Sesquiterpene lactone parthenolide, an inhibitor of IkappaB kinase complex and nuclear factor-kappaB, exerts beneficial effects in myocardial reperfusion injury

7-Hydroxy Frullanolide Ameliorates Isoproterenol-Induced Myocardial Injury through Modification of iNOS and Nrf2 Genes

Myocardial infarction (MI) is the principal cause of premature death. Protecting myocardium from ischemia is the main focus of intense research. 7-hydroxy frullanolide (7-HF) is a potent anti-inflammatory agent, showing its efficacy in different acute and chronic inflammatory disorders such as atherosclerosis, suggesting it can be a potential cardioprotective agent. For the induction of MI, Sprague-Dawley rats (n = 5) were administered isoproterenol (ISO) 85 mg/kg s.c at 24 h intervals for two days. The potential cardioprotective effect of 7-HF and its mechanisms were explored by in vivo and in vitro methods. 7-HF significantly prevented the extent of myocardial injury by decreasing the infarct size, preserving the histology of myocardial tissue, and reducing the release of cardiac biomarkers. Further, 7-HF increased the mRNA expression of cardioprotective gene Nrf2 and reduced the mRNA expression of iNOS. 7-HF also improved cardiac function by decreasing the cardiac workload through its negative chronotropic and negative ionotropic effect, as well as by reducing peripheral vascular resistance due to the inhibition of voltage-dependent calcium channels and the release of calcium from intracellular calcium stores. In conclusion, 7-HF showed cardioprotective effects in the MI model, which might be due to modulating the expression of iNOS and Nrf2 genes as well as improving cardiac functions.

Parthenolide Phytosomes Attenuated Gentamicin-Induced Nephrotoxicity in Rats via Activation of Sirt-1, Nrf2, OH-1, and NQO1 Axis

Nephrotoxicity is a serious complication that limits the clinical use of gentamicin (GEN). Parthenolide (PTL) is a sesquiterpene lactone derived from feverfew with various therapeutic benefits. However, PTL possesses low oral bioavailability. This study aimed to evaluate the therapeutic protective effects of PTL-phytosomes against GEN-induced nephrotoxicity in rats. The PTL was prepared as phytosomes to improve the pharmacological properties with a particle size of 407.4 nm, and surface morphology showed oval particles with multiple edges. Rats were divided into six groups: control, nano-formulation plain vehicle, PTL-phytosomes (10 mg/kg), GEN (100 mg/kg), GEN + PTL-phytosomes (5 mg/kg), and GEN + PTL-phytosomes (10 mg/kg). The administration of PTL-phytosomes alleviated GEN-induced impairment in kidney functions and histopathological damage, and decreased kidney injury molecule-1 (KIM-1). The anti-oxidative effect of PTL-phytosomes was demonstrated by the reduced malondialdehyde (MDA) concentration and increased superoxide dismutase (SOD) and catalase (CAT) activities. Furthermore, PTL-phytosomes treatment significantly enhanced sirtuin 1 (Sirt-1), nuclear factor erythroid-2-related factor-2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), and heme oxygenase-1 (HO-1). Additionally, PTL-phytosomes treatment exhibited anti-inflammatory and anti-apoptotic properties in the kidney tissue. These findings suggest that PTL-phytosomes attenuate renal dysfunction and structural damage by reducing oxidative stress, inflammation, and apoptosis in the kidney.

The microtubule cytoskeleton in cardiac mechanics and heart failure

The microtubule network of cardiac muscle cells has unique architectural and biophysical features to accommodate the demands of the working heart. Advances in live-cell imaging and in deciphering the 'tubulin code' have shone new light on this cytoskeletal network and its role in heart failure. Microtubule-based transport orchestrates the growth and maintenance of the contractile apparatus through spatiotemporal control of translation, while also organizing the specialized membrane systems required for excitation-contraction coupling. To withstand the high mechanical loads of the working heart, microtubules are post-translationally modified and physically reinforced. In response to stress to the myocardium, the microtubule network remodels, typically through densification, post-translational modification and stabilization. Under these conditions, physically reinforced microtubules resist the motion of the cardiomyocyte and increase myocardial stiffness. Accordingly, modified microtubules have emerged as a therapeutic target for reducing stiffness in heart failure. In this Review, we discuss the latest evidence on the contribution of microtubules to cardiac mechanics, the drivers of microtubule network remodelling in cardiac pathologies and the therapeutic potential of targeting cardiac microtubules in acquired heart diseases.

Gluconolactone Alleviates Myocardial Ischemia/Reperfusion Injury and Arrhythmias via Activating PKCε/Extracellular Signal-Regulated Kinase Signaling

Gluconolactone (D-glucono-1,5-lactone or GDL) is a food additive which presents in dietary products such as tofu, yogurt, cheese, bread, wine, etc. GDL has long been considered as a free radical scavenger; however, its role in cardioprotection remains elusive. In this study, using a mouse model of myocardial ischemia/reperfusion (I/R) injury and a model of hypoxia/reoxygenation (H/R) in neonatal rat cardiomyocytes (NRCM), we explored the role of GDL in I/R injury. We found that GDL (5 mg/kg, i.p.) attenuated myocardial I/R injury as evidenced by decreased infarct size, release of cardiac injury markers and apoptosis. Additionally, GDL decreased reperfusion-induced arrhythmias and oxidative stress. These effects were also observed in parallel in vitro studies. Mechanistically, we found that GDL treatment was strongly associated with activation of pro-survival extracellular signal-regulated kinase (ERK) signaling both in vivo and in vitro, and pharmacological inhibition of ERK signaling via U0126 attenuated GDL-induced cardioprotection against H/R injury in NRCM cells. To reveal how GDL regulates ERK signaling, we predicted the putative targets of GDL by Swiss Target Prediction, and protein kinase C (PKC) emerged as the most promising target for GDL. By pharmacological intervention and immunofluorescence, we found that PKCε, an important member of the PKC family, was activated after GDL treatment in heart, thereby leading to ERK activation and cardioprotection against I/R injury. Taken together, our results demonstrated that GDL acts as a potent activator of PKCε and, thus, provides cardioprotection against I/R injury via activation of ERK signaling.

Blocking the IL-1 receptor reduces cardiac transplant ischemia and reperfusion injury and mitigates CMV-accelerated chronic rejection

Ischemia-reperfusion injury (IRI) is an important risk factor for accelerated cardiac allograft rejection and graft dysfunction . Utilizing a rat heart isogeneic transplant model, we identified inflammatory pathways involved in IRI in order to identify therapeutic targets involved in disease. Pathway analyses identified several relevant targets, including cytokine signaling by the IL-1 receptor (IL-1R) pathway and inflammasome activation. To investigate the role of IL-1R signaling pathways during IRI, we treated syngeneic cardiac transplant recipients at 1-hour posttransplant with Anakinra, a US Food and Drug Administration (FDA)-approved IL-1R antagonist; or parthenolide, a caspase-1 and nuclear factor kappa-light-chain-enhancer of activated B cells inhibitor that blocks IL-1β maturation. Both Anakinra and parthenolide significantly reduced graft inflammation and cellular recruitment in the treated recipients relative to nontreated controls. Anakinra treatment administered at 1-hour posttransplant to recipients of cardiac allografts from CMV-infected donors significantly increased the time to rejection and reduced viral loads at rejection. Our results indicate that reducing IRI by blocking IL-1Rsignaling pathways with Anakinra or inflammasome activity with parthenolide provides a promising approach for extending survival of cardiac allografts from CMV-infected donors.

Damage-Associated Molecular Patterns in Myocardial Infarction and Heart Transplantation: The Road to Translational Success

In the setting of myocardial infarction (MI), ischemia reperfusion injury (IRI) occurs due to occlusion (ischemia) and subsequent re-establishment of blood flow (reperfusion) of a coronary artery. A similar phenomenon is observed in heart transplantation (HTx) when, after cold storage, the donor heart is connected to the recipient's circulation. Although reperfusion is essential for the survival of cardiomyocytes, it paradoxically leads to additional myocardial damage in experimental MI and HTx models. Damage (or danger)-associated molecular patterns (DAMPs) are endogenous molecules released after cellular damage or stress such as myocardial IRI. DAMPs activate pattern recognition receptors (PRRs), and set in motion a complex signaling cascade resulting in the release of cytokines and a profound inflammatory reaction. This inflammatory response is thought to function as a double-edged sword. Although it enables removal of cell debris and promotes wound healing, DAMP mediated signalling can also exacerbate the inflammatory state in a disproportional matter, thereby leading to additional tissue damage. Upon MI, this leads to expansion of the infarcted area and deterioration of cardiac function in preclinical models. Eventually this culminates in adverse myocardial remodeling; a process that leads to increased myocardial fibrosis, gradual further loss of cardiomyocytes, left ventricular dilation and heart failure. Upon HTx, DAMPs aggravate ischemic damage, which results in more pronounced reperfusion injury that impacts cardiac function and increases the occurrence of primary graft dysfunction and graft rejection via cytokine release, cardiac edema, enhanced myocardial/endothelial damage and allograft fibrosis. Therapies targeting DAMPs or PRRs have predominantly been investigated in experimental models and are potentially cardioprotective. To date, however, none of these interventions have reached the clinical arena. In this review we summarize the current evidence of involvement of DAMPs and PRRs in the inflammatory response after MI and HTx. Furthermore, we will discuss various current therapeutic approaches targeting this complex interplay and provide possible reasons why clinical translation still fails.

Applications of Sesquiterpene Lactones: A Review of Some Potential Success Cases

Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.

CaMKIIδ subtypes differentially regulate infarct formation following ex vivo myocardial ischemia/reperfusion through NF-κB and TNF-α

Deletion of Ca2+/calmodulin-dependent protein kinase II delta (CaMKIIδ) has been shown to protect against in vivo ischemia/reperfusion (I/R) injury. It remains unclear which CaMKIIδ isoforms and downstream mechanisms are responsible for the salutary effects of CaMKIIδ gene deletion. In this study we sought to compare the roles of the CaMKIIδB and CaMKIIδC subtypes and the mechanisms by which they contribute to ex vivo I/R damage. WT, CaMKIIδKO, and mice expressing only CaMKIIδB or δC were subjected to ex vivo global ischemia for 25min followed by reperfusion. Infarct formation was assessed at 60min reperfusion by triphenyl tetrazolium chloride (TTC) staining. Deletion of CaMKIIδ conferred significant protection from ex vivo I/R. Re-expression of CaMKIIδC in the CaMKIIδKO background reversed this effect and exacerbated myocardial damage and dysfunction following I/R, while re-expression of CaMKIIδB was protective. Selective activation of CaMKIIδC in response to I/R was evident in a subcellular fraction enriched for cytosolic/membrane proteins. Further studies demonstrated differential regulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling and tumor necrosis factor alpha (TNF-α) expression by CaMKIIδB and CaMKIIδC. Selective activation of CaMKIIδC was also observed and associated with NF-κB activation in neonatal rat ventricular myocytes (NRVMs) subjected to oxidative stress. Pharmacological inhibition of NF-κB or TNF-α significantly ameliorated infarct formation in WT mice and those that re-express CaMKIIδC, demonstrating distinct roles for CaMKIIδ subtypes in I/R and implicating acute activation of CaMKIIδC and NF-κB in the pathogenesis of reperfusion injury.

MicroRNA-223-5p and -3p Cooperatively Suppress Necroptosis in Ischemic/Reperfused Hearts

Recent studies have shown that myocardial ischemia/reperfusion (I/R)-induced necrosis can be controlled by multiple genes. In this study, we observed that both strands (5p and 3p) of miR-223 were remarkably dysregulated in mouse hearts upon I/R. Precursor miR-223 (pre-miR-223) transgenic mouse hearts exhibited better recovery of contractile performance over reperfusion period and lesser degree of myocardial necrosis than wild type hearts upon ex vivo and in vivo myocardial ischemia. Conversely, pre-miR-223 knock-out (KO) mouse hearts displayed opposite effects. Furthermore, we found that the RIP1/RIP3/MLKL necroptotic pathway and inflammatory response were suppressed in transgenic hearts, whereas they were activated in pre-miR-223 KO hearts upon I/R compared with wild type controls. Accordingly, treatment of pre-miR-223 KO mice with necrostatin-1s, a potent necroptosis inhibitor, significantly decreased I/R-triggered cardiac necroptosis, infarction size, and dysfunction. Mechanistically, we identified two critical cell death receptors, TNFR1 and DR6, as direct targets of miR-223-5p, whereas miR-223-3p directly suppressed the expression of NLRP3 and IκB kinase α, two important mediators known to be involved in I/R-induced inflammation and cell necroptosis. Our findings indicate that miR-223-5p/-3p duplex works together and cooperatively inhibits I/R-induced cardiac necroptosis at multiple layers. Thus, pre-miR-223 may constitute a new therapeutic agent for the treatment of ischemic heart disease.

Parthenolide-Induced Cytotoxicity in H9c2 Cardiomyoblasts Involves Oxidative Stress

BACKGROUND

Cardiac cellular injury as a consequence of ischemia and reperfusion involves nuclear factor-κB (NF-κ B), amongst other factors, and NF-κ B inhibitors could substantially reduce myocardial infarct size. Parthenolide, a sesquiterpene lactone compound which could inhibit NF-κ B, has been shown to ameliorate myocardial reperfusion injury but may also produce toxic effects in cardiomyocytes at high concentrations. The aim of this study was to examine the cytotoxic effects of this drug on H9c2 cardiomyoblasts, which are precursor cells of cardiomyocytes.

METHODS

Cell viability and apoptosis were examined by MTT and TUNEL assay, respectively, and protein expression was analyzed by western blot. Reactive oxygen species (ROS) production was measured using DCFH-DA as dye. Cytosolic Ca(2+) concentration and mitochondrial membrane potential were measured microfluorimetrically using, respectively, fura 2 and rhodamine 123 as dyes.

RESULTS

Parthenolide caused apoptosis at 30 μ M, as judged by TUNEL assay and Bax and cytochrome c translocation. It also caused collapse of mitochondrial membrane potential and endoplasmic reticulum stress. Parthenolide triggered ROS formation, and vitamin C (antioxidant) partially alleviated parthenolide-induced cell death.

CONCLUSIONS

The results suggested that parthenolide at high concentrations caused cytotoxicity in cardiomyoblasts in part by inducing oxidative stress, and demonstrated the imperative for cautious and appropriate use of this agent in cardioprotection.

KEY WORDS

Cardiomyoblast; Endoplasmic reticulum stress; Oxidative stress; Parthenolide; Reperfusion injury.

Insulin/NFκB protects against ischemia-induced necrotic cardiomyocyte death

In the heart, insulin controls key functions such as metabolism, muscle contraction and cell death. However, all studies have been focused on insulin action during reperfusion. Here we explore the cardioprotective action of this hormone during ischemia. Rat hearts were perfused ex vivo with an ischemia/reperfusion Langendorff model in absence or presence of insulin. Additionally, cultured rat cardiomyocytes were exposed to simulated ischemia in the absence or presence of insulin. Cytoprotective effects were measured by myocardial infarct size, trypan blue exclusion, released LDH and DNA fragmentation by flow cytometry. We found that insulin protected against cardiac ischemia ex vivo and in vitro. Moreover, insulin protected cardiomyocytes from simulated ischemia by reducing necrotic cell death. Protective effects of insulin were dependent of Akt and NFκB. These novel results show that insulin reduces ischemia-induced cardiomyocyte necrosis through an Akt/NF-κB dependent mechanism. These novel findings clarify the role of insulin during ischemia and further support its use in early GIK perfusion to treat myocardial infarction.

Parthenolide inhibits polyethylene particle-induced mouse calvarial osteolysis in vivo

BACKGROUND

Periprosthetic osteolysis and aseptic loosening (AL) after joint arthroplasty are serious problems encountered after an implant surgery. AL is possibly caused by osteolysis or local bone resorption induced by implant-derived wear particles. However, effective treatments for osteoclastic bone resorption and AL mediated by wear particles have not been developed except surgical revision. Therefore, a new strategy should be developed to improve osteolysis associated with AL via pharmacologic intervention.

MATERIALS AND METHODS

The effects of parthenolide (PTN), a nuclear factor-kappa B inhibitor and sesquiterpene lactone, on polyethylene particle-induced osteolysis in vivo were investigated using a mouse calvarial model. Bone volume/tissue volume (BV/TV, %), bone surface/bone volume (BS/BV, 1/mm), osteoclast number per bone perimeter (N.Oc/B.Pm, /mm), and eroded surface per bone surface (ES/BS, %) were determined by micro-computed tomography and histologic analyses.

RESULTS

Severe bone resorption and rapid osteoclast formation were found in the cranium of the subjects after polyethylene particles were implanted. ES/BS (P < 0.001), N.Oc/B.Pm (group III, P < 0.05; group IV, P < 0.001), and BS/BV (P < 0.001) increased compared with those in group II; BS/BV (P < 0.001) decreased in group II but was improved in groups III and IV, which were treated with PTN. No significant difference in these parameters was observed among groups I, III, and IV.

CONCLUSIONS

PTN possibly elicited therapeutic effects on osteolysis induced by wear particles, indicating that PTN could be used as a therapeutic agent of AL induced by wear particles.

Effects of Thyroid Hormone Analogue and a Leukotrienes Pathway-Blocker on Reperfusion Injury Attenuation after Heart Transplantation

Background. Global myocardial ischemia reperfusion injury after heart transplantation is believed to impair graft function and aggravate both acute and chronic rejection episodes. Objectives. To assess the possible protective potential of MK-886 and 3,5-diiodothyropropionic acid DITPA against global myocardial ischemia reperfusion injury after heart transplantation. Materials and Methods. Adult albino rats were randomized into 6 groups as follows: group I sham group; group II, control group; groups III and IV, control vehicles (1,2); group V, MK-886 treated group. Donor rats received MK-886 30 min before transplantation, and the same dose was repeated for recipients upon reperfusion; in group VI, DITPA treated group, donors and recipients rats were pretreated with DITPA for 7 days before transplantation. Results. Both MK-886 and DITPA significantly counteract the increase in the levels of cardiac TNF-α, IL-1β, and ICAM-1 and plasma level of cTnI (P < 0.05). Morphologic analysis showed that both MK-886 and DITPA markedly improved (P < 0.05) the severity of cardiac injury in the heterotopically transplanted rats. Conclusions. The results of our study reveal that both MK-886 and DITPA may ameliorate global myocardial ischemia reperfusion injury after heart transplantation via interfering with inflammatory pathway.

Parthenolide is neuroprotective in rat experimental stroke model: downregulating NF-κB, phospho-p38MAPK, and caspase-1 and ameliorating BBB permeability

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Parthenolide (PN) has been proved to elicit a wide range of biological activities through its anti-inflammatory action in the treatment of migraine, arthritis, and atherosclerosis. To decide whether this effect applies to ischemic injury in brain, we therefore investigate the potential neuroprotective role of PN and the underlying mechanisms. Male Sprague-Dawley rats were randomly divided into Saline, Vehicle, and PN groups and a permanent middle cerebral artery occlusion (MCAO) model was used. PN administered intraperitoneally immediately after cerebral ischemia and once daily on the following days. At time points after MCAO, neurological deficit, infarct volume, and brain water content were measured. Immunohistochemistry, western blot and RT-PCR were used to analyze the expression of NF- κ B and caspase-1 in ischemic brain tissue. Phospho-p38MAPK and claudin-5 were detected by western blot. The results indicated that PN dramatically ameliorated neurological deficit, brain water content, and infarct volume, downregulated NF- κ B, phospho-p38MAPK, and caspase-1 expressions, and upregulated claudin-5 expression in ischemic brain tissue.

CONCLUSIONS

PN protected the brain from damage caused by MCAO; this effect may be through downregulating NF- κ B, phosho-p38MAPK, and caspase-1 expressions and ameliorating BBB permeability.

Pd-catalyzed diastereoselective allylation of aldehydes with 3-bromomethyl-5H-furan-2-one: stereoselective synthesis of β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones with a syn configuration

An efficient and diastereoselective Pd-catalyzed method of allylation of aldehydes with 3-bromomethyl-5H-furan-2-one is described. The proposed method allows the synthesis of β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones with a syn relative configuration for the first time.

Parthenolide attenuates LPS-induced activation of NF-κB in a time-dependent manner in rat myocardium

Parthenolide (PTN), a selective nuclear factor kappa B (NF-κB) inhibitor, has been used extensively to inhibit NF-κB activation. The duration of the inhibitory effect of PTN on NF-κB in vivo remains unclear. This study was to determine whether a lipopolysaccharide (LPS) challenge 6, 12 and 24 h after the administration of PTN could activate NF-κB. Rats were devided into five groups. The rats in the PTN, PTN+LPS and DMSO groups were injected intraperitoneally with PTN or DMSO. After 6, 12 or 24 h, LPS was administered in LPS and PTN+LPS groups. The expressions of NF-κB p50, IκBα and p-IκBα were inhibited in both PTN and PTN+LPS group at end of 6 and 12 h and no effects at 24 h. In summary, myocardial NF-κB expression occurs 1 h after the administration of LPS. PTN blocks this effect given at 6 h and no inhibitory effect 24 h after administration in vivo.

Delayed anesthetic preconditioning protects against myocardial infarction via activation of nuclear factor-κB and upregulation of autophagy

PURPOSE

Delayed volatile anesthetic preconditioning (APC) can protect against myocardial ischemia/reperfusion (I/R) injury; the delayed phase is called the second window of protection (SWOP), but the underlying mechanism is unclear. Nuclear factor-κB (NF-κB) is involved in the myocardial protection conferred by APC in the acute phase; autophagy has been reported to confer apoptosis inhibition and infarction reduction. We hypothesized that APC initiates delayed cardioprotection against I/R injury via the activation of NF-kB and upregulation of autophagy, thus attenuating the inflammatory response and apoptosis

METHODS

After a rat I/R model was set up, left ventricular samples were obtained before I/R to assess NF-κB-DNA binding activity and microtubule-associated protein 1 light chain 3 (LC3) and cathepsin B protein expression, and to examine autophagosomes with a transmission electron microscope. Infarct size and the expressions of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and caspase-3 were measured at the end of 2-h reperfusion.

RESULTS

The infarct size was significantly reduced in the SWOP group (30 ± 3 %) when compared with that in the I/R group (47 ± 7 %, P < 0.05), and this finding was associated with increased NF-κB-DNA binding activity and autophagosomes. In addition, the expressions of LC3-II and cathepsin B were also up-regulated, and the expressions of TNF-α, IL-1β, and caspase-3 were attenuated in the SWOP group when compared with the findings in the I/R group. However, this protection was abolished by the administration of parthenolide (PTN) before sevoflurane inhalation, which resulted in an infarct size that was significantly increased (47 ± 5 %, P < 0.05 PTN + SWOP vs. SWOP group).

CONCLUSION

Delayed APC protected the rat heart from I/R injury. The underlying mechanisms may include NF-κB activation, upregulation of autophagy, and the attenuation of TNF-α, IL-1β, and caspase-3 expressions.

Parthenolide, an inhibitor of the nuclear factor-κB pathway, ameliorates dextran sulfate sodium-induced colitis in mice

BACKGROUND

Activation of nuclear factor-kappa B (NF-κB), which controls transcription of various pro-inflammatory cytokine genes, has been shown to play a critical role in the pathogenesis of ulcerative colitis (UC). Parthenolide, a sesquiterpene lactone compound isolated from extracts of the herb Feverfew (Tanacetum parthenium), has been demonstrated to be a potent inhibitor of NF-κB activation. This study was designed to investigate the effects of parthenolide on an experimental murine colitis model.

MATERIALS AND METHODS

Experimental colitis was induced by dextran sulfate sodium (DSS), and mice were divided into 3 groups: normal control, DSS+saline, and DSS+parthenolide. The disease activity index (DAI) and histological score were observed. The tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels were measured by enzyme-linked immunosorbent assay. Phospho-IκBα, IκBα and phospho-NF-κB p65 expression were assessed by western blot analysis. Myeloperoxidase (MPO) activity was determined by using MPO assay kit.

RESULTS

Administration of parthenolide significantly reduced the severity of DSS-induced colitis as assessed by DAI and histological score, and resulted in downregulation of MPO activity and phospho-NF-κB p65 expression by the blockade of phosphorylation and subsequent degradation of IκB protein, strikingly reduced the production of TNF-α and IL-1β.

CONCLUSION

Parthenolide exerts beneficial effects in experimental colitis and may therefore provide a useful therapeutic approach for the treatment of UC.

Xanthane sesquiterpenoids: structure, synthesis and biological activity

The aim of this review is to survey the naturally occurring xanthanes and xanthanolides, their structures, biological activities, structure–activity relationships and synthesis. There has been no comprehensive review of this topic previously. On the basis of 126 references, 112 compounds are summarized.

Role of nuclear factor kappaB in cardiovascular health and disease

Cardiovascular pathologies are still the primary cause of death worldwide. The molecular mechanisms behind these pathologies have not been fully elucidated. Unravelling them will bring us closer to therapeutic strategies to prevent or treat cardiovascular disease. One of the major transcription factors that has been linked to both cardiovascular health and disease is NF-kappaB (nuclear factor kappaB). The NF-kappaB family controls multiple processes, including immunity, inflammation, cell survival, differentiation and proliferation, and regulates cellular responses to stress, hypoxia, stretch and ischaemia. It is therefore not surprising that NF-kappaB has been shown to influence numerous cardiovascular diseases including atherosclerosis, myocardial ischaemia/reperfusion injury, ischaemic preconditioning, vein graft disease, cardiac hypertrophy and heart failure. The function of NF-kappaB is largely dictated by the genes that it targets for transcription and varies according to stimulus and cell type. Thus NF-kappaB has divergent functions and can protect cardiovascular tissues from injury or contribute to pathogenesis depending on the cellular and physiological context. The present review will focus on recent studies on the function of NF-kappaB in the cardiovascular system.

Parthenolide inhibits proliferation of vascular smooth muscle cells through induction of G0/G1 phase cell cycle arrest

OBJECTIVE

This study is to determine the effect of the natural product parthenolide, a sesquiterpene lactone isolated from extracts of the herb Tanacetum parthenium, on the proliferation of vascular smooth muscle cells (VSMCs).

METHODS

Rat aortic VSMCs were isolated and cultured in vitro, and treated with different concentrations of parthenolide (10, 20 and 30 mumol/L). [(3)H]thymidine incorporation was used as an index of cell proliferation. Cell cycle progression and distribution were determined by flow cytometric analysis. Furthermore, the expression of several regulatory proteins relevant to VSMC proliferation including IkappaBalpha, cyclooxygenase-2 (Cox-2), p21, and p27 was examined to investigate the potential molecular mechanism.

RESULTS

Treatment with parthenolide significantly decreased the [(3)H]thymidine incorporation into DNA by 30%~56% relative to control values in a dose-dependent manner (P<0.05). Addition of parthenolide also increased cell population at G(0)/G(1) phase by 19.2%~65.7% (P<0.05) and decreased cell population at S phase by 50.7%~84.8% (P<0.05), which is consistent with its stimulatory effects on p21 and p27. In addition, parthenolide also increased IkappaBalpha expression and reduced Cox-2 expression in a time-dependent manner.

CONCLUSION

Our results show that parthenolide significantly inhibits the VSMC proliferation by inducing G(0)/G(1) cell cycle arrest. IkappaBalpha and Cox-2 are likely involved in such inhibitory effect of parthenolide on VSMC proliferation. These findings warrant further investigation on potential therapeutic implications of parthenolide on VSMC proliferation in vivo.

Cardioprotective effect of pretreatment with β-glucan in coronary artery bypass grafting

BACKGROUND

Beta-glucan pretreatment has been shown to attenuate inflammatory response and to protect against ischemia-reperfusion injury in animal studies. The aims of the present study were to examine the safety of pretreatment with beta-1,3/1,6-glucan in patients scheduled for coronary artery bypass grafting (CABG), and to investigate whether beta-1,3/1,6-glucan pretreatment could suppress inflammatory response and protect against ischemia-reperfusion injury following CABG.

METHODS

Twenty one patients scheduled for CABG were assigned to oral beta-1,3/1,6-glucan 700 mg (Group 1) or 1 400 mg (Group 2) five consecutive days before surgery and were compared with a control group (Group 3). Blood samples were drawn preoperatively and on the first, third and fifth postoperative day for analysis of acute-phase reactants, hematology, cytokines and myocardial enzymes.

RESULTS

The study drug was well tolerated. Creatine kinase isoenzyme MB was significantly lower in Group 2 compared with controls on the first postoperative day (p = 0.028). Mean change in cardiac troponin T was lower in Group 2 compared with controls (p = 0.028).

CONCLUSIONS

Beta-1,3/1,6-glucan pretreatment is safe in patients undergoing CABG and may protect against ischemia reperfusion injury following CABG.

Molecular Biology of Apoptosis in Ischemia and Reperfusion

This study reviews the current understanding of the mechanisms that mediate the complex processes involved in apoptosis secondary to ischemia and reperfusion (I/R) and is not intended as a complete literature review of apoptosis. Several biochemical reactions trigger a cascade of events, which activate caspases. These caspases exert their effect through downstream proteolysis until the final effector caspases mediate the nuclear features characteristic of apoptosis, DNA fragmentation and condensation. Within the context of ischemia, the hypoxic environment initiates the expression of several genes involved in inflammation, the immune response, and apoptosis. Many of these same genes are activated during reperfusion injury in response to radical oxygen species generation. It is plausible that inhibition of specific apoptotic pathways via inactivation or downregulation of those genes responsible for the initiation of inflammation, immune response, and apoptosis may provide promising molecular targets for ameliorating reperfusion injury in I/R-related processes. Such inhibitory mechanisms are discussed in this review. Important targets in I/R-related pathologies include the brain during stroke, the heart during myocardial infarction, and the organs during harvesting and/or storage for transplantation. In addition, we present data from our ongoing research of specific signal transduction-related elements and their role in ischemia/reperfusion injury. These data address the potential therapeutic application of anti-inflammatory and anti-ischemic compounds in the prevention of I/R damage.

Induction of endotoxin tolerance enhances bacterial clearance and survival in murine polymicrobial sepsis

The fundamental mechanisms that underlie endotoxin tolerance remain to be elucidated, and the clinical significance of endotoxin tolerance in the context of active systemic infection remains in question. We hypothesized that the endotoxin tolerance phenotype would result in decreased inflammation at the expense of altered bacterial clearance and, thus, higher mortality in a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). Endotoxin tolerance was induced in C57Bl/6 mice with 5 mg/kg LPS or vehicle 18 h before subsequent CLP. Lung tissue, peritoneal fluid, and blood were collected at 1, 3, 6, and 18 h after surgery for subsequent analysis. Peritoneal macrophages were isolated for ex vivo phagocytosis assay. In separate experiments, mice were allowed to recover, and survival was monitored for 7 days. Endotoxin tolerance attenuated plasma TNF-alpha and IL-6 at 6 h after CLP. Peritoneal fluid cytokines were significantly attenuated as well. Endotoxin tolerance significantly improved bacterial clearance in both blood and peritoneal fluid after CLP. Similarly, ex vivo phagocytosis by primary peritoneal macrophages and RAW264.7 murine peritoneal macrophages was significantly improved after induction of the endotoxin tolerance phenotype. Contrary to our original hypothesis, we conclude that endotoxin tolerance significantly attenuates the host inflammatory response, augments bacterial clearance, and improves survival in this murine model of polymicrobial sepsis.

Dimethyl fumarate, a small molecule drug for psoriasis, inhibits Nuclear Factor-kappaB and reduces myocardial infarct size in rats

Persistent Nuclear Factor-kappaB (NF-kappaB) activation is hypothesized to contribute to myocardial injuries following ischemia-reperfusion. Because inhibition or control of NF-kappaB signaling in the heart probably confers cardioprotection, we determined the potency of the NF-kappaB inhibitor dimethyl fumarate (DMF) in cardiovascular cells, and determined whether administration of DMF translates into beneficial effects in an animal model of myocardial infarction. In rat heart endothelial cells (RHEC), we analysed inhibitory effects of DMF on NF-kappaB using shift assay and immunohistofluorescence. In in vivo experiments, male Sprague Dawley rats undergoing left coronary artery occlusion for 45 min received either DMF (10 mg/kg body weight) or vehicle 90 min before ischemia as well as immediately before ischemia. After 120 min of reperfusion, the hearts were stained with phthalocyanine blue dye and triphenyltetrazolium chloride. Additionally, acute hemodynamic and electrophysiologic effects of DMF were determined in dose-response experiments in isolated perfused rat hearts. DMF inhibited TNF-alpha-induced nuclear entry of NF-kappaB in RHEC. In in vivo experiments, myocardial infarct size was significantly smaller in rats that had received DMF (20.7%+/-9.7% in % of risk area; n=17) than in control rats (28.2%+/-6.2%; n=15). Dose-response experiments in isolated perfused rat hearts excluded acute hemodynamic or electrophysiologic effects as mechanisms for the effects of DMF. DMF inhibits nuclear entry of NF-kappaB in RHEC and reduces myocardial infarct size after ischemia and reperfusion in rats in vivo. There was no indication that the beneficial effects of DMF were due to acute hemodynamic or electrophysiologic influences.

DIVERSE CARDIOPROTECTIVE SIGNALING MECHANISMS OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-γ LIGANDS, 15-DEOXY-Δ12,14-PROSTAGLANDIN J2 AND CIGLITAZONE, IN REPERFUSION INJURY

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a nuclear receptor that regulates diverse biological functions including inflammation. The PPARgamma ligands have been reported to exert cardioprotective effects and attenuate myocardial reperfusion injury. Here, we examined the molecular mechanisms of their anti-inflammatory effects. Male Wistar rats were subjected to myocardial ischemia and reperfusion and were treated with the PPAR-gamma ligands, 15-deoxy-Delta-prostaglandin J2 (15d-PGJ2) or ciglitazone, or with vehicle only, in the absence or presence of the selective PPAR-gamma antagonist GW-9662. In vehicle-treated rats, myocardial injury was associated with elevated tissue activity of myeloperoxidase, indicating infiltration of neutrophils, and elevated plasma levels of creatine kinase and tumor necrosis factor-alpha. These events were preceded by activation of the nuclear factor-kappaB pathway. The PPAR-gamma DNA binding was also increased in the heart after reperfusion. Treatment with ciglitazone or 15d-PGJ2 reduced myocardial damage and neutrophil infiltration and blunted creatine kinase levels and cytokine production. The beneficial effects of both ligands were associated with enhancement of PPAR-gamma DNA binding and reduction of nuclear factor-kappaB activation. Treatment with 15d-PGJ2, but not ciglitazone, enhanced DNA binding of heat shock factor 1 and upregulated the expression of the cardioprotective heat shock protein 70. Treatment with 15d-PGJ2, but not ciglitazone, also induced a significant increase in nuclear phosphorylation of the prosurvival kinase Akt. The cardioprotection afforded by ciglitazone was attenuated by the PPAR-gamma antagonist GW-9662. In contrast, GW-9662 did not affect the beneficial effects afforded by 15d-PGJ2. Thus, our data suggest that treatment with these chemically unrelated PPAR-gamma ligands results in diverse anti-inflammatory mechanisms.

Evidence that IL-6-type cytokine signaling in cardiomyocytes is inhibited by oxidative stress: parthenolide targets JAK1 activation by generating ROS

Parthenolide, an anti-inflammatory compound, was reported to inhibit signal transducer and activator of transcription 3 (STAT3) activation by the interleukin (IL)-6-type cytokines by an undefined process, which was the focus of our study. Here we report that parthenolide reduced both basal and leukemia inhibitory factor (LIF)-induced STAT3 tyrosine 705 (Y705) phosphorylation in cardiomyocytes in a dose-dependent manner, but stimulated the MAP kinase signaling pathways. Activation of Janus kinase 1 (JAK1) tyrosine kinase was markedly reduced by parthenolide. Pretreatment with parthenolide inhibited JAK1-mediated phosphorylation of the LIF receptor subunits LIF receptor (LIFR) alpha and glycoprotein 130 (gp130), and reduced the LIF-induced increase in JAK1 association with both components. In addition, we documented that parthenolide, over the same concentration range, does not have a direct inhibitory effect on JAK1 autophosphorylation. However, we observed that parthenolide increased intracellular reactive oxygen species (ROS). Pretreatment with the antioxidant, N-acetyl-L-cysteine, completely suppressed the effect of parthenolide on JAK1 and STAT3. From these results, we conclude ROS generation in cardiomyocytes blocks STAT3 signaling of the IL-6-type cytokines by targeting JAK1. The finding that signaling by the IL-6-type cytokine may be redox-sensitive defines a novel mechanism of regulation that has implications for exploiting their therapeutic potential.

Proteasome inhibition attenuates infarct size and preserves cardiac function in a murine model of myocardial ischemia-reperfusion injury

BACKGROUND

Despite improvements in protection, myocardial ischemia-reperfusion remains an important cause of cardiac dysfunction. Multiple strategies exist experimentally; few are clinically accessible. Nuclear factor kappa-B (NF-kappaB) is a transcription factor central to the inflammatory response and is implicated in reperfusion injury. Its activation relies on the degradation of its inhibitory molecule, IkappaB, by the 20S proteasome. We hypothesized that proteasome inhibition would decrease the extent of infarction after temporary coronary occlusion.

METHODS

C57Bl6 mice received a specific proteasome inhibitor (PS-519) and were subjected to 30 minutes of transient occlusion of the left anterior descending artery. After 24 hours of reperfusion, echocardiography was performed to evaluate ventricular function and hearts were excised and analyzed for infarct size, areas at risk, and molecular markers of injury and NF-kappaB activation.

RESULTS

Compared with controls, PS-519 delivered before left anterior descending (coronary artery) ligation reduced the area of infarct without a change in the area at risk. Similar results were seen with PS-519 delivered at reperfusion. Echocardiography demonstrated a relative reduction in fractional shortening in the vehicle group of 9.8% versus only 2.7% in the PS-519 group. Markers of myocardial stress and injury were accordingly suppressed with PS-519. These physiologic findings were associated with PS-519 decreasing p65 and TNF expression while preserving IkappaB alpha expression.

CONCLUSIONS

In this murine infarct model PS-519 significantly preserved regional myocardial function, reduced the size of infarction, and attenuated expression of myocardial inflammatory response genes. These data demonstrate that a currently available and well-tolerated inhibitor of NF-kappaB can decrease the risk of myocardial injury associated with ischemia-reperfusion.

Parthenolide inhibits IkappaB kinase, NF-kappaB activation, and inflammatory response in cystic fibrosis cells and mice

Cystic fibrosis (CF) is characterized by prolonged and excessive inflammatory responses in the lung and increased activation of NF-kappaB. Parthenolide is a sesquiterpene lactone derived from the plant feverfew, which has been used in folk medicine for anti-inflammatory activity. Several studies suggest that this compound inhibits the NF-kappaB pathway, but the exact site is controversial. We hypothesized that parthenolide might ameliorate the excessive inflammatory response in CF models by inhibiting activation of NF-kappaB. This was tested in vitro, using two pairs of cell lines with defective versus normal CF transmembrane conductance regulator (CFTR) (antisense/sense transfected 16 HBE and IB-3/S9), and in vivo, using CFTR-knockout (KO) mice. All cell lines were pretreated with parthenolide and then stimulated with IL-1beta and/or TNF. Parthenolide significantly inhibited IL-8 secretion induced by these cytokines and prevented NF-kappaB activation, IkappaBalpha degradation, and IkappaB Kinase complex activity. CFTR-KO and wild-type mice were pretreated with parthenolide or vehicle alone then challenged intratracheally with LPS. Bronchoalveolar lavage was performed 3, 6, and 8 h later. Parthenolide pretreatment inhibited PMN influx as well as cytokine and chemokine production. This was also associated with inhibition of IkappaBalpha degradation and NF-kappaB activation. We thus conclude that parthenolide inhibits IkappaB kinase, resulting in stabilization of cytoplasmic IkappaBalpha, which in turn leads to inhibition of NF-kappaB translocation and attenuation of subsequent inflammatory responses. IkappaB kinase may be a good target, and parthenolide and/or feverfew might be promising treatments for the excessive inflammation in CF.

Parthenolide modulates the NF-kappaB-mediated inflammatory responses in experimental atherosclerosis

OBJECTIVE

Activation of transcription factor NF-kappaB is an important step in the development of vascular damage, because it controls inducible genes, including many inflammatory mediators. The pharmacological modulation of this process is the main objective in the design of new therapies for atherosclerosis. In this work we analyzed the effects of the natural compound parthenolide (PTN), an NF-kappaB inhibitor.

METHODS AND RESULTS

In vascular smooth muscle cells (VSMCs) and monocytes stimulated with lipopolysaccharide (LPS), nontoxic doses of PTN reduced IkappaBalpha degradation, NF-kappaB activation, and MCP-1 expression, without inhibiting AP-1 and MAPK. In apoE mice, treatment with low (2 mg/kg, 20 weeks), medium (4 mg/kg, 10 weeks), and high (10 mg/kg, 10 weeks) dose of PTN reduced the size of aortic lesion, decreased macrophage, and increased VSMC content in the lesions. Treated mice showed reduced serum levels of MCP-1 and attenuated NF-kappaB activity, but not AP-1, in the lesions. Moreover, PTN affects neither apoptotic cell death nor oxidative stress in cultured cells and mice.

CONCLUSIONS

NF-kappaB inhibition by PTN retards atherosclerotic lesions in apoE mice, by reducing lesion size and changing plaque composition. This natural compound could represent a novel therapeutic approach to inflammation during vascular damage.

SUPEROXIDE POTENTIATES NF-??B ACTIVATION AND MODULATES ENDOTOXIN-INDUCED CYTOKINE PRODUCTION IN ALVEOLAR MACROPHAGES

Gram-negative bacterial infection predisposes to the development of shock and acute lung injury with multiple organ dysfunction in the critically ill. Although overexpression of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta, IL-6, IL-8, and other mediators is causally implicated in the pathogenesis of shock and lung injury, the underlying mechanisms following cellular exposure to gram-negative endotoxin remain unclear. De novo generation of reactive oxygen species (ROS) by monocytes/macrophages in particular has been proposed as a pivotal regulatory mechanism by which enhanced transactivation of redox-sensitive genes culminates in augmented cytokine expression within the lower respiratory tract. Here we sought to characterize the mechanism of action of a synthetic, nonpeptide, low-molecular-weight, Mn-containing superoxide dismutase mimetic (SODm), M40403, in modulating E. coli lipopolysaccharide serotype 0111:B4 (LPS)-induced cytokine production by cultured rat alveolar macrophages. Intracellular superoxide (O2) ion generation was measured using hydroethidine (HE) dye, and the dose-dependent effects of M40403 on TNF-alpha and IL-6 biosynthesis by ELISAs. Upstream redox-sensitive signaling events involving the pleiotropic transcription factor NF-kappaB were determined in nuclear extracts by electrophoretic mobility shift assays (EMSAs) and p65 subunit Western blot. The levels of the cytosolic inhibitory protein IkappaB-alpha were also assessed by Western analysis. We found that M40403 potently suppressed the production of superoxide, TNF-alpha, and IL-6 in LPS-stimulated alveolar macrophages, suggesting a key role for superoxide in endotoxin-induced cytokine production in the distal air spaces. In addition, M40403 decreased E. coli LPS-induced activation of NF-kappaB, and this effect was associated with modest suppression of cytoplasmic IkappaB-alpha degradation. Together, these results suggest that removal of superoxide by M40403 inhibits endotoxin-induced production of TNF-alpha and IL-6 in alveolar macrophages by a mechanism involving suppression of redox-sensitive NF-kappaB transactivation or signaling.

WY 14643, A POTENT EXOGENOUS PPAR-?? LIGAND, REDUCES INTESTINAL INJURY ASSOCIATED WITH SPLANCHNIC ARTERY OCCLUSION SHOCK

The peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid, and thyroid hormone receptors. WY 14643 is a potent PPAR-alpha ligand that modulates the transcription of target genes. The aim of this study was to investigate the effect of WY 14643 on the tissue injury caused by ischemia-reperfusion (I/R) of the gut. I/R injury of the intestine was caused by clamping both the superior mesenteric artery and the celiac trunk for 45 min, followed by release of the clamp, allowing reperfusion for 2 h or 4 h. This procedure results in splanchnic artery occlusion (SAO) shock. Rats subjected to SAO developed a significant fall in mean arterial blood pressure, and only 20% of the animals survived for the entire 4-h reperfusion period. Surviving animals were sacrificed for histological examination and biochemical studies. Rats subjected to SAO displayed a significant increase in tissue myeloperoxidase (MPO) activity, significant increases in plasma tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta levels, and marked injury to the distal ileum. Increased immunoreactivity to nitrotyrosine and polyadenosine diphosphate [ADP]-ribose (PAR) was observed in the ileum of rats subjected to SAO. Staining of sections of the ileum obtained from SAO rats with anti-intercellular adhesion molecule (ICAM-1) antibody or with anti-P-selectin antibody resulted in diffuse staining. Administration of WY 14643 (1 mg/kg i.v.) 30 min before the onset of gut ischemia significantly reduced the (a) fall in mean arterial blood pressure, (b) mortality rate, (c) infiltration of the reperfused intestine with polymorphonuclear neutrophils (MPO activity), (d) production of proinflammatory cytokines (TNF-alpha and IL-1beta), and (e) histological evidence of gut injury. Administration of WY 14643 also markedly reduced the nitrotyrosine formation, poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) activation, up-regulation of ICAM-1, and expression of P-selectin during reperfusion. These results demonstrate that the PPAR-alpha agonist WY 14643 significantly reduces I/R injury of the intestine.

Pyrrolidine dithiocarbamate reduces the severity of cerulein-induced murine acute pancreatitis

The nuclear factor-kappaB (NF-kappaB) is a transcription factor that plays a pivotal role in the induction of genes involved in the response to injury and inflammation. Dithiocarbamates are antioxidants that are potent inhibitors of NF-kappaB. This study tested the hypothesis that pyrrolidine dithiocarbamate (PDTC) attenuates experimental acute pancreatitis. Intraperitoneal injection of cerulein in mice resulted in severe, acute pancreatitis characterized by edema, neutrophil infiltration, tissue hemorrhage and necrosis, and elevated serum levels of amylase and lipase. Infiltration of pancreatic and lung tissue with neutrophils (measured as increase in myeloperoxidase activity) was associated with enhanced lipid peroxidation (increased tissue levels of malondialdehyde). Immunohistochemical examination demonstrated a marked increase in immunoreactivity for nitrotyrosine and intracellular adhesion molecule-1 in the pancreas and lung of cerulein-treated mice. In contrast, the degree of 1) pancreas and lung injury, 2) upregulation/expression of intracellular adhesion molecule-1, 3) staining for nitrotyrosine, and 4) lipid peroxidation was markedly reduced by pretreatment with PDTC. This study demonstrates that prevention of the activation of NF-kappaB by PDTC ameliorates the tissue injury associated with experimental murine acute pancreatitis and provides an important insight into the molecular biology of acute pancreatitis.

Parthenolide improves systemic hemodynamics and decreases tissue leukosequestration in rats with polymicrobial sepsis

OBJECTIVE

Nuclear factor (NF)-kappaB is a transcriptional factor required for the gene expression of many inflammatory mediators. This study was designed to investigate the biological effects of parthenolide, a specific inhibitor of NF-kappaB activation, in experimental sepsis and multiple organ failure.

DESIGN

Prospective, randomized laboratory investigation that used an established model of cecal ligation and puncture to induce polymicrobial sepsis in rats.

SETTING

University hospital laboratory.

SUBJECTS

Male Sprague Dawley rats underwent cecal ligation and puncture followed by the administration of saline solution.

INTERVENTIONS

A group of rats received parthenolide (1 mg/kg) intraperitoneally. Mean arterial blood pressure was monitored for 18 hrs, and survival rate was monitored for 4 days. In a separate experiment, rats were killed at 1, 3, 6, and 18 hrs after cecal ligation and puncture.

MEASUREMENTS AND MAIN RESULTS

In vehicle-treated animals, cecal ligation and puncture resulted in polymicrobial sepsis and was associated with 20% mortality rate, marked hypotension, and lung injury. Immunohistochemistry showed positive staining for nitrotyrosine and poly(adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1) in thoracic aortas. There was a significant increase in plasma concentrations of tumor necrosis factor-alpha, interleukin-6, and interleukin-10. Elevated levels of myeloperoxidase activity in lung, colon, and liver were indicative of infiltration of neutrophils. These inflammatory events were associated with activation of NF-kappaB in the lung in a time-dependent fashion. In vivo treatment with parthenolide improved the hemodynamic profile and survival; reduced neutrophil infiltration in lung, colon, and liver; and reduced plasma concentrations of cytokines. Treatment with parthenolide also abolished formation of nitrotyrosine and expression of PARP-1 in thoracic aortas. These beneficial effects of parthenolide were associated with reduction of NF-kappaB activity in the lung.

CONCLUSIONS

Our data suggest that pharmacologic inhibition of NF-kappaB may represent a potential therapeutic approach in sepsis.

Corticosteroid receptors, 11 beta-hydroxysteroid dehydrogenase, and the heart

Mineralocorticoid and glucocorticoid hormones are known as corticosteroid hormones and are synthesized mainly in the adrenal cortex; however, more recently the enzymes involved in their synthesis have been found in a variety of cells and tissues, including the heart. The effects of these hormones are mediated via both cytoplasmic mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs), which act as ligand-inducible transcription factors. In addition, rapid, nongenomically mediated effects of these steroids can occur that may be via novel corticosteroid receptors. The lipophilic nature of these hormones allows them to pass freely through the cell membrane, although the intracellular concentration of mineralocorticoids and glucocorticoids is dependent on several cellular factors. The main regulators of intracellular glucocorticoid levels are 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) isoforms. 11 beta HSD1 acts predominantly as a reductase in vivo, facilitating glucocorticoid action by converting circulating receptor-inactive 11-ketoglucocorticoids to active glucocorticoids. In contrast, 11 beta HSD 2 acts exclusively as an 11 beta-dehydrogenase and decreases intracellular glucocorticoids by converting them to their receptor-inactive 11-ketometabolites. Furthermore, P-glycoproteins, by actively pumping steroids out of cells, can selectively decrease steroids and local steroid synthesis can increase steroid concentrations. Receptor concentration, receptor modification, and receptor-protein interactions can also significantly impact on the corticosteroid response. This review details the receptors and possible mechanisms involved in both mediating and modulating corticosteroid responses. In addition, direct effects of corticosteroids on the heart are described including a discussion of the corticosteroid receptors and the mechanisms involved in mediating their effects.

Effects of sesquiterpenes and amino acid-sesquiterpene conjugates from the roots of Saussurea lappa on inducible nitric oxide synthase and heat shock protein in lipopolysaccharide-activated macrophages

The methanolic extract of the roots of Saussurea lappa CLARKE, a Chinese medicinal herb Saussureae Radix, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Among the constituents from the methanolic extract, two sesquiterpene lactones (costunolide and dehydrocostus lactone) and two amino acid-sesquiterpene conjugates (saussureamines A and B) potently inhibited LPS-induced NO production (IC(50)=1.2-2.8 microM). Saussureamines A and B in addition to costunolide and dehydrocostus lactone did not inhibit iNOS enzyme activity, but they inhibited both induction of inducible NO synthase and activation of nuclear factor-kappaB in accordance with induction of heat shock protein 72.

Role of nuclear factor-kappa B activation in acute ischaemia-reperfusion injury in myocardium

(1) Our aims were to characterize activation of the transcription factor, nuclear factor kappa-B(NF-kappaB), during myocardial ischaemia-reperfusion and to assess its functional role in the evolution of acute ischaemia-reperfusion injury in intact myocardium in vivo. (2) Under pentobarbitone anaesthesia, rabbits underwent sham operation, 30 min left coronary artery occlusion followed by 0, 10 or 180 min reperfusion. Saline or NF-kappaB inhibitor diethyldithiocarbamic acid (DDTC, 50, 100 or 200 mg kg(-1)) was given intravenously 5 min prior to reperfusion. (3) Electromobility shift assay revealed that 30 min ischaemia alone did not activate NF-kappaB compared to time-matched sham-operated controls (85+/-13% vs 100+/-28%, respectively). However, ischaemia plus 10 min reperfusion markedly increased activation of NF-kappaB (295+/-77%). DDTC 50 mg kg(-1) did not inhibit NF-kappaB activation (278+/-67%) but at the higher doses complete inhibition was observed (54+/-20%, 31+/-16%, respectively). (4) Infarct to risk ratio was determined by triphenyltetrazolium chloride staining after 30 min ischaemia and 180 min reperfusion. DDTC 50 or 100 mg kg(-1) significantly reduced infarct size compared to the saline-treated control group (34.9+/-5.2%, 37.1+/-5.9%, vs 51.3+/-3.6%, P<0.05, respectively), whereas there was no protection with 200 mg kg(-1) (45.6+/-5.3%). (5) We conclude that ischaemia alone does not activate NF-kappaB, but post-ischaemic reperfusion robustly activates NF-kappaB in the myocardium. DDTC limited irreversible injury at low doses, but this effect appears to be dissociated from inhibition of NF-kappaB. Thus, activation of NF-kappaB during reperfusion does not appear to play a role in the evolution of myocardial infarction during the early phase of reperfusion.

Nuclear factor-kappaB as a therapeutic target in critical care medicine

Nuclear factor-kappaB is a transcriptional factor required for the gene expression of many inflammatory mediators. Nuclear factor-kappaB activation requires removal and degradation of its inhibitor kappaB, an event that occurs after phosphorylation of inhibitor kappaB by a complex of inhibitor kappaB kinases. These events allow nuclear factor-kappaB to translocate into the nucleus, where it binds to kappaB elements and initiates transcription. Inappropriate and prolonged activation of nuclear factor-kappaB has been linked to several diseases associated with inflammatory events, including septic shock, acute respiratory distress syndrome, ischemia, and reperfusion injury. Thus, the key role of nuclear factor-kappaB in regulating inflammation makes this factor a therapeutic target for reducing tissue and organ damage. Regulation and control of nuclear factor-kappaB can be achieved by gene modification strategies or by pharmacologic inhibition of the key components of the cascade that leads to nuclear factor-kappaB activation. The purpose of our review is to describe these novel therapeutic approaches and their potential efficacy.

Parthenolide, an inhibitor of the nuclear factor-kappaB pathway, ameliorates cardiovascular derangement and outcome in endotoxic shock in rodents

Parthenolide is a sesquiterpene lactone used in folk medicine for its anti-inflammatory activity. Recent in vitro studies have shown that this compound inhibits the nuclear factor (NF)-kappaB pathway. This study examines the effect of parthenolide in endotoxic shock in rodents. Endotoxic shock was induced by administration of Escherichia coli endotoxin in rats. Three groups of rats received parthenolide (0.25, 0.5, or 1 mg/kg) 15 min before endotoxin; another group received parthenolide (1 mg/kg) 3 h after endotoxin. In vehicle-treated rats, administration of endotoxin caused severe hypotension, which was associated with a marked hyporeactivity to norepinephrine in ex vivo thoracic aortas. Immunohistochemistry showed positive staining for nitrotyrosine, poly(ADP-ribose) synthetase (PARS) and apoptosis, whereas Northern blot analysis showed increased mRNA expression of inducible nitric-oxide synthase (iNOS) in thoracic aortas. Elevated levels of plasma nitrate/nitrite were also found. Elevated lung levels of myeloperoxidase activity were indicative of infiltration of neutrophils. These inflammatory events were preceded by cytosolic degradation of inhibitor kappaBalpha (IkappaBalpha) and activation of nuclear NF-kappaB in the lung. In vivo pretreatment and post-treatment with parthenolide improved the hemodynamic profile and reduced plasma nitrate/nitrite and lung neutrophil infiltration in a dose-dependent fashion. Vascular hyporeactivity of ex vivo aortas was ameliorated. Treatment with parthenolide also abolished nitrotyrosine formation, PARS expression, and apoptosis and reduced iNOS mRNA content in thoracic aortas. DNA binding of NF-kappaB was inhibited by parthenolide in the lung, whereas degradation of IkappaBalpha was unchanged. In a separate set of experiments, pretreatment or post-treatment with parthenolide significantly improved survival in mice challenged with endotoxin. We conclude that parthenolide exerts beneficial effects during endotoxic shock through inhibition of NF-kappaB.

Absence of inducible nitric oxide synthase modulates early reperfusion-induced NF-kappaB and AP-1 activation and enhances myocardial damage

The role of nitric oxide (NO) generated by the inducible NO synthase (iNOS) during myocardial ischemia and reperfusion is not understood. We investigated the role of iNOS during early reperfusion damage induced in genetically deficient iNOS (iNOS-/-) mice and wild-type littermates. In wild-type mice, ischemia (60 min) and reperfusion (60 min) induced an elevation in serum levels of creatine phosphokinase and myocardial injury characterized by the presence of scattered apoptotic myocytes and mild neutrophil infiltration. Northern blot analysis showed increased expression of iNOS, whose activity was markedly elevated after reperfusion. Immunohistochemistry showed staining for nitrotyrosine; Western blot analysis showed elevated expression of heat shock protein 70 (HSP70), a putative cardioprotective mediator. Plasma levels of nitrite and nitrate, tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and IL-10 were also increased. These events were preceded by degradation of inhibitor kappaBalpha (IkappaBalpha), activation of IkappaB kinase complex (IKK) and c-Jun-NH2-terminal kinase (JNK), and subsequently activation of nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) as early as 15 min after reperfusion. In contrast, iNOS-/- mice experienced 35% mortality after reperfusion. The extensive myocardial injury was associated with marked apoptosis and infiltration of neutrophils whereas expression of HSP70 was less pronounced. Nitrotyrosine formation and plasma levels of nitrite and nitrate were undetectable. TNF-alpha and IL-6 were increased and IL-10 was reduced in earlier stages of reperfusion. Activation of IKK and JNK and binding activity of NF-kappaB and AP-1 were significantly reduced. Thus, we conclude that iNOS plays a beneficial role in modulating the early defensive inflammatory response against reperfusion injury through regulation of signal transduction.