Tumor necrosis factor alpha-induced E-selectin expression is activated by the nuclear factor-kappaB and c-JUN N-terminal kinase/p38 mitogen-activated protein kinase pathways

E-selectin-mediated rapid NLRP3 inflammasome activation regulates S100A8/S100A9 release from neutrophils via transient gasdermin D pore formation

S100A8/S100A9 is a proinflammatory mediator released by myeloid cells during many acute and chronic inflammatory disorders. However, the precise mechanism of its release from the cytosolic compartment of neutrophils is unclear. Here, we show that E-selectin-induced rapid S100A8/S100A9 release during inflammation occurs in an NLRP3 inflammasome-dependent fashion. Mechanistically, E-selectin engagement triggers Bruton's tyrosine kinase-dependent tyrosine phosphorylation of NLRP3. Concomitant potassium efflux via the voltage-gated potassium channel KV1.3 mediates ASC oligomerization. This is followed by caspase 1 cleavage and downstream activation of pore-forming gasdermin D, enabling cytosolic release of S100A8/S100A9. Strikingly, E-selectin-mediated gasdermin D pore formation does not result in cell death but is a transient process involving activation of the ESCRT III membrane repair machinery. These data clarify molecular mechanisms of controlled S100A8/S100A9 release from neutrophils and identify the NLRP3/gasdermin D axis as a rapid and reversible activation system in neutrophils during inflammation.

Ginsenoside Rg2 alleviates neurovascular damage in 3xTg-AD mice with Alzheimer's disease through the MAPK-ERK pathway

Alzheimer's disease (AD) is the most common form of dementia, and ginsenoside Rg2 (Rg2) is proven to inhibit AD's progression. This study investigates the potential benefits of Rg2 treatment on 3xTg-AD mice. Following 6 weeks of gavage treatment, Rg2-treated 3xTg-AD mice exhibited improved spatial recognition memory behaviors, regional cerebral blood flow, and histopathological injury of the hippocampus, which were observed through a Y-maze test, laser Doppler flowmetry, and hematoxylin-eosin staining. Additionally, Rg2 treatment caused a decrease in the levels of amyloid beta 25-35, TNF-α, IL-1β, and IL-6, as measured by enzyme-linked immunosorbent assay, as well as a reduction in mRNA levels of IL-1β and IL-6 in 3xTg-AD mouse brains using quantitative real-time PCR. In particular, NeuN and CD31 levels were inhibited and GFAP level was elevated in 3xTg-AD mice that were observed through immunofluorescence, and these levels were all antagonized by Rg2, suggesting the effects of Rg2 on neurovascular damage, astrocyte activation, and neuronal loss. Furthermore, Western blot and qRT-PCR assays showed that Rg2 blocked the expression of ICAM-1 and VCAM-1 in 3xTg-AD mice. By Western blot, the ratios of p-ERK/ERK and p-MAPK/MAPK in 3xTg-AD mice were upregulated by Rg2 treatment, suggesting the neuroprotective effects of Rg2 may be related to the MAPK-ERK pathway. In summary, this study demonstrated the potential of Rg2 to improve AD and provided a scientific basis for research on the biological mechanism of AD and the development of Rg2.

Long non coding RNAs reveal important pathways in childhood asthma: a future perspective

Asthma is a long-term inflammatory disease of the airways of the lungs refers changes that occur in conjunction with, or as a result of, chronic airway inflammation. Airway remodeling the subsequent of inflammation constitutes cellular and extracellular matrix changes in the wall airways, epithelial-to-mesenchymal-transition and airway smooth muscle cell proliferation. Diseases often begin in childhood and despite extensive research, causative pathogenic mechanisms still remain unclear. Transcriptome analysis of childhood asthma reveals distinct gene expression profiles of Long noncoding RNAs which have been reported to play a central regulatory role in various aspects of pathogenesis, clinical course and treatment of asthma. We briefly review current understanding of lnc-RNA dysregulation in children with asthma, focusing on their complex role in the inflammation, cell proliferation and remodeling of airway to guide future researches. We found that the lnc-RNAs increases activity of several oncogenes such c-Myc, Akt, and ERK and various signaling pathways such as MAPK (PI3K, Ras, JNK and p38), NF-κB and Wnt and crosstalk between these pathways by TGFβ, β-catenin, ERK and SKP2. Moreover, two different signal transduction pathways, Wnt and Notch1, can be activated by two lnc-RNAs through sponging the same miRNA for exacerbation cell proliferation.

Probing expression of E-selectin using CRISPR-Cas9-mediated tagging with HiBiT in human endothelial cells

E-selectin is expressed on endothelial cells in response to inflammatory cytokines and mediates leukocyte rolling and extravasation. However, studies have been hampered by lack of experimental approaches to monitor expression in real time in living cells. Here, NanoLuc Binary Technology (NanoBiT) in conjunction with CRISPR-Cas9 genome editing was used to tag endogenous E-selectin in human umbilical vein endothelial cells (HUVECs) with the 11 amino acid nanoluciferase fragment HiBiT. Addition of the membrane-impermeable complementary fragment LgBiT allowed detection of cell surface expression. This allowed the effect of inflammatory mediators on E-selectin expression to be monitored in real time in living endothelial cells. NanoBiT combined with CRISPR-Cas9 gene editing allows sensitive monitoring of real-time changes in cell surface expression of E-selectin and offers a powerful tool for future drug discovery efforts aimed at this important inflammatory protein.

Fucoxanthin prevents breast cancer metastasis by interrupting circulating tumor cells adhesion and transendothelial migration

Metastasis is the leading cause of cancer-related death and a critical challenge in improving cancer treatment today. Circulating tumor cells (CTCs) adhesion to and across the vascular endothelium are critical steps in the establishment of micrometastatic foci away from the primary tumor. Therefore, we believe that interrupting CTCs adhesion to endothelium and transendothelial migration may efficiently prevent cancer metastasis. Fucoxanthin (Fx) is an algal carotenoid widely distributed in brown algae, macroalgae, and diatoms. Previous studies have found that Fx has various pharmacological activities, including antidiabetic, antioxidant, anti-inflammatory, anti-obesity, antimalarial, anticancer, and so on. However, it remains unclear whether Fx has a preventive effect on cancer metastasis. Here, we found that Fx interrupts breast cancer cells MCF-7 adhesion to endothelium and transendothelial migration, thus inhibiting CTCs-based pulmonary metastasis in vivo. The hetero-adhesion assay showed that Fx significantly inhibited the expression of inflammatory factor-induced cell adhesion molecules (CAMs) and the resulting adhesion between MCF-7 cells and endothelial cells. The wound-healing and transwell assays showed that Fx significantly inhibited the motility, invasion, and transendothelial migration abilities of MCF-7 cells. However, the same concentration of Fx did not significantly alter the cell viability, cell cycle, apoptosis, and ROS of breast cancer cells, thus excluding the possibility that Fx inhibits MCF-7 cell adhesion and transendothelial migration through cytotoxicity. Mechanistically, Fx inhibits the expression of CAMs on endothelial cells by inhibiting the NF-кB signaling pathway by down-regulating the phosphorylation level of IKK-α/β, IкB-α, and NF-кB p65. Fx inhibits transendothelial migration of MCF-7 cells by inhibiting Epithelial-to-mesenchymal transition (EMT), PI3K/AKT, and FAK/Paxillin signaling pathways. Moreover, we demonstrated that Fx significantly inhibits the formation of lung micrometastatic foci in immunocompetent syngeneic mouse breast cancer metastasis models. We also showed that Fx enhances antitumor immune responses by substantially increasing the subsets of cytotoxic T lymphocytes in the peripheral immune system. This new finding provides a basis for the application of Fx in cancer metastatic chemoprevention and suggests that interruption of the CTCs adhesion to endothelium and transendothelial migration may serve as a new avenue for cancer metastatic chemoprevention.

SNHG5/miR-299-5p/ATF2 Axis as a Biomarker in Immune Microenvironment of Intervertebral Disc Degeneration

Methods

The data sets of GSE56081 and GSE63492 in the Gene Expression Omnibus (GEO) database were used for screening and analysis, and the key gene markers were verified by GSE34095 and GSE126883. Finally, the infiltration of immune cells in the data were analyzed by MCPcounter analysis package.

Results

In this study, a ceRNA containing 15 lncRNAs, 9 miRNAs, and 103 mRNAs was constructed. After multimodel screening and verification, key gene marker was found, namely, ATF2. The lncRNA/miRNA/mRNA axis closely related to ATF2 have also been found, namely, SNHG5/miR-299-5p/ATF2. In the analysis of immune infiltration, ATF2 was negatively correlated with T cells but positively correlated with neutrophils and endothelial cells.

Conclusion

The SNHG5/miR-299-5p/ATF2 can be used as biomarker of IDD, and infiltration of immune cells plays an important role in the pathological development of IDD. In addition, as a marker of IDD, the involvement of the above-mentioned axis in the pathological development of IDD remains to be further explored.

The promising therapeutic potentials of ginsenosides mediated through p38 MAPK signaling inhibition

The p38 mitogen-activated protein kinases (p38 MAPK) is a 38kD polypeptide recognized as the target for many potential anti-inflammatory agents. Accumulating evidence indicates that p38 MAPK could perform many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors. Ginseng is an exceptionally valued medicinal plant of the family Araliaceae (Panax genus). Recently, several studies targeted the therapeutic effects of purified individual ginsenoside, the most significant active ingredient of ginseng, and studied its particular molecular mechanism(s) of action rather than whole-plant extracts. Interestingly, several ginsenosides: ginsenosides compound K, F1, Rb1, Rb3, Rc, Rd, Re, Rf, Rg1, Rg2, Rg3, Rg5, Rh1, Rh2, Ro, notoginsenoside R1, and protopanaxadiol have shown to possess great therapeutic potentials mediated by their ability to downregulate p38 MAPK signaling in different cell lines and experimental animal models. Our review compiles the research findings of various ginsenosides as potent anti-inflammatory agents, highlighting the crucial role of p38 MAPK suppression in their pharmacological actions. In addition, in silico studies were conducted to explore the probable binding of these ginsenosides to p38 MAPK. The results obtained proposed p38 MAPK involvement in the beneficial pharmacological activities of ginsenosides in different ailments.

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p38 MAPK plays many roles in human disease pathophysiology. Therefore, great therapeutic benefits can be attained from p38 MAPK inhibitors.

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Several ginsenosides showed to possess great therapeutic potentials mediated by its ability to downregulate p38 MAPK signaling.

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in silico ​studies were conducted to explore the binding of these ginsenosides to p38 MAPK and evidenced the promising their inhibitory effect.

TRIM65 E3 ligase targets VCAM-1 degradation to limit LPS-induced lung inflammation

Although the adhesion molecules-mediated leukocyte adherence and infiltration into tissues is an important step of inflammation, the post-translational regulation of these proteins on the endothelial cells is poorly understood. Here, we report that TRIM65, an ubiquitin E3 ligase of tripartite protein family, selectively targets vascular cell adhesion molecule 1 (VCAM-1) and promotes its ubiquitination and degradation, by which it critically controls the duration and magnitude of sepsis-induced pulmonary inflammation. TRIM65 is constitutively expressed in human vascular endothelial cells. During TNFα-induced endothelial activation, the protein levels of TRIM65 and VCAM-1 are inversely correlated. Expression of wild-type TRIM65, but not expression of a TRIM65 mutant that lacks E3 ubiquitin ligase function in endothelial cells, promotes VCAM-1 ubiquitination and degradation, whereas small interference RNA-mediated knockdown of TRIM65 attenuates VCAM-1 protein degradation. Further experiments show that TRIM65 directly interacts with VCAM-1 protein and directs its polyubiquitination, by which TRIM65 controls monocyte adherence and infiltration into tissues during inflammation. Importantly, TRIM65-deficient mice are more sensitive to lipopolysaccharide-induced death, due to sustained and severe pulmonary inflammation. Taken together, our studies suggest that TRIM65-mediated degradation of VCAM-1 represents a potential mechanism that controls the duration and magnitude of inflammation.

Ribosomal stress-surveillance: three pathways is a magic number

Cells rely on stress response pathways to uphold cellular homeostasis and limit the negative effects of harmful environmental stimuli. The stress- and mitogen-activated protein (MAP) kinases, p38 and JNK, are at the nexus of numerous stress responses, among these the ribotoxic stress response (RSR). Ribosomal impairment is detrimental to cell function as it disrupts protein synthesis, increase inflammatory signaling and, if unresolved, lead to cell death. In this review, we offer a general overview of the three main translation surveillance pathways; the RSR, Ribosome-associated Quality Control (RQC) and the Integrated Stress Response (ISR). We highlight recent advances made in defining activation mechanisms for these pathways and discuss their commonalities and differences. Finally, we reflect on the physiological role of the RSR and consider the therapeutic potential of targeting the sensing kinase ZAKα for treatment of ribotoxin exposure.

Humoral factors secreted from adipose tissue-derived mesenchymal stem cells ameliorate atherosclerosis in Ldlr-/- mice

AIMS

Atherosclerosis is a chronic inflammatory disease of the vasculature. Mesenchymal stem cells (MSCs) exert immunomodulatory and immunosuppressive effects by secreting humoral factors; however, the intravascular MSC administration presents a risk of vascular occlusion. Here, we investigated both the effect of conditioned medium from cultured MSCs (MSC-CM) on atherosclerosis and the underlying mechanism.

METHODS AND RESULTS

Low-density lipoprotein receptor-deficient (Ldlr-/-) mice were fed a high-fat diet and received intravenous injections of either MSC-CM from adipose tissue-derived MSCs or control medium 2×/week for 13 weeks. MSC-CM treatment decreased the atherosclerotic plaque area in the aorta and aortic root of Ldlr-/- mice by 41% and 30%, respectively, with no change in serum lipoprotein levels. Histopathologically, the MSC-CM treatment decreased the expression of cell adhesion molecules (CAMs) and the accumulation of macrophages on the vascular walls. Extracellular vesicles (EVs) and supernatant (MSC-CM supernatant) were separated from the MSC-CM by ultracentrifugation. In tumour necrosis factor-α stimulated human aortic endothelial cells (HAOECs), both the MSC EVs and MSC-CM supernatant decreased CAM expression by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NFκB) pathways. In macrophages, the MSC-CM supernatant decreased the lipopolysaccharide-induced increases in M1 marker expression by inhibiting both the MAPK and NFκB pathways and increased the expression of M2 markers by activating the signal transducer and activator of transcription 3 pathway. In co-culture, inflamed HAOECs pretreated with MSC-CM supernatant and MSC EVs exhibited decreased monocyte adhesion to HAOECs. In addition, the neutralization of hepatocyte growth factor (HGF) in MSC-CM or MSC-CM supernatant attenuated their abilities to suppress monocyte adhesion to HAOECs in co-culture.

CONCLUSION

MSC-CM ameliorated atherosclerosis in Ldlr-/- mice and suppressed CAM expression and macrophage accumulation in the vascular walls. Humoral factors, including HGF and EVs from MSCs, hold promise as therapeutic agents to reduce the residual risk of coronary artery diseases.

Importance of TNF-alpha and its alterations in the development of cancers

TNF-alpha is involved in many physiologic and pathologic cellular pathways, including cellular proliferation, differentiation, and death, regulation of immunologic reactions to different cells and molecules, local and vascular invasion of neoplasms, and destruction of tumor vasculature. It is obvious that because of integrated functions of TNF-alpha inside different physiologic systems, it cannot be used as a single-agent therapy for neoplasms; however, long-term investigation of its different cellular pathways has led to recognition of a variety of subsequent molecules with more specific interactions, and therefore, might be suitable as prognostic and therapeutic factors for neoplasms. Here, we will review different aspects of the TNF-alpha as a cytokine involved in both physiologic functions of cells and pathologic abnormalities, most importantly, cancers.

Protective effect of hydrogen sulfide on experimental testicular ischemia reperfusion in rats

AIM

Testicular torsion is an urgent urological condition. Ischemia-reperfusion (I/R) processes that occur after detorsion as a treatment for torsion are caused by testicular injury. The purpose of our study is investigating the protecting effect of hydrogen sulfide (H₂S) on the testicular ischemia reperfusion injury.

MATERIALS AND METHODS

Thirty-eight Wistar-Albino rats were divided randomly into 6 different groups: Control (6); sham (6); IR-E (6)-2 h of torsion and 4 h of reperfusion; IR-E + H₂S (6)-in addition to the IR-E group, 75 μmol/kg of sodium hydrogen sulfide (NaHS) was administered intraperitoneally 30 min before reperfusion; IR-L (7)-2 h of torsion and 24 h of reperfusion; IR-L + H₂S (7)-in addition to the IR-L group, 75 μmol/kg NaHS was administered intraperitoneally 30 min before reperfusion. Biochemically, nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), reductive glutathione (GSH), and tumor TNF-α levels were measured in the testis. Serum TNF-α levels were also measured. Hematoxylin and eosin (H & E) was used for histopathological staining and microscopic findings were examined. The Johnsen score was performed to assess spermatogenesis activity in the testis. Apoptosis protease activating factor-1 (Apaf-1) and inducible nitric oxide synthase (iNOS) activity were evaluated immunohistochemically as well. Statistical analyses were made by the Chi-squared test and one-way analysis of variance.

RESULTS

MDA and NO levels were significantly increased in the IR-L group compared with sham and which decreased by the addition of H₂S treatment to the IR-L group (p < 0.05) in biochemical evaluation. GSH vs SOD levels were decreased in the IR-L group compared with sham and which increased by the addition of H₂S treatment to the IR-L group, but this correlations were not statistically significant (p > 0.05). Tissue and serum TNF-α levels were significantly increased in the IR-E group compared with sham and which decreased by the addition of H₂S treatment to the IR-E group. Johnsen score was the lowest in IR-L group (p < 0.05). Apaf-1 and iNOS activity were significantly increased in the IR-L group compared with sham and which decreased by the addition of H₂S treatment to the IR-L group (p < 0.05) in immunohistochemical evaluation.

CONCLUSIONS

First, the authors would like to say that H₂S treatment is protective and it is against ischemia reperfusion injury in testicular torsion. The anti-inflammatory, antioxidant, and antiapoptotic properties of H₂S caused protective effect as shown in this study.

Atheroprone flow activates inflammation via endothelial ATP-dependent P2X7-p38 signalling

Objective

Atherosclerosis is a focal disease occurring at arterial sites of disturbed blood flow that generates low oscillating shear stress. Endothelial inflammatory signalling is enhanced at sites of disturbed flow via mechanisms that are incompletely understood. The influence of disturbed flow on endothelial adenosine triphosphate (ATP) receptors and downstream signalling was assessed.

Methods and results

Cultured human endothelial cells were exposed to atheroprotective (high uniform) or atheroprone (low oscillatory) shear stress for 72 h prior to assessment of ATP responses. Imaging of cells loaded with a calcium-sensitive fluorescent dye revealed that atheroprone flow enhanced extracellular calcium influx in response to 300 µM 2'(3')-O-(4-Benzoylbenzoyl) adenosine-5'-triphosphate. Pre-treatment with pharmacological inhibitors demonstrated that this process required purinergic P2X7 receptors. The mechanism involved altered expression of P2X7, which was induced by atheroprone flow conditions in cultured cells. Similarly, en face staining of the murine aorta revealed enriched P2X7 expression at an atheroprone site. Functional studies in cultured endothelial cells showed that atheroprone flow induced p38 phosphorylation and up-regulation of E-selectin and IL-8 secretion via a P2X7-dependent mechanism. Moreover, genetic deletion of P2X7 significantly reduced E-selectin at atheroprone regions of the murine aorta.

Conclusions

These findings reveal that P2X7 is regulated by shear forces leading to its accumulation at atheroprone sites that are exposed to disturbed patterns of blood flow. P2X7 promotes endothelial inflammation at atheroprone sites by transducing ATP signals into p38 activation. Thus P2X7 integrates vascular mechanical responses with purinergic signalling to promote endothelial dysfunction and may provide an attractive potential therapeutic target to prevent or reduce atherosclerosis.

Cold Physical Plasma Modulates p53 and Mitogen-Activated Protein Kinase Signaling in Keratinocytes

Small reactive oxygen and nitrogen species (ROS/RNS) driven signaling plays a significant role in wound healing processes by controlling cell functionality and wound phase transitions. The application of cold atmospheric pressure plasma (CAP), a partially ionized gas expelling a variety of ROS and RNS, was shown to be effective in chronic wound management and contrastingly also in malignant diseases. The underlying molecular mechanisms are not well understood but redox signaling events are involved. As a central player, the cellular tumor antigen p53 governs regulatory networks controlling proliferation, death, or metabolism, all of which are grossly modulated by anti- and prooxidant signals. Using a human skin cell model, a transient phosphorylation and nuclear translocation of p53, preceded by the phosphorylation of upstream serine- (ATM) and serine/threonine-protein kinase (ATR), was detected after CAP treatment. Results indicate that ATM acts as a direct redox sensor without relevant contribution of phosphorylation of the histone A2X, a marker of DNA damage. Downstream events are the activation of checkpoint kinases Chk1/2 and several mitogen-activated (MAP) kinases. Subsequently, the expression of MAP kinase signaling effectors (e.g., heat shock protein Hsp27), epithelium derived growth factors, and cytokines (Interleukins 6 + 8) was increased. A number of p53 downstream effectors pointed at a decrease of cell growth due to DNA repair processes. In summary, CAP treatment led to an activation of cell repair and defense mechanisms including a modulation of paracrine inflammatory signals emphasizing the role of prooxidant species in CAP-related cell signaling.

Increased Prevalence of Type 2 Diabetes-Related Complications in Combined Type 2 Diabetes and Sickle Cell Trait

OBJECTIVE

The prevalence of type 2 diabetes (T2D) is rapidly increasing in sub-Saharan Africa, where sickle cell trait (SCT) is also frequent. Although SCT is generally considered a benign condition, evidence suggests that SCT could exaggerate vascular dysfunction in T2D. However, it remains unclear whether SCT could increase the risk of the development of T2D complications. Therefore, this study was conducted to determine whether T2D complications were more prevalent among Senegalese individuals with SCT and T2D than among those with T2D only.

RESEARCH DESIGN AND METHODS

Rates of hypertension, retinopathy, peripheral neuropathy, peripheral artery disease, and impaired renal function as well as arterial stiffness, blood rheology, and concentrations of plasma advanced glycation end products (AGEs) and cytokines were compared between groups of Senegalese individuals with combined SCT and T2D (T2D-SCT) (n = 60), T2D (n = 52), SCT (n = 53), and neither T2D nor SCT (control) (n = 56). Human aortic endothelial cell (HAEC) expression of inflammatory and adhesion factors was measured after treatment with tumor necrosis factor-α and subjects' plasma. Effects of AGE inhibition or tiron on HAEC expression of E-selectin were measured.

RESULTS

Retinopathy, hypertension, and reduced renal function were more prevalent, and arterial stiffness, blood viscosity at high shear rates, and thixotropic index were higher, in the SCT group compared with the other groups. Multivariable analysis showed that plasma AGE concentration was significantly associated with arterial stiffness. E-selectin expression was elevated in HAECs treated with T2D-SCT plasma compared with the other groups, but AGE inhibition reversed this.

CONCLUSIONS

SCT could potentially augment the risk of the development of T2D-related complications, including retinopathy, nephropathy, and hypertension.

Attenuation of antimalarial agent hydroxychloroquine on TNF-α-induced endothelial inflammation

OBJECTIVE

Hydroxychloroquine (HCQ) is an antimalarial drug that is widely used in the treatment of some autoimmune diseases. In the present study, we explore the role of HCQ in regulating endothelial inflammation and its underlying mechanism.

METHODS

Human umbilical vein endothelial cells (HUVECs) were isolated from fresh umbilical cords. Protein expression was measured by Western blot or immunofluorescence staining. Endothelial adhesion ability was determined by leukocyte-endothelial monolayer adhesion assay. Transwell assay was used to measure the transendothelial-migration of PBMCs.

RESULTS

TNF-α-induced endothelial-leukocyte adhesion and the leukocyte transmigration were profoundly reduced by HCQ treatment. HCQ treatment dramatically inhibited the expression of TNF-α-induced endothelial ICAM-1 and VCAM-1. Furthermore, treatment with HCQ prevented the TNF-α-induced translocation of NF-κB p65 into the nucleus and the phosphorylation of the p65 subunit in HUVECs. HCQ inhibited the expression of phosphorylated p38 and JNK protein but not ERK. Treatment with NF-κB, p38 and JNK inhibitor could also reduce TNF-α-induced endothelial-leukocyte adhesion and the endothelial expression of ICAM-1 and VCAM-1. HCQ administration also suppressed TNF-α induced lung injury in mice by reducing neutrophil infiltration in pulmonary interstitial tissue.

CONCLUSIONS

This work shows the inhibitory effect of HCQ on endothelial inflammatory response through, at least in part, blocking NF-κB, p38 and JNK pathways. Our findings suggest that HCQ may be a promising approach for the treatment of inflammatory vascular disease beyond its immunomodulatory actions.

Lipopolysaccharide Downregulates Kruppel-Like Factor 2 (KLF2) via Inducing DNMT1-Mediated Hypermethylation in Endothelial Cells

KLF2 plays a protective role in antiinflammation and endothelial function, and can be regulated by promoter methylation alteration. Lipopolysaccharide (LPS) is a mediator of inflammatory responses, which causes epigenetic change of certain genes in host cells. We thus aimed to determine whether LPS could control the KLF2 expression by inducing methylation in promoter region. DNA methylation of 16 CpG sites within KLF2 promoter region was detected by bisulfite sequencing PCR. Results showed that methylation at 12 CpG sites were significantly increased in HUVECs after exposure to LPS among the total 16 sites, and the average level was increased by 57%. The KLF2 expressions assessed by reverse transcription quantitative real-time PCR and Western blot were significantly downregulated compared that without LPS simulation. Moreover, both messenger RNA and protein levels of KLF2 in HUVEC co-treated with LPS and DNA methyltransferase (DNMT) 1 small interfering RNA were dramatically higher than that treated with LPS only. Similar result was obtained when the cells were incubated in combination with LPS and 5-aza-2'-deoxycytidine (AZA), suggesting that the reduction of KLF2 expression induced by LPS can be reversed by DNMT1 inhibition. Finally, the presence of AZA changed the expression of genes that depends on KLF2 in LPS-stimulated HUVECs, which downregulated the E-selectin and VCAM and increased the eNOS and thrombomodulin expression. Our data demonstrated that LPS exposure resulted in hypermethylation in KLF2 promoter in HUVECs, which subsequently led to downregulation of the KLF2 expression. The study suggested that epigenetic alteration is involved in LPS-induced inflammatory response and provided a new insight into atherogenesis.

p38 activation induces production of miR-146a and miR-31 to repress E-selectin expression and inhibit transendothelial migration of colon cancer cells

Extravasation of circulating cancer cells determines their metastatic potential. This process is initiated by the adhesion of cancer cells to vascular endothelial cells through specific interactions between endothelial adhesion receptors such as E-selectin and their ligands on cancer cells. In the present study, we show that miR-146a and miR-181b impede the expression of E-selectin by repressing the activity of its transcription factor NF-κB, thereby impairing the metastatic potentials of colon cancer cells by decreasing their adhesion to, and migration through, the endothelium. Among the two microRNAs, only miR-146a is activated by IL-1β, through the activation of p38, ERK and JNK MAP kinases, as well as their downstream transcription factors GATA2, c-Fos and c-Jun. Inhibiting p38 MAP kinase increases NF-κB activity, at least partially via miR-146a. Inhibiting p38 also increases the expression of E-selectin at the post-transcriptional level via decreasing miR-31, which targets E-selectin mRNA and also depends on p38 for its expression. In response to IL-1β, p38 MAP kinase hence represses the expression of E-selectin at the transcriptional and the post-transcriptional levels, via miR-146a and miR-31, respectively. These results highlight novel mechanisms by which p38 downregulates the expression of E-selectin through different microRNAs following inflammatory stimuli associated to cancer progression.

EphrinB-mediated reverse signalling controls junctional integrity and pro-inflammatory differentiation of endothelial cells

The EphB/ephrinB receptor-ligand system is pivotal for the development of the embryonic vasculature and for angiogenesis in the adult organism. We observed that (i) the expression of ephrinB2 and ephrinB1 is up-regulated in capillaries during inflammation, that (ii) these ligands are localised on the luminal endothelial surface, and that (iii) they interact with the ephrinB-receptor EphB2 on monocyte/macrophages. This study delineates the impact of ephrinB-mediated reverse signalling on the integrity and proinflammatory differentiation of the endothelium. To this end, in vitro analyses with human cultured endothelial cells reveal that knockdown of ephrinB2 or ephrinB1 impairs monocyte transmigration through the endothelium. While ephrinB2 but not ephrinB1 interacts with PECAM-1 (CD31) in this context, reverse signalling by ephrinB1 but not ephrinB2 elicits a c-Jun N-terminal kinase (JNK)-dependent up-regulation of E-selectin expression. Furthermore, treatment of endothelial cells with soluble EphB2 receptor bodies or EphB2-overexpressing mouse myeloma cells links ephrinB2 to PECAM-1 and induces its Src-dependent phosphorylation while diminishing Src homology phosphotyrosyl phosphatase-2 (SHP-2) activity and increasing endothelial cell permeability. We conclude that extravasation of EphB2 positive leukocyte populations is facilitated by lowering the integrity of endothelial cell junctions and enhancing the pro-inflammatory phenotype of the endothelium through activation of ephrinB ligands.

NFκB transcription factor (p65) immunohistochemistry in leprosy dermal microvasculature

Leprosy caused by Mycobacterium leprae is characterized by a spectrum of clinical manifestations that are determined by the predominant immunological profile of the host. The recruitment of leukocytes to the sites of injury can influence the development of these profiles. Cell adhesion molecules such as ICAM-1, VCAM-1 and CD62E participate in this process and their expression is regulated by transcriptions factors such as NFκB. To correlate the expression of cell adhesion molecules and NFκB (p65) in leprosy lesions, 30 skin biopsies of patients with leprosy [16 with the tuberculoid (TT) or borderline tuberculoid (BT) forms and 14 with the lepromatous (LL) or borderline lepromatous (BL) forms] were analyzed by immunohistochemistry. A larger mean number of cells expressing VCAM-1 (BT/TT: 18.28 ± 1.4; BL/LL: 10.67 ± 1.2; p = 0.0002), ICAM-1 (BT/TT: 9.92 ± 1.1; BL/LL: 5.87 ± 1.0; p = 0.0084) and CD62E (BT/TT: 13.0 ± 1.5; BL/LL: 2.58 ± 0.3; p = 0.0001) were observed in BT and TT lesions. The mean number of cells expressing NFκB was similar in the two clinical forms (BT/TT: 2.21 ± 2.7; BL/LL: 2.35 ± 3.1;p = 0.9285). No significant correlation was observed between expression of the transcription factor and adhesion molecules analyzed. The synthesis of ICAM-1, VCAM-1 and CD62E depends on the activation of NFκB, which acts synergistically with other transcription factors. Adequate activation of intracellular signaling pathways results in the production of endothelial adhesion molecules, contributing to the recruitment of cells to the site of injury and thus eliciting an effective inflammatory response in the elimination of the bacillus.

Effect of etoricoxib on experimental oxidative testicular ischemia-reperfusion damage in rats induced with torsion-detorsion

Etoricoxib features antioxidant and anti-inflammatory properties concomitantly, suggesting that it may be beneficial in testicular ischemia reperfusion (I/R) damage. Our aim is to investigate the effects of etoricoxib on testicular I/R damage induced with torsion-detorsion (TD). The etoricoxib + torsion-detorsion (ETD) groups of animals were given etoricoxib in 50 and 100 mg/kg of body weight (ETD-50 and ETD-100), while the testes torsion-detorsion (TTD) and sham operation rat group (SOG) animals were given single oral doses of distilled water as a solvent. TTD, ETD-50 and ETD-100 groups were subjected to 720° degrees torsion for four hours, and detorsion for four hours. The SOG group was not subjected to this procedure. Biochemical, gene expression and histopathological analyses were carried out on the testicular tissues. The levels of malondialdehyde (MDA), myeloperoxidase (MPO), interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) were significantly higher, and the levels of total glutathione (tGSH) and glutathione reductase (GSHRd) were significantly lower in the TTD group, compared to the ETD-50, ETD-100 and SOG groups. Etoricoxib at a dose of 100 mg/kg better prevented I/R damage than the 50 mg/kg dose. Etoricoxib may be useful in clinical practice in the reduction of I/R damage on testes caused by torsion-detorsion.

ATF2, a paradigm of the multifaceted regulation of transcription factors in biology and disease

Stringent transcriptional regulation is crucial for normal cellular biology and organismal development. Perturbations in the proper regulation of transcription factors can result in numerous pathologies, including cancer. Thus, understanding how transcription factors are regulated and how they are dysregulated in disease states is key to the therapeutic targeting of these factors and/or the pathways that they regulate. Activating transcription factor 2 (ATF2) has been studied in a number of developmental and pathological conditions. Recent findings have shed light on the transcriptional, post-transcriptional, and post-translational regulatory mechanisms that influence ATF2 function, and thus, the transcriptional programs coordinated by ATF2. Given our current knowledge of its multiple levels of regulation and function, ATF2 represents a paradigm for the mechanistic complexity that can regulate transcription factor function. Thus, increasing our understanding of the regulation and function of ATF2 will provide insights into fundamental regulatory mechanisms that influence how cells integrate extracellular and intracellular signals into a genomic response through transcription factors. Characterization of ATF2 dysfunction in the context of pathological conditions, particularly in cancer biology and response to therapy, will be important in understanding how pathways controlled by ATF2 or other transcription factors might be therapeutically exploited. In this review, we provide an overview of the currently known upstream regulators and downstream targets of ATF2.

Ischemic preconditioning modulates ROS to confer protection in liver ischemia and reperfusion

Ischemia reperfusion (IR) injury is a significant cause of morbidity and mortality in liver transplantation. When oxygen is reintroduced to the liver graft it initiates a cascade of molecular reactions leading to the release of reactive oxygen species (ROS) and pro-inflammatory cytokines. These soluble mediators propagate a sterile immune response to cause significant tissue damage. Ischemic preconditioning (IPC) is one method that reduces hepatocellular injury by altering the immune response and inhibiting the production of ROS. Studies quantifying the effects of IPC in humans have demonstrated an improved liver enzyme panel in patients receiving grafts pretreated with IPC as compared to patients receiving the standard of care. In our review, we explore current literature in the field in order to describe the mechanism through which IPC regulates the production of ROS and improves IR injury.

The suppression of bromodomain and extra-terminal domain inhibits vascular inflammation by blocking NF-κB and MAPK activation

BACKGROUND AND PURPOSE

There is increasing evidence indicating that bromodomain and extra-terminal domain (BET) proteins play a critical role in the regulation of immune and inflammatory responses; however, their contribution to vascular inflammation has not yet been elucidated. In this study, we investigated the effect of inhibiting BET bromodomain on vascular inflammation and the underlying mechanisms.

EXPERIMENTAL APPROACH

HUVECs were isolated from fresh umbilical cords. JQ1, a specific BET bromodomain inhibitor, and Brd shRNA were used to evaluate the regulation of the BET proteins in vascular inflammation. Leukocyte adhesion to HUVECs was measure by an adhesion assay. Western blot or immunohistochemical analysis was used to detect the protein expression. Real-time PCR was used to evaluate mRNA expression. Leukocyte accumulation in vivo was determined by an acute lung inflammation model.

KEY RESULTS

BET bromodomain inhibition suppressed the expression of adhesion molecules induced by TNF-α- or LPS, including ICAM-1, VCAM-1 and E-selectin, and inhibited leukocyte adhesion to activated HUVEC monolayers. Treatment with JQ1 also attenuated the LPS-induced accumulation of leukocytes and expression of endothelial adhesion molecules in the acute lung inflammation model in vivo. Furthermore, BET bromodomain inhibition reduced the activity of p38 and JNK MAPKs and NF-κB in TNF-α-stimulated HUVECs. TNF-α-induced NF-κB activation was also blocked by inhibitors of p38 (SB203580) or JNK (SP600125).

CONCLUSIONS AND IMPLICATIONS

BET bromodomain is important for regulating endothelial inflammation. Strategies targeting endothelial BET bromodomain may provide a new therapeutic approach for controlling inflammatory-related diseases.

S-nitrosocaptopril interrupts adhesion of cancer cells to vascular endothelium by suppressing cell adhesion molecules via inhibition of the NF-кB and JAK/STAT signal pathways in endothelial cells

Inflammatory cytokines can induce the expression of cell adhesion molecules (CAMs) in endothelial cells. The induction may play an important role in attracting circulating tumor cells (CTCs) to endothelial cells. S-nitrosocaptopril (CapNO) is known to produce vasorelaxation and interfere the hetero-adhesion of CTCs to vascular endothelium via down-regulating the expression of CAMs. To elucidate the mechanisms underlying the inhibition of CapNO on CAMs, in this study, we examined the relationship between cytokines and CAMs expression and investigated the effects of CapNO on cytokine-induced NF-кB and JAK/STAT signal pathways. The activation of CAMs by cytokines was dependent on concentrations and reaction time of cytokines, and the combination of cytokines could produce a strong synergistic effect. IL-1β induced the expression of CAMs on endothelial cells by activating NF-кB and JAK/STAT pathways. CapNO inhibited IL-1β-stimulated NF-кB pathway by down-regulating IKK-α and inducing IкB-α directly. CapNO also inhibited JAK/STAT pathway by inhibiting JAK2 and STAT3 expressions. These effects bring about down-regulating CAMs expression on endothelial cells. These results suggest that CapNO may interrupt adhesion of cancer cells to endothelium by suppressing CAMs via inhibiting the NF-кB and JAK/STAT pathways in endothelial cells.

Leukocytes Crossing the Endothelium: A Matter of Communication

Leukocytes cross the endothelial vessel wall in a process called transendothelial migration (TEM). The purpose of leukocyte TEM is to clear the causing agents of inflammation in underlying tissues, for example, bacteria and viruses. During TEM, endothelial cells initiate signals that attract and guide leukocytes to sites of tissue damage. Leukocytes react by attaching to these sites and signal their readiness to move back to endothelial cells. Endothelial cells in turn respond by facilitating the passage of leukocytes while retaining overall integrity. In this review, we present recent findings in the field and we have endeavored to synthesize a coherent picture of the intricate interplay between endothelial cells and leukocytes during TEM.

Endothelial protein kinase MAP4K4 promotes vascular inflammation and atherosclerosis

Signalling pathways that control endothelial cell (EC) permeability, leukocyte adhesion and inflammation are pivotal for atherosclerosis initiation and progression. Here we demonstrate that the Sterile-20-like mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), which has been implicated in inflammation, is abundantly expressed in ECs and in atherosclerotic plaques from mice and humans. On the basis of endothelial-specific MAP4K4 gene silencing and gene ablation experiments in Apoe(-/-) mice, we show that MAP4K4 in ECs markedly promotes Western diet-induced aortic macrophage accumulation and atherosclerotic plaque development. Treatment of Apoe(-/-) and Ldlr(-/-) mice with a selective small-molecule MAP4K4 inhibitor also markedly reduces atherosclerotic lesion area. MAP4K4 silencing in cultured ECs attenuates cell surface adhesion molecule expression while reducing nuclear localization and activity of NFκB, which is critical for promoting EC activation and atherosclerosis. Taken together, these results reveal that MAP4K4 is a key signalling node that promotes immune cell recruitment in atherosclerosis.

Crossing the Vascular Wall: Common and Unique Mechanisms Exploited by Different Leukocyte Subsets during Extravasation

Leukocyte extravasation is one of the essential and first steps during the initiation of inflammation. Therefore, a better understanding of the key molecules that regulate this process may help to develop novel therapeutics for treatment of inflammation-based diseases such as atherosclerosis or rheumatoid arthritis. The endothelial adhesion molecules ICAM-1 and VCAM-1 are known as the central mediators of leukocyte adhesion to and transmigration across the endothelium. Engagement of these molecules by their leukocyte integrin receptors initiates the activation of several signaling pathways within both leukocytes and endothelium. Several of such events have been described to occur during transendothelial migration of all leukocyte subsets, whereas other mechanisms are known only for a single leukocyte subset. Here, we summarize current knowledge on regulatory mechanisms of leukocyte extravasation from a leukocyte and endothelial point of view, respectively. Specifically, we will focus on highlighting common and unique mechanisms that specific leukocyte subsets exploit to succeed in crossing endothelial monolayers.

A critical role for ATF2 transcription factor in the regulation of E-selectin expression in response to non-endotoxin components of Neisseria meningitidis

Vascular injury is a serious complication of sepsis due to the gram‐negative bacterium Neisseria meningitidis. One of the critical early steps in initiating this injury is via the interaction of leucocytes, particularly neutrophils, with adhesion molecules expressed on inflamed endothelium. We have previously demonstrated that both lipopolysaccharide (LPS) and non‐LPS components of meningococci can induce very high levels of expression of the vascular endothelial cell adhesion molecule E‐selectin, which is critical for early tethering and capture of neutrophils onto endothelium under flow. Using an LPS‐deficient strain of meningococcus, we showed that very high levels of expression can be induced in primary endothelial cells, even in the context of weak activation of the major host signal transduction factor [nuclear factor‐κB (NF‐κB)]. In this study, we show that the particular propensity for N. meningitidis to induce high levels of expression is regulated at a transcriptional level, and demonstrate a significant role for phosphorylation of the ATF2 transcription factor, likely via mitogen‐activated protein (MAP) kinases, on the activity of the E‐selectin promoter. Furthermore, inhibition of E‐selectin expression in response to the lpxA− strain by a p38 inhibitor indicates a significant role of a p38‐dependent MAPK signalling pathway in ATF2 activation. Collectively, these data highlight the role that LPS and other bacterial components have in modulating endothelial function and their involvement in the pathogenesis of meningococcal sepsis. Better understanding of these multiple mechanisms induced by complex stimuli such as bacteria, and the specific inflammatory pathways they activate, may lead to improved, focused interventions in both meningococcal and potentially bacterial sepsis more generally.

Effects of oxidized phospholipids on gene expression in RAW 264.7 macrophages: a microarray study

Oxidized phospholipids (oxPLs) are components of oxidized LDL (oxLDL). It is known that oxLDL activates expression of a series of atherogenic genes and their oxPLs contribute to their biological activities. In this study we present the effects of 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC) and 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) on gene expression in RAW 264.7 macrophages using cDNA microarrays. PGPC affected the regulation of 146 genes, whereas POVPC showed only very minor effects. PGPC preferentially influenced expression of genes related to cell death, angiogenesis, cholesterol efflux, procoagulant mechanisms, atherogenesis, inflammation, and cell cycle. Many of these effects are known from studies with oxLDL or oxidized 1-hexadecanoyl-2-eicosatetra-5′,8′,11′,14′-enoyl-sn-glycero-3-phosphocholine (oxPAPC), containing PGPC in addition to other oxPL species. It is known that POVPC efficiently reacts with proteins by Schiff base formation, whereas PGPC only physically interacts with its biological targets. POVPC seems to affect cell physiology to a great extent on the protein level, whereas PGPC gives rise to both the modulation of protein function and regulation on the transcriptional level.

Biophysiochemical properties of endothelial cells cultured on bio-inspired collagen films

Background

In this study, we investigated the effect of the extracellular matrix on endothelial dysfunction by careful observation of human umbilical vein endothelial cells (HUVECs) cultured on denatured collagen film.

Results

HUVECs on denatured collagen film showed relatively high surface roughness compared with normal HUVECs. The expression levels of MMP-1, MMP-2 and CD146 increased in the ECs on denatured collagen film. In addition, we examined the accumulation of fluorescent beads on HUVEC layers subjected to circulatory flow. The number of accumulated fluorescent beads increased on the disorganized HUVEC layers.

Conclusions

The proposed in vitro study using bio-inspired collagen films could potentially be used in the size- and ligand-based design of drugs to treat endothelial dysfunction caused by circulatory vascular diseases.

c-Jun N-Terminal Kinases Mediate a Wide Range of Targets in the Metastatic Cascade

Disseminated cancer cells rely on intricate interactions among diverse cell types in the tumor-associated stroma, vasculature, and immune system for survival and growth. Ubiquitous expression of c-Jun N-terminal kinase (jnk) genes in various cell types permits their control of metastasis. In early stages of metastasis, JNKs affect tumor-associated inflammation and angiogenesis as well as tumor cell migration and intravasation. Within the tumor stroma, JNKs are essential for the release of growth factors that promote epithelial-to-mesenchymal transition (EMT) in tumor cells. JNK3, the least ubiquitous isoform, facilitates angiogenesis by increasing endothelial cell migration. Importantly, JNK expression in tumor cells integrates stromal signals to promote tumor cell invasion. However, JNK isoforms differentially regulate migration toward the endothelial barrier. Once tumor cells enter the bloodstream, JNKs increase circulating tumor cell (CTC) survival and homing to tissues. By promoting fibrosis, JNKs improve CTC attachment to the endothelium. Once anchored, JNKs stimulate EMT to facilitate tumor cell extravasation and enhance the secretion of endothelial barrier disrupters. Tumor cells attract barrier-disrupting macrophages by JNK-dependent transcription of macrophage chemoattractant molecules. In the secondary tissue, JNKs are instrumental in the premetastatic niche and stimulate tumor cell proliferation. JNK expression in cancer cells stimulates tissue-remodeling macrophages to improve tumor colonization. However, in T-cells, JNKs alter cytokine production that increases tumor surveillance and inhibits the recruitment of tissue-remodeling macrophages. Therapeutically targeting JNKs for metastatic disease is attractive considering their promotion of metastasis; however, specific JNK tools are needed to determine their definitive actions within the context of the entire metastatic cascade.

Sirtuin 1 stabilization by HuR represses TNF-α- and glucose-induced E-selectin release and endothelial cell adhesiveness in vitro: relevance to human metabolic syndrome

Overexpression of SIRT1 and of HuR protein, a SIRT1 mRNA stabilizer, prevents TNF-α- and high-glucose-induced E-selectin release and cell adhesion. As a result, SIRT1 stabilization by HuR is reduced, SIRT1 expression is lower, and plasma E-selectins are increased in the patients with the metabolic syndrome.

Cell density impacts epigenetic regulation of cytokine-induced E-selectin gene expression in vascular endothelium

Growing evidence suggests that the phenotype of endothelial cells during angiogenesis differs from that of quiescent endothelial cells, although little is known regarding the difference in the susceptibility to inflammation between both the conditions. Here, we assessed the inflammatory response in sparse and confluent endothelial cell monolayers. To obtain sparse and confluent monolayers, human umbilical vein endothelial cells were seeded at a density of 7.3 × 10(3) cells/cm(2) and 29.2 × 10(3) cells/cm(2), respectively, followed by culturing for 36 h and stimulation with tumor necrosis factor α. The levels of tumor necrosis factor α-induced E-selectin protein and mRNA expression were higher in the confluent monolayer than in the sparse monolayer. The phosphorylation of c-jun N-terminal kinase and p38 mitogen-activated protein kinase or nuclear factor-κB activation was not involved in this phenomenon. A chromatin immunoprecipitation assay of the E-selectin promoter using an anti-acetyl-histone H3 antibody showed that the E-selectin promoter was highly and specifically acetylated in the confluent monolayer after tumor necrosis factor α activation. Furthermore, chromatin accessibility real-time PCR showed that the chromatin accessibility at the E-selectin promoter was higher in the confluent monolayer than in the sparse monolayer. Our data suggest that the inflammatory response may change during blood vessel maturation via epigenetic mechanisms that affect the accessibility of chromatin.

Paeoniflorin suppresses vascular damage and the expression of E-selectin and ICAM-1 in a mouse model of cutaneous Arthus reaction

Paeoniflorin (PF) extracted from the root of Paeonia lactiflora pall, displays anti-inflammation properties in several animal models. Adhesion molecules are important for the recruitment of leucocyte to the vessel wall and involved in the pathogenesis of various autoimmune and inflammatory diseases. Herein, we investigate the effects of PF on adhesion molecule expression in a mouse model of cutaneous Arthus reaction and cultured human dermal microvascular endothelial cells (HDMECs). We showed that PF significantly ameliorated the immune complex (IC) induced vascular damage, leucocyte infiltrates and adhesion molecules expression. Furthermore, PF markedly blocked tumor necrosis factor-α (TNF-α)-induced E-selectin and intercellular adhesion molecule-1 (ICAM-1) expression in HDMECs at both mRNA and protein levels. PF also suppressed TNF-α-induced adhesion of polymorphonuclear leucocytes (PMNs) to HDMECs. Finally, western blot data revealed that PF can inhibit the phosphorylation of p38, JNK in TNF-α-treated HDMECs. These data suggest that PF, as an anti-inflammatory agent, can downregulate adhesion molecules expression. PF may be a candidate medicine for the treatment of IC-induced inflammatory response.

Lignans 7-hydroxymatairesinol and 7-hydroxymatairesinol 2 exhibit anti-inflammatory activity in human aortic endothelial cells

SCOPE

In the present study, we evaluated the anti-inflammatory properties of several plant lignans most commonly distributed in foods. 7-Hydroxymatairesinol (HMR) and its major isomer 7-hydroxymatairesinol 2 (HMR2), lariciresinol, secoisolariciresinol, and pinoresinol, isolated from Norway spruce knots were examined.

METHODS AND RESULTS

We investigated the anti-inflammatory effects of lignans on tumor necrosis factor-α-treated human aortic endothelial cells by measuring the expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 by cell ELISA and the adhesion of U937 monocytes to activated endothelial cells using a cell adhesion assay. Among the lignans studied, HMR and HMR2 significantly reduced intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels as well as the adhesion of U937 to endothelial cells. To further characterize the molecular mechanisms involved in this regulation, the effect of HMR and HMR2 on nuclear factor-κB, SAPK/c-Jun NH2-terminal kinase and extracellular signal regulated kinase phosphorylation was assessed.

CONCLUSION

Our results demonstrated that the lignans HMR and HMR2, dominant in cereals such as in wheat, triticale, oat, barley, millet, corn bran, and in amaranth whole grain, exhibit strong anti-inflammatory properties in endothelial cells, at least in part, through attenuation of nuclear factor-κB and extracellular signal regulated kinase phosphorylation.

TNFα signals via p66(Shc) to induce E-Selectin, promote leukocyte transmigration and enhance permeability in human endothelial cells

Endothelial cells participate in inflammatory events leading to atherogenesis by regulating endothelial cell permeability via the expression of VE-Cadherin and β-catenin and leukocyte recruitment via the expression of E-Selectins and other adhesion molecules. The protein p66^Shc acts as a sensor/inducer of oxidative stress and may promote vascular dysfunction. The objective of this study was to investigate the role of p66^Shc in tumor necrosis factor TNFα-induced E-Selectin expression and function in human umbilical vein endothelial cells (HUVEC). Exposure of HUVEC to 50 ng/ml TNFα resulted in increased leukocyte transmigration through the endothelial monolayer and E-Selectin expression, in association with augmented phosphorylation of both p66^Shc on Ser³⁶ and the stress kinase c-Jun NH₂-terminal protein kinase (JNK)-1/2, and higher intracellular reactive oxygen species (ROS) levels. Overexpression of p66^Shc in HUVEC resulted in enhanced p66^Shc phosphorylation on Ser³⁶, increased ROS and E-Selectin levels, and amplified endothelial cell permeability and leukocyte transmigration through the HUVEC monolayer. Conversely, overexpression of a phosphorylation-defective p66^Shc protein, in which Ser³⁶ was replaced by Ala, did not augment ROS and E-Selectin levels, nor modify cell permeability or leukocyte transmigration beyond those found in wild-type cells. Moreover, siRNA-mediated silencing of p66^Shc resulted in marked reduction of E-Selectin expression and leukocyte transmigration. In conclusion, p66^Shc acts as a novel intermediate in the TNFα pathway mediating endothelial dysfunction, and its action requires JNK-dependent phosphorylation of p66^Shc on Ser³⁶.

Cytoprotective signaling and gene expression in endothelial cells and macrophages-lessons for atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the medium and large arteries driven in large part by the accumulation of oxidized low-density lipoproteins and other debris at sites rendered susceptible because of the geometry of the arterial tree. As lesions develop, they acquire a pathologic microcirculation that perpetuates lesion progression, both by providing a means for further monocyte and T-lymphocyte recruitment into the arterial wall and by the physical and chemical stresses caused by micro-hemorrhage. This review summarizes work performed in our department investigating the roles of signaling pathways, alone and in combination, that lead to specific programs of gene expression in the atherosclerotic environment. Focusing particularly on cytoprotective responses that might be enhanced therapeutically, the work has encompassed the anti-inflammatory effects of arterial laminar shear stress, mechanisms of induction of membrane inhibitors that prevent complement-mediated injury, homeostatic macrophage responses to hemorrhage, and the transcriptional mechanisms that control the stability, survival, and quiescence of endothelial monolayers. Lastly, while the field has been dominated by investigation into the mechanisms of DNA transcription, we consider the importance of parallel post-transcriptional regulatory mechanisms for fine-tuning functional gene expression repertoires.

Release of nonmuscle myosin II from the cytosolic domain of tumor necrosis factor receptor 2 is required for target gene expression

Tumor necrosis factor-α (TNF-α) elicits its biological activities through activation of TNF receptor 1 (TNFR1, also known as p55) and TNFR2 (also known as p75). The activities of both receptors are required for the TNF-α-induced proinflammatory response. The adaptor protein TNFR-associated factor 2 (TRAF2) is critical for either p55- or p75-mediated activation of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, as well as for target gene expression. We identified nonmuscle myosin II (myosin) as a binding partner of p75. TNF-α-dependent signaling by p75 and induction of target gene expression persisted substantially longer in cells deficient in myosin regulatory light chain (MRLC; a component of myosin) than in cells replete in myosin. In resting endothelial cells, myosin was bound constitutively to the intracellular region of p75, a region that overlaps with the TRAF2-binding domain, and TNF-α caused the rapid dissociation of myosin from p75. At early time points after exposure to TNF-α, p75 activated Rho-associated kinase 1 (ROCK1). Inhibition of ROCK1 activity blocked TNF-α-dependent phosphorylation of MRLC and the dissociation of myosin from p75. ROCK1-dependent release of myosin was necessary for the TNF-α-dependent recruitment of TRAF2 to p75 and for p75-specific activation of NF-κB and MAPK signaling. Thus, our findings have revealed a previously uncharacterized, noncanonical regulatory function of myosin in cytokine signaling.

Hyperbaric oxygen therapy in rats attenuates ischemia-reperfusion testicular injury through blockade of oxidative stress, suppression of inflammation, and reduction of nitric oxide formation

OBJECTIVE

To evaluate the therapeutic utility of hyperbaric oxygen (HBO) therapy on testicular ischemia/reperfusion (I/R) injury and elucidate the underlying molecular mechanism, we tested whether HBO therapy provided rescue of the testes after torsion in rats.

METHODS

Sprague-Dawley rats were randomly divided into 4 groups: control group, control plus HBO therapy, I/R group, and I/R plus HBO therapy. The I/R model was induced by torsion of the right testis.

RESULTS

I/R in the testis resulted in disrupted seminiferous tubules, germ cell-specific apoptosis, followed by a marked reduction in testis weight and daily sperm production. HBO therapy preserved seminiferous tubules, suppressed apoptosis, and prevented testicular atrophy in I/R testes. HBO therapy abated oxidative stress in I/R testes, marked by reduced malondialdehyde formation, enhanced activities of superoxide dismutase and heme oxygenase 1 (HO-1), and decreased activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and xanthine oxidase. HBO therapy resulted in a reduction of myeloperoxidase (MPO) activity in I/R testes, a marker of neutrophil recruitment. HBO therapy suppressed inflammation in I/R testes, marked by reduced messenger RNA (mRNA) levels of tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), and CD44. Furthermore, HBO therapy suppressed the activation of nuclear factor kappa B (NFκB), p38, and c-JUN-N-terminal kinase (JNK) signaling pathways in I/R testes. In addition, HBO therapy reduced nitric oxide formation in I/R testes through suppression of inducible nitric oxide synthase and dimethylarginine dimethylaminohydrolase.

CONCLUSION

HBO therapy in rats attenuated I/R-induced testicular injury, possibly through abating oxidative stress, suppressing inflammation, and reducing nitric oxide formation.

Ethanol extract of Adiantum capillus-veneris L. suppresses the production of inflammatory mediators by inhibiting NF-κB activation

ETHNOPHARMACOLOGICAL RELEVANCE

Adiantum capillus-veneris L. is a wildly distributed plant species and has been extensively used in south of China as traditional folk medicine for the treatment of inflammatory diseases.

AIM OF THE STUDY

To investigate the anti-inflammatory effect of ethanolic extracts of Adiantum capillus-veneris L. and the involvement of NF-κB signaling in the regulation of inflammation.

MATERIALS AND METHODS

The plant ethanolic extracts were initially tested against lipopolysaccharide (LPS)-induced prostaglandin E2 (PGE2) production in RAW264.7 mouse macrophages, and interleukin 6 (IL-6) and tumor necrosis factor (TNF) production in human U937 monocytes. The effect of the plant extracts on the transcription factor nuclear factor kappa B (NF-κB) pathway was evaluated in TNF-α stimulated HepG2 cells by luciferase gene reporter assay and Western blotting at the transcriptional and translational levels. Subsequently, the inhibition of NF-κB downstream gene expression (IL-8 and ICAM-1) by the plant extracts was assessed via quantitative real time polymerase chain reaction (qPCR). Lastly, the anti-inflammatory activities of the plant extracts in vivo were evaluated by testing spleen index and NF-κB related protein expression in LPS-stimulated CD1 mice.

RESULTS

The plant ethanolic extracts effectively suppressed PGE2, IL-6 and TNF release with an IC50 less than 50 μg/ml. Moreover, luciferase expression could be specifically blocked in HepG2 cells, not in HEK293 cells, showing that the plant extracts displayed a cell-specific pattern on NF-κB gene transcription. The assayed biological activity also depended on the order of adding TNF-α and the plant extracts because the plant extracts could only block the NF-κB activation if added earlier but were unable to stop the signal when added after TNF-α. However, the plant extracts did not exert any effect on ubiquitination which regulates several steps in the NF-κB pathway. Additionally, the plant extracts down-regulated phosphorylation of IKKα/β at S176/180, p38 at T180/Y182 and p65 at S536, but not p65 at S276. This was confirmed by their ability to selectively abrogate the induction of IL-8 transcription, whereas the ICAM-1 gene, which is not transcribed selectively by an NF-κB complex containing a form of p65 phosphorylated on Ser536, did not change. Finally, the plant extracts at 200 μg/mg could normalize the LPS-induced elevation of spleen index as well as NF-κB and p38 activations in CD1 mice.

CONCLUSION

The present studies presents the potential utilization of this plant extracts, as a natural resources for the development of an anti-inflammatory medicine.