Signal transduction pathways of apoptosis and inflammation induced by the tumor necrosis factor receptor family

Enhancement of cardiac angiogenesis in a myocardial infarction rat model using selenium alone and in combination with PTXF: the role of Akt/HIF-1α signaling pathway

Ischemic heart diseases such as myocardial infarction (MI) are a global health problem and a leading cause of mortality worldwide. Angiogenesis is an important approach for myocardial healing following ischemia. Thus, this study aimed to explore the potential cardiac angiogenic effects of selenium (Se), alone and in combination with the tumor necrosis factor-alpha inhibitor, pentoxifylline (PTXF), via Akt/HIF-1α signaling. MI was induced in rats using two subcutaneous doses of isoprenaline (ISP) at a 24-h interval (150 mg/kg). One week later, rats were orally given Se (150 µg/kg/day), PTXF (50 mg/kg/day), or Se/PTXF combination. ISP-induced myocardial damage was evident by increased HW/TL ratios, ST segment elevation, and increased serum levels of CK-MB, LDH, and troponin-I. ISP increased the cardiac levels of the lipid peroxidation marker MDA; the pro-inflammatory cytokines IL-6, IL-1β, and TNF-α; and the pro-apoptotic protein Bax and caspase-3. In contrast, the cardiac levels of the antioxidant markers GSH and SOD and the anti-apoptotic marker Bcl-2 were reduced. Furthermore, ISP markedly increased the cardiac levels of p-Akt and HIF-1α proteins and the cardiac gene expression of ANGPT-1, VEGF, and FGF-2. Treatment with Se both alone and in combination with PTXF ameliorated the ISP-induced myocardial damage and further increased cardiac angiogenesis via Akt/HIF-1α signaling. Se/PTXF combined therapy was more beneficial than individual treatments. Our study revealed for the first time the cardiac angiogenic effects of Se both alone and in combination with PTXF in myocardial infarction, suggesting that both may be promising candidates for clinical studies.

Physiological and transcriptomic responses of seawater halobios to micro/nano-scale polystyrene-cadmium exposure in a marine food web

Micro/nano-plastics (MPs/NPs) represent an emerging contaminant, posing a significant threat to oceanic halobios. While the adverse effects of joint pollutants on marine organisms are well-documented, the potential biological impacts on the food chain transmission resulting from combinations of MPs/NPs and heavy metals (HMs) remain largely unexplored. This study exposed the microbial loop to combined contaminants (MPs/NPs + HMs) for 48h, bacteria and contaminants are washed away before feeding to the traditional food chain, employing microscopic observation, biochemical detection, and transcriptome analysis to elucidate the toxicological mechanisms of the top predator. The findings revealed that MPs/NPs combined with Cd2+ could traverse both the microbial loop and classical food chain. Acute exposure significantly affected the carbon biomass of the top predator Tigriopus japonicus (75.8% lower). Elevated antioxidant enzyme activity led to lipid peroxidation, manifesting in increased malondialdehyde levels. Transcriptome sequencing showed substantial differential gene expression levels in T. japonicus under various treatments. The upregulation of genes associated with apoptosis and inflammatory responses, highlighting the impact of co-exposure on oxidative damage and necroptosis within cells. Notably, NPs-Cd exhibited stronger toxicity than MPs-Cd. NPs-Cd led to a greater decrease in the biomass of top predators, accompanied by lower activities of GSH, SOD, CAT, and GSH-PX, resulting in increased production of lipid peroxidation product MDA and higher oxidative stress levels. This investigation provides novel insights into the potential threats of MPs/NPs combined with Cd2+ on the microbial loop across traditional food chain, contributing to a more comprehensive assessment of the ecological risks associated with micro/nano-plastics and heavy metals.

Intermittent mild cold acclimation ameliorates intestinal inflammation and immune dysfunction in acute cold-stressed broilers by regulating the TLR4/MyD88/NF-κB pathway

To investigate the potential protective effect of prior cold stimulation on broiler intestine induced by acute cold stress (ACS). A total of 384 one-day-old broilers were divided into control (CON), ACS, cold stimulation Ⅰ (CS3+ACS), and cold stimulation Ⅱ (CS9+ACS) groups. Broilers in CON and ACS groups were reared normally, and birds in CS3+ACS and CS9+ACS groups were reared at 3℃ and 9℃ below CON group for 5 h, respectively, on alternate days from d 15 to 35. Broilers in ACS, CS3+ACS, and CS9+ACS groups were subjected to 10℃ for 24 h on d 43. Eventually, small intestine tissues were collected for histopathological observation and indexes detection. The results showed that intestinal tissues in all ACS-broilers exhibited inflammatory cell infiltrates, microvilli disruption, reduced villus length in jejunum and increased crypt depth in jejunum and ileum. Whereas these phenomena were relatively light in CS3+ACS group. Compared to CON group, mRNA expression of the TLR4/MyD88/NF-κB pathway-related genes (TLR4, MyD88, NF-κBp65, COX-2, iNOS, PTGEs, TNF-α), Th1/Th17-derived cytokines (IL-1β, IL-2, IL-8, IL-12, IFN-γ, IL-17), and HSPs (HSP40, HSP60, HSP70, HSP90) was upregulated (P < 0.05), and that of Th2-deviated cytokines (IL-4, IL-6, IL-10, IL-13) and IκBα was downregulated (P < 0.05) in small intestine in almost all ACS-broilers. Compared to ACS group, mRNA expression of most of the TLR4/MyD88/NF-κB pathway-related genes, Th1/Th17-derived cytokines, and HSPs was downregulated and that of Th2-derived cytokines was upregulated in CS3+ACS group (P < 0.05). Protein expression levels of TLR4, MyD88, p-p65/p65, p-IκBα/IκBα, IKK, TNF-α, IL-1β, IL-10, and HSPs were similar to their mRNA expression. The concentration of sIgA and activities of CAT, SOD, and GSH-px were decreased and MDA and H2O2 were increased in ACS and CS9+ACS groups compared to CON group (P < 0.05). Therefore, cold stress caused oxidative stress and inflammation, leading to gut immune dysfunction; while mild cold stimulation at 3℃ below normal rearing temperature alleviated cold stress-induced intestinal injure and dysfunction by modulating the TLR4/MyD88/NF-κB pathway in broilers.

Ensemble-based molecular docking and spectrofluorometric analysis of interaction between cytotoxin and tumor necrosis factor receptor 1

Cytotoxin (CTX) is a three-finger toxin presents predominantly in cobra venom. The functional site of the toxin is located at its three hydrophobic loop tips. Its actual mechanism of cytotoxicity remains inconclusive as few conflicting hypotheses have been proposed in addition to direct cytolytic effects. The present work investigated the interaction between CTX and death receptor families via ensemble-based molecular docking and fluorescence titration analysis. Multiple sequence alignments of different CTX isoforms obtained a conserved CTX sequence. The three-dimensional structure of the conserved CTX was later determined using homology modelling, and its quality was validated. Ensemble-based molecular docking of CTX was performed with different death receptors, such as Fas-ligand and tumor necrosis factor receptor families. Our results showed that tumor necrosis factor receptor 1 (TNFR1) was the best receptor interacting with CTX attributed to the interaction of all three functional loops and evinced with low HADDOCK, Z-score and RMSD value. The interaction between CTX and TNFR1 was also supported by a concentration-dependent reduction of fluorescence intensity with increasing binding affinity. The possible intermolecular interactions between CTX and TNFR1 were Van der Waals forces and hydrogen bonding. Our findings suggest a possibility that CTX triggers apoptosis cell death through non-covalent interactions with TNFR1.Communicated by Ramaswamy H. Sarma.

Pathogenesis of sarcopenia in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common pulmonary disease characterized by persistent respiratory symptoms and airflow obstruction. In addition to lung diseases, chronic obstructive pulmonary disease (COPD) is often associated with other organ diseases, and sarcopenia is one of the common diseases. In recent years, multiple factors have been proposed to influence muscle dysfunction in COPD patients, including systemic and local inflammation, oxidative stress, hypoxia, hypercapnia, protein synthesis, catabolic imbalance, nutritional changes, disuse, ageing, and the use of medications such as steroids. These factors alone or in combination can lead to a reduction in muscle mass and cross-sectional area, deterioration of muscle bioenergy metabolism, defects in muscle repair and regeneration mechanisms, apoptosis and other anatomical and/or functional pathological changes, resulting in a decrease in the muscle’s ability to work. This article reviews the research progress of possible pathogenesis of sarcopenia in COPD.

Diaphragm Dysfunction and Rehabilitation Strategy in Patients With Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) affects the whole body and causes many extrapulmonary adverse effects, amongst which diaphragm dysfunction is one of the prominent manifestations. Diaphragm dysfunction in patients with COPD is manifested as structural changes, such as diaphragm atrophy, single-fibre dysfunction, sarcomere injury and fibre type transformation, and functional changes such as muscle strength decline, endurance change, diaphragm fatigue, decreased diaphragm mobility, etc. Diaphragm dysfunction directly affects the respiratory efficiency of patients and is one of the important pathological mechanisms leading to progressive exacerbation of COPD and respiratory failure, which is closely related to disease mortality. At present, the possible mechanisms of diaphragm dysfunction in patients with COPD include systemic inflammation, oxidative stress, hyperinflation, chronic hypoxia and malnutrition. However, the specific mechanism of diaphragm dysfunction in COPD is still unclear, which, to some extent, increases the difficulty of treatment and rehabilitation. Therefore, on the basis of the review of changes in the structure and function of COPD diaphragm, the potential mechanism of diaphragm dysfunction in COPD was discussed, the current effective rehabilitation methods were also summarised in this paper. In order to provide direction reference and new ideas for the mechanism research and rehabilitation treatment of diaphragm dysfunction in COPD.

From Bed to Bench and Back: TNF-α, IL-23/IL-17A, and JAK-Dependent Inflammation in the Pathogenesis of Psoriatic Synovitis

Psoriatic arthritis (PsA) is a chronic inflammatory immune-mediated disease with a burdensome impact on quality of life and substantial healthcare costs. To date, pharmacological interventions with different mechanisms of action, including conventional synthetic (cs), biological (b), and targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARDs), have been proven efficacious, despite a relevant proportion of failures. The current approach in clinical practice and research is typically "predictive": the expected response is based on stratification according to clinical, imaging, and laboratory data, with a "heuristic" approach based on "trial and error". Several available therapeutic options target the TNF-α pathway, while others are directed against the IL-23/IL-17A axis. Janus kinase inhibitors (JAKis), instead, simultaneously block different pathways, endowing these drugs with a potentially "broad-spectrum" mechanism of action. It is not clear, however, whether targeting a specific pathway (e.g., TNF-α or the IL-23/IL-17 axis) could result in discordant effects over other approaches. In particular, in the case of "refractory to a treatment" patients, other pathways might be hyperactivated, with opposing, synergistic, or redundant biological significance. On the contrary, refractory states could be purely resistant to treatment as a whole. Since chronic synovitis is one of the primary targets of inflammation in PsA, synovial biomarkers could be useful in depicting specific biological characteristics of the inflammatory burden at the single-patient level, and despite not yet being implemented in clinical practice, these biomarkers might help in selecting the proper treatment. In this narrative review, we will provide an up-to-date overview of the knowledge in the field of psoriatic synovitis regarding studies investigating the relationships among different activated proinflammatory processes suitable for targeting by different available drugs. The final objective is to clarify the state of the art in the field of personalized medicine for psoriatic disease, aiming at moving beyond the current treatment schedules toward a patient-centered approach.

The Effects of Volatile Anesthetics on Lung Ischemia-Reperfusion Injury: Basic to Clinical Studies

Case reports from as early as the 1970s have shown that intravenous injection of even a small dose of volatile anesthetics result in fatal lung injury. Direct contact between volatile anesthetics and pulmonary vasculature triggers chemical damage in the vessel walls. A wide variety of factors are involved in lung ischemia-reperfusion injury (LIRI), such as pulmonary endothelial cells, alveolar epithelial cells, alveolar macrophages, neutrophils, mast cells, platelets, proinflammatory cytokines, and surfactant. With a constellation of factors involved, the assessment of the protective effect of volatile anesthetics in LIRI is difficult. Multiple animal studies have reported that with regards to LIRI, sevoflurane demonstrates an anti-inflammatory effect in immunocompetent cells and an anti-apoptotic effect on lung tissue. Scattered studies have dismissed a protective effect of desflurane against LIRI. While a single-center randomized controlled trial (RCT) found that volatile anesthetics including desflurane demonstrated a lung-protective effect in thoracic surgery, a multicenter RCT did not demonstrate a lung-protective effect of desflurane. LIRI is common in lung transplantation. One study, although limited due to its small sample size, found that the use of volatile anesthetics in organ procurement surgery involving "death by neurologic criteria" donors did not improve lung graft survival. Future studies on the protective effect of volatile anesthetics against LIRI must examine not only the mechanism of the protective effect but also differences in the effects of different types of volatile anesthetics, their optimal dosage, and the appropriateness of their use in the event of marked alveolar capillary barrier damage.

The effects of chrysin on lipopolysaccharide-induced sepsis in rats

Chrysin (CR) is a flavone found in propolis and many plants. Lipopolysaccharide (LPS) is a component of the cell wall of gram-negative bacteria that causes sepsis. The purpose of this study was to investigate the effects of CR on LPS-induced sepsis in rats. LPS intraperitoneal and a single dose and CR were given orally for 10 days. Rats were sacrificed, blood samples were taken, liver, lung, and kidney tissues were dissected, homogenized, and histopathological analysis was carried out. When CR groups compared to sepsis group, CR significantly decreased the serum levels of aspartate transaminase (AST) and alanine aminotransferase (ALT), interleukin-1 beta (IL-1β), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and levels of malondialdehyde (MDA) in tissues. CR also increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in tissues. Histopathological findings were consistent with biochemical findings. Conclusion, CR could reduce the oxidative stress markers and cytokines in sepsis. PRACTICAL APPLICATIONS: Our approach is to determine the antioxidant and anti-inflammatory effects of chrysin, known as a flavolonoid, which are found in many plants and foods such as honey and propolis. In this study, experimental sepsis model was created using LPS. According to the results of the study, CR can attribute to the ameliorating of oxidative damage in tissues (lung, liver, and kidney) and it can suppress the sepsis-associated acute tissue injury via reduction of inflammation in rats. Even, CR can be used as a pharmacological agent in inflammatory diseases caused by other sources and in many cases causing oxidation.

Apoptotic cell-derived exosomes: messages from dying cells

Apoptosis, a type of programmed cell death that plays a key role in both healthy and pathological conditions, releases extracellular vesicles such as apoptotic bodies and microvesicles, but exosome release due to apoptosis is not yet commonly accepted. Here, the reports demonstrating the presence of apoptotic exosomes and their roles in inflammation and immune responses are summarized, together with a general summary of apoptosis and extracellular vesicles. In conclusion, apoptosis is not just a 'silent' type of cell death but an active form of communication from dying cells to live cells through exosomes.

The first cloned echinoderm tumor necrosis factor receptor from Holothuria leucospilota: Molecular characterization and functional analysis

In this study, an echinoderm tumor necrosis factor receptor named HLTNFR-16 was first cloned from the tropical sea cucumber Holothuria leucospilota. The full-length cDNA of HLTNFR-16 is 3675 bp in size, containing a 415 bp 5'-untranslated region (UTR), a 2024 bp 3'-UTR and a 1236 bp open reading frame (ORF) encoding a protein of 411 amino acids with a deduced molecular weight of 45.63 kDa. The HLTNFR-16 protein contains a signal peptide, four TNFR domains (the last three were identified as extracellular cysteine-rich domains), a transmembrane region and a death domain. Phylogenetic analysis showed that HLTNFR-16 was clustered into a clade with TNFR-16s in other species, indicating that this echinoderm TNFR may be a new member of the TNFR-16 subfamily. The results of TUNEL assay showed that the over expression of HLTNFR-16 could induce apoptosis in HEK293T cells. When HLTNFR-16 was silenced by siRNA, the apoptosis of sea cucumber coelomocytes induced by inactivated Vibrio harveyi was suppressed significantly, indicating that HLTNFR-16 is important for apoptosis induction. Additionally, luciferase reporter assay exhibited that the over-expressed HLTNFR-16 in HEK293T cells could activate the transcription factors nuclear factor-κB (NF-κB) and activator protein-1 (AP-1). Moreover, the secretion of proinflammatory cytokines interleukin (IL)-1β, IL-6 and IL-18 in HEK293T cells was increased by the over-expression of HLTNFR-16. This study provides evidences for the potential roles of sea cucumber TNFR in the innate immunity.

Molecular mechanisms of biogenesis of apoptotic exosome-like vesicles and their roles as damage-associated molecular patterns

Recent research has led to contradictory notions regarding the conventional theory that apoptotic cell death can evoke inflammatory or immunogenic responses orchestrated by released damage-associated patterns (DAMPs). By inducing IL-1β from bone marrow-derived macrophages in an effort to determine the inflammatory mediators released from apoptotic cells, we found that exosomal fractions called "apoptotic exosome-like vesicles" (AEVs) prepared from apoptotic-conditioned medium were the main inflammatory factors. These AEVs showed characteristics of exosomes in their size, density, morphology, and protein expression but had unique marker proteins, sphingosine-1-phosphate receptors 1 and 3 (S1PR1 and 3). Their biogenesis was completely dependent on cellular sphingosine-1-phosphate (S1P)/S1PRs signaling from multiple fine spindles of plasma membrane accompanied by F-actin, S1PR1, S1PR3, and CD63 at the early apoptotic phase and progressing to the maturation of F-actin-guided multivesicular endosomes mediated by Gβγ subunits of S1PRs downstream. S1P-loaded S1PRs on AEVs were critical factors for inducing IL-1β via NF-κB transcriptional factor and p38 MAPK, possibly through the RHOA/NOD2 axis, in differentiating macrophages. The AEVs induced genes of proinflammatory cytokines, chemokines, and mediators in both in vitro and in vivo models. In conclusion, AEVs could be key inflammatory mediators, acting as DAMPs that could explain the pathogeneses of various chronic inflammations, autoimmune diseases, or cancers in the future.

Low tidal volume ventilation preconditioning ameliorates lipopolysaccharide-induced acute lung injury in rats

BACKGROUND

Effects of low tidal volume (LTV) ventilation preconditioning in endotoxin-induced acute lung injury (ALI) have not been studied. We investigated the effect of LTV ventilation pre-treatment on ALI induced by lipopolysaccharide (LPS) in rats.

METHODS

Male Sprague-Dawley rats were assigned to four groups (n = 8 each): (1) sham rats injected (i.p.) with 0.9% (physiologic) saline; sham rats pre-treated with tidal volume 6 ml/kg ventilation for 1 h followed by injection (i.p.) of physiologic saline (mechanical ventilation; MV-saline group); (2) LPS group (rats injected with LPS (i.p.); rats pre-treated with tidal volume 6 ml/kg ventilation for 1 h before injection (i.p.) with LPS (MV-LPS group). Animals were observed for 6 h. ALI extent was evaluated by lung wet-to-dry ratio, Evans Blue Dye extravasation, and histologic examination. We measured levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. Apoptotic index (AI) and the expression of pulmonary RhoA, ROCK2 mRNA, and ROCK1 protein in lung alveolar cells was determined.

RESULTS

Lipopolysaccharide caused severe ALI, as evidenced by increases in ALI extent, impairment of pulmonary functions, and increases in pulmonary levels of TNF-α, IL-1β, IL-6, and AI. LTV ventilation preconditioning mitigated LPS-induced increases in release of pulmonary pro-inflammatory cytokines and AI of alveolar cells. Expression of pulmonary RhoA, ROCK2 mRNA, and ROCK1 protein was upregulated by LPS and reduced by LTV ventilation pre-treatment.

CONCLUSION

Low tidal volume ventilation preconditioning can attenuate release of pulmonary pro-inflammatory cytokines and decrease the AI induced by severe sepsis. Early protection seems to be mediated partly through inhibition of activation of a Rho pathway.

Reverse Epidemiology of Traditional Cardiovascular Risk Factors in the Geriatric Population

Traditional risk factors of cardiovascular death in the general population, including body mass index (BMI), serum cholesterol, and blood pressure (BP), are also found to relate to outcomes in the geriatric population, but in an opposite direction. Some degrees of elevated BMI, serum cholesterols, and BP are reportedly associated with lower, instead of higher, risk of death among the elderly. This phenomenon is termed "reverse epidemiology" or "risk factor paradox" (such as obesity paradox) and is also observed in a variety of chronic disease states such as end-stage renal disease requiring dialysis, chronic heart failure, rheumatoid arthritis, and AIDS. Several possible causes are hypothesized to explain this risk factor reversal: competing short-term and long-term killers, improved hemodynamic stability in the obese, adipokine protection against tumor necrosis factor-α, lipoprotein protection against endotoxins, and lipophilic toxin sequestration by the adipose tissue. It is possible that the current thresholds for intervention and goal levels for such traditional risk factors as BMI, serum cholesterol, and BP derived based on younger populations do not apply to the elderly, and that new levels for such risk factors should be developed for the elderly population. Reverse epidemiology of conventional cardiovascular risk factors may have a bearing on the management of the geriatric population, thus it deserves further attention.

Oxidative stress by monosodium urate crystals promotes renal cell apoptosis through mitochondrial caspase-dependent pathway in human embryonic kidney 293 cells: mechanism for urate-induced nephropathy

The aim of this study is to clarify the effect of oxidative stress on monosodium urate (MSU)-mediated apoptosis of renal cells. Quantitative real-time polymerase chain reaction and immunoblotting for Bcl-2, caspase-9, caspase-3, iNOS, cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), IL-18, TNF receptor-associated factor-6 (TRAF-6), and mitogen-activated protein kinases were performed on human embryonic kidney 293 (HEK293) cells, which were stimulated by MSU crystals. Fluorescence-activated cell sorting was performed using annexin V for assessment of apoptosis. Reactive oxygen species (ROS) were measured. IL-1β siRNA was used for blocking IL-1β expression. MSU crystals promoted ROS, iNOS, and COX-2 expression and also increased TRAF-6 and IL-1β expression in HEK293 cells, which was inhibited by an antioxidant ascorbic acid. Caspase-dependent renal cell apoptosis was induced through attenuation of Bcl-2 and enhanced caspase-3 and caspase-9 expression by MSU crystals, which was significantly reversed by ascorbic acid and transfection of IL-1β siRNA to HEK293 cells. Ascorbic acid inhibited phosphorylation of extracellular signal-regulated kinase and Jun N-terminal protein kinase stimulated by MSU crystals. ROS accumulation and iNOS and COX-2 mRNA expression by MSU crystals was also suppressed by transfection with IL-1β siRNA. Oxidative stress generated by MSU crystals promotes renal apoptosis through the mitochondrial caspase-dependent apoptosis pathway.

Oxidative Stress and Lung Ischemia-Reperfusion Injury

Ischemia-reperfusion (IR) injury is directly related to the formation of reactive oxygen species (ROS), endothelial cell injury, increased vascular permeability, and the activation of neutrophils and platelets, cytokines, and the complement system. Several studies have confirmed the destructiveness of the toxic oxygen metabolites produced and their role in the pathophysiology of different processes, such as oxygen poisoning, inflammation, and ischemic injury. Due to the different degrees of tissue damage resulting from the process of ischemia and subsequent reperfusion, several studies in animal models have focused on the prevention of IR injury and methods of lung protection. Lung IR injury has clinical relevance in the setting of lung transplantation and cardiopulmonary bypass, for which the consequences of IR injury may be devastating in critically ill patients.

Exogenous α-calcitonin gene-related peptide attenuates lipopolysaccharide-induced acute lung injury in rats

α-Calcitonin gene-related peptide (α-CGRP) is a 37 amino-acid neuropeptide that is primarily released from C-type sensory neurons. α-CGRP exerts multiple modulatory effects on immune responses and visceral organ function, but the role of exogenous α-CGRP in lipopolysaccharide (LPS)-induced acute lung injury (ALI) has remained to be elucidated. Forty-eight rats were randomized to receive continuous intraperitoneal infusion of α-CGRP (0.4 μg/kg/min) or normal saline for 30 min, followed by intratracheal injection of 0.5 mg/kg LPS or saline. There were four groups of animals: The saline-saline (S-S) group; the saline-α-CGRP (S-C) group; the LPS-saline (L-S) group and the LPS-α-CGRP (L-C) group. Mean arterial pressure and arterial blood gases were assessed prior to α-CGRP and LPS administration and every hour following LPS treatment. After 4 h, bronchoalveolar lavage was performed and used to assess total cell count and levels of tumor necrosis factor-α, interleukin-1β, intracellular cell adhesion molecule 1 and macrophage inflammatory protein 2. Lung tissue was also collected for assessing wet-to-dry (W/D) ratio, histology and Evans blue (EB) dye extravasation. Pulmonary α-CGRP concentration and α-CGRP receptor expression were also examined, and inducible cyclic adenosine monophosphate early repressor (ICER) and TNF-α mRNA expression levels were measured. Treatment with exogenous α-CGRP improved oxygenation during LPS-induced ALI. Correspondingly, histological injury, total cell count, inflammatory cytokine levels, W/D ratio and EB dye extravasation were also significantly reduced. α-CGRP receptor 1 expression was noted in pulmonary endothelial cells and alveolar macrophages and α-CGRP receptor expression levels were decreased during ALI, whereas pulmonary α-CGRP expression was continuously increased. Furthermore, exogenous α-CGRP induced upregulation of ICER during LPS-induced ALI. In conclusion, exogenous α-CGRP improved oxygenation and ameliorated lung damage in LPS-induced ALI, and these effects were associated with the upregulation of ICER.

Combination therapy with human umbilical cord mesenchymal stem cells and angiotensin-converting enzyme 2 is superior for the treatment of acute lung ischemia-reperfusion injury in rats

Acute lung ischemia-reperfusion injury (ALIRI) is a serious disease that seriously affects human's life. In this study, we aimed to explore a more effective treatment method by combining human umbilical cord mesenchymal stem cells (HUMSCs) and angiotensin-converting enzyme 2 (ACE2) for ALIRI. Fifty rats were firstly divided into five groups, namely sham surgery group (sham) and four model groups (model, ACE2, HUMSCs and HUMSCs + ACE2) that were reperfused with 0.1 ml physiological saline (PS), 0.1 ml PS containing 1 × 10(6) lentiviral-ACE2/HUMSCs/ACE2 + UMSCs, respectively. Quantitative reverse transcription-PCR (qRT-PCR) and western blot assays were then conducted to detect the messenger RNA (mRNA) and protein levels of inflammatory cytokines [intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), tumour necrosis factor α (TNF-α), nuclear factor κB (NF-κB), platelet-derived growth factor (PDGF) and angiotensin II (Ang II)], antioxidant proteins [NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HO-1)], DNA damage and apoptotic indicators [BCL2-associated X (Bax), cleaved caspase-3 (C-Csp 3), cleaved-poly(ADP-ribose) polymerase (C-PARP), Y-H2AX], anti-apoptotic indicator (Bcl-2) and smooth muscle cell proliferation indicator [connexin 43 (Cx43)]. According to the qRT-PCR and western results, the mRNA and protein expression levels of ICAM-1, VCAM-1, TNF-α, NF-κB, PDGF, Bax, C-Csp 3, C-PARP and Y-H2AX were significantly higher in model group than those in sham group and they were significantly reduced by HUMSCs or ACE2 treatment (P < 0.05). On the contrary, Bcl-2 showed an opposite expression trend with the previous proteins. The mRNA and protein levels of NQO1 and HO-1 were sequentially increased in sham, model, ACE2, HUMSCs and HUMSCs + ACE2 groups. Besides, HUMSCs combined with ACE2 exhibited a better inhibition effect on ALIRI than HUMSCs or ACE2 alone (P < 0.05). In summary, HUMSCs combined with ACE2 was demonstrated to have the best therapeutic effect on ALIRI through anti-inflammation, oxidative stress and anti-apoptotic processes.

Polymorphisms of tumor necrosis factor-alpha and interleukin-6 gene and C-reactive protein profiles in patients with idiopathic dilated cardiomyopathy

BACKGROUND AND OBJECTIVES

The tumor necrosis factor-alpha (TNF-a) and interleukin (IL)-6 gene polymorphism has a controversial role in the pathogenesis of cardiovascular disease among different populations. The effect of the cytokine's gene polymorphism on idiopathic dilated cardiomyopathy (IDCM) is still unresolved. The current study aimed to evaluate the association of the TNF-a -308 G/A and IL-6 -174 G/C polymorphism with IDCM in a Pakistani population.

DESIGN AND SETTINGS

Blood samples for this case-control study were collected from the cardiology out.patient department of multiple cardiology centers of Rawalpindi/Islamabad, Pakistan, between July 2012 and December 2012.

PATIENTS AND METHODS

IDCM cases (number [n]=250) and healthy controls (n=300) were genotyped using polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

The TNF-a -308 variant genotypes GA and AA were more prevalent in patients compared with the control group (P < .0001). Similarly, the IL-6 -174 variant genotypes GC and CC showed a high prevalence in patients with IDCM compared with healthy controls (P=.0019). IDCM cases had a higher prevalence of the TNFa-308A (P < .0001) and the IL-6 -174C (P=.0008) mutant alleles than did the control group. The IDCM cases bearing the TNF-a-308 and IL-6 variant genotypes revealed elevated levels of high-sensitivity C-reactive protein (hs-CRP) when compared with the corresponding controls (P < .05).

CONCLUSION

The TNF-a -308 G/A and IL-6 -174 G/C gene polymorphisms and high levels of hs-CRP may be associated with the pathogenesis of IDCM in the study population.

Apoptosis and inflammation associated gene expressions in monocrotaline-induced pulmonary hypertensive rats after bosentan treatment

Background and Objectives

Vascular wall remodeling in pulmonary hypertension can be caused by an aberration in the normal balance between proliferation and apoptosis of endothelial cell in the pulmonary artery. The objective of this study was to evaluate the effect of bosentan on apoptosis in monocrotaline (MCT)-induced pulmonary hypertension.

Materials and Methods

Sprague-Dawley rats were divided into three groups: control (C) group, M group (MCT 60 mg/kg) and B group (MCT 60 mg/kg plus bosentan 20 mg/day orally). Gene expressions of Bcl (B cell leukemia/lymphoma)-2, caspase-3, complement component (C)-6, vascular endothelial growth factor (VEGF), interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) were analyzed by real time polymerase chain reaction and western blot analysis.

Results

The messenger ribonucleic acid (mRNA) expressions of caspase-3 and VEGF were significantly increased in the M group compared with the C group, and significantly decreased in the B group compared with the M group in week 4. mRNA expression of IL-6 was significantly decreased in weeks 1, 2, and 4 in the B group compared with the M group. mRNA expression of TNF-α was significantly decreased on day 5 and in weeks 1 and 2 in the B group compared with the M group.

Conclusion

Bosentan may have potential for preventing apoptosis and inflammation.

Combined analysis of gamma-H2AX/53BP1 foci and caspase activation in lymphocyte subsets detects recent and more remote radiation exposures

Analysis of gamma-H2AX foci in blood lymphocytes is a promising approach for rapid dose estimation to support patient triage after a radiation accident but has one major drawback: the rapid decline of foci levels post-exposure cause major uncertainties in situations where the exact timing between exposure and blood sampling is unknown. To address this issue, radiation-induced apoptosis (RIA) in lymphocytes was investigated using fluorogenic inhibitors of caspases (FLICA) as an independent biomarker for radiation exposure, which may complement the gamma-H2AX assay. Ex vivo X-irradiated peripheral blood lymphocytes from 17 volunteers showed dose- and time-dependent increases in radiation-induced apoptosis over the first 3 days after exposure, albeit with considerable interindividual variation. Comparison with gamma-H2AX and 53BP1 foci counts suggested an inverse correlation between numbers of residual foci and radiation-induced apoptosis in lymphocytes at 24 h postirradiation (P = 0.007). In T-helper (CD4), T-cytotoxic (CD8) and B-cells (CD19), some significant differences in radiation induced DSBs or apoptosis were observed, however no correlation between foci and apoptosis in lymphocyte subsets was observed at 24 h postirradiation. While gamma-H2AX and 53BP1 foci were rapidly induced and then repaired after exposure, radiation-induced apoptosis did not become apparent until 24 h after exposure. Data from six volunteers with different ex vivo doses and post-exposure times were used to test the capability of the combined assay. Results show that simultaneous analysis of gamma-H2AX and radiation-induced apoptosis may provide a rapid and more accurate triage tool in situations where the delay between exposure and blood sampling is unknown compared to gamma-H2AX alone. This combined approach may improve the accuracy of dose estimations in cases where blood sampling is performed days after the radiation exposure.

Induction of apoptosis of malignant gliomas cells by a prenylated chalcone

Abstract Context: Malignant gliomas are the most commonly diagnosed brain tumors in adults. Chalcone and its derivatives have shown potential against glioblastoma and malignant gliomas. Objective: The inhibitory activity of geranyl prenylated chalcone was investigated in four glioma cell lines: C6, U87 MB, CNS-1 and 13-06 MB. Cell death caused by the prenylated chalcone was determined to be necrosis or apoptosis. Materials and methods: The inhibitory activity of geranyl prenylated chalcone with 5, 10, 15, 20, 25, 30 and 40 μg/ml (treatment time: 24, 48 and 72 h) was investigated in C6, U87 MB, CNS-1 and 13-06 MB. Cell cycle distribution, DNA fragmentation, chromatin condensation and protein expression were used as indicators of apoptosis. The migration ability of glioma cells with 30 μg/ml prenylated chalcone after 24 and 36 h incubation was also studied by the scratch wound assay. Results: After 24 h, treatment with 20 μg/ml prenylated chalcone reduced the proliferation (approximately 50%) of all four glioma cell lines (half maximal inhibitory concentration (IC50) = 20 μg/ml). Glioma cell death was verified by the fluorescence-activated cell sorter as prenylated chalcone-induced apoptosis. After running the analysis of protein expression, apoptotic activity induced by the prenylated chalcone was caspase independent for the C6 and U87 MB cell lines, but caspase dependent for the 13-06 MB and CNS-1 cell lines. In addition, prenylated chalcone treatment (30 μg/ml) resulted in the inhibition of glioma cell migration after 24 and 36 h treatment. Discussion and conclusion: Because prenylated chalcone-induced apoptosis inhibited the proliferation and reduced the invasiveness of glioma cells, the prenylated chalcone has potential as a new chemotherapeutic reagent in the treatment of malignant gliomas. The ultimate goal was to develop a novel potential multi-therapy for treating gliomas.

Peripheral 5-HT7 receptors as a new target for prevention of lung injury and mortality in septic rats

Sepsis is a complex pathophysiological event involving metabolic acidosis, systemic inflammatory response syndrome, tissue damage and multiple organ dysfunction syndrome. Although many new mechanisms are being investigated to enlighten the pathophysiology of sepsis, there is no effective treatment protocol yet. Presence of 5-HT7 receptors in immune tissues prompted us to hypothesize that these receptors have roles in inflammation and sepsis. We investigated the effects of 5-HT7 receptor agonists and antagonists on serum cytokine levels, lung oxidative stress, lung histopathology, nuclear factor κB (NF-κB) positivity and lung 5-HT7 receptor density in cecal ligation and puncture (CLP) induced sepsis model of rats. Agonist administration to septic rats increased survival time; decreased serum cytokine response against CLP; decreased oxidative stress and increased antioxidant system in lungs; decreased the tissue NF-κB immunopositivity, which is high in septic rats; and decreased the sepsis-induced lung injury. In septic rats, as a result of high inflammatory response, 5-HT7 receptor expression in lungs increased significantly and agonist administration, which decreased inflammatory response and related mortality, decreased the 5-HT7 receptor expression. In conclusion, all these data suggest that stimulation of 5-HT7 receptors may be a new therapeutic target for prevention of impaired inflammatory response related lung injury and mortality.

Mechanisms of acute respiratory distress syndrome in children and adults: a review and suggestions for future research

OBJECTIVES

To provide a current overview of the epidemiology and pathophysiology of acute respiratory distress syndrome in adults and children, and to identify research questions that will address the differences between adults and children with acute respiratory distress syndrome.

DATA SOURCES

Narrative literature review and author-generated data.

DATA SELECTION

The epidemiology of acute respiratory distress syndrome in adults and children, lung morphogenesis, and postnatal lung growth and development are reviewed. The pathophysiology of acute respiratory distress syndrome is divided into eight categories: alveolar fluid transport, surfactant, innate immunity, apoptosis, coagulation, direct alveolar epithelial injury by bacterial products, ventilator-associated lung injury, and repair.

DATA EXTRACTION AND SYNTHESIS

Epidemiologic data suggest significant differences in the prevalence and mortality of acute respiratory distress syndrome between children and adults. Postnatal lung development continues through attainment of adult height, and there is overlap between the regulation of postnatal lung development and inflammatory, apoptotic, alveolar fluid clearance, and repair mechanisms. Therefore, there is a different biological baseline network of gene and protein expression in children as compared with adults.

CONCLUSIONS

There are significant obstacles to performing research on children with acute respiratory distress syndrome. However, epidemiologic, clinical, and animal studies suggest age-dependent differences in the pathophysiology of acute respiratory distress syndrome. In order to reduce the prevalence and improve the outcome of patients with acute respiratory distress syndrome, translational studies of inflammatory, apoptotic, alveolar fluid clearance, and repair mechanisms are needed. Understanding the differences in pathophysiologic mechanisms in acute respiratory distress syndrome between children and adults should facilitate identification of novel therapeutic interventions to prevent or modulate lung injury and improve lung repair.

Zinc-rich inhibitor of apoptosis proteins (IAPs) as regulatory factors in the epithelium of normal and inflamed airways

Integrity of the airway epithelium (AE) is important in the context of inhaled allergens and noxious substances, particularly during asthma-related airway inflammation where there is increased vulnerability of the AE to cell death. Apoptosis involves a number of signaling pathways which activate procaspases leading to cleavage of critical substrates. Understanding the factors which regulate AE caspases is important for development of strategies to minimize AE damage and airway inflammation, and therefore to better control asthma. One such factor is the essential dietary metal zinc. Zinc deficiency results in enhanced AE apoptosis, and worsened airway inflammation. This has implications for asthma, where abnormalities in zinc homeostasis have been observed. Zinc is thought to suppress the steps involved in caspase-3 activation. One target of zinc is the family of inhibitor of apoptosis proteins (IAPs) which are endogenous regulators of caspases. More studies are needed to identify the roles of IAPs in regulating apoptosis in normal and inflamed airways and to study their interaction with labile zinc ions. This new information will provide a framework for future clinical studies aimed at monitoring and management of airway zinc levels as well as minimising airway damage and inflammation in asthma.

Acid-induced acute lung injury in mice is associated with P44/42 and c-Jun N-terminal kinase activation and requires the function of tumor necrosis factor α receptor I

Aspiration of hydrochloric acid (HCl)-containing gastric juice leads to acute lung injury (ALI) and hypoxemic respiratory failure due to an exuberant inflammatory response associated with pulmonary edema from increased vascular and epithelial permeability. The aim of this study was to determine the role and signaling mechanisms of tumor necrosis factor α (TNF-α) in experimental ALI from HCl aspiration using a combination of genetic animal models and pharmacologic inhibition strategies. To this end, HCl was instilled intratracheally to mice, followed by respiratory system elastance measurement, bronchoalveolar lavage, and lung tissue harvesting 24 h after injection. Hydrochloric acid instillation induced an inflammatory response in the lungs of wild-type mice, evidenced as increased bronchoalveolar lavage total cells, neutrophils, and total protein; histologic lung injury score; and respiratory system elastance, whereas TNF-α receptor I mRNA levels were maintained. These alterations could be prevented by pretreatment with etanercept or genetic deletion of the 55-kd TNF-α receptor I, but not by deletion of the TNF-α gene. Hydrochloric acid induced a 6-fold increase in apoptotic, caspase 3-positive cells in lung sections from wild-type mice, which was abrogated in mice lacking TNF-α receptor I. In immunoblotting and immunohistochemistry studies, HCl stimulated signaling via p44/42 and c-Jun N-terminal kinase, which was blocked in TNF-α receptor I knockout mice. In conclusion, ALI induced by HCl requires TNF-α receptor I function and associates with activation of downstream proinflammatory signaling pathways p44/42 and c-Jun N-terminal kinase.

Pulmonary surfactant coating of multi-walled carbon nanotubes (MWCNTs) influences their oxidative and pro-inflammatory potential in vitro

Background

Increasing concern has been expressed regarding the potential adverse health effects that may be associated with human exposure to inhaled multi-walled carbon nanotubes (MWCNTs). Thus it is imperative that an understanding as to the underlying mechanisms and the identification of the key factors involved in adverse effects are gained. In the alveoli, MWCNTs first interact with the pulmonary surfactant. At this interface, proteins and lipids of the pulmonary surfactant bind to MWCNTs, affecting their surface characteristics. Aim of the present study was to investigate if the pre-coating of MWCNTs with pulmonary surfactant has an influence on potential adverse effects, upon both (i) human monocyte derived macrophages (MDM) monocultures, and (ii) a sophisticated in vitro model of the human epithelial airway barrier. Both in vitro systems were exposed to MWCNTs either pre-coated with a porcine pulmonary surfactant (Curosurf) or not. The effect of MWCNTs surface charge was also investigated in terms of amino (−NH₂) and carboxyl (−COOH) surface modifications.

Results

Pre-coating of MWCNTs with Curosurf affects their oxidative potential by increasing the reactive oxygen species levels and decreasing intracellular glutathione depletion in MDM as well as decreases the release of Tumour necrosis factor alpha (TNF-α). In addition, an induction of apoptosis was observed after exposure to Curosurf pre-coated MWCNTs. In triple cell-co cultures the release of Interleukin-8 (IL-8) was increased after exposure to Curosurf pre-coated MWCNTs. Effects of the MWCNTs functionalizations were minor in both MDM and triple cell co-cultures.

Conclusions

The present study clearly indicates that the pre-coating of MWCNTs with pulmonary surfactant more than the functionalization of the tubes is a key factor in determining their ability to cause oxidative stress, cytokine/chemokine release and apoptosis. Thus the coating of nano-objects with pulmonary surfactant should be considered for future lung in vitro risk assessment studies.

Lung ischemia-reperfusion injury: a molecular and clinical view on a complex pathophysiological process

Lung ischemia-reperfusion injury remains one of the major complications after cardiac bypass surgery and lung transplantation. Due to its dual blood supply system and the availability of oxygen from alveolar ventilation, the pathogenetic mechanisms of ischemia-reperfusion injury in the lungs are more complicated than in other organs, where loss of blood flow automatically leads to hypoxia. In this review, an extensive overview is given of the molecular and cellular mechanisms that are involved in the pathogenesis of lung ischemia-reperfusion injury and the possible therapeutic strategies to reduce or prevent it. In addition, the roles of neutrophils, alveolar macrophages, cytokines, and chemokines, as well as the alterations in the cell-death related pathways, are described in detail.

Computational modeling with forward and reverse engineering links signaling network and genomic regulatory responses: NF-kappaB signaling-induced gene expression responses in inflammation

Background

Signal transduction is the major mechanism through which cells transmit external stimuli to evoke intracellular biochemical responses. Diverse cellular stimuli create a wide variety of transcription factor activities through signal transduction pathways, resulting in different gene expression patterns. Understanding the relationship between external stimuli and the corresponding cellular responses, as well as the subsequent effects on downstream genes, is a major challenge in systems biology. Thus, a systematic approach is needed to integrate experimental data and theoretical hypotheses to identify the physiological consequences of environmental stimuli.

Results

We proposed a systematic approach that combines forward and reverse engineering to link the signal transduction cascade with the gene responses. To demonstrate the feasibility of our strategy, we focused on linking the NF-κB signaling pathway with the inflammatory gene regulatory responses because NF-κB has long been recognized to play a crucial role in inflammation. We first utilized forward engineering (Hybrid Functional Petri Nets) to construct the NF-κB signaling pathway and reverse engineering (Network Components Analysis) to build a gene regulatory network (GRN). Then, we demonstrated that the corresponding IKK profiles can be identified in the GRN and are consistent with the experimental validation of the IKK kinase assay. We found that the time-lapse gene expression of several cytokines and chemokines (TNF-α, IL-1, IL-6, CXCL1, CXCL2 and CCL3) is concordant with the NF-κB activity profile, and these genes have stronger influence strength within the GRN. Such regulatory effects have highlighted the crucial roles of NF-κB signaling in the acute inflammatory response and enhance our understanding of the systemic inflammatory response syndrome.

Conclusion

We successfully identified and distinguished the corresponding signaling profiles among three microarray datasets with different stimuli strengths. In our model, the crucial genes of the NF-κB regulatory network were also identified to reflect the biological consequences of inflammation. With the experimental validation, our strategy is thus an effective solution to decipher cross-talk effects when attempting to integrate new kinetic parameters from other signal transduction pathways. The strategy also provides new insight for systems biology modeling to link any signal transduction pathways with the responses of downstream genes of interest.

Trace amounts of copper exacerbate beta amyloid-induced neurotoxicity in the cholesterol-fed mice through TNF-mediated inflammatory pathway

Evidence has been gathered to suggest that trace amounts of copper induce neurotoxicity by interaction with elevated cholesterol in diet. Step-through task and Morris water maze task were used to evaluate cognitive function in the animals. Although a 16-week copper treatment alone in mice showed no significant change in learning and memory performances, cholesterol treatment significantly induced learning and memory impairments, which could be exacerbated by the co-treatment with copper. Immunohistochemical studies revealed that trace amounts of copper further stimulated the amyloid precursor protein (APP) upregulation and contributed to amyloid beta-peptide (Abeta) deposition in the brain of cholesterol-fed mice. Western blot analysis showed that copper also increased the protein expression levels of tumor necrosis factor-alpha (TNF-alpha) and the degradation of IkappaB proteins in the brain of cholesterol-fed mice. Furthermore, increased production of high inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expressions were detected in the hippocampus and cerebral cortex of copper and cholesterol co-treated mice by immunohistochemical analysis. These findings suggest that trace amounts of copper could induce APP upregulation, activate inflammatory pathway and exacerbate neurotoxicity in cholesterol-fed mice.

Inhibition of DNA methyltransferase activates tumor necrosis factor alpha-induced monocytic differentiation in acute myeloid leukemia cells

Transcriptional silencing via promoter methylation of genes important for cell growth and differentiation plays a key role in myeloid leukemogenesis. We find that clinically achievable levels of 5-aza-2'-deoxycytidine (5-AZA-dC), a potent inhibitor of DNA methylation, can modify chromatin and restore the ability of tumor necrosis factor alpha (TNFalpha) to induce monocytic differentiation of the acute myeloid leukemia cells NB4 and U937. Although 5-AZA-dC cannot fully induce differentiation, we show that 5-AZA-dC acts directly on TNFalpha-responsive promoters to facilitate TNFalpha-induced transcriptional pathways leading to differentiation. 5-AZA-dC regulates the expression of Dif-2, a TNFalpha target gene, by deacetylating chromatin domains in a methylation-dependent manner. Chromatin immunoprecipitation analyses of the Dif-2 promoter show histone hyperacetylation and a recruitment of the nuclear factor-kappaB transcription factor in response to 5-AZA-dC. Furthermore, 5-AZA-dC plus TNFalpha enhances the level of phosphorylated RNA Pol II at the Dif-2 promoter via synergistic recruitment of TFIIH. We conclude that nonspecific changes in chromatin can allow a specific transcriptional inducer to overcome blocks in leukemic cell differentiation. Our results support the concept of low doses of 5-AZA-dC acting in combination with other agents to target epigenetic changes that drive malignant growth in leukemic cells. [Cancer Res 2009;69(1):55-64].

Different effect of acute treatment with rosiglitazone on rat myocardial ischemia/reperfusion injury by administration method

The present study was undertaken to examine the effect of rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, using different administration methods, on rat myocardial infarct size induced by 30 min of ischemia followed by 4 h of reperfusion. The infarct size was significantly reduced by the continuous infusion of rosiglitazone (0.5 mg/kg/h) from 30 min before occlusion for 2 h. On the other hand, limitation of the infarct size was shown by a bolus injection of 0.75 mg/kg at 5 min before reperfusion, but not by a bolus injection of 1 mg at 30 min before occlusion. The protective effect of rosiglitazone by the bolus injection before occlusion was obtained when an antioxidant, N-acetylcysteine, was concomitantly administered. The cardioprotection by rosiglitazone was associated with the inhibition of increased myeloperoxidase activity, tumor necrosis factor-alpha content and phosphorylation of inhibitor kappaB in the myocardium. The present study demonstrated that the protective effect of rosiglitazone on myocardial ischemia/reperfusion injury occurred most likely by inhibition of the nuclear factor-kappaB pathway through PPAR-gamma activation. However, acute treatment with rosiglitazone is harmful if its concentration is high during ischemia.

Endothelial cell apoptosis in chronically obstructed and reperfused pulmonary artery

Background

Endothelial dysfunction is a major complication of pulmonary endarterectomy (PTE) that can lead to pulmonary edema and persistent pulmonary hypertension. We hypothesized that endothelial dysfunction is related to increased endothelial-cell (EC) death.

Methods

In piglets, the left pulmonary artery (PA) was ligated to induce lung ischemia then reimplanted into the main PA to reperfuse the lung. Animals sacrificed 5 weeks after ligation (n = 5), 2 days after reperfusion (n = 5), or 5 weeks after reperfusion (n = 5) were compared to a sham-operated group (n = 5). PA vasoreactivity was studied and eNOS assayed. EC apoptosis was assessed by TUNEL in the proximal and distal PA and by caspase-3 activity assay in the proximal PA. Gene expression of pro-apoptotic factors (thrombospondin-1 (Thsp-1) and plasminogen activator inhibitor 1 (PAI-1)) and anti-apoptotic factors vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was investigated by QRT-PCR.

Results

Endothelium-dependent relaxation was altered 5 weeks after ligation (p = 0.04). The alterations were exacerbated 2 days after reperfusion (p = 0.002) but recovered within 5 weeks after reperfusion. EC apoptosis was increased 5 weeks after PA ligation (p = 0.02), increased further within 2 days after reperfusion (p < 0.0001), and returned to normal within 5 weeks after reperfusion. Whereas VEGF and bFGF expressions remained unchanged, TSP and PAI-1 expressions peaked 5 weeks after ligation (p = 0.001) and returned to normal within 2 days after reperfusion.

Conclusion

Chronic lung ischemia induces over-expression of pro-apoptotic factors. Lung reperfusion is followed by a dramatic transient increase in EC death that may explain the development of endothelial dysfunction after PE. Anti-apoptotic agents may hold considerable potential for preventing postoperative complications.

Apoptosis-related gene expression in hamster opisthorchiasis post praziquantel treatment

The aim of this study was to investigate the apoptosis-related gene expression in hamster opisthorchiasis after praziquantel treatment. Hamsters were infected with Opisthorchis viverrini metacercariae then treated with praziquantel. The expression of apoptosis-related genes [i.e., apoptosis gene Bcl-2-associated protein X (BAX), caspase 9, p53, and protein kinase B (PKB)] was detected by real-time reverse transcription polymerase chain reaction. Histopathological analyses of liver tissues were studies by staining the sections with hematoxylin and eosin using light microscopy. Apoptotic assay was used to localize the apoptotic cell death. The results show that BAX, Akt/PKB, p53, and caspase 9 expression level were significantly increased on day 30 post infection and at 6 h post treatment and gradually decreased nearly to the uninfected control and 24 h post treatment, perhaps due to a decrease in inflammatory cells. Apoptotic staining was positive reaction at inflammatory cells and nuclei of epithelial bile ducts. Although using praziquantel has an advantage in killing parasites, our results show the effect of praziquantel treatment from host immune response that induces increased apoptosis-related genes in the short term due to an increase in inflammatory cells surrounding the bile ducts.

Apoptosis-related gene expressions in hamsters re-infected with Opisthorchis viverrini and re-treated with praziquantel

Our objective was to reveal whether host immune response in hamster opisthorchiasis post-praziquantel treatment could induce apoptotic cell death in inflammatory cells. We, therefore, investigated apoptosis-related gene expression in hamsters re-infected with Opisthorchis viverrini (OV) and re-treated with praziquantel. Hamsters were re-infected with OV metacercariae then re-treated with praziquantel. The expression of apoptosis-related genes (i.e. apoptosis gene Bcl-2 associated protein X [BAX], caspase 9, p53 and protein kinase B [PKB]) was detected by real-time reverse transcription-polymerase chain reaction. Histopathological analyses of liver tissues were performed by staining the sections with haematoxylin and eosin using light microscopy. The results show that BAX, Akt/PKB, p53 and caspase 9 expression levels were significantly increased on day 30 post-infection and at 6 h post-treatment and gradually decreased to a level near the uninfected control and at 24 h post-treatment, perhaps because of a decrease in inflammatory cells. Apoptotic cell death was observed at the nuclei of epithelial cells of the bile ducts and of T cells. Our results suggest that repeated infection with OV and re-treatment with praziquantel induces a host immune response that increases inflammatory cells, which in turn leads to increase, apoptosis-related gene expression in the short term post-treatment.

Adrenomedullin ameliorates lipopolysaccharide-induced acute lung injury in rats

Adrenomedullin (AM), an endogenous peptide, has been shown to have a variety of protective effects on the cardiovascular system. However, the effect of AM on acute lung injury remains unknown. Accordingly, we investigated whether AM infusion ameliorates lipopolysaccharide (LPS)-induced acute lung injury in rats. Rats were randomized to receive continuous intravenous infusion of AM (0.1 microg x kg(-1) x min(-1)) or vehicle through a microosmotic pump. The animals were intratracheally injected with either LPS (1 mg/kg) or saline. At 6 and 18 h after intratracheal instillation, we performed histological examination and bronchoalveolar lavage and assessed the lung wet/dry weight ratio as an index of acute lung injury. Then we measured the numbers of total cells and neutrophils and the levels of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid (BALF). In addition, we evaluated BALF total protein and albumin levels as indexes of lung permeability. LPS instillation caused severe acute lung injury, as indicated by the histological findings and the lung wet/dry weight ratio. However, AM infusion attenuated these LPS-induced abnormalities. AM decreased the numbers of total cells and neutrophils and the levels of TNF-alpha and CINC in BALF. AM also reduced BALF total protein and albumin levels. In addition, AM significantly suppressed apoptosis of alveolar wall cells as indicated by cleaved caspase-3 staining. In conclusion, continuous infusion of AM ameliorated LPS-induced acute lung injury in rats. This beneficial effect of AM on acute lung injury may be mediated by inhibition of inflammation, hyperpermeability, and alveolar wall cell apoptosis.

Peroxisome proliferator-activated receptors ligands and ischemia-reperfusion injury

Peroxisome proliferator-activated receptors (PPARs) belong to a subfamily of transcription nuclear factors. Three isoforms of PPARs have been identified: alpha, beta/delta and gamma, encoded by different genes and distributed in various tissues. They play important roles in metabolic processes like regulation of glucose and lipid redistribution. They also have anti-atherogenic, anti-inflammatory as well as antihypertensive functions. There is good evidence that ligands of PPARs reduce tissue injury associated with ischemia and reperfusion. The potential utility of PPAR ligands in ischemia and reperfusion will be discussed in this review.

Signal transduction pathways of tumor necrosis factor--mediated lung injury induced by ozone in mice

RATIONALE

Increasing evidence suggests that tumor necrosis factor (TNF)-alpha plays a key role in pulmonary injury caused by environmental ozone (O(3)) in animal models and human subjects. We previously determined that mice genetically deficient in TNF response are protected from lung inflammation and epithelial injury after O(3) exposure.

OBJECTIVES

The present study was designed to determine the molecular mechanisms of TNF receptor (TNF-R)-mediated lung injury induced by O(3).

METHODS

TNF-R knockout (Tnfr(-/-)) and wild-type (Tnfr(+/+)) mice were exposed to 0.3 ppm O(3) or air (for 6, 24, or 48 h), and lung RNA and proteins were prepared. Mice deficient in p50 nuclear factor (NF)-kappaB (Nfkb1(-/-)) or c-Jun-NH(2) terminal kinase 1 (Jnk1(-/-)) and wild-type controls (Nfkb1(+/+), Jnk1(+/+)) were exposed to O(3) (48 h), and the role of NF-kappaB and mitogen-activated protein kinase (MAPK) as downstream effectors of lung injury was analyzed by bronchoalveolar lavage analyses.

RESULTS

O(3)-induced early activation of TNF-R adaptor complex formation was attenuated in Tnfr(-/-) mice compared with Tnfr(+/+) mice. O(3) significantly activated lung NF-kappaB in Tnfr(+/+) mice before the development of lung injury. Basal and O(3)-induced NF-kappaB activity was suppressed in Tnfr(-/-) mice. Compared with Tnfr(+/+) mice, MAPKs and activator protein (AP)-1 were lower in Tnfr(-/-) mice basally and after O(3). Furthermore, inflammatory cytokines, including macrophage inflammatory protein-2, were differentially expressed in Tnfr(-/-) and Tnfr(+/+) mice after O(3). O(3)-induced lung injury was significantly reduced in Nfkb1(-/-) and Jnk1(-/-) mice relative to respective control animals.

CONCLUSIONS

Results suggest that NF-kappaB and MAPK/AP-1 signaling pathways are essential in TNF-R-mediated pulmonary toxicity induced by O(3).

TGF-beta1 and serum both stimulate contraction but differentially affect apoptosis in 3D collagen gels

Apoptosis of fibroblasts may be key for the removal of cells following repair processes. Contraction of three-dimensional collagen gels is a model of wound healing and remodeling. Here two potent inducers of contraction, TGF-β1 and fetal calf serum (FCS) were evaluated for their effect on fibroblast apoptosis in contracting collagen gels. Human fetal lung fibroblasts were cultured in floating type I collagen gels, exposed to TGF-β1 or FCS, and allowed to contract for 5 days. Apoptosis was evaluated using TUNEL and confirmed by DNA content profiling. Both TGF-β1 and serum significantly augmented collagen gel contraction. TGF-β1 also increased apoptosis assessed by TUNEL positivity and DNA content analysis. In contrast, serum did not affect apoptosis. TGF-β1 induction of apoptosis was associated with augmented expression of Bax, a pro-apoptotic member of the Bax/Bcl-2 family, inhibition of Bcl-2, an anti-apoptotic member of the same family, and inhibition of both cIAP-1 and XIAP, two inhibitors of the caspase cascade. Serum was associated with an increase in cIAP-1 and Bcl-2, anti-apoptotic proteins. Interestingly, serum was also associated with an apparent increase in Bax, a pro-apoptotic protein. Blockade of Smad3 with either siRNA or by using murine fibroblasts deficient in Smad3 resulted in a lack of TGF-β induction of augmented contraction and apoptosis. Contraction induced by different factors, therefore, may be differentially associated with apoptosis, which may be related to the persistence or resolution of the fibroblasts that accumulate following injury.

Combination of retinoic acid and tumor necrosis factor overcomes the maturation block in a variety of retinoic acid-resistant acute promyelocytic leukemia cells

Retinoic acid (RA) overcomes the maturation block in t(15:17) acute promyelocytic leukemia (APL), leading to granulocytic differentiation. Patients receiving RA alone invariably develop RA resistance. RA-resistant cells can serve as useful models for the development of treatments for both APL and other leukemias. Previously, we showed that RA and tumor necrosis factor (TNF) promote monocytic differentiation of the APL cell line NB4 and U937 monoblastic cells. Here, we report that combining TNF with RA leads to maturation of several RA-resistant APL cells along a monocytic pathway, whereas UF-1, a patient-derived RA-resistant cell line, showed characteristics of granulocytic differentiation. We found distinct differences in gene regulation between UF-1 cells and cells showing monocytic differentiation. Although IRF-7 was up-regulated by TNF and RA in all cells tested, expression of c-jun and PU.1 correlated with monocytic differentiation. Furthermore, synergistic induction of PU.1 DNA binding and macrophage colony-stimulating factor receptor (m-CSF-1R) mRNA was observed only in cells differentiating into monocytes. Using neutralizing antibodies against m-CSF-1R or its ligand, we found that inhibiting this pathway strongly reduced CD14 expression in response to RA and TNF, suggesting that this pathway is essential for their synergy in RA-resistant leukemia cells. (Blood. 2004;104:3335-3342)

Tumour necrosis factor-alpha and apoptosis in the rat temporomandibular joint

The purpose of this investigation was to investigate the roles that tumour necrosis factor-alpha (TNF-alpha) and apoptosis play during acute inflammation of the temporomandibular joint (TMJ). Adult male Sprague-Dawley rats were injected with complete Freund's adjuvant (CFA) into the TMJ or kept as uninjected controls. The TMJ tissues were removed 2 days post-injection to mimic conditions of acute inflammation and analysed for changes in expression of TNF-alpha, the receptor TNF-R1, caspase-3 and -8, and apoptosis. Concentrations of TNF-alpha, TNF-R1, caspase-3 and -8, and apoptosis were significantly elevated in CFA-injected animals compared to uninjected controls. Tissue incubation with TNF-alpha caused a significant increase in caspase-3 and -8. Also, levels of apoptosis were significantly increased during inflammation, which could be inhibited by the addition of either anti-TNF-alpha neutralising antibody or caspase inhibitors. TNF-alpha may play a significant role in the onset of acute CFA-induced TMJ inflammation, and activation of apoptosis signalling pathways may be involved.

Synergy between all-trans retinoic acid and tumor necrosis factor pathways in acute leukemia cells

The nuclear receptor ligand all-trans retinoic acid (ATRA) causes dramatic terminal differentiation of acute promyelocytic leukemia (APL) cells in vitro and in patients, but it is less active in other malignancies. However, downstream mediators of the effects of ATRA are not well understood. We used a cDNA microarray to search for ATRA-regulated genes in the APL cell line NB4 and found that ATRA regulated several members of the tumor necrosis factor (TNF) pathway. Here we show that TNF can synergize with ATRA to induce differentiation, showing monocytic characteristics more typical of differentiation mediated by TNF than by ATRA. ATRA and TNF can also induce differentiation of the non-APL cell line U937. Underlying this response was an increase in TNF-induced nuclear factor-kappaB (NF-kappaB) DNA binding within 2 hours in the presence of ATRA and activation of NF-kappaB DNA binding and transcriptional activity in response to ATRA alone within 48 hours of ATRA treatment. Furthermore, we found a synergistic induction of the NF-kappaB target genes BCL-3, Dif-2, and TNF receptor 2 (TNFR2) in response to the combination of TNF and ATRA. These genes have been previously shown to play a role in TNF signaling, and amplification of such genes may represent a mechanism whereby TNF and ATRA can act synergistically. We propose that ATRA can prime cancer cells for differentiation triggered by TNF and suggest that targeting the TNF pathway in combination with ATRA may represent a novel route to treat leukemias.

The role of apoptosis in acute lung injury

OBJECTIVE

To discuss current aspects of our understanding of the role of apoptosis in lung injury.

DATA SOURCES

Review of English language literature.

DATA SUMMARY

Apoptosis is a process that produces timely death in senescent cells. Apoptosis is important in developmental biology and in remodeling of tissues during repair. Many apoptosis pathways converge in intracellular protease cascades that lead to DNA cleavage and cell death. Apoptosis pathways can be triggered by surface receptors, which interact with soluble proteins or membrane-bound proteins, such as Fas ligand. Fas ligand accumulates in soluble form at sites of tissue inflammation and has the potential to initiate apoptosis of leukocytes, epithelial cells, and other parenchymal cells. Dysregulation of apoptosis pathways could contribute to the epithelial injury that is characteristic of acute lung injury in humans. The effects of Fas ligand are modulated by factors in lung fluids, such as cytokines (e.g., transforming growth factor-beta, surfactant protein A, and angiotensin II) and a specific Fas ligand decoy receptor (DcR3).

CONCLUSION

Strategies to block apoptosis pathways could be useful in limiting some forms of acute lung injury in humans.

Glycine ameliorates lung reperfusion injury after cold preservation in an ex vivo rat lung model

BACKGROUND

The role of glycine has not been investigated in lung ischemia-reperfusion injury after cold preservation. Furthermore, the role of apoptosis after reperfusion following cold preservation has not been fully understood.

METHODS

Lewis rats were divided into three groups (n=6 each). In the GLY(-) and GLY(+) groups, isolated lungs were preserved for 15 hr at 4 degrees C after a pulmonary artery (PA) flush using our previously developed preservation solution (ET-K; extracellular-type trehalose containing Kyoto), with or without the addition of glycine (5 mM). In the Fresh group, isolated lungs were reperfused immediately after a PA flush with ET-K. They were reperfused for 60 min with an ex vivo perfusion model. Pulmonary function, oxidative stress, apoptosis, and tumor necrosis factor (TNF)-alpha expression were assessed after reperfusion.

RESULTS

Shunt fraction and peak inspiratory pressure after reperfusion in the GLY(-) group were significantly higher than those in the GLY(+) and Fresh groups. Oxidative damage and apoptosis in the alveolar epithelial cells of the GLY(-) group, assessed by immunohistochemical staining and quantification of 8-hydroxy-2'-deoxyguanosine and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling method, were significantly higher than those of the GLY(+) and Fresh groups. There were correlations among shunt fraction, oxidative damage, and apoptosis. There was no expression of TNF-alpha messenger RNA in all groups evaluated by the reverse transcription-polymerase chain reaction.

CONCLUSIONS

Glycine attenuates ischemia/reperfusion injury after cold preservation by reducing oxidative damage and suppressing apoptosis independent of TNF-alpha in this model. The suppression of apoptosis might ameliorate lung function after reperfusion.

Ischemia-reperfusion-induced lung injury

Ischemia-reperfusion-induced lung injury is characterized by nonspecific alveolar damage, lung edema, and hypoxemia occurring within 72 hours after lung transplantation. The most severe form may lead to primary graft failure and remains a significant cause of morbidity and mortality after lung transplantation. Over the past decade, better understanding of the mechanisms of ischemia-reperfusion injury, improvements in the technique of lung preservation, and the development of a new preservation solution specifically for the lung have been associated with a reduction in the incidence of primary graft failure from approximately 30 to 15% or less. Several strategies have also been introduced into clinical practice for the prevention and treatment of ischemia-reperfusion-induced lung injury with various degrees of success. However, only three randomized, double-blinded, placebo-controlled trials on ischemia-reperfusion-induced lung injury have been reported in the literature. In the future, the development of new agents and their application in prospective clinical trials are to be expected to prevent the occurrence of this potentially devastating complication and to further improve the success of lung transplantation.

TNF-dependent BALB/c murine macrophage apoptosis following Mycobacterium tuberculosis infection inhibits bacillary growth in an IFN-gamma independent manner

SETTING

In vitro model of murine macrophage M. tuberculosis infection.

OBJECTIVE

To evaluate the association and cytokine control of host cell apoptosis and bacillary killing in M. tuberculosis -infected murine peritoneal macrophage (PM).

DESIGN

Murine PM from different strains of mice were infected with H37Ra. Bacillary growth and macrophage apoptosis were evaluated under different cytokine conditions.

RESULTS

Like human alveolar macrophages, PM from BALB/c mice were found to undergo apoptosis after infection with M. tuberculosis in a TNF-dependent manner. Neutralizing TNF with anti-TNF antibody inhibited PM apoptosis following infection, and resulted in increased bacillary growth. Pre-treatment of PM with interferon (IFN-gamma) resulted in significant killing of the infecting bacilli, which was not dependent on TNF or apoptosis of the cells. In contrast to BALB/c mice, PM from C3H/HeJ mice did not undergo apoptosis following infection and did not undergo TNF- and apoptosis-dependent inhibition of bacillary growth.

CONCLUSION

These findings suggest that TNF contributes to macrophage inhibition of M. tuberculosis growth by a mechanism that is dependent on apoptosis and independent of IFN-gamma activity. This protective phenotype was not seen in all strains of mice and merits investigation as a marker of mycobacterial host susceptibility.