SB203580, a p38 inhibitor, improved cardiac function but worsened lung injury and survival during Escherichia coli pneumonia in mice. ACTA ACUST UNITED AC. 2010;68:1317-1327. [PMID: 20068480 DOI: 10.1097/TA.0b013e3181bb9cd3]

Neuregulin‑1: An underlying protective force of cardiac dysfunction in sepsis (Review)

Neuregulin-1 (NRG-1) is a type of epidermal growth factor‑like protein primarily distributed in the nervous and cardiovascular systems. When sepsis occurs, the incidence of cardiac dysfunction in myocardial injury is high and the mechanism is complicated. It directly causes myocardial cell damage, whilst also causing damage to the structure and function of myocardial cells, weakening of endothelial function and coronary microcirculation, autonomic dysfunction, and activation of myocardial inhibitory factors. Studies investigating NRG‑1 have been performed using a variety of methods, including in vitro models, and animal and human clinical trials; however, the results are not consistent. NRG‑1/ErbBs signaling is involved in a variety of cardiac processes, from the development of the myocardium and cardiac conduction systems to the promotion of angiogenesis in cardiomyocytes, and in cardio‑protective effects during injury. NRG‑1 may exert a multifaceted cardiovascular protective effect by activating NRG‑1/ErbBs signaling and regulating multiple downstream signaling pathways, thereby improving myocardial cell dysfunction in sepsis, and protecting cardiomyocytes and endothelial cells. It may alleviate myocardial microvascular endothelial injury in sepsis; its anti‑inflammatory effects inhibit the production of myocardial inhibitory factors in sepsis, improve myocardial ischemia, decrease oxidative stress, regulate the disruption to the homeostasis of the autonomic nervous system, improve diastolic function, and offer protective effects at multiple target sites. As the mechanism of action of NRG‑1 intersects with the pathways involved in the pathogenesis of sepsis, it may be applicable as a treatment strategy to numerous pathological processes in sepsis.

MKP-1 Modulates Mitochondrial Transcription Factors, Oxidative Phosphorylation, and Glycolysis

Sepsis is the leading cause of death in the world. Recent reports suggest that in response to sepsis, metabolism of macrophages switches from oxidative phosphorylation to aerobic glycolysis. MAPK phosphatase (MKP)–1 (also known as DUSP1) localized in the nucleus and preferentially dephosphorylates p38 and JNK. MKP-1 controls the expression of numerous inflammatory genes and transcription factors, thereby regulating innate and adaptive immunity. MKP-1–deficient animals exhibit aberrant metabolic responses following bacterial infections with a markedly increased mortality in response to sepsis. Because metabolic reprogramming modulates immune responses to TLR-4 activation, we investigated the effect of MKP-1 deficiency on mitochondrial electron transport chains involved in oxidative phosphorylation and transcription factors regulating mitochondrial biogenesis. Mitochondrial biogenesis is regulated by three nuclear-encoded proteins, including transcription factor A (TFAM), nuclear respiratory factors (NRF-1), and peroxisome proliferator–activated receptor γ coactivator-1-α (PGC-1α). We show that MKP-1–deficient mice/ macrophages exhibit, at baseline, higher expression of oxidative phosphorylation, TFAM, PGC-1α, and NRF-1 associated with increased respiration and production of reactive oxygen species as compared with wild-type mice. Surprisingly, MKP-1–deficient mice/macrophages responded to Escherichia coli sepsis or LPS with an impaired metabolic switch; despite enhanced glycolysis, a preserved mitochondrial function and biogenesis are exhibited. Furthermore, inhibition of p38 MAPK had no significant effect on TFAM and NRF-1 either in MKP-1–deficient macrophages or in wild-type macrophages. These findings support the conclusion that MKP-1 plays an important role in regulating proteins involved in glycolysis and oxidative phosphorylation and modulates expression of mitochondrial transcription factors.

Molecular mechanisms involved in drug-induced liver injury caused by urate-lowering Chinese herbs: A network pharmacology study and biology experiments

As an important part of the comprehensive treatment methods, the urate-lowering Chinese herbs could provide favorable clinical effects on hyperuricemia in its ability to invigorate spleen and remove dampness. Owing to the long-term duration, it brought up the potential adverse reactions (ADRs) and concerns about the drug-induced liver injury from these herbs. To address this problem, the bioinformatics approaches which combined the network pharmacology, computer simulation and molecular biology experiments were undertaken to elucidate the underlying drug-induced liver injury molecular mechanisms of urate-lowering Chinese herbs. Several electronic databases were searched to identify the potential liver injury compounds in published research. Then, the putative target profile of liver injury was predicted, and the interaction network was constructed based on the links between the compounds, corresponding targets and core pathways. Accordingly, the molecular docking simulation was performed to recognize the representative compounds with hepatotoxicity. Finally, the cell experiments were conducted to investigate the biochemical indicators and expression of the crucial protein that were closely associated with liver injury. In conclusion, the current research revealed that the compounds with potential liver injury including diosgenin, baicalin, saikosaponin D, tetrandrine, rutaecarpine and evodiamine from urate-lowering Chinese herbs, could lead to decline the survival rate of L-02 cell, increase the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in cell-culture medium, enhance the expression of p-p38/p38, while the p38 inhibitor could achieve the trend of regulating and controlling liver injury. These research findings bring further support to the growing evidence that the mechanism of the liver injury induced by the compounds from urate-lowering Chinese herbs may be associated with the activation of p38α.

Immunothrombotic Activity of Damage-Associated Molecular Patterns and Extracellular Vesicles in Secondary Organ Failure Induced by Trauma and Sterile Insults

Despite significant improvements in injury prevention and emergency response, injury-related death and morbidity continues to increase in the US and worldwide. Patients with trauma, invasive operations, anti-cancer treatment, and organ transplantation produce a host of danger signals and high levels of pro-inflammatory and pro-thrombotic mediators, such as damage-associated molecular patterns (DAMPs) and extracellular vesicles (EVs). DAMPs (e.g., nucleic acids, histone, high-mobility group box 1 protein, and S100) are molecules released from injured, stressed, or activated cells that act as endogenous ligands of innate immune receptors, whereas EVs (e.g., microparticle and exosome) are membranous vesicles budding off from plasma membranes and act as messengers between cells. DAMPs and EVs can stimulate multiple innate immune signaling pathways and coagulation cascades, and uncontrolled DAMP and EV production causes systemic inflammatory and thrombotic complications and secondary organ failure (SOF). Thus, DAMPs and EVs represent potential therapeutic targets and diagnostic biomarkers for SOF. High plasma levels of DAMPs and EVs have been positively correlated with mortality and morbidity of patients or animals with trauma or surgical insults. Blocking or neutralizing DAMPs using antibodies or small molecules has been demonstrated to ameliorate sepsis and SOF in animal models. Furthermore, a membrane immobilized with nucleic acid-binding polymers captured and removed multiple DAMPs and EVs from extracellular fluids, thereby preventing the onset of DAMP- and EV-induced inflammatory and thrombotic complications in vitro and in vivo. In this review, we will summarize the current state of knowledge of DAMPs, EVs, and SOF and discuss potential therapeutics and preventive intervention for organ failure secondary to trauma, surgery, anti-cancer therapy, and allogeneic transplantation.

The role of β-adrenergic receptors and p38MAPK signaling pathways in physiological processes of cardiosphere-derived cells

The effects of β adrenergic receptors (β-ARs) and p38 mitogen-activated protein kinases (MAPK) pathways on cardiosphere-derived cells (CDCs) are largely unknown. This study aimed to investigate the roles of β-ARs and p38MAPK pathways on the proliferation, apoptosis, and differentiation capacity of CDCs. The CDCs were treated with β1-AR blocker (Met group), β2-AR antagonist (ICI group), and p38MAPK inhibitor (SB group), non-selective β-AR blocker (PRO group), and β-AR agonist (ISO group). The viability, apoptotic rate and differentiation status of CDCs were determined by MST-1 assay, flow cytometery, and Western blot, respectively. The CDCs viability significantly reduced in ICI group (all P < 0.05), and SB group had a significant high viability after 48 h treatment (P < 0.05). Compared with control group, all treated groups had a low apoptotic rate. After treatment for 72 h, ISO treatment elevated the expression of Nkx2.5, and could partially or fully attenuate the inhibitory effects of β-AR antagonists and/or p38MAPK inhibitor. A similar overall trend of protein expression levels among all groups could be observed between protein pairs of cTnT and β1-AR as well as c-Kit and β2-AR, respectively. These results suggested that β-ARs and p38MAPK signaling pathways play crucial roles in the proliferation and differentiation of CDCs. Our findings should be helpful for better understanding the molecular mechanism underlying the physiological processes of CDCs.

CCL3 promotes angiogenesis by dysregulation of miR-374b/ VEGF-A axis in human osteosarcoma cells

Osteosarcoma is the most frequent bone tumor, characterized by a high metastatic potential. However, the crosstalk between chemokine (C-C motif) ligand 3 (CCL3), which facilitates tumor progression and metastasis. Vascular endothelial growth factor-A (VEGF-A), an angiogenesis inducer and a highly specific mitogen for endothelial cells, has not been well explored in human osteosarcoma. Here we demonstrate the correlation of CCL3 and VEGF-A expressions, quantified by immunohistochemistry, with the tumor stage of human osteosarcoma tissues. Furthermore, CCL3 promotes VEGF-A expression in human osteosarcoma cells that subsequently induces human endothelial progenitor cell (EPC) migration and tube formation. Phosphorylation of JNK, ERK, and p38 was found after CCL3 stimulation. In addition, JNK, ERK, and p38 inhibitors also abolished CCL3-induced VEGF-A expression and angiogenesis. We noted that CCL3 reduces the expression of miR-374b and miR-374b mimic by reversing CCL3-promoted VEGF-A expression and angiogenesis in vitro and in vivo. This study shows that CCL3 promotes VEGF-A expression and angiogenesis in human osteosarcoma cells by down-regulating miR-374b expression via JNK, ERK, and p38 signaling pathways. Thus, CCL3 may be a new molecular therapeutic target in osteosarcoma angiogenesis and metastasis.

Potential therapeutic targets for inflammation in toll-like receptor 4 (TLR4)-mediated signaling pathways

Inflammation is set off when innate immune cells detect infection or tissue injury. Tight control of the severity, duration, and location of inflammation is an absolute requirement for an appropriate balance between clearance of injured tissue and pathogens versus damage to host cells. Impeding the risk associated with the imbalance in the inflammatory response requires precise identification of potential therapeutic targets involved in provoking the inflammation. Toll-like receptors (TLRs) primarily known for the pathogen recognition and subsequent immune responses are being investigated for their pathogenic role in various chronic diseases. A mammalian homologue of Drosophila Toll receptor 4 (TLR4) was shown to induce the expression of genes involved in inflammatory responses. Signaling pathways via TLR4 activate various transcription factors like Nuclear factor kappa-light-chain-enhancer (NF-κB), activator protein 1 (AP1), Signal Transducers and Activators of Transcription family of transcription factors (STAT1) and Interferon regulatory factors (IRF's), which are the key players regulating the inflammatory response. Inhibition of these targets and their upstream signaling molecules provides a potential therapeutic approach to treat inflammatory diseases. Here we review the therapeutic targets involved in TLR-4 signaling pathways that are critical for suppressing chronic inflammatory disorders.

Bacillus anthracis edema but not lethal toxin challenge in rats is associated with depressed myocardial function in hearts isolated and tested in a Langendorff system

Although direct myocardial depression has been implicated in the lethal effects of Bacillus anthracis lethal toxin (LT), in hearts isolated from healthy rats and perfused under constant pressure, neither LT or edema toxin (ET) in typically lethal concentrations depressed myocardial function. In the present study, we challenged rats with LT and ET and performed in vivo and ex vivo heart measures. Sprague-Dawley rats infused over 24 h with LT (n = 94), ET (n = 99), or diluent (controls; n = 50) were studied at 8, 24, or 48 h. Compared with control rats (all survived), survival rates with LT (56.1%) and ET (37.3%) were reduced (P < 0.0001) similarly (P = 0.66 for LT vs. ET). LT decreased mean arterial blood pressure from 12 to 20 h (P ≤ 0.05), whereas ET decreased it progressively throughout (P < 0.05). On echocardiography, LT decreased left ventricular (LV) ejection fraction at 8 and 48 h but increased it at 24 h and decreased cardiac output (P ≤ 0.05 for the time interaction or averaged over time). ET decreased systolic and diastolic volumes and increased LV ejection fraction at 24 h (P ≤ 0.05). In isolated hearts perfused for 120 min under constant pressure, LT did not significantly alter LV systolic or developed pressures at any time point, whereas ET decreased both of these at 24 h (P < 0.0001 initially). ET but not LT progressively increased plasma creatine phosphokinase and cardiac troponin levels (P < 0.05). In conclusion, despite echocardiographic changes, in vivo lethal LT challenge did not produce evidence of myocardial depression in isolated rat hearts. While lethal ET challenge did depress isolated heart function, this may have resulted from prior hypotension and ischemia.

P38 mitogen-activated protein kinase inhibitor SB203580 promotes peripheral blood lymphocyte apoptosis in rats with colitis

AIM: To investigate the influence of p38 mitogen-activated protein kinase inhibitor SB203580 on peripheral blood lymphocyte (PBL) apoptosis in rats with colitis and the possible mechanisms involved.

METHODS: Forty-five healthy female Sprague-Dawley (SD) rats were randomly divided into three groups: a normal group, a model group and a SB203580 group. Colitis was induced with 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) in rats of the latter two groups. The normal group and the model group were treated intrarectally with saline, while the SB203580 group was given SB203580 [1 mg/(kg•d)]. The rats were sacrificed after 2 wk to assess disease activity index (DAI) and macroscopic and histological changes of the colon. PBL apoptosis and Bcl-2 expression were examined by flow cytometry. p-ATF2 protein expression in colon tissue was determined by immunohistochemistry.

RESULTS: In the model group, the percentages of cells expressing p-ATF2 and Bcl-2 were higher than those in the normal group and SB203580 group (43.40% ± 2.67% vs 7.45% ± 1.26%, 20.70% ± 2.79%; 38.60% ± 3.53% vs 13.70% ± 2.45%, 20.30% ± 2.87%, P < 0.01 for all), but the percentage of apoptotic PBLs in the model group was lower than those in the normal group and SB203580 group (27.70% ± 3.02% vs 58.70% ± 3.09%, 46.60% ± 4.14%, P < 0.01 for both). DAI and macroscopic and histological scores in the model group were significantly higher than those in the normal group and SB203580 group (2.42 ± 0.30 vs 0.28 ± 0.29, 1.24 ± 0.17; 5.42 ± 0.30 vs 0.30 ± 0.48, 3.30 ± 0.22; 3.29 ± 0.26 vs 0.05 ± 0.20, 1.10 ± 0.74, P < 0.01 for all).

CONCLUSION: P38MAPK inhibitor SB203580 reduces colonic inflammatory injury in rats with colitis by down-regulating expression of p-ATF2 and Bcl-2 and inducing PBL apoptosis. SB203580 can be considered as a novel therapeutic alternative for the treatment of UC.

Induction of autophagy in hepatocellular carcinoma cells by SB203580 requires activation of AMPK and DAPK but not p38 MAPK

SB203580 is a well-known inhibitor of p38 mitogen-activated protein kinase (MAPK). However, it can suppress cell proliferation in a p38 MAPK independent manner. The inhibitory mechanism remains unknown. Here, we showed that SB203580 induced autophagy in human hepatocellular carcinoma (HCC) cells. SB203580 increased GFP-LC3-positive cells with GFP-LC3 dots, induced accumulation of autophagosomes, and elevated the levels of microtubule-associated protein light chain 3 and Beclin 1. It stimulated the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and p53, but inhibited the phosphorylation of death-associated protein kinase (DAPK). Inhibition of AMPK, p53, or DAPK attenuated SB203580-induced autophagy. AMPK activation appeared to predate the DAPK signal. The activation of both AMPK and DAPK prompted the phosphorylation of p53 and enhanced Beclin 1 expression. Neither the downregulation of p38 MAPK by its siRNA or chemical inhibitor nor the upregulation of p38 MAPK by p38 MAPK DNA transfection affected B203580-induced autophagy. Collectively, the findings demonstrate a novel function of SB203580 to induce autophagy via activating AMPK and DAPK but independent of p38 MAPK. The induction of autophagy can thus account for the antiproliferative effect of SB203580 in HCC cells.

Myocardial depressant effects of interleukin 6 in meningococcal sepsis are regulated by p38 mitogen-activated protein kinase

OBJECTIVES

Myocardial failure, leading to inotrope-unresponsive shock, is the predominant cause of death in meningococcal and other forms of septic shock. Proinflammatory cytokines released in septic shock are known to have myocardial depressant effects. We previously showed that interleukin 6 is a major myocardial depressant factor in children with meningococcal septicemia. In the current study, we aimed to investigate the mechanisms by which interleukin 6 induces myocardial failure in meningococcal sepsis and to identify potential novel therapeutic targets.

DESIGN

Laboratory-based study.

SETTING

University hospital and laboratories.

PATIENTS

Children with a clinical diagnosis of meningococcal septic shock.

METHODS

We studied interleukin 6-induced signaling events, both in vitro using isolated rat ventricular cardiac myocytes as a model of myocardial contractility and in whole blood from children with meningococcal sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We demonstrated involvement of Janus kinase 2, phosphatidylinositol 3-kinase, Akt, and p38 mitogen-activated protein kinase in interleukin 6-induced negative inotropy in isolated cardiac myocytes. Inhibition of p38 mitogen-activated protein kinase not only reversed interleukin 6-induced myocardial depression in both rat and human myocytes, but restored inotrope responsiveness. Cardiomyocytes transduced with dominant-negative p38 mitogen-activated protein kinase showed no interleukin 6-induced myocardial depression. To investigate p38 mitogen-activated protein kinase in vivo, we profiled global RNA expression patterns in peripheral blood of children with meningococcal septicemia. Transcripts for genes mapping to the p38 mitogen-activated protein kinase pathway showed significantly altered levels of abundance with a high proportion of genes of this pathway affected.

CONCLUSIONS

Our findings demonstrate an integral role of the p38 mitogen-activated protein kinase pathway in interleukin 6-mediated cardiac contractile dysfunction and inotrope insensitivity. Dysregulation of the p38 mitogen-activated protein kinase pathway in meningococcal septicemia suggests that this pathway may be an important target for novel therapies to reverse myocardial dysfunction in patients with meningococcal septic shock who are not responsive to inotropic support.

The effect of heparin administration in animal models of sepsis: a prospective study in Escherichia coli-challenged mice and a systematic review and metaregression analysis of published studies

INTRODUCTION

If thrombosis contributes to sepsis, heparin titrated using activated partial thromboplastin times may be efficacious. We investigated heparin in preclinical models.

METHODS AND MAIN RESULTS

In unchallenged mice (n = 107), heparin at 100, 500, or 2500 units/kg produced activated partial thromboplastin time levels less than, within, or greater than a prespecified therapeutic range (1.5-2.5 times control), respectively. In animals (n = 142) administered intratracheal Escherichia coli challenge, compared to placebo treatment, heparin at 100, 500, or 2500 units/kg were associated with dose dependent increases in the hazard ratios of death (hazard ratio [95% confidence interval]: 1.08 [0.66, 1.76]; 1.34 [0.80, 2.24]; 3.02 [1.49, 6.10], respectively) (p = .001 for the dose effect). Compared to normal saline challenge, E. coli without heparin (i.e., with placebo) increased the activated partial thromboplastin time (p = .002) close to the therapeutic range. While heparin at 100 and 500 units/kg with E. coli further increased activated partial thromboplastin time (p < .0001 vs. placebo) within or above the therapeutic range, respectively, these did not decrease inflammatory cytokines or lung injury. In metaregression analysis of published preclinical studies, heparin improved survival with lipopolysaccharide (n = 23, p < .0001) or surgically induced infection (n = 14, p < .0001) but not monobacterial (n = 7, p = .29) challenges.

CONCLUSION

Coagulopathy with sepsis or other variables, such as type of infectious source, may influence the efficacy of heparin therapy for sepsis.