Caspase inhibition reduces cardiac myocyte dyshomeostasis and improves cardiac contractile function after major burn injury

Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390-9160, USA.
Journal of Applied Physiology (Impact Factor: 3.06). 08/2007; 103(1):323-30. DOI: 10.1152/japplphysiol.01255.2006
Source: PubMed

ABSTRACT In the heart, thermal injury activates a group of intracellular cysteine proteases known as caspases, which have been suggested to contribute to myocyte inflammation and dyshomeostasis. In this study, Sprague-Dawley rats were given either a third-degree burn over 40% total body surface area plus conventional fluid resuscitation or sham burn injury. Experimental groups included 1) sham burn given vehicle, 400 microl DMSO; 2) sham burn given Q-VD-OPh (6 mg/kg), a highly specific and stable caspase inhibitor, 24 and 1 h prior to sham burn; 3) burn given vehicle, DMSO as above; 4) burn given Q-VD-OPh (6 mg/kg) 24 and 1 h prior to burn. Twenty-four hours postburn, hearts were harvested and studied with regard to myocardial intracellular sodium concentration, intracellular pH, ATP, and phosphocreatine (23Na/31P nuclear magnetic resonance); myocardial caspase-1, -3,and -8 expression; myocyte Na+ (fluorescent indicator, sodium-binding benzofurzan isophthalate); myocyte secretion of TNF-alpha, IL-1beta, IL-6, and IL-10; and myocardial performance (Langendorff). Burn injury treated with vehicle alone produced increased myocardial expression of caspase-1, -3, and -8, myocyte Na+ loading, cytokine secretion, and myocardial contractile depression; cellular pH, ATP, and phosphocreatine were stable. Q-VD-OPh treatment in burned rats attenuated myocardial caspase expression, prevented burn-related myocardial Na+ loading, attenuated myocyte cytokine responses, and improved myocardial contraction and relaxation. The present data suggest that signaling through myocardial caspases plays a pivotal role in burn-related myocyte sodium dyshomeostasis and myocyte inflammation, perhaps contributing to burn-related contractile dysfunction.

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    • "Because local accumulation of cytokines may induce apoptosis and significantly extend the initial injury, we also wanted to clarify whether the ability of gelsolin to down-regulate cytokine signaling could lead to decreased activation of apoptotic proteins in brain. Previous investigations have documented that severe burn injury is associated with a significant increase in apoptosis in remote organs [30,49,50] including brain [47]. A number of markers such as S100B and NSE can serve as general markers of brain injury. "
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    ABSTRACT: Burn survivors develop long-term cognitive impairment with increased inflammation and apoptosis in the brain. Gelsolin, an actin-binding protein with capping and severing activities, plays a crucial role in the septic response. We investigated if gelsolin infusion could attenuate neural damage in burned mice. Mice with 15% total body surface area burns were injected intravenously with bovine serum albumin as placebo (2 mg/kg), or with low (2 mg/kg) or high doses (20 mg/kg) of gelsolin. Samples were harvested at 8, 24, 48 and 72 hours postburn. The immune function of splenic T cells was analyzed. Cerebral pathology was examined by hematoxylin/eosin staining, while activated glial cells and infiltrating leukocytes were detected by immunohistochemistry. Cerebral cytokine mRNAs were further assessed by quantitative real-time PCR, while apoptosis was evaluated by caspase-3. Neural damage was determined using enzyme-linked immunosorbent assay of neuron-specific enolase (NSE) and soluble protein-100 (S-100). Finally, cerebral phospho-ERK expression was measured by western blot. Gelsolin significantly improved the outcomes of mice following major burns in a dose-dependent manner. The survival rate was improved by high dose gelsolin treatment compared with the placebo group (56.67% vs. 30%). Although there was no significant improvement in outcome in mice receiving low dose gelsolin (30%), survival time was prolonged against the placebo control (43.1 ± 4.5 h vs. 35.5 ± 5.0 h; P < 0.05). Burn-induced T cell suppression was greatly alleviated by high dose gelsolin treatment. Concurrently, cerebral abnormalities were greatly ameliorated as shown by reduced NSE and S-100 content of brain, decreased cytokine mRNA expressions, suppressed microglial activation, and enhanced infiltration of CD11b+ and CD45+ cells into the brain. Furthermore, the elevated caspase-3 activity seen following burn injury was remarkably reduced by high dose gelsolin treatment along with down-regulation of phospho-ERK expression. Exogenous gelsolin infusion improves survival of mice following major burn injury by partially attenuating inflammation and apoptosis in brain, and by enhancing peripheral T lymphocyte function as well. These data suggest a novel and effective strategy to combat excessive neuroinflammation and to preserve cognition in the setting of major burns.
    Journal of Neuroinflammation 09/2011; 8(1):118. DOI:10.1186/1742-2094-8-118 · 5.41 Impact Factor
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    • "Hence, the results of the present study strengthened the contention that C-3 inhibition plays a beneficial role in the improvement of contractile proteins. Elevated C-3 associated with cardiac dysfunction has been observed in burn, endotoxin and sepsis-related pathologies (Lancel et al., 2005; Carlson et al., 2007; Chopra and Sharma, 2007a,b; 2009). However, it is still unclear how C-3 regulates contractile dysfunction at the cellular or organ level. "
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    ABSTRACT: The present study tested the hypothesis that selective caspase-3 (C-3) knock-out would regulate the contractile actions of noradrenaline (NA) in the dysfunction of adult rat ventricular myocytes (ARVMs) induced by sepsis. Here, we have studied the contractile response of ARVMs, transfected with C-3 small interfering RNA (C-3 siRNA), to NA. Single ARVMs were isolated from the hearts of male Sprague-Dawley rats 3 days after induction of sepsis, and from sham-treated rats. The sham and septic ARVMs were treated with NA (10 microM) alone or after transfection with C-3 siRNA or non-silencing RNA (2 microM). Mechanical properties were measured digitally, and immunoblotting and immunocytochemical analyses were carried out. The NA-induced increase in peak shortening (PS) was less in septic ARVMs and transfection with C-3 siRNA produced a significant increase in this PS. Immunocytochemical and immunoblot analyses revealed that NA exacerbated sepsis-induced up-regulation of C-3. Transfection of septic ARVMs with C-3 siRNA exhibited a decreased expression of C-3 fluorescence after NA. In septic ARVMs, we also observed a down-regulation of contractile proteins (alpha-actin, myosin light chain-1 and tropomyosin) along with DNA damage. Transfection of septic ARVMs with C-3 siRNA produced an increase in the expression of contractile proteins, and a decrease in DNA damage. These data suggest that C-3 knock-down improved the loss of contractile response to NA in septic ARVMs, suggesting that C-3 regulated contractile dysfunction induced by sepsis in ARVMs.
    British Journal of Pharmacology 03/2010; 160(1):93-100. DOI:10.1111/j.1476-5381.2010.00686.x · 4.84 Impact Factor
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    ABSTRACT: The objective is to determine if Hsp70 is involved in the mechanism by which serum from burn rats induces apoptosis of cardiomyocytes. Cardiomyocytes in primary culture were assigned to the following groups: normal controls, normal rat serum, burn serum, burn serum plus empty vector control, and burn serum plus Hsp70 transfection. Each group, except normal controls, was cultured with the corresponding serum for 2 hours. The empty vector controls and the Hsp70 groups were transfected, respectively, with the empty vector or pcDNA3.1-Hsp70 recombinant plasmid 36 hours previously. Hsp70 protein levels were assessed by Western blot. Apoptotic cells were counted after Hoechst 33258 staining. Apoptosis of cardiomyocytes was also detected by the presence of "ladder" bands in agarose gels following electrophoresis of extracted DNA. Activation of caspase-3, -8, and -9 and Bid cleavage were assessed by Western blot. Hsp70 overexpression inhibited burn serum-induced apoptosis of cardiomyocytes; and burn serum-induced activation of caspases-3, -8, and -9; and Bid cleavage into tBid. Hsp70 inhibits burn serum-induced apoptosis by interfering with death receptor and mitochondrial pathways.
    Journal of burn care & research: official publication of the American Burn Association 04/2008; 29(3):512-8. DOI:10.1097/BCR.0b013e318171089a · 1.43 Impact Factor
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