Heat shock protein 27 functions in inflammatory gene expression and transforming growth factor-beta-activated kinase-1 (TAK1)-mediated signaling

Molecular effects of polystyrene nanoplastics on human neural stem cells

Nanoplastics (NPs) have been found in many ecological environments (aquatic, terrestrial, air). Currently, there is great concern about the exposition and impact on animal health, including humans, because of the effects of ingestion and accumulation of these nanomaterials (NMs) in aquatic organisms and their incorporation into the food chain. NPs´ mechanisms of action on humans are currently unknown. In this study, we evaluated the altered molecular mechanisms on human neural stem cell line (hNS1) after 4 days of exposure to 30 nm polystyrene (PS) NPs (0.5, 2.5 and 10 μg/mL). Our results showed that NPs can induce oxidative stress, cellular stress, DNA damage, alterations in inflammatory response, and apoptosis, which could lead to tissue damage and neurodevelopmental diseases.

Regulation of mRNA stability contributes to the function of innate lymphoid cells in various diseases

Innate lymphoid cells (ILCs) are important subsets of innate immune cells that regulate mucosal immunity. ILCs include natural killer cells, innate lymphoid cells-1 (ILC1s), ILC2s, and ILC3s, which have extremely important roles in the immune system. In this review, we summarize the regulation of mRNA stability mediated through various factors in ILCs (e.g., cytokines, RNA-binding proteins, non-coding RNAs) and their roles in mediating functions in different ILC subsets. In addition, we discuss potential therapeutic targets for diseases such as chronic obstructive pulmonary disease, cancer, and pulmonary fibrosis by regulation of mRNA stability in ILCs, which may provide novel directions for future clinical research.

Angiotensin II Exaggerates SARS-CoV-2 Specific T-Cell Response in Convalescent Individuals following COVID-19

Dysregulation of renin−angiotensin systems during coronavirus disease 2019 (COVID-19) infection worsens the symptoms and contributes to COVID-19 severity and mortality. This study sought to investigate the effect of exogenous angiotensin II (Ang-II) on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T-cells response in recovered COVID-19 patients. Human peripheral blood mononuclear cells (PBMCs) were treated with Ang II and then stimulated with a SARS-CoV-2 peptide pool. T-cell responses were measured using flow cytometry, while enzyme-linked immunosorbent assay (ELISA) and intracellular cytokine staining (ICS) assays determined functional capability and polarization. Additionally, the relative level of protein phosphorylation was measured using a phosphokinase array. Our results showed that Ang II treatment significantly increased the magnitude of SARS-CoV-2-specific T-cell response in stimulated PBMCs with a SARS-CoV-2 peptide pool. Moreover, the phosphorylation levels of numerous proteins implicated in cardiovascular diseases, inflammation, and viral infection showed significant increases in the presence of Ang II. The mitogenic stimulation of PBMCs after Ang II and SARS-CoV-2 peptide pool stimulation showed functional polarization of T-cells toward Th1/Th17 and Th17 phenotypes, respectively. Meanwhile, ELISA showed increased productions of IL-1β and IL-6 in Ang II-stimulated PBMCs without affecting the IL-10 level. To our knowledge, this study is the first to demonstrate that Ang II exaggerates SARS-CoV-2-specific T-cells response. Therefore, during COVID-19 infection, Ang II may aggravate the inflammatory response and change the immune response toward a more inflammatory profile against SARS-CoV-2 infection.

HDAC6 regulates NF-κB signalling to control chondrocyte IL-1-induced MMP and inflammatory gene expression

Elevated pro-inflammatory signalling coupled with catabolic metalloproteinase expression is a common feature of arthritis, leading to cartilage damage, deterioration of the joint architecture and the associated pain and immobility. Countering these processes, histone deacetylase inhibitors (HDACi) have been shown to suppress matrix metalloproteinase (MMP) expression, block cytokine-induced signalling and reduce the cartilage degradation in animal models of the arthritis. In order to establish which specific HDACs account for these chondro-protective effects an HDAC1-11 RNAi screen was performed. HDAC6 was required for both the interleukin (IL)-1 induction of MMP expression and pro-inflammatory interleukin expression in chondrocytes, implicating an effect on NF-κB signalling. Depletion of HDAC6 post-transcriptionally up-regulated inhibitor of κB (IκB), prevented the nuclear translocation of NF-κB subunits and down-regulated NF-κB reporter activation. The pharmacological inhibition of HDAC6 reduced MMP expression in chondrocytes and cartilage collagen release. This work highlights the important role of HDAC6 in pro-inflammatory signalling and metalloproteinase gene expression, and identifies a part for HDAC6 in the NF-κB signalling pathway. By confirming the protection of cartilage this work supports the inhibition of HDAC6 as a possible therapeutic strategy in arthritis.

Heat Shock Proteins Alterations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease characterized by the attack of the immune system on the body's healthy joint lining and degeneration of articular structures. This disease involves an increased release of inflammatory mediators in the affected joint that sensitize sensory neurons and create a positive feedback loop to further enhance their release. Among these mediators, the cytokines and neuropeptides are responsible for the crippling pain and the persistent neurogenic inflammation associated with RA. More importantly, specific proteins released either centrally or peripherally have been shown to play opposing roles in the pathogenesis of this disease: an inflammatory role that mediates and increases the severity of inflammatory response and/or an anti-inflammatory and protective role that modulates the process of inflammation. In this review, we will shed light on the neuroimmune function of different members of the heat shock protein (HSPs) family and the complex manifold actions that they exert during the course of RA. Specifically, we will focus our discussion on the duality in the mechanism of action of Hsp27, Hsp60, Hsp70, and Hsp90.

High fat diet-induced brain damaging effects through autophagy-mediated senescence, inflammation and apoptosis mitigated by ginsenoside F1-enhanced mixture

Background

Herbal medicines are popular approaches to capably prevent and treat obesity and its related diseases. Excessive exposure to dietary lipids causes oxidative stress and inflammation, which possibly induces cellular senescence and contribute the damaging effects in brain. The potential roles of selective enhanced ginsenoside in regulating high fat diet (HFD)-induced brain damage remain unknown.

Methods

The protection function of Ginsenoside F1-enhanced mixture (SGB121) was evaluated by in vivo and in vitro experiments. Human primary astrocytes and SH-SY5Y cells were treated with palmitic acid conjugated Bovine Serum Albumin, and the effects of SGB121 were determined by MTT and lipid uptake assays. For in vivo tests, C57BL/6J mice were fed with high fat diet for 3 months with or without SGB121 administration. Thereafter, immunohistochemistry, western blot, PCR and ELISA assays were conducted with brain tissues.

Results and conclusion

SGB121 selectively suppressed HFD-induced oxidative stress and cellular senescence in brain, and reduced subsequent inflammation responses manifested by abrogated secretion of IL-6, IL-1β and TNFα via NF-κB signaling pathway. Interestingly, SGB121 protects against HFD-induced damage by improving mitophagy and endoplasmic reticulum-stress associated autophagy flux and inhibiting apoptosis. In addition, SGB121 regulates lipid uptake and accumulation by FATP4 and PPARα. SGB121 significantly abates excessively phosphorylated tau protein in the cortex and GFAP activation in corpus callosum. Together, our results suggest that SGB121 is able to favor the resistance of brain to HFD-induced damage, therefore provide explicit evidence of the potential to be a functional food.

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High fat diet induces oxidative stress and subsequent cellular senescence in mice brain.

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High fat diet induces pathologies in cortex and GFAP activation in corpus callosum.

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Ginsenoside F1-enhanced mixture ameliorates damaging effect by modulating autophagy flux and inflammation.

Role of E2F1/SPHK1 and HSP27 During Irradiation in a PMA-Induced Inflammatory Model

Background: Sphingosine kinase 1 (SPHK1) and heat shock protein 27 (HSP27) are important for antioxidant and anti-inflammatory effects after red light irradiation in an inflammatory model. Objective: The purpose of the present study was to evaluate whether SPHK1 and HSP27 work independently or are dependent on some other regulator after 625 nm light-emitting diode irradiation in the human keratinocyte (HaCaT) cell line. Methods: Differentially expressed genes (DEGs) were identified between groups with or without 625 nm photobiomodulation (PBM) in the inflammatory model. Potential transcription factors (TFs) of key DEGs were predicted using the iRegulon plugin. The mechanism was investigated by analyzing mRNA and protein expression levels, prostaglandin E2 levels, and intracellular reactive oxygen species (ROS) in phorbol 12-myristate 13-acetate (PMA)-induced HaCaT cells after 625 nm PBM. Results: A total of 6 TFs (e.g., E2F1) and 51 key DEGs (e.g., SPHK1) were identified after 625 nm PBM in PMA-stimulated HaCaT cells. E2F1 worked as a regulator of SPHK1; however, it did not affect HSP27. E2F1 knockdown drastically decreased the SPHK1 expression level and increased the intracellular ROS, as well as the expression levels of inflammation-related proteins in PMA-induced HaCaT cells. In addition, the inhibition of HSP27 decreased the anti-inflammatory effect of 625 nm PBM. Conclusions: E2F1 worked as a TF of SPHK1 and exhibited anti-inflammatory and antioxidative effects through SPHK1 in PMA-induced HaCaT cells after 625 nm PBM. HSP27 is essential for the 625 nm PBM-induced anti-inflammatory function. Therefore, E2F1/SPHK1 and HSP27 could be used as potential biomarkers for anti-inflammatory therapy with 625 nm PBM.

Neuroinflammatory processes are augmented in mice overexpressing human heat-shock protein B1 following ethanol-induced brain injury

Background

Heat-shock protein B1 (HSPB1) is among the most well-known and versatile member of the evolutionarily conserved family of small heat-shock proteins. It has been implicated to serve a neuroprotective role against various neurological disorders via its modulatory activity on inflammation, yet its exact role in neuroinflammation is poorly understood. In order to shed light on the exact mechanism of inflammation modulation by HSPB1, we investigated the effect of HSPB1 on neuroinflammatory processes in an in vivo and in vitro model of acute brain injury.

Methods

In this study, we used a transgenic mouse strain overexpressing the human HSPB1 protein. In the in vivo experiments, 7-day-old transgenic and wild-type mice were treated with ethanol. Apoptotic cells were detected using TUNEL assay. The mRNA and protein levels of cytokines and glial cell markers were examined using RT-PCR and immunohistochemistry in the brain. We also established primary neuronal, astrocyte, and microglial cultures which were subjected to cytokine and ethanol treatments. TNFα and hHSPB1 levels were measured from the supernates by ELISA, and intracellular hHSPB1 expression was analyzed using fluorescent immunohistochemistry.

Results

Following ethanol treatment, the brains of hHSPB1-overexpressing mice showed a significantly higher mRNA level of pro-inflammatory cytokines (Tnf, Il1b), microglia (Cd68, Arg1), and astrocyte (Gfap) markers compared to wild-type brains. Microglial activation, and 1 week later, reactive astrogliosis was higher in certain brain areas of ethanol-treated transgenic mice compared to those of wild-types. Despite the remarkably high expression of pro-apoptotic Tnf, hHSPB1-overexpressing mice did not exhibit higher level of apoptosis. Our data suggest that intracellular hHSPB1, showing the highest level in primary astrocytes, was responsible for the inflammation-regulating effects. Microglia cells were the main source of TNFα in our model. Microglia isolated from hHSPB1-overexpressing mice showed a significantly higher release of TNFα compared to wild-type cells under inflammatory conditions.

Conclusions

Our work provides novel in vivo evidence that hHSPB1 overexpression has a regulating effect on acute neuroinflammation by intensifying the expression of pro-inflammatory cytokines and enhancing glial cell activation, but not increasing neuronal apoptosis. These results suggest that hHSPB1 may play a complex role in the modulation of the ethanol-induced neuroinflammatory response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02070-2.

Comparative transcriptome analysis of three invasive leafminer flies provides insights into interspecific competition

Liriomyza spp. (Diptera: Agromyzidae) represent a group of economically-significant highly polyphagous pests of plants grown in field and greenhouse conditions. Liriomyza spp. share similar biological and morphological characteristics, and complex interspecific interactions have been documented among these species in various geographical regions. Where the displacement of one of these species by the other has been studied, no unique mechanisms have been identified as causing it. The impact of competitive factors (such as, insecticide tolerance, thermotolerance, and adaptability to cropping systems) may be unique to specific geographic regions of Liriomyza spp., but more research is needed to confirm these hypotheses. In this study, RNA-seq was used to determine the transcriptomes of three closely-related leafminers, e.g. L. sativae, L. trifolii, and L. huidobrensis. Over 20 Gb of clean reads were generated and assembled into unique transcriptomes, and 38,747 unigenes were annotated in different databases. In pairwise comparisons, L. trifolii and L. sativae had more up-regulated genes than L. huidobrensis. With respect to common differentially-expressed genes (Co-DEGs), the three leafminers exhibited distinct groups of highly-expressed gene clusters. When genes related to competitive factors were compared, expression patterns in L. trifolii and L. sativae were more closely related to each other than to L. huidobrensis. The data suggest that DEGs involved in competitive factors may play a key role in competition and displacement of leafminers. The divergent genes identified in this study will be valuable in revealing possible mechanisms of invasion, displacement and interspecific competition in Liriomyza spp.

Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development

Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.

Differential expression of immune-related genes in the bursa of Fabricius of two inbred chicken lines following infection with very virulent infectious bursal disease virus

Among different inbred chickens' lines, we previously showed that lines P and N of Institute for Animal Health, Compton, UK are the most susceptible and the least affected lines, respectively, following infection with very virulent infectious bursal disease virus (vvIBDV). In this study, the differential expressions of 29 different immune-related genes were characterized. Although, birds from both lines succumbed to infection, line P showed greater bursal lesion scores and higher viral copy numbers compared to line N. Interestingly, line N showed greater down-regulation of B cell related genes (BLNK, TNFSF13B and CD72) compared to line P. While up-regulation of T-cell related genes (CD86 and CTLA4) and Th1 associated cytokines (IFNG, IL2, IL12A and IL15) were documented in both lines, the expression levels of these genes were different in the two lines. Meanwhile, the expression of IFN-related genes IFNB, STAT1, and IRF10, but not IRF5, were up-regulated in both lines. The expression of pro-inflammatory cytokines (IL1B, IL6, IL18, and IL17) and chemokines (CXCLi2, CCL4, CCL5 and CCR5) were up-regulated in both lines with greater increase documented in line P compared to line N. Strikingly, the expression of IL12B was detected only in line P whilst the expression of IL15RA was detected only in line N. In conclusion, the bursal immunopathology of IBDV correlates more with expression of proinflammatory response related genes and does not related to expression of B-cell related genes.

Melanoma migration is promoted by prion protein via Akt-hsp27 signaling axis

Patients with metastatic melanoma have a poorer prognosis. Prion protein (PrP) in melanoma is known to play an important role in cancer cell migration and invasion by interacting with filamin A (FLNa), a cytolinker protein. To investigate if PrP may contribute to cancer cell mobility independent of its binding to FLNa, we knocked out PRNP in M2 melanoma cell, which lacked FLNa expression. We found that deletion of PRNP in M2 significantly reduced its motility. When PRNP was deleted, the level of Akt was decreased. As a consequence, phosphorylation of small heat shock protein (hsp27) was also reduced, which resulted in polymerization of F-actin rendering the cells less migratory. Accordingly, when PrP was re-expressed in PRNP null M2 cells, the mobility of the recurred cells was rescued, so were the expression levels of Akt and phosphorylated hsp27, resulting in a decrease in the polymerization of F-actin. These results revealed that PrP can play a FLNa independent role in cytoskeletal organization and tumor cell migration by modulating Akt-hsp27-F-actin axis.

Transcriptome analysis reveals global gene expression changes of Chilo suppressalis in response to sublethal dose of chlorantraniliprole

The anthranilic diamide insecticide chlorantraniliprole was widely used for the controlling of Chilo suppressalis in China. Previous studies have revealed sublethal effects of chlorantraniliprole on the development and reproduction of C. suppressalis. In the present study, a comparative transcriptome analysis was performed to investigate the global gene expression changes in third-instar larvae of C. suppressalis after exposure to LC₃₀ of chlorantraniliprole. A total of 908 differentially expressed genes (DEGs) were identified including 441 up-regulated and 467 down-regulated unigenes. Gene enrichment analysis revealed that the down-regulated DEGs were mainly linked to carbohydrate, energy, lipid and amino acid metabolisms as well as posttranslational modification, while most of the DEGs involved in signal transduction were up-regulated. Specifically, the DEGs encoding detoxification related genes were identified and validated by RT-qPCR. Our results provide a basis for understanding the molecular mechanisms of chlorantraniliprole action and detoxification in C. suppressalis and other insect pests.

Heat shock protein 70 is a positive regulator of airway inflammation and goblet cell hyperplasia in a mouse model of allergic airway inflammation

Heat shock proteins (Hsps) are highly conserved molecular chaperones that are ubiquitously expressed in all species to aid the solubilization of misfolded proteins, protein degradation, and transport. Elevated levels of Hsp70 have been found in the sputum, serum, and bronchoalveolar lavage (BAL) fluid of asthma patients and are known to correlate with disease severity. However, the function of Hsp70 in allergic airway inflammation has remained largely unknown. This study aimed to determine the role of Hsp70 in airway inflammation and remodeling using a mouse model of allergic airway inflammation. WT and Hsp70 double-knockout (Hsp70.1/.3^-/-) mice were sensitized and challenged intratracheally with Schistosoma mansoni soluble egg antigens (SEAs) to induce robust Th2 responses and airway inflammation in the lungs. The lack of Hsp70 resulted in a significant reduction in airway inflammation, goblet cell hyperplasia, and Th2 cytokine production, including IL-4, IL-5, and IL-13. An analysis of the BAL fluid suggested that Hsp70 is critically required for eosinophilic infiltration, collagen accumulation, and Th2 cytokine production in allergic airways. Furthermore, our bone marrow (BM) transfer studies show that SEA-induced airway inflammation, goblet cell hyperplasia, and Th2 cytokine production were attenuated in WT mice that were reconstituted with Hsp70-deficient BM, but these effects were not attenuated in Hsp70-deficient mice that were reconstituted with WT BM. Together, these studies identify a pathogenic role for Hsp70 in hematopoietic cells during allergic airway inflammation; this illustrates the potential utility of targeting Hsp70 to alleviate allergen-induced Th2 cytokines, goblet cell hyperplasia, and airway inflammation.

Considerations for the use of Cre recombinase for conditional gene deletion in the mouse lens

Background

Despite a number of different transgenes that can mediate DNA deletion in the developing lens, each has unique features that can make a given transgenic line more or less appropriate for particular studies. The purpose of this work encompasses both a review of transgenes that lead to the expression of Cre recombinase in the lens and a comparative analysis of currently available transgenic lines with a particular emphasis on the Le-Cre and P0-3.9GFPCre lines that can mediate DNA deletion in the lens placode. Although both of these transgenes are driven by elements of the Pax6 P0 promoter, the Le-Cre transgene consistently leads to ocular abnormalities in homozygous state and can lead to ocular defects on some genetic backgrounds when hemizygous.

Result

Although both P0-3.9GFPCre and Le-Cre hemizygous transgenic mice undergo normal eye development on an FVB/N genetic background, Le-Cre homozygotes uniquely exhibit microphthalmia. Examination of the expression patterns of these two transgenes revealed similar expression in the developing eye and pancreas. However, lineage tracing revealed widespread non-ocular CRE reporter gene expression in the P0-3.9GFPCre transgenic mice that results from stochastic CRE expression in the P0-3.9GFPCre embryos prior to lens placode formation. Postnatal hemizygous Le-Cre transgenic lenses express higher levels of CRE transcript and protein than the hemizygous lenses of P0-3.9GFPCre mice. Transcriptome analysis revealed that Le-Cre hemizygous lenses deregulated the expression of 15 murine genes, several of which are associated with apoptosis. In contrast, P0-3.9GFPCre hemizygous lenses only deregulated two murine genes. No known PAX6-responsive genes or genes directly associated with lens differentiation were deregulated in the hemizygous Le-Cre lenses.

Conclusions

Although P0-3.9GFPCre transgenic mice appear free from ocular abnormalities, extensive non-ocular CRE expression represents a potential problem for conditional gene deletion studies using this transgene. The higher level of CRE expression in Le-Cre lenses versus P0-3.9GFPCre lenses may explain abnormal lens development in homozygous Le-Cre mice. Given the lack of deregulation of PAX6-responsive transcripts, we suggest that abnormal eye development in Le-Cre transgenic mice stems from CRE toxicity. Our studies reinforce the requirement for appropriate CRE-only expressing controls when using CRE as a driver of conditional gene targeting strategies.

Electronic supplementary material

The online version of this article (10.1186/s40246-019-0192-8) contains supplementary material, which is available to authorized users.

Association between circulating levels of heat-shock protein 27 and aggressive periodontitis

Heat-shock protein (Hsp) 27 is a major intracellular molecular chaperone and controller of intracellular responses to inflammatory signals. In the extracellular space, recombinant Hsp27 has been described to exert anti-inflammatory activities. The aim of this study was to assess the association between circulating levels of Hsp27 and different types of periodontitis. Pro- and anti-inflammatory cytokines and the stress proteins Hsp27 and Hsp60 with proposed anti- and pro-inflammatory properties, respectively, were measured by two-site ELISA in the serum of patients with aggressive periodontitis (AgP, n = 30), chronic periodontitis (CP, n = 29) and periodontally healthy controls (H, n = 28). Furthermore, Hsp27 and Hsp60 levels were also measured longitudinally in 12 AgP patients at 6 time points up to 3 months after treatment. AgP patients had lower levels of Hsp27 compared to CP patients and healthy subjects (adjusted one-way ANOVA, p < 0.001, followed by post hoc Tukey HSD comparisons), while no differences in levels of Hsp60 or cytokines between the three groups were detected. In CP patients and H subjects, the systemic Hsp27 levels correlated with Hsp60 (r = 0.43, p < 0.001; r = 0.59, p < 0.001, respectively) and with pro-inflammatory cytokines TNF-α (r = 0.48, p < 0.001; r = 0.55, p < 0.001, respectively) and IL-6 (r = 0.44, p < 0.01). However, no such correlations were detected in AgP cases. No consistent temporal patterns of changes of Hsp27 concentration were detected across AgP patients following periodontal treatment. This study provides the first evidence that Hsp27 may be differentially expressed and regulated in AgP patients as compared with CP patients and healthy individuals.

The small heat shock protein HSPB1 protects mice from sepsis

In vitro studies have implicated the small heat shock protein HSPB1 in a range of physiological functions. However, its in vivo relevance is unclear as the phenotype of unstressed HSPB1^−/− mice is unremarkable. To determine the impact of HSPB1 in injury, HSPB1^−/− and wild type (WT) mice were subjected to cecal ligation and puncture, a model of polymicrobial sepsis. Ten-day mortality was significantly higher in HSPB1^−/− mice following the onset of sepsis (65% vs. 35%). Ex vivo mechanical testing revealed that common carotid arteries from HSPB1^−/− mice were more compliant than those in WT mice over pressures of 50–120 mm Hg. Septic HSPB1^−/− mice also had increased peritoneal levels of IFN-γ and decreased systemic levels of IL-6 and KC. There were no differences in frequency of either splenic CD4⁺ or CD8⁺ T cells, nor were there differences in apoptosis in either cell type. However, splenic CD4⁺ T cells and CD8⁺ T cells from HSPB1^−/− mice produced significantly less TNF and IL-2 following ex vivo stimulation. Systemic and local bacterial burden was similar in HSPB1^−/− and WT mice. Thus while HSPB1^−/− mice are uncompromised under basal conditions, HSPB1 has a critical function in vivo in sepsis, potentially mediated through alterations in arterial compliance and the immune response.

Mesenchymal MAPKAPK2/HSP27 drives intestinal carcinogenesis

Mesenchymal cells in the microenvironment of cancer exert important functions in tumorigenesis; however, little is known of intrinsic pathways that mediate these effects. MAPK signals, such as from MAPKAPK2 (MK2) are known to modulate tumorigenesis, yet their cell-specific role has not been determined. Here, we studied the cell-specific role of MK2 in intestinal carcinogenesis using complete and conditional ablation of MK2. We show that both genetic and chemical inhibition of MK2 led to decreased epithelial cell proliferation, associated with reduced tumor growth and invasive potential in the Apc^min/+ mouse model. Notably, this function of MK2 was not mediated by its well-described immunomodulatory role in immune cells. Deletion of MK2 in intestinal mesenchymal cells (IMCs) led to both reduced tumor multiplicity and growth. Mechanistically, MK2 in IMCs was required for Hsp27 phosphorylation and the production of downstream tumorigenic effector molecules, dominantly affecting epithelial proliferation, apoptosis, and angiogenesis. Genetic ablation of MK2 in intestinal epithelial or endothelial cells was less effective in comparison with its complete deletion, leading to reduction of tumor size via modulation of epithelial apoptosis and angiogenesis-associated proliferation, respectively. Similar results were obtained in a model of colitis-associated carcinogenesis, indicating a mesenchymal-specific role for MK2 also in this model. Our findings demonstrate the central pathogenic role of mesenchymal-specific MK2/Hsp27 axis in tumorigenesis and highlight the value of mesenchymal MK2 inhibition in the treatment of cancer.

Cellular Hsp27 interacts with classical swine fever virus NS5A protein and negatively regulates viral replication by the NF-κB signaling pathway

Classical swine fever virus (CSFV) nonstructural protein NS5A is a multifunctional protein functioning in regulation of viral genome replication, protein translation and assembly by interaction with viral or host proteins. Here, heat shock protein 27 (Hsp27) has been identified as a novel binding partner of NS5A by using His tag "pull down" coupled with shotgun LC-MS/MS, with interaction of both proteins further confirmed by co-immunoprecipitation and laser confocal assays. In PK-15 cells, silencing of Hsp27 expression by siRNA enhanced CSFV replication, and upregulation of Hsp27 inhibited viral proliferation. Additionally, we have shown that overexpression of Hsp27 increased NF-κB signaling induced by TNFα. Blocking NF-κB signaling in PK-15 cells overexpressing Hsp27 by ammonium pyrrolidinedithiocarbamate (PDTC) eliminated the inhibition of CSFV replication by Hsp27. These findings clearly demonstrate that the inhibition of CSFV replication by Hsp27 is mediated via the NF-κB signaling pathway.

The small heat shock proteins, especially HspB4 and HspB5 are promising protectants in neurodegenerative diseases

Small heat shock proteins (sHsps) are a group of proteins with molecular mass between 12 and 43 kDa. Currently, 11 members of this family have been classified, namely HspB1 to HspB11. HspB1, HspB2, HspB5, HspB6, HspB7, and HspB8, which are expressed in brain have been observed to be related to the pathology of neurodegenerative diseases, including Parkinson's, Alzheimer's, Alexander's disease, multiple sclerosis, and human immunodeficiency virus-associated dementia. Specifically, sHsps interact with misfolding and damaging protein aggregates, like Glial fibrillary acidic protein in AxD, β-amyloid peptides aggregates in Alzheimer's disease, Superoxide dismutase 1 in Amyotrophic lateral sclerosis and cytosine-adenine-guanine/polyglutamine (CAG/PolyQ) in Huntington's disease, Spinocerebellar ataxia type 3, Spinal-bulbar muscular atrophy, to reduce the toxicity or increase the clearance of these protein aggregates. The degree of HspB4 expression in brain is still debated. For neuroprotective mechanisms, sHsps attenuate mitochondrial dysfunctions, reduce accumulation of misfolded proteins, block oxidative/nitrosative stress, and minimize neuronal apoptosis and neuroinflammation, which are molecular mechanisms commonly accepted to mirror the progression and development of neurodegenerative diseases. The increasing incidence of the neurodegenerative diseases enhanced search for effective approaches to rescue neural tissue from degeneration with minimal side effects. sHsps have been found to exert neuroprotective functions. HspB5 has been emphasized to reduce the paralysis in a mouse model of experimental autoimmune encephalomyelitis, providing a therapeutic basis for the disease. In this review, we discuss the current understanding of the properties and the mechanisms of protection orchestrated by sHsps in the nervous system, highlighting the promising therapeutic role of sHsps in neurodegenerative diseases.

Tryptophan-Mediated Interactions between Tristetraprolin and the CNOT9 Subunit Are Required for CCR4-NOT Deadenylase Complex Recruitment

The zinc-finger protein tristetraprolin (TTP) binds to AU-rich elements present in the 3' untranslated regions of transcripts that mainly encode proteins of the inflammatory response. TTP-bound mRNAs are targeted for destruction via recruitment of the eight-subunit deadenylase complex "carbon catabolite repressor protein 4 (CCR4)-negative on TATA-less (NOT)," which catalyzes the removal of mRNA poly-(A) tails, the first obligatory step in mRNA decay. Here we show that a novel interaction between TTP and the CCR4-NOT subunit, CNOT9, is required for recruitment of the deadenylase complex. In addition to CNOT1, CNOT9 is now included in the identified CCR4-NOT subunits shown to interact with TTP. We find that both the N- and C-terminal domains of TTP are involved in an interaction with CNOT9. Through a combination of SPOT peptide array, site-directed mutagenesis, and bio-layer interferometry, we identified several conserved tryptophan residues in TTP that serve as major sites of interaction with two tryptophan-binding pockets of CNOT9, previously found to interact with another modulator GW182. We further demonstrate that these interactions are also required for recruitment of the CCR4-NOT complex and TTP-directed decay of an mRNA containing an AU-rich element in its 3'-untranslated region. Together the results reveal new molecular details for the TTP-CNOT interaction that shape an emerging mechanism whereby TTP targets inflammatory mRNAs for deadenylation and decay.

Small heat shock protein 27: An effective adjuvant for enhancement of HIV-1 Nef antigen-specific immunity

Novel vaccine modalities have been designed to improve the efficiency of vaccines against HIV infections. In this way, the HIV-1 Nef protein has been known as an attractive antigenic candidate in therapeutic vaccine development. Moreover, the endogenous adjuvants such as heat shock proteins (HSPs) and high mobility group box 1 protein (HMGB1) have been suggested effectively to induce antigen-specific humoral and cellular immune responses. In this study, different Nef DNA and protein constructs were produced in eukaryotic and prokaryotic expression systems, and their immunostimulatory properties were evaluated using small heat shock protein 27 (Hsp27) and the HMGB1-derived peptide (Hp91) in a mouse model. Generally, our results indicated that the Hsp27-Nef fusion DNA or protein could significantly elicit higher humoral and cellular immune responses than Nef DNA or protein, respectively. Analysis of the immune responses demonstrated that the Hsp27-Nef fusion protein, and also the mixture of Nef and Hp91 significantly enhanced the Nef-specific T cell responses. Indeed, these regimens induced high levels of IgG2a and IFN-γ directed toward Th1 responses and also Granzyme B secretion as compared to other immunization strategies. The immunostimulatory properties of Freund's adjuvant were significantly less than Hsp27 and Hp91 peptide in various immunization strategies. These findings showed that the use of Hsp27 and Hp91 in protein strategy could improve HIV-1 Nef-specific B- and T-cell immune responses, and also represent a promising HIV-1 vaccine candidate in future.

HSPB1 mutations causing hereditary neuropathy in humans disrupt non-cell autonomous protection of motor neurons

Heat shock protein beta-1 (HSPB1), is a ubiquitously expressed, multifunctional protein chaperone. Mutations in HSPB1 result in the development of a late-onset, distal hereditary motor neuropathy type II (dHMN) and axonal Charcot-Marie Tooth disease with sensory involvement (CMT2F). The functional consequences of HSPB1 mutations associated with hereditary neuropathy are unknown. HSPB1 also displays neuroprotective properties in many neuronal disease models, including the motor neuron disease amyotrophic lateral sclerosis (ALS). HSPB1 is upregulated in SOD1-ALS animal models during disease progression, predominately in glial cells. Glial cells are known to contribute to motor neuron loss in ALS through a non-cell autonomous mechanism. In this study, we examined the non-cell autonomous role of wild type and mutant HSPB1 in an astrocyte-motor neuron co-culture model system of ALS. Astrocyte-specific overexpression of wild type HSPB1 was sufficient to attenuate SOD1(G93A) astrocyte-mediated toxicity in motor neurons, whereas, overexpression of mutHSPB1 failed to ameliorate motor neuron toxicity. Expression of a phosphomimetic HSPB1 mutant in SOD1(G93A) astrocytes also reduced toxicity to motor neurons, suggesting that phosphorylation may contribute to HSPB1 mediated-neuroprotection. These data provide evidence that astrocytic HSPB1 expression may play a central role in motor neuron health and maintenance.

Broad-Spectrum Inhibition of Respiratory Virus Infection by MicroRNA Mimics Targeting p38 MAPK Signaling

The majority of antiviral therapeutics target conserved viral proteins, however, this approach confers selective pressure on the virus and increases the probability of antiviral drug resistance. An alternative therapeutic strategy is to target the host-encoded factors that are required for virus infection, thus minimizing the opportunity for viral mutations that escape drug activity. MicroRNAs (miRNAs) are small noncoding RNAs that play diverse roles in normal and disease biology, and they generally operate through the post-transcriptional regulation of mRNA targets. We have previously identified cellular miRNAs that have antiviral activity against a broad range of herpesvirus infections, and here we extend the antiviral profile of a number of these miRNAs against influenza and respiratory syncytial virus. From these screening experiments, we identified broad-spectrum antiviral miRNAs that caused >75% viral suppression in all strains tested, and we examined their mechanism of action using reverse-phase protein array analysis. Targets of lead candidates, miR-124, miR-24, and miR-744, were identified within the p38 mitogen-activated protein kinase (MAPK) signaling pathway, and this work identified MAPK-activated protein kinase 2 as a broad-spectrum antiviral target required for both influenza and respiratory syncytial virus (RSV) infection.

Serum Heat Shock Protein Levels and the Relationship of Heat Shock Proteins with Various Parameters in Chronic Obstructive Pulmonary Disease Patients

OBJECTIVES

Chronic Obstructive Pulmonary Disease (COPD) is accompanied by increased cellular stress and inflammation. Most of the Heat Shock Proteins (HSPs) have strong cytoprotective effects. The role of HSPs in COPD pathogenesis has not determined completely. We investigated the serum level of HSPs in COPD patients, smokers without COPD and healthy non-smoking controls. Also, we evaluated the relationship of HSPs with various parameters (inflammatory, oxidative, functional status, quality of life) in COPD patients.

MATERIAL AND METHODS

The levels of stress protein (HSP27, HSP70, HSP60, HSP90, CyPA), interleukin-6, C-reactive protein and malondialdehyde were measured in 16 healthy non-smoker, 14 smokers without COPD and 50 patients with stable COPD. Pulmonary function tests (PFT) and arterial blood gases parameters were measured. Health Related Quality of Life was evaluated and exercise capacity was measured with 6 minute walking test.

RESULTS

Only HSP27 levels was significantly higher in COPD patients when compared with both healthy non-smoker and smokers without COPD (for both, p< 0.001). There was a weak-moderate negative correlation between serum levels of HSP27 and PFT parameters and between HSP27 levels and PaO2. Serum levels of HSP27 showed a weak-moderate positive correlation with symptom, activity and total scores. Subjects evaluated only smokers without COPD and patients with COPD; HSP27 had an area under the curve (AUC) in the receiver operating characteristic (ROC) curve of 0.819 (0.702-0.935; 95% CI; p= 0.000).

CONCLUSION

Increased serum levels of HSP27 was found in COPD patients and our results showed sensitivity and specificity of serum HSP27 as diagnostic markers for COPD.

Microarray analysis of gene expression in olive flounder liver infected with viral haemorrhagic septicaemia virus (VHSV)

The most fatal viral pathogen in olive flounder Paralichthys olivaceus, is viral hemorrhagic septicemia virus, which afflicts over 48 species of freshwater and marine fish. Here, we performed gene expression profiling on transcripts isolated from VHSV-infected olive flounder livers using a 13 K cDNA microarray chip. A total of 1832 and 1647 genes were upregulated and down-regulated over two-fold, respectively, after infection. A variety of immune-related genes showing significant changes in gene expression were identified in upregulated genes through gene ontology annotation. These genes were grouped into categories such as antibacterial peptide, antigen-recognition and adhesion molecules, apoptosis, cytokine-related pathway, immune system, stress response, and transcription factor and regulatory factors. To verify the cDNA microarray data, we performed quantitative real-time PCR, and the results were similar to the microarray data. In conclusion, these results may be useful for the identification of specific genes or for the diagnosis of VHSV infection in flounder.

Analysis of protein expression in periodontal pocket tissue: a preliminary study

Background

The periodontal disease is caused by a set of inflammatory disorders characterized by periodontal pocket formation that lead to tooth loss if untreated. The proteomic profile and related molecular conditions of pocket tissue in periodontally-affected patients are not reported in literature. To characterize the proteomic profile of periodontally-affected patients, their interproximal periodontal pocket tissue was compared with that of periodontally-healthy patients. Pocket-associated and healthy tissue samples, harvested during surgical therapy, were treated to extract the protein content. Tissues were always collected at sites where no periodontal-pathogenic bacteria were detectable. Proteins were separated using two-dimensional gel electrophoresis and identified by liquid chromatography/mass spectrometry. After identification, four proteins were selected for subsequent Western Blot quantitation both in pathological and healty tissues.

Results

A significant unbalance in protein expression between healthy and pathological sites was recorded. Thirty-two protein spots were overall identified, and four proteins (S100A9, HSPB1, LEG7 and 14-3-3) were selected for Western blot analysis of both periodontally-affected and healthy patients. The four selected proteins resulted over-expressed in periodontal pocket tissue when compared with the corresponding tissue of periodontally-healthy patients. The results of Western blot analysis are congruent with the defensive and the regenerative reaction of injured periodontal tissues.

Conclusions

The proteomic analysis was performed for the first time directly on periodontal pocket tissue. The proteomic network highlighted in this study enhances the understanding of periodontal disease pathogenesis necessary for specific therapeutic strategies setting.

Mitogen-activated protein kinase-activated protein kinase 2 mediates resistance to hydrogen peroxide-induced oxidative stress in human hepatobiliary cancer cells

The development and progression of liver cancer are characterized by increased levels of reactive oxygen species (ROS). ROS-induced oxidative stress impairs cell proliferation and ultimately leads to cell death. Although liver cancer cells are especially resistant to oxidative stress, mechanisms of such resistance remain understudied. We identified the MAPK-activated protein kinase 2 (MK2)/heat shock protein 27 (Hsp27) signaling pathway mediating defenses against oxidative stress. In addition to MK2 and Hsp27 overexpression in primary liver tumors compared to adjacent nontumorous tissues, the MK2/Hsp27 pathway is activated by hydrogen peroxide-induced oxidative stress in hepatobiliary cancer cells. MK2 inactivation or inhibition of MK2 or Hsp27 expression increases caspase-3 and PARP cleavage and DNA breaks and therefore cell death. Interestingly, MK2/Hsp27 inhibition decreases antioxidant defenses such as heme oxygenase 1 through downregulation of the transcription factor nuclear factor erythroid-derived 2-like 2. Moreover, MK2/Hsp27 inhibition decreases both phosphorylation of epidermal growth factor receptor (EGFR) and expression of its ligand, heparin-binding EGF-like growth factor. A new identified partner of MK2, the scaffold PDZ protein EBP50, could facilitate these effects through MK2/Hsp27 pathway regulation. These findings demonstrate that the MK2/Hsp27 pathway actively participates in resistance to oxidative stress and may contribute to liver cancer progression.

Expression of Heat Shock Protein 27 in Benign Prostatic Hyperplasia with Chronic Inflammation

Background

Heat shock protein 27 (HSP 27) is known as a mediator in immune response and has been recently found to be expressed in prostate cancer. This study aimed to investigate the role of HSP27 in inflammatory BPH.

Material/Methods

Hospitalized BPH patients who received TURP were divided into 4 groups by the presence and degrees of chronic inflammation: non-inflammatory BPH (NI BPH), mild-inflammatory BPH (MI BPH), moderate-inflammatory BPH (MOI BPH), and severe-inflammatory BPH (SI BPH). Expressions of HSP 27, TNF-α, IL-6, and CD3 in prostate tissues and serum of patients were detected by immunohistochemistry and ELISA.

Results

Expression of HSP27 in BPH with histological inflammation was significantly higher than in non-inflammatory BPH. In inflammatory BPH groups, HSP27 expression gradually increased along with increasing inflammation. There was a significant correlation between the expression of TNF-α, IL-6, CD3 and HSP27 among different inflammatory BPH groups.

Conclusions

HSP27 expression level is associated with the degree of chronic inflammation in BPH and may participate in the pathological process in inflammatory BPH.

DNAJB3/HSP-40 cochaperone improves insulin signaling and enhances glucose uptake in vitro through JNK repression

Heat shock response (HSR) is an essential host-defense mechanism that is dysregulated in obesity-induced insulin resistance and type 2 diabetes (T2D). Our recent data demonstrated that DNAJB3 was downregulated in obese human subjects and showed negative correlation with inflammatory markers. Nevertheless, DNAJB3 expression pattern in diabetic subjects and its mode of action are not yet known. In this study, we showed reduction in DNAJB3 transcript and protein levels in PBMC and subcutaneous adipose tissue of obese T2D compared to obese non-diabetic subjects. Overexpression of DNAJB3 in HEK293 and 3T3-L1 cells reduced JNK, IRS-1 Ser-307 phosphorylation and enhanced Tyr-612 phosphorylation suggesting an improvement in IRS-1 signaling. Furthermore, DNAJB3 mediated the PI3K/AKT pathway activation through increasing AKT and AS160 phosphorylation. AS160 mediates the mobilization of GLUT4 transporter to the cell membrane and thereby improves glucose uptake. Using pre-adipocytes cells we showed that DNAJB3 overexpression caused a significant increase in the glucose uptake, possibly through its phosphorylation of AS160. In summary, our results shed the light on the possible role of DNAJB3 in improving insulin sensitivity and glucose uptake through JNK repression and suggest that DNAJB3 could be a potential target for therapeutic treatment of obesity-induced insulin resistance.

AGEs-Induced IL-6 Synthesis Precedes RAGE Up-Regulation in HEK 293 Cells: An Alternative Inflammatory Mechanism?

Advanced glycation end products (AGEs) can activate the inflammatory pathways involved in diabetic nephropathy. Understanding these molecular pathways could contribute to therapeutic strategies for diabetes complications. We evaluated the modulation of inflammatory and oxidative markers, as well as the protective mechanisms employed by human embryonic kidney cells (HEK 293) upon exposure to 200 μg/mL bovine serum albumine (BSA) or AGEs–BSA for 12, 24 and 48 h. The mRNA and protein expression levels of AGEs receptor (RAGE) and heat shock proteins (HSPs) 27, 60 and 70, the activity of antioxidant enzymes and the expression levels of eight cytokines were analysed. Cell damage via oxidative mechanisms was evaluated by glutathione and malondialdehyde levels. The data revealed two different time scale responses. First, the up-regulation of interleukin-6 (IL-6), HSP 27 and high catalase activity were detected as early as 12 h after exposure to AGEs–BSA, while the second response, after 24 h, consisted of NF-κB p65, RAGE, HSP 70 and inflammatory cytokine up-regulation, glutathione depletion, malondialdehyde increase and the activation of antioxidant enzymes. IL-6 might be important in the early ignition of inflammatory responses, while the cellular redox imbalance, RAGE activation and NF-κB p65 increased expression further enhance inflammatory signals in HEK 293 cells.

Quercetin attenuates cyclooxygenase-2 expression in response to acute ureteral obstruction

Unilateral ureteral obstruction (UUO) is associated with increased hydrostatic pressure, inflammation, and oxidative stress in the renal parenchyma. Previous studies have demonstrated marked cyclooxygenase (COX)-2 induction in renal medullary interstitial cells (RMICs) in response to UUO. The aim of the present study was to evaluate the effect of quercetin, a naturally occurring antioxidant, on COX-2 induction in vivo and in vitro. Rats subjected to 24 h of UUO were treated intraperitoneally with quercetin (50 mg·kg(-1)·day(-1)). Quercetin partly prevented COX-2 induction in the renal inner medulla in response to UUO. Moreover, RMICs exposed to conditions associated with obstruction, inflammation (produced by IL-1β), oxidative stress (produced by H2O2), and mechanical stress (produced by stretch) showed increased COX-2 expression. Interestingly, quercetin reduced COX-2 induction in RMICs subjected to stretched. Similarly, PGE2 production was markedly increased in RMICs exposed to stretch and was reversed to control levels by quercetin treatment. Furthermore, stretch-induced phosphorylation of ERK1/2 was blocked by quercetin, and inhibition of ERK1/2 attenuated stretch-induced COX-2 induction in RMICs. These results indicate that quercetin attenuated the induction of COX-2 expression and activity in RMICs exposed to mechanical stress as a consequence of acute UUO and that the MAPK ERK1/2 pathway might be involved in this quercetin-mediated reduction in COX-2.

Pseudolaric acid B inhibits T-cell mediated immune response in vivo via p38MAPK signal cascades and PPARγ activation

AIMS

Pseudolaric acid B (PAB) has been prescribed for its potent immunomodulatory effect. However, the detail of mechanism remains to be demonstrated. The purpose of this study is to further clarify the mechanism of PAB on T-cell mediated immune response in vivo.

MAIN METHODS

Investigations were carried to ascertain the pharmacological effect of PAB in a delayed-type hypersensitivity (DTH) mouse model of T-cell mediated immune response. Histological assessment was examined by hematoxylin and eosin staining. Affymetrix GeneChip® Mouse Genome 430 2.0 arrays were employed to evaluate the expression profile of PAB. Western blot was performed to detect p38MAPK signal cascades, including p38MAPK, ATF-2, MK2, and HSP27. Finally, TNF-α level was analyzed by ELISA, and Jurkat T cells were treated with PAB to determine its role on PPARγ activation using a reporter gene assay.

KEY FINDINGS

The results showed that PAB (5, 10, and 20mg/kg) could lead to a marked improvement for ear swelling and inflammatory infiltrate in DTH mice dose-dependently. According to the associated biological pathways from microarray analysis, PAB resulted in the restoration of abnormal immune-related gene expression linked to MAPK and PPAR signaling pathways. Moreover, PAB inhibited the activation of p38MAPK, ATF-2, MK2, and HSP27 significantly, as well as the production of TNF-α, which was reversed by GW9662, a specific antagonist for PPARγ. In addition, treatment with PAB also increased the transcriptional activity of PPARγ in a dose-dependent manner.

SIGNIFICANCE

These results provide us with novel insights into pharmacological action of PAB as a potential immunomodulator for the treatment of immune-related diseases.

Activation of p38 mitogen-activated protein kinase in ovalbumin and ozone-induced mouse model of asthma

BACKGROUND AND OBJECTIVE

Ozone exposure worsens the development of allergen-induced asthma. The p38 mitogen-activated protein kinase (MAPK) pathway plays an important role in the development of the inflammatory response, airway hyperresponsiveness (AHR) and airway remodelling. In this study, the role of the p38 MAPK pathway on the effects of chronic ozone exposure in ovalbumin (OVA)-sensitized and -challenged mice was investigated.

METHODS

Mice were sensitized and challenged with OVA followed by ozone exposure. Dexamethasone (Dex) and SB239063, a p38 MAPK inhibitor, were used as preventive treatment.

RESULTS

Compared with OVA-challenged mice, ozone exposure of OVA-challenged mice led to enhanced recruitment of inflammatory cells in bronchoalveolar lavage fluid, increases in inflammation scores, collagen accumulation, bronchial wall thickness and messenger RNA levels of inflammatory cytokines, along with activation of p38 MAPK/HSP27 and downregulation of MAPK phosphatase-1 (MKP-1) in the lung tissue. Dex treatment partially attenuated lung inflammation, while the cotreatment of Dex and SB239063 effectively reduced lung inflammation, inhibited airway remodelling, inactivated p38 MAPK/HSP27 and upregulated MKP-1 in the lung tissue.

CONCLUSIONS

Ozone exposure aggravated airway inflammation, airway remodelling, activation of p38 MAPK and downregulation of MKP-1 in OVA-sensitized and -challenged mice, which was ineffectively controlled by corticosteroids. p38 MAPK activation is a likely pathway involved in corticosteroid insensitivity.

Human myocardium releases heat shock protein 27 (HSP27) after global ischemia: the proinflammatory effect of extracellular HSP27 through toll-like receptor (TLR)-2 and TLR4

The myocardial inflammatory response contributes to cardiac functional injury associated with heart surgery obligating global ischemia/reperfusion (I/R). Toll-like receptors (TLRs) play an important role in the mechanism underlying myocardial I/R injury. The aim of this study was to examine the release of small constitutive heat shock proteins (HSPs) from human and mouse myocardium after global ischemia and examine the role of extracellular small HSP in myocardial injury. HSP27 release was assessed by enzyme-linked immunosorbent assay. Anti-HSP27 was applied to evaluate the role of extracellular HSP27 in the postischemic inflammatory response and functional injury in mouse hearts. Isolated hearts and cultured coronary vascular endothelial cells were exposed to recombinant HSP27 to determine its effect on proinflammatory signaling and production of proinflammatory mediators. HSP27 levels were markedly elevated in coronary sinus blood of patients and in coronary effluent of mouse hearts after global ischemia. Neutralizing extracellular HSP27 suppressed myocardial nuclear factor (NF)-κB activation and interleukin (IL)-6 production and improved cardiac function in mouse hearts. Perfusion of HSP27 to mouse hearts induced NF-κB activation and IL-6 production and depressed contractility. Further, recombinant HSP27 induced NF-κB phosphorylation and upregulated monocyte chemoattractant protein (MCP)-1 and intercellular adhesion molecule (ICAM)-1 production in both human and mouse coronary vascular endothelial cells. TLR2 knockout (KO) or TLR4 mutation abolished NF-κB phosphorylation and reduced MCP-1 and ICAM-1 production induced by extracellular HSP27 in endothelial cells. In conclusion, these results show that the myocardium releases HSP27 after global ischemia and that extracellular HSP27 is proinflammatory and contributes to the inflammatory mechanism of myocardial functional injury. Both TLR2 and TLR4 are involved in mediating the proinflammatory effect of extracellular HSP27.

The molecular mechanism for effects of TiN coating on NiTi alloy on endothelial cell function

The aim of this study is to systematically investigate the molecular mechanism of different effects of nickel titanium (NiTi) alloy surface and titanium nitride (TiN) coating on endothelial cell function. Release of nickel (Ni) ion from bare and TiN-coated NiTi alloys and proliferation of endothelial cells on the two materials were evaluated, and then influence of the two materials on cellular protein expression profiles was investigated by proteomic technology. Subsequently, proteomic data were analyzed with bioinformatics analyses and further validated using a series of biological experiments. Results showed that although the two materials did not affect cell proliferation, the Ni ions released from bare NiTi alloy generated inhibition on pathways associated with actin cytoskeleton, focal adhesion, energy metabolism, inflammation, and amino acid metabolism. In comparison, TiN coating not only effectively prevented release of Ni ions from NiTi alloy, but also promoted actin cytoskeleton and focal adhesion formation, increased energy metabolism, enhanced regulation of inflammation, and promoted amino acid metabolism. Furthermore, the two processes, "the initial mediation of adsorbed serum protein layer to endothelial cell adhesion and growth on the two materials" from our previous study, and "the following action of the two materials on cellular protein expression profile", were linked up and comprehensively analyzed. It was found that in stage of cell adhesion (within 4 h), release of Ni ions from bare NiTi alloy was very low, and the activation of adsorbed proteins to cell adhesion and growth related biological pathways (such as regulation of actin cytoskeleton, and focal adhesion pathways) was almost as same as TiN-coated NiTi alloy. This indicated that the released Ni ions did not affect the mediation of adsorbed proteins to endothelial cell adhesion. However, in stage of cell growth and proliferation, the release of Ni ions from bare NiTi alloy increased with time and reached a higher level, which inhibited endothelial cell function at molecular level, whereas TiN coating improved endothelial cell function.

The primary cilium influences interleukin-1β-induced NFκB signalling by regulating IKK activity

The primary cilium is an organelle acting as a master regulator of cellular signalling. We have previously shown that disruption of primary cilia assembly, through targeting intraflagellar transport, is associated with muted nitric oxide and prostaglandin responses to the inflammatory cytokine interleukin-1β (IL-1β). Here, we show that loss of the primary cilium disrupts specific molecular signalling events in cytosolic NFκB signalling. The induction of cyclooxygenase 2 (COX2) and inducible nitrous oxide synthase (iNOS) protein is abolished. Cells unable to assemble cilia exhibit unaffected activation of IκB kinase (IKK), but delayed and reduced degradation of IκB, due to diminished phosphorylation of inhibitor of kappa B (IκB) by IKK. This results in both delayed and reduced NFκB p65 nuclear translocation and nuclear transcript binding. We also demonstrate that heat shock protein 27 (hsp27), an established regulator of IKK, is localized to the ciliary axoneme and cellular levels are dramatically disrupted with loss of the primary cilium. These results suggest that the primary cilia compartment exerts influence over NFκB signalling. We propose that the cilium is a locality for regulation of the molecular events defining NFκB signalling events, tuning signalling as appropriate.

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Hypermorphic mutation of IFT88 results in partial loss of the primary cilium.

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Cilia loss leads to inhibition of COX2 and iNOS induction in response to IL-1.

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In cells without cilia, IKK is activated but does not phosphorylate IκB.

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This leads to sustained IκB expression, and reduced and mistimed NFκB signalling.

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We propose the cilium to be a location for hsp27 regulation of IKK activity.

Phosphorylation of heat shock protein 27 antagonizes TNF-α induced HeLa cell apoptosis via regulating TAK1 ubiquitination and activation of p38 and ERK signaling

Tumor necrosis factor (TNF)-α is a potent cytokine that regulates critical cellular processes including apoptosis. TNF-α usually triggers both survival and apoptotic signals in various cell types. Heat shock protein 27 (HSP27), an important cellular chaperone, is believed to protect cells from apoptosis. HSP27 can be phosphorylated and changed its cellular function according to different stimuli. However, available reports on the role of HSP27 phosphorylation in apoptosis remain elusive. In this study, we investigated the role of HSP27 phosphorylation in TNF-α induced apoptosis in human cervical carcinoma (HeLa) cells. We found that TNF-α induced apoptosis was enhanced if we suppressed the TNF-α induced HSP27 phosphorylation by specific inhibitor CMPD1 or MAPKAPK2 (MK2) knockdown or by overexpression of non-phosphorylatable mutant HSP27-3A. Through co-immunoprecipitation and confocal microscopy, we observed that HSP27 associated with transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) in response to TNF-α stimulation. By blocking MK2 activity or overexpressing phospho-mimetic mutant Hsp27-3D, we further showed that HSP27 phosphorylation facilitated the TNF-α induced ubiquitination and phosphorylation of TAK1 and the activations of p38 MAPK and ERK, the TAK1 downstream pro-survival signaling. In addition, we also found that increased HSP27 phosphorylation inhibited TRADD ubiquitination but did not influence the binding between TRADD and FADD in a pro-apoptotic complex. Taken together, our data indicated that HSP27 phosphorylation was involved in modulating the TNF-α induced apoptosis via interacting with TAK1 and regulating TAK1 post-translational modifications in HeLa cells. This study demonstrates that HSP27 phosphorylation serves as a novel regulator in TNF-α-induced apoptosis, and provides a new insight into the cytoprotective role of HSP27 phosphorylation.

HspB1, HspB5 and HspB4 in Human Cancers: Potent Oncogenic Role of Some of Their Client Proteins

Human small heat shock proteins are molecular chaperones that regulate fundamental cellular processes in normal unstressed cells as well as in many cancer cells where they are over-expressed. These proteins are characterized by cell physiology dependent changes in their oligomerization and phosphorylation status. These structural changes allow them to interact with many different client proteins that subsequently display modified activity and/or half-life. Nowdays, the protein interactomes of small Hsps are under intense investigations and will represent, when completed, key parameters to elaborate therapeutic strategies aimed at modulating the functions of these chaperones. Here, we have analyzed the potential pro-cancerous roles of several client proteins that have been described so far to interact with HspB1 (Hsp27) and its close members HspB5 (αB-crystallin) and HspB4 (αA-crystallin).

Heat shock protein B1-deficient mice display impaired wound healing

There is large literature describing in vitro experiments on heat shock protein (hsp)B1 but understanding of its function in vivo is limited to studies in mice overexpressing human hspB1 protein. Experiments in cells have shown that hspB1 has chaperone activity, a cytoprotective role, regulates inflammatory gene expression, and drives cell proliferation. To investigate the function of the protein in vivo we generated hspB1-deficient mice. HspB1-deficient fibroblasts display increased expression of the pro-inflammatory cytokine, interleukin-6, compared to wild-type cells, but reduced proliferation. HspB1-deficient fibroblasts exhibit reduced entry into S phase and increased expression of cyclin-dependent kinase inhibitors p27(kip1) and p21(waf1). The expression of hspB1 protein and mRNA is also controlled by the cell cycle. To investigate the physiological function of hspB1 in regulating inflammation and cell proliferation we used an excisional cutaneous wound healing model. There was a significant impairment in the rate of healing of wounds in hspB1-deficient mice, characterised by reduced re-epithelialisation and collagen deposition but also increased inflammation. HspB1 deficiency augments neutrophil infiltration in wounds, driven by increased chemokine (C-X-C motif) ligand 1 expression. This appears to be a general mechanism as similar results were obtained in the air-pouch and peritonitis models of acute inflammation.

Cellular stress response and innate immune signaling: integrating pathways in host defense and inflammation

Extensive research in the past decade has identified innate immune recognition receptors and intracellular signaling pathways that culminate in inflammatory responses. Besides its role in cytoprotection, the importance of cell stress in inflammation and host defense against pathogens is emerging. Recent studies have shown that proteins in cellular stress responses, including the heat shock response, ER stress response, and DNA damage response, interact with and regulate signaling intermediates involved in the activation of innate and adaptive immune responses. The effect of such regulation by cell stress proteins may dictate the inflammatory profile of the immune response during infection and disease. In this review, we describe the regulation of innate immune cell activation by cell stress pathways, present detailed descriptions of the types of stress response proteins and their crosstalk with immune signaling intermediates that are essential in host defense, and illustrate the relevance of these interactions in diseases characteristic of aberrant immune responses, such as chronic inflammatory diseases, autoimmune disorders, and cancer. Understanding the crosstalk between cellular stress proteins and immune signaling may have translational implications for designing more effective regimens to treat immune disorders.

Cross talk between the Akt and p38α pathways in macrophages downstream of Toll-like receptor signaling

The stimulation of Toll-like receptors (TLRs) on macrophages by pathogen-associated molecular patterns (PAMPs) results in the activation of intracellular signaling pathways that are required for initiating a host immune response. Both phosphatidylinositol 3-kinase (PI3K)-Akt and p38 mitogen-activated protein kinase (MAPK) signaling pathways are activated rapidly in response to TLR activation and are required to coordinate effective host responses to pathogen invasion. In this study, we analyzed the role of the p38-dependent kinases MK2/3 in the activation of Akt and show that lipopolysaccharide (LPS)-induced phosphorylation of Akt on Thr308 and Ser473 requires p38α and MK2/3. In cells treated with p38 inhibitors or an MK2/3 inhibitor, phosphorylation of Akt on Ser473 and Thr308 is reduced and Akt activity is inhibited. Furthermore, BMDMs deficient in MK2/3 display greatly reduced phosphorylation of Ser473 and Thr308 following TLR stimulation. However, MK2/3 do not directly phosphorylate Akt in macrophages but act upstream of PDK1 and mTORC2 to regulate Akt phosphorylation. Akt is recruited to phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the membrane, where it is activated by PDK1 and mTORC2. Analysis of lipid levels in MK2/3-deficient bone marrow-derived macrophages (BMDMs) revealed a role for MK2/3 in regulating Akt activity by affecting availability of PIP3 at the membrane. These data describe a novel role for p38α-MK2/3 in regulating TLR-induced Akt activation in macrophages.