TNF stimulates expression of mouse MHC class I genes by inducing an NF kappa B-like enhancer binding activity which displaces constitutive factors

Modulation of SEMA4D-modified titanium surface on M2 macrophage polarization via activation of Rho/ROCK-mediated lactate release of endothelial cells: In vitro and in vivo

SEMA4D-modified titanium surfaces can indirectly regulate macrophages through endothelial cells to achieve an anti-inflammatory effect, which is beneficial for healing soft tissues around the gingival abutment. However, the mechanism of surface-induced cellular phenotypic changes in SEMA4D-modified titanium has not yet been elucidated. SEMA4D activates the RhoA signaling pathway in endothelial cells, which coordinates metabolism and cytoskeletal remodeling. This study hypothesized that endothelial cells inoculated on SEMA4D-modified titanium surfaces can direct M2 polarization of macrophages via metabolites. An indirect co-culture model of endothelial cells and macrophages was constructed in vitro, and specific inhibitors were employed. Subsequently, endothelial cell adhesion and migration, metabolic changes, Rho/ROCK1 expression, and inflammatory expression of macrophages were assessed via immunofluorescence microscopy, specific kits, qRT-PCR, and Western blotting. Moreover, an in vivo rat bilateral maxillary implant model was constructed to evaluate the soft tissue healing effect. The in vitro experiments showed that the SEMA4D group had stronger endothelial cell adhesion and migration, increased Rho/ROCK1 expression, and enhanced release of lactate. Additionally, decreased macrophage inflammatory expression was observed. In contrast, the inhibitor group partially suppressed lactate metabolism and motility, whereas increased inflammatory expression. The in vivo analyses indicated that the SEMA4D group had faster and better angiogenic and anti-inflammatory effects, especially in the early stage. In conclusion, via the Rho/ROCK1 signaling pathway, the SEMA4D-modified titanium surface promotes endothelial cell adhesion and migration and lactic acid release, then the paracrine lactic acid promotes the polarization of macrophages to M2, thus obtaining the dual effects of angiogenesis and anti-inflammation.

Neuroprotection by upregulation of the major histocompatibility complex class I (MHC I) in SOD1G93A mice

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that progressively affects motoneurons, causing muscle atrophy and evolving to death. Astrocytes inhibit the expression of MHC-I by neurons, contributing to a degenerative outcome. The present study verified the influence of interferon β (IFN β) treatment, a proinflammatory cytokine that upregulates MHC-I expression, in SOD1G93A transgenic mice. For that, 17 days old presymptomatic female mice were subjected to subcutaneous application of IFN β (250, 1,000, and 10,000 IU) every other day for 20 days. Rotarod motor test, clinical score, and body weight assessment were conducted every third day throughout the treatment period. No significant intergroup variations were observed in such parameters during the pre-symptomatic phase. All mice were then euthanized, and the spinal cords collected for comparative analysis of motoneuron survival, reactive gliosis, synapse coverage, microglia morphology classification, cytokine analysis by flow cytometry, and RT-qPCR quantification of gene transcripts. Additionally, mice underwent Rotarod motor assessment, weight monitoring, and neurological scoring. The results show that IFN β treatment led to an increase in the expression of MHC-I, which, even at the lowest dose (250 IU), resulted in a significant increase in neuronal survival in the ALS presymptomatic period which lasted until the onset of the disease. The treatment also influenced synaptic preservation by decreasing excitatory inputs and upregulating the expression of AMPA receptors by astrocytes. Microglial reactivity quantified by the integrated density of pixels did not decrease with treatment but showed a less activated morphology, coupled with polarization to an M1 profile. Disease progression upregulated gene transcripts for pro- and anti-inflammatory cytokines, and IFN β treatment significantly decreased mRNA expression for IL4. Overall, the present results demonstrate that a low dosage of IFN β shows therapeutic potential by increasing MHC-I expression, resulting in neuroprotection and immunomodulation.

Methamphetamine signals transcription of IL1β and TNFα in a reactive oxygen species-dependent manner and interacts with HIV-1 Tat to decrease antioxidant defense mechanisms

Methamphetamine (Meth) abuse is a common HIV co-morbidity that is linked to aggravated Central Nervous System (CNS) inflammation, which accentuates HIV- associated neurological disorders, triggered both directly or indirectly by the drug. We used the well-established human innate immune macrophage cell line system (THP1) to demonstrate that Reactive Oxygen Species (ROS) immediately induced by Meth play a role in the increased transcription of inflammatory genes, in interaction with HIV-1 Tat peptide. Meth and Tat, alone and together, affect early events of transcriptional activity, as indicated by changes in RNA polymerase (RNAPol) recruitment patterns throughout the genome, via ROS-dependent and -independent mechanisms. IL1β (IL1β) and TNF α (TNFα), two genes with defining roles in the inflammatory response, were both activated in a ROS-dependent manner. We found that this effect occurred via the activation of the activator protein 1 (AP-1) comprising cFOS and cJUN transcription factors and regulated by the SRC kinase. HIV-1 Tat, which was also able to induce the production of ROS, did not further impact the effects of ROS in the context of Meth, but promoted gene activity independently from ROS, via additional transcription factors. For instance, HIV-1 Tat increased NFkB activation and activated gene clusters regulated by Tata box binding peptide, ING4 and IRF2. Importantly, HIV-1 Tat decreased the expression of anti-oxidant genes, where its suppression of the detoxifying machinery may contribute to the aggravation of oxidative stress induced by ROS in the context of Meth. Our results provide evidence of effects of Meth via ROS and interactions with HIV Tat that promote the transcription of inflammatory genes such as IL1β and TNFα.

Cellular inhibitor of apoptosis 2 (cIAP2) restricts neuroinflammation during experimental autoimmune encephalomyelitis

Background

Immune activation, neuroinflammation, and cell death are the hallmarks of multiple sclerosis (MS), which is an autoimmune demyelinating disease of the central nervous system (CNS). It is well-documented that the cellular inhibitor of apoptosis 2 (cIAP2) is induced by inflammatory stimuli and regulates adaptive and innate immune responses, cell death, and the production of inflammatory mediators. However, the impact of cIAP2 on neuroinflammation associated with MS and disease severity remains unknown.

Methods

We used experimental autoimmune encephalomyelitis (EAE), a widely used mouse model of MS, to assess the effect of cIAP2 deletion on disease outcomes. We performed a detailed analysis on the histological, cellular, and molecular levels. We generated and examined bone-marrow chimeras to identify the cIAP2-deficient cells that are critical to the disease outcomes.

Results

cIAP2^−/− mice exhibited increased EAE severity, increased CD4⁺ T cell infiltration, enhanced proinflammatory cytokine/chemokine expression, and augmented demyelination. This phenotype was driven by cIAP2-deficient non-hematopoietic cells. cIAP2 protected oligodendrocytes from cell death during EAE by limiting proliferation and activation of brain microglia. This protective role was likely exerted by cIAP2-mediated inhibition of the non-canonical NLRP3/caspase-8-dependent myeloid cell activation during EAE.

Conclusions

Our findings suggest that cIAP2 is needed to modulate neuroinflammation, cell death, and survival during EAE. Significantly, our data demonstrate the critical role of cIAP2 in limiting the activation of microglia during EAE, which could be explored for developing MS therapeutics in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02527-6.

The Epidemiology and Mechanisms of Lifetime Cardiopulmonary Morbidities Associated With Pre-Pregnancy Obesity and Excessive Gestational Weight Gain

Obesity has reached pandemic proportions in the last few decades. The global increase in obesity has contributed to an increase in the number of pregnant women with pre-pregnancy obesity or with excessive gestational weight gain. Obesity during pregnancy is associated with higher incidence of maternal co-morbidities such as gestational diabetes and hypertension. Both obesity during pregnancy and its associated complications are not only associated with immediate adverse outcomes for the mother and their newborns during the perinatal period but, more importantly, are linked with long-term morbidities in the offsprings. Neonates born to women with obesity are at higher risk for cardiac complications including cardiac malformations, and non-structural cardiac issues such as changes in the microvasculature, e.g., elevated systolic blood pressure, and overt systemic hypertension. Pulmonary diseases associated with maternal obesity include respiratory distress syndrome, asthma during childhood and adolescence, and adulthood diseases, such as chronic obstructive pulmonary disease. Sequelae of short-term complications compound long-term outcomes such as long-term obesity, hypertension later in life, and metabolic complications including insulin resistance and dyslipidemia. Multiple mechanisms have been proposed to explain these adverse outcomes and are related to the emerging knowledge of pathophysiology of obesity in adults. The best investigated ones include the role of obesity-mediated metabolic alterations and systemic inflammation. There is emerging evidence linking metabolic and immune derangements to altered biome, and alteration in epigenetics as one of the intermediary mechanisms underlying the adverse outcomes. These are initiated as part of fetal adaptation to obesity during pregnancy which are compounded by rapid weight gain during infancy and early childhood, a known complication of obesity during pregnancy. This newer evidence points toward the role of specific nutrients and changes in biome that may potentially modify the adverse outcomes observed in the offsprings of women with obesity.

Anti-inflammatory effects of the immobilization of SEMA4D on titanium surfaces in an endothelial cell/macrophage indirect coculture model

In this study, we established a procedure to prepare a Semaphorin4D (SEMA4D)-immobilized titanium surface and explored its effects on macrophage behaviors in an endothelial cell/macrophage indirect coculture model. The SEMA4D-bovine serum albumin complex was immobilized onto a preprocessed poly L-lysine titanium surface through NaOH hydrothermal treatment and self-assembly technology. All titanium specimens were examined for surface microstructure, surface element composition, and surface wettability by field emission scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), and water contact angle measurement, respectively. Subsequently, we constructed an endothelial cell/macrophage indirect coculture model and evaluated the activation of NF-κB signaling pathway and the expression of proinflammatory cytokines (TNFα, IL-6, and IL-1β) in macrophages. In XPS analysis, the SEMA4D-immobilized titanium surface appeared as a loose porous structure covered with uniform film, which exhibited better hydrophilicity than the control smooth titanium surface. In the indirect coculture model, SEMA4D attenuated the activation of NF-κB signaling pathway of lipopolysaccharide-stimulated THP-1 macrophages, thereby downregulating the expression of proinflammatory cytokines in macrophages. In conclusion, SEMA4D could be immobilized on titanium surfaces through NaOH hydrothermal treatment and self-assembly technology. Meanwhile, SEMA4D immobilization altered the characteristics of the titanium surfaces, which negatively regulated macrophage behaviors in the endothelial cell/macrophage indirect coculture model.

Analysis of Several Pathways for Efficient Killing of Prostate Cancer Stem Cells: A Central Role of NF-κB RELA

Prostate cancer is a common cause of death worldwide. Here, we isolated cancer stem cells (CSCs) from four adenocarcinomas of the prostate (Gleason scores from 3 + 3 up to 4 + 5). CSCs were characterized by the expression of the stem cell markers TWIST, the epithelial cell adhesion molecule (EPCAM), the transcription factors SNAI1 (SNAIL) and SNAI2 (SLUG) and cancer markers such as CD44 and prominin-1 (CD133). All investigated CSC populations contained a fraction highly positive for aldehyde dehydrogenase (ALDH) function and displayed robust expressions of programmed cell death 1 (PD-1) ligands. Furthermore, we investigated immunotherapeutic approaches but had no success even with the clinically used PD-1 inhibitor pembrolizumab. In addition, we studied another death-inducing pathway via interferon gamma signaling and detected high-level upregulations of human leukocyte antigen A (HLA-A) and beta 2-microglobulin (B2M) with only moderate killing efficacy. To examine further killing mechanisms in prostate cancer stem cells (PCSCs), we analyzed NF-κB signaling. Surprisingly, two patient-specific populations of PCSCs were found: one with canonical NF-κB signaling and another one with blunted NF-κB activation, which can be efficiently killed by tumor necrosis factor (TNF). Thus, culturing of PCSCs and analysis of respective NF-κB induction potency after surgery might be a powerful tool for optimizing patient-specific treatment options, such as the use of TNF-inducing chemotherapeutics and/or NF-κB inhibitors.

The MHC Class-I Transactivator NLRC5: Implications to Cancer Immunology and Potential Applications to Cancer Immunotherapy

The immune system constantly monitors the emergence of cancerous cells and eliminates them. CD8⁺ cytotoxic T lymphocytes (CTLs), which kill tumor cells and provide antitumor immunity, select their targets by recognizing tumor antigenic peptides presented by MHC class-I (MHC-I) molecules. Cancer cells circumvent immune surveillance using diverse strategies. A key mechanism of cancer immune evasion is downregulation of MHC-I and key proteins of the antigen processing and presentation machinery (APM). Even though impaired MHC-I expression in cancers is well-known, reversing the MHC-I defects remains the least advanced area of tumor immunology. The discoveries that NLRC5 is the key transcriptional activator of MHC-I and APM genes, and genetic lesions and epigenetic modifications of NLRC5 are the most common cause of MHC-I defects in cancers, have raised the hopes for restoring MHC-I expression. Here, we provide an overview of cancer immunity mediated by CD8⁺ T cells and the functions of NLRC5 in MHC-I antigen presentation pathways. We describe the impressive advances made in understanding the regulation of NLRC5 expression, the data supporting the antitumor functions of NLRC5 and a few reports that argue for a pro-tumorigenic role. Finally, we explore the possible avenues of exploiting NLRC5 for cancer immunotherapy.

Tumor-induced escape mechanisms and their association with resistance to checkpoint inhibitor therapy

Immunotherapy aims to activate the immune system to fight cancer in a very specific and targeted manner. Despite the success of different immunotherapeutic strategies, in particular antibodies directed against checkpoints as well as adoptive T-cell therapy, the response of patients is limited in different types of cancers. This attributes to escape of the tumor from immune surveillance and development of acquired resistances during therapy. In this review, the different evasion and resistance mechanisms that limit the efficacy of immunotherapies targeting tumor-associated antigens presented by major histocompatibility complex molecules on the surface of the malignant cells are summarized. Overcoming these escape mechanisms is a great challenge, but might lead to a better clinical outcome of patients and is therefore currently a major focus of research.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

A multiprotein complex consisting of the cellular coactivator p300, AP-1/ATF, as well as NF-kappaB is responsible for the activation of the mouse major histocompatibility class I (H-2K(b)) enhancer A

Major histocompatibility complex (MHC) class I genes encode highly polymorphic antigens that play an essential role in a number of immunological processes. Their expression is activated in response to a variety of signals and is mediated through several promoter elements among which the enhancer A is one of the key control regions. It contains binding sites for several transcription factors, for example: (i) a well-characterized binding site for rel/NF-kappaB transcription factors in its 3'-end (the H2TF1 or kappaB1 element), (ii) a second kappaB site (the kappaB2 element), which is located immediately adjacent 5' to the H2TF1 element and which is recognized by p65/relA in the human HLA system, and (iii) an AP-1/ATF recognition sequence in the 5' end (EnA-TRE). Here we demonstrate that latter element is bound by at least two distinct heterodimers of the AP-1/ATF transcription factor family, namely c-Jun/ATF-2 and c-Jun/Fra2. Moreover, our data reveal that the enhancer A is simultaneously bound by AP-1/ATF and rel/NF-kappaB transcription factors and that the cellular coactivator p300, which enhances enhancer A-driven reporter gene expression if cotransfected, is recruited to the enhancer A through this multiprotein complex. In contrast to the complete enhancer A, neither the EnA-TRE nor the H2TF1 element on their own are able to confer activation on a heterologous promoter in response to the phorbol ester tumor promoter TPA or the cytokine TNFalpha. Moreover, deletion of any one of the enhancer A control elements results in a dramatic loss of its inducibility by TNFalpha, and point mutations in either the EnA-TRE or the H2TF1 element lead to the loss of AP-1/ATF or NF-kappaB binding, respectively, and to the loss of enhancer A inducibility. Therefore, we conclude that the enhancer A is synergistically activated through a multiprotein complex containing AP-1/ATF, NF-kappaB transcription factors as well as the cellular coactivator p300.

Immunobiology of Inherited Muscular Dystrophies

The immune response to acute muscle damage is important for normal repair. However, in chronic diseases such as many muscular dystrophies, the immune response can amplify pathology and play a major role in determining disease severity. Muscular dystrophies are inheritable diseases that vary tremendously in severity, but share the progressive loss of muscle mass and function that can be debilitating and lethal. Mutations in diverse genes cause muscular dystrophy, including genes that encode proteins that maintain membrane strength, participate in membrane repair, or are components of the extracellular matrix or the nuclear envelope. In this article, we explore the hypothesis that an important feature of many muscular dystrophies is an immune response adapted to acute, infrequent muscle damage that is misapplied in the context of chronic injury. We discuss the involvement of the immune system in the most common muscular dystrophy, Duchenne muscular dystrophy, and show that the immune system influences muscle death and fibrosis as disease progresses. We then present information on immune cell function in other muscular dystrophies and show that for many muscular dystrophies, release of cytosolic proteins into the extracellular space may provide an initial signal, leading to an immune response that is typically dominated by macrophages, neutrophils, helper T-lymphocytes, and cytotoxic T-lymphocytes. Although those features are similar in many muscular dystrophies, each muscular dystrophy shows distinguishing features in the magnitude and type of inflammatory response. These differences indicate that there are disease-specific immunomodulatory molecules that determine response to muscle cell damage caused by diverse genetic mutations. © 2018 American Physiological Society. Compr Physiol 8:1313-1356, 2018.

Caffeine: Well-known as psychotropic substance, but little as immunomodulator

To date, numerable reviews are found in the literature prominent to the effect of caffeine on the immune system, with the latest review published in 2006. Database screening reveals around three thousand articles that have been published during the last decade. Interestingly, less than hundred articles involved humans and rodents as tested models, out of which 20% is of interest to this paper excluding studies done on the nervous and cardiac systems, and in pregnant and cancer cases. In this review, information pertaining to the experimental setup of various studies, namely, the tested model, the study type (in vivo or in vitro), and caffeine dose is covered to discern the behaviour of major cellular and molecular immune components in light of caffeine exposure. Although it is hard to extrapolate results done in rodents to humans and to relay conclusions from in vitro to in vivo studies, most of the collected data favor the suppressive effects of caffeine on the proliferation of stimulated lymphocytes. Macrophages and natural killer cells also exhibited a reduced activity in the presence of high caffeine doses compared to increased activity at low doses. Immunosuppression is also supported by reduced levels of major anti-inflammatory cytokines, IL-2, IL-6, TNF-α. Moreover, certain innate and adaptive immune receptors, such as TLR1, TLR2, TLR4, and MHC class I-related chain B (MICB) molecules, exhibited decreased expression levels. Thus, we support the use of caffeine to alleviate various inflammatory conditions and autoimmune diseases.

On the role of AP2 in epithelial-specific gene expression

Transcription factor AP2 plays an important role in transcription of keratin genes, and it has been suggested that AP2 confers epithelial specificity. Promoters of keratin genes contain AP2 sites, usually within tight clusters of binding sites for other nuclear transcription factors. The role of AP2 was examined by in vitro gel shift analysis, AP2 binding site mutagenesis, and stable and transient transfection experiments. Nonepithelial cells, such as GM10 fibroblasts and melanocytes, neither express keratin nor become phenotypically epithelial when transfected with an AP2-expressing vector. However, in 3T3 and HeLa cells, co-transfection of an AP2-expressing vector increases the level of transcription from keratin gene promoters. This increase requires an intact AP2 binding site. Thus, the role of AP2 in keratin gene expression is quantitative rather than qualitative. AP2 interacts with other transcription factors and may convey extracellular regulatory signals to the transcription complex in the promoters of keratin genes.

NLRP2 is a suppressor of NF-ƙB signaling and HLA-C expression in human trophoblasts†,‡

During pregnancy, fetal extravillous trophoblasts (EVT) play a key role in the regulation of maternal T cell and NK cell responses. EVT display a unique combination of human leukocyte antigens (HLA); EVT do not express HLA-A and HLA-B, but do express HLA-C, HLA-E, and HLA-G. The mechanisms establishing this unique HLA expression pattern have not been fully elucidated. The major histocompatibility complex (MHC) class I and class II transcriptional activators NLRC5 and CIITA are expressed neither by EVT nor by the EVT model cell line JEG3, which has an MHC expression pattern identical to that of EVT. Therefore, other MHC regulators must be present to control HLA-C, HLA-E, and HLA-G expression in these cells. CIITA and NLRC5 are both members of the nucleotide-binding domain, leucine-rich repeat (NLR) family of proteins. Another member of this family, NLRP2, is highly expressed by EVT and JEG3, but not in maternal decidual stromal cells. In this study, transcription activator-like effector nuclease technology was used to delete NLRP2 in JEG3. Furthermore, lentiviral delivery of shRNA was used to knockdown NLRP2 in JEG3 and primary EVT. Upon NLRP2 deletion, Tumor Necrosis Factor-α (TNFα)-induced phosphorylation of NF-KB p65 increased in JEG3 and EVT, and more surprisingly a significant increase in constitutive HLA-C expression was observed in JEG3. These data suggest a broader role for NLR family members in the regulation of MHC expression during inflammation, thus forming a bridge between innate and adaptive immune responses. As suppressor of proinflammatory responses, NLRP2 may contribute to preventing unwanted antifetal responses.

Genetic and epigenetic regulation of major histocompatibility complex class I gene expression in bovine trophoblast cells

Problem

The regulatory mechanisms governing differential expression of classical major histocompatibility complex (MHC) class I (MHC‐Ia) and non‐classical MHC class I (MHC‐Ib) genes are poorly understood.

Method of study

Quantitative reverse transcription‐ polymerase chain reaction (PCR) was used to compare the abundance of MHC‐I transcripts and related transcription factors in peripheral blood mononuclear cells (PBMC) and placental trophoblast cells (PTC). Methylation of MHC‐I CpG islands was detected by bisulfite treatment and next‐generation sequencing. Demethylation of PBMC and PTC with 5′‐aza‐deoxycytidine was used to assess the role of methylation in gene regulation.

Results

MHC‐I expression was higher in PBMC than PTC and was correlated with expression of IRF1, class II MHC transactivator (CIITA), and STAT1. The MHC‐Ia genes and BoLA‐NC1 were devoid of CpG methylation in PBMC and PTC. In contrast, CpG sites in the gene body of BoLA‐NC2, ‐NC3, and ‐NC4 were highly methylated in PBMC but largely unmethylated in normal PTC and moderately methylated in somatic cell nuclear transfer PTC. In PBMC, demethylation resulted in upregulation of MHC‐Ib by 2.8‐ to 6‐fold, whereas MHC‐Ia transcripts were elevated less than 2‐fold.

Conclusion

DNA methylation regulates bovine MHC‐Ib expression and is likely responsible for the different relative levels of MHC‐Ib to MHC‐Ia transcripts in PBMC and PTC.

Modulation of the transcription factor NF-κB in antigen-presenting cells by bovine respiratory syncytial virus small hydrophobic protein

Bovine respiratory syncytial virus (BRSV) is an important cause of respiratory disease in young cattle and is closely related to human RSV (HRSV), which causes severe respiratory disease in infants and the elderly. The RSV genome encodes a small hydrophobic (SH) protein with viroporin activity. Previous studies have shown that recombinant BRSV lacking the SH gene (rBRSVΔSH) is attenuated in the lungs, but not in the upper respiratory tract, of calves and mucosal vaccination with rBRSVΔSH induced long-lasting protective immunity. Attenuation of rBRSVΔSH may be due to the ability of this virus to induce an early innate response as rBRSVΔSH induces higher levels of pro-inflammatory cytokines than wild-type (wt) rBRSV. In this study, we investigated the effects of the BRSV SH protein on NF-κB p65 phosphorylation, a master step in the regulation of pro-inflammatory cytokines. Expression of SH resulted in the inhibition of NF-κB p65 phosphorylation in response to BRSV infection and extracellular lipopolysaccharide, and a reduction in the production of pro-inflammatory cytokines. In contrast, rBRSVΔSH does not inhibit NF-κB p65 phosphorylation in bovine antigen-presenting cells, including monocytes, macrophages and dendritic cells, resulting in increased expression of pro-inflammatory cytokines and increased activation of T cells compared to cells infected with wt BRSV. These findings highlight an important role for the BRSV SH protein in immune modulation.

NFκBiz protein downregulation in acute kidney injury: Modulation of inflammation and survival in tubular cells

Acute kidney injury is characterized by decreased renal function, tubular cell death and interstitial inflammation. The transcription factor NF-κB is a key regulator of genes involved in cell survival and the inflammatory response. In order to better understand the regulation and role of NF-κB in acute kidney injury we explored the expression of NF-κB-related genes in experimental acute kidney injury induced by a folic acid overdose. NFκBiz, a member of the IκB family of NF-κB regulators encoding NFκBiz, was among the top up-regulated NF-κB-related genes at the mRNA level in experimental acute kidney injury. However, the NFκBiz protein was constitutively expressed by normal tubular cells but was down-regulated in experimental acute kidney injury. Kidney NFκBiz mRNA upregulation and protein downregulation was also observed in acute kidney injury induced by cisplatin or unilateral kidney injury resulting from ureteral obstruction. Thus, we studied the consequences of NFκBiz protein downregulation by specific siRNA in cultured tubular epithelial cells. NFκBiz mRNA and protein were up-regulated by inflammatory cytokines (IL-1β or TWEAK/TNFα/IFNγ) and by LPS in cultured tubular cells. However, TWEAK only induced a very mild and short lived NFκBiz upregulation. NFκBiz targeting increased chemokine production and dampened Klotho downregulation induced by TWEAK, without modulating cell proliferation. NFκBiz targeting also rendered cells more resistant to apoptosis induced by serum deprivation or inflammatory cytokines. In conclusion, NFκBiz differentially regulates NF-κB-mediated responses of tubular cells to inflammatory cytokines in a gene-specific manner, and may be of potential therapeutic interest to limit inflammation in kidney disease.

Modulation of epithelial-to-mesenchymal cancerous transition by natural products

Metastasis is mainly responsible for poor prognosis of cancer, and epithelial-to-mesenchymal transition (EMT) is a significant process often activated during cancer invasion and metastasis. Therefore EMT could be an effective target of chemotherapy to inhibit cancer metastasis and improve prognosis. Considering that many chemotherapeutics are plant-based, we reviewed recent reports about natural products extracted from plants and cancer EMT prevention.

Toxicology of ambient particulate matter

It is becoming increasingly clear that inhalation exposure to particulate matter (PM) can lead to or exacerbate various diseases, which are not limited to the lung but extend to the cardiovascular system and possibly other organs and tissues. Epidemiological studies have provided strong evidence for associations with chronic obstructive pulmonary disease (COPD), asthma, bronchitis and cardiovascular disease, while the evidence for a link with lung cancer is less strong. Novel research has provided first hints that exposure to PM might lead to diabetes and central nervous system (CNS) pathology. In the current review, an overview is presented of the toxicological basis for adverse health effects that have been linked to PM inhalation. Oxidative stress and inflammation are discussed as central processes driving adverse effects; in addition, profibrotic and allergic processes are implicated in PM-related diseases. Effects of PM on key cell types considered as regulators of inflammatory, fibrotic and allergic mechanisms are described.

Identification and functional comparison of seven-transmembrane G-protein-coupled BILF1 receptors in recently discovered nonhuman primate lymphocryptoviruses

Coevolution of herpesviruses with their respective host has resulted in a delicate balance between virus-encoded immune evasion mechanisms and host antiviral immunity. BILF1 encoded by human Epstein-Barr virus (EBV) is a 7-transmembrane (7TM) G-protein-coupled receptor (GPCR) with multiple immunomodulatory functions, including attenuation of PKR phosphorylation, activation of G-protein signaling, and downregulation of major histocompatibility complex (MHC) class I surface expression. In this study, we explored the evolutionary and functional relationships between BILF1 receptor family members from EBV and 12 previously uncharacterized nonhuman primate (NHP) lymphocryptoviruses (LCVs). Phylogenetic analysis defined 3 BILF1 clades, corresponding to LCVs of New World monkeys (clade A) or Old World monkeys and great apes (clades B and C). Common functional properties were suggested by a high degree of sequence conservation in functionally important regions of the BILF1 molecules. A subset of BILF1 receptors from EBV and LCVs from NHPs (chimpanzee, orangutan, marmoset, and siamang) were selected for multifunctional analysis. All receptors exhibited constitutive signaling activity via G protein Gαi and induced activation of the NF-κB transcription factor. In contrast, only 3 of 5 were able to activate NFAT (nuclear factor of activated T cells); chimpanzee and orangutan BILF1 molecules were unable to activate NFAT. Similarly, although all receptors were internalized, BILF1 from the chimpanzee and orangutan displayed an altered cellular localization pattern with predominant cell surface expression. This study shows how biochemical characterization of functionally important orthologous viral proteins can be used to complement phylogenetic analysis to provide further insight into diverse microbial evolutionary relationships and immune evasion function.

IMPORTANCE

Epstein-Barr virus (EBV), known as an oncovirus, is the only human herpesvirus in the genus Lymphocryptovirus (LCV). EBV uses multiple strategies to hijack infected host cells, establish persistent infection in B cells, and evade antiviral immune responses. As part of EBV's immune evasion strategy, the virus encodes a multifunctional 7-transmembrane (7TM) G-protein-coupled receptor (GPCR), EBV BILF1. In addition to multiple immune evasion-associated functions, EBV BILF1 has transforming properties, which are linked to its high constitutive activity. We identified BILF1 receptor orthologues in 12 previously uncharacterized LCVs from nonhuman primates (NHPs) of Old and New World origin. As 7TM receptors are excellent drug targets, our unique insight into the molecular mechanism of action of the BILF1 family and into the evolution of primate LCVs may enable validation of EBV BILF1 as a drug target for EBV-mediated diseases, as well as facilitating the design of drugs targeting EBV BILF1.

Vascular relaxation induced by Eucommiae Ulmoides Oliv. and its compounds Oroxylin A and wogonin: implications on their cytoprotection action

The vascular relaxation action of Eucommiae Ulmoides Oliv. also known as Duzhong has been seen on arteries of the heart such as the aorta and the coronary artery which are elastic in nature. Duzhong is historically an active ingredient commonly used in hypertensive herbal prescriptions in China. This work investigated the vasodilating effect of Duzhong and its compounds (wogonin 10 μM and oroxylin-A) in the isolated intact rat heart, perfused retrograde according the method of Langendorff and the cytoprotective effect in EA.hy926 cell lines Coronary perfusion pressure was monitored with a pressure transducer connected to a side-arm of the aortic perfusion cannula. Duzhong induced vasorelaxation in a dose dependent manner, on precontracting the vessels with endothelin-1, Duzhong 10 mg/ml, wogonin 10 μM and oroxylin-A 10 μM could significantly lower the perfusion pressure in reference to positive control SNP, Duzhong induced vasodilation was not inhibited by L-NAME (nitric oxide inhibitor), but was significantly inhibited by Tetraethyl ammonium (TEA, a K(+) channel blocker and almost abolished by potassium chloride. The underlying mechanism was carried out in EA.hy926 cell lines. When these cells were treated with H2O2, there was higher expression of NOX-4, TNF-α and COX-2 mRNA. However, wogonin treatment attenuated the mRNA of NOX-4, TNF-α and COX-2. Wogonin also upregulated the mRNA expression of CAT, SOD-1 and GSR in oxidative stress induced by H2O2 EA.hy926 cells. Duzhong and compounds can exert an in vitro relaxation effect of the coronary artery and improve the heart function in Langendorff apparatus. This action appears to be endothelium dependent but not NO mediated. Cell culture findings indicated that wogonin can exert vascular and cellular protection by scavenging Reactive Oxygen Species.

Pulmonary toxicity in mice following exposure to cerium chloride

The widespread application of lanthanoids (Lns) in manufacturing industries has raised occupational and environmental health concerns about the possible increased health risks to humans exposed to Lns in their working and living environments. Numerous studies have shown that exposures to Ln cause pulmonary injury in animals, but very little is known about the molecular mechanisms of the pulmonary inflammation caused by cerium chloride (CeCl3) exposure. In this study, we evaluated the oxidative stress and molecular mechanism underlying with the pulmonary inflammation associated with chronic lung toxicity in mice treated with nasally instilled CeCl3 for 90 consecutive days. Our findings suggest that significant cerium accumulated in the lung, leading the obvious increase of the lung indices, significant increases in inflammatory cells and levels of lactate dehydrogenase, alkaline phosphate, and total protein, overproduction of reactive oxygen species and peroxidation of lipids, reduced antioxidant capacity, and pulmonary inflammation. CeCl3 exposure also activated nuclear factor κB, increased the expression of tumor necrosis factor α, cyclooxygenase-2, heme oxygenase 1, interleukin 2, interleukin 4, interleukin 6, interleukin 8, interleukin 10, interleukin 18, interleukin 1β, and CYP1A1. However, CeCl3 reduced the expression of nuclear factor κB (NF-κB)-inhibiting factor and heat shock protein 70. These findings suggest that the pulmonary inflammation caused by CeCl3 in mice is closely associated with oxidative stress and inflammatory cytokine expression.

Genetic, functional and molecular features of glucocorticoid receptor binding

Glucocorticoids (GCs) are key mediators of stress response and are widely used as pharmacological agents to treat immune diseases, such as asthma and inflammatory bowel disease, and certain types of cancer. GCs act mainly by activating the GC receptor (GR), which interacts with other transcription factors to regulate gene expression. Here, we combined different functional genomics approaches to gain molecular insights into the mechanisms of action of GC. By profiling the transcriptional response to GC over time in 4 Yoruba (YRI) and 4 Tuscans (TSI) lymphoblastoid cell lines (LCLs), we suggest that the transcriptional response to GC is variable not only in time, but also in direction (positive or negative) depending on the presence of specific interacting transcription factors. Accordingly, when we performed ChIP-seq for GR and NF-κB in two YRI LCLs treated with GC or with vehicle control, we observed that features of GR binding sites differ for up- and down-regulated genes. Finally, we show that eQTLs that affect expression patterns only in the presence of GC are 1.9-fold more likely to occur in GR binding sites, compared to eQTLs that affect expression only in its absence. Our results indicate that genetic variation at GR and interacting transcription factors binding sites influences variability in gene expression, and attest to the power of combining different functional genomic approaches.

IκB kinase β (IKKβ) inhibits p63 isoform γ (TAp63γ) transcriptional activity

Previously, we reported that IκB kinase-β(IKKβ) phosphorylates and stabilizes TAp63γ. However, the effect of this phosphorylation on TAp63γ transcriptional activity remains unclear. In this study, we showed that overexpression of IKKβ, but not its kinase dead mutant and IKKα, can surprisingly inhibit TAp63γ transcriptional activity as measured by luciferase assays and real-time PCR analyses of p63 target genes. This inhibition was impaired by ACHP, an IKKβ inhibitor, and enhanced by TNFα that activates IKKβ. Consistently, IKKβ inhibited the binding between TAp63γ and p300, a co-activator of TAp63γ, and consequently counteracted the positive effect of p300 on TAp63γ transcriptional activity. Through phosphorylation site prediction and mass spectrometry, we identified that Ser-4 and Ser-12 of p63 are IKKβ-targeting residues. As expected, IKKβ fails to suppress the transcriptional activity of the S4A/S12A double mutant p63. These results indicate that IKKβ can suppress TAp63γ activity by interfering with the interaction between TAp63γ and p300.

Amphisomal route of MHC class I cross-presentation in bacteria-infected dendritic cells

Dendritic cells (DCs) are among the first professional APCs encountered by the obligate intracellular bacterium Chlamydia during infection. Using an established mouse bone marrow-derived DC line, we show that DCs control chlamydial infection in multiple small inclusions characterized by restricted bacterial growth, impaired cytosolic export of the virulence factor chlamydial protease-like activity factor, and interaction with guanylate-binding protein 1, a host cell factor involved in the initiation of autophagy. During maturation of infected DCs, chlamydial inclusions disintegrate, likely because they lack chlamydial protease-like activity factor-mediated protection. Released cytosolic Chlamydia are taken up by autophagosomes and colocalize with cathepsin-positive amphisomal vacuoles, to which peptide transporter TAP and upregulated MHC class I (MHC I) are recruited. Chlamydial Ags are subsequently generated through routes involving preprocessing in amphisomes via cathepsins and entry into the cytosol for further processing by the proteasome. Finally, bacterial peptides are reimported into the endosomal pathway for loading onto recycling MHC I. Thus, we unravel a novel pathway of MHC I-mediated cross-presentation that is initiated with a host cellular attack physically disrupting the parasitophorous vacuole, involves autophagy to collect cytosolic organisms into autophagosomes, and concludes with complex multistep antigenic processing in separate cellular compartments.

Involvement of NF-κB in changes of IFN-γ-induced CIITA/MHC-II and iNOS expression by influenza virus in macrophages

Type II interferon (IFN-γ) plays an important role in defense against viral infection. Although this cytokine is found during influenza virus infection, it seems to have no protective function against the virus, and the reasons for this are not clear. To determine how the influenza virus overcomes the antiviral effects of IFN-γ, we examined the effect of A/Puerto-Rico/8/34 (H1N1) (PR8) infection on the expression of various IFN-γ inducible genes involved in defense against virus infection. The results showed that PR8 selectively affects IFN-γ induced MHC-II and iNOS expression in both the murine macrophage-like cell line, Raw264.7, and in primary alveolar macrophages. Infection of IFN-γ treated macrophages with PR8 resulted in decreased expression of CIITA/MHC-II and increased production of iNOS/NO. These changes correlate with activation of NF-κB but not with JAK/STAT signaling. The data indicate one possible mechanism underlying the ineffectiveness of IFN-γ against influenza virus, and suggest that NF-κB may be a promising target for anti-influenza drugs.

The clinically approved proteasome inhibitor PS-341 efficiently blocks influenza A virus and vesicular stomatitis virus propagation by establishing an antiviral state

Recently it has been shown that the proinflammatory NF-kappaB pathway promotes efficient influenza virus propagation. Based on these findings, it was suggested that NF-kappaB blockade may be a promising approach for antiviral intervention. The classical virus-induced activation of the NF-kappaB pathway requires proteasomal degradation of the inhibitor of NF-kappaB, IkappaB. Therefore, we hypothesized that inhibition of proteasomal IkappaB degradation should impair influenza A virus (IAV) replication. We chose the specific proteasome inhibitor PS-341, which is a clinically approved anticancer drug also known as Bortezomib or Velcade. As expected, PS-341 treatment of infected A549 cells in a concentration range that was not toxic resulted in a significant reduction of progeny virus titers. However, we could not observe the proposed suppression of NF-kappaB-signaling in vitro. Rather, PS-341 treatment resulted in an induction of IkappaB degradation and activation of NF-kappaB as well as the JNK/AP-1 pathway. This coincides with enhanced expression of antiviral genes, such as interleukin-6 and, most importantly, MxA, which is a strong interferon (IFN)-induced suppressor of influenza virus replication. This suggests that PS-341 may act as an antiviral agent via induction of the type I IFN response. Accordingly, PS-341 did not affect virus titers in Vero cells, which lack type I IFN genes, but strongly inhibited replication of vesicular stomatitis virus (VSV), a highly IFN-sensitive pathogen. Thus, we conclude that PS-341 blocks IAV and VSV replication by inducing an antiviral state mediated by the NF-kappaB-dependent expression of antivirus-acting gene products.

NF-kappaB dependent and independent mechanisms of quartz-induced proinflammatory activation of lung epithelial cells

In the initiation and progression of pulmonary inflammation, macrophages have classically been considered as a crucial cell type. However, evidence for the role of epithelial type II cells in pulmonary inflammation has been accumulating. In the current study, a combined in vivo and in vitro approach has been employed to investigate the mechanisms of quartz-induced proinflammatory activation of lung epithelial cells. In vivo, enhanced expression of the inflammation- and oxidative stress-related genes HO-1 and iNOS was found on the mRNA level in rat lungs after instillation with DQ12 respirable quartz. Activation of the classical NF-kappaB pathway in macrophages and type II pneumocytes was indicated by enhanced immunostaining of phospho-IkappaBalpha in these specific lung cell types. In vitro, the direct, particle-mediated effect on proinflammatory signalling in a rat lung epithelial (RLE) cell line was compared to the indirect, macrophage product-mediated effect. Treatment with quartz particles induced HO-1 and COX-2 mRNA expression in RLE cells in an NF-kappaB independent manner. Supernatant from quartz-treated macrophages rapidly activated the NF-kappaB signalling pathway in RLE cells and markedly induced iNOS mRNA expression up to 2000-fold compared to non-treated control cells. Neutralisation of TNFalpha and IL-1beta in macrophage supernatant did not reduce its ability to elicit NF-kappaB activation of RLE cells. In addition the effect was not modified by depletion or supplementation of intracellular glutathione. The results from the current work suggest that although both oxidative stress and NF-kappaB are likely involved in the inflammatory effects of toxic respirable particles, these phenomena can operate independently on the cellular level. This might have consequences for in vitro particle hazard testing, since by focusing on NF-kappaB signalling one might neglect alternative inflammatory pathways.

Synthesis and nuclear factor-kappaB inhibitory activities of 6- or 7-methylchroman-2-carboxylic acid N-(substituted) phenylamides

A series of 6- or 7-methylchroman-2-carboxylic acid N-(substituted) phenylamides (2a-s, 3a-s) were synthesized. Their abilities to inhibit nuclear factor-kappaB (NF-kappaB) activity were evaluated in lipopolysaccharide (LPS)-stimulated macrophage RAW 264.7 cells. Compounds with substituents such as -H, -CH(3), and -CF(3) on the phenyl ring were poor inhibitors of NF-kappaB. The most active NF-kappaB inhibitors contained 4-Cl (3s) and 4-OMe (3g) in the 7-methylchroman-2-carboxamide derivatives and 2-OH (2b) and 4-Cl (2s) in the 6-methylchroman-2-carboxamide derivatives (IC(50): 20.2-24.0 microM). These were slightly more potent than a reference compound, KL-1156 (1) (IC(50): 43.9 microM).

Monocytic differentiation of leukemic HL-60 cells induced by co-treatment with TNF-alpha and MK886 requires activation of pro-apoptotic machinery

The block of hematopoietic differentiation program in acute myeloid leukemia cells can be overcome by differentiating agent like retinoic acid, but it has several side effects. A study of other differentiation signaling pathways is therefore useful to predict potential targets of anti-leukemic therapy. We demonstrated previously that the co-treatment of HL-60 cells with Tumor necrosis factor-alpha (TNF-alpha) (1 ng/mL) and inhibitor of 5-lipoxygenase MK886 (5 microm) potentiated both monocytic differentiation and apoptosis. In this study, we detected enhanced activation of three main types of mitogen-activated protein kinases (MAPKs) (p38, c-Jun amino-terminal kinase [JNK], extracellular signal-regulated kinase [ERK]), so we assessed their role in differentiation using appropriate pharmacologic inhibitors. The inhibition of pro-apoptotic MAPKs (p38 and JNK) suppressed the effect of MK886 + TNF-alpha co-treatment. On the other hand, down-regulation of pro-survival ERK pathway led to increased differentiation. Those effects were accompanied by increased activation of caspases in cells treated by MK886 + TNF-alpha. Pan-caspase inhibitor ZVAD-fmk significantly decreased both number of apoptotic and differentiated cells. The same effect was observed after inhibition of caspase 9, but not caspase 3 and 8. To conclude, we evidenced that the activation of apoptotic processes and pathways supporting apoptosis (p38 and JNK MAPKs) is required for the monocytic differentiation of HL-60 cells.

Histone modifications, but not nucleosomal positioning, correlate with major histocompatibility complex class I promoter activity in different tissues in vivo

To examine the role of chromatin in transcriptional regulation of the major histocompatibility complex (MHC) class I gene, we determined nucleosome occupancy and positioning, histone modifications, and H2A.Z occupancy across its regulatory region in murine tissues that have widely different expression levels. Surprisingly, nucleosome occupancy and positioning were indistinguishable between the spleen, kidney, and brain. In all three tissues, the 200 bp upstream of the transcription start site had low nucleosome occupancy. In contrast, nuclease hypersensitivity, histone modifications, and H2A.Z occupancy showed tissue-specific differences. Thus, tissue-specific differences in MHC class I transcription correlate with histone modifications and not nucleosomal organization. Further, activation of class I transcription by gamma interferon or its inhibition by alpha-amanitin did not alter nucleosome occupancy, positioning, nuclease hypersensitivity, histone modifications, or H2A.Z occupancy in any of the tissues examined. Thus, chromatin remodeling was not required to dynamically modulate transcriptional levels. These findings suggest that the MHC class I promoter remains poised and accessible to rapidly respond to infection and environmental cues.

Inhibition of the promotion of hepatocarcinogenesis by 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) by the deletion of the p50 subunit of NF-kappa B in mice

Polychlorinated biphenyls (PCBs) are persistent and ubiquitous environmental chemicals that bioaccumulate and have hepatic tumor promoting activity in rodents. The present study examined the effect of deleting the p50 subunit of NF-kappaB on the hepatic tumor promoting activity of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) in mice. Both wild-type and p50-/- male mice were injected i.p. with diethylnitrosamine (DEN, 90 mg/kg) and then subsequently injected biweekly with 20 i.p. injections of PCB-153 (300 micromol/kg/injection). p50 deletion decreased the tumor incidence in both PCB- and vehicle-treated mice, whereas PCB-153 slightly (P=0.09) increased the tumor incidence in wild-type and p50-/- mice. PCB-153 increased the total tumor volume in both wild-type and p50-/- mice, but the total tumor volume was not affected by p50 deletion in either PCB- or vehicle-treated mice. The volume of tumors that were positive for glutamine synthetase (GS), which is indicative of mutations in the beta-catenin gene, was increased in both wild-type and p50-/- mice administered PCB-153 compared to vehicle controls, and inhibited in p50-/- mice compared to wild-type mice (in both PCB- and vehicle-treated mice). The volume of tumors that were negative for GS was increased in p50-/- mice compared to wild-type mice but was not affected by PCB-153. PCB-153 increased cell proliferation in normal hepatocytes in wild-type but not p50-/- mice; this increase was inhibited in p50-/- mice. In hepatic tumors, the rate of cell proliferation was much higher than in normal hepatocytes, but was not affected by PCB treatment or p50 deletion. The rate of apoptosis, as measured by the TUNEL assay, was not affected by PCB-153 or p50 deletion in normal hepatocytes. In hepatic tumors, the rate of apoptosis was lower than in normal hepatocytes; PCB-153 slightly (P=0.10) increased apoptosis in p50-/- but not wild-type mice; p50 deletion had no effect. Taken together, these data indicate that the absence of the NF-kappaB p50 subunit inhibits the promoting activity of PCB-153 and alters the proliferative and apoptotic changes in mouse liver in the response to PCBs.

Phosphorylation and stabilization of TAp63gamma by IkappaB kinase-beta

Post-translational modification of the p53 family members is key to their regulation. Here we report the phosphorylation of TAp63gamma, but not DeltaNp63gamma, by IkappaB kinase beta (IKKbeta). Activation of IKKbeta by gamma radiation or tumor necrosis factor-alpha led to increased TAp63gamma protein levels in cells. IKKbeta, but not its kinase-defective mutant IKKbeta-K44A, led to this observed stabilization of TAp63gamma. This stabilization of TAp63gamma in response to gamma radiation was significantly decreased in the absence of IKKbeta. Phosphorylation of TAp63gamma blocks ubiquitylation and possible degradation of this protein. We postulate that phosphorylation of TAp63gamma by IKKbeta stabilizes the TAp63gamma protein by blocking ubiquitylation-dependent degradation of this protein.

The nuclear I kappaB protein I kappaB zeta specifically binds NF-kappaB p50 homodimers and forms a ternary complex on kappaB DNA

Although they share sequence homology to classical cytoplasmic I kappaB inhibitors of transcription factor NF-kappaB, the proteins I kappaB zeta, Bcl-3, and I kappa BNS function in the nucleus as factors that influence NF-kappaB-dependent gene expression profiles. Through the use of purified recombinant proteins and by comparison with the classical I kappaB protein I kappaB alpha, we have discovered mechanistic details of the interaction between I kappaB zeta and functional NF-kappaB dimers. Whereas I kappaB alpha and other classical I kappaB proteins bind tightly to NF-kappaB dimers that possess the p65 subunit, I kappaB zeta binds preferentially to NF-kappaB p50 homodimers. This altered specificity is particularly interesting in light of the fact that both NF-kappaB subunits exhibit high sequence and structural homology, while the I kappaB alpha and I kappaB zeta proteins are also conserved in primary amino acid sequence. We further show that I kappaB zeta is capable of forming a stable ternary complex with the NF-kappaB p50 homodimer and kappaB DNA. Again, this is a stark contrast from I kappaB alpha, which inhibits NF-kappaB p65 homodimer binding to NF-kappaB target DNA sequences. Removal of the DNA sequences flanking the NF-kappaB binding site does not directly affect the interaction of p50 and I kappaB zeta. Rather, we have discovered that the carboxy-terminal glycine-rich region of the NF-kappaB p50 homodimer is involved in mediating high-affinity binding of I kappaB zeta and NF-kappaB p50. We conclude that the NF-kappaB p50 homodimer functions as a legitimate activator of gene expression through formation of a ternary complex between itself, I kappaB zeta, and DNA. The requirement for formation of this complex could explain why the nuclear I kappaB protein I kappaB zeta is absolutely required for expression of the pluripotent pro-inflammatory cytokine interleukin-6 in peritoneal macrophages.

NF-kappaB signaling regulates functional expression of the MHC class I-related neonatal Fc receptor for IgG via intronic binding sequences

The neonatal Fc receptor for IgG (FcRn) functions to transport maternal IgG to a fetus or newborn and to protect IgG from degradation. Although FcRn is expressed in a variety of tissues and cell types, the extent to which FcRn expression is regulated by immunological and inflammatory events remains unknown. Stimulation of intestinal epithelial cell lines, macrophage-like THP-1, and freshly isolated human monocytes with the cytokine TNF-alpha rapidly up-regulated FcRn gene expression. In addition, the TLR ligands LPS and CpG oligodeoxynucleotide enhanced the level of FcRn expression in THP-1 and monocytes. Treatment of TNF-stimulated THP-1 cells with the NF-kappaB-specific inhibitor or overexpression of a dominant negative mutant inhibitory NF-kappaB (IkappaBalpha; S32A/S36A) resulted in down-regulation of FcRn expression. By using chromatin immunoprecipitation we identified three NF-kappaB binding sequences within introns 2 and 4 of the human FcRn gene. An EMSA confirmed the p50/p50 and/or p65/p50 complex (s) bound to intron 2- or 4-derived oligonucleotides containing putative NF-kappaB binding sequences, respectively. The intronic NF-kappaB sequences in combination with the promoter or alone regulated the expression of a luciferase reporter gene in response to TNF-alpha stimulation or overexpression of NF-kappaB p65 and p50. DNA looping interactions potentially occurred after the stimulation between intronic NF-kappaB sequences and the FcRn promoter as shown by a chromosome conformation capture assay. Finally, TNF-alpha stimulations enhanced IgG transport across an intestinal Caco-2 epithelial monolayer. Together, these data provide the first evidence that NF-kappaB signaling via intronic sequences regulates FcRn expression and function.

Obesity-induced inflammation: a metabolic dialogue in the language of inflammation

Obesity induces an inflammation state that is implicated in many clinically important complications, including insulin resistance, diabetes, atherosclerosis and non-alcoholic fatty liver disease. Although the cause and the molecular participants in this process remain incompletely defined, adipose tissue has a central role. Obesity-induced production of pro-inflammatory molecules, typified by TNF-alpha was recognized more than a dozen years ago, and since then more than two dozen other pro-inflammatory molecules induced by obesity have been identified. More recently a critical role for immune cells, specifically mononuclear phagocytes, in generating the obesity-induced inflammation has been identified. Defining the molecular and cellular components of obesity-induced inflammation offers the potential of identifying therapeutic targets that can ameliorate the complications associated with obesity.

Inhibition of tumor growth by NF-kappaB inhibitors

NF-kappaB is a transcription factor that induces inflammatory cytokines and anti-apoptotic proteins. NF-kappaB is often constitutively activated in human cancers and leukemias, which might increase the malignant character of neoplastic diseases. Therefore, NF-kappaB inhibitors might be useful as anticancer agents. Our research team designed a new NF-kappaB inhibitor that is based on the structure of the antibiotic epoxyquomicin C isolated from a microorganism. The designed compound, DHMEQ, inhibited the ligand-induced activation of NF-kappaB, and it also inhibited the constitutively activated NF-kappaB in cancer cells. DHMEQ is a unique inhibitor of NF-kappaB that acts at the level of the nuclear translocation. It inhibited both canonical and non-canonical NF-kappaB activating pathways. It inhibited various carcinomas and leukemias in animal models without any toxicity, and might be useful as an anticancer agent.

Activation of NF-kappaB by the intracellular expression of NF-kappaB-inducing kinase acts as a powerful vaccine adjuvant

There is a pressing need for adjuvants that will enhance the effectiveness of genetic vaccines. This is particularly important in cancer and infectious disease such as HIV and malaria for which successful vaccines are desperately needed. Here, we describe an approach to enhance immunogenicity that involves the activation of NF-kappaB by the transgenic expression of an intracellular signaling molecule, NF-kappaB-inducing kinase (NIK). In vitro, NIK increases dendritic cell antigen presentation in allogeneic and antigen-specific T cell proliferation assays by potently activating NF-kappaB and consequently up-regulating the expression of cytokines (TNF-alpha, IL-6, IL-12, IL-15, and IL-18), chemokines [IL-8, RANTES (regulated on activation, normal T cell expressed and secreted), macrophage inflammatory protein-1alpha, monocyte chemoattractant protein-1, and monocyte chemoattractant protein-3], MHC antigen-presenting molecules (class I and II), and costimulatory molecules (CD80 and CD86). In vivo, NIK enhances immune responses against a vector-encoded antigen and shifts them toward a T helper 1 immune response with increased IgG2a levels, T cell proliferation, IFN-gamma production, and cytotoxic T lymphocyte responses more potently than complete Freund's adjuvant, a very efficacious T helper 1-inducing adjuvant. These findings define NIK, and possibly other inducers of NF-kappaB activation, as a potent adjuvant strategy that offers great potential for genetic vaccine development.

Zygote arrest 1 gene in pig, cattle and human: evidence of different transcript variants in male and female germ cells

BACKGROUND

Zygote arrest 1 (ZAR1) is one of the few known oocyte-specific maternal-effect genes essential for the beginning of embryo development discovered in mice. This gene is evolutionary conserved in vertebrates and ZAR1 protein is characterized by the presence of atypical plant homeobox zing finger domain, suggesting its role in transcription regulation. This work was aimed at the study of this gene, which could be one of the key regulators of successful preimplantation development of domestic animals, in pig and cattle, as compared with human.

METHODS

Screenings of somatic cell hybrid panels and in silico research were performed to characterize ZAR1 chromosome localization and sequences. Rapid amplification of cDNA ends was used to obtain full-length cDNAs. Spatio-temporal mRNA expression patterns were studied using Northern blot, reverse transcription coupled to polymerase chain reaction and in situ hybridization.

RESULTS

We demonstrated that ZAR1 is a single copy gene, positioned on chromosome 8 in pig and 6 in cattle, and several variants of correspondent cDNA were cloned from oocytes. Sequence analysis of ZAR1 cDNAs evidenced numerous short inverted repeats within the coding sequences and putative Pumilio-binding and embryo-deadenylation elements within the 3'-untranslated regions, indicating the potential regulation ways. We showed that ZAR1 expressed exclusively in oocytes in pig ovary, persisted during first cleavages in embryos developed in vivo and declined sharply in morulae and blastocysts. ZAR1 mRNA was also detected in testis, and, at lower level, in hypothalamus and pituitary in both species. For the first time, ZAR1 was localized in testicular germ cells, notably in round spermatids. In addition, in pig, cattle and human only shorter ZAR1 transcript variants resulting from alternative splicing were found in testis as compared to oocyte.

CONCLUSION

Our data suggest that in addition to its role in early embryo development highlighted by expression pattern of full-length transcript in oocytes and early embryos, ZAR1 could also be implicated in the regulation of meiosis and post meiotic differentiation of male and female germ cells through expression of shorter splicing variants. Species conservation of ZAR1 expression and regulation underlines the central role of this gene in early reproductive processes.

Transporter associated with antigen processing gene 1 codon 333 and codon 637 polymorphisms are associated with primary open-angle glaucoma

INTRODUCTION

Genetic factors in the immune system are widely suspected to have a role in the etiology of glaucoma. In this study, we evaluated the association between primary open-angle glaucoma (POAG) and the transporter associated with antigen processing (TAP) gene polymorphisms. The TAP gene polymorphisms we evaluated were TAP1-1 codon 333 A/G (Ile-Val), TAP1-2 codon 637 (Asp-Gly), TAP2-1 codon 379 (Val-Ile), TAP2-2 codon 665 (Thr-Ala) and codon 687 (Stop-Gln), and TAP2-3 codon 565 (Ala-Tht). Due to the lack of predictive markers for glaucoma, many glaucoma patients are only diagnosed when their visual acuity and visual field has irreversibly deteriorated. Our aim was to confirm whether or not the TAP1 and TAP2 genes can be used to identify suspectability to glaucoma.

METHODS

Sixty-six patients with POAG and 105 healthy volunteers were enrolled in this case-control study. We resolved the TAP1 and TAP2 gene polymorphisms by PCR-based analysis.

RESULTS

There was a significant difference in the distribution of TAP1-1 codon 333 and TAP1-2 codon 637 gene polymorphisms (p = 0.0375 and 0.01, respectively) between POAG patients and healthy controls. However, there was no significant difference between the two groups in TAP2-1 codon 370, TAP2-2 codon 665, and TAP2-3 codon 565 (p = 0.273, 0.19, and 0.131, respectively). In TAP1-1 codon 333, there was a significant difference between the "GG" homozygote and "GA" heterozygote (OR 4.32; 95% CI 1.336, 13.969). In TAP1-2 codon 637, there was a significant difference between the "GG" homozygote and "GA" heterozygote (OR 15; 95% CI 1.733, 129.860). There was also a significant difference between "GG" homozygote and "AA" homozygote (OR 10.8; 95% CI 1.286, 91.880). Therefore, TAP1-1 codon 333 and TAP1-2 codon 637 gene polymorphisms were useful genetic markers of POAG. The prevalence of the TAP1-2 "GG" homozygote differs significantly between POAG patients and healthy controls, although in the alleles of the both TAP genes, there were no significant differences between the two groups.

CONCLUSION

The immune system acts as an arbiter to help determine whether under stress a neuronal cell will survive or sacrifice itself to injuries. TAP1-1 and TAP1-2 play an important role in the immune system. TAP1-1 and TAP1-2 gene polymorphisms may, by way of post-transcriptional changes and altered regulation of gene expression, be involve the immune system in the development of POAG.

p21 (Waf1/Cip1) and FasL gene activation via Sp1 and NFkappaB is required for leukemia cell survival but not for cell death induced by diverse stimuli

The molecular mechanisms of the cellular response to different apoptotic effectors are only partially understood. Herein, the role of transcription factors, Sp1 and NFkappaB in differentiation-related and etoposide-induced apoptosis was examined in a number of human leukemia cell lines (HL-60, NB4, HEL, THP-1, K562). This was investigated with respect to the recruitment of one cell-cycle regulating gene, p21 and one cell death gene, FasL. Using electrophoretic mobility shift assay (EMSA), we consistently observed Sp1 and NFkappaB binding activity to the promoter of either gene during cell differentiation and the decrease associated with apoptosis upon long-term treatment with differentiation inducers in HL-60, NB4 and HEL cells. By contrast, Sp1 and NFkappaB binding capacities were lost in all myeloid cell lines undergoing etoposide-induced fast apoptosis. This effect was eliminated by the broad-spectrum caspase inhibitor, benzyloxycarbonyl-valinyl-alaninyl-aspartyl fluoromethylketone, thus restoring transcription factors' binding activity. However, sustained NFkappaB binding to the FasL promoter was noticed in apoptosis undergoing HEL cells treated by etoposide. Our results suggest that p21 and FasL gene activation is required for myeloid leukemia cell survival or maturation but not for cell death via Sp1 and NFkappaB as regulators of these genes. The findings also support the idea of a common mechanism for cellular responses to different apoptotic effectors in malignant hematopoietic cell lines.

Sp1 and NF-kappaB transcription factor activity in the regulation of the p21 and FasL promoters during promyelocytic leukemia cell monocytic differentiation and its associated apoptosis

Treatment of human acute promyelocytic leukemia cells with phorbol 12-myristate 13-acetate (PMA) results in growth arrest and differentiation toward monocytes, which subsequently die by apoptosis. However, the relationship between terminal differentiation and apoptosis remains unclear. Here we have studied Sp1 and nuclear factor kappaB (NF-kappaB) transcription factor activity in controlling promoters of cell cycle-regulating (p21/WAF1/CIP1) and cell death (FasL) genes during monocytic differentiation and apoptosis of the human acute promyelocytic leukemia cell lines NB4 and HL-60. Using the electrophoretic mobility shift assay, we observed that PMA treatment of NB4 cells caused an early response in Sp1 binding to the p21 and FasL promoters at 8 h. The firmly adherent cell phenotype, characteristic of differentiated cells, retained Sp1-binding activity to either promoter, but it was often lost completely in detached, apoptotic cells. The association of Sp1 with the p21 promoter during monocytic differentiation correlated with the levels of expressed p21 in the cytoplasmic fraction, as detected by immunoblotting. In HL-60 cells, very weak or no Sp1 binding to either promoter was observed. Low NF-kappaB affinity for its consensus sites and to the FasL promoter was characteristic of apoptotic cells. The results of this study suggest a positive role of Sp1 and NF-kappaB, as regulators of p21 and FasL genes, in leukemic cell survival and monocytic differentiation and a negative role in apoptotic cell death.