXs) are involved in a broad spectrum of physiological and developmental processes throughout the life cycle of plants. However, the specific function of each PRX member in the family remains largely unknown. In this study, we selected four class III peroxidase genes (PRX2/ATPRX1, PRX8, PRX35, and PRX73) from a previous genome-wide transcriptome analysis, and performed phenotypic and morphological analyses, including histochemical staining, in PRX2RNAi, PRX8RNAi, PRX35RNAi, and PRX73RNAi plants. The reduced mRNA levels of corresponding PRX genes in PRX2RNAi, PRX8RNAi, PRX35RNAi, and PRX73RNAi seedlings resulted in elongated hypocotyls and roots, and slightly faster vegetative growth. To investigate internal structural changes in the vasculature, we performed histochemical staining, which revealed alterations in cell wall structures in the main vasculature of hypocotyls, stems, and roots of each PRXRNAi plant compared to wild-type (Col-0) plants. Furthermore, we found that PRX35RNAi plants displayed the decrease in the cell wall in vascular regions, which are involved in downregulation of lignin biosynthesis and biosynthesis-regulated genes' expression. Taken together, these results indicated that the reduced expression levels of PRX2/ATPRX1, PRX8, PRX35, and PRX73 affected hypocotyl and root elongation, vegetative growth, and the vasculature structures in hypocotyl, stem, and root tissues, suggesting that the four class III PRX genes play roles in plant developmental processes.

Prdx1 Interacts with ASK1 upon Exposure to H2O2 and Independently of a Scaffolding Protein.

Hydrogen peroxide (H2O2) is a key redox signaling molecule that selectively oxidizes cysteines on proteins. It can accomplish this even in the presence of highly efficient and abundant H2O2 scavengers, peroxiredoxins (Prdxs), as it is the Prdxs themselves that transfer oxidative equivalents to specific protein thiols on target proteins via their redox-relay functionality. The first evidence of a mammalian cytosolic Prdx-mediated redox-relay-Prdx1 with the kinase ASK1-was presented a decade ago based on the outcome of a co-immunoprecipitation experiment. A second such redox-relay-Prdx2:STAT3-soon followed, for which further studies provided insights into its specificity, organization, and mechanism. The Prdx1:ASK1 redox-relay, however, has never undergone such a characterization. Here, we combine cellular and in vitro protein-protein interaction methods to investigate the Prdx1:ASK1 interaction more thoroughly. We show that, contrary to the Prdx2:STAT3 redox-relay, Prdx1 interacts with ASK1 at elevated H2O2 concentrations, and that this interaction can happen independently of a scaffolding protein. We also provide evidence of a Prdx2:ASK1 interaction, and demonstrate that it requires a facilitator that, however, is not annexin A2. Our results reveal that cytosolic Prdx redox-relays can be organized in different ways and yet again highlight the differentiated roles of Prdx1 and Prdx2.

Astaxanthin ameliorates oxidative stress and neuronal apoptosis via SIRT1/NRF2/Prx2/ASK1/p38 after traumatic brain injury in mice.

BACKGROUND AND PURPOSE: Oxidative stress and neuronal apoptosis play key roles in traumatic brain injury. We investigated the protective effects of astaxanthin against traumatic brain injury and its underlying mechanisms of action. EXPERIMENTAL APPROACH: A weight-drop model of traumatic brain injury in vivo and hydrogen peroxide exposure in vitro model were established. Brain oedema, behaviour tests, western blot, biochemical analysis, lesion volume, histopathological study and cell viability were performed. KEY RESULTS: Astaxanthin significantly reduced oxidative insults on Days 1, 3 and 7 after traumatic brain injury. Neuronal apoptosis was also ameliorated on Day 3. Additionally, astaxanthin improved neurological functions up to 3 weeks after traumatic brain injury. Astaxanthin treatment dramatically enhanced the expression of peroxiredoxin 2 (Prx2), nuclear factor-erythroid 2-related factor 2 (NRF2/Nrf2) and sirtuin 1 (SIRT1), while it down-regulated the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1) and p38. Inhibition of Prx2 by siRNA injection reversed the beneficial effects of astaxanthin against traumatic brain injury. Additionally, Nrf2 knockout prevented the neuroprotective effects of astaxanthin in traumatic brain injury. In contrast, overexpression of Prx2 in Nrf2 knockout mice attenuated the secondary brain injury after traumatic brain injury. Moreover, inhibiting SIRT1 by EX527 dramatically inhibited the neuroprotective effects of astaxanthin and suppressed SIRT1/Nrf2/Prx2/ASK1/p38 pathway both in vivo and in vitro. CONCLUSION AND IMPLICATIONS: Astaxanthin improved the neurological functions and protected the brain from injury after traumatic brain injury, primarily by reducing oxidative stress and neuronal death via SIRT1/Nrf2/Prx2/ASK1/p38 signalling pathway and might be a new candidate to ameliorate traumatic brain injury.

Therapeutic effect of hydrogen peroxide via altered expression of glutathione S-transferase and peroxiredoxin-2 in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) has a high incidence and mortality that epitomizes one of the prominent causes of cancer-related death globally. Novel therapeutic approaches are therefore required. Reactive oxygen species (ROS) are necessary for maintaining cell cycle. Although ROS is involved in HCC progression, hydrogen peroxide (H2O2) has anti-proliferative effect on HCC. METHOD: HCC Huh-7 cells were cultured and incubated with various concentrations of H2O2. Paraoxonase activity, levels of malondialdehyde, glutathione and protein oxidation were measured in treated and untreated Huh-7 cells. Furthermore, untreated and treated Huh-7 cells were subjected to two dimensional gel electrophoresis and identified protein spots which were differentially expressed by LC-MS/MS analysis. qRT-PCR was performed to validate the identified proteins. RESULTS: H2O2 depleted glutathione (GSH) with the concomitant up-regulation of GSTP1 and Prx2. H2O2 also increased malondialdehyde and protein oxidation, decreased the activity of paraoxonase in Huh-7 cells. CONCLUSION: H2O2 could be used as a novel therapeutic agent that might be beneficial in inducing cell cytotoxicity and hence suppress HCC proliferation.

Hydrogen peroxide modulates clock gene expression via PRX2-STAT3-REV-ERBα/ß pathway.

The circadian rhythm is a widespread physiological phenomenon present in almost all forms of life and is constituted by a system of interlocked transcriptional/translational feedback loops (TTFLs). External zeitgebers regulate biological rhythms through the direct or indirect regulation of circadian genes. Oxidative stress is involved in many diseases and injuries, such as ageing, diabetes, Alzheimer's disease, and cancer. Despite an increasing number of studies on circadian rhythm disorders caused by oxidative stress, little is known about the effects of oxidants on clock gene expression and the underlying mechanism. In this study, we found that the protein expression of circadian genes Clock, Bmal1, Per1/2, and Cry1/2 in NIH3T3 cells was upregulated by hydrogen peroxide (H2O2), an important mediator of oxidative stress. In addition, H2O2 modulated the circadian rhythm of Bmal1-luciferase via RORα, REV-ERBα (NR1D1), and REV-ERBß (NR1D2). Further studies showed that H2O2 regulated biological rhythm by PRX2-STAT3-REV-ERBα/ß pathway. These findings provide an accessory loop-related mechanism by which non-transcriptional oscillation interplays with TTFLs.

Identification and molecular characterization of peroxiredoxin 2 in grass carp (Ctenopharyngodon idella).

Peroxiredoxin (Prx), also named thioredoxin peroxidase (TPx), is a selenium independent antioxidant enzyme that can protect organisms from oxidative damage caused by reactive oxygen species (ROS) and is important for immune responses. In this study, the molecular cloning and characterization of a Prx2 homologue (CiPrx2) were described from grass carp (Ctenopharyngodon idella). The full-length cDNA of CiPrx2 was 1163 bp containing 5'-untranslated region (UTR) of 52 bp, a 3'-UTR of 517 bp with the putative polyadenylation consensus signal (AATAAA), an open reading frame (ORF) of 594 bp encoding polypeptides of 197 amino acids with a predicted molecular mass of 21.84 kDa and theoretical isoelectric point of 5.93. The analysis results of multiple sequence alignment and phylogenetic tree confirmed that CiPrx2 belong to the typical 2-Cys Prx subfamily. The CiPrx2 mRNA was ubiquitously expressed in all tested tissues. The temporal expression of CiPrx2 were differentially induced infected with grass carp reovirus (GCRV), polyinosinic:polycytidylic acid (poly I:C) and lipopolysaccharide (LPS) in liver and spleen. Subcellular localization of CiPrx2-GFP fusion proteins were only distributed in the cytoplasm. The purified recombinant CiPrx2 possessed an apparent antioxidant activity and could protect DNA against oxidative damage. Finally, CiPrx2 proteins could obviously inhibit H2O2 and heavy metal toxicity. However, further researches are needed to better understand the regulation of CiPrx2 under oxidative stresses.

Prx2 links ROS homeostasis to stemness of cancer stem cells.

Cancer stem cells (CSC) with low levels of reactive oxygen species (ROS) are resistant to conventional chemotherapy or radiation therapy. Peroxiredoxin 2 (Prx2) is a redox regulatory protein that plays a key role in maintaining ROS homeostasis in the tumor microenvironment. However, despite the role of Prx2 in ROS-mediated signal transduction, the association of Prx2 with stemness via ROS in CSC has not been thoroughly investigated. In this study, we investigated the link between Prx2 and CSC stemness through regulation of ROS levels in hepatocellular carcinoma (HCC) cells. ROS induced CSC stemness reduction and downregulated stem cell markers in Huh7 and SK-HEP1 cells. Prx2 knockdown decreased CSC sphere formation and expression of stem cell makers with increasing intracellular ROS levels. This effect was reversed by the ROS scavengers NAC and GSH in Prx2 knockdown cells. Conversely, we found that Prx2 overexpression promotes CSC stemness and the peroxidase activity of Prx2 is essential for CSC stemness using peroxidase inactive mutant, Prx2C51/172S. More importantly, the hyperoxidation-resistant mutant (Prx2ΔYF), which has a constant ROS scavenging activity even at high concentrations of ROS, increased the CSC stemness and expression of stem cell markers more than Prx2WT under oxidative stress. Taken together, our findings demonstrate that Prx2 links ROS homeostasis to CSC stemness; Prx2 is a mediator between ROS homeostasis and CSC stemness.

Protective and adaptogenic role of peroxiredoxin 2 (Prx2) in neutralization of oxidative stress induced by ionizing radiation.

A radioprotective effect of exogenous recombinant peroxiredoxin 2 (Prx2) was revealed and characterized using an animal model of whole body X-ray irradiation at sublethal and lethal doses. Prx2 belongs to an evolutionarily ancient family of peroxidases that are involved in enzymatic degradation of a wide variety of organic and inorganic hydroperoxides. Apart from that, the oxidized form of Prx2 also exhibits chaperone activity, thereby preventing protein misfolding and aggregation under oxidative stress. Intravenous administration of Prx2 in animals at a concentration of 20 µg/g 15 min before exposure to ionizing radiation contributes to a significantly higher survival rate, suppresses the development of leucopenia and thrombocytopenia, as well as protects the bone marrow cells from genome DNA damage. Moreover, injection of Prx2 leads to suppression of apoptosis, stimulates cell proliferation and results in a more rapid recovery of the cell redox state. Exogenous Prx2 neutralizes the effect of the priming dose on the second irradiation of the cells. The radioprotective properties of exogenous Prx2 are stipulated by its broad substrate peroxidase activity, chaperone activity in the oxidized state, and are also due to the signal-regulatory function of Prx2 mediated by the regulation of the level of hydroperoxides as well as via interaction with redox-sensitive regulatory proteins.

Left ventricular hypertrophy does not prevent heart failure in experimental hypertension.

BACKGROUND: Left ventricular hypertrophy (LVH) secondary to hypertension has been accepted to prevent heart failure (HF) while paradoxically increasing cardiovascular morbi-mortality. OBJECTIVES: To evaluate whether antihypertensive treatment inhibits LVH, restores beta-adrenergic response and affects myocardial oxidative metabolism. METHODS: Ninety spontaneously hypertensive rats (SHR) were distributed into groups and treated (mg/kg, p.o.) with: losartan 30 (L), hydralazine 11 (H), rosuvastatin 10 (R), carvedilol 20 (C). Hypertension control group comprised 18 normotensive rats (Wistar-Kyoto, WKY). Following euthanasia at 16months, contractility was measured in 50% of rats (Langendorff system) before and after isoproterenol (Iso) 10-9M, 10-7M and 10-5M stimulation. Left ventricular weight (LVW) was measured in the remaining hearts, and normalized by BW. Expression of thioredoxin 1 (Trx-1), peroxyredoxin 2 (Prx-2), glutaredoxin 3 (Grx-3), caspase-3 and brain natriuretic peptide (BNP) was determined. RESULTS: Systolic blood pressure (mmHg): 154±3 (L), 137±1 (H), 190±3 (R)*, 206±3 (SHR)*, 183±1 (C)**, and 141±1 (WKY) (*p<0.05 vs. L, H, WKY, **p<0.05 vs. L, H, WKY, SHR). LVW/BW was higher in SHR and R (p<0.05). Groups SHR, R and C evidenced baseline contractile depression. Response to Iso 10-5M was similar in WKY and L. Expression of Trx-1, Prx-2 and Grx-3 increased in C, H, R and L (p<0.01). CONCLUSIONS: Present findings argue against the traditional idea and support that LVH might not be required to prevent HF. Increased expression of thioredoxins by antihypertensive treatment might be involved in protection from HF.

Effects of PRX-2 gene on the phenotype changes of epidermal stem cells differentiating into sweat gland cells / 中华整形外科杂志

Objective@#To investigate the effects of PRX-2 gene on phenotype changes in epidermal stem cells differentiating into sweat gland cells.@*Methods@#Epidermal stem cells and sweat gland cells separated and cultured from healthy foreskin and adult full-thick skin respectively, were identified by immunofluorescence staining. Lentiviral vector-mediated overexpression and knockdown of PRX-2 gene in epidermal stem cells were performed respectively, with empty vector-mediated epidermal stem cells as a control group. Overexpression、blank control and knowdown group′s PRX-2 expressions in gene and protein levels were detected using RT-PCR and Western blot technology. The ESCs of each group were co-cultured with sweat gland cells through transwell plate, and the expressions of CEA and β1 integrin in epidermal stem cells were determined by flow cytometry before and after co-culturing.@*Results@#Epidermal stem cells and sweat gland cells were in line with their respective specific antigens. Before co-cultured, epidermal stem cells highly expressed β1 integrin (98.69±0.67)%, hardly expressed CEA (6.20±3.15)%. After co-cultured, β1 integrin expression levels were showed as knockdown group (19.30±0.53)%<blank control group (65.77±2.32)% <overexpress group (92.63±10.97)%, and CEA expression levels as knockdown (95.43±2.36)%> blank control group (51.20±0.79)%> overexpress group (45.91±0.93)%. There had significant differences between those of each two groups.@*Conclusions@#PRX-2 gene can inhibit the phenotypic change of Epidermal Stem Cells differentiating into Sweat Gland Cells and improve the ability to maintain their own specific antigens.

Uterine Prx2 restrains decidual differentiation through inhibiting lipolysis in mice.

Uterine decidualization, characterized as extensive stromal cell proliferation, differentiation and polyploidization, is a crucial event for successful pregnancy and is tightly regulated by many different molecules and pathways. Prx2, an evolutionarily conserved homeobox transcription factor expressed in both embryos and adults, plays an important role during mesenchymal cell differentiation. However, it remains unclear what the exact function of Prx2 is in the uterine stromal cells, one type of mesenchymal cells. In the present study, employing in vivo and in vitro stromal cell decidualization models, combining adenovirus-mediated overexpression of Prx2, we found that the expression of Prx2 is initiated in the uterine stromal cells once the blastocyst attached to the epithelium and is always detected around the differentiated decidual zone in the anti-mesometrium of the uterus during post-implantation uterine development. Also, overexpression of Prx2 disturbed stromal-decidual differentiation, which is reflected by the decreased expression of decidual/trophoblast prolactin-related protein (Dtprp), the marker for uterine decidualization in mice. Further, we demonstrate that Prx2 overexpression disturbs lipolysis, leading to lipid droplets accumulation in uterine stromal cells, partially mediated by downregulated expression of adipocyte triglyceride lipase. Collectively, these data indicate that uterine Prx2 restrains uterine decidual differentiation through regulating lipid metabolism.

Inhibición de la hipertrofia ventricular izquierda, normalización de la respuesta contráctil cardíaca y estrés oxidativo en hipertensión experimental / Inhibition of Left Ventricular Hypertrophy, Normalization of the Contractile Response and Oxidative Stress in Experimental Hypertension

Introducción y objetivos: La hipertrofia ventricular izquierda secundaria a hipertensión arterial se ha interpretado como un mecanismo de protección para reducir el estrés parietal y prevenir la insuficiencia cardíaca. Sin embargo, paradójicamente, su presencia se acompaña de un incremento de la morbimortalidad cardiovascular. El presente estudio se llevó a cabo con el propósito de evaluar si el tratamiento antihipertensivo crónico inhibe el desarrollo de hipertrofia ventricular izquierda y revierte el deterioro de la respuesta betaadrenérgica cardíaca y su posible relación con cambios en el metabolismo oxidativo del miocardio. Material y métodos: Ratas macho espontáneamente hipertensas (REH, 2 meses de edad) se distribuyeron en grupos (n grupo = 18) grupo según (mg/kg, v.o.): losartán 30 (L), hidralazina 11 (H), rosuvastatina 10 (R), carvedilol 20 (C), agua (control tratamiento). Control hipertensión: 18 ratas normotensas (Wistar-Kyoto, WKY). Periódicamente se registraron la presión arterial sistólica (PAS) (pletismografía, en animales despiertos) y el peso corporal (PC). Luego de 16 meses se practicó eutanasia. El 50% de los corazones se montaron en preparación de Langendorff para medir contractilidad preestímulo y posestímulo betaadrenérgico [isoproterenol (Iso): 10-9M, 10-7M, 10-5M]. En los corazones restantes se registró el peso del ventrículo izquierdo (PVI), que se normalizó por el PC. Se cuantificó la expresión inmunohistoquímica de tiorredoxina 1(Trx-1), peroxirredoxina 2 (Prx-2) y glutarredoxina 3 (Grx-3) (indicadores antioxidantes). Resultados: Peso corporal: similar en todos los grupos. PAS (mm Hg): 154 ± 3 (L), 137 ± 1 (H), 190 ± 3 (R)**, 206 ± 3 (REH)*, 183 ± 1 (C)**, 141 ± 1 (WKY) (*p < 0,05 vs. L, H, WKY; **p < 0,05 vs. L, H, WKY, REH). El PVI/PC de REH y R fue mayor (p < 0,05) respecto de L, H, C y WKY. En C no se observó correlación entre hipertensión e hipertrofia ventricular izquierda. Grupos REH, R y C: mostraron depresión de contractilidad basal vs. L, H y WKY. Respuesta a Iso 10-5 M: similar en WKY y L; disminuida en C, H, R y REH. Expresión de Trx-1, Prx-2 y Grx-3: aumentó en C, H, R y L (1,5-2 veces promedio; p < 0,01 vs. REH y WKY). Conclusiones: El tratamiento con losartán, hidralazina y carvedilol previno el desarrollo de hipertrofia ventricular izquierda. El losartán normalizó la respuesta al isoproterenol en REH. Factores adicionales participarían en el desarrollo de hipertrofia ventricular izquierda con deterioro de la respuesta inotrópica a la estimulación betaadrenérgica en hipertensión. El aumento en la expresión de tiorredoxinas por tratamientos antihipertensivos sugiere un beneficio asociado, aumentando la respuesta antioxidante frente al estrés oxidativo en hipertensión.

Background and objectives: Left ventricular hypertrophy secondary to hypertension has been perceived as a protective mechanism to reduce wall stress and prevent heart failure. However, its presence is paradoxically associated with increased cardiovascular morbidity and mortality The aim of this study was to evaluate whether chronic antihypertensive treatment inhibits the development of left ventricular hypertrophy and normalize the reverting impaired cardiac beta-adrenergic response, and its possible association with changes in myocardial oxidative metabolism. Methods: Spontaneously hypertensive male rats (SHR, 2 months old) were divided into groups (n grupo = 18) according to (mg/ group kg, p.o): losartan 30 (L), hydralazine-11 (H), rosuvastatin 10 (R), carvedilol 20 (C), and water (control treatment). The control hypertension group consisted of 18 normotensive rats (Wistar-Kyoto, WKY). Systolic blood pressure (SBP) (plethysmography in awake animals) and body weight (BW) were measured periodically. The animals were sacrificed at 16 months and 50% of the hearts were mounted in a Langendorff system to measure contractility before and after beta-adrenergic stimulation [isoproterenol (Iso): 10-9 M, 10-7 M, and 10-5 M]. In the remaining hearts left ventricular weight (LVW) was measured and normalized by B W. Immunohistochemical expression of thioredoxin 1 (Trx-1), peroxyredoxin 2 (Prx-2) and glutaredoxin 3 (Grx-3) (antioxidant indicators) was quantified. Results: Body weight was similar in all groups. Systolic blood pressure (mm Hg) was 154 ± 3 (L), 137 ± 1 (H), 190 ± 3 (R)**, 206 ± 3 (SHR)*, 183 ± 1 (C)**, and 141 ± 1 (WKY) (* p < 0.05 vs. L, H, WKY, ** p < 0.05 vs. L, H, WKY, SHR). LVW/BW was higher in SHR and R (p < 0.05) compared with L, H, C and WKY. In C, there was no correlation between hypertension and left ventricular hypertrophy. SHR, R and C evidenced baseline contractile depression vs. L, H and WKY. The response to 10-5 M Iso was similar in WKY and L, and reduced in C, H, R and SHR. The expression of Trx-1, Prx-2 and Grx-3 increased in C, H, R and L (average increase: 1.5-2 times; p < 0.01 vs. SHR and WKY). Conclusions: Treatment with losartan, hydralazine, and carvedilol prevented the development of left ventricular hypertrophy. Losartan normalized the response to isoproterenol in SHR. Additional factors might participate in the development of left ventricular hypertrophy with impaired inotropic response to beta-adrenergic stimulation in hypertension. The increased ex-pression of thioredoxins as a result of antihypertensive treatment suggests an additional benefit, increasing the antioxidant response against oxidative stress in hypertension.

Inhibición de la hipertrofia ventricular izquierda, normalización de la respuesta contráctil cardíaca y estrés oxidativo en hipertensión experimental / Inhibition of Left Ventricular Hypertrophy, Normalization of the Contractile Response and Oxidative Stress in Experimental Hypertension

Introducción y objetivos: La hipertrofia ventricular izquierda secundaria a hipertensión arterial se ha interpretado como un mecanismo de protección para reducir el estrés parietal y prevenir la insuficiencia cardíaca. Sin embargo, paradójicamente, su presencia se acompaña de un incremento de la morbimortalidad cardiovascular. El presente estudio se llevó a cabo con el propósito de evaluar si el tratamiento antihipertensivo crónico inhibe el desarrollo de hipertrofia ventricular izquierda y revierte el deterioro de la respuesta betaadrenérgica cardíaca y su posible relación con cambios en el metabolismo oxidativo del miocardio. Material y métodos: Ratas macho espontáneamente hipertensas (REH, 2 meses de edad) se distribuyeron en grupos (n grupo = 18) grupo según (mg/kg, v.o.): losartán 30 (L), hidralazina 11 (H), rosuvastatina 10 (R), carvedilol 20 (C), agua (control tratamiento). Control hipertensión: 18 ratas normotensas (Wistar-Kyoto, WKY). Periódicamente se registraron la presión arterial sistólica (PAS) (pletismografía, en animales despiertos) y el peso corporal (PC). Luego de 16 meses se practicó eutanasia. El 50% de los corazones se montaron en preparación de Langendorff para medir contractilidad preestímulo y posestímulo betaadrenérgico [isoproterenol (Iso): 10-9M, 10-7M, 10-5M]. En los corazones restantes se registró el peso del ventrículo izquierdo (PVI), que se normalizó por el PC. Se cuantificó la expresión inmunohistoquímica de tiorredoxina 1(Trx-1), peroxirredoxina 2 (Prx-2) y glutarredoxina 3 (Grx-3) (indicadores antioxidantes). Resultados: Peso corporal: similar en todos los grupos. PAS (mm Hg): 154 ± 3 (L), 137 ± 1 (H), 190 ± 3 (R)**, 206 ± 3 (REH)*, 183 ± 1 (C)**, 141 ± 1 (WKY) (*p < 0,05 vs. L, H, WKY; **p < 0,05 vs. L, H, WKY, REH). El PVI/PC de REH y R fue mayor (p < 0,05) respecto de L, H, C y WKY. En C no se observó correlación entre hipertensión e hipertrofia ventricular izquierda. Grupos REH, R y C: mostraron depresión de contractilidad basal vs. L, H y WKY. Respuesta a Iso 10-5 M: similar en WKY y L; disminuida en C, H, R y REH. Expresión de Trx-1, Prx-2 y Grx-3: aumentó en C, H, R y L (1,5-2 veces promedio; p < 0,01 vs. REH y WKY). Conclusiones: El tratamiento con losartán, hidralazina y carvedilol previno el desarrollo de hipertrofia ventricular izquierda. El losartán normalizó la respuesta al isoproterenol en REH. Factores adicionales participarían en el desarrollo de hipertrofia ventricular izquierda con deterioro de la respuesta inotrópica a la estimulación betaadrenérgica en hipertensión. El aumento en la expresión de tiorredoxinas por tratamientos antihipertensivos sugiere un beneficio asociado, aumentando la respuesta antioxidante frente al estrés oxidativo en hipertensión.(AU)

Background and objectives: Left ventricular hypertrophy secondary to hypertension has been perceived as a protective mechanism to reduce wall stress and prevent heart failure. However, its presence is paradoxically associated with increased cardiovascular morbidity and mortality The aim of this study was to evaluate whether chronic antihypertensive treatment inhibits the development of left ventricular hypertrophy and normalize the reverting impaired cardiac beta-adrenergic response, and its possible association with changes in myocardial oxidative metabolism. Methods: Spontaneously hypertensive male rats (SHR, 2 months old) were divided into groups (n grupo = 18) according to (mg/ group kg, p.o): losartan 30 (L), hydralazine-11 (H), rosuvastatin 10 (R), carvedilol 20 (C), and water (control treatment). The control hypertension group consisted of 18 normotensive rats (Wistar-Kyoto, WKY). Systolic blood pressure (SBP) (plethysmography in awake animals) and body weight (BW) were measured periodically. The animals were sacrificed at 16 months and 50% of the hearts were mounted in a Langendorff system to measure contractility before and after beta-adrenergic stimulation [isoproterenol (Iso): 10-9 M, 10-7 M, and 10-5 M]. In the remaining hearts left ventricular weight (LVW) was measured and normalized by B W. Immunohistochemical expression of thioredoxin 1 (Trx-1), peroxyredoxin 2 (Prx-2) and glutaredoxin 3 (Grx-3) (antioxidant indicators) was quantified. Results: Body weight was similar in all groups. Systolic blood pressure (mm Hg) was 154 ± 3 (L), 137 ± 1 (H), 190 ± 3 (R)**, 206 ± 3 (SHR)*, 183 ± 1 (C)**, and 141 ± 1 (WKY) (* p < 0.05 vs. L, H, WKY, ** p < 0.05 vs. L, H, WKY, SHR). LVW/BW was higher in SHR and R (p < 0.05) compared with L, H, C and WKY. In C, there was no correlation between hypertension and left ventricular hypertrophy. SHR, R and C evidenced baseline contractile depression vs. L, H and WKY. The response to 10-5 M Iso was similar in WKY and L, and reduced in C, H, R and SHR. The expression of Trx-1, Prx-2 and Grx-3 increased in C, H, R and L (average increase: 1.5-2 times; p < 0.01 vs. SHR and WKY). Conclusions: Treatment with losartan, hydralazine, and carvedilol prevented the development of left ventricular hypertrophy. Losartan normalized the response to isoproterenol in SHR. Additional factors might participate in the development of left ventricular hypertrophy with impaired inotropic response to beta-adrenergic stimulation in hypertension. The increased ex-pression of thioredoxins as a result of antihypertensive treatment suggests an additional benefit, increasing the antioxidant response against oxidative stress in hypertension.(AU)

Ulinastatin prevents acute lung injury led by liver transplantation.

BACKGROUND: Little is known regarding the effect of ulinastatin (UTI) on acute lung injury (ALI) induced by orthotopic liver transplantation. This study aims to investigate the protective effect of UTI on ALI induced by orthotopic autologous liver transplantation (OALT) in a rat model and to explore the potential underlying mechanism. MATERIALS AND METHODS: Rats were randomly allocated into the following four groups (n = 8 each): (i) sham control group (group sham); (ii) model group (underwent OALT) (group model); (iii) low-dose UTI-treated group (group u1), with UTI (50 U/g) administered intravenously both before the portal vein was occluded and after liver reperfusion started; and (iv) high-dose UTI-treated group (group uh), with UTI (100 U/g) given in the same way as group ul. The lung pathologic parameters, lung water content, and levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, malondialdehyde (MDA), superoxide dismutase (SOD) activity, RanBP-type and C3HC4-type zinc finger-containing protein 1 (RBCK1), and peroxiredoxin-2 (Prx-2) were assessed 8 h after OALT was performed. RESULTS: According to histology, there was severe damage in the lung of group model accompanied by increases in the TNF-α, IL-1ß, IL-6, and MDA levels and decreases in SOD activity and the expression of RBCK1 and Prx-2. UTI treatment significantly reduced the pathologic scores, lung water content, and TNF-α, IL-1ß, IL-6, and MDA levels while restoring the SOD activity and expression of RBCK1 and Prx-2. Furthermore, compared with group u1, treatment with a high dose of UTI resulted in a better protective effect on the lung when assessed by the TNF-α, IL-1ß, IL-6, and MDA levels and SOD activity. CONCLUSIONS: UTI dose-dependently attenuates ALI that is induced by OALT in this rat model, which is mainly due to the suppression of the inflammatory response and oxidant stress, which may, in turn, be mediated by the upregulation of RBCK1 and Prx-2 expression.

Down-regulation of MAPK/NF-κB signaling underlies anti-inflammatory response induced by transduced PEP-1-Prx2 proteins in LPS-induced Raw 264.7 and TPA-induced mouse ear edema model.

Excessive reactive oxygen species (ROS) production plays a crucial role in causing various diseases, including inflammatory disorders. The activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-κB) signaling is implicated in stimulating inflammatory response and cytokines. Peroxiredoxin 2 (Prx2) is a 2-cysteine (Cys) peroxiredoxin capable of removing endogenous hydrogen peroxide (H2O2). PEP-1 peptide, a protein transduction domain, consists of three domains which are used to transduce exogenous therapeutic proteins into cells. The correlation between effectively transduced PEP-1-Prx2 and ROS-mediated inflammatory response is not clear. In the present study, we investigated the protective effects of cell permeable PEP-1-Prx2 on oxidative stress-induced inflammatory activity in Raw 264.7 cells and in a mouse ear edema model after exposure to lipopolysaccharides (LPS) or 12-O-tetradecanoylphorbol-13-acetate (TPA). Transduced PEP-1-Prx2 suppressed intracellular ROS accumulation and inhibited the activity of MAPKs and NF-κB signaling that led to the suppression of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and cytokines in LPS-induced Raw 264.7 cells and TPA-induced mouse ear edema model. Given these results, we propose that PEP-1-Prx2 has therapeutic potential in the prevention of inflammatory disorders.