Center for Surgical Research and Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
Submitted 11 December 2007
; accepted in final form 3 April 2008
Studies have shown ...that p38 MAPK and nitric oxide (NO), generated by endothelial NO synthase (eNOS), play key roles under physiological and pathophysiological conditions. Although administration of 17β-estradiol (E 2 ) protects cardiovascular injury from trauma-hemorrhage, the mechanism by which E 2 produces those effects remains unknown. Our objective was to determine whether the E 2 -mediated activation of myocardial p38 MAPK and subsequent eNOS expression/phosphorylation would protect the heart following trauma-hemorrhage. To study this, male Sprague-Dawley rats underwent soft-tissue trauma (midline laparatomy) and hemorrhagic shock (mean blood pressure 35–40 mmHg for 90 min), followed by fluid resuscitation. Animals were pretreated with specific p38 MAPK inhibitor SB-203580 (SB; 2 mg/kg), and nonselective NO synthase inhibitor N G -nitro- L -arginine methyl ester ( L -NAME; 30 mg/kg) 30 min before vehicle (cyclodextrin) or E 2 (100 µg/kg) treatment, followed by resuscitation, and were killed 2 h thereafter. Cardiovascular performance and other parameters were measured. E 2 administration following trauma-hemorrhage increased cardiac p38 MAPK activity, eNOS expression and phosphorylation at Ser 1177 , and nitrate/nitrite levels in plasma and heart tissues; these were associated with normalized cardiac performance, which was reversed by SB administration. In addition, E 2 also prevented trauma-hemorrhage-induced increase in cytokines (IL-6 and TNF- ), chemokines (macrophage inflammatory protein-2 and cytokine-induced neutrophil chemoattractant-1), and ICAM-1, which was reversed by L -NAME administration. Administration of E 2 following trauma-hemorrhage attenuated cardiac tissue injury markers, myeloperoxidase activity, and nitrotyrosine level, which were reversed by treatment with SB and L -NAME. The salutary effects of E 2 on cardiac functions and tissue protection following trauma-hemorrhage are mediated, in part, through activation of p38 MAPK and subsequent eNOS expression and phosphorylation.
nitric oxide synthase; cytokine; chemokine; myeloperoxidase
Address for reprint requests and other correspondence: I. H. Chaudry, Center for Surgical Research, Univ. of Alabama at Birmingham, 1670 Univ. Blvd., G094Volker Hall, Birmingham, AL 35294-0019 (e-mail: Irshad.Chaudry{at}ccc.uab.edu )
Studies have shown that p38 MAPK and nitric oxide (NO), generated by endothelial NO synthase (eNOS), play key roles under physiological and pathophysiological conditions. Although administration of ...17beta-estradiol (E2) protects cardiovascular injury from trauma-hemorrhage, the mechanism by which E2 produces those effects remains unknown. Our objective was to determine whether the E2-mediated activation of myocardial p38 MAPK and subsequent eNOS expression/phosphorylation would protect the heart following trauma-hemorrhage. To study this, male Sprague-Dawley rats underwent soft-tissue trauma (midline laparatomy) and hemorrhagic shock (mean blood pressure 35-40 mmHg for 90 min), followed by fluid resuscitation. Animals were pretreated with specific p38 MAPK inhibitor SB-203580 (SB; 2 mg/kg), and nonselective NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 30 mg/kg) 30 min before vehicle (cyclodextrin) or E2 (100 microg/kg) treatment, followed by resuscitation, and were killed 2 h thereafter. Cardiovascular performance and other parameters were measured. E2 administration following trauma-hemorrhage increased cardiac p38 MAPK activity, eNOS expression and phosphorylation at Ser(1177), and nitrate/nitrite levels in plasma and heart tissues; these were associated with normalized cardiac performance, which was reversed by SB administration. In addition, E2 also prevented trauma-hemorrhage-induced increase in cytokines (IL-6 and TNF-alpha), chemokines (macrophage inflammatory protein-2 and cytokine-induced neutrophil chemoattractant-1), and ICAM-1, which was reversed by l-NAME administration. Administration of E2 following trauma-hemorrhage attenuated cardiac tissue injury markers, myeloperoxidase activity, and nitrotyrosine level, which were reversed by treatment with SB and l-NAME. The salutary effects of E2 on cardiac functions and tissue protection following trauma-hemorrhage are mediated, in part, through activation of p38 MAPK and subsequent eNOS expression and phosphorylation.
Reduced immune function is frequently a consequence of serious injury such as trauma-hemorrhage (T-H). Injury may lead to reduced T-cell activation, resulting in decreased engagement of costimulatory ...molecules after antigen recognition and in subsequent immunological compromise and anergy. We hypothesized that inhibition of CD28 expression is one possible mechanism by which immune functions are suppressed after T-H. Male C3H/HeN mice (with or without ovalbumin immunization) were subjected to sham operation or T-H and sacrificed after 24 hours. Splenic T cells were then stimulated with concanavalin A or ovalbumin in vivo or in vitro , and CD28, cytotoxic T-lymphocyte antigen 4 (CTLA-4), CD69, and phospho-Akt expression was determined. T-cell proliferation/cytokine production was measured in vitro . Stimulation-induced CD69, CD28, and phospho-Akt up-regulation were significantly impaired after T-H compared with sham-operated animals; however, CTLA-4 expression was significantly higher in the T-H group. Over a 3-day span, stimulated T cells from sham-operated animals showed significantly higher proliferation compared with the T-H group. IL-2 and IFN-γ were elevated in sham-operated animals, whereas IL-4 and IL-5 rose in the T-H group, revealing a shift from TH 1 to TH 2 type cytokine production after T-H. Dysregulation of the T-cell costimulatory pathway is therefore likely to be a significant contributor to post-traumatic immune suppression.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although studies have shown that 17beta-estradiol (estradiol) normalized Kupffer cell function following trauma-hemorrhage, the mechanism by which E2 maintains immune function remains unclear. ...Activation of Toll-like receptor 4 (TLR4) initiates an inflammatory cascade, involving activation of p38 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and nuclear factor-kappaB (NF-kappaB). This leads to the release of proinflammatory cytokines. Thus, we hypothesized that the salutary effects of estradiol on Kupffer cell function following trauma-hemorrhage are mediated via negative regulation of TLR4-dependent p38 MAPK and NF-kappaB. TLR4 mutant (C3H/HeJ) and wild type (C3H/HeOuJ) mice were subjected to trauma-hemorrhage (mean BP 35+/-5 mmHg approximately 90 min, then resuscitation) or sham operation. Administration of estradiol following trauma-hemorrhage in wild type mice decreased Kupffer cell TLR4 expression as well as prevented the phosphorylation of p38 MAPK and NF-kappaB. This was accompanied by normalization of Kupffer cell production capacities of IL-6, TNF-alpha, macrophage inflammatory protein (MIP)-1alpha, and MIP-2 and the decrease in plasma cytokine levels. In contrast, TLR4 mutant mice did not exhibit the increase in Kupffer cell p38 MAPK and NF-kappaB activation, cytokine production, or the increase in circulating cytokine levels following trauma-hemorrhage. No difference was observed in activation of PI3K among groups. These results suggest that the protective effect of estradiol on Kupffer cell function is mediated via downregulation of TLR4-dependent p38 MAPK and NF-kappaB signaling following trauma-hemorrhage, which prevents the systemic release of cytokines.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Hormone antagonist therapy for estrogen receptor positive (ER+) breast cancer patients post radical surgery and radiation therapy has a poor prognosis and also causes bone loss. ...1α,25-dihydroxyvitamin D(3) 1α,25(OH)(2)D(3) is a potent antitumor agent in pre-clinical studies, but caused hypercalcemia when its effective antitumor doses were used. Therefore, we investigated the effects of a less-calcemic 1α,25(OH)(2)D(3) analog, 19-nor-2α-(3-hydroxypropyl)-1α,25-dihydroxyvitamin D(3 )(MART-10), on ER+MCF-7 cells. We demonstrate that MART-10 is 500- to 1000-fold more potent than 1α,25(OH)(2)D(3) in inhibiting cell growth in a dose- and time-dependent manner. MART-10 is also much more potent in arresting MCF-7cell cycle progression at G(0)/G(1) phase as compared to 1α,25(OH)(2)D(3), possibly mediated by a greater induction of p21 and p27 expression. Moreover, MART-10 is more active than 1α,25(OH)(2)D(3) in causing cell apoptosis, likely through a higher BAX/Bcl expression ratio and the subsequent cytochrome C release from mitochondria to cytosol. Based on our in vitro findings, MART-10 could be a promising vitamin D analog for the potential treatment of breast cancer, for example, ER+ patients, to decrease the tumor relapse rate and the side effect on bone caused by antihormone regimens. Thus, further in vivo animal study is warranted.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK, VSZLJ
Extracellular signal-regulated protein kinase (ERK) is known to be involved in pro-inflammatory and chemotactic events in response to injury. The aim of this study is to elucidate whether ERK plays ...any role in 17beta-estradiol (E2)-mediated attenuation of lung injury and pro-inflammatory mediators after trauma-hemorrhage.
Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure approximately 40 mm Hg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle (cyclodextrin), E2 (1 mg/kg body weight BW), or the ERK inhibitor PD98059 (2 mg/kg BW). At 2 h after sham operation or trauma-hemorrhage, various parameters were measured.
Trauma-hemorrhage led to a significant increase in lung ERK phosphorylation, which was associated with increased lung myeloperoxidase activity, wet-to-dry weight ratio, interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, intercellular adhesion molecule (ICAM)-1, cytokine-induced neutrophil chemoattractant (CINC)-1, and macrophage inflammatory protein-2 levels. Circulatory IL-6, TNF-alpha, and lactate levels were also increased after trauma-hemorrhage compared with shams. Administration of E2 or ERK inhibitor PD98059 after trauma-hemorrhage attenuated the trauma-hemorrhage-induced increase in lung injury markers, ERK phosphorylation and cytokines/chemokines, ICAM-1 production, as well as circulatory cytokines and lactate levels.
These results collectively suggest that the salutary effects of E2 on the lung after trauma-hemorrhage are mediated via an ERK pathway and subsequent downregulation of pro-inflammatory mediator production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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