Interactions between PBEF and oxidative stress proteins--a potential new mechanism underlying PBEF in the pathogenesis of acute lung injury

Single-cell landscape of immunological responses in elderly patients with sepsis

Sepsis is a dysregulated host response to severe infections, and immune dysfunction plays a crucial role in its pathogenesis. Elderly patients, a special population influenced by immunosenescence, are more susceptible to sepsis and have a worse prognosis. However, the immunopathogenic mechanisms underlying sepsis in elderly patients remain unclear. Here, we performed single-cell RNA sequencing of peripheral blood samples from young and old subjects and patients with sepsis. By exploring the transcriptional profiles of immune cells, we analyzed immune cell compositions, phenotype shifts, expression heterogeneities, and intercellular communication. In elderly patients with sepsis, innate immune cells (e.g., monocytes and DCs) exhibit decreased antigen presentation, presenting an overactive inflammatory and senescent phenotype. However, the immunophenotype of T cells shifted to characterize effector, memory, and exhaustion. Moreover, we identified strong interferon-γ responses of T cells in both aging and sepsis groups and a deranged inflammaging status in elderly sepsis patients. Tregs in elderly patients with sepsis showed increased abundance and enhanced immunosuppressive effects. In addition, metabolism-associated pathways were upregulated in T cells in elderly patients with sepsis, and the lysine metabolism pathway was enriched in Tregs. Cell-cell interaction analysis showed that the expression profile of ligand-receptor pairs was probably associated with aggravated immune dysfunction in elderly patients with sepsis. A novel HLA-KIR interaction was observed between Tregs and CD8 + T cells. These findings illustrate the immunological hallmarks of sepsis in elderly patients, and highlight that immunosuppressive and metabolic regulatory pathways may undergo important alterations in elderly patients with sepsis.

IFITM3-mediated activation of TRAF6/MAPK/AP-1 pathways induces acquired TKI resistance in clear cell renal cell carcinoma

PURPOSE

Vascular endothelial growth factor tyrosine kinase inhibitors (TKIs) have been the standard of care for advanced and metastatic clear cell renal cell carcinoma (ccRCC). However, the therapeutic effect of TKI monotherapy remains unsatisfactory given the high rates of acquired resistance to TKI therapy despite favorable initial tumor response.

MATERIALS AND METHODS

To define the TKI-resistance mechanism and identify new therapeutic target for TKI-resistant ccRCC, an integrative differential gene expression analysis was performed using acquired resistant cohort and a public dataset. Sunitinib-resistant RCC cell lines were established and used to test their malignant behaviors of TKI resistance through in vitro and in vivo studies. Immunohistochemistry was conducted to compare expression between the tumor and normal kidney and verify expression of pathway-related proteins.

RESULTS

Integrated differential gene expression analysis revealed increased interferon-induced transmembrane protein 3 (IFITM3) expression in post-TKI samples. IFITM3 expression was increased in ccRCC compared with the normal kidney. TKI-resistant RCC cells showed high expression of IFITM3 compared with TKI-sensitive cells and displayed aggressive biologic features such as higher proliferative ability, clonogenic survival, migration, and invasion while being treated with sunitinib. These aggressive features were suppressed by the inhibition of IFITM3 expression and promoted by IFITM3 overexpression, and these findings were confirmed in a xenograft model. IFITM3-mediated TKI resistance was associated with the activation of TRAF6 and MAPK/AP-1 pathways.

CONCLUSIONS

These results demonstrate IFITM3-mediated activation of the TRAF6/MAPK/AP-1 pathways as a mechanism of acquired TKI resistance, and suggest IFITM3 as a new target for TKI-resistant ccRCC.

Exploration of potential mechanism of interleukin-33 up-regulation caused by 1,4-naphthoquinone black carbon in RAW264.7 cells

BACKGROUND

As air pollution has been paid more attention to by public in recent years, effects and mechanism in particulate matter-triggered health problems become a focus of research. Lysosomes and mitochondria play an important role in regulation of inflammation. Interleukin-33 (IL-33) has been proved to promote inflammation in our previous studies. In this research, macrophage cell line RAW264.7 was used to explore the potential mechanism of upregulation of IL-33 induced by 1,4-naphthoquinone black carbon (1,4-NQ-BC), and to explore changes of lysosomes and mitochondria during the process.

RESULTS

50 μg/mL 1,4-NQ-BC exposure for 24 h dramatically increased expression of IL-33 in RAW264.7 cells. Lysosomal membrane permeability was damaged by 1,4-NQ-BC treatment, and higher mitochondrial membrane potential and ROS level were induced by 1,4-NQ-BC. The results of proteomics suggested that expression of ferritin light chain was increased after cells were challenged with 1,4-NQ-BC, and it was verified by Western blot. Meanwhile, expressions of p62 and LC3B-II were increased by 50 μg/mL 1,4-NQ-BC in RAW264.7 cells. Ultimately, expression of IL-33 could return to same level as control in cells treated with 50 μg/mL 1,4-NQ-BC and 50 μM deferoxamine combined.

CONCLUSIONS

1,4-NQ-BC induces IL-33 upregulation in RAW264.7 cells, and it is responsible for higher lysosomal membrane permeability and ROS level, lower mitochondrial membrane potential, and inhibition of autophagy. Ferritin light chain possibly plays an important role in the upregulation of IL-33 evoked by 1,4-NQ-BC.

Integrative overview of IFITMs family based on Bioinformatics analysis

Human interferon-induced transmembrane proteins (IFITMs) family is a multi-functional biomacromolecule family playing a critical role in various physiological processes, such as, antiviral immunity, tumor suppression, and bone formation. Although there are many studies proving that a subset of tumors strongly links to the changes of IFITMs, the link between different IFITMs mutant types and diverse tumors has not been studied thoroughly. To investigate the law of expression among IFITMs internal members and the linking of IFITMs mutant types and cancers, online databases were used to pool together relevant data for bioinformatics analysis. Here, we summarize mutations, expression, and functions of human IFITMs, analyze diverse expression levels of IFITMs in physiological and pathological tissues, predict protein-protein interaction (PPI) networks, and target miRNAs and relevant signaling pathways of IFITMs. The results show that IFITM1, IFITM2, and IFITM3 have similar motif pattern constructions and physiological functions, while IFITM5 and IFITM10 show far diversity from them. Particularly, IFITM1-3, in conjunction with interacting proteins, is strongly related to development and overall survival rates of a portion of cancers, including renal cancer and uveal melanoma (UVM). This trait may make IFITM1-3 become a prognostic marker of cancers. Meanwhile, hsa_circ_0116375 has been found as the common circRNA for IFITM2, IFITM3, IFITM5, and IFITM10.

Can adipokine visfatin be a novel marker of pregnancy-related disorders in women with obesity?

Overweight and obesity have become a dangerous disease requiring multiple interventions, treatment and preventions. In women of reproductive age, obesity is one of the most common medical conditions. Among others, obese state is characterized by low-grade systemic inflammation and enhanced oxidative stress. Increased maternal body mass index might amplify inflammation and reactive oxygen species production, which is associated with unfavourable clinical outcomes that affect both mother and child. Intrauterine growth retardation, preeclampsia, or gestational diabetes mellitus are examples of the hampered maternal and foetoplacental unit interactions. Visfatin is the obesity-related adipokine produced mainly by the visceral adipose tissue. Visfatin affects glucose homeostasis, as well as the regulation of genes related to oxidative stress and inflammatory response. Here, we review visfatin interactions in pregnancy-related disorders linked to obesity. We highlight the possible predictive and prognostic value of visfatin in diagnostic strategies on gravidas with obesity.

Nicotinamide phosphoribosyltransferase purification using SUMO expression system

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme in the salvage pathway required for nicotinamide adenine dinucleotide synthesis. The secreted NAMPT protein serves as a master regulatory cytokine involved in activation of evolutionarily conserved inflammatory networks. Appreciation of the role of NAMPT as a damage-associated molecular pattern protein (DAMP) has linked its activities to several disorders via Toll-like receptor 4 (TLR4) binding and inflammatory cascade activation. Information is currently lacking concerning the precise mode of the NAMPT protein functionality due to limited availability of purified protein for use in in vitro and in vivo studies. Here we report successful NAMPT expression using the pET-SUMO expression vector in E. coli strain SHuffle containing a hexa-His tag for purification. The Ulp1 protease was used to cleave the SUMO and hexa-His tags, and the protein was purified by immobilized-metal affinity chromatography. The protein yield was ~4 mg/L and initial biophysical characterization of the protein using circular dichroism revealed the secondary structural elements, while dynamic light scattering demonstrated the presence of oligomeric units. The NAMPT-SUMO showed a predominantly dimeric protein with functional enzymatic activity. Finally, we report NAMPT solubilization in n-dodecyl-β-d-maltopyranoside (DDM) detergent in monomeric form, thus enhancing the opportunity for further structural and functional investigations.

Genomic and Genetic Approaches to Deciphering Acute Respiratory Distress Syndrome Risk and Mortality

Significance: Acute respiratory distress syndrome (ARDS) is a severe, highly heterogeneous critical illness with staggering mortality that is influenced by environmental factors, such as mechanical ventilation, and genetic factors. Significant unmet needs in ARDS are addressing the paucity of validated predictive biomarkers for ARDS risk and susceptibility that hamper the conduct of successful clinical trials in ARDS and the complete absence of novel disease-modifying therapeutic strategies. Recent Advances: The current ARDS definition relies on clinical characteristics that fail to capture the diversity of disease pathology, severity, and mortality risk. We undertook a comprehensive survey of the available ARDS literature to identify genes and genetic variants (candidate gene and limited genome-wide association study approaches) implicated in susceptibility to developing ARDS in hopes of uncovering novel biomarkers for ARDS risk and mortality and potentially novel therapeutic targets in ARDS. We further attempted to address the well-known health disparities that exist in susceptibility to and mortality from ARDS. Critical Issues: Bioinformatic analyses identified 201 ARDS candidate genes with pathway analysis indicating a strong predominance in key evolutionarily conserved inflammatory pathways, including reactive oxygen species, innate immunity-related inflammation, and endothelial vascular signaling pathways. Future Directions: Future studies employing a system biology approach that combines clinical characteristics, genomics, transcriptomics, and proteomics may allow for a better definition of biologically relevant pathways and genotype-phenotype connections and result in improved strategies for the sub-phenotyping of diverse ARDS patients via molecular signatures. These efforts should facilitate the potential for successful clinical trials in ARDS and yield a better fundamental understanding of ARDS pathobiology.

Novel Mechanism for Nicotinamide Phosphoribosyltransferase Inhibition of TNF-α-mediated Apoptosis in Human Lung Endothelial Cells

Nicotinamide phosphoribosyltransferase (NAMPT) exists as both intracellular NAMPT and extracellular NAMPT (eNAMPT) proteins. eNAMPT is secreted into the blood and functions as a cytokine/enzyme (cytozyme) that activates NF-κB signaling via ligation of Toll-like receptor 4 (TLR4), further serving as a biomarker for inflammatory lung disorders such as acute respiratory distress syndrome. In contrast, intracellular NAMPT is involved in nicotinamide mononucleotide synthesis and has been implicated in the regulation of cellular apoptosis, although the exact mechanisms for this regulation are poorly understood. We examined the role of NAMPT in TNF-α-induced human lung endothelial cell (EC) apoptosis and demonstrated that reduced NAMPT expression (siRNA) increases EC susceptibility to TNF-α-induced apoptosis as reflected by PARP-1 cleavage and caspase-3 activation. In contrast, overexpression of NAMPT served to reduce degrees of TNF-α-induced EC apoptosis. Inhibition of nicotinamide mononucleotide synthesis by FK866 (a selective NAMPT enzymatic inhibitor) failed to alter TNF-α-induced human lung EC apoptosis, suggesting that NAMPT-dependent NAD⁺ generation is unlikely to be involved in regulation of TNF-α-induced EC apoptosis. We next confirmed that TNF-α-induced EC apoptosis is attributable to NAMPT secretion into the EC culture media and subsequent eNAMPT ligation of TLR4 on the EC membrane surface. Silencing of NAMPT expression, direct neutralization of secreted eNAMPT by an NAMPT-specific polyclonal antibody (preventing TLR4 ligation), or direct TLR4 antagonism all served to significantly increase EC susceptibility to TNF-α-induced EC apoptosis. Together, these studies provide novel insights into NAMPT contributions to lung inflammatory events and to novel mechanisms of EC apoptosis regulation.

Role of peroxisome proliferator-activated receptor-gamma activation on visfatin, advanced glycation end products, and renal oxidative stress in obesity-induced type 2 diabetes mellitus

The present study focused on the role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation on renal oxidative damages, serum visfatin, and advanced glycation end products (AGEs) in high-fat diet (HFD)-induced type 2 diabetes mellitus. Following the institutional animal ethics committee guidelines, Wistar rats were categorized into five groups: group 1: fed on a normal rat diet; group 2: HFD-induced obese rats (HFD for 8 weeks); group 3: HFD-fed rats treated with rosiglitazone (RSG; 3 mg/kg orally for 7 days); group 4: T2DM rats induced by HFD and low dose of streptozotocin (i.p. 35 mg/kg); group 5: T2DM rats treated with RSG (3 mg/kg orally for 7 days). Serum levels of AGEs and visfatin, renal damage, and oxidative stress were analyzed. Results showed that HFD-induced obesity and T2DM caused an elevated blood glucose, serum AGEs, visfatin, insulin, urea, creatinine, and tissue malondialdehyde, whereas a decreased catalase and superoxide dismutase activity were observed. The PPAR-γ activation via agonist restored these changes. Our findings suggest that AGEs and visfatin possess an important role in the progression of renal oxidative stress, which can be reduced by the PPAR-γ agonist that impede deleterious effects of HFD and HFD-induced T2DM on renal damage.

Extracellular nicotinamide phosphoribosyltransferase, a new cancer metabokine

In this review, we focus on the secreted form of nicotinamide phosphoribosyltransferase (NAMPT); extracellular NAMPT (eNAMPT), also known as pre-B cell colony-enhancing factor or visfatin. Although intracellular NAMPT is a key enzyme in controlling NAD metabolism, eNAMPT has been reported to function as a cytokine, with many roles in physiology and pathology. Circulating eNAMPT has been associated with several metabolic and inflammatory disorders, including cancer. Because cytokines produced in the tumour micro-environment play an important role in cancer pathogenesis, in part by reprogramming cellular metabolism, future improvements in cancer immunotherapy will require a better understanding of the crosstalk between cytokine action and tumour biology. In this review, the knowledge of eNAMPT in cancer will be discussed, focusing on its immunometabolic function as a metabokine, its secretion, its mechanism of action and possible roles in the cancer micro-environment.

Analysis of the nicotinamide phosphoribosyltransferase family provides insight into vertebrate adaptation to different oxygen levels during the water-to-land transition

One of the most important events in vertebrate evolutionary history is the water-to-land transition, during which some morphological and physiological changes occurred in concert with the loss of specific genes in tetrapods. However, the molecular mechanisms underlying this transition have not been well explored. To explore vertebrate adaptation to different oxygen levels during the water-to-land transition, we performed comprehensive bioinformatics and experimental analysis aiming to investigate the NAMPT family in vertebrates. NAMPT, a rate-limiting enzyme in the salvage pathway of NAD+ biosynthesis, is critical for cell survival in a hypoxic environment, and a high level of NAMPT significantly augments oxidative stress in normoxic environments. Phylogenetic analysis showed that NAMPT duplicates arose from a second round whole-genome duplication event. NAMPTA existed in all classes of vertebrates, whereas NAMPTB was only found in fishes and not tetrapods. Asymmetric evolutionary rates and purifying selection were the main evolutionary forces involved. Although functional analysis identified several functionally divergent sites during NAMPT family evolution, in vitro experimental data demonstrated that NAMPTA and NAMPTB were functionally conserved for NAMPT enzymatic function in the NAD+ salvage pathway. In situ hybridization revealed broad NAMPTA and NAMPTB expression patterns, implying regulatory functions over a wide range of developmental processes. The morpholino-mediated knockdown data demonstrated that NAMPTA was more essential than NAMPTB for vertebrate embryo development. We propose that the retention of NAMPTB in water-breathing fishes and its loss in air-breathing tetrapods resulted from vertebrate adaptation to different oxygen levels during the water-to-land transition.

Nicotinamide exacerbates hypoxemia in ventilator-induced lung injury independent of neutrophil infiltration

Background

Ventilator-induced lung injury is a form of acute lung injury that develops in critically ill patients on mechanical ventilation and has a high degree of mortality. Nicotinamide phosphoribosyltransferase is an enzyme that is highly upregulated in ventilator-induced lung injury and exacerbates the injury when given exogenously. Nicotinamide (vitamin B3) directly inhibits downstream pathways activated by Nicotinamide phosphoribosyltransferase and is protective in other models of acute lung injury.

Methods

We administered nicotinamide i.p. to mice undergoing mechanical ventilation with high tidal volumes to study the effects of nicotinamide on ventilator-induced lung injury. Measures of injury included oxygen saturations and bronchoalveolar lavage neutrophil counts, protein, and cytokine levels. We also measured expression of nicotinamide phosophoribosyltransferase, and its downstream effectors Sirt1 and Cebpa, Cebpb, Cebpe. We assessed the effect of nicotinamide on the production of nitric oxide during ventilator-induced lung injury. We also studied the effects of ventilator-induced lung injury in mice deficient in C/EBPε.

Results

Nicotinamide treatment significantly inhibited neutrophil infiltration into the lungs during ventilator-induced lung injury, but did not affect protein leakage or cytokine production. Surprisingly, mice treated with nicotinamide developed significantly worse hypoxemia during mechanical ventilation. This effect was not linked to increases in nitric oxide production or alterations in expression of Nicotinamide phosphoribosyl transferase, Sirt1, or Cebpa and Cebpb. Cebpe mRNA levels were decreased with either nicotinamide treatment or mechanical ventilation, but mice lacking C/EBPε developed the same degree of hypoxemia and ventilator-induced lung injury as wild-type mice.

Conclusions

Nicotinamide treatment during VILI inhibits neutrophil infiltration of the lungs consistent with a strong anti-inflammatory effect, but paradoxically also leads to the development of significant hypoxemia. These findings suggest that pulmonary neutrophilia is not linked to hypoxemia in ventilator-induced lung injury, and that nicotinamide exacerbates hypoxemia during VILI.

Visfatin induces MUC8 and MUC5B expression via p38 MAPK/ROS/NF-κB in human airway epithelial cells

Background

Among a variety of inflammatory mediators, visfatin is a proinflammatory adipocytokine associated with inflammatory reactions in obesity, metabolic syndrome, chronic inflammatory disease, and autoimmune disease. However, the biological role of visfatin in secretion of major mucins in human airway epithelial cells has not been reported. Therefore, this study was conducted in order to investigate the effect and the brief signaling pathway of visfatin on MUC8 and MUC5B expression in human airway epithelial cells.

Results

Visfatin significantly induced MUC8 and MUC5B expression. Visfatin significantly activated phosphorylation of p38 MAPK. Treatment with SB203580 (p38 MAPK inhibitor) and knockdown of p38 MAPK by siRNA significantly blocked visfatin-induced MUC8 and MUC5B expression.Visfatin significantly increased ROS formation. Treatment with SB203580 significantly attenuated visfatin-induced ROS formation. Treatment with NAC (ROS scavenger) and DPI (NADPH oxidase inhibitor) significantly attenuated visfatin-induced MUC8 and MUC5B expression. However, treatment with NAC and DPI did not attenuate visfatin-activated phosphorylation of p38 MAPK. Visfatin significantly activated the phosphorylation of NF-κB. Treatment with PDTC (NF-κB inhibitor) significantly attenuated visfatin-induced MUC8 and MUC5B expression.

Conclusions

These results suggest that visfatin induces MUC8 and MUC5B expression through p38 MAPK/ROS/NF-κB signaling pathway in human airway epithelial cells.

Pre-B cell colony enhancing factor (PBEF), a cytokine with multiple physiological functions

Pre-B cell colony enhancing factor (PBEF) is regarded as a proinflammatory cytokine. Named for its first discovered function as a pre-B cell colony enhancing factor, it has since been found to have many other functions relating to cell metabolism, inflammation, and immune modulation. It has also been found to have intracellular and extracellular forms, with the two overlapping in function. Most of the intracellular functions of PBEF are due to its role as a nicotinamide phosphoribosyltransferase (Nampt). It has been found in human endothelial cells, where it is able to induce angiogenesis through upregulation of VEGF and VEGFR and secretion of MCP-1. In human umbilical endothelial cells, PBEF increases levels of the protease MMP 2/9. PBEF has also been found in a variety of immune cells other than B cells and has been shown to inhibit apoptosis of macrophages. Extracellular PBEF has been shown to increase inflammatory cytokines, such as TNF-α, IL-1β, IL-16, and TGF-β1, and the chemokine receptor CCR3. PBEF also increases the production of IL-6, TNF-α, and IL-1β in CD14(+) monocyctes, macrophages, and dendritic cells, enhances the effectiveness of T cells, and is vital to the development of both B and T lymphocytes. The purpose of this review is to summarize the recent advances in PBEF research.

Astroglial IFITM3 mediates neuronal impairments following neonatal immune challenge in mice

Interferon-induced transmembrane protein 3 (IFITM3) ıplays a crucial role in the antiviral responses of Type I interferons (IFNs). The role of IFITM3 in the central nervous system (CNS) is, however, largely unknown, despite the fact that its expression is increased in the brains of patients with neurologic and neuropsychiatric diseases. Here, we show the role of IFITM3 in long-lasting neuronal impairments in mice following polyriboinosinic-polyribocytidylic acid (polyI:C, a synthetic double-stranded RNA)-induced immune challenge during the early stages of development. We found that the induction of IFITM3 expression in the brain of mice treated with polyI:C was observed only in astrocytes. Cultured astrocytes were activated by polyI:C treatment, leading to an increase in the mRNA levels of inflammatory cytokines as well as Ifitm3. When cultured neurons were treated with the conditioned medium of polyI:C-treated astrocytes (polyI:C-ACM), neurite development was impaired. These polyI:C-ACM-induced neurodevelopmental abnormalities were alleviated by ifitm3(-/-) astrocyte-conditioned medium. Furthermore, decreases of MAP2 expression, spine density, and dendrite complexity in the frontal cortex as well as memory impairment were evident in polyI:C-treated wild-type mice, but such neuronal impairments were not observed in ifitm3(-) (/) (-) mice. We also found that IFITM3 proteins were localized to the early endosomes of astrocytes following polyI:C treatment and reduced endocytic activity. These findings suggest that the induction of IFITM3 expression in astrocytes by the activation of the innate immune system during the early stages of development has non-cell autonomous effects that affect subsequent neurodevelopment, leading to neuropathological impairments and brain dysfunction, by impairing endocytosis in astrocytes.

Regulation of cell survival and death by pyridine nucleotides

Pyridine nucleotides (PNs), such as NAD(H) and NADP(H), mediate electron transfer in many catabolic and anabolic processes. In general, NAD(+) and NADP(+) receive electrons to become NADH and NADPH by coupling with catabolic processes. These electrons are utilized for biologically essential reactions such as ATP production, anabolism and cellular oxidation-reduction (redox) regulation. Thus, in addition to ATP, NADH and NADPH could be defined as high-energy intermediates and "molecular units of currency" in energy transfer. We discuss the significance of PNs as energy/electron transporters and signal transducers, in regulating cell death and/or survival processes. In the first part of this review, we describe the role of NADH and NADPH as electron donors for NADPH oxidases (Noxs), glutathione (GSH), and thioredoxin (Trx) systems in cellular redox regulation. Noxs produce superoxide/hydrogen peroxide yielding oxidative environment, whereas GSH and Trx systems protect against oxidative stress. We then describe the role of NAD(+) and NADH as signal transducers through NAD(+)-dependent enzymes such as PARP-1 and Sirt1. PARP-1 is activated by damaged DNA in order to repair the DNA, which attenuates energy production through NAD(+) consumption; Sirt1 is activated by an increased NAD(+)/NADH ratio to facilitate signal transduction for metabolic adaption as well as stress responses. We conclude that PNs serve as an important interface for distinct cellular responses, including stress response, energy metabolism, and cell survival/death.

The small interferon-induced transmembrane genes and proteins

Interferon-induced transmembrane (IFITM) genes are transcribed in most tissues and are with the exception of IFITM5 interferon inducible. They are involved in early development, cell adhesion, and control of cell growth. Most IFITM genes are activated in response to bacterial and viral infections, and the exact host immune defense mechanisms are still unknown. Elevated gene expression triggered by past or chronic inflammation could prevent spreading of pathogens by limiting host cell proliferation. Accordingly, induction in cells with low basal protein levels is sufficient to drive growth arrest and a senescence-like morphology. On the other hand, loss of IFITM levels in cancer is correlated with pronounced malignancy; thus, these genes are considered as tumor suppressors. However, several cancer cells have deregulated high levels of IFITM transcripts, indicating a tumor progression stage where at least one of the interferon-controlled antiproliferative pathways has been silenced. Phylogenetic analyses of the protein coding genomic sequences suggest a single interferon-inducible gene in the common ancestor of rodents and primates. Biological functions studied so far may have evolved in parallel, and functional characterization of IFITM proteins will provide insight into innate immune defense, cancer development, and other pathways.

Nitric oxide, oxidative stress and inflammation in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic and progressive disease characterized by a persistent elevation of pulmonary artery pressure accompanied by right ventricular hypertrophy (RVH). The current treatment for pulmonary hypertension is limited and only provides symptomatic relief due to unknown cause and pathogenesis of the disease. Both vasoconstriction and structural remodeling (enhanced proliferation of vascular smooth muscle cell) of the pulmonary arteries contribute to the progressive course of PAH, irrespective of different underlying causes. The exact molecular mechanism of PAH, however, is not fully understood. The purpose of this review is to provide recent advances in the mechanistic investigation of PAH. Specifically, this review focuses on nitric oxide, oxidative stress and inflammation and how these factors contribute to the development and progression of PAH. This review also discusses recent and potential therapeutic advancements for the treatment of PAH.

Visfatin induces oxidative stress in differentiated C2C12 myotubes in an Akt- and MAPK-independent, NFkB-dependent manner

Adipose tissue is an important endocrine and metabolic tissue that is actively involved in cross-talk with peripheral organs such as skeletal muscle. It is likely that adipose-derived factors may underlie the development of insulin resistance in muscle. Thus, the cross-talk between adipose and muscle may be important for the propagation of obesity-related diseases. Visfatin (Pre-B-cell colony-enhancing factor 1 homolog/Nampt) is a recently discovered adipokine with pleiotropic functions. The aim of this study was to examine the effect of visfatin on cellular stress responses and signalling pathways in skeletal muscle. Visfatin treatment of differentiated C2C12 myotubes generated reactive oxygen species (ROS) comprising both superoxide and hydrogen peroxide that was dependent on de novo transcription and translation. In differentiated C2C12 myoblasts, visfatin had no effects on insulin-stimulated Akt phosphorylation nor on activation of the Akt signalling pathway. Additionally, visfatin-induced oxidative stress occurred independent of activation of the stress-activated protein kinases (MAPKs) ERK and p38. In contrast, phosphorylation of NFkB was associated with visfatin-mediated generation of ROS and blockade of this pathway via selective IKK inhibition led to a partial reduction in oxidative stress. Furthermore, the generation of ROS following visfatin treatment was highly dependent on both de novo transcription and translation. Taken together, these findings provide novel insights for the unique pathophysiological role of visfatin in skeletal muscle.