Hemorrhagic shock induces differential gene expression and apoptosis in mouse liver

MKK4 Knockdown Plays a Protective Role in Hemorrhagic Shock-Induced Liver Injury through the JNK Pathway

Hemorrhagic shock (HS) triggers tissue hypoxia and organ failure during severe blood loss, and the liver is sensitive to HS. Mitogen-activated protein kinase kinase 4 (MKK4) activates the c-Jun NH2-terminal kinase (JNK) pathway, and its expression is upregulated in the serum of HS patients and mouse livers at 1 h post-HS. However, the function of MKK4 in HS-induced liver injury is unclear. The role of MKK4 was investigated in vivo using rat models of HS. Before HS, lentivirus harboring shRNA against MKK4 was injected into rats via the tail vein to knock down MKK4 expression. HS was induced by bloodletting via intubation of the femoral artery followed by resuscitation. The results showed that MKK4 knockdown reduced HS-induced apoptosis in the liver by decreasing Bax expression and the cleavage of caspase 3 and promoting Bcl-2 expression. Moreover, the generation of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) in the liver was promoted, while superoxide dismutase (SOD) activity was inhibited by HS. However, the effect of HS on oxidative stress was abrogated by MKK4 knockdown. Furthermore, MKK4 knockdown restored MMP and complex I and complex III activities and promoted ATP production, suggesting that HS-induced mitochondrial dysfunction in the liver was ameliorated by MKK4 knockdown. The inhibitory effect of MKK4 knockdown on the phosphorylation and activation of the JNK/c-Jun pathway was confirmed. Overall, MKK4 knockdown may suppress oxidative stress and subsequent apoptosis and improve mitochondrial function in the liver upon HS by inhibiting the JNK pathway. The MKK4/JNK axis was shown to be a therapeutic target for HS-induced liver injury in this study.

Sulfide exposure results in enhanced sqr transcription through upregulating the expression and activation of HSF1 in echiuran worm Urechis unicinctus

Sulfide is a natural, widely distributed, poisonous substance. Sulfide: quinone oxidoreductase (SQR) is responsible for the initial oxidation of sulfide in mitochondria. To study transcriptional regulation of sqr after sulfide exposure, a 2.6-kb sqr upstream sequence from echiuran worm Urechis unicinctus was cloned by genome walking. Bioinformatics analysis showed 3 heat shock elements (HSEs) in proximal promoter region of the sqr upstream sequence. Moreover, an Hsf1 cDNA in U. unicinctus (UuHsf1) was isolated with a full-length sequence of 2334 bp and its polyclonal antibody was prepared using U. unicinctus HSF1 (UuHSF1) expressed prokaryotically with whole sequence of its open reading frame (ORF). In vivo ChIP and in vitro EMSA assays revealed UuHSF1 could interact with the sqr proximal promoter region. Transient transfection and mutation assays indicated that UuHSF1 bound specifically to HSE (-155bp to -143bp) and enhanced the transcription of sqr. Furthermore, sulfide treatment experiments demonstrated that sulfide could increase the expression of HSF1 protein, and induce trimerization of the protein which binds to HSEs and then activate sqr transcription. Quantitative real-time PCR analysis revealed sqr mRNA level increased significantly after U. unicinctus was exposed to sulfide for 6h, which corresponded to content changes of both trimeric HSF1 and HSF1-HSE complex. We concluded that UuHSF1 is a transcription factor of sqr and sulfide could induce sqr transcription by upregulating the expression and activation of HSF1 in U. unicinctus exposed to sulfide.

Docosahexaenoic acid inhibits inflammation via free fatty acid receptor FFA4, disruption of TAB2 interaction with TAK1/TAB1 and downregulation of ERK-dependent Egr-1 expression in EA.hy926 cells

SCOPE

Inflammation is intimately associated with many cardiovascular events and docosahexaenoic acid (DHA) has been shown to protect against CVD. Egr-1 has emerged as a key regulator in the development of atherosclerosis. Free fatty acid receptor 4 (FFA4) is an n-3 FA membrane receptor. Tumor necrosis factor alpha (TNF-α) is an inflammatory mediator and transforming growth factor-β-activated kinase 1 (TAK1) is essential in the TNF-α-mediated activation of NF-κB. We examined the mechanisms underlying DHA inhibition of inflammation in human EA.hy926 cells.

METHODS AND RESULTS

TNF-α markedly induced the interaction between TAK1 binding protein (TAB) 2 and TAK1/TAB1, the phosphorylation of ERK, p38 MAPK and Akt, the expression of Egr-1 and ICAM-1, and HL-60 (monocyte-like) cell adhesion. Pretreatment with DHA attenuated TNF-α-induced phosphorylation of ERK, expression of Egr-1 and ICAM-1 and HL-60 cell adhesion. Transfection with siFFA4 reversed the DHA-mediated inhibition of TNF-α-induced Egr-1 and ICAM-1 expression, HL-60 cell adhesion and NF-κB and DNA-binding activity.

CONCLUSION

Our results suggest that the anti-inflammatory effect of DHA on the endothelium is at least partially linked to FFA4, disruption of TAB2 interaction with TAK1/TAB1 and downregulation of ERK-dependent Egr-1 and ICAM-1 expression, which leads to less HL-60 cell adhesion to TNF-α-stimulated EA.hy926 cells.

1H NMR-metabolomics: can they be a useful tool in our understanding of cardiac arrest?

OBJECTIVE

This review focuses on the presentation of the emerging technology of metabolomics, a promising tool for the detection of identifying the unrevealed biological pathways that lead to cardiac arrest.

DATA SOURCES

The electronic bases of PubMed, Scopus, and EMBASE were searched. Research terms were identified using the MESH database and were combined thereafter. Initial search terms were "cardiac arrest", "cardiopulmonary resuscitation", "post-cardiac arrest syndrome" combined with "metabolomics".

RESULTS

Metabolomics allow the monitoring of hundreds of metabolites from tissues or body fluids and already influence research in the field of cardiac metabolism. This approach has elucidated several pathophysiological mechanisms and identified profiles of metabolic changes that can be used to follow the disease processes occurring in the peri-arrest period. This can be achieved through leveraging the strengths of unbiased metabolome-wide scans, which include thousands of final downstream products of gene transcription, enzyme activity and metabolic products of extraneously administered substances, in order to identify a metabolomic fingerprint associated with an increased risk of cardiac arrest.

CONCLUSION

Although this technology is still under development, metabolomics is a promising tool for elucidating biological pathways and discovering clinical biomarkers, strengthening the efforts for optimizing both the prevention and treatment of cardiac arrest.

Sanguinarine induces apoptosis in human colorectal cancer HCT-116 cells through ROS-mediated Egr-1 activation and mitochondrial dysfunction

We examined the effects of sanguinarine, a benzophenanthridine alkaloid, on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death in a human colorectal cancer HCT-116 cell line. Sanguinarine generated ROS, which was followed by a decrease in the mitochondrial membrane potential (MMP), the activation of caspase-9 and -3, and the down-regulation of anti-apoptotic proteins, such as Bcl2, XIAP and cIAP-1. Sanguinarine also promoted the activation of caspase-8 and truncation of Bid (tBid). However, the quenching of ROS generation by N-acetyl-l-cysteine, a scavenger of ROS, reversed the sanguinarine-induced apoptosis effects via inhibition of the MMP collapse, tBid expression, and activation of caspases. Sanguinarine also markedly induced the expression of the early growth response gene-1 (Egr-1) during the early period, after which expression level was decreased. In addition, HCT-116 cells transfected with Egr-1 siRNA displayed significant blockage of sanguinarine-induced apoptotic activity in a ROS-dependent manner. These observations clearly indicate that ROS, which are key mediators of Egr-1 activation and MMP collapse, are involved in the early molecular events in the sanguinarine-induced apoptotic pathway acting in HCT-116 cells.

Modulation of the unfolded protein response during hepatocyte and cardiomyocyte apoptosis in trauma/hemorrhagic shock

Trauma with hemorrhagic shock (T/HS), has been shown to result in liver injury marked by hepatocyte apoptosis and heart failure marked by cardiomyocyte apoptosis, both of which we have shown to be prevented by IL-6 administration at resuscitation, and Stat3 largely mediated this. As specific mediators have not been delineated, we investigated the unfolded protein response (UPR), which, with marked activation, can lead to apoptosis. Prior studies of hepatic and cardiac injury examined limited repertoires of UPR elements, making it difficult to assess the role of the UPR in T/HS. This study describes the first global examination of the UPR transcriptome in the liver and heart following T/HS, demonstrating organ-specific UPR transcriptome changes. The non-canonical UPR chaperone, Hsp70, was most dysregulated following T/HS and may contribute to hepatocyte protection via an IL-6-mediated pathway, identifying a potential new therapeutic strategy to prevent hepatocyte death and organ dysfunction in T/HS.

Glutamine-mediated dual regulation of heat shock transcription factor-1 activation and expression

BACKGROUND

Regulation of transcriptional activity of heat shock factor-1 (HSF1) is widely thought to be the main point of control for heat shock protein (Hsp) expression.

RESULTS

Glutamine increases Hsf1 gene transcription in a C/EBPβ-dependent manner and up-regulates HSF1 activity.

CONCLUSION

Glutamine is an activator for both HSF1 expression and transactivation.

SIGNIFICANCE

Glutamine-induced HSF1 expression provides a novel mechanistic frame for HSF1-Hsp axis regulation. Heat shock transcription factor-1 (HSF1) is the master regulator for cytoprotective heat shock protein (Hsp) expression. It is widely thought that HSF1 expression is non-inducible, and thus the key control point of Hsp expression is regulation of the transactivation activity of HSF1. How HSF1 expression is regulated remains unknown. Herein we demonstrate that glutamine (Gln), a preferred fuel substrate for the gut, enhanced Hsp expression both in rat colonic epithelium in vivo and in cultured non-transformed young adult mouse colonic epithelial cells. This was associated with up-regulation of the transactivation activity of HSF1 via increased HSF1 trimerization, nuclear localization, DNA binding, and relative abundance of activating phosphorylation at Ser-230 of HSF1. More intriguingly, Gln enhanced HSF1 protein and mRNA expression and Hsf1 gene promoter activity. Within the -281/-200 region of the Hsf1 promoter, deletion of the putative CCAAT enhancer-binding protein (C/EBP) binding site abolished the HSF1 response to Gln. C/EBPβ was further shown to bind to this 82-bp sequence both in vitro and in vivo. Gln availability strikingly altered the ratio of C/EBPβ inhibitory and active isoforms, i.e. liver-enriched inhibitory protein and liver-enriched activating protein. Liver-enriched inhibitory protein and liver-enriched activating protein were further shown to be an independent repressor and activator, respectively, for Hsf1 gene transcription, and the relative abundance of these two C/EBPβ isoforms was demonstrated to determine Hsf1 transcription. We show for the first time that Gln not only enhances the transactivation of HSF1 but also induces Hsf1 expression by activating its transcription in a C/EBPβ-dependent manner.

Redox-mediated programed death of myocardial cells after cardiac arrest and cardiopulmonary resuscitation

Besides the fact that prolonged whole-body ischemia causes tissue and organ injury during cardiac arrest, additional damage occurs after the restoration of spontaneous circulation, during which the reperfusion activates a host of intracellular responses. These responses may lead to an increased threshold of oxidant-mediated injury and redox-mediated programed cell death in the stunned myocardium. The aim of this article is to summarize the major intracellular responses occurring from the onset of cardiac arrest until the post-resuscitation period that may lead to redox-mediated programed death of myocardial cells.

IL-6-mediated activation of Stat3α prevents trauma/hemorrhagic shock-induced liver inflammation

Trauma complicated by hemorrhagic shock (T/HS) is the leading cause of morbidity and mortality in the United States for individuals under the age of 44 years. Initial survivors are susceptible to developing multiple organ failure (MOF), which is thought to be caused, at least in part, by excessive or maladaptive activation of inflammatory pathways. We previously demonstrated in rodents that T/HS results in liver injury that can be prevented by IL-6 administration at the start of resuscitation; however, the contribution of the severity of HS to the extent of liver injury, whether or not resuscitation is required, and the mechanism(s) for the IL-6 protective effect have not been reported. In the experiments described here, we demonstrated that the extent of liver inflammation induced by T/HS depends on the duration of hypotension and requires resuscitation. We established that IL-6 administration at the start of resuscitation is capable of completely reversing liver inflammation and is associated with increased Stat3 activation. Global assessment of the livers showed that the main effect of IL-6 was to normalize the T/HS-induced inflammation transcriptome. Pharmacological inhibition of Stat3 activity within the liver blocked the ability of IL-6 to prevent liver inflammation and to normalize the T/HS-induced liver inflammation transcriptome. Genetic deletion of a Stat3β, a naturally occurring, dominant-negative isoform of the Stat3, attenuated T/HS-induced liver inflammation, confirming a role for Stat3, especially Stat3α, in preventing T/HS-mediated liver inflammation. Thus, T/HS-induced liver inflammation depends on the duration of hypotension and requires resuscitation; IL-6 administration at the start of resuscitation reverses T/HS-induced liver inflammation, through activation of Stat3α, which normalized the T/HS-induced liver inflammation transcriptome.

Plant polyphenols attenuate hepatic injury after hemorrhage/resuscitation by inhibition of apoptosis, oxidative stress, and inflammation via NF-kappaB in rats

PURPOSE

Oxidative stress and inflammation contribute to hepatic injury after hemorrhage/resuscitation (H/R). Natural plant polyphenols, i.e., green tea extract (GTE) possess high anti-oxidant and anti-inflammatory activities in various models of acute inflammation. However, possible protective effects and feasible mechanisms by which plant polyphenols modulate pro-inflammatory, apoptotic, and oxidant signaling after H/R in the liver remain unknown. Therefore, we investigated the effects of GTE and its impact on the activation of NF-kappaB in the pathogenesis of hepatic injury induced by H/R.

METHODS

Twenty-four female LEWIS rats (180-250 g) were fed a standard chow (ctrl) or a diet containing 0.1% polyphenolic extracts (GTE) from Camellia sinensis starting 5 days before H/R. Rats were hemorrhaged to a mean arterial pressure of 30 ± 2 mmHg for 60 min and resuscitated (H/R and GTE H/R groups). Control groups (sham, ctrl, and GTE) underwent surgical procedures without H/R. Two hours after resuscitation, tissues were harvested.

RESULTS

Plasma alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) increased 3.5-fold and fourfold, respectively, in vehicle-treated rats as compared to GTE-fed rats. Histopathological analysis revealed significantly decreased hepatic necrosis and apoptosis in GTE-fed rats after H/R. Real-time PCR showed that GTE diminished gene expression of pro-apoptotic caspase-8 and Bax, while anti-apoptotic Bcl-2 was increased after H/R. Hepatic oxidative (4-hydroxynonenal) and nitrosative (3-nitrotyrosine) stress as well as systemic IL-6 level and hepatic IL-6 mRNA were markedly reduced in GTE-fed rats compared with controls after H/R. Plant polyphenols also decreased the activation of both JNK and NFκB.

CONCLUSIONS

Taken together, GTE application blunts hepatic damage, apoptotic, oxidative, and pro-inflammatory changes after H/R. These results underline the important roles of JNK and NF-kappaB in inflammatory processes after H/R and the beneficial impact of plant polyphenols in preventing their activation.

Apoptosis and haemorrhagic shock

Abstract

This is a review paper that provides an overview of current information on programmed cell death in haemorrhagic shock, including the identification of different molecular receptor signals. A PubMed search for all dates was undertaken using the search terms apoptosis, trauma and haemorrhagic shock. Original research, sentinel and review papers from peer-reviewed journals were included for identification of key concepts. Haemorrhagic shock remains a primary cause of death in civilian and military trauma. Apoptosis is accelerated following haemorrhagic shock. Many methods are used to detect and quantify apoptosis. Fluid resuscitation regimens vary in their effect on the extent of apoptosis. Investigators are examining the effects of haemorrhagic shock and fluid resuscitation on apoptotic signalling pathways. Molecular information is becoming available and being applied to the care of patients experiencing haemorrhagic shock, making it essential for nurses and other health care providers to consider the mechanisms and consequences of apoptosis.

Hepatoprotection and lethality rescue by histone deacetylase inhibitor valproic acid in fatal hemorrhagic shock

BACKGROUND

Pharmacological histone deacetylase (HDAC) inhibitors, such as known anticonvulsant valproic acid (VPA), demonstrate cytoprotective effects and increase acetylation of nuclear histones, promoting transcriptional activation of deregulated genes. Therefore, we examined protective effects of VPA administration in lethal hemorrhage and analyzed the patterns of hepatic histone acetylation.

METHODS

Male Wistar Kyoto rats were pretreated with VPA (n = 10) and 2-methyl-2-pentenoic acid (2M2P), structural VPA analog with limited HDAC inhibiting activity (2M2P; n = 8), at 300 mg/kg/dose, administered subcutaneously, 24 hour and immediately before lethal, if untreated, hemorrhage was induced by removing the 60% of total blood volume. Both drugs were dissolved in normal saline (NS) and rats pretreated with corresponding volume of NS served as control group (n = 8). Time to death, the degree of histone acetylation in liver, HDAC activity and markers of cytotoxicity (alpha-glutathione S-transferase, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and lactate), and apoptosis were analyzed.

RESULTS

VPA-pretreated animals demonstrated five-fold increase in survival duration. At 12 hours posthemorrhage, 70% (VPA) and 12% (2M2P) pretreated rats were alive versus 0% in NS group. Hyperacetylation of histones H2A, H3, and H4 indicated the presence of active genes and correlated with survival (VPA > 2M2P > NS). Hemorrhage-induced increases in lactate, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase were alleviated by VPA. Moreover, alpha-glutathione S-transferase release, indicative of liver damage, was completely abolished.

CONCLUSION

VPA offers considerable protection in severe hemorrhagic shock. The role of HDAC inhibition is suggested in mediating prosurvival actions of VPA.

Superoxide dismutase activity and malondialdehyde level in plasma and morphological evaluation of acute severe hemorrhagic shock in rats

OBJECTIVES

The aim of the study was to investigate the changes of the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in plasma and organ damage during the acute severe hemorrhagic shock (ASHS), as well as to analyze their relationship.

METHODS

Twenty male Wistar rats (230-270 g) were randomly divided into sham hemorrhage shock (SHS) group and ASHS group. Acute severe hemorrhagic shock rats were induced by drawing blood through a femoral arterial catheter for 15 minutes with the final mean arterial blood pressure decreased to 35 to 40 mm Hg. The animals were killed after the mean arterial blood pressure was maintained at this level for 1 hour. The activity of SOD and the level of MDA in plasma were measured, and pathologic changes of the major organs (heart, liver, spleen, lung, kidney, and brain) were observed by microscopy.

RESULTS

The SOD activities and MDA levels in the ASHS group both increased continuously during the whole experiment. The SOD activities and MDA levels in plasma were not significantly different between the prehemorrhagic stage of ASHS and that of SHS (P > .05). The SOD activities and MDA levels were significantly higher in the ASHS initial stage than in the prehemorrhagic stage (P < .01). Compared with the ASHS initial stage, there was a significant (P < .01) increase in SOD activities and MDA levels in the ASHS end stage. Severe microscopic injuries appeared in the major organs (heart, liver, spleen, lung, kidney, and brain) of ASHS rats.

CONCLUSION

The changes of the activity of SOD and the level of MDA in ASHS may have a positive correlation.

Hemin upregulates Egr-1 expression in vascular smooth muscle cells via reactive oxygen species ERK-1/2-Elk-1 and NF-kappaB

Reactive oxygen species (ROS) and oxidant stress are important mediators of cardiovascular pathologies including atherosclerosis. One source of ROS in the vasculature is free heme released from hemoglobin. Because Egr-1, the regulator of cell proliferation and apoptosis, is also induced by oxidant stress and is likewise implicated in atherosclerosis, we examined the regulation of Egr-1 by heme in vascular smooth muscle cells (SMCs). Hemin increased Egr-1 expression (mRNA, protein) within 30 minutes and ERK-1/2 phosphorylation and nuclear translocation within 5 minutes. Inhibiting hemin-induced ERK-1/2 activation by U0126 (MAPK-inhibitor), the antioxidant N-acetyl cysteine, the NADPH oxidase inhibitors apocynin and diphenyleneiodonium chloride, the superoxide scavenger tiron, or tricarbonyldichlororuthenium(II)-dimer (carbon-monoxide donor; CORM-2) blocked hemin-induced Egr-1 expression. Hemin activated Elk-1, SRF, and NF-kappaB and promoted their interaction with the Egr-1 promoter. Downregulating Elk-1 (via siRNA) or blocking NF-kappaB activation (via BAY-11-7082) abolished hemin induction of Egr-1. Finally, hemin-induced Egr-1 bound the promoters of tissue factor (TF), Plasminogen Activator Inhibitor (PAI)-1, and NGF-1A Binding (NAB)-2, upregulating their expression, and increased the biochemical activity of TF and PAI-1. Upregulation of Egr-1 and its target genes by heme-induced oxidant stress may be an important event in the initiation and progression of inflammatory vascular diseases such as atherosclerosis.

Identification of Expression Patterns Associated with Hemorrhage and Resuscitation: Integrated Approach to Data Analysis

BACKGROUND

Although transcriptional profiling is a well-established technique, its application to systematic studying of various biological phenomena is still limited because of problems with high-volume data analysis and interpretation. This research project's objective was to create a comprehensive summary of changes in gene expression after hemorrhagic shock (HS), reliant and impartial of multiple variables, such as resuscitation treatments, organ analyzed, and time after impact.

METHODS

Rat model of severe (40% total blood loss) HS was employed. Hemorrhagic shock was treated with 6 different resuscitation strategies: (1) racemic lactated Ringer's (DL-LR); (2) L-lactated Ringer's (L-LR); (3) ketone Ringer's (KR); (4) pyruvate Ringer's (PR); (5) 6% hetastarch (Hex); (6) 7.5% hypertonic saline (HTS). Nonresuscitated and nonhemorrhaged rats served as controls. Ketone and pyruvate Ringer solutions were identical to the lactated Ringer's solution except for equimolar substitution of lactate with beta-hydroxybutyrate and sodium pyruvate, respectively. Total RNA from liver, lung, and spleen was isolated immediately (0 hour) and 24 hour postresuscitation. Each organ, time point and treatment was profiled using individual cDNA array (1,200 genes), to produce 183 separate data files. Methods of analysis included one-way and unbalanced factorial ANOVA, Sokal-Michener average linkage clustering and contextual mapping.

RESULTS

: Unresuscitated HS produced the highest number (56) of upregulated expressions in spleen and lungs. HEX and HTS affected mostly pulmonary genes (22 and 9). Fourteen genes changed in response to combination of all three factors: treatment, organ, and time. Eighteen genes were identified as treatment-specific. Fifteen genes adjusted expression 24 hour post-treatment. The largest number of genes with altered expression (168) responded differently in all three organs. In this study 15 gene clusters were pinpointed. Contextual mapping identified novel and confirmed known pathways contributing to hemorrhage/resuscitation.

CONCLUSIONS

We have reliably identified genes and pathways that are affected by HS and are responsive to resuscitation. Gene expression in various organs is affected differentially by HS, which can be further modulated by the choice of resuscitation strategy.