A novel cell adhesion inhibitor, K-7174, reduces the endothelial VCAM-1 induction by inflammatory cytokines, acting through the regulation of GATA

Increased Expression of VCAM1 on Brain Endothelial Cells Drives Blood-Brain Barrier Impairment Following Chronic Cerebral Hypoperfusion

Chronic cerebral hypoperfusion (CCH)-triggered blood-brain barrier (BBB) dysfunction is a core pathological change occurring in vascular dementia (VD). Despite the recent advances in the exploration of the structural basis of BBB impairment and the routes of entry of harmful compounds after a BBB leakage, the molecular mechanisms inducing BBB impairment remain largely unknown in terms of VD. Here, we employed a CCH-induced VD model and discovered increased vascular cell adhesion molecule 1 (VCAM1) expression on the brain endothelial cells (ECs). The expression of VCAM1 was directly correlated with the severity of BBB impairment. Moreover, the VCAM1 expression was associated with different regional white matter lesions. Furthermore, a compound that could block VCAM1 activation, K-7174, was also found to alleviate BBB leakage and protect the white matter integrity, whereas pharmacological manipulation of the BBB leakage did not affect the VCAM1 expression. Thus, our results demonstrated that VCAM1 is an important regulator that leads to BBB dysfunction following CCH. Blocking VCAM1-mediated BBB impairment may thus offer a new strategy to treat CCH-related neurodegenerative diseases.

Targeting VCAM-1: a therapeutic opportunity for vascular damage

INTRODUCTION

The vascular cell adhesion molecule (VCAM-1) is a transmembrane sialoglycoprotein detected in activated endothelial and vascular smooth muscle cells involved in the adhesion and transmigration of inflammatory cells into damaged tissue. Widely used as a pro-inflammatory marker, its potential role as a targeting molecule has not been thoroughly explored.

AREAS COVERED

We discuss the current evidence supporting the potential targeting of VCAM-1 in atherosclerosis, diabetes, hypertension and ischemia/reperfusion injury.

EXPERT OPINION

There is emerging evidence that VCAM-1 is more than a biomarker and may be a promising therapeutic target for vascular diseases. While there are neutralizing antibodies that allow preclinical research, the development of pharmacological tools to activate or inhibit this protein are required to thoroughly assess its therapeutic potential.

Procoagulant phenotype induced by oxidized high-density lipoprotein associates with acute kidney injury and death

BACKGROUND

Oxidative stress derived from severe systemic inflammation promotes conversion from high-density lipoprotein HDL to oxidized HDL (oxHDL), which interacts with vascular endothelial cells (ECs). OxHDL acquires procoagulant features playing a role in modulating coagulation, which has been linked with organ failure in ICU patients. However, whether oxHDL elicits a ECs-mediated procoagulant phenotype generating organ failure and death, and the underlying molecular mechanism is not known. Therefore, we studied whether oxHDL-treated rats and high-oxHDL ICU patients exhibit a procoagulant phenotype and its association with kidney injury and mortality and the endothelial underlying molecular mechanism.

METHODS

Human ECs, oxHDL-treated rats and ICU patients were subjected to several cellular and molecular studies, coagulation analyses, kidney injury assessment and mortality determination.

RESULTS

OxHDL-treated ECs showed a procoagulant protein expression reprograming characterized by increased E-/P-selectin and vWF mRNA expression through specific signaling pathways. OxHDL-treated rats exhibited a procoagulant phenotype and modified E-/P-selectin, vWF, TF and t-PA mRNA expression correlating with plasma TF, t-PA and D-dimer. Also, showed increased death events and the relative risk of death, and increased creatinine, urea, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased eGFR, all concordant with kidney injury, correlated with plasma TF, t-PA and D-dimer. ICU patients showed correlation between plasma oxHDL and increased creatinine, cystatin, BUN, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased GFR. Notably, ICU high-oxHDL patients showed decreased survival. Interestingly, altered coagulation factors TF, t-PA and D-dimer correlated with both increased oxHDL levels and kidney injury markers, indicating a connection between these factors.

CONCLUSION

Increased circulating oxHDL generates an endothelial-dependent procoagulant phenotype that associates with acute kidney injury and increased risk of death.

Small molecule compound K-7174 attenuates neuropsychiatric manifestations in lupus-prone mice

The neuropsychiatric manifestations of systemic lupus erythematosus (NPSLE) present significant morbidity and mortality due to frequent non-response or adverse effects of the current clinical drugs. The disruption of the blood-brain barrier (BBB) contributes to inflammatory NPSLE disease progression. K-7174, a highly piperazine-derived compound, inhibits leukocyte adhesion and inflammatory factor expression. The present study aimed to comprehensively assess the treatment effect of neurobehavioral deficits in MRL/lpr mice, a validated neuropsychiatric lupus model. The intraperitoneal injection of K-7174 alleviated lupus-like symptoms and improved cognitive dysfunction in MRL/lpr mice. Also, it significantly attenuated neuronal degeneration and decreased serum albumin deposition in the hippocampus. Furthermore, K-7174 acted directly on the brain microvascular endothelial bEnd.3 cells and reduced the BBB permeability, manifested by inhibiting the activation of brain microvascular endothelial cells and increasing the expression of tight junctions (TJs). Notably, in vitro experiments showed that K-7174 alleviates the decreased ZO1 and Occludin expression in bEnd.3 cells caused by lactate increase, improving cell permeability via the MCT4/NKAP/CREB signaling pathway. These findings suggested that K-7174 mediates the attenuation of NPSLE in MRL/lpr mice, indicating a promising therapeutic strategy for NPSLE.

Inhibiting 3βHSD1 to eliminate the oncogenic effects of progesterone in prostate cancer

Prostate cancer continuously progresses following deprivation of circulating androgens originating from the testis and adrenal glands, indicating the existence of oncometabolites beyond androgens. In this study, mass-spectrometry-based screening of clinical specimens and a retrospective analysis on the clinical data of prostate cancer patients indicate the potential oncogenic effects of progesterone in patients. High doses of progesterone activate canonical and non-canonical androgen receptor (AR) target genes. Physiological levels of progesterone facilitate cell proliferation via GATA2. Inhibitors of 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) has been discovered and shown to suppress the generation of progesterone, eliminating its transient and accumulating oncogenic effects. An increase in progesterone is associated with poor clinical outcomes in patients and may be used as a predictive biomarker. Overall, we demonstrate that progesterone acts as an oncogenic hormone in prostate cancer, and strategies to eliminate its oncogenic effects may benefit prostate cancer patients.

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High doses of progesterone activate canonical and non-canonical AR signaling

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Progesterone of physiological levels exerts its chronic oncogenic effect via GATA2

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Targeting 3βHSD1 to suppress progesterone synthesis blocks its oncogenic effects

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Serum progesterone might be a predictive biomarker for abiraterone response

Dopamine receptor D2 antagonism normalizes profibrotic macrophage-endothelial crosstalk in non-alcoholic steatohepatitis

BACKGROUND & AIMS

Currently there is no effective treatment for liver fibrosis, which is one of the main histological determinants of non-alcoholic steatohepatitis (NASH). While Hippo/YAP (Yes-associated protein) signaling is essential for liver regeneration, its aberrant activation frequently leads to fibrosis and tumorigenesis. Unravelling "context-specific" contributions of YAP in liver repair might help selectively bypass fibrosis and preserve the pro-regenerative YAP function in hepatic diseases.

METHODS

We used murine liver fibrosis and minipig NASH models, and liver biopsies from patients with cirrhosis. Single-cell RNA-sequencing (scRNA-Seq) was performed, and a G-protein-coupled receptor (GPCR) ligand screening system was used to identify cell-selective YAP inhibitors.

RESULTS

YAP levels in macrophages are increased in the livers of humans and mice with liver fibrosis. The increase in type I interferon and attenuation of hepatic fibrosis observed in mice specifically lacking Yap1 in myeloid cells provided further evidence for the fibrogenic role of macrophage YAP. ScRNA-Seq further showed that defective YAP pathway signaling in macrophages diminished a fibrogenic vascular endothelial cell subset that exhibited profibrotic molecular signatures such as angiocrine CTGF and VCAM1 expression. To specifically target fibrogenic YAP in macrophages, we utilized a GPCR ligand screening system and identified a dopamine receptor D2 (DRD2) antagonist that selectively blocked YAP in macrophages but not hepatocytes. Genetic and pharmacological targeting of macrophage DRD2 attenuated liver fibrosis. In a large animal (minipig) NASH model recapitulating human pathology, the DRD2 antagonist blocked fibrosis and restored hepatic architecture.

CONCLUSIONS

DRD2 antagonism selectively targets YAP-dependent fibrogenic crosstalk between macrophages and CTGF⁺VCAM1⁺ vascular niche, promoting liver regeneration over fibrosis in both rodent and large animal models.

LAY SUMMARY

Fibrosis in the liver is one of the main histological determinants of non-alcoholic steatohepatitis (NASH), a disease paralleling a worldwide surge in metabolic syndromes. Our study demonstrates that a macrophage-specific deficiency in Yes-associated protein (YAP) attenuates liver fibrosis. Dopamine receptor D2 (DRD2) antagonism selectively blocks YAP in macrophages and thwarts liver fibrosis in both rodent and large animal models, and thus holds potential for the treatment of NASH.

Inhibition of GATA2 in prostate cancer by a clinically available small molecule

Castration-resistant prostate cancer (CRPC) remains highly lethal and in need of novel, actionable therapeutic targets. The pioneer factor GATA2 is a significant prostate cancer (PC) driver and is linked to poor prognosis. GATA2 directly promotes androgen receptor (AR) gene expression (both full-length and splice-variant) and facilitates AR binding to chromatin, recruitment of coregulators, and target gene transcription. Unfortunately, there is no clinically applicable GATA2 inhibitor available at the moment. Using a bioinformatics algorithm, we screened in silico 2650 clinically relevant drugs for a potential GATA2 inhibitor. Validation studies used cytotoxicity and proliferation assays, global gene expression analysis, RT-qPCR, reporter assay, reverse phase protein array analysis (RPPA), and immunoblotting. We examined target engagement via cellular thermal shift assay (CETSA), ChIP-qPCR, and GATA2 DNA-binding assay. We identified the vasodilator dilazep as a potential GATA2 inhibitor and confirmed on-target activity via CETSA. Dilazep exerted anticancer activity across a broad panel of GATA2-dependent PC cell lines in vitro and in a PDX model in vivo. Dilazep inhibited GATA2 recruitment to chromatin and suppressed the cell-cycle program, transcriptional programs driven by GATA2, AR, and c-MYC, and the expression of several oncogenic drivers, including AR, c-MYC, FOXM1, CENPF, EZH2, UBE2C, and RRM2, as well as of several mediators of metastasis, DNA damage repair, and stemness. In conclusion, we provide, via an extensive compendium of methodologies, proof-of-principle that a small molecule can inhibit GATA2 function and suppress its downstream AR, c-MYC, and other PC-driving effectors. We propose GATA2 as a therapeutic target in CRPC.

Shaping Chromatin States in Prostate Cancer by Pioneer Transcription Factors

The androgen receptor (AR) is a critical therapeutic target in prostate cancer that responds to antagonists in primary disease, but inevitably becomes reactivated, signaling onset of the lethal castration-resistant prostate cancer (CRPC) stage. Epigenomic investigation of the chromatin environment and interacting partners required for AR transcriptional activity has uncovered three pioneer factors that open up chromatin and facilitate AR-driven transcriptional programs. FOXA1, HOXB13, and GATA2 are required for normal AR transcription in prostate epithelial development and for oncogenic AR transcription during prostate carcinogenesis. AR signaling is dependent upon these three pioneer factors both before and after the clinical transition from treatable androgen-dependent disease to untreatable CRPC. Agents targeting their respective DNA binding or downstream chromatin-remodeling events have shown promise in preclinical studies of CRPC. AR-independent functions of FOXA1, HOXB13, and GATA2 are emerging as well. While all three pioneer factors exert effects that promote carcinogenesis, some of their functions may inhibit certain stages of prostate cancer progression. In all, these pioneer factors represent some of the most promising potential therapeutic targets to emerge thus far from the study of the prostate cancer epigenome.

Inhibition of GATA2 restrains cell proliferation and enhances apoptosis and chemotherapy mediated apoptosis in human GATA2 overexpressing AML cells

GATA2, a zinc finger transcription factor predominantly expressed in hematopoietic cells, acts as an essential regulator of hematopoietic stem cell generation, survival and functionality. Loss and gain of GATA2 expression has been implicated in myelodysplastic syndrome and acute myeloid leukemia (AML) yet the precise biological impact of GATA2 expression on human AML cell fate decisions remains ambiguous. Herein, we performed large-scale bioinformatics that demonstrated relatively frequent GATA2 overexpression in AML patients as well as select human AML (or AML-like) cell lines. By using shRNAi to target GATA2 in these AML cell lines, and an AML cell line expressing normal levels of GATA2, we found that inhibition of GATA2 caused attenuated cell proliferation and enhanced apoptosis exclusively in AML cell lines that overexpress GATA2. We proceeded to pharmacologically inhibit GATA2 in concert with AML chemotherapeutics and found this augmented cell killing in AML cell lines that overexpress GATA2, but not in an AML cell line expressing normal levels of GATA2. These data indicate that inhibition of GATA2 enhances chemotherapy-mediated apoptosis in human AML cells overexpressing GATA2. Thus, we define novel insights into the oncogenic role of GATA2 in human AML cells and suggest the potential utilization of transient GATA2 therapeutic targeting in AML.

Cellular and Molecular Mechanisms Underlying Prostate Cancer Development: Therapeutic Implications

Prostate cancer is the most frequent nonskin cancer and second most common cause of cancer-related deaths in man. Prostate cancer is a clinically heterogeneous disease with many patients exhibiting an aggressive disease with progression, metastasis, and other patients showing an indolent disease with low tendency to progression. Three stages of development of human prostate tumors have been identified: intraepithelial neoplasia, adenocarcinoma androgen-dependent, and adenocarcinoma androgen-independent or castration-resistant. Advances in molecular technologies have provided a very rapid progress in our understanding of the genomic events responsible for the initial development and progression of prostate cancer. These studies have shown that prostate cancer genome displays a relatively low mutation rate compared with other cancers and few chromosomal loss or gains. The ensemble of these molecular studies has led to suggest the existence of two main molecular groups of prostate cancers: one characterized by the presence of ERG rearrangements (~50% of prostate cancers harbor recurrent gene fusions involving ETS transcription factors, fusing the 5' untranslated region of the androgen-regulated gene TMPRSS2 to nearly the coding sequence of the ETS family transcription factor ERG) and features of chemoplexy (complex gene rearrangements developing from a coordinated and simultaneous molecular event), and a second one characterized by the absence of ERG rearrangements and by the frequent mutations in the E3 ubiquitin ligase adapter SPOP and/or deletion of CDH1, a chromatin remodeling factor, and interchromosomal rearrangements and SPOP mutations are early events during prostate cancer development. During disease progression, genomic and epigenomic abnormalities accrued and converged on prostate cancer pathways, leading to a highly heterogeneous transcriptomic landscape, characterized by a hyperactive androgen receptor signaling axis.

NF-κB and GATA-Binding Factor 6 Repress Transcription of Caveolins in Bladder Smooth Muscle Hypertrophy

Caveolins (CAVs) are structural proteins of caveolae that function as signaling platforms to regulate smooth muscle contraction. Loss of CAV protein expression is associated with impaired contraction in obstruction-induced bladder smooth muscle (BSM) hypertrophy. In this study, microarray analysis of bladder RNA revealed down-regulation of CAV1, CAV2, and CAV3 gene transcription in BSM from models of obstructive bladder disease in mice and humans. We identified and characterized regulatory regions responsible for CAV1, CAV2, and CAV3 gene expression in mice with obstruction-induced BSM hypertrophy, and in men with benign prostatic hyperplasia. DNA affinity chromatography and chromatin immunoprecipitation assays revealed a greater increase in binding of GATA-binding factor 6 (GATA-6) and NF-κB to their cognate binding motifs on CAV1, CAV2, and CAV3 promoters in obstructed BSM relative to that observed in control BSM. Knockout of NF-κB subunits, shRNA-mediated knockdown of GATA-6, or pharmacologic inhibition of GATA-6 and NF-κB in BSM increased CAV1, CAV2, and CAV3 transcription and promoter activity. Conversely, overexpression of GATA-6 decreased CAV2 and CAV3 transcription and promoter activity. Collectively, these data provide new insight into the mechanisms by which CAV gene expression is repressed in hypertrophied BSM in obstructive bladder disease.

Reducing Inflammatory Cytokine Production from Renal Collecting Duct Cells by Inhibiting GATA2 Ameliorates Acute Kidney Injury

Acute kidney injury (AKI) is a leading cause of chronic kidney disease. Proximal tubules are considered to be the primary origin of pathogenic inflammatory cytokines in AKI. However, it remains unclear whether other cell types, including collecting duct (CD) cells, participate in inflammatory processes. The transcription factor GATA2 is specifically expressed in CD cells and maintains their cellular identity. To explore the pathophysiological function of GATA2 in AKI, we generated renal tubular cell-specific Gata2 deletion (G2CKO) mice and examined their susceptibility to ischemia reperfusion injury (IRI). Notably, G2CKO mice exhibited less severe kidney damage, with reduced granulomacrophagic infiltration upon IRI. Transcriptome analysis revealed that a series of inflammatory cytokine genes were downregulated in GATA2-deficient CD cells, suggesting that GATA2 induces inflammatory cytokine expression in diseased kidney CD cells. Through high-throughput chemical library screening, we identified a potent GATA inhibitor. The chemical reduces cytokine production in CD cells and protects the mouse kidney from IRI. These results revealed a novel pathological mechanism of renal IRI, namely, that CD cells produce inflammatory cytokines and promote IRI progression. In injured kidney CD cells, GATA2 exerts a proinflammatory function by upregulating inflammatory cytokine gene expression. GATA2 can therefore be considered a therapeutic target for AKI.

Induction of erythropoietin gene expression in epithelial cells by chemicals identified in GATA inhibitor screenings

Erythropoietin (EPO) is a hormone that promotes proliferation, differentiation and survival of erythroid progenitors. EPO gene expression is regulated in a tissue-specific and hypoxia-inducible manner and is mainly restricted to renal EPO-producing cells after birth. Chronic kidney disease (CKD) confers high risk for renal anemia due to lower EPO production from injured kidneys. In transgenic reporter lines of mice, disruption of a GATA-binding motif within the Epo gene promoter-proximal region restores constitutive reporter expression in epithelial cells. Here, mitoxantrone and its analogues, identified as GATA factor inhibitors through high-throughput chemical library screenings, markedly induce EPO/Epo gene expression in epithelium-derived cell lines and mice regardless of oxygen levels. In contrast, mitoxantrone interferes with hypoxia-induced EPO gene expression in Hep3B cells. Cryptic promoters are created for the EPO/Epo gene expression in epithelial cells upon mitoxantrone treatment, and consequently, unique 5'-untranslated regions are generated. The mitoxantrone-induced aberrant transcripts contribute to the reporter protein production in epithelial cells that carry the reporter gene in the proper reading frame of mouse Epo gene. Thus, EPO production in uninjured adult epithelial cells may be a therapeutic approach for renal anemia in patients with CKD.

Crosstalk of the Androgen Receptor with Transcriptional Collaborators: Potential Therapeutic Targets for Castration-Resistant Prostate Cancer

Prostate cancer is the second leading cause of death from cancer among males in Western countries. It is also the most commonly diagnosed male cancer in Japan. The progression of prostate cancer is mainly influenced by androgens and the androgen receptor (AR). Androgen deprivation therapy is an established therapy for advanced prostate cancer; however, prostate cancers frequently develop resistance to low testosterone levels and progress to the fatal stage called castration-resistant prostate cancer (CRPC). Surprisingly, AR and the AR signaling pathway are still activated in most CRPC cases. To overcome this problem, abiraterone acetate and enzalutamide were introduced for the treatment of CRPC. Despite the impact of these drugs on prolonged survival, CRPC acquires further resistance to keep the AR pathway activated. Functional molecular studies have shown that some of the AR collaborative transcription factors (TFs), including octamer transcription factor (OCT1), GATA binding protein 2 (GATA2) and forkhead box A1 (FOXA1), still stimulate AR activity in the castration-resistant state. Therefore, elucidating the crosstalk between the AR and collaborative TFs on the AR pathway is critical for developing new strategies for the treatment of CRPC. Recently, many compounds targeting this pathway have been developed for treating CRPC. In this review, we summarize the AR signaling pathway in terms of AR collaborators and focus on pyrrole-imidazole (PI) polyamide as a candidate compound for the treatment of prostate cancer.

Endothelial LSP1 Modulates Extravascular Neutrophil Chemotaxis by Regulating Nonhematopoietic Vascular PECAM-1 Expression

During inflammation, leukocyte-endothelial cell interactions generate molecular signals that regulate cell functions. The Ca(2+)- and F-actin-binding leukocyte-specific protein 1 (LSP1) expressed in leukocytes and nonhematopoietic endothelial cells is pivotal in regulating microvascular permeability and leukocyte recruitment. However, cell-specific function of LSP1 during leukocyte recruitment remains elusive. Using intravital microscopy of cremasteric microvasculature of chimeric LSP1-deficient mice, we show that not neutrophil but endothelial LSP1 regulates neutrophil transendothelial migration and extravascular directionality without affecting the speed of neutrophil migration in tissue in response to CXCL2 chemokine gradient. The expression of PECAM-1-sensitive α6β1 integrins on the surface of transmigrated neutrophils was blunted in mice deficient in endothelial LSP1. Functional blocking studies in vivo and in vitro elucidated that α6β1 integrins orchestrated extravascular directionality but not the speed of neutrophil migration. In LSP1-deficient mice, PECAM-1 expression was reduced in endothelial cells, but not in neutrophils. Similarly, LSP1-targeted small interfering RNA silencing in murine endothelial cells mitigated mRNA and protein expression of PECAM-1, but not ICAM-1 or VCAM-1. Overexpression of LSP1 in endothelial cells upregulated PECAM-1 expression. Furthermore, the expression of transcription factor GATA-2 that regulates endothelial PECAM-1 expression was blunted in LSP1-deficient or LSP1-silenced endothelial cells. The present study unravels endothelial LSP1 as a novel cell-specific regulator of integrin α6β1-dependent neutrophil extravascular chemotactic function in vivo, effective through GATA-2-dependent transcriptional regulation of endothelial PECAM-1 expression.

Anti-inflammatory effect of the blueberry anthocyanins malvidin-3-glucoside and malvidin-3-galactoside in endothelial cells

Blueberry fruits have a wide range of health benefits because of their abundant anthocyanins, which are natural antioxidants. The purpose of this study was to investigate the inhibitory effect of blueberry's two main anthocyanins (malvidin-3-glucoside and malvidin-3-galactoside) on inflammatory response in endothelial cells. These two malvidin glycosides could inhibit tumor necrosis factor-alpha (TNF-α) induced increases of monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) production both in the protein and mRNA levels in a concentration-dependent manner. Mv-3-glc at the concentration of 1 μM could inhibit 35.9% increased MCP-1, 54.4% ICAM-1, and 44.7% VCAM-1 protein in supernatant, as well as 9.88% MCP-1 and 48.6% ICAM-1 mRNA expression (p<0.05). In addition, they could decrease IκBα degradation (Mv-3-glc, Mv-3-gal, and their mixture at the concentration of 50 μM had the inhibition rate of 84.8%, 75.3%, and 43.2%, respectively, p<0.01) and block the nuclear translocation of p65, which suggested their anti-inflammation mechanism was mediated by the nuclear factor-kappa B (NF-κB) pathway. In general malvidin-3-glucoside had better anti-inflammatory effect than malvidin-3-galactoside. These results indicated that blueberry is good resource of anti-inflammatory anthocyanins, which can be promising molecules for the development of nutraceuticals to prevent chronic inflammation in many diseases.

The cholesterol metabolite 27-hydroxycholesterol promotes atherosclerosis via proinflammatory processes mediated by estrogen receptor alpha

Oxysterols are cholesterol metabolites that serve multiple functions in lipid metabolism, including as liver X receptor (LXR) ligands. 27-hydroxycholesterol (27HC) is an abundant oxysterol metabolized by CYP7B1. How 27HC impacts vascular health is unknown. We show that elevations in 27HC via cyp7b1 deletion promote atherosclerosis in apoe(-/-) mice without altering lipid status; furthermore, estrogen-related atheroprotection is attenuated. In wild-type mice, leukocyte-endothelial cell adhesion is increased by 27HC via estrogen receptor (ER)-dependent processes. In monocytes/macrophages, 27HC upregulates proinflammatory genes and increases adhesion via ERα. In endothelial cells, 27HC is also proadhesive via ERα, and in contrast to estrogen, which blunts NF-κB activation, 27HC stimulates NF-κB activation via Erk1,2 and JNK-dependent IκBα degradation. Whereas 27HC administration to apoe(-/-) mice increases atherosclerosis, apoe(-/-);erα(-/-) are unaffected. Thus, 27HC promotes atherosclerosis via proinflammatory processes mediated by ERα, and it attenuates estrogen-related atheroprotection. Strategies to lower 27HC may complement approaches targeting cholesterol to prevent vascular disease.

A low-molecular-weight compound K7174 represses hepcidin: possible therapeutic strategy against anemia of chronic disease

Hepcidin is the principal iron regulatory hormone, controlling the systemic absorption and remobilization of iron from intracellular stores. The expression of the hepcidin gene, HAMP, is increased in patients with anemia of chronic disease. Previously, the synthetic compound K7174 was identified through chemical screening as a novel inhibitor of the adhesion of monocytes to cytokine-stimulated endothelial cells. K7174 also ameliorated anemia induced by inflammatory cytokines in mice, which suggests a possible involvement of hepcidin regulation. The present study was performed to assess the impact of K7174 on hepcidin expression in a human hematoma cell line and in mice in vivo. We first demonstrated that K7174 treatment in HepG2 cells significantly decreased HAMP expression. Then, we conducted microarray analysis to determine the molecular mechanism by which K7174 inhibits HAMP expression. Transcriptional profiling confirmed the downregulation of HAMP. Surprisingly, we found that K7174 strongly induced GDF15, known as a negative regulator of HAMP expression. Western blotting analysis as well as ELISA confirmed the induction of GDF15 by K7174 treatment. Furthermore, K7174-mediated HAMP suppression was rescued by the silencing of GDF15 expression. Interestingly, we found that K7174 also upregulates CEBPB. Promoter analysis and chromatin immunoprecipitation analysis revealed that CEBPB could contribute to K7174-mediated transcriptional activation of GDF15. Subsequently, we also examined whether K7174 inhibits hepcidin expression in mice. Quantitative RT-PCR analysis with liver samples from K7174-treated mice demonstrated significant upregulation of Gdf15 and downregulation of Hamp expression, as compared to control mice. Furthermore, serum hepcidin concentration was also significantly decreased in K7174-treated mice. In conclusion, K7174 inhibits hepcidin expression partly by inducing GDF15. K-7174 may be a potential therapeutic option to treat anemia of chronic disease.

The novel orally active proteasome inhibitor K-7174 exerts anti-myeloma activity in vitro and in vivo by down-regulating the expression of class I histone deacetylases

Bortezomib therapy is now indispensable for multiple myeloma, but is associated with patient inconvenience due to intravenous injection and emerging drug resistance. The development of orally active proteasome inhibitors with distinct mechanisms of action is therefore eagerly awaited. Previously, we identified homopiperazine derivatives as a novel class of proteasome inhibitors with a different mode of proteasome binding from bortezomib. In this study, we show that K-7174, one of proteasome inhibitory homopiperazine derivatives, exhibits a therapeutic effect, which is stronger when administered orally than intravenously, without obvious side effects in a murine myeloma model. Moreover, K-7174 kills bortezomib-resistant myeloma cells carrying a β5-subunit mutation in vivo and primary cells from a patient resistant to bortezomib. K-7174 induces transcriptional repression of class I histone deacetylases (HDAC1, -2, and -3) via caspase-8-dependent degradation of Sp1, the most potent transactivator of class I HDAC genes. HDAC1 overexpression ameliorates the cytotoxic effect of K-7174 and abrogates histone hyperacetylation without affecting the accumulation of ubiquitinated proteins in K-7174-treated myeloma cells. Conversely, HDAC inhibitors enhance the activity of K-7174 with an increase in histone acetylation. These results suggest that class I HDACs are critical targets of K-7174-induced cytotoxicity. It is highly anticipated that K-7174 increases the tolerability and convenience of patients by oral administration and has the clinical utility in overcoming bortezomib resistance as a single agent or in combination with HDAC inhibitors.

Homopiperazine derivatives as a novel class of proteasome inhibitors with a unique mode of proteasome binding

The proteasome is a proteolytic machinery that executes the degradation of polyubiquitinated proteins to maintain cellular homeostasis. Proteasome inhibition is a unique and effective way to kill cancer cells because they are sensitive to proteotoxic stress. Indeed, the proteasome inhibitor bortezomib is now indispensable for the treatment of multiple myeloma and other intractable malignancies, but is associated with patient inconvenience due to intravenous injection and emerging drug resistance. To resolve these problems, we attempted to develop orally bioavailable proteasome inhibitors with distinct mechanisms of action and identified homopiperazine derivatives (HPDs) as promising candidates. Biochemical and crystallographic studies revealed that some HPDs inhibit all three catalytic subunits (ß 1, ß 2 and ß 5) of the proteasome by direct binding, whereas bortezomib and other proteasome inhibitors mainly act on the ß5 subunit. Proteasome-inhibitory HPDs exhibited cytotoxic effects on cell lines from various hematological malignancies including myeloma. Furthermore, K-7174, one of the HPDs, was able to inhibit the growth of bortezomib-resistant myeloma cells carrying a ß5-subunit mutation. Finally, K-7174 had additive effects with bortezomib on proteasome inhibition and apoptosis induction in myeloma cells. Taken together, HPDs could be a new class of proteasome inhibitors, which compensate for the weak points of conventional ones and overcome the resistance to bortezomib.

Hypoxia-inducible factor stabilizers and other small-molecule erythropoiesis-stimulating agents in current and preventive doping analysis

Increasing the blood's capacity for oxygen transport by erythropoiesis-stimulating agents (ESAs) constitutes a prohibited procedure of performance enhancement according to the World Anti-Doping Agency (WADA). The advent of orally bio-available small-molecule ESAs such as hypoxia-inducible factor (HIF) stabilizers in the development of novel anti-anaemia therapies expands the list of potential ESA doping techniques. Here, the erythropoiesis-stimulating properties and doping relevance of experimental HIF-stabilizers, such as cobaltous chloride, 3,4-dihydroxybenzoic acid or GSK360A, amongst others, are discussed. The stage of clinical trials is reviewed for the anti-anaemia drug candidates FG-2216, FG-4592, GSK1278863, AKB-6548, and BAY85-3934. Currently available methods and strategies for the determination of selected HIF stabilizers in sports drug testing are based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). For the support of further analytical assay development, patents claiming distinct compounds for the use in HIF-mediated therapies are evaluated and exemplary molecular structures of HIF stabilizers presented. Moreover, data concerning the erythropoiesis-enhancing effects of the GATA inhibitors K7174 and K11706 as well as the lipidic small-molecule ESA PBI-1402 are elucidated the context of doping analysis.

Tanshinone IIA inhibits TNF-α-mediated induction of VCAM-1 but not ICAM-1 through the regulation of GATA-6 and IRF-1

The goal of this study was to investigate the differential effect of tanshinone IIA on the induction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by TNF-α and the possible molecular mechanisms by which it regulates ICAM-1 and VCAM-1 expression differentially. Stimulation of human umbilical vein endothelial cells (HUVEC) with TNF-α increased ICAM-1 and VCAM-1 expressions, and the pretreatment with tanshinone IIA concentration dependently inhibited VCAM-1 expression but not ICAM-1 expression. In previous study, PI3K/Akt, PKC and Jak/STAT-3 pathways were involved in the TNF-α-mediated induction of VCAM-1 but not ICAM-1. Thus, we examined the effect of tanshinone IIA on TNF-α-mediated activations of PI3K/Akt, PKC and Jak/STAT-3 pathways. Tanshinone IIA efficiently inhibited the phosphorylations of Akt, PKC and STAT-3 by TNF-α. Moreover, we determined the effect of tanshinone IIA on IRF-1 or GATAs induction and binding activity to VCAM-1 promoter since the upstream promoter region of VCAM-1 but not ICAM-1 contains IRF-1 and GATA binding motifs. Western blot analysis and ChIP assay showed that tanshinone IIA efficiently inhibited TNF-α-increased nuclear level of IRF-1 and GATA-6 and their binding affinity to VCAM-1 promoter region. Taken together, tanshinone IIA selectively inhibits TNF-α-mediated expression of VCAM-1 but not ICAM-1 through modulation of PI3/Akt, PKC and Jak/STAT-3 pathway as well as IRF-1 and GATA-6 binding activity.

Flavonoids inhibit high glucose-induced up-regulation of ICAM-1 via the p38 MAPK pathway in human vein endothelial cells

Recently, several flavonoids have been shown to have cardioprotective, cancer preventive, or anti-inflammatory properties. However, the specific mechanisms underlying their protective effects remain unclear. We aimed to investigate the different effects of three representative flavonoids-hesperidin, naringin, and resveratrol-on intracellular adhesion molecule-1 (ICAM-1) induction in human umbilical vein endothelial cells (HUVECs) by using high-glucose (HG) concentrations and the possible underlying molecular mechanisms. In HG-induced HUVEC cultures, the effects of three different flavonoids on ICAM-1 production and p38 phosphorylation were examined in the presence or absence of inhibitors targeting the mitogen-activated protein kinase (MAPK) signal transduction pathway. HG stimulation of HUVECs increased the levels of the adhesion molecules ICAM-1 and endothelial selectin (E-selectin). Pretreatment with all the three flavonoids drastically inhibited ICAM-1 expression in a time-dependent manner, but did not alter VCAM-1 and E-selectin expressions. Moreover, we investigated the effects of flavonoids on the MAPK signal transduction pathway, because MAPK families are associated with vascular inflammation under stress. These flavonoids did not block HG-induced phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but completely inhibited the HG-induced phosphorylation of p38 MAPK. SB202190, an inhibitor of p38 MAPK, also inhibited the HG-induced enrichment of ICAM-1. This study demonstrated that hesperidin, naringin, and resveratrol reduced the HG-induced ICAM-1 expression via the p38 MAPK signaling pathway, contributing to the inhibition of monocyte adhesion to endothelial cells.

Biphasic, bidirectional regulation of NF-kappaB by endoplasmic reticulum stress

Endoplasmic reticulum (ER) stress induces an adaptive program called the unfolded protein response (UPR), which affects activity of an array of kinases and transcription factors. Previous reports provided evidence for activation of nuclear factor-kappaB (NF-kappaB), the major transcription factor regulating inflammatory processes, by ER stress. However, recent investigation also suggested that preceding ER stress suppresses activation of NF-kappaB by subsequent exposure to inflammatory stimuli. Although ER stress induces activation of NF-kappaB in the early phase, consequent UPR may inhibit NF-kappaB-dependent cellular activation in the later phase. This article summarizes current knowledge on potential mechanisms underlying the biphasic, bidirectional regulation of NF-kappaB by ER stress.

Anthocyanins from black soybean seed coats preferentially inhibit TNF-alpha-mediated induction of VCAM-1 over ICAM-1 through the regulation of GATAs and IRF-1

Adhesion molecules have a key role in pathological inflammation. Thus, we investigated the effect of anthocyanins on the induction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by TNF-alpha and the possible molecular mechanisms by which anthocyanins differentially regulate ICAM-1 and VCAM-1 expression. Stimulation of cells with TNF-alpha increased ICAM-1 and VCAM-1 expression, and pretreatment with anthocyanins inhibited VCAM-1 expression, but not ICAM-1 expression. We found that IRF-1 and GATAs, especially GATA-4 and -6, were involved in the TNF-alpha-mediated expression of VCAM-1 but not ICAM-1, and anthocyanins decreased nuclear levels of GATA-4 and GATA-6 as well as IRF-1. Moreover, pretreatment with a Jak/STAT inhibitor decreased TNF-alpha-induced VCAM-1 expression and nuclear GATA-4, GATA-6, and IRF-1 levels. Furthermore, anthocyanins efficiently inhibited the phosphorylation of STAT-3. This suggests that anthocyanins differentially regulate TNF-alpha-mediated expression of VCAM-1 and ICAM-1 through modulation of the GATA and IRF-1 binding activity via Jak/STAT-3 activation.

Unexpected blockade of adipocyte differentiation by K-7174: implication for endoplasmic reticulum stress

Preadipocytes constitutively express GATA-2 and GATA-3 that are required to halt the cells at the undifferentiated stage. However, we unexpectedly found that K-7174, a GATA-specific inhibitor, did not induce but rather inhibited differentiation of 3T3-L1 preadipocytes. It was associated with lack of lipid accumulation, blunted expression of adipocyte markers including adiponectin and peroxisome proliferator-activated receptor gamma (PPARgamma), and sustained expression of a preadipocyte marker monocyte chemoattractant protein 1 (MCP-1). Subsequent experiments revealed that K-7174 had the potential to induce endoplasmic reticulum (ER) stress evidenced by induction of GRP78 and CHOP. Other inducers of ER stress completely reproduced the effects of K-7174 including suppression of lipid accumulation, blockade of induction of adiponection and PPARgamma and maintenance of MCP-1 expression. These results indicated a possibility that ER stress suppresses adipocyte differentiation and that GATA inhibitor K-7174 has the potential for interfering with adipogenesis through induction of ER stress.

Suppression of cytokine response by GATA inhibitor K-7174 via unfolded protein response

K-7174, a GATA-specific inhibitor, is a putative anti-inflammatory agent that attenuates effects of inflammatory cytokines in certain cell types. However, molecular mechanisms involved have not been elucidated. We found that, in glomerular podocytes, induction of monocyte chemoattractant protein 1 (MCP-1) and inducible nitric oxide synthase (iNOS) by TNF-alpha was abrogated by K-7174. It was correlated with unexpected induction of unfolded protein response (UPR) evidenced by: (1) induction of endogenous indicators 78 kDa glucose-regulated protein and CCAAT/enhancer-binding protein-homologous protein, and (2) suppression of an exogenous indicator, endoplasmic reticulum stress-repressive alkaline phosphatase. In podocytes, induction of UPR by either tunicamycin, thapsigargin, A23187 or AB5 subtilase cytotoxin completely reproduced the suppressive effect of K-7174. Furthermore, K-7174-elicited UPR abrogated induction of MCP-1 and iNOS not only by TNF-alpha but also by medium conditioned by activated macrophages. These results suggested a novel, UPR-dependent mechanism underlying the anti-inflammatory potential of K-7174.

Amelioration of lacrimal gland inflammation by oral administration of K-13182 in Sjögren's syndrome model mice

Regulation of the adhesion of mononuclear cells to endothelial cells is considered to be a critical step for the treatment of inflammatory diseases, including autoimmune diseases. K-13182 was identified as a novel inhibitor for these adhesions. K-13182 inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1, CD106) on human umbilical vein endothelial cells (HUVECs) and on mouse vascular endothelial cell line (MAECs) induced by tumour necrosis factor (TNF)-alpha. K-13182 also inhibited the adhesion of mononuclear cells to these HUVECs and MAECs, indicating that K-13182 suppressed these adhesions mediated by cellular adhesion molecules including VCAM-1. To evaluate the therapeutic effect in autoimmune disease model mice, K-13182 was orally administered to non-obese diabetic (NOD) mice as Sjögren's syndrome (SS) model mice. Severe destructive inflammatory lesions were observed in the lacrimal glands of vehicle-treated control mice; however, 8-week administration of K-13182 inhibited the mononuclear cell infiltration into the inflammatory lesions of the lacrimal glands. In K-13182-treated mice, the decrease in tear secretion was also prevented compared to the control mice. In addition, the apoptosis and the expression of FasL (CD178), perforin, and granzyme A was suppressed in the lacrimal glands of K-13182-treated mice. Therefore, K-13182 demonstrated the possibility of therapeutic efficacy for the inflammatory region of autoimmune disease model mice. These data reveal that VCAM-1 is a promising target molecule for the treatment of autoimmune diseases as a therapeutic strategy and that K-13182 has the potential as a new anti-inflammatory drug for SS.

Essential role of GATA transcriptional factors in the activation of mast cells

Mast cells are pivotal effector cells in IgE-mediated allergic reactions. GATA transcriptional factors such as GATA-1 and GATA-2 are expressed in mast cells, and recent studies have revealed that both GATA-1 and GATA-2 are required for mast cell development. However, the role of GATA transcriptional factors in differentiated mast cells has remained largely unknown. In this study, we repressed the activity of GATA-1 and GATA-2 by using three different approaches (inducible overexpression of a dominant-negative form of GATA, pharmacological inactivation, or small interfering RNA technology), and analyzed the molecular mechanisms of GATA transcriptional factors in the activation of mast cells. Surprisingly, the repression of GATA activity in differentiated mast cells led to the impairment of cell survival, IgE-induced degranulation, and cytokine production. Signal transduction and histone modification in the chromatin related to protein kinase Cbeta were defective in these cells. These results identify that GATA has a critical role in the activation of mast cell.

Functional analysis of an established mouse vascular endothelial cell line

BACKGROUND

In vitrostudies using cell lines are useful for the understanding of cellular mechanisms. The purpose of our study is to develop a new immortalized aortic vascular endothelial cell (EC) line that retains endothelial characteristics and can facilitate the study of ECs.

METHODS

A mouse aortic vascular EC line (MAEC) was established from p53-deficient mouse aorta and cultured for over 100 passages. The expression of endothelial markers was assessed, and the function of this cell line was analyzed by tube formation and binding assays.

RESULTS

MAEC retained many endothelial properties such as cobblestone appearance, contact-inhibited growth, active uptake of acetylated low-density lipoprotein, existence of Weibel-Palade bodies and several EC markers. MAECs exhibited tube formation activity both in vitro and in vivo. Furthermore, crucially, tumor necrosis factor alpha, an inflammatory cytokine, promoted lymphocyte adhesion to MAECs, suggesting that MAECs may facilitate the study of atherosclerosis and local inflammatory reactions in vitro.

CONCLUSION

We describe the morphological and cell biological characteristics of MAEC, providing strong evidence that it retained endothelial properties. This novel cell line can be a useful tool for studying the biology of ECs.

Histone deacetylase inhibitor reduces monocyte adhesion to endothelium through the suppression of vascular cell adhesion molecule-1 expression

OBJECTIVE

Tumor necrosis factor (TNF)-alpha initiates numerous changes in endothelial cell (EC) gene expression that contributes to the pathology of various diseases including inflammation. We hypothesized that TNF-alpha-mediated gene induction involves multiple signaling pathways, and that inhibition of one or more of these pathways may selectively target subsets of TNF-alpha-responsive genes and functions.

METHODS AND RESULTS

Human umbilical vein endothelial cells (ECs) were preincubated with inhibitors of PI3 kinase (LY294002), histone deacetylases (HDAC) (trichostatin A [TSA]), de novo protein synthesis (CHX), proteasome (MG-132), and GATA factors (K-11430) before exposure to TNF-alpha at 4 hours and analyzed by microarray. TNF-alpha-mediated induction of vascular cell adhesion molecule-1 (VCAM-1) was attenuated by all of these inhibitors, whereas in contrast, stimulation of intercellular adhesion molecule-1 (ICAM-1) was blocked by MG-132 alone. Moreover TSA blocked TNF-alpha-mediated induction of monocyte adhesion both in vitro and in vivo through the suppression of VCAM-1. Further analysis demonstrated that HDAC3 plays a significant role in the regulation of TNF-alpha-mediated VCAM-1 expression.

CONCLUSIONS

TNF-alpha activates ECs via multiple signaling pathways, and these pathways may be selectively targeted to modulate EC function. Moreover, TSA treatment reduced monocyte adhesion via VCAM-1 suppression in vitro and in vivo, suggesting that TSA might be useful for the attenuation of the inflammatory response in EC.

Phosphorylation of GATA2 by Akt increases adipose tissue differentiation and reduces adipose tissue-related inflammation: a novel pathway linking obesity to atherosclerosis

BACKGROUND

Obesity-related inflammation is emerging as a major cause of insulin resistance and cardiovascular diseases. GATA2 transcription factor is an inhibitor of adipogenesis and an activator of vascular cells. We hypothesized that GATA2 activity is controlled by insulin during adipogenesis, linking metabolic homeostasis and inflammation.

METHODS AND RESULTS

We show that insulin induces GATA2 phosphorylation on serine 401 in a PI-3K/Akt-dependent manner. Insulin-dependent phosphorylation of serine 401 impairs GATA2 translocation to the nucleus and its DNA binding activity. A GATA2 mutant not phosphorylable by Akt (GATA2(S401A)) acts similarly to wild-type GATA2. In contrast, a GATA2 mutant that mimics Akt phosphorylation (GATA2(S401D)) is restrained in the cytoplasm. Cultured preadipocytes bearing GATA2(S401A) do not convert to adipocytes and express high levels of inflammatory cytokines like monocyte chemotactic protein-1 (MCP-1). On the contrary, GATA2(S401D) preadipocytes differentiate to adipocytes. When GATA2(S401A) preadipocytes are injected in mice fed a high-fat diet, they do not differentiate adequately into adipocytes, maintaining the expression of inflammatory markers like MCP-1. In contrast, injection of GATA2(S401D) preadipocytes in mice fed a high-fat diet results in development of adipocytes and no expression of inflammatory markers.

CONCLUSIONS

GATA2 could be a new target in the prevention and treatment of obesity-related inflammation and its complications.

Macrophage colony-stimulating factor expression in retrovirally transduced cells is dependent upon both the adherence status of the target cells and its 5′ flanking untranslated region

Numerous cell types retrovirally transduced with macrophage colony-stimulating factor (M-CSF) using LXSN-based vectors showed a variable expression of the transgene. Expression of M-CSF correlated with the cells' adherent status. Transduced adherent cells produced the M-CSF, whereas the non-adherent cells synthesized little M-CSF. Studies showed that the 5'-UTR of the M-CSF gene regulated transgenic M-CSF gene expression. Ligation of this 5'-UTR to the enhanced green fluorescent protein gene (EGFP) caused the expression of EGFP to show the same dichotomy as previously seen with the M-CSF. Transgenic M-CSF was expressed within non-adherent cells when the 5'-UTR was removed from the LXSN vector. Quantitative real-time polymerase chain reaction analysis confirmed that lesser production of M-CSF mRNA occurred within the non-adherent cells than in the adherent cells. This difference was eliminated when the 5'-UTR was removed from the retroviral vector. Our work suggests that this 5'-UTR of the M-CSF gene could be an important way to get transgenic expression within adherent cells, but not in non-adherent cells.

Oral administration of K-11706 inhibits GATA binding activity, enhances hypoxia-inducible factor 1 binding activity, and restores indicators in an in vivo mouse model of anemia of chronic disease

Erythropoietin (Epo) gene expression is under the control of hypoxia-inducible factor 1 (HIF-1), and is negatively regulated by GATA. Interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α), which increase the binding activity of GATA and inhibit Epo promoter activity, are increased in patients with anemia of chronic disease (ACD). We previously demonstrated the ability of K-7174 (a GATA-specific inhibitor), when injected intraperitoneally, to improve Epo production that had been inhibited by IL-1β or TNF-α treatment. In the present study, we examined the ability of both K-11706, which inhibits GATA and enhances HIF-1 binding activity, and K-13144, which has no effect on GATA or HIF-1 binding activity, to improve Epo production following inhibition by IL-1β or TNF-α in Hep3B cells in vitro and in an in vivo mouse assay. Oral administration of K-11706 reversed the decreases in hemoglobin and serum Epo concentrations, reticulocyte counts, and numbers of erythroid colony-forming units (CFU-Es) induced by IL-1β or TNF-α. These results raise the possibility of using orally administered K-11706 for treating patients with ACD.

Phenyl Methimazole Inhibits TNF-α-Induced VCAM-1 Expression in an IFN Regulatory Factor-1-Dependent Manner and Reduces Monocytic Cell Adhesion to Endothelial Cells

Proinflammatory cytokine (e.g., TNF-alpha)-induced expression of endothelial cell adhesion molecules (ECAMs) on the lumenal surface of the vascular endothelium and a consequent increase in leukocyte adhesion are key aspects of pathological inflammation. A promising therapeutic approach to diminish aberrant leukocyte adhesion is, therefore, to inhibit cytokine-induced ECAM expression at the transcription level. Several studies suggest that methimazole, a compound used clinically to treat autoimmune diseases, such as Graves' disease, may also diminish pathological inflammation by suppressing ECAM expression. In this study we probed the hypothesis that a derivative of methimazole, phenyl methimazole (compound 10), can reduce cytokine-induced ECAM expression and consequent leukocyte adhesion. We found that compound 10 1) dramatically inhibits TNF-alpha-induced VCAM-1 mRNA and protein expression in human aortic endothelial cells (HAEC), has a relatively modest inhibitory effect on TNF-alpha induced E-selectin expression and has no effect on ICAM-1 expression; 2) significantly reduces TNF-alpha-induced monocytic (U937) cell adhesion to HAEC under in vitro flow conditions similar to that present in vivo; 3) inhibits TNF-alpha-induced IFN regulatory factor-1 binding to VCAM-1 promoter; and 4) reduces TNF-alpha-induced IRF-1 expression in HAEC. Combined, the results indicate that phenyl methimazole can reduce TNF-alpha-induced VCAM-1 expression in an IFN regulatory factor-1-dependent manner and that this contributes significantly to reduced monocytic cell adhesion to TNF-alpha-activated HAEC.

The tea flavonoid epigallocatechin-3-gallate reduces cytokine-induced VCAM-1 expression and monocyte adhesion to endothelial cells

Attachment of leukocytes to the vascular endothelium and the subsequent migration of cells into the vessel wall are early events in atherogenesis. This process requires the expression of endothelial adhesion molecules. Since tea catechins are reputed to promote antiatherogenic activities, we investigated the effects of various tea catechins-i.e., epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG)-on cytokine-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin) in HUVECs by ELISA. EGCG and to a lesser extent ECG prevented the induction of VCAM-1 expression in a concentration-dependent manner after stimulation with TNF-alpha, whereas EC and EGC were without effect. EGCG also inhibited the IL-1beta-induced induction of VCAM-1 expression. Inhibition of cytokine-induced VCAM-1 expression was manifested already on the transcriptional level. Furthermore, EGCG reduced the TNF-alpha-induced adhesion of THP-1 cells to HUVECs. EGCG did not influence TNF-alpha-stimulated NF-kappaB activation.

Selective Inhibition of Endothelial and Monocyte Redox-Sensitive Genes by AGI-1067: A Novel Antioxidant and Anti-Inflammatory Agent

Atherosclerosis is a disease of oxidative stress and inflammation. AGI-1067 [butanedioic acid, mono[4-[[1-[[3,5-bis(1,1-dimethylethyl)-4-,hydroxyphenyl]thio]-1-methylethyl]thio]-2,6-bis (1,1-dimethylethyl)phenyl] ester] is a metabolically stable derivative of, yet pharmacologically distinct from, the antioxidant drug probucol. It is a member of a novel class of orally active, antioxidant, anti-inflammatory compounds termed vascular protectants and exhibits antiatherosclerotic properties in multiple animal models and in humans. To elucidate its antiatherosclerotic mechanisms, we have evaluated several cellular and molecular properties of AGI-1067 in vitro. AGI-1067 exhibited potent lipid peroxide antioxidant activity comparable with probucol yet demonstrated significantly enhanced cellular uptake over that observed with probucol. AGI-1067, but not probucol, inhibited basal levels of reactive oxygen species (ROS) in cultured primary human endothelial cells and both basal and hydrogen peroxide-induced levels of ROS in the promonocytic cell line, U937. Furthermore, AGI-1067 inhibited the inducible expression of the redox-sensitive genes, vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1, in endothelial cells as well as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6 production in peripheral blood mononuclear cells, whereas probucol had no effect. cDNA array hybridization experiments demonstrated that AGI-1067 selectively inhibited the expression of only a subset of TNF-alpha-responsive and nuclear factor-kappaB (NF-kappaB)-inducible genes in endothelial cells. The inhibitory effect of AGI-1067 on inducible VCAM-1 gene expression occurred at the transcriptional level, yet AGI-1067 had no effect on the activation of the redox-sensitive transcription factor NF-kappaB. These studies suggest that the anti-inflammatory and antiatherosclerotic properties of AGI-1067 may be due to selective inhibition of redox-sensitive endothelial and monocyte inflammatory gene expression. These studies provide a molecular basis for understanding the mechanism of action of this new class of therapeutic antiatherosclerotic compounds.

A GATA-specific inhibitor (K-7174) rescues anemia induced by IL-1beta, TNF-alpha, or L-NMMA

Interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), or N(G)-monomethyl-L-arginine (L-NMMA) are increased in patients with chronic disease-related anemia. They increase the binding activity of GATA and inhibit erythropoietin (Epo) promoter activity. In this study, we examined the ability of K-7174 (a GATA-specific inhibitor) to improve Epo production when inhibited by treatment with IL-1beta, TNF-alpha, or L-NMMA. Epo protein production and promoter activity were induced in Hep3B cells with 1% O2. However, 15 U/ml IL-1beta, 220 U/ml TNF-alpha, or 10(-3) M L-NMMA inhibited Epo protein production and promoter activity, respectively. Addition of 10 microM K-7174 rescued these inhibitions of Epo protein production and promoter activity induced by IL-1beta, TNF-alpha, or L-NMMA, respectively. Electrophoretic mobility shift assays revealed that addition of K-7174 decreased GATA binding activity, which was increased with the addition of IL-1beta, TNF-alpha, or L-NMMA. Furthermore, intraperitoneal injection of mice with IL-1beta or TNF-alpha decreased the hemoglobin concentrations and reticulocyte counts. However, the addition of K-7174 reversed these effects. These results raise the possibility of using K-7174 as therapy to treat anemia.

The biology of the Ets1 proto-oncogene

The Ets1 proto-oncoprotein is a member of the Ets family of transcription factors that share a unique DNA binding domain, the Ets domain. The DNA binding activity of Ets1 is controlled by kinases and transcription factors. Some transcription factors, such as AML-1, regulate Ets1 by targeting its autoinhibitory module. Others, such as Pax-5, alter Ets1 DNA binding properties. Ets1 harbors two phosphorylation sites, threonine-38 and an array of serines within the exon VII domain. Phosphorylation of threonine-38 by ERK1/2 activates Ets1, whereas phosphorylation of the exon VII domain by CaMKII or MLCK inhibits Ets1 DNA binding activity. Ets1 is expressed by numerous cell types. In haemotopoietic cells, it contributes to the regulation of cellular differentiation. In a variety of other cells, including endothelial cells, vascular smooth muscle cells and epithelial cancer cells, Ets1 promotes invasive behavior. Regulation of MMP1, MMP3, MMP9 and uPA as well as of VEGF and VEGF receptor gene expression has been ascribed to Ets1. In tumors, Ets1 expression is indicative of poorer prognosis.

The role of the endothelium in severe sepsis and multiple organ dysfunction syndrome

Severe sepsis, defined as sepsis with acute organ dysfunction, is associated with high morbidity and mortality rates. The development of novel therapies for sepsis is critically dependent on an understanding of the basic mechanisms of the disease. The pathophysiology of severe sepsis involves a highly complex, integrated response that includes the activation of a number of cell types, inflammatory mediators, and the hemostatic system. Central to this process is an alteration of endothelial cell function. The goals of this article are to (1) provide an overview of sepsis and its complications, (2) discuss the role of the endothelium in orchestrating the host response in sepsis, and (3) emphasize the potential value of the endothelium as a target for sepsis therapy.

Anti-atherogenic antioxidants regulate the expression and function of proteasome alpha-type subunits in human endothelial cells

It has been proposed that phenolic antioxidants such as probucol exert their anti-atherogenic effects through scavenging lipid-derived radicals. In this study the potential for genomics to reveal unanticipated pharmacological properties of phenolic antioxidants is explored. It was found that two anti-atherogenic compounds, BO-653 and probucol, inhibited the expression of three alpha-type proteasome subunits, PMSA2, PMSA3, and PMSA4 in human umbilical vein endothelial cells. Here we report that both BO-653 and probucol caused not only inhibition of the mRNA levels of these three subunits but also inhibition of both the gene expression and protein synthesis of the alpha-type subunit, PMSA1. Other subunit components of the proteasome such as the beta-type subunits (PMSB1, PMSB7), the ATPase subunit of 19 S (PMSC6), the non-ATPase subunit of 19 S (PMSD1), and PA28 (PMSE2) were not significantly affected by treatment with these compounds. The specific inhibition of alpha-type subunit expression in response to these antioxidants resulted in functional alterations of the proteasome with suppression of degradation of multiubiquitinated proteins and IkappaBalpha. These results suggest that certain compounds previously classified solely as antioxidants are able to exert potentially important modulatory effects on proteasome function.